Komatsu PC75UU-3 Hydraulic Excavator Shop Manual - PDF DOWNLOAD

SEBM016404

MACHINE MODEL

SERIAL NUMBER

PC75UU-3

15001 and up

•

This shop manual may contain attachments and optional equipment that are not available in your area. Please consult your local Komatsu distributor for those items you may require.

Materials and specifications are subject to change without notice.

•

PC75UU-3 mount the 4D102-1 and 4D95LE-2 engine.

For details of the engine, see the 102 Series and 95-2 Series Engine Shop Manual.

© 2003 1 PC75UU-3All Rights Reserved Printed in Japan 07-03(02)

00-1 (4)

CONTENTS No. of page

01

GENERAL ............................................................................................................ 01-1

10

STRUCTURE AND FUNCTION

20

TESTING AND ADJUSTING ................................................................. 20-1

30

DISASSEMBLY AND ASSEMBLY ..................................................... 30-1

40

MAINTENANCE STANDARD ............................................................... 40-1

90

OTHERS

00-2 2

........................................................... 10-1

............................................................................................................... 90-1

PC75UU-3

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SAFETY

SAFETY NOTICE

SAFETY SAFETY NOTICE IMPORTANT SAFETY NOTICE Proper service and repair is extremely important for safe machine operation. The service and repair techniques recommended by Komatsu and described in this manual are both effective and safe. Some of these techniques require the use of tools specially designed by Komatsu for the specific purpose.

¤

To prevent injury to workers, the symbol is used to mark safety precautions in this manual.

The cautions accompanying these symbols should always be followed carefully. If any dangerous situation arises or may possibly arise, first consider safety, and take the necessary actions to deal with the situation.

GENERAL PRECAUTIONS Mistakes in operation are extremely dangerous.

Read the Operation and Maintenance Manual carefully BEFORE operating the machine.

1. Before carrying out any greasing or repairs, read all the precautions given on the decals which are fixed to the machine.

2. When carrying out any operation, always wear safety shoes and helmet. Do not wear loose work clothes, or clothes with buttons missing.

• •

Always wear safety glasses when hitting parts with a hammer.

Always wear safety glasses when grinding parts with a grinder, etc.

3. If welding repairs are needed, always have a trained, experienced welder carry out the work.

When carrying out welding work, always wear welding gloves, apron, hand shield, cap and other clothes suited for welding work.

4. When carrying out any operation with two or more workers, always agree on the operating procedure before starting. Always inform your fellow workers before starting any step of the operation. Before starting work, hang UNDER REPAIR signs on the controls in the operator's compartment.

5. Keep all tools in good condition and learn the correct way to use them.

6. Decide a place in the repair workshop to keep tools and removed parts. Always keep the tools and parts in their correct places. Always keep the work area clean and make sure that there is no dirt or oil on the floor. Smoke only in the areas provided for smoking. Never smoke while working.

PREPARATIONS FOR WORK 7. Before adding oil or making any repairs, park the machine on hard, level ground, and block the wheels or tracks to prevent the machine from moving.

8. Before starting work, lower blade, ripper, bucket or any other work equipment to the ground. If this is not possible, insert the safety pin or use blocks to prevent the work equipment from falling. In addition, be sure to lock all the control levers and hang warning signs on them.

9. When disassembling or assembling, support the machine with blocks, jacks or stands before starting work.

10.Remove all mud and oil from the steps or other places used to get on and off the machine.

Always use the handrails, ladders or steps when getting on or off the machine. Never jump on or off the machine. If it is impossible to use the handrails, ladders or steps, use a stand to provide safe footing.

00-3

SAFETY

PRECAUTIONS DURING WORK 11. When removing the oil filler cap, drain plug or hydraulic pressure measuring plugs, loosen them slowly to prevent the oil from spurting out.

Before disconnecting or removing components of the oil, water or air circuits, first remove the pressure completely from the circuit.

12.The water and oil in the circuits are hot when the engine is stopped, so be careful not to get burned.

Wait for the oil and water to cool before carrying out any work on the oil or water circuits.

13.Before starting work, remove the leads from the battery. Always remove the lead from the negative (–) terminal first.

14.When raising heavy components, use a hoist or crane.

Check that the wire rope, chains and hooks are free from damage.

Always use lifting equipment which has ample capacity.

Install the lifting equipment at the correct places.

Use a hoist or crane and operate slowly to prevent the component from hitting any other part.

Do not work with any part still raised by the hoist or crane.

15.When removing covers which are under internal pressure or under pressure from a spring, always leave two bolts in position on opposite sides. Slowly release the pressure, then slowly loosen the bolts to remove.

16.When removing components, be careful not to break or damage the wiring. Damaged wiring may cause electrical fires.

17.When removing piping, stop the fuel or oil from spilling out. If any fuel or oil drips onto the floor, wipe it up immediately. Fuel or oil on the floor can cause you to slip, or can even start fires.

18.As a general rule, do not use gasoline to wash parts. In particular, use only the minimum of gasoline when washing electrical parts.

00-4

SAFETY NOTICE

19.Be sure to assemble all parts again in their original places.

Replace any damaged parts with new parts. • When installing hoses and wires, be sure that they will not be damaged by contact with other parts when the machine is being operated.

20.When installing high pressure hoses, make sure that they are not twisted. Damaged tubes are dangerous, so be extremely careful when installing tubes for high pressure circuits. Also, check that connecting parts are correctly installed.

21.When assembling or installing parts, always use the specified tightening torques. When installing protective parts such as guards, or parts which vibrate violently or rotate at high speed, be particularly careful to check that they are installed correctly.

22.When aligning two holes, never insert your fingers or hand. Be careful not to get your fingers caught in a hole.

23.When measuring hydraulic pressure, check that the measuring tool is correctly assembled before taking any measurements.

24.Take care when removing or installing the tracks of track-type machines.

When removing the track, the track separates suddenly, so never let anyone stand at either end of the track.

FOREWORD

GENERAL

FOREWORD GENERAL This shop manual has been prepared as an aid to improve the quality of repairs by giving the serviceman an accurate understanding of the product and by showing him the correct way to perform repairs and make judgements. Make sure you understand the contents of this manual and use it to full effect at every opportunity.

This shop manual mainly contains the necessary technical information for operations performed in a service workshop. For ease of understanding, the manual is divided into the following chapters; these chapters are further divided into the each main group of components.

STRUCTURE AND FUNCTION This section explains the structure and function of each component. It serves not only to give an understanding of the structure, but also serves as reference material for troubleshooting.

In addition, this section may contain hydraulic circuit diagrams, electric circuit diagrams, and maintenance standards.

TESTING AND ADJUSTING This section explains checks to be made before and after performing repairs, as well as adjustments to be made at completion of the checks and repairs.

Troubleshooting charts correlating "Problems" with "Causes" are also included in this section.

DISASSEMBLY AND ASSEMBLY This section explains the procedures for removing, installing, disassembling and assembling each component, as well as precautions for them.

MAINTENANCE STANDARD This section gives the judgment standards for inspection of disassembled parts.

The contents of this section may be described in STRUCTURE AND FUNCTION. OTHERS This section mainly gives hydraulic circuit diagrams and electric circuit diagrams.

In addition, this section may give the specifications of attachments and options together.

NOTICE The specifications contained in this shop manual are subject to change at any time and without any advance notice. Use the specifications given in the book with the latest date.

00-5

FOREWORD

HOW TO READ THE SHOP MANUAL

HOW TO READ THE SHOP MANUAL

REVISED EDITION MARK

VOLUMES Shop manuals are issued as a guide to carrying out repairs. They are divided as follows:

W h en a m an u a l is r e vis ed , a n e d itio n ma rk ( ....) is recorded on the bottom of the pages.

Chassis volume: Issued for every machine model Engine volume: Issued for each engine series Each issued as one Electrical volume: Attachments volume: ¡ volume to cover all models

REVISIONS

}

These various volumes are designed to avoid duplicating the same information. Therefore, to deal with all repairs for any model , it is necessary that chassis, engine, electrical and attachment volumes be available.

DISTRIBUTION AND UPDATING Any additions, amendments or other changes will be sent to KOMATSU distributors. Get the most up-todate information before you start any work.

FILING METHOD 1. See the page number on the bottom of the page.

File the pages in correct order.

2. Following examples show how to read the page number.

Example 1 (Chassis volume): 10 - 3 Item number (10. Structure and Function) Consecutive page number for each item.

Example 2 (Engine volume): 12 - 5 Unit number (1. Engine) Item number (2. Testing and Adjusting) Consecutive page number for each item.

3. Additional pages: Additional pages are indicated by a hyphen (-) and number after the page number. File as in the example.

Example: 12-203 10-4 12-203-1 10-4-1 Added pages 12-203-2 10-4-2 12-204 10-5

00-6

123

Revised pages are shown in the LIST OF REVISED PAGES next to the CONTENTS page.

SYMBOLS So that the shop manual can be of ample practical use, important safety and quality portions are marked with the following symbols.

Symbol

Item

Remarks

¤

Safety

Special safety precautions are necessary when performing the work.

Caution

Special technical precautions or other precautions for preserving standards are necessary when performing the work.

Weight

Weight of parts of systems. Caution necessary when selecting hoisting wire, or when working posture is important, etc.

Tightening torque

Places that require special attention for the tightening torque during assembly.

Coat

Places to be coated with adhesives and lubricants, etc.

Oil, water

Places where oil, water or fuel must be added, and the capacity.

Drain

Places where oil or water m u s t b e d r a i n e d , a nd quantity to be drained.

s

4 3 2 5 6

FOREWORD

HOISTING INSTRUCTIONS

HOISTING INSTRUCTIONS HOISTING

¤ •

Heavy parts (25 kg or more) must be lifted with a hoist, etc. In the DISASSEMBLY AND ASSEMBLY section, every part weighing 25 kg or more is indicated clearly with the symbol

4

If a part cannot be smoothly removed from the machine by hoisting, the following checks should be made: 1) Check for removal of all bolts fastening the part to the relative parts.

2) Check for existence of another part causing interference with the part to be removed.

WIRE ROPES 1) Use adequate ropes depending on the weight of parts to be hoisted, referring to the table below: Wire ropes (Standard "Z" or "S" twist ropes without galvanizing) Rope diameter

★

Allowable load

mm

kN

tons

10 11.5 12.5 14 16 18 20 22.4 30 40 50 60

9.8 13.7 15.7 21.6 27.5 35.3 43.1 54.9 98.1 176.5 274.6 392.2

1.0 1.4 1.6 2.2 2.8 3.6 4.4 5.6 10.0 18.0 28.0 40.0

Slinging near the edge of the hook may cause the rope to slip off the hook during hoisting, and a serious accident can result. Hooks have maximum strength at the middle portion.

100%

88%

79%

71%

41% SAD00479

3) Do not sling a heavy load with one rope alone, but sling with two or more ropes symmetrically wound onto the load.

Slinging with one rope may cause turning of the load during hoisting, untwisting of the rope, or slipping of the rope from its original winding position on the load, which can result in a dangerous accident.

¤

4) Do not sling a heavy load with ropes forming a wide hanging angle from the hook.

When hoisting a load with two or more ropes, the force subjected to each rope will increase with the hanging angles. The table below shows the variation of allowable load kN {kg} when hoisting is made with two ropes, each of which is allowed to sling up to 9.8 kN {1000 kg} vertically, at various hanging angles.

When two ropes sling a load vertically, up to 19.6 kN {2000 kg} of total weight can be suspended. This weight becomes 9.8 kN {1000 kg} when two ropes make a 120° hanging angle.

On the other hand, two ropes are subjected to an excessive force as large as 39.2 kN {4000 kg} if they sling a 19.6 kN {2000 kg} load at a lifting angle of 150°.

The allowable load value is estimated to be onesixth or one-seventh of the breaking strength of the rope used.

2) Sling wire ropes from the middle portion of the hook.

00-7

FOREWORD

METHOD OF DISASSEMBLING, CONNECTING PUSH-PULL TYPE COUPLER

METHOD OF DISASSEMBLING, CONNECTING PUSH-PULL TYPE COUPLER

¤ ¤

Before carrying out the following work, release the residual pressure from the hydraulic tank.

For details, see TESTING AND ADJUSTING, Releasing residual pressure from hydraulic tank.

Even if the residual pressure is released from the hydraulic tank, some hydraulic oil flows out when the hose is disconnected. Accordingly, prepare an oil receiving container.

Disconnection 1) Release the residual pressure from the hydraulic tan k. Fo r d e tails , se e TES TIN G AN D ADJUSTING, Releasing residual pressure from hydraulic tank.

2) Hold adapter (1) and push hose joint (2) into mating adapter (3). (See Fig. 1) ★ The adapter can be pushed in about 3.5 mm. ★ Do not hold rubber cap portion (4).

3) After hose joint (2) is pushed into adapter (3), press rubber cap portion (4) against (3) until it clicks. (See Fig. 2) 4) Hold hose adapter (1) or hose (5) and pull it out.

(See Fig. 3) ★ Since some hydraulic oil flows out, prepare an oil receiving container.

Connection 1) Hold hose adapter (1) or hose (5) and insert it in mating adapter (3), aligning them with each other. (See Fig. 4) ★ Do not hold rubber cap portion (4).

2) After inserting the hose in the mating adapter perfectly, pull it back to check its connecting condition. (See Fig. 5) ★ When the hose is pulled back, the rubber cap portion moves toward the hose about 3.5 mm. This does not indicate abnormality, however.

00-8

Type 1

FOREWORD

METHOD OF DISASSEMBLING, CONNECTING PUSH-PULL TYPE COUPLER

Type 3

1) Hold the mouthpiece of the tightening portion and push body (2) in straight until sliding prevention ring (1) contacts contact surface a of the hexagonal portion at the male end.

1) Hold the mouthpiece of the tightening portion and push body (2) in straight until sliding prevention ring (1) contacts contact surface a of the hexagonal portion at the male end.

2) Hold in the condition in Step 1), and turn lever (4) to the right (clockwise).

2) Hold in the condition in Step 1), and push until cover (3) contacts contact surface a of the hexagonal portion at the male end.

3) Hold in the condition in Steps 1) and 2), and pull out whole body (2) to disconnect it.

3) Hold in the condition in Steps 1) and 2), and pull out whole body (2) to disconnect it.

•

•

Disassembly

Type 2

Hold the mouthpiece of the tightening portion and push body (2) in straight until sliding prevention ring (1) contacts contact surface a of the hexagonal portion at the male end to connect it.

Connection

Hold the mouthpiece of the tightening portion and push body (2) in straight until sliding prevention ring (1) contacts contact surface a of the hexagonal portion at the male end to connect it.

00-9

FOREWORD

COATING MATERIALS

COATING MATERIALS ★ ★

The recommended coating materials such as adhesives, gasket sealants and greases used for disassembly and assembly are listed below.

For coating materials not listed below, use the equivalent of products shown in this list.

Category

Komatsu code

Part No.

Q'ty

Container

LT-1A

790-129-9030

150 g

Tube

LT-1B

790-129-9050

20 g (2 pcs.)

Polyethylene container

LT-2

09940-00030

50 g

Polyethylene container

LT-3

790-129-9060 (Set of adhesive and hardening agent)

Adhesive: 1 kg Hardenin g agent: 500 g

Can

LT-4

790-129-9040

250 g

Polyethylene container

Holtz MH 705

790-126-9120

75 g

Tube

Three bond 1735

790-129-9140

50 g

Polyethylene container

2g

Polyethylene container

Adhesives

Aron-alpha 201

790-129-9130

Loctite 648-50

79A-129-9110

50 cc

Polyethylene container

LG-1

790-129-9010

200 g

Tube

LG-5

790-129-9070

1 kg

Can

Main applications, featuresr •

Used to prevent rubber gaskets, rubber cushions, and cock plug from coming out.

•

Used in places requiring an immediately effective, strong adhesive.

Used for plastics (except polyethylene, polyprophylene, tetrafluoroet hl ene and vi nyl chl oride), rubber, metal and non-metal.

• •

Features: Resistance to heat and chemicals Used for anti-loosening and sealant purpose for bolts and plugs.

•

Used as adhesive or sealant for metal, glass and plastic.

•

Used as sealant for machined holes.

•

Used as heat-resisting sealant for repairing engine.

• • •

Quick hardening type adhesive Cure time: within 5 sec. to 3 min.

Used mainly for adhesion of metals, rubbers, plastics and woods.

• •

Quick hardening type adhesive Quick cure type (max. strength after 30 minutes) Used mainly for adhesion of rubbers, plastics and metals.

• • •

Resistance to heat, chemicals Used at joint portions subject to high temperatures.

•

Used as adhesive or sealant for gaskets and packing of power train case, etc.

•

Used as sealant for various threads, pipe joints, flanges.

Used as sealant for tapered plugs, elbows, nipples of hydraulic piping.

•

Gasket sealant • LG-6

790-129-9020

200 g

Tube

• •

00-10

Features: Silicon based, resistance to heat, cold Used as sealant for flange surface, tread. mab Used as sealant for oil pan, final drive case, etc.

FOREWORD

Category

COATING MATERIALS

Komatsu code

Part No.

Q'ty

Container

Main applications, featuresr •

LG-7

790-129-9070

1g

Tube

Three bond 1211

790-129-9090

100 g

Tube

LM-G

09940-00051

60 g

Can

•

Adhesives

Molybdenum disulphide lubricant

LM-P

09940-00040

200 g

•

Used as heat-resisting sealant for repairing engine.

•

Used as lubricant for sliding portion (to prevent from squeaking).

•

Used to prevent seizure or scuffling of the thread when press fitting or shrink fitting.

Used as lubricant for linkage, bearings, etc.

Tube •

G2-LI

SYG2-400LI SYG2-350LI SYG2-400LI-A SYG2-160LI SYGA-160CNLI

G2-CA

SYG2-400CA SYG2-350CA SYG2-400CA-A SYG2-160CA SYGA-160CNCA

Various

Various

Molybdenum disulphide lubricant

SYG2-400M

400 g (10 per case)

Belows type

Grease

Various

Ftures: Silicon based, quick hardening type Used as sealant for flywheel housing, intake manifold, oil an, thermostat housing, etc.

•

General purpose type

•

Used for normal temperature, light load bearing at places in contact with water or steam.

•

Used for places with heavy load

Various

00-11

FOREWORD

STANDARD TIGHTENING TORQUE

STANDARD TIGHTENING TORQUE STANDARD TIGHTENING TORQUE TABLE (WHEN USING TORQUE WRENCH) ★ In the case of metric nuts and bolts for which there is no special instruction, tighten to the torque given in the table below.

Thread diameter of bolt

Width across flats

mm

mm

6 8 10 12 14

10 13 17 19 22

16 18 20 22 24

24 27 30 32 36

27 30 33 36 39

41 46 50 55 60

Thread diameter of bolt

Width across flats

mm

mm

Nm

6 8 10 12

10 13 14 27

7.85 1.95 18.6 4.9 40.2 5.9 82.35 7.85

Nm

kgm

0 0.15 0 0.3 0 0.7 01 02 28.5 0 3 39 0 4 56 0 6 76 0 8.5 94.5 0 10.5 135 0 15 175 0 20 225 0 25 280 0 30 335 0 35

0 1.4 03 07 0 10 0 19 279 0 30 382 0 39 549 0 59 745 0 83 927 0 103 1320 0 140 1720 0 190 2210 0 240 2750 0 290 3290 0 340

1.35 3.2 6.7 11.5 18

13.2 31 66 113 177

kgm

0 0 0 0

0.8 1.9 4.1 8.4

0 0.2 0 0.5 0 0.6 0 0.8

Sealing surface

TABLE OF TIGHTENING TORQUES FOR FLARED NUTS ★ In the case of flared nuts for which there is no special instruction, tighten to the torque given in the table below.

SAD00483

Thread diameter

Width across flat

mm

mm

Nm

kgm

14 18 22 24 30 33 36 42

19 24 27 32 36 41 46 55

24.5 4.9 49 19.6 78.5 19.6 137.3 29.4 176.5 29.4 196.1 49 245.2 49 294.2 49

2.5 0.5 5 2 8 2 14 3 18 3 20 5 25 5 30 5

00-12

Tightening torque

0 0 0 0 0 0 0 0

0 0 0 0 0 0 0 0

FOREWORD

STANDARD TIGHTENING TORQUE

TABLE OF TIGHTENING TORQUES FOR SPLIT FLANGE BOLTS ★ In the case of split flange bolts for which there is no special instruction, tighten to the torque given in the table below.

Thread diameter

Width across flat

Tightening torque

mm

mm

Nm

kgm

10 12 16

14 17 22

65.7 6.8 112 9.8 279 29

0 0 0

6.7 0.7 11.5 1 28.5 3

0

0 0

TABLE OF TIGHTENING TORQUES FOR O-RING BOSS PIPING JOINTS ★ Unless there are special instructions, tighten the O-ring boss piping joints to the torque below.

Thread diameter

Width across flat

Tightening torque

mm

mm

Nm

14 20 24 33 42

Varies depending on type of connector.

34.3 4.9 93.1 9.8 142.1 19.6 421.4 58.8 877.1 132.3

Norminal No.

02 03, 04 05, 06 10, 12 14

kgm

0 0 0 0 0

0 0.5 01 02 06 0 13.5

3.5 9.5 14.5 43 89.5

TABLE OF TIGHTENING TORQUES FOR O-RING BOSS PLUGS ★ Unless there are special instructions, tighten the O-ring boss plugs to the torque below.

Thread diameter

Width across flat

Tightening torque

mm

mm

Nm

kgm

08 10 12 14 16 18 20 24 30 33 36 42 52

14 17 19 22 24 27 30 32 32 n 36 n n

7.35 1.47 11.27 1.47 17.64 1.96 22.54 1.96 29.4 4.9 39.2 4.9 49 4.9 68.6 9.8 107.8 14.7 127.4 19.6 151.9 24.5 210.7 29.4 323.4 44.1

0 0 0 0 0 0 0 0 0 0 0 0 0

0.75 0.15 1.15 0.15 1.8 0.2 2.3 0.2 3 0.5 4 0.5 5 0.5 7 1 11 1.5 13 2 15.5 2.5 21.5 3 33 4.5

Norminal No.

08 10 12 14 16 18 20 24 30 33 36 42 52

0 0 0 0 0 0 0 0 0 0 0 0 0

00-13

FOREWORD

STANDARD TIGHTENING TORQUE

TIGHTENING TORQUE FOR 102 ENGINE SERIES 1) BOLT AND NUTS Use these torques for bolts and nuts (unit: mm) of Cummins Engine.

Thread diameter

Tightening torque

mm

Nm

6 8 10 12

10 2 24 4 43 6 77 12

kgm

0 0 0 0

1.02 2.45 4.38 7.85

0 0.20 0 0.41 0 0.61 0 1.22

2) EYE JOINTS Use these torques for eye joints (unit: mm) of Cummins Engine.

Thread diameter

Tightening torque

mm

Nm

6 8 10 12 14

8 2 10 2 12 2 24 4 36 5

kgm

0 0 0 0 0

0.81 1.02 1.22 2.45 3.67

0 0.20 0 0.20 0 0.20 0 0.41 0 0.51

3) TAPERED SCREWS Use these torques for tapered screws (unit: inch) of Cummins Engine.

Thread diameter

Tightening torque

inch

Nm

1 / 16 1/8 1/4 3/8 1/2 3/4 1

3 1 8 2 12 2 15 2 24 4 36 5 60 9

kgm

0 0 0 0 0 0 0

0.31 0.81 1.22 1.53 2.45 3.67 6.12

0 0.10 0 0.20 0 0.20 0 0.41 0 0.41 0 0.51 0 0.92

TIGHTENING TORQUE TABLE FOR HOSES (TAPER SEAL TYPE AND FACE SEAL TYPE) ★ Tighten the hoses (taper seal type and face seal type) to the following torque, unless otherwise specified. ★ Apply the following torque when the threads are coated (wet) with engine oil.

Tightening torque (Nm {kgm}) Nominal size Width across of hose flats

Taper seal type

Face seal type

Nominal thread Thread size size - Threads per Root diameter (mm) (mm) (Reference) inch, Thread series

Range

Target

19

35 - 63 {3.5 - 6.5}

44 {4.5}

14

9 – - 18UNF 16

14.3

22

54 - 93 {5.5 - 9.5}

74 {4.5}

–

11 – - 16UN 16

17.5

24

59 - 98 {6.0 - 10.0}

78 {8.0}

18

–

–

04

27

84 - 132 {8.5 - 13.5}

103 {10.5}

22

13 – - 16UN 16

20.7

05

32

128 - 186 {13.0 - 19.0}

157 {16.0}

24

1 - 14UNS

25.4

06

36

177 - 245 {18.0 - 25.0}

216 {22.0}

30

3 1 – - 12UNF 16

30.3

(10)

41

177 - 245 {18.0 - 25.0}

216 {22.0}

33

–

–

(12)

46

197 - 294 {20.0 - 30.0}

245 {25.0}

36

–

–

(14)

55

246 - 343 {25.0 - 35.0}

294 {30.0}

42

–

–

02

03

00-14

FOREWORD

ELECTRIC WIRE CODE

ELECTRIC WIRE CODE In the wiring diagrams, various colors and symbols are employed to indicate the thickness of wires.

This wire code table will help you understand WIRING DIAGRAMS. Example: 5WB indicates a cable having a nominal number 5 and white coating with black stripe.

CLASSIFICATION BY THICKNESS

Copper wire Cable O.D. (mm)

Current rating (A)

Applicable circuit

0.88

2.4

12

Starting, lighting, signal etc.

0.32

2.09

3.1

20

Lighting, signal etc.

65

0.32

5.23

4.6

37

Charging and signal

15

84

0.45

13.36

7.0

59

Starting (Glow plug)

40

85

0.80

42.73

11.4

135

Starting

60

127

0.80

63.84

13.6

178

Starting

100

217

0.80

109.1

17.6

230

Starting

Norminal number

Number of strands

Dia. of strands (mm2)

Cross section (mm 2)

0.85

11

0.32

2

26

5

CLASSIFICATION BY COLOR AND CODE Circuits Priority Classification

1

Primary

Charging

Ground

Starting

Lighting

Instrument

Signal

Other

Code

W

B

B

R

Y

G

L

Color

White

Black

Black

Red

Yellow

Green

Blue

Code

WR

BW

RW

YR

GW

LW

2 Color White & Red Code

WB

3 Color White & Black Code 4

Auxiliary

WL

Color White & Blue Code

WG

5 Color White & Green Code 6 Color

n n

n n n n n n n n n n

White & Black Red & White Rellow & Red Green & White Blue & White BY

RB

YB

GR

LR

Black & Yellow Red & Black Yellow & Black Green & Red Blue & Yellow BR

RY

Black & Red Red & Yellow

n n n n

RG

YG

GY

LY

Yellow & Green

Green & Yellow

Blue & Yellow

YL

GB

LB

Red & Green Yellow & Blue Green & Black Blue & Black RL

YW

GL

Red & Blue Yellow & White Green & Blue

n n 00-15

FOREWORD

CONVERSION TABLE

CONVERSION TABLE METHOD OF USING THE CONVERSION TABLE The Conversion Table in this section is provided to enable simple conversion of figures. For details of the method of using the Conversion Table, see the example given below.

EXAMPLE • Method of using the Conversion Table to convert from millimeters to inches 1. Convert 55 mm into inches.

(1) Locate the number 50 in the vertical column at the left side, take this as , then draw a horizontal line from .

(2) Locate the number 5 in the row across the top, take this as , then draw a perpendicular line down from .

(3) Take the point where the two lines cross as . This point gives the value when converting from millimeters to inches. Therefore, 55 mm = 2.165 inches.

2. Convert 550 mm into inches.

(1) The number 550 does not appear in the table, so divide by 10 (move the decimal point one place to the left) to convert it to 55 mm.

(2) Carry out the same procedure as above to convert 55 mm to 2.165 inches.

(3) The original value (550 mm) was divided by 10, so multiply 2.165 inches by 10 (move the decimal point one place to the right) to return to the original value. This gives 550 mm = 21.65 inches.

A B

C

C

A

B

B Millimeters to inches 1 mm = 0.03937 in

A

00-16

0

1

2

3

4

5

6

7

8

9

0 10 20 30 40

0 0.394 0.787 1.181 1.575

0.039 0.433 0.827 1.220 1.614

0.079 0.472 0.866 1.260 1.654

0.118 0.512 0.906 1.299 1.693

0.157 0.551 0.945 1.339 1.732

0.197 0.591 0.984 1.378 1.772

0.236 0.630 1.024 1.417 1.811

0.276 0.669 1.063 1.457 1.850

0.315 0.709 1.102 1.496 1.890

0.354 0.748 1.142 1.536 1.929

50 60 70 80 90

1.969 2.362 2.756 3.150 3.543

2.008 2.402 2.795 3.189 3.583

2.047 2.441 2.835 3.228 3.622

2.087 2.480 2.874 3.268 3.661

2.126 2.520 2.913 3.307 3.701

2.165 2.559 2.953 3.346 3.740

2.205 2.598 2.992 3.386 3.780

2.244 2.638 3.032 3.425 3.819

2.283 2.677 3.071 3.465 3.858

2.323 2.717 3.110 3.504 3.898

C

FOREWORD

CONVERSION TABLE

Millimeters to Inches 1 mm = 0.03937 in

0

1

2

3

4

5

6

7

8

9

0

0.039

0.079

0.118

0.157

0.197

0.236

0.276

0.315

0.354

10

0.394

0.433

0.472

0.512

0.551

0.591

0.630

0.669

0.709

0.748

20

0.787

0.827

0.866

0.906

0.945

0.984

1.024

1.063

1.102

1.142

30

1.181

1.220

1.260

1.299

1.339

1.378

1.417

1.457

1.496

1.536

40

1.575

1.614

1.654

1.693

1.732

1.772

1.811

1.850

1.890

1.929

50

1.969

2.008

2.047

2.087

2.126

2.165

2.205

2.244

2.283

2.323

60

2.362

2.402

2.441

2.480

2.520

2.559

2.598

2.638

2.677

2.717

70

2.756

2.795

2.835

2.874

2.913

2.953

2.992

3.032

3.071

3.110

80

3.150

3.189

3.228

3.268

3.307

3.346

3.386

3.425

3.465

3.504

90

3.543

3.583

3.622

3.661

3.701

3.740

3.780

3.819

3.858

3.898

0

Kilogram to Pound 1 kg = 2.2046 lb

0 0

0

1

2

3

4

5

6

7

8

9

2.20

4.41

6.61

8.82

11.02

13.23

15.43

17.64

19.84

10

22.05

24.25

26.46

28.66

30.86

33.07

35.27

37.48

39.68

41.89

20

44.09

46.30

48.50

50.71

51.91

55.12

57.32

59.53

61.73

63.93

30

66.14

68.34

70.55

72.75

74.96

77.16

79.37

81.57

83.78

85.98

40

88.18

90.39

92.59

94.80

97.00

99.21

101.41

103.62

105.82

108.03

50

110.23

112.44

114.64

116.85

119.05

121.25

123.46

125.66

127.87

130.07

60

132.28

134.48

136.69

138.89

141.10

143.30

145.51

147.71

149.91

152.12

70

154.32

156.53

158.73

160.94

163.14

165.35

167.55

169.76

171.96

174.17

80

176.37

178.57

180.78

182.98

185.19

187.39

189.60

191.80

194.01

196.21

90

198.42

200.62

202.83

205.03

207.24

209.44

211.64

213.85

216.05

218.26

00-17

FOREWORD

CONVERSION TABLE

Liter to U.S. Gallon 1l = 0.2642 U.S. Gal

0

1

2

3

4

5

6

7

8

9

0

0.264

0.528

0.793

1.057

1.321

1.585

1.849

2.113

2.378

10

2.642

2.906

3.170

3.434

3.698

3.963

4.227

4.491

4.755

5.019

20

5.283

5.548

5.812

6.076

6.340

6.604

6.869

7.133

7.397

7.661

30

7.925

8.189

8.454

8.718

8.982

9.246

9.510

9.774

10.039

10.303

40

10.567

10.831

11.095

11.359

11.624

11.888

12.152

12.416

12.680

12.944

50

13.209

13.473

13.737

14.001

14.265

14.529

14.795

15.058

15.322

15.586

60

15.850

16.115

16.379

16.643

16.907

17.171

17.435

17.700

17.964

18.228

70

18.492

18.756

19.020

19.285

19.549

19.813

20.077

20.341

20.605

20.870

80

21.134

21.398

21.662

21.926

22.190

22.455

22.719

22.983

23.247

23.511

90

23.775

24.040

24.304

24.568

24.832

25.096

25.361

25.625

25.889

26.153

0

Liter to U.K. Gallon 1l = 0.21997 U.K. Gal

0

1

2

3

4

5

6

7

8

9

0

0.220

0.440

0.660

0.880

1.100

1.320

1.540

1.760

1.980

10

2.200

2.420

2.640

2.860

3.080

3.300

3.520

3.740

3.950

4.179

20

4.399

4.619

4.839

5.059

5.279

5.499

5.719

5.939

6.159

6.379

30

6.599

6.819

7.039

7.259

7.479

7.969

7.919

8.139

8.359

8.579

40

8.799

9.019

9.239

9.459

9.679

9.899

10.119

10.339

10.559

10.778

50

10.998

11.281

11.438

11.658

11.878

12.098

12.318

12.528

12.758

12.978

60

13.198

13.418

13.638

13.858

14.078

14.298

14.518

14.738

14.958

15.178

70

15.398

15.618

15.838

16.058

16.278

16.498

16.718

16.938

17.158

17.378

80

17.598

17.818

18.037

18.257

18.477

18.697

18.917

19.137

19.357

19.577

90

19.797

20.017

20.237

20.457

20.677

20.897

21.117

21.337

21.557

21.777

0

00-18

FOREWORD

CONVERSION TABLE

kgm to ft. lb 1 kgm = 7.233 ft. lb

0

1

2

3

4

5

6

7

8

9

0

0

7.2

14.5

21.7

28.9

36.2

43.4

50.6

57.9

65.1

10

72.3

79.6

86.8

94.0

101.3

108.5

115.7

123.0

130.2

137.4

20

144.7

151.9

159.1

166.4

173.6

180.8

188.1

195.3

202.5

209.8

30

217.0

224.2

231.5

238.7

245.9

253.2

260.4

267.6

274.9

282.1

40

289.3

296.6

303.8

311.0

318.3

325.5

332.7

340.0

347.2

354.4

50

361.7

368.9

376.1

383.4

390.6

397.8

405.1

412.3

419.5

426.8

60

434.0

441.2

448.5

455.7

462.9

470.2

477.4

484.6

491.8

499.1

70

506.3

513.5

520.8

528.0

535.2

542.5

549.7

556.9

564.2

571.4

80

578.6

585.9

593.1

600.3

607.6

614.8

622.0

629.3

636.5

643.7

90

651.0

658.2

665.4

672.7

679.9

687.1

694.4

701.6

708.8

716.1

100

723.3

730.5

737.8

745.0

752.2

759.5

766.7

773.9

781.2

788.4

110

795.6

802.9

810.1

817.3

824.6

831.8

839.0

846.3

853.5

860.7

120

868.0

875.2

882.4

889.7

896.9

904.1

911.4

918.6

925.8

933.1

130

940.3

947.5

954.8

962.0

969.2

976.5

983.7

990.9

998.2

1005.4

140

1012.6

1019.9

1027.1

1034.3

1041.5

1048.8

1056.0

1063.2

1070.5

1077.7

150

1084.9

1092.2

1099.4

1106.6

1113.9

1121.1

1128.3

1135.6

1142.8

1150.0

160

1157.3

1164.5

1171.7

1179.0

1186.2

1193.4

1200.7

1207.9

1215.1

1222.4

170

1129.6

1236.8

1244.1

1251.3

1258.5

1265.8

1273.0

1280.1

1287.5

1294.7

180

1301.9

1309.2

1316.4

1323.6

1330.9

1338.1

1345.3

1352.6

1359.8

1367.0

190

1374.3

1381.5

1388.7

1396.0

1403.2

1410.4

1417.7

1424.9

1432.1

1439.4

00-19

FOREWORD

CONVERSION TABLE

kg/cm2 to lb/in2 1kg/cm2 = 14.2233 lb/in2

0

1

2

3

4

5

6

7

8

9

0

0

14.2

28.4

42.7

56.9

71.1

85.3

99.6

113.8

128.0

10

142.2

156.5

170.7

184.9

199.1

213.4

227.6

241.8

256.0

270.2

20

284.5

298.7

312.9

327.1

341.4

355.6

369.8

384.0

398.3

412.5

30

426.7

440.9

455.1

469.4

483.6

497.8

512.0

526.3

540.5

554.7

40

568.9

583.2

597.4

611.6

625.8

640.1

654.3

668.5

682.7

696.9

50

711.2

725.4

739.6

753.8

768.1

782.3

796.5

810.7

825.0

839.2

60

853.4

867.6

881.8

896.1

910.3

924.5

938.7

953.0

967.2

981.4

70

995.6

1010

1024

1038

1053

1067

1081

1095

1109

1124

80

1138

1152

1166

1181

1195

1209

1223

1237

1252

1266

90

1280

1294

1309

1323

1337

1351

1365

1380

1394

1408

100

1422

1437

1451

1465

1479

1493

1508

1522

1536

1550

110

1565

1579

1593

1607

1621

1636

1650

1664

1678

1693

120

1707

1721

1735

1749

1764

1778

1792

1806

1821

1835

130

1849

1863

1877

1892

1906

1920

1934

1949

1963

1977

140

1991

2005

2020

2034

2048

2062

2077

2091

2105

2119

150

2134

2148

2162

2176

2190

2205

2219

2233

2247

2262

160

2276

2290

2304

2318

2333

2347

2361

2375

2389

2404

170

2418

2432

2446

2460

2475

2489

2503

2518

2532

2546

180

2560

2574

2589

2603

2617

2631

2646

2660

2674

2688

190

2702

2717

2731

2745

2759

2773

2788

2802

2816

2830

200

2845

2859

2873

2887

2901

2916

2930

2944

2958

2973

210

2987

3001

3015

3030

3044

3058

3072

3086

3101

3115

220

3129

3143

3158

3172

3186

3200

3214

3229

3243

3257

230

3271

3286

3300

3314

3328

3343

3357

3371

3385

3399

240

3414

3428

3442

3456

3470

3485

3499

3513

3527

3542

00-20

FOREWORD

CONVERSION TABLE

Temperature Fahrenheit-Centigrade Conversion ; a simple way to convert a Fahrenheit temperature reading into a Centigrade temperature reading or vice versa is to enter the accompanying table in the center or boldface column of figures.

These figures refer to the temperature in either Fahrenheit or Centigrade degrees.

If it is desired to convert from Fahrenheit to Centigrade degrees, consider the center column as a table of Fahrenheit temperatures and read the corresponding Centigrade temperature in the column at the left.

If it is desired to convert from Centigrade to Fahrenheit degrees, consider the center column as a table of Centigrade values, and read the corresponding Fahrenheit temperature on the right.

1°C = 33.8°F

°C

°F

°C

°F

°C

°F

°C

°F

–40.4 –37.2 –34.4 –31.7 –28.9

–40 –35 –30 –25 –20

–40.0 –31.0 –22.0 –13.0 –4.0

–11.7 –11.1 –10.6 –10.0 –9.4

11 12 13 14 15

51.8 53.6 55.4 57.2 59.0

7.8 8.3 8.9 9.4 10.0

46 47 48 49 50

114.8 116.6 118.4 120.2 122.0

27.2 27.8 28.3 28.9 29.4

81 82 83 84 85

117.8 179.6 181.4 183.2 185.0

–28.3 –27.8 –27.2 –26.7 –26.1

–19 –18 –17 –16 –15

–2.2 –0.4 1.4 3.2 5.0

–8.9 –8.3 –7.8 –7.2 –6.7

16 17 18 19 20

60.8 62.6 64.4 66.2 68.0

10.6 11.1 11.7 12.2 12.8

51 52 53 54 55

123.8 125.6 127.4 129.2 131.0

30.0 30.6 31.1 31.7 32.2

86 87 88 89 90

186.8 188.6 190.4 192.2 194.0

–25.6 –25.0 –24.4 –23.9 –23.3

–14 –13 –12 –11 –10

6.8 8.6 10.4 12.2 14.0

–6.1 –5.6 –5.0 –4.4 –3.9

21 22 23 24 25

69.8 71.6 73.4 75.2 77.0

13.3 13.9 14.4 15.0 15.6

56 57 58 59 0

132.8 134.6 136.4 138.2 140.0

32.8 33.3 33.9 34.4 35.0

91 92 93 94 95

195.8 197.6 199.4 201.2 203.0

–22.8 –22.2 –21.7 –21.1 –20.6

–9 –8 –7 –6 –5

15.8 17.6 19.4 21.2 23.0

–3.3 –2.8 –2.2 –1.7 –1.1

26 27 28 29 30

78.8 80.6 82.4 84.2 86.0

16.1 16.7 17.2 17.8 18.3

61 62 63 64 65

141.8 143.6 145.4 147.2 149.0

35.6 36.1 36.7 37.2 37.8

96 97 98 99 100

204.8 206.6 208.4 210.2 212.0

–20.0 –19.4 –18.9 –18.3 –17.8

–4 –3 –2 –1 0

24.8 26.6 28.4 30.2 32.0

–0.6 0 0.6 1.1 1.7

31 32 33 34 35

87.8 89.6 91.4 93.2 95.0

18.9 19.4 20.0 20.6 21.1

66 67 68 69 70

150.8 152.6 154.4 156.2 158.0

40.6 43.3 46.1 48.9 51.7

105 110 115 120 125

221.0 230.0 239.0 248.0 257.0

–17.2 –16.7 –16.1 –15.6 –15.0

1 2 3 4 5

33.8 35.6 37.4 39.2 41.0

2.2 2.8 3.3 3.9 4.4

36 37 38 39 40

96.8 98.6 100.4 102.2 104.0

21.7 22.2 22.8 23.3 23.9

71 72 73 74 75

159.8 161.6 163.4 165.2 167.0

54.4 57.2 60.0 62.7 65.6

130 135 140 145 150

266.0 275.0 284.0 293.0 302.0

–14.4 –13.9 –13.3 –12.8 –12.2

6 7 8 9 10

42.8 44.6 46.4 48.2 50.0

5.0 5.6 6.1 6.7 7.2

41 42 43 44 45

105.8 107.6 109.4 111.2 113.0

24.4 25.0 25.6 26.1 26.7

76 77 78 79 80

168.8 170.6 172.4 174.2 176.0

68.3 71.1 73.9 76.7 79.4

155 160 165 170 175

311.0 320.0 329.0 338.0 347.0

00-21

FOREWORD

UNITS

UNITS In this manual, the measuring units are indicated with Internatinal System of units (SI).

As for reference, conventionally used Gravitational System of units are indicated in parentheses { Example: N {kg} Nm {kgm} MPa {kg/cm2} kPa {mmH2O} kPa {mmHg} kW/rpm {HP/rpm} g/kWh {g/HPh}

00-22

}.

01 GENERAL

General assembly drawing .......................... 01- 2 Work equipment range drawing ................. 01- 7 Specifications ............................................... 01-10 Weight table .................................................. 01-16 List of lubricant and water ........................... 01-20

PC75UU-3

01-1 (4)

10 STRUCTURE AND FUNCTION

Radiator, oil cooler ......................................10- 2 PTO (coupling) ............................................10- 4 Power train ..................................................10- 6 Swing machinery ........................................ 10- 7 Swing circle ................................................. 10- 8 Track frame ..................................................10- 9 Hydraulic equipment layout .......................10- 10 Hydraulic tank ............................................. 10- 12 Hydraulic pump .......................................... 10- 13 Control valve ...............................................10- 42 Self-pressure reducing valve ..................... 10- 54 CLSS ............................................................ 10- 58 Swing motor ...............................................10- 76 Center swivel joint ......................................10- 87 Travel motor ................................................ 10- 91 Valve control ...............................................10- 98 PPC valve .....................................................10- 99 Solenoid valve ............................................10-111 Solenoid valve, EPC valve ..........................10-113 Work equipment .........................................10-117 Air conditioner piping ................................10-119 Electric wiring diagram .............................. 10-121 Engine control ............................................. 10-124 Four system (4 system) .............................. 10-132 Electrical control system ............................ 10-150 Monitor system ........................................... 10-157

PC75UU-3

10-1 2

STRUCTURE AND FUNCTION

RADIATOR, OIL COOLER

RADIATOR, OIL COOLER Serial No. : 15001 – 19000

1.

2.

3.

4.

5.

6.

7.

8.

9.

10.

Fan guard Radiator inlet hose Radiator outlet hose Drain valve Oil cooler inlet Oil cooler outlet Oil cooler Radiator Shroud Reserve tank

10-2 2

Specifications Radiator • Core type: CF4-4 • Heat dissipation area: 19.36 m2 • Fin pitch: 4.0/2P • Water volume: 6.2 l • Cracking pressure of pressure valve : 88.3 ± 14.7 kPa {0.9 ± 0.15 kg/cm2} • Cracking pressure of vacuum valve : -4.9 – 0 kPa {-0.05 – 0 kg/cm2}

Oil cooler • Core type: FCI • Heat dissipation area: 7.17 m2 • Fin pitch: 3.5P • Oil volume: 2.0 l

PC75UU-3

STRUCTURE AND FUNCTION

RADIATOR, OIL COOLER

Serial No. : 19001 and up

1.

2.

3.

4.

5.

6.

7.

8.

9.

10.

Fan guard Radiator inlet hose Drain valve Radiator outlet hose Oil cooler inlet Oil cooler outlet Oil cooler Radiator Shroud Reserve tank

PC75UU-3

Specifications Radiator • Core type: CF4-3 • Heat dissipation area: 14.46 m2 • Fin pitch: 4.0/2P • Water volume: 5.8 l • Cracking pressure of pressure valve : 88.3 ± 14.7 kPa {0.9 ± 0.15 kg/cm2} • Cracking pressure of vacuum valve : -4.9 – 0 kPa {-0.05 – 0 kg/cm2}

Oil cooler • Core type: FC1 • Heat dissipation area: 7.17 m2 • Fin pitch: 3.5P • Oil volume: 2.0 l

10-3 2

STRUCTURE AND FUNCTION

PTO (COUPLING)

PTO (COUPLING) Serial No. : 15001 – 19000

1.

2.

3.

4.

Drain plug Shaft Coupling Flywheel

10-4 2

5.

6.

7.

8.

Pump case Cage Level plug Breather/oil filler plug

PC75UU-3

STRUCTURE AND FUNCTION

PTO (COUPLING)

Serial No. : 19001 and up

1.

2.

3.

4.

Drain plug Shaft Coupling Flywheel

PC75UU-3

5.

6.

7.

8.

Pump case Cage Level plug Breather/oil filler plug

10-5 2

STRUCTURE AND FUNCTION

POWER TRAIN

POWER TRAIN 1. Idler 2. Control valve 3. Self-pressure reducing valve 4. Center swivel joint 5. Swing motor 6. Travel motor 7. Gear pump 8. Main pump 9. Engine 10. Mode selection solenoid valve 11. Travel speed boost solenoid valve 12. Brake solenoid valve 13. PPC lock solenoid valve 14. Swing machinery 15. Swing circle

10-6 2

PC75UU-3

STRUCTURE AND FUNCTION

SWING MACHINERY

SWING MACHINERY

1. Swing pinion (No. of teeth: 10) 2. Housing 3. No. 2 planetary carrier 4. No. 2 sun gear (No. of teeth: 19) 5. Ring gear (No. of teeth: 68) 6. No. 1 planetary carrier 7. No. 1 sun gear (No. of teeth: 22) 8. Level gauge 9. Oil filler port 10. Swing motor 11. No. 1 planet gear (No. of teeth: 23) 12. No. 2 planet gear (No. of teeth: 24) 13. Bearing grease nipple 14. Drain plug 15. Swing circle (No. of teeth: 76)

PC75UU-3

Specifications Reduction ratio:

22 + 68 19 + 68 × =18.732 22 19

10-7 2

STRUCTURE AND FUNCTION

SWING CIRCLE

SWING CIRCLE

1.

2.

3.

4.

Swing circle outer race Ball Swing circle inner race Plug

Specifications 76 =7.60 10 Amount of grease: 5 l (G2-LI) Reduction ratio:

Serial No.: 15001 – 19000 5. Grease nipple “S. Inner race, outer race soft zone position “

10-8 2

PC75UU-3

STRUCTURE AND FUNCTION

TRACK FRAME

TRACK FRAME

1.

2.

3.

4.

Idler Track frame Carrier roller Sprocket

PC75UU-3

5.

6.

7.

8.

Travel motor Track roller Track shoe Idler cushion

10-9 2

STRUCTURE AND FUNCTION

HYDRAULIC EQUIPMENT LAYOUT

HYDRAULIC EQUIPMENT LAYOUT 1. Bucket cylinder 2. Arm cylinder 3. Offset cylinder 4. Control valve 5. Boom cylinder 6. Hydraulic tank 7. Gear pump (swing, blade) 8. R.H. work equipment PPC valve 9. Main pump 10. Blade PPC valve 11. R.H. travel motor 12. Oil cooler 13. L.H. travel motor 14. L.H. work equipment PPC valve 15. Swing motor 16. Center swivel joint 17. Mode selection solenoid valve 18. Travel speed boost solenoid valve 19. Swing brake solenoid valve 20. PPC lock solenoid valve 21. Arm IN stop solenoid valve 22. Boom RAISE stop solenoid valve 23. Travel PPC valve 24. Boom LOWER stop solenoid valve 25. L.H. offset stop solenoid valve 26. Offset pc valve 27. Blade cylinder

10-10 2

PC75UU-3

STRUCTURE AND FUNCTION

PC75UU-3

HYDRAULIC EQUIPMENT LAYOUT

10-11 2

STRUCTURE AND FUNCTION

HYDRAULIC TANK

HYDRAULIC TANK

1.

2.

3.

4.

5.

6.

7.

8.

Return filter Safety valve Cap Vacuum valve Pressure valve Sight gauge Suction strainer Drain plug

10-12 2

Specifications Tank capacity: 71 l Amount of oil inside tank: 57 l Cracking pressure of pressure valve : 38.2 ± 14.7 kPa {0.39 ± 0.15 kg/cm2} Cracking pressure of vacuum valve : -4.9 – 0 kPa {-0.05 – 0 kg/cm2} Bypass valve set pressure: 103 ± 19.6 kPa {1.05 ± 0.2 kg/cm2}

PC75UU-3

STRUCTURE AND FUNCTION

HYDRAULIC PUMP

HYDRAULIC PUMP LPV90-SAR(2)32 LPV90-SAR(2)27

Serial No.: 15001 – 19000 Serial No.: 19001 and up

1. Main pump 2. Pump for swing, blade

Specifications

PA PA3 PD1 PDA PGA PGS PLS

Capacity 90.6 + 32.0 cm3/rev 75.5 + 26.8 cm3/rev

: Pump discharge : Swing sensing pilot : Drain : Air bleed : Gear pump discharge : Gear pump suction : Control valve LS pressure inlet PM : L mode selector pilot PPLS : LS pump pressure inlet PS : Pump suction PC75UU-3

Type

Set pressure

LPV90-SAR(2)32

LPV90-SAR(2)27

23.4 MPa {260 kg/cm2}

10-13 2

STRUCTURE AND FUNCTION

HYDRAULIC PUMP

1. MAIN PUMP

PA : Main pump discharge PA3 : Swing sensing pilot PD1 : Drain PDA : Air bleed port PLS : Control valve LS pressure inlet PM : Mode selection solenoid pressure inlet PPLS : LS pump pressure inlet PS : Pump suction

10-14 2

ยก The main pump consists of one unit formed by the pump, servo piston, PC valve, and LS valve.

The explanation in STRUCTURE AND FUNCTION is divided into two parts: the pump and PC valve + LS valve.

PC75UU-3

STRUCTURE AND FUNCTION

1.

2.

3.

4.

5.

Shaft Cradle Case Rocker cam Shoe

PC75UU-3

HYDRAULIC PUMP

6.

7.

8.

9.

10.

Piston Cylinder block Valve plate Spring Servo piston

10-15 2

STRUCTURE AND FUNCTION

HYDRAULIC PUMP

Function • The engine rotation and torque transmitted to the pump shaft is converted into hydraulic energy, and pressurized oil is discharged according to the load.

• It is possible to change the discharge amount by changing the swash plate angle.

Structure • Cylinder block (7) is supported to shaft (1) by spline a, and shaft (1) is supported by the front and rear bearings.

• The tip of piston (6) is a concave ball, and shoe (5) is caulked to it to form one unit.

Piston (6) and shoe (5) form a spherical bearing.

• Rocker cam (4) has flat surface A, and shoe (5) is always pressed against this surface while sliding in a circular movement. Rocker cam (4) brings high pressure oil at cylindrical surface B with cradle (2), which is secured to the case, and forms a static pressure bearing when it slides.

10-16 2

•

•

•

Piston (6) carries out relative movement in the axial direction inside each cylinder chamber of cylinder block (7).

Cylinder block (7) seals the pressure oil to valve plate (8) and carries out relative rotation. This surface is designed so that the oil pressure balance is maintained at a suitable level.

The oil inside each cylinder chamber of cylinder block (7) is sucked in and discharged through valve plate (8).

PC75UU-3

STRUCTURE AND FUNCTION

HYDRAULIC PUMP

Operation 1) Operation of pump • Cylinder block (7) rotates together with shaft (1), and shoe (5) slides on flat surface A. When this happens, rocker cam (4) moves along cylindrical surface B, so angle α between center line X of rocker cam (4) and the axial direction of cylinder block (7) changes. Angle α is called the swash plate angle.

•

Center line X of rocker cam (4) maintains swash plate angle a in relation to the axial direction of cylinder block (7), and flat surface A moves as a cam in relation to shoe (5).

•

In this way, piston (6) slides on the inside of cylinder block (7), so a difference between volume E and F is created inside cylinder block (7). The suction and discharge is carried out by this difference F – E.

•

In other words, when cylinder block (7) rotates and the volume of chamber E becomes smaller, the oil is discharged during that stroke.

At the same time, the volume of chamber F becomes larger, and as the volume becomes larger, oil is sucked in.

(The diagram shows chamber F at the end of the suction process and chamber E at the end of the discharge process.)

•

If center line X of rocker cam (4) is in line with the axial direction of cylinder block (7) (swash plate angle = 0), the difference between volumes E and F inside cylinder block (7) becomes 0, so the pump does not carry out any suction or discharge of oil. (In actual fact, the swash plate angle never becomes 0.)

•

In other words, there is a proportional relationship between swash plate angle α and the pump discharge amount.

PC75UU-3

10-17 2

STRUCTURE AND FUNCTION

HYDRAULIC PUMP

2. Control of discharge amount • If swash plate angle a becomes larger, the difference in volumes E and F becomes larger and discharge volume Q increases.

Swash plate angle a is changed by servo piston (10).

• Servo piston (10) moves in a reciprocal straight line movement under the signal pressure of the PC and LS valves.

This straight line movement is transmitted through slider (13) to rocker cam (4), and rocker cam (4), which is supported by the cylindrical surface to cradle (2), slides in a rotating movement.

•

•

•

With servo piston (10), the area receiving the pressure is different at the left and right, so main pump discharge pressure (self-pressure) PP is always brought to the pressure chamber at the small diameter piston end.

Output pressure PLP of the LS valve is brought to the pressure chamber at the large diameter piston end.

The relationship between the size of pressure PP at the small diameter piston end and pressure PLP at the large diameter piston end, and the ratio between the area receiving the pressure of the small diameter piston and the area receiving the pressure of the large diameter piston controls the movement of servo piston (10).

10-18 2

PC75UU-3

STRUCTURE AND FUNCTION

HYDRAULIC PUMP

2. LS • PC VALVE, SERVO PISTON LS VALVE

PA : Pump PLP : LS control pressure output PLS : LS pressure input PPL : Control pressure input

1.

2.

3.

4.

Sleeve Spool Seat Plug

5. Spring 6. Seat 7. Nut

PC VALVE

PA : Pump PA3 : Swing sensing pilot PDP : Drain PM : Mode selector pressure pilot PPL : Control pressure output

PC75UU-3

1.

2.

3.

4.

5.

6.

Piston Seat Spring Spring Seat Spool

7. Sleeve 8. Washer 9. Pin 10. Nut 11. Nipple

10-19 2

STRUCTURE AND FUNCTION

HYDRAULIC PUMP

LS VALVE Function • The LS valve controls the pump discharge amount according to the amount of movement of the control lever, that is, the oil flow demanded by the actuator.

• The LS valve detects the oil flow demanded by the actuator from the differential pressure »PLS between input pressure Pa2 (Note 1) (downstream pressure of self-pressure reducing valve) of the control valve and control valve outlet pressure PLS, and controls main pump discharge amount Q. (Pa2 is called the LS pump pressure, PLS is called the LS pressure, and»PLS is called the LS differential pressure.)

• In other words, the pressure loss (= LS differential pressure »PLS) generated by the flow of oil from the pump passing through opening area of the control valve spool is detected.

By controlling pump discharge amount Q so that this pressure loss remains constant, a pump discharge amount is supplied in accordance with the demands of the control valve by controlling pump discharge amount Q. • Main pump discharge pressure PP, LS pump pressure Pa2, and LS pressure PLS are brought to the LS valve.

The relationship between pump discharge amount Q and LS differential pressure»PLS changes as shown in the diagram on the right.

Note 1: Previously, the pump discharge pres sure and control valve outlet port pressure were brought to both sides of the LS valve as the LS differential pressure»PLS. However, the LS differential pressure changes according to the differential pressure at the self-pressure reducing valve, so it is necessary to bring theself-pressure reducing valve down stream pressure = control valve inlet port pressure and control valve outlet port pressure to the LS valve.

10-20 2

PC75UU-3

STRUCTURE AND FUNCTION

HYDRAULIC PUMP

OPERATION 1. When control valve is at HOLD position

10-22 2

PC75UU-3

STRUCTURE AND FUNCTION

•

•

•

•

•

The LS pressure PLS is brought from the control valve outlet port to spring chamber a of the LS valve. LS pump pressure Pa2 at the control valve inlet port is brought to chamber b at the tip of the sleeve on the opposite side.

The position of piston (15) is determined by the size of pump pressure Pa2 and the combined force of LS pressure PLS + force of spring (14).

Before the engine is started, servo piston (1) is pushed down (direction of minimum swash plate angle) by spring (3).

After the engine is started, if all the control valves are at the neutral position, no pressure oil flows to the control valve outlet port, so LS pressure PLS is 0 MPa {0 kg/cm2}.

(Spring chamber a is connected to the drain circuit through the control valve spool.)

At the same time, LS pump pressure Pa2 is held at the unload pressure of approx. 2.7 MPa {27 kg/cm2}.

For this reason, piston (15) is pushed to the right (➡), port c and port d are interconnected, and pump pressure PP is brought from port d to chamber X at the large diameter end of servo piston (1).

Pump pressure PP is always supplied to chamber Y at the small diameter end of servo piston (1), but the force applied to the large diameter end of servo piston (1) is greater because of the difference in area at both ends of the piston, so servo piston (1) moves up in the direction of the minimum swash plate angle ( ). ➡

•

HYDRAULIC PUMP

PC75UU-3

10-23 2

STRUCTURE AND FUNCTION

HYDRAULIC PUMP

2. When opening area of control valve is maximum (lever operated fully)

10-24 2

PC75UU-3

STRUCTURE AND FUNCTION

•

•

HYDRAULIC PUMP

When the control lever is operated fully, that is, when the area of opening of the control valve becomes larger, the difference between LS pump pressure Pa2 and LS pressure PLS (LS differential pressure »PLS) becomes smaller.

LS pressure PLS brought to spring chamber a of the LS valve becomes close to LS pump pressure Pa2, and piston (15) is pushed to the left ( ) by the combined force of LS pressure PLS + force of spring (14). This closes port c and interconnects port d and port e.

As a result, the pressurized oil acting on chamber X at the large diameter end of servo piston (1) flows from port d to port e and is connected to port f of the PC valve.

At this point, port f of the PC valve is drained inside the pump case through the inside of the piston, so the pressure in chamber X at the large diameter end of servo piston (1) also becomes the drain pressure.

Because of this, servo piston (1) is moved down in the direction of the maximum swash plate angle ( ) by pump pressure PP acting on chamber Y at the small diameter end of the piston. ➡

•

•

•

➡

PC75UU-3

10-25 2

STRUCTURE AND FUNCTION

HYDRAULIC PUMP

3. When opening area of control valve is small (small movement of lever)

10-26 2

PC75UU-3

STRUCTURE AND FUNCTION

•

When the control lever is operated in small movements, or when it is operated to the HOLD position (in other words, when the area of opening of the control valve becomes smaller), the difference between LS pump pressure Pa2 and LS pressure PLS (in other words, LS pressure »PLS) becomes larger.

When this happens, the movement is the same as for [1. When control valve is at HOLD position]: LS pump pressure Pa2 pushes piston (14) to the right (➡), so servo piston (1) is moved up in the direction of the minimum swash plate angle ( ).

In other words, the basic LS set differential pressure of the LS valve is taken as 1.96 MPa {20 kg/cm2}. In the range from the neutral position of the control valve to the small area of opening of the control valve (fine control), in the area where the LS differential pressure »PLS is more than 1.96 MPa {20 kg/cm2}, the pump swash plate angle moves in the minimum direction.

If the area of opening of the control valve is further increased, and LS differential pressure »PLS goes below 1.96 MPa {20 kg/cm2}, the pump swash plate angle is moved in the maximum direction. ➡

•

HYDRAULIC PUMP

PC75UU-3

10-27 2

STRUCTURE AND FUNCTION

HYDRAULIC PUMP

4. When pump flow is amount demanded by control valve

10-28 2

PC75UU-3

STRUCTURE AND FUNCTION

•

•

•

•

•

•

•

HYDRAULIC PUMP

Let us take the area receiving the pressure at the large diameter end of servo piston as A1, the area receiving the pressure at the small diameter end as A2, the pressure acting on the large piston diameter end as Pen, and the pressure acting on the small piston diameter end as PP. When the flow of oil from the pump reaches the flow demanded by the control valve, LS pump pressure Pa2 acting on port b of the LS valve and the combined force of LS pressure PLS + force of spring (14) acting on spring chamber a are balanced, so piston (15) stops at almost the central position.

As a result, port c, port d, and port e open approximately the same amount, so the pump pressure flows from port c to port d. Part flows from port e to the tank case and is drained, so the pressure is reduced by approx. 1/2 and flows to chamber X at the large diameter end of servo piston (1).

At this point, the relationship between the area receiving the pressure at both ends of piston (1) is A2 : A1 = 1 : 2, so the pressure applied to both ends of servo piston (1) becomes PP : Pen = 2 : 1. This makes the force acting on both ends of servo piston (1) 1 : 1, so servo piston (1) stops in that position and the pump discharge amount is balanced with the oil flow demanded by the control valve.

The force of the spring is adjusted so that Pa2 • 2 – PLS = »PLS = • 1.96 MPa {20 kg/cm } at the point where piston (15) is balanced.

In other words, when the area of opening of control valve is 1/2, the pump swash plate angle is also 1/2, and when the area of opening of control valve is 1/4, the pump swash plate angle is also 1/4. LS differential pressure »PLS is always held at 1.96 MPa {20 kg/ cm2}, so the pump discharge amount is in accordance with the area of opening of the control valve.

For example, after balancing at an area of opening 1/4 of the control valve, if the system is operated to 3/4 of the area of opening of the control valve, LS differential pressure »PLS will drop momentarily.

As a result, the LS valve is actuated and the pump discharge amount is increased, but when the pump swash plate angle rises to 3/4, the LS differential pressure »PLS rises to 1.96 MPa {20 kg/cm2}, so it is balanced in this position.

PC75UU-3

10-29 2

STRUCTURE AND FUNCTION

HYDRAULIC PUMP

PC valve Function • When discharge pressure PP becomes higher, the area of opening of the control valve becomes larger, and even if the LS valve tries to increase pump discharge amount Q, the PC valve carries out control to prevent any increase above fixed discharge amount Q to match discharge pressure PP. It carries out approximate horsepower control to prevent the hydraulic horsepower absorbed by the pump from exceeding the engine horsepower.

• In other words, if the load during operations becomes larger and pump discharge pressure PP rises, pump discharge amount Q is reduced; and if pump discharge pressure PP goes down, pump discharge amount Q is increased.

• The relationship between pump discharge pressure PP and pump discharge amount Q is as shown in the diagram on the right.

Normally, it is set to the pump absorption torque for the standard mode, but if the mode selector solenoid valve signal is input, the pump absorption horsepower is reduced by approx. 20% as shown by the curve for the light load mode.

• The pump for the swing and blade is installed at the rear of the main pump, so when the swing/blade pump is driven, the main pump absorption ttorque is lowered by the amount that the swing/blade pump has absorbed so that the main pump absorption torque + the swing/blade absorption torque becomes the total absorption torque (100%).

10-30 2

PC75UU-3

STRUCTURE AND FUNCTION

HYDRAULIC PUMP

OPERATION 1. When actuator load is large (pump discharge pressure PP is high)

10-32 2

PC75UU-3

STRUCTURE AND FUNCTION

•

HYDRAULIC PUMP

When the load on the actuator becomes high and pump discharge pressure PP rises, piston (8) is pushed to the left ( ) because of the relationship between the cross-sectional area of piston portions S1 and S2 (S1 > S2).

As a result, port f and port g are interconnected, pump pressure PP flows from port g to port f, and at the same time, port f and the drain circuit are shut off.

If the LS valve takes action to increase the pump discharge amount, spool (15) of the LS valve is moved to the left ( ) and port d and port e are interconnected.

As a result, pump pressure PP from port f of the PC valve flows from port e of the LS valve to port d, enters chamber X at the large diameter end of servo piston (1), and stops the movement of servo piston (1).

If pump discharge pressure PP rises further, piston (8) moves to the left ( ) and servo piston (1) moves up in the direction of the minimum swash plate angle because of the pressure in chamber X at the large diameter end.

When servo piston (1) moves up , piston (4) is moved to the right (➡) through lever (2).

As a result, springs (5) and (7) are moved in the direction of compression and piston (8) is pushed back to the right.

When piston (8) is pushed back to the right and port f and port g are shut off, servo piston (1) stops moving up.

The position where servo piston (1) stops is higher (closer to the minimum swash plate angle) than when the pump discharge pressure is low. ➡

•

•

➡

•

•

➡

•

•

•

PC75UU-3

10-33 2

STRUCTURE AND FUNCTION

HYDRAULIC PUMP

2. When actuator load becomes smaller (pump discharge pressure PP drops)

10-34 2

PC75UU-3

STRUCTURE AND FUNCTION

•

•

•

•

HYDRAULIC PUMP

When the load on the actuator becomes smaller and pump discharge pressure PP drops, piston (8) is pushed to the right (➡) by the force of springs (5) and (7).

As a result, port g and port f are shut off, and at the same time, port f is connected to the drain circuit.

When this happens, if the LS valve is acting to increase the pump discharge pressure, the limit of the PC valve disappears, so the pressurized oil in chamber X at the large diameter end of servo piston (1) passes from port d of the LS valve to port e, and flows from port f of the PC valve to the drain circuit as explained in the section on the LS valve.

For this reason, servo piston (1) is moved down in the direction of the maximum swash plate angle by the pressure in chamber Y at the small diameter end.

PC75UU-3

10-35 2

STRUCTURE AND FUNCTION

HYDRAULIC PUMP

3. When mode selector solenoid valve signal pressure is input When operating swing (blade)

10-36 2

PC75UU-3

STRUCTURE AND FUNCTION

HYDRAULIC PUMP

When mode selector solenoid valve signal pressure is input • When the mode selector solenoid valve is turned ON and signal pressure PM is input to port PM, it acts on piston (10) and piston (10) pushes piston (8) to the left ( ).

• As a result, springs (5) and (7) are compressed and the spring load is increased, so the pump absorption torque is reduced by approx. 20%. ➡

When swing (blade) is operated • When the swing is not being used, in other words, when there is no load on the swing pump, the pump absorption torque becomes the same as the standard mode or light load mode.

• When the swing (blade) is operated and load is brought to bear on the swing pump, pressure signal Pa3 is input to the Pa3 port and piston (8) moves to the left ( ) according to the size of signal pressure Pa3.

• As a result, springs (5) and (7) are compressed and the spring load is increased, so the absorption torque is reduced to match the size of the swing pump load.

For machines equipped with a blade, the same pump is used for blade operations as for swing operations, so when the blade is operated, the main pump is actuated in the same way as above. ➡

PC75UU-3

10-37 2

STRUCTURE AND FUNCTION

HYDRAULIC PUMP

4. Action of spring

10-38 2

PC75UU-3

STRUCTURE AND FUNCTION

• •

•

•

•

•

•

HYDRAULIC PUMP

The spring load of springs (5) and (7) in the PC valve is changed by the swash plate angle.

When servo piston (1) moves, lever (2) moves, and piston (4) moves to the right or left according to the direction of rotation of lever (2).

If piston (4) moves to the right, spring (5) and spring (7) are compressed. If it moves further to the right, spring (5) contacts seat (6), so only spring (7) functions as a spring.

In other words, the spring load is changed by piston (5) extending or compressing springs (5) and (7).

The pump absorption torque curve, which shows the relationship between pump discharge pressure PP and discharge amount Q, is a bent curve as shown in the diagram on the right because springs (5) and (7) have different spring loads.

In addition, if mode selection solenoid valve signal pressure PM is input, even if signal pressure Pa3 of the swing (blade) pump changes, springs (5) and (7) are pushed from the right through piston (8), so the spring load changes.

The position where piston (8) stops, in other words, the pump absorption torque, is determined by the position where the force of springs (5) and (7) is in balance with pump pressure PP + mode selection pressure PM + signal pressure Pa3 of the swing (blade) pump acting on piston (8).

In other words, if pump discharge pressure PP increases, pump discharge amount Q is reduced; and if pump discharge pressure PP goes down, pump discharge amount Q is increased.

The pump absorption torque, which shows the relationship between pump discharge pressure PP and pump discharge amount Q, moves in parallel from a to b as shown in the diagram on the right according to the increase in each signal pressure.

PC75UU-3

10-39 2

STRUCTURE AND FUNCTION

HYDRAULIC PUMP

3. Pump for swing, blade SAR(2)32 Serial No.: 15001 – 19000 SAR(2)27 Serial No.: 19001 and up

a. Suction port b. Discharge port

10-40 2

1.

2.

3.

4.

5.

Cover Drive gear Driven gear Housing Bracket

Specifications Pump Type

SAR(2)32

SAR(2)27

Theoretical discharge amount

32.0 cm3/rev

26.8 cm3/rev

Set pressure

21.6 MPa {220 kg/cm2}

PC75UU-3

STRUCTURE AND FUNCTION

CONTROL VALVE

CONTROL VALVE OUTLINE The following two types of control valve are used.

• 8-spool valve (no service valve) • 9-spool valve (8-spool valve + service valve) ¡ Each service valve is an add-on type where one valve each can be added, so it is possible to add valves or remove valves if necessary.

Only an explanation of the 8-spool valve is given for the external appearance and cross section.

A1 A2 A3 A4 A5 A6 A7 A8 B1 B2 B3 B4 B5 B6 B7 B8 LS P1 P2 PA1 PB1 PA2 PB2 PA3 PB3 PA4 PB4 PA5 PB5 PA6 PB6 PA7 PB7 PA8 PB8 PS

: To swing motor MA : To blade cylinder head : To L.H. travel motor A : To R.H. travel motor A : To boom cylinder bottom : To arm cylinder head : To bucket cylinder head : To offset cylinder bottom : To swing motor MB : To blade cylinder bottom : To L.H. travel motor B : To R.H. travel motor B : To boom cylinder head : To arm cylinder bottom : To bucket cylinder bottom : To offset cylinder head : To pump LS valve : From main pump : From gear pump for swing, blade : From right swing PPC valve : From left swing PPC valve : From blade RAISE PPC valve : From blade LOWER PPC VALVE : From L.H. travel FORWARD PPC valve : From L.H. travel REVERSE PPC valve : From R.H. travel FORWARD PPC valve : From R.H. travel REVERSE PPC valve : From boom RAISE PPC valve : From boom LOWER PPC valve : From arm OUT PPC valve : From arm IN PPC valve : From bucket DUMP PPC valve : From bucket CURL PPC valve : From right offset PPC valve : From left offset PPC valve : From boom RAISE PPC valve (only during boom RAISE + swing operation) TB : To tank TC : To oil cooler TS : To tank TSW: To swing motor

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PC75UU-3

STRUCTURE AND FUNCTION

CONTROL VALVE

8-SPOOL VALVE

PC75UU-3

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STRUCTURE AND FUNCTION

CONTROL VALVE

CROSS SECTION (1/9)

1.

2.

3.

4.

5.

6.

7.

8.

Safety-suction valve (blade head) Suction valve (L.H. travel A) Suction valve (R.H. travel A) Suction valve (boom bottom) Suction valve (arm head) Suction valve (bucket head) Suction valve (offset bottom Suction valve (offset head)

10-44 2

9. Suction valve (bucket bottom) 10. Suction valve (arm bottom) 11. Suction valve (boom head) 12. Suction valve (R.H. travel B) 13. Suction valve (L.H. travel B) 14. Suction valve (blade bottom) 15. Safety valve 16. Cooler bypass valve PC75UU-3

STRUCTURE AND FUNCTION

CONTROL VALVE

(2/9)

1.

2.

3.

4.

5.

Main relief valve Spool (swing) Spool (blade) Spool (L.H. travel) Spool (R.H. travel)

PC75UU-3

6.

7.

8.

9.

Spool (boom) Spool (arm) Spool (bucket) Spool (offset)

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STRUCTURE AND FUNCTION

CONTROL VALVE

(3/9)

1.

2.

3.

4.

5.

6.

7.

8.

9.

Spool (boom RAISE merge) Gear pump relief valve for swing, blade Pressure compensation valve F (L.H. travel) Pressure compensation valve F (R.H. travel) Pressure compensation valve F (boom) Pressure compensation valve F (arm) Pressure compensation valve F (bucket) Pressure compensation valve F (offset) Pump pressure detection plug

10-46 2

10.

11.

12.

13.

14.

15. ยก

Pressure compensation valve R (offset) Pressure compensation valve R (bucket) Pressure compensation valve R (arm) Pressure compensation valve R (boom) Pressure compensation valve R (R.H. travel) Pressure compensation valve R (L.H. travel) F: Flow control valve R: Reducing valve

PC75UU-3

STRUCTURE AND FUNCTION

CONTROL VALVE

(4/9)

1.

2.

3.

4.

Check valve (offset) Check valve (bucket) Check valve (arm) Check valve (boom)

PC75UU-3

5. Check valve (blade RAISE) 6. Load check valve (swing) 7. Check valve (blade LOWER)

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STRUCTURE AND FUNCTION

CONTROL VALVE

(5/9)

1.

2.

3.

4.

Main relief valve Safety valve Pressure release valve LS bypass plug

10-48 2

5. Pump pressure detection plug 6. Spool (boom RAISE merge) 7. Unload valve

PC75UU-3

STRUCTURE AND FUNCTION

CONTROL VALVE

(6/9)

Swing valve 1. Load check valve 2. Spool 3. Spool (boom RAISE merge)

PC75UU-3

Blade valve 4. Safety-suction valve (head) 5. Suction valve (bottom) 6. Spool 7. Gear pump relief valve for swing, blade

10-49 2

STRUCTURE AND FUNCTION

CONTROL VALVE

(7/9)

L.H., R.H. travel valve 1. Suction valve (A) 2. Suction valve (B) 3. Spool 4. Pressure compensation valve R 5. Pressure compensation valve F

10-50 2

Boom valve 6. Suction valve (bottom) 7. Suction valve (head) 8. Spool 9. Pressure compensation valve R 10. Pressure compensation valve F

PC75UU-3

STRUCTURE AND FUNCTION

CONTROL VALVE

(8/9)

Arm valve 1. Suction valve (head) 2. Suction valve (bottom) 3. Spool 4. Pressure compensation valve R 5. Pressure compensation valve F

PC75UU-3

Bucket valve 6. Suction valve (head) 7. Suction valve (bottom) 8. Spool 9. Pressure compensation valve R 10. Pressure compensation valve F

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STRUCTURE AND FUNCTION

CONTROL VALVE

(9/9)

Offset valve 1. Suction valve (head) 2. Suction valve (bottom) 3. Spool 4. Pressure compensation valve R 5. Pressure compensation valve F

10-52 2

PC75UU-3

STRUCTURE AND FUNCTION

SELF-PRESSURE REDUCING VALVE

SELF-PRESSURE REDUCING VALVE

P1 : P2 : PC : PR :

From main pump To control valve To main pump LS valve Supplies oil to electromagnetic valve, PPC valve, EPC valve, etc.

T : To hydraulic tank

10-54 2

PC75UU-3

STRUCTURE AND FUNCTION

1.

2.

3.

4.

5.

6.

7.

8.

Valve (reducing valve) Valve (sequence valve) Spring (sequence valve large) Spring (sequence valve small) Plate Screw Poppet Spring (reducing valve pilot)

PC75UU-3

SELF-PRESSURE REDUCING VALVE

9.

10.

11.

12.

13.

14.

15.

Spring (reducing valve main) Filter Spring (safety valve) Ball Seat Ball Spring

10-55 2

STRUCTURE AND FUNCTION

SELF-PRESSURE REDUCING VALVE

FUNCTION • This reduces the discharge pressure of the main pump and supplies it as the control pressure of the electromagnetic valves and PPC valves.

OPERATION 1. Engine stopped • Poppet (7) is pushed against the seat by spring (8): Pr → T closed • Valve (1) is pushed against the plug by spring (9): P1 → Pr open • Valve (2) is pushed by spring (3) and spring (4): P1 → P2 closed 2. 1 At HOLD 2 When load (pressure P2) is low (operations where work equipment moves under own weight, such as jib LOWER) Note: When pressure P2 (load pressure) is lower than self-pressure reducing valve output pressure (pressure Pr) Valve (2) is subjected to force from spring (3), spring (4), and pressure Pr (0 kg/cm3 when engine is stopped) in the direction to close the circuit between port P1 → P2. However, if hydraulic oil flows in from port P1 (pressure P1), (force of spring (3) and spring (4) + area ø d of valve (2) x pressure Pr) are balanced, and the opening between P1 and P2 is adjusted in order to maintain pressure P1 at the above set value for pressure Pr. • If pressure Pr goes above the set pressure, poppet (7) opens and hydraulic oil flows from port Pr → spool (1) hole → poppet (7) opening → tank T circuit.

As a result, a difference in pressure is generated on both sides of spool (1) hole, so spool (1) moves in the direction to close the opening between P1 → Pr, and pressure Pr is maintained at the certain pressure by which pressure P1 is reduced (set pressure) by the amount of this opening.

10-56 2

PC75UU-3

STRUCTURE AND FUNCTION

SELF-PRESSURE REDUCING VALVE

3. When load pressure (pressure P2) is high When load pressure (pressure P2) is increased and pump discharge amount is increased by operation such as lifting Pressure P1 also increases (pressure P1) → (spring (3) and area d of valve (2) × pressure Pr), and valve (2) moves to the end of its stroke.

As a result, the amount of opening between P1 → P2 increases, so the passage resistance becomes smaller and the horsepower loss of the engine is reduced.

•

If pressure Pr goes above the set pressure, poppet (7) opens and hydraulic oil flows from port Pr → spool (1) hole → poppet (7) opening → tank T circuit.

As a result, a difference in pressure is generated on both sides of spool (1) hole, so spool (1) moves in the direction to close the opening between P1 → Pr. Pressure Pr is maintained at the certain pressure by which pressure P1 is reduced (set pres-sure) by the amount of this opening.

4. When load suddenly changes When load pressure (P2 pressure) suddenly goes down from high pressure to low pressure (below set pressure of reducing valve) • Valve (2) moves from the position at high load pressure to the position at low load pressure, and adjusts the opening of P1 → P2 so that pressure P1 is kept at a certain value above pressure Pr. However, to reduce the time taken to move, the check valve (consisting of seat (3), ball (13) and spring (14)) opens and supplies a large flow of oil.

• When valve (2) is at the low-load condition, and valve (2) moves in the direction to open P1 → P2, check valve parts (12), (13), and (14) close, so the flow of the hydraulic oil passes only through the orifice. This makes the movement of valve (2) slower and prevents pulsing of the pump pressure.

5. When abnormally high pressure is generated If pressure Pr of the self-pressure reducing valve becomes abnormally high, ball (11) pushes against the force of spring (10) and separates from the seat. Hydraulic oil flows from output port Pr → T, and pressure Pr is lowered to protect the equipment (PPC valve, electromagnetic valve, and other equipment using the pressure oil from port Pr) from abnormal high pressure.

PC75UU-3

10-57 2

STRUCTURE AND FUNCTION

CLSS

CLSS OUTLINE OF CLSS Features CLSS stands for Closed center Load Sensing System, and has the following features.

• Fine control not influenced by load • Control enabling digging even with fine control • Ease of compound operation ensured by flow divider function using area of opening of spool during compound operations • Energy saving using variable pump control

10-58 2

Structure • The CLSS consists of a variable capacity single piston pump, control valve, and actuators.

• The pump body consists of the main pump, PC valve and LS valve.

PC75UU-3

STRUCTURE AND FUNCTION

CLSS

BASIC PRINCIPLE 1. Control of pump swash plate angle • The pump swash plate angle (pump discharge amount) is controlled so that LS differential pressure »PLS (the difference between pump (discharge) pressure PP and control valve outlet port LS pressure PLS) (load pressure of actuator) is constant.

(LS pressure »PLS = Pump discharge pressure PP – LS pressure PLS)

If LS differential pressure »PLS becomes lower than the set pressure of the LS valve (when the actuator load pressure is high), the pump swash plate moves towards the maximum position; if the set pressure becomes higher than the set pressure of the LS valve (when the actuator load pressure is low), the pump swash plate moves towards the minimum position . ¡ For details of the operation, see HYDRAULIC PUMP. •

PC75UU-3

10-59 2

STRUCTURE AND FUNCTION

2. Pressure compensation control • A pressure compensation valve is installed to the inlet port side of the control valve spool to balance the load.

When two actuators are operated together, this valve acts to make pressure difference ÂťP

10-60 2

CLSS

between the upstream (inlet port) and downstream (outlet port) the same, regardless of the size of the load (pressure). In this way, the flow of oil from the pump is divided (compensated) in proportion to the area of openings S1 and S2 of each valve when it is operated.

PC75UU-3

STRUCTURE AND FUNCTION

CLSS

OPERATION FOR EACH FUNCTION AND VALVE Hydraulic circuit diagram and name of valves

PC75UU-3

1. Unload valve (LS pressure + 2.6 MPa {27 kg/cm2}) 2. Safety valve (27 MPa {275 kg/cm2}) 3. Pressure compensation valve 4. Suction valve 5. Safety-suction valve (12.7 MPa {130 kg/cm2}) 6. Main relief valve (24.5 MPa {260 kg/cm2}) 7. Relief valve for swing, blade (21.1 MPa {215 kg/cm2}) 8. Cooler bypass valve (cracking pressure: 0.81 MPa {8.3 kg/cm2}) 9. Boom RAISE boost merge valve

10-61 2

STRUCTURE AND FUNCTION

CLSS

UNLOAD VALVE 1. When control valve is at HOLD Function 1. When the control valve is at HOLD, pump discharge amount Q discharged by the minimum swash plate angle is released to the tank circuit.

Operation • Pump discharge pressure PP is acting on the left end of spool (1) and LS pressure PLS is acting on the right end.

• When the control valve is at HOLD, LS pressure PLS is not generated, so only pump discharge pressure PP has any effect, and PP is set only by the load of spring (2).

• As pump discharge pressure PP rises and reaches the load of spring (2) (2.6 MPa {27 kg/ cm2}), spool (1) is moved to the right (➡). The oil in the pump circuit is then connected to tank circuit T through the drill hole in sleeve (3).

10-62 2

When this happens, pump discharge pressure PP is set at 2.6 MPa {27 kg/cm2} by spring (2) inside the valve. (LS pressure PLS: 0 MPa {0 kg/cm2})

•

In this way, pump discharge pressure PP is set to 2.6 MPa {27 kg/cm2}.

PC75UU-3

STRUCTURE AND FUNCTION

2. During fine control of control valve Function • During fine control of the control valve, when the demand flow for the actuator is within the amount discharged by the minimum swash plate angle of the pump, pump discharge pressure PP is set to LS pressure PLS + 2.6 MPa {27 kg/cm2}.

Operation • When fine control is carried out on the control valve, LS pressure PLS is generated and acts on the right end of spool (1).

When this happens, the area of the opening of the control valve spool is small, so there is a big difference between LS pressure PLS and pump discharge pressure PP. • When the difference in pressure between pump discharge pressure PP and LS pressure PLS reaches the load of spring (2) (2.6 MPa {27 kg/cm2}), spool (1) moves to the right (➡), and pump circuit PP and tank circuit T are connected.

PC75UU-3

CLSS

•

When the difference in pressure between pump discharge pressure PP and LS pressure PLS reaches the load of spring (2) (2.6 MPa {27 kg/cm2}), the unload valve opens, so LS differential pressure »PLS becomes 2.6 MPa {27 kg/cm2}.

•

In other words, pump discharge pressure PP is set to a pressure equal to the spring force (2.6 MPa {27 kg/cm2}). + LS pressure PLS, and LS differential pressure »PLS becomes 2.6 MPa {27 kg/cm2}.

10-63 2

STRUCTURE AND FUNCTION

CLSS

3. Control valve operated Function • When the control valve is being operated and the demand flow for the actuator becomes greater than the pump discharge from the minimum swash plate angle, the flow of the

Operation • When the control valve is operated to a larger stroke, LS pressure PLS is generated and acts on the right end of spool (1).

When this happens, the area of the opening of the control valve spool is large, so the difference between LS pressure PLS and pump discharge pressure PP is small.

• For this reason, the difference in pressure between pump discharge pressure PP and LS pressure PLS does not reach the load of spring (2) (2.6 MPa {27 kg/cm2}), so spool (1) is pushed to the left ( ) by spring (2).

oil out to tank circuit T is cut off, and all the pump discharge amount Q flows to the actuator circuit.

•

As a result, pump circuit PP and tank circuit T are shut off, and all the pump discharge amount Q flows to the actuator circuit.

•

As a result, pump circuit PP and tank circuit T are shut off, and all the pump discharge amount Q flows to the actuator circuit.

➡

10-64 2

PC75UU-3

STRUCTURE AND FUNCTION

CLSS

INTRODUCTION OF LS PRESSURE 1. Main control valve (boom, arm, bucket, offset) Function • The LS pressure is the actuator load pressure at the outlet port end of the control valve.

• With the control valve, it reduces pump pressure PP at reducing valve (3) of the pressure compensation valve to the same pressure as actuator circuit pressure A, and sends it to the LS circuit PLS.

Operation • When spool (1) is operated, pump pressure PP flows from flow control valve (2) and notch a in the spool through bridge passage b to actuator circuit A. • At the same time, reducing valve (3) also moves to the right (➡), so pump pressure PP brought from orifice c has its pressure reduced by the pressure loss at notch d. It goes to LS circuit PLS, and then goes to spring chamber PLS1.

• When this happens, LS circuit PLS is connected to tank circuit T from LS bypass plug (4) (see the section on the LS bypass plug).

PC75UU-3

•

•

•

In addition, orifice C is installed midway between pump circuit PP and reducing valve (3), and it acts as a damper.

With the travel valve, actuator circuit pressure A is taken directly to the LS circuit PLS.

The area at both ends of reducing valve (3) is the same (SA = SLS), and actuator circuit pressure PA (=A) acts on the SA end. The reduced pump pressure PP acts on SLS at the other end.

As a result, reducing valve (3) is balanced at a position where actuator circuit pressure PA and the pressure of spring chamber PLS1 are the same. Pump pressure PP reduced at notch d becomes actuator circuit pressure A and is taken to LS circuit PLS.

10-65 2

STRUCTURE AND FUNCTION

CLSS

2. Travel valve

Operation • When spool (1) is operated, pump pressure PP flows from flow control valve (2) and notch a in the spool through bridge passage b to actuator circuit A. • At the same time, reducing valve (3) is moved to the right (➡) by actuator circuit pressure PA, and notch c and notch d are interconnected respectively with travel junction circuit e and LS circuit PLS. • As a result, actuator circuit pressure PA (= A) passes from notch c through notch d and goes to LS circuit PLS.

10-66 2

¡ The travel circuit is different from the work equipment circuit: actuator circuit pressure PA goes directly to LS circuit PLS.

PC75UU-3

STRUCTURE AND FUNCTION

LS BYPASS PLUG Function • This releases the residual pressure of LS pressure PLS. • This makes the speed of the rise in pressure of LS pressure PLS more gentle.

In addition, with this discarded throttled flow,

CLSS

it creates a pressure loss in the throttled flow of the spool or shuttle valve, and increases the stability by lowering the effective LS differential pressure.

Operation • The pressurized oil for LS circuit PLS passes from clearance filter a (formed by the clearance between LS bypass plug (1) and the valve body) through orifice b and flows to the tank circuit.

PC75UU-3

10-67 2

STRUCTURE AND FUNCTION

CLSS

PRESSURE COMPENSATION VALVE Function • During compound operations, if the load pressure becomes lower than the other actuator and the oil flow is about to increase, compensation is received.

Operation • If the load pressure of the other actuator (right side) becomes higher during compound operations, the oil flow in actuator circuit A on this side (left side) tries to increase.

• If this happens, the LS pressure PLS of the other actuator acts on spring chamber PLS1, and reducing valve (1) and flow control valve (2) are pushed to the left ( ).

• Flow control valve (2) throttles the area of opening between pump circuit PP and spool upstream PPA, and pressure loss is generated between PP and PPA. • Flow control valve (2) and reducing valve (1) ➡

10-68 2

(When this happens, the other actuator being used for compound operation (right side) is at a higher load than the actuator on this side (left side).)

•

are balanced in position where the difference in pressure between PLS and PA acting on both ends of reducing valve (2) and the pressure loss between PP and PPA on both sides of flow control valve (2) are the same.

In this way, the pressure difference between upstream pressure PPA and downstream pressure PA of both spools used during compound operations is the same, so the pump flow is divided in proportion to the area of opening of notch a of each spool.

PC75UU-3

STRUCTURE AND FUNCTION

CLSS

AREA RATIO OF PRESSURE COMPENSATION VALVE Function • The pressure compensation valve determines the compensation characteristics by carrying out fine adjustment of the area ratio (S2/S1) between area S2 of reducing valve (1) and area S1 of flow compensation valve (2) to match the characteristics of each actuator.

Area ratio (S1 : S2) and compensation characteristics • When ratio is 1.00: [pump pressure PP – spool notch upstream • pressure PPB] = • [LS circuit pressure PLS – actuator circuit pressure PA (= A)] and oil flow is divided in proportion to area of opening of spool.

• When ratio is more than 1.00: PP – PPB > PLS – PA (= A) and oil flow is divided in a proportion less than area of opening of spool.

PC75UU-3

 S1: Area of flow control valve (2)  – area of piston (3)  S2: Area of reducing valve (1)  – area of piston (3) 

•

    

When ratio is less than 1.00: PP – PPB < PLS – PA (= A) and oil flow is divided in a proportion more than area of opening of spool.

10-69 2

STRUCTURE AND FUNCTION

CLSS

L.H., R.H. TRAVEL JUNCTION CIRCUIT 1. When traveling in a straight line Function • To compensate for any difference in the oil flow in the left and right travel circuits when traveling in a straight line, the junction circuit opens when the left and right travel spools are operated.

In this way, the flow of oil to the left and right travel motors is almost the same when trav-

•

eling in a straight line, so there is no travel deviation.

When steering the machine, the difference in the load pressure returns the reducing valve of the travel valve on the inside of the turn, so the junction circuit is closed and the machine can be steered.

Operation • When left and right travel spools (1) are operated, the pump discharge flows from pump circuit PP and circuit PA to actuator circuit A. • When traveling in a straight line, to make actuator circuit PA equal, left and right reducing valves (2) are pushed to the right (➡) by the same amount, and notch a and the travel junction circuit are opened.

• In this way, the left and right travel actuator circuits are interconnected by the travel junction circuit, so if any difference occurs in the flow of oil to the left and right travel motors, the difference is compensated to prevent any deviation in travel.

10-70 2

PC75UU-3

STRUCTURE AND FUNCTION

CLSS

2. Steering when traveling

Operation • When traveling in a straight line, if left travel spool (left 1) is returned to the neutral position and the steering is operated, a difference (right A > left A) is generated in the load pressure of left and right travel actuator circuits PA, and LS pressure PLS becomes the same pressure as right A (the side with the high load pressure).

• As a result, flow control valve (3) on the left travel side is pushed to the left ( ) by LS circuit PLS, that is, right travel load pressure right A, so the opening of the left notch a is closed, the left and right travel circuits are shut off, and it becomes possible to operate the steering when traveling.

•

Damper b is provided in the circuit to dampen any excessive characteristics in the opening or closing of the travel junction circuit if the spool is operated suddenly.

➡

PC75UU-3

10-71 2

STRUCTURE AND FUNCTION

CLSS

TRAVEL LS BYPASS CIRCUIT 1. Normal operation Function • When the travel and another actuator are operated at the same time, the amount of oil discarded by the throttle in LS circuit PLS increases and the pressure compensation precision of the travel circuit is relaxed to keep

•

the drop in the travel speed to the minimum.

When the travel is operated independently or any other actuator is operated independently, the bypass circuit is closed.

Operation • When boom spool (1) is operated, LS circuit PLS becomes the same pressure as boom circuit pressure A1.

• At the same time, LS circuit pressure PLS also goes to spring chamber PLS1 of reducing valve (2) of the travel valve.

• The travel spool is not being operated, so travel actuator circuit PA is closed, and check valve (4) inside reducing valve (4) is also closed.

• As a result, when the boom is operated independently, the travel LS bypass circuit is closed.

10-72 2

PC75UU-3

STRUCTURE AND FUNCTION

CLSS

2. Travel + other actuator operated

Operation • When boom spool (1) is operated, LS circuit PLS becomes the same pressure as boom circuit pressure A1.

• With the actuator circuit pressure, the boom RAISE pressure is normally higher than the travel pressure (A1 > A2), so the pressure of spring chamber PLS1 inside reducing valve (2) of the travel valve is higher than travel circuit pressure PA. • As a result, reducing valve (2) moves to the left, LS pressure of spring chamber PLS1 goes from orifice a and pushes check valve (4) open, so oil flows from passage b and passage c to travel circuit PA.

PC75UU-3

•

For this reason, LS circuit pressure PLS (which is the same pressure as boom circuit pressure A1), flows to travel circuit A2 to reduce the pressure.

10-73 2

STRUCTURE AND FUNCTION

BOOM, ARM REGENERATION CIRCUIT Function (of boom) • When the boom is being lowered, if bottom pressure A of cylinder (1) is higher than head pressure B, and there is hydraulic drift, this

CLSS

sends the return oil flow at the bottom end to the head end to increase the cylinder speed by that amount.

Operation • If there is hydraulic drift when lowering the boom, pressure A at the bottom end of boom cylinder (1) becomes higher than pressure B at the head end.

• When this happens, part of the return oil at the bottom end passes through regeneration passage a of boom spool (1), pushes check valve (3) open, and flows to the head end.

• As a result, the boom lowering speed is increased.

10-74 2

PC75UU-3

STRUCTURE AND FUNCTION

Function • When lowering the boom, if head pressure B of cylinder (1) is greater than bottom pressure A, and the work equipment is in the load pro-

CLSS

cess, check valve (3) closes and shuts off the circuit between the head and bottom ends.

Operation • When the boom is lowered, if the work equipment is in the load process, pressure B at the head end of boom cylinder (1) becomes higher than pressure A at the bottom end.

• When this happens, check valve (3) is closed by spring (4) and pressure B at the head end, so the circuit between the head circuit and bottom circuit is shut off.

PC75UU-3

10-75 2

STRUCTURE AND FUNCTION

SWING MOTOR

SWING MOTOR LMF40AL-2 Serial No.: 15001 â&#x20AC;&#x201C; 17263

B : From swing brake solenoid valve MA : From swing control valve MB : From swing control valve S : From tank T : To tank

10-76 2

Specifications Model : LMF40AL-2 Motor capacity : 40.8 cc/rev Safety valve set pressure : 22.8 MPa {232 kg/cm2} Check valve cracking pressure : Max. 0.03 MPa {0.3 kg/cm2}

PC75UU-3

STRUCTURE AND FUNCTION

1.

2.

3.

4.

5.

6.

7.

8.

Output shaft Case Thrust plate Shoe Piston Cylinder block Valve plate End cover

PC75UU-3

SWING MOTOR

9.

10.

11.

12.

13.

14.

15.

16.

Brake spring Brake piston Plate Disc Center spring Check valve spring Check valve Relief valve

10-77 2

STRUCTURE AND FUNCTION

SWING MOTOR

LMF40AL-2 (without reverse rotation prevention valve) Serial No.: 17264 and up

B : From swing brake solenoid valve MA : From swing control valve MB : From swing control valve S : From tank T : To tank

Specifications Model : LMF40AL-2 Motor capacity : 40.8 cc/rev Safety valve set pressure : 22.8 MPa {232 kg/cm2} Check valve cracking pressure : Max. 0.03 MPa {0.3 kg/cm2}

1. Plate

10-78 2

PC75UU-3

STRUCTURE AND FUNCTION

SWING MOTOR

LMF40AEL-2 (with reverse rotation prevention valve) Serial No.: 19001 and up

B : From swing brake solenoid valve MA : From swing control valve MB : From swing control valve S : From tank T : To tank

PC75UU-3

Specifications Model : LMF40AEL-2 Motor capacity : 40.8 cc/rev Safety valve set pressure : 22.8 MPa {232 kg/cm2} Check valve cracking pressure : Max. 0.03 MPa {0.3 kg/cm2}

10-79 2

STRUCTURE AND FUNCTION

SWING MOTOR

Serial No.: 17264 and up (without reverse rotation prevention valve) Serial No.: 19001 and up (with reverse rotation prevention valve) ยก The drawing shows the motor without reverse rotation prevention valve.

1.

2.

3.

4.

5.

6.

7.

8.

Output shaft Case Thrust plate Shoe Piston Cylinder block Valve plate End cover

10-80 2

9.

10.

11.

12.

13.

14.

15.

16.

Brake spring Brake piston Plate Disc Center spring Check valve spring Check valve Relief valve

PC75UU-3

STRUCTURE AND FUNCTION

SWING MOTOR

SAFETY VALVE PORTION 1. Outline The safety valve portion consists of a check valve and relief valve.

2. Function • When the swing is stopped, the output circuit of the motor is closed by the control valve, but the motor continues to rotate because of inertia. For this reason, the pressure at the output side of the motor becomes abnormally high, and this will damage the motor. To prevent this, the oil causing the abnormal hydraulic pressure is allowed to escape from the outlet port (high-pressure side) of the motor to port S, thereby preventing damage to the motor.

3. Operation 1) When starting swing • When the swing control lever is operated to left swing, the pressurized oil from the pump passes through the control valve and is supplied to port MA. Because of this, the pressure at port MA rises, starting torque is generated in the motor, and the motor starts to rotate.

The oil from the outlet port of the motor passes from port MB through the control valve and returns to the tank.

2) When stopping swing • When the swing control lever is returned to neutral, no pressurized oil is supplied from the pump to port MA. The return circuit to the tank is closed by the control valve, so the pressure of the oil from the outlet port of the motor increases at port MB. Resistance to the rotation of the motor is created, and the brake starts to take effect.

• The pressure at port MB rises to the set pressure of relief valve B, and in this way, a high braking torque acts on the motor, and the motor stops.

• When relief valve B is being actuated, the relief oil from relief valve B and the oil from port S pass through check valve CA and are supplied to port MA. This prevents cavitation from occurring at port MA.

PC75UU-3

10-81 2

STRUCTURE AND FUNCTION

SWING MOTOR

OPERATION OF MODULATING RELIEF VALVE 1. Function â&#x20AC;˘ The relief valve of this swing motor has the property of suppressing any sudden rise in the relief pressure as shown in the diagram on the right. It acts to reduce the shock when starting and stopping the swing.

2. Operation 1) When circuit pressure is P0 The safety valve is not actuated.

2) When circuit pressure suddenly rises When the circuit pressure becomes P1, oil pressure acts on the difference in area between D1 and D3 (D1 > D3) and pushes spring (4) starts to open valve (3). When this happens, pressure acts on the difference in the area between D1 and D2 (D2 > D1) and seat (1) tries to follow valve (3). However, when seat (1) moves, the oil in chamber a is compressed, and the passage to escape to port S is throttled by ball (2), so the movement of seat (1) becomes slower than the movement of valve (3).

As a result, the relief pressure gradually rises from P1 to P2 during the time that it takes seat (1) to contact sleeve (5).

10-82 2

PC75UU-3

STRUCTURE AND FUNCTION

SWING MOTOR

OPERATION OF SWING BRAKE 1) When swing brake solenoid valve is de-energized If the swing brake solenoid valve is de-energized, the flow of pressurized oil from the selfpressure reducing valve is shut off, and port B is connected to the tank circuit.

As a result, brake piston (10) is pushed down by brake spring (9), pushes disc (12) and plate (11) together, and the brake is applied.

2) When swing brake solenoid valve is energized When the swing brake solenoid valve is energized, the valve is switched, and pressurized oil from the self-pressure reducing valve enters port B and flows to brake chamber a.

The pressurized oil entering chamber a overcomes brake spring (9) and pushes brake piston (10) up. As a result, disc (12) and plate (11) are separated and the brake is released.

PC75UU-3

10-83 2

STRUCTURE AND FUNCTION

SWING MOTOR

REVERS ROTATION PREVENTION VALVE Serial No.: 19001 and up

MA : Port MB : Port T1 : Port T2 : Port

10-84 2

1.

2.

3.

4.

5.

6.

7.

Valve body Spool (MA end) Spring (MA end) Plug (MA end) Spool (MB end) Spring (MB end) Plug (MB end)

PC75UU-3

STRUCTURE AND FUNCTION

SWING MOTOR

EFFECT EXPLANATION DRAWING

PC75UU-3

10-85 2

STRUCTURE AND FUNCTION

SWING MOTOR

Function • This valve reduces the swing back generated in the swing body by the inertia of the swing body, the backlash and rigidity of the machinery system, and the compression of the hydraulic oil when the swing is stopped.

• This is effective in preventing spillage of the load when stopping the swing and reducing the cycle time (the positioning ability is good and it is possible to move swiftly to the next job).

1. When brake pressure is being generated at port MB Operation • Pressure MB passes through the notch and goes to chamber d, spool (5) compresses spring (6) according to the difference in area D1 > D2, moves to the left, and MB → e is connected.

• When this happens, pressure MA is below the set pressure of spring (3), so spool (2) does not move. For this reason, the pressure oil is closed, and the braking force is ensured.

2. After motor stops Operation • The motor is reversed by the closing pressure generated at port MB. (1st reversal) • When this happens, reversal pressure is generated at port MA. Pressure MA goes to chamber a, compresses spring (3), spool (2) moves to the right, and MA → b is connected.

• At the same time, b → f is connected through the drill hole in spool (5), so the reversal pressure at port MA is bypassed to port T to prevent the 2nd reversal.

10-86 2

PC75UU-3

STRUCTURE AND FUNCTION

CENTER SWIVEL JOINT

CENTER SWIVEL JOINT Serial No. : 15001 â&#x20AC;&#x201C; 19000

A1. From R.H. travel control valve port A4 A2. To R.H. travel motor port B B1. From R.H. travel control valve port B4 B2. R.H. travel motor port A C1. From L.H. travel control valve port A3 C2. To L.H. travel motor port A D1. From L.H. travel control valve port B3 D2. To L.H. travel motor port B

PC75UU-3

E1. From blade control valve port A2 E2. To blade cylinder head F1. From blade control valve port B2 F2. To blade cylinder bottom G1. From travel speed solenoid valve G2. To L.H. and R.H. travel motor port D T1. To tank T2. To L.H. and R.H. travel

1.

2.

3.

4.

5.

Cover Body Slipper seal O-ring Shaft

10-87 2

STRUCTURE AND FUNCTION

CENTER SWIVEL JOINT

Serial No. : 19001 and up

A1. From R.H. travel control valve port A4 A2. To R.H. travel motor port B B1. From R.H. travel control valve port B4 B2. R.H. travel motor port A C1. From L.H. travel control valve port A3 C2. To L.H. travel motor port A D1. From L.H. travel control valve port B3 D2. To L.H. travel motor port B

10-88 2

E1. From blade control valve port A2 E2. To blade cylinder head F1. From blade control valve port B2 F2. To blade cylinder bottom G1. From travel speed solenoid valve G2. To L.H. and R.H. travel motor port D T1. To tank T2. To L.H. and R.H. travel

1.

2.

3.

4.

5.

Cover Body Slipper seal O-ring Shaft

PC75UU-3 3

STRUCTURE AND FUNCTION

CENTER SWIVEL JOINT

Serial No.: 15001 â&#x20AC;&#x201C; 19000 (option for bladeless specification)

A1.

A2.

B1.

B2.

C1.

C2.

From main control valve port A2 To L.H. travel motor port A From main control valve port B2 To L.H. travel motor port B From main control valve port B3 To R.H. travel motor port A

PC75UU-3

D1. From main control valve port A3 D2. To R.H. travel motor port B G1. From travel speed solenoid valve G2. To L.H. and R.H. travel motor port D T1. To tank T2. To L.H. and R.H. travel motor port C

1.

2.

3.

4.

5.

Cover Body Slipper seal O-ring Shaft

10-89 2

STRUCTURE AND FUNCTION

CENTER SWIVEL JOINT

Serial No.: 19001 and up (option for bladeless specification)

A1. From main control valve port A2 A2. To L.H. travel motor port A B1. From main control valve port B2 B2. To L.H. travel motor port B C1. From main control valve port B3 C2. To R.H. travel motor port A D1. From main control valve port A3 D2. To R.H. travel motor port B G1. From travel speed solenoid valve G2. To L.H. and R.H. travel motor port D DR1. To tank DR2. To L.H. and R.H. travel motor port C

10-90 2

1.

2.

3.

4.

5.

Cover Body Slipper seal O-ring Shaft

PC75UU-3

STRUCTURE AND FUNCTION

TRAVEL MOTOR

TRAVEL MOTOR

a. b. c. d. e.

Port C1 (to tank) Port A (from control valve) Port D (from travel speed solenoid valve) Port B (from control valve) Port C2 (to tank)

Specifications Model : GM09VL2 Hydraulic motor Motor capacity : Lo 39.8 cc/rev Hi 25.1 cc/rev Rated speed : Lo 1,945 rpm Hi 2,758 rpm Brake release pressure : 0.45 MPa {4.6 kg/cm2} Travel speed switching pressure : 1.96 – 6.86 MPa {20 – 70 kg/cm2} Final drive Reduction ratio : 62.4 Speed : Lo 31.2 rpm Hi 44.2 rpm

10-92 2

PC75UU-3

TRAVEL MOTOR

STRUCTURE AND FUNCTION

1.

2.

3.

4.

5.

6.

7.

8.

9.

10.

Check valve Check valve spring Counterbalance valve Return spring End cap Spring Regulator valve Brake piston Plate Disc

PC75UU-3

11.

12.

13.

14.

15.

16.

17.

18.

19.

20.

Swash plate Floating seal RV gear RV gear Crankshaft Driven gear Cover Drive gear Shaft Coupling

21.

22.

23.

24.

25.

26.

27.

28.

29.

30.

Drain plug Center shaft Regulator piston Case Spindle Piston Cylinder Brake spring Valve plate Check valve

10-93 2

STRUCTURE AND FUNCTION

TRAVEL MOTOR

OPERATION OF MOTOR 1. At low speed (motor swash plate angle at maximum)

•

•

The travel speed solenoid valve is deenergized, so the pilot pressure oil from the self-pressure reducing valve does not flow to port D. For this reason, regulator valve (6) is pushed fully to the left ( ) by spring (7).

Because of this, it pushes check valve (32), and the main pressure oil from the control valve going to end cover (5) is shut off by regulator valve (6).

At the same time, the pressurized oil in chamber a of regulator piston (23) passes through passage b in regulator valve (6) and is drained to the motor case.

•

As a result, swash plate (11) is pushed in the maximum swash plate angle direction by the main pressure inside cylinder chamber P, the motor capacity becomes the maximum, and the system is set to low speed.

➡

•

•

10-94 2

PC75UU-3

STRUCTURE AND FUNCTION

TRAVEL MOTOR

2. At high speed (motor swash plate angle at minimum)

•

•

When the travel speed solenoid valve is energized, the pilot pressure oil from the self- pressure reducing valve flows to port D, and pushes regulator valve (6) to the right (➡).

Because of this, the main pressure oil from the control valve passes through passage c in regulator valve (6), enters chamber a in regulator piston (23), and pushes regulator piston (23) to the left ( ).

As a result, swash plate (11) is pushed in the minimum swash plate angle direction, the motor capacity becomes the minimum, and the system is set to high speed. ➡

•

PC75UU-3

10-95 2

STRUCTURE AND FUNCTION

TRAVEL MOTOR

OPERATION OF PARKING BRAKE 1. When starting to travel • When the travel lever is operated, the pressurized oil from the pump actuates counterbalance valve spool (3), opens the circuit to the parking brake, pushes open check valve (31), and flows into chamber a of brake piston (8).

• It overcomes the force of spring (28), and pushes piston (8) to the left ( ).

• When this happens, the force pushing plate (26) and disc (27) together is lost, so plate (26) and disc (27) separate and the brake is released. ➡

2. When stopping travel • When the travel lever is placed in hold, counterbalance valve spool (3) returns to the neutral position and the circuit to the parking brake is closed.

• The pressurized oil in chamber a of brake piston (8) is drained to the case from the orifice in check valve (31), and brake piston (8) is pushed fully to the right (➡) by spring (28).

• As a result, plate (26) and disc (27) are pushed together, and the brake is applied.

10-96 2

PC75UU-3

STRUCTURE AND FUNCTION

TRAVEL MOTOR

OPERATION OF BRAKE VALVE Function • When traveling downhill, the weight of the machine makes it try to travel faster than the speed of the motor.

• As a result, if the machine travels with the engine at low speed, the motor will rotate without load and there is danger that the machine will run away.

• To prevent this, this valve acts to make the machine travel according to the engine speed (pump discharge amount).

Operation when pressure oil is supplied • When the travel lever is operated, the pressurized oil from the control valve is supplied to port PA. It pushes open check valve (2a) and flows from motor inlet port MA to motor outlet port MB. • However, the motor outlet port is closed by check valve (2b) and spool (3), so the pressure at the supply side rises. (Fig. 1) • The pressurized oil at the supply side flows from orifice E1 in spool (3) to chamber S1.

When the pressure in chamber S1 goes above the spool switching pressure, spool (19) is pushed to the right ( ➡ ). (Fig. 2) • As a result, port MB and port PB are connected, the outlet port side of the motor is opened, and the motor starts to rotate.

Operation of brake when traveling downhill • If the machine tries to run away when traveling downhill, the motor will turn under no load, so the pressure at the motor inlet port will drop, and the pressure in chamber S1 through orifice E1 will also drop.

• When the pressure in chamber S1 drops below the spool switching pressure, spool (3) is returned to the left ( ) by spring (4), and outlet port MB is throttled. (Fig. 3) • As a result, the pressure at the outlet port side rises, resistance is generated to the rotation of the motor, and this prevents the machine from running away.

In other words, spool (3) moves to a position where the pressure at outlet port MB balances the pressure at the inlet port and the force generated by the weight of the machine. It throttles the outlet port circuit and controls the travel speed according to the amount of oil discharged from the pump. ➡

PC75UU-3

10-97 2

STRUCTURE AND FUNCTION

VALVE CONTROL

VALVE CONTROL

1.

2.

3.

4.

5.

6.

7.

8.

Control valve R.H. work equipment PPC valve R.H. work equipment control lever Blade control lever Hydraulic pump Blade PPC valve L.H. work equipment control lever L.H. work equipment PPC valve

10-98 2

9.

10.

11.

12.

13.

14.

15.

16.

Travel speed boost pedal Solenoid valve assembly L.H. travel control lever Travel PPC valve Solenoid, EPC valve assembly R.H. travel control lever Offset PPC valve Boom offset control pedal

PC75UU-3

STRUCTURE AND FUNCTION

PPC VALVE

PPC VALVE For work equipment, swing

k1 This shows Serial No.: 16520 and up.

P : From PPC lock solenoid T : To tank P1: L.H.: Arm OUT / R.H.: Boom LOWER

PC75UU-3

P2: L.H.: Arm IN / R.H.: Boom RAISE P3: L.H.: Right swing / R.H.: Bucket CURL P4: L.H.: Left swing / R.H.: Bucket DUMP

10-99 2

STRUCTURE AND FUNCTION

1.

2.

3.

4.

5.

6.

Spool Metering spring Centering spring Piston Disc Nut (for connecting lever)

PC75UU-3

PPC VALVE

7.

8.

9.

10.

11.

Joint Plate Retainer Body Filter

10-101 2

STRUCTURE AND FUNCTION

PPC VALVE

Operation 1) At HOLD Ports A and B of the control valve and ports P1 and P2 of the PPC valve are connected to drain chamber D through fine control hole f in spool (1). (Fig. 1)

2) Fine control (HOLD â&#x2020;&#x2019; fine control) When piston (4) starts to be pushed by disc (5), retainer (9) is pushed. Spool (1) is also pushed by metering spring (2) and moves down.

When this happens, fine control hole f is shut off from drain chamber D. At almost the same time, it is connected to pump pressure chamber PP, and the pilot pressure from port PPPC of the main valve is sent through fine control hole f and goes from port P1 to port A. When the pressure at port P1 rises, spool (1) is pushed back. Fine control hole f is shut off from pump pressure chamber PP. At almost the same time, it is connected to drain chamber D, so the pressure at port P1 escapes.

As a result, spring (1) moves up and down until the force of metering spool (2) is balanced with the pressure of port P1.

The relationship of the positions of spool (1) and body (10) (fine control hole f is in the middle between drain chamber D and pump pressure chamber PP) does not change until retainer (9) contacts spool (1).

Therefore, metering spring (2) is compressed in proportion to the travel of the control lever, so the pressure at port P1 also rises in proportion to the travel of the control lever.

In this way, the spool of the control valve moves to a position where the pressure of chamber A (same as pressure at port P1) and the force of the return spring of the control valve spool are balanced. (Fig. 2)

(Fig. 1)

(Fig. 2)

10-102 2

PC75UU-3

STRUCTURE AND FUNCTION

PPC VALVE

3) Fine control (control lever returned) When disc (5) starts to be returned, spool (1) is pushed up by the force of centering spring (3) and the pressure at port P1.

Because of this, fine control hole f is connected to drain chamber D, and the pressurized oil at port P1 is released.

If the pressure at port P1 drops too much, spool (1) is pushed down by metering spring (2), so fine control hole f is shut off from drain chamber D. At almost the same time, it is connected to pump pressure chamber PP, so the pressure at port P1 supplies the pump pressure until the pressure recovers to a pressure equivalent to the position of the lever.

When the control valve returns, oil in drain chamber D flows in from fine control hole fâ&#x20AC;&#x2122; of the valve on the side that is not moving. It passes through port P2 and goes to chamber B to charge the oil. (Fig. 3)

(Fig. 3)

4) At full stroke Disc (5) pushes down piston (4), and retainer (9) pushes down spool (1). Fine control hole f is shut off from drain chamber D and is connected to pump pressure chamber PP. Therefore, the pilot pressure oil from port PPPC of the main valve passes through fine control hole f and flows from port P1 to chamber A to push the control valve spool.

The return oil from chamber B passes from port P2 through fine control hole fâ&#x20AC;&#x2122; and flows to drain chamber D. (Fig. 4)

(Fig. 4)

PC75UU-3

10-103 2

STRUCTURE AND FUNCTION

PPC VALVE

FOR TRAVEL Serial No.: 15001 and up

P : From self-pressure reducing valve T : To tank P1 : L.H. FORWARD P2 : L.H. REVERSE P3 : R.H. FORWARD P4 : R.H. REVERSE

10-104 2

PC75UU-3

STRUCTURE AND FUNCTION

1.

2.

3.

4.

Piston Plate Collar Body

PC75UU-3

PPC VALVE

5.

6.

7.

8.

Valve Metering spring Centering spring Bolt

10-105 2

STRUCTURE AND FUNCTION

PPC VALVE

Operation 1) At HOLD Ports A and B of the control valve and ports P1 and P2 of the PPC valve are connected to drain chamber D through fine control hole f in spool (1). (Fig. 1)

2) Fine control (HOLD â&#x2020;&#x2019; fine control) When piston (4) starts to be pushed by disc (5), retainer (9) is pushed. Spool (1) is also pushed by metering spring (2) and moves down.

When this happens, fine control hole f is shut off from drain chamber D. At almost the same time, it is connected to pump pressure chamber PP, and the pilot pressure of the self pressure reducing valve is sent through fine control hole f and goes from port P1 to port A. When the pressure at port P1 rises, spool (1) is pushed back. Fine control hole f is shut off from pump pressure chamber PP. At almost the same time, it is connected to drain chamber D, so the pressure at port P1 escapes.

As a result, spool (1) moves up and down until the force of metering spring (2) is balanced with the pressure of port P1.

The relationship of the positions of spool (1) and body (10) (fine control hole f is in the middle between drain chamber D and pump pressure chamber PP) does not change until retainer (9) contacts spool (1).

Therefore, metering spring (2) is compressed in proportion to the travel of the control lever, so the pressure at port P1 also rises in proportion to the travel of the control lever.

In this way, the spool of the control valve moves to a position where the pressure of chamber A (same as pressure at port P1) and the force of the return spring of the control valve spool are balanced. (Fig. 2)

10-106 2

PC75UU-3

STRUCTURE AND FUNCTION

PPC VALVE

3) Fine control (control lever returned) When disc (5) starts to be returned, spool (1) is pushed up by the force of centering spring (3) and the pressure at port P1.

Because of this, fine control hole f is connected to drain chamber D, and the pressurized oil at port P1 is released.

If the pressure at port P1 drops too much, spool (1) is pushed down by metering spring (2), so fine control hole f is shut off from drain chamber D. At almost the same time, it is connected to pump pressure chamber PP, so the pressure at port P1 supplies the pump pressure until the pressure recovers to a pressure equivalent to the position of the lever.

When the control valve returns, oil in drain chamber D flows in from fine control hole fâ&#x20AC;&#x2122; of the valve on the side that is not moving. It passes through port P2 and goes to chamber B to charge the oil. (Fig. 3)

4) At full stroke Disc (5) pushes down piston (4), and retainer (9) pushes down spool (1). Fine control hole f is shut off from drain chamber D and is connected to pump pressure chamber PP. Therefore, the pilot pressure oil from the self pressure reducing valve passes through fine control hole f and flows from port P1 to chamber A to push the control valve spool.

The return oil from chamber B passes from port P2 through fine control hole fâ&#x20AC;&#x2122; and flows to drain chamber D. (Fig. 4)

PC75UU-3

10-107 2

STRUCTURE AND FUNCTION

PPC VALVE

FOR BLADE, OFFSET Serial No.: 15001 and up

a b c d

: To tank : From self-pressure reducing valve : P1 port : P2 port

10-108 2

1.

2.

3.

4.

5.

6.

7.

8.

Spool Metering spring Centering spring Piston Lever Plate Retainer Body

PC75UU-3

STRUCTURE AND FUNCTION

PPC VALVE

Operation 1) At HOLD Ports A and B of the control valve and ports P1 and P2 of the PPC valve are connected to drain chamber D through fine control hole f in spool (1). (Fig. 1)

2) Fine control (HOLD â&#x2020;&#x2019; fine control) When piston (4) starts to be pushed by lever (5), retainer (7) is pushed. Spool (1) is also pushed by metering spring (2) and moves down.

When this happens, fine control hole f is shut off from drain chamber D. At almost the same time, it is connected to pump pressure chamber PP, and the pilot pressure of the self pressure reducing valve is sent through fine control hole f and goes from port P1 to port A. When the pressure at port P1 rises, spool (1) is pushed back. Fine control hole f is shut off from pump pressure chamber PP. At almost the same time, it is connected to drain chamber D, so the pressure at port P1 escapes.

As a result, spool (1) moves up and down until the force of metering spool (2) is balanced with the pressure of port P1.

The relationship of the positions of spool (1) and body (8) (fine control hole f is in the middle between drain hole D and pump pressure chamber PP) does not change until retainer (7) contacts spool (1).

Therefore, metering spring (2) is compressed in proportion to the travel of the control lever, so the pressure at port P1 also rises in proportion to the travel of the control lever.

In this way, the spool of the control valve moves to a position where the pressure of chamber A (same as pressure at port P1) and the force of the return spring of the control valve spool are balanced. (Fig. 2)

PC75UU-3

10-109 2

STRUCTURE AND FUNCTION

PPC VALVE

3) Fine control (control lever returned) When lever (5) starts to be returned, spool (1) is pushed up by the force of centering spring (3) and the pressure at port P1.

Because of this, fine control hole f is connected to drain chamber D, and the pressurized oil at port P1 is released.

If the pressure at port P1 drops too much, spool (1) is pushed down by metering spring (2), so fine control hole f is shut off from drain chamber D. At almost the same time, it is connected to pump pressure chamber PP, so the pressure at port P1 supplies the pump pressure until the pressure recovers to a pressure equivalent to the position of the lever.

When the control valve returns, oil in drain chamber D flows in from fine control hole fâ&#x20AC;&#x2122; of the valve on the side that is not moving. It passes through port P2 and goes to chamber B to charge the oil. (Fig. 3)

4) At full stroke Lever (5) pushes down piston (4), and retainer (7) pushes down spool (1). Fine control hole f is shut off from drain chamber D, and is connected to pump pressure chamber PP. Therefore, the pilot pressure oil from the self pressure reducing valve passes through fine control hole f and flows from port P1 to chamber A to push the control valve spool.

The return oil from chamber B passes from port P2 through fine control hole fâ&#x20AC;&#x2122; and flows to drain chamber D. (Fig. 4)

10-110 2

PC75UU-3

STRUCTURE AND FUNCTION

SOLENOID VALVE

SOLENOID VALVE For PPC lock, swing brake, travel speed, mode selection

a. b. c. d. e. f. g. h.

Port Port Port Port Port Port Port Port

T (to tank) P (from self-pressure reducing valve) T1 (from PPC valve) T2 (to boom RAISE merge valve) A1 (to PPC valve) A2 (to swing motor) A3 (to L.H., R.H. travel motor) A4 (to pump PC valve)

PC75UU-3

1.

2.

3.

4.

5.

PPC safety lock solenoid valve Swing brake solenoid valve Travel speed solenoid valve Mode selection solenoid valve Block

10-111 2

STRUCTURE AND FUNCTION

SOLENOID VALVE

1.

2.

3.

4.

5.

6.

7.

8.

Nut Plunger Coil Connector Push pin Spring Spool Block

Operation When solenoid is de-energized • The signal current does not flow from the controller, so coil (3) is de-energized.

• For this reason, spool (7) is pushed to the left ( ) by spring (6).

• As a result, port A closes and the pressurized oil from the control pump does not flow to the actuator.

At the same time, the oil from the actuator flows from port A to port T, and is then drained to the tank. ➡

When solenoid is energized • When the signal current flows to the solenoid valve, coil (3) is energized, and propulsion force is generated to move plunger (2) to the right (➡).

• For this reason, spool (7) is pushed to the right (➡) by push pin (5).

• As a result, the pressurized oil from the control pump flows from port A to port B, and then flows to the actuator.

At the same time, port C is closed, and this stops the oil from flowing to the tank.

10-112 2

PC75UU-3

STRUCTURE AND FUNCTION

SOLENOID VALVE, EPC VALVE

SOLENOID VALVE, EPC VALVE For boom RAISE stop, boom LOWER stop, arm IN stop, left offset stop

a. b. c. d. e. f. g. h. i.

Port A4 (from arm PPC valve (IN)) Port B4 (to arm control valve (IN)) Port A3 (from boom PPC valve (RAISE)) Port B3 (to boom IN valve (LOWER)) Port A2 (from boom PPC valve (LOWER)) Port B2 (to boom control valve (LOWER)) Port A1 (from offset PPC valve (left)) Port B1 (to offset control valve (left)) Port T (to tank)

PC75UU-3

1. Arm IN stop EPC valve 2. Boom RAISE stop EPC valve 3. Boom LOWER stop solenoid valve 4. Left offset stop solenoid valve EPC valve 5. Coil (proportional type) 6. Push pin 7. Valve spool 8. Guide 9. Return spring

Solenoid valve 10. Coil (ON-OFF type) 11. Push pin 12. Guide 13. Valve spool 14. Return spring EPC valve 15. Plug 16. O-ring 17. Ball 18. Plug 19. Spring

10-113 2

STRUCTURE AND FUNCTION

SOLENOID VALVE, EPC VALVE

Operation When solenoid is energized • When the signal current flows from the controller to solenoid (3), solenoid (3) is energized.

• For this reason, spool (13) is pushed to the left.

• As a result, the pressurized oil from the main pump flows from port P through the inside of spool (13) to port A, and then flows to the actuator.

At the same time, port T is closed, and this stops the oil from flowing to the tank.

When solenoid is de-energized • The signal current does not flow from the controller, so coil (10) is de-energized.

• For this reason, spool (13) is pushed fully to the right by spring (14).

• As a result, the circuit from port P to port A closes and the pressurized oil from the main pump does not flow to the actuator.

At the same time, the pressurized oil from the actuator flows from port A to port T, and is then drained to the tank.

10-114 2

PC75UU-3

STRUCTURE AND FUNCTION

SOLENOID VALVE, EPC VALVE

EPC VALVE 1. When signal current is maximum (coil energized, circuit pressure maximum) • When the signal current flows to coil (5), coil (5) is energized.

When this happens, the signal current is at its maximum.

• For this reason, spool (7) is pushed down fully by push pin (6).

• As a result, the flow of pressurized oil from port A flows through port B, and all flows to the control valve.

At the same time, port T closes and stops the oil from flowing to the tank.

2. When signal current is reduced (coil energized, circuit pressure reduced) • When the signal current to coil (5) is reduced, coil (5) is energized, but the propulsion force of the coil is proportionate to the signal current.

• Push pin (6) pushes spool (7) down, and pressurized oil flows from port A to port B. • When the pressure at port B rises and the force acting on surface a of spool (7) becomes greater than the propulsion force of coil (5), spool (7) is pushed up. The circuit between port A and port B is shut off, and at the same time, port A and port T are connected.

• As a result, spool (7) is moved up or down until the propulsion force of coil (5) is balanced with the pressure of port B. • Therefore, the circuit pressure between the PPC valve and the control valve is controlled in proportion to the size of the signal current.

PC75UU-3

10-115 2

STRUCTURE AND FUNCTION

SOLENOID VALVE, EPC VALVE

3. When signal current is 0 (coil de-energized, circuit shut off) • When there is no signal current flowing from the controller to coil (5), coil (5) is de-energized.

• For this reason, spool (7) is pushed up in the direction of the arrow by spring (9).

• As a result, port A closes and the pressurized oil from the PPC valve does not flow to the control valve.

At the same time, the pressurized oil from the control valve passes from port B through port T and is drained to the tank.

4. Signal current 0 → increased → maximum • It is actuated in the order 3 → 2 → 1 explained above.

10-116 2

PC75UU-3

STRUCTURE AND FUNCTION

WORK EQUIPMENT

WORK EQUIPMENT

1.

2.

3.

4.

5.

6.

Bucket Bucket cylinder Arm 3rd bracket Arm cylinder Offset cylinder

PC75UU-3

7. 2nd boom 8. Sub link 9. Boom cylinder 10. 1st boom 11. Blade cylinder 12. Front blade

10-117 2

STRUCTURE AND FUNCTION

AIR CONDITIONER PIPING

AIR CONDITIONER PIPING (OPT)

1.

2.

3.

4.

5.

6.

7.

8.

Air conditioner unit Air conditioner compressor Condenser Hot water take-off piping Receiver tank Refrigerant piping Heater Hot water return piping

PC75UU-3

A. Recirculation port B. Hot air/cold air vent C. Hot air vent

10-119 2

STRUCTURE AND FUNCTION

ELECTRIC WIRING DIAGRAM

ELECTRIC WIRING DIAGRAM

1.

2.

3.

4.

5.

6.

7.

8.

9.

10.

11.

Horn switch One-touch slow-down switch Monitor panel One-touch slow-down pilot lamp Fuel control dial Starting switch Swing brake cancel switch Fuel control motor Fuse box Cancel resistance Four system controller

PC75UU-3

12.

13.

14.

15.

16.

17.

18.

19.

20.

21.

Wiper switch (cab specification) Heater switch (cab specification) Lamp switch PPC lock switch Heater (cab specification) Travel speed boost pedal Interference prevention alarm cancel switch Deceleration controller Attachment selection connector Alarm buzzer

10-121 2

STRUCTURE AND FUNCTION

ELECTRIC WIRING DIAGRAM

22. Arm potentiometer 23. Battery 24. Battery electrolyte level sensor (Serial No.: 15001 â&#x20AC;&#x201C; 19000) 25. Fusible link 26. Offset potentiometer 27. Battery relay 28. Work lamp 29. Right swing oil pressure switch 30. Left swing oil pressure switch 31. Boom potentiometer 32. Room lamp (cab specification) 33. Coolant temperature sensor 34. Radio (cab specification) 35. Glow plug 36. Engine stop solenoid 37. Washer tank (cab specification) 38. Engine oil pressure sensor 39. Alternator 40. Starting motor 41. Wiper motor (cab specification) 42. Fuel pump 43. Fuel level sensor 44. Mode selector solenoid valve 45. Travel speed selector solenoid 46. Swing holding brake solenoid valve 47. PPC lock solenoid valve 48. Arm IN oil pressure switch 49. Arm IN stop EPC valve 50. Boom RAISE oil pressure switch 51. Boom RAISE stop EPC valve 52. Boom LOWER stop solenoid valve 53. Left offset stop solenoid valve 54. Horn

10-122 2

PC75UU-3

STRUCTURE AND FUNCTION

PC75UU-3

ELECTRIC WIRING DIAGRAM

10-123 2

STRUCTURE AND FUNCTION

ENGINE CONTROL

ENGINE CONTROL

1.

2.

3.

4.

5.

6.

Battery Battery relay Starting motor Engine stop solenoid One-touch slow-down switch Deceleration controller

10-124 2

7.

8.

9.

10.

11.

12.

Fuel control motor One-touch slow-down pilot lamp Fuel control dial Starting switch Governor lever Fuel injection pump

PC75UU-3

STRUCTURE AND FUNCTION

ENGINE CONTROL

OPERATION OF SYSTEM STARTING ENGINE

•

•

•

When the starting switch is turned to the ON position, the engine stop solenoid drives the governor lever to the RUN position. This method is provides a fail-safe structure, because if any abnormality occurs in the electrical system, the engine will stop.

When the starting switch is turned to the START position, the starting signal flows to the starting motor, and the starting motor turns to start the engine.

When this happens, the fuel control dial is interconnected with the fuel adjustment motor, so the engine speed is the speed set by the fuel control dial.

PC75UU-3

10-125 2

STRUCTURE AND FUNCTION

ENGINE CONTROL

ENGINE SPEED CONTROL

• •

The fuel control dial is interconnected with the fuel adjustment motor.

The fuel adjustment motor drives the cable so that the governor lever angle is at a position that matches the position of the fuel control dial.

10-126 2

PC75UU-3

STRUCTURE AND FUNCTION

ENGINE CONTROL

STOPPING ENGINE

â&#x20AC;¢

When the starting switch is turned to OFF, the engine stop solenoid drives the governor stop lever to the STOP position and the engine stops.

PC75UU-3

10-127 2

STRUCTURE AND FUNCTION

ENGINE CONTROL

ONE-TOUCH SLOW-DOWN

•

When the one-touch slow-down switch is pressed, the deceleration signal flows to the deceleration controller.

• The deceleration controller lights up the onetouch slow- down pilot lamp, and at the same time, drives the fuel adjustment motor to lower the engine speed to low idling.

• If the one-touch slow-down switch is pressed, it sets to low idling; if it is pressed again, the engine speed returns to the speed set by the fuel control dial. ¡ Even if the engine is stopped with the onetouch slow- down actuated, the one-touch slow-down is canceled when the engine is started again, so the engine starts at the speed condition set by the fuel control dial. ¡ When the one-touch slow-down is being actuated, even if the fuel control dial is operated, the engine speed is held at low idling.

10-128 2

PC75UU-3

STRUCTURE AND FUNCTION

ENGINE CONTROL

COMPONENTS OF SYSTEM FUEL CONTROL DIAL

1.

2.

3.

4.

5.

6.

7.

8.

One-touch slow-down pilot lamp Fuel control dial Boss Boss Shaft Joint Bracket Fuel control motor

PC75UU-3

10-129 2

STRUCTURE AND FUNCTION

ENGINE CONTROL

FUEL CONTROL MOTOR

1. Motor assembly 2. Cable 3. Connector

10-130 2

PC75UU-3

STRUCTURE AND FUNCTION

ENGINE CONTROL

DECELERATION CONTROLLER

Input/output signal M-2P (CN-K35) Pin No.

Name of signal

X-4P (CN-K5) Input/output signal

Pin No.

Name of signal

Input/output signal

1

Deceleration pilot lamp (+)

Output

1

Power source (24V)

Input

2

Deceleration pilot lamp (–)

Output

2

GND

Input

3

NC

4

One-touch slow-down switch

SWP-6P (CN-K6) Pin No.

Name of signal

Input/output signal

1

Motor (+)

Output

2

COM

Output

3

Deceleration power source

Output

4

Motor (–)

Output

5

Acceleration signal

Output

6

Deceleration signal

Output

PC75UU-3

— Input

10-131 2

STRUCTURE AND FUNCTION

FOUR SYSTEM

FOUR SYSTEM (4 SYSTEM) •

The 4-system is a 4-system structure consisting of the following: interference prevention function, depth measurement system, height/ depth automatic stop system, and offset positioning system. It excels in safety and productivity.

•

Control functions Speed reduction function

Stop, warning function 1

Emergency stop alarm function

Interference prevention function

Cancel function

Reset function

Depth below ground surface display function

2

Depth measurement system

Four system (4 system)

Depth below benchmark surface display function

Height setting function

3

Height /depth automatic stop system Depth setting function

4

Offset positioning system

Left offset setting function 5

Boom end cushion function 6

Arm end cushion function 7

Self-diagnostic function

10-132 2

PC75UU-3

STRUCTURE AND FUNCTION

â&#x20AC;¢

FOUR SYSTEM

TOTAL SYSTEM DIAGRAM

PC75UU-3

10-133 2

STRUCTURE AND FUNCTION

FOUR SYSTEM

1. INTERFERENCE PREVENTION SYSTEM • Because of the structure of the PC75UU, when left offset operations and work equipment operations are performed, there are areas at the front and right side of the cab (canopy) where the bucket and cab (canopy) may come into contact.

• With the interference prevention system, electronic control always observes the position of the bucket, and if the bucket comes close to the interference area, it automatically stops the work equipment and sounds the alarm buzzer.

• This ensures excellent safety and ease of operation in the left offset area.

•

•

•

•

The rotating angle of the boom, rotating angle of the arm, and rotating angle of the offset are detected by the output signals of the boom, arm, and offset potentiometers. The controller always uses these signals to calculate the X coordinate, Y coordinate, and Z coordinate of point A. If point A gradually comes closer to the interference area, when it enters a certain range (deceleration range), the speed of movement of the work equipment is reduced. (except offset) If point A enters the interference area, the work equipment is automatically stopped, and the buzzer sounds to prevent interference before it happens.

If any abnormality occurs in the controller or potentiometers, communications with the solenoid valves is cut off, and the work equipment is stopped, but if the cancel switch is turned ON, it is possible to operate the work equipment.

10-134 2

PC75UU-3

STRUCTURE AND FUNCTION

FOUR SYSTEM

Operation ยก The diagram is an actuation diagram, so the position of the bucket may be slightly different from the actual dimensions and position.

PC75UU-3

10-135 2

STRUCTURE AND FUNCTION

FOUR SYSTEM

1) Deceleration function • If the bucket leave the safety area and enters the deceleration range, to reduce the shock at the stopping point, the speed of the boom RAISE and arm IN is reduced so the bucket speed is reduced smoothly.

• The deceleration is carried out by the EPC valve reducing the output pressure from the PPC valve to the control valve.

• If the bucket speed is lower than the standard value, no deceleration is carried out. ¡ There is no deceleration range or function for the offset.

2) Stop, alarm function • If the bucket goes beyond the deceleration range and enters the interference area, the bucket is automatically stopped and the alarm buzzer sounds. ¡ The work equipment is stopped by the solenoid valve and EPC valve draining the output pressure from the PPC valve to the control valve to the tank. ¡ After work equipment stops, it is possible to use the operations that have not stopped to move the bucket out from the stop range and continue operations.

3) Emergency stop, alarm function • If there is a failure in the solenoid valve or EPC valve and the work equipment does not stop at the stop point, but the bucket goes closer, if it enters the emergency stop range, the safety structure stops the work equipment and swing and sounds the alarm buzzer.

• If this function is actuated, an abnormality has occurred in the equipment, so the electronic system caution lamp on the monitor panel flashes, error code [61] is displayed on the depth display to warn the operator of the abnormality.

• When stopping, the solenoid valve drains the basic pressure from the control pump to the PPC valve to the tank, so all the operations using the PPC circuit stop. ¡ To reset after this function is actuated, it is necessary to use the cancel function, so see 4) cancel function for details.

10-136 2

Operations that are stopped Alarm buzzer

Boom RAISE Arm IN Left offset Sounds slowly (once every second)

Operations that are stopped

Boom, arm, bucket, swing, offset

Alarm buzzer

Sounds rapidly (once every 0.6 seconds)

Electronic system caution lamp

Flashes rapidly (once every 0.6 seconds)

Depth indicator

Error code [61] displayed

PC75UU-3

STRUCTURE AND FUNCTION

FOUR SYSTEM

4) Cancel function • If the emergency stop function is actuated or if any abnormality occurs in the controller or potentiometers, the controller shuts off the signal current to the solenoid valves and EPC valves, and stops the actuation of the work equipment and swing.

• If this happens, inspection must be carried out immediately, but if it is necessary to move the machine temporarily to a safe place, it is possible to operate the work equipment freely by turning the cancel switch under the operator’s seat ON. • When the cancel switch is turned ON, the alarm buzzer sounds and the electronic system caution lamp flashes to inform the operator that the cancel function has been actuated.

Operations where stop is canceled

Boom, arm, bucket, swing, offset

Alarm buzzer

Sounds for 7 seconds

Electronic system caution lamp

Flashes slowly (once every second)

¡ If there is any abnormality in the solenoids or EPC electrical system, the cancel function will not work.

If the error code for [abnormality in solenoid system] is displayed on the monitor panel depth display, the cancel switch must not be turned ON. ¡ If the controller is removed and the cancel switch is turned ON, the boom RAISE and arm IN operation cannot be used. ¡ The cancel switch is an auto-return type, so it automatically returns to the OFF position when it is released.

PC75UU-3

10-137 2

STRUCTURE AND FUNCTION

5) Reset function a) Resetting input signal (potentiometer installation angle) • If the potentiometer has been replaced or the work equipment has been replaced, an error and input signal will occur because of the error in the mounting position of the potentiometer.

The reset function allows this error to be compensated at a touch without measuring the output voltage or carrying out fine adjustment of the potentiometer.

• Operate the boom RAISE, arm IN, and right offset fully then input the input reset signal.

The difference (error in the mounting position) between the angle calculated from the actual output voltage for each potentiometer and the set angle inside the computer is stored in memory as the compensation value. b) Front and rear automatic stop position reset function • If an error occurs in the automatic stop position at the front of the cab caused by the error in the work equipment dimensions used for calculating the bucket position or an error in the computer calculation, this function can be used to compensate the error at a touch.

• Set the bucket to the stop condition at the specified position and input the front and rear automatic stop position reset signals. The difference (error in the mounting position) between the position calculated from the actual output voltage for each potentiometer and the set position inside the computer is stored in memory as the compensation value. c) Left and right automatic stop position reset function • If an error occurs in the automatic stop position at the side of the cab caused by the error in the work equipment dimensions used for calculating the bucket position or an error in the computer calculation, this function can be used to compensate the error at a touch.

• This function can be used for compensating the stop position, even if buckets with different width, such as the optional narrow or wide buckets, are installed.

• Set the bucket to the stop condition at the specified position and input the left and right automatic stop position reset signals. The difference (error in the mounting position) between the position calculated from the actual output voltage for each potentiometer and the set position inside the computer is stored in memory as the compensation value.

10-138 2

FOUR SYSTEM

Example: Boom potentiometer

PC75UU-3

STRUCTURE AND FUNCTION

FOUR SYSTEM

d) Depth display reset function • If an error occurs in the depth display cab caused by the error in the work equipment dimensions used for calculating the bucket position or an error in the computer calculation, this function can be used to compensate the error at a touch.

• Set the bucket on the ground at positions A and B and input the depth display reset signals. The difference (error in the mounting position) between the depth calculated from the output voltage for each potentiometer and the actual set depth is stored in memory as the compensation value. ¡ Once the compensated value is stored in memory, it will not be deleted even if the starting switch is turned OFF. ¡ If the work equipment is in a markedly different position from the standard position when resetting with the input signal reset and output signal reset, the compensation value is taken as 0 and control is carried out without compensation.

• In such a case, the applicable error code is displayed on the depth display on the monitor panel, and the operator is recommended to carry out the resetting operation again.

• When resetting the depth display, no error code is displayed. ¡ For details of the resetting method, see TESTING AND ADJUSTING.

PC75UU-3

10-139 2

STRUCTURE AND FUNCTION

FOUR SYSTEM

2. DEPTH MEASUREMENT SYSTEM • The present digging depth and the depth desired to be measured are displayed digitally on the depth display on the monitor panel, so there is excellent productivity and ease of operation.

• The depth measurement system can be selected to display the depth from the ground level or the depth from a standard surface. ¡ When the starting switch is turned ON, the depth from the ground level is automatically displayed.

a) Depth from ground level display function • The depth from the ground level is always displayed on the depth display on the monitor panel during operation.

[Setting method] • When the starting switch is turned ON, this function automatically starts to display.

[Display method] • It displays the distance below ground level in units of 0.1 m. ¡ The value is rounded to the nearest one place of decimal.

• If the bucket is above ground level, it displays UP. ¡ The 0 point for this display is set as the position when the bucket is stood up right, so when measuring the depth, set to the same bucket posture.

If the bucket posture is different, there will be a difference between the displayed depth and the actual depth. ¡ If the system has been set to the function to display the depth from a standard surface, the function to display the depth from the ground level is automatically canceled.

10-140 2

PC75UU-3

STRUCTURE AND FUNCTION

FOUR SYSTEM

b) Depth from standard surface display function (Depth display 0 set mode) • If a desired height is set as the standard surface, the depth from that surface is always displayed on the depth display on the monitor panel during operations. ¡ If this function is set, the function for measuring the depth from the ground level is automatically canceled.

[Setting method] • Set the mode selection switch to depth display 0 set.

• Set the bucket at the position to be used as the standard surface.

• Rotate the set switch to SET and check that the depth display is [0.0.].

[Display method] • It displays the distance below the standard surface in units of 0.1 m. ¡ The value is rounded to the nearest one place of decimal.

• If the bucket is above ground level, it displays UP. [Cancel method] • Set the mode selector switch to depth display 0 set.

• Turn the set switch to CLEAR. ¡ When setting the bucket to the measurement surface, set the bucket to the same posture as when setting the standard surface.

If the bucket posture is different, there will be a difference between the displayed depth and the actual depth. ¡ If this function is canceled, the depth display will return automatically to the depth from the ground level display function.

•

Outline of depth calculation • Ya: Depth (constant) from boom foot to ground level • Yb: Depth from boom foot to desired standard surface • Yc: Depth from boom foot to measurement surface

a) Display of depth from the ground level = Yc – Ya b) Display of depth from the datum level = Yc – Yb

PC75UU-3

10-141 2

STRUCTURE AND FUNCTION

FOUR SYSTEM

3. HEIGHT, DEPTH AUTOMATIC STOP SYSTEM • If the position to stop the boom is set in advance, the boom will automatically stop at that height or depth during operation.”

This provides excellent productivity and safety when operating on jobsites where there are obstacles such as buried pipes or electric cables.

a) Height set function (height mode) • If the boom is set to the desired height, the boom will always stop at that height during operations.

• By limiting the range for boom RAISE operations, it is possible to limit the height of the work equipment. ¡ Note that this function does not limit the height of the bucket.

[Setting method] • Set the mode selector switch to [height].

• Raise the boom to the desired position.

• Turn the set switch to SET, and check that the buzzer sounds twice and the indicator lights up.

[Operation] • When the boom is lowered, it will always stop at the set position when it is raised during operations.

[Cancel method] • Turn the mode selector switch to [height].

• Turn the set switch to CLEAR and check that the indicator goes out.

• The work equipment is stopped by draining the output pressure from the boom PPC valve to the boom control valve (RAISE) at the EPC valve to the tank.

10-142 2

PC75UU-3

STRUCTURE AND FUNCTION

FOUR SYSTEM

b) Depth setting function (depth set mode) • If the boom is set to the desired depth, the boom will always stop at that depth during operations.

• By limiting the range for boom LOWER operations, it is possible to limit the digging depth. ¡ Note that this function does not limit the depth of the bucket.

[Setting method] • Set the mode selector switch to [depth].

• Lower the boom to the desired position.

• Turn the set switch to SET, and check that the buzzer sounds twice and the indicator lights up.

[Operation] • When the boom is raised, it will always stop at the set position when it is lowered during operations.

[Cancel method] • Turn the mode selector switch to [depth].

• Turn the set switch to CLEAR and check that the indicator goes out. ¡ The work equipment is stopped by draining the output pressure from the boom PPC valve to the boom control valve (LOWER) at the EPC valve to the tank.

PC75UU-3

10-143 2

STRUCTURE AND FUNCTION

FOUR SYSTEM

4. OFFSET POSITION SETTING SYSTEM • It is possible to set the left offset position before starting, so it is easy to position the offset when carrying out side ditching.

•

Offset setting function (offset mode) • If the work equipment is offset to the left to the desired position, the offset will always stop at that position during operations.

• By limiting the range for left offset operations, it is possible to fix the left offset position continuously during operations.

[Setting method] • Set the mode selector switch to [offset].

• Offset to the left to the desired position.

• Turn the set switch to SET, and check that the buzzer sounds twice and the indicator lights up.

[Operation] • When the work equipment is offset to the right, it will always stop at the set position when it is offset to the left during operations.

[Cancel method] • Turn the mode selector switch to [offset].

• Turn the set switch to CLEAR and check that the indicator goes out.

10-144 2

PC75UU-3

STRUCTURE AND FUNCTION

FOUR SYSTEM

5. BOOM END CUSHION FUNCTION • When the boom is raised, the boom speed is reduced before it is fully raised to reduce shock at the end of the stroke. This function reduces spillage of soil and reduces the load on the chassis and cylinders.

[Operation] • The cushion range is approx. 35° before the end of the boom RAISE stroke.

• When the boom enters this range, the output pressure from the boom PPC valve to the boom control valve (RAISE) is reduced at the EPC valve to reduce the boom speed.

• This makes it possible to reduce the shock at the end of the stroke.

6. ARM END CUSHION FUNCTION • When the arm is moved in, the arm speed is reduced before it is fully moved in (standard arm, long arm: approx. 35°, slide arm: approx.

25°) to reduce shock at the end of the stroke.

This function reduces spillage of soil and reduces the load on the chassis and cylinders.

[Operation] • There is a cushion range (approx. 35° or 25°) before the end of the arm IN stroke.

• When the arm enters this range, the output pressure from the arm PPC valve to the arm control valve (IN) is reduced at the EPC valve to reduce the arm speed.

• This makes it possible to reduce the shock at the end of the stroke.

PC75UU-3

10-145 2

STRUCTURE AND FUNCTION

FOUR SYSTEM

7. SELF-DIAGNOSTIC FUNCTION โ ข The system consists of electronic components such as the solenoid valves and EPC valves that receive the output signals, the controller itself and the potentiometers that send input signals. The controller always observes that these electronic components are functioning normally.

If any abnormality occurs in any of these components, the controller carries out troubleshooting and displays the result as an error code on the depth display inside the monitor panel. At the same time, it flashes the electric system caution lamp and sounds the alarm buzzer to warn the operator of the abnormality. ยก For details of the display and action to take, see TESTING AND ADJUSTING.

10-146 2

PC75UU-3

STRUCTURE AND FUNCTION

FOUR SYSTEM

8. COMPONENTS OF SYSTEM 1) Controller

Input/output signal CN1

CN3

CN2

No.

Name of signal

Input/ output signal

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21

Serial communications (TXD) Serial lock (SCK) Boom RAISE EPC (+) — Arm IN EPC (+) — — Power source input (24V) GND Left offset solenoid (+) Left offset solenoid (+) — — Boom RAISE EPC (–) Arm IN EPC (–) — Solenoid power source input (+24V) Power source input (+24V) GND PPC lock solenoid (+) PPC lock solenoid (+)

Output Output Output — Output — — — — Output Output — — Output Output — — — — Output Output

PC75UU-3

1. Controller 2. Self-diagnostic display

No. 1 2 3 4 5 6 7 8 9

Name of signal Mode selection Mode selection SET CLEAR — Model selection Model selection Model selection Signal GND

Input/ output signal Input Input Input Input — Input Input Input Input

Potentiometer signal power 10 source (+5V) Output 11 Offset stop position reset

Input

Angle, depth, front, rear stop 12 position Input 13 14 15 16 17 18 19 20

System cancel switch Depth display reset Attachment selection Attachment selection Attachment selection Boom pressure switch Boom pressure switch Swing, arm pressure switch

Input Input Input Input Input Input Input Input

No.

Input/ output signal

Name of signal

1 Arm angle potentiometer signal Input Arm slide amount potentiom2 eter signal 3 4 5 6 7 8 9 10 11 12 13 14 15 16

Input

— — —

— — — Serial strobe Output Boom LOWER solenoid (+) Output Boom LOWER solenoid (+) Output Boom angle potentiometer signal Input Offset angle potentiometer signal Input — — Signal GND Input — — Electrical system caution Output — — Swing holding brake solenoid (+) Output

10-147 2

STRUCTURE AND FUNCTION

FOUR SYSTEM

2) Potentiometer

1.

2.

3.

4.

5.

6.

Body Rotor Bearing Sensor Cover Connector

Function â&#x20AC;˘ Potentiometers are installed to the boom foot, arm foot, and 2nd boom top. They detect the angle of the boom, arm, and offset. â&#x20AC;˘ The angle of these parts of the work equipment are converted by the resistance value of the variable resistance to convert the 5V power source voltage to the signal voltage and sent to the controller.

10-148 2

PC75UU-3

STRUCTURE AND FUNCTION

FOUR SYSTEM

3) Cancel resistance

1. Resistance 2. Connector Specifications Resistance value: 5 Ω

Function • This resistance sends a suitable current to the EPC valve (boom RAISE, arm IN) when the cancel switch is ON.

4) Boom RAISE stop EPC valve Arm IN stop EPC valve Boom LOWER stop solenoid valve Left offset stop solenoid valve PPC lock solenoid valve ¡ For details, see SOLENOID, EPC VALVE. 5) Monitor panel ¡ For details, see MONITOR SYSTEM.

PC75UU-3

10-149 2

STRUCTURE AND FUNCTION

ELECTRICAL CONTROL SYSTEM

ELECTRICAL CONTROL SYSTEM TOTAL SYSTEM DIAGRAM

10-150 2

PC75UU-3

STRUCTURE AND FUNCTION

ELECTRICAL CONTROL SYSTEM

PUMP CONTROL FUNCTION

Function â&#x20AC;¢ To reduce the drop in the engine speed when the engine is running at low speed, this function acts to lower the pump absorption torque automatically when the engine is running at low speed.

PC75UU-3

10-151 2

STRUCTURE AND FUNCTION

ELECTRICAL CONTROL SYSTEM

SWING HOLDING BRAKE FUNCTION

Function â&#x20AC;¢ This provides the swing holding brake function.

10-152 2

PC75UU-3

STRUCTURE AND FUNCTION

Outline • When the swing is stopped, the swing holding brake is automatically applied to prevent the occurrence of hydraulic drift on slopes.

• To reduce the load on the swing system during digging operations, it is interconnected with the arm IN operation and releases the swing holding brake.

• There is a switch provided to release the swing holding brake if any abnormality occurs in the timer.

PC75UU-3

ELECTRICAL CONTROL SYSTEM

•

Relationship between swing holding brake cancel switch and brake

Swing holding brake cancel switch

Operation

AUTO

If swing holding brake is set to HOLD, swing holding brake is applied after approx. 4 seconds. When control lever is operated, swing holding brake is canceled and it is possible to swing freely.

OFF (Cancel)

If it is impossible to swing even when swing control lever is operated, turn switch OFF to cancel swing holding brake and make it possible to swing. If switch is OFF, swing holding brake is not applied even when swing control lever is returned to neutral.

10-153 2

STRUCTURE AND FUNCTION

ELECTRICAL CONTROL SYSTEM

TRAVEL SPEED SELECTOR FUNCTION

Function • This machine is equipped with a travel speed selector function.

• A travel speed boost pedal is also installed: release it to go slower, depress it to go faster.

10-154 2

Operation Travel speed Travel speed solenoid Travel motor Travel speed boost pedal valve swash plate (km/h) Released

OFF

Max.

Road liner low speed (2.6)

Depressed

ON

Min.

Road liner high speed (3.7)

PC75UU-3

STRUCTURE AND FUNCTION

ELECTRICAL CONTROL SYSTEM

PPC LOCK FUNCTION

Function • The PPC lock switch is interconnected with the safety lock lever. When the safety lock lever is set to the LOCK position, the PPC lock switch is turned OFF. • When the PPC lock switch is turned OFF, the current flowing to the PPC lock solenoid valve is shut off and the work equipment does not move even if the work equipment control lever is operated.

PC75UU-3

10-155 2

STRUCTURE AND FUNCTION

ELECTRICAL CONTROL SYSTEM

COMPONENTS OF SYSTEM 1) Swing brake timer Serial No.: 15001 – 19000 (monoboom specification)

1. Timer 2. Connector

Function • The timer receives the signal from the swing and arm IN levers, carries out the timer function, and drives the swing brake solenoid valve.

2) PPC oil pressure switch 1.

2.

3.

4.

5.

6.

Plug Contact ring Contact Diaphragm Spring Terminal

3) Controller ¡ For details, see 4 SYSTEM.

10-156 2

PC75UU-3

STRUCTURE AND FUNCTION

MONITOR SYSTEM

MONITOR SYSTEM

•

•

•

The machine monitor system is a system that uses sensors installed at various parts of the machine to observe the condition of the machine. It then processes this information swiftly and displays it on a panel to inform the operator of the condition of the machine.

The panel display can be broadly divided into the following: 1. The monitor portion, which issues a warning when any abnormality is found in the machine.

2. The pilot portion, which displays the condition of the machine when it is operated.

3. The gauge portion, which always displays the condition of the machine.

The 4 system display and operating switches are also installed inside the monitor panel.

PC75UU-3

10-157 2

STRUCTURE AND FUNCTION

MONITOR SYSTEM

1. MONITOR PANEL

Outline • The monitor panel consists of a monitor display, 4 system display, and operating switches.

• It has a built-in CPU (Central Processing Unit) which processes the data and outputs the display.

• A liquid crystal display is used for the gauge display.

• Lamps are used for the monitor display.

• A liquid crystal display is used for the 4 system display and indicators.

Input/output signals CN-P1 No.

Name of signal

1 Power source (+24V) 2 LOAD

Input/ output No. signal

–

Name of signal

9 Engine oil pressure Input

Input 10 Charge level

3 GND 4 GND (CNT.) 5 Starting signal

Input/ output signal

Input

–

11 Electrical system

Input

–

12 CLOCK

Input

Input 13 Preheating

Input

6 Coolant temperature Input 14 Battery electrolyte level Input 7 Fuel level

Input 15 Buzzer output

Output

8 DATA

Input 16 Night lighting input Input

CN-K30 No.

Name of signal

1

–

2 Selection 1

Input/ output No. signal

–

Name of signal

3 GND

Input/ output signal

–

Output 4 Selection 2

Output

CN-K31 No.

Name of signal

1 GND 2 CLEAR

10-158 2

Input/ output No. signal

–

Name of signal

3 SET

Input/ output signal

Output

Output

PC75UU-3

STRUCTURE AND FUNCTION

1.

2.

3.

4.

5.

6.

7.

Service meter Preheating pilot lamp Coolant temperature gauge Fuel gauge Setting switch Mode selection switch Depth display (error code display)

PC75UU-3

MONITOR SYSTEM

8.

9.

10.

11.

12.

13.

14.

Offset mode indicator Height mode indicator Depth mode indicator Electrical system caution lamp Battery electrolyte level caution lamp Battery charge caution lamp Engine oil pressure caution lamp

10-159 2

STRUCTURE AND FUNCTION

MONITOR SYSTEM

PANEL DISPLAY Display category Symbol Checks before starting

SVP04532

Display item

Display range

Display method When starting switch is ON, engine stopped, display is as follows: Normal : OFF Abnormal: ON, buzzer sounds

Battery electrolyte level

Below low level

Engine oil pressure

Below 49 kPa {0.5 kg/cm2}

Charge amount

When there is defective charging

SAP00520

CAUTION

SAP00522

Electrical Electrical system system

Gauge

When there is abnormality in 4 system

Display is as follows: Normal : OFF Abnormal: ON (buzzer sounds if abnormality occurs when engine is running) Display is as follows: Normal : OFF Abnormal: Flashes (buzzer sounds at same time) One lamp lights up to show the temperature

Coolant temperature

 When it enters the highest level, the seg-  ment flashes and the buzzer sounds 

Fuel level

 When it enters the lowest level, the seg-    ment flashes and the buzzer sounds

SAD01482

One lamp lights up to show the level

SAD01486

Pilot lamp

Preheating

When the starting switch is at HEAT, lamp is ON (18 sec); and after this it goes OFF to indicate completion of preheating

When preheating

SAD00708

¡ For details of the display and operation of the following items, see 4 System.

5. Setting switch 6. Mode selection switch 7. Depth display portion (error code display portion)

8.

9.

10.

11.

Offset mode indicator Height mode indicator Depth mode indicator Electric system caution lamp

¡ The battery electrolyte level caution lamp was used for Serial No.: 15001 – 19000.

10-160 2

PC75UU-3

STRUCTURE AND FUNCTION

MONITOR SYSTEM

2. SENSOR • •

The signals from the sensors are input directly to the monitor panel.

The contact type sensors are always connected at one end to the chassis ground.

Category of display

Type of sensor

Sensor method

When normal

When abnormal

Min. 3V

0 V (not tired)

OFF (open)

ON (closed)

Checks before starting

Battery electrolyte level

Pole

Caution

Engine oil pressure

Contact

Coolant temperature

Resistance

—

—

Fuel level

Resistance

—

—

Gauges

1) Battery electrolyte level sensor Serial No.: 15001 – 19000 1. Pole 2. Connector

2) Engine oil pressure sensor 1.

2.

3.

4.

5.

6.

PC75UU-3

Plug Contact ring Contact Diaphragm Spring Terminal

10-161 2

STRUCTURE AND FUNCTION

MONITOR SYSTEM

3) Coolant temperature sensor

1. Connector 2. Plug 3. Thermistor

4) Fuel level sensor

1.

2.

3.

4.

Float Connector Cover Variable resistance

10-162 2

PC75UU-3

TESTING AND ADJUSTING

E-4

E-4 Error code [31] (Abnormality in boom potentiometer system) ¡ Before carrying out troubleshooting, check that all the related connectors are properly inserted. ¡ Always connect any disconnected connectors before going on the next step.

Cause 2

YES

Is [31] displayed YES under same conditions as when measuring Item 1?

• Turn starting switch ON.

NO

Defective controller

Returns to normal

Remedy

Replace

—

Defective contact, or disconnection in wiring Repair wiring 4 YES harness between K2 (female) harness, or (9), (10) – K12 (7), (9) – M11 Is voltage Is resistance in (male) (1), (3) or wiring replace between K3 (9) wiring harness harness short circuiting with and (12) normal? between K3 (female) ground YES (9) and M11 (male) • 0.3 – 4.7 V (2) normal, and is Defective contact, or discircuit insulated from • Turn starting connection in wiring harchassis? switch ON. Repair wiring ness between K3 (female) (9) 3 harness, or • Disconnect K3 – K12 (8) – M11 (male) (2) or NO Is resistance betand M11. replace wiring harness short ween M11 • Turn starting circuiting with ground (female) (3) – (1), switch OFF. NO and (2) – (1) as • Resistance value shown in Table 1? of wiring harness: Max 10 Ω • Turn starting • Between wiring switch OFF. harness and chassis: • Disconnect M11.

Max 10 Ω Defective boom potenti-

1

NO

ometer

Replace

Table 1 M11 (male) Between (3) — (1) Between (2) — (1)

Resistance 4—6kΩ 0.2 — 7 k Ω

E-4 Related electrical circuit diagram

PC75UU-3

20-427

TESTING AND ADJUSTING

E-5

E-5 Error code [32] (Abnormality in arm potentiometer system) ¡ Before carrying out troubleshooting, check that all the related connectors are properly inserted. ¡ Always connect any disconnected connectors before going on the next step.

Cause 2

YES

Defective controller

Is [32] displayed YES under same conditions as when measuring Item 1?

• Turn starting switch ON.

1 Is voltage between K3 (1) and (12) normal?

Returns to normal

NO

Remedy

Replace

—

Defective contact, or disconnection in wiring harness between K2 Repair wiring 4 YES (female) (9), (10) – K12 (12), harness, or (10) – K13 (6), (4) – M12 Is resistance in replace (female) (3), (1) or wiring wiring harness harness short circuiting with between K3 ground YES (female) (1) and

• Turn starting switch ON. • 0.3 – 4.7 V

3 Is resistance between M12 (male) (1) – (3), and NO (2) – (1) as shown in Table 1?

• Turn starting switch OFF. • Disconnect M12.

M12 (female) (2) normal, and is circuit insulated from chassis?

Defective contact, or disconnection in wiring harRepair wiring ness between K3 (female) (1) – K12 (11) – K13 (5) – M12 harness, or NO (female) (2), or wiring harreplace ness short circuiting with ground

• Disconnect K3 and M12.

• Turn starting switch OFF. • Resistance value of wiring harness: Max 10 Ω • Between wiring harness and chassis: Max 1M Ω

NO

Defective boom arm potentiometer

Replace

Table 1 M12 (male) Between (1) – (3) Between (2) – (3)

Resistance 4–6kΩ 0.2 – 7 k Ω

E-5 Related electrical circuit diagram

20-428 2

PC75UU-3

E-8

TESTING AND ADJUSTING

E-8 Error code [38] (Abnormality in slide arm length sensor system) is displayed Slide arm (telescopic arm) specification machine ¡ Before carrying out troubleshooting, check that all the related connectors are properly inserted. ¡ Always connect any disconnected connectors before going on the next step.

Cause 2

YES

[38]] displayed Is [34 displayed YES under under same sameconconditions as as when when ditions measuring Item Item1?

1? measuring

• Turn starting switch ON.

1 Is voltage between K3 (2) and (12) normal?

• Turn starting switch ON. • 0.3 – 4.7 V

NO

System has been reset

Replace

—

Defective contact, or disconnection in wiring harness between K2 4 YES (female) (9), (10) – K12 (13), Repair or (15) – K13 (7), (9) – M12 (6), replace Is resistance in (8) – M61 (female) (1), (3), or wiring harness wiring harness short between K3 circuiting with ground YES (female) (2) and M61 (female) (2) Defective contact or normal, and is disconnection in wiring circuit insulated harness between K3 from chassis?

Repair or (female) (2) – M6 (7) – K13

3 Is resistance between M61 (male) (3) – (1), and (2) – NO (1) as shown in Table1?

• Turn starting switch OFF. • Disconnect M61.

• Turn starting switch OFF. • Disconnect K3 and M61.

• Resistance value of wiring harness: Max. 10 Ω • Between wiring harness and chassis: Min. 1 M Ω

NO Table 1 M61(male) Between (3) – (1) Between (2) – (1)

Defective controller

Remedy

NO (10) – M12 (7) – M61

replace

(female) (2), or wiring harness short circuiting with ground

Defective slide arm length sensor

Replace

Resistance 4–6kΩ 0.2 – 7 k Ω

E-8 Related electrical circuit diagram

PC75UU-3

20-431

TESTING AND ADJUSTING

E-9

E-9 Error code [41] (Abnormality in PPC lock solenoid system) ¡ Before carrying out troubleshooting, check that all the related connectors are properly inserted. ¡ Always connect any disconnected connectors before going on the next step. ¡ This detects only short circuits between wires or the wiring harness between the controller and the solenoid circuiting with the ground. ¡ If movement stops but no abnormality display is given, go to E-OO.

Cause

2 YES Is there continuity in wiring harness betYES ween K1 (female) (20), (21) and V1, and is circuit 1 insulated from Is resistance between V1 (male) (1) and (2) normal, and is circuit insulated from chassis?

• Turn starting switch OFF.

• 35 – 80 Ω • Between V1 – chassis: Min. 1 M Ω • Disconnect V1

• Turn starting NO switch OFF. • Disconnect K1 and V1.

• Measure fromK1 (female) end with diode range. (Note)

NO

Defective controller

Remedy

Replace

Wiring harness between Repair wiring K1 (female) (20) , (21) – DA2 – K12 (3) – V1 (female) harness, or replace (1) short circuiting with ground

Defective PPC lock solenoid

Replace

Note: If a normal tester is switched to the diode range, the voltage of the internal battery is displayed.

When checking a wiring harness containing a diode, the change in this voltage is judged as follows: Change = Continuity No change = No continuity

E-9 Related electrical circuit diagram

20-432 2

PC75UU-3

TESTING AND ADJUSTING

E-10

E-10 Error code [42] (Abnormality in left offset stop solenoid system) ¡ Before carrying out troubleshooting, check that all the related connectors are properly inserted. ¡ Always connect any disconnected connectors before going on the next step. ¡ If the wiring harness between the controller and the solenoid is short circuiting with the ground, a display is given during operations. In the case of a disconnection, no display is given, but the work equipment stops.

If this happens, turn the starting switch OFF, then ON again, and the display is given.

Cause

3 YES Is resistance betYES ween K50 (1) and chassis ground 2 normal?

Is there continuity in wiring harness YES between K1 (female) (10), (11) and K50 (2) and is circuit insu1 lated from chassis?

Is resistance between K50 (male) (2), (1) normal, and is circuit insulated from

• Turn starting switch OFF. • Max.10 Ω • Disconnect K52

• Turn starting switch OFF. NO • Disconnect K1 and K50.

• Measure from K1 (female) end with diode range. (Note)

• Turn starting switch OFF. • 35 – 80 Ω NO • Between K50 (male) (1) and chassis: Min. 1 M Ω • Disconnect K50

Defective controller

Defective contact, or disconnection in wiring harness between K50 NO (male) (1) and chassis ground

Remedy

Replace

Repair wiring harness, or replace

Defective contact, or disconnection in wiring harness between K1 (female) (10), (11) DA4 – M6 (9) – K50 (female) (2) or wiring harness short circuiting with ground

Repair wiring harness, or replace

Defective left offset stop solenoid

Replace

Note: If a normal tester is switched to the diode range, the voltage of the internal battery is displayed.

When checking a wiring harness containing a diode, the change in this voltage is judged as follows: Change = Continuity No change = No continuity

E-10 Related electrical circuit diagram

PC75UU-3

20-433 2

TESTING AND ADJUSTING

E-11

E-11 Error code [44] (Abnormality in boom LOWER stop solenoid system) ¡ Before carrying out troubleshooting, check that all the related connectors are properly inserted. ¡ Always connect any disconnected connectors before going on the next step. ¡ If the wiring harness between the controller and the solenoid is short circuiting with the ground, a display is given during operations. In the case of a disconnection, no display is given, but the work equipment stops.

If this happens, turn the starting switch OFF, then ON again, and the display is given.

Cause

3 YES Is resistance betYES ween K51 (female) (2) and chassis 2 ground normal?

Is there continuity in wiring harness • Max.10 Ω YES between K3 (female) • Disconnect K51 (7), (8) and K51, and • Turn starting is circuit insulated switch OFF. 1 from chassis?

Is resistance between K51 (male) (2) – (1) normal, and is circuit insulated from chassis?

• Turn starting switch OFF. NO • Disconnect K3 and K51.

• Measure from K3 (female) end with diode range. (Note)

• Turn starting switch OFF. • 35 – 80 Ω NO • Between K51 (male) (1) and chassis: Min. 1 M Ω • Disconnect K51

Defective controller

Defective contact, or disconnection in wiring harness between K51 NO (female) (1) and chassis ground

Remedy

Replace

Repair wiring harness, or replace

Defective contact, or disconnection in wiring harness between K3 (female) (7), (8) – DA3 – M6 (8) – K51 (female) (2), or wiring harness short circuiting with ground

Repair wiring harness, or replace

Defective boom LOWER stop solenoid

Replace

Note: If a normal tester is switched to the diode range, the voltage of the internal battery is displayed.

When checking a wiring harness containing a diode, the change in this voltage is judged as follows: Change = Continuity No change = No continuity

E-11 Related electrical circuit diagram

20-434 2

PC75UU-3

TESTING AND ADJUSTING

E-12

E-12 Error code [51] (Abnormality in boom RAISE stop solenoid system) ¡ Before carrying out troubleshooting, check that all the related connectors are properly inserted. ¡ Always connect any disconnected connectors before going on the next step.

Cause

3 YES

YES

Is resistance in wiring harness between K1 (female) (14) and K52 (female) (1) normal, and is circuit insulated from chassis?

Defective controller

Defective contact, or disconnection in wiring 2 harness between K1 Is there continuity in (female) (14) – K52 (male) • Turn starting switch NO (1), or wiring harness wiring harness betYES ween K1 (female) (3) OFF short circuiting with • Between wiring and K52 (female) (2), ground harnesses: Max. 10 Ω and is circuit insu1 • Between wiring lated from chassis? harnesses and chasses: Defective contact, or Is resistance bet• Turn starting Min. 1 M Ω disconnection in wiring ween K52 (male) switch OFF. • Disconnect K1 and K52 harness between K1 (2) and (1) normal, (female) (3) – K52 (female) • Disconnect K1 and and is circuit insu(2), or wiring harness K52.

NO lated from chassis? short circuiting with • Measure from K1 • Turn starting ground (female) end with diode range. (Note) switch OFF. Defective boom LOWER • 5 – 25 Ω stop solenoid NO • Between K52 (male) (1) and chassis: Min. 1 M Ω • Disconnect K52

Remedy

Replace

Repair wiring harness, or replace

Repair wiring harness, or replace

Replace

Note: If a normal tester is switched to the diode range, the voltage of the internal battery is displayed.

When checking a wiring harness containing a diode, the change in this voltage is judged as follows: Change = Continuity No change = No continuity

E-12 Related electrical circuit diagram

PC75UU-3

20-435 2

E-13, E-14

TESTING AND ADJUSTING

E-13 Error code [52] (Abnormality in arm IN stop EPC solenoid system) is displayed ¡ Before carrying out troubleshooting, check that all the related connectors are properly inserted. ¡ Always connect any disconnected connectors before going on the next step.

3 YES 2 Is there continuity in wiring harness betYES ween K1 (female) (5) and K53 (female) (2), and is circuit insu1 lated from chassis?

Is resistance between K53 (male) (1) and (2) normal, and is circuit insulated

Is resistance in wiring harness between K1(female) (15) and K53 (female) (1) normal, and is cir cuit insulated from chassis?

Cause

YES

Defective contact or disconnection in wiring harness between K1 NO (female) (15) - K53 (female) (1), or wiring harness short circuiting

• Turn starting switch OFF. • Between wiring harnesses: Max. 10 Ω • Between wiring harness and chassis: Min. 1 M Ω • Disconnect K1 and K53.

• Turn starting switch OFF. • Disconnect K1 and NO K53.

• Measure from K1 (female) end with diode range. (Note)

• Turn starting switch OFF. • Between K53 NO (male) (1) – (2): 3 – 15 Ω • Between K53 (male) (1) – chassis: Min. 1 M Ω • Disconnect K53.

Defective controller

Remedy

Replace

Repair wiring harness, or replace e

Defective contact or disconnection in wiring harness between K1 Repair wiring (female) (5) - K53 (female) harness, or (2), or wiring harness replace short circuiting with ground Defective arm IN stop solenoid

Replace

Note: If a normal tester is switched to the diode range, the voltage of the internal battery is displayed.

When checking a wiring harness containing a diode, the change in this voltage is judged as follows: Change = Continuity No change = No continuity

E-13 Related electrical circuit diagram

E-14 Error code [61] (valve open) is displayed ¡ Impossible to measure electrical system.

1. There is dirt clogging the valve of the EPC solenoid for boom RAISE stop, arm IN stop, or offset stop, and the valve remains open (the bucket is inside the interference range).

2. Water has got into the connectors (K18, K50, K52) of the potentiometers for the boom, arm, and offset.

20-436 2

PC75UU-3

TESTING AND ADJUSTING

E-16

E-16 Impossible to select and set depth display 0 set mode, depth mode, height mode, offset mode ¡ Before carrying out troubleshooting, check that all the related connectors are properly inserted. ¡ Always connect any disconnected connectors before going on the next step. ¡ Check that the selection and setting is being carried out outside the interference area.

Remedy

Cause

YES

Defective controller

2 Is voltage bet-

Defective contact, or disconnection in wiring harness between K31 (female) Repair wiring (2), (3) and K2 (female) (4), harness, or replace (3)

YES ween K2 (3), (4), and (9) as shown in Table 2?

1

• Turn starting switch ON.

Is voltage between K2 (1), (2), and (9) as shown in Table 1?

• Turn starting switch ON.

4 YES Is continuity between setting NO switch terminals as shown in table 2?

• Turn starting switch OFF.

Defective setting switch

Defective contact, or disconnection in wiring har- Repair wiring ness between K30 (female) harness, or (1), (2) and K2 (female) (2), replace (1)

Is continuity between selection NO switch terminals as shown in table 1?

Defective selection switch Replace

NO

Table 2

Table 1 Terminal No. of controller K2

Position

Depth display 0 set Depth Height Offset

Terminal No. of controller K2 1

2

(Min. 8 V) (Min. 8 V) (Max. 1 V) (Min. 8 V) (Min. 8 V) (Max. 1 V)

3 (GND)

4 Setting switch Position

Switch terminal No. Setting switch

Replace

NO

3 YES

• Turn starting switch OFF.

Replace

Switch terminal No. SET Neutral CLEAR

1 (GND)

2

3 (GND)

(Min. 8 V) (Max. 1 V) (Min. 8 V) (Min. 8 V) (Max. 1 V) (Min. 8 V)

(Max. 1 V) (Max. 1 V)

Nos. 1 and 4 are connected externally.

E-16 Related electrical circuit diagram

PC75UU-3

20-439

TESTING AND ADJUSTING

E-17

E-17 Cancel switch is not turned ON, but alarm buzzer sounds for 7 seconds and electric system caution lamp flashes ¡ Before carrying out troubleshooting, check that all the related connectors are properly inserted. ¡ Always connect any disconnected connectors before going on the next step.

Cause

2 YES

Remedy

Defective monitor panel

Replace

Defective controller

Replace

Wiring harness between K2 (female) (13) and cancel switch terminal (1) in contact with power source wiring harness

Repair wiring harness, or replace

Defective cancel switch

Replace

YES Is voltage

between K3 (14) and (12) normal?

1

• Turn starting switch ON. • When normal: 20 – 30 V • When abnormal: Max. 1 V

Is voltage between K2 (13) and (9) normal?

• Turn starting switch ON. • Cancel switch When OFF: Max. 1 V When ON: 20 – 30 V

NO

3 YES

Is continuity between cancel switch terminals (1) and NO (2) as shown in Table 1?

• Turn starting switch OFF.

NO

Table 1 Switch ON (Up)

1

2

3

OFF (Down)

E-17 Related electrical circuit diagram

20-440 2

PC75UU-3

TESTING AND ADJUSTING

E-18

E-18 Automatic stop is not carried out for boom RAISE, arm IN, left offset (when error code [61] is not displayed) ยก Before carrying out troubleshooting, check that all the related connectors are properly inserted. ยก Always connect any disconnected connectors before going on the next step. ยก Check that error code [61] is not being displayed. a) All operations stop immediately before interference

Cause

Internal resistance of diode DA2 is 0

Remedy

Replace

ยก For details of the method of checking the diode, see TESTING AND ADJUSTING.

E-18 a) Related electrical circuit diagram

b) There is interference

ยก For details of the method of checking the diode, see TESTING AND ADJUSTING.

Cause

Internal resistance of diode DA4 is 0

Remedy

Replace

E-18 b) Related electrical circuit diagram

PC75UU-3

20-441

TESTING AND ADJUSTING

E-19

E-19 When telescopic arm is extended (more than 200 mm) automatic stop distance is near Telescopic arm (slide arm) specification machine ¡ Before carrying out troubleshooting, check that all the related connectors are properly inserted. ¡ Always connect any disconnected connectors before going on the next step. ¡ Check that the telescope limit switch has come back fully (is not still pushed in).

Cause

1 YES Is resistance between M63 (male) (1) and (2) normal?

• When arm is extended: Min. 1 M Ω • When arm is retracted: Max. 1 Ω • Turn starting switch OFF. • Disconnect M63.

NO

Remedy

Defective controller

Replace

Defective telescope limit switch (slide arm fully retracted is detected)

Replace

E-19 Related electrical circuit diagram

20-442 2

PC75UU-3

TESTING AND ADJUSTING

E-20

E-20 When slide arm is retracted (less than 200 mm) automatic stop distance is far Slide arm (telescopic arm) specification machine ¡ Before carrying out troubleshooting, check that all the related connectors are properly inserted. ¡ Always connect any disconnected connectors before going on the next step. ¡ Check that the telescope limit switch is being pressed properly.

Cause

3 YES Is resistance beYES tween M63 2 (male) (2) and Is resistance bechassis normal?

YES tween M63 (fe• Max. 1 Ω male) (3) and K2 • Disconnect M63.

1 (female) (18) normal?

Is resistance between M63 (male) (1) and (3) normal?

• When arm is extended: Min. 1 M Ω • When arm is retracted: Max. 1 Ω.

• Turn starting switch OFF. • Disconnect K63.

• Max. 1 Ω NO • Turn starting switch OFF. • Disconnect M63 and K2.

NO

NO

Remedy

Defective controller

Replace

Defective contact or disconnection in wiring harness between M63 (female) (1) and chassis with ground

Repair wiring harness, or replace

Defective contact or disconnection in wiring har ness between M63 (female) (2) and K2 (female) (18)

Repair wiring harness, or replace

Defective telescope limit switch (slide arm fully retracted is detected)

Rreplace

E-20 Related electrical circuit diagram

PC75UU-3

20-443 2

TESTING AND ADJUSTING

E-21

E-21 Work equipment does move when work equipment lock lever is set to FREE position ¡ Before carrying out troubleshooting, check that all the related connectors are properly inserted. ¡ Always connect any disconnected connectors before going on the next step. ¡ For this system only, no self-diagnosis display is given for disconnections. ¡ When error code [61] (valve open) is not displayed.

Cause

YES

Go to H-3.

Remedy

Replace

• Defective diode DA2

4 YES • Defective contact or

1 Is voltage between S7 (2) and chassis normal?

Is resistance

YES between S7 (female) (1) and 3 Is resistance bet-

YES ween S7 (female)

• Turn starting (2) and V1 switch ON. 2 (female) (2) • When lever is normal?

Is resistance of locked: 20 – 30 V • Max. 10 Ω lock switch • When lever is • Turn starting released: NO normal? switch OFF. Max. 1 V • Disconnect S7.

• Turn starting switch OFF. NO • When lever is locked: Min. 1 M Ω • When lever is released: Max. 1 Ω

chassis ground • Max. 10Ω • Turn starting switch OFF. • Disconnect S7.

NO

disconnection in wiring harness between K(20), (21) and V1 (female) (1)

Repair wiring harness , or replace

Defective contact or disconnection in wiring NO harness between S7 (1) and chassis ground

Repair wiring harness , or replace

Defective contact or disconnection in wiring harness between S7 (2) and V1 (female) (2)

Repair wiring harness , or replace

Defective PPC lock switch

Replace

E-21 Related electrical circuit diagram

20-444 2

PC75UU-3

TESTING AND ADJUSTING

E-23

Cause

7 YES Does condition become normal when D14 is replaced?

NO

Remedy

Defective diode (D14)

Replaces

Defective controller

Replaces

Short circuit, defective contact or disconnection in wiring harness between DA4 (female) (1) and V2 (female) (1), or contact with ground wiring harness

Repair or replace

Short circuit, defective contact or disconnection in wiring harness between K3 (female) (16) and DA4 (female) (2), or contact with ground wiring harness

Repair or replace

Defective contact or Repair or disconnection in wiring harness between K2 (female) (20) replace â&#x20AC;&#x201C; S12, S13, S14 (female) (2)

PC75UU-3

Defective contact or disconnection in wiring harness between S12, S13, S14 (female) (1) â&#x20AC;&#x201C; chassis

Repair or replace

Short circuit with ground wiring harness between K2 (female) (10) - M11 (female) (3), M12 (female) (1), M13 (female) (3), or short circuit with ground

Repair or replace

Defective swing holding brake solenoid

Replaces

20-447 2

TESTING AND ADJUSTING

E-23

E-23 Related electrical circuit diagram

20-448

PC75UU-3

TESTING AND ADJUSTING

E-25

E-25 Even when travel boost pedal is operated (depressed), speed does not increase ¡ Before carrying out troubleshooting, check that all the related connectors are properly inserted. ¡ Always connect any disconnected connectors before going on the next step. ¡ When fuse 5 is normal. (If fuse 5 is blown, check for a short circuit with the ground between fuse box and V3 (female) (1).

Cause

3YES

Is continuity bet-

Is resistance betYES ween S5 (female) (1) and chassis 2 ground normal?

YES ween travel boost 1 When travel boost pedal switch is OFF (not depressed), is voltage between switch (S5 (2) side) and chassis normal?

pedal switch terminals normal?

• Turn starting switch OFF. • Max. 1 Ω • Disconnect S5.

NO

• When pedal switch is OFF (depressed): NO Max. 1 Ω • When pedal switch is OFF (not depressed): Min. 1 M Ω • Turn starting switch OFF. • Disconnect travel boost pedal switch terminal.

Is resistance of • Turn starting travel boost switch ON. solenoid {between • Approx. 24 V NO V3 (male) (1) and • Place travel (2)} normal? boost pedal • 35 – 80 switch at OFF • Turn starting (not depressed) switch OFF. position.

• Disconnect V3.

4 YES

NO

Go to H-20

Remedy

—

Defective contact or disconnection in wiring Ripare or harness between S5 (female) (1) (travel boost replace pedal switch) and chassis ground Defective travel boost pedal switch

Replace

Disconnection in fuse 5, or defective contact or disconnection in wiring harness between fuse box and V3 (female) (1) ground

Ripare or replace

Defective travel boost solenoid

Replace

E-25 Related electrical circuit diagram

PC75UU-3

20-453 2

E-26

TESTING AND ADJUSTING

E-26 Travel boost pedal is not being operated (not depressed) but speed remains boosted ¡ Before carrying out troubleshooting, check that all the related connectors are properly inserted. ¡ Always connect any disconnected connectors before going on the next step.

Cause

YES

Go to H-20

1 Is voltage between V3 (1) and chassis normal?

Remedy

2 YES Is continuity between travel boost pedal switch terminals {S5 (male) (1) and (2)} normal?

• When travel boost pedal NO switch is ON (depressed): • When pedal NO Approx. 24 V switch is ON • Place travel (depressed): Max. 1 Ω boost pedal • When pedal switch is OFF switch at OFF (not depressed): Min. 1 M Ω (not depressed) • Turn starting switch OFF. position: • Disconnect travel boost pedal terminal.

Approx. 0 V

Short circuit with ground in wiring harness between V3 (female) (2) Ripair or (travel boost solenoid) and S5 (female) (2) (travel replace boost pedal switch) Defective travel boost pedal switch

Replace

E-26 Related electrical circuit diagram

20-454 2

PC75UU-3

TESTING AND ADJUSTING

E-27

E-27 Power mode does not switch ¡ Before carrying out troubleshooting, check that all the related connectors are properly inserted. ¡ Always connect any disconnected connectors before going on the next step. ¡ When fuse 2 is normal. a) When engine speed is at mid-range speed or above (limit switch ON) but work equipment speed is slow Cause

4 YES YES Is resistance between V4 (female) 3 (2) – S15 normal?

YES 2

Is resistance between V4 (male) (1) – (2), and between V4 (male) (2) – chassis normal?

• 35 – 80 Ω • Between V4 (male) (2) – chassis: Min. 1 M Ω • Turn starting switch OFF. • Disconnect V4.

Is voltage YES between V4 (1) and chassis 1 normal?

• Turn starting switch ON. • 20 – 30 V

Is resistance between fuel lever limit switch terminals normal?

• Max. 1 Ω • Turn starting switch OFF. • Disconnect V4.

Defective contact or disconnection in wiring NO harness between V4 (female) (2) and S15

• Check switch as individual part.

NO • ON : Max. 1 Ω • OFF : Min. 1 M Ω • Turn starting switch OFF. • Disconnect fuel lever limit switch terminal.

NO

NO 5 YES Is resistance betFrom A ween limit switch terminal S18 and chassis normal?

• Max. 1 Ω • Turn starting switch OFF. • Disconnect S18

Go to A

Remedy

—

Repair or replace

Defective fuel lever limit switch

Replace

Defective contact or disconnection in wiring harness between fuse 5 and V4 (female) (1)

Repair or replace

Defective mode selector solenoid

Replace

Go to H-1 c)

efective contact or disconnection in wiring harness between limit NO switch terminal S18 and chassis ground

Repair or replace

E-27 a) Related electrical circuit diagram

PC75UU-3

20-455 2

TESTING AND ADJUSTING

E-27

b) Excessive drop in engine speed when engine speed is below mid-range speed (limit switch ON)

Cause

2 YES Is resistance betYES ween V4 (female) 1 (2), S15 – chassis normal?

Is resistance bettween fuel lever NO • Min. 1 M Ω limit switch termi• Turn starting nals normal? switch OFF. • Disconnect V4 and S15.

• Check switch as individual part.

• ON : Min. 1 M Ω • OFF : Max. 1 Ω • Turn starting switch OFF. • Disconnect fuel lever limit switch terminal.

NO

Go to H-1 c)

Remedy

—

Short circuit with chassis ground in wiring harness between V4 (female) (2) and S15

Repair or replace

Defective fuel lever limit switch

Replace

E-27 b) Related electrical circuit diagram

20-456 2

PC75UU-3

E-28

TESTING AND ADJUSTING

E-28 Wiper does not work ¡ Before carrying out troubleshooting, check that all the related connectors are properly inserted. ¡ Always connect any disconnected connectors before going on the next step.

Cause

3 YES Is resistance betYES ween M18 (female) (4) and 2 M25 (female) (1)normal?

YES

1 Is voltage between M25 (3) and (2) normal?

• Turn starting switch ON. • 20 – 30 V

Is resistance between wiper switch terminals B and L normal?

• Between B and L Switch ON.: Max. 1 Ω Switch OFF.: Min. 1 M Ω

NO • Max. 1 Ω • Turn starting switch OFF. • Disconnect M18 and M25.

NO

4 YES

Does room lamp

Remedy

Defective wiper motor

Replace

Defective contact or disconnection in wiring harness between M25 (female) (4) (wiper switch terminal L) and M25 (female) (1)

Repate or replace

Defective wiper switch

Replace

Defective contact or disconnection in wiring harness between fuse 4 M1 (2) - M18 (female) (3)

Repate or replace

Blown fuse 4

Replace

NO light up?

• When room lamp NO as individual part is normal (room lamp and wiper motor circuit are the same).

E-28 Related electrical circuit diagram

PC75UU-3

20-457 2

TESTING AND ADJUSTING

E-29

E-29 Engine does not start ¡ Before carrying out troubleshooting, check that all the related connectors are properly inserted. ¡ Always connect any disconnected connectors before going on the next step. a) Starting motor does not turn

5 YES 4 Is voltage between YES starting motor terminal B and chassis normal?

• Turn starting switch ON. • Approx. 24 V

YES

Is voltage between alternator terminal R (starting safety relay terminal R) and chassis normal?

• Max. 13 V • Turn starting switch ON.

NO

NO

3 8 YES

YES Is there sound of

starting motor pinion engaging?

YES 7

• Turn starting switch ON. • Approx. 24 V

Is voltage between

YES starting safety 6

2 When starting

• Turn starting switch to START. • 20 – 29 V

YES switch is turned OFF, is sound heard from battery relay?

• Turn starting switch to START. • 20 – 29 V

NO

NO

NO

• urn starting switch ON → OFF.

11 YES

YES 10

1

Is there YES continuity between starting switch terminals 9 B and BR?

Are voltage and specific gravity of battery normal?

Is voltage of starting switch NO terminal B normal?

• Voltage: Min. 24 V • Specific gravity: Min. 1.26

• Turn starting switch to START. • 20 – 29 V

relay terminal S and chassis normal?

Is voltage between starting switch NO terminal C and chassis normal?

Is voltage between starting safety relay terminal C and chassis normal?

Is resistance of wiring harness between starting switch BR and battery relay BR and resistance between wiring harness and chassis normal?

• Measure from BR end NO of starting switch with diode range. (*1) • Between wiring harness - chassis: Min. 1 M Ω • Disconnect at both starting switch and battery relay ends.

• Turn starting switch ON. NO • Remove terminal B.

• Connect (–) pole of tester to (–) termiNO nal of battery.

• 20 – 29 V

NO

Note:

If a normal tester is switched to the diode range, the voltage of the internal battery is displayed.

When checking a wiring harness containing a diode, the change in this voltage is judged as follows: Change = Continuity No change = No continuity

20-458

PC75UU-3

TESTING AND ADJUSTING

E-31

E-31 Defective engine control ¡ Before carrying out troubleshooting, check that all the related connectors are properly inserted. ¡ Always connect any disconnected connectors before going on to the next step. ¡ Check that there is no damage or extreme bending of the fuel control cable. ¡ Check that the decelerator indicator lamp is OFF. (If it is lighted up, the engine speed will be maintained at low idling.) a) Does not work, or works and then stops working

YES

Defective contact or

4YES disconnection in wiring

Is operation normal if cableis disconnec tedat accelerator motor end?

YES 3 Is voltage bet-

YES ween each termi2 Is voltage between K5 (1) and GND normal?

• Turn starting switch ON. • 20 – 30 V

Remedy

Defective operation of fuel Adjust control linkage

1

NO

Cause

nal of K6 (female) as shown in Table 1?

Is continuity between each terminal of accelerator motor as shown in Table 2?

• Turn starting switch OFF. • Disconnect K7.

• Turn starting switch ON. NO • Disconnect K6 and connect T-adapter to (female) end.

NO

harness between K6 (male) and K7 (female) Defective accelerator

NO motor

Repair wiring harness, or replace

Replace

Defective motor relay box

Replace

• Blown fuse 1, or • Defective contact or disconnection in wiring harness between fuse 1 and K5 (female) (1)

Repair wiring harness, or replace

E-31 a) Related electrical circuit diagram

PC75UU-3

20-463 2

TESTING AND ADJUSTING

E-31

Table 1 Motor relay box (controller) actuation check Connector pin No. and operation at control end Connector and pin No. CN-K6 (female) 1 2 3

Between (2) – (5)

Type of signal

Details of operation

Connector pin No. and operation inspection end Connector and pin No. Voltage (V)

CN-K6 (female) Accelerator signal

Short (acceleration) Open (neutral)

Between (1) – (4)

20 – 30 0 (Both terminals +24V) 1

Short (deceleration) Between (2) – (6) Between (2) – (3) Press knob switch at same time

Decelerator signal Swift slow-down signal

Open (neutral) Short (swift slow-down) Open (neutral)

Between (4) – (1) 2 Between (4) – (1)

0 (Both terminals +24V) 1 0 (Both terminals +24V) 1

k 1. Both terminals are + 24V, so 24V is measured between (1) – GND and between (4) and GND. k 2. The motor drive terminal voltage is reversed for acceleration and deceleration.

•

Procedure for checking actuation (1) Disconnect CN-K6 and connect T-adapter to female side only.

(2) Do not disconnect CN-K5.

(3) Turn the starting switch ON, carry out the operation in Table 1, and measure the motor drive voltage.

20-464

PC75UU-3

DISASSEMBLY AND ASSEMBLY

FUEL INJECTION PUMP

89 •

Install the fuel injection pump assembly in the following procedure.

(1) Using the tool A1, gradually turn the engine in normal direction until the No. 1 cylinder compression top dead center positioning pin (24) is driven into the gear. ¡ Refer to the following information in order to ensure positive insertion of the pin into the gear: • Pin size a when it is free : 24 mm • Pin size b when it is contacted against the gear : 20 mm • Pin size c after it is inserted into the gear : 16 mm ¡ You must stop barring as soon as the positioning pin is inserted, otherwise the pin can be broken.

(2) Remove the plug (25) from the fuel injection pump, then remove the timing pin (26).

(3) Reverse the timing pin (26) mounting position, fit the timing pin groove to the pointer (27) in the pump, then tighten the plug (25) temporarily. ¡ If the pointer (27) tooth does not fit in the timing pin hole, adjust the tooth position by turning shaft of the fuel injection pump.

PC75UU-3

30-17 1

DISASSEMBLY AND ASSEMBLY

FUEL INJECTION PUMP

(4) Install the fuel injection pump assembly (23).

(5) Tighten the mounting nut (22).

9 Nut : 43 ± 6 Nm {4.38 ± 0.61 kgm} (6) Install the brackets (21) and (20).

(7) Assemble the washer (19), then tighten the nut (18). ¡ Use care in installing the washer and nut so that they may not fall into the case.

9 Nut: 12.5 ± 2.5 Nm {1.27 ± 0.25 kgm} ¡ Note that above is not the final torque value. ¡ The nut tightening torque must not the above specified value, otherwise the No. 1 compression top dead center positioning pin can be damaged.

(8) Disengage the No. 1 cylinder compression top dead center positioning pin (24).

(9) Remove the plug (25), reverse the timing pin (26) mounting position, then install the plug to the injection pump.

9 Plug : 14.7 Nm {1.5 kgm} (10) Re-tighten the drive nut (19) on the fuel injection pump.

9 Nut : 95 ± 10 Nm {9.7 ± 1.02 kgm} (11) Carry out the succeeding installation procedures in the reverse order to the removal. ¡ Adjust the fuel injection timing. For details, see TESTING AND ADJUSTING, Testing and adjusting fuel injection timeing.

30-18 2

PC75UU-3

DISASSEMBLY AND ASSEMBLY

CYLINDER HEAD

5. Tighten the cylinder head mounting bolts in the sequence shown to the right.

8 Supply engine oil (SAE15W-40) to the threaded portion and seat surface of the mounting bolts.

9 Cylinder head mounting bolt : 1st time : Tighten the bolts the order of 1 to i with tightening torque set at 90 ± 5 Nm {9.18 ± 0.51 kgm}.

2nd time : Tighten bolts 3, 6, q and r, in this order, with tightening torque set at 120 ± 5 Nm {12.24 ± 0.51 kgm}.

3rd time : (1) When tool A4 is used : Re-tighten bolts 1 to i by 90 ± 5°, in this order, using the angular tightening wrench (tool A4).

(2) When tool A4 is not used : Apply marking to bolts and head, then re-tighten bolts by 90 ± 5°.

6. Tighten the rocker arm assembly mounting bolt (28).

9 Rocker arm mounting bolt : 24 ± 4 Nm {2.45 ± 0.41 kgm} ¡ Adjust the valve clearance. For details, see TESTING AND ADJUSTING, Testing and adjusting valve clearance.

•

Refilling with water Fill water up to the specified level, start the engine to circulate coolant through the piping, then check the level again.

PC75UU-3

30-29 2

DISASSEMBLY AND ASSEMBLY

RADIATOR AND HYDRAULIC OIL COOLER

REMOVAL OF RADIATOR AND HYDRAULIC OIL COOLER ASSEMBLY b

Lower the work equipment completely to the ground, stop the engine, then relieve pressure in the hydraulic oil tank by gradually loosening the tank cap.

1. Drain the coolant.

2. Remove the counterweight assembly. For details, see REMOVAL OF COUNTERWEIGHT ASSEMBLY. 3. Remove the fan guard (1).

4. Remove the two clamps on the fuel control cable (2) from the radiator.

5. Disconnect the radiator side connection of the hydraulic oil cooler inlet hose (3) and outlet hose (4).

6. Disconnect the radiator side connection of the hydraulic oil cooler inlet hose (5) and outlet hose (6).

1

7. Remove the radiator mount bracket (7).

30-30 1

PC75UU-3

DISASSEMBLY AND ASSEMBLY

WORK EQUIPMENT R. H. PPC VALVE

REMOVAL OF WORK EQUIPMENT R. H. PPC VALVE ASSEMBLY (FOR BOOM AND BUCKET CONTROL) b

Lower the work equipment completely to the ground, stop the engine, then relieve pressure in the hydraulic tank by gradually loosening the tank cap.

1. Remove the operator seat.

2. Remove the boots (2) from the cover (1).

3. Shift the lever (3) up, then remove the two wiring (4). ¡ Check direction of the lever. ¡ Slide the cover (1) upward.

4. Remove the PPC valve assembly (5) mounting bolt, then remove the six hoses (6) by lifting the PPC valve assembly.

1 ¡ The wiring clamp is tightened together with the mounting bolt.

5. Remove the PPC valve assembly (5).

2

INSTALLATION OF WORK EQUIPMENT R. H. PPC VALVE ASSEMBLY (FOR BOOM AND BUCKET CONTROL) •

Carry out the installation in the reverse order to the removal.

1 9 Hose joint bolt : 39.2 ± 4.9 {4.0 ± 0.5 kgm} 2 ¡ If excessive play is recognized with the control lever, adjust the PPC valve. For details, see TESTING AND ADJUSTING , adjusting work equpment, swing PPC valve.

•

Refilling with oil (Hydraulic oil tank) Fill oil up to the specified level via the oil filler port, start the engine to circulate oil through the piping, then check the oil level again.

PC75UU-3

30-89 1

DISASSEMBLY AND ASSEMBLY

WORK EQUIPMENT AND SWING PPC VALVE

DISASSEMBLY OF WORK EQUIPMENT AND SWING PPC VALVE ASSEMBLY 1. Remove nut (1), then remove disc (2) and boot (3).

2. Remove joint (4). ยก Do not remove joint (4) unless it is to be replaced.

3. Remove bolts, then remove plate (5). ยก Do not remove joint (4) unless it is to be replaced.

4. Remove seal (6) and collar (7).

5. Pull out piston (8), and remove retainer (9), springs (10) and (11), and shim (12). ยก Spring (10) consists of two sets of two types of springs with different installed loads, so check the mounting position (oil pressure port) and mark with tags to prevent mistakes when installing.

6. Pull out valve (13) from body (14).

30-90 2

PC75UU-3

WORK EQUIPMENT AND SWING PPC VALVE

DISASSEMBLY AND ASSEMBLY

ASSEMBLY OF WORK EQUIPMENT AND SWING PPC VALVE ASSEMBLY 1. Assemble valve (13) to body (14).

2. Assemble shim (12) and spring (11) to valve (13). ¡ When assembling spring (11), set the end with the small coil diameter (inside diameter) at shim (12) end.

3. Assemble spring (10), retainer (9), and piston (8). ¡ The number of loops in the coil for spring (10) is different for each of the hydraulic ports below, so be careful when installing.

Position of port

Number of coil spring loops

P1,P2

9

P3,P4

10.5

2 Piston : Grease (G2-LI) ¡ When assembling piston (8), coat the outside of the piston and the inside of the hole in the body with grease.

4. Fit O-ring to collar (7) and assemble in body (14), then install seal (6).

5. Install plate (5).

3 Mounting bolt : 13.24 ± 1.47 Nm {1.35 ± 0.15 kgm} 6. Install joint (4).

2 Sliding portion of joint : Grease (G2-LI) 2 – 4 cc 2 Female thread of body : Thread tightener (LT-2) 3 Joint : 44.1 ± 4.9 Nm {4.5 ± 0.5 kgm} ¡ Keep strictly to the tightening torque.

2 Contact face of piston and dise: Grease (G2-LI) 0.3 – 0.8 cc each (4 points) 7. Assemble boot (3) and disc (2), and tighten with nut (1).

3 Nut : 112.8 ± 14.7 Nm {11.5 ± 1.5 kgm} ¡ After assembling the disc, adjust the height of the disc. For details, see TESTING AND ADJUSTING, Adjusting PPC valve.

PC75UU-3

30-91 2

DISASSEMBLY AND ASSEMBLY

HYDRAULIC CYLINDER

3. Piston rod assembly (1) Set the plunger (8) on the piston rod, assemble the nine balls (7), then fix them with the cap (6). ¡ Make sure that end of the plunger is somewhat slackened.

• Arm cylinder alone.

(2) Assemble the head assembly (2) to the piston rod (5).

(3) Assemble the piston assembly (6) to the piston rod (5).

(4) Set the piston rod assembly (3) on the tool U1.

(5) Tighten the nylon nut (4) using the tool U3.

8 Nylon nut : Liquid adhesive (Locktite 262 or equivalent) 9 Nylon nut : Cylinder name Boom Arm Bucket Offset Blade

Tightening torque 3.97 ± 0.4 Nm {405 ±40.5 kgm} 3.33 ± 0.33 Nm {340 ±34.0 kgm} 2.16 ± 0.22 Nm {220 ±22 kgm} 1.42 ± 0.14 Nm {145 ±14.5 kgm} 3.97 ± 0.4 Nm {405 ±40.5 kgm}

4. Cylinder assembly (1) Set the cylinder on the tool U1.

(2) Install the piston rod assembly (3). ¡ Drive in the piston rod completely.

PC75UU-3

30-113 1

DISASSEMBLY AND ASSEMBLY

HYDRAULIC CYLINDER

(3) Tighten the head assembly (2) using the tool U2 and hydraulic pump or power wrench.

9 Head assembly : Cylinder name Boom

980 ± 98 Nm {100 ± 10 kgm}

Arm

1,107 ± 78.4 Nm {113 ± 8 kgm}

Tightening torque

1st time

Bucket

: Tighten with 1,176 to 1,372 Nm {120 to 140 kgm} 2nd time : Loosen up to 0 Nm {0 kgm} 3rd time : Tighten with 392 Nm (40 kgm) 4th time : Angular tightening (rotation volume 3.5 to 4.5 mm at cylinder head outer perimeter)

Offset

931 ± 93.1 Nm {95 ± 9.5 kgm}

Blade

1,030 ± 103 Nm {105 ± 10.5 kgm}

30-114 2

PC75UU-3

MAINTENANCE STANDARD

SWING CIRCLE

SWING CIRCLE

Unit : mm

No.

Check item

1

Clearance between bearing and circle

PC75UU-3

Criteria

Remedy

Standard clearance

Clearance limit

0.3 â&#x20AC;&#x201C; 1.2

2.0

Replace

40-3 (4)