Kobelco 80CS ACERA Tier 4 Crawler Excavator Shop Manual - PDF DOWNLOAD

SHOP MANUAL CRAWLER EXCAVATOR

80CS ACERA TIER 4

87480997 NA

Issued 01July 08

SECTION 3 - SYSTEMS

SECTION 3 - SYSTEMS

CHAPTER 2 - HYDRAULIC SYSTEM

CHAPTER 2 - HYDRAULIC SYSTEM

Standard Specification

1

4

32.85MPa

A-3

3

19

A-6

32.85MPa

2

A-7

A-4

32.85MPa

32.85MPa

A-1

A-5

8

9 24.5MPa

24.5MPa

A-2 22

16 18 15 17

2.5MPa

27.5MPa

27.5MPa

14 5 32.9MPa

32.9MPa

3.5MPa

7 13

20

32.9MPa

32.9MPa

10

10

6 12

32.9MPa

11

32.9MPa

32.9MPa

32.9MPa

21

DOZER UP DOZER DOWN

29.4MPa

YT01Z00074P1 01

Figure 1

GRAPHIC_1D

5-14810 NA

Issued 07-2008

Bur

2-5

SECTION 3 - SYSTEMS

SECTION 3 - SYSTEMS

CHAPTER 2 - HYDRAULIC SYSTEM

Pi1

M

D1

Dr

Pd1

CHAPTER 2 - HYDRAULIC SYSTEM

D2

NOTE: 1.This hydraulic circuit is used to add to following circuit.

P R2

Pb

DWG.NO YT01Z00074P1

Ps

REMARKS SK70SR-2 STD

Pr R1

Pr

Pr

S1

SK80CS-2 STD No. Name 50 51 52 53 54 55

MAIN PUMP

50

YT01Z00075P1 Part No. LF30V00004F1 YT01V00030F1 LF01V00007F1 LF01V00008F1 YR30V00020F1

Model No. iK18-8002 iK18D2-103 110-70-916 105-65-594 KB7100000T 16041-05000

54 E F G A C B DH DOZER A4 B4

52

HYD.TANK A5 BOOM

B5 SWING TRAVEL LEVER PARKING 1-2 SPEED LOCK BRAKE CHANGE OVER A3 A2 A1 SV-1 SV-1 SV-4

T 3.5MPa SOL/V BLOCK

P P1

53 55

51

T P

32.9MPa A9 B9

32.9MPa

B BOOM SWING A Pi3 Dr4

R3

b9

SWING

MAIN CONTROL VALVE

a9

BOOMSWING LEFT

BOOMSWING RIGHT

YT01Z00075P1 01

Figure 2

GRAPHIC_1D

2-6

Issued 07-2008

Bur

5-14810 NA

SECTION 3 - SYSTEMS

SECTION 3 - SYSTEMS

CHAPTER 2 - HYDRAULIC SYSTEM

CHAPTER 2 - HYDRAULIC SYSTEM

THIS PAGE IS BLANK FOR EDITING CONVENIENCE

5-14810 NA

Issued 07-2008

Bur

2-7

SECTION 3 - SYSTEMS

CHAPTER 2 - HYDRAULIC SYSTEM

HYDRAULIC CIRCUIT OPERATION Color Coding Standard For Hydraulic Blue :

Feed, drain circuit,

less than 0.34 MPa (50 psi)

Green :

Return, make-up circuit,

0.34~ 0.59 MPa (50~85 psi)

Purple :

Secondary pilot pressure,

0.59~3.5 MPa(85~508 psi)

Red :

Primary pilot pressure,

3.5~5.0 MPa (508~ 725 psi)

Orange :

Main pump drive pressure,

3.5~29.4 MPa (508~4270 psi)

Brown :

Load sensing pressure,

0~29.4 MPa (0~4270 psi)

Blue tone :

At valve selection

Red valve :

When proportional valve (reducing) is operating

Red solenoid :

In active and exciting

Displaying the flow circuit and standby circuit when operating.

Regarding the electrical symbols in this manual, refer to the electric circuit diagram.

Neutral Circuit

FLOW CONTROL VALVE

SAFETY LOCK LEVER AND PILOT CIRCUIT

(1)When the actuator is operated, the pressurized delivery oil from the pump flows via the opening of the meter-in of spool, and is fed to the actuator.

(1)Purpose To protect attachment from unexpected operation for safety.

(2)Principle Cut pressure source of pilot valve for operation.

(3)Operation After engine starts, push down the safety lock l ev e r, t h e s o l e n o i d v a l v e ( S V- 4 ) o f t h e proportional valve block (13) is functioned, and the pilot operation circuit is actuated.

PUMP CONTROL (1)Operation 1)Pump delivery oil is delivered from D1 port and flows into P port of C/V (2). This oil branches off to the flow control valve (A-1) and to P-T passage of each spool, and return to the tank.

This return oil flows via negative control orifice (A-2), and the negative control pressure is generated, and the oil flows from Pn port to Pi1 port of the pump. Consequently, the negative control pressure pushes the piston U (A-3). On the other hand, tank pressure is led from Pr port to Pb port of the pump, this pressure pushes piston (back pressure compensation) to the reverse direction of piston U (A-3).

The difference of thrust between two pistons pushes the piston rod (A-5). And the self pressure leads the power piston (A-6) to the power piston chamber (A-7). This motion of piston adjusts the tilting angle of swash plate in accordance with negative control pressure.

2-8

(2)Simultaneously, the working pressure of actuator, namely the load sensing pressure (hereinafter called LS pressure), is generated.

This LS pressure acts on the spring chamber of the flow control valve (A-1).

(3)Simultaneously, the pump delivery pressure is led to the opposite side of the spring chamber of the flow control valve.

(4)The pump pressure is regulated to become the "Load sensing pressure + spring force" with the flow control valve. In this way the differential pressure between the pump pressure and the LS pressure is kept constant. And the before and after differential pressure of meter-in and meter-o ut are kept constant.

Consequently, the flow rate in accordance with the opening area is fed to the actuator.

Issued 07-2008

Bur

5-14810 NA

SECTION 3 - SYSTEMS

SECTION 3 - SYSTEMS

CHAPTER 2 - HYDRAULIC SYSTEM

CHAPTER 2 - HYDRAULIC SYSTEM

1

4

32.85MPa

A-3

3

19

A-6

32.85MPa

2

A-7

A-4

32.85MPa

32.85MPa

A-1

A-5

8

9 24.5MPa

24.5MPa

A-2 22

16 18 15 17

2.5MPa

27.5MPa

27.5MPa

14 5 32.9MPa

32.9MPa

3.5MPa

7 13

20

32.9MPa

32.9MPa

10

10

6 12

32.9MPa

11

32.9MPa

32.9MPa

32.9MPa

21

DOZER UP DOZER DOWN

29.4MPa

YT01Z00074P1 01 Figure 3

GRAPHIC_1D

NEUTRAL CIRCUIT: SAFETY LOCK LEVER ON 5-14810 NA

Issued 07-2008

Bur

2-9

SECTION 3 - SYSTEMS

CHAPTER 2 - HYDRAULIC SYSTEM

Travel Circuit

TRAVEL MAIN CIRCUIT (RIGHT OPERATION)

TRAVEL MOTOR FUNCTIONS

(1)Operation

(1) Functions 1)Prevention from overrun on a slope 2)Shockless relief valve prevents sudden stop by inertia 3)High/Low 2 speed switching mechanism 4)Travel parking brake 5)Travel speed automatic switching mechanism TRAV EL FORWARD PILOT SIMULTA NEOUS OPERATION CIRCUIT (1)Operation 1)Start travel right and left at the same time with c o n t r o l l eve r, a n d t h e p i l o t p r o p o r t i o n a l secondary pressure is delivered through P/V (11) 2, 4 por ts, at the same time select higher pressure and the higher pressure is delivered through 5, 6 ports, then acts on low pressure sensors (SE9) (SE10).

2)Pilot proportional secondary pressure flows into a2, a3 ports of control valve (2), acts on travel spool, and switches main circuit.

3)The signal output by low pressure sensor is input to mechatro controller, and the output voltage of low pressure sensor is input to mechatro controller, and the engine speed is changed from 2200 rpm to 2400 rpm.

T R AV E L 2 S P E E D S O L E N O I D C O M M A N D CIRCUIT

With travel pilot operation, the travel speed is switched, and the oil delivered through D1 port of main pump passes through C/V P-A2, flows into P2 port of travel motor (4) through C port of swivel joint (9) allowing travel motor to perform the operation.

(Refer Components System: Travel Motor Function) T R AV E L M A I N C I R C U I T ( R I G H T A N D L E F T SIMULTANEOUS OPERATION) (1)Purpose 1. Control of travel deviation caused by different pressure loading (2)Operation As for the oil flow at simultaneous operation, the fo l l o w i n g e x p l a n a t i o n i s b a s e d o n t h e assumption, that the loaded pressure of right travel is higher than left. Before the oil flows through the right and left travel spools, and the oil flows into the travel motor (4) via A2, A3 ports, the oil from P por t flows via the pressure compensation valve (A). In this case, the right higher loading pressure acts on the pressure compensation valve (A), and the pressure narrows the opening of compensation valve.

Consequently, the travel deviation is controlled, because the left loading pressure increased, and the inflow rate is adjusted.

(1)Purpose Change travel motor speed with switch.

(2)Operation Press switches with rabbit and turtle marks on travel lever grips, and the solenoid (SV-3) of proportional valve block (13) is excited and is switched, and solenoid command is output by port A2 and sends to P port of travel motor (4), opens oil passage to high speed piston, the selfpressure is led to the swash plate and the swash plate is changed to high speed tilting angle (small tilting).

2-10

Issued 07-2008

Bur

5-14810 NA

SECTION 3 - SYSTEMS

SECTION 3 - SYSTEMS

CHAPTER 2 - HYDRAULIC SYSTEM

CHAPTER 2 - HYDRAULIC SYSTEM

1

4

32.85MPa

A-3

3

19

A-6

32.85MPa

2

A-7

A-4

32.85MPa

32.85MPa

A-1

A-5

8

9 24.5MPa

24.5MPa

A-2 22

16 18 15 17

2.5MPa

27.5MPa

27.5MPa

14 5 32.9MPa

32.9MPa

3.5MPa

7 13

20

32.9MPa

32.9MPa

10

10

6 12

32.9MPa

11

32.9MPa

32.9MPa

32.9MPa

21

DOZER UP DOZER DOWN

29.4MPa

YT01Z00074P1 01 Figure 4

GRAPHIC_1D

TRAVEL CIRCUIT: TRAVEL 2ND. SPEED OPERATION 5-14810 NA

Issued 07-2008

Bur

2-11

SECTION 3 - SYSTEMS

CHAPTER 2 - HYDRAULIC SYSTEM

Bucket Circuit

BUCKET DIGGING MAIN CIRCUIT

BUCKET DIGGING PILOT CIRCUIT

(1)Operation

(1)Operation Star t bu cke t digging operation, and pilot propor tional secondar y pressure is output through port (1) of right pilot V (10), and flows into C/V (2) b6 port, and switches bucket spool.

With pilot operation, the pressurized oil switches the bucket spool, and is fed into bucket cylinder H side through C/V (2) B6 port. And the return oil from cylinder R side flows into tank circuit from A6 port while being restricted by bucket spool.

AUTO ACCEL OPERATION (1)Principle Star t ope ra tin g with sign al o utp ut by low pressure sensor.

(2)Operation [Lever in neutral position] If the pilot primary pressure does not be detected for 4 seconds or more, even if the accel dial position is in maximum, the engine speed becomes 1200 r pm. In this case, this pilot pr imar y pressure was led from P1 por t of solenoid valve (13) to Pg port of control valve (2) when the control lever was in neutral position.

[Lever in operation position] With lever operation, the operation pressure of actuator is generated in the passage (B-2), and the pressure acts on the deceleration valve (B-1), and this valve is switched. Consequently, the pilot pressure, which is connected with the oil tank, is blocked, and the pressure is generated at sensor (SE39). These action returns engine speed to set speed of acceleration dial.

ENGINE OVERLOAD PREVENTION BY PUMP POWER SHIFT CONTROL (1)Operation 1)As the pump delivery pressure rises, the pressure (self-pressure) exer ted on control piston (C-1) of power shift is also raised, and when the pressure rises to the pressure which resists to the thrust of piston U (C-2) and piston (pressure compensation) (C-3), the piston is pushed back.

2)After the piston is pushed back to the position where piston U self-pressure balances the negative control pressure, the self-pressure pushes back piston rod (C-4) and is led to internal pressure of piston chamber (C-6) of power piston (C-5).

3)Then, the tilting angle becomes smaller and reduces the delivery flow rate of the pump, and it helps to prevent engine overload.

2-12

Issued 07-2008

Bur

5-14810 NA

SECTION 3 - SYSTEMS

SECTION 3 - SYSTEMS

CHAPTER 2 - HYDRAULIC SYSTEM

CHAPTER 2 - HYDRAULIC SYSTEM

1

4

32.85MPa

C-2

C-1

3

19

C-5

32.85MPa

2

C-6

C-3

32.85MPa

32.85MPa

B-1

C-4

8

9 24.5MPa

24.5MPa

22

16 18 15 17

2.5MPa

27.5MPa

27.5MPa

14 5 32.9MPa

32.9MPa

3.5MPa

7 13

20

32.9MPa

32.9MPa

10

10

6 12

32.9MPa

11

32.9MPa

32.9MPa

32.9MPa

21

DOZER UP DOZER DOWN

29.4MPa

YT01Z00074P1 01 Figure 5

GRAPHIC_1D

BUCKET CIRCUIT: BUCKET DIGGING OPERATION 5-14810 NA

Issued 07-2008

Bur

2-13

SECTION 3 - SYSTEMS

CHAPTER 2 - HYDRAULIC SYSTEM

Boom Circuit BOOM RAISE PILOT CIRCUIT (1)Operation 1)Star t boom raise operation, and pilot proportional secondary pressure from right pilot valve (10) is output through port (4), and acts on b5 port of C/V (2).

2)Then, the secondary pressure fed into C/V (2) b5 port switches boom spool.

BOOM MAIN CIRCUIT (1)Purpose Boom raise speed up (2)Operation 1)Pump delivery oil flows into P port of C/V (2) and is led to boom spool.

2)After passing through spool, the delivery oil pushes and open lock valve (D-1), passes through B5 port and holding valve (19), and then is fed to the head side of boom cylinder (5).

3)Simultaneously, the negative pressure of boom is transformed into load sensing pressure and acts on flow control valve (D-2). While keeping the differential pressure of pump deliver y pressure and LS pressure constant, the pump flow rate in accordance with the negative control pressure is decided.

NOTE: Hereinafter, LS is short for Load sensing.

4)Return oil from the rod side through A5 port of C/V passes through boom spool and boom p r e s s u r e c o m p e n s a t i o n va l ve ( D - 4 ) , a n d branches in oil that passes through boom spool and boom pressure compensation valve and returns to the tank and in oil returned to the tank through sub-bleed opening provided on spool without passing through pressure compensation valve (D-4).

2-14

Issued 07-2008

Bur

5-14810 NA

SECTION 3 - SYSTEMS

SECTION 3 - SYSTEMS

CHAPTER 2 - HYDRAULIC SYSTEM

CHAPTER 2 - HYDRAULIC SYSTEM

1

4

32.85MPa

32.85MPa

3

19 32.85MPa

2

32.85MPa

D-2

8

9 24.5MPa

24.5MPa

22

16 18 15 17

2.5MPa

27.5MPa

27.5MPa

14 5

D-1 32.9MPa

32.9MPa

3.5MPa

7

D-3 D-4

13

20

32.9MPa

32.9MPa

10

10

6 12

32.9MPa

11

32.9MPa

32.9MPa

32.9MPa

21

DOZER UP DOZER DOWN

29.4MPa

YT01Z00074P1 01 Figure 6

GRAPHIC_1D

BOOM CIRCUIT: BOOM RAISE (UP) OPERATION 5-14810 NA

Issued 07-2008

Bur

2-15

SECTION 3 - SYSTEMS

CHAPTER 2 - HYDRAULIC SYSTEM

This section describes the boom lower operation.

BOOM LOWER PILOT CIRCUIT (1)Operation 1)After boom down operation, pilot proportional secondary pressure is delivered from port 2 of right pilot valve (10), is branched out in 3 circuits and acts on a5 port of C/V (2), Pi1 port and PL port of boom holding valve (19) respectively.

2)And the proportional secondary pressure led to a5 port of C/V (2) switches boom spool. The proportional secondary pressure led to Pi1 port of C/V (2) releases the lock of boom lock valve.

And the proportional secondary pressure led to PL port of boom holding valve (19) releases holding valve.

BOOM LOWER MAIN CIRCUIT (1)Operation 1)Pump delivery oil flows into P port of C/V (2) and then flows into boom spool.

2)After passing through spool, the delivery oil is fed to the rod side of boom cylinder (5) through A5 port. Simultaneously, the loading pressure for boom down operation acts on flow control valve (E-1) as the load sensing pressure.

(See Components System: Control Valve.)

The flow is regulated in the pump delivery flow rate in accordance with the negative control pressure by keeping the differential pressure of pump deliver y pressure and load sensing pressure constant.

3)The return oil from the head side of boom cylinder (5) flows into B port of boom holding va l ve ( 1 9 ) r e l e a s e d by p il o t p r o p o r t i o n a l secondary pressure for boom down operation and then flows into B5 port of C/V (2) through A2 port.

4)The oil led through B5 port of C/V (2) reaches to boom lock valve, but because the lock valve is re lea sed by pilo t pr op or tio na l s eco nd ar y pressure for boom down operation, the oil flows into boom spool.

5)And the pressure oil is restricted by passing through orifice passage provided on boom spool, and returns to the tank through boom pressure compensation valve (E-2).

2-16

Issued 07-2008

Bur

5-14810 NA

SECTION 3 - SYSTEMS

SECTION 3 - SYSTEMS

CHAPTER 2 - HYDRAULIC SYSTEM

CHAPTER 2 - HYDRAULIC SYSTEM

1

4

32.85MPa

32.85MPa

3

19 32.85MPa

2

32.85MPa

E-1

8

9 24.5MPa

24.5MPa

22

16 18 15 17

2.5MPa

27.5MPa

27.5MPa

14 5 32.9MPa

32.9MPa

3.5MPa

7 E-2

13

20

32.9MPa

32.9MPa

10

10

6 12

32.9MPa

11

32.9MPa

32.9MPa

32.9MPa

21

DOZER UP DOZER DOWN

29.4MPa

YT01Z00074P1 01 Figure 7

GRAPHIC_1D

BOOM CIRCUIT: BOOM LOWER (DOWN) OPERATION 5-14810 NA

Issued 07-2008

Bur

2-17

SECTION 3 - SYSTEMS

CHAPTER 2 - HYDRAULIC SYSTEM

Swing Circuit 1. SWING LEFT PILOT CIRCUIT (1)Operation 1)Start swing left operation and pilot proportional secondary pressure through port (3) of left pilot valve (10) is output, and acts on low pressure sensor (SE40), and at the same time the pressure flows into a1 ports of C/V (2).

2)Then, the secondary pressure fed into C/V (2) a1 port switches swing spool.

SWING AUTO PARKING BRAKE (1)Purpose Swing lock and parking in neutral position (2)Principle Release only when required to operate mechanical brake.

(3)Operation 1)Usually, the swing parking solenoid (SV39) is excited by turning starter switch key "ON", and the parking brake is actuated. In this time the pilot primary pressure is not conducted.

SWING MAIN CIRCUIT (1)Operation Pump delivery oil flows into P port of C/V and is led to swing spool. The oil passed through spool flows through swing pressure compensation valve (F-1) and flows into A port of swing motor through A1 port of C/V (2), and consequently has the swing motor rotated counterclockwise. And simultaneously, the loading pressure for swing operation acts on flow control valve (F-2) as load sensing pressure and the flow is regulated in the pump delivery flow rate in accordance with negative control pressure by keeping the differential pressure to the pump deliver y pressure constant.

(See Components System: Control Valve.)

And for swing spool, the bleed opening for return oil from swing spool to the tank is not closed completely even when swing lever is fully manipulated.

SWING MOTOR FUNCTION (1)Anti-cavitation circuit of swing reduction gear (2)Shockless relief for swing anti-reaction

2)Only when operation secondary pressure during swing and arm digging operation acts on any of low pressure sensor (SE40, 41, 7), it release the excitation to swing parking SOL. 3)After 5 seconds when the pressure of low pressure sensor (SE40, 41) from swing operation has disappeared, the swing parking SOL (SV-1) is excited. And in case of arm in operation, at the same time when the pressure of pressure sensor ( S E 7 ) fo r a r m i n o p e r a t i o n h a s b e e n disappeared, the swing parking SOL (SV-1) is excited.

2-18

Issued 07-2008

Bur

5-14810 NA

SECTION 3 - SYSTEMS

SECTION 3 - SYSTEMS

CHAPTER 2 - HYDRAULIC SYSTEM

CHAPTER 2 - HYDRAULIC SYSTEM

1

4

32.85MPa

32.85MPa

3

19 32.85MPa

2

32.85MPa

F-2

8

9 24.5MPa

24.5MPa

22

16 18 15

F-1

17

2.5MPa

27.5MPa

27.5MPa

14 5 32.9MPa

32.9MPa

3.5MPa

7 13

20

32.9MPa

32.9MPa

10

10

6 12

32.9MPa

11

32.9MPa

32.9MPa

32.9MPa

21

DOZER UP DOZER DOWN

29.4MPa

YT01Z00074P1 01 Figure 8

GRAPHIC_1D

SWING CIRCUIT: SWING OPERATION (LEFT) 5-14810 NA

Issued 07-2008

Bur

2-19

SECTION 3 - SYSTEMS

CHAPTER 2 - HYDRAULIC SYSTEM

Arm Circuit ARM CONTROL PILOT CIRCUIT (1)Operation 1)Start arm in operation, and pilot proportional secondary pressure is output through port (4) of left pilot valve (10), and acts on low pressure sensor (SE7), and at the same time the pressure branches into 2 circuits and acts on Pi2 and b7 ports of C/V (2).

2)Then, the secondary pressure acted on C/V (2) b7 por t switches arm spool. And secondary pressure acted on Pi2 port of C/V (2) releases the arm lock valve.

RECIRCULATION FOR ARM-IN OPERATION AND MAIN CIRCUIT (1)Purpose Speed up of arm-in operation (2)Principle To have a part of return oil in arm-in operation confluxes with feed oil (3)Operation 1)Pump delivery oil flows into arm spool through P port of C/V (2). After passing through arm spool, flows through arm pressure compensation valve (G-1) and is fed to the rod side of arm cylinder (6) through B7 por t of C/V (2).

Simultaneously, the loading pressure for arm-in operation acts on flow control valve (G-3) provided in C/V (2) as the load sensing pressure.

(See Components System: Control Valve.)

The flow is regulated in the pump delivery flow rate in accordance with the negative control pressure by keeping the differential pressure of pump deliver y pressure and load sensing pressure constant.

2)On the other hand, the return oil from the head side of arm cylinder (6) flows through A7 port of C/V (2) and is led to arm spool through arm lock valve released by pilot proportional secondary pressure which acts on Pi2 port.

3)The return oil is branched into the 2 oil flows.

One returns to the tank while being restricted by passing through orifice passage provided on arm spool. Another is recirculated in arm cylinder feed pressure by boost check valve (G-2) for recirculation.

2-20

Issued 07-2008

Bur

5-14810 NA

SECTION 3 - SYSTEMS

SECTION 3 - SYSTEMS

CHAPTER 2 - HYDRAULIC SYSTEM

CHAPTER 2 - HYDRAULIC SYSTEM

1

4

32.85MPa

32.85MPa

3

19 32.85MPa

2

32.85MPa

G-3

8

9 24.5MPa

24.5MPa

22

16 18 15 17

2.5MPa

27.5MPa

27.5MPa

14 5 32.9MPa

32.9MPa

3.5MPa

7 13

20

32.9MPa

32.9MPa

10

10

6 12

32.9MPa

11

32.9MPa

G-2 G-1 32.9MPa

32.9MPa

21

DOZER UP DOZER DOWN

29.4MPa

YT01Z00074P1 01 Figure 9

GRAPHIC_1D

ARM CIRCUIT: ARM IN (DIGGING) OPERATION 5-14810 NA

Issued 07-2008

Bur

2-21

SECTION 3 - SYSTEMS

CHAPTER 2 - HYDRAULIC SYSTEM

This section describes the following operations.

ARM OUT PILOT CIRCUIT (1)Operation 1)Star t ar m out operation, and the pilot propor tional secondar y pressure is output through port (2) of left pilot valve (9), and acts on a7 port of C/V (2), and switches arm spool.

ARM OUT MAIN CIRCUIT (1)Operation 1)Pump the delivery oil flows into arm spool through P port of C/V (2). And the delivery oil flows through arm pressure compensation valve (H-1) and is fed to the rod side of arm cylinder (6) through A7 port of C/V (2).

2)2) Simultaneously, the loading pressure for arm operation acts on flow control valve (H-2) provided in C/V (2) as the load sensing pressure and the flow is regulated in the pump delivery flow rate in accordance with negative control pressure by keeping the differential pressure to pump pressure constant.

(See Components System: Control Valve.)

3)And, the return oil from H side of arm cylinder (6) is led to arm spool, and returns to the oil tank.

2-22

Issued 07-2008

Bur

5-14810 NA

SECTION 3 - SYSTEMS

SECTION 3 - SYSTEMS

CHAPTER 2 - HYDRAULIC SYSTEM

CHAPTER 2 - HYDRAULIC SYSTEM

1

4

32.85MPa

32.85MPa

3

19 32.85MPa

2

32.85MPa

H-2

8

9 24.5MPa

24.5MPa

22

16 18 15 17

2.5MPa

27.5MPa

27.5MPa

14 5 32.9MPa

32.9MPa

3.5MPa

7 13

20

32.9MPa

32.9MPa

10

10

6 12

32.9MPa

11

32.9MPa

H-1 32.9MPa

32.9MPa

21

DOZER UP DOZER DOWN

29.4MPa

YT01Z00074P1 01 Figure 10

GRAPHIC_1D

ARM CIRCUIT: ARM OUT (EXTEND) OPERATION 5-14810 NA

Issued 07-2008

Bur

2-23

SECTION 3 - SYSTEMS

CHAPTER 2 - HYDRAULIC SYSTEM

Dozer Circuit DOZER UP PILOT CIRCUIT (1)Operation 1)After dozer up operation, the pilot proportional secondary pressure flows out through B port of dozer pilot valve (12), and acts on b4 port of C/V and switches the dozer spool.

DOZER UP MAIN CIRCUIT (1)Operation 1)Pump deliver y oil flows into dozer spool through P port of C/V (2). After passing through spool, the oil is fed to the rod side of dozer cylinder (8) through F port of swivel joint (9) from B4 port of C/V (2).

2)Simultaneously, the loading pressure for dozer operation acts on flow control valve (I-2) provided in C/V (2) as the load sensing pressure and the flow is regulated in the pump delivery flow rate in accordance with negative control pressure by keeping the differential pressure to pump pressure constant.

(See Components System: Control Valve.)

3)On the other hand, the return oil from the head side of dozer cylinder (8) flows to A4 port of C/V (2) through G port of swivel joint (9), and passes through spool and dozer pressure compensation valve (I-1) and returns to the oil tank through Pr port.

2-24

Issued 07-2008

Bur

5-14810 NA

SECTION 3 - SYSTEMS

SECTION 3 - SYSTEMS

CHAPTER 2 - HYDRAULIC SYSTEM

CHAPTER 2 - HYDRAULIC SYSTEM

1

4

32.85MPa

32.85MPa

3

19 32.85MPa

2

32.85MPa

I-2

8

9 24.5MPa

24.5MPa

22

16 18 15 17

2.5MPa

27.5MPa

27.5MPa

14 5

I-1 32.9MPa

32.9MPa

3.5MPa

7 13

20

32.9MPa

32.9MPa

10

10

6 12

32.9MPa

11

32.9MPa

32.9MPa

32.9MPa

21

DOZER UP DOZER DOWN

29.4MPa

YT01Z00074P1 01 Figure 11

GRAPHIC_1D

DOZER CIRCUIT: DOZER RAISE (UP) OPERATION 5-14810 NA

Issued 07-2008

Bur

2-25

SECTION 3 - SYSTEMS

CHAPTER 2 - HYDRAULIC SYSTEM

Boom Swing Circuit BOOM LEFT SWING PILOT CIRCUIT 1. Operation 1)Boom left swing operation, and the pilot propor tional secondar y pressure is output through port (4) of left pilot valve (55), and acts on a9 port of C/V (51), and switches arm spool.

BOOM LEFT SWING MAIN CIRCUIT 1. Operation 1)Pump the delivery oil flows into boom swing spool through P por t of C/V (50). And the d e l i ve r y o i l f l o w s t h r o u g h a r m p r e s s u r e compensation valve (K-1) and is fed to the head side of boom swing cylinder (53) through B9 port of C/V (51).

2)Simultaneously, the loading pressure for boom left swing operation acts on flow control valve (K2) provided in C/V (50) as the load sensing pressure and the flow is regulated in the pump delivery flow rate in accordance with negative control pressure by keeping the differential pressure to pump pressure constant.

(See Components System: Control Valve.)

3)And, the return oil from rod side of boom swing cylinder (53) is led to boom swing spool, and returns to the oil tank.

2-26

Issued 07-2008

Bur

5-14810 NA

SECTION 3 - SYSTEMS

SECTION 3 - SYSTEMS

CHAPTER 2 - HYDRAULIC SYSTEM

Pi1

M

D1

Dr

Pd1

CHAPTER 2 - HYDRAULIC SYSTEM

D2

NOTE: 1.This hydraulic circuit is used to add to following circuit.

P R2

Pb

DWG.NO YT01Z00074P1

Ps

K-2

REMARKS SK70SR-2 STD

Pr R1

Pr

Pr

SK80CS-2 STD S1

No. 50 51 52 53 54 55

MAIN PUMP

50

Name Control valve assy Control valve Boom cylinder Swing cylinder Dozer cylinder Pilot valve

YT01Z00075P1 Part No. LF30V00004F1 YT01V00030F1 LF01V00007F1 LF01V00008F1 YR30V00020F1

Model No. iK18-8002 iK18D2-103 110-70-916 105-65-594 KB7100000T 16041-05000

54 E F G A C B DH DOZER A4 B4

52

HYD.TANK A5 BOOM

B5 SWING TRAVEL LEVER PARKING 1-2 SPEED LOCK BRAKE CHANGE OVER A3 A2 A1 SV-1 SV-1 SV-4

T 3.5MPa SOL/V BLOCK

P P1

53 55

51

T P

32.9MPa A9 B9

32.9MPa

B BOOM SWING A Pi3 Dr4

R3

SWING

b9

a9

BOOMSWING LEFT

K-1

MAIN CONTROL VALVE

BOOMSWING RIGHT

YT01Z00075P1 01

Figure 12

GRAPHIC_1D

BOOM SWING CIRCUIT: BOOM SWING OPERATION (LEFT) 5-14810 NA

Issued 07-2008

Bur

2-27

SECTION 3 - SYSTEMS

CHAPTER 2 - HYDRAULIC SYSTEM

Combined Circuit BOOM UP, TRAVEL, AND MAIN CIRCUIT (1)Purpose During the simultaneous operation of travel and other attachment, the large speed variation and the deviation do not occur.

(2)Principle The pressure compensation valve of lighter load actuator functions, and controls the flow by regulating the loading pressure.

(3)Operation Pump delivery oil flows into P port of C/V (2) and is led to boom and right and left travel section.

We explain the case where the loading pressure for boom up operation is high on that occasion.

First, the loading pressure for boom operation acts on right and left travel compensation valves (L-1, L-2). Consequently the oil which passes through travel spool and flows into travel motor (4) through A2 and A3 ports is restricted by travel pressure compensation valves (L-1, L-2) and is r a i s e d t o t h e l o a d i n g p r e s s u r e fo r b o o m operation, and then the oil quantity fed to travel motor (4) reaches uniformity and the deviation is restrained.

But the travel spool is provided with notch which leads the oil to A2 and A3 por ts of C/V (2) w i t h o u t p a s s i n g t h r o u g h t r ave l p r e s s u r e compensation valves (L-1, L-2). The travel and boom (ATT) speeds are controlled by connecting to this passage.

2-28

Issued 07-2008

Bur

5-14810 NA

SECTION 3 - SYSTEMS

SECTION 3 - SYSTEMS

CHAPTER 2 - HYDRAULIC SYSTEM

CHAPTER 2 - HYDRAULIC SYSTEM

1

4

32.85MPa

32.85MPa

3

19 32.85MPa

2

8

32.85MPa

9 24.5MPa

24.5MPa

A-2 22

16 18 15 17

2.5MPa

L-1

L-2 27.5MPa

27.5MPa

14 5 32.9MPa

32.9MPa

3.5MPa

7 13

20

32.9MPa

32.9MPa

10

10

6 12

32.9MPa

11

32.9MPa

32.9MPa

32.9MPa

21

DOZER UP DOZER DOWN

29.4MPa

YT01Z00074P1 01 Figure 13

GRAPHIC_1D

COMBINED OPERATION: BOOM RAISE (UP) / TRAVEL SIMULTANEOUS OPERATION IN TRAVEL STRAIGHT FUNCTION 5-14810 NA

Issued 07-2008

Bur

2-29

SECTION 3 - SYSTEMS

SECTION 3 - SYSTEMS

CHAPTER 2 - HYDRAULIC SYSTEM

CHAPTER 2 - HYDRAULIC SYSTEM

NOTES

2-30

Issued 07-2008

Bur

5-14810 NA

KOBELCO CONSTRUCTION MACHINERY AMERICA, LLC. 245 E NORTH AVENUE CAROL STREAM, IL 60188 U.S.A.

North American English Part Number 87480997 NA Printed in U.S.A. • Bur