Case TX742 TX842 TX945 Telehandlers Repair Manual 87684642 - PDF DOWNLOAD

REPAIR MANUAL

TELEHANDLERS TX742 TX842 TX945

ASN HHATX742N7HK74001~ HHATX842N7HK75001~ HHATX945N8HK76001~ 87684642 NA Issued 01Dec 07

5

SECTION 21 -- POWERSHIFT GEARBOX GEARBOX ASSEMBLY The gearbox comprises five main assemblies

2

3

1

4

5

TH121001

5 1. The converter 2. The input shaft and directional clutches: A – Reverse B – Forward

3. The output shaft with C (4th speed) and D (3rd speed) clutch assemblies 4. The lower shaft with E (1st speed) and F (2nd speed) clutch assemblies 5. The output shaft to the idler gear case

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6

SECTION 21 -- POWERSHIFT GEARBOX

GEAR AND CLUTCH POSITION F E

TH121002

6 Reverse (A)/Forward (B)

4th

1st speed (E)/2nd speed (F)

Output shaft with gear

Idler gear

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speed

(C)/3rd

speed (D)

SECTION 21 -- POWERSHIFT GEARBOX

7

IDLER GEAR CASE ASSEMBLY The idler gear case is mounted directly on the transmission. The sleeve (3) connects the transmission output shaft directly to the idler gear case input shaft (1). The front and rear axles are set in motion by the output shaft (2) via the drive shafts.

1

3

2

TH21R011

7 1. The input shaft

3. The connecting sleeve

2. The output shaft

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8

SECTION 21 -- POWERSHIFT GEARBOX

GEARBOX OPERATION Through the converter, the thermal engine transmits motion to the gearbox input shaft, on which the advance/reverse motion clutches are assembled.

Depending on the gearbox control lever selection, solenoid valves are energized/de--energized to enable oil

under pressure to engage the clutch packages corresponding to the selected direction and speed.

NOTE: For details, see the following pages.

TH121004

8 1.

Control pump converter and pressure adjusting valve

4.

Output shaft

2.

Input shaft and direction clutches (forward/reverse)

5.

Speed clutches

3.

Speed gears

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9

SECTION 21 -- POWERSHIFT GEARBOX Converter, pump control section and pressure adjustment valve Engine power is transmitted from the engine flywheel to the impeller through the impeller cover.

This element is the pump portion of the torque converter and is the primary component which starts the oil flowing to the other components which results in torque multiplication. This element can be compared to a centrifugal pump, that picks up fluid at its centre and discharges it at the outer diameter.

The torque converter turbine is mounted opposite the impeller and is connected to the turbine shaft of the torque converter. This element receives fluid at its outer diameter and discharges it at its centre.

The reaction member of the torque converter is located between and at the centre of the inner diameters of the impeller and turbine elements. Its function is to take the fluid which is exhausting from the inner portion of the turbine and change its direction to allow correct entry for recirculation into the impeller element. This recirculation will make the converter multiply torque.

The torque multiplication is function of the blading (impeller, turbine and reaction member) and the converter output speed (turbine speed). The converter will multiply engine torque to its designed maximum multiplication ratio when the turbine shaft is at zero RPM (stall).

Therefore we can say that as the turbine shaft is decreasing in speed, the torque multiplication is increasing.

The hydraulic pump is connected to the pump mechanism. The compressor hub gear drives this mechanism. Since the compressor hub gear is connected to the compressor cover, pump speed is directly related to engine speed.

NOTE: The pressure regulator valve is mounted behind the filter, in the filter adapter housing.

A B C

D E F

TH121005

9 Converter, pump control section and pressure adjustment valve.

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10

SECTION 21 -- POWERSHIFT GEARBOX

Input shaft and directional clutches The turbine shaft, driven by the turbine, transmits power to forward gear, at 4th speed or at reverse speed.

These clutches consist of a drum with internal splines and a bore to receive a hydraulically actuated piston. The piston is kept oil tight by the use of sealing rings. The steel discs with external splines, and friction discs with internal splines, are alternated until the required total is achieved.

A back--up plate is then inserted and secured with a retainer ring. A hub with outer diameter splines is inserted into the splines of discs with teeth on the inner diameter. The discs and hub are free to increase in speed or rotate in the opposite direction as long as no pressure is present in that specific clutch.

To engage the clutch, the solenoid will direct oil under pressure through tubes and passages to the selected clutch shafts.

Oil sealing rings are located on the clutch shafts.

These rings direct the oil through a drilled passage in the shaft to the desired clutch.

Pressure of the oil forces the piston and discs against the back--up plate. The discs with splines on the outer diameter clamping against discs with teeth on the inner diameter enables the drum and hub to be locked together and allows them to drive as one unit.

When the clutch is released, a return spring will push the piston back and oil will drain back via the solenoid, the bleed valve or holes in the clutch piston into the transmission sump.

These bleed valves will only allow quick escape of oil when the pressure to the piston is released.

The transmission is equipped with a reverse gear and two forward gears (forward and 4th gear): These speeds combined with a 3--speed clutch, produces a type of transmission with 4--forward gears and 3--reverse gears at different speeds.

The engagement of the directional clutches (forward and reverse) are modulated. This means that clutch pressure is built up gradually. This will enable the unit to make forward, reverse shifts while the vehicle is still moving and will allow smooth engagement of drive. The modulation is done hydraulically.

A B C

D E F

TH121006

10 The input shaft and directional clutches

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11

SECTION 21 -- POWERSHIFT GEARBOX The range clutches

The output section

Once a directional clutch is engaged power is transmitted to the range clutches (1st, 2nd or 3rd).

Operation and actuation of the range clutches is similar to the directional clutches.

The engagement of the range clutches is not modulated.

With a range clutch engaged, power is finally transmitted to the output shaft.

Output rotation is same as the engine rotation when the forward clutch is engaged.

A front axle disconnect is optional and is located on the output shaft. The drive to the front axle can be disconnected or connected by manual shifting.

A

A

B

B

C

C D

D

E

E F

F

TH121007

TH121008

11 The range clutches

12 The output section

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12

SECTION 21 -- POWERSHIFT GEARBOX

The transmission controls (refer to hydraulic diagram) The transmission is controlled by the direction and range solenoids. The solenoids are mounted on the left side of the transmission case. When the selected direction and range solenoids are energized, oil under pressure will flow through tubes and passages to the selected clutch shafts.

Oil sealing rings are located on the clutch shafts.

These rings direct oil under pressure through a drilled passage in the shaft to the desired clutch.

TH121009

13 The transmission controls R. Reverse gear solenoid valve T. Forward gear solenoid valve S. Splitter solenoid valve

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1.

2.

Solenoid valve (1) Solenoid valve (2)

13

SECTION 21 -- POWERSHIFT GEARBOX SOLENOID/CLUTCH COMBINATION The 6 transmission clutch packs are controlled by 5 solenoids, therefore combinations of between 1 and 3 activated solenoids are required for clutch engagement. These combinations are shown in the table below.

SOLENOIDS GEAR

R

T

S

CLUTCHPACKS 1

2

A

B

C

D

E

F

A4 A3 A2 A1 N R1 R2 R3 14 The clutches are engaged by hydraulic pressure and disengaged by spring.

The forward and reverse clutch packs are hydraulically modulated using a mechanical valve.

The other four speed clutches are not modulated during engagement.

Output is in the oposite direction to engine rotation.

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14

SECTION 21 -- POWERSHIFT GEARBOX

2 1

3 4 8 5 6

7

TH121010

15 Operating Valves and Solenoids 1. Forward Feathering Valve

5. Solenoid (S)

2. Reverse Feathering Valve

6. Solenoid (1)

3. Solenoid (R)

7. Solenoid (2)

4. Solenoid (T)

8. Housing

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SECTION 21 -- POWERSHIFT GEARBOX

15

TRANSMISSION AND HYDRAULIC OIL CIRCUIT DIAGRAMS NEUTRAL GEAR ENGAGED

A – Reverse clutch B – Forward clutch C – 4th speed clutch D – 3th speed clutch E – 1st speed clutch F – 2nd speed clutch

Operating solenoids: none

TH121011

16

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16

SECTION 21 -- POWERSHIFT GEARBOX

VR

VT

1

E

2

F

T

D

S

C

R

B

A

TH121012

17 Aspirated oil

Torque converter and lubrication oil [29 -- 101.5 psi (2 -- 7 bar)]

High pressure oil

Return to reservoir

[239.3 -- 280 psi (16.5 -- 19.5 bar)] VT Forward modulation valve

Pressure oil from the system regulating valve flows to the 1 solenoid and forward solenoid T. None of the solenoids are engaged, allowing the oil to flow through to the clutch D only.

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VR Reverse modulation valve

Clutches A, B, C, D, E and F are open to reservoir.

SECTION 21 -- POWERSHIFT GEARBOX

17

TRANSMISSION OPERATION FIRST GEAR ENGAGED

A – Reverse clutch B – Forward clutch C – 4th speed clutch D – 3th speed clutch E – 1st speed clutch F – 2nd speed clutch

Operating solenoids: T, 1 and 2 TH121013

18

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18

SECTION 21 -- POWERSHIFT GEARBOX

VT

1

E

2

F

T

D

S

C

VR

R

B

A

TH121014

19 Aspirated oil

Torque converter and lubrication oil [29 -- 101.5 psi (2 -- 7 bar)]

High pressure oil [239.3 -- 280 psi (16.5 -- 19.3 bar)] VT Forward modulation valve

Pressurized oil coming from the system regulation valve arrives at solenoid valve 1 and at the forward gear solenoid valve.

Solenoid valve 1 is energized and it enables system pressure to engage clutch E. At this point solenoid valve 2 is energized enabling pressurized oil possibly present in clutches D or F to be discharged into the sump.

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Return to reservoir VR Reverse modulation valve

The forward solenoid is energized allowing system pressure to flow through the splitter solenoid, to the forward B clutch. Modulation is controlled by the modulation valve in the circuit.

As pressure increases in the forward clutch line drive increases with smooth modulation.

Clutches A, C, D and F are open to the reservoir.

SECTION 21 -- POWERSHIFT GEARBOX

19

TRANSMISSION OPERATION SECOND GEAR ENGAGED

A – Reverse clutch B – Forward clutch C – 4th speed clutch D – 3th speed clutch E – 1st speed clutch F – 2nd speed clutch

Operating solenoids: T and 2 TH121015

20

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20

SECTION 21 -- POWERSHIFT GEARBOX

VT

1

E

2

F

T

D

S

C

VR

R

B

A

TH121016

21 Aspirated oil

Torque converter and lubrication oil [29 -- 101.5 psi (2 -- 7 bar)]

High pressure oil [239.3 -- 280 psi (16.5 -- 19.3 bar)] VT Forward modulation valve

Pressurized oil coming from the system regulation valve arrives at solenoid valve 1 and at the forward gear solenoid valve.

Solenoid valve 2 is energized enabling system pressure to engage clutch F. The forward solenoid is energized allowing system pressure to flow through the splitter solenoid, to the forward B clutch.

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Return to reservoir VR Reverse modulation valve

Modulation is controlled by the modulation valve in the circuit.

As pressure increases in the forward clutch line, drive increases with smooth modulation.

Clutches A, C, D and E are open to the reservoir.

SECTION 21 -- POWERSHIFT GEARBOX

21

TRANSMISSION OPERATION THIRD GEAR ENGAGED

A – Reverse clutch B – Forward clutch C – 4th speed clutch D – 3th speed clutch E – 1st speed clutch F – 2nd speed clutch

Operating solenoids: T TH121017

22

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22

SECTION 21 -- POWERSHIFT GEARBOX

VT

1

E

2

F

T

D

S

C

VR

R

B

A

TH121018

23 Aspirated oil

Torque converter and lubrication oil [29 -- 101.5 psi (2 -- 7 bar)]

High pressure oil [239.3 -- 280 psi (16.5 -- 19.3 bar)] VT Forward modulation valve

Pressurized oil coming from the system regulation valve arrives at solenoid valve 1 and at the forward gear solenoid valve.

Since neither solenoid valve 1, nor solenoid valve 2 are energized, pressurized oil can engage clutch D.

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Return to reservoir VR Reverse modulation valve

Forward gear T solenoid valve is energized and it enables oil to flow through the separation solenoid valve S. which is not energized, and from there to clutch B. Clutches A, C, E and F are open to the reservoir.

SECTION 21 -- POWERSHIFT GEARBOX

23

TRANSMISSION OPERATION FOURTH GEAR ENGAGED*

A – Reverse clutch B – Forward clutch C – 4th speed clutch D – 3th speed clutch E – 1st speed clutch F – 2nd speed clutch

Operating solenoids: T and S TH121019

24 * Except different specifications of foreign Countries

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24

SECTION 21 -- POWERSHIFT GEARBOX

VT

E

T

2

1

F

D

S

C

VR

R

B

A

TH121020

25 Aspirated oil

Torque converter and lubrication oil [29 -- 101.5 psi (2 -- 7 bar)]

High pressure oil [239.3 -- 280 psi (16.5 -- 19.3 bar)] VT Forward modulation valve

Pressurized oil coming from the system regulation valve arrives at solenoid valve 1 and at the forward gear solenoid valve.

Oil flows through solenoid valve 2 and engages the multi--disk clutch D.

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Return to reservoir VR Reverse modulation valve

Oil flows through forward gear T solenoid valve which is energized, then through separation solenoid valve S which is also energized, and which engages multi--disk C clutch.

Clutches A, B, E and F are open to the reservoir.

SECTION 21 -- POWERSHIFT GEARBOX

25

TRANSMISSION OPERATION REVERSE FIRST GEAR ENGAGED

A – Reverse clutch B – Forward clutch C – 4th speed clutch D – 3th speed clutch E – 1st speed clutch F – 2nd speed clutch

Operating solenoids: R, 1 and 2 TH121021

26

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26

SECTION 21 -- POWERSHIFT GEARBOX

VT

1

E

2

F

T

D

S

C

VR

R

B

A

TH121022

27 Aspirated oil

Torque converter and lubrication oil [29 -- 101.5 psi (2 -- 7 bar)]

High pressure oil [239.3 -- 280 psi (16.5 -- 19.3 bar)] VT Forward modulation valve

Pressurized oil coming from the system regulation valve arrives at solenoid valve 1 and at the forward gear solenoid valve.

Solenoid valve 1 is energized and enables system pressure to engage clutch E. At this point solenoid valve 2 is energized enabling pressurized oil possibly existing in clutches F and D to be discharged into the sump.

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Return to reservoir VR Reverse modulation valve

The forward solenoid is not energized allowing oil to flow through the reverse solenoid which is then energized. Oil flows to the reverse clutch. Modulation is controlled by the modulation valve in the circuit.

Clutches B, C, D and F are open to the reservoir.

SECTION 21 -- POWERSHIFT GEARBOX

27

TRANSMISSION OPERATION REVERSE SECOND GEAR ENGAGED

A – Reverse clutch B – Forward clutch C – 4th speed clutch D – 3th speed clutch E – 1st speed clutch F – 2nd speed clutch

Operating solenoids: R and 2 TH121023

28

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28

SECTION 21 -- POWERSHIFT GEARBOX

VT

1

E

2

F

T

D

S

C

VR

R

B

A

TH121024

29 Aspirated oil

Torque converter and lubrication oil [29 -- 101.5 psi (2 -- 7 bar)]

High pressure oil [239.3 -- 280 psi

Return to reservoir

(16.5 -- 19.3 bar)] VT Forward modulation valve

Pressurized oil coming from the system regulation valve arrives at solenoid valve 1 and at the forward gear solenoid valve.

Solenoid valve 1 is not energized and it enables oil at system pressure to continue towards solenoid valve 2.

At this point solenoid valve 2 is energized enabling oil to flow towards clutch F and opening clutch D at the same time towards the tank.

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VR Reverse modulation valve

The forward solenoid is not energized allowing oil to flow through the reverse solenoid which is then energized. Oil flows to the reverse clutch. Modulation is controlled by the modulation valve in the circuit.

Clutches B, C, D and E are open to the reservoir.

SECTION 21 -- POWERSHIFT GEARBOX

29

TRANSMISSION OPERATION REVERSE THIRD GEAR ENGAGED

A – Reverse clutch B – Forward clutch C – 4th speed clutch D – 3th speed clutch E – 1st speed clutch F – 2nd speed clutch

Operating solenoids: R TH121025

30

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30

SECTION 21 -- POWERSHIFT GEARBOX

VT

1

E

2

F

T

D

S

C

VR

R

B

A

TH121026

31 Aspirated oil

Torque converter and lubrication oil [29 -- 101.5 psi (2 -- 7 bar)]

High pressure oil [239.3 -- 280 psi (16.5 -- 19.3 bar)] VT Forward modulation valve

Pressurized oil coming from the system regulation valve arrives at solenoid valve 1 and at the forward gear solenoid valve.

Solenoid valve 1 is not energized and it enables oil at system pressure to flow towards solenoid valve 2.

Solenoid valve 2 is not energized and hence oil flows towards clutch D.

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Return to reservoir VR Revese modulation valve

The forward solenoid is not energized allowing oil to flow through the reverse solenoid which is then energized. Oil flows to the reverse clutch. Modulation is controlled by the modulation valve in the circuit.

Clutches B, C, E and F are open to the reservoir.

SECTION 21 -- POWERSHIFT GEARBOX

31

MODULATION VALVE OPERATION The modulation valve shown on the pages opposite consists of the following components: 1. Modulation Valve Housing 2. Modulation Sleeve 3. Accumulator Valve 4. Regulator Valve 5. Stop Pin The graph shows how the pressure increases in the clutch pack from the moment of solenoid activation (A) until maximum clutch pressure is achieved (F).

Diagram A Oil is just about to enter the modulation valves and both the accumulator and regulator valves are seated on the stop pins.

Diagram B Oil initially flows in to the bottom of the regulator valve and unseats the regulator valve. This momentarily sends a high pressure pulse to the clutch pack which takes up the freeplay between the clutch pack plates.

Diagram C

Diagram D When the top side of the regulator valve is full of pressurized oil the spring pressure pushes the regulator valve back to its seat. Pressure then begins to act on the bottom of the accumulator valve.

Diagram E The accumulator valve starts to move up the sleeve and as it does the oil pressure required to push it up becomes greater and greater as the opposing spring pressure increases. This gradual increase in pressure feathers the clutch plates into engagment.

The pressure increase stops when the accumulator hits the limit rod at the top.

Diagram F As the oil supply continues to the clutch pack excess flow is bled off via the regulator valve.

Diagram G When the supply of oil to the clutch pack is cut off the regulator valve seats on the bottom pin allowing oil to flow out the top of the regulator valve allowing the modulation valve to become seated.

Oil starts to flow through the small orifice in the regulator valve and equalizes the pressure on either side.

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32

SECTION 21 -- POWERSHIFT GEARBOX

B

A

F E

Pressure

Modulated pressure C

1

Clutch pressure 2

D

3 A

Time

TH121229

4 32 5

Modulated pressure

Clutch pressure

Zero Pressure (Reservoir) TH121230

33

B

C

1 2

2

3

3

4

4

5

5

TH121232

TH121231

34 87684642 - 11 - 2007

1

35

33

SECTION 21 -- POWERSHIFT GEARBOX

D

E

1

1

2

2

3

3

4

4

5

5

TH121233

TH121234

37

36

F

G

1

1

2

2

3

3

4

4

5

5

TH121235

TH121236

38

39 87684642 - 11 - 2007

34

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SECTION 21 -- POWERSHIFT GEARBOX

35

SECTION 21 -- POWERSHIFT GEARBOX TORQUE CONVERTER AND HEAT EXCHANGER HYDRAULIC OIL CIRCUIT 12

11

14 13

10 15

9

8 16 7

6

5

4

2

3 1 TH121027

40 Aspirated oil

Torque converter and lubrication oil [29 -- 101.5 psi (2 -- 7 bar)]

High pressure oil [239.3 -- 280 psi

Return to reservoir

(16.5 -- 19.3 bar)] 1. Transmission sump 2. Transmission breather

9. System pressure regulating valve 10. Safety valve (10 bar)

3. Suction filter

11. Oil cooler test port

4. Oil pump

12. Torque converter pressure

5. Pressure filter

13. Torque converter

6. Filter by pass valve

14. Torque converter temperature

7. To clutch pack solenoids

15. Lubrication galleries

8. Clutch pressure (240 -- 280 psi) (16.5 -- 19.5 bar)

16. Forward and reverse clutch lubrication

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36

SECTION 21 -- POWERSHIFT GEARBOX

TROUBLESHOOTING GUIDE

TROUBLESHOOTING PROCEDURES

The following information is presented as an aid to isolating and determining the specific problem area in a transmission that is not functioning correctly.

When troubleshooting a “transmission” problem, it should be kept in mind that the transmission is only the central unit of a group of related powertrain components. Proper operation of the transmission depends on the condition and correct functioning of the other components of the group. Therefore, to properly diagnose a suspected problem in the transmission, it is necessary to consider the transmission fluid, charging pump, torque converter, transmission assembly, oil cooler, filter, connecting lines, and controls, including the engine, as a complete system.

By analysing the principles of operation together with the information in this section, it should be possible to identify and correct any malfunction which may occur in the system.

The transmission (power shift with torque converter transmission) troubles fall into three general categories: 1. Mechanical problems.

2. Hydraulic problems.

3. Electrical problems.

In addition to the mechanical and electrical components, all of which must be in the proper condition and functioning correctly, the correct functioning of the hydraulic circuit is most important. Transmission fluid is the “life blood” of the transmission. It mus be supplied in an adequate quantity and delivered to the system at the correct pressures to ensure converter operation, to engage and hold the clutches from slipping, and to cool and lubricate the working components.

Stall test

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A stall test to identifies transmission, converter, or engine problems.

Use following procedure: 1. Put the vehicle against a solid barrier, such as a wall, and block the wheels.

2. Put the directional control lever in FORWARD (or REVERSE, as applicable).

3. Select the highest speed.

With the engine running, slowly increase engine speed to approximately one--half throttle and hold until transmission (converter outlet) oil temperature reaches the operating range.

ATTENTION Do not operate the converter at stall condition longer than 30 seconds at one time, shift to neutral for 15 seconds and repeat the procedure until desired temperature is reached.

Excesssive temperature 250 qF (120 qC) maximum will cause damage to transmission clutches, fluid, converter, and seals.

3

SECTION 25 -- FRONT AXLE OPERATION Engine power (1) is transmitted from the engine through the powershift transmission (2) and the drop box (3) to the front axle (4) via the drive shaft (5).

2

1

3

4 5

TH25R004

2

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4

SECTION 25 -- FRONT AXLE

TROUBLESHOOTING PROBLEM

CAUSE

REMEDY

Same noise for engagement and 1. Hub bearings damaged release

Replace damaged elements

Higher noise during engagement 2. Low oil level rather than release

Top up oil

3. Crown wheel and pinion worn

Check through the upper cover.

Replace worn crown wheel and pinion

4. Crown wheel and pinion bear- Replace damaged elements ings worn 5. Planetary hub or bearing worn Replace damaged elements

Noise under steering

6. Pinion ring nut loose

Check the crown wheel and pinion and respective bearings. If they are not damaged, tighten the ring nut

7. Only one pinion bearing worn

See remedy No. 4

8. Differential gears and/or planet- Replace damaged elements ary hubs damaged

“Popping” noise when changing 9. Universal joint damaged direction of travel.

10. Wheel loose

Check and replace the joint as shown in the vehicle handbook Check possible wheel hub disc and stud bolt damages. If needed, repla-ce damaged elements and tighten the nuts to prescribed torque

11. Steering pin seals, axle shafts Check and or steering pivots damaged elements 12. Differential case gears loose

replace

Check through the upper cover.

Replace damaged elements

13. Differential adjusting bushings See remedy No. 8 worn

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damaged

3

SECTION 27 -- REAR AXLE OPERATION DIAGRAM Engine power (1) is transmitted from the engine through the transmission (2) and the drop box (3) to the rear axle (4) via the drive shaft (5).

2

1

4

3 5

TH27R001

2

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4

SECTION 27 -- REAR AXLE

REAR DRIVE SHAFT Specifications Length (A) closed: . . . . . . . . . . . 54.2 in (1377 mm) Extension (B): . . . . . . . . . . . . . . . . . . . . 2.8 (72 mm)

TH127005

3

ATTENTION 1

Support the drive shaft with suitable device during removal.

Loosen the locking stud bolt (2) screws (1) to disconnect the drive shaft (3) front part. Make the same operation on the rear side and remove the drive shaft (3).

2

3

NOTE: Refer to Section 25 “FRONT AXLE” for drive shaft spider removal.

TH127004

4

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SECTION 35 -- HYDRAULIC SYSTEM

9

HYDRAULIC CIRCUIT ELECTRO--PROPORTIONAL VERSION TX842 -- TX945 (sheet 2)

1

15 19

18

TH35R469

7

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10

SECTION 35 -- HYDRAULIC SYSTEM

16

17

Location of main components of the hyudraulic system complete with: — steering — telescopic boom

4 14

1

15

9

21 3 7

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

HYDRAULIC PUMP HYDRO STEERING VALVE FOR STEERING MODE CONTROL TILT CYLINDER PRESSURE RELIEF VALVE RIGHT STABILIZER (optional) LEFT STABILIZER (optional) LEVELLING CYLINDER STABILIZERS AND LEVELLING CONTROL VALVE STABILIZERS AND LEVELLING CONTROL SWITCHES ATTACHMENT CONTROL PILOT VALVE TILT CYLINDER SWITCH COMPENSATION CYLINDER ATTACHMENT CONTROL VALVE TELESCOPIC EXTRACTION CYLINDER BOOM LIFT CYLINDER HYDRAULIC OIL TANK PARKING BRAKE ELECTROVALVE FRONT AXLE REAR AXLE

19 18 10

2

8

13

5

20 12

11

TH35R470

8

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SECTION 35 -- HYDRAULIC SYSTEM

11

COMPONENT OPERATION 2 Hydraulic pump The hydraulic pump (1) is a constant flow gear pump with a built--in divider valve (2) that divides the load sensing line delivery flow.

The pump moves at the speed of the engine and has a rated delivery flow of 34.3 gpm (130 lt./min) at an engine speed of 2500 rpm, at 3335.9 psi (230 bar).

It can work at temperatures ranging from --13 °F (25 qC) to + 176 °F (80 qC).

The pump input control (3) is direct type, without idle gears.

3 TH135011

1 9

Hydraulic schematic

4 1

3 LS

(170 Bar)

TH35R244

2 10

The hydraulic connections to the pump and flow divider valve are: 1.

2.

3.

4.

1

to the hydraulic distributor pump intake line load sensing line to power assisted circuit of steering system with reducing valve

4

3 TH135013

11 Delivery side divider valve The flow divider valve (2) mounted at the back of the hydraulic pump (1) ensures that a priority flow corresponding to the demand is always delivered to the steering circuit (priority circuit), while the remaining flow is transmitted to the telescopic boom activated by the distributor and to the auxiliary circuits (secondary circuit).

1.

2.

3.

4.

5.

6.

Housing Load sensing line connector Shim Spring Pin Plug

2 4

3 5 1

TH135014

6 12 87684642 - 11 - 2007

12

1

11

2

SECTION 35 -- HYDRAULIC SYSTEM

3

4

9

10

5

8

6

7

TH135015

13 Operation of the delivery side flow divider valve

To steering circuit

Steering circuit load sensing signal

To tool circuit 1.

2.

3.

4.

5.

6.

7.

8.

9.

10.

11.

Pin To loader arm circuit Hydraulic pump intake hole Steering/braking circuit Hole Load sensing connector

The load sensing divider valve ensures that a priority flow corresponding to the demand is always delivered to the steering circuit (priority circuit), while the remaining flow is transmitted to the tool circuit (secondary circuit).

At key--on, the pin in the load sensing valve is pushed to the left by a spring (8) enabling the pump flow to enter the valve through a hole (3) which ensures the delivery of the priority flow to the steering and braking system circuits. The pressure of the pump is also applied to the centre of the pin and transmitted to the left hand side of the pin through hole (10). The balancing hole (9) senses the pressure but works as a damper to prevent the pin from moving in an irregular manner.

Assuming that during engine starting the braking and steering circuits are not used, the load sensing line opens towards the reservoir and the pump pressure

Shim (if fitted) Spring Balancing hole Hole Plug

applied to the left hand side of the pin moves the pin to the right, thereby conveying the delivery flow to the loader arm circuit.

As soon as the steering wheel is rotated, the pressure generated in these circuits is sensed in the load sensing line and applied to the right hand side of the pin. When the combined effects of the load sensed and the force of the spring against the right hand side of the pin exceeds the pressure applied to the left hand side of the pin, the pin moves to the left, thereby increasing the flow delivered to the steering circuit.

Since the oil in the load sensing line flows through the steering motor adjustment holes before reaching the divider valve, the load sensing pressure is always proportional to the demand. This ensures that the valve transmits only the quantity of oil necessary to the steering circuit, while the rest of the pump’s output flow is routed to the loader arm circuit.

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SECTION 35 -- HYDRAULIC SYSTEM

13

Pressure reduction valve (version TX742) Pressure reduction valve regulates the pressure at 35 bar in the part of the circuit that supplies oil to the piloted hydraulic controls and the joystick.

TH35R268

14 1.

2.

3.

4.

Hydraulic diagram Piloting pressure pick--up Connection to PST of main control valve Powering for joystick Discharge to reservoir

4

1

2

3

TH33R247

15

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14

SECTION 35 -- HYDRAULIC SYSTEM

Pressure reduction valve (version TX842--TX945) Pressure reduction valve regulates the pressure at 35 bar in the part of the circuit that supplies oil to the piloted hydraulic controls and the joystick.

TH135088

16 1.

2.

3.

4.

Hydraulic diagram Piloting pressure pick--up Connection to PST of main control valve Powering for joystick Discharge to reservoir

TH135087

17

TH135089

18 Detail of ports of pressure reduction valve

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SECTION 35 -- HYDRAULIC SYSTEM

15

FRONT LOADER CONTROLS To lift, lower, retract and extend the boom move the lever (1): -- forward, to lower the arm; -- back, to lift the arm; -- leftward to retract the boom; -- rightward to extend the boom.

1

TH35R248

19 Pilot valve control ON--OFF It is composed, frontally, of two buttons: pressing button (2) on the right side, the attachment rotates downward; pressing the left side, the attachment rotates upward. Buttons (3 and 4) located respectively on the front and rear side of the pilot valve are available for auxiliary functions.

2

4

3

TH35R249

20 The bottom part of the power assisted control unit includes six hydraulic connections that go to the joystick as follows: x Return to reservoir orifice (T) x Four outlet holes (1--2--3 and 4) for proportional pressure, each of which is connected to each end of the slide valves of the lifting and tilting control distributor. x An inlet orifice for the oil supply at a pressure of 35 bar (P).

Each of the four outlet holes is equipped with small pistons with plungers that make it possible to apply a pilot pressure proportional to the movement of the joystick at the end of a pin and hence to move it by the extent necessary to activate it.

The joystick is connected to a tilting plate; both the joystick and the plate are movable above the control unit body.

When the joystick is used, the tilting plate moves over one of the piston and plunger assemblies to transfer the oil to the hydraulic distributor spools.

T

1

4

2 3

P

TH135090

21

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16

SECTION 35 -- HYDRAULIC SYSTEM

PILOT VALVE CONTROL ELECTROPROPORTIONAL To lift, lower, retract and extend the boom move the lever (1): -- forward, to lower the arm; -- back, to lift the arm; -- leftward to retract the boom; -- rightward to extend the boom.

1

TH35R250

22 It is composed of a swinging proportional switch (2) and two buttons (3) and (4). Swinging switch (2) provides the turning of the attachment downward when it is moved forward and the turning upward when it is moved backward. Buttons (3) and (4) are available for auxiliary functions. Under the load handling lever, button (5) is present having the function of cutting--off the transmission. The button keeps the transmission disconnected until it is released.

2

3 4

5

TH35R251

23 The bottom part of the power assisted control unit includes six hydraulic connections that go to the joystick as follows: x Return to reservoir orifice (T) x Four outlet holes (1--2--3 and 4) for proportional pressure, each of which is connected to each end of the slide valves of the lifting and tilting control distributor. x An inlet orifice for the oil supply at a pressure of 35 bar (P).

Each of the four outlet holes is equipped with small pistons with plungers that make it possible to apply a pilot pressure proportional to the movement of the joystick at the end of a pin and hence to move it by the extent necessary to activate it.

The joystick is connected to a tilting plate; both the joystick and the plate are movable above the control unit body.

When the joystick is used, the tilting plate moves over one of the piston and plunger assemblies to transfer the oil to the hydraulic distributor spools.

T

1

4

2

P

3 TH135090

24

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2

SECTION 35 -- HYDRAULIC SYSTEM

1

17

3 4

5

8

7

6

TH35R205

25 Hydraulic cylinders 1.

2.

3.

4.

5.

6.

7.

8.

Telescopic boom cylinder Section 1st branch Section 2° branch Section 3° branch

The hydraulic cylinders employed to operate the telescopic boom are shown in the figure.

Telescopic boom cylinder (1) is located inside the boom structure.

The compensation cylinder (7) is connected hydraulically to the tilt cylinder (8) and ensures the self--levelling of the load forks (5) during the boom lifting cycle.

Loading forks Lifting cylinder with balancing valve Compensation cylinder Tilt cylinder with balancing valve.

A safety feature characterising the boom cylinders is the presence of balancing valves that ensure that the cylinder stays locked in its position even in the event of hydraulic pipe failure. The cylinders fitted with these valves cannot be retracted if the engine is not running.

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18

SECTION 35 -- HYDRAULIC SYSTEM

BALANCING VALVES The balancing and load holding valves are installed on the piston side of the boom lifting, tilt and telescopic extension cylinders.

Operation of the balancing valves (load holding) -- See page to follow The balancing (load holding) valves installed on the boom lifting, tilt and telescopic extension cylinders ensure that the cylinder rod stays locked in its position even in the event of a hydraulic pipe failure. With this type of load holding valve, it is not possible to retract the cylinders when the engine is inoperative and without operating the control spools.

When a two--section telescopic boom is mounted, a centralized dual--action holding valve is installed, preventing the activation of the telescopic cylinder both on the piston side and the rod side, if the engine is inoperative.

A. Extending the cylinder When a cylinder with a balancing valve is extended, the oil flows from the control valve spool to port V2 and through check valve to port C2. The oil returning from the cylinder enters freely from port C1 and port V1 then to the tank through the control valve spool.

B. Load holding (in neutral) When the spool is in neutral, the back pressure generated in the circuit by the weight of the telescopic boom and the load keeps the load holding valve in its seat, preventing the retraction of the boom.

C. Retracting the cylinder When the cylinder must be retracted, the oil flows from port V1 to port C1, but the pressure of the oil discharged in port C2 is insufficient by itself to move the double pilot spool against the spring of the safety valve letting the cylinder retract. The pressure applied to the cylinder through ports V1/C1is then applied as pilot pressure also to the end face of the spool through the threads of the pilot screw. This pressure, together with the back pressure applied to spool C2, moves the spool against the action of the safety valve spring enabling the oil discharged from the cylinder to flow back into the tank.

TH1350070

26 Since it takes both the load sensing pressure applied to the face of the double pilot spool and the cylinder discharge pressure through port C2 to move the spool and let the oil discharged from the cylinder to flow back to the tank, it is clear that in the event of a cylinder hose failure, the balancing valve would close under the action of the spring, preventing the retraction of the cylinder. Similarly, should the engine be inoperative, but the controls are actuated, there will be no pressure at port V1/C1 to supplement the back pressure applied to port C2 moving the spool and letting the oil flow back to the tank.

D. Operation of the (shock) safety valve Should a cylinder be subject to a sudden load variation, as it may be caused, for instance, by a collision against a wall while driving with the telescopic boom extended, the sudden load variation applied to the cylinder is excessive. In such circumstance the pressure generated at discharge port C2 is sufficient to move the spool against the force of the safety valve spring and discharge the excess pressure into the tank, via the circuit relief valve in the hydraulic control valve element. As soon as the pressure is relieved, the safety valve closes and holds the cylinder in its position.

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A 1

2 V1

C1

SECTION 35 -- HYDRAULIC SYSTEM

19

B 3

4

V2

V1

C2

C1

V2

C2

kg

C

D

V1

C1

V1

V2

C2

C1

V2

C2

TH135028

27 Operation of balancing valve

A. B. C. D.

Return to reservoir

Counter--pressure oil

Static oil

Oil at pump pressure

1.

2.

3.

4.

Extension Load holding Retracting Circuit relief function

Pilot screw Double pilot spool Check valve Circuit relief valve

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20

SECTION 35 -- HYDRAULIC SYSTEM

POWER STEERING (OSPQ) The main components of the OSPQ are the control valve and the rotor assembly. The control valve is a revolving valve that modifies the alignment of the oil passages as it revolves, thereby activating the steering cylinders. The rotor assembly is under the control valve.

Its normal function is to work as a hydraulic motor to perform metering operations. In an emergency, without fluid power, it is only possible to perform short steering maneuvers while the vehicle continues moving over a short distance.

1.

2.

3.

L R P T LS

Pipe fitting flange Flange to fasten the power steering Housing for steering column Cylinder supply line, for rear axle Cylinder supply line, for front axle From pump Discharge line to reservoir Load sensing line

P

1

R

T

2 LS L

3

TH135025

28

The action generated by the steering wheel transmits pressure through the LS line to the divider valve on the pump, which, in its turn, gives priority to the power steering P line.

The steering stroke--end is controlled by shockless valves (A) redirecting the oil flow into discharge line T.

TH35R196

29

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SECTION 35 -- HYDRAULIC SYSTEM

39

TH35R267

50

PARKING BRAKE CONTROL CHECK VALVE AT 72.5 PSI (5 BAR) Check valve (1) has the function of having an engagement time of the parking brake.

Under normal operating conditions and without the use of the hydraulic functions, the pressure in the circuit is equivalent to 217.5 psi (15 bar). This valve provides a pressure increment on the circuit with a value of 72.5 psi (5 bar) so that the engagement time of the parking brake is equivalent to 3 seconds.

1

TH35R277

51

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40

SECTION 35 -- HYDRAULIC SYSTEM

CYLINDERS

2

1

3 4

5

8

7

6

TH35R205

52

7. Compensation cylinder 8. Tilt cylinder with balancing valve.

3. Section 2° branch 4. Section 3° branch

5. Loading forks 6. Lifting cylinder with balancing valve

1. Telescopic boom cylinder 2. Section 1st branch

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