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CG958H Wheel Loader. Manual - part 16

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1.3.3 Description of steering hydraulic system

I. Principle:

II. Components:

1. Pump: T6DCM-B24-B05-3R23-C1

Manufacturer:

Denison USA

2. One-way valve: DIF-L32H

Manufacturer: Huade Hydraulic Parts Factory

. Emergency steering power unit: 12869-00

Manufacturer: Haldex Sweden

4. One-way valve: S25A02 0B

Manufacturer: Huade Hydraulic Parts Factory

5. Priority valve: VLE-150/882-5902-059

Manufacturer: Eaton

Steering gear

: BZZ1-1250（FK-0/20）550-7286/831-2604

Manufacturer: Eaton

Steering cylinder:

CL90X45/488 EG-00A

Manufacturer: Chengdu Hailingda Hydraulic Technology Co., Ltd.

III. System description

Pilot oil source

Brake pump

To Multi-way valve

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Steering system adopts a load-sensing hydraulic steering mechanism mainly consisting of

pump, load-sensing steering gear, priority steering control valve, steering cylinder, emergency

steering power unit, check valves and pipelines. LS pipeline transfers internal pressure signal from

steering gear to priority valve to achieve balance of the valve plug, thus ensuring the flow rate

required by port CF. When the pressure at the outlet of the steering pump is less than 8 bars, the

pressure switch installed at the outlet will close to drive the emergency steering power unit to

realize the function of emergent steering.

III. Description of Components
1.

Pump: Denison T6DCM-B24-B05-3R23-C1, position is shown in the figure below:

Denison vane pump meets SAE and IOS

standards. Hydrocushion design ensures long

service lives of shaft and bearing with extremely

small noise and high volumetric efficiency. The

main internal structure is as shown in the right

figure.

Outlet

Rotor

Vane

Inlet

Flow passage to

vane root

Figure 1

Continuous outlet pressure

nlet pressure or

outlet pressure

Figure 2

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IMPORTANT

Dismounting and servicing of vane pump by untrained maintenance staff is strictly
prohibited.

CAUTION

When replacing rubber tube assembly in vane pump, loader engine should be shut off

first to release pressure and cool down hydraulic oil (to a safe degree) before the

replacement is made.

2. Steering gear: Eaton BZZ-1250

static (splined connection)

a Operating principle: the functionality is realized by a load-sensing system. The flow rate

going through steering gear is quite low when steering gear is in neutral position to keep constant

pressure and save energy for the system. During power steering, pressure oil enters stator through

valve plug and valve bush, and pushes the rotor to rotate with steering wheel to transfer the oil

pressure to the left or right chamber of steering cylinder, thus realizing steering by pushing guide

wheel with cylinder piston rod. Oil in the other cylinder chamber returns to oil tank through steering

gear.

b Installation:

Make sure that steering gear installed is

coaxial to steering post with clearance kept in

axial direction to avoid dieback of valve plug.

Check steering wheel to see if opposite

rotation is smooth after installation.

c Pipelines should be installed as per

the four oil ports marked on steering gear:

“P” – to be connected with oil pump;

“T” – to be connected with oil tank;

“A” and “B” are to be connected with

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left and right chamber of steering cylinder respectively.

d Structure of steering gear is given in the right view:

e Diagram of FK combination valves:

Position of steering gear

IMPORTANT

1. Be careful not to bump or scratch the working surface or end surface of various parts.

2. Do not soak the dismounted rubber ring in gasoline to avoid deformation or deterioration due

to action between rubber and gasoline.

1 Safety valve plug, 2 Pad, 3 Valve body, 4 Pressure controlled valve plug of safety valve, 5 Spring, 6 Safety

valve assembly, 7 Overload valve plug, 8 Pad, 9 Overload valve seat, 10 Sealing ring, 11 Spring, 12 Overload

oil-supplying valve assembly, 13 Valve seat, 14 O-ring, 15 Inlet single-way valve assembly, 16 Locknut

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