CG958G Wheel Loader. Manual - part 15

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1. Working oil cylinder, 2. Vane pump, 3. Pilot system, 4. Selector valve, 5. Right lift cylinder, 6. Left lift 

cylinder, 7. Tipping cylinder 

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The loader adopts pilot-controlled working hydraulic system with pilot oil coming from delivery side of 

steering pump. A locking electromagnetic valve is installed on pilot-controlled delivery valve which is 

powered off when not working. In this case, operation of pilot handle will not activate working unit for safety 

purpose. Under working status, the locking electromagnetic valve is powered on and the operation of pilot 

handle will activate the reversing of selector valve plug to realize lifting, lowering of working unit and bucket 

retracting and tipping, etc. 

Pilot system accumulator keeps the pressure at a certain level. In case of sudden breakdown of engine, place 

pilot handle to lowering position so that the hydraulic oil in accumulator applies a force on valve plug 

through pilot-controlled valve to lower the movable arms. 

Hydraulic components 

1. Working pump T6DM-B35-3L03-C1   

Working pump is a vane pump, refer to introduction in steering hydraulic system for its structure and 

operating principle. 

2. Pilot-controlled delivery valve 

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Structure and operating principle of pilot-controlled delivery pump are shown in the figure above. Ports P1 

and P2 are connected to pump source, port PR is connected to oil inlet of pilot-controlled valve while port PV 

serves as the pressure tap of pilot system. As the locking electromagnetic valve for pilot handle, when 

electromagnetic valve is powered off, there is no hydraulic oil pass through pilot system to prevent 

misoperation of handle from causing safety problems. 

3. Pilot-controlled valve: 7470 (2) 

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Pilot-controlled valve is a monolevered true motion relief valve integrating oil inlet, oil outlet, tipping port, 

retracting port, lifting port and lowering/floating port, etc. The position of pilot handle controls the travel of 

pilot-controlled valve plug, which is in proportion to the pressure at corresponding port to realize proportional 

hydraulic control over selector valve. Oil inlet of pilot-controlled valve is connected to port PR of 

pilot-controlled delivery valve for oil source. When the handle is turned to a certain angle, oil from port P 

enters corresponding valve plug end in selector valve and push the valve plug to achieve retracting, tipping, 

lifting and lowering operations. Electromagnet positioning is installed on pilot-controlled valve at lifting, 

retracting and floating positions. 

Note: in case of long-time shutdown, slight steering may be necessary after restarting to provide adequate 

supply pressure for pilot system before operating pilot handle to do lifting, retracting, tipping, lowering, etc.