Operation & Maintenance Manual
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LG968 /969Wheel Loader
102
2 Hydraulic System
The hydraulic system includes the working equipment hydraulic system and steering hydraulic system.
The working equipment hydraulic system is composed of work pump, priority valve, multiway valve,
pressure selection valve, lift arm cylinder, bucket cylinder, hydraulic oil tank and pipe attachments, as
is shown in Figure 5-2.
The multi-way valve is changed from machinery control to hydraulic control multi-way valve. The
multiway valve of rocket cylinder controls three actions including dumping, median and taking
bucket back while the multiway valve of lift-arms cylinder controls four actions including floating,
lowering, median and lifting to achieve the control of loader’s working equipment. The hydraulic
control system employs hydraulic priority control technique, which is handy and flexible to control.
The pre-set pressure of safety valve is 18
～
18.5MPa. The overload pressure of rocket cylinder’s large
cavity is 20.5MPa while that of small cavity is 12MPa.
1-Working pump
2-Hydraulic reservoir
3-Pressure selection valve
4-Twin pump
5- Flow amplification valve 6-Steering cylinder 7-Steering unit 8-Pilot valve
9-Multiway valve rocket cylinder 11-Life-arms cylinder
12-Bucket cylinder
Figure 5-2 Hydraulic System Theory
This system employs flow amplification full hydraulic pin steering system. Flow amplification
steering system mainly includes steering pump, unload valve, flow amplification valve, steering unit,
steering cylinder, hydraulic oil reservoir and the pipe attachments.
