NorAM 65E Turbo Motor Grader, Руководство по обслуживанию

Страница: 533 / 830

65E Turbo Motor Grader
Service Manual
8 - 1 Service 2.00_2013.03
Section 8
Hydraulics
Section 8: Hydraulics
G
ENERAL
The hydraulics supply the implements, steering, and cooling systems with oil flow to create movement. A
tandem pump is mounted to the auxiliary drive shaft of the transmission. One section supplies the fan motor.
The other section supplies the steering and main control valve.
The fan motor is protected with an adjustable pressure relief valve.
A load sense priority valve assures oil flow of 11 L/min (3.0 gpm) to the steering system. The remainder of
the oil enters the main control valve.
The main control valve has eight working sections plus inlet and outlet sections. The standard working sec -
tion is a three - way, three - position valve with parallel circuit. With no sections actuated, oil flows through an
open, neutral passage.
When a section is actuated, the open passage is closed and oil is routed through the pressure passage. A
check valve at each section prevents back
- feeding into other sections. Oil flow from the actuator (cylinder or
motor) enters the low pressure passage and returns to the reservoir.
Because of the parallel passage, multiple spools can be operated together if sufficient oil is available. Ori -
fices in the port fittings limit oil flow to all but the circle shift and side shift functions to ensure multiple func -
tion operation. An anti - cavitation valve is in circuits with vertical movement.
The inlet section incorporates a pressure relief cartridge set to 131 - 144 bar (1900 - 2100 psi).
Control levers are located in the cab for selecting the desired function through a series of linkages. Valve
spools are spring
- centered for return to neutral position.
If the motor grader is equipped with float, the sections controlling the moldboard height and front/ rear imple -
ments are three - way, four - position valves. The fourth position has a detent and allows oil to flow freely
between the rod and piston side of the cylinder.
Depending upon the level of options, a section may control two functions via a solenoid - operated valve. A
switch on top of the front console changes the outlet of the solenoid valve, sending oil to a different actuator.
The sections that may operate through a selector valve are the implement, saddle rotate and moldboard
pitch sections.
A filter is located in the return line to the reservoir. A bypass valve opens if the filter clogs.