Hyundai R 160 LC-3, Service Manual

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When the left control lever manually is placed in the arm roll in position.
Then the oil flows from pilot pump through the remote control valve to arm sections of the main
control valve. Here, the spool positions are moved to arm roll in position.
The oil flows from both main pump through arm section of the main control valve to the bottom end
of the arm cylinder, and to roll in arm.
The return oil flows from the rod end of the cylinder through the arm1 section returned to the tank.
Then cavitation which will happen to the bottom of the arm cylinder is prevented by a make up valve,
on other hand. The excessive pressure is also prevented by an overload relief valve in the main
control valve.
3. ARM ROLL IN OPERATION
ARM1
TRAVEL MOTOR
ARM CYLINDER BOOM CYLINDER
SWING MOTOR
HYD
TANK
FRONT
PUMP REAR
PUMP PILOT
PUMP
P1 P2 R
XBa1
ARM2
BUCKRT CYLINDER
XBa2
XAa1
XBa2
XAa2
Pal
MAKE UP
VALVE RELIEF
VALVE
XAa2
XAah
ARM HALF SOLENOID VALVE
XAah