Hyundai R 160 LC-3, Service Manual

Page: 127 / 459

3 - 19
SWING CIRCUIT OPERATION
Sh
Pg
MAKE UP
PORT(Mu)
A B
TO/FROM MAIN CONTROL VALVE
PARKING BRAKE
BRAKE RELEASE VALVE
BRAKE OFF
BRAKE ON
MAKE UP VALVE
MOTOR BRAKE VALVE
dr3
SWING MOTOR DEVICE
MOTOR BRAKE VALVE
Motor brake valve for the swing motor limits to cushion the starting and stopping pressure of swing
operation.
MAKE UP VALVE
The make up valves prevent cavitation by supplying return oil to the vacuum side of the motor.
PARKING BRAKE
In case that the parking, of the machine at slope is required during operation, there is the danger of
involuntary swing caused by the self weight of the machine. The brake is connected to prevent this
involuntary swing.
PARKING BRAKE "OFF" OPERATION
The parking brake is released by the pilot pressure oil from the pilot pump.
When the left control lever placed in the swing position, the pilot pressure at the shuttle valve is
transferred to the brake release valve and the brake release valve is change over. Then the pilot
pressure lift the brake piston and release the parking brake.
PARKING BRAKE "ON" OPERATION
When the control lever placed in the neutral position, the pressure of the pilot oil passage down.
Then the brake release valve returned to the neutral position and the oil is returned from the brake
piston to the tank. And the brake is set to 'ON".
BYPASS VALVE
This bypass valve absorbs shocks produced as swing motion stops and reduced oscillation cause
by swing motion.
1)
2)
3)