Komatsu PC500LC-10R Shop Manual page 328

COMPONENT PARTS OF SWING SYSTEM
CHECK VALVE, SHUTTLE VALVE, AND 2-STAGE SWING RELIEF VALVE OF
SWING MOTOR
FUNCTION OF CHECK VALVE, SHUTTLE VALVE, AND 2-STAGE SWING RELIEF
VALVE OF SWING MOTOR
• When the upper structure stops swinging, the motor outlet
circuit is closed by control valve (6), but the motor is turned
by the inertial force.
• If the motor outlet circuit pressure increases abnormally, it
may damage the motor.
• Abnormally high pressure is released from the motor outlet
(high-pressure side) to port (S) to prevent damage to the
motor.
10-234
10 STRUCTURE AND FUNCTION
PC500LC-10R