Komatsu Galeo PC800-8 Shop Manual page 159

10 Structure, function and maintenance standard
2. Suction valve
Function
• If the fan pump stops, the hydraulic oil does not
flow into the motor. Since the motor continues
revolution because of the force of inertia, howev-
er, the pressure on the outlet side of the motor
rises.
• When the oil stops flowing in from inlet port P, the
suction valve sucks in the oil on the outlet side
and supplies it to the port MA where there is not
sufficient oil to prevent cavitation.
Operation
1) When pump is started
• If the hydraulic oil from the pump is supplied to
port P and the pressure on MA side rises and
starting torque is generated in the motor, the mo-
tor starts revolution. The oil on outlet MB side of
the motor returns through port T to the tank.
2) When pump is stopped
• If the engine is stopped and the input revolution
of the fan pump lowers to 0 rpm, the hydraulic oil
from the pump is not supplied to port P anymore.
As the hydraulic oil is not supplied to MA side of
the motor, the motor speed lowers gradually to
stop.
• If the motor shaft is revolved by the force of iner-
tia while the oil flow in port P is reducing, the oil
in port T on the outlet side is sent by the suction
valve to MA side to prevent cavitation.
PC800, 850-8
SEN00383-03
37