Reverse Rotation Control Valve - Hitachi ZW180 Technical Manual

COMPONENT OPERATION / Hydraulic Fan Motor

REVERSE ROTATION CONTROL VALVE

The fan motor rotates reversely by operations of the
reverse rotation control solenoid valve and the reverse
rotation spool.
Operation
•
Reverse Rotation Control Solenoid Valve in
Neutral
1. When reverse rotation control solenoid valve (1)
is in neutral, pressure oil (P) from the fan pump is
blocked by selection valve (2).
2. As reverse rotation spool (3) is pushed by spring
(4), pressure oil (P) from the fan pump flows to
port MB and the fan motor rotates normally.
•
Reverse Rotation Control Solenoid Valve in
Operation
1. When reverse rotation control solenoid valve (1)
is operated, pressure oil (P) from the fan pump
flows to the right end of reverse rotation spool (3)
through selection valve (2).
2. When pressure oil into the right end of reverse
rotation spool (3) overcomes the spring (4) force,
reverse rotation spool (3) moves to the left.
3. Pressure oil (P) from the fan pump flows to port
MA and the fan motor rotates reversely.
T3-3-8