Charge-Cut Spool - Hitachi ZW180 Technical Manual

COMPONENT OPERATION / Ride Control Valve

CHARGE-CUT SPOOL

The charge-cut spool accumulates the operating
pressure for the lift arm cylinder in the ride control
accumulator, and shuts down the operating pressure
from the lift arm cylinder when the ride control
accumulator pressure is accumulated to the set
pressure.
1. When the ride control is not operated, pressure oil
at the lift arm cylinder bottom side flows to port X
through port A and the orifice.
2. Pressure oil into port X flows to the spool of the
charge-cut spool, opens the check valve, flows to
port Y and is accumulated in the ride control
accumulator.
3. As spool sectional area M is larger than spool
sectional area
accumulator pressure is accumulated to the set
pressure, pressure oil from port X pushes the
spool toward the spring.
4. When the spool moves toward the spring, the
passage of pressure oil from the spool to port Y is
closed, and accumulating the ride control
accumulator pressure is stopped.
N, when the ride control
T3-8-6