Restriction Valve - Hitachi ZW180 Technical Manual

RESTRICTION VALVE

The restriction valve is installed at the inlet part to the
pilot circuit on the both ends of the spool for the lift arm.
If the pilot valve is tuned to the neutral position during
operation of the lift arm, the pilot pressure oil supplied
to the spool for the lift arm is drained through the
orifice of the check valve of the restriction valve.
Thereby, pilot pressure gradually decreases.
Therefore, shock to the body occurring during
operation of the front attachment can be reduced by
gradually returning the lift arm spool to the neutral
position.
COMPONENT OPERATION / Control Valve
Check Valve
Spool Side
T3-2-19
Orifice
Pilot
Valve Side
T4GB-03-02-014