Transmisson Regulator Valve - Hitachi ZW180 Technical Manual

COMPONENT OPERATION / Drive Unit
TRANSMISSION REGULATOR VALVE
The transmission regulator valve controls pressure oil
from the charging pump in order to be constant
pressure, and supplies it to the transmission control
valve for controlling the clutch.
Pressure oil entering port P of the regulator valve from
the charging pump passes the small hole of the
regulator spool, and enters the back chamber of the
spool. When oil pressure in the back chamber
becomes higher than the spring force, the regulator
spool moves to the right, and pressure oil at port P
flows from the outlet port to the torque converter. This
movement of the spool keeps pressure at port P
constant. Port P is connected to the transmission
control valve, and pressure oil of a constant pressure
is supplied to the transmission control valve. Pressure
oil from port P passes the oil passage in the
transmission case, and is supplied to the transmission
control valve. Overflowing oil passes the oil passage in
the transmission case, and is supplied to the torque
converter.
T3-9-26