Oil Flow - wsm STW37 Workshop Manual

STW34, STW37, STW40, WSM

[2] OIL FLOW

 When both solenoid valves are "OFF"
When both solenoid valves (7), (8) are "OFF", pressurized oil does not flow in bi-speed valve (2).
The piston in the hydraulic clutches (3), (5) are set at the left of figure by spring.
 When the solenoid valve (PTO) is turned "ON"
When the solenoid valve (8) is turned on, the pressurized oil flows to the PTO hydraulic clutch (3) through the
solenoid valve (8) . The clutch piston moves against the spring until the stroke end and power is transmitted to the
PTO shaft. Oil in the PTO hydraulic clutch (3) is kept pressured of 18.5 kg fixed.
To make the movement of the clutch piston smooth, the accumulator (4) is prepared for. The accumulator (4) is
built in HST case.
 When the solenoid valve (PTO) is turned "OFF"
When the solenoid valve (8) is turned off, the oil passage in the solenoid valve (8) changes, and oil in the PTO
hydraulic clutch (3) is drained to the transmission case through the solenoid valve (8) .
The clutch piston returns to left in figure by spring. The power to the PTO shaft is cut off.
 When the solenoid valve (Bi-speed) is turned "ON"
When the solenoid valve (7) is turned on, the pressurized oil gradually flows to the bi-speed hydraulic clutch (5)
through the solenoid valve (7) and orifice valve (6). The clutch piston moves against the spring at an appropriate
speed until the stroke end, and power of bi-speed is transmitted to the front wheel.
Oil in the bi-speed hydraulic clutch (5) is kept pressured of 18.5 kg fixed.
 When the solenoid valve (Bi-speed) is turned "OFF"
When the solenoid valve (7) is turned off, the oil passage in the solenoid (7) valve changes, and oil between the
solenoid valve (7) and orifice valve (6) is drained to the transmission case through the solenoid valve (7). At this time,
the orifice valve (6) moves up in figure by pressure difference. The oil in the bi-speed hydraulic clutch (5) is drained
promptly to the transmission case.
The clutch piston returns to left in figure by spring.
8-M9
HYDRAULIC SYSTEM
(1) Regulator Valve
(2) Bi-speed Valve
(3) PTO Hydraulic Clutch
(4) Accumulator
(5) Bi-speed Hydraulic Clutch
(6) Orifice Valve
(7) Solenoid Valve (Bi-speed)
(8) Solenoid Valve (PTO)
A: A Port (To Bi-speed
Hydraulic Clutch)
B: B Port
(To PTO Hydraulic Clutch)
P: P Port
(From Regulator Valve)
9Y1211109HYM0008US0
KiSC issued 11, 2014 A