Kubota WSM STa-30, Workshop Manual

Page: 145 / 359

3-M8
ST
α
-30 · ST
α
-35, WSM TRANSMISSION
■
Charge Pump
It fills up the oil in the HST closing circuit. A part of oil
fed from charge pump flows to closing circuit through the
check and high pressure relief valve, and the other oil
flows into the case goes to the tank through the oil cooler.
W1016772
■
Charge Relief Valve
While pumped and filtered oil flows into the main oil
circuit through the check valves, excessive oil passes to
the case through the charge relief valve.
W1016898
■
Check and High Pressure Relief Valve
The check and high pressure relief valves monitor the
oil pressure in each line of the main oil circuit.
In neutral, both valves are open and charging oil
enters into the main oil circuit through the valves.
At normal operation, the check valve in the high
pressure side is closed and it pushes and opens the
another one.
When excessively high pressure is built up in one line,
the high pressure relief valve located in this line is open
and the oil flows into another line.
W1016970
■
Case Relief Valve
The case relief valve monitors the oil pressure in the
hydrostatic transmission case. When the oil pressure
rises, it opens and flows the oil directly to the
transmission case, so that the oil may not leak against
the sealing.
W1017082
(1) Charge Pump
(1) Spring (2) Poppet
(1) Check Valve Sheet
(2) Relief Poppet (3) Relief Spring
(4) Check Spring
(1) Poppet (2) Spring
KiSC issued 11, 2006 A