wsm STW37 Workshop Manual page 203

STW34, STW37, STW40, WSM
Charge Relief Valve
The charge oil flow the steering controller flows into
the main oil circuit through the check valves, excessive
oil passes to the case through the charge relief valve.
(1) Spring
(2) Poppet
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.
(1) Check Valve Sheet
(2) Relief Poppet
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.
(1) Poppet
Neutral Valve
The neutral valves in the main oil circuit lines are
open and pass the oil to the case when in neutral, and
the oil pressure in their lines becomes low. And when the
oil pressure in the high pressure line increases to a
specified pressure, the neutral valve closes.
(1) Spring Holder
(2) Spring
3-M8
TRANSMISSION
a: From the Steering
Controller and HST Oil
Filter
b: To the Check and High
Pressure Relief Valve
c: To the Case
9Y1211109TRM0008US0
(3) Relief Spring
(4) Check Spring
9Y1211109TRM0009US0
(2) Spring
9Y1211109TRM0010US0
(3) Poppet N
(4) Valve Body
9Y1211109TRM0011US0
KiSC issued 11, 2014 A