Komatsu Galeo PC138US-8 Shop Manual page 123

10 Structure, function and maintenance standard
If port (E) and port (G) of the LS valve are con-
q
nected, the pressure entering the large diame-
ter end of the piston from port (J) becomes
drain pressure (PT), and servo piston (9)
moves to the right side.
The pump delivery will be set to the increasing
q
trend.
Accompanied with move of servo piston (9),
q
springs (4) and (6) will be expanded and the
spring force becomes weaker.
As the spring force is weakened, spool (3)
q
moves to the left, the connecting between port
(C) and port (D) is shut off and the pump dis-
charge pressure ports (B) and (C) are con-
nected.
As a result, the pressure on port (C) rises and
q
the pressure on the large diameter end of the
piston also rises. Thus, the rightward move of
servo piston (9) is stopped.
Servo piston (9) stop position (= Pump deliv-
q
ery) is decided by the position where the push-
ing force generated from the pressures (PP1)
and (PP2) applied to spool (3), the pushing
force of the solenoid in PC-EPC valve gener-
ates and the pushing force of springs (4) and
(6) are balanced.
PC138US, USLC-8
SEN02548-01
23