Komatsu Galeo PC138US-8 Shop Manual page 149

10 Structure, function and maintenance standard
Basic principle
1. Pump swash plate angle control
The pump swash plate angle (pump delivery)
q
is controlled so that LS differential pressure
( P L S ) ( t h e d i ff e r e n c e b e t w e e n p u m p
pressure PP and control valve outlet port LS
pressure PLS) (load pressure of actuator) is
constant.
[LS differential pressure ( PLS) = Pump
q
discharge pressure (PP) — LS pressure (PLS)]
PC138US, USLC-8
1
The pump swash plate angle shifts toward the
q
maximum position if LS differential pressure
( PLS) is lower than the set pressure of the
LS valve (when the actuator load pressure is
high).
If it becomes higher than the set pressure
q
(when the actuator load pressure is low), the
pump swash plate angle shifts toward the
minimum position.
LS differential pressure ( PLS) and pump
swash plate angle
a For details of functions, see the "Hydraulic
pump" paragraph.
SEN02549-02
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