Komatsu PC500LC-10R Shop Manual page 208

COMPONENT PARTS OF HYDRAULIC SYSTEM
Control of the discharged volume
1.
As the swash plate angle (a) is increased, the difference
between volumes (E) and (F) is increased. Accordingly, the
discharged volume (Q) is increased.
2.
Servo piston (13) changes the swash plate angle (a).
3.
Servo piston (13) moves in a linear reciprocating motion
corresponding to the signal pressure from the PC valve
and LS valve.
This linear reciprocating motion is sent to rocker cam (4)
through slider (14).
4.
The rocker cam (4) supported on the cylindrical surface of
cradle (2) slides and pivots on that surface.
5.
Output pressure (PEN) of LS valve is supplied to the pres-
sure chamber on large diameter piston side.
6.
The area of servo piston (13) for receiving the pressure
are not identical on the right side and left side. Main pump
discharged pressure (self-pressure) (PP) is always trans-
mitted to the pressure chamber of the small diameter pis-
ton side.
7.
The movement of the servo piston (13) is controlled by the
relationship of pressure between the small diameter piston
side (PP) and the large diameter side (PEN) and by the ra-
tio of the area receiving the pressure between the small di-
ameter piston and the large diameter piston.
MAIN PUMP LS VALVE
LS
Abbreviation for Load Sensing
10-114
10 STRUCTURE AND FUNCTION
PC500LC-10R