Komatsu Galeo PC800-8 Shop Manual page 134

SEN00383-03
Control of delivery
• If the swash plate angle (a) becomes larger, the
difference between volumes (E) and (F) be-
comes larger and pump delivery (Q) increases.
• Swash plate angle (a) is changed with servo pis-
ton (8).
• Servo piston (8) moves in a reciprocal movement
according to the signal pressure from the pump
controller.
• This linear motion is transmitted to rocker cam
(4) through rod (19).
• Rocker cam (4) slides on the cylindrical surface
of cradle (2).
• With servo piston (8), the area receiving the
pressure is different on the left and the right. The
pump discharge pressure (self pressure) (PH) is
constantly led to the pressure chamber of the
small diameter piston end.
• The pressure chamber of the large diameter pis-
ton end is supplied with the VC valve output
pressure (PS).
12
10 Structure, function and maintenance standard
• The relationship in the size of pressure (PH) at
the small diameter piston end and pressure (PS)
at the large diameter piston end, and the ratio be-
tween the area receiving the pressure of the
small diameter piston and the large diameter pis-
ton controls the movement of servo piston (8).
PC800, 850-8