Komatsu PC20R-8 Shop Manual page 41

. If the discharge pressure rises further, the angle of
swash plate (4) becomes smaller. When this hap-
pens, the length of the arm applying total piston
force F1 is reduced from a to a', so a larger force
F1 is needed for the angle of swash plate (4).
. Is this way, curve P - Q becomes a curve (constant
horsepower control) which gives effective use of
the engine horsepower.
3. Load response control
. When carrying out load response control, the signal
pressure from the LS valve is transmitted to control
piston (8), and control piston (8) pushes swash
plate (4). The angle of swash plate (4) changes to
a point where this force is balanced with the total
force of the spring and piston, so the discharge
amount changes.
. Constant horsepower control is carried out with
priority over load response control, so the dis-
charge amount changes in the range below the
flow at constant horsepower control.
PC20R-8 PC27R-8
4
a'
Characteristics of (P-Q)
Max.
22
0 91
(93)
Discharge oil pressure P1 bar (kg/cm
4
8
F
1
RKP00090
206
(210)
2 )
RKP01311
SPRING
FORCE
RKP00111
10-23