Komatsu PC20R-8 Shop Manual page 52

3. When opening area of control valve is small (small movement of lever)
4
P
LS
LS valve
c
d
When engine is at high idling
. When the control lever is operated in small move-
ments, or when it is operated to the HOLD position
(in other words, when the area of opening of the
control valve becomes smaller), the difference be-
tween pump pressure P
other words, LS pressure DP
. When this happens, the movement is the same as
for "1. When control valve is at HOLD position":
pump pressure P
P
( ), so servo piston (4) is moved to the right
( ) in the direction of the minimum swash plate
angle.
In other words, the LS set differential pressure of
10-34
G
P
H
P
b
6
G
L
6
e
and LS pressure P
P
) becomes larger.
LS
pushes piston (6) to the left
the LS valve is taken as 16 bar (16 kg/cm
In the range from the neutral position of the control
valve to the small area of opening of the control
valve (fine control), in the area where LS differential
(in pressure DP
LS
pump swash plate angle moves in the minimum di-
rection. If the area of opening of the control valve is
further increased, and LS differential pressure
DP goes below 16 bar (16 kg/cm
LS
swash plate angle is moved in the maximum direc-
tion.
M
Control valve
P
P
G G
L
H
is more than 16 bar (16 kg/cm
LS
PC20R-8 PC27R-8
To actuator
P
LS
RKP01281
2
).
2
), the
2
), the pump