Komatsu F30791, Shop Manual

Page: 78 / 298

2) Boom swing, blade valve
. When boom swing spool (1) is operated, pump
pressure P
P
is reduced byreducing valve (3) (in
the same wayas in item 1), and is sent to the LS
circuit P
LS
.
. When the blade spool (5) is operated, pump pres-
sure P
P
flows from flow control valve (2), passage
e , and notch a in blade spool (5) through bridge
passage b to actuator circuit A .
. At the same time, the actuator circuit pressure
passes through notch f in hammer spool (6), then
goes through passage d , and acts on the left end
of piston (7). Piston (7) and reducing valve (3) then
move to the right.
. As a result, pump pressure P
P
is reduced at notch
d , becomes the actuator circuit pressure, and is
sent to LS circuit P
LS
.
M The boom swing and blade valves are different
from the boom, arm, bucket, and travel valves:
theyshare one pressure compensation valve
and bring in the LS pressure.
10-60
PC20R-8 PC27R-8
RKP00620
7
1 3
T
e
d
d
2
6
f
5
A
b
a
P
LS
P
P
4