1. Unload valve
FUNCTION
1) When the control valve is at HOLD, pump discharge amount
Q
discharged bythe minimum swash plate angle is
released to the tank circuit. When this happens, pump discharge pressure
P
P
is set to 16 bar (16 kg/cm
2
) by
spring (2) inside the valve.
(
LS
pressure
P
LS
=0 bar (0 kg/cm
2
)
OPERATION
When control valve is at HOLD
.
At the left end of spool (1), pump pressure
P
P
is act-
ing on area
S1
, and at the right end of spool (1),
pump pressure
P
P
is acting on area
S2
, and
LS
pressure
P
LS
is acting on area
S3
.
.
When the control valve is at HOLD,
LS
pressure
P
LS
is not generated, so onlypump discharge
P
P
has anyeffect, and
P
P
is set bythe load of spring
(2).
.
As pump discharge pressure
P
P
rises and reaches
the
P
P
x
S1
=
P
P
x
S2
+spring force of spring (2),
spool (1) is moved to the right.
Pump circuit
P
P
is then connected to tank circuit
T
through the drill hole.
.
In this way, pump discharge pressure
P
P
is set to
16 bar (16 kg/cm
2
).
P
P
=Pump circuit
P
LS
=LS circuit
T
=Tank circuit
A
=To valves
B
=To pump
LS
valve
10-56
PC20R-8 PC27R-8
RKP00720
1
P
P
B
S
3
S
2
T
T
A
S
1
2
P
LS
Содержание F30791
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Страница 114: ...10 96 PC20R 8 PC27R 8...
Страница 115: ...GRUPPO 20...
Страница 116: ...40 28 PC15R 8...
Страница 131: ...PC27R 8 Standard value Permissible value Max 20 Max 30 2 Max 5 2 Max 5 2 Max 5 FOR THE MACHINE 20 15 PC20R 8 PC27R 8...
Страница 180: ...H 20 64 TESTING AND ADJUSTMENTS PC20R 8 PC27R 8...
Страница 181: ...GRUPPO 30...
Страница 182: ...40 28 PC15R 8...
Страница 262: ...30 80 REMOVAL AND INSTALLATION PC20R 8 PC27R 8...
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Страница 264: ...40 28 PC15R 8...
Страница 279: ...40 15 PC20R 8 PC27R 8 RKP01661 Sezione A A 44 1w4 9 Nm 4 5w0 5 kgm 44 1w4 9 Nm 4 5w0 5 kgm Section A A...
Страница 287: ...40 23 PC20R 8 PC27R 8 PAGE INTENTIONALLY LEFT BLANK...
Страница 298: ...40 34 PC20R 8 PC27R 8...