1.Unload valve
FUNCTION
1) In the case of fixed pump system, the Unload valve has functions included variable pump and
LS
valve of varia-
ble pump system.
.
When the control valve is at HOLD, pump discharge amount Q is released to the tank circuit.
.
When the control valve is operated, the flow from pump is sent to the actuator circuit in proportion to the opening
areas of valve spool.
.
The
LS
differential pressure
D
P
LS
is become variable according to engine speed.
(Engine speed sensing function).
OPERATION
When control valve is at HOLD
.
At the left end of spool (1), pump pressure
P
P1
is
acting on area
S1
, and at the right end of spool
(1), pump pressure
P
P2
and spring force of spring
(2) is acting on area
S2
, and
LS
pressure
P
LS
is ac-
ting on area
S3
.
.
The reason of difference between pump pressure
P
P1
and
P
P2
comes from pressure loss
P
P
, when
the pump discharge amount passes through the
orifice (3) of spool (1). (
P
P1
=
P
P2
+
D
P
P
).
.
When the control valve is at HOLD,
LS
pressure
P
LS
is not generated, so the pump pressure
P
P1
,
P
P2
, and spring force of spring (2) is acting on spool
(1).
.
As pump discharge pressure
P
P1
rises and reaches
the
P
P2
x
S1
=
P
P1
x
S2
+ spring force of spring (2),
spool (1) is moved to the right. Pump circuit
P
P1
,
P
P2
are then connected to tank circuit
T
through
the drill hole.
.
In this way, the differential pressure (
LS
differential
pressure) between pump discharge pressure
P
P1
and
LS
pressure
P
LS
is set to 19.6
9.8
bar (20
10
kg/cm
2
).
P
P
=Pump circuit
P
LS
=Load Sensing circuit
T-TS
=Tank circuit
A
=To control valve spool
B
=To
LS
valve
10-48
PC12R-8 PC15R-8
To actuator
RKP00381
A
B
1
P
P1
S
3
T
S
S
1
2
P
LS
P
P2
T
3
S
2
Содержание PC12R-8 MISTRAL
Страница 1: ......
Страница 2: ...40 28 PC15R 8 ...
Страница 4: ...00 2 PC12R 8 PC15R 8 ...
Страница 17: ...GROUP 10 ...
Страница 18: ...40 28 PC15R 8 ...
Страница 30: ...10 12 PC12R 8 PC15R 8 PAGE INTENTIONALLY LEFT BLANK ...
Страница 32: ...10 14 PC12R 8 PC15R 8 PAGE INTENTIONALLY LEFT BLANK ...
Страница 34: ...10 16 PC12R 8 PC15R 8 PAGE INTENTIONALLY LEFT BLANK ...
Страница 36: ...10 18 PC12R 8 PC15R 8 PAGE INTENTIONALLY LEFT BLANK ...
Страница 38: ...10 20 PC12R 8 PC15R 8 PAGE INTENTIONALLY LEFT BLANK ...
Страница 40: ...10 22 PC12R 8 PC15R 8 PAGE INTENTIONALLY LEFT BLANK ...
Страница 42: ...10 24 PC12R 8 PC15R 8 PAGE INTENTIONALLY LEFT BLANK ...
Страница 44: ...10 26 PC12R 8 PC15R 8 PAGE INTENTIONALLY LEFT BLANK ...
Страница 79: ...10 61 PC12R 8 PC15R 8 PAGE INTENTIONALLY LEFT BLANK ...
Страница 130: ...10 112 PC12R 8 PC15R 8 PAGE INTENTIONALLY LEFT BLANK ...
Страница 132: ......
Страница 133: ...GROUP 20 ...
Страница 134: ...40 28 PC15R 8 ...
Страница 149: ...PC15R 8 Standard value Permissible value Max 20 Max 30 2 Max 5 2 Max 5 2 Max 5 FOR THE MACHINE 20 15 PC12R 8 PC15R 8 ...
Страница 158: ...20 24 PC12R 8 PC15R 8 PAGE INTENTIONALLY LEFT BLANK ...
Страница 198: ......
Страница 199: ...GROUP 30 ...
Страница 200: ...40 28 PC15R 8 ...
Страница 283: ...GROUP 40 ...
Страница 284: ...40 28 PC15R 8 ...
Страница 295: ...HYDRAULIC PUMP PC12R 8 40 11 PC12R 8 PC15R 8 RKP00910 Z Vista Z 68 6 Nm 7 kgm 48 Nm 4 9 kgm View Z ...
Страница 298: ...40 14 PC12R 8 PC15R 8 RKP00131 Sezione A A 44 1w4 9 Nm 4 5w0 5 kgm 44 1w4 9 Nm 4 5w0 5 kgm Section A A ...
Страница 304: ...40 20 PC12R 8 PC15R 8 RKP00201 Sezione A A 44 1w4 9 Nm 4 5w0 5 kgm 44 1w4 9 Nm 4 5w0 5 kgm Section A A ...
Страница 317: ...40 33 PC12R 8 PC15R 8 PAGE INTENTIONALLY LEFT BLANK ...
Страница 324: ......