10 - 5
Operation (cont’d)
Pilot Pump (Pp)
As the pump gears revolve, oil from the inlet port
Y
is
trapped between the gears and the housing and carried to
the outlet port
Z
.
Regulator
The function of each regulator is to maximise the efficiency
of its associated pump circuit by making it respond to
system demand i.e. adjusting the output flow to satisfy the
changing requirements of the machine services. This is
achieved by varying the angle of the pump swash plate.
The following description refers to pump
P1
. The circuit for
pump
P2
functions in exactly the same way.
Flow Control
Pump
P1
pressure is routed to piston
32
, regulator piston
24
(small diameter chamber ‘a’) and spool
40
. Pump
P2
pressure is also routed to piston
32
. Pilot pump
Pp
pressure
and horsepower control signal
K
(which is derived from
Pp
pressure and related to the operating mode selected)
produce control pressure
PC
which is equal to 5% of total
pump pressure (
P1
+
P2
).
Pressure
PC
, routed to piston
38
, increases with pump
pressure. The piston moves spool
40
to the left to direct
pump
P1
pressure to the large diameter chamber ‘A’ of
regulator piston
24
. This causes piston
24
to move to the
right to reduce the swash plate angle and decrease oil flow.
Bridging piece
29
, connected to piston
24
, compresses
springs
43
/
44
to act against
PC
pressure through piston
38
.
When
PC
pressure and the pressure of springs
43
/
44
are
equal the regulator piston stops moving.
Pressure
PC
decreases as pump pressure falls and springs
43
/
44
cause spool
40
to move to the right, connecting
chamber ‘A’ of regulator piston
24
to the case drain.
P1
pressure at chamber ‘a’ causes regulator piston
24
to move
to the left to increase the swash plate angle and increase oil
flow. When pressure
PC
and the pressure of springs
43
/
44
are equal the regulator piston stops moving.
Negative Control
When the pump output is not being used (or is at a very low
rate) pressure signal
A
, derived from the main control valve,
acts on piston
38
in the same way as pressure signal
PC
,
described under
Flow Control
, to minimise oil flow.
Horsepower Control
The operation of the pump is based on the principle that at a
given horsepower setting:
“pressure x output flow rate = constant”
The setting can be varied using the signal
K
as described
under
Flow Control
. Signal
K
is controlled by the Solenoid
Proportional Pressure Control valve (SPPC), the output of
which is determined by electric signals according to the
working mode selected.
Maximum Flow Cut
When the maximum flow cut signal
B
is present, it acts on
piston
54
to operate spool
40
via piston
38
, as described
under
Flow Control
. Due to the diameter of piston
54
being
smaller than that of piston
38
, maximum flow is 65% of that
obtainable under normal flow control conditions.
Section E
Hydraulics
9803/6410
Section E
10 - 5
Issue 1
Hydraulic Pump/Regulator
Содержание JS130
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Страница 119: ...3 1 Section C Electrics 9803 6410 Section C 3 1 Issue 1 Layout Operator s Cab...
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Страница 159: ...5 20 Section C Electrics 9803 6410 Section C 5 20 Issue 1 Pump Control Swing brake Swing lock continued Flow Chart...
Страница 160: ...5 21 Section C Electrics 9803 6410 Section C 5 21 Issue 1 Pump Control Lever Lock Circuit Diagram Time Chart...
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Страница 210: ...3 4 Section E Hydraulics 9803 6410 Section E 3 4 Issue 2 Schematics Shuttle Block...
Страница 211: ...Section E Section E Hydraulics 9803 6410 Issue 2 3 5 3 5 Schematics Pilot Control Line Hose Connection Diagram JS03540...
Страница 212: ...Section E Section E Hydraulics 9803 6410 Issue 1 3 6 3 6 Schematics Pilot Control Line Hose Connection Diagram JS03540...
Страница 234: ...14 1 Section E Hydraulics 9803 6410 Section E 14 1 Issue 1 JS00010 Hydraulic Pump Regulator Dismantling and Assembly...
Страница 278: ...32 2 Hydraulic Circuit Diagram Section E Hydraulics 9803 6410 Section E 32 2 Issue 1 Control Valve JS01700...
Страница 279: ...33 1 Neutral Circuit Section E Hydraulics 9803 6410 Section E 33 1 Issue 1 Control Valve JS01610...
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Страница 293: ...Hydraulics 9803 6410 Issue 1 34 3 34 3 Section E Section E Control Valve JS01820 Dismantling and Assembly cont d...
Страница 532: ...Contents Page No Technical Data 1 1 i Engine 9803 6410 i Issue 1 Section K Section K...