10-81
WB97S-5
STRUCTURE AND FUNCTION
PPC VALVES
3. During fine control
(Actuator
o
NEUTRAL)
When the disk (5) is released and moved to neutral
position, the piston (4) is pushed upwards by the
spring (3) acting on the retainer (9), and spool (1) is
thrusted upwards both by the force of spring (2) and
by the force that the pressure in section
B-P1
applies against the stem.
This movement moves the calibrated hole
f
of spool
(1) into the discharge chamber
D
, thereby allowing
pressure in section
B-P1
to be released.
If pressure
P1
drops too quickly, spool (1) is pushed
downwards by spring (2) and the calibrated hole
f
becomes cut off from the discharge chamber
D
; at
almost the same time, the calibrated hole
f
is put in
connection with pressure chamber
PP
and starts
supplying pressure to section
P1
until the pressure
corresponding to the control lever position is
balanced.
When the spool of the control valve returns, oil flows
back into chamber
D
, through calibrated hole
f'
, and
into chamber
B
of the control valve spool opposite
the operating one.
Oil flows through duct
P2
and into chamber
B
to
ensure it is filled properly.
4. During fine control
(NEUTRAL
o
Full stroke)
When the disk (5) pushes down on the piston (4),
and the retainer (9) pushes down on the spool (1),
calibrated hole
f
is put in direct connection with
chamber
PP
, which is in turn connected to a
constantly pressurised servocontrols circuit.
Oil is then allowed to flow directly into section
B-P1
thereby pushing the stem of the main control valve
to the end of its travel. This causes the main control
valve to send the oil contained in chamber
AB
towards input
P2
, through calibrated hole
f'
and into
relief chamber
D
.
RKZ09010
A
B
1
T
P
D
P1
P2
4
5
9
2
PP
f
3
p
Control
valve
RKZ09020
A
B
T
P
D
P1
P2
9
PP
f
p
4
5
Control
valve
Summary of Contents for WB97S-5
Page 1: ...WEBM007500 WB97S 5 BACKHOE LOADER SERIAL NUMBER F00003 and up WB97S 5 SHOP MANUAL ...
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Page 161: ...TESTING AND ADJUSTMENTS WB97S 5 20 17 NORMAL OR STANDARD TECHNICAL DATA Fig S RKZ10830 ...
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Page 581: ...40 15 WB97S 5 STANDARD MAINTENANCE CONTROL VALVE RKZ09071 C C B B A A AE AE X View X ...
Page 589: ...40 23 WB97S 5 STANDARD MAINTENANCE CONTROL VALVE ViewX RKZ09591 C C B B A A AE AE ...
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Page 611: ...90 1 WB97S 5 90 OTHER ELECTRICAL DIAGRAM STANDARD VERSION 3 ...
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Page 616: ... 2006 KOMATSU UTILITY EUROPE S p A All Rights Reserved Printed in Europe 06 2006 ...