10-80
WB97S-5
STRUCTURE AND FUNCTION
PPC VALVES
2. During fine control (NEUTRAL
o
Actuator)
When the disk (5) starts pushing down on piston (4)
and piston (10), the retainer (9) moves as a result.
This movement will compress the spring (2) which
will in turn act on the spool (1) and push it
downwards.
As a result of this action, the calibrated hole
f
will be
isolated from the drain chamber
D
and at almost at
the same time it will be put in connection with the
PP
chamber, which is directly connected to the
servocontrols circuit.
Pressure in the servocontrols circuit will flow
through the calibrated hole
f
and into the circuit
thereby increasing the pressure in duct
P1-B
.
When pressure
P1
increases, spool (1) is pushed
upwards, and calibrated hole
f
is connected back to
discharge chamber
D
thereby compressing the
spring (2).
The floating of the spool (1) will continue until
calibrated hole
f
is halfway between discharge
chamber
D
and pressure chamber
PP
, in other
words until the pressure in duct
P1
– the pressure
acting on the section of stem (1) – offsets the force
applied by the spring (2).
The spring (2) is compressed proportionally to the
movement of the disk (5) and therefore, pressure at
P1
increases in proportion to the travel of the disk
(5).
The equilibrium position is then kept until the
position of piston (4) is changed, i.e.:
a) as long as pressures at ports
B
and
P1
are
perfectly balanced;
b) until pressure in section
B-P1
– i.e. the
pressure acting on stem (1) – is enough to
counteract the force of the spring (2).
This ensures proportionality between control lever
position,
B-P1
circuit pressure, and main control
valve stem displacement.
RKZ09000
T
P
f
D
P1
P2
A
B
PP
9
10
4
5
1
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 ...