7 - 3
Loader Valve - Variable Flow
Priority Inlet Section Operation
Service Selected (no steering demand)
If the steering is not selected, there will be no pressure
demand signal in chamber
C
. Pump pressure is ‘dead
ended’ at the steer unit, this pressure is felt in chamber
F
via
priority port
PR
and drilling
G
. The pressure is sufficient to
force spool
E
down against the force of spring
D
. The
position of the spool now allows oil from the pump inlet port
P
to flow into passage
H
and on to the selected service via
the valve block service ports.
Component Key:
P
Pump Inlet
T
Tank
LS
Load sense port (to pump)
PRLS
Priority Load Sense Port (from steer unit)
PR
Priority Work Port (to steer unit)
Section E
9803/3280
Section E
7 - 3
Issue 1
Circuit Descriptions
LS
T
P
PRLS
PR
G
F
D
C
E
J
4
H
EXHAUST
PUMP
LOAD SENSE
PR
PR
P
PRLS
LS
T
A273970
A273980