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9803/
3280
Issue
1
Steer Unit Operation
- 4 Wheel Steer Machines
4 Wheel Steer Mode
- Left Turn
The illustration shows the flow through the steering
unit in a left hand t urn c ond it ion. Turning t he
steering wheel rotates the inner spool
A
a few
degrees relative to the outer spool
B
, and sends a
pressure signal to the relief valve
43B
and through
the
LS
port back to the priority valve.
The relative movement between
A
and
B
directs
pressure oil through 6 of the 12 holes in the bottom
of sleeve
B
. The metering unit is linked to the
spools by a cross pin. As the steering is operated
the oil is diverted by inner spool
A
into the stator
D
.
The rotor lobes pump the oil out to one side of the
rear power track rod ram
41
turning the rear wheels
to the right. At the same time pressurised oil from
the other side of the power track rod ram
41
is fed
to the front power track rod ram
40
, hence turning
the front wheels the required degree of left turn.
Component Key:
A
Inner Spool
B
Outer Spool
D
Stator
LS
Load Sensing Port
X
Steer Mode Control Valve
40
Front Power Track Rod Ram
41
Rear Power Track Rod Ram
43B
Relief Valve
4 -
5
4 -
5
Cir
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