S
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9803/
3280
Issue
1
Steer Unit Operation
- 4 Wheel Steer Machines
4 Wheel Steer Mode
- Shock Valve
In normal operation oil flow from the pump enters
the steering unit via the right hand port, opening a
spring-loaded non-return valve
43C.
The flow is
directed by the steering unit to achieve the desired
turn (right hand shown).
In t he event of a p ressure shoc k w ave b eing
generated in the system by an outside force, shock
valve
43A
vents this pressure to exhaust preventing
damage to the steering unit.
Non- return valve
J2
is held on its seat by the
generated pressure and non- return valve
43C
closes to prevent the shock wave being fed back to
the pump. Some of the excess flows via non-return
valve
J1
to the opposite side of the power track rod
ram to prevent cavitation occuring.
Component Key:
A
Inner Spool
B
Outer Spool
D
Stator
X
Steer Mode Control Valve
J1
Non-Return Valve
J2
Non-Return Valve
43A
Shock Valve
43C
Non-Return Valve
4 -
10
4 -
10
Cir
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S
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