Priority Valve Operation 2 - Turning - jcb 214e Service Manual

Priority Valve Operation 2
- Turning
As the steering unit 43 is operated, pressure is
applied to the spring end of the priority valve spool
2B via sensing line LS from the steering unit.
This reduces the pressure differential across the
spool, causing it to move to the right under spring
force. This allows priority valve flow to the steering
unit which directs the flow to the power track rod
rams 40 and 41 untill the required steering lock is
reac hed . When t he st eering lo c k is held t he
pressure signal across the side port LS of the
st eering unit c eases, rest o ring t he p ressure
differential across spool 2B. The spool moves back
to the left, allowing full pump flow to the loader
control valve 3.
Because the pump output is always greater than
the flow required to operate the steering system,
flow to the loader valve is never completely cut off.
Maximum steering system pressure is controlled by
relief valve 43B, located in the steering unit 43.
Component Key:
LS Load Sensing Port
P From pump
T To Loader Valve
2 Priority Valve
2A Spring
2B Spool
2C Drilling
3 Loader Valve
40 Front Power Track Rod Ram
41 Rear Power Track Rod Ram
43 Steer Unit
43B Relief Valve
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