HYDRAULICS – CX210/CX240
6 - 22
CX EXCAVATORS
SWING
Swing Priority
1) A priority circuit assures swing operation when swing and arm is operated at the same
time.
When operating the swing and arm simultaneously as in bank shaving or bank cutting
operation, a priority circuit in the control valve achieves swing priority.
Oil flow from pump1 (front pump) enters the P1 port of the control valve and flow from pump2
(rear pump) enters the P2 port. When swing right or left is activated pilot pressure is sent
from the swing shuttle valve to the swing priority valve in the main control valve. This allows
the priority valve to remain in the restricted (orifice) position. Which prioritizes pump1 oil for
swing over the arm circuit.
During boom up operation pilot pressure is sent to the boom2 spool, which shuts off the open
center passage to the arm1 spool. Pilot pressure is routed from the boom up pilot control
circuit to the other side of the swing priority valve. This shifts the priority valve to the
unrestricted position, which assures pump1 oil flow for arm circuit operation.
When swing and arm or boom up is operated at the same time, the swing priority valve
remains in the restricted (orifice) position. This is due to the valve being spring biased to the
restricted position.
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