60 - 5
Section E Hydraulics
9803/6410
Section E
60 - 5
Issue 1
Slew Brake Valve
Operation (JS130) (cont’d)
Slew Brake (50% Application)
Five seconds after the control lever has been returned to
neutral, an electric signal from the controller operates
solenoid valve 7 and spool 1 moves down.
Oil in the pressure reducing valve spring chamber d is
connected to tank passageway T.
Pilot pressure entering port P flows to passageway a and
chamber b and tries to lift the reducing valve spool 2. Oil in
chamber b is throttled into passageway e and spring
chamber d and continues to tank.
Simultaneously, part of the flow from chamber b flows
through passageway c to the solenoid control valve 6,
through port B and to the brake port of the slew motor. Oil at
the spring release pressure of the reducing valve 8 enters
the brake area of the slew motor and 50% brake force is
applied.
JS02110