SHAFT-DRIVE 2551572 - Caterpillar

Swing Priority
The pilot oil pressure from the pilot control valve directly corresponds to the amount of movement or position of the joystick. During a swing operation, pilot oil flows from pilot control valve (23) to swing control valve (18). Supply oil from idler pump (29) enters parallel feeder passage (13). Parallel feeder passage (13) supplies oil to swing priority valve (27), passage (22) and swing priority solenoid (20). Pressure sensor (25) for swing control sends an electrical signal to the machine ECM. The machine ECM sends an electrical signal to swing priority solenoid (20) in order to activate swing priority.When swing priority is activated, the output flow from the idler pump supplies hydraulic oil to the swing hydraulic circuit. Since swing priority increases the swing acceleration, swing priority is useful for loading operations. Swing priority is also useful for leveling operations and trenching operations when higher swing force is required.
Illustration 5 g03206787
(18) Swing control valve
(20) Swing priority solenoid
Illustration 6 g03206837
(A) Swing priority ON
(B) Swing priority OFF
(13) Parallel feeder passage
(19) Stick I control valve
(20) Swing priority solenoid
(27) Swing priority valve
(39) Center bypass passage
(43) Check valve
(45) Passage
(46) Swing priority check valve
Illustration 7 g03207236
SWING RIGHT operation (swing priority OFF)
(4) Swing motor
(13) Parallel feeder passage
(18)