CHARGER 5450902 - 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 g02255234
(18) Swing control valve (20) Swing priority solenoid
Illustration 6 g02311473
(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 g02258134
SWING RIGHT operation (swing priority OFF) (4) Swing motor (13) Parallel feeder passage (18) Swing control valve (19) Stick I control valve (20) Swing priority solenoid (21) Passage (22) Passage (23) Pilot control valve (swing and stick) (24) Pilot line (27) Swing priority valve (29) Idler pump (38) Passage (43) Check valve (45) PassageWhen the swing joystick is moved slightly from the NEUTRAL position in order to perform a SWING RIGHT operation, reduced pilot oil pressure from pilot control valve (23) flows through pilot line (24). The spool in swing control valve (18) shifts a slight amount that corresponds to the amount of movement of the swing joystick. The machine ECM sends an electrical signal to swing priority solenoid (20) in order to energize the solenoid. The swing priority solenoid shifts to the right.The oil delivery from idler pump (29) supplies oil to parallel feeder passage (13). Parallel feeder passage (13) supplies oil to swing priority solenoid (20) through passage (38). Supply oil in passage (22) is blocked by swing priority solenoid (20) to the spring side of swing priority valve (27). Oil from swing priority valve (27) is bled to the return side through an orifice that is located in swing priority solenoid (20). Oil pressure from parallel feeder passage (13) can now flow through swing priority valve (27). Oil from parallel feeder passage (13) supplies oil to stick I control valve (19) .Swing priority is now deactivated by supplying power to swing priority solenoid (20). Supplying power to swing priority solenoid (20) overrides the spring in the solenoid. Oil delivery from the idler pump is supplied to swing control valve (18) and stick I control valve (19).
Illustration 8 g02258614
Stick I control valve and bucket control valve (swing priority OFF) (13) Parallel feeder passage (19) Stick I control valve (20) Swing