HOUSING ASSEM. 9S9763 - Caterpillar

Illustration 1 g00895061
Hydraulic schematic for SWING RIGHT (1) Swing parking brake (2) Line (parking brake release pressure) (3) Swing parking brake solenoid valve (4) Passage (parking brake release pressure) (5) Swing parking brake (6) Front swing motor (7) Rear swing motor (8) Motor rotary group (9) Motor rotary group (10) Passage (swing pump supply oil) (11) Passage (return oil) (12) Passage (swing pump supply oil) (13) Passage (return oil) (14) Line (swing pump supply oil) (15) Line (return oil) (16) Passage (swing pump supply oil) (17) Passage (return oil) (18) Case drain line (19) Passage (swing pump supply oil) (20) Proportional valve for swing left (21) Swing control valve (22) Back pressure valve (23) Line (pilot oil supply to proportional valve) (24) Proportional valve for swing right (25) Line (parking brake release pressure) (26) Line (return oil) (27) Line (swing pump supply oil) (28) Line (return oil) (29) Main control valve (30) Back pressure valve (31) Pilot manifold (32) Line (pilot oil supply) (33) Line (return pilot oil) (34) Hydraulic tank (35) Pilot pump (36) Swing pumpIntroduction
Swing pump (36) supplies oil to rear swing motor (7) and front swing motor (6). The two swing motors are identical in operation. The swing motors have the following differences in construction :
Only the rear swing motor is equipped with the swing parking brake solenoid valve.
The swing relief valve settings are different for each swing motor.Swing control valve (21) is mounted on the top of the rear swing motor. The swing control valve operates both swing motors. During a swing operation, swing parking brakes (1) and (5) release in order for the swing motors to operate. Each swing motor is mounted to a swing drive. The swing drives are identical in construction and operation. The swing drives reduce the motor speed to the second stage in order to rotate the upper structure.SWING RIGHT Operation
Illustration 2 g00895515
Rear swing drive (3) Swing parking brake solenoid valve (7) Rear swing motor (21) Swing control valve
Illustration 3 g00895517
Front swing drive (6) Front swing motorThe oil delivery from pilot pump (35) flows through line (32), pilot manifold (31) and line (23) to proportional valve (24) for swing right and proportional valve (20) for swing left at swing control valve (21). When the swing joystick is in the NEUTRAL position, full pilot pressure at each end of the spool in swing control valve (21) maintains the spool in the center position. The oil delivery from the pilot pump also flows through line (25) to swing parking brake solenoid valve (3) .When the swing joystick is moved in order to perform a SWING RIGHT operation, the swing joystick sends an electrical signal input to the machine electronic control module.The machine electronic control module sends an electrical signal to swing parking brake solenoid valve (3) at rear swing motor (7). When the swing parking brake solenoid valve is energized, pilot oil in line (25) flows through swing parking brake solenoid valve (3) and passage (4) to the swing parking brake (5). The pilot