MOTOR AS 1648243 - Caterpillar

Illustration 1 g00852732
Pressure circuit for swing system (1) Passage (supply oil or return oil) (2) Relief valve (3) Passage (4) Check valve (5) Front swing motor (6) Motor rotary group (7) Passage (supply oil or return oil) (8) Relief valve (9) Makeup port (10) Check valve (11) Return line (12) Port (supply oil or return oil) (13) Port (supply oil or return oil)
Illustration 2 g00852948
Front swing motor (2) Relief valve (8) Relief valve (9) Makeup port
Illustration 3 g00852735
Relief valve (3) Passage (7) Passage (14) Orifice (15) Spring (16) Stem (17) Piston chamber (18) Piston (19) Passage (20) Adjustment plug (21) Passage (22) Orifice (23) Piston chamber (24) PassageThis machine is equipped with two swing motors and two swing drives. Line relief valves are located on both the rear swing motor and the front swing motor. The operation of the line relief valves in the front swing motor is identical to the operation of the line relief valves of the rear swing motor.Relief valves (2) and (8) are located in top of front swing motor (5) . These relief valves limit the pressure in the front and rear swing circuits to the relief setting. This provides a cushion effect at a start or stop of the swing operation.When the swing joystick is returned to the NEUTRAL position during the swing right operation, the inlet port and the outlet port of the swing control valve are closed. Oil flow is now blocked at port (12) and port (13) of the swing motor.The mass (weight and size) of the upper structure causes the upper structure to attempt to continue to rotate after the swing joystick is returned to the NEUTRAL position. The motor rotary group is also attempting to continue to rotate. The motor rotary group attempts to draw oil through port (12) and attempts to displace the oil through port (13) .The oil supply to the motor rotary group is insufficient. A vacuum condition occurs in passage (1) . Return oil is supplied to the motor rotary group as makeup oil in order to prevent the vacuum condition. For more information concerning the makeup operation, refer to Systems Operation, "Oil Makeup (Swing System)". Since the flow of return oil from the motor rotary group through port (13) is blocked at the swing control valve, the pressure of the blocked oil in passage (7) increases. The increased oil pressure in passage (7) acts on swing relief valve (8) . The increased pressure oil forces stem (16) of relief valve (8) to the right (open position) against the force of spring (15) . When stem (16) shifts, oil flows through passage (7) , check valve (4) and passage (1) to the motor rotary group. The shock load is absorbed at the stop of a swing movement.At swing relief valve (8) , the increased oil pressure in passage (7) flows through orifice (14) in stem (16) and passage (24) to piston chamber (23) . The force of spring (15) is less than the relief valve pressure