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| Illustration 1 | g06305259 |
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Hydraulic schematic for a constant SWING RIGHT (1) Swing motor (front) (2) Motor rotary group (3) Swing brake solenoid (4) Swing motor (rear) (5) Motor rotary group (6) Line (pilot) (7) Line (8) Line (9) Pilot manifold (10) Passage (11) Swing left PHMV (12) Flow combiner spool (13) Swing control valve (14) Rear pump bypass PHMV (15) Swing pressure sensor (16) Flow combiner PHMV (17) Swing right PHMV (18) Front pump bypass PHMV (19) Main Control Valve Center Manifold (20) Makeup line (21) Pilot pump (22) Front pump (23) Rear pump | |
The oil delivery for the swing hydraulic circuit is supplied by rear pump (23) only. When the joystick is moved from the NEUTRAL position, swing brake solenoid (3) is released. Motor rotary group (2) and (5) start to rotate. The swing motors are mounted on top of the swing drives. The swing drives are installed on the upper structure. The swing drives reduce the motor speed by two stages. The swing drives rotate the upper structure.
Reference: For more information concerning the operation of the swing motor, refer to Systems Operation, "Swing Motor".
Reference: For more information concerning the operation of the swing drive, refer to Systems Operation, "Swing Drive".
Reference: For more information concerning the operation of the swing parking brake and the swing brake solenoid valve, refer to Systems Operation, "Pilot Valve (Swing Parking Brake)".
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| Illustration 2 | g03481480 |
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Main control valve (11) Swing left PHMV (17) Swing right PHMV | |
Swing control consists of two electronically controlled Proportional Hydraulic Modulation Valves (PHMV) which are controlled by the ECM.
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| Illustration 3 | g03481482 |
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Compartment for the swing motor (1) Swing motor (front) (4) Swing motor (rear) (7) Line (8) Line (20) Makeup line | |
The oil delivery from rear pump (22) flows to rear pump bypass PHMV (14) inside of main control valve center manifold (19). The oil delivery from front pump (22) flows to front pump bypass PHMV (18) inside of main control valve center manifold (19). When the swing joystick is in the NEUTRAL position, rear pump oil flows through bypass spool and returns to the hydraulic tank. Illustration 1 shows the main control valve when only the swing hydraulic circuit is activated.
When the hydraulic lockout lever is in the UNLOCKED position, the oil delivery from pilot pump (21) flows to pilot oil manifold (9) and swing brake solenoid (3). During a machine operation the joystick position sensor sends an input signal to the machine ECM. The machine ECM then energizes swing brake solenoid (3). The swing brake solenoid valve shifts. Pilot oil flows through the pilot line to swing parking brake. The swing parking brake releases in order to enable a swing operation.
When the swing joystick is moved to the SWING RIGHT position, rear pump bypass PHMV (14) begins to modulate the rear pump bypass PHMV (14) and swing right PHMV (17) according to the joystick position. Front pump oil then flows through the main control valve center manifold (19) suppling the swing motors.
The two swing motors are identical in operation. The swing motors have the following differences in construction:
- Only the front swing motor is equipped with anti-reaction valve
- Only the rear swing motor is equipped with solenoid valve for the swing parking brake
The SWING LEFT operation is similar to the SWING RIGHT operation.