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| Illustration 1 | g06015139 |
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Hydraulic schematic for SWING RIGHT (1) Passage (2) Line (3) Relief valve (4) Swing parking brake (5) Motor rotary group (6) Swing motor (7) Anti-reaction valve (8) Line (9) Line (10) Return circuit (11) Line (12) Main control valve (13) Stick I control valve (14) Swing control valve (15) Passage (16) Passage (17) Passage (18) Passage (19) Load check valve (20) Passage (21) Parallel feeder passage (22) Swing priority valve (23) Line (24) Line (25) Line (26) Idler pump pressure sensor (27) Pilot control valve (28) Shuttle valve (30) Solenoid valve for the swing parking brake (31) Pilot manifold (32) Idler pump (33) Drive pump (34) Pilot pump (41) Implement pressure switch | |
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| Illustration 2 | g03035757 |
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(12) Main control valve
(14) Swing control valve (22) Swing priority valve | |
The oil delivery for the swing hydraulic circuit is supplied by idler pump (32) only. When either one of the joysticks (swing, stick, boom and/or bucket) is moved from the NEUTRAL position, swing parking brake (4) is released. Motor rotary group (5) starts to rotate. When the joystick for the swing function is moved from the NEUTRAL, swing priority valve (22) is activated. The swing motor is mounted on top of the swing drive. The swing drive is installed on the upper structure. The swing drive reduces the motor speed by two stages. The swing drive rotates 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 solenoid valve for the swing parking brake, refer to Systems Operation, "Pilot Valve (Swing Parking Brake)".
When the joystick is moved to the SWING RIGHT position, pilot oil from pilot control valve (27) flows through line (11) to swing control valve (14) and the pilot oil shifts the swing control valve downward. Oil from idler pump (32) flows through parallel feeder passage (21) to load check valve (19). Then, the oil flows from load check valve (19) through passage (18) to swing control valve (14). The oil flows through the swing control valve through passage (16) to line (8). The oil flows through line (8) to motor rotary group (5). The motor rotary group rotates and the upper structure swings to the right.
Return oil from motor rotary group (5) flows through line (9) through passage (15) to swing control valve (14). The oil flows from the swing control valve through passage (20) to the hydraulic tank.
When the joystick is moved to the SWING LEFT position, pilot oil from pilot control valve (27) flows to swing control valve (14) and the pilot oil shifts the swing control valve upward. Oil from idler pump (32) flows through parallel feeder passage (21) to load check valve (19). Then, the oil flows from load check valve (19) through passage (18) to swing control valve (14). The oil flows through the swing control valve through passage (15) to line (9). The oil flows through line (9) to motor rotary group (5). The motor rotary group rotates and the upper structure swings to the left.
Return oil from motor rotary group (5) flows through line (8) through passage (16) to swing control valve (14). The oil flows from the swing control valve through passage (20) to the hydraulic tank.
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| Illustration 3 | g06009822 |
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Pilot manifold (30) Solenoid valve for the swing parking brake (31) Pilot manifold | |
Pilot oil from pilot pump (34) flows through pilot manifold (31) to solenoid valve (30). Pilot oil also flows through line (25) and into the main control valves pilot logic circuit. While the implement controls and the swing control are in the NEUTRAL position, implement pressure switch (41) is OFF and solenoid valve (30) is not energized. Since the solenoid is not energized, pilot oil does not flow through line (2) and swing parking brake (4) is engaged. If only the travel controls are moved from the NEUTRAL position, the swing parking brake will not be released.
When any joystick is moved from the NEUTRAL position, pilot oil pressure increases and implement pressure switch (41) is ON. Since solenoid valve (30) is energized, pilot oil from pilot pump (34) flows through solenoid valve (30) to line (2). The oil flows through line (2) to swing parking brake (4) and the pilot oil releases the swing parking brake. Since the implement pressure switch is turned ON prior to the opening of the swing control valve, the swing motor only operates after the swing parking brake has been released by the pilot oil from line (2).
When the control valves for the implements or for swing are in the NEUTRAL position, the pilot oil pressure decreases. Since solenoid valve (30) is not energized, the oil in line (2) does not flow to swing parking brake (4). The oil in the swing parking brake flows through passage (1) to motor rotary group (5). The oil flows through the motor rotary group through the case drain line back to the hydraulic tank. Swing parking brake (4) begins to be applied, yet the swing parking brake is not fully applied until swing motor (6) comes to a complete stop.
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| Illustration 4 | g03035846 |
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Swing priority valve (13) Stick I control valve (17) Passage to stick I control valve (21) Parallel feeder passage (36) Pilot pressure (37) Spring (38) Spring (39) Stem (40) Passage | |
When the swing joystick is moved from the NEUTRAL position, pilot oil from pilot control valve (27) flows through line (11) and shifts swing control valve (14). Also, pilot oil flows through line (23) to swing priority valve (22).
When the swing joystick is in the NEUTRAL position, the oil from idler pump (32) flows through parallel feeder passage (21) to swing priority valve (22). The oil flows from the swing priority valve through passage (17) to stick I control valve (13).
When the swing joystick is moved from the NEUTRAL position, pilot oil pressure increases in accordance to the travel of the swing joystick. The pressure oil flows through passage (36) and the oil shifts stem (39) upward against the force of spring (37) and spring (38). The oil from parallel feeder passage (21) is restricted at passage (40) to stick I control valve (13). Most of the oil from idler pump (32) flows through swing control valve (14) to swing motor (6). This action allows the machine to provide the bucket with the optimum lateral force in accordance to the travel distance of the swing joystick.