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| Illustration 1 | g06603546 |
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Hydraulic schematic for swing right (1) Return port (2) Swing brake solenoid (3) Accumulator (4) Passage (5) Swing control valve (6) Swing left solenoid (7) Parallel feeder passage (8) Main relief valve (9) Slow return check valve (10) Line (11) Passage (12) Pilot pressure reducing valve (13) Center bypass passage (14) Check valve (15) Center bypass passage (16) Parallel feeder passage (17) Main control valve (18) Swing priority valve (19) Swing priority solenoid (20) Hydraulic lock solenoid (21) Swing right solenoid (22) Passage (23) Pressure port (pump 2) (24) Pump 2 pressure sensor (25) Pump 1 pressure sensor (26) Pressure port (pump 1) (27) Swing parking brake (28) Swing motor (29) Swing relief valve (30) Swing relief valve (31) Line (32) Make-up line (33) Line (34) Line (35) Hydraulic tank (36) Pump 1 (37) Pump 2 | |
The oil delivery for the swing hydraulic circuit is supplied by pump 2 (37). When the swing joystick is moved from the NEUTRAL position, swing brake solenoid (2) is activated by the machine ECM. Swing parking brake (27) is then released. Swing motor (28) starts to rotate. 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 swing brake solenoid valve, refer to Systems Operation , "Pilot Valve (Swing Parking Brake)".
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| Illustration 2 | g06197214 |
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Main control valve (2) Swing brake solenoid (5) Swing control valve (6) Swing left solenoid (21) Swing right solenoid | |
Swing control valve (5) consists of a swing right solenoid (6) and swing left solenoid (21) which are controlled by the machine ECM.
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| Illustration 3 | g06607921 |
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Compartment for the swing motor (typical example) (10) Line (17) Main control valve (28) Swing motor (31) Line (32) Make-up line (33) Line (34) Line | |
The oil delivery from pump 2 (37) flows through parallel feeder passage (7) in main control valve (17) to swing control valve (5). The oil delivery from pump 1 (36) flows through center bypass passage (15) in main control valve (17). Illustration1 shows main control valve (17) when only the swing hydraulic circuit is activated.
The oil delivery from pump 2 (37) also flows through parallel feeder passage (7) to pressure reducing valve (12). Pilot oil then flows through check valve (14) to swing brake solenoid (2) and to hydraulic lockout solenoid (20). When the hydraulic lockout lever is in the UNLOCKED position, the machine ECM energizes hydraulic lockout solenoid (20). Pilot oil flows through hydraulic lockout solenoid to swing right solenoid (21) and swing left solenoid (6). During a swing operation the joystick position sensor sends an input signal to the machine ECM. The machine ECM then energizes swing brake solenoid (2). The swing brake solenoid valve shifts. Pilot oil flows through pilot line (10) to swing parking brake (27). The swing parking brake releases in order to enable a swing operation.
When the swing joystick is moved to the SWING RIGHT position, the machine ECM energizes swing right solenoid (21). Pilot oil from pressure reducing valve (12) flows through passage (11), hydraulic lock solenoid (20), swing right solenoid (21), and to swing control valve (5). Pilot oil shifts the spool in swing control valve (5). The machine ECM also energizes swing brake solenoid valve (2). Swing brake solenoid valve (2) shifts. Pilot oil flows through line (10) to swing parking brake (27). Swing parking brake (27) releases in order to enable a swing operation.
The oil delivery from pump 2 (37) flows through parallel feeder passage (7) and through swing control valve (5). The oil then flows through line (34) to swing motor (28). Swing motor (28) rotates and the upper structure swings to the right.
Return oil from swing motor (28) flows through line (33) to main control valve (17). The return oil flows through swing control valve (5), return passage (4), and slow return check valve (9) to hydraulic tank (32).
The SWING LEFT operation is similar to the SWING RIGHT operation.
When the stick and swing are both in being operated, swing priority restricts oil flow to the stick. Since swing priority increases the swing acceleration, swing priority is useful for loading. Swing priority is also useful for leveling and trenching when higher swing force is required.
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| Illustration 4 | g06197650 |
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Main control valve (rear view) (5) Swing control valve (19) Swing priority solenoid | |
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| Illustration 5 | g06241137 |
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Main control valve (front view) (18) Swing priority valve | |
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| Illustration 6 | g06197723 |
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SWING RIGHT operation (swing priority OFF) (5) Swing control valve (7) Parallel feeder passage (11) Passage (12) Pilot pressure reducing valve (17) Main control valve (18) Swing priority valve (19) Swing priority solenoid (20) Hydraulic lock solenoid (21) Swing right solenoid (28) Swing motor (35) Hydraulic tank (36) Pump 1 (37) Pump 2 (39) Passage (40) Stick 1 control valve (41) Stick 2 control valve (42) Passage | |
When the swing joystick is moved slightly from the NEUTRAL position in order to perform a SWING RIGHT operation, reduced oil pressure from pressure reducing valve (12) flows through pilot line (11), through swing right solenoid (21), and to swing control valve (5). The spool in swing control valve (5) shifts a slight amount that corresponds to the amount of movement of the swing joystick.
The oil delivery from pump 2 (37) supplies oil to parallel feeder passage (7) through swing priority valve (18) to stick 1 control valve (40).
Swing priority is deactivated by de-energizing power to swing priority solenoid (19) and allowing spring pressure to shift swing priority valve (18) to the NEUTRAL position.
The swing priority valve does not restrict the parallel feeder passage (7) for stick 1 control valve (40) when the swing lever is in neutral or a slight swing lever command condition.
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| Illustration 7 | g06196592 |
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SWING RIGHT operation (swing priority ON) (5) Swing control valve (7) Parallel feeder passage (11) Passage (12) Pilot pressure reducing valve (17) Main control valve (18) Swing priority valve (19) Swing priority solenoid (20) Hydraulic lock solenoid (21) Swing right solenoid (28) Swing motor (35) Hydraulic tank (36) Pump 1 (37) Pump 2 (39) Passage (40) Stick 1 control valve (41) Stick 2 control valve (42) Passage | |
As the swing joystick is moved to the FULL STROKE position during a SWING RIGHT operation, the pilot oil pressure in passage (11) increases. The spool in swing control valve (5) shifts fully. The machine ECM energizes swing priority solenoid (19) allowing pilot oil to shift swing priority valve (18).
The oil delivery from pump 2 (37) supplies oil to parallel feeder passage (7), through swing priority valve (18) to stick 1 control valve (40). The oil supply to stick 1 control valve (40) is restricted by swing priority valve (18).
Note: Pump 1 (36) supplies oil to stick 2 (41) control valve during a combined swing and stick operation.
Swing priority is activated by energizing power to swing priority solenoid (19) shifting swing priority valve (18). Supplying flow through swing priority solenoid (19) overrides the spring in swing priority valve (18). Most of the oil delivery from pump 2 (37) is dedicated to the swing system and flows through swing control valve (5) to swing motor (28). As a result, swing priority and higher swing force can be achieved with the swing joystick.