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| Illustration 1 | g00933655 |
The swing motor is mounted on the swing drive.
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| Illustration 2 | g00921028 |
Swing motor (1) Relief valve (2) Relief valve (3) Motor head (4) Port (pilot system oil) (5) Separator plate (6) Friction plate (7) Plate (8) Body (9) Drive shaft (10) Check valve (11) Makeup port (12) Drain port (13) Passage (supply oil or return oil) (14) Check valve (15) Passage (supply oil or return oil) (16) Port (supply oil or return oil) (17) Port (supply oil or return oil) (18) Passage (supply oil or return oil) (19) Valve plate (20) Passage (supply oil or return oil) (21) Brake spring (22) Brake piston (23) Piston (24) Cylinder barrel (25) Retainer plate (26) Shoe (27) Anti-reaction valves | |
The swing motor may be divided into the following four groups:
- The rotary group consists of the following components: cylinder barrel (24), pistons (23), shoes (26), retainer plate (25) and drive shaft (9) .
- The parking brake consists of the following components: brake spring (21), brake piston (22), separator plate (5) and friction plate (6) .
- The relief valves and the makeup valves consists of the following components: relief valve (1), relief valve (2), check valve (10) and check valve (14) .
- Anti-reaction valves (27)
Oil from the main pumps is delivered to port (16) or port (17). During a SWING RIGHT operation, the oil delivery enters the motor head at port (17) and flows through passage (18). The oil then flows through passage (13) in valve plate (19) and passes through passage (20) in cylinder barrel (24). This oil pressurizes piston (23) in motor head (3).
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| Illustration 3 | g00921072 |
Motor Passages (A) Bottom center position. (B) Inlet side (high pressure). (C) Top center position. (D) Outlet side (low pressure). (13) Passage (valve plate). (15) Return passage. (16) Port. (17) Port. (18) Supply passage. (20) Passage (cylinder barrel). (28) Passage (valve plate). (29) Direction of motor rotation (counterclockwise rotation). | |
Shoe (26) is pressed against the upper surface of plate (7) by the force of piston (23). The shoe and the piston slide along the slope of plate (7) in a counterclockwise direction. This sliding force causes cylinder barrel (24) to rotate in a counterclockwise direction (29). As each piston reaches the bottom center position (A) oil flows through passages (28). This oil then flows through passage (15) to port (16). As cylinder barrel (24) continues to rotate counterclockwise, the pistons and the shoes continue to move up the inclined surface of plate (7). Since cylinder barrel (24) is splined to drive shaft (9), the drive shaft rotates in the same direction as the cylinder barrel.
For a SWING LEFT operation, oil from the main pumps is delivered to port (16). The supply ports and the return ports are reversed. Cylinder barrel (24) turns clockwise.
The case drain oil from the swing motor returns through drain port (12) through an oil filter to the hydraulic tank.
Relief Valve
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| Illustration 4 | g01174546 |
Pressure circuit for SWING RIGHT operation (partial schematic for felling head system) (1) Return line (2) Motor rotary group (3) Makeup line (4) Passage (supply oil) (5) Line relief valve (6) Line relief valve (7) Swing motor (8) Check valve (9) Check valve (10) Back pressure valve (11) Swing control valve (12) Port (supply and return oil) (13) Port (supply and return oil) (14) Pump oil (15) Left pump (16) Right pump (17) Saw pump | |
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| Illustration 5 | g00925121 |
Swing relief valve (1) Return passage (4) Passage (18) Orifice (19) Spring (20) Stem (21) Piston chamber (22) Passage (23) Piston (24) Passage (25) Retainer (26) Piston chamber (27) Orifice (28) Passage (29) Adjustment plug | |
Relief valves (5) and (6) are located in the motor head of swing motor (7). These relief valves limit the pressure in the left and right swing circuits. This provides a cushion effect at a start or stop of the swing operation.
When the left joystick is returned to the NEUTRAL position during the swing right operation, swing control valve (11) shifts to the NEUTRAL position. Since swing control valve (11) is in the NEUTRAL position, the oil delivery through port (13) to the motor rotary group (2) is now blocked at swing control valve (11). The return oil from motor rotary group (2) through port (12) is also blocked at swing control valve (11) .
The mass (weight and size) of the upper structure causes the upper structure to attempt to continue to rotate after the left 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 (13) and attempts to displace the oil through port (12) .
The oil supply to motor rotary group (2) is insufficient. A vacuum condition occurs in passage (4). Return oil from saw pump (17) is supplied to motor rotary group (2) as makeup oil in order to prevent the vacuum condition. For more information concerning the makeup operation, refer to the section "Makeup Oil".
Since the return oil flow from the motor rotary group is blocked at swing control valve (11), the pressure of the blocked oil in passage (1) increases. The increased oil pressure in passage (1) acts on swing relief valve (6). The increased pressure oil forces stem (20) of relief valve (6) to the right (open position) against the force of spring (19). When stem (20) shifts, oil flows through passage (1), check valve (9) and passage (4) to motor rotary group (2). The shock load is absorbed at the stop of a swing movement.
At the start of a swing operation, relief valve (5) is closed. The oil in passage (4) flows through orifice (18) in stem (20) and passage (24) to piston chamber (26). The force of spring (19) is less than the relief valve pressure setting. This causes stem (20) to move to the right (open position) before the oil pressure in passage (4) reaches the relief valve pressure setting. At the same time, the pressure oil in piston chamber (26) flows through passages (22) and (28). Piston (23) moves to the left against the force of spring (19). The relief setting of the swing relief valve is at maximum pressure.
After stem (20) begins to open and before piston (23) completes the movement to the left, the pressure in the swing hydraulic circuit increases gradually. The pressure in the swing hydraulic circuit does not reach a peak pressure. This is called a two-stage relief operation. The two-stage relief operation absorbs the shock load at the start or stop of a swing operation.
After the start of a swing right operation, the oil delivery from left pump (15) and right pump (16) flows through port (13) and passage (4) to motor rotary group (2). The mass (weight and size) of the upper structure causes an increase of oil pressure in passage (4). Stem (20) of swing relief valve (5) opens slightly. A portion of the high pressure oil in passage (4) flows through makeup line (3) to the hydraulic tank. This gives a smoother acceleration at the start of a swing operation.
Makeup Oil
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| Illustration 6 | g01174552 |
Pressure circuit SWING RIGHT (partial schematic harvester head) (1) Supply passage (2) Motor rotary group (3) Makeup line (4) Return passage (5) Relief valve (6) Relief valve (7) Swing motor (8) Passage (9) Passage (10) Check valve (11) Check valve (12) Check valve (13) Port (14) Port (15) Implement control valve (16) Relief valve (17) Pilot reducing valve (18) Swing control valve (19) Left pump (20) Right pump | |
Note: The makeup oil for the swing motor is supplied by the saw section on the felling head arrangement.
Reference: For more information about the makeup operation, refer to Schematic, RENR6295.
When the left joystick is moved to the NEUTRAL position during the swing right operation, the swing control valve shifts to the NEUTRAL position. The upper structure will attempt to continue to rotate after the left joystick is returned to the NEUTRAL position. As a result, a vacuum condition occurs at passage (1). In order to prevent this vacuum condition, makeup oil is delivered from the inlet of main control valve (15) to swing motor (7) .
When all of the control valves for implements and swing are in the NEUTRAL position, the oil delivery from left pump (19) and right pump (20) flows through implement control valve (15). Check valve (12) is located between makeup line (3) and pilot reducing valve (17). Check valve (12) eliminates the vacuum condition in swing motor (7) due to internal leakage. If a vacuum condition occurs at swing motor (7) during the stop of a swing operation, check valve (12) opens allowing oil from pilot reducing valve (17) to flow through makeup line (3). The oil flows through check valve (10) to motor rotary group (2) as makeup oil.
If the left joystick is moved suddenly toward the NEUTRAL position from the FULL STROKE position, swing control valve (18) partially closes. Until swing control valve (18) reaches the NEUTRAL position, the return oil from swing motor (7) continues to flow through passage (1) and port (13) to the return line. The return oil pressure in passage (1) increases but the return oil pressure in passage (1) remains lower than the pressure setting of swing relief valve (6). Swing relief valve (6) remains in the CLOSED position.
A vacuum condition occurs at port (14) and passage (4) due to the insufficient oil delivery from right pump (19) or due to the tendency of motor rotary group (2) to continue to rotate. Since relief valve (6) remains in the CLOSED position, makeup oil does not flow through relief valve (5), passage (9) and check valve (11) to passage (4) to motor rotary group (2) .
Makeup oil is supplied to motor rotary group (2) from makeup line (3). Makeup oil flows through check valve (12), makeup line (3), check valve (11) and passage (4) to motor rotary group (2). The vacuum condition in passage (4) is eliminated by the makeup oil from pilot reducing valve (17) .
During a left swing operation, the return ports and the supply ports of the swing motor are reversed. Makeup oil flows through check valve (12) if a vacuum condition occurs in passage (1) during a swing left operation.
Anti-Reaction Valves
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| Illustration 7 | g00933648 |
Swing motor (1) Block (2) Swing motor (3) Anti-reaction valve (left swing) (4) Anti-reaction valve (right swing) | |
At the stop of a swing operation, it is difficult to smoothly stop the upper structure and implements at the desired position. This is due to the mass (weight and size) of the upper structure. The outlet port of the swing motor is blocked. This causes an oscillation or a rocking motion in the swing motor. Anti-reaction valves (3) and (4) provide a more exact swing movement. The anti-reaction valves also prevent shock load at the stop of a swing operation. Anti-reaction valves (3) and (4) are located in block (1). Block (1) is mounted on swing motor (2).
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| Illustration 8 | g00925193 |
Anti-reaction valve (neutral position) (1) Block (3) Anti-reaction valve (4) Anti-reaction valve (5) Motor rotary group (6) Passage (7) Port (8) Passage (9) Passage (10) Port (11) Port (12) Passage (13) Spring (14) Valve seat (15) Passage (16) Plunger (17) Passage (18) Spring (19) Piston chamber (20) Passage (21) Spring chamber (22) Spring (23) Valve seat (24) Plunger (25) Spring (26) Piston (31) Passage (36) Swing control valve | |
During a swing operation of the upper structure, the oil delivery from the main pumps flows through passage (8) or port (10) in block (1) to motor rotary group (5). When the left joystick is in the NEUTRAL position, the swing control valve is in the NEUTRAL position. The oil delivery from the right pump is blocked at the swing control valve. No oil delivery flows to the motor rotary group. The return oil from the swing motor is also blocked at the swing control valve.
Plunger (24) in anti-reaction valve (3) shifts downward by the force of spring (25) until the plunger is stopped by piston (26). Valve seat (23) shifts downward by the force of spring (22) until the valve seat comes in contact with plunger (24). Plunger (16) and valve seat (14) in anti-reaction valve (4) are shifted downward in the same manner as anti-reaction valve (3).
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| Illustration 9 | g00951986 |
Anti-reaction valve (swing operation) (1) Block (3) Anti-reaction valve (4) Anti-reaction valve (5) Motor rotary group (6) Passage (7) Port (8) Passage (9) Passage (10) Port (11) Port (12) Passage (13) Spring (14) Valve seat (15) Passage (16) Plunger (17) Passage (18) Spring (19) Piston chamber (20) Passage (21) Spring chamber (22) Spring (23) Valve seat (24) Plunger (25) Spring (26) Piston (31) Passage (34) Spring chamber | |
When the left joystick is moved for a swing operation, the swing control valve shifts. The oil delivery from the main pumps flows through the swing control valve and port (11) in block (1). The oil delivery then flows through port (10), passage (12) and motor rotary group (5). Return oil from the motor rotary group flows through passage (6), passage (8), port (7) and the swing control valve to the hydraulic tank. The motor rotary group rotates.
A portion of the pressure oil from the right pump at port (11) also flows to anti-reaction valves (3) and (4) .
At anti-reaction valve (3), pressure oil from the right pump and the force of spring (22) shifts valve seat (23) upward against plunger (24). Plunger (24) shifts upward against piston (26) .
Pressure oil from the main pumps also flows through passage (9). The pressure oil enters spring chamber (34) of anti-reaction valve (4). Plunger (16) shifts upward against the force of spring (18). Valve seat (14) is moved upward against the force of spring (13) by plunger (16).
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| Illustration 10 | g00698949 |
Anti-reaction valve (swing stop) (3) Anti-reaction valve (4) Anti-reaction valve (5) Motor rotary group (7) Port (8) Passage (9) Passage (10) Port (11) Port (13) Spring (14) Valve seat (15) Passage (16) Plunger (17) Passage (18) Spring (19) Piston chamber (20) Passage (21) Spring chamber (22) Spring (23) Valve seat (24) Plunger (25) Spring (27) Orifice (26) Piston (28) Valve chamber (29) Passage (30) Ball (31) Passage (32) Orifice (33) Ball (35) Valve chamber | |
When the left joystick is returned to the NEUTRAL position, the oil delivery from the main pumps to motor rotary group (5) is blocked at the swing control valve. The motor rotary group continues to rotate due to the mass (weight and size) of the upper structure. Since the return oil flow from the motor rotary group is also blocked at the swing control valve, the oil pressure in passage (8) increases. The oil pressure in port (10) decreases. The increased oil pressure in passage (8) then enters anti-reaction valve (4). The oil flows through passage (15) and passage (17). The oil then enters piston chamber (19). The oil pressure in piston chamber (19) forces plunger (16) upward against the force of spring (18). Valve seat (14) shifts upward against the force of spring (13) .
A portion of the increased oil pressure in passage (8) flows through passage (31) and passage (20). The oil then enters spring chamber (21) in anti-reaction valve (3). The oil pressure in spring chamber (21) forces plunger (24) and valve seat (23) upward against the force of springs (22) and (25) .
As the motor rotary group of the swing motor continues to stop, the oil pressure in passage (8) gradually decreases. The oil pressure in piston chamber (19) decreases. The force of spring (18) causes plunger (16) to shift downward at a rapid rate. Valve seat (14) shifts downward by the force of spring (13). Since orifice (27) restricts the flow of oil from valve chamber (28), valve seat (14) moves in a downward direction more slowly than plunger (16) .
The contact between plunger (16) and valve seat (14) is no longer maintained. The oil pressure in passage (15) forces ball (30) against the top end of plunger (16). The oil in passage (8) now flows through passages (29) and (9) to port (10) .
During the separation of plunger (16) and valve seat (14) in anti-reaction valve (4), anti-reaction valve (3) activates also. In anti-reaction valve (3), the pressure of the oil that flows from passage (8) to spring chamber (21) decreases. The force of spring (25) causes plunger (24) to shift downward. The force of spring (22) causes valve seat (23) to shift downward. Since orifice (32) restricts the flow of oil from valve chamber (35), valve seat (23) shifts more slowly than plunger (24). The contact between plunger (24) and valve seat (23) is no longer maintained. The oil pressure in passage (20) forces ball (33) against plunger (24). Now, the oil flows from passage (8) through passage (31) to port (10) .
Since passage (8) and port (10) are connected by activation of the anti-reaction valves, the swing movement of the upper structure stops with a minimal shock load at a desired position. A more exact swing movement is possible. A slight shock load may occur due to the gear backlash of the swing drive.
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| Illustration 11 | g00698994 |
Anti-reaction valve (reverse rotation) (3) Anti-reaction valve (4) Anti-reaction valve (5) Motor rotary group (7) Port (8) Passage (9) Passage (10) Port (11) Port (13) Spring (14) Valve seat (15) Passage (16) Plunger (17) Passage (18) Spring (19) Piston chamber (20) Passage (21) Spring chamber (22) Spring (23) Valve seat (24) Plunger (25) Spring (27) Orifice (26) Piston (28) Valve chamber (29) Passage (30) Ball (31) Passage (32) Orifice (33) Ball (35) Valve chamber | |
When motor rotary group (5) is slightly rotated in the reverse direction due to the gear backlash, oil pressure in port (10) increases and oil pressure in passage (8) decreases. Anti-reaction valves (3) and (4) function in order to stop the swing movement of the upper structure with a slight reversed motion. The increased oil pressure in port (10) causes a shock load. The absorption of the shock load is described in the following manner.
In anti-reaction valve (3), plunger (24) and valve seat (23) separate from each other. Ball (33) is forced against plunger (24) by the pressure oil in port (10). Oil can now flow from port (10) through passages (20) and (31) to passage (8) .
In anti-reaction valve (4), plunger (16) and valve seat (14) separate from each other. Ball (30) is forced against valve seat (14) by the pressure oil in passage (29). The flow of oil from port (10) through passage (9) to passage (8) is blocked.
The oil pressure in port (10) decreases and the rotation of motor rotary group (5) is prevented. The swing movement is gradually stopped.