| |
| Illustration 1 | g06018751 |
|
Swing motor (6) Anti-reaction valve | |
Anti-reaction valve (6) is an integrated valve within the swing motor head. The anti-reaction valve is used to reduce the reverse swing effect when the swing operation is stopped.
At a stop of swing operation, it is difficult to smoothly stop the upper structure and implements at the desired position due to the mass (weight and size) of the upper structure. The pressure of the blocked oil in the outlet side of the swing motor goes back to the motor rotary group. The upper structure begins to swing in the opposite direction. Anti-reaction valve (6) prevents the blocked oil from flowing back to the motor rotary group.
| |
| Illustration 2 | g06018752 |
|
Anti-reaction valve (neutral position) (1) Orifice (2) Valve (3) Chamber (4) Passage (5) Spring (6) Anti-reaction valve (7) Passage (8) Passage (9) Passage (10) Passage (11) Spring (12) Valve (13) Passage (14) Chamber (15) Valve (16) Orifice (17) Piston (18) Swing control valve (19) Idler pump | |
During a swing operation of the upper structure, the oil delivery from idler pump (19) flows through swing control valve (18) to the motor rotary group. When the swing joystick is in the NEUTRAL position, the swing control valve is in the NEUTRAL position. The oil delivery from the idler 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.
Valve (12) is centered by spring (5) and spring (11). Valve (12) controls the oil flow between orifice (1) and (16) during swing start and swing stop operations. Piston (17) is connected to valve (12).
| |
| Illustration 3 | g06018756 |
|
Anti-reaction valve (start of swing operation) (1) Orifice (2) Valve (3) Chamber (4) Passage (5) Spring (6) Anti-reaction valve (7) Passage (8) Passage (9) Passage (10) Passage (11) Spring (12) Valve (13) Passage (14) Chamber (15) Valve (16) Orifice (17) Piston (18) Swing control valve (19) Idler pump | |
When the swing joystick is moved from the NEUTRAL position in order to perform a swing operation, swing control valve (18) shifts. The oil delivery from idler pump (19) flows through swing control valve (18).
As the motor rotary group gets pump oil through passage (10), the motor rotary group begins to rotate clockwise. The oil in passage (9) flows through valve (12), passage (13), and into orifice (16). Oil then flows through valve (15) and into chamber (14).
Due to the increased pressure on the right end of valve (12), the oil pressure in chamber (14) begins to move piston (17) to the left. Office (1) restricts oil flow in chamber (3). This action dampens the valve movement.
| |
| Illustration 4 | g06018758 |
|
Anti-reaction valve (constant swing operation) (1) Orifice (2) Valve (3) Chamber (4) Passage (5) Spring (6) Anti-reaction valve (7) Passage (8) Passage (9) Passage (10) Passage (11) Spring (12) Valve (13) Passage (14) Chamber (15) Valve (16) Orifice (17) Piston (18) Swing control valve (19) Idler pump | |
Once the upper structure begins to swing, valve (12) shifts fully to the left from the pressure in passage (9) and from piston (17) shifting to the left. Piston (17) is directly connected to valve (12). High pressure oil from passage (10) cannot flow to return passage (7) through valve (12). No dampening effect is occurring.
| |
| Illustration 5 | g06018759 |
|
Anti-reaction valve (swing stop operation) (1) Orifice (2) Valve (3) Chamber (4) Passage (5) Spring (6) Anti-reaction valve (7) Passage (8) Passage (9) Passage (10) Passage (11) Spring (12) Valve (13) Passage (14) Chamber (15) Valve (16) Orifice (17) Piston (18) Swing control valve (19) Idler pump | |
When the swing joystick is returned to the NEUTRAL position, the oil delivery from idler pump (19) to the motor rotary group is blocked. This blockage occurs at swing control valve (18). 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 (7) increases. The oil pressure in passage (10) decreases.
The increased oil pressure in passage (7) flows through passage (4), and into orifice (1). Oil then flows into chamber (3). Due to the increased pressure on the left end of piston (17), piston (17) and valve (12) shifts to the right. Orifice (16) restricts oil flow coming from chamber (14). This action dampens the valve movement.
Since passages (7) and (10) are connected by anti-reaction valve (12), 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.
| |
| Illustration 6 | g06018761 |
|
Anti-reaction valve (reverse rotation) (1) Orifice (2) Valve (3) Chamber (4) Passage (5) Spring (6) Anti-reaction valve (7) Passage (8) Passage (9) Passage (10) Passage (11) Spring (12) Valve (13) Passage (14) Chamber (15) Valve (16) Orifice (17) Piston (18) Swing control valve (19) Idler pump | |
As there is no mass (weight and size) of the upper structure, the motor rotary group stops. Immediately after the motor has stopped, the motor rotary group slightly rotates in the counterclockwise direction due to gear backlash. Now, the oil pressure in passage (10) increases and the oil pressure in passage (7) decreases. The increased oil pressure from passage (10) attempts to move valve (12) to the left against spring (5). Since the oil flow to passage (10) is restricted at orifice (16), piston (17) moves slowly. Then, the oil flows from passage (10) to passage (7) though valve (12). This action equalizes the pressure in passage (7) and in passage (10). Now valve (12) is kept at this balancing position. The upper structure and each implement can stop smoothly.