TUBE AS 4501025 - Caterpillar

When the swing control is in the NEUTRAL position, pump oil is not supplied to motor rotary group (5). Plunger (24) is located in anti-reaction valve (3). Plunger (24) shifts downward because of the force of spring (25). Plunger (24) is stopped by piston (26). Valve seat (23) shifts downward by the force of spring (22). Valve seat (23) comes in contact with plunger (24). Plunger (16) and valve seat (14) in anti-reaction valve (4) are shifted downward by the force of spring (13). The shift is stopped by piston (34). Valve seat (14) shifts downward by the force of spring (13). The shift is stopped when the top of valve seat (14) comes in contact with plunger (16) .When the swing control is activated, swing motor rotary group (5) receives pump oil from port (11) in block (1). Pump oil from port (11) flows through passages (10) and (12), and rotary group (5). Pump oil also flows through passages (6) and (8), and port (7). Therefore, motor rotary group (5) rotates counterclockwise.When the swing control lever is returned to the NEUTRAL position, oil flow from passage (10) is blocked to motor rotary groups (5). Motor rotary group (5) still continues to rotate counterclockwise because of the motion of the upper structure. The oil pressure which is blocked in passage (8) increases. The oil pressure in passage (10) decreases. The increased oil pressure in passage (8) then enters anti-reaction valve (4). The oil flows through passages (15) and (17). The oil flows into piston chamber (19). The oil pressure in piston chamber (19) moves plunger (16) upward against the force of spring (18). Valve seat (14) shifts upward against the force of spring (13) .Part of the increased oil pressure in passage (8) flows through passage (31). The oil enters anti-reaction valve (3). The oil then flows through passage (20) and into spring chamber (21). The oil shifts plunger (24) and valve seat (23) upward against the forces of springs (25) and (22).
Illustration 8 g00303370
Anti-reaction valve (inactive swing motor) (3) Anti-reaction valve (4) Anti-reaction valve (5) Motor rotary group (7) Port (8) Passage (9) Passage (10) Passage (11) Port (13) Spring (14) Valve seat (15) Passage (16) Plunger (18) Spring (19) Piston chamber (20) Passage (21) Spring chamber (22) Spring (23) Valve seat (24) Plunger (25) Spring (27) Orifice (28) Valve chamber (29) Passage (30) Ball (31) Passage (32) Orifice (33) BallWhen the motor attempts to stop, the oil pressure in passage (8) decreases. The oil pressure decreases in piston chamber (19). Spring (18) shifts down plunger (16). Spring (13) shifts down valve seat (14). Because the oil flow from valve chamber (28) is restricted by orifice (27), valve seat (14) moves more slowly than plunger (16). Plunger (16) and valve seat (14) separate from each other. Ball (30) is forced against the top end surface of plunger (16) by the oil pressure from passage (15). This opens the connection between passage (8) and (10) through passages (29) and