BUCKET GP-MULTIPURPOSE 1121924 - Caterpillar

Illustration 1 g00768473
Pressure and Flow Compensator (Cushion-Hitch) (1) Flow compensator spool (2) Springs (3) Setscrew (4) Pressure compensator spool (5) Passage from the outlet opening of the piston pump (cushion-hitch) (6) Passage to the control piston of the piston pump (cushion-hitch) (7) Drain passage (8) Springs (9) SetscrewThe pressure and the flow compensator is set to function only as a pressure compensator. Setscrew (3) is set so that the flow compensator does not function.The pressure compensator regulates the output flow of the cushion-hitch piston pump. The output of the pump is controlled by the angle of the swashplate.When the engine is operating and the oil pressure in the cushion-hitch hydraulic system is less than the pressure setting of the pressure compensator, the oil from the outlet opening of the piston pump flows through passage (5). The oil is stopped by spool (4) and opposing force from springs (8). There is no flow to the control piston in the piston pump and the swashplate is at the maximum angle. When the system pressure setting has been obtained, full pump output is no longer needed. Full pump output from the pump continues, until the oil in passage (5) overcomes the opposing force of springs (8) .The oil in passage (5) moves pressure compensator spool (4) to the right. The oil in the inlet passage now flows through passage (6) into the control piston in the piston pump. The flow of oil from passage (6) moves the control piston. The control piston moves the swashplate toward the minimum angle. The pump output is decreased.The stroke of pistons in the piston pump are shortened since the slippers follow the reduced swashplate angle. The shortened stroke of the pistons will continue to provide enough flow in order to maintain the system pressure setting. The shortened stroke of the pistons will also provide internal lubrication to the pump components. When the pressure of the oil in the cushion-hitch hydraulic system decreases, there is a decrease in the pressure of the oil in passage (5). Springs (8) move spool (4) to the left. The oil flow to the control piston in passage (6) decreases. The spring in the piston moves the swashplate toward the maximum angle. The pump output is increased.