PULLER GP- 1U6415 - Caterpillar

Illustration 1 g03785827
(1) Medium pressure pilot pump Medium pressure pilot pump (1) is mounted the rear of the swing pump.Modes of Operation
Low Pressure - Standby
Illustration 2 g03785574
Low-pressure standby
(1) Line - to medium pressure pilot pump displacement solenoid
(2) Line - to pilot oil filter
(3) Pressure compensator valve
(4) Line - from medium pressure pilot pump displacement solenoid
(5) High-pressure cutoff valve
(6) Actuator piston
(7) Bias spring When, the engine is started and the pump has no demand. Bias spring (7) moves actuator piston (6) to the right, which holds the swashplate at maximum angle. When the pump displacement solenoid (on the pilot manifold) is not activated, pump flow is blocked and no signal pressure is generated through line (4). As the pump produces flow, the system pressure begins to increase. This pressure is felt at the left end of the flow compensator spool (3). The flow compensator spool moves against spring force and permits system oil to flow to the actuator piston.The actuator piston moves the swashplate to the "LOW PRESSURE STANDBY" position. In "LOW PRESSURE STANDBY", the pump produces enough flow to compensate for system leakage at sufficient pressure to provide instantaneous response when a function is performed.Upstroke
Illustration 3 g03785896
Upstroke
(1) Line - to medium pressure pilot pump displacement solenoid
(2) Line - to pilot oil filter
(3) Pressure compensator valve
(4) Line - from medium pressure pilot pump displacement solenoid
(5) High-pressure cutoff valve
(6) Actuator piston
(7) Bias spring During a function, signal pressure from the displacement solenoid through line (4) increases. This increased pressure causes the force (flow compensator valve spring plus oil pressure) at the right end of the flow compensator spool (3) to become greater than the pump supply pressure at the left end of the spool.The increased pressure at the right end of the flow compensator spool causes the spool to shift left. The spool reduces or blocks pump output oil flow to the actuator piston (6), and opens a passage to drain. Reducing or blocking oil flow to the actuator piston reduces or eliminates the pressure acting against the actuator piston. When the pressure in the actuator piston decreases, bias spring (7) moves the swashplate to a greater angle, and the pump upstrokes.Destroke
Illustration 4 g03785918
Destroke
(1) Line - to medium pressure pilot pump displacement solenoid
(2) Line - to pilot oil filter
(3) Pressure compensator valve
(4) Line - from medium pressure pilot pump displacement solenoid
(5) High-pressure cutoff valve
(6) Actuator piston
(7) Bias spring When the load on the medium pressure of pilot system decreases, signal oil pressure at the right end of flow compensator spool (3) decreases. This decreased pressure causes the force (flow compensator spool spring plus oil pressure) at the right end of the flow compensator spool to decrease below the pump supply pressure at the left end of the spool. The decreased pressure at the right end of the flow compensator spool causes the spool to shift. This action allows more flow to actuator piston (6), causing the pressure in the actuator piston to increase. The increased pressure in the actuator piston overcomes the combined force