SHEET AS 1858554 - Caterpillar

Illustration 4 g00277934
Metering PositionIn the metering position, pump pressure is greater than the combined force of spring (2) and the signal pressure in cavity (3) . Spool (5) moves up.Pressure is now sent to actuator piston (8) . This pressure is greater than the force that is moving swashplate (15) toward the maximum angle. The angle of swashplate (15) decreases and pump output decreases.When the pump pressure is reduced enough, the combined force of the signal pressure and of the spring in cavity (3) will cause spool (5) to move down. The oil pressure behind actuator piston (8) flows to the case drain.Slight up and down spool movement is called metering. Metering maintains equal force on both ends of spool (5) . The pressure of spring (2) is equal to 2100 kPa (305 psi). The pump pressure is 2100 kPa (305 psi) greater than the signal pressure. The difference is called the margin pressure.Destroking
Illustration 5 g00280127
Operation of the Pump and the Compensator (1) Pressure compensator spring. (2) Flow compensator spring. (3) Cavity. (4) Signal line. (5) Flow compensator spool. (6) Check valve. (7) Passage. (8) Actuator piston. (9) Signal line from metering pump. (10) Pressure line to metering pump. (11)