AXIAL PISTON PUMP FEATURING ANGLED FILL PORTS AND NOISE-REDUCING RELIEF PORTS

摘要

A variable displacement axial piston pump has a plurality of piston bores each connected to an inwardly angled fill port. The fill ports extend from the piston bores inwardly to the working face of the barrel to reduce the diameter of the fill circle of a pump. This decreases the velocity that must be attained by incoming fluid to thereby increase the operating speed at which the pump may be driven where the pump is filled at atmospheric pressure. A pair of staged bleed ports are inserted in the port plate between the fluid inlet port and the fluid outlet port to provide a staged transition for the fluid in the fill ports as these ports move from fluid communication with the fluid inlet port to fluid communication with the fluid outlet port. Additionally, ports are formed in the surface of the port plate one of which is connected to the pressure port and the other of which is connected to case to dissipate energy within the fill port prior to the time the fill port encounters the suction port of the port plate.