Patent ID: 8113804
Filing Date: 2012-02-14
Classification: F01C,F04C

Abstract:
1. A vane pump comprising: a shaft driving a rotor, said rotor having a plurality of vane grooves, with a vane received in each of said plurality of vane grooves, and an under vane passage for communicating a pressurized fluid into said grooves to bias said vanes radially outwardly of said rotor; a cam ring positioned radially outwardly of said rotor, and said cam ring being free to rotate with said rotor through friction from said vanes as said rotor rotates; an inlet for delivering a fluid to be pumped into an inlet chamber, and a main outlet for receiving the fluid pumped by the vane pump; and an under vane outlet for the fluid in said grooves, said under vane outlet communicating to said main outlet through a passage including a valve to increase the pressure of the fluid in the grooves.