Patent ID: 6203303
Filing Date: 2001-03-20
Classification: F01C,F04C

Abstract:
A vane pump comprising:a rotor that is rotatably disposed in a cam ring attached to a housing;a plurality of vanes that are slidably disposed in corresponding slits formed in the rotor, said vane is configured to projected from the slit upon rotation of the rotor;a pair of sidewall members that close both side portions of the cam ring to form a cavity defined by the cam ring and said sidewall members;a plurality of annular backpressure grooves that are depressively formed on contact surfaces of said sidewall members with the rotor, adjacent two of the backpressure grooves are configured to be communicated with each other through a communication passage to introduce discharged pressure into an inside end portion of each of the slits; anddepressions that are formed on at least one of the contact surfaces of with said side wall members of the rotor, said depressions are configured to not contact a part of side surface of each of the vanes.