Patent ID: 7226281

Claim:
A vane pump for compressing or decompressing fluid, comprising: a casing having a cylindrical inner bore; a rotor disposed in the inner bore with an eccentric ration thereto, forming a circular pump chamber between the inner bore and the rotor; and vanes slidably held in the rotor so that one end of each vane slidably contacts the inner bore by a centrifugal force generated by rotation of the rotor, the circular pump chamber being divided by the vanes to thereby form pump chambers each having a capacity changing according to rotation of the rotor, wherein: the vanes are disposed in grooves formed in the rotor to be movable in the grooves in axial and radial directions of the rotor; the grooves are slanted with respect to a rotational axis of the rotor; and the vane has a parallelogram cross-section taken along a plane parallel to the rotational axis of the rotor.