| 主权项 |
1. A vane pump comprising:
a housing including first and second side walls confronting each other and having therein an inside chamber to receive a pump element; a drive shaft which extends in an axial direction and which is received rotatably in first and second through holes formed, respectively, in the first and second side walls of the housing; a rotor mounted on the drive shaft and arranged to be driven rotationally by the drive shaft, and to serve as at least part of the pump element, the rotor including a first annular groove formed in a first axial end surface of the rotor, and a second annular groove formed in a second axial end surface of the rotor; a plurality of vanes received, respectively, in a plurality of slits formed radially in an outer circumferential portion of the rotor and arranged to slide radially in the slits, respectively; first and second guide rings received, respectively, in the first and second annular grooves and arranged to push the vanes radially outwards in the slits in accordance with rotation of the rotor; the rotor including
a cylindrical portion which is formed integrally on a radial inner side of the first annular groove, and which projects in the axial direction from the first axial end surface, along the drive shaft, anda slide contact portion formed on a radial inner side of the second annular groove in the second end surface;an outside circumferential surface of the cylindrical portion of the rotor being slidably disposed in an inside circumferential surface of the first through hole of the first side wall of the housing, whereas the slide contact portion of the rotor includes a slide contact surface abutting slidably on an inside wall surface of the second side wall of the housing;a pressure receiving area in the axial direction, of one of the first and second annular grooves being set greater than a pressure receiving area in the axial direction, of the other of the first and second annular grooves. |
