Patent ID: 7896631

Claim:
A vane pump comprising: a housing having a longitudinal axis and an approximately circular pump room with a center; a rotor which rotates at an eccentric position relative to the center of the pump room, the rotor comprising a rotor portion for holding a vane; a shank for rotationally driving the rotor portion; a bearing for supporting the shank, the bearing being located in the housing and having an inner surface; a vane rotated by the rotor and dividing the pump room into a plurality of spaces; an oil supply passage in intermittent communication with the pump room due to the rotation of the rotor, the oil supply passage comprising an oil supply groove on the inner surface of the bearing, the oil supply groove extending in the axial direction and being in fluid communication with the pump room, and comprising an oil conveyance passage located in the shank, the oil conveyance passage having a branching passage adjacent the pump room and configured such that when the branching passage aligns with the oil supply groove as the rotor rotates, the branching passage is in fluid communication with the oil supply groove and lubricating oil may be fed into the pump room; and an air passage for providing communication between the pump room and air outside of the housing when the oil supply passage is in communication with the pump room by rotation of the rotor, the air passage comprising an open air passage and an open air groove, the open air groove being disposed on the inner surface of the bearing at a different location in the circumferential direction relative to the oil supply groove, the open air passage being disposed at a location in the shank more remote from the pump room than the branching passage and extending in a different circumferential direction relative to the branching passage, the open air passage being smaller in diameter than the branching passage, in communication with the oil conveyance passage and capable of communicating with the open air groove, the vane pump being configured such that when the branching passage aligns with the oil supply groove, the open air passage of the air passage communicates with the open air groove and the pump room communicates with the air outside of the housing.