Patent ID: 8257057
Filing Date: 2012-09-04
Classification: F04C

Abstract:
1. A variable displacement vane pump comprising: a rotor formed with a plurality of slots each having a backpressure chamber, and provided with a plurality of vanes each slidably received in one of the slots and arranged to be urged radially outwards by a pressure in the backpressure chamber; an annular cam ring receiving therein the rotor rotatably, the cam ring being arranged to swing, and to define a plurality of pumping chambers with the vanes between the rotor and the cam ring; a pump body encasing the cam ring and the rotor and including an end wall; a pressure plate disposed between the end wall of the pump body and the rotor, the pressure plate including: a first seal member which is provided between the backup surface and the end wall, the first seal member including: wherein the outlet-side segment of the first seal member includes an outer circumference including first and second convex portions, and a concave portion which is located circumferentially between the first and second convex portions, and which is recessed so that a radial distance from a center axis of the pressure plate is smaller at the concave portion than at the first and second convex portions.