Patent ID: 7083394

Claim:
A vane pump comprising: a housing having an interior chamber with a rotor rotatably mounted therein; a cam pivotally mounted about the rotor and defining a pumping chamber within the interior chamber, the pumping chamber having an inlet arc region, a discharge arc region and sealing arc regions angularly extending at least about 30 degrees positioned between the inlet and discharge arc regions; a plurality of vane elements slideably supported within a plurality of radially extending slots formed in the rotor such that as the rotor rotates a radially outward centrifugal force is imparted to each vane element, wherein in the sealing arc regions the radially outward centrifugal force positions the vane elements radially outward; a sideplate mounted within the interior chamber having first and second opposing surfaces, the first surface being disposed adjacent the rotor of the vane pump, the first surface defining channels in fluid communication with the inlet and discharge arc regions for supplying pressurized fluid within the plurality of radially extending slots for providing an undervane force to balance each vane element so as to balance forces imparted thereon when each vane element is in the sealing arc region.