A vane pump assembly including a cam ring having an elliptical inner bore
defining a hydraulic pumping chamber, the pumping chamber having an
interior camming surface. The cam ring defines ports for admitting fluid
into the pumping chamber. A rotor, within the cam ring, defines a
plurality of radial vane slots. A vane assembly is supported in each vane
slot to define vane buckets. Each vane assembly has an end dynamic vane
seal for reducing leakage between the buckets. Front and rear side
plates, separated by an annular spacer, enclose the pumping chamber. The
pump assembly may also include floating front and rear rotor seals for
reducing radially inward leakage. Each rotor seal is disposed within a
groove formed in the rotor, wherein discharge pressure urges the rotor
seals axially outward from the pumping chamber to create an effective
seal against the respective side plate.