Patent ID: 6024550
Filing Date: 2000-02-15
Classification: F04C

Abstract:
An oil pump of the type which includes a pump housing formed with an axial bore for support of an input shaft and with a cylindrical recess the center of which is eccentrically displaced from the center of the axial bore, an inner rotor formed at its inner periphery with at least a pair of diametrically opposed radial projections for engagement with the input shaft disposed in the axial bore and at its outer periphery with a plurality of external teeth and being mounted on the input shaft within the pump housing for rotation therewith in a condition where opposite side faces of the inner rotor are slidably in contact with a pair of axially opposed internal side faces of the pump housing, and an outer rotor formed at its inner periphery with a plurality of internal teeth for engagement with the external teeth of the inner rotor and being coupled within the cylindrical recess of the pump housing, wherein the diametrically opposed radial projections of said inner rotor each are integrally formed at their one ends with an axial protrusion slightly smaller in diameter than the axial bore of the pump housing to be coupled within the axial bore of said pump housing for positioning said inner rotor in place without causing any frictional contact with the inner peripheral surface of the axial bore during rotation of the inner rotor.