Oil pump having a sealing mechanism for a pumping chamber

摘要

In an oil pump having an inner rotor and an outer rotor supported in a housing, pressure in a pumping chamber whose volume is at maximum presses the inner rotor inwardly and the outer rotor outwardly. An oil groove which communicates with a discharge port via a lubricating groove is formed in an inner surface of the housing at the circumferential position of the pumping chamber whose volume is at maximum. The oil groove has axial sealing surfaces.