Abstract: An internal gear pump includes in a pump housing an outer rotor including an internal gear portion on the inner periphery, and an inner rotor being eccentrically disposed with respect to the outer rotor and including an external gear portion on the outer periphery that is engaged with the internal gear portion of the outer rotor. A side plate is integrated with the outer rotor to abut on a side of the inner rotor that fails to be in slide contact with the housing. A holding device is mounted to the pump housing to restrict a position of the outer rotor with respect to the housing.

Abstract: A rotor-type oil pump for sucking and discharging oil to be supplied to a variety of oil-requiring parts of an automotive engine. The oil pump comprises a generally annular outer rotor which is rotatably disposed in a pump casing. A generally annular inner rotor is disposed eccentrically inside the outer rotor and has an external gear which is partly in mesh with the internal gear of the outer rotor. The outer rotor is designed such that stress at the tooth base section of the internal gear is generally equal to stress at the tooth base section of the external gear of the inner rotor in their dynamic condition, thereby reducing the thickness of the tooth base section of the outer rotor.

Abstract: An oil pump comprises a housing, a cover, an inner gear having external teeth and a recess, and an outer gear having internal teeth engaged with the external teeth of the inner gear. The housing or the cover includes an engagement protrusion to be engaged with the recess of the inner gear for supporting the inner gear during assembly.

Abstract: A variable intake- and/or exhaust-valve timing control system for an internal combustion engine comprises a cam sprocket having a driven connection with an engine crankshaft, a camshaft, a ring gear provided between the camshaft and the cam sprocket for adjusting a relative phase angle between the cam sprocket and the camshaft, and a ring gear drive mechanism for drivingly controlling the ring gear via fluid pressure created by an engine oil pump, depending upon the operating state of the engine. The drive mechanism includes a subsidiary oil pump for supplying a fluid pressure greater than a designated pressure level to the ring gear, during low engine speed and high engine load.