Abstract: A rotor for an oil pump according to the present invention is a rotor that includes an inner rotor configured by teeth, each of which has a plurality of ellipses or circles, and an outer rotor that is disposed on the outside of the inner rotor and has one tooth more than the inner rotor, wherein, in a tooth of the inner rotor, a tooth top and a tooth root of a drive-side half-tooth region extending from the tooth top to the tooth root and a tooth top and a tooth root of a non-drive-side half-tooth region extending from the tooth top to the tooth root are each configured by a different ellipse or a circle. A circumferential axis along a circumferential direction of the ellipse or circle configuring the tooth top is longer in the non-drive-side half-tooth region than in the drive-side half-tooth region.

Abstract: An oil pump is increased to inhibit noise generation and durability is also improved. The oil pump includes a pump body, an inner rotor having outer teeth, and an outer rotor having inner teeth. A maximum partition portion is formed between a trailing end side of an intake port and a leading end side of a discharge port in a rotor chamber of the pump body. Among cells constituted by the outer teeth of the inner rotor and the inner teeth of the outer rotor, a central cell positioned in the location of the maximum partition portion and adjacent cells positioned before and after the central cell in the direction of rotation are sealed by mutual contact of the outer teeth and the inner teeth. The outer teeth and the inner teeth constituting cells other than the central cell and adjacent cells are not in contact with each other.

Abstract: An oil pump includes: a rotor chamber; an outer rotor; and an inner rotor. A partition surface between a starting end side of the intake port and a terminal end side of the discharge port is set as a first seal land. An intake groove portion that projects from the starting end side of the intake port toward the terminal end side of the discharge port and a discharge groove portion that projects from the terminal end side of the discharge port toward the starting end side of the intake port are formed in positions which are located on the first seal land. The intake groove portion and the discharge groove portion are provided in intermediate tooth height direction positions of a meshing location between the inner rotor and the outer rotor.

Abstract: The invention has: a housing; a pump section formed of a drive gear unit and a driven gear unit; a main flow channel through which oil pressure is applied to the driven gear unit in a discharge volume reduction direction; a first branching flow channel through which oil pressure that assists oil pressure from the main flow channel is applied; a second branching flow channel through which oil pressure is applied to the driven gear unit in a discharge increase direction; a first flow channel control section; a second flow channel control section; and a spring that elastically urges the driven gear unit in a discharge increase direction. The first flow channel control section and the second flow channel control section can perform switching control in accordance with each increase or decrease of engine revolutions and in pressure.