Patent ID: 6544013
Filing Date: 2003-04-08
Classification: F04C

Abstract:
An oil pump apparatus comprising:an oil pump housing including a first suction port, a second suction port and a discharge port in the circumferential direction thereof; a drive rotor and a driven rotor disposed rotatably eccentrically in a oil pump housing and forming a plurality of pump chambers in the circumferential direction of a rotor; and each of the pump chambers communicating to the first suction port, the second suction port and the discharge port in order, respectively when the drive rotor and the driven rotor are rotated; wherein a shape of an end portion in the anti-rotational direction of the second suction port is formed so as to be along a shape of a first end portion in the rotational direction of one of the pump chambers which is sealed momentarily between the first suction port and the second suction port, and a shape of an inner circumferential end portion of the first suction port is formed so as to be along a rotational trace of a second end portion in the anti-rotational direction of said one of the pump chambers, the rotational trace of the second end portion is composed of a plurality of contact points of the drive rotor and the driven rotor, and wherein a plural first pockets, which are selectively communicated to the first suction port at an outer circumferential portion thereof and which are not communicated to each port at the same time, are formed on the driven rotor, and a second pocket, which is located on an inner circumferential portion of the pump housing and closer to the drive rotor than the first suction port, is selectively communicated to said one of the pump chambers and the first suction port via an inner circumferential portion of one of the first pockets when said one of the pump chambers is communicated to the first suction port.