Patent ID: 7427191
Filing Date: 2008-09-23
Classification: F04C,F16N

Abstract:
1. An oil pump comprising; a cam ring, an outer rotor having inner teeth, which is rotatably provided inside of the cam ring, an inner rotor having outer teeth, which is engageable with the inner teeth of the outer rotor, a drive shaft which rotatably drives the inner rotor, a first housing and a second housing which are provided at opposite ends of the cam ring, a plurality of volume chambers which are formed between the inner teeth of the outer rotor and the outer teeth of the inner rotor, a first axial hole, which is formed in the cam ring and is positioned corresponding to a mesh portion having a minimum volume of the volume chambers, a second axial hole, which is formed in the cam ring and is positioned corresponding to a trap portion having a maximum volume of the volume chambers, a suction port and a discharge port, which are formed at least in one of said first and second housings and are open to the volume chambers between the mesh portion and the trap portion, are positioned at a line symmetry of an axis line between the mesh portion and the trap portion, a first dowel pin inserted into the first housing, the second housing and the first axial hole, and a second dowel pin inserted into the first housing, the second housing and the second axial hole, the suction port and the discharge port are reversed depending on a rotary direction of the drive shaft, wherein at least one of the first and second axial holes is formed as a slot extending along the axis line.