Patent ID: 8684712
Filing Date: 2014-04-01
Classification: F04C,F05C

Abstract:
1. An internal gear oil pump for a vehicle, comprising: a pump body that has a pump chamber formed by a cylindrical inner peripheral surface; a driven gear that has an annular shape, that has internal teeth, and is rotatably supported by the cylindrical inner peripheral surface by fitting with the cylindrical inner peripheral surface; and a drive gear that has external teeth that mesh with the internal teeth of the driven gear, is rotatably provided about a rotational center that is offset from the rotational center of the driven gear, and rotatably drives the driven gear, wherein: a plurality of convex portions that protrude radially outward from a plurality of positions separated in a circumferential direction are formed on an outer peripheral surface of the driven gear; each convex portion has, in the circumferential direction of the driven gear, a rising surface that rises from a minimum diameter position to a maximum diameter position in a direction opposite a rotational direction of the driven gear, and a falling surface that falls from the maximum diameter position to the minimum diameter position that is adjacent to and in back of the maximum diameter position with respect to the rotational direction of the driven gear; and a circumferential length of the falling surface is greater than a circumferential length of the rising surface.