Patent ID: 8956133
Filing Date: 2015-02-17
Classification: F04C,F16H

Abstract:
1. A vehicular internal gear type oil pump including: a drive gear that has outer peripheral teeth and that is provided rotatable about an axis; an annular driven gear that has inner peripheral teeth that mesh with the outer peripheral teeth of the drive gear and that is provided rotatable about an offset axis that is offset from the axis, and that is rotatably driven by the drive gear; a pump chamber inside of which the driven gear and the drive gear are housed; a housing that has a high pressure discharge passage and a low pressure discharge passage that are open, a predetermined distance apart from each other in a circumferential direction, to a side surface of the pump chamber, in order to discharge fluid from within the pump chamber, and wherein a plurality of hydraulic pressure chambers, that are formed in the circumferential direction by a mesh gap between the inner peripheral teeth and the outer peripheral teeth, move in a predetermined rotational direction as the drive gear and the driven gear rotate; wherein the hydraulic pressure chambers are communicated with the high pressure discharge passage and the low pressure discharge passage in a process in which the volume of the hydraulic pressure chambers is reduced; and a spill passage formed in a side surface of the pump chamber to communicate a predetermined hydraulic pressure chamber, from among the plurality of hydraulic pressure chambers, with the high pressure discharge passage when the entire predetermined hydraulic pressure chamber is positioned between the high pressure discharge passage and the low pressure discharge passage, wherein the high pressure discharge passage is provided behind, in the rotational direction, the low pressure discharge passage, and wherein the spill passage includes at least one of an outer circumferential groove or an inner circumferential groove, in which, when the entire predetermined hydraulic pressure chamber is positioned between the high pressure discharge passage and the low pressure discharge passage, the outer circumferential groove extends in the circumferential direction forward in the rotational direction from a radially outer side of a mesh position of the inner peripheral teeth and the outer peripheral teeth of a front end surface in the rotational direction of the high pressure discharge passage, and a tip end portion of the outer circumferential groove is communicated with the predetermined hydraulic pressure chamber, and the inner circumferential groove extends in the circumferential direction forward in the rotational direction from a radially inner side of the mesh position of the inner peripheral teeth and the outer peripheral teeth of the front end surface in the rotational direction of the high pressure discharge passage, and a tip end portion of the inner circumferential groove is communicated with the predetermined hydraulic pressure chamber.