Internal gear oil pump for vehicles

Abstract

To provide a vehicle internal gear oil pump including a driven gear capable of obtaining a self-aligning effect of the driven gear while suppressing an increase in fluid friction acting on the driven gear. A concave first dynamic pressure generating groove (46c) is provided on the outer peripheral surface (46b) of the driven gear (46), and the depth D1 is set so that the pump The ratio of the gap H1 of the inner peripheral surface (34c) of the body (34) to the gap H2 from the outer peripheral surface (46b) of the driven gear (46) to the inner peripheral surface (34c), that is, the gap ratio m1, is within a predetermined range The predetermined range includes the maximum value of the dynamic pressure P1 generated by the first dynamic pressure generating groove (46c) and the minimum value of the fluid friction coefficient μ1 acting on the basis of the first dynamic pressure generating groove (46c). value. Therefore, the fluid friction coefficient μ1 acting on the driven gear (46) becomes the minimum and the dynamic pressure P1 generated in the first dynamic pressure generating groove (46c) becomes the maximum, and the fluid friction acting on the driven gear (46) can be suppressed. increase, while obtaining the self-aligning effect of the driven gear (46).

Description

Technical field [0001] The present invention relates to a vehicle internal gear type oil pump equipped with a driven gear, and more particularly to a technique for optimizing the depth of a plurality of grooves recessed in the outer peripheral surface of the driven gear. Background technique [0002] The internal gear oil pump for a vehicle is equipped with: (a) a pump chamber, which is formed by a pump body and a pump cover; (b) an annular driven gear, which has internal teeth and faces the inner peripheral surface forming the pump chamber And (c) a drive gear having external teeth meshing with the internal teeth of the driven gear and arranged to be able to circulate around the driven gear The rotation center of the eccentric rotation center rotates and drives the driven gear to rotate. For example, Patent Documents 1 and 2 are like this. [0003] Generally, in the above-mentioned internal gear type oil pump for a vehicle, when the rotation of the driven gear is stopped, the dr...

AI Technical Summary

Problems solved by technology

[0004] However, in the internal gear oil pump for vehicles as described above, for example, when rotating at a low speed and / or when high oil pressure is generated, there is a gap between the outer peripheral surface of the driven gear and the inner peripheral surface of the pump chamber. The balance of the dynamic pressure generated between them is not sufficient, and there is a problem that the driven gear is unstable or the rotation center of the driven gear is deflected (vibration れる).

The deflection of the center of rotation of the driven gear causes the lubrication state between the outer peripheral surface of the driven gear and the inner peripheral surface of the pump chamber to become a boundary lubrication state, resulting in friction loss and increased rotational resistance of the driven gear. Big

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