Structure for preventing cavitation erosion of oil pump

摘要

A Structure of an oil pump for preventing occurrence of cavitation erosion on a region of the very small side gap between the side face of the pump gear and the side wall face of the pump case without reduction in volumetric efficiency of the pump can be provided. A side face of the pump gear is formed into a stepped face such that an annular region extending radially from a diameter which is smaller than the dedendum circle diameter of the pump gear and larger than the outer diameter of a pump gear bearing to the addendum circle diameter of the pump gear is recessed by a certain depth to increase said side gap in said recessed annular region so that said side gap in said recessed annular region is larger than a side gap in a region between said diameter smaller than the dedendum circle diameter of the pump gear and larger than the outer diameter of the pump gear bearing to the outer diameter of the pump gear bearing.