ROLLING BEARING

摘要

A rolling bearing having a long life and used for, e.g. a vacuum pump under severe conditions of low-pressure atmosphere, high-speed rotation, high temperature, fluorine lubricant lubrication. A full complement angular ball bearing (with no retainer) the contact angle of which is 10 to 45 DEG , preferably 15 to 30 DEG is used. Therefore, the number of balls is large, the contact pressure between the inner and outer rings and the balls is low, and the degree of spin slip due to the fluctuating load is reduced, thereby decreasing the wear. The surface roughensses of the inner and outer rings are restricted, the ratios of the roughensses to the rolling elements are restricted, the content of Cr in the alloy steel of the rolling elements is restricted, the rolling elements are made of an oxide ceramic or a dense nitride layer is formed on the surface of the rolling elements, any foreign matters the average diameter of which exceeds 3 mu m are prevented from being present on the raceway surfaces of the outer and inner rings, and a coating harder than the raceway surfaces of the outer and inner rings is provided on the surfaces of the rolling elements. As a result, the life of the rolling bearing is prolonged.