Bearing ball cage and method of making the same

摘要

A cage for a ball bearing assembly has a pocket for accommodating one of the balls defined at a plurality of locations in a direction circumferentially thereof and each of the pockets has an inner surface so shaped as to represent a concaved spherical surface. A concaved portion extending from an open edge on the cage inner diametric side towards the cage outer diametric side is provided in an inner surface of each of the pockets. The sectional shape of the inner surface of this concaved portion in a cage circumferential direction is represented by an arcuate shape of a radius of curvature smaller than the radius of curvature of the concaved spherical surface defining the inner surface of the respective pocket. The inner surface of each of the pockets may be formed with a film.