Pulley ball bearing and pulley

摘要

A ball bearing for a pulley that is a component of a wrapping connector transmission device installed to an engine for an automobile. In the bearing, the depths of ball grooves formed in the inner ring and the outer ring of the ball bearing are set so that the risk rate of the ball being stranded on the shoulder becomes approximately the same for the inner ring and the outer ring under pure thrust load. Furthermore, the depth of the ball groove of the outer ring is set shallower than the depth of the ball groove of the inner ring. The depth of the ball groove of the outer ring is set in a range of 12-19% of the diameter of the ball.