An angular contact ball bearings including a plurality of balls (disposed between an outer ring and an inner ring) and a cage holding these balls has been extensively used in a bearing device for supporting a differential case on a differential carrier (see JP-A-2004-211856) and other bearing devices.
Various rolling bearings have been required to have a lightweight design, and with respect to an angular contact ball bearing, it may be proposed to reduce an axial dimension of an outer ring and/or an inner ring in order to achieve a lightweight design. On the other hand, with respect to the angular contact ball bearing, it is a common practice to first prepare an outer ring assembly in which the outer ring, the cage and the balls are assembled together and then to assemble the ball bearing. However, the method of achieving the lightweight design by reducing the axial dimension of the outer ring has a problem that at the time of incorporating a ball-cage assembly, in which the balls and the cage are assembled together, into the outer ring, the balls are unstable and therefore are liable to move.
An angular contact ball bearing includes: an inner ring including a shoulder portion-side end surface; an outer ring which includes a counterbore-side smaller-diameter portion and a counterbore-side end surface disposed axially inwardly of the shoulder portion-side end surface of the inner ring; a plurality of balls arranged in a circular row between the outer ring and inner rings; a cage for holding the balls; and a cylindrical guide portion which is provided at and communicates with the counterbore-side smaller-diameter portion and guides a ball-cage assembly in which the balls and the cage are assembled together when the ball-cage assembly is inserted into the outer ring. When the ball-cage assembly is inserted into the outer ring disposed horizontally, the ball-cage assembly is supported by the counterbore-side smaller-diameter portion and is prevented from being inclined by the guide portion.