Ball bearing cages and ball bearings

With the ball bearing cage of the present invention, at least one of all the pockets has a protrusion projecting inwardly thereof from one of inner and outer circumferential edge portions of the pocket face. Therefore, in the case where a ball bearing is so assembled with use of the cage that the fixed ring is positioned alongside the circumferential edge portion having the protrusion, and when the rotatable ring of the bearing is rotated relative to the fixed ring, the edge portion of the pocket face close to the rotatable ring comes into contact with the ball at a front portion of the ring with respect to the direction of its rotation, and at this portion, the clearance between the pocket face and the ball gradually increases from the rotatable ring side toward the fixed ring side. Accordingly, at the front portion of the rotatable ring with respect to the direction of rotation of this ring, the lubricant adhering to the ball outside the pocket is partly scraped off by the pocket face edge portion adjacent to the rotatable ring. The portion of lubricant ingressing into the clearance rapidly passes through the clearance and egresses therefrom toward the fixed ring. Consequently, the clearance between the ball surface and the pocket face becomes approximately uniform from the rotatable ring side toward the fixed ring side, such that the sliding contact of the ball with the pocket face in the presence of lubricant encounters smaller resistance than in the conventional bearing wherein the lubricant is present therebetween. The reduction of the resistance to the sliding contact of the ball with the pocket face precludes production of noise. Additionally, the reduced resistance to the sliding contact lowers the torque required for the rotation of the ball bearing, further preventing the lubricant from becoming heated to a high temperature to give a prolonged life to the lubricant.

When the ball bearing cage is in the form of a crown, and the protrusion is formed at the innermost portion of the pocket, the protrusion precludes production of noise irrespective of the direction of rotation of the rotatable ring. If the protrusion is not positioned at the innermost portion of the pocket, it is only when the rotatable ring is rotated in one direction that the production of noise can be prevented.

In the case where the ball bearing cage is a ribbon-type pressed cage, or an annular molded cage wherein the plurality of pockets are each in the form of a through hole, and the protrusion is formed at one end of the pocket with respect to the axial direction of the cage, the protrusion precludes production of noise regardless of the direction of rotation of the rotatable ring. If the protrusion is not positioned at the end of the pocket, it is only when the rotatable ring is rotated in one direction that the production of noise can be precluded.

When the protrusion in the ball bearing cage is formed at each of opposite sides of a plane extending through the center of the pocket and parallel to the axis of the cage, the protrusions preclude production of noise regardless of the direction of rotation of the rotatable ring.

In the ball bearing of the invention, the cage is formed with a plurality of pockets each having an inwardly curved spherical pocket face similar to the ball of the bearing in shape, at least one of all the pockets having a protrusion projecting inwardly thereof from an edge portion of the pocket face close to the fixed one of the inner and outer rings of the bearing. When the rotatable one of these rings is rotated relative to the fixed ring, the edge portion of the pocket face close to the rotatable ring contacts the ball at a front portion of the ring with respect to the direction of rotation thereof, and at this portion, the clearance between the pocket face and the ball gradually increases from the rotatable ring side toward the fixed ring side. Accordingly, at the front portion of the rotatable ring with respect to the direction of rotation of this ring, the lubricant adhering to the ball outside the pocket is partly scraped off by the pocket face edge portion adjacent to the rotatable ring. The portion of lubricant ingressing into the clearance rapidly passes through the clearance and egresses therefrom toward the fixed ring. Consequently, the clearance between the ball surface and the pocket face becomes approximately uniform from the rotatable ring side toward the fixed ring side, such that the sliding contact of the ball with the pocket face in the presence of lubricant encounters smaller resistance than in the conventional bearing wherein the lubricant is present therebetween. The reduction of the resistance to the sliding contact of the ball with the pocket face precludes production of noise. Additionally, the reduced resistance to the sliding contact lowers the torque required for the rotation of the ball bearing, further preventing the lubricant from becoming heated to a high temperature to give a prolonged life to the lubricant.