Patent ID: 8414192
Filing Date: 2013-04-09
Classification: F16C

Abstract:
1. A cage for a ball bearing, comprising: a synthetic resin in which cage pockets for accommodating balls, respectively, formed as through holes penetrating through a radial direction are arranged on a circumference of said cage, and being formed by connecting a plurality of curved segments each of which comprises a curved shape in a circumferential direction; a pair of outer circumferential guiding convexes which protrude outwardly in the radial direction from the curved segments are provided on opposing edges of outer circumferential openings of certain cage pockets, and outer circumferential guiding faces for limiting radially inward displacement of the curved segments with respect to a pitch circle diameter of said balls are provided on said pair of outer circumferential guiding convexes; and a pair of inner circumferential guiding convexes which protrude inwardly in the radial direction from the curved segments are provided on opposing edges of inner circumferential openings of other cage pockets, and inner circumferential guiding faces for limiting a radially outward displacement of the curved segments with respect to the pitch circle diameter of said balls are provided on said pair of inner circumferential guiding convexes, wherein the outer circumferential guiding faces of said certain cage pockets and the inner circumferential guiding faces of said other cage pockets are alternately provided on each adjacent pair of said cage pockets along the circumference, wherein a pair of opposite inner circumferential stoppers for stopping come-off of said balls are provided on opposing sides in a circumferential direction in an inner circumferential opening of each of said certain cage pockets which has the outer circumferential guiding faces on the outer circumferential opening, and an interval between said pair of opposite inner circumferential stoppers becomes gradually narrow inwardly in the radial direction of the cage to stop come-off of the ball toward an inner circumferential side, said opposite inner circumferential stoppers including a surface facing the pocket and a surface opposite to the pocket in the circumferential direction both of which approach the pocket in the circumferential direction as the surface facing the pocket and the surface opposite to the pocket project inwardly in the radial direction from the curved segments, a surface facing the pocket in each of the opposite inner circumferential stoppers projects toward the pocket when the surface goes to a radial inner side, and a chamfered flat surface that is apart from a surface of the ball in the pocket is located on the radial inner side of the surface facing the pocket, wherein a pair of opposite outer circumferential stoppers for stopping come-off of said balls are provided on opposing sides in the circumferential direction in an outer circumferential opening of each of the other cage pockets which has the inner circumferential guiding faces on the inner circumferential opening, and an interval between the pair of opposite outer circumferential stoppers becomes gradually narrow outwardly in the radial direction of the cage to stop come-off of the ball toward an outer circumferential side, said opposite outer circumferential stoppers having a surface facing the pocket and a surface opposite to the pocket in the circumferential direction both of which approach the pocket in the circumferential direction as the surface facing the pocket and the surface opposite to the pocket project outwardly in the radial direction from the curved segments, a surface facing the pocket in each of the opposite outer circumferential stoppers projects toward the pocket when the surface goes to a radial outer side, and a chamfered flat surface that is apart from a surface of the ball in the pocket is located on the radial outer side of the surface facing the pocket, wherein the outer circumferential guiding convexes and the outer circumferential stoppers which are adjacent each other in the circumferential direction protrude from an outer circumferential surface of the curved segments independently, wherein the inner circumferential guiding convexes and the inner circumferential stoppers which are adjacent each other in the circumferential direction protrude from an inner circumferential surface of the curved segments independently; wherein a length in the circumferential direction of the outer circumferential guiding convex is longer than that of the outer circumferential stopper, a maximum height in the radial direction from the outer circumferential surface of the curved segment of the outer circumferential guiding convex is higher than that of the outer circumferential stopper, and an axial length of the outer circumferential guiding convex is longer than that of the outer circumferential stopper, wherein a length in the circumferential direction of the inner circumferential guiding convex is longer than that of the inner circumferential stopper, a maximum height in the radial direction from the inner circumferential surface of the curved segment of the inner circumferential guiding convex is higher than that of the inner circumferential stopper, and an axial length of the inner circumferential guiding convex is longer than that of the inner circumferential stopper, and wherein a segment of the outer circumferential surface of the curved segment between the outer circumferential guiding convexes and the outer circumferential stoppers which are adjacent each other in the circumferential direction does not overlap a segment of the inner circumferential surface of the curved segment between the inner circumferential guiding convexes and the inner circumferential stoppers which are adjacent each other, in the circumferential direction of the cage.