To reduce the movement of balls and a retainer, and to reduce the noise level and to enhance the durability of a bearing under a very low-temperature condition by realizing excellent lubrication between a pocket surface of the retainer and the balls, and between the balls and inner and outer ring raceways.
In a ball bearing in which a plurality of balls 3 are disposed between an inner ring 1 and an outer ring 2 in a circumferentially rolling manner via a crown-shaped retainer 10, P.C.D. of the crown-shaped retainer 10 passing through a center of a pocket 15 to retain the balls 3 is smaller than P.C.D. passing through centers of the balls 3, and an outside diameter surface in the sectional shape along the axial direction has a shape not parallel to the axis.
ACHINAMI HIROYA
Yoshiaki Naito
Cui Shu Tetsu