To provide a ball bearing capable of reducing a manufacturing cost, preventing a generation and abrasion originating from a contact resistance by restraining the contact resistance between a ball and a retainer as small, besides checking occurrence of retainer sound.
In a ball bearing 21 equipped with a ball guide type retainer with a protruded fitting part 23c controlling a displacement of bearing diameter direction for the retainer 23 itself by contacting an outside of balls 7 on the edge of outer ring 5 side or inner ring 3 side of a pocket hole 23b accommodating balls 7 as retainer 23 that holds in the interval of balls 7 between inner and outer rings 3, 5, the contact area between retainer 23 and balls 7 is reduced by providing several pieces of fitting protrusion 25 whose top makes point contact with balls 7 as the fitting part 23c of ball guide type retainer.
MORITA YASUSHI
MATSUYAMA NAOKI
