Crown-shaped retainer for ball bearing, and ball bearing

A crown type cage for a ball bearing, which is made of resin, comprising:

• an annular main portion;
• a plurality of pillar portions protruding in an axial direction from the main portion at predetermined intervals in a peripheral direction;
• and
• a spherical pocket formed between the adjacent pillar portions and capable of holding a ball, wherein
• each pillar portion has a pair of claw portions of which tip end portions are spaced apart from each other and a connection portion that connects the pair of claw portions, and
• a first surface of the main portion is provided with a first projection portion protruding in the axial direction, wherein
• an inlet having a width shorter than a diameter of the ball and for inserting the ball is provided between the tip end portions of the two adjacent claw portions forming the pocket,
• a radius of curvature of a spherical recessed surface of at least one pocket is greater than a radius of curvature of a rolling surface of the ball,
• an outer diameter of at least one claw portion is smaller than an outer diameter of the main portion,
• a radial width of at least one claw portion is ½ or less of a radial width of the main portion, and
• an axial width from a first surface of the connection portion of at least one pillar portion to the first surface of the main portion is ½ or less of an axial width of the crown type cage for the ball bearing.