A crown cage is applied to a ball bearing for high-speed rotation for a dental hand piece or the like. The cage has a cylinder formed by injection molding of a thermoplastic resin, and pockets for holding balls that are formed at a predetermined circumferential pitch in the cylinder. A first recess including a gate cutting trace at the time of molding, and second recesses for correcting rotational imbalance of the cylinder caused by the first recess, are formed in the cylinder. The recesses have almost the same shape, and are arranged at a predetermined circumferential pitch.
CROSS REFERENCE TO RELATED APPLICATION
This application claims priority benefits under 35 U.S.C. .sctn. 119 to Japanese Patent Application Serial No. 7-31017 and Japanese Patent Application Serial No. 8-017770.
This application is also a continuation-in-part (CIP) patent application of U.S. application Ser. No. 08/603,160, filed Feb. 20, 1996, and now abandoned.
Both of these documents are incorporated herein by reference.
Priority Data
Feb 20, 1995 [JP] 7-031017 Feb 02, 1996 [JP] 8-017770
A ball bearing cage fitted in a pulley main body having peripheral surface to be contacted by a belt. The pulley bearing includes a raceway surface and grease. The cage has pockets for receiving balls which are circumferentially disposed with unequal pitch such that when some of the vibrating balls impart channeling to the grease on the raceway surface, the other balls ride on the grease on the raceway surface. This suppresses or prevents the occurrence of cold peculiar sound.
A ball bearing which includes a cage which defines recesses for receiving balls in a single row. The cage is in the form of a ring obtained by casting or machining and is intended to be interposed between an inner ring and an outer ring of the bearing. The cage includes recesses of a first group each having an opening for positioning a ball located on a first side of the cage, while recesses of a second group each have an opening for positioning a ball located on a second side of the cage, opposite the first side.
