| 摘要 |
PURPOSE:To secure the durability, while restricting a noise made when cold by providing a fine clearance between the inside diameter surface of an outer ring and the outside diameter surface of a holder, or between the outside diameter surface of an inner ring and the inside diameter surface of the holder. CONSTITUTION:When a pulley main body 1 is rotated, an outer ring 2 of a ball bearing 2 is integrally rotated with the pulley main body 1, and a holder 2 facing to the inside diameter surface of the outer ring 2b through a fine clearance S1 is coupled with the outer ring 2b for rotation, and contacts with a ball 2c at the appropriate contact force. The ball 2c thereby receives the revolving directional force from the wall surface 2d5 of a pocket 2d3, and the action in the directions except for the revolving direction is restricted, and the generation of self-excitation due to a stick slide of the ball 2c or the like is prevented so as to restrict a noise made when cold. Furthermore, since the oil film is formed between the inner diameter surface of the outer ring 2b and the outside diameter surface of the holder 2b by the fine clearance S1, abrasion of the holder 2d due to the rotation with the outer ring 2b is eliminated, and the durability of the ball bearing 2 is secured. |
