Pulley, ball bearing and belt transmitting device

摘要

Means are provided for effectively restricting or preventing occurrence of abnormal noise under cold ambient. The means are durable, cost effective and also keep the function of a pulley.A ball bearing 2 of a single row type includes an outer ring 2a and balls 2c. The outer ring 2a and each ball 2c are contacted with each other at two points. An oil groove 5 is formed at a position adjacent to the contact positions P and Q on the raceway surface between the raceway surface 3a of the outer ring and the balls 2c. The ball bearing 2 is fitted within or made integral with the inner diameter of a pulley body 1 having a peripheral surface 1e to be contacted with a belt.