| 摘要 |
<p>PROBLEM TO BE SOLVED: To realize a reduced noise in a small size of ball bearing using balls less than 3 mm of diameter. SOLUTION: This ball bearing is composed by holding plural balls 3 between an inner ring 1 and an outer ring 2 through a holder 4, and the diameter Dw of the ball 3 is less than 3 mm. And at least one of the inner gear 1, the outer gear 2, and the balls 3 is formed of a steel which satisfies IP/Dw<=2, when the total sum of the particle diameter of a nonmetal inclusion whose particle diameter exceeds 5μm existing per its detected area 1000 mm2 is made IP. In particular, it is favorable that at least one of the inner ring 1, the outer ring 2, and the balls 3 is a consumption electrode type vacuum remelted steel, or a consumption electrode type vacuum remelted steel obtained by using an electrode of an electroslug remelted steel.</p> |
