| 摘要 |
PROBLEM TO BE SOLVED: To provide a ball bearing for turbocharger which has low rotational resistance, low vibration and noise level, and excellent durability. SOLUTION: The diameter d13a of each ball 13a constituting the ball bearing 22 is regulated to be 1.8-3.0 mm, and the contact area of a rolling surface of each ball 13a and an outer ring raceway 9 and an inner ring raceway 11a is reduced respectively. In addition, the radius of curvature r11a of the sectional shape of the inner ring raceway 11a is regulated to be 53-60% of the diameter d13a of each ball 13a to ensure a space between the rolling surface and the raceway surface in the vicinity of a contact part of the rolling surface of each ball 13a with the inner ring race 11a. As a result, the rotational resistance is reduced, and the area of biting foreign matter such as small dust and wear powder is reduced to achieve the above good effects. |
