BALL BEARING FOR TURBO-CHARGER

摘要

PROBLEM TO BE SOLVED: To provide a ball bearing for a turbo-charger having little rotation resistance (rotating torque) and emitting little heat. SOLUTION: The radius of curvature r9a of the cross-sectional shape of an outer ring raceway 9a is 52 to 54% of the diameter d13 of each ball 13. The radius of curvature r11a of the cross-sectional shape of an inner ring raceway 11a is 53 to 55% of the diameter d13 of each ball 13. The angle α of contact of each ball 13 is 8 to 20 deg.. As a result, the area of contact at the portion of contact between the rolling surface of each ball 13, the outer ring raceway 9a and the inner ring raceway 11a is reduced and a slip which occurs at the portion of contact is reduced.