| 摘要 |
PROBLEM TO BE SOLVED: To realize a structure capable of preventing impression from being formed at an outer ring side large-diameter raceways 6c, 6d or a hub side large-diameter raceways 11c, 11d.SOLUTION: A diameter size Dof each of balls 4c, 4c of a row of large-diameter side balls is made smaller than a diameter size Dof each of balls 4d, 4d of a row of small-diameter side balls. In addition, in the case where a radius of curvature of both outer ring side large-diameter raceways 6c, 6d is R, a radius of curvature of both hub side large-diameter raceways 11c, 11c is R, a radius of curvature of an outer ring side small-diameter raceways 7c, 7d is R, a radius of curvature of a hub side small-diameter raceways 12c, 12d is R, a large-diameter side average curvature ratio fexpressed by (f+f)/2 with a curvature ratio fexpressed by R/Dand a curvature ratio fexpressed by R/Dis made larger than a small-diameter side average curvature ratio fexpressed by (f+f)/2 with a curvature ratio fexpressed by R/Dand a curvature ratio fexpressed by R/D. |
