| 摘要 |
PROBLEM TO BE SOLVED: To provide an inner ring of a bearing device for a wheel by which required strength and rigidity can be maintained and which can be reduced in weight.SOLUTION: A flange 8 of a hub wheel 2 has a thick portion radially outward from its center, and a thin portion formed outside an outer edge of the thick portion. The outer edge of a connection part 21 of the thick portion is connected by a curved contour 22 curved in a direction of the center between adjacent bolt insertion holes 17, 17. The center of the curve of the curved contour 22 (innermost position in the radial direction of the curved contour 22) is within a straight line area 23 formed by connecting the adjacent bolt insertion holes 17, 17 are at a diameter width W (only one portion is shown in Fig.3) of the bolt insertion hole 17. One through-opening 24 formed in an approximate oval shape is formed at each thin portion 18. An inner radial peripheral edge of each through opening 24 is formed along the curved contour 22. |
