BEARING DEVICE FOR WHEEL

摘要

[PROBLEMS] To provide a bearing device for a wheel increased in rigidity and increased in the life of bearings by suppressing the occurrence of scratches on balls in an assembling step. [MEANS FOR SOLVING THE PROBLEMS] In this bearing device for the wheel, the pitch circle diameter PCDo of a ball (3) group on the outer side is set larger than the pitch circle diameter PCDi of a ball (3) group on the inner side. The inner peripheral surfaces of corner parts (A) to (D) and the counter parts (E) to (H) at the shoulder parts of rolling surfaces are crushed by a simultaneous grinding with the rolling surfaces by a form grinding wheel to form them in smooth circular arc shapes. A cone-shaped recess (23) is formed at the outer side end part of a hub wheel (21), and the bottom of the recess (23) is positioned at least near the groove bottom of the inner rolling surface of the hub wheel, and the outer side end part of the hub wheel (21) is set to be approximately uniform in wall thickness. As a result, the rigidity of the device can be increased and scratches on balls due to the contact of balls during the assembling and dents in balls by the vibration of balls can be suppressed to improve the acoustic characteristics of the bearings.