To provide a bearing device for driving a wheel which is easy to assemble and disassemble at low cost and contributes to reliability and driveability by suppressing the occurrence of a circumferential backlash at an engaging part.

A hub wheel 1 having a wheel mounting flange 4 at one end, a double row roller bearing 2, and a constant velocity universal joint 3 are detachably unitized with a screw means. In the bearing device for driving a wheel, in which the constant velocity universal joint 3 is connected to the hub wheel 1 via a torque transmission means, the first male screw 21 at the end of an axle 20 and the second male screw 22, whose pitch is designed to be smaller than that of the first male screw 21, at its outer end are each formed. The first nut 26 is tightened with predetermined torque, and the second nut 29 is tightened to the second male screw 22 until it abuts on the first nut 26 so as to effectively prevent loosening of the first nut 26 by frictional force between them and the difference in pitches.

COPYRIGHT: (C)2008,JPO&INPIT