| 主权项 |
1. A screw device comprising:
a screw shaft having a helical rolling-member rolling groove on an outer circumferential surface thereof; a nut having a helical loaded rolling-member rolling groove opposed to the rolling-member rolling groove on an inner circumferential surface thereof; a return path connecting one end and the other end of a helical loaded rolling-member rolling path formed by the rolling-member rolling groove of the screw shaft and the loaded rolling-member rolling groove of the nut; and a plurality of rolling members arranged in the loaded rolling-member rolling path and the return path, wherein when viewed in the axial direction of the nut, a curvature radius change section is provided in the return path, and the curvature radius change section is configured so that a curvature radius of a track centerline of the rolling members in the return path is equal to or larger than a curvature radius of a track centerline of the rolling members in the loaded rolling-member rolling path, and so that the curvature radius of the track centerline of the rolling members in the return path increases gradually or in a stepped manner with increasing distance from the loaded rolling-member rolling path. |
