| 摘要 |
In the present invention, a second member is caused to rotate with respect to a first member in a smoother manner than has been conventional. The present invention has a worm (50) and a driving side worm wheel (40) and following side worm wheel (60) that are disposed sandwiching the worm (50). Of the worm (50), both ends in the axial direction are supported by a bearing, and in the direction approximately perpendicular to the axial center of the worm (50), the teeth of the driving side worm wheel (40) and following side worm wheel (60) make contact at both sides in the direction approximately perpendicular to the axial center with backlash, and are thereby supported. When the second member is rotated relative to the first member, the worm (50) rotates relative to the driving side worm wheel (40), the following side worm wheel (60) rotates by means of the rotary force of the worm (50), and the rotary force of the following side worm wheel (60) is regenerated by the worm (50). As a result, whirling vibration of the worm (50) is suppressed, and relative rotation occurs smoothly. |
