| 摘要 |
The present invention has: a first worm gear 29 that is rotatably borne on a gear case 11 and a bearing member 16, the first worm gear being coupled to an output shaft 24 of a motor 13; and a helical gear that is geared with the first worm gear 29. In the gear case 11 and the first worm gear 16, an engagement recessed portion 42 and an engagement protrusive portion 43 configured to engage with each other are provided. At the engagement protrusive portion 43 of the bearing member 16, a first press-in fixing protrusive portion 44 configured to be pressed-in and fixed to an engagement recessed portion 42 of the gear case 11 is provided. As a result, according to the present invention, a rotational center O1of the first worm gear 29 is positioned at the normal rotational center. |
