| 摘要 |
The objects of the present invention is to reduce a backlash at the time of locking of a seat back and to reduce clearance in the thrust direction of a worm so as to prevent generation of an abnormal noise with a simple structure suitable for mass production. Substantially cone-shaped recesses 15 and 16 are provided respectively on both end faces of the worm 4 pivotably attached on a seat cushion, and inside end faces of a pair of holders 13 and 14 to support these two end portions, and at the same time balls 17 are rotatably housed respectively in a pair of spaces formed in the recesses 15 and 16 facing each other to form a pair of bearings 11 and 12 which rotatably support the worm 4. A press means composed of a coil spring 25 and the like which presses the worm 4 to the worm wheel 5 is provided in a locking mechanism. |
