| 摘要 |
PURPOSE:To dispense with a ball cover having so far been used, by setting up a moving body, holding a ball group on an outer circumferential part of a worm free of rotation, in an axial direction of the worm free of reciprocating motion. CONSTITUTION:A cylindrical moving body 8 is being fitted in an outer circumferential part of a worm 6 with some play, while a ball group 4 to be fitted in a ball track 5 of the worm 6 is held on this moving body 8 free of rotation, and the moving body 8 is constituted so as to perform its reciprocating motion with movement of the ball group 4. The ball group 4 of this moving body 8 is set up threadlike with the same lead as the ball track 5 of the worm 6. Retention of the ball group 4 of this moving body 8 is no matter what constitution may be if the ball group 4 is not separated and free of rotation. |
