| 摘要 |
PROBLEM TO BE SOLVED: To provide a ball screw which can adjust a preload without using a spacer.SOLUTION: In this double-nut type ball screw, a protrusion 2 extending to an axial direction is formed at one nut 20A, and a recess 5 which can accommodate the protrusion 2 is formed at the other nut 20B at abutment sides of the two nuts 20A, 20A. Pressing faces 3A, 3B, 4A and 4B are formed at four points of the recess 5, and female screws 6A, 6b, 7A and 7B are formed at four points of an external peripheral face of the other nut 20B at positions opposing the pressing faces 3A, 3B, 4A and 4B. Four pieces of press screws 8A, 8B, 9A and 9B are screwed into the female screws 6A, 6b, 7A and 7B, the pressing faces 3A, 3B, 4A and 4B which are formed at the protrusion 2 by fitting the press screws 8A, 8B, 9A and 9B therein are pressed, preloads are thereby imparted thereto by a force which displaces phases of the two nuts 20A, 20B around their axes, and positions in which the preload are imparted are held.SELECTED DRAWING: Figure 1 |
