| 摘要 |
PROBLEM TO BE SOLVED: To make the deflections of ball screws smaller and consequently prevent the service lives of the ball screws from lowering and the losses in their power transmissions from developing and realize the precise movement of a movable plate, by a method wherein a supporting plate for regulating the positions of a plurality of ball screws is provided at a movable plate, and the end part of each ball screw is rotatably mounted to the supporting plate. SOLUTION: A supporting plate 6 is mounted through bearings 8 to the end parts of a plurality of ball screws 3. The supporting plate 6 is mounted through supporting materials 7 to a movable plate 2. On each shaft 3b of the ball screw 3, a pulley 5 is provided. A belt 4 is spanned between the pulleys 5. As a result, even a driving force is transmitted through the belt 4 to the ball screw 3, the bending moment of the ball screw 3 becomes smaller, since the end of the ball screw 3 is supported by the supporting plate 6. In addition, since the behaviors normal to the axis directions of a plurality of the ball screws are coincident with each other by restricting a plurality of the ball screws 3 with one sheet of the supporting plate 6, the movement of the movable plate becomes precise. Further, by separating the engagement between the supporting materials 7 and the supporting plate 6, the supporting plate 6 is easily taken off.
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