| 摘要 |
<p>PROBLEM TO BE SOLVED: To provide a ball screw having a support nut that can move in the same direction as that of a ball nut in which the outer peripheral surface of a screw shaft is provided with projection screws threadably engaged with the support nut.SOLUTION: This invention relates to a ball screw in which a ball nut 5 is movably and threadably engaged with a screw shaft 3. The outer peripheral surface of the screw shaft 3 is provided with projection screws 11, 13 separate from ball screw grooves 7 where balls installed at the ball nut 5 roll. Leads of the projection screws 11, 13 are set to be smaller than leads of the ball screw grooves 7. The projection screws 11, 13 are cut at a segment where the ball screw groove 7 and the projection screws 11, 13 are crossed to each other. Both sides of the ball nut 5 are provided with support nuts 17 that are movably and threadably engaged with the projection screws 11, 13. There are two projection screws and each of the projection screws 11, 13 is cut at an axial symmetrical position.</p> |
