| 摘要 |
<p>A ball screw device comprises a screw shaft, a nut mounted on the screw shaft, and a number of balls interposed between the screw groove of the screw shaft and the screw groove of the nut. The screw shaft has a ball circulation groove communication-connecting the downstream and upstream sides of the screw groove to return the balls from the downstream to the upstream side for circulation in the screw groove of the screw shaft. The ball circulation groove is formed in a curved shape sinking radially inward in the intermediate region as seen in the ball rolling direction, and in a shape curving radially outward in the regions at the opposite ends. It is arranged that the locus of the center of the ball rolling in the regions at the opposite ends and the locus of the center of the ball rolling in the screw groove of the screw shaft satisfy predetermined conditions concerning the circulation of the ball.</p> |
