| 摘要 |
<p>A ball screw device capable of reducing the size of a nut member (2), simplifying a circulation structure for balls (3), performing smoothly endless circulation of the balls (3) between the nut member (2) and a screw shaft (1), and minimizing rotating torque variation while a screw shaft (1) is rotated relative to the nut member (2). A ball circulation groove (21) corresponding to all the periphery of the screw shaft (1) is formed in the inner peripheral surface of the nut member (2). The ball circulation groove (21) comprises a load rolling groove (22) facing the ball rolling groove (10) in the screw shaft (1) and a ball returning groove (23) connecting one end to the other end of the load rolling groove (22). The ball returning groove (23) is directly formed in the inner peripheral surface of the nut member (2) continuously with the load rolling groove (22), and the shape of the cross section of the ball returning groove (23) in a direction perpendicular to the advancing direction of the balls is formed in such a Gothic arch shape that the balls (2) can be brought into contact with the ball returning groove at two points.</p> |
