| 摘要 |
<p>A device (1) for converting a rotary motion into a linear motion which has three balls (6-1, 6-2, 6-3) held at equiangular positions on the same circle by a ball retainer (8) between a ball rolling surface (4a) formed in an annular fixed plate (4) and a ball pressing surface (3a) formed at the end of a linear motion shaft (3) that can be linearly reciprocated. These balls are retained in place by a coil spring (9). The ball retainer (8) rotates with a rotary input shaft (2). The ball rolling surface (4a) is formed with three undulated cam surfaces along the circumferential direction, so that as the balls (6) held in the ball retainer rotate with the rotary input shaft (2), the balls reciprocate in the direction of the axis line L causing the linear motion shaft (3) to perform a reciprocal linear motion in the direction of the axis line L. Compared with a conversion mechanism comprising a screw and a nut, this conversion device has a small dead band and can easily be reduced in size. <IMAGE></p> |
