| 摘要 |
<p>A planetary differential screw-type rotational motion/linear motion converter uses both a planetary screw mechanism and a differential screw principle and converts rotational motion to linear motion with accuracy higher than conventionally achievable. The converter has a screw shaft (20), planetary screw rollers (36) meshing with the screw shaft on its periphery, and a roller nut (24) surrounding the screw shaft and the planetary screw rollers and meshing with the planetary screw rollers. The screw shaft (20) and each planetary screw roller (36) are meshed through the screws threaded in the directions opposite to each other, and each planetary screw roller (36) and the roller nut (24) are meshed through the screws threaded in the same direction. The screws have the same pitch. The effective screw diameters and the number of the threads of the screw shaft, planetary screw rollers, and roller nut are related such that none of them is displaced in a thrust direction even when the screw shaft (20) or the roller nut (24) is rotated. On the other hand, the number of the threads of the screw shaft or the roller nut is increased or reduced, so that when either of them is rotated, the planetary screw rollers rotate relative to the screw shaft and the roller nut without sliding.</p> |
