PLANETARY DEVICE FOR CONVERSION BETWEEN ROTARY MOTION AND LINEAR MOTION

摘要

A planetary device for conversion between rotary motion and linear motion, in which the planetary gear mechanism of helical gears and the planetary gear mechanism of screw gears are combined with each other so that a conversion between rotary motion and linear motion can be accurately, stably, and efficiently performed by a rather simple structure. The device comprises a sun shaft (14), planetary shafts (20), and a ring shaft (16) with rotating axes positioned parallel with each other. The sun shaft, the planetary shafts, and the ring shaft comprise a helical sun gear (22), helical planetary gears (28), and a helical ring gear (42) forming a first planetary gear mechanism in cooperation with each other and a screw sun gear (26), screw planetary gears (30), and a screw ring gear (44) forming a second planetary gear mechanism in cooperation with each other. The gear ratio of one of the screw sun gear (26) and the screw ring gear (44) to the screw planetary gears (30) is different from the gear ratios of the helical sun gear (22) and the helical ring gear (42) to the helical planetary gears (28). ® KIPO & WIPO 2008