Coupled Driven Variable Transmission Unit

Abstract

This presents a coupled driven variable transmission unit that can vary its gear ratio 1/60 and 1/300. Conventional variable transmission units such as V-belt and roller CVTs are not appropriate for robot joints because they cut off power transmission while varying gear ratios or are simply too large. Variable transmission units that use two motors are also developed for robot fingers. However, one of the motors in the units does not contribute output, which is a dead weight during operation. The proposed variable transmission unit uses two motors for output based on coupled drive of them. The rotation directions of the two motors determine the gear ratio and the rotation direction of the output shaft. This paper describes installation of the developed variable transmission unit using worm gears. Experimental results validate the variable transmission unit, which is effective especially for power saving.