Technical Viability of Using Differential Gears Mechanism as a Variable Speed Drive

Abstract

Variable speed drive technology has advanced dramatically in the last 10 years with the advent of new power devices and magnetic materials. This has given rise to substantial confusion by users and specifiers of variable speed drive equipment. Add to that the difficulty in evaluating efficiency, torque and power. And this make the subject of drive selection becomes a daunting task indeed. There is no single type of drive system which is perfect for all applications. Therefore the purchaser must choose the most appropriate system for the job to be done. In the automobile differential gear drive which consists of two side gears and two pinion gears, the function of the differential pinions gears is to compensate the decrease in the speed of the output of one of the differential side gear by increasing the speed of the other differential side gear by the same amount. The fact above was used to constructs a variable speed drive using the differential gear mechanism. In the proposed design the speed of one of the side gear will be reduced using an electromagnetic brake in order to increase the speed of the other differential side gear, to which an output shaft is connected. The attainable torque, power and efficiencies were calculated using Microsoft Excel package. The results of this research proved that the technical viability of using differential gears mechanism as a variable speed drive is a viable. And suitable for applications where the extended speed range was required, as in the work shop machines.