Study of a New Transmission System for Electric Scooters

Electric scooters are the most popular form of transport for old and disabled people in Taiwan and its popularity is fast increasing as people are living longer and longer. The main components of an electric scooter includes battery, motor, motor driver, and a transmission system, whose characteristics determine the overall energy efficiency. The commonly used transmission system of an electric scooter consists of a compound gear train (or a simple gear train) and a bevel gear differential, the quality of the former of which significantly influences the efficiency and noise level. In this paper, a new transmission system for use in an electric scooter is proposed. The finite element method was applied to evaluate the stress level experienced by the gears in the compound gear train. A test rig was also set up to compare the performance of the proposed transmission system with an existing commercial product. The new design was shown to produce better performance characteristics in terms of efficiency and noise level than the commercial product and has since been successfully manufactured and is currently being sold worldwide.