Electronic system of rubber belt electro-mechanical continuously variable transmission for motorcycle applications

Abstract

This paper deals with the design of electronic system for changing the transmission ratio of a rubber belt electro-mechanical continuously variable transmission (CVT) for motorcycle applications. In this CVT, the rubber belt is used as a medium to transfer both the speed and torque from the input pulley to the output pulley based on contact friction force existed between the belt and both pulley surfaces. Each pulley set consists of one fixed and one sliding pulley sheaves. The axial position of the input sliding pulley sheave is detected using a two channel incremental rotary encoder and controlled by an electro-mechanical shifter system utilizing DC motor, actuator gear set and cam mechanism. The sliding sheave of the output pulley is axially pushed by contra spring to provide sufficient belt compression for preventing belt slip. The CVT ratio is changed by varying the input and output belt-pulley contact radii. It can be done by controlling the axial position of sliding input pulley sheave, the angular speeds of input and output pulleys are sensed using one channel incremental rotary encoders. By knowing these two speed values, the CVT ratio can be computed. The microcontroller system of Arduino is programmed to detect and control the axial position of the input sliding pulley sheave to regulate the CVT ratio. The experimental results show that the electronic system can perform the CVT ratio changes adequately.