Abstract
The advantages of smoother speed ratio change, simpler mechanisms andlighter weight, etc., are the main reasons for the rubber V-beltcontinuously variable transmission (CVT) being popular used in scooters.However, the low efficiency problem of the CVT system at the normaloperating condition has not been significantly improved. As the demands ofthe environmental protection become stringent, improving the efficiency ofthe CVT system would be the spotlight of the new development in the nearfuture. The main parameters that influence the efficiency of the CVT system hasbeen found in this thesis, based on the dynamic behaviors of the system,which is used to classifies the power analyses and simulation. Asemi-empirical formula for estimating the system efficiency are obtained byconsidering the experimental and simulation results. While some parametersare altered in the new design, the trend and range of system efficiency canbe predicted by using the proposed semi-empirical formula. Therefore it is avery important tool for developing the new model of CVT systems. The radius of curvature of the belt on pulleys, axial forces and beltcharacteristics are found to be the main parameters that affect theefficiency of the CVT system from the theoretical analysis andsemi-empirical formula. More attention should be paid to these parameterswhen designing a high performance CVT. The proposed semi-empirical formulahas been proved to be a very helpful tool for predicting the dynamicbehaviors of a newly developed system.