Geometric Optimization of Half Toroidal Continuously Variable Transmission Using Intelligent Techniques

The objective of this research is geometrical optimization of Half Toroidal Continuously Variable Transmission (CVT) in order to achieve high power transmission efficiency and low weight. After dynamic analysis of the system, the contact between the disk and the roller is modeled according to elasto-hydrodynamic lubrication principles. Accordingly, a computer model is created with geometric, thermal and kinetic parameters as inputs of the system, to determine the efficiency and the weight of CVT. Results are compared to those obtained from models in other articles to confirm its validity. Geometric parameters are obtained by means of genetic optimization algorithm, while optimization parameters are power transmission efficiency and system weight. It is observed that regardless of weight coefficients assigned to power transmission efficiency and weight, difference between results are negligible. Also, the effect of oil film temperature, speed ratio and rotational speed of input disk on power transmission efficiency for optimized geometry is shown.