Geometrical optimization of half toroidal continuously variable transmission using particle swarm optimization

The objective of this research is geometrical optimization of half toroidal Continuously Variable Transmission ( CVT) in order to achieve high power transmission efficiency. The dynamic analysis of CVT is implemented and contact between the disk and the roller is modeled viaelastohydrodynamic (EHL) lubrication principles. Computer model is created using geometrical, thermal and kinetic parameters to determine the efficiency of CVT. Results are compared by other models to confirm the model validity.Geometrical parameters are obtained by means of Particle Swarm Optimization (PSO) algorithm, while the optimization objective is to maximize the power transmission efficiency. Optimization was conducted over a wide range of selected input parameters that are EHL oil temperature, roller tilting angle and rotational velocity of input disk. Optimization results show that the power transmission efficiency alters with changes of input parameters, while the optimized geometrical parameters are approximately the same. Variations of power transmission efficiency over a wide range of input parameters were calculated for optimized geometry, while the highest value of power transmission efficiency occurs in low value of EHL oil temperatures and input disk rotational velocities. The optimized structure shows average power transmission efficiency equal to 93.4% over a wide range of input parameters.