Performance Evaluation of Ball CVT and Comparison with Half Toroidal CVT

This study aims at finding an analytical model of ball continuously variable transmission (B-CVT) behavior and performance, based on the existing model of the half-toroidal traction drive. The geometrical and kinematical aspects of this model have been found. Then, force-moment equilibrium equations have been applied for a B-CVT. The contact behavior has been modeled using the isothermal elastohydrodynamic lubrication (EHL) theory, and spin and relative slip losses have been estimated for this CVT. Finally, the overall efficiencies of the B-CVT have been analyzed and compared with the halftoroidal traction drive. This study results have shown that B-CVT has higher torque efficiency and lower speed efficiency in comparison with half-toroidal CVT. Also, it has shown that the adjustment of axial forces in B-CVT leads to higher efficiency in lower input torques.