The Design and Analysis of an Alternative Traction Drive CVT 2003-01-0970

An attractive new CVT design has been introduced that is a variation of the Kopp variator, currently used in some industrial applications. A prototype of the transmission has been tested and modeled by Southwest Research Institute in efforts to optimize performance over the full range of operating conditions. Analytical predictions and experimental results at steady state are presented that demonstrate higher efficiencies and power capacities with the new design, yielding possible feasibility in a number of vehicle and industrial applications. The traction and power loss prediction is made using models that include evaluation of creep, spin and side slip in the contact patch as well as the influence of asperity contact through the fluid film. Overall, efficiency levels are higher than the Kopp variator and axial load requirements are lower. Additionally, analytical predictions of the transmission performance yield reasonably good agreement with experimental data. These facts along with a compact and lightweight, easy to manufacture design, make the Motion CVT a very reasonable option for possible vehicle and/or industrial applications.