Abstract
Automotive applications of CVT’s using metal belts are continuing to grow. There has been a significant amount of work in the detailed mechanics for these CVT’s.
This CVT technology may be extended into non-automotive areas, which have different size, torque, ratio and speed requirements than automotive applications. The purpose of this paper is to explore the basic performance parameters for the metal belt CVT outside the automotive envelope and to present a design procedure for an initial estimate of torque capacity. This may then be used for preliminary functional feasibility evaluation of metal belt CVT’s in various applications. It can also serve as an instructional tool in mechanical engineering design courses.
The governing equations are first presented for the simplified analysis. Also an optimum pitch radius is derived to maximize torque capacity. A design procedure is listed. This is first applied to a baseline automotive type configuration CVT to illustrate the procedure. Next, the procedure is applied to a non-automotive CVT that could be a diesel engine vehicle or industrial drive characterized by lower engine speeds, higher torque, larger ratio range and greater space available for the transmission.
For the non-automotive application it is shown that optimization for maximum torque capacity vs minimum size for a given belt design can significantly increase torque capacity at overdrive in the range of 25%. The amount of increase depends on the engine speed and an increase in sheave diameters is required.
