Design of a Self-Actuating, Traction Drive System for High-Speed Ratios

Traction drive systems offer unique advantages over geared systems. They will typically run quieter and they can be designed to eliminate all backlash. Furthermore, rolling elements are easy to manufacture and the rolling motion will produce very efficient power transmission. In this paper the authors describe a two-stage, self-actuating, traction drive system that has been fabricated to produce a speed ratio of 50:1. Given specific values for coefficients of friction, the geometry of each stage of the device must be designed to ensure self-actuation. In addition, dimensions of the drive rollers and output rings for the two stages must be selected to ensure that one stage does not cause the other stage to overrun.