A new approach to the design of a speed-torque-controlled rubber V-belt variator

Abstract

This paper presents a new model for a torque-speed-sensing rubber V-belt variator. The actuators are of the centrifugal roller kind on the driver side and a helical torque cam plus a compression-torsion spring on the driven side. The equations permit designing the actuator geometry in order to keep the transmissible torque as close as possible to the torque request in the whole operative field. Moreover, a procedure is suggested for the most proper design of an automatic variator of this kind. It permits choosing the required variogram of the transmission, i.e. the matching between the engine and the transmission, and designing the actuators: roller mass, housing shape, contact plate angle for the centrifugal roller actuator, and helical guide slope for the torque cam actuator. Furthermore, the degree of engine transmission matching can be calculated at part load for fixed actuators. Extensive experimental tests were carried out on a proper bench test to validate the procedure.