On Rolling Variators, A study of power transmitting rolling variators when changing speed ratio
Doktorsavhandling, 1986

The introduction of the concept Rolling Variators is proposed for rolling contact continuously variable transmission. A theoretical study of rolling variators when changing the speed ratio during power transmission is presented. Change of the speed ratio in rolling variators is caused by applying a slip (side slip) perpendicular to the rolling direction in the power transmitting contact area between rotating solids. It is theoretically shown that the different forces and the corresponding relative velocities in the contact area become quite independent of each other if the slip is viscous or elastic. the study is continued by investigating their dependence if the slip is plastic and the conditions in the contact area may be described with the Coulomb friction law. Due to the side slip the reduction of the useful frictional force component in the rolling direction is shown to be negligaable for reasonably magnitudes of the side slip velocity. The significance of the theory is verified by experimental investigations.

friction drives

traction drives




speed ratio change

rolling traction trnasmissions

continously variable transmissions

rolling contact drives

transmission ratio change


Göran Brännare

Institutionen för maskinelement





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