Durability of a Compact Dual-Cavity Full-Toroidal IVT Variator

Whilst infinitely variable traction drive transmissions (IVT) have demonstrated the potential to provide significant fuel economy benefits through the optimisation of the vehicle powertrain, greater emphasis is now being placed on reducing the overall package size. Reduced transmission size places increased demands on the ability of the variator elements in the transmission to withstand the heavily loaded contact conditions. Described in this paper are the models and methodology used to size an IVT transmission from a design life view point. In addition, selection of the variator design parameters in order to optimise the durability are outlined. Relevant experimental results from rig tests are presented which demonstrate the ability of a compact IVT design to meet the life targets for a typical SUV vehicle.