A full toroidal traction drive IVT for automotive volume production

摘要

With the successful demonstration of its Sport Utility Vehicle (SUV) infinitely variable transmission (IVT) in a 5.4 litre Ford Expedition vehicle Torotrak achieved a key milestone in its technology development. The level of functionality achieved in the prototype vehicles has been commended by vehicle and transmission manufacturers. The technical focus has since switched to the optimisation of the transmission for volume production. This has resulted in a number of new challenges for Engineers and Tribologists. This paper describes the research and development work undertaken to deliver the full toroidal traction drive variator at a cost, weight and package optimised for volume production. The outcome of this work is the downsizing of the variator to provide a transmission that is competitive in package size, weight and cost with the latest 6-speed stepped automatic transmission designs, whilst delivering excellent vehicle performance and fuel economy gains in excess of 10%.