Development and Assessment of Traction Fluids for Use in Toroidal (IVT) Transmissions

The attributes of a traction fluid are fundamental to the successful operation of a traction drive transmission. The fluid must lubricate and protect the components against wear and corrosion, whilst simultaneously providing high traction to transmit power efficiently.

A selection of commercial and candidate fluids have been assessed with both a bench-test and a novel traction rig. The principal objective has been to achieve a balance between the conflicting requirements of low temperature viscometrics and high temperature traction.

Fluid performance is found to vary according to the rig employed underlining the need to test under prevailing conditions. Data from the traction rig is validated against a variator module.