Peer-reviewed: Effect of EHL contact conditions on the behavior of traction fluids

The traction response of fluids over a wide range of EHL contact conditions was studied. A series of model experiments were performed using a mini traction machine on three high-viscosity polybutene samples. Significant reductions in traction occurred when the contact transitions from the rigid piezo-viscous toward the rigid iso-viscous region. Similar results were found for two other high-viscosity fluids of different molecular structure and lower traction properties. The results showed that it is important to understand the relationship between fluid performance and the contact conditions at which the data is obtained. It would be dangerous to assume that any changes in transaction observed from small scale bench tests will be observed at the same points in a full-scale infinitely variable transmission system.