Friction and Lubrication in Rolling/Sliding Contacts
The frictional resistance to rolling in dry conditions was extensively investigated by A. Palmgren and D. Tabor, who concluded that slip is negligible and cannot be considered as the mechanism causing rolling friction. Tabor suggested that rolling friction is a manifestation of the energy loss due to hysteresis in the stressed material at the contact zone during the rolling motion under normal load. The quasisteady disk surface temperature and the mean conjection-inlet oil temperature are shown to be strongly influenced by the friction power loss at the contact, but not by the specific make-up of the frictional power loss. The effects of the coated material properties and surface roughness on rolling friction appear to be insignificant for all the performed tests. There are many published empirical formulas for evaluating the coefficient of friction. The formulas were used for evaluating rolling friction, and traction forces in the isothermal, nonlinear, and thermal regimes of elastohydrodynamic lubrication.