Rolling Traction in Isoviscous-Rigid, Piezoviscous-Rigid, and Elastohydrodynamic Lubrication Regimes at Line Contact

This paper deals with rolling traction in isoviscous-rigid (IVR), piezoviscous-rigid (PVR), and elastohydrodynamic lubrication (EHL) regimes at line contact. First, a measuring method of rolling traction using the two-disk machine supported by ball bearings was explained. Then, the rolling traction in the IVR, PVR, and EHL regimes at line contact was measured. The measured results showed that as load P increases, the time average rolling traction F-R AVG in the IVR and PVR regimes increases, while that in the EHL regime does not significantly increase. The measured F-R AVG was lower than the rolling traction F-R TED/CPA under the isothermal condition calculated by using the commercial software TED/CPA. To establish the rolling traction expression, a rolling traction expression under the isothermal condition F-R iso was first derived by means of curve fitting the calculated F-R TED/CPA. Then, a rolling traction expression (which takes into account the thermal effects of the inlet shear heating) F-R thermal was derived by multiplying the thermal correction factor C-t to the expression F-R iso. Finally, it was shown that the proposed expression F-R thermal is effective for estimating the rolling traction in the IVR, PVR, and EHL regimes at line contact.