Hydrodynamic force and moment in pure rolling lubricated contacts. Part 1: Line contacts

Abstract

Hydrodynamic rolling force and moments in line contact have been studied in detail using isoviscousrigid (IVR) and elastohydrodynamic (EHL) models. Using fully flooded assumptions, curve-fitted relationships are suggested for calculating the IVR and EHL hydrodynamic rolling force per unit length. At high speed and light load, EHL numerical results converge towards IVR results so that a single curve-fitted relationship has been derived for covering the full range of operating conditions with a rapid transition from IVR to EHL regime of lubrication. Results obtained are often close to published results (especially in the IVR regime). The EHL hydrodynamic rolling force per unit length is found to be load independent, while load exponents ranging from 0.01 to 0.37 can be found in the literature. A single relationship for both lubrication regimes (IVR and EHL) is given for deriving a starvation factor function of the ratio between the film thickness at the inlet meniscus and the fully flooded minimum film thickness. Finally, the calculation of the total power loss per unit length has also been conducted by integrating through the film and along the rolling direction the power loss per unit volume (defined as the product shear stress time shear rate). Results obtained are consistent with the calculation of the rolling force per unit length.