The combined effect of contact interface size and spin on lubricated traction in rolling-sliding point contacts

Traction in lubricated rolling and sliding contacts plays an important role in the performance of several machine elements. Many of such elements are subject to spin motion, which can affect their performance. Recent studies have also highlighted the effects of the contact scale on the traction behaviour. Nevertheless, their combined effect was not investigated to date. The present study, therefore, analyses the effect of both on the traction in heavily-loaded lubricated contacts. To this end, a novel semi-analytical traction prediction model was developed considering spin motion. The results show that increasing the contact size and/or spinning speed leads to a reduction in traction coefficient and contact efficiency due to thermal effects. These conclusions have important practical applications designing machine elements.