On Transient EHL of a Skew Roller Subjected to a Load Impact in Rolling Bearings

Based on the non-steady state operating condition in machine elements, numerical analysis of a transient elastohydrodynamic lubrication (EHL) finite line contact between a skewed roller and an outer race in cylindrical roller bearings was carried out, and a complete numerical solution of skewed roller pairs EHL under the transient condition was obtained. The effects of the load impact, together with the skewing angle impulses on the lubricating performance of skew roller pairs were discussed. Results show that, different from the steady state, the transient effect of the skew roller lubrication is mainly governed by the skew angle impulse, and the load impact. The film dimple is generated during the load impact, or the skewing angle impulse due to the normal approach velocity of the film. Compared to that of the ideal roller, the minimum film thickness decreases due to the roller skew when the transient load happens. Variation in the skewing angle leads to contrary distribution of the film thickness at the two half parts of the roller. Meanwhile, it can decrease the minimum film thickness and be harmful to the lubrication compared to the steady state. Consequently, the transient effect in the process of lubrication of skew roller pairs should not be neglected.