Improving the load capacity of journal bearings with chevron textures on the shaft surface

Abstract

The manufacturing of texture patterns on the surfaces of lubricated bearings proved to be an interesting way of improving the tribological behavior in such systems. Depending on the adopted texture geometry, one can achieve significant reductions in friction or an improvement of the load-carrying capacity. In the case of journal bearings, the adoption of textures in the static surface of the contact (bearing casing) usually reduces the friction coefficient with the cost of increasing rotor eccentricity (an indication of a lower load capacity). In this work, we investigate the effects of texturing the rotating surface of the journal bearing’s lubricated contact. In this case, by adopting a chevron texture pattern, one can improve the bearing load-carrying capacity with the cost of increasing the bearing friction (opposite effect). The hydrodynamic lubrication is modeled by the Reynolds equation considering mass-conserving cavitation, whose solution is obtained using a moving multigrid algorithm due to the moving nature of the textures on the shaft. The results show that the improvement in load-carrying capacity is caused by a localized pumping effect of the lubricant towards the centerline of the bearing. In addition, the optimization of the texture geometry for different operating conditions leads to a general design guideline for such textures in journal bearings.