Lubrication Film Generation with Limited Lubricant Supply and Its Tuned Oil Replenishment in a Cylinder-on-Disc Contact

Abstract

Limited lubricant supply (LLS) with tuned dosage is an emerging approach to reduce friction and energy consumption. However, LLS can cause severe starvation when the oil supply is insufficient. Therefore, how to effectively replenish oil to the lubricated contact in LLS operation is very important. Using a custom-made optical slider bearing test rig, this work experimentally revealed some characteristics of LLS lubrication in a cylinder-on-disc contact, and proposed two wettability gradient patterns, namely stripe wettability and interlaced wettability, to regulate the lubricant supply to improve the lubricating properties of LLS. The effect of these two wettability patterns was evaluated experimentally according to the lubricating film thickness. The interferograms of the bearing contact under LLS show that the two patterns can augment the oil replenishment through unidirectional lubricant transport by the unbalanced interfacial force via the wettability gradient. Moreover, the interlaced wettability pattern is more effective due to the discontinuous distribution of lubricant from its hydrophilic/hydrophobic region intervals and the transfer of the hydrophobic film to the hydrophilic regions.