Influence of Chief Vein on Tribological Behavior of Vein-Bionic Textured Rolling Element Bearings Under Starved Lubrication

In this research, to investigate the effect of the chief vein (chief trunk of leaf vein) on the friction reduction and wear resistance of vein-bionic textured bearings, four vein-bionic texture patterns inspired by two types of leaves (Clausena lansium, ash) were manufactured on the raceways of the shaft washers of 81107TN cylindrical roller thrust bearings (CRTBs) using a fiber laser marking system. A vertical universal wear test rig equipped with a customized tribopair was employed to record the coefficient of friction (COF) of bearings under starved lubrication, and the generated wear losses of the shaft washers and worn surfaces were characterized. Static finite-element analyses (SFEA) of paths located at different depths in the vertical direction of contact regions for the raceway were conducted to reveal the surface stresses. The results show that all vein-bionic textures exhibit improved tribological properties under starved lubrication, while textures with no chief vein are prone to excellent wear resistance compared to textures with a chief vein. The stress distribution of vein-bionic textures with no chief vein is significantly impacted by various depths: The subsurface stresses reduce with increased depths, but textures with a chief vein have the reverse tendency. A reasonable influence mechanism of the chief vein on the tribological properties of resulting textures is proposed.