Experimental Study on the Effect of Micro-Texture on EHL Point-Contact Film Thickness Subject to Sliding Conditions

Abstract

Processing texture on contact surfaces can improve the friction performance of mechanical comments. In this research, micro-dimple textures with various parameter were processed on a steel ball’s surface with a picosecond laser. Then, the EHL (elastohydrodynamic lubrication) oil film thickness was measured on an optical ball-on-disc tribometer subjected to pure sliding conditions. The effects of sliding velocity, load, dimple location and dimple depth on the film thickness were analyzed. The results showed that the dimple affected the pressure distribution in the contact area, which in turn changed the distribution of the local film thickness. An increase in the local film thickness occurred between the dimple and outlet of the contact region, while a decrease in the film thickness formed from the dimple to the entrance of the contact area and both sides of the dimple’s edge. Velocity and applied loads affected the film thickness distribution as well. As the sliding velocity increased, the film thickness increasing region enlarged, while the film thickness-decreasing area shrank. The increase in load resulted in a negative effect on the increase in film thickness. This study will provide a reference for point-contact designs with low friction conditions.

Keywords

• laser surface texturing
• EHL
• point contact
• film thickness
• sliding conditions