Tribological Properties of Rock Bit Journal Bearings for Journal with Nanosecond Laser Surface Texture

Abstract

One of the urgent problems that has yet to be addressed in the field of drilling engineering is how to further improve the working performance of rock bit journal bearings (RBJBs) and prolong their service life under complicated conditions of low speed, heavy load, and high temperature. Generally, reasonable surface texture parameters serve as an effective means for enhancing the lubrication and antiwear performance of the sliding surface under harsh lubrication conditions. This study combines the geometric similarity with Sommerfeld similarity and designs an RBJBs scaling experiment; then, experimental studies are performed using an improved journal bearing test bench. The effects of nanosecond laser-textured shape, geometric parameters, and angle factors on the tribological properties of RBJBs are discussed. The results indicate that cylindrical, elliptical, and chevron textures with appropriate parameters can significantly reduce the wear and improve the lubrication performance of RBJBs under the simulated test conditions.

Keywords:

• RBJBs
• surface texture
• nanosecond laser processing
• friction and wear

Additional information

Funding

We would like to acknowledge the National Key R&D Program of China (No. 2018YFC0310201-03), National Nature Science Foundation of China (NSFC) (No. 51775463), and Chengdu International Cooperation Project (No. 2019-GH02-00055-HZ) for their financial supports.