Effect of spherical-convex surface texture on tribological performance of water-lubricated bearing

In this reported study, 12 types of spherical convex surface textured thermoplastic polyurethanes (TPU) samples were produced using 3D printing technology to determine if these surfaces could improve the performance and service life of water-lubricated bearings. The wear process of the TPU/QSn7-0.2 friction pairs was analyzed using a specially designed testing apparatus under water-lubricated conditions. As part of the analysis, the friction coefficient, surface topographies, grinding marks and the wear mass from the worn specimens were examined. The analysis results showed that the spherical convex texture effectively improved the tribological properties of the TPU material. The friction coefficients between the friction pair were directly related to the test rotation speed and applied loads. Abrasive wear and adhesive wear were found to be the major wear mechanisms of the non-texture specimen, while the spherical-convex textures appeared to facilitate the removal of friction pair debris from the surfaces, reduced the adhesion between the friction pairs and strengthened the wedge effect and cavitation effects of the water flow. Compared to the non-texture samples, the 1/3 spherical texture samples with an S = 38% exhibited improved tribological properties, and the friction coefficient of these samples was decreased by 64.47% at 0.7 MPa and 250 rpm. These results provide an experimental foundation for the textured design and optimization of the water-lubricated TPU bearing surface. •The spherical convex texture effectively improved the tribological performance of TPU water-lubricated bearing material.•A wedge gap formed between the spherical convex texture and a QSn7-0.2 disc was helpful in forming a local high-pressure water-film.•Cavitation effects produced between adjacent convex bodies during the wear process improved the lubrication performance.