Research On Mixed Lubrication Of Ball Bearing With Rough Surface

The macro performance of rolling bearing, such as bearing capacity, vibration noise, strength, reliability and life, is not only influenced by its structure and material, but also by the microcosmic characteristics of lubricate and surface quality. Nowadays, the influence of lubrication is often neglected in the calculation of bearing dynamics and design, or the influence of shear stress is calculated by empirical formula. However, There is a great deviation between theoretical results and the actual value, which leads to the difficulties to accurately describe the lubricate performance of contact surface, especially facing aviation application.Therefore, research on mixed lubrication of ball bearing with rough surface is carried out in this paper. The lubrication and friction characteristics of the contact surface with different roughness textures are analyzed which will lay a certain theoretical and practical foundation for reducing friction and wear, improving the reliability and life of bearing.Fristly, the roller and outer/inner ring of deep groove ball bearing are simplified. The thermal elastohydrodynamic lubricate model of bearing is established. The numerical solution method of the elastohydrodynamic lubrication(EHL), multigrid method, is studied. Then, the multigrid method is used to numerically solve the long-elliptical thermal elastohydrodynamic lubrication.Apartly, the influence of load, speed and ellipticity on bearing lubrication are analyzed and discussed.Furthmore, a new method to solve the problem of mixed lubrication is found to instead of multigrid method. The mixed lubrication of bearings is solved numerically by using the method of progressive mesh densification(PMD), and the effects of the roughness parameters including amplitude, wavelength and texture are analyzed. It also put emphasis on the effects of environmental viscosity, radial load and rotating speed on the lubrication of bearing.Finally, the experiments of measuring friction coefficient in mixed lubrication are conducted. The surface roughness and topography are measured by using the 3D White light interferometer. The ball-disc friction experiments are conducted by using friction and wear tester. The friction coefficients under different loads, speeds and amplitudes of roughness are measured. Furthermore, the effects of speed and load on friction coefficient are analyzed. The experimental results are compared with theoretical results. It turns out high reliabity between these results.