Vibration modelling of nonuniform surface waviness in a lubricated roller bearing

Surface waviness is one important source of vibrations in a roller bearing. When the surface waviness occurs on the surface of the inner or outer race of a roller bearing, a time-varying deflection excitation and a time-varying contact stiffness excitation can be generated due to the changes in the curvature radii of the race with surface waviness at the contact position between the roller and the race of the roller bearing. In this paper, a new dynamic model (TDCE model) considering both the time-varying deflection excitation, the time-varying contact stiffness excitation, and the lubricating oil film is proposed to investigate vibration responses of a lubricated roller bearing with a uniform and a nonuniform surface waviness on its races, which cannot be accurately modelled by the previous time-varying deflection excitation (PTDE) model in the literature. Effects of the number, the maximum amplitude, and the nonuniform distribution of the surface waviness on the contact stiffness between one roller and the race with surface waviness are investigated, as well as the vibration responses of a lubricated roller bearing. Numerical results from the proposed model are compared with those from the PTDE model in the literature, which shows that the proposed TDCE model can provide more accurate impulses generated by the surface waviness on the races of the roller bearing. Moreover, the results show that the proposed method can provide a new vibration modelling method for a lubricated roller bearing with the uniform and nonuniform surface waviness on its races.