Stiffness and damping characteristics of lubricated ball bearings considering the surface roughness effect. Part 2: numerical results and application

摘要

A numerical solution for the stiffness and damping characteristics of an isothermal, elastohydrodynamically lubricated point contact is presented considering the surface roughness effect and variation in viscosity with pressure. An attempt has been made to derive empirical formulae for the calculation of stiffness and damping coefficients of lubricated point contacts with a non-linear least-squares curve-fitting technique using different numerically evaluated data, thereby avoiding time-consuming numerical calculations. From this the overall stiffness and damping matrices of the ball bearing are obtained with a proper load distribution. A comparative study on the dynamics of a rotor-bearing system is carried out for a dry contact ball bearing, a lubricated contact ball bearing and a plain journal bearing.