High Speed Ball Bearing-Rotor System Comparative Study Of Nonlinear Dynamics

With the production and scientific and technological development, rotary machines are towards higher-speed, stronger in load-capacity, lighter in weight and more automated. These machines are playing important roles in various engineering fields. In order to ensure the safe operation of the rotor system supported by rolling bearings, it is necessary to study non-linear dynamic characteristics of systems. Although the hybrid ceramic ball bearings gradually replace the steel ball bearings used in high-speed, the compare of nonlinear dynamics between the two is necessary, and it can provide theoretical guidance for immature design of the hybrid ceramic ball bearings. The main object of this dissertation is to study a horizontal rigid rotor supported by angular contact ball bearings, analyze the nonlinear dynamics of system in case of different internal clearances, calculate and simulate its complex nonlinear dynamic behaviors.First, the dissertation discussed the structural characteristics and the main parameters of ball bearings, carried out analysis of the kinematics, load distribution, stiffness analysis and model, and selected the appropriate numerical calculation methods.Secondly, the radial internal clearance of ball bearings is selected as the main parameters for research, compare of hybrid ceramic ball bearings and steel ball bearings is studied under balanced force or unbalanced force. In some typical parameter regions the bifurcation diagrams, the shaft centerline orbit, the phase portrait, the Poincare maps are acquired by numerical integration methods. The results of a parametric study have resulted in the observation that the systems may undergo period doubling bifurcation, quasi-periodic and chaotic motions, and different materials for the rolling bodies can occur different non-linear response characteristics. It is not simply apply the steel ball bearing design theory to design and manufacture of hybrid ceramic ball bearings.Through analysis of calculating results, some important conclusions are obtained, which may be useful for the ceramic balls rotor system.