Dynamic Characteristics Analysis of Rotor-Bearing System Considering Bearing Clearance and Hybrid Eccentricity

PurposeIn order to analyze the effects of rotor hybrid eccentricity and bearing clearance on the internal excitation force and dynamic characteristics of the rotor bearing system of a permanent magnet motorized spindle, a nonlinear dynamic and lumped parameter model of the rotor bearing system is developed in this paper.MethodsFirstly, the model is solved based on the variable-step Runge-Kutta method. Secondly, the effect of internal parameter variations on the timefrequency characteristics of the system is analyzed by the Fourier transform. Finally, based on the bifurcation trajectory of the system speed and the Poincare map, the dynamic characteristics evolution of the rotor-bearing system in the full speed range is analyzed.ResultsThe results show that the variation of rotor mixing eccentricity and bearing clearance leads to a complex coupling of nonlinear excitation forces within the system, which in turn causes the system to exhibit rich dynamic behavior.ConclusionChanges in the initial static eccentricity of the rotor will lead to changes in the frequency characteristics of the unbalanced magnetic pull, and increasing the eccentricity of the rotor mass will increase the amplitude of the system response, which is more likely to lead to resonance due to changes in the coupling state of the excitation forces within the system due to changes in bearing clearance. When the rotor eccentricity and bearing clearance are controlled in a small range, the system has better stability in the high-speed range

Automated summary

This study develops a nonlinear dynamic and lumped parameter model to analyze the effects of rotor hybrid eccentricity and bearing clearance on the internal excitation force and dynamic characteristics of the rotor bearing system of a permanent magnet motorized spindle. The results show that the variation of rotor mixing eccentricity and bearing clearance leads to a complex coupling of nonlinear excitation forces within the system, which in turn causes the system to exhibit rich dynamic behavior. When the rotor eccentricity and bearing clearance are controlled in a small range, the system has better stability in the high-speed range.