Hybrid Ceramic Rolling Bearings For High-speed Motors Study Of Kinetic Characteristics

The rolling bearing-rotor system,as the main component of a high-speed industrial motor,determines the mechanical performance and operational safety of the motor.In the daily work of motors,rolling bearings are found to be damaged at an early stage,which seriously affects the efficiency of experimental work.In order to solve the above problems,the transient dynamic behaviour of the rolling bearing-rotor system needs to be studied,and the dynamic characteristics of the rolling bearing,as the core component of the rotor system,determine the dynamic performance of the rolling bearing-rotor system.Therefore,the study and analysis of the dynamic characteristics of rolling bearings is beneficial to guide the design research and daily use of rolling bearing-rotor systems in high-speed industrial motors.At present,the process of modelling rolling bearing-rotor system simplifies the rolling bearing and cannot truly reflect its dynamic characteristics.Therefore,this paper builds a multi-body dynamics model of rolling bearing-rotor system and studies the changes of dynamic characteristics of the rolling bearing.Firstly,the Hertz contact between the rolling element and the inner and outer rings is analysed,the relative position changes of the rolling bearing before and after loading and the mechanical model under high speed conditions are derived,and the changes in its thermal expansion are considered.The dynamics models of the rolling bearing-rotor system,the rolling element and the inner ring are established respectively to provide a theoretical basis for the establishment of the dynamics simulation model of the rolling bearing-rotor system.Secondly,the three-dimensional models of the rolling bearing and rotor were established by using Solid Works software,and the finite element method was used to discretize the mesh to form the finite element model.Based on the contact theory of rolling bearing,the theoretical solution and finite element solution are calculated for the contact stress of rolling bearing,and the contact stress of rolling bearing under different rolling body materials are compared;the modal and vibration analysis of rotor is carried out,and the accuracy of rotor modal analysis is verified by modal experiment.Based on the dynamics model of rolling bearing-rotor system and the theory of spatial multi-body system,a multibody dynamics simulation model of rolling bearing-rotor system is established by COMSOL software.Then,the influence of different working conditions on the changes of rolling bearing dynamic characteristics is obtained through dynamic simulation,focusing on the influence of operating speed,rotor unevenness,rolling bearing preload,thermal expansion of inner and outer rings and starting acceleration,and the gap between rolling body and inner and outer rings,contact force and the change law of rolling body and cage mass centre trajectory are analysed one by one.Finally,a rolling bearing-rotor system test bench was designed and built to conduct vibration tests on the system.The vibration response characteristics of the high-speed rolling bearing-rotor system were investigated at different speeds,different balance amounts and in the presence of coupling faults,and the accuracy of the simulation results of the rolling bearing-rotor system multi-body dynamics model was verified.The multi-body dynamics simulation model of the rolling bearing-rotor system established in this paper provides a useful reference for the study of the dynamics of rolling bearings.