Nonlinear Time-Varying Parameter Dynamic Model Of Rolling Bearing And Failure Mechanism Research

In the operation process of rotating machinery,rolling bearings,as an important part,often need to bear high load and dynamic load,which is easy to produce pitting corrosion,peeling,cracks and other faults.The research on bearing fault characteristics is of great significance to timely discover faults and eliminate safety hazards,and is of great significance to production activities.The research on vibration characteristics and fault mechanism based on the dynamic model of rolling bearing fault is the basis for accurate bearing fault diagnosis.In this paper,a 6+N_bDOF nonlinear time-varying parameter bearing dynamic model was established by analyzing the contact deformation,contact stiffness and vibration response of rolling body passing through the defect area of outer ring.The dynamic model simulation and experimental verification provide a theoretical basis for rolling bearing fault diagnosis based on vibration signals.The main research contents are as follows:(1)The fault types,fault causes and vibration mechanism of rolling bearings were introduced.Taking NSK6205 deep groove ball bearing as an object,a 6+N_bDOF rolling bearing dynamic model was established considering the influence of the geometric size of rolling ball on the bearing vibration response,and the motion states of each component in the running process of rolling body were described in detail.(2)Based on 6+N_b DOF dynamic model of rolling bearing,considering the relative geometric relationship between the rolling body and the defect,the time-varying contact deformation function and time-varying stiffness function of the rolling ball passing through the defect area were constructed,and by modifying the direction of contact force.By modifying the direction of contact force,a nonlinear fault contact force model coupled with time-varying contact deformation and time-varying stiffness was proposed,and the characteristics of fault impact vibration response of rolling bearings with different defect sizes were obtained.(3)With roller and bearing inner and outer circle contact deformation depth of the contact surface relative linear velocity on the basis of exploring the influence of the rolling bearing skid dynamics behavior,consider cage rotation Angle,An gle of rotation and revolution of roller,building 7+3N_b degrees of freedom dynamic model of the rolling bearing skid has made a detailed description of rolling bearing skid phenomenon.And under different working conditions to analyze the bearing skid characteristics,explore the bearing skid law.