Dynamics Analysis Of Rolling Element Bearing With Local Defects In Outer Ring By FEM

Rolling bearing is one of the indispensable components in rotating machinery,its operation state directly affects the performance,service life and machining accuracy of mechanical equipment.Under the action of the cyclic load,the rolling bearing will exhibit different forms of fatigue spalling or fatigue pitting failure in the inner and outer raceways and rolling elements in the bearing region under high stress conditions.The formation of fatigue failure can cause the entire rolling bearing to fail and the dynamic response of the bearing to change.Therefore,the study of the dynamic characteristics of the local defect rolling bearing is significantly important for the fault diagnosis and identification of the rolling bearing.The research content of this thesis includes:(1)The finite element dynamics modeling of rolling bearing is studied.Taking the rolling bearing as the research object,the finite element dynamic analysis model of the outer raceways surface line spalling defect bearing and the non-defective bearing is established by using ABAQUS/Explicit.Considering the influence factors such as load,rotation speed,contact and friction,the dynamic responses of the defect bearing and without defect bearing on the surface of the outer ring are investigated.The equivalent stress of the defect bearing and without defect bearing is simulated and analyzed.The variation trend of the inner coupling point in vertical direction under the combined action of radial load and rotational speed is obtained,the validity of the simulation model is verified.(2)The stress of the rolling element rolling over the local defect is investigated to estimate the size of the defect.The dynamic characteristics of rolling bearings in different defect widths,depths,then the evolution of defect corners into arc are analyzed.The vibration responses of the outer raceways and rolling element joints are analyzed.The equivalent stress between the rolling elements and the outer raceway and its variation when the rolling elements enters and rolls out the defect were analyzed,and the size of the rectangular defect is estimated according to the moment of the equivalent stress when the rolling element enters and rolls out the defect.(3)The multi-event process of the contact force between rolling elements and inner and outer raceway is study.The law of contact force of rolling bearings in increase defect widths and depths is analyzed.Comparing the contact force of the rolling elements of the local defect bearing and the without defect bearing with the inner and outer rings in the horizontal and vertical directions,it can be seen that the change trend of the contact force of the local defect bearing and the without defect bearing is similar,and a multi-event process is shown when rolling element rolls over the local defect of outer.