Skidding Dynamic Model Of Rolling Element Bearing With A Localized Defect In Loaded Zone

Rolling element bearing is one of the most important supporting components ofrotating machinery, which can support the rotor and other components, keep the rotatingaccuracy of the rotor, and reduce the wear and the friction between the rotor and thesupporting components. The wear and spalling are the main failure modes in the rollingelement bearing. According to statistics, more than25%failures of high-speedaero-rolling element bearing are caused by bearing skidding.The normal performancesof the rolling element bearing are greatly affected by the skidding in the bearing, whichmay reduce the accuracy of the bearing, and cause the increases of the temperature ofthe lubricating oil. The oil film fracture and a short lifetime may also be caused by theskidding.In order to reduce the economic losses and casualties caused by the skidding of therolling element bearing, it is important to study the skidding vibration characteristics ofthe bearing. However, since the complex effects of the skidding, the skidding vibrationcharacteristic of the bearing, especially the skidding of the rolling element in the loadedzone and the localized spalling defect zone have not been fully studied due to thenonlinear contact, the clearance, the oil film, the time-varying frictional factors and thecoupling with the cage and so on. Therefore, it is of important theoretical significanceand practical value in engineering to investigate the skidding dynamic model of therolling element bearing and its corresponding analysis.The main failure modes of rolling element bearings are the skidding of the rollingelement in the loaded zone and the localized defect zone. The description of theskidding vibration characteristics of the rolling element and the bearing caused by theskidding of the rolling element in the loaded zone and the localized defect zone have notbeen completely studied. To overcome this problem, a deep-groove ball bearing isstudied in this paper, the skidding vibration characteristics of the bearing consideringthe effects of the oil film and the localized defect is presented. A skidding dynamicmodel of the rolling element bearing is also proposed. The effects of the skidding of therolling element in the loaded zone and the localized defect zone are studied. Somevaluable conclusions are provided. The main contents of the workare as follows:①To overcome the problem of the skidding of the rolling element bearing, theelastic contact deformation and the contact stiffness between the rolling element and the races are calculated according to the Hertzian point contact method, as well as theload distribution of the bearing. The effects of the radial load, the speed of the innerrace, the dynamic viscosity and the viscous pressure coefficient of the lubricating oilfilm on the stiffness and the stiffness of the lubricating oil film.②According to the structural characteristics of the deep-groove ball bearing, askidding dynamic model of the rolling element in the loaded zone considering theeffects of the lubricating oil film is proposed based on the rigid rings assumption, andRunge-Kutta numerical integration method is usedfor solving. The differences betweenthe vibration characteristics of the bearing with and without the effects of the lubricatingoil filmarediscussed. The effects of the radial load and the speed of the inner race arealso studied.③The contact characteristics between the rolling element of the deep-groove ballbearing and the localized defect are described. The contact relationships between therolling element and the localized defect edges are also discussed. A skidding dynamicmodel of the deep-groove ball bearing in the localized defect zone is proposed based onthe time-varying displacement excitation model of the localized defect using thehalf-sine function. The skidding vibration characteristics of the rolling element when therolling element passes over the defect zone are studied.This study expounds the formation mechanism of bearing vibration caused by theskidding of the rolling element in the loaded zone and the localized defect zone usingthedynamic analysis method, as well as the localized spalling defect model base on thetime-varying displacement excitation. Thisworkpresents a new calculation method andsome valuable results for preventing the early bearing failure in bearing industry, as wellas theoretical analysisof the rolling element bearing.