Skidding Dynamic Model Of Rolling Element Bearing And Features Of Vibration And Noise

Rolling element bearings are key basic elements, which affect the machines’performance and life directly. Skidding of rolling element bearing does not onlyaccelerate the bearing’s wear, destroy rotary precision and lead to vibration and noiseabnormally, but also cause smearing, elevate the temperature of lubricant and evenbreak the lubricant film, so skidding will seriously affect the performance and life ofrolling element bearing. Because of the complexity of contact mechanism and internalmotion of rolling element bearing, especially when considering the skidding mechanismunder variation of load and speed of the rolling element, acoustic-vibration calculationmethods coupling bearing with the pedestal can not be solved very well. And thus itbecomes a barrier for the research and development of rolling element bearings withhigh precision, low noise and long life. Currently, the topics with respct to skiddingdynamic model and algorithm of rolling element bearing, as well as how skiddinginfluences the rolling element bearing’s life, vibration and noise have become keycommon scientific problems which needs to be solved urgently. So, the studies aboutskidding mechanism of rolling element bearing, dynamic model and acoustic-vibrationcalculation methods have great theoretical significance and practical engineering value.This paper mainly focuses on: the skidding causes of rolling element, dynamicmodel to investigate skidding of rolling element at entry into the loaded zone, dynamicmodel to investigate whole skidding of rolling element bearing during angularacceleration process，the effect of skidding on the vibration characteristic of rollingelement bearing, acoustic-vibration model for bearing noise and the effects of skiddingon the noise characteristics. The main tasks of this paper are listed as follows:①Based on the analysis of skidding causes of the rolling element and their effectson bearing’s performance, the skidding dynamic model of the rolling element enteringthe loaded zone was built, with taking non-linear contact, variable friction coefficient,clearance, nip angle and other non-linear factors into consideration. Nip skiddingbehavior while rolling element entering the loaded zone was studied, and how theskidding of the rolling element was affected by the bearing’s load and speed was alsoinvestigated;②The complete contact model of the rolling element bearing and the interactionmodel between rolling elements and cage were established, and then the motion differential equations of the inner race, the rolling elements and the cage were derivedrespectively. The complete skidding dynamic model of the rolling element bearingduring angular acceleration was built. It is validated by comparison with the resultsfrom Harris’s model and experiment. The skidding characteristics of rolling elementbearing during angular acceleration process and how they can be affected by the bearingload and the angular acceleration of inner race were studied;③The skidding of the rolling element was taken as the excitation of the bearing’svibration. Taking account time-varying stiffness, clearance, skidding of rolling elementsand other non-linear factors, the non-linear contact forces and sliding friction forces dueto skidding were derived. Then, the vibration model of the rolling element bearing wasestablished. The vibration response of the rolling element bearing was obtained, and thevibration features of the bearing under skidding when the rolling elements entering theloaded zone were studied;④Dynamic model, finite element model and boundary element model werecoupled together to establish the pedestal’s acoustic-vibration model. The vibrationresponse of the outer race was obtained based on the vibration model ofbearing-pedestal system, which was the excitation source of the vibration and noise ofthe pedestal. The finite element model of the pedestal was built, and full method wasused to perform transient dynamic analysis to obtain vibration response of the pedestal.The boundary element model of the pedestal was built, where the pedestal’s surfacevibration response was applied as boundary condition. Direct boundary element methodwas used to solve boundary integral formula in Helmholtz equation, which enables theanalysis of the pedestal’s acoustic characteristics. Validity of the model wasdemonstrated by comparison with experiment results. The noise features of the bearingunder skidding while rolling elements was entering the loaded zone were studied, whichcould provide theoretical basis for the resuction of the vibration and noise.