A Study On Surface Damage And Diagnosis Method Of Rolling Bearing

In recent years,in order to meet the development needs of China’s economic modernization,the running speed of high-speed trains has been continuously improved,which increased the probability of contact fatigue failure of high-speed railway bearings.A large number of studies show that contact fatigue failure was the main manifestation of the failure of each ring component in high-speed rail bearing.Nowadays,there were some problems such as the lag of fault discrimination and low sensitivity in the way of monitoring the change of axle temperature commonly used for bearing fault diagnosis on high-speed trains,However,vibration signals have the advantages of high sensitivity and real-time feedback in monitoring mechanical faults,but there was still a lack of systematic research on fatigue damage of high-speed railway bearings based on vibration signals.In this paper,ABAQUS simulation software was used to simulate the running of the bearing,the stress distribution of each component was analyzed,the damage model of the bearing component was established,and the fatigue damage and diagnosis method of the rolling bearing were studied.Through the simulation operation analysis of the bearing,it was found that:The vulnerable part of the bearing was the local area where the outer end edge of the tapered roller contacts the inner ring,where the stress was the largest;The stress conditions of each component of the bearing were different during operation,and the stress order was rolling element>inner ring>cage>outer ring;The eccentric load would occur during the running of the bearing;Precast pitting defects did not change the motion state of the bearing,but would affect its stress distribution,especially the cage;The fatigue life of the bearing could be briefly simulated and evaluated based on the maximum contact stress analysis;The damage types of bearing ring parts could be divided into two types,surface stress concentration type and sub-surface stress concentration type,which was consistent with the rolling contact fatigue damage type of ring samples.Based on the vibration signal analysis,the fatigue damage process of the annular specimen was systematically studied,and the quantitative relationship between the wear amount of the annular specimen and the time-domain index value was established.A method for predicting the cycle number of the annular specimen based on the initial time-domain index value was proposed.The failure mechanism of contact fatigue between annular samples was analyzed,and then the failure mechanism of contact fatigue between annular components of bearings was explained.Based on the vibration signal analysis,the fault diagnosis method of bearing fatigue failure at the initial stage was systematically studied.The results show that:the combination of various time domain parameters can make a more accurate judgment on whether the bearing components have faults;Combined with the analysis of energy percentage and energy entropy index,the severity of the fault could be evaluated.According to the data fitting,it could be known that the average energy entropy and the diameter of pitting fault area basically meet the following quantitative relationship:y=0.65-0.09167x-0.708x~2;Pitting defects will aggravate the bearing vibration and change the running track of the bearing parts,which was consistent with the simulation results;Three improved fault feature extraction methods were proposed,all of which can accurately diagnose the initial fault of bearing fatigue failure.The research results provide support for fault diagnosis of high-speed railway bearing under driving conditions in the future.