Research On Vibration Performance And Fatigue Life For Bearing Cage Of Locomotive Traction Motor

Cylindrical roller bearing is widely used in locomotive traction motor due to its strong radial bearing capacity and good high-speed operation performance.With the increase of locomotive speed,extended routing and wide area operation,the fatigue fracture problem of traction motor bearing retainer appears many times,which leads to the failure of the whole bearing in advance,causing a major hidden danger to the safe operation of the locomotive.To solve this problem,this paper takes the cylindrical roller bearing at the drive end of traction motor of HXD₂ electric locomotive as the research object,studies the vibration characteristics,modal characteristics and fatigue life of cage,and carries out experimental verification.The research results can provide refere-nce and basis for the optimization design and research of traction motor bearing of loco-motive.The main research work of this paper is as follows:（1）The multi rigid body dynamic simulation model of the bearing is established by using ADAMS software.The rationality of the contact model is verified according to the roller contact load and cage centroid trajectory.The effects of different motor condi-tions,bearing radial clearance and cage pocket clearance on cage slip rate and accele-ration level of mass center vibration are analyzed.The results show that the slipping and centroid vibration of cage increase,which is easy to cause premature fracture and failure of the cage under the highest speed condition;appropriate reduction of bearing radial clearance or increase of cage pocket clearance is beneficial to reduce abnormal vibration of cage and improve its motion stability.（2）The free modal analysis of the cage is carried out by using the finite element method,the effect of crack on the natural frequency of the cage is analyzed,the trave-ling wave frequency of the cage is calculated,and the flexible body of the cage is gene-rated.The rigid-flexible coupling dynamics simulation model of the bearing is establi-shed by using ADAMS software,and the vibration frequency characteristics of the cage are analyzed.The results show that the main frequency of the sixth order vibration of the cage is close to the frequency of the back traveling wave corresponding to the natu-ral frequency of the seventh order under the rated speed condition.（3）Based on the rigid-flexible coupling dynamics simulation model of the bearing,the effects of different motor conditions,radial clearance of the bearing and the cleara-nce of the cage pocket on the strength of the cage are analyzed.Using the nominal stress method,the fatigue life of the cage is predicted by considering the factors affecting fati-gue life,such as stress concentration,surface quality,structure size and average stress.The results show that the fatigue life of the cage will be greatly shortened if the motor is operated at the highest speed for a long time.In the optimal design of bearings,it is sug-gested to choose radial clearance of about 0.15 mm and pocket clearance of about 0.6mm,which can prolong the service life of the cage.（4）The test bed for measuring rotating speed of cage of cylindrical roller bearing is developed,and the rotating speed and slip rate of NU203 cylindrical roller bearing cage are measured.By comparing the test results with the simulation results,it is verified that the dynamic simulation method of cylindrical roller bearing based on ADAMS software is feasible and effective.73 pictures,13 tables,100 references.