Failure Mechanism Analysis And Finite Element Simulation Of Wind Turbine Bearing

The rapid development of wind power industry promotes the development of wind power special bearing industry.In recent years,China has made great progress in the design and manufacture of wind power special bearing.However,there is still a big gap with the world’s advanced level in the aspects of bearing life,bearing capacity and reliability.In this paper,the main shaft bearing of a megawatt wind turbine is taken as the research object.After the first 3MW wind turbine bearing in Yumen Changma wind farm in Gansu Province was used for only a few years,part of the cage on the blade side of the main shaft bearing broke.Serious friction and wear occurred between cage and inner ring,cage and rolling body,inner ring and rolling body,cage and bearing connecting accessories,which eventually led to the fan unable to operate normally.In this experiment,the macroscopical failure morphology was observed by the ultra depth of field microscope,the micro morphology and microstructure were observed by the scanning electron microscope,the chemical composition was determined by the atomnic emission spectrometer,and the hardness of the carburized layer was measured by the microhardness tester.Based on the ANSYS finite element analysis platform,the contact stress of the established main bearing cage is analyzed,and the main stress area of the bearing is analyzed.The stress distribution of the inner and outer raceway of the bearing under the rated wind speed is solved,and the dangerous loading position of the roller contacting the.cage is determined.According to the analysis of experimental results,the failure mechanism of wind turbine bearing is determined finally:1.The poor sealing of the main bearing chamber of the fan results in the abrasion of the sealing ring lip or the leakage of lubricating grease,which leads to the insufficient or insufficient lubrication of the main bearing raceway,the formation of oil-free dry friction heating state and the high temperature rise of the bearing,and the occurrence of soft layer and rolling deformation on the bearing roller body and raceway bearing surface,which further develops into contact fatigue peeling off.In addition,the lip of the seal ring of the bearing chamber is worn and the supporting spring is broken and broken,and the interference with the moving parts of the bearing also causes damage to the bearing parts.Therefore,the main reason for the abnormal damage and failure of fl-3506/2000 main bearing is the poor sealing of fan main bearing chamber.2.The maintenance operation failed to adjust the filling cycle and amount of lubricating grease in time according to the sealing state of the main bearing chamber of the fan,and replenish lubricating grease in time to ensure that the main bearing raceway has sufficient lubricating grease and normal lubricating effect,so the on-site maintenance is the secondary cause of bearing damage and abnormal failure.3.F1-3506/2000 main bearing,as a large-scale heavy load bearing with integral steel cage and guided by inner ring structure,is used in megawatt wind power condition.Its structural characteristics determine its reliability is relatively poor.When the bearing parts are damaged or damaged,and the rolling is blocked,its inner ring is easily driven by the torsion of blade end,which accelerates the failure process of bearing parts。Therefore,the structural form of fl-3506/2000 main bearing will also lead to accelerated damage of bearing components.