| Rolling bearings are widely used as a key basic component of machinery,in addition to the bearing manufacturing process,their structural parameters also have a very important influence on the contact stress and deformation between the rolling element and the raceway,raceway wear and fatigue life.This paper takes the deep groove ball bearing(6202)as the research object,from the perspective of structural optimization,and analyzes the influence of the groove curvature radius on the fatigue wear of the bearing raceway,and improves the fatigue life of the bearing by optimizing the structural parameters such as the raceway groove curvature radius and rolling element diameter.Hertz contact theory is the basis for analyzing bearing contact stress and deformation.In this paper,the load distribution of deep groove ball bearing is analyzed based on Hertz theory,and the calculation model of friction moment and fatigue life of the bearing is established,which lays a theoretical foundation for the subsequent bearing structure optimization.The influence of groove curvature radius deviation on bearing raceway wear is studied by a single factor test method,and the wear cycle and raceway wear mechanism are discussed.From the perspective of improving bearing load capacity and fatigue life,reducing friction moment and reducing bearing wear,taking the maximum dynamic load,the maximum static load and the minimum friction moment of the bearing as the objective function by using genetic algorithm,the linear weighting method is used to transform it into a single-target multi-constraint,and the five main structural parameters of bearing rolling element diameter,average bearing diameter,number of rolling elements,inner ring raceway groove curvature radius and outer ring raceway groove curvature radius are optimized.The stress and deformation distribution between the inner and outer raceways of the deep groove ball bearing before and after optimization are analyzed by finite element comparison.It is verified that the fatigue life,reliability and wear resistance of the deep groove ball bearing are improved after optimization.The test shows that before 800 h,the bearing wear is mainly in the running-in phase and the wear speed is faster;and after 800 h,the bearing enters the stable wear phase,the wear speed is slowed,the wear rate is small and the wear is more stable.There are mainly fatigue wear,abrasive wear and adhesive wear between the roller body and the inner and outer raceways,which are mainly manifested as many and dense furrow like grooves,producing flake debris and small and deep pits,as well as mutual transfer of matrix materials between the contact surfaces.The larger the curvature radius of the bearing groove is,the smaller the compactness of the bearing rolling body and the raceway is,the smaller the contact area between the rolling body and the raceway is,and the greater the stress and deformation of the contact area are under the same load.After optimization,the diameter of the rolling element of the bearing is increased by about 34%,and the radius coefficient of the curvature of the raceway groove is significantly lower than that before optimization and both tend to 0.515.The maximum contact stress and deformation of the optimized bearing rolling element and the inner ring raceway were reduced by about 24.56% and 24.39%,there is also a certain change in the maximum radial deformation of the bearing,the maximum frictional stress between the rolling element and the raceway,and the maximum slippage of the rolling element.There are alternating cyclic stress changes between the rolling elements of the bearing and the raceway,which is the main cause of fatigue wear failure of rolling bearings.The results show that the stress and deformation between the inner and outer raceways of the 6202 deep groove ball bearing are obviously reduced after the optimization,which achieves the purpose of bearing optimization and improves the fatigue life and reliability of the bearing. |
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