Research On Dynamic Characteristics And Fatigue Life Calculation Of Deep Groove Ball Bearings Under High-speed Operating Conditions

Under high-speed working conditions,the stability and safety of the bearing rotor system are greatly reduced.Improving the dynamic performance,life and reliability of high-speed bearings has become one of the key technologies to be solved urgently in the development of high-end equipment technology.This paper takes an aero-engine high-speed ball bearing as the research object,and conducts research work on the key issues in the dynamic simulation analysis and service life calculation of the high-speed bearing.The specific research content and main conclusions are as follows:(1)A digital platform for rapid and effective analysis of multi-body contact dynamics simulation analysis of deep groove ball bearings has been built.The reliability of the digital platform is verified by comparing the error between the theoretical value and the simulated value of the moving speed and relative displacement during the bearing movement.The use of this platform reduces the difficulty of establishing bearing dynamics simulation models and provides a good tool for studying the dynamic characteristics of bearings.(2)Taking an aero-engine gear support bearing as the research object,the working state of the bearing is extracted from the actual environment and converted into the input conditions of the dynamic performance analysis of the bearing to study the dynamic characteristics of the high-speed ball bearing under actual working conditions.The research results show that: under high-speed conditions,the ball has a certain sliding phenomenon;based on the bearing geometry and the axial displacement of the bearing element,the dynamic contact angle of the ball raceway at different times can be calculated.A bearing contact model was established to extract the load sequence of each component of the bearing.The related research results of the dynamic stress in the bearing show that when the outer ring is constrained and the inner ring rotates,the equivalent stress of the inner ring of the bearing is the largest,followed by the equivalent stress of the rolling elements and the outer ring.(3)Using the deep groove ball bearing dynamic simulation analysis platform as a tool,the influence of working conditions and structural parameters on the dynamic characteristics of high-speed ball bearings was explored.The research results show that:the vibration acceleration of the bearing increases greatly with the increase of the speed;due to the influence of the centrifugal force,the load of the bearing outer ring increases with the increase of the speed;the axial displacement and contact angle of the bearing element in the contact zone follow the external load Increase and decrease;bearing load sequence increases as the load increases;as the track curvature coefficient increases,the dynamic stress and axial displacement of the bearing first decrease and then rise;when the track curvature coefficient is 0.535,the dynamic characteristics of the bearing are optimal.In the actual bearing structure design,the selection of the curvature coefficient of the raceway should be selected by comprehensively considering the working conditions and design principles.(4)A local bearing contact model for calculating the contact stress of the ball raceway was established,and the accuracy of the model was verified by the Hertz contact theory.Based on the results of the bearing contact stress field and the related results of the bearing dynamic load spectrum,the bearing fatigue life of high-speed ball bearings is calculated.On this basis,the influence of load and track curvature coefficient on bearing fatigue life is explored.Research shows that under actual conditions,the areas with the smallest fatigue life on the inner and outer raceways of the bearing appear on the edge of the raceway;under the actual conditions,the fatigue life of the inner and outer raceways is about 101 h and 71 h,respectively,and the fatigue life of the ball is about 15 h.The fatigue life of the bearing decreases with the increase of the load,and first increases and then decreases with the increase of the groove curvature coefficient;when the groove curvature coefficient is 0.535,the fatigue life of each component of the bearing is the largest.Studies have shown that the fatigue life of the bearing can be improved by reducing the bearing load and selecting the appropriate track curvature coefficient.