Fatigue Strength Analysis Of Permanent Magnet Synchronous Spindle Rotor

Permanent magnet synchronous electric spindle is a key component in numerical control machining machine tools and plays an important role in processing and production.The advantages of compact structure,high power density and good stability make permanent magnet synchronous electric spindle widely used.Permanent magnet synchronous electric spindle directly influences the reliability and processing precision of numerical control machine tool,with the development of modern manufacturing technology,it is very important to analyze the mechanical strength and fatigue life of permanent magnet synchronous electric spindle.Rotor eccentricity is the main cause of radial magnetic pull and unbalanced mass tension of permanent magnet synchronous electric spindle.The asymmetric distribution of the rotor will cause distortion of the air-gap magnetic field,and the electromagnetic force generated by the high-frequency transformation of the magnetic field will act on the rotor,which will have an effect on the mechanical strength and fatigue life of the rotor.In this paper,the permanent magnet synchronous electric spindle is analyzed in detail for the above reasons,and the following work is accomplished:The theoretical calculation and experimental simulation of permanent magnet and stator loaded magnetic field in permanent magnet synchronous electric spindle are carried out,which are in good agreement with each other.The influence of stator grooving on the air gap magnetic field in permanent magnet synchronous electric spindle is obtained by theoretical derivation.The internal magnetic field of permanent magnet synchronous electric spindle is simulated by using Ansoft software.The theoretical results are compared with the results of finite element simulation,and its accuracy is verified.Two different eccentricity forms,static eccentricity and dynamic eccentricity,are derived theoretically and simulated by finite element method,and the variation law of air-gap magnetic field under different eccentricity forms is analyzed.The radial magnetic pull and unbalanced mass tension of the rotor under different eccentricity forms are calculated,and the mechanical strength of the rotor is checked by Ansys Workbench software.The fatigue life of rotor is predicted by Ncode Designlife software.In this paper an embedded analysis of the principle and regularity of permanent magnet synchronous electric spindle internal magnetic field is carried out,the results of theoretical calculation and finite element simulation results are compared which in good agreement,and prove the accuracy of the theoretical calculation method.The radial magnetic pull and unbalanced mass tension generated by rotor eccentricity have been solved,the mechanical strength of rotor with different eccentricity forms and different eccentricity value is checked,and its strength to meet the requirement.The fatigue life of rotor under the action of high frequency radial magnetic pull and unbalanced mass tension is predicted which meet the requirements of application.