| Permanent magnet synchronous electric spindle has the advantages of high machining accuracy,fast response speed and compact structure.Therefore,permanent magnet synchronous electric spindle is widely used in high-speed CNC machine tools and is an indispensable core equipment in my country’s manufacturing industry.However,the vibration and noise generated by its operation seriously affect the machining accuracy and running stability of CNC machine tools.Therefore,it is of great significance to study the vibration and noise characteristics of permanent magnet synchronous electric spindles.Firstly,this paper uses Maxwell software to establish the finite element model of the permanent magnet synchronous electric spindle,analyzes the air gap magnetic field of the three magnetization methods and conducts simulation calculations.The distribution curves of air gap magnetic density and electromagnetic force density varying with time and position are analyzed.The Fourier transform of the two is performed by Matlab to obtain the harmonic and spectrum analysis diagrams of the air-gap magnetic density and electromagnetic force density.It is found that the main reason affecting the electromagnetic vibration and noise of the electro-spindle is the low-order harmonics of the radial electromagnetic force.Using Solid Works software to build its three-dimensional model and conduct modal analysis on the main components,it is analyzed that the possibility of resonance of the electro-spindle is small,and it can be concluded that the resonance of the electro-spindle can be avoided during operation by optimizing the structural parameters.Secondly,the practicability of the analytical method is verified by the calculation and analysis of the no-load air-gap magnetic field of the permanent magnet synchronous electric spindle with three permanent magnet chamfers based on the equivalent surface current method.By considering the influence of the pole structure on the cogging torque.Using the sparrow optimization algorithm,the multi-objective optimization design of the permanent magnets with triangular chamfering,arc chamfering and rectangular chamfering was carried out,and the harmonic distortion rate of the air-gap magnetic field was optimized to determine the optimal permanent magnet structure parameters.After the optimization of the three permanent magnet structures of the electro-spindle,the result of circular arc chamfering is the best.The circular arc chamfered permanent magnet can effectively suppress the cogging torque and torque ripple when the average torque is basically unchanged.Finally,the vibration simulation analysis of the permanent magnet synchronous electric spindle is carried out in the form of co-simulation of Maxwell and Workbench,and the vibration deformation cloud map and vibration curve are obtained.Then the Ansys Acoustic module is added and the spherical radiation model with a diameter of 2m is imported to analyze and calculate the electric spindle noise sound pressure level.The vibration and noise of the motorized spindle before and after optimization are compared and analyzed.The results show that the circular arc chamfered permanent magnet is the best,which can effectively reduce the vibration and noise of the motorized spindle.It provides a new means to weaken the vibration and noise of the permanent magnet synchronous electric spindle. |
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