| As the core driving component of high-speed machining technology,the motorized spindle can maintain high precision,high efficiency and high reliability operation during the high-speed operation of the machine tool.Therefore,for high-speed machining centers,the performance of the motorized spindle determines its processing quality.However,the vibration of the motonized spindle can inevitably occur during its operation,which directly affects the processing accuracy of the parts.At the same time,the noise generated by the vibration of the motorized spindle can pollute the processing environment to a certain extent.The application of ceramic materials in the main rotating parts of motorized spindle,instead of traditional metal rotating parts,can improve the ultimate speed and stiffness of motorized spindle,and the application of ceramic motorized spindle is a trend of high-speed machining technology.However,as a non-metallic material,ceramics have diffebrent thermal,magnetic,electrical and mechanical properties from metal materials.Therefore,the electromagnetic characteristics and the electromagnetic vibration and noise produced by ceramic motorized spindle are different to some extent compared with that of metal motorized spindle.In this thesis,170SD30 ceranic motorized spindle is taken as the mam research object,and the electromagnetic vibration and noise characteristics of ceramic motorized spindle under the condition of power supply by frequency converter are studied.The details are as follows:1.Theoretical analysis of air gap magnetic field of motorized spindle is earnied out.The magnetic field characteristics of the motorized spindle are calculated by electromagnetic theory,and then the electromagnetic force of the motorized spindle with or without static eccentricity is calculated by Maxwell stress tensor method.The influence of eccentricity on the electromagnetic force is obtained by comparative analysis.At the same time,the electromagnetic characteristics of the 170SD30 ceramic motorized spindle are obtained by theoretical model analysis.2.Electromagnetic field of motorized spindle was analyzed by finite element method.The two-dimensional finite element model of the motorized spindle is established by using Ansys Maxwell finite element software.The distribution of magnetic field and the variation of radial electromagnetic force acting on the stator with time under the transient electromagnetic field condition are sunulated and analyzed.By comparing and analyzing the difference of magnetic field force distribution of motorized spindle under different materials,it 1s found that the electromagnetic force of ceramic motorized spindle is smaller than that of metal motorized spindle.The electromagnetic force characteristics of motorized spindle with 0.1mm static eccentricity are investigated,which verifies the correctness of the theoretical model.3.Coupling analysis of vibration and noise generated by electromagnetic field of motorized spindle is conducted.In Ansys Workbench,the modal of spindle stator is analyzed.The finite element model of stator subsystem is established,and the modal of stator subsystem is calculated numerically.The transient electromagnetic force from two-dimensional transient field is applied on the stator tooth surface of the spindle as the harmonic load of the structural harmonic response analysis.The results of the electromagnetic vibration response of the spindle under normal and eccentric conditions are obtained.The noise model is established for the acoustic field coupling analysis of the spindle transient structure,and the variation law of the electromagnetic noise sound pressure of the spindle is obtained.4.Vibration characteristic of motorized spindle is investigated by experimental test.Vibration of motorized spindle is analyzed by means of vibration experiment,and the source of exciting force causing vibration of motorized spindle is identified.The vibration levels of the motorized spindle at different rotational speeds are calculated and compared with the simulation result of the noise sound pressure levels of the electromagnetic noise of the motorized spindle obtained by the coupling analysis to verify the accuracy of the coupling analysis method. |
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