Dynamic Characteristics Analysis Of Permanent Magnet Synchronous Spindle Rotor

In the continuous development of modern high-speed manufacturing technology today,higher feed,cutting speed and high precision become important manufacturing factors of two revolutionary,high-speed machining technology has become the world development trend.The electric spindle as the main form of modern high speed machining center,which has long service life.Rotary precision,vibration and noise characteristics of small,low friction power consumption and so on.The main content of this paper is the calculation of critical speed of permanent magnet synchronous motor spindle and rotor unbalance response analysis,calculate PMSM Spindle Dynamic eccentricity of the unbalanced magnetic pull,and then consider the effects of unbalanced magnetic pull on rotor dynamic characteristics.The permanent magnet synchronous electric spindle rotor modal analysis,first calculate the critical speed of the rotor by lumped mass method,discrete model,the calculation of rotor parameters related to the use of VB programming,adding time factor t to set up the transfer matrix,with the help of double step QR solution,calculate the critical speed of rotor drawing the Campbell diagram,considering the gyroscopic effect,and use ANSYS to calculate the critical speed of the shaft system transfer matrix method,the correctness of the two calculation results were compared to verify the results of the simulation.Secondly rotor rotational speed in the first and two order critical speed mode,intuitive analysis of rotor rotational speed in the near critical speed each point of the quality,vibration,as subsequent unbalance response analysis.The final calculation of foundation bearing stiffness influence on the critical speed of the rotor is obtained,permanent magnet synchronous Provide working conditions of electric spindle bearing stiffness.In unbalance response analysis,the quality applied in different positions of eccentric rotor,based on the unbalance response calculation of the critical speed and the rotor response.In the actual working process,there will be errors in the process of machining or assembling the rotor,and when the rotation speed reaches a certain value,the vortex effect will lead to the rotor eccentricity.Because of the eccentricity of permanent magnet synchronous spindle,the density distribution of electromagnetic force is not uniform,and the variation of radial force will produce unbalanced magnetic pull force.The effect of the unbalanced magnetic pull will affect the dynamic characteristics of the rotor,which is equivalent to increasing the mass on the rotor.In this paper,the electromagnetic forces with different eccentricities are calculated and the influence of different unbalanced magnetic pull forces on the critical speed and unbalance response of the rotor is observed.Finally,the stability of rotor bearing system is analyzed with the aid of logarithmic attenuation rate curve.