Analysis Of Static And Dynamic Characteristics Of Magnetoresistance Modulated Motorized Spindle

The development and application of motorized spindles began in the last century,with the development of the manufacturing industry,the R&D and manufacturing technology of the motorized spindle is also steadily improving.At present,high-speed motorized spindles,high-precision motorized spindles,high-power motorized spindles,and Low-speed high-torque motorized spindles have become very popular research directions.The motorized spindle system combines the spindle motor with the rotating shaft to realize "zero transmission",which has the advantages of high power density and high machining accuracy.The high machining accuracy of the motorized spindle is mainly due to good static characteristics,dynamic characteristics and thermal stability.Taking the magnetoresistive modulated motorized spindle as the research object,the selection of its main structural parameters,the advantages and disadvantages of various components were analyzed,and the motor structure was optimized to improve the motor performance.Based on the analysis results,a finite element simulation model was established.The static stiffness simulation was carried out by using the spring instead of the bearing,and the static stiffness of the spindle was obtained.The influence of the main structural parameters of the motorized spindle,span,overhang and bearing preload on the static stiffness of the motorized spindle,was simulated and analyzed.The results show that the static stiffness of motorized spindle decreases with the increase of overhang;The static stiffness of motorized spindle increases with the increase of preload;The static stiffness of motorized spindle increases first and then decreases with the increase of span,and there is an optimal range.The differential equation of motion of the motorized spindle was established.The modal simulation and harmonious response simulation of the spindle system were carried out,the first six natural frequencies and mode shapes of the spindle system were obtained.Then the simulation analysis of the influence of the main structural parameters on the natural frequency was carried out.The analysis results show that the natural frequency of the motorized spindle decreases with the increase of the spindle span;it increases with the increase of the spindle bearing preload;with the increase of the spindle overhang,it first increases and then decreases.The harmonic response of the motorized spindle was simulated to obtain the response of the motorized spindle under the action of periodic external forces.The results show that the vibration is the largest near the first-order natural frequency of the motorized spindle,and the amplitude of the middle part of the motorized spindle is larger than that of the front and rear ends,which is the danger surface.The static stiffness experiment of the motorized spindle system was carried out,and the static stiffness of the motorized spindle was obtained.The modal test of the motorized spindle has obtained the first two order natural frequencies of the motorized spindle system.Comparing the experimental results with the simulation results,it is concluded that the static stiffness of the motorized spindle meets the requirements for use,and the critical speed of the motorized spindle is much greater than the maximum speed,which can avoid the resonance area.The no-load vibration experiment was carried out,and the experimental results show that the vibration amplitude of the motorized spindle is the largest near the first-order natural frequency.