Study On Vibration Characteristics Of Roller System Of Roller Mill

The roller mill is the main equipment for flour processing.The roller mill system which plays a decisive role in the quality of flour processing and the performance of equipment is the core component of the mill.And its working stability is very important.With the development of large-scale pulverizers,the requirements of the accuracy for the main components of the pulverizer are getting higher and higher,and the requirements of the stability for the pulverizer are becoming more and more stringent.At present,there are few researches on the vibration of grinding rolls.Based on the principle of rolling mills,this paper studies the grinding rolls of pulverizers,clarifies the vibration mechanism,and explores the causes of vibration.The main research contents of this paper are as follows:1.According to the current measurement data of flour mills and laboratories and related vibration parameters,the vibration impact parameters of grinding rollers are divided into grinding roller process indexes,material physical characteristics indexes and grinding roller system supporting performance.Determining the imbalance of the grinding roll,the mutual disturbance between the roll materials and the support stiffness are the key research objects of the theory and experiment in this paper.Through the study of dynamic characteristics,the parameter relationship among the speed,imbalance and amplitude is obtained.2.According to the structure of the grinding roller and the characteristics of the supporting regulating mechanism,the adjustment mechanism and mechanical characteristics of the clutch rolling mechanism,the fine tuning mechanism and the overload protection mechanism were analyzed,and the supporting regulating mode of the slow roller was defined.The bottom is hinged with the eccentric wheel,and the upper part is fine-tuning rod and spring elastic support.The result showed that the self-locking condition of the mill is that the Angle between the center of mass and the line where the center of mass is located and the horizontal direction is 45°.At this time,the stability of the clutch rolling mechanism is higher when the roller is subjected to external load.3.Based on Newton's law of motion,the dynamic characteristics of the grinding roll were studied,and the dynamic model of the fast and slow rolls was obtained,and the dynamic model of the slow roll was solved by the perturbation method.Through numerical analysis,it was found that the eccentricity of the grinding roll varies with the mass of the grinding roll.the amplitude increases linearly.With the increase of the speed,the amplitude of the grinding roll experiences a trend of first increasing and then decreasing.It was calculated that the theoretical amplitude of the fast roll at steady state is maintained at around 0.008 mm,and the amplitude of the slow roll and the rolling pitch are fine-tuned.When the support stiffness of the tie rod is related,the amplitude-frequency characteristic curves of different nonlinear stiffness after dedimensionalization are obtained.4.The static analysis of the fine adjustment mechanism of rolling distance was carried out by ANSYS software.The weak points of the parts were obtained.It was found that the deformation of the parts has little influence on the supporting performance of the slow roller system,but it will reduce the precision of the grinding roller adjusting mechanism.Starting from the modal analysis of the assembly body of the grinding roller,harmonic response and random vibration analysis were carried out.The response of the running state with time under the simple harmonic load caused by the unbalance of the roller itself,and the random vibration of the roller under the unsteady load from the roller pressure was obtained.5.By testing and researching the vibration parameters of the grinding roller system of the pulverizer,it is obtained that the empty load amplitude of the fast roller is mainly maintained at 0.006 mm and 0.009 mm.Compared with the theoretical calculation results,the error is small.The slow roller vibrates everywhere up and down.The parameters are different.The overall vibration form is not linear reciprocating vibration,but the shimmy vibration with the eccentric wheel at the bottom of the grinding roller bearing seat as the axis.The shimmy vibration is more obvious under load,and the shimmy form of the slow roller is proposed,and the resonance simulation is carried out.The analysis results are consistent,which provides a basis for the research on vibration suppression of the mill.