Dynamic And Static Rigidity Characteristic Analysis And Comprehensive Optimization Method Of Lathe Spindle

The dynamic and static rigidity of machine tools directly affects the machining accuracy and efficiency and is an important index to measure the performance of machine tools.As the core part of the machine tool,the spindle has always been an important research direction to improve its structural stiffness.By means of structure optimization,the machining accuracy and efficiency of the machine can be effectively improved by improving its static and static rigidity.This paper takes CK6140 machine tool as the research object,through modeling and analysis,studies the main influencing factors and rules of the dynamic and static rigidity of the spindle structure,and then explores a method to comprehensively improve the static and dynamic rigidity of the spindle.The main research contents are as follows:The first chapter,the paper analyzes the machine tool structure optimization research,the stiffness optimization research and neural network was applied to optimize the mechanism research status at home and abroad,summarizes the shortcomings in the course of research and application at present,put forward the "lathe spindle dynamic and static stiffness characteristics analysis and comprehensive optimization method" research topic,and introduces the research train of thought and main content.The second chapter,in order to study the influence rule of structural parameters on the spindle's static rigidity,a 3d model of machine tool spindle was established.Finite element software was used to study the influence rule of design parameters on the sensitive deformation direction of the spindle,and the structural parameters significantly affecting the spindle's static rigidity were selected.Orthogonal experimental method was used to analyze the significant degree of influence of structural parameters on the static rigidity of spindle and correlation analysis was carried out.The influence of sensitive design parameters on the static rigidity of spindle is studied under single variable and multiple variable conditions.The third chapter,in order to study the influence law of structural parameter changes on the dynamic stiffness of the spindle,the relationship between the dynamic stiffness of the spindle increasing with the increase of natural frequency was analyzed by taking the partial derivative of the dynamic stiffness.The first six natural frequencies are obtained through modal analysis of the spindle.The first natural frequency of the spindle is taken as the measurement standard.The structural parameters that significantly affect the dynamic stiffness of the spindle are selected by analyzing and comparing the influence rules of structural parameter changes on the first natural frequency.The influence of the sensitive design parameters on the dynamic stiffness of the spindle is studied in the case of single variable and multiple variables.The fourth chapter,in order to characterize the nonlinear relationship between structure parameters and the spindle static stiffness,combining genetic algorithm and BP neural network mapping model is set up,before the spindle structure parameters of study selected as input values of neural network training samples,choose according to stiffness defined type representation of dynamic and static stiffness of the performance parameters of the maximum deformation,displacement amplitude as the training sample output indicators,to make the model accuracy is higher,the output value between each other,respectively set up parameters on the mapping model;At the same time,in order to ensure that the strength and natural frequency of the optimized spindle meet the design standards and the quality of the spindle remains unchanged,the mapping models of structural parameters and maximum stress,first-order natural frequency and mass are respectively established.Finally,a total of 5parameter pair mapping models were obtained,which were used for the establishment of subsequent structural optimization models.The fifth chapter,in order to achieve the final optimization goal of improving the static and dynamic stiffness of the spindle,the spindle structure parameters is taken as design variables.The performance parameter mapping model of the spindle obtained above is used to represent the nonlinear relationship contained in the constraints,and a structural optimization mathematical model is established.The structure parameters of machine tool spindle are optimized to obtain the optimal horizontal combination of structure parameters.The optimized machine tool spindle model was established,and the static performance of the machine tool spindle was analyzed by using finite element analysis,and the performance parameters of the obtained machine tool spindle were compared with the corresponding data before optimization.The results show that the static rigidity of the spindle increases by 14.09% and the dynamic rigidity increases by 16.04%,both of which have been significantly improved,and the performance of the spindle is optimized.The sixth chapter,the research work is summarized and the future research is prospected.