Dynamic Characteristics Analysis Of Feed System Based On Joint Model

With the continuous improvement of the machining accuracy requirements of machine tools in the mechanical manufacturing industry,this puts forward higher requirements for the performance of machining machine tools.Dynamic characteristics are the inherent characteristics of machine tools and the key to study and improve the performance of machine tools.In this paper,the ball screw linear feed system of a type of multi axis ultra precision machining machine tool is studied.According to the relative position relationship between the lead screw and the guide rail in different feed directions of the machine tool,the dynamic characteristics of the ball screw feed system are studied in two forms,the dynamic model is established,and the theoretical correctness of the dynamic model proposed in this paper is verified.This paper studies the dynamic modeling and model verification of single axis ball screw feed system from the following aspects:(1)Based on the contact theory of the joint,the overall stiffness characteristics of the linear feed system are analyzed to effectively reflect the actual stiffness properties of the system.The stiffness characteristics of the joint of each component of the ball screw feed system are analyzed,including the contact characteristics of the internal joint of the bearing,the characteristics of the joint of the ball guide rail and the characteristics of the joint of the lead screw nut,and the stiffness characteristic expression is established,It provides a theoretical basis for the following analysis.(2)Through the model equivalence of the single axis ball screw feed system,combined with the contact stiffness analysis method of the key parts of the single axis ball screw feed system,the dynamic model based on Lagrange differential equation is established and the dynamic characteristics of the single axis feed system are solved;The influence of the feed rate of the feed table of the single axis feed system on the dynamic characteristics of the system is analyzed;The influence of the preload level of the sliding block of the rolling guide rail on the system characteristics is analyzed,and the variation law of the vibration characteristics of each order of the system under different preloads is established.(3)The dynamic model is analyzed in the simulation software,and the overall coupling model and assembly physical model of the system are obtained according to the requirements of the simulation analysis model.The mechanical system multi-body dynamics simulation software ABAQUS is selected to analyze the multi-body dynamics of the single axis feed system selected in this paper.The finite element simulation analysis of the system is carried out from the perspective of system structural mechanics and system vibration analysis,and the vibration natural frequency and vibration mode of the system are obtained for comparative analysis and verification of the theoretical model.(4)The dynamic test experiment of the single axis feed system is carried out,and the experimental results reflect the dynamic modeling solution process based on the contact stiffness of the joint surface,so as to verify the correctness of the theoretical model and obtain the dynamic characteristics of the system more clearly.