| High speed and high precision has gradually become the main development trend for Modern CNC machine and the requirement of key assembly for numerical control machine tool is higher and higher. With the increasingly improvement of the accuracy of machine tools, thermal characteristics of machine tool feed system has more and more big influence on the machining accuracy of machine tool eventually. So research on the modeling method of thermal characteristics for CNC machine tool feed system and its effect on the processing performance is of great significance.The transmission structure In the modern CNC machine tool feed system varies from each other. One of widely used is rotating translational structure that uses Ball screw nut pair to drive and the linear rolling guideway to orientate. Study of modeling method of thermal characteristics for linear rolling guide and the ball screw nut pair and further analysis for the influence of the machine final processing performance is of great significance to improve the level of product design. Thermal characteristics model of feed system for machine tool feed system will provide the theory basis for the thermal deformation and thermal error compensation.Based on the key features of machine tool feed system as the research object, this paper analyses the thermal characteristics of feed system and its further effect on the performance of machine tool.The main research work of this paper is as follows:First of all, on the basis of related literature at home and abroad, this paper summarized and reviewed the thermal characteristics situation of machine tool feed system, elaborated the research significance and content and ascertained the main research content and method of the subject;Secondly, based on the theory of heat transfer and mechanics of elasticity, this paper established of the analytical model of the temperature and thermal strain mathematical model for the linear rolling guide, preliminarily predicted the temperature field and stress field of rolling linear guide and ball screw;Then, by means of heat transfer and thermal elastic mechanics, mathematical, finite element simulation as research tools, this paper set up the finite element model of ball screw and linear rolling guide rail, analyzed the feed system in detail, calculated the temperature field and the time required to reach thermal equilibrium for the ball screw feed system and the linear rolling guide, and finally based on the temperature field conducted the hot structure coupling analysis in order to gain the thermal deformation and stress distribution of the lead screw and guide rail. Thus put forward the effective measures to reduce the thermal deformation;Finally, through the experiment, this paper by means of the thermal resistance and other related instruments to obtain temperature and thermal strain values for corresponding parts of feed system. Thus compare these values with the above theory and the simulation results to prove the reliability and correctness of the result. |
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