数控机床进给系统热误差分析与试验研究

发布时间：2018-09-12 09:24

【摘要】：随着制造业向高速高精度加工方向发展,热误差对机床加工精度的影响日趋严重,因此减小热误差是提高机床加工精度的重要途径。由于滑块与导轨、轴承与丝杠以及螺母与丝杠之间的摩擦会产生大量热量,因此进给系统作为数控机床上的主要热源,由温升所引起的热误差将降低机床进给运动的精度。本文以沈阳机床集团生产的VMC850E立式加工中心改造的试验平台上进给系统为研究对象,研究滚动直线导轨副和滚珠丝杠传动系统的温度场与热变形,为减小进给系统的热误差提供依据。本文的主要研究工作如下:(1)在理论研究方面,通过对热量传递的基本方式与定律、温度场与热变形基础理论以及导热微分方程等热基础理论的研究与分析后,确定出滚动直线导轨副和滚珠丝杠传动系统发热量以及热对流换热系数的计算方法和计算过程,为后续进给系统的温度场与热变形的有限元仿真分析提供依据。(2)建立滚动直线导轨副和滚珠丝杠传动系统的有限元模型,将热边界条件加载在有限元模型上分别对其进行稳态、瞬态温度场分析以及热—结构耦合分析,获得进给系统温度场与热变形的变化规律;通过仿真分析来研究影响滚动直线导轨副热误差的因素以及高速进给速度下滚珠丝杠传动系统的温度场与热变形的变化规律,同时提出减小滚珠丝杠传动系统热误差的有效方法。(3)依据试验目的与性能要求,设计试验平台的整体结构及试验载荷加载机构,自主搭建滚珠丝杠传动系统热误差研究试验平台。(4)对试验平台上进给系统进行温度场与热变形的试验研究,将试验得出的结果与热误差仿真分析的结果相比较,验证采用有限元分析方法获得的滚珠丝杠传动系统温度场及热变形结果的正确性。
[Abstract]:With the development of manufacturing industry in the direction of high-speed and high-precision machining, the influence of thermal error on machining accuracy is becoming more and more serious. Therefore, reducing the thermal error is an important way to improve the machining accuracy of machine tools. Because the friction between slider and guide rail, bearing and lead screw and nut and lead screw will produce a lot of heat, feed system is the main heat source on NC machine tool, the thermal error caused by temperature rise will reduce the precision of machine tool feed motion. In this paper, the temperature field and thermal deformation of rolling linear guide rail pair and ball screw drive system are studied by taking the feed system on the test platform of VMC850E vertical machining center produced by Shenyang Machine tool Group as the research object. It provides the basis for reducing the thermal error of the feed system. The main research work of this paper is as follows: (1) in the theoretical research, through the research and analysis of the basic ways and laws of heat transfer, the basic theory of temperature field and thermal deformation, and the heat conduction differential equation, etc. The calculation method and calculation process of heat transfer coefficient and heat convection heat transfer coefficient of rolling linear guide rail pair and ball screw drive system are determined. It provides the basis for the finite element simulation analysis of the temperature field and thermal deformation of the following feed system. (2) the finite element model of the rolling linear guide rail pair and the ball screw transmission system is established, and the thermal boundary condition is loaded on the finite element model to carry on the steady state respectively. The transient temperature field analysis and thermal-structure coupling analysis are used to obtain the variation of the temperature field and thermal deformation of the feed system. Through simulation analysis, the factors that affect the thermal error of rolling linear guide rail pair and the variation law of temperature field and thermal deformation of ball screw drive system under high speed feed speed are studied. At the same time, an effective method to reduce the thermal error of the ball screw drive system is put forward. (3) according to the test purpose and performance requirement, the whole structure of the test platform and the loading mechanism of the test load are designed. The thermal error test platform of ball screw drive system is built independently. (4) the temperature field and thermal deformation of feed system on the test platform are studied, and the results obtained are compared with the results of thermal error simulation analysis. The results of temperature field and thermal deformation of ball screw drive system obtained by finite element method are verified.
【学位授予单位】：沈阳理工大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TG659

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