高速静压膨胀夹头夹持特性分析

发布时间：2018-04-26 12:49

本文选题：静压膨胀夹头 + 有限元分析　；参考：《哈尔滨理工大学》2017年硕士论文

【摘要】：高速加工工具系统是高档数控机床的关键部件之一,其中,刀具的夹持特性,直接影响零件的加工质量和加工安全,不同夹持方式需要在不同切削工况下应用。目前,基于静压膨胀夹紧原理开发的静压膨胀式夹头可以用来夹持各类刀具进行切削加工,实现超高精度夹紧刀具,其性能优良,广泛应用于机械制造业,能在半精加工和精加工中有效地提高被加工工件的表面质量。静压膨胀夹头的夹持回转精度和重复夹紧精度高、夹持力大;具有一定的阻尼减振效果,切削噪声相对较小;在装卸刀具时简单方便。本文对静压膨胀夹头的夹持特性进行深入研究,揭示了其基本规律,对静压膨胀夹头的设计与应用中存在的关键问题具有重要理论价值与实际意义。在相关研究成果的基础上,运用弹性力学、动力学、有限元分析法、数值分析和可靠性分析,对静压膨胀夹头进行建模、静动态特性分析、可靠性分析与仿真研究:首先,在弹性力学基础上,建立夹头的受力模型,运用有限元分析软件对静压膨胀夹头进行静态特性分析,初步探求其夹持状态;其次,考虑到静压膨胀夹头夹持部位关节的弹性性质,关节的约束并非完全刚性,采用线性弹簧和扭转弹簧对夹持部位进行表征,建立夹头/刀具系统的弹性约束模型,进行数值计算,得到了固有频率,并与有限元分析结果进行对比,对比结果具有很好的一致性;再次,在动力学基础上,运用有限元软件对静压膨胀夹头进行了模态分析、谐响应分析和瞬态动力学分析,获取夹头的动态特性;最后,考虑到静压膨胀夹头在使用中安全可靠性问题,基于结构可靠性理论,确定关键设计参数,对夹持结构进行可靠性分析,研究外部载荷和结构参数的随机变量对最大夹持变形和最大等效应力影响,得到了相关系数并进行灵敏度分析,获取结构可靠度。
[Abstract]:High-speed machining tool system is one of the key parts of high-grade NC machine tools. The clamping characteristics of cutting tools directly affect the machining quality and machining safety of parts. Different clamping methods need to be applied in different cutting conditions. At present, the hydrostatic expansion chuck developed based on the principle of hydrostatic expansion clamping can be used to clamp various kinds of tools for cutting and machining, and achieve ultra-high precision clamping tool, which has excellent performance and is widely used in mechanical manufacturing. It can effectively improve the surface quality of the workpiece in semi-finishing and finish machining. The clamping accuracy and repeated clamping accuracy of static pressure expansion chuck are high, the clamping force is large, it has certain damping effect, the cutting noise is relatively small, and it is simple and convenient in loading and unloading tool. In this paper, the clamping characteristics of the hydrostatic expansion chuck are deeply studied, and its basic law is revealed, which is of great theoretical and practical significance to the design and application of the hydrostatic expansion chuck. Based on the related research results, the static expansion chucks are modeled, static and dynamic characteristics are analyzed, reliability analysis and simulation studies are carried out by means of elastic mechanics, dynamics, finite element analysis, numerical analysis and reliability analysis. On the basis of elastic mechanics, the stress model of the chuck is established, and the static characteristic of the static expansion chuck is analyzed by using the finite element analysis software, and the clamping state of the chuck is preliminarily explored. Considering the elastic properties of the joint at the clamping position of the static expansion chuck, the constraint of the joint is not completely rigid. The clamping position is characterized by linear spring and torsional spring, and the elastic constraint model of the chuck / tool system is established. By numerical calculation, the natural frequency is obtained, and the results are compared with the results of finite element analysis. Thirdly, on the basis of dynamics, the modal analysis of static expansion chuck is carried out by using finite element software. Harmonic response analysis and transient dynamic analysis are used to obtain the dynamic characteristics of the chuck. Finally, considering the safety and reliability of the hydrostatic expansion chuck in use, the key design parameters are determined based on the structural reliability theory. The influence of random variables of external load and structural parameters on the maximum clamping deformation and the maximum equivalent stress is studied. The correlation coefficient is obtained and the sensitivity analysis is carried out to obtain the reliability of the structure.
【学位授予单位】：哈尔滨理工大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TG659;TG75

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