筒形零件强制润滑拉伸的研究cad

摘要
圆筒件的拉伸是一种重要的板料成形方法，从变形力学上看由毛坯成形为成品是一个复杂过程。目前圆筒件的拉伸工艺计算大多利用极限拉伸系数mc来判定，实际需要的拉伸次数而极限拉伸系数mc则是在某一特定的实验条件下试验出来的。经验数据这些实验条件包括工件及坯料尺寸材质模具圆角半径润滑状况和压边情况等等，对于实际生产中的每一次设计来说这些条件是有差异的，在圆筒件的拉伸实践中虽然理论分析与经验积累已为工艺方案的制定提供了依据与原则，但这仅规定了选择参数的大致范围在可行域内参数的选择仍依靠经验一组工艺参数往往能够保证工艺过程的可行，但并不能保证其最优不能确保成形过程省力省功柔性并达到节约材料提高工件性能的目的，因此进行圆筒件极限拉伸系数的优化设计十分必要。
目前，国内外对极限拉伸系数进行的研究较多文献中详细地总结了板料成形中圆筒件极限拉伸系数的若干影响因素，并基于最大承载原则提出了一些计算圆筒件极限拉伸系数的实用公式，但是利用计算机对极限拉伸系数进行优化设计的报道仍较少，本文在利用国内外各种文献的基础上总结出了计算圆筒件拉伸过程中危险断面最大拉应力的公式，并据此建立了一个合理的数学模型再利用复合形法对圆筒件极限拉伸系数进行了优化伸中的危险断面在板料凹模圆角区和筒壁区相交处,建立了相应的拉伸力的计算公式,并获得了拉伸破裂临界状态时极限拉伸力及径向应力表达式。推导出了拉伸破裂最大压边力的公式,指出实际拉伸时最佳压边力应在防皱最小压边力和拉破最大压边力之间选取,同时根据该结果也能计算液体压力与最小拉伸系数的关系。计算结果表明,该液压拉伸方法可大幅度提高拉伸变形程度,值得在工业实际中推广应用。

关键词  筒形件;液压拉伸;压边力; 极限拉伸；润滑
Cylindrical tensile parts of the study forced lubrication
Abstract
Cylindrical pieces of drawing is an important sheet metal forming methods, from the deformation of the mechanical point of view by the rough shape for the finished product is a complex process. Cylindrical pieces of the current process of drawing the limits of computing most of the use of drawing to determine the coefficient of mc, the actual number of needs and the limits of deep drawing coefficient mc is in the experimental conditions of a particular test out the next. Empirical data of these experimental conditions including the size of the workpiece and the blank mold material fillet radius Blankholder lubrication conditions and circumstances, etc., for the actual production of each design there is a difference between these conditions and
Parts in the cylinder drawing practice and experience while the accumulation of theoretical analysis for the technology program has provided the basis for the development and principles, but provides only the general parameters of the scope of choice, where feasible, the region still depend on the choice of parameters of the experience of a group of process parameters often to ensure a viable process, but can not guarantee that the optimal effort can not ensure that the forming process and the province of flexible savings reactive materials to enhance the performance of the purpose of the workpiece, the cylindrical piece to the limit of deep drawing coefficient is necessary to optimize the design.
At present, domestic and international factors on the limit drawing study in more detail in the literature are summarized in sheet metal forming cylindrical pieces of drawing the limits of a number of factors affect the factors and principles based on the maximum load calculation of a number of cylindrical pieces of ultimate tensile deep practical formula coefficient, but the use of computer drawing of the limits of design to optimize the coefficient is still less reported in this paper using a variety of literature at home and abroad based on the calculation of cylinder summed up the process of drawing the maximum tensile stress the risk of cross-section formula,
And thus established a mathematical model of a reasonable re-use complex method of drawing the limits of cylindrical pieces of optimized coefficients in the risk of deep cross-section of sheet metal die in the fillet area and cylinder wall interface area, the establishment of the corresponding Drawing the formula for calculating the force, And the breakdown of the critical state of deep drawing force at the limit and the expression of radial stress. Derived from the breakdown of the biggest drawing BHF formula, pointing out that when the actual best drawing BHF should be wrinkle-free minimum blank holder force and pull the biggest break to select between the blank holder force and at the same time according to the results of the liquid can be calculated pressure and the smallest coefficient of the relationship between the drawing. The results show that the method of hydraulic deep drawing substantial increase in the degree of deformation, it is worth in the industrial application in practice.

Keywords　Tube; hydraulic deep drawing; BHF; limit drawing coefficient

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