轿车骨架件连续冲压成形关键技术研究

发布时间：2019-06-10 15:05

【摘要】：2009年,中国以1379.10万辆的汽车产量超过日本、美国、德国等汽车制造强国成为世界上生产汽车最多的国家。随着汽车产量的连续增长和模具制造水平的不断提高,汽车覆盖件模具制造业也得到了快速发展。汽车覆盖件包括外覆盖件、内覆盖件和骨架类覆盖件。外覆盖件是指汽车车身外表形状的冲压件;内覆盖件是指汽车车身内部的冲压件,它和外覆盖件一起与骨架类覆盖件焊接后形成白车身;骨架类覆盖件(简称骨架件)是指连接内、外覆盖件起加强作用的冲压件。骨架类覆盖件与一般冲压件比较,具有结构尺寸大、形状复杂、多为空间曲面等特点。骨架类覆盖件一般采用连续冲压成形技术制造,通常需要经过冲裁、弯曲、局部变形、翻边、整形、冲孔、切断才能完成,成形难度较高。本文以宝马轿车BMW F45加强D柱(左/右)的连续冲压成形为研究对象,主要做了以下的工作:对加强D柱进行了产品冲压工艺性分析,设计了10工位的连续冲压工艺方案,设计了排样图;应用AUTOFORM软件模拟了加强D柱的连续冲压过程,预测了成形过程中可能出现的各种成形缺陷;研究了毛坯的精确设计方法;较为深入地研究了连续模结构设计;通过试模,验证了应用AUTOFORM软件进行有限元数值模拟的可靠性和准确性以及模具结构设计的合理性。实践证明,研究结果对于设计轿车骨架类覆盖件连续冲压工艺方案和连续模结构具有指导意义。本文的研究内容和结论如下:(1)骨架类覆盖件一般为左、右对称件,可以考虑在同一套模具上冲压成形,这样可以降低模具制造成本。(2)骨架类覆盖件冲压工艺方案一般是冲导正孔、切边等分离工位在最前,局部变形、弯曲、翻边、整形等成形工位在中间,冲孔、切断等工位在最后。(3)骨架类覆盖件一般不安排修边工序,而采用精确设计毛坯外形尺寸的方法。应用AUTOFORM软件可以满足毛坯外形尺寸的要求。(4)一般情况下,应用AUTOFORM软件对骨架类覆盖件进行单工位多工序有限元数值模拟能够满足成形分析需求。如果在模拟中出现破裂、起皱等缺陷,可通过修改冲压工艺方案或修改毛坯形状的方法进行重新模拟予以解决。(5)应用AUTOFORM软件进行单工位多工序有限元数值模拟,可以较准确地预测成形后零件的厚度变化,对加强D柱,其最大相对误差为2.88%。(6)应用AUTOFORM软件可预测回弹的大小,并可做回弹补偿。轿车骨架类覆盖件的回弹量通常较小,在设计模具的初期可以不考虑,在模具设计的后期根据产品的实际回弹量来修改模具的结构。(7)以加强D柱为例,对骨架类覆盖件连续模的结构进行了较为深入的研究,总结了设计方法和要点,试验证明方法可行。(8)通过冲压试验,证明确定的冲压工艺方案以及有限元数值模拟结果和模具设计方法切实可行,对实际骨架类覆盖件的连续冲压成形工艺和模具设计具有指导作用。
[Abstract]:In 2009, China overtook Japan, the United States and Germany in producing 13.791 million cars to become the world's largest producer of cars. With the continuous growth of automobile output and the continuous improvement of die manufacturing level, the automobile panel die manufacturing industry has also been developed rapidly. Automobile panels include external panels, inner panels and skeleton panels. The outer panel refers to the stamping part with the appearance shape of the automobile body, and the inner panel refers to the stamping part inside the automobile body, which, together with the outer panel, forms a white body after welding with the skeleton cover. Skeleton panel (abbreviated as bone frame) refers to the stamping parts which connect the inner and outer panels to strengthen. Compared with the general stamping parts, the skeleton panel has the characteristics of large structure size, complex shape, spatial surface and so on. Skeleton panels are generally manufactured by continuous stamping technology, which usually need to go through blanking, bending, local deformation, flanging, shaping, punching, cutting and cutting, so the forming difficulty is high. In this paper, the continuous stamping forming of BMW F45 reinforced D column (left / right) of BMW car is taken as the research object. The main work is as follows: the stamping process of the strengthened D column is analyzed, and the continuous stamping process scheme of 10 stations is designed. The layout diagram is designed. The continuous stamping process of strengthening D column is simulated by AUTOFORM software, and all kinds of forming defects in the forming process are predicted, the accurate design method of blank is studied, and the structure design of continuous die is deeply studied. The reliability and accuracy of finite element numerical simulation with AUTOFORM software and the rationality of die structure design are verified by die test. The practice proves that the research results are of guiding significance for the design of continuous stamping process scheme and continuous die structure of car skeleton panels. The research contents and conclusions of this paper are as follows: (1) the skeleton panels are generally left and right symmetrical parts, which can be considered for stamping on the same set of dies. In this way, the die manufacturing cost can be reduced. (2) the stamping process scheme of skeleton panel is generally punching the leading hole, cutting edge and other separation stations in the front, local deformation, bending, flanging, shaping and other forming positions in the middle, punching. Cutting off equal station at the end. (3) skeleton panels generally do not arrange trimming process, but adopt the method of accurate design of blank shape and size. The application of AUTOFORM software can meet the requirements of blank shape and size. (4) in general, the application of AUTOFORM software to single station multi-process finite element numerical simulation of skeleton panels can meet the requirements of forming analysis. If the defects such as rupture and wrinkling occur in the simulation, they can be solved by modifying the stamping process scheme or modifying the blank shape. (5) the finite element numerical simulation of single station and multi-process is carried out by using AUTOFORM software. The thickness change of the parts after forming can be predicted more accurately. For the strengthened D column, the maximum relative error is 2.88%. (6) the springback size can be predicted by using AUTOFORM software, and springback compensation can be made. The springback of car skeleton panels is usually small, which can not be taken into account in the early stage of die design, and the structure of the die can be modified according to the actual springback of the product in the later stage of die design. (7) take strengthening D column as an example. The structure of continuous die for skeleton panel is studied deeply, and the design method and key points are summarized. The test results show that the method is feasible. (8) through stamping test, It is proved that the determined stamping process scheme, finite element numerical simulation results and die design method are feasible, which can guide the continuous stamping forming process and die design of actual skeleton panels.
【学位授予单位】：华南理工大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TG386;U466

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