汽车半轴螺母冷锻成型工艺研究

发布时间：2019-03-28 17:22

【摘要】：传统对汽车半轴螺母的加工采用的是热镦、切削加工的方式,生产环境恶劣,低效耗材,成型产品质量较差,.基于此,提出了汽车半轴螺母精锻成型工艺的研究,并针对两种典型的螺母进行了相关技术的探究。简单阐明了金属体积成型的特点、变形方式及有限元理论等,列举了六角开槽螺母的典型生产工艺,以此为基础,设计了六角开槽螺母的两套六工位冷锻成型工艺方案,分析了螺母的成型难度以及影响成型的若干因素,合理分配了各道工序间材料的变形量,并从理论角度说明了两工艺方案实施的可行性。研究了 SCM435合金钢材料的力学行为,并建立了不同温度及应变率条件下的J-C本构模型,完成了两套成型工艺系统的有限元建模、材料断裂准则相关关键参数的选择与设置及数值计算,基于仿真结果分析确定成型工艺路线。简述了浮动反挤压成成型的特点,以承受高负载的反挤压下冲头的磨损量为优化目标,上冲头冲压速度、接触面间的摩擦系数等为因素水平,结合多因素多水平正交试验,获取最佳组合,并根据结果指导完成模具的设计工作。最后,立足企业,将偏心螺母作为典型汽车半轴螺母来验证有限元模拟分析应用于汽车半轴螺母冷锻成型工艺的可行性。基于有限元技术,建立了成型工艺优化数学模型,并选定了主要的目标函数来优化工艺,确定最终成型工艺,完成偏心螺母多工位模具的设计。最后,结合企业现场试验,采用多工位自动冷镦机,进行偏心螺母的试制,与仿真试验比较,以判断有限元模拟试验的可靠性。
[Abstract]:The traditional way of machining automobile semi-axle nut is hot upsetting and cutting, the production environment is bad, low efficiency consumables, the quality of molding products is poor. Based on this, the research on precision forging process of automobile semi-axle nut is put forward, and two typical nuts are discussed in this paper. The characteristics, deformation mode and finite element theory of metal volume forming are simply expounded. The typical production technology of hexagonal slotted nut is enumerated. On the basis of this, two sets of six-station cold forging process scheme for hexagonal slotted nut are designed. The difficulty of nut forming and some factors affecting forming are analyzed, and the deformation of materials in each process is reasonably allocated. The feasibility of the implementation of the two technological schemes is explained from the point of view of theory. The mechanical behavior of SCM435 alloy steel was studied, and the J-C constitutive model under different temperature and strain rate was established, and the finite element modeling of two sets of forming process system was completed. The selection and setting of key parameters of material fracture criteria and numerical calculation are used to determine the forming process route based on the analysis of simulation results. This paper briefly describes the characteristics of floating backward extrusion forming, taking the wear amount of the lower punch under high load as the optimization objective, the stamping speed of the upper punch and the friction coefficient between the contact surfaces as the factor level, and combining with the multi-factor and multi-level orthogonal test. Get the best combination, and guide the mold design work according to the results. Finally, based on the enterprise, the eccentric nut is taken as a typical automobile semi-shaft nut to verify the feasibility of the finite element simulation analysis applied to the cold forging process of automobile semi-shaft nut. Based on the finite element technique, the mathematical model of forming process optimization is established, and the main objective function is selected to optimize the process, the final forming process is determined, and the design of multi-station die for eccentric nut is completed. Finally, a multi-station automatic cold heading machine is used to test the eccentric nut and compare it with the simulation test in order to judge the reliability of the finite element simulation test.
【学位授予单位】：上海应用技术大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TG62;TG316

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