伞齿轮冷精锻成形工艺开发及模具设计（本科毕业论文设计）.doc

摘 要

闭塞式精锻工艺属于金属塑性加工的先进工艺，齿轮精锻就是通过精密锻造直接获得完整齿形，且齿面不需或仅需少许精加工即可使用的齿轮制造技术。它有效地改善了齿轮的组织和性能。精锻使金属三向受压，晶粒及组织变细，致密度提高，微观缺陷减少；精锻还使金属流线沿齿形连续均匀分布，提高了齿轮的机械性能。且精锻齿轮的精度能达到精密级公差、余量标准，使得工件不需或者只需少量精加工就可进行热处理或直接使用，提高了生产效率及材料利用率，降低了生产成本，因此大大提高了齿轮的市场竞争能力。
冷精锻通常指的是在室温下对毛坯进行精密锻造。采用冷精锻工艺的优点是:可以降低原材料消耗，材料利用率高，锻压后的金属材料晶粒组织更加细小而致密，金属流线不被切断加上所产生的加工硬化特征，可使锻件的强度大为提高，可以获得较高的尺寸精度和较高的表面光洁度。但其缺点是:成形单位压力大，模具易磨损，损坏，因此要求模具材料好;对成形设备要求较高，吨位要大，除要求锻压设备应有较大的强度以外，还要求较好的刚度;且通常要在锻压前对坯料做磷化皂化处理，且处理的好坏直接关系到后序锻造的效果。本课题主要是应用模拟软件对不同的情况进行模拟分析，从材料损伤因子，充填效果方面来确定成型工艺。


关键词：半轴齿轮，闭塞式冷精锻，模拟分析，损伤因子，模具设计













ABSTRACT

Enclosed-die forging process is one of the advanced processes in the field of metal plasticity shaping. Full gear-shape can be obtained through precision forging process, and the tooth need no or little precision machining only. The structure and performance of gear can be improved effectively through this process. The process can make material receiving pressures in three directions. So it can attenuate crystal grains, improve the density and decrease microcosmic flaws. It can also make metallic streamline on teeth more continuous and symmetrical, and lead to the improvement of mechanical performance of gear. The precision of gear can reach very high level, resulting in that the workpiece needs no or little machining only to be heat treated or used directly. The process improves producing efficiency and use ratio of materials, decreases producing cost. Therefore the competing ability of gears is improved greatly。
Cold precision forging usually refers to the right rough at room temperature for precision forging. With cold precision forging of the advantages are: lower raw material consumption, high utilization of materials, forging the metal material grain organizations more small and compact, metal flow is not cut off the line with the characteristics of the work-hardening, forging will Greatly increased the intensity will be entitled to a higher dimensional accuracy and a high surface finish. But its disadvantages are: forming load is large, die easy to be damage, die material called good，higher on the forming equipment, and tonnage should be large,；with the exception of forging equipment requirements should be greater intensity, also demanded better stiffness and usually do saponification and phosphating before forging, and handling will have a direct relationship to the sequence after forging results. The main issue is the application of a simulation software to simulate the different circumstances of the material damage factor, to determine the effect of filling process.


Key words： half axle gear, enclosed-die cold precision forging, simulation analysis,
damage, die design

目 录

中文摘要 Ⅰ
ABSTRACT Ⅱ
1绪论 1
1.1 引言 1
1.2 国内外研究现状 1
1.3 主要研究内容 2
1.4 研究的目的和意义 2
2 闭式模锻概述 4
2.1 引言 4
2.2 闭式模锻工艺的制定 5
2.2.1 锻件的工艺性分析 5
2.2.2 闭式模锻工艺过程的制定 5
3 齿轮成形工艺分析及设计 6
3.1 冷精锻 6
3.2 热精锻 6
3.3 温精锻 6
3.4 工艺方案制定 7
3.4.1工艺性方案 7
3.4.2工艺比较 7
3.5 锻件图制定 8
3.6毛坯选择 9
3.6.1毛坯体积确定 9
3.6.2毛坯形状选择 9
4 金属塑性成形过程的分析方法 11
4.1 概述 11
4.2金属塑性成形过程的有限元仿真技术 11
4.2.1金属塑性成形过程的有限元仿真技术概述 11
4.2.2金属塑性成形过程的刚(粘)塑性有限元法概述 12
4.2.3金属体积成形过程的有限元模拟概述 12
5 关于坯料尺寸确定的模拟分析 14
5.1 不同坯料尺寸下齿轮的充填效果 14
6 关于成形温度确定的模拟分析 16
6.1 40Cr极限损伤因子的计算 16
6.1.1 40Cr的动态压缩试验 16
6.1.2 40Cr虚拟镦粗实验 16
6.2不同温度对40Cr损伤因子的影响 19
6.2.1 冷锻 19
6.2.2 温锻 21
6.3本节模拟结果总结 27
7 模具设计及三维造型 29
7.1 概述 26
7.2齿轮锻件的三维实体造型 29
7.3凹模型腔造型 31
7.4模具总装图 32
7.5工作原理 33
7.6设备选择 33
8 结论 34
9 致谢 35
参考文献 36