无相位角的多拐曲轴精锻工艺开发及模具设计（本科毕业论文设计）.doc

摘 要

汽车发动机曲轴，是汽车工业中一种典型的复杂模锻件，其成形难度大，对成形工艺要求高。近年来，由于汽车的重载、高速和高可靠性的要求，对曲轴的
性能要求也越来越高，因此如何改进曲轴的加工工艺以尽可能地提高曲轴的机械
性能和寿命就显得尤为重要。
曲轴类锻件锻造工艺复杂，其可行性、稳定性、成形质量（含充满与否、折
叠、组织缺陷）、材料利用率以及如何降低载荷提高模具使用寿命等，都是在制
订曲轴成形工艺过程中必须重点考虑的。
本文对曲轴的精密模锻成形工艺和国内外研究现状作了简要介绍，选择平面
四拐曲轴作为典型件，详细介绍了曲轴模锻工艺的分析和设计，运用三维造型软件在CAD平台下进行曲轴的模锻工艺与模具设计中相关问题的 CAD实体三维造型。根据刚塑性有限元基本原理，利用数值模拟软件对曲轴的成形过程进行数值模拟，分析了飞边槽、阻力墙参数对曲轴精密模锻成形过程中的金属流动情况、模具型腔充填情况以及材料利用率的影响。由模拟结果，分析造成锻件缺陷的因素并通过各种方案的模拟结果,对比选出能够锻出合格锻件的工艺及模具参数。


关键词：曲轴，模锻，模具设计，工艺分析，数值模拟,工艺优化











ABSTRACT

The crankshaft of automobile is one typical die forging part with complex structure,which is usually formed by a complicated process under the high forming requirement.In recent years, due to the demand of high performance of automobile, such as heavy load, high speed, high reliability, etc., the requirement of crankshaft’s performance has also been uprated greatly. Therefore, it is of great importance to optimize the forging process to improve the mechanical performance of crankshaft.
The forging process of crankshaft is very complicated, the feasibility, stability,
quality of forming (including fulfilling, wrinkle and structure defect), material yield and mould lifetime, etc. are all the key factors that should be considered with emphasis during the forging process decision
This paper briefly introduces the precision die forging process of crankshaft and the research status of the forging development home and abroad, choosing the plane four turner crankshaft as a typical forging part, as the typical forge piece, particularly introduced the author’s work on analysis and designs of production processes, By the use of the CAD system , the three-dimensional model of crankshaft and die can be set up parametrically.According the rigid-plastic finite element method, using the finite element numerical simulation soft,the influence on the metal flow, mould filling,and die load, and material yield from the parameters of web and resistance wall are analyzed. Using simulate results, find and analyzes the factors caused the defects of forging, And by the simulate results,elected the production processes and die parameters to product qualified crankshaft forge piece.


Keywords：crankshaft ,die forging，die design，technology analysis, numerical simulation, technology optimize


目 录

中文摘要 I
ABSTRACT II
1绪论 1
1.1引言 1
1.2 曲轴的自由锻工艺 2
1.3曲轴的模锻工艺 2
1.4国内外曲轴锻造研究现状 2
1.5本课题的主要研究内容 3
2曲轴模锻成形工艺设计 5
2.1精密模锻工艺概述 5
2.2曲轴的模锻工艺概述 5
2.2.1曲轴的分类 5
2.2.2曲轴锻造工艺分类 6
2.2.3模锻法加工曲轴 7
2.3曲轴精锻工艺分析 7
2.4锻件的材料特性 9
2.5锻造设备类型的选择 10
2.6设备吨位的选择 10
2.7热锻件图的设计 12
2.8制坯工步的确定 14
2.8.1制坯工步的作用 14
2.8.2初拟计算毛坯 15
2.9坯料尺寸的确定 17
2.10制定工艺卡片 17
3曲轴模具设计 18
3.1模具设计的CAD/CAM技术 18
3.2热模锻压力机模具设计要领 18
3.3模块的设计 19
3.3.1模块的形式与尺寸 19
3.3.2飞边槽的形式和尺寸 19
3.3.3模膛的设计 20
3.3.4排气孔的设计 21
3.3.5模架的设计 22
4曲轴成形过程的数值模拟和分析 25
4.1数值模拟的意义 25
4.2刚粘塑性有限元法简介 25
4.3锻造过程模拟 26
4.3.1滚挤制坯的模拟 26
4.3.2采用常规飞边槽模具结构终锻的模拟 27
4.4模拟结果分析 28
4.5造成锻造缺陷的影响因素分析 29
4.6方案的优化和改进 30
4.6.1模具结构的优化 30
4.6.2制坯模膛的优化 35
4.6.3坯料尺寸的优化选择 38
4.6.4方案确定 39
5结论 40
参考文献 42
致 谢 44