汽车钢质同步环精密成形与提高模具寿命的研究.doc

汽车钢质同步环精密成形与提高模具寿命的研究

摘    要

本文针对重型汽车、大客车上使用的钢质同步器齿环一次锻造成形的关键和
难点问题进行了深入研究。由于同步器齿环的齿形是渐开线的，齿部圆角半径小，在成形过程中容易出现齿形部分充填不饱满。同时，在成形过程中，模具受力相当复杂；在凹模齿形型腔入模圆角处，当材料从横向与纵向流入型腔时，激烈的塑性变形引起模具表层温度迅速上升，在这种情况下模具软化加剧且磨损严重，造成模具使用寿命低。另外，齿形和外表面属于精密成形，成形之后不再进行机加工，对成形过程的工艺参数控制要求很高。
为解决上述问题，利用计算机数值模拟手段，全面分析了汽车钢质同步环锻造成形工艺，对成形中材料的流动方式、成形过程、缺陷预测、模具结构优化进行了研究，分析了不同成形阶段材料的流动情况及模具结构与坯料尺寸对锻件质量的影响，针对模具寿命问题，从模具温度和应力的角度重点对钢质同步环成形过程中凹模的寿命进行了研究。
实验结果表明：通过对同步齿环成形过程分析，优化工艺及模具结构，提高了模具寿命和材料利用率。

关键词：钢质同步环，精密成型，数值模拟，模具寿命，成型工艺

ABSTRACT

This topic is originated from the Sichuan Luzhou Changjiang Machinery Limited Company which project is studying on precisely deforming of the automobile steel synchronous ring and enhancing the die life.
Steel gear of synchronizer is an asymmetric ring thin wall part with several spline
teeth. It is mainly used in gearshift. It is an issue for forging process and mould design because its complex shape which results in insufficient filling, folding and so on. With the development of auto industry, a lot of gears of synchronizer are needed, but it is difficult to get a good satisfactory product in our country.
    The key problems of the copper gear which is used in heavy-duty car and big-bus
during the forging process are discussed in this paper. The teeth are not fully filled usually because of  its small radius due to its involutes profile.Meanwhile the die life is very short because the stress state is quite complex. When the material flows in the cavity along transverse and longitudinal direction, drastic deforming of the billet result that the temperature on the surface raises rapidly, die soften and some parts of the die severe wear. On the other hand,the gear won’t be manufactured any more so it is very important to control the processing parameters.
To overcome these problems, the forming of the gear is analyzed based on numerical simulation,also,studying on the flow of material, forming process, flaw prediction and the optimization of the mould structure. The rules of the material flowing in the cavity in different forming stages and the effects of the size the billet and the mould structure on the quality of the piece are analyzed.Aim at the life time of mould, the life time of the die is studied based on the temparature and stress.
Experiment verification shows through the analysis of the forming of Steel gear of synchronizer,optimization of the technics and mould structure,the life time of die and the using ratio of material are improved.

Key words：Steel gear of synchronizer, Precision forming, Numerical simulation, Mold life, Forming technology
 
 

 
目   录

摘要 Ⅰ
ABSTRACT Ⅱ
1绪论 1
  1.1 课题来源及意义 1
  1.2国内外同类技术比较 1
1.3现阶段存在的主要问题与原因 1
1.4 本课题的研究内容与目标………………………………………………...2
1.5 本课题的主要研究方法………………………………………………......2
2 同步环精密模锻工艺设计…………………………………………….4
2.1 零件的工艺性分析………………………………………………………4
2.2 同步环精密模锻成形工艺要求…………………………………………….4
2.3 同步环精密模锻工艺制定………………………………………………...5
2.3.1 工艺方案比较选择…………………………………………………..5
2.3.2 锻件图制定………………………………………………………...5
2.3.3 坯料制备…………………………………………………………..6
2.3.4 同步环成形工艺………………………………………….................7
3 同步环精密成型数值模拟与实验研究……………………………….8
3.1 数值模拟的基本理论…………………………………………………….8
3.1.1 金属塑性成型概述…………………………………………………..8
3.1.2 基本假设与基本模型………………………………………………...8
3.1.3 粘塑性基本方程……………………………………………………..9
3.2 模型简化及模拟条件…………………………………………………….9
3.3 成形过程分析…………………………………………………………..11
3.3.1 无飞边槽模具结构成形……………………………………………...11
3.3.2 带阻力墙模具结构成形……………………………………………...14
3.3.3 基本飞边槽模具结构成型……………………………………………16
3.3.4 小结……………………………………………………………...17
3.4 坯料定位方式优化……………………………………………………...19
3.5 实验条件……………………………………………………………...20
3.5.1 模具预热………………………………………………………….20
3.5.2 模具冷却………………………………………………………….20
3.5.3 其他……………………………………………………………...20
4汽车钢质同步环模具设计……………………………………………..21
4.1 模具设计概述………………………………………………………21 
4.1.1 模具工作尺寸与锻件尺寸的关系………………………………………21
4.1.2 模具工作尺寸影响因素………………………………………………22
4.1.3 模腔形状设计………………………………………………………23
4.1.4 模具凸、凹模及装配图………………………………………………25
4.3 模具材料………………………………………………………………26
5模具制造………………………………………………………………..28
5.1模具工作环境概述……………………………………………………….28
5.2 科学合理选择模具材料…………………………………………………..28
5.3 模块科学合理锻造……………………………………………………....29
5.4 模具强化热处理………………………………………………………...29
5.4.1 模具强韧化处理…………………………………………………….30
5.4.2 模具表面强化处理…………………………………………………..30
6 同步环成形问题对策………………………………………………….32
6.1 模具的冷却……………………………………………………………32
6.2 顶料装置………………………………………………………………33
6.3 模具的堆焊…………………………………………………………….34
6.4 模具的渗氮处理………………………………………………………...35
7 结论…………………….........................................................................36
参考文献………………………………………………………………….37
致谢……………………………………………………………………….39