机床“羊角”拨叉加工工艺及加工φ14.4mm孔夹具设计

摘 要

本论文完成了对机床“羊角”拨叉加工工艺及加工φ14.4mm孔夹具 的设计。在设计的前一部分，主要进行工艺卡的填写。首先， 分析零件的性能、用处和工作条件，明确零件的装配位置及其作用，找出其主要技术要求和关键技术问题，对零件进行工艺审查。然后，确定毛坯，拟定工艺路线，选择定位基面，确定加工所采用的设备、刀具、夹具、量具和辅助工具，确定各主要工序的技术要求及检验方法 。最后， 确定各工序的加工余量，计算工序尺寸和公差，确定切削用量和工时定额，进行技术经济分析，然后填写工艺文件。

第二阶段，进行夹具设计。纵观整条工艺路线，结合难易程度和夹具本身的特色，选定第三道钻?14.4mm孔的工序进行夹具的总体装配和夹具体的设计。首先，结合零件在该工序中需要达到的各项技术要求，初步拟定工件的定位、夹紧方案；然后，根据夹具设计原则以及夹紧力和夹紧点的确定原则进行局部零部件和夹具体的设计；最后，校核该夹具的精度。

关键词：羊角拨叉；机械加工；工艺；切削；夹具设计

目 录

内容摘要 ·························································································································· 1 引 言 ···························································································································· 3 1 设计任务说明 ············································································································ 4 1.1 羊角拨叉的功用 ····································································································· 4 1.2 设计任务 ················································································································· 4 2 零件工艺规程设计 ···································································································· 5 2.1 产量的确定 ············································································································· 5 2.1.1 生产类型的确定 ·································································································· 5 2.1.2 日生产量的确定 ·································································································· 5 2.2 毛坯的选择及毛坯图的绘制 ················································································· 5 2.2.1 毛坯的选择 ·········································································································· 5 2.2.2 毛坯-零件综合图的绘制方法 ············································································· 6 2.3 定位基准的分析与选择 ························································································· 7 2.3.1 基准的概念 ·········································································································· 7 2.3.2 基准选择原则 ······································································································ 7 2.3.3 定位基准的选择 ·································································································· 8 2.4 工艺路线的制定 ····································································································· 9 2.5 工艺卡的填写 ······································································································· 11 3 夹具设计 ···················································································································· 17 3.1 夹具的整体设计 ····································································································· 17 3.1.1夹具设计分析 ······································································································· 17 3.1.2 夹具结构方案的确定 ·························································································· 17 3.1.3 夹具的具体设计 ·································································································· 17 3.2 夹具的装配 ············································································································· 20 3.3 夹具的经济性分析 ································································································· 20 结 论 ·························································································································· 22 参考文献 ························································································································ 23

引 言

拨叉作为车床、铣床、镗床、钻床等各类机床及其他设备的传动装置变速时必不可少的零件，其加工精度直接影响传动装置的装配性能、变速性能、运行噪声等很多方面。因此，对拨叉的加工工艺的研究受到国内外学者的广泛重视。学者们不断提出新的加工工艺方案和改进以前的工艺方案。但是，由于拨叉类零件品种、规格繁多，加工时需要不同种类的加工设备，加之传统加工工艺落后，产品合格率不高，常常会影响整机装配，使拨叉零件的加工成为生产的瓶颈。因此，很有必要进一步的对拨叉类零件的加工工艺进行研究和改进，不断的提高拨叉类零件的加工精度。提高整机的整体性能。

本文主要对机床的“羊角”拨叉进行工艺分析和编制，并对加工过程中的重要工艺的专用夹具进行设计和研究。解决机床“羊角”拨叉加工中的瓶颈问题，提高拨叉的加工精度，使其更好的与整机配合，获得良好的整机性能。

同时，本课题的研究，也是对我这几年学习的全部知识总结和应用。初步具备了独立分析零件结构工艺性、编制零件加工工艺文件和加工过程中的重要工艺的夹具设计。熟悉和掌握了文献资料、技术资料和各种手册的查阅和运用。从中锻炼了自己的分析问题、解决问题的能力，为以后的工作打下了坚实的基础。

1 设计任务说明 1.1 羊角拨叉的功用

设计机床羊角拨叉零件的机械加工工艺规程及其机床夹具。拨叉是一种辅助零件，通过拨叉控制滑套与旋转齿轮的接合。滑套上面有凸块，滑套的凸块插入齿轮的凹位，把滑套与齿轮固连在一起，使齿轮带动滑套，滑套带动输出轴，将动力从输入轴传送至输出轴。摆动拨叉可以控制滑套与不同齿轮的结合与分离，达到换档的目的。该零件图纸如下：

图1 机床羊角拨叉零件图

1.2 设计任务

本次设计任务需完成毛坯选择、编排加工工艺、工装夹具设计、撰写产品说明书，以及图纸绘制等工作，图纸说明如下：

1．毛坯—零件综合图 2．工艺过程卡片 3．夹具装配图

1张 1套 1张 1张 1份

4．夹具体零件图 5．说明书