机床“羊角”拨叉加工工艺及孔加工夹具设计

网络教育学院本科生毕业论文（设计）题目：机床“羊角”拨叉加工工艺及孔加工夹具设计学习中心：广东江门奥鹏学习中心层次：专科起点本科专业：机械设计制造及其自动化年级：2009年秋季学号：091182411014学生：罗礼胜指导教师：王爽完成日期：2011年9月17日机床“羊角”拨叉加工工艺及孔加工夹具设计1内容摘要本论文完成了对机床“羊角”拨叉加工工艺及孔加工夹具的设计。本论文完成了对机床“羊角”拨叉加工工艺及钻孔夹具的设计。在设计的前一部分，主要进行工艺卡的填写，流程如下：首先是分析零件基本特征；其次根据前面的分析来选择毛坯；再次设计工艺规程：包括制定工艺路线，选择基准面等；然后进行工序设计，即选择机床，确定加工余量，工序尺寸及毛坯尺寸，切削用量待参数；最后编制工艺文件。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，选定孔加工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；工艺卡；切削；夹具设计机床“羊角”拨叉加工工艺及孔加工夹具设计2目录内容摘要·····························································································1引言·······································································错误!未定义书签。1.1羊角拨叉的功用·····················································错误!未定义书签。1.2设计任务······························································错误!未定义书签。2零件工艺规程设计····················································错误!未定义书签。2.1产量的确定···························································错误!未定义书签。2.1.1生产类型的确定···················································错误!未定义书签。2.1.2日生产量的确定···················································错误!未定义书签。2.2毛坯的选择及毛坯图的绘制······························································62.2.1毛坯的选择·················································································62.2.2毛坯-零件综合图的绘制方法···································错误!未定义书签。2.3定位基准的分析与选择············································错误!未定义书签。2.3.1基准的概念·················································································72.3.2基准选择原则··············································································82.3.3定位基准的选择···········································································92.4工艺路线的制定···········································································102.5工艺卡的填写··············································································143夹具设计························································································203.1夹具的整体设计·············································································203.1.1夹具设计分析··············································································203.1.2夹具结构方案的确定····································································223.1.3夹具的具体设计··········································································243.2夹具的装配···················································································253.3夹具的经济性分析··········································································26结论·····························································································28参考文献···························································································29机床“羊角”拨叉加工工艺及孔加工夹具设计3引言机械设计制造及其夹具设计是我们融会贯通三年所学的知识，将理论与实践相结合，对专业知识的综合运用训练，为我们即将走向自己的工作岗位打下良好的基础。机械加工工艺是规定产品或零件机械加工工艺过程和操作方法，是指导生产重要的技术性文件。它直接关系到产品的质量、生产率及其加工产品的经济效益，生产规模的大小、工艺水平的高低以及解决各种工艺问题的方法和手段都要通过机械加工工艺来体现，因此工艺规程的编制的好坏是生产该产品的质量的重要保证的重要依据。在编制工艺时须保证其合理性、科学性、完善性。而机床夹具是为了保证产品的质量的同时提高生产的效率、改善工人的劳动强度、降低生产成本而在机床上用以装夹工件的一种装置，其作用是使工件相对于机床或刀具有个正确的位置，并在加工过程中保持这个位置不变。它们的研究对机械工业有着很重要的意义，因此在大批量生产中，常采用专用夹具。而本次对于拨叉加工工艺及夹具设计的主要任务是：1．完成拨叉零件加工工艺规程的制定；2．完成铣削切断的专用夹具设计。通过对拨叉零件的初步分析，了解其零件的主要特点，加工难易程度，主要加工面和加工粗、精基准，从而制定出拨叉加工工艺规程；对于专用夹具的设计，首先分析零件的加工工艺，选取定位基准，然后再根据切削力的大小、批量生产情况来选取夹紧方式，从而设计专用夹具。机床“羊角”拨叉加工工艺及孔加工夹具设计41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1.1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1张2．工艺过程卡片1套3．夹具装配图1张4．夹具体零件图1张5．说明书1份机床“羊角”拨叉加工工艺及孔加工夹具设计52零件工艺规程设计2.1产量的确定2.1.1生产类型的确定表2.1生产类型的划分生产类型同类零件的年产量/件重型零件（质量2000kg）中型零件（质量100～2000kg）小型零件（质量100kg）单件生产5以下10以下100以下成批生产小批生产5～10010～200100～500中批生产100～300200～500500～5000大批生产300～1000500～50005000～50000大量生产1000以上5000以上50000以上已知零件质量m约为2.2kg，由表2.1即可确定零件的生产性质。该零件的生产类型为小型零件大批量生产。2.1.2日生产量的确定零件的年产纲领（件/年）：N=2000件/年每台产品中该零件的数量（件/台）：n=1备品率：a=2%废品率：b=2%1．年产量Q=N×n×(1+a)×(1+b)=2081（件）2．年工作日D=365-1×52-7×2=299（天）3．日产量q=Q/D=7（件/天）通过计算可得知日该拨叉的日生产量为7件。机床“羊角”拨叉加工工艺及孔加工夹具设计62.2毛坯的选择及毛坯图的绘制2.2.1毛坯的选择按照零件图纸的设计要求，该零件毛坯的材料为HT200，毛坯种类为铸件。考虑到零件需加工表面少，精度要求不高，有强肋，且工作条件不差，既无交变载荷，又属于间歇工作，故选用金属型铸件，以满足不加工表面的粗糙度要求及生产要求。零件形状简单，因此毛坯形状需与零件的形状尽量接近，因内孔很小，所以无法铸出。毛坯选择的技术要求为：20D6孔与2-14D4孔中心线在水平方向的不平行度不大于0.1/150；20D6孔中心线对5D4钻槽不平行度不大于0.07/100；5D4钻槽对20D6孔中心线的偏移不大于0.08。2.2.2毛坯-零件综合图的绘制方法在选定毛坯和确定了毛坯的机械加工余量后，便可绘制毛坯-零件综合图。综合图的绘制方法是：1．以实线表示毛坯表面的轮廓、以点划线画出零件的轮廓；在剖面图上用交叉线表示加工余量，加工余量为3～5mm。2．标注毛坯尺寸和公差，毛坯的基本尺寸包括机械加工的余量在内，毛坯的尺寸公差参照有关资料。3．标注机械加工的粗基准符号和有关技术要求。毛坯尺寸是根据工艺规程，机械加工各工序的加工余量与毛坯制造方法能到的精度决定的，因此毛坯图绘制和工艺规程的制订是反复交叉进行的。根据以上绘制方法，用AutoCAD软件画出毛坯-零件综合图，如图2.1所示。2.3定位基准的分析与选择在制定零件加工工艺规程时，正确选择定位基准对保证加工表面的尺寸精度和相互位置精度的要求以及合理安排加工顺序都有重要的影响。机床“羊角”拨叉加工工艺及孔加工夹具设计7图2.1机床羊角拨叉零件毛坯图2.3.1基准的概念零件上用以确定其它点、线、面的位置所依据的那些点、线、面称为基准。根据其功用的不同，可分为设计基准、工艺基准两大类。在零件图上用以确定其它点、线、面的基准，称为设计基准。而零件在加工、测量、装配等工艺过程中使用的基准统称工艺基准。工艺基准又可分为：1．装配基准，在零件或部件装配时用以确定它在机器中相对位置的基准。2．测量基准，用以测量工件已加工表面所依据的基准。例如以内孔定位用百（千）分表测量外圆表面的径向跳动，则内孔就是测量外圆表面径