变速箱拨叉中批生产工艺规程判定与工装设计

网络教育学院本科生毕业论文（设计）题目：变速箱拨叉中批生产工艺规程判定与工装设计学习中心：重庆酉阳奥鹏学习中心层次：专科起点本科专业：机械设计制造及其自动化年级：2010年秋季学号：101186411522学生：冉捷文指导教师：王爽完成日期：2012年09月08日大连理工大学网络教育学院毕业论文（设计）I内容摘要本文详细阐述了“拨叉”生产工艺的判定与铣断夹具的设计论证过程。拨叉类零件以其良好的操纵性和良好的稳定性广泛应用于各种机械的变速箱中，该零件的制造工艺简单，但其过程涉及了机械加工工艺的很多方面，是机械加工的基础的体现。本文详细分析了该零件从毛坯选择到加工为成品的过程。就拨叉的加工工艺，分析了两套加工方案，最终确定了一套科学合理的加工路线，并在以后的计算过程中，验证了这套工序的科学性，数字分析表明，该工序制定比较合理。最后，就工序Ⅸ设计夹具，并做了切削力、夹紧力的分析。关键词：机械加工；工艺；切削；夹具设计；工时变速箱拨叉中批生产工艺规程判定与工装设计II目录内容摘要·····························································································I引言·······························································································11概述·································································································21.1给定零件···················································································21.2设计任务···················································································32零件工艺分析··················································································42.1零件的作用、材料、形状特征······················································42.2技术要求·················································································42.3设计基准·················································································52.3.1粗基准的选择···································································52.3.2精基准的选择···································································53工艺过程设计··················································································63.1毛坯—零件综合图设计·······························································63.2工序判定·················································································73.3填写工艺卡··············································································94典型工装设计················································································154.1定位原理及方案分析································································154.2夹具总体设计·········································································154.3夹具体设计············································································16结论·································································································17参考文献···························································································18附图······························································································19变速箱拨叉中批生产工艺规程判定与工装设计III·······································································································19附图1变速箱拔叉毛坯零件综合图·························································19变速箱拨叉中批生产工艺规程判定与工装设计IV·······································································································20变速箱拨叉中批生产工艺规程判定与工装设计1引言在些次设计中我们主要是设计CA6140拨叉的铣床夹具。题目所给定的零件为拨叉，是一种辅助零件，它位于车床变速机构中，主要起换档，使主轴回转运动按照工作者的要求进行工作本次设计共分为五部分，分别是：①绘制、分析零件图，进行工艺审查；②选择毛坯制造方式，画毛坯图；③拟订工艺路线，确定加工工序；④机床夹具总体方案设计。通过机床工艺及夹具设计，汇总所学专业知识如一体(如《公差于配合》、《机械零件设计》、《金属切削机床》、《机械制造工艺》等)。让我们对所学的专业课得以巩固、复习及实用，在理论与实践上有机结合；使我们对各科的作用更加深刻的熟悉与理解，并为以后的实际工作奠定坚实的基础！变速箱拨叉中批生产工艺规程判定与工装设计21概述拨叉类零件以其良好的操纵性和良好的稳定性广泛应用于各种机械的变速箱中，该零件的制造工艺简单，但其过程涉及了机械加工工艺的很多方面，是机械加工的基础的体现，本文将对该类零件的加工工程进行一次全面的阐述。1.1给定零件一、件图分析图1-1变速箱拔叉零件图原图拔叉形式如上图所示，本文将对图中所绘制的拔叉进行具体的件图分析。二、生产类型已知此拨叉零件的生产类型为大批量生产，所以初步确定工艺安排为：加工过程划分阶段；工序应当集中；加工设备以通用设备为主，大量采用专用工装。三、加工设备1）机床的选择：X6022型卧式铣床，X5028立式铣床，Z535立式钻床，T618卧式镗床2）采用专用夹具。3）采用硬质合金铣刀，铰刀。4）采用极限量规。变速箱拨叉中批生产工艺规程判定与工装设计35）其他：对垂直度误差采用千分表进行检测，对角度尺寸利用专用夹具保证，其他尺寸采用通用量具即可。在加工此拔叉零件时，需要设计镗孔夹具、铣槽夹具及钻顶面螺纹底孔夹具各一套。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．夹具装配图1张3．说明书1份变速箱拨叉中批生产工艺规程判定与工装设计42零件工艺分析2.1零件的作用、材料、形状特征1.1.1零件的作用CA6140车床的拨叉，位于车床变速机构中，主要起换档作用，使主轴回转运动按照所需的速度和扭矩工作。通过拨叉可以控制滑套与旋转齿轮的接合，在滑套的上面有凸块，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，从而将动力传至输出轴。因此，摆动拨叉可以控制滑套与不同齿轮的结合与分离，以达到换档的目的。1.1.2零件的工艺分析零件的材料为HT200，灰铸铁属于脆性材料，故不能锻造和冲压。但灰铸铁的铸造性能和切削加工性能优良。以下是拨叉需要加工的表面以及加工表面之间的位置要求：1）中心圆孔0.021035mm。2）小头孔内部为0.021020四齿方花键孔，花键底孔有2*15°的倒角。3）键槽0.11015与中心孔有0.03的垂直度，深为0.15052。先加工拨叉中心孔，然后以此作为基准采用专用夹具进行加工，并且保证位置精度要求。再根据各加工方法的经济精度及机床所能达到的位置精度，并且此拨叉零件没有复杂的加工曲面，采用常规的加工工艺均可保证。2.2技术要求一个好的结构不但要应该达到设计要求，而且要有好的机械加工工艺性，也就是要有加工的可能性，要便于加工，要能够保证加工质量，同时使加工的劳动量最小。而设计和工艺是密切相关的，又是相辅相成的。设计者要考虑加工工艺问题。工艺师要考虑如何从工艺上保证设计的要求。其加工有四组加工：177H内花键孔；粗精铣上端面；粗精铣18H11底槽；钻、铰2-M8通孔，并攻丝。（1）以2012H为主要加工面，拉内花键槽177H，槽数为4个，其粗糙度要求是底边6.1Ra，侧边3.2Ra，2212H内孔粗糙度6.3Ra。（2）另一组加工是粗精铣上端面，表面粗糙度要求为3.2Ra。（3）第三组为粗精铣18H11底槽，该槽的表面粗糙度要求是两槽边3.2Ra，槽底的表面粗糙度要求是3.6Ra。变速箱拨叉中批生产工艺规程判定与工装设计5（4）钻并攻丝2-M8。2.3设计基准定位基准的选择是工艺规程设计中的重要工作之一，定位基准选择得正确与合理，可以使加工质量得到保证，生产率得以提高。机械加工工序安排为先基准后其他，先面后孔，先主后次，先粗后精，根据以上原则，拟订基准。2.3.1粗基准的选择对于零件而言，尽可能选择不加工表面为粗基准。而对有若干个不加工表面的工件，则应以与加工表面要求相对位置精度较高的不加工表面作粗基准。根据这个基准选择原则，现选取φ26孔的不加工外轮廓表面作为粗基准，利用一组共两块V形块支承这两个φ35作主要定位面，限制5个自由度，再以一个销钉限制最后1个自由度，达到完全定位,然后进行铣削。2.3.2精基准的选择根据“基准统一”的原则，为保证定位基准和工序基准相重合，应以零件的右端面和花键孔中心线为精基准。变速箱拨叉中批生产工艺规程判定与工装设计63工艺过程设计3.1毛坯—零件综合图设计一、毛坯的选择零件材料为HT200。考虑零件在机床运行过程中所受冲击不大，零件结构又比较简单，生产类型为中批生产，故选择砂型机器造型铸件毛坯。查《机械制造工艺设计简明手册》第41页表2.2-5,选用铸件尺寸公差等级为CT-8。二、造型方法及加工余量：（1）毛坯余量的确定①总体分析通过分析零件图纸（图1-1），零件的两小孔、大孔及上下端面需要机加工才