大连理工大学网络教育学院
本 科 生 毕 业 论 文（设 计）
题 目：车床C6140A支架机械加工工艺及夹具设计
层 次： 专科起点本科
专 业： 机械设计制造及其自动化
年 级： 年 季
学 号：
学 生：
指导教师：
完成日期： 2022年5月29日
本论文应用本专业所学课程的理论和实际知识进行一次夹具设计工作的实际训练，本设计的内容是以大连机床集团设计生产的C6140A普通车床为设计原型，
经过学习和钻研，对C6140A普通车床的机械加工工艺方案的分析和设计。
支架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床中，主要对各种机床起到支撑，辅助加工的作用。该零件的结构虽然不太复杂，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C6140A普通车床支架的加工工艺，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，就工序钻扩铰B、C、D孔设计夹具，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
目 录
内容摘要·············································································· I
引 言··············································································· 1
1 概述··············································································· 2
2 设计任务说明···································································· 4
2.1 零件的作用···································································· 4
2.2·············································································· 零件的工艺分析 4
3 工艺路线的制定································································· 7
3.1 工艺路线的拟订······························································· 7
3.1.1年产量和批量的确定······················································· 7
3.1.2确定毛坯的制造形式······················································· 7
3.1.3基准的选择··································································· 7
3.1.4具体分析······································································ 8
3.1.5工艺路线的拟订····························································· 9
3.2 确定毛坯的制造形式······················································· 10
3.3 基准的选择··································································· 10
3.4 具体分析······································································ 11
3.5 工艺路线的拟订····························································· 11
3.6 工艺卡的填写································································ 13
3.7.1工序编排及相关计算······················································ 14
3.7.2工艺设计的整体评估计算················································ 19
4 夹具的设计····································································· 22
4.1 工序夹具的确定····························································· 22
4.1.1 夹具概述···································································· 22
4.1.2 机床夹具的作用··························································· 22
4.1.3 机床夹具的功能··························································· 23
4.1.4 机床夹具在机械加工中的作用·········································· 23
4.2 夹具设计有关计算·························································· 24
4.2.1 定位基准的选择··························································· 24
4.2.2 切削力及夹紧力计算····················································· 24
4.2.3 定位误差分析······························································ 25
4.3 夹具装配······································································ 26
4.3.1 局部装配···································································· 26
4.3.2 整体装配···································································· 26
4.4 夹具经济性分析····························································· 26
结论·················································································· 28
参考文献············································································ 29
本篇论文中，主要是介绍了我这次设计的主要设计思路及设计过程。我的设计课题是CD6140A支架机械加工工艺及夹具设计。设计的主要内容有：绘制零件图、设计夹具、刀具、量具等。此次设计，综合运用了本专业的各方面的专业知识，如《机械制图》、《机械制造工艺学》、《机床夹具设计》《机械设计工艺学》等，在这整个设计过程中进一步加深并巩固了我这几年所学的知识，令我感到受益匪浅，收获颇丰。
本车床具有广泛用途，主要用于各种回转零件的外圆、内孔、端面、锥度、切槽及公制螺纹、模数螺纹、径节螺纹等的车削加工，此外还可以用来进行钻孔、铰孔、套料、扩孔、滚花、拉油槽等加工。本系列车床刚性强，适合于使用硬质合金刀具对各种黑色金属和有色金属进行强切削和高速切削。本系列车床加工精度可达IT7级（按GB1800-79），加工表面粗糙可达2.5。本系列车床性能好、操作方便、美观宜人。本系列车床有各种不同配置、供用户选购。如：公制或英制大丝杠、公制或英制刻度、快速螺纹锁紧或凸轮锁紧主轴头，左手轮或右手轮溜板箱，以及不同的电源、电压、频率等。
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
普通车床是由人工操纵能对轴、盘、环等多种类型工件进行多种工序加工的卧式车床。常用于加工工件的内外回转表面、端面和内外各种螺纹，采用相应的刀具和附件，还可以进行钻孔，扩孔攻丝和滚花等。主轴由电机经主轴箱带动旋转，工件装在主轴卡盘中或支承在顶尖间并随主轴旋转，旋转运动经进给箱、丝杠或光杠传至溜板箱，转变为刀架的进给运动。丝杠是为车削螺纹时使刀架获得精确的移动量而设置的。普通车床没有交换齿轮和螺纹种类变换机构，适当选择传动比可用于加工公制、英制、模数和径节等种螺纹。按需要方向刀架可以纵横向进给，能同时安装４把刀具，可按需要选用。尾座的功用是用后顶尖支承轴类工件，或用于安装孔类加工刀具。普通车床是应用最广泛的一种车床，万能性强，约占车长类机床总台数的60%。
本拨叉零件从加工至成品，需完成从毛坯选择开始，编排工艺，工装夹具设计以及对该产品的说明书的编写。
图1.1 C6140A车床
本次设计任务如下：
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
该零件来自C620车床的三杠支架，它位于车床的尾部主要作用是支承丝杠，光杠和操纵杆，相应的孔位要同轴和平行，使溜板箱纵向移动无阻尼现象，保证加工的精度。
这篇文章既然说到了C6140A车床，我在这里简要介绍一下这个车床。卧式车床它的加工对象广，主轴转速和进给量的调整范围大，能加工工件的内外表面、端面和内外螺纹。这种车床主要由工人手工操作，生产效率低，适用于单件、小批生产和修配车间。C6140A指的是最大切削直径为400mm的卧式车床。
该零件来自CD6140A车床的三杠支架，它位于车床的尾部主要作用是支承丝杠，光杠和操纵杆，相应的孔位要同轴和平行，使溜板箱纵向移动无阻尼现象，保证加工的精度。
图2.1 C6140A车床的三杠支架
支架共有5组加工表面（如1.3图），它们相互间有一定的位置要求。现分析如下：
1、以B孔（Φ25.8H12）为基准的加工孔。这一组加工表面包括：B(Φ25.8H12,Ra为6.3μm）、C(Φ30H7,Ra为1.6μm）和D(Φ55H7,Ra为1.6μm）的孔。
2、A面（226×72,Ra为1.6μm）。
3、I（两个Φ20的螺钉孔，Ra为12.5μm）和J、M（两个Φ10的销孔，Ra为1.6μm）。
4、M6螺纹孔和O孔(Φ6油孔，Ra为12.5μm)。
5、E面（M6螺钉孔和Φ6油孔所在平面，Ra为12.5μm）。
图2.2 支架加工表面示意图
这几组加工表面之间有一定的位置要求，主要是：
1、C孔（Φ30H7）和B孔（Φ25.8H12）两孔的平行度公差为100：0.08；
2、D孔(Φ55H7)和B孔（Φ25.8H12）两孔的平行度公差为100：0.08;
C孔(Φ30H7)孔和A面(72×226)的平行度公差为100：0.07；D孔(Φ55H7)孔和A面(72×226)的平行度公差为100：0.07。
由以上分析可知，可以先加工平面，然后借助于专用夹具同时加工三个孔，保证它们之间的位置精度要求。
图2.3 车床支架技术要求
根据各面的加工精度与表面粗糙度确定其加工次数。加工精度要求较高的表
面宜将工艺过程划分为粗、半精、精三个加工阶段;根据加工表面的形状、尺寸及生产批量选择其加工方法。现分析如下：
1、A面：L×B=226×72mm,Ra为1.6μm;粗铣--半精铣--精铣
2、B孔：Φ25.8H12,Ra为6.3μm；钻--扩
3、C孔：Φ30H7,Ra为1.6μm:钻--扩--铰
4、D孔：Φ55H7,Ra为1.6μm；钻--扩--铰
5、E面：Ra为12.5μm；粗铣
6、F面：Ra为12.5μm；粗铣
7、H面：Ra为12.5μm；粗铣
8、I、K孔：Ra为12.5μm；钻--锪
9、M孔：Ra为1.6μm；钻--扩--铰
10、N孔：Ra为12.5μm；钻—攻丝
11、O孔,Ra为12.5μm；钻
零件有两个主要的加工表面，分别零件底面和一个侧面，这两个主要的加工
表面之间有一定的位置要求，现分析如下：
1.零件底面：
这一加工表面主要是平面的铣削，它为后来的加工定位。
