CA6140车床的拨叉夹具毕业设计论文
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7参考文献···········································································································································17
1.零件分析
4．2．2切削力及夹紧力的计算·····································································································13
4．2．3定位误差分析·····················································································································15
3．1绘制零件图···································································································································11
3. 2编制工艺文件·································································································································11
2．5确定切削用量及基本工时············································································································6
3绘制零件图和编制工艺卡············································································································10
1.1零件的作用
题目所给的零件是CA6140车床的拨叉。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工作，获得所需的速度和扭矩的作用。零件上方的φ20孔与操纵机构相连，二下方的φ50半孔则是用于与所控制齿轮所在的轴接触。通过上方的力拨动下方的齿轮变速。两件零件铸为一体，加工时分开。
4夹具设计···········································································································································13
4．1问题的提出·································································································································13
（5）此外，还要考虑一些其它因素，如加Fra Baidu bibliotek表面物理机械性能的特殊要求，工件形状和重量等。
基面选择是工艺规程设计中的重要工作之一。基面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。否则，加工工艺过程中回问题百出，更有甚者，还会造成零件的大批报废，是生产无法正常进行。
2.2.1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φ20 mm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φ32mm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。
6致谢·····················································································································································16
2．2．1粗基准的选择······················································································································4
2．2．2精基准的选择······················································································································4
1、工艺路线方案一：
工序一：退火
工序二：粗、精铣Ф20 mm、Ф50 mm的下表面，保证其粗糙度为3.2 um
工序三：以Ф20 mm的下表面为精基准，粗、精铣Ф20 mm的孔的上表面，保证其粗糙度为3.2 um,其上、下表面尺寸为30mm，
工序四：以Ф20 mm的下表面为精基准，钻、扩、铰、精铰Ф20 mm的孔，保证其内表面粗糙度为1.6 um，垂直度误差不超过0.05mm
2.2.2精基准的选择。主要应该考虑基准重合的问题。当设计基准与工序基准不重合时，应该进行尺寸换算，这在以后还要专门计算，此处不再重复。
2..3制定工艺路线
制定工艺路线的出发点，应当是使零件的几何形状、尺寸精度及位置精度等技术要求能得到合理的保证。在生产纲领已确定为中批生产的条件下，可以考虑采用万能性机床配以专用夹具，并尽量使工序集中来提高生产率。除此以外，还应当考虑经济效果，以便使生产成本尽量下降。
工序五：以Ф20 mm的下表面为精基准，粗、半精镗Ф50 mm的孔，保证其内表面粗糙度为3.2 um
工序六；以Ф20 mm的下表面为精基准，粗、精铣Ф50 mm的上表面，保证其与孔的垂直度误差不超过0.07mm，其上、下表面尺寸为12mm
工序七：铣断
工序八：以Ф20 mm的孔为精基准，钻Ф8 mm的锥孔的一半Ф4 mm，装配时钻铰
4．2．4夹具设计及操作的简要说明·····························································································15
5结论·····················································································································································16
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，故选择铸件毛坯。
2.2基准面的选择
一个好的机构不但应该达到设计要求，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，要能保证加工的质量，同时是加工的劳动量最小。设计和工艺是密切相关的，又是相辅相成的。对于设计拨叉的加工工艺来说，应选择能够满足内花键加工精度要求的加工方法及设备。除了从加工精度和加工效率两方面考虑以外，也要适当考虑经济因素。在满足精度要求及生产率的条件下，应选择价格低的机床。
2．1毛坯的制造形式···························································································································3
2．2基准面的选择································································································································3
在选择各表面、内花键及槽的加工方法时，要综合考虑以下因素：
（1）要考虑加工表面的精度和表面质量要求，根据各加工表面的技术要求，选择加工方法及分几次加工。
（2）根据生产类型选择，在大批量生产中可专用的高效率的设备。在单件小批量生产中则常用通用设备和一般的加工方法。
（3）考虑被加工材料的性质。
（4）考虑工厂或车间的实际情况，同时也应考虑不断改进现有加工方法和设备，推广新技术，提高工艺水平。
1.2零件的工艺分析
CA6140车床共有两处加工表面，其间有一定位置要求。分述如下：
1.以φ20为中心的加工表面
这一组加工表面包括：φ20 的孔，以及其上下端面，上端面与孔有位置要求，孔壁上有一个装配时钻铰的锥孔，一个M8的螺纹孔。下端有一个47°的斜凸台。这三个都没有高的位置度要求。
2.以φ50为中心的加工表面
1零件的分析········································································································································2
1．1零件的作用····································································································································2
4．2夹具体设计·································································································································13
4．2．1定位基准的选择·················································································································13
2．3制定工艺路线································································································································4
2．4机械加工余量、工序尺寸及毛坯尺寸的确定············································································5
这一组加工表面包括：φ50 的孔，以及其上下两个端面。
这两组表面有一定的位置度要求,即φ50 的孔上下两个端面与φ20 的孔有垂直度要求。
由上面分析可知，加工时应先加工一组表面，再以这组加工后表面为基准加工另外一组。
2. 工艺规程设计
2.1毛坯的制造形式
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，故选择铸件毛坯。 图一毛坯图
1．2零件的工艺分析····························································································································2
2工艺规程的设计·······························································································································3
1.零件分析
4．2．2切削力及夹紧力的计算·····································································································13
4．2．3定位误差分析·····················································································································15
3．1绘制零件图···································································································································11
3. 2编制工艺文件·································································································································11
2．5确定切削用量及基本工时············································································································6
3绘制零件图和编制工艺卡············································································································10
1.1零件的作用
题目所给的零件是CA6140车床的拨叉。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工作，获得所需的速度和扭矩的作用。零件上方的φ20孔与操纵机构相连，二下方的φ50半孔则是用于与所控制齿轮所在的轴接触。通过上方的力拨动下方的齿轮变速。两件零件铸为一体，加工时分开。
4夹具设计···········································································································································13
4．1问题的提出·································································································································13
（5）此外，还要考虑一些其它因素，如加Fra Baidu bibliotek表面物理机械性能的特殊要求，工件形状和重量等。
基面选择是工艺规程设计中的重要工作之一。基面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。否则，加工工艺过程中回问题百出，更有甚者，还会造成零件的大批报废，是生产无法正常进行。
2.2.1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φ20 mm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φ32mm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。
6致谢·····················································································································································16
2．2．1粗基准的选择······················································································································4
2．2．2精基准的选择······················································································································4
1、工艺路线方案一：
工序一：退火
工序二：粗、精铣Ф20 mm、Ф50 mm的下表面，保证其粗糙度为3.2 um
工序三：以Ф20 mm的下表面为精基准，粗、精铣Ф20 mm的孔的上表面，保证其粗糙度为3.2 um,其上、下表面尺寸为30mm，
工序四：以Ф20 mm的下表面为精基准，钻、扩、铰、精铰Ф20 mm的孔，保证其内表面粗糙度为1.6 um，垂直度误差不超过0.05mm
2.2.2精基准的选择。主要应该考虑基准重合的问题。当设计基准与工序基准不重合时，应该进行尺寸换算，这在以后还要专门计算，此处不再重复。
2..3制定工艺路线
制定工艺路线的出发点，应当是使零件的几何形状、尺寸精度及位置精度等技术要求能得到合理的保证。在生产纲领已确定为中批生产的条件下，可以考虑采用万能性机床配以专用夹具，并尽量使工序集中来提高生产率。除此以外，还应当考虑经济效果，以便使生产成本尽量下降。
工序五：以Ф20 mm的下表面为精基准，粗、半精镗Ф50 mm的孔，保证其内表面粗糙度为3.2 um
工序六；以Ф20 mm的下表面为精基准，粗、精铣Ф50 mm的上表面，保证其与孔的垂直度误差不超过0.07mm，其上、下表面尺寸为12mm
工序七：铣断
工序八：以Ф20 mm的孔为精基准，钻Ф8 mm的锥孔的一半Ф4 mm，装配时钻铰
4．2．4夹具设计及操作的简要说明·····························································································15
5结论·····················································································································································16
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，故选择铸件毛坯。
2.2基准面的选择
一个好的机构不但应该达到设计要求，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，要能保证加工的质量，同时是加工的劳动量最小。设计和工艺是密切相关的，又是相辅相成的。对于设计拨叉的加工工艺来说，应选择能够满足内花键加工精度要求的加工方法及设备。除了从加工精度和加工效率两方面考虑以外，也要适当考虑经济因素。在满足精度要求及生产率的条件下，应选择价格低的机床。
2．1毛坯的制造形式···························································································································3
2．2基准面的选择································································································································3
在选择各表面、内花键及槽的加工方法时，要综合考虑以下因素：
（1）要考虑加工表面的精度和表面质量要求，根据各加工表面的技术要求，选择加工方法及分几次加工。
（2）根据生产类型选择，在大批量生产中可专用的高效率的设备。在单件小批量生产中则常用通用设备和一般的加工方法。
（3）考虑被加工材料的性质。
（4）考虑工厂或车间的实际情况，同时也应考虑不断改进现有加工方法和设备，推广新技术，提高工艺水平。
1.2零件的工艺分析
CA6140车床共有两处加工表面，其间有一定位置要求。分述如下：
1.以φ20为中心的加工表面
这一组加工表面包括：φ20 的孔，以及其上下端面，上端面与孔有位置要求，孔壁上有一个装配时钻铰的锥孔，一个M8的螺纹孔。下端有一个47°的斜凸台。这三个都没有高的位置度要求。
2.以φ50为中心的加工表面
1零件的分析········································································································································2
1．1零件的作用····································································································································2
4．2夹具体设计·································································································································13
4．2．1定位基准的选择·················································································································13
2．3制定工艺路线································································································································4
2．4机械加工余量、工序尺寸及毛坯尺寸的确定············································································5
这一组加工表面包括：φ50 的孔，以及其上下两个端面。
这两组表面有一定的位置度要求,即φ50 的孔上下两个端面与φ20 的孔有垂直度要求。
由上面分析可知，加工时应先加工一组表面，再以这组加工后表面为基准加工另外一组。
2. 工艺规程设计
2.1毛坯的制造形式
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，故选择铸件毛坯。 图一毛坯图
1．2零件的工艺分析····························································································································2
2工艺规程的设计·······························································································································3