变速器换挡叉铣叉脚外侧设计说明书讲义.doc

机械制造工艺 课程设计说明书 题目：变速器换挡叉叉脚外侧面铣夹具设计 目录 一、零件分析··················································3 1.1零件的作用············································3 1.2零件的工艺分析········································3 1.3尺寸和粗糙度的要求····································3 1.4位置公差要求···········································4 二、毛坯的设计··············································4 2.1选择毛坯··············································4 2.2确定机加工余量、毛坯尺寸和公差··························4 2.3 确定机械加工加工余量·································4 2.4 确定毛坯·············································5 2.5 确定毛坯尺寸公差·····································4 2.6设计毛坯图············································4 三、选择加工方法，拟定工艺路线································7 3.1基面的选择············································7 3.2粗基准的选择··········································8 3.3精基准的选择··········································14 3.4制定机械加工工艺路线··································15 四、加工设备及道具、夹具、量具的选择···························15 五、确定切削用量·············································18 六、基本时间的确定··········································20 七、夹具设计···············································25 八、总结·····················································29 一、零件分析 1.1零件的作用 题目所给定的零件是变速器换档叉（如下图2-1所示）孔套在轴上，并用M10×1-7H螺纹孔与轴定位，换挡叉脚卡在双联齿轮的轴中，变速操作机构通过换挡叉头部的操纵槽带动换挡叉与轴一起在变速箱中滑动，换挡叉脚拨动双联齿轮在花键轴上滑动，就可实现变速功能，从而实现变速器变速。换挡叉的主要工作面为操纵槽换挡叉脚两端面，主要配合面为孔，M10×1-7H螺纹孔和换挡叉脚侧面.该零件属于特殊形状零件，但复杂程度一般。由于换挡叉在工作是表面承受一定的压力，因此，要求有一定的强度和韧度。 1.2零件的工艺分析 由零件图可知，该零件的材料为35#钢，锻造成型，由零件的尺寸公差选择模锻加工成型，保证不加工表面达到要求的尺寸公差。 该零件需要加工的表面可大致分为以下四类： （1）Φ15.81的孔。 （2）以Φ15.81孔的轴心线为基准的上下两平面。 （3）两插口端面。 （4）两叉口内侧面。 （5）拔槽两个侧面。 （6）拨槽的内侧面面 （7）M10*1-7H的螺纹孔。 其中Φ15.8的孔以及叉口的上下端面和叉口的中间两侧面为主要的配合面，加工的精度及粗糙度的要求较高，应作为加工的重点 1.3尺寸和粗糙度的要求 Φ15.81的孔的上偏差为+0.043，下偏差为+0.016，配合公差为F8，属于间隙配合，孔的内表面的粗糙度为3.2，要求较高，鉴于孔径为15.81，可先采用Φ15.81的麻花钻钻孔，在用Φ10的立铣刀进行扩孔，最后用无心砂轮进行精加工。 Φ15.81的孔的上下两平面距离孔中心线的尺寸分别为11mm和12.7mm，上表面的粗糙度为6.3，下表面的粗糙度为12.5，直接采用立铣刀铣削加工即可达到要求。 以Φ15.81的孔的轴心线为基准的尺寸为9.65mm的两侧面的表面