1、 I 摘要 本次毕业设计的是手扶拖拉机的副变速拨叉加工工艺及夹具设计。 手扶拖拉机的副变速机构，它由变速拨杆、变速杆、副变速拉杆、副变速拨杆、副变 速拨叉、副变速齿轮组成，变速杆外端连有变速手柄，副变速拉杆的内端连有副变速拨杆， 该副变速拨杆卡在副变速拨叉的凹槽内，副变速拨叉套装在副拨叉轴上，副变速拨叉的拨 爪卡在副变速齿轮的凹槽内，副变速齿轮和制动齿轮及轴承一同安装在副变速轴上。 通过此次设计，我再次学习了怎样制定工艺方案和夹具的设计，另外在此次设计中还 学到了如何确定毛坯的材料及毛坯的制造方式和涉及到的相关计算问题，让我对大学四年 的所学知识有机会全面系统的学习运用，为今后从事工作打下了良
2、好的基础。 关键词：副变速拨叉；工艺；夹具；设计 II Abstract This graduation design is the auxiliary gearbox of walking tractor forkprocessing technology and fixture design. Sub transmission mechanism of walking tractor, which is composed of a gear shift lever, the gear lever, auxiliary transmission rod, auxiliary transmis
3、sion lever, auxiliary transmission component fork, side gear,transmission rod is connected with the gear handle, auxiliary transmission of the inner end of the pull rod connected with the auxiliary gear shift lever, the secondary gear shift lever locking groove theauxiliary gear shift fork, side shi
4、ft fork is sheathed on the side fork shaft,finger side gear shift fork stuck in grooves in the side gears, side gearand brake gear and bearing were installed on a pair of transmission shaft. Through this design, I learned how to make again design process andfixture, also in this design but also lear
5、ned how to determine the manufacture material and blank blank and related computational issues involved, let me have the opportunity to learn to use four years of university knowledge systematically, for in the future work has laid a good foundation. Keywords: the secondary gear shifter; technology;
6、 fixture design; III 目录目录 摘要摘要 I I AbstractAbstract IIII 第第 1 1 章章 绪论绪论 - - 1 1 - - 1.1 机械加工工艺的意义 - 1 - 1.2 夹具制造的背景与意义 - 1 - 1.3 工艺及夹具的现状及发展趋势 - 2 - 第第 2 2 章章 副变速拨叉加工工艺规程设计副变速拨叉加工工艺规程设计 - - 4 4 - - 2.1 零件的分析 - 4 - 2.1.1 零件的作用 . - 4 - 2.1.2 零件的设计图样 . - 4 - 2.1.3 零件的工艺分析 . - 5 - 2.2 计算生产纲领，确定生产类型 - 5 - 2.3 选择毛坯的制造形式，绘制毛坯图 - 6 - 2.3.1 选择毛坯 . - 6 - 2.3.2 确定加工余量和毛坯尺寸 . - 7 - 2.3.3 铸件毛坯图 . - 8 - 2.4 工艺规程设计 - 8 - 2.4.1 定位基准的选择 . - 8 - 2.4.2 零件加工面加工方法的选择 . - 9 - 2.4.3 制订工艺路线 - 10 - 2.4.4 工艺方
