2014机械制造技术基础课程设计.docVIP

机械制造技术基础课程设计 说明书 设计题目：零件的机械加工工艺规程设计及夹具设计 学生姓名：郭强 学号：0914112105 专 业：机械设计制造及其自动化 指导老师： 晋中学院 2012年6月3日 目 录 零件的分析··········································································· 零件的作用··········································································· 零件的工艺分析··································································· 工艺规程的设计········································································ 毛坯的制造形式······································································· 基准面的选择··········································································· 粗基准的选择··········································································· 精基准的选择··········································································· 制定的工艺路线··········································································· 机械加工余量、工序尺寸及毛坯尺寸的确定··························· 确定切削用量及基本工时··························································· 绘制零件图和编制工艺卡··························································· 夹具设计 ··········································································· 夹具设计任务 ··········································································· 绘制夹具装配图 ··········································································· 1.零件分析 1.1 零件的作用 题所给的是CA6140车床上的拨叉，它位于车床变速机构中，主要起换挡作用，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。零件上方的Φ20mm的孔与操作机构相连，下方的Ф50mm的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，两零件铸造为一体，加工时分开。 1.2 零件的工艺分析 CA6140车床上的拨叉共有两处加工表面。其间有一定的位置要求，分述如下： 1.2.1 以Ф20mm为中心的加工表面 这一组加工表面包括：Ф20mm的孔，以及其上下表面，孔壁上有一个装配时要钻铰的Ф8mm的锥孔，一个M6的螺纹孔，和一个缺口。 1.2.2 以Ф50mm为中心的加工表面 这一组加工表面包括：Ф50mm的孔，以及其上、下端面； 这两组表面有一定的位置要求； Ф50mm的孔的上、下表面与Ф20的孔的垂直度误差为0.07mm。 Ф20mm的孔的上、下表面与Ф20的孔的垂直度误差为0.05mm。 Ф50mm、Ф20mm的孔的上、下表面以及Ф50mm的孔的内表面的粗糙度误差为3.2um。 Ф20mm的孔的内表面的粗糙度误差为1.6um，精度为IT7。 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，故选择铸造毛坯。图一 毛坯图 2.2 基准面的选择 2.2.1 粗基准的选择 对零件而言，尽可能选择不加工表面为粗基准，而对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，根据这个基准原则，