机械5

摘要 本次设计是汽车变速箱箱体零件的加工工艺规程及一些工序的专用夹具设计。汽车变速箱箱体零件的主要加工表面是平面及孔系。保证平面的加工精度要比保证孔系的加工精度容易。因此，本设计遵循先面后孔的原则。并将孔与平面的加工明确的划分为粗加工和精加工阶段，以保证孔系的加工精度。基准选择以变速箱箱体的输入轴与输出轴的支承孔作为粗基准，以顶面与两个工艺孔作为精基准。主要加工工序安排先以支承孔系定位加工出上表面。再以顶平面与支承孔系定位加工出孔。整个加工过程均选用组合机床，夹具选用专用夹具夹紧。加紧方式多选用手动夹紧，夹紧可靠。 本设计要求“以质量求发展，以效益求生存”，在保证零件加工质量的前提下，提高了生产率，降低了生产成本，是国内外现代机械加工工艺的主要发展方面方向之一。通过对变速箱体零件图的分析及结构形式的了解，从而对变速箱体进行工艺分析、工艺说明及加工过程的技术要求和精度分析。然后再对变速箱体的底孔、轴承孔的加工进行夹具设计与精度和误差分析，该工艺与夹具设计结果能应用于生产要求。 关键词：变速箱；加工工艺；定位；夹紧；夹具设计 Abstract This desig
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ng force 目录 摘要1 Abstract 2 第1章绪论5 1.1选题背景5 1.2选题的目的及意义5 1.3、国内外发展现状5 1.4设计的主要内容7 第2章变速箱体加工工艺规程设计4 2.1零件的分析4 2.1.1零件的作用4 2.1.2变速箱体的结构特点4 2.2变速箱体的工艺性5 2.2.1零件的工艺分析5 2.2.2箱体的材料、毛坯及热处理5 2.2.3毛坯的材料热处理6 2.2.4确定毛坯的制造形式6 2.2.5基面的选择6 2.2.6确定工艺路线7 2.2.7机械加工余量、工序尺寸及毛坯尺寸的确定8 2 .箱体9 (1)主要平面加工的工序尺寸及加工余量9 2.2.8确定切削用量9 2.3本章小结20 第3章铣箱体上平面夹具设计21 3.1铣夹具简图21 3.2定位基准的选择21 3.3定位元件的设计21 3.4定位误差分析22 3.5铣削力与夹紧力计算22 3.6夹具体槽形与计对刀装置设23 3.7夹紧装置及夹具体设计25 3.8夹具设计及操作的简要说明26 3.9本章小结26 第4章专用刀具选择28 4.1刀具选择28 4.1.1刀具材料选择28 4.1.2确定合理的切削方式及工作角度29 4.1.3妥善解决刀具的排屑，容屑，断屑问题29 4.1.4合理的确定刀具的结构参数29 4.1.5正确选择刀具的轮廓30 4.2专用量具选择30 4.2.1量规工作尺寸的确定30 4.2.2量规的技术要求31 4.3本章小结31 结论32 参考文献33 致谢34