75拖拉机变速箱机械加工工艺规程设计
本科毕业设计（论文）
题 目 75拖拉机变速箱壳体机械加工工艺规程设计 姓 名 XXXXXX 班 级 机械设计制造及其自动化（本科二班） 学 号 2009330 院 （系） 机械工程学院 指导教师 李 明
郑州科技学院机械工程系
二○一三年五月二十日
75拖拉机变速箱机械加工工艺规程设计
75拖拉机变速箱壳体工艺规程设计
摘 要
机械制造业是一个国家技术进步和社会发展的支柱产业之一，无论是传统产业，还
是新兴产业，都离不开各式各样的机械设备。这次毕业设计就是选择了这样一个课题——75拖拉机变速箱体机械加工工艺规程设计。使生产对象（原材料，毛坯，零件或总成等）的质和量的状态发生直接变化的过程叫工艺过程，如毛坯制造，机械加工，热处理，装配等都称之为工艺过程。在机加工工艺编制方面，主要通过仔细分析产品零件图和相关技术要求，查阅箱体类零件相关资料，结合暑假实习经历等等，考虑了的工艺结构要求、批量要求、经济性、可行性等多方面因素，最终安排了19个工序来完成变速箱体的加工，其中包括各道工序的加工方法，机床、刀具、辅具、量具的选择，基准面的选取，定位和夹紧方案的拟定。
关键字：变速箱体 工艺路线 工序
I
Abstract
Design of technics processes for the gearbox casing of 75
tractor
ABSTRACT
Machinery manufacturing is one of the pillar industries which show a nation’s development of technology and society. Both traditional and burgeoning industries can’t be separated from verities of mechanical equipment. This disquisition had just selected such a task—to study the machining craft and the fixture for heavy boring shafting bearing holes of Dongfanghong tractor.Make the state of quality and quantity of objects (such as raw materials, semifinished product, component or assembly) changes directly in the process is called craft process, such as blank manufacturing, machining, heat treatment, assembly and so on all is called process. In the aspect of machining craft, part drawing and the technological request were thought over， with the help of some information about the machining craft of parts such as boxes it is arranged to produce the part in eighteen steps which include the information on what means to use，which machine tools, what fixtures, assist tools and measure tools needed in each step. Then selected datum plane for each step, studied out orientation and clamping scheme for each step. in the aspect of fixture designing, I had designed a set of fixture for the heavy boring of the shafting bearing holes. After some analyzing and calculating.
Keyword: Gearbox casing, Technics process, Working procedure
II
75拖拉机变速箱机械加工工艺规程设计
目 录
摘 要 ............................................................................................................................................................ I ABSTRACT ............................................................................................................................................. II 1.绪论 ......................................................................................................................................................... 1
1.1 机械制造行业的地位和发展 .................................................................................................. 1 1.2设计的选题意义 .......................................................................................................................... 1 1.3 设计的主要内容和目的 ........................................................................................................... 2 1.4 本章小结 ...................................................................................................................................... 2
2.零件的工艺分析 ............................................................................................................................... 3
2.1 零件的作用.................................................................................................................................. 3 2.2 零件的工艺分析 ........................................................................................................................ 3 2.3技术要求 ....................................................................................................................................... 3 2.4 计算生产纲领 ............................................................................................................................. 4 2.5 计算生产节拍 ............................................................................................................................. 4
3 毛坯的选择 ......................................................................................................................................... 4
3.1确定毛坯的制造形式 ................................................................................................................ 4 3.2毛坯的选择 ................................................................................................................................... 4 3.3 毛坯的尺寸和公差 .................................................................................................................... 4 3.4确定机械加工余量 ..................................................................................................................... 6 3.5 毛坯图的绘制 ............................................................................................................................. 7
4.工艺规程设计 .................................................................................................................................... 8
4.1 工艺路线的安排 .................................................................................................................. 8
4.1.1 工件的时效处理 ............................................................................................................ 8 4.1.2 安排加工工艺的顺序时应先面后孔 ........................................................................ 8 4.1.3、粗、精加工阶段要分开 ............................................................................................ 8
4.2基准的选择.............................................................................................................................. 8
4.2.1粗基准的选择 .................................................................................................................. 8 4.2.2 精基准的选择 ................................................................................................................ 9
4.3 制定工艺路线 ....................................................................................................................... 9 5.工序的切削用量及工时的确定 ............................................................................................. 11
5.1 工序20：铣四个定位平面 ................................................................................................... 11
III