论文总字数：23079字

摘 要

基于目前变速器需要更新换代的情况，本文主要对轻型客车变速器进行三维整体设计，根据三维扫描获取的点云数据在CATIA中进行变速器的全参数建模和虚拟装配，并完成二维工程图设计。主要的内容为：

首先以逆向工程思想为基础，使用Handy Scan 3D三维激光扫描仪获取了变速器各个零部件的点云数据，对点云数据进行了预处理，掌握了激光数字扫描法。从点云数据出发在CATIA环境中对变速器各个零件进行了重构和三维实体化。研究利用CATIA建立三维模型的基本方法和原理。

然后对变速器总成各个零件的装配位置、顺序和零件间的约束关系进行了分析，在CATIA环境中按从内到外的顺序完成了变速器总成的装配设计，对建模过程中出现的问题进行了修改，分析了齿轮啮合装配的方法。研究在CATIA中进行装配设计的思路和方法。

最后根据任务书中的轻型客车整车数据以及变速器设计要求，利用经典计算公式，完成了变速器的整体设计工作，进行了可行性分析。通过变速器总装图的二维工程图设计，对轴承内外圈的配合尺寸进行了选用。以第二轴总成和一档齿轮为例说明了变速器关键部件的二维工程图设计过程，对第二轴的尺寸公差、表面粗糙度、形位公差进行了选用。研究在CATIA和AutoCAD中进行二维图设计的方法和步骤。

通过轻型客车变速器总成的三维设计，从逆向建模、装配到工程图设计系统地进行了研究，完成了变速器总成的整体设计。积累了宝贵的经验，为后续机械部分的开发奠定了基础。

关键词：变速器 逆向工程 装配 工程图设计 CATIA

Three-dimensional design of transmission assembly for light passenger car

Abstract

Based on the current situation that the transmission needs to be replaced, this thesis mainly designs the three-dimensional overall design of the light passenger car transmission. Based on the point cloud data obtained by the three-dimensional scanning, the full-parameter modeling and virtual assembly of the transmission are performed in CATIA, and the two-dimensional engineering drawing design is completed. The main contents are:

First, based on the idea of reverse engineering, a 3D laser scanner was used to acquire point cloud data for different transmission components, the point cloud data was preprocessed, and the laser digital scanning method was mastered. Starting from the point cloud data, the various parts of the transmission are reconstructed and three-dimensionalized in the CATIA environment. Learn basic methods and principles for building 3D models using CATIA.

Then the aggregation location, the sequence of each part of the transmission group, and the relationship relationships between the parts are analyzed. In the CATIA environment, the assembly design of the transmission assembly was completed from the inside to the outside. Modifications were made and the method of gear mesh assembly was analyzed. Study the ideas and methods of assembly design in CATIA.

Finally, according to the light vehicle data in the task book and the transmission design requirements, the classic design formula is used to complete the overall design of the transmission and the feasibility analysis is carried out. Through the design of the two-dimensional engineering drawing of the assembly drawing of the transmission, the matching dimensions of the inner and outer rings of the bearing are selected. Taking the second shaft assembly and the first gear as an example, the design process of the two-dimensional engineering drawings of the key components of the transmission is explained, and the dimensional tolerance, surface roughness, shape and position tolerance of the second shaft are selected. Study the methods and steps of designing two-dimensional drawings in CATIA and AutoCAD.

Through the three-dimensional design of the light-duty passenger car transmission assembly, systematic research was conducted from reverse modeling, assembly to engineering drawing design, and the overall design of the transmission assembly was completed. We have accumulated valuable experience and laid the foundation for the further development of the mechanical parts.

Key Words：transmission; Reverse Engineering; assembly; Engineering drawing design ;CATIA

目 录

摘要 I

Abstract II

第一章 绪论 1

1.1研究背景和意义 1

1.2国内外变速器产品研究现状 1

1.2.1自动变速器的研究现状 2

1.2.2手动变速器的研究现状 3

1.3课题的主要研究内容 3

第二章 基于CATIA软件的三维建模 5

2.1 CATIA软件简介 5

2.2逆向工程 5

2.2.1逆向工程概述 5

2.2.2变速器点云数据获取 5

2.2.3变速器点云数据预处理 6

2.3变速器总成三维建模 8

2.3.1变速器外壳 8

2.3.2关键部件 14

2.3.3其他零件 15

2.4本章小结 19

第三章 基于CATIA软件的装配设计 20

3.1 CATIA装配设计介绍 20

3.2变速器总成装配设计 20

3.3本章小结 23

第四章 二维工程图设计 24

4.1变速器总成总装图设计 24

4.1.1平面视图的获取 24

4.1.2尺寸标注和技术要求 26

4.1.2零件序号和明细栏 27

4.2变速器关键部件零件图设计 28

4.2.1第二轴总成 28

4.2.2一档齿轮 33

4.3本章小结 34

第五章 总结与展望 35

参考文献 36

致谢 38

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