摘要

变速器用来改变发动机传到驱动轮上的转矩和转速，作用是在原地起步，爬坡，转弯，加速等各种行驶工况下，使汽车获得不同的牵引力和速度，同时使发动机在最有利工况范围内工作。变速器设有空挡和倒挡。需要时变速器还有动力输出功能。

因为变速箱在低档工作时有较大的力，所以一般变速箱的低档都布置靠近轴的后支承处，然后按照从低档到高档顺序布置各档位齿轮。这样做既能使轴有足够大的刚性，又能保证装配容易。变速箱整体结构刚性与轴和壳体的结构有关系。一般通过控制轴的长度即控制档数，来保证变速箱有足够的刚性。

本文设计研究了三轴式五挡手动变速器，对变速器的工作原理做了阐述，变速器的各挡齿轮和轴做了详细的设计计算，并进行了强度校核，对一些标准件进行了选型。变速器的传动方案设计。简单讲述了变速器中各部件材料的选择。

关键字 ：变速器；挡数；传动比；齿数；轴

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Abstract

Transmission to change the engine reached on the driving wheel torque and speed, is aimed at marking start, climbing, turning, accelerate various driving conditions, the car was different traction and speed Meanwhile engine in the most favorable working conditions within the scope of the work. And the trans mission in neutral gear with reverse gear. Transmission also need power output function.

Gearbox because of the low-grade work at a larger role, In general, the low-grade gearbox layout are close to the axis after support, Following from low-grade to high-grade order of the layout of stalls gear. This will not only allow axis are large enough for a rigid, but also ensures easy assembly. Gear box overall structure and rigid axle and the shell structure of relations. Generally

through the control shaft length control over several stalls to ensure that adequate gear box rigid.

This paper describes the design of three-axis five block manual trans

mission, the transmission principle of work elaborated, Transmission of the gear shaft and do a detailed design, and the intensity of a school. For some standard parts for the selection. Transmission Trans mission program design. A brief description of the trans mission of all components of the material choice.

Keywords： block; Transmission ratio; Teeth; Axis

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目录

摘要 ............................................................. I 第1章 绪论 ...................................................... 1 第2章 变速器传动机构布置 ....................................... 2

2.1 传动机构布置方案分析 .......................................................................... 2

2.1.1固定轴式变速器 ............................................................................ 2 2.1.2 倒挡布置方案 ............................................................................... 5 2.2零部件结构方案分析 ............................................................................... 6

2.2.1 齿轮形式 ....................................................................................... 6 2.2.2 换挡机构形式 ............................................................................... 6 2.2.3 变速器轴承 ................................................................................... 7

第3章 变速器主要参数的选择 ...................................... 9

3.1 中心距A .................................................................................................. 9 3.2齿轮参数的选取 ..................................................................................... 11

3.2.1 模数 ............................................................................................. 11 3.2.2 压力角? ..................................................................................... 11 3.2.3 螺旋角?的选取 ......................................................................... 12

3.2.4 齿宽b .......................................................................................... 12 3.2.5 齿轮变位系数的选择原则 ......................................................... 13 3.3 各挡齿轮齿数的分配及传动比的计算 ................................................ 13 3.3.1确定一档齿轮的齿数 .................................................................. 14

3.3.2确定常啮合齿轮副的齿数 .......................................................... 15 3.3.3确定其他档位的齿数 .................................................................. 16 3.3.4确定倒档齿轮的齿数 .................................................................. 16 3.4求各挡齿轮的变位系数并进行修正 ..................................................... 17 第4章 齿轮校核 ................................................. 21

4.1计算各轴的转矩 ..................................................................................... 22 4.2轮齿强度计算 ......................................................................................... 22

4.2.1直齿轮弯曲应力?w ..................................................................... 23 4.2.2斜齿轮弯曲应力?w ..................................................................... 24

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