CA6440轻型客车变速器设计

摘要

变速器是汽车重要的传动系组成，在较大范围内改变汽车行驶速度的大小和汽车驱动轮上扭矩的大小。变速器能在发动机旋转方向不变的前提下，使汽车倒退行驶，而且利用挡位可以中断动力的传递。所以变速器的结构设计的合理性直接影响到汽车动力性和经济性。设计要求达到换挡迅速、省力、方便、有较高的工作效率、工作噪声低。

本次设计的是轻型客车变速器设计。它的布置方案采用中间轴式5+1挡和锁环式同步器换挡，并对倒挡齿轮和拨叉进行合理布置，其中一轴和第二轴的轴线在同一直线上。这种布置形式缩短了变速器轴向尺寸，在保证挡数不变的情况下，减少齿轮数目，从而使变速器结构更加紧凑。

首先利用已知参数确定变速器各挡传动比、中心矩，然后确定齿轮的模数、压力角、齿宽等参数。由中心矩确定箱体的长度、高度和中间轴及二轴的轴径，然后对中间轴和各挡齿轮进行校核，验证各部件选取的可靠性。最后绘制装配图及零件图。

设计结论表明，变速器齿轮及各轴尺寸确定，各轴强度的校核满足设计要求，设计结构合理。

关键词：客车；变速器；同步器

Abstract

The transmission gearbox, as an important part in automobile driving system is used to make up the shortcoming of engine torque and rotary speed. It can change the vehicle speed and type torque in a big scope, cut off the power transfer from the engine, and also provides a reverse traveling direction for the vehicle. Therefore, the reasonability of the structure design of a transmission gearbox directly affects the vehicle's dynamic performance. It is usually required shifting gears rapidly and conveniently, saving force, and having a higher working efficiency and low working noises.

This thesis designed a manual transmission gearbox of the Light bus. A scheme of structure with middle shafts, six (5+1) shifts and synchronizer was adopted here, Combine to pour to block wheel gear and stir fork to carry on a reasonable decoration .where the first and second shafts were arranged in line. This kind of structure reduces the gearbox dimension in the axis direction, in assurance block to count under the constant circumstance, decrease wheel gear number. Therefore makes the designed transmission gearbox more compact.

Using the given basic parameters, it was firstly determined the transmission ratio of each shift, the shaft center distances, the gear modulus, the gear pressing angles and widths, and so on. And then the general dimension of the gearbox, including its length, width and height. The stresses of the intermediate shaft and the gears were validated by using both the calculator and a self-made MATLAB program. Finally, some engineering drawings were carried out.

The calculated results show: the determined dimensions and stresses of the designed gears and shafts satisfied the design requirements; the adopted structure is reasonable.

Key words:Light; Transmission gearbox; Synchronizer

目录

第1章绪论 (1)

1.1 变速器的简介 (1)

1.2变速器的分类 (1)

1.3变速器的功用 (2)

1.4变速器的构成 (3)

第2章变速器设计方案及论证 (4)

2.1变速器的要求： (4)

2.2变速器设计方案论证 (4)

第3章各主要参数的设计计算 (7)

3.1传动比的确定 (7)

3.2中心距的初步确定 (7)

3.3变速器的外形尺寸 (8)

3.4轴的直径的初步确定 (8)

3.5齿轮参数设计 (8)

3.6各挡齿数的分配 (10)

3.6.1确定一挡齿轮的齿数 (11)

3.6.2二挡斜齿轮齿数的确定 (12)

3.6.3三挡齿轮齿数的确定 (12)

3.6.4五挡齿轮齿数的确定 (13)

3.6.5倒挡齿轮齿数的确定 (13)

3.7齿轮变位系数的确定 (13)

第4章变速器各挡齿轮的校核 (15)

4.1齿轮弯曲应力计算 (15)

4.1.1中间轴一挡直齿轮Z10校核 (15)

校核 (16)

4.1.2中间轴二挡斜齿轮Z

8

校核 (16)

4.1.3中间轴三挡斜齿轮Z

6

4.1.4中间轴四挡斜齿轮Z2校核 (16)

4.1.5中间轴五挡斜齿轮Z

校核 (16)

4

4.2齿轮接触应力计算 (17)

4.2.1 中间轴一挡直齿轮Z10校核 (17)