摘  要
 
本设计的任务是设计一台用于货车上的手动变速器。本设计采用中间轴式变速器.
根据轿车的外形、轮距、轴距、最小离地间隙、最小转弯半径、车辆重量、满载重量以及最高车速等参数,结合自己选择的适合于该货车的发动机型号可以得出发动机的最大功率、最大扭矩、排量等重要的参数。再结合某些货车的基本参数，选择适当的主减速比。
    本次设计的汽车变速箱主要是从强度方面来对齿轮的尺寸计算及校核，轴的尺寸计算和位置的确定，选择设计满足其承载能力的同步器。另外，针对齿轮作用力的不同，在不同的轴上选择合适的轴承。利用软件Pro/e和CAD完成变速器总成图、第一轴、第二轴、中间轴、各个挡齿轮及同步器的设计。
 
关键词：变速器；锁环式同步器；传动比；中间轴；货车
 
 
 
 
 
 
 
 
 
 
 
 
 

 
ABSTRACT
 
The duty of this design is to design a manual transmission used in the truck, It’s the countershaft-type transmission gearbox.
According to the contour, track，wheel base，the smallest ground clearance, the smallest turning radium, the vehicles weight, the all-up weight as well as the highest speed and so on, union the choosing engine model we can obtain the important parameters of the max power, the max torque, the displacement and so on. According to the basic parameters of the certain saloon, choose the suitable final drive ratio.
This design is mainly gear's size computation and the examination，the axis size's calcul-ation and the position's determination，the choice design satisfies its bearing capacity the syn- chromesh. Moreover，in view of the gear action's difference, chooses the appropriate bearing on the different axis．Completes the transmission gearbox unit chart，the first axis，the second axis, the intermediate shaft using software Pro/E and CAD, to keep off the gear and the synchromesh design one by one．
 
Key words: transmission; inertial type of synchronizer; gear ratio; countershaft；truck

目  录
 
摘要.................................................................Ⅰ
Abstract..............................................................Ⅱ
第1章 绪论...........................................................1
1.1 概述................................................................ .1
1.2 国内外研究现状............................................... ........1
1.3 研究内容........................................................3
第2章 变速器传动机构布置方案.......................................4
2.1 传动机构布置方案分析....................... ..........................4
2.2 传动装置布置方案分析.................... .............................4
2.3 本章小结................................... ............. ............7
第3章 变速器主要参数的选择.........................................8
3.1 挡数的选择及各挡传动比的确定................ .........................8
3.3.1 确定挡数........................................................8
3.3.2 传动比范围的确定................................................8
3.2 中心距........................ .......................................9
3.3 齿轮参数....................... ......................................9
3.3.1 模数的选取.................. .... ...............................9
3.3.2 压力角..................... ...................................10
3.3.3 螺旋角......................................... ................11
3.4 齿宽计算.............................. ..............................11
3.5 各挡齿轮齿数的分配....................... ...........................11
3.5.1 确定一挡齿轮的齿数.............................................11
3.5.2 对中心距A进行修正................. .............................12
3.5.3 确定齿顶高系数和径向间隙系数......... .... .....................12
3.5.4 计算一挡齿轮参数...............................................12
3.5.5 确定常啮合传动齿轮副的齿数.....................................12
3.5.6 修正螺旋角的值.................................................13
3.5.7 中心距修正.....................................................13
3.5.8 确定常啮合齿轮参数.............................................13
3.5.9 确定其它各挡的齿数.............................................14
3.5.10 确定倒挡的齿数................................................18
3.6 变速器轮齿强度计算..................................................19
3.6.1 齿轮弯曲强度计算...............................................19
3.6.2 齿轮接触应力计算...............................................22
3.6.3 变速器齿轮具体强度校核计算.....................................24
3.7 本章小结.............................................................29
第4章 变速器轴设计计算............................................30
4.1 变速器轴设计................................. .......................30
4.2 初选轴的直径.................................... ....................30
4.3 轴的结构形状..................................... ...................30
4.4 轴的强度和刚度的计算.............................. ..................31
4.4.1 计算各轴上齿轮的圆周力与切向力.................................31
4.4.2 轴的刚度验算.......... ... .....................................33
4.4.3 轴的强度验算...................................................39
4.5 本章小结........................... ... .............................41
第5章 轴承选择与寿命计算............................................42
5.1 使用时间计算.................................... ....................42
5.2 轴承选择与寿命计算............................. .....................42
5.3 本章小结.......................... ..................................43
第6章 变速器的同步器设计及其结构元件..............................42
6.1 同步器设计.................. ........................................44
6.2 同步环主要参数的确定........................ ........................45
6.3 本章小结............................................. ...............47
第7章 应用Pro/E进行变速器的建模与装配... ... ... ... ... ... ....48
7.1 Pro/E软件简介........................ ...............................48
7.2 变速器齿轮集合模型的建立.............. ..............................48
7.2.1 直齿圆柱齿轮几何模型的建立.....................................48
7.2.2 斜齿圆柱齿轮集合模型的建立.....................................51
7.3 变速器轴的几何模型建立............... ...............................55
7.3.1 变速器第一轴的几何模型建立.....................................55
7.3.2 变速器中间轴的几何模型建立.....................................55
7.3.3 变速器第二轴的几何模型建立.....................................56
7.4 轴承的几何模型建立..................... .............................56
7.5 箱体的几何模型建立.................... ..............................57
7.6 变速器零件模型的虚拟装配................ ............................58
7.7 本章小结............................ ................................60
结论.................................................................61
参考文献..............................................................62
致谢.................................................................63
附录.................................................................64