机械5

轿车变速箱设计 摘要 本设计的任务是设计一台用于轿车上的FR式的手动变速器。本设计采用中间轴式变速器，该变速器具有两个突出的优点：一是其直接档的传动效率高，磨损及噪声也最小；二是在齿轮中心距较小的情况下仍然可以获得较大的一档传动比。 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轿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。再结合某些轿车的基本参数，选择适当的主减速比。根据上述参数，再结合汽车设计、汽车理论、机械设计等相关知识，计算出相关的变速器参数并论证设计的合理性。 它功用是：①改变传动比，扩大驱动轮转矩和转速的变化范围，以适应经常变化的行驶条件，如起步、加速、上坡等，同时使发动机在有利的工况下工作；②在发动机旋转方向不变的前提下，使汽车能倒退行驶；③利用空档，中断动力传递，以使发动机能够起动、怠速，并便于发动机换档或进行动力输出。这台变速器具有五个前进档（包括一个超速档五档）和一个倒档，并通过锁环式同步器来实现换档。 关键词：变速器；锁环式同步器；传动比；中间轴；第二轴；齿轮 The desig
n of saloo
n gearbox ABSTRACT The duty of this desig
n is to desig
n a FR type ma
nual tra
nsmissio
n used i
n the saloo
n,It’s the cou
ntershaft-type tra
nsmissio
n gearbox.This tra
nsmissio
n has two promi
ne
nt merits: Firstly,the tra
nsmissio
n efficie
ncy of the direct drive keeps off high, the attritio
n a
nd the
noise are also slightest;Seco
ndly ,it’s allowed to obtai
n i
n the biger gear ratio of the first gear whe
n the ce
nter dista
nce is smaller. Accordi
ng to the co
ntour,track，wheel base，the smallest grou
nd cleara
nce,the smallest tur
ni
ng radium,the vehicles weight, the all-up weight as well as the highest speed a
nd so o
n, u
nio
n the choosi
ng e
ngi
ne model we ca
n obtai
n the importa
nt parameters of the max power,the max torque, the displaceme
nt a
nd so o
n. Accordi
ng to the basic parameters of the certai
n saloo
n,choose the suitable fi
nal drive ratio.Accordi
ng to the above parameters,combi
ni
ng the k
nowledge of automobile desig
n, automobile theory, machi
ne desig
n a
nd so o
n, calculate the correlated parameters of the gearbox a
nd proof the ratio
nality of the desig
n. Its fu
nctio
n is:①Cha
ngi
ng gear ratio,expa
ndi
ng the torque of the drivi
ng wheel a
nd the ra
nge of the rotatio
nal speed,to adapt the travel co
nditio
n which freque
ntly cha
nges, like start, acceleratio
n, climbi
ng a
nd so o
n, simulta
neously causes the e
ngi
ne to work u
nder the adva
ntageous operati
ng mode;②U
nder the premise of the i
nvariable rotatio
n, e
nables the automobile to travel back;③Usi
ng
neutral, severa
nces the power tra
nsmissio
n, to make the e
ngi
ne start, idle, a
nd is adva
ntageous for the e
ngi
ne to shift gears or to carry o
n the dy
namic output. This gearbox has five (i
ncludi
ng over drive—fifth gear) a
nd a reverse gear, a
nd through the i
nertial type of sy
nchro
nizer to realize shift gears. Key wordS：tra
nsmissio
n；i
nertial type of sy
nchro
nizer；gear ratio；cou
ntershaft；seco
nd axis；gear 目录 摘要I ABSTRACT II 符号说明1 前言3 1机械式变速器的概述及其方案的确定7 1.1变速器的功用和要求7 1.2变速器结构方案的确定7 1.2.1变速器传动机构的结构分析与型式选择7 1.2.2倒档传动方案12 1.3变速器主要零件结构的方案分析13 1.3.1齿轮型式13 1.3.2换档结构型式14 2变速器主要参数的选择与主要零件的设计17 2.1变速器主要参数的选择17 2.1.1档数和传动比17 2.1.2中心距18 2.1.3轴向尺寸19 2.1.4齿轮参数19 2.2各档传动比及其齿轮齿数的确定20 2.2.1确定一档齿轮的齿数21 2.2.2确定常啮合齿轮副的齿数21 2.2.3确定其他档位的齿数22 2.2.4确定倒档齿轮的齿数22 2.3齿轮变位系数的选择23 3变速器齿轮的强度计算与材料的选择25 3.1齿轮的损坏原因及形式25 3.2齿轮的强度计算与校核25 3.2.1齿轮弯曲强度计算25 3.2.2齿轮接触应力27 4变速器轴的强度计算与校核29 4.1变速器轴的结构和尺寸29 4.1.1轴的结构29 4.1.2确定轴的尺寸29 4.2轴的校核30 4.2.1第一轴的强度与刚度校核30 4.2.2第二轴的校核计算31 5变速器同步器的设计34 5.1同步器的结构34 5.2同步环主要参数的确定35 6变速器的操纵机构38 7结论39 参考文献40 外文文献41 中文翻译51 致谢58