汽 车 设 计 课程设计说明书 课题：乘用车主减速器设计
姓 名： 学 号： 专 业：车辆工程 班 级：
指导教师：
二 〇 一 二 年 七 月
摘 要
汽车正常行驶时，发动机的转速通常在2000至3000r/min左右，如果将这么高的转速只靠变速箱来降低下来，那么变速箱内齿轮副的传动比则需很大，而齿轮副的传动比越大，两齿轮的半径比也越大，换句话说，也就是变速箱的尺寸会越大。另外，转速下降，而扭矩必然增加，也就加大了变速箱与变速箱后一级传动机构的传动负荷。所以，在动力向左右驱动轮分流的差速器之前设置一个主减速器。
主减速器的存在有两个作用，第一是改变动力传输的方向，第二是作为变速器的延伸为各个档位提供一个共同的传动比。 变速器的输出是一个绕纵轴转动的力矩，而车轮必须绕车辆的横轴转动，这就需要有一个装置来改变动力的传输方向。之所以叫主减速器，就是因为不管变速器在什么档位上，这个装置的传动比都是总传动比的一个因子。有了这个传动比，可以有效的降低对变速器的减速能力的要求，这样设计的好处是可以有效减小变速器的尺寸，使车辆的总布置更加合理
汽车主减速器最主要的作用，就是减速增扭。我们知道发动机的输出功率是一定的，根据功率的计算公式W=M*v（功率=扭矩*速度），当通过主减速器将传动速度降下来以后，能获得比较高的输出扭矩，从而得到较大的驱动力。此外，汽车主减速器还有改变动力输出方向、实现左右车轮差速或中后桥的差速功能。
关键字：传动系；驱动轴；主减速器
Abstract
Normal driving of the car, the engine speed is usually around 2000 to 3000r/min, if such a high speed alone gearbox to reduce down, then the gearbox Gears gear than you need, and the drive gear pairratio increases, the radius of the two gears is greater, in other words, is the gearbox size larger. In addition, the speed decreases, torque bound to increase, will increase the transmission load of a gearbox and gearbox transmission. Therefore, prior to the diversion of power to the left and right driving wheel differential to set up a main gear box.
The existence of the main gear box has two roles, the first is to change the direction of power transmission, and the second is as an extension of the transmission to provide a common transmission ratio for each gear. A transmission output is around the longitudinal axis of rotation of the torque, the wheels have to go around the horizontal axis rotation of the vehicle, which requires a device to change the direction of the transmission of power. Is called a main gear box, because regardless of transmission, the gear transmission ratio of this device are the total transmission ratio of a factor. With this transmission ratio, can effectively reduce the ability to slow down transmission, the benefits of this design can effectively reduce the size of the transmission, so that the general arrangement of the vehicle a more reasonable
Auto main gear box of the most important role is to slow the increase in twist. We know that the engine output power is certain, to get a relatively high output torque, larger driving force. In addition, the automotive main gear box to change the direction of power output, left and right wheel differential or rear axle differential features.
Keywords: transmission system; drive shaft; main reducer
目录
1课程设计目的 ..................................................... 1
2单级主减速器结构方案分析 ................................................................................... 2 2.1主减速器的的结构形式 .................................................................................... 2 2.1.1主减速器齿轮的类型 ................................................................................. 2 2.1.2主减速器主动锥齿轮的支承型式及安置方法 ......................................... 3 2.1.3主减速器从动锥齿轮的支承型式及安置方法 ......................................... 4 2.1.4主减速器的轴承预紧及齿轮啮合调整 ..................................................... 4 2.1.5主减速器的减速型式 ................................................................................. 5 2.2主减速器的基本参数选择与设计计算 ............................................................ 7 2.2.1主减速比i0的确定 .................................................................................... 7 2.2.2主减速齿轮计算载荷的确定 ..................................................................... 8 2.3主减速器齿轮基本参数的选择 ...................................................................... 10 2.3.1齿数的选择 ............................................................................................... 10 2.3.2节圆直径的选择 ....................................................................................... 11 2.3.3齿轮端面模数的选择 ............................................................................... 11 2.3.4齿面宽的选择 ........................................................................................... 12 2.3.5双曲面齿轮的偏移距E ........................................................................... 12 2.3.6螺旋锥齿轮螺旋方向 ............................................................................... 13 2.3.7螺旋角的选择 ........................................................................................... 13 2.3.8齿轮法向压力角的选择 ........................................................................... 16 2. 4螺旋锥齿轮几何尺寸计算 ............................................................................. 17 2.5主减速器螺旋锥齿轮强度计算 ...................................................................... 20 2.5.1计算圆周力 ................................................................................................. 20 2.5.2轮齿弯曲强度： ......................................................................................... 21 2.5.3轮齿接触强度： ......................................................................................... 24 2.6锥齿轮的材料及热处理： ................................................................................ 26 3主减速器轴承的计算 ............................................................................................... 28 3.1作用在主减速器主动齿轮上的力 .................................................................... 28