（毕业设计 页数：33 字数：16874）载重汽车后桥设计

摘要：载重汽车后桥（驱动桥）作为汽车四大总成之一，它承载着载重汽车的满载荷负重及地面经车轮、车架及承载式车身经悬架给予的铅垂力、纵向力、横向力及其力矩，以及冲击载荷；后桥（驱动桥）还传递着传动系中的最大转矩，桥壳还承受着反作用力矩。汽车驱动桥结构型式和设计参数除对汽车的可靠性与耐久性有重要影响外，也对汽车的行驶性能如动力性、经济性、平顺性、通过性、机动性和操动稳定性等有直接影响。另外，载重汽车驱动桥在汽车的各种总成中也是涵盖机械零件、部件、分总成等的品种最多的大总成。例如，驱动桥包含主减速器、差速器、驱动车轮的传动装置（半轴及轮边减速器）、桥壳和各种齿轮。由上述可见，汽车驱动桥设计涉及的机械零部件及元件的品种极为广泛，对这些零部件、元件及总成的制造也几乎要涉及到所有的现代机械制造工艺。当采用大功率发动机输出大的转矩以满足目前载重汽车的快速、重载的高效率、高效益的需要时，必须要搭配一个高效、可靠的后桥。所以采用传动效率高的单级减速驱动桥已成为未来重载汽车的发展方向。本文参照传统驱动桥的设计方法进行了载重汽车驱动桥的设计。本文首先确定主要部件的结构型式和主要设计参数；然后参考类似驱动桥的结构，确定出总体设计方案；最后对主，从动锥齿轮，半轴齿轮和全浮式半轴强度进行校核以及对支承轴承进行了寿命校核。
本设计有以下两大难题，一是将发动机输出扭矩通过万向传动轴将动力传递到后轮子上，达到更好的车轮牵引力与转向力的有效发挥，从而提高载重汽车的行驶能力。二是差速器向两边半轴传递动力的同时，允许两边半轴以不同的转速旋转，满足两边车轮尽可能以纯滚动的形式作不等距行驶，减少轮胎与地面的摩擦。
本设计具有以下的优点：由于的是采用中央单级减速驱动桥，使得整个后桥 的结构简单，制造工艺简单，从而大大的降低了制造成本。并且，弧齿锥齿轮的单级主减速器提高了后桥的传动效率，提高了传动的可靠性。
本设计的最大特点是：主减速器不是采用传统的双曲面锥齿轮，而是采用弧齿锥齿轮。弧齿锥齿轮与其他的齿轮相比，具有工作平稳，噪音和振动小的优点，并且它的传动效率可高达99%。

关键字：载重汽车;后桥;单级减速桥;弧齿锥齿轮

After the truck bridge design

Abstract ：Truck after the bridge (driven Bridge) as a vehicle one of the four trains, carrying a full load of the truck load and ground by the wheels, chassis and body-bearer for the suspension of the vertical, vertical edge , The horizontal force and torque, and the impact load; after the bridge (Drive Bridge) also convey transmission of the biggest torque, the bridge also bear a shell counterproductive torque.Car driver and the structure of the bridge design parameters in addition to the reliability and durability of the car with important influence, but also on the performance of motor vehicles such as the driving force of economy, ride through, maneuverability and stability actuator Has a direct impact. In addition, the truck driver bridge in the assembly of motor vehicles is also covered various mechanical parts, components, sub-assembly, and other species up to the great assembly. For example, the drive includes the main bridge reducer, differential, the gear wheel drive (axle and wheel-reducer), shell and all kinds of gear Bridge.Visible from above, the car driver involved in bridge design mechanical parts and components of the very wide variety of these parts, components and assembly manufacturing to design to almost all the modern machinery manufacturingprocess.
When a large high-power engine torque output to meet the current truck fast, dependable high-efficiency, cost-effective when necessary, must be with an efficient and reliable rear axle. Therefore, the efficient use of transmission slowdown in single-stage driver bridge has become a heavy vehicle of the future development direction. Reference to the traditional paper-driven approach to the design of the bridge the truck driver bridge design. This article first to identify the main components of the structure of the main design parameters and then refer to a similar drive the bridge structure, identified design programmes; Finally, the owners, driven bevel gear, Cone planetary gear differential, axle gear, the whole floating - Axle and the overall strength of the shell-bridge to check bearing
s and bearing the school life.
This design has the following two problems, First will be the engine torqueoutput to force through universal drive shaft after the transfer to the wheels, toachieve better traction and steering wheel of the effective play, thereby enhancing the truck traffic capacity. The second is the differential to transfer power on both sides of the axle at the same time, allowing both sides axle with a different rotation speed, the wheel as much as possible to satisfy both sides in the form of pure rolling for not moving equidistant to reduce the tyre friction with the ground.
This design has the following advantages: Because the central slowdown insingle-stage driver Bridge, the bridge after making the whole structure is simple,simple manufacturing process, thus greatly reducing manufacturing costs. In addition, the spiral bevel gear reducer single-stage main bridge increased after the transmission efficiency, improved transmission reliability.
The most important feature of this design is: Lord reducer is not a conventional double-bevel gear surface, but a spiral bevel gear. Spiral bevel gear and other gear compared with the smooth work, noise and vibration on the merits, and its transmission efficiency can be as high as 99%.

Keyword: truck; After the bridge ; Single-stage slowdown Bridge; Spiral bevel gear


目录
前言 2
1 后桥结构方案分析 3
2 主减速器设计 5
2.1 主减速器的结构形式 5
2.1.1 主减速器的齿轮类型 5
2.1.2 主减速器的减速形式 5
2.1.3 主减速器主，从动锥齿轮的支承形式 5
2.2 主减速器的基本参数选择与设计计算 5
2.2.1 主减速器计算载荷的确定 5
2.2.2 主减速器基本参数的选择 7
2.2.3 主减速器圆弧锥齿轮的几何尺寸计算 9
2.2.4 主减速器圆弧锥齿轮的强度计算 10
2.2.5 主减速器齿轮的材料及热处理 15
2.2.6 主减速器轴承的计算 15
3 驱动半轴的设计 21
3.1 全浮式半轴计算载荷的确定 21
3.2 全浮式半轴的杆部直径的初选 22
3.3 全浮式半轴的强度计算 22
3.4 半轴花键的强度计算 22
3.5 半轴的结构设计及材料的热处理 23
结论 25
参考文献 26
附件清单 28
致谢 29

前言
汽车后桥（驱动桥）位于传动系的末端。其基本功用首先是增扭，降速，改变转矩的传递方向，即增大由传动轴或直接从变速器传来的转矩，并将转矩合理的分配给左右驱动车轮；其次，驱动桥还要承受作用于路面或车身之间的垂直力，纵向力和横向力，以及制动力矩和反作用力矩等。驱动桥一般由主减速器，差速器，车轮传动装置和桥壳组成。
对于重型载货汽车来说，要传递的转矩较乘用车和客车，以及轻型商用车都要大得多，以便能够以较低的成本运输较多的货物，所以选择功率较大的发动机，这就对传动系统有较高的要求，而驱动桥在传动系统中起着举足轻重的作用。随着目前国际上石油价格的上涨，汽车的经济性日益成为人们关心的话题，这不仅仅只对乘用车，对于载货汽车，提高其燃油经济性也是各商用车生产商来提高其产品市场竞争力的一个法宝，因为重型载货汽车所采用的发动机都是大功率，大转矩的，装载质量在十吨以上的载货汽车的发动机，最大功率在140KW以上，最大转矩也在700N•m以上，百公里油耗是一般都在34升左右。为了降低油耗，不仅要在发动机的环节上节油，而且也需要从传动系中减少能量的损失。这就必须在发动机的动力输出之后，在从发动机—传动轴—驱动桥这一动力输送环节中寻找减少能量在传递的过程中的损失。在这一环节中，发动机是动力的输出者，也是整个系统的心脏，而驱动桥则是将动力转化为能量的最终执行者。因此，在发动机相同的情况下，采用性能优良且与发动机匹配性比较高的驱动桥便成了有效节油的措施之一。所以设计新型的驱动桥成为新的课题。
目前国内重型车桥生产企业也主要集中在中信车桥厂、东风襄樊车桥公司、济南桥箱厂、汉德车桥公司、重庆红岩桥厂和安凯车桥厂几家企业。这些企业几乎占到国内重卡车桥90%以上的市场。