汽车驱动桥课程毕业设计外文文献翻译、中英文翻译、外文翻译

附 录 A 一、英文原材料 Drive Axle All vehicles have some type of drive axle/differential assembly incorporated into the driveline. Whether it is front, rear or four wheel drive, differentials are necessary for the smooth application of engine power to the road. The drive axle must transmit power through a 90 angle. The flow of power in conventional front engine/rear wheel drive vehicles moves from the engine to the drive axle in approximately a straight line. However, at the drive axle, the power must be turned at right angles (from the line of the driveshaft) and directed to the drive wheels. This is accomplished by a pinion drive gear, which turns a circular ring gear. The ring gear is attached to a differential housing, containing a set of smaller gears that are splined to the inner end of each axle shaft. As the housing is rotated, the internal differential gears turn the axle shafts, which are also attached to the drive wheels. The differential is an arrangement of gears with two functions: to permit the rear wheels to turn at different speeds when cornering and to divide the power flow between both rear wheels. (1)The accompanying illustration has been provided to help understand how this occurs. The drive pinion, which is turned by the driveshaft, turns the ring gear. (2)The ring gear, which is attached to the differential case, turns the case. (3)The pinion shaft, located in a bore in the differential case, is at right angles to the axle shafts and turns with the case. (4)The differential pinion (drive) gears are mounted on the pinion shaft and rotate with the shaft. (5)Differential side gears (driven gears) are meshed with the pinion gears and turn with the differential housing and ring gear as a unit. (6)The side gears are splined to the inner ends of the axle shafts and rotate the shafts as the housing turns. (7)When both wheels have equal traction, the pinion gears do not rotate on the pinion shaft, since the input force of the pinion gears is divided equally between the two side gears. (8)When it is necessary to turn a corner, the differential gearing becomes effective and allows the axle shafts to rotate at different speeds. As the inner wheel slows down, the side gear splined to the inner wheel axle shaft also slows. The pinion gears act as balancing levers by maintaining equal tooth loads to both gears, while allowing unequal speeds of rotation at the axle shafts. If the vehicle speed remains constant, and the inner wheel slows down to 90 percent of vehicle speed, the outer wheel will speed up to 110 percent. However, because this system is known as an open differential, if one wheel should become stuck (as in mud or snow), all of the engine power can be transferred to only one wheel. Engineers searched diligently for ways to allow each driving wheel to operate at its own speed. Many ideas were tried with mixed results before the basic design for the present-day, standard differential was finally developed. The successful idea that is still used in principle today was to divide the engine power by dividing the axle in two-attaching each driving wheel separately to its own half-axle and placing in between, an ingenious, free-rotating pinion and gear arrangement. The arrangement was called the differential because it differentiates between the actual speed needs of each wheel and splits the power from the engine into equal driving force to each wheel. On/off road vehicles and other trucks required to haul heavy loads are sometimes equipped with double reduction axles. A double reduction axle uses two gear sets for greater overall gear reduction and peak torque development. This design is favored for severe-ser-vice applications, such as dump trucks, cement mixers, and other heavy haulers. The double reduction axle uses a heavy-duty spiral bevel or hypoid pinion and ring gear combination for the first reduction. The second reduction is accomplished with a wide-faced helical spur pin-ion and gear set. The drive pinion and ring gear function just as in a single reduction axle. However, the differential case is not bolted to the ring gear. Instead, the spur pinion is keyed to and driven by the ring gear. The spur pinion is in turn constantly meshed with the helical spur gear to which the differential case is bolted. Many heavy duty trucks are equipped with two rear drive axles. These tandem axle trucks require a special gear arrangement to deliver power to both the forward and rearward rear driving axles. This gearing must also be capable of allowing for speed differences between the axles. Two axle hub arrangements are available to provide support between the axle hub and the trucks wheels: the semi-floating type axle and the fully floating type axle. Of the two ,the semi-floating is the simplest, cheapest design to incorporate ,but the fully floating axle is more popular in heavy-duty trucks. In the semi-floating type axle, drive power from the differential is taken by each axle half-shaft and transferred directly to the wheels. A single bearing assembly, located at the outer end of the axle, is used to support the axle half-shaft. The part of the axle ex-tending beyond the bearing assembly is either splined or tapered to a wheel hub and brake drum assembly. The main disadvantage of this type of axle is that the outer end of each axle shaft must carry and support the weight of the truck that is placed on the wheels. If an axle half-shaft should break ,the trucks wheel will fall off. Drive axle operation is controlled by the differential carrier assembly. A differential carrier assembly consists of a number of major components. These include: 1. Input shaft and pinion gear 2. Ring gear 3. Differential with two differential case halves, a differential spider ,four pinion gears ,and two side gears with washers. This differential assembly fits between the axle shafts, with the shafts being splined to the differential side gears. The parts of the differential carrier are held in position by a number of bearings and thrust washers. The leading end of the input shaft is connected to the drive shaft by a yoke and universal joint. The pinion gear on the other end of the input shaft is in constant mesh with the ring gear. The ring gear is bolted to a flange on the differential case. Insied the case, the legs of the spider are held in matching grooves in the case halves. The legs of the spider also support the four pinion gears. In addition ,the case houses the side gears ,which are in mesh with the pinions and are splined to the axle shafts. When the drive shaft torque is applied to the input shaft and drive pinion, the input shaft and pinion rotate in a direction that is perpendicular to the trucks drive axles. The drive pinion is beveled at 45 degrees and engages the ring gear, which is also beveled at 45 degrees, causing the ring gear to revolve at 90 degrees to the drive shaft. This means the torque flow changes direction and becomes parallel to the axles and wheels. The drive shaft must also be able to change in length while transmitting torque. As the rear axle reacts to road surface changes, torque reactions and braking forces, it tends to rotate for-ward or backward, requiring a corresponding change in the length of the drive shaft. In order to transmit engine torque to the rear axles, the drive shaft must be durable and strong. An engine producing 1 000 pound-feet of torque, when multiplied by a 12 to t gear ration in the transmission, will deliver 12 000 pound-feet breakaway torque to the drive shaft. The shaft must be strong enough to deliver this twisting force to a loaded axle without deforming or cracking under the strain. Drive shafts are constructed of high-strength steel tubing to provide maximum strength with minimum weight. The diameter of the shaft and wall thickness of the tubing is determined by several factors maximum torque and vehicle payload, type of operation, road conditions, and the brake torque that might be encountered. One-piece ,two-piece ,and three-piece drive shafts are used, depending on the length of the drive line. Each end of the drive shaft has a yoke used to connect the shaft to other drive line components. The yoke might be rigidly welded to the shaft tube or it might be a spline, or slip yoke. The tube yokes are connected through universal joints to end yokes on the output and input shafts of the transmission and axle. A typical slip joint consists of a hardened, ground splined shaft welded to the drive shaft tube that is inserted into a slip yoke that has matching internal splines. The sliding splines between a slib joint and a permanent joint must support the drive shaft and be capable of sliding under full torque loads. The propeller shaft is generally hollow to promote light weight and of a diameter sufficient to impart great strength. Quality steel, aluminum, and graphite are used in its construction. Some have a rubber mounted torsional damper. The universal yoke and splined stub (where used) are welded to the ends of a hollow shaft. The shaft must run true, and it must be carefully balanced to avoid vibrations. The propeller shaft is often turning at engine speeds. It can cause great damage if bent, unbalanced or if there is wear in the universal joints. As the rear axle moves up and down, it swings on an arc that is different from that of the drive line. As a result, the distance between transmission and rear axle will change to some extent. When the propeller shaft turns the differential, the axles and wheels are driven forward. The driving force developed between the tires and the road is first transferred to the rear axle housing. From the axle housing, it is transmitted to the frame or body in one of three ways: 1. Through leaf springs that are bolted to the housing and shackled to the frame. 2. Through control or torque arms shackled to both frame and axle housing. 3. Through a torque tube that surrounds the propeller shaft which is bolted to the axle housing and pivoted to the transmission, by means of a large ball socket. 二、中文翻译 驱动桥 汽车传动系统中驱动桥和差速器有许多形式。无论是前轮、后轮还是四轮驱动，差速器都是必要的，以便使发动机的功率充分的发挥到路面上。 驱动桥必须通过一个 90角传递动力。以传统的后轮驱动汽车为例， 动力由前置引擎传到大致在一条直线上的驱动桥，然后动力必须经过一个直角传递给驱动车轮。 这一过程是通过一个小齿轮传递到一个齿圈上而完成的。该齿圈连接到差速器壳，壳里面装有一组小齿轮，小齿轮与带有花键的每个轴的轴端相联接，由桥壳的旋转，从而差速齿轮带动轴转动，这个轴同时连接的就是驱动车轮。 图示为一个典型驱动桥的组成 差速器齿轮具有两个基本的功能：在转弯时允许后轮以不同的速度转动并将动力分配到两后轮。 （ 1）提供的说明是为了帮助理解这一过程是如何实现的。轴带动小驱动齿轮在齿圈上旋转。 （ 2）该齿圈与差速器壳相连 ，并带动壳旋转。 （ 3）差速器壳内设有一小孔，放置一个小齿轮轴，该小轴与差速器成直角，并随壳体转动。 （ 4）差速行星齿轮驱动装在小轴上的齿轮，使轴转动。 （ 5）差速器边上的齿轮（驱动齿轮）与小齿轮啮合，并与做在一体的差速器壳和齿圈一起转动。 （ 6）一侧带花键的齿轮与两轴端配合，随桥壳旋转。 （ 7）当两车轮具有相同的驱动力的时候，小齿轮（行星齿轮）在其轴架（行星架）上不旋转，输入到小齿轮上的力平均分配给两端的齿轮。 （ 8）当需要转弯时，差动齿轮开始起作用，能够实现两端的半轴以不同的速度旋转。 由于内侧车轮速度 减慢，同侧的花键轴齿轮也变慢，行星齿轮作为平衡杠杆，保持两边的轮齿负荷相等，同时允许两边的半轴以不同的的速度旋转。如果汽车的行进速度保持不变，内侧车轮的速度将减低 90%。外侧车轮的速度将增加到 110%。但是，因为系统有差速器，所以一旦有一个车轮转速保持不变（如在泥或雪地），那么 所有的发动机功率 将全部 转移到 另外的 一个车轮。 工程师们努力地寻找方法使每个驱动轮都按照自己的速度运行。在如今标准的差速器被最终发明出来之前，许多想法被交叉尝试。目前在理论上非常成功的、一直沿用到今天的想法是通过把车轴分离成对称的两部分 。每一个半轴都连接到分离的驱动轮上，然后中间安放一个独立的自由旋转的小齿轮和其它两个齿轮来分离来自发动机的动力。这个结构被称为差速装置。因为这种装置能提供给每个车轮实际所需要的速度并且把来自发动机的动力分成相同的驱动力作用给每个车轮。许多卡车有时需要装备双级减速驱动桥来拖拽重物。双级减速驱动桥使用两套减速齿轮来降低速度使转矩达到峰值。这种设计是非常受优待的例如自卸式卡车、混凝土搅拌车和其它重型货车。 双减速车桥采用了重型的螺旋锥齿轮或准双曲面齿轮和环行齿轮配合从而进行第一级减速。第二级减速是通过宽面的螺旋柱 形直齿轮及其它齿轮组的配合完成的。主动小齿轮和环行齿轮在 单级减速桥 上运行，而差速器箱没有被环形齿轮锁死，相反，环形齿轮能将柱形直齿轮键入并驱动，柱形直齿轮就可以依次不断地与差速器箱中的螺旋正齿轮相啮合。 许多重型载货汽车都配备了两个后驱动桥，这种平衡悬架轴的卡车需要一种特殊的齿轮配置方法来解决后驱动桥上的向前与向后的传动。这些齿轮必须要考虑到车轴间的转速差。两个车轴轴毂的排列为轴毂和车轮间提供了有力的支持。在 半浮动式轴 与 全 浮动式轴 中， 半浮动式轴 的设计较简单、价格便宜的，而全 浮动式轴 多受欢迎于重型卡车中。 对 于半浮动式轴，来自差速器的动力施加与两个半轴，并直接传递到轮子上。一个单轴承组（位于轴承外端）被用于支撑半轴。轴端外延到轴承组上