驱动桥 毕业论文外文翻译.doc

附 录b一、英文原材料 drive axleall-terrain vehicle needs frequently goes in bad road and in the roadless situation, particularly the military automobiles travel condition is worse, this requests to increase the automobile driving gears number, therefore, all-terrain vehicle uses the multiple spindle actuation. for example, if front-wheel drives automobile two front wheels will both fall into the ditch (this kind of situation to meet frequently on bad road), that automobile will be unable engines power produces through the wheel and the ground friction the driving influence to continue to go forward. but if the this vehicles four wheels can have driving influence, that but also two have not fallen into the ditch the wheel to be able the normal work, causes the automobile to continue to go. function, on multiple spindle actuation automobile, to output the power distribution is equipped with the transfer case for various driving axles. the transfer case is equipped with the high low gear generally, by further expands when the difficult area goes the transmission when gear number. the transfer cases function is the power distribution which outputs the transmission gearbox to various driving axles, and further increases the torque. the transfer case is also a gear drive system, it fixes alone on the frame, its input axis and transmission gearboxs output shaft with the rotary transmission device connection, transfer cases output shaft has certain, passes through the rotary transmission device and various driving axles separately is connected. majority transfer cases, because must play the reduction of speed to increase the moment the role, but is bigger than gear boxs load, therefore in transfer cases chang nie the gear is a helical gear, the bearing also uses the circular cone roller bearings supporting. drive shafts- or propeller shafts, as they are sometimes called-have one basic function. transferring power or torque from one drive line component to another in a smooth, continuous fashion. in a heavy-duty truck, that means transmitting engine torque from the output shaft of the transmission to a rear axle or to an auxiliary transmission. drive shafts are also used to connect forward and rear axles on 4 x 6 tractors. in most cases, a drive shaft must transfer torque at an angle to the centerlines of the drive line components it is fastened to. be- cause the rear axle is not connected to the rigid rails of the truck frame but is mounted to the rear suspension system, the drive shaft must also be able to change angles as the rear suspension jounces and rebounds.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.when the car rounds a curve, the outer wheel must turn faster than the inner wheel. to permit this, the two pinion gears rotate on their pinion shaft, transmitting more turning movement to the outer side gear than to the inner side gear. thus, the side gear on the outer-wheel axle turns more rapidly than the side gear on the inner-wheel axle. this permits the outer wheel to turn more rapidly while the car is rounding the curve，so that the side gears turn at the same speed as the ring gear, causing both rear wheels to turn at the same speed, also。during one revolution of the ring gear, one gear makes two revolutions, one with the ring gear and another as the pinions walk around the other gear. as a result, when the drive wheels have unequal resistance applied to them, the wheel with the least resistance turns more revolutions. as one wheel turns faster, the other turns proportionally slower.the differential case is supported in the carrier by two tapered-roller side bearings. this assembly can be adjusted from side to side to provide the proper backlash between the ring gear and pinion and the required side bearing preload. this adjustment is achieved by threaded bearing adjusters on some units and the placement of selective shims and spacers on others. it is to be noted that simple universal joint does not transmit the motion uniformly when the shafts are operating at an angle, except in constant velocity type universal joint. because the pivot pins do not revolve in the same plane, the driven shaft will increase to a maximum and decrease to a minimum twice in each revolution. although the degree of variation is small, however, it may be minimized by the use of two universal joints. the two joints are arranged so that the non-uniform rotation of each joint tends to neutralize that of the other.the propeller shaft is a driving shaft that connects the transmission to the differential. the output shaft or main shaft from the transmission and pinion shaft extending from the differential unit are connected to the propeller shaft and the universal joints. a sliding joint is also used between the propeller shaft and the universal joint near the gear box. the rotary motion of the transmission main shaft is carried out through the propeller shaft to the differential, causing, the rear wheels to rotate. the propeller shaft has to withstand the torsional stresses of the transmitting torque, and yet it must be light and well balanced so that vibrations and whip will not occur at high speeds. for these reasons, it is made of a strong steel tube. solid propeller shafts are also used. the propeller shaft may be exposed to the atmosphere or protected by an outer tube. some applications include bearings at or near the propeller shaft centre to support the shaft. on some applications, the propeller shaft is in two sections, supported by a centre bearing and coupled together by universal joints.it is to be noted that the transmission main shaft and the differential pinion shaft are not in one horizontal level. the rear axle housing with differential is attached to the frame by springs, therefore the distance between the gear box and the differential changes due to road irregularities. this also changes the angle of drive. in order that the propeller shaft must take curve of these two changes it is provided with one or more universal joints to permit variations in the angle of drive. also, it must be provided with a sliding joint that permits the effective length of the propeller shaft to change.a universal joint is used where two shafts are connected at an angle to transmit torque. in the transmission system of a motor vehicle, the transmission main shaft, propeller shaft and the differential pinion shaft are not in one line, and hence the connection between them are made by universal joint. one universal joint is used to connect the transmission main shaft and the propeller shaft, other universal joint is used to connect the other end of the propeller shaft and the differential pinion shaft. thus, the connections between the three shafts are flexible and at an angle with each other. the universal joint permits the torque transmission not only at angle, but also while this angle is changing constantly.a simple universal joint consists of two y shaped yokes, one on the driving shaft and the other on the driven shaft, and a cross-piece called the spider. the four arms of spider, known as trunnions, are assembled into bearing in the end of the two shaft angle to each other, the bearings in the yokes permits the yokes to swing around on the trunnions with each revolution.next to the gear box in the transmission system is the propeller shaft. it is connected between the gear box and the differential with universal joint at each end. the torque is transmitted from the gear box to the differential through the propeller shaft and universal joints. the differential then transmits the torque to the rear axial to which the rear wheels are connected.principle, transfer case various axes use two circular cone roller bearings supporting, its bearing loose allowance uses the corresponding adjustment pad adjustment. cross-country vehicle when the good path goes, is the throttle closure consumption and the power transmission part and the tyre wear, as soon as moves must shut off passes the front axle power. when cross-country running, if needs the low speed files power, to prevent the rear axle of car and the intermediate axle overload, should cause the low speed files power to share by all driving axles. therefore, the half motion control mechanism has the following request: must first joins the front axle not to hang up arrives at the fast files, must first withdraws from the low speed files, do not take off the front axle.二、中文翻译驱动桥越野车需要经常在坏路和无路情况下行驶，尤其是军用汽车的行驶条件更为恶劣，这就要求增加汽车驱动轮的数目，因此，越野车都采用多轴驱动。例如，如果一辆前轮驱动的汽车两前轮都陷入沟中(这种情况在坏路上经常会遇到)，那汽车就无法将发动机的动力通过车轮与地面的磨擦产生驱动力而继续前进。而假如这辆车的四个轮子都能产生驱动力的话，那么，还有两个没陷入沟中的车轮能正常工作，使汽车继续行驶。 功用，在多轴驱动的汽车上，为了将输出的动力分配给各驱动桥设有分动器。分动器一般都设有高低档，以进一步扩大在困难地区行驶时的传动比及排挡数目。分动器的功用就是将变速器输出的动力分配到各驱动桥，并且进一步增大扭矩。分动器也是一个齿轮传动系统，它单独固定在车架上，其输入轴与变速器的输出轴用万向传动装置连接，分动器的输出轴有若干根，分别经万向传动装置与各驱动桥相连。大多数分动器由于要起到降速增矩的作用而比变速箱的负荷大，所以分动器中的常啮齿轮均为斜齿轮，轴承也采用圆锥滚子轴承支承。 驱动轴或传动轴，有一个基本功用：将功率或扭矩由传动线上的一个零件传动另一个零件，既平顺又连续。重型货车发动的扭矩从边速器的从动轴传到后桥或一个副变速箱。大多数情况下驱动轴必须把来自于发动机的高速旋转扭矩转换成为驱动组件的直线运动。由于后轴不是直接连接在车架上的而是通过后悬架连接的，同时驱动桥必须能够变换角度来适应后悬架的弹性跳动。驱动桥在传递转矩的同时还能改变长度。因为后轴反映路面的变化，转矩的反映和制动力的变化，适应向前或者向后的旋转。同时还要适应驱动桥的长度变化。为了把发动机的转矩传递到后轴，驱动桥必须耐用而且结实。发动机产生1000镑尺的转矩时乘以一个齿轮12个齿在驱动桥上就产生了12000镑尺的转矩。后轴必须足够结实来传递扭转力矩给承载轴上不能产生变形和段裂。驱动桥是由高强度的空心钢管制成的以最小的重量来提供最大的动力轴的直径和轴壁的薄厚是由扭矩的峰值、车辆的额定载重、运行的方式、路面状况和制动力矩共同决定的。每一个驱动桥的末端都有十字轴用来连接轴和其它的纵向驱动组件的。这个十字轴被刚性的焊接在半轴的软管上或者是滑动叉上。这个支撑管一头连接着万向节，另一头接在支配管上用来输入和输出变速器和轴的动力。 当汽车转弯时，外侧车轮就必须比内侧车轮转的更快。为了达到这一目的，两个行星齿轮在齿轮轴上转动，给外侧的车论提供比内侧的车轮更多的运动，这样外侧车轮轴上的半轴齿轮比内侧车轮轴上的的半轴齿轮转动更快。这样半轴齿轮与冠状齿轮的转速相等，从而使两个后轮也以相同的速度转动。差速器壳由两个圆锥滚子轴承支撑着，在这个机构中可以调整两个轴承间的间隙来满足冠状齿轮与驱动齿轮间所必需的轴承预紧度。这种调整是依靠调整轴承一些部件的螺栓或者调整轴承的调整垫片或衬垫来实现的。在传动系统里的变速箱旁边是传动轴。 它