外文翻译--手动变速器基础

1 附 录 附录 A 英语科技文献 Manual Transmission Basics Its no secret that cars with manual transmissions are usually more fun to drive than their automatic-equipped counterparts. If you have even a passing interest in the act of driving, then chances are you also appreciate a fine-shifting manual gearbox. But how does a manual trans actually work? With our primer on automatics(or slushboxes, as detractors call them) available for your perusal, we thought it would be a good idea to provide a companion overview on manual trannies, too. A brief history lesson shows that manual transmissions preceded automatics by several decades. In fact, up until General Motors offered an automatic in 1938, all cars were of the shift-it-yourself variety. While its logical for many types of todays vehicles to be equipped with an automatic - such as a full-size sedan, SUV or pickup - the fact remains that nothing is more of a thrill to drive than a tautly suspended sport sedan, sport coupe or two-seater equipped with a precise-shifting five- or six-speed gearbox. Its what makes cars such as a Corvette, Mustang, Miata or any BMW sedan or coupe some of the most fun-to-drive cars available today. We know which types of cars have manual trannies. Now lets take a look at how they work. From the most basic four-speed manual in a car from the 60s to the most high-tech six-speed in a car of today, the principles of a manual gearbox are the same. The driver must shift from gear to gear. Normally, a manual transmission bolts to a clutch housing (or bell housing) that, in turn, bolts to the back of the engine. If the vehicle has front-wheel drive, the transmission still attaches to the engine in a similar fashion but is usually referred to as a transaxle. This is because the transmission, differential and drive axles are one complete unit. In a front-wheel-drive car, the transmission also serves as part of the front axle for the front wheels. In the remaining text, a transmission and transaxle will both be referred to using the term transmission. 2 The function of any transmission is transferring engine power to the driveshaft and rear wheels (or axle halfshafts and front wheels in a front-wheel-drive vehicle). Gears inside the transmission change the vehicles drive-wheel speed and torque in relation to engine speed and torque. Lower (numerically higher) gear ratios serve as torque multipliers and help the engine to develop enough power to accelerate from a standstill. Initially, power and torque from the engine comes into the front of the transmission and rotates the main drive gear (or input shaft), which meshes with the cluster or counter shaft gear - a series of gears forged into one piece that resembles a cluster of gears. The cluster-gear assembly rotates any time the clutch is engaged to a running engine, whether or not the transmission is in gear or in neutral. There are two basic types of manual transmissions. The sliding-gear type and the constant-mesh design. With the basic - and now obsolete - sliding-gear type, nothing is turning inside the transmission case except the main drive gear and cluster gear when the trans is in neutral. In order to mesh the gears and apply engine power to move the vehicle, the driver presses the clutch pedal and moves the shifter handle, which in turn moves the shift linkage and forks to slide a gear along the mainshaft, which is mounted directly above the cluster. Once the gears are meshed, the clutch pedal is released and the engines power is sent to the drive wheels. There can be several gears on the mainshaft of different diameters and tooth counts, and the transmission shift linkage is designed so the driver has to unmesh one gear before being able to mesh another. With these older transmissions, gear clash is a problem because the gears are all rotating at different speeds. All modern transmissions are of the constant-mesh type, which still uses a similar gear arrangement as the sliding-gear type. However, all the mainshaft gears are in constant mesh with the cluster gears. This is possible because the gears on the mainshaft are not splined to the shaft, but are free to rotate on it. With a constant-mesh gearbox, the main drive gear, cluster gear and all the mainshaft gears are always turning, even when the transmission is in neutral. Alongside each gear on the mainshaft is a dog clutch, with a hub thats positively splined to the shaft and an outer ring that can slide over against each gear. Both the mainshaft gear and the ring of the dog clutch have a row of teeth. Moving the shift linkage 3 moves the dog clutch against the adjacent mainshaft gear, causing the teeth to interlock and solidly lock the gear to the mainshaft. To prevent gears from grinding or clashing during engagement, a constant-mesh, fully synchronized manual transmission is equipped with synchronizers. A synchronizer typically consists of an inner-splined hub, an outer sleeve, shifter plates, lock rings (or springs) and blocking rings. The hub is splined onto the mainshaft between a pair of main drive gears. Held in place by the lock rings, the shifter plates position the sleeve over the hub while also holding the floating blocking rings in proper alignment. Thats the basics on the inner workings of a manual transmission. As for advances, they have been extensive over the years, mainly in the area of additional gears. Back in the 60s, four-speeds were common in American and European performance cars. Most of these transmissions had 1:1 final-drive ratios with no overdrives. Today, overdriven five-speeds are standard on practically all passenger cars available with a manual gearbox. Overdrive is an arrangement of gearing that provides more revolutions of the driven shaft (the driveshaft going to the wheels) than the driving shaft (crankshaft of the engine). For example, a transmission with a fourth-gear ratio of 1:1 and a fifth-gear ratio of 0.70:1 will reduce engine rpm by 30 percent, while the vehicle maintains the same road speed. Thus, fuel efficiency will improve and engine wear will be notably reduced. Today, six-speed transmissions are becoming more and more common. One of the first cars sold in America with a six-speed was the 89 Corvette. Designed by Chevrolet and Zahnradfabrik Friedrichshafen (ZF) and built by ZF in Germany, this tough-as-nails six-speed was available in the Corvette up to the conclusion of the 96 model year. Today, the Corvette uses a Tremec T56 six-speed mounted at the back of the car. Many cars are available today with six-speeds, including the Mazda Miata, Porsche Boxster S and 911, Dodge Viper, Mercedes-Benz SLK350, Honda S2000, BMW 3-Series and many others. Some of these gearboxes provide radical 50-percent (0.50:1) sixth-gear overdrives such as in the Viper and Corvette, while others provide tightly spaced gear ratios like in the S2000 and Miata for spirited backroad performance driving. While the bigger cars mentioned above such as the Viper and Vette often have two overdrive ratios (fifth and sixth) the smaller cars like the Celica and S2000 usually have one overdriven gear ratio (sixth) and fifth is 1:1. 4 Clearly a slick-shifting manual transmission is one of the main components in a fun-to-drive car, along with a powerful engine, confidence-inspiring suspension and competent brakes. For more information on a manual transmissions primary partner component, check out our basic primer on clutches and clutch operation. 5 附录 B 文献翻译 手动变速器基础 汽车手动变速器相比于自动变速器的驾驶装备来说，在驾驶方面拥有更多的乐趣，这已不再是什么秘密了。如果你有兴趣超速驾驶，那么，你会赞赏对手动变速器汽车的超速进行罚款。但是，手动挡变速器汽车是如何工作的？我们将原始的自动档变速器（或 slushboxex,因为反对者这样称呼他们）提供给您审阅，我们认为将一个概述手册提供给 合作伙伴是一个好主意。 简明的历史教训表明，自从有了手动变速器，几十年间，事实上，直至 1938年通用汽车才开发了自动变速器。所有汽车才有了改变车型的想法。现在多种类型的汽车上配备了自动变速器，虽然这是合乎逻辑的，例如，全尺寸轿车，越野车或皮卡。但事实上，相对于落后的运动轿车，没有比这更刺激的驾驶乐趣了。运动跑车或两个座位的跑车配备了精确地五档或六档变速器，这是为什么使得汽车如克尔维特，野马Miata或任何宝马轿车或跑车强调驾驶乐趣的汽车上市的原因了。 我们知道一些类型的汽车手册，现在让我们看看他们如何工作。 从六十年代最基本的四档手动变速器汽车到今天的高科技六档手动变速器汽车，这些手动档变速器的原理是一样的。驾驶者换挡是从一个齿轮到另一个齿轮，正常情况下，手动变速器螺栓连接离合器壳，而离合器壳的另一面通过螺栓与发动机后部相连。如果车辆是前轮驱动的汽车，变速器仍然以同样的方式连接发动机，通常称之为桥。这是因为变速器，差速器和驱动桥是一个完整的单元。前轮驱动的汽车变速器用于驱动前轴上的前轮。在下面的文章里，变速器和驱动桥都将提到并使用它。 所有变速器的功能都是传递发动机的动力给后驱动轮（或前驱动轮）。变速器内部的齿 轮传动改变车辆的速度和扭矩，它与发动机的转速和扭矩有关。低（数值高）传动比用于多种扭矩，它能够帮助发动机获得足够的动力，用以加速或停车。 起初，功率和扭矩从发动机的前端传递和旋转至主传动齿轮（或输入轴）。其中，啮合的从动齿轮或中间轴齿轮 -一系列齿轮锻造成一个类似于一组齿轮。在任何时候，从动齿轮都处于旋转状态，离合器在一个运行的引擎作用下运行，无论是在齿轮传动或是处于空挡。 有两种基本类型的手动档变速器。滑动齿轮式和常啮合齿轮式。和基本的一样 -6 现在已经过时 -滑动齿轮类型，当档位处于空挡时，没 有什么使传动箱内除了主传动齿轮及齿轮组转动。为了使啮合的齿轮适用于发动机的功率以驱动车辆，驾驶者踩踏离合器踏板和移动变速器操纵杆，这使得换挡拉线和拨叉促使齿轮沿主轴方向滑动，这就是直接换挡。一旦齿轮啮合，离合器踏板释放，发动机功率传递到驱动车轮。可能有几个在不同轴颈上的齿轮和齿，变速器的换挡杠杆机构是被设计用来方便驾驶员换挡的机构。这些过时的变速器，齿轮的碰撞是一个问题，因为齿轮都以不同的速度旋转。 所有的现代变速器都是常啮合齿轮式，它仍然使用了类似的布置，齿轮滑动齿轮类型。然而，所有的主动齿轮与从动齿轮啮 合，这是因为齿轮的主轴不以花键轴的形