外文翻译--手动变速器如何工作

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1、 1 附 录 How Manual Transmissions Work If you drive a stick-shift car, then you may have several questions floating in your head. How does the funny H pattern that I am moving this shift knob through have any relation to the gears inside the transmission? What is moving inside the transmission when I

2、move the shifter? When I mess up and hear that horrible grinding sound, what is actually grinding? What would happen if I were to accidentally shift into reverse while I am speeding down the freeway? Would the entire transmission explode? In this article, well answer all of these questions and more

3、as we explore the interior of a manual transmission. Cars need transmissions because of the physics of the gasoline engine. First, any engine has a redline - a maximum rpm value above which the engine cannot go without exploding. Second, if you have read How Horsepower Works, then you know that engi

4、nes have narrow rpm ranges where horsepower and torque are at their maximum. For example, an engine might produce its maximum horsepower at 5,500 rpm. The transmission allows the gear ratio between the engine and the drive wheels to change as the car speeds up and slows down. You shift gears so the

5、engine can stay below the redline and near the rpm band of its best performance. Ideally, the transmission would be so flexible in its ratios that the engine could always run at its single, best-performance rpm value. That is the idea behind the continuously variable transmission (CVT). A CVT has a

6、nearly infinite range of gear ratios. In the past, CVTs could not compete with four-speed and five-speed transmissions in terms of cost, size and reliability, so you didnt see them in production automobiles. These days, improvements in design have made CVTs more common. The Toyota Prius is a hybrid

7、car that uses a CVT. The transmission is connected to the engine through the clutch. The input shaft of the transmission therefore turns at the same rpm as the engine. A five-speed transmission applies one of five different gear ratios to the input shaft to 2 produce a different rpm value at the out

8、put shaft. A Very Simple Transmission To understand the basic idea behind a standard transmission, the diagram below shows a very simple two-speed transmission in neutral: Lets look at each of the parts in this diagram to understand how they fit together: The green shaft comes from the engine throug

9、h the clutch. The green shaft and green gear are connected as a single unit. (The clutch is a device that lets you connect and disconnect the engine and the transmission. When you push in the clutch pedal, the engine and the transmission are disconnected so the engine can run even if the car is stan

10、ding still. When you release the clutch pedal, the engine and the green shaft are directly connected to one another. The green shaft and gear turn at the same rpm as the engine.) The red shaft and gears are called the layshaft. These are also connected as a single piece, so all of the gears on the l

11、ayshaft and the layshaft itself spin as one unit. The green shaft and the red shaft are directly connected through their meshed gears so that if the green shaft is spinning, so is the red shaft. In this way, the layshaft receives its power directly from the engine whenever the clutch is engaged. The

12、 yellow shaft is a splined shaft that connects directly to the drive shaft through the differential to the drive wheels of the car. If the wheels are spinning, the yellow shaft is spinning. The blue gears ride on bearings, so they spin on the yellow shaft. If the engine is off 3 but the car is coast

13、ing, the yellow shaft can turn inside the blue gears while the blue gears and the layshaft are motionless. Now, lets see what happens when you shift into first gear. First Gear In this picture, the green shaft from the engine turns the layshaft, which turns the blue gear on the right. This gear tran

14、smits its energy through the collar to drive the yellow drive shaft. Meanwhile, the blue gear on the left is turning, but it is freewheeling on its bearing so it has no effect on the yellow shaft. When the collar is between the two gears (as shown in the first figure), the transmission is in neutral

15、. Both of the blue gears freewheel on the yellow shaft at the different rates controlled by their ratios to the layshaft. From this discussion, you can answer several questions: When you make a mistake while shifting and hear a horrible grinding sound, you are not hearing the sound of gear teeth mis

16、-meshing. As you can see in these diagrams, all gear teeth are all fully meshed at all times. The grinding is the sound of the dog teeth trying unsuccessfully to engage the holes in the side of a blue gear. The transmission shown here does not have synchros (discussed later in the article), so if yo

17、u were using this transmission you would have to double-clutch it. Double-clutching was common in older cars and is still common in some modern race cars. In double-clutching, you first push the clutch pedal in once to disengage the engine from the transmission. This takes the pressure off the dog t

18、eeth so you can move the collar into neutral. Then you release the clutch pedal and rev the engine to the right speed. The right speed is the rpm value at which the engine should be running in the next gear. The idea is to get the blue gear of the next gear and the collar rotating at the same speed

19、so that the dog teeth can engage. Then you push the clutch pedal in again and lock the collar into the new gear. At every gear change you have to press and release the clutch twice, hence the name double-clutching. You can also see how a small linear motion in the gear shift knob allows you to chang

20、e gears. The gear shift knob moves a rod connected to the fork. The fork slides the collar on the yellow shaft to engage one of two gears. In the next section, well take a look at a real transmission. A Real Transmission 4 There are three forks controlled by three rods that are engaged by the shift

21、lever. Looking at the shift rods from the top, they look like this in reverse, first and second gear: Keep in mind that the shift lever has a rotation point in the middle. When you push the knob forward to engage first gear, you are actually pulling the rod and fork for first gear back. You can see

22、that as you move the shifter left and right you are engaging different forks (and therefore different collars). Moving the knob forward and backward moves the collar to engage one of the gears。 Reverse gear is handled by a small idler gear (purple). At all times, the blue reverse gear in this diagra

23、m is turning in a direction opposite to all of the other blue gears. Therefore, it would be impossible to throw the transmission into reverse while the car is moving forward - the dog teeth would never engage. However, they will make a lot of noise! 5 手动变速器如何工作 如果你驾驶一台手动小轿 车，那么你可能会有几个问题漂浮在脑海中。 当移动换挡

24、操纵杆时，是怎样通过变速器中齿轮的联系实现有趣的 “H”模式？当我移动操纵杆时，变速器里面是如何工作的呢？ 当我换错挡并听到可怕的摩擦声时，实际是什么在磨削呢？如果我在高速公路上急行时，突然换倒档会发生什么情况呢？变速器会爆炸吗？ 在本篇文章中，我们将回答所有这些问题，更要探索手动变速器内部。 由于物理学的汽油发动机，故汽车需要传输动力。首先，任何发动机都有一条红界限 转速超过最大值时，发动机不会运行也不会爆炸。第二，如果你知道马力是如何工作的，那么你一定 知道当马力和扭矩达到最大值时，发动机的转速范围缩小。例如，发动机可能产生的最大马力为 5500转。变速器使发动机和驱动车轮之间的传动比变小

25、，以使汽车加速行驶。你变速行驶时，发动机能停留在红界限或界限附近以达到最佳行驶状态。 最理想的是，变速器以非常灵活的比率使发动机可以始终运行在单一的、最高性能的转速。这种想法基于连续的变速传动（无级变速器）。 无级变速器有近无穷的传动比范围。在过去，无级变速器在成本、大小和可靠性上不能与四档和五档变速器相比，所以没有大量运用于汽车生产中。近年来，无级变速器的改进设计更为常见 。丰田普锐斯是一辆使用无级变速器的混合动力型汽车。 变速器通过离合器与发动机相连。因此，变速器输入轴与发动机以同样的转速转动。 五档变速器适用于五个不同的传动比的汽车，它把输入轴产生的不同转速值传给输出轴。 一个非常简单的

26、变速器 为了理解一台标准变速器的原理，下面的图表显示了一个非常简单的中间轴式双速传动变速器： 让我们看一看图表中的每一部分，理解他们是怎样结合在一起的：发动机的动力通过离合器传给输入轴。输入轴和输入齿轮以一个单个单元连接。（离合器是一种装置，它可以连接和断开发动机和变速器。当你踏下离合器踏 板时，发动机和离合器不连接，所以即使汽车停着不动，发动机也能运行。当你释放离合器踏板时，发动机与输入轴直接相连。输入轴与输出轴的转速与发动机相同。） 红色轴和齿轮被称为中间轴。这也是作为一个单一的连接件，所以所有的中间轴 6 齿轮和其本身自旋为一个单元。输入轴和中间轴通过啮合齿轮直接相连，因此如果输入轴旋转

27、，中间轴也旋转。这样，当离合器工作时，中间轴收到的动力直接来自发动机。 黄色轴是花键轴，它通过汽车上不同传动齿轮与中间轴相连接。如果齿轮旋转，输出轴也跟着旋转。 蓝色齿轮套在轴承上，所以可以在输出轴上旋转。如果 发动机停转而汽车滑行时，当输出轴齿轮与中间轴静止不动时，输出轴能在其齿轮中旋转。 现在，让我们看一看一挡工作过程。 一挡 图中，输入轴把来自发动机的动力传给中间轴，通过向右推动蓝色齿轮完成一挡传动。齿轮通过啮合套传递动力给输出轴，与此同时，输出轴左侧蓝齿轮也旋转，但是他是在轴承上空转所以对输出轴没有影响。 当啮合套在中间时，变速器处于空挡。两个齿轮在输出轴上被中间轴控制以不同的传动速比

28、。 从这次讨论中，你可以回答几个问题： 当你犯了一个错误挂错挡并听到可怕的磨削声时，你听到的只是齿轮错误啮合的声音。正如你看 到的图表一样，所有的齿轮一直是啮合的。磨削声是齿轮在蓝色齿轮内部没有正确使用造成的。 这里显示的变速器没有同步器，因此，如果你使用这样的传输机构，那么你应该使用双向离合器。双向离合器在过去的轿车中常见，并且现代的赛车中也很常见。离合器双向控制中，你首先踩下离合器踏板来分离变速器与发动机之间的动力。这样脱离了齿轮上的压力，便可以把啮合套移动到中间位置。然而，当你释放离合器踏板，使发动机转速为 “合适的速度 ”。合适的速度是在发动机运行于齿轮下每分钟适宜的转速值。这样是使蓝

29、色齿轮和啮合齿轮以同一转速旋转，因此，啮合 齿可以工作。然后，再次踩下离合器踏板，并锁止在新齿轮上。每一次齿轮传动变化时，你将踩下并释放离合器两次，因此得名 “双向离合器 ”。 你还可以看到一个小型的直线运动的齿轮换挡操纵杆，可以让你变更齿轮。操纵杆移动一支杆来连接拨叉，拨叉滑动啮合套来控制输出轴上的两个齿轮。 在下一节，我们将看一下真正的变速器。 实时传输 三个拨叉轴控制换挡拨叉使操纵杆工作。看一下顶端的拨叉轴，它们像这样旋转，控制第一齿轮和第二齿轮： 7 记住换挡操纵杆的旋转点在中间。当你向前推动拨块换入一挡，实际上是拉动操纵杆拨叉使一挡齿轮旋转。 你可 以认为这是你向左和向右移动操纵杆来控制不同的拨叉（因此啮合套不同）。向前和向后移动拨块使其中一对齿轮工作。 倒档齿轮是一个小惰性轮。在任何时候，图中蓝色倒档齿轮是在一个方向转向对面的所有其他蓝色齿轮。因此，当汽车向前行驶时就不可能把传输逆转。然而，它们将会制造很大的噪音！