汽车制动系统中英文对照外文翻译文献

1、 汽车制动系统中英文对照外文翻译文献汽车制动系统中英文对照外文翻译文献(文档含英文原文和中文翻译)Brake systemsWe all know that pushing down on the brake pedal slows a car to a stop. But howdoes this happen? How does your car transmit the force from your leg to its wheels? Howdoes it multiply the force so that it is enough to stop something as big

2、 as a car?Brake Image Gallery 汽车制动系统中英文对照外文翻译文献Layout of typical brake system. See more brake images.When you depress your brake pedal, your car transmits the force from your foot to itsbrakes through a fluid. Since the actual brakes require a much greater force than youcould apply with your leg, yo

3、ur car must also multiply the force of your foot. It does this intwo ways:Hydraulic force multiplicationThe brakes transmit the force to the tires usingfriction, and the tires transmit thatforce to the road using friction also. Before we begin our discussion on the components ofthe brake system, wel

4、l cover these three principles:LeverageHydraulicsFrictionLeverage and HydraulicsIn the figure below, a force F is being applied to the left end of the lever. The left endof the lever is twice as long (2X) as the right end (X). Therefore, on the right end of thelever a force of 2F is available, but i

5、t acts through half of the distance (Y) that the left endmoves (2Y). Changing the relative lengths of the left and right ends of the lever changesthe multipliers. 汽车制动系统中英文对照外文翻译文献The pedal is designed in such a way that it can multiply the force from yourleg several times before any force is even t

6、ransmitted to the brake fluid.The basic idea behind any hydraulic system is very simple: Force applied at onepoint is transmitted to another point using an incompressible fluid, almost always an oilof some sort. Most brake systems also multiply the force in the process. Here you can seethe simplest

7、possible hydraulic system:Your browser does not support JavaScript or it is disabled.Simple hydraulic systemIn the figure above, two pistons (shown in red) are fit into two glass cylinders filledwith oil (shown in light blue) and connected to one another with an oil-filled pipe. If youapply a downwa

8、rd force to one piston (the left one, in this drawing), then the force istransmitted to the second piston through the oil in the pipe. Since oil is incompressible, theefficiency is very good - almost all of the applied force appears at the second piston. Thegreat thing about hydraulic systems is tha

9、t the pipe connecting the two cylinders can beany length and shape, allowing it to snake through all sorts of things separating the two 汽车制动系统中英文对照外文翻译文献pistons. The pipe can also fork, so that onemaster cylinder can drive more than one slavecylinder if desired, as shown in here:Master cylinder with

10、 two slavesThe other neat thing about a hydraulic system is that it makes force multiplication (ordivision) fairly easy. If you have read How a Block and Tackle Works or How Gear RatiosWork, then you know that trading force for distance is very common in mechanicalsystems. In a hydraulic system, all

11、 you have to do is change the size of one piston andcylinder relative to the other, as shown here:Hydraulic multiplicationTo determine the multiplication factor in the figure above, start by looking at the sizeof the pistons. Assume that the piston on the left is 2 inches (5.08 cm) in diameter (1-in

12、ch /2.54 cm radius), while the piston on the right is 6 inches (15.24 cm) in diameter (3-inch /7.62 cm radius). The area of the two pistons is Pi * r2. The area of the left piston istherefore 3.14, while the area of the piston on the right is 28.26. The piston on the right isnine times larger than t

13、he piston on the left. This means that any force applied to theleft-hand piston will come out nine times greater on the right-hand piston. So, if you applya 100-pound downward force to the left piston, a 900-pound upward force will appear onthe right. The only catch is that you will have to depress

14、the left piston 9 inches (22.86 cm)to raise the right piston 1 inch (2.54 cm).A Simple Brake SystemBefore we get into all the parts of an actual car brake system, lets look at a simplifiedsystem: 汽车制动系统中英文对照外文翻译文献You can see that the distance from the pedal to the pivot is four times the distancefro

15、m the cylinder to the pivot, so the force at the pedal will be increased by a factor of fourbefore it is transmitted to the cylinder.You can also see that the diameter of the brake cylinder is three times the diameterof the pedal cylinder. This further multiplies the force by nine. All together, thi

16、s systemincreases the force of your foot by a factor of 36. If you put 10 pounds of force on thepedal, 360 pounds (162 kg) will be generated at the wheel squeezing the brake pads.There are a couple of problems with this simple system. What if we have aleak? If itis a slow leak, eventually there will

17、 not be enough fluid left to fill the brake cylinder, and thebrakes will not function. If it is a major leak, then the first time you apply the brakes all ofthe fluid will squirt out the leak and you will have complete brake failure.Drum brakes work on the same principle as disc brakes:Shoes press a

18、gainst aspinning surface. In this system, that surface is called a drum. 汽车制动系统中英文对照外文翻译文献Figure 1. Location of drum brakes. See more drum brakepictures.Many cars have drum brakes on the rear wheels and disc brakes on the front. Drumbrakes have more parts than disc brakes and are harder to service,

19、but they are lessexpensive to manufacture, and they easily incorporate an emergency brake mechanism.In this edition of HowStuffWorks, we will learn exactly how a drum brake systemworks, examine the emergency brake setup and find out what kind of servicing drumbrakes need.Figure 2. Drum brake with dr

20、um in place 汽车制动系统中英文对照外文翻译文献Figure 3. Drum brake without drum in placeLets start with the basics.The drum brake may look complicated, and it can be pretty intimidating when youopen one up. Lets break it down and explain what each piece does.Figure 4. Parts of a drum brakeLike the disc brake, the dr

21、um brake has two brake shoes and a piston. But the drumbrake also has an adjuster mechanism, an emergency brake mechanism and lots ofsprings.First, the basics: Figure 5 shows only the parts that provide stopping power. 汽车制动系统中英文对照外文翻译文献Your browser does not support JavaScript or it is disabled.Figur

22、e 5. Drum brake in operationWhen you hit the brake pedal, the piston pushes the brake shoes against the drum.Thats pretty straightforward, but why do we need all of those springs?This is where it gets a little more complicated. Many drum brakes areself-actuating.Figure 5 shows that as the brake shoe

23、s contact the drum, there is a kind of wedging action,which has the effect of pressing the shoes into the drum with more force.The extra braking force provided by the wedging action allows drum brakes to use asmaller piston than disc brakes. But, because of the wedging action, the shoes must bepulle

24、d away from the drum when the brakes are released. This is the reason for some ofthe springs. Other springs help hold the brake shoes in place and return the adjuster armafter it actuates.For the drum brakes to function correctly, the brake shoes must remain close to thedrum without touching it. If

25、they get too far away from the drum (as the shoes wear down,for instance), the piston will require more fluid to travel that distance, and your brake pedalwill sink closer to the floor when you apply the brakes. This is why most drum brakes havean automatic adjuster. 汽车制动系统中英文对照外文翻译文献Figure 6. Adjus

26、ter mechanismNow lets add in the parts of the adjuster mechanism. The adjuster uses theself-actuation principle we discussed above.Your browser does not support JavaScript or it is disabled.In Figure 7, you can see that as the pad wears down, more space will form betweenthe shoe and the drum. Each t

27、ime the car stops while in reverse, the shoe is pulled tightagainst the drum. When the gap gets big enough, the adjusting lever rocks enough toadvance the adjuster gear by one tooth. The adjuster has threads on it, like a bolt, so thatit unscrews a little bit when it turns, lengthening to fill in th

28、e gap. When the brake shoeswear a little more, the adjuster can advance again, so it always keeps the shoes close tothe drum.Some cars have an adjuster that is actuated when the emergency brake is applied.This type of adjuster can come out of adjustment if the emergency brake is not used for 汽车制动系统中

29、英文对照外文翻译文献long periods of time. So if you have this type of adjuster, you should apply youremergency brake at least once a week.ServicingThe most common service required for drum brakes ischanging the brake shoes.Some drum brakes provide an inspection hole on the back side, where you can see howmuch

30、 material is left on the shoe. Brake shoes should be replaced when the frictionmaterial has worn down to within 1/32 inch (0.8 mm) of the rivets. If the friction material isbonded to the backing plate (no rivets), then the shoes should be replaced when theyhave only 1/16 inch (1.6 mm) of material le

31、ft.Photo courtesy of a local AutoZone storeFigure 9. Brake shoeJust as in disc brakes, deep scores sometimes get worn into brake drums. If aworn-out brake shoe is used for too long, the rivets that hold the friction material to thebacking can wear grooves into the drum. A badly scored drum can somet

32、imes be repairedby refinishing. Where disc brakes have a minimum allowable thickness, drum brakes havea maximum allowable diameter. Since the contact surface is the inside of the drum, asyou remove material from the drum brake the diameter gets bigger.Figure 10. Brake drum 汽车制动系统中英文对照外文翻译文献制动系统众所周知，

33、踩下制动踏板可以使汽车减速至停止。但这是如何产生的呢？汽车是如何将力从你的腿传递到车轮的呢？汽车是如何将力放大到足够大以致可以将像汽车一样大的东西制动的呢？制动系统组件当你踩下制动踏板的时候，汽车通过液体把力从脚传递到制动器。因为制动器需要的真正力量比你的腿能提供的要大的多，所以汽车必须放大脚产生的力有两种方式：机械杠杆作用液力放大制动器通过摩擦把力传递给轮胎，并且轮胎也是通过摩擦把力传递给路面的。 在我们讨论制动系统的组成之前，先来介绍以下三条原则：杠杆液力摩擦力杠杆和液力在下面的图中，一个力F 加在杠杆的左端。左端的杠杆长度（2X）是右端（X）的两倍。因此杠杆右端可施加的力为 2F ，但是

34、右端移动的距离(Y)是左端距离(2Y)的一半。改变杠杆的左端和右端的长度可以改变放大系数。 汽车制动系统中英文对照外文翻译文献任何液压系统背后的基本原理都是非常简单的：作用在某一点力通过通常是油一类的不可压缩的液体传递到另一点。大多数的制动系统也在这个过程中放大力。下面的是最简单的液压系统：简单液压系统在上图中，两个活塞放在两个充满油的玻璃液压缸中并且由充满油的管道相连。如果在一个活塞上施加一个向下的力，那么力将通过管道中的油传递到第二个活塞。因为油液是不可压缩的，所以传递效率很好，大部分的作用力都传递到了另一个活塞。液压系统的好处连接两液压缸的管道可以是任何长度和形状，这样就可以使管道弯曲的

35、通过两活塞之间的各种部件。管道也可以是分叉的，如果有需要的话，这样一个主缸可以驱动数个副缸。如下图所示：带有两个副缸的主缸液压系统的另一个好处是产生放大（或者缩小） 力相当地容易。如果你一读过滑车设备工作原理或者齿轮齿数比原理，那么你就会知道在机械系统中把力转化为距离处理是很常见的。在液压系统中，我们所要做的就是相对地改变一组活塞和液压缸的尺寸。如下图所示： 汽车制动系统中英文对照外文翻译文献液压增力原理为了确定上图中的放大因子，先由观察活塞的尺寸开始。假设左边活塞的直径为 2英尺（5.08cm 而右边的直径为 6 英尺（15.24cm）。两个活塞的面积是Pi * r 。因此2左面活塞的面积是

36、 3.14，而右面的面积是 28.26。右面活塞的面积是左边的九倍大。这就意味着无论在左面的活塞上施加多大的力，在右面的活塞上就会输出九倍于左面的力。所以，如果在左边活塞上施加 100 磅向下的力，那么在右面活塞上将产生 900 磅向上的力。唯一的补偿是左面的活塞要移动 9 英尺（22.86cm）来使右面提升 1 英尺（2.54cm）一个简单的制动系统在我们深入了解一个真实的制动系统的各部分之前，让我们先来看一个简化的系统： 汽车制动系统中英文对照外文翻译文献我们可以看到踏板到枢轴的距离是液压缸到枢轴距离的 4 倍，所以施加在踏板上的力在传递到液压缸之前将被增加 4 倍。我们还可以看到制动缸的

37、直径是踏板缸直径的 3倍。这就将力进一步放大了九倍。最终这个系统将腿上的力增加了36 倍。所以，如果在踏板上施加 10 磅的力，将在挤压制动带的轮上产生369 磅（162kg）的力。下面是这种简单系统所存在的问题。要是系统有泄漏该怎么办呢？如果是轻微泄漏，最终将会没有足够的油使制动缸充满，并且制动器将停止工作。如果是严重泄漏，那么在你制动的第一时间，所有的油液将从泄露处喷射而出，并且制动系统将彻底地不起作用。鼓式制动器的工作原理和盘式制动器是一样的：制动面接触一个磨砂的表面。在这个系统中，那个表面称作制动鼓图 1.制动鼓的位置许多汽车的后轮安装鼓式制动器，而盘式制动器安装在前面。鼓式制动器比盘式制动器有更多的零件并且更难检修。 但是制造成本相对便宜，还有鼓式制动器容易组装一个紧急使用的制动装置。在本版本的 How StuffWorks 中，我们将详尽了解鼓式制动系统是如何工作的。考察紧急制动系统的组成，并且找到鼓式制动器需要何种