車輛工程外文翻譯---制動(dòng)系統(tǒng)

1、<p><b>　　附 錄1</b></p><p>　　Brake Systems</p><p>　　1.Drum vs. Disc</p><p>　　Brake technology, just like suspension technology and fuel-system technology, has come a

2、long way in recent years.</p><p>　　1）Drum Brakes</p><p>　　Early automotive brake systems, after the era of hand levers of course, used a drum design at all four wheels. They were called drum bra

3、kes because the components were housed in a round drum that rotated along with the wheel. Inside was a set of drum that, when the brake pedal was pressed, would force the shoes against the drum and slow the wheel. Fluid

4、was used to transfer the movement of the brake pedal into the movement of the brake shoes, while the drum themselves were made of heat-resistant</p><p>　　This basic design proved capable under most circumsta

5、nces, but it had one major flaw. Under high braking conditions, like descending a steep hill with a heavy load or repeated high-speed slow downs, drum brakes would often fade and lose effectiveness. Usually this fading w

6、as the result of too much heat build-up within the shoes. Remember that the principle of braking involves turning kinetic energy (wheelmovement) into thermal energy (heat). For this reason, drum brakes can only operate a

7、s long </p><p>　　2） Disc Brakes</p><p>　　Disc brakes are used on the front wheels of most cars and on all four wheels on many cars. A disc rotor is attached to the wheel hub and rotates with the

8、 tire and wheel. When the driver applies the brakes, hydraulic pressure from the master cylinder is used to push friction linings against the rotor to stop it.</p><p>　　In the disc brake rotor assembly, the

9、rotor is usually made of cast iron. The hub may be manufactured as one piece with the rotor or in two parts. The rotor has a machined braking surface on each face. A splash shield, mounted to the steering knuckle, protec

10、ts the rotor from road splash.</p><p>　　A rotor may be solid or ventilated. Ventilated designs have cooling fins cast between the braking surfaces. This construction considerably increases the cooling area o

11、f the rotor casting. Also, when the wheel is in motion, the rotation of these fan-type fins in the rotor provides increased air circulation and more efficient cooling of the brake. Disc brakes do not fade even after rapi

12、d, hard brake applications because of the rapid cooling of the rotor.</p><p>　　The hydraulic and friction components are housed in a caliper assembly. The caliper assembly straddles the outside diameter of t

13、he hub and rotor assembly. When the brakes are applied, the pressure of the pistons is exerted through the shoes in a 'clamping＇ action on the rotor. Because equal opposed hydraulic pressures are applied to both face

14、s of the rotor throughout application, no distortion of the rotor occurs, regardless of the severity or duration of application. There are many variations o</p><p>　　Most late-model cars use the moving calip

15、er design. This design uses a single hydraulic piston and a caliper that can float or slide during application. Floating designs｀float＇ or move on pins or bolts. In sliding designs, the caliper slides sideways on machine

16、d surfaces. Both designs work in basically the same way.</p><p>　　In the single piston floating caliper, the single-piston caliper assembly is constructed from a single casting that contains one large piston

17、 bore in the inboard section of the casting. Inboard refers to the side of the casting nearest the center line of the car when the caliper is mounted. A fluid inlet hole and bleeder valve hole are machined into the inboa

18、rd section of the caliper and connect directly to the piston bore.</p><p>　　The caliper cylinder bore contains a piston and seal. The seal has a rectangular cross section. It is located in a groove that is m

19、achined in the cylinder bore. The seal fits around the outside diameter of the piston and provides a hydraulic seal between the piston and the cylinder wall. The rectangular seal provides automatic adjustment of clearanc

20、e between the rotor and shoe and linings following each application. When the brakes are applied, the caliper seal is deflected by the hydraulic pres</p><p>　　As brake linings wear, piston travel tends to ex

21、ceed the limit of deflection of the seal; the piston therefore slides in the seal to the precise extent necessary to compensate for lining wear.</p><p>　　The top of the piston bore is machined to accept a se

22、aling dust boot. The piston in many calipers is steel, precision ground, and nickel chrome plated, giving it a very hard and durable surface. Some manufacturers are using a plastic piston. This is much lighter than steel

23、 and provides for a much lighter brake system. The plastic piston insulates well and prevents heat from transferring to the brake fluid. Each caliper contains two shoe and lining assemblies. They are constructed of a sta

24、mped me</p><p>　　The application and release of the brake pressure actually causes a very slight movement of the piston and caliper. Upon release of the braking effort, the piston and caliper merely relax in

25、to a released position. In the released position, the shoes do not retract very far from the rotor surfaces.</p><p>　　As the brake lining wears, the piston moves out of the caliper bore and the caliper repos

26、itions itself on the mounting bolts an equal distance toward the car. This way, the caliper assembly maintains the inboard and outboard shoe and lining in the same relationship with the rotor surface throughout the full

27、length of the lining.</p><p>　　Sliding calipers are made to slide back and forth on the steering knuckle support to which it is mounted. There is a V shaped surface, sometimes called a rail, on the caliper t

28、hat matches a similar surface on the steering knuckle support. These two mating surfaces allow the caliper to slide in and out. The internal components of the caliper are the same as those previously described.</p>

29、<p>　　The stationary or fixed caliper has a hydraulic piston on each side of the rotor. Larger calipers may have two pistons on each side of the rotor. The inboard and outboard brake shoes are pushed against the r

30、otor by their own pistons. The caliper is anchored solidly and does not move. The seals around the pistons work just like those already described. The main disadvantage of the stationary caliper is that it has more hydra

31、ulic components. This means they are more expensive and have more parts t</p><p>　　2.Other Components in the Hydraulic System:</p><p>　　1）Proportioning Valve or Equalizer Valve</p><p&

32、gt;　　These valves are mounted between the master cylinder and the rear wheels. They are designed to adjust the pressure between the front and rear brakes depending on how hard you are stopping. The shorter you stop, the

33、more of the vehicle’s weight is transferred to the front wheels, in some cases, causing the rear to lift and the front to dive. These valves are designed to direct more pressure to the front and less pressure to the rear

34、 the harder you stop. This minimizes the chance of premature lock</p><p>　　2）Pressure Differential Valve</p><p>　　This valve is usually mounted just below the master cylinder and is responsible

35、for turning the brake warning light on when it detects a malfunction. It measures the pressure from the two sections of the master cylinder and compares them. Since it is mounted ahead of the proportioning or equalizer v

36、alve, the two pressures it detects should be equal. If it detects a difference, it means that there is probably a brake fluid leak somewhere in the system. </p><p>　　3）Combination Valve</p><p>　

37、　The Combination valve (Figure) is simply a proportioning valve and a pressure differential valve that is combined into one unit.</p><p>　　The parking brake (a．k．a(chǎn)．emergency brake ) system controls the rear

38、brakes through a series of steel cables that are connected to either a hand lever or a foot pedal. The idea is that the system is fully mechanical and completely bypasses the hydraulic system so that the vehicle can be b

39、rought to a stop even if there is a total brake failure.</p><p>　　On drum brakes, the cable pulls on a lever mounted in the rear brake and is directly connected to the brake shoes. This has the effect of byp

40、assing the wheel cylinder and controlling the brakes directly.</p><p>　　Disk brakes on the rear wheels add additional complication for parking brake systems. There are two main designs for adding a mechanica

41、l parking brake to rear disk brakes. The first type uses the existing rear wheel caliper and adds a lever attached to a mechanical corkscrew device inside the caliper piston. When the parking brake cable pulls on the lev

42、er, this corkscrew device pushes the piston against the pads, thereby bypassing the hydraulic system, to stop the vehicle. This type of system is</p><p>　　On cars with automatic transmissions, the parking br

43、ake is rarely used. This can cause a couple of problems. The biggest problem is that the brake cables tend to get corroded and eventually seize up causing the parking brake to become inoperative. By using the parking bra

44、ke from time to time, the cables stay clean and functional. Another problem comes from the fact that the self adjusting mechanism on certain brake systems uses the parking brake actuation to adjust the brakes. If the par

45、king bra</p><p>　　The power brake booster (Figure) is mounted of the firewall directly behind the master cylinder and, along with the master cylinder, is directly connected with the brake pedal. Its purpose

46、is to amplify the available foot pressure applied to the brake pedal so that the amount of foot pressure required to stop even the largest vehicle is minimal. Power for the booster comes from engine vacuum. The automobil

47、e engine produces vacuum as a by-product of normal operation and is freely available for us</p><p>　　The last topic is the Anti-Lock Brakes (ABS). The most efficient braking pressure takes place just before

48、each wheel lock up. When you slam on the brakes in a panic stop and the wheels lock up, causing a screeching sound and leaving strips of rubber on the pavement, you do not stop the vehicle nearly as short as it is capabl

49、e of stopping. Also, while the wheels are locked up, you loose all steering control so that , if you have an opportunity to steer around the obstacle, you will not be able to</p><p>　　Anti-lock brake systems

50、 solve this lockup problem by rapidly pumping the brakes whenever the system detects a wheel that is locked up. In most cases, only the wheel that is locked will be pumped, while full braking pressure stays available to

51、the other wheels. This effect allows you to stop in the shortest amount of time while maintaining full steering control even if one or more wheels are on ice. The system uses a computer to monitor the speed of each wheel

52、. When it detects that one or more wh</p><p>　　The system consists of am electronic control unit, a hydraulic actuator, and wheel speed sensors at each wheel. If the control unit detects a malfunction in the

53、 system, it will illuminate an ABS warming light on the dash to let you know that there is a problem. If there is a problem, the antilock system will not function but the brakes will otherwise function normally.</p>

54、;<p>　　3.Friction materials</p><p>　　Brake shoes and pads are constructed in a similar manner. The pad or shoe is composed of a metal backing plate and a friction lining. The lining is either bonded (

55、glued) to the metal, or riveted. Generally, riveted linings provide superior performance, but good quality bonded linings are perfectly adequate.</p><p>　　Friction materials will vary between manufacturers a

56、nd type of pad and the material compound may be referred to as: asbestos, organic, semi-metallic, metallic. The difference between these compounds lies in the types and percentages of friction materials used, material bi

57、nders and performance modifiers.</p><p>　　Generally speaking, organic and non-metallic asbestos compound brakes are quiet, easy on rotors and provide good feel. But this comes at the expense of high temperat

58、ure operation, so they may not be your best choice for heavy duty use or mountain driving. In most cases, these linings will wear somewhat faster than metallic compound pads, so you will usually replace them more often.

59、But, when using these pads, rotors tend to last longer.</p><p>　　Semi-metallic or metallic compound brake linings will vary in performance based on the metallic contents of the compound. Again, generally spe

60、aking, the higher the metallic content, the better the friction material will resist heat. This makes them more appropriate for heavy duty applications, but at the expense of braking performance before the pad reaches op

61、erating temperature. The first few applications on a cold morning may not give strong braking. Also, metallic and semi-metallic are more l</p><p>　　When deciding what type of brake lining is right for you, k

62、eep in mind that today's modern cars have brake materials which are matched to the expected vehicle＇s performance capabilities. Changing the material from OEM specification could adversely affect brake feel or respon

63、siveness. Before changing the brake materials, talk to your dealer or parts supplier to help decide what is most appropriate for your application. Remember that heavy use applications such as towing, stop and go driving,

64、 driv</p><p>　　Some more exotic materials are also used in brake linings, among which are Kevlar and carbon compounds. These materials have the capability of extremely good performance for towing, mountain d

65、riving or racing. Wear characteristics can be similar to either the metallic or the non-metallic linings, depending on the product you buy. Most race applications tend to wear like metallic linings, while many of the str

66、eet applications are more like the non-metallic</p><p><b>　　制動(dòng)系統(tǒng)</b></p><p><b>　　1. 剎車：鼓與盤</b></p><p>　　制動(dòng)技術(shù)，就像懸浮技術(shù)和燃料系統(tǒng)技術(shù)，已走過了漫長(zhǎng)的道路</p><p><

67、b>　　1）鼓式制動(dòng)器</b></p><p>　　早在后時(shí)代，手杠桿的汽車制動(dòng)系統(tǒng)用鼓裝在所有的四個(gè)車輪。它們被稱為鼓式制動(dòng)器的組成部分，因?yàn)檠b在圓鼓上，隨著車輪旋轉(zhuǎn)。里面是一套系統(tǒng)，當(dāng)剎車踏板被按下時(shí)，會(huì)迫使系統(tǒng)對(duì)鼓和車輪速度減緩。流體被用來促使剎車踏板到運(yùn)動(dòng)的制動(dòng)系統(tǒng)的運(yùn)動(dòng)，而所用的離合器片本身與一個(gè)耐熱摩擦材料相似，。 </p><p>　　這一基本設(shè)計(jì)能力的表明

68、，在大多數(shù)情況下，它有一大缺陷。高壓下的制動(dòng)條件，想在陡峭的山上降低沉重的負(fù)荷或反復(fù)高的速度緩慢，鼓式制動(dòng)器往往會(huì)褪色，失去效力。通常這褪色是由于太多的熱量累積與鼓。記得的原則，涉及制動(dòng)轉(zhuǎn)向動(dòng)能（車輪運(yùn)動(dòng)）到熱能（熱） 。基于這個(gè)原因，鼓式制動(dòng)器的操作，他們能吸收產(chǎn)生的熱量可以減緩車輛的車輪?？捎辛钊瞬话仓?，一旦制動(dòng)元件本身飽和，他們失去停止車輛的能力。</p><p><b>　　盤式制動(dòng)器<

69、/b></p><p>　　盤式制動(dòng)器用于大多數(shù)車的前輪和一些車的四個(gè)輪子。制動(dòng)盤依附于輪轂上，隨輪胎一起轉(zhuǎn)動(dòng)。當(dāng)司機(jī)剎車時(shí)，主缸的液壓用于推動(dòng)摩擦襯料，制動(dòng)鉗夾緊制動(dòng)盤，從而使車停下來。</p><p>　　在盤式制動(dòng)器中，制動(dòng)盤通常由鑄鐵構(gòu)成。轂可以被制造成一片，和車輪在一起；或者分成兩部分。盤式制動(dòng)器的每一個(gè)面都有機(jī)械閘。一塊保護(hù)板連接在轉(zhuǎn)向裝置上，以防轉(zhuǎn)子受到公路磨損。盤式制

70、動(dòng)器可以是全封閉的，也可能是中空的。中空的制動(dòng)器在閘與閘表面之間有冷卻的鑄件。這種結(jié)構(gòu)增加了制動(dòng)器鑄件的冷卻面積。當(dāng)制動(dòng)鼓移動(dòng)時(shí)，盤式制動(dòng)器中風(fēng)扇的轉(zhuǎn)動(dòng)增加了空氣循環(huán)和制動(dòng)的冷卻效率。由于盤式制動(dòng)器的冷卻效能，即便要求苛刻，盤式制動(dòng)器也不會(huì)被淘汰。</p><p>　　液壓和摩擦部分集中在一個(gè)制動(dòng)鉗。制動(dòng)鉗集中跨越轂和制動(dòng)盤的直徑外部。當(dāng)制動(dòng)閘啟用，活塞的壓力通過夾鉗的蹄片作用制動(dòng)盤。由于同樣的液壓通過施用作用在

71、制動(dòng)盤的兩面，制動(dòng)盤不會(huì)由于施用的激烈或耐久而出現(xiàn)變形。制動(dòng)鉗的設(shè)計(jì)多種多樣，但通常由兩種主要類型：浮鉗盤式和定鉗盤式。定鉗盤是固定安裝在車橋上，浮鉗盤式是可以旋轉(zhuǎn)也可以沿制動(dòng)盤軸線方向移動(dòng)。</p><p>　　許多新型汽車采用浮鉗盤式制動(dòng)器設(shè)計(jì)。這種設(shè)計(jì)采用一個(gè)液壓活塞和一個(gè)制動(dòng)鉗，使其能夠在施用時(shí)飄移和滑動(dòng)。飄移設(shè)計(jì)在圖釘或螺柱上“飄移”。在滑動(dòng)設(shè)計(jì)中，卡鉗在機(jī)器表面滑動(dòng)。這兩種設(shè)計(jì)基本上以同樣的方式起作用

72、。</p><p>　　在單活塞飄移卡鉗中，單活塞卡鉗集中來源于一個(gè)單獨(dú)的鑄件。此鑄件包含鑄件內(nèi)側(cè)一個(gè)大活塞孔，內(nèi)側(cè)指的是當(dāng)卡鉗發(fā)動(dòng)時(shí)汽車中心線附近的鑄件一側(cè)。流體入口的洞和分壓閘門洞都在卡鉗的內(nèi)側(cè)，直接與活塞口相連。</p><p>　　制動(dòng)鉗氣缸包括一個(gè)活塞和封口。封口有一個(gè)矩形十字部分。這一部分在氣缸的一個(gè)槽里。這個(gè)封口在活塞直徑外圍，在活塞和氣缸之間提供一個(gè)液壓封口。這個(gè)矩形封口通

73、過分次施用自動(dòng)調(diào)節(jié)，清理制動(dòng)盤，蹄片和連接之間的部分。當(dāng)制動(dòng)器施用，制動(dòng)鉗封口就會(huì)由于液壓和氣缸槽里的活塞內(nèi)直徑偏離方向。當(dāng)液壓釋放，封口釋放，并回到它原始的矩形，當(dāng)活塞作用于氣缸內(nèi)從而清理其內(nèi)部。</p><p>　　制動(dòng)鉗襯料磨損，活塞開始運(yùn)動(dòng)使封口偏離；活塞因此在封口中滑動(dòng)以補(bǔ)償襯料磨損。</p><p>　　活塞的頂端有一個(gè)封口灰塵裝置。許多制動(dòng)鉗里的活塞都是鋼材料，精確的底面，鉻

74、板制成，表面堅(jiān)硬耐久。有些大規(guī)模制造中用塑料活塞。這種材質(zhì)比鋼輕，提供一個(gè)較輕的制動(dòng)閘系統(tǒng)。這種塑料活塞，絕緣性好，防止熱氣傳輸?shù)街苿?dòng)液中。每個(gè)制動(dòng)鉗包括兩個(gè)蹄片和一些襯料。他們由一個(gè)金屬踏板蹄片，襯料由蹄片鉚接在轉(zhuǎn)子一邊的制動(dòng)鉗上。一個(gè)蹄片和一些襯料叫做內(nèi)側(cè)襯料，因?yàn)樗谲囍行木€的附近。另一個(gè)邊由外側(cè)蹄片和襯料組成。</p><p>　　制動(dòng)器的施用和釋放引起了活塞和制動(dòng)鉗的輕微運(yùn)動(dòng)。在制動(dòng)器的釋放作用下，活塞

75、和制動(dòng)鉗處于釋放位置。在釋放位置，蹄片作用時(shí)離制動(dòng)盤表面不遠(yuǎn)。當(dāng)制動(dòng)襯料磨損時(shí)，活塞脫離制動(dòng)鉗，制動(dòng)鉗回到和插銷與車距離相同的位置。這樣，制動(dòng)鉗集中在蹄片的內(nèi)外側(cè)，襯料通過線路的長(zhǎng)度和轉(zhuǎn)子表面有相同的關(guān)系。</p><p>　　2.液力制動(dòng)系的其它部分:</p><p><b>　　比例閥或平衡閥</b></p><p>　　這種閥安裝在主缸和

76、后輪之間。這些閥用于調(diào)節(jié)分配到前后輪制動(dòng)管路的油壓，而這些壓力的大小取決于駕駛員制動(dòng)的強(qiáng)度。制動(dòng)越急促，則汽車的重心越靠近前輪，有些情況下，甚至能導(dǎo)致后輪抬起，出現(xiàn)點(diǎn)頭現(xiàn)象。這些閥的設(shè)計(jì)用來更正前輪壓力，減少后輪壓力使車很難停下來。這樣可以減少后輪被鎖死的機(jī)率。</p><p><b>　　差壓閥</b></p><p>　　這種閥通常安裝于主缸的下面，當(dāng)它檢測(cè)到故障

77、時(shí)，這種閥就能打開制動(dòng)警</p><p>　　示燈。它會(huì)測(cè)量來自主缸兩部分的壓力并且比較它們。因?yàn)樗惭b在平衡閥和比例閥的前面，它檢測(cè)到的兩個(gè)壓力應(yīng)該是相等的。如果檢測(cè)到的壓力不同，那就是說系統(tǒng)中某部分的制動(dòng)液泄漏。</p><p><b>　　組合閥</b></p><p>　　如圖所示的組合閥。就是比例閥和差壓閥組合成的一個(gè)整體。</

78、p><p>　　駐車制動(dòng)（有稱應(yīng)急制動(dòng)）系統(tǒng)通過一套與操縱手柄或踏板相連的鋼纜來操縱后輪制動(dòng)器。這套系統(tǒng)是機(jī)械式的，且與液壓系統(tǒng)并聯(lián)，從而保證在整個(gè)液壓制動(dòng)系統(tǒng)失靈的情況下汽車也能實(shí)現(xiàn)制動(dòng)。</p><p>　　在鼓式制動(dòng)器中，安裝在后輪制動(dòng)器上的鋼纜直接與制動(dòng)蹄相連。它具有使車輪輪缸旁路和間接控制制動(dòng)器的作用。</p><p>　　安裝在后輪的盤式制動(dòng)器增加了制動(dòng)系統(tǒng)

79、的復(fù)雜性。這其中的兩個(gè)主要設(shè)計(jì)為的是增加后部盤式制動(dòng)器的機(jī)械制動(dòng)性。第一種是應(yīng)用現(xiàn)有的后輪卡鉗，對(duì)卡鉗活塞里面的機(jī)械螺絲錐加一個(gè)控制桿。當(dāng)制動(dòng)纜線拉動(dòng)控制桿時(shí)，這個(gè)螺旋裝置就推動(dòng)活塞作用于踏板，從而旁路掉液壓系統(tǒng)，使車停下來。這種制動(dòng)系主要用單活塞浮動(dòng)卡鉗，如果卡鉗是四活塞固定式，那么這個(gè)系統(tǒng)不能用。其它系統(tǒng)應(yīng)用一個(gè)安裝在輪子后方的完整的制動(dòng)鼓或制動(dòng)蹄單元。這個(gè)系統(tǒng)中的制動(dòng)蹄與控制桿連接著被駐車制動(dòng)拉動(dòng)著產(chǎn)生制動(dòng)。制動(dòng)鼓事實(shí)上是后部制動(dòng)

80、轉(zhuǎn)子的一部分。</p><p>　　制動(dòng)自動(dòng)變速器制動(dòng)停車很少使用。這樣勢(shì)必造成兩個(gè)問題。最大的問題是剎車?yán)|線往往受到銹蝕，并最終導(dǎo)致制動(dòng)失效。經(jīng)常使用制動(dòng)停車保持纜線清潔功能正常。另一個(gè)問題是自我調(diào)節(jié)機(jī)構(gòu)，對(duì)一些制動(dòng)系統(tǒng)利用停車制動(dòng)驅(qū)動(dòng)調(diào)整制動(dòng)器。如果停車制動(dòng)器是從未使用過，那么剎車永遠(yuǎn)得不到調(diào)整。</p><p>　　電力制動(dòng)助力器直接安裝在位于主缸后面的殼體上，與主缸一起直接連接著制

81、動(dòng)踏板。目的是對(duì)制動(dòng)蹄施加可能的壓力為的是哪怕是最大的車可以用最小的力使它停下來。助力器的力來源于發(fā)動(dòng)機(jī)的真空。汽車發(fā)動(dòng)機(jī)產(chǎn)生的真空作為正常運(yùn)作下可以免費(fèi)應(yīng)用作為動(dòng)力配件。比如電力助力系統(tǒng)。真空通過助力器中的止回閥進(jìn)入到助力器中。止回閥是通過一系列的橡膠軟管連接著發(fā)動(dòng)機(jī)，并作為一個(gè)單向閥使空氣進(jìn)入助力器。助力器是一個(gè)空殼被一個(gè)橡膠膜分為兩個(gè)腔。當(dāng)腳離開制動(dòng)踏板時(shí)這個(gè)閥仍然開著為的是兩個(gè)腔都可以被充滿。當(dāng)踩下制動(dòng)踏板時(shí)，閥門膜片關(guān)閉，分開

82、兩個(gè)腔，而另一個(gè)閥打開使空氣進(jìn)入到制動(dòng)踏板一側(cè)的腔里。這樣就提供了助力。動(dòng)力助力器非?？煽?，本身很少出現(xiàn)問題。然而，其它東西可以導(dǎo)致動(dòng)力助力的損耗。為了得到動(dòng)力助力，發(fā)動(dòng)機(jī)必須運(yùn)轉(zhuǎn)。如果在你駕駛時(shí)發(fā)動(dòng)機(jī)關(guān)閉或不運(yùn)轉(zhuǎn)，你必須有兩個(gè)或三個(gè)踏板的小型后備助力裝置，盡管如此，制動(dòng)也會(huì)很難實(shí)施，你必須施加盡可能大的力量才能使車停下來。</p><p>　　最后的主題就是ABS。發(fā)生在每個(gè)車輪鎖死之前最有效的制動(dòng)壓力。當(dāng)你在

83、慌亂中急剎車而車輪鎖死時(shí)，就會(huì)發(fā)出一聲慘叫并在路面上留有橡膠拖印，基本上不能在很短的時(shí)間內(nèi)將車停下來。而且當(dāng)車輪鎖死時(shí)，你失去了所有的轉(zhuǎn)向控制，即使你有機(jī)會(huì)繞過障礙物你也做不到了。另一個(gè)情況就是發(fā)生在打滑時(shí)，就是燃燒輪胎上的一小片橡膠形成胎面平點(diǎn)，所以在駕駛時(shí)產(chǎn)生一個(gè)極大的聲音。</p><p>　　汽車防抱死系統(tǒng)就是系統(tǒng)檢測(cè)到車輪被鎖時(shí)通過快速的提供電磁泵來解決這種被鎖問題。在大多數(shù)情況下，只有被鎖的車輪才能提

84、供，而充足的制動(dòng)壓力作用于其它車輪。這種效果使你可以在很短的時(shí)間內(nèi)停車時(shí)還能保持充分的轉(zhuǎn)向控制，即使一個(gè)或更多的車輪在冰面上時(shí)，這個(gè)系統(tǒng)用計(jì)算機(jī)控制車速，當(dāng)它檢測(cè)到一個(gè)或更多的車輪已經(jīng)停止或比余下的車輪轉(zhuǎn)向慢時(shí)，計(jì)算機(jī)就會(huì)發(fā)出信號(hào)立刻再次驅(qū)動(dòng)或減少車輪上的壓力來是它們繼續(xù)轉(zhuǎn)向。這種電磁的制動(dòng)在一秒中可以發(fā)生十次或更多次，比人手動(dòng)操作制動(dòng)快很多。如果你踩制動(dòng)很難實(shí)施防抱死系統(tǒng)，你就會(huì)感到強(qiáng)烈的振動(dòng)，這是正常情況并且表明系統(tǒng)正在運(yùn)轉(zhuǎn)。然爾，

85、對(duì)于對(duì)這個(gè)沒有期望的人，可能不關(guān)心這個(gè)。如果你的車有ABS，閱讀你的操作手冊(cè)，可以查找更多的相關(guān)信息。</p><p>　　這個(gè)系統(tǒng)包括電子控制單元，液壓傳動(dòng)機(jī)構(gòu)，和每個(gè)車輪上的車速傳感器。如果控制單元檢測(cè)到故障，它就會(huì)點(diǎn)亮ABS警示燈告之系統(tǒng)有問題。如果出現(xiàn)問題，防抱死就不會(huì)運(yùn)轉(zhuǎn)而制動(dòng)系統(tǒng)將正常運(yùn)轉(zhuǎn)。</p><p><b>　　3.摩擦材料</b></p&g

86、t;<p>　　制動(dòng)蹄片和襯墊以相似的方式構(gòu)成。襯墊或蹄片用金屬板材和摩擦襯料組成。襯料聯(lián)結(jié)（粘貼）或鉚接在金屬上。一般來說，鉚接襯料更具優(yōu)越性，但是高質(zhì)量的聯(lián)結(jié)（粘貼）材料同樣合適。</p><p>　　摩擦材料因規(guī)格，襯墊的類型，材料的復(fù)合情況而不同，通常分為：石棉，有機(jī)材料，非金屬，金屬。這些復(fù)合物的差異在于它們的類型，摩擦材料所用的百分比，材料黏合劑和調(diào)節(jié)劑的使用。</p>&

87、lt;p>　　一般來說，有機(jī)材料和非金屬石棉復(fù)合制動(dòng)器聲音較低，但這種制動(dòng)器必須在高溫下操縱，因此它們可能不是在運(yùn)輸重物或在山上駕駛的最好選擇。在大多數(shù)情況下，這些襯料比金屬?gòu)?fù)合襯墊運(yùn)轉(zhuǎn)快，因此通常情況下，還是用其它材料代替它們。但是，用這些材料時(shí)，車輪更耐用一些。</p><p>　　半金屬或金屬?gòu)?fù)合制動(dòng)襯料因復(fù)合的金屬不同而不同。一般來說，金屬的質(zhì)量越高，摩擦材料越耐熱。這一優(yōu)點(diǎn)使這種材料使用于運(yùn)輸重物

88、，但前提是要在襯墊到達(dá)操縱所需溫度前剎車。在寒冷的早晨，這樣材料的裝置不容易剎車。而且金屬和本金屬材料更容易發(fā)出尖聲。在大多數(shù)情況下，金屬?gòu)?fù)合襯墊比非金屬襯墊耐久性強(qiáng)，但是車輪的損耗較大。如果選用金屬襯墊，就要經(jīng)常更換車輪子。</p><p>　　在決定哪種類型的制動(dòng)襯料適合時(shí)，不妨考慮一下現(xiàn)代汽車的制動(dòng)材料是與車輛的性能相匹配的。改變國(guó)家統(tǒng)一規(guī)格的材料反而會(huì)影響制動(dòng)器的感覺或響應(yīng)。在改變制動(dòng)器材料之前，和零售商