外文翻譯---制動(dòng)系統(tǒng)

1、<p><b>　　附 錄1</b></p><p>　　Hydraulic Brake Systems</p><p>　　The braking system is the most important system in cars. If the brake system fail, the result can be disastrous.</

2、p><p>　　When you step on the brake pedal, you expect the vehicle to stop. The brake pedal operates a hydraulic system that is used for two reasons. First, fluid under pressure can be carried to all parts of the

3、 vehicle by small hoses or metal lines with out taking up a lot of room or causing routing problems. Second, the hydraulic fluid offers a great mechanical advantage-little foot pressure is required on the pedal, but a gr

4、eat deal of pressure is generated at the wheels. The brake pedal is linked to </p><p>　　Modern master cylinders are actually two separate cylinders. Such a system is called a dual circuit, because the front

5、cylinder is connected to the front brakes and the rear cylinder to the rear brakes. (Some vehicles are connected diagonally.) The two cylinders are actually separated, allowing for emergency stopping power should one pa

6、rt of the system fail.</p><p>　　The entire hydraulic system from the master cylinder to the wheels is full of hydraulic brake fluid. When the brake pedal is depressed, the pistons in the master cylinder are

7、forced to move, exerting tremendous force on the fluid in the lines. The fluid has nowhere to go, and forces the wheel cylinder pistons (drum brakes) or caliper pistons (disc brakes) to exert pressure on the brake shoes

8、or pads. The friction between the brake shoe and wheel drum or the brake pad and rotor (disc) slows the v</p><p>　　Also attached to the brake pedal is a switch that lights the brake lights as the pedal is de

9、pressed. The lights stay on until the brake pedal is released and returns to its normal position.</p><p>　　Each wheel cylinder in a drum brake system contains two pistons, one at either end, which push outwa

10、rd in opposite directions. In disc brake systems, the wheel cylinders are part of the caliper (there can be as many as four or as few as one). Whether disc or drum type, all pistons use some type of rubber seal to preven

11、t leakage around the piston, and a rubber dust boot seals the outer ends of the wheel cylinders against dirt and moisture.</p><p>　　When the brake pedal is released, a spring pushes the master cylinder pisto

12、ns back to their normal positions. Check valves in the master cylinder piston allow fluid to flow toward the wheel cylinders or calipers as the piston returns. Then as the brake shoe return springs pull the brake shoes b

13、ack to the released position, excess fluid returns to the master cylinder through compensating ports, which have been uncovered as the pistons move back. Any fluid that has leaked from the system will also</p><

14、;p>　　All dual circuit brake systems use a switch to activate a light, warning of brake failure. The switch is located in a valve mounted near the master cylinder. A piston in the valve receives pressure on each end fr

15、om the front and rear brake circuits. When the pressures are balanced, the piston remains stationary, but when one circuit has a leak, greater pressure during the application of the brakes will force the piston to one si

16、de or the other, closing the switch and activating the warning light</p><p>　　Front disc, rear drum brake systems also have a metering valve to prevent the front disc brakes from engaging before the rear bra

17、kes have contacted the drums. This ensures that the front brakes will not normally be used alone to stop the vehicle. A proportioning valve is also used to limit pressure to the rear brakes to prevent rear wheel lock-up

18、during hard braking.</p><p>　　1. 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.

19、 The lining is either bonded (glued) to the metal, or riveted. Generally, riveted linings provide superior performance, but good quality bonded linings are perfectly adequate.</p><p>　　Friction materials wil

20、l vary between manufacturers and 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 fricti

21、on materials used, material binders 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 a

22、t the expense of high temperature 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 usu

23、ally replace them more often. 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

24、compound. Again, generally speaking, 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 perform

25、ance before the pad reaches operating 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 br

26、ake lining is right for you, keep 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 adverse

27、ly affect brake feel or responsiveness. 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 a

28、s towing, stop and go driving, 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 perf

29、ormance for towing, mountain driving 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

30、linings, while many of the street applications are more like the non-metallic.</p><p>　　2. Brake fluid</p><p>　　On a disk brake, the fluid from the master cylinder is forced into a caliper where

31、 it presses against a piston. The piston, in-turn, squeezes two brake pads against the disk(rotor)which is attached to the wheel, forcing it to slow down or stop. This process is similar to a bicycle brake where two rubb

32、er pads rub against the wheel rim creating friction.</p><p>　　With drum brakes, fluid is forced into the wheel cylinder which pushes the brake shoes out so that the friction linings are pressed against the d

33、rum which is attached to the wheel, causing the wheel to stop.</p><p>　　In either case, the friction surfaces of the pads on a disk brake system, or the shoes on a drum brake convert the forward motion of th

34、e vehicle into heat. Heat is what causes the friction surfaces (linings) of the pads and shoes to eventually wear out and require replacement.</p><p>　　Brake fluid is a special oil that has specific properti

35、es. It is designed to withstand cold temperatures without thickening as well as very high temperatures without boiling.(If the brake fluid should boil, it will cause you to have a spongy pedal and the car will be hard to

36、 stop). Figure shows a brake hydraulic system.</p><p>　　The brake fluid reservoir is on top of the master cylinder. Most cars today have a transparent r reservoir so that you can see the level without openin

37、g the cover. The brake fluid level will drop slightly as the brake pads wear. This is a normal condition and no cause for concern. If the level drops noticeably over a short period of time or goes down to about two third

38、s full, have your brakes checked as soon as possible. Keep the reservoir covered except for the amount of time you need to fill i</p><p>　　The brake fluid travels from the master cylinder to the wheels throu

39、gh a series of steel tubes and reinforced rubber hoses. Rubber hoses are only used in places that require flexibility, such as at the front wheels, which move up and down as well as steer. The rest of the system uses non

40、-corrosive seamless steel tubing with special fittings at all attachment points. If a steel line requires a repair, the best procedure is to replace the compete line. If this is not practical, a line can be repai</p&g

41、t;<p><b>　　制動(dòng)系統(tǒng)</b></p><p>　　制動(dòng)系統(tǒng)是汽車(chē)中最重要的系統(tǒng)。 如果制動(dòng)系統(tǒng)失效，結(jié)果可能是損失慘重的。當(dāng)你踩在制動(dòng)器的踏板上，你希望把車(chē)輛停下來(lái)。制動(dòng)器的踏板操縱著制動(dòng)系統(tǒng)，其原因有二。首先，具有一定壓力的制動(dòng)液通過(guò)制動(dòng)管路被輸送到制動(dòng)系統(tǒng)的制動(dòng)主缸中，這不需占據(jù)很多空間或?qū)е戮€路問(wèn)題。其次，制動(dòng)液提供踏板所需要的強(qiáng)機(jī)械壓力，但是大部分壓力作用在

42、車(chē)輪上。制動(dòng)踏板和制動(dòng)主缸里的主缸活塞相連，主缸里充滿了液壓制動(dòng)液。主缸由一個(gè)活塞和一個(gè)貯液罐組成。</p><p>　　現(xiàn)代主缸實(shí)際上有兩個(gè)分離的氣缸。這樣的系統(tǒng)叫做雙環(huán)行。因?yàn)榍懊娴钠缀颓伴l相連，后部的氣缸和后閘相連（有些車(chē)輛采用對(duì)角線相連接的方法）這兩個(gè)氣缸是分離的，在緊急剎車(chē)情況下，這個(gè)系統(tǒng)的一部分將失去作用。</p><p>　　整個(gè)液壓系統(tǒng)從主缸到車(chē)輪充滿著液壓制動(dòng)流體。當(dāng)踩

43、下制動(dòng)器踏板，主缸上的活塞便跟著運(yùn)轉(zhuǎn)，這就向管路中的液體施加了很大的壓力。制動(dòng)液被迫作用于氣缸活塞（鼓式制動(dòng)器）或卡鉗活塞（盤(pán)式制動(dòng)閘）從而施加壓力于制動(dòng)蹄片和襯墊。制動(dòng)蹄片和車(chē)輪之間或制動(dòng)襯墊和制動(dòng)盤(pán)之間的摩擦使車(chē)輛減速，最終使它停下來(lái)。</p><p>　　依附于制動(dòng)器踏板上的是一個(gè)開(kāi)關(guān)，當(dāng)踩下踏板時(shí)，制動(dòng)器的燈也隨之點(diǎn)亮。直到松開(kāi)制動(dòng)器踏板并且踏板回到原位置時(shí)，燈才熄滅。</p><p&

44、gt;　　在每一個(gè)鼓式制動(dòng)系統(tǒng)的制動(dòng)輪缸里，都有兩個(gè)活塞。其中一個(gè)在一邊的終端，這個(gè)活塞向外面的相反方向推動(dòng)。在盤(pán)式制動(dòng)系統(tǒng)中，制動(dòng)輪缸是制動(dòng)鉗的一部分（制動(dòng)輪缸多則四個(gè)，少則兩個(gè)）無(wú)論盤(pán)式制動(dòng)器還是鼓式制動(dòng)器，所有活塞均采用某種類(lèi)型的橡膠封口以防活塞周?chē)男孤?。制?dòng)輪缸的外終端加之橡膠防塵封口，用以防止臟物和潮濕。</p><p>　　當(dāng)松開(kāi)制動(dòng)器踏板，主缸的回味彈簧推動(dòng)主缸活塞回到正常位置。主缸活塞里的單向閘

45、使液體流向制動(dòng)輪缸或制動(dòng)鉗，活塞向回運(yùn)動(dòng)。然后，隨著制動(dòng)蹄片的返回，回位彈簧推動(dòng)制動(dòng)蹄片回到釋放狀態(tài)下的原始位置，通過(guò)補(bǔ)償氣孔，流體返回到主缸，補(bǔ)償孔一直打開(kāi)，直至活塞返回到原始位置。系統(tǒng)中泄漏的流體將通過(guò)補(bǔ)償孔中的流體得到代替。</p><p>　　雙環(huán)形制動(dòng)系統(tǒng)使用一個(gè)開(kāi)關(guān)來(lái)點(diǎn)燈，以警示制動(dòng)器失效。這個(gè)開(kāi)關(guān)在主缸附近的一個(gè)閘門(mén)里。閘門(mén)里的活塞受力，作用一邊前后的制動(dòng)環(huán)路。當(dāng)壓力平衡時(shí)，活塞保持靜止，但是當(dāng)一個(gè)

46、環(huán)路中出現(xiàn)泄漏時(shí)，制動(dòng)器作用過(guò)程中的強(qiáng)大壓力迫使活塞從一邊到另一邊，同時(shí)開(kāi)關(guān)關(guān)閉，警示燈亮起。在發(fā)動(dòng)機(jī)啟動(dòng)或制動(dòng)器停止的過(guò)程中，通過(guò)點(diǎn)火裝置的開(kāi)火也可使燈點(diǎn)亮。</p><p>　　前輪用盤(pán)式，后面用鼓式制動(dòng)系統(tǒng)也有一個(gè)計(jì)量器閥門(mén)防止前面的盤(pán)閘門(mén)和后面的閘門(mén)連接到鼓形裝置之前運(yùn)作。這也確保了前閘不會(huì)單獨(dú)用于停止車(chē)輛。一個(gè)比例恰當(dāng)?shù)拈l門(mén)通常用來(lái)為后面的制動(dòng)系統(tǒng)減壓，以防止在艱難的剎車(chē)狀態(tài)下后面的輪子不聽(tīng)使喚。<

47、;/p><p><b>　　摩擦材料</b></p><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(lái)說(shuō)，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(lèi)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

48、復(fù)合物的差異在于它們的類(lèi)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><p>　　一般來(lái)說(shuō)，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(chē)輪更耐用一些。</p><p>　　半金屬或金屬?gòu)?fù)合制動(dòng)

49、襯料因復(fù)合的金屬不同而不同。一般來(lái)說(shuō)，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，但前提是要在襯墊到達(dá)操縱所需溫度前剎車(chē)。在寒冷的早晨，這樣材料的裝置不容易剎車(chē)。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(chē)輪的損耗較大。如果選用金屬襯墊，就要經(jīng)常更換車(chē)輪子。</p><p>　　在決定哪種類(lèi)型的制動(dòng)襯料適合時(shí)，不妨考慮一下現(xiàn)代汽車(chē)的制動(dòng)材料是與

50、車(chē)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(jué)或響應(yīng)。在改變制動(dòng)器材料之前，和零售商或部分供貨商談?wù)劊?qǐng)他們幫忙決定哪種襯料更合適。謹(jǐn)記有一些情況，比如拖拉，緊急剎車(chē)和快速起步，在坡道上行駛，以及賽事需要高質(zhì)量的材料。在制動(dòng)系統(tǒng)中還需要一些額外的材料，比如合成纖維和復(fù)合碳。這些材料性能好，使用于拖拉，山路行駛或比賽。磨損性能和金屬或非金屬襯料相似，取決于所購(gòu)買(mǎi)的產(chǎn)品。很多賽事要求金屬材料，街上行駛需要非金屬材料。<

51、;/p><p><b>　　2.制動(dòng)液</b></p><p>　　制動(dòng)液是一種具有特殊性能的油。它被設(shè)計(jì)成在低溫下不會(huì)凝固而在高溫下不會(huì)沸騰。（如果制動(dòng)液沸騰，需要有一個(gè)柔軟的制動(dòng)踏板并使車(chē)很難停下來(lái)）。制動(dòng)液系統(tǒng)。</p><p>　　制動(dòng)液的裝置位于主缸的頂部。目前大多數(shù)的車(chē)都有一個(gè)容易看見(jiàn)的裝制動(dòng)液的裝置，為的是不用打開(kāi)蓋子就可以看得見(jiàn)制動(dòng)

52、液的油面。隨著制動(dòng)踏板的運(yùn)動(dòng)制動(dòng)液就會(huì)緩慢的下降，正常情況下是這樣的。如果制動(dòng)液在很短的時(shí)間內(nèi)下降得明顯或者下降了三分之二，那么就要盡快的檢查你的制動(dòng)系統(tǒng)了。保持制動(dòng)液裝置充滿制動(dòng)液除非你需要維修它，制動(dòng)液必須保持很高的沸點(diǎn)。位于在空氣中的制動(dòng)液就會(huì)吸收空氣中的潮氣引起制動(dòng)液低于沸點(diǎn)。</p><p>　　制動(dòng)液通過(guò)一系列的管路從主缸到達(dá)各車(chē)輪。橡膠軟管只用在需要彈力的地方，比如應(yīng)用在前輪。在車(chē)的行進(jìn)中上下來(lái)回運(yùn)

53、動(dòng)。系統(tǒng)的其它部分在所有的連接點(diǎn)上都應(yīng)用了無(wú)腐蝕性的無(wú)縫鋼管。如果鋼線需要修理的話，最好的方法就是代替這條線。如果這不符合實(shí)際，那么為了制動(dòng)系統(tǒng)可以用特殊的裝置修理它。你不可以用銅管來(lái)修理制動(dòng)系。它們是危險(xiǎn)也是不正確的。</p><p>　　在盤(pán)式制動(dòng)器中，主缸中的液體被迫壓縮到活塞中?；钊魍鶑?fù)運(yùn)動(dòng)，擠壓這兩個(gè)制動(dòng)塊和連接著車(chē)輪的制動(dòng)蹄。這個(gè)過(guò)程類(lèi)似于自行車(chē)的剎車(chē)，自行車(chē)的兩個(gè)橡膠板作用在車(chē)輪上制造摩擦。<