外文翻譯---制動系統(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>　　制動系統(tǒng)</b></p><p>　　制動系統(tǒng)是汽車中最重要的系統(tǒng)。 如果制動系統(tǒng)失效，結果可能是損失慘重的。當你踩在制動器的踏板上，你希望把車輛停下來。制動器的踏板操縱著制動系統(tǒng)，其原因有二。首先，具有一定壓力的制動液通過制動管路被輸送到制動系統(tǒng)的制動主缸中，這不需占據(jù)很多空間或導致線路問題。其次，制動液提供踏板所需要的強機械壓力，但是大部分壓力作用在

42、車輪上。制動踏板和制動主缸里的主缸活塞相連，主缸里充滿了液壓制動液。主缸由一個活塞和一個貯液罐組成。</p><p>　　現(xiàn)代主缸實際上有兩個分離的氣缸。這樣的系統(tǒng)叫做雙環(huán)行。因為前面的汽缸和前閘相連，后部的氣缸和后閘相連（有些車輛采用對角線相連接的方法）這兩個氣缸是分離的，在緊急剎車情況下，這個系統(tǒng)的一部分將失去作用。</p><p>　　整個液壓系統(tǒng)從主缸到車輪充滿著液壓制動流體。當踩

43、下制動器踏板，主缸上的活塞便跟著運轉，這就向管路中的液體施加了很大的壓力。制動液被迫作用于氣缸活塞（鼓式制動器）或卡鉗活塞（盤式制動閘）從而施加壓力于制動蹄片和襯墊。制動蹄片和車輪之間或制動襯墊和制動盤之間的摩擦使車輛減速，最終使它停下來。</p><p>　　依附于制動器踏板上的是一個開關，當踩下踏板時，制動器的燈也隨之點亮。直到松開制動器踏板并且踏板回到原位置時，燈才熄滅。</p><p&

44、gt;　　在每一個鼓式制動系統(tǒng)的制動輪缸里，都有兩個活塞。其中一個在一邊的終端，這個活塞向外面的相反方向推動。在盤式制動系統(tǒng)中，制動輪缸是制動鉗的一部分（制動輪缸多則四個，少則兩個）無論盤式制動器還是鼓式制動器，所有活塞均采用某種類型的橡膠封口以防活塞周圍的泄漏。制動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>　　當松開制動器踏板，主缸的回味彈簧推動主缸活塞回到正常位置。主缸活塞里的單向閘

45、使液體流向制動輪缸或制動鉗，活塞向回運動。然后，隨著制動蹄片的返回，回位彈簧推動制動蹄片回到釋放狀態(tài)下的原始位置，通過補償氣孔，流體返回到主缸，補償孔一直打開，直至活塞返回到原始位置。系統(tǒng)中泄漏的流體將通過補償孔中的流體得到代替。</p><p>　　雙環(huán)形制動系統(tǒng)使用一個開關來點燈，以警示制動器失效。這個開關在主缸附近的一個閘門里。閘門里的活塞受力，作用一邊前后的制動環(huán)路。當壓力平衡時，活塞保持靜止，但是當一個

46、環(huán)路中出現(xiàn)泄漏時，制動器作用過程中的強大壓力迫使活塞從一邊到另一邊，同時開關關閉，警示燈亮起。在發(fā)動機啟動或制動器停止的過程中，通過點火裝置的開火也可使燈點亮。</p><p>　　前輪用盤式，后面用鼓式制動系統(tǒng)也有一個計量器閥門防止前面的盤閘門和后面的閘門連接到鼓形裝置之前運作。這也確保了前閘不會單獨用于停止車輛。一個比例恰當?shù)拈l門通常用來為后面的制動系統(tǒng)減壓，以防止在艱難的剎車狀態(tài)下后面的輪子不聽使喚。<

47、;/p><p><b>　　摩擦材料</b></p><p>　　制動蹄片和襯墊以相似的方式構成。襯墊或蹄片用金屬板材和摩擦襯料組成。襯料聯(lián)結（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（粘貼）材料同樣合適。</p><p>　　摩擦材料因規(guī)格，襯墊的類型，材料的復合情況而不同，通常分為：石棉，有機材料，非金屬，金屬。這些

48、復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><p>　　一般來說，有機材料和非金屬石棉復合制動器聲音較低，但這種制動器必須在高溫下操縱，因此它們可能不是在運輸重物或在山上駕駛的最好選擇。在大多數(shù)情況下，這些襯料比金屬復合襯墊運轉快，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，車輪更耐用一些。</p><p>　　半金屬或金屬復合制動

49、襯料因復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)點使這種材料使用于運輸重物，但前提是要在襯墊到達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，金屬復合襯墊比非金屬襯墊耐久性強，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襯料適合時，不妨考慮一下現(xiàn)代汽車的制動材料是與

50、車輛的性能相匹配的。改變國家統(tǒng)一規(guī)格的材料反而會影響制動器的感覺或響應。在改變制動器材料之前，和零售商或部分供貨商談談，請他們幫忙決定哪種襯料更合適。謹記有一些情況，比如拖拉，緊急剎車和快速起步，在坡道上行駛，以及賽事需要高質(zhì)量的材料。在制動系統(tǒng)中還需要一些額外的材料，比如合成纖維和復合碳。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，取決于所購買的產(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.制動液</b></p><p>　　制動液是一種具有特殊性能的油。它被設計成在低溫下不會凝固而在高溫下不會沸騰。（如果制動液沸騰，需要有一個柔軟的制動踏板并使車很難停下來）。制動液系統(tǒng)。</p><p>　　制動液的裝置位于主缸的頂部。目前大多數(shù)的車都有一個容易看見的裝制動液的裝置，為的是不用打開蓋子就可以看得見制動

52、液的油面。隨著制動踏板的運動制動液就會緩慢的下降，正常情況下是這樣的。如果制動液在很短的時間內(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系統(tǒng)了。保持制動液裝置充滿制動液除非你需要維修它，制動液必須保持很高的沸點。位于在空氣中的制動液就會吸收空氣中的潮氣引起制動液低于沸點。</p><p>　　制動液通過一系列的管路從主缸到達各車輪。橡膠軟管只用在需要彈力的地方，比如應用在前輪。在車的行進中上下來回運

53、動。系統(tǒng)的其它部分在所有的連接點上都應用了無腐蝕性的無縫鋼管。如果鋼線需要修理的話，最好的方法就是代替這條線。如果這不符合實際，那么為了制動系統(tǒng)可以用特殊的裝置修理它。你不可以用銅管來修理制動系。它們是危險也是不正確的。</p><p>　　在盤式制動器中，主缸中的液體被迫壓縮到活塞中?；钊魍鶑瓦\動，擠壓這兩個制動塊和連接著車輪的制動蹄。這個過程類似于自行車的剎車，自行車的兩個橡膠板作用在車輪上制造摩擦。<