外文翻譯-手動(dòng)變速器

1、附錄A.Manual Tran smissi onIt s no secret that cars with manual transmissions are usually more fun to drive than the automatic-equipped counterparts. If you have even a passing interest in the act of driv ing, the n cha nces are you also appreciate a fin e-shift ing manual gearbox. But how does a manu

2、al tran smissi on actually work?A history hows that manual tran smissi ons preceded automatics by several decades. In fact, up until General Motors offered an automatic in 1938, all cars were of the shift-it-yourself variety. While it s logical for many types of today s vehicles to be eqiwith an aut

3、omaticsuch as afiZle seda n, SUV or pickupthe fact remai ns thatnothing is more of a thrill to drive than a tautly suspendedsport sedan, snort coupe or two-sealer equipped with a precise-shift ing five-or six-speed gearboxWe know whicn types or cars have manual trannies. Now let s takeaatobow they w

4、ork. From the most basic four-speed manual in a car from the 60s)the most high-tech six-speed one in a car of today, the principles of a manual gearbox are the same. The driver must shift from gear to gear. Normally, a manual tran smissi on bolts to a clutch housing (or bell housing) , in turn, bolt

5、s to the back of the engine. If the vehicle has front-wheel drive, the transmission still attaches to the engine in a similar fashion but is usually referred to as a transaxle. This is because the transmission, differential and drive axles are one complete unit. In a front-wheel-drive car, the trans

6、mission also serves as part of the front axle for the front wheels. In the remaining text, a transmission and a transaxle will both be referred to using the term transmission.The function of any transmission is transferring engine power to the driveshaft and rear wheels (or axle halfshafts and front

7、 wheels in a front-wheel-drive vehicle). Gears in side the tran smissi on cha nge the vehicle drive-wheel speed and torque in relati on to engine speed and torque Lower(numerically higher) gear ratios serve as torque multipliers and help the engine to develop eno ugh power to accelerate from a sta n

8、dstill.Initially, power and torque from the engine comes into the front of the transmissions and rotates the main drive gear (or in put shaft), which meshes with the cluster or coun tershaft geara series of gears forged in to one piece that resembles a cluster of gears. Thecluster-gear assembly rota

9、tes any time the clutch is en gaged to a running en gin,e whether or not the tran smissi on is in gear or in n eutral.There are two basic types of manual tran smissi ons. The slid in g-gear type and the constantmesh design. With the basic and now obsoleteasliylpeg nothingis tur ning in side the tran

10、 smissi on case except the main drive gear and cluster gear whe n the trans is in neutral. In order to mesh the gears and apply engine power to move the vehicle, the driver presses the clutch pedal and moves the shifter han dle, which in tur n moves the shift lin kage and forks to slide a gear along

11、 the main shaft, which is moun ted directly above the cluster. Once the gears are meshed, the clutch pedal is released and the engine is sent to the drive wheels. There can be several gears on the main shaft of differe nt diameters and tooth coun ts, and the tran smissi on shift lin kage is desig ne

12、d so the driver has to unm esh one gear before being able to mesh ano ther. With these older tran smissi ons, gear clash is a problem because the gears are all rotat ing at differe nt speeds.All moder n tran smissi ons are of the con sta nt-mesh type, which still uses a similar gear arran geme nt as

13、 the slidi ng-gear type. Howeverall the main shaft gears are in con sta nt mesh with the cluster gears. This is possible becausethe gears on the main shaft are not splined to the shaft, but are free to rotate on it. With a constant-mesh gearbox, the main drive gear, cluster gear and all the main sha

14、ft gears are always turning, eve n whe n the tran smissi on is in n eutral.Alon gside each gear on the main shaft is a dog clutch, with a hub that positively splined to the shaft and an outer ring that can slide over against each gear. Both the main shaft gear and the ring of the dog clutch have a r

15、ow of teeth. Moving shift lin kage moves the dog clutch aga inst the adjace nt main shaft gear, caus ing the teeth to in terlock and solidly lock the gear to the main shaft.To preve nt gears from grinding or clash ing duri ng en gageme nt, a con sta nt-mesh, fully synchronized manual transmission is

16、 equipped with synchronizers. A synchronizer typically consists of an inner-splined hub, an outer sleeve, shifter plates, lock rings (or spri ngs) and block ing rin gs. The hub is spli ned onto the main shaft betwee n a pair of main drive gears. Held in place by the lock rings, the shifter plates po

17、sition the sleeve over the hub while also hold ing the floati ng block ing rings in proper alig nment.A synchro s inner hub and sleeve are made of steel, but the blocking ringof the syn chro that rubs on the gear to cha nge its speedisusually made of a softermaterial, such as brass. The block ing ri

18、ng has teeth that match the teeth on the dog clutch. Most syn chros perform double dutythey push the syn chro ione directi on and lockone gear to the main shaft. Push the syn chro the other way and it dise ngages from the first gear, passes through a neutral position, and engages a gear on the other

19、 side.That s the basics on the inn ework ings of a manual tran smissi on. As for adva nces, they have bee n exte nsive over the years, mainly in the area of additi onal gears. Back in the 60 spur-speeds were com mon in America n and Europea n performa nee cars. Most of these transmissions had 1:1 fi

20、nal-drive ratios with no overdrives. Today, overdriven five-speeds are sta ndard on practically all passe nger cars available with a manual gearbox.Overdrive is an arran geme nt of geari ng that provides more revoluti ons of the drive n shaft (the driveshaft going to the wheels than the driving shaf

21、t(crankshaft of the engine . For example, a transmission with a fourth-gear ratio of 1:1 and a fifth-gear ratio of 0.70:1 will reduce engine rpm by 30 percent, while the vehicle maintains the same road speed. Thus, fuel efficiency will improve and engine wear will be notably reduced. Today, six-spee

22、d tran smissi ons are beco ming more and more com mon. One of the first cars sold in America with a six- speed was the 89 Corvetfesigned by Chevrolet and Zahnradfabrik Friedrichshafen (ZF) and built by ZF in Germany, this tough-as-nails six-speed was available in the Corvette up to the conclusion of

23、 the 96 model(yearette)dayuses a Tremec T56 six-speed moun ted at the back of the car.Many cars are available today with six-speeds, in clud ing the Mazda Miata, Porsche Boxster S and 911, Dodge Viper, Mercedes-Be nz SLK320, Ho nda S2000, Toyota Celica GT-S and many others. Some of these gearboxes p

24、rovide radical 50-percent (0.50:1) sixth-gear overdrives such as in the Viper and Corvette, while others provide tightly spaced gear ratios like in the S2000 and Celica for spirited backroad performance driving. While the bigger cars mentioned above such as the Viper and Vette often have two overdri

25、ve ratios (fifth and sixth) the smaller cars like the Celica and S2000 usually have one overdriven gear ratio (sixth) and fifth is 1:1.Clearly a slick-shifti ng manual tran smissi on is one of the mai n comp onents in a fun-to-drive car, along with a powerful engine, con fide nce-i nspiri ng suspe n

26、sion and compete nt brakes.附錄B.手動(dòng)變速器相對(duì)于自動(dòng)變速箱的車(chē)手動(dòng)變速箱汽車(chē)開(kāi)起來(lái)有更好的駕駛樂(lè)趣這是眾所周知 的。哪怕你對(duì)駕駛僅有一點(diǎn)興趣，那么你也會(huì)對(duì)一個(gè)齒輪變速器的完美工作刮目相看。 那么手動(dòng)變速器到底是怎么工作的呢？手動(dòng)變速器在幾十年以前就被自動(dòng)變速箱所取代了， 事實(shí)上從前的車(chē)都是配備的 手動(dòng)變速箱，直到1938年通用汽車(chē)公司推出第一款自動(dòng)變速車(chē)。今天的諸多車(chē)輛像 轎車(chē)、越野車(chē)、小型載貨汽車(chē)采用自動(dòng)變速是很符合邏輯的，因?yàn)闆](méi)有任何事會(huì)比駕 駛一個(gè)配有5-6個(gè)檔的手動(dòng)變速箱的車(chē)更令人緊張不安了?，F(xiàn)在讓我們看看他們是怎么工作的。從 60年代的四速手動(dòng)到今天的最

27、高六速變 速器的基本原理是沒(méi)有改變的。駕駛員仍然要操縱齒輪使其相互嚙合。通常，變速器 與離合器殼連接，離合器的另一面再同發(fā)動(dòng)機(jī)相連。如果是前輪驅(qū)動(dòng)的車(chē)仍然是這種 簡(jiǎn)單的連接方式，但要稱(chēng)其為驅(qū)動(dòng)橋，這是因?yàn)樽兯傧浜万?qū)動(dòng)軸是一個(gè)整體的機(jī)構(gòu)。 在前驅(qū)車(chē)上變速箱也是前輪驅(qū)動(dòng)橋的一部分。 在過(guò)去的概念中變速器跟驅(qū)動(dòng)橋被統(tǒng)稱(chēng) 為變速驅(qū)動(dòng)橋。變速箱的功能就是將發(fā)動(dòng)機(jī)的動(dòng)力傳遞給驅(qū)動(dòng)軸和后輪（前驅(qū)車(chē)是傳遞給半軸和 前輪）通過(guò)變速箱中的齒輪改變了發(fā)動(dòng)機(jī)傳給車(chē)輪的速度和扭矩。 低傳動(dòng)比能夠增大 扭矩使發(fā)動(dòng)機(jī)有足夠的加速能量。起初，發(fā)動(dòng)機(jī)將動(dòng)力和扭力傳給變速箱的輸入軸，輸入軸上的齒輪與中間軸上的 齒輪嚙合，從而形成

28、一個(gè)齒輪組。這個(gè)齒輪組的任何一次轉(zhuǎn)動(dòng)都是離合器與運(yùn)轉(zhuǎn)的發(fā) 動(dòng)機(jī)相連的結(jié)果，總之變速器就是一個(gè)齒輪的組合體。有兩種手動(dòng)變速器。滑動(dòng)型的和常嚙合型的?；瑒?dòng)型的（已經(jīng)不用）變速器處于 空檔時(shí)，除了主動(dòng)齒輪和齒輪組轉(zhuǎn)動(dòng)其他都是不轉(zhuǎn)的。 為了使齒輪嚙合從而讓發(fā)動(dòng)機(jī) 輸出的動(dòng)力帶動(dòng)汽車(chē)運(yùn)動(dòng)駕駛員要踏下離合器踏板同時(shí)操作換檔桿。換檔桿會(huì)聯(lián)動(dòng)換檔撥叉帶動(dòng)安裝在輸入軸上的相應(yīng)齒輪沿輸入軸移動(dòng)。一旦齒輪嚙合，釋放離合器踏板后發(fā)動(dòng)機(jī)動(dòng)力就會(huì)傳給驅(qū)動(dòng)輪。輸入軸上會(huì)有多個(gè)不同直徑不同齒數(shù)的齒輪。因?yàn)?換檔是聯(lián)動(dòng)的所以駕駛員必須使已經(jīng)嚙合的齒輪分離才能使另一對(duì)齒輪嚙合。由于齒輪嚙合時(shí)的速度不同，老式變速箱會(huì)有換檔沖擊的問(wèn)題?，F(xiàn)代的變速箱都是常嚙合型的，齒輪布置是沿用滑動(dòng)型的布置方式。然而所有主 軸上的齒輪與中間軸上齒輪都是常嚙合的， 這是因?yàn)橹鬏S上的齒輪在軸上是可以來(lái)回 移動(dòng)的而不是用花鍵鏈連接的。 即使變速箱處于空檔狀態(tài)，常嚙合型變速箱上的各個(gè) 齒輪都是在轉(zhuǎn)動(dòng)的。主軸上每個(gè)齒輪旁邊都有一個(gè)爪式離合器（接合套），花鍵轂用內(nèi)花鍵連接在主 軸上的花鍵上。主軸上的齒輪和接合套的外環(huán)都有花鍵。 當(dāng)操縱換檔桿時(shí)就會(huì)使接合 套對(duì)著主軸齒輪移動(dòng)，最終使接合套與齒輪互鎖從而使齒輪嚙合隨主軸轉(zhuǎn)動(dòng)。為了避免齒輪換檔同步前嚙合時(shí)產(chǎn)生的接合齒間沖擊，手動(dòng)變速