車輛工程外文翻譯----自動變速器如何工作

1、<p>　　附錄二 專業(yè)外文及翻譯</p><p>　　How Automatic Transmissions Work</p><p>　　If you have ever driven a car with an automatic transmission, then you know that there are two big differences between

2、an automatic transmission and a manual transmission: </p><p>　　There is no clutch pedal in an automatic transmission car. </p><p>　　There is no gear shift in an automatic transmission car. Once

3、you put the transmission into drive, everything else is automatic. </p><p>　　Both the automatic transmission (plus its torque converter) and a manual transmission (with its clutch) accomplish exactly the sam

4、e thing, but they do it in totally different ways. It turns out that the way an automatic transmission does it is absolutely amazing!</p><p>　　Planetary Gearsets & Gear Ratios</p><p>　　When

5、you take apart and look inside an automatic transmission, you find a huge assortment of parts in a fairly small space. Among other things, you see: </p><p>　　An ingenious planetary gearset </p><p&

6、gt;　　A set of bands to lock parts of a gearset </p><p>　　A set of three wet-plate clutches to lock other parts of the gearset </p><p>　　An incredibly odd hydraulic system that controls the clutc

7、hes and bands </p><p>　　A large gear pump to move transmission fluid around </p><p>　　The center of attention is the planetary gearset. About the size of a cantaloupe, this one part creates all

8、of the different gear ratios that the transmission can produce. Everything else in the transmission is there to help the planetary gearset do its thing. This amazing piece of gearing has appeared on HowStuffWorks before.

9、 You may recognize it from the electric screwdriver article. An automatic transmission contains two complete planetary gearsets folded together into one component. See How </p><p>　　Any planetary gearset has

10、 three main components: </p><p>　　The sun gear </p><p>　　The planet gears and the planet gears' carrier </p><p>　　The ring gear </p><p>　　Each of these three compon

11、ents can be the input, the output or can be held stationary. Choosing which piece plays which role determines the gear ratio for the gearset. Let's take a look at a single planetary gearset. </p><p>　　On

12、e of the planetary gearsets from our transmission has a ring gear with 72 teeth and a sun gear with 30 teeth. We can get lots of different gear ratios out of this gearset. </p><p>　　Also, locking any two of

13、the three components together will lock up the whole device at a 1:1 gear reduction. Notice that the first gear ratio listed above is a reduction -- the output speed is slower than the input speed. The second is an overd

14、rive -- the output speed is faster than the input speed. The last is a reduction again, but the output direction is reversed. There are several other ratios that can be gotten out of this planetary gear set, but these ar

15、e the ones that are relevant to our</p><p>　　This automatic transmission uses a set of gears, called a compound planetary gearset, that looks like a single planetary gearset but actually behaves like two pla

16、netary gearsets combined. It has one ring gear that is always the output of the transmission, but it has two sun gears and two sets of planets.</p><p>　　Next you can see the inside of the planet carrier. The

17、 shorter gears are engaged only by the smaller sun gear. The longer planets are engaged by the bigger sun gear and by the smaller planets. </p><p>　　First Gear In first gear, the smaller sun gear is driven

18、clockwise by the turbine in the torque converter. The planet carrier tries to spin counterclockwise, but is held still by the one-way clutch (which only allows rotation in the clockwise direction) and the ring gear turns

19、 the output. The small gear has 30 teeth and the ring gear has 72, so the gear ratio is: </p><p>　　Ratio = -R/S = - 72/30 = -2.4:1</p><p>　　So the rotation is negative 2.4:1, which means that th

20、e output direction would be opposite the input direction. But the output direction is really the same as the input direction -- this is where the trick with the two sets of planets comes in. The first set of planets enga

21、ges the second set, and the second set turns the ring gear; this combination reverses the direction. You can see that this would also cause the bigger sun gear to spin; but because that clutch is released, the bigger sun

22、 gear </p><p>　　Second Gear This transmission does something really neat in order to get the ratio needed for second gear. It acts like two planetary gearsets connected to each other with a common planet.&l

23、t;/p><p>　　The first stage of the planet carrier actually uses the larger sun gear as the ring gear. So the first stage consists of the sun (the smaller sun gear), the planet carrier, and the ring (the larger s

24、un gear). </p><p>　　The input is the small sun gear; the ring gear (large sun gear) is held stationary by the band, and the output is the planet carrier. For this stage, with the sun as input, planet carrier

25、 as output, and the ring gear fixed, the formula is: </p><p>　　1 + R/S = 1 + 36/30 = 2.2:1</p><p>　　The planet carrier turns 2.2 times for each rotation of the small sun gear. At the second stag

26、e, the planet carrier acts as the input for the second planetary gear set, the larger sun gear (which is held stationary) acts as the sun, and the ring gear acts as the output, so the gear ratio is: </p><p>

27、　　1 / (1 + S/R) = 1 / (1 + 36/72) = 0.67:1</p><p>　　To get the overall reduction for second gear, we multiply the first stage by the second, 2.2 x 0.67, to get a 1.47:1 reduction. This may sound wacky, but i

28、t works. </p><p>　　Third GearMost automatic transmissions have a 1:1 ratio in third gear. You'll remember from the previous section that all we have to do to get a 1:1 output is lock together any two of

29、 the three parts of the planetary gear. With the arrangement in this gearset it is even easier -- all we have to do is engage the clutches that lock each of the sun gears .</p><p>　　If both sun gears turn in

30、 the same direction, the planet gears lockup because they can only spin in opposite directions. This locks the ring gear to the planets and causes everything to spin as a unit, producing a 1:1 ratio. </p><p>

31、;<b>　　譯文：</b></p><p><b>　　自動變速器如何工作</b></p><p>　　如果您曾經駕駛一輛自動變速器汽車，那么你就知道，在自動變速器和手動變速器之間有兩個最大的區(qū)別： ?在自動變速器的汽車上沒有離合器踏板。 ?在自動變速器的汽車上沒有換檔。一旦調到前進檔上，一切都是自動的了。 無論是自動變速箱（制動帶扭矩轉

32、換器）和手動變速箱（制動帶離合器） 在原理上是一樣的，但他們在實現(xiàn)方法上完全不同。結果表明，自動變速器是絕對驚人！</p><p>　　行星齒輪裝置＆齒輪傳動比 </p><p>　　將我們拆開自動變速器進行觀察時，你會發(fā)現(xiàn)一個巨大組合的零件在一個相當小的空間。除其他事項外，你會看到： ?一個巧妙的行星齒輪組 ?一套制動帶，以鎖定部分齒輪部件</p><

33、;p>　　?一套三濕式離合器片，以鎖定其他部分齒輪裝置</p><p>　　?一個令人難以置信的奇數(shù)液壓系統(tǒng)，用來控制離合器和制動帶?一個大型齒輪泵，提供液體循環(huán)</p><p>　　關注的焦點是該行星齒輪裝置。大小約一個香瓜，這其中的一部分，創(chuàng)造了各個不同的齒輪傳動比。一切都在配合行星齒輪裝置完成其工作。這件驚人的齒輪已出現(xiàn)在《howstuffworks》中。你可以從《電動螺絲刀

34、》一文中得到查證。自動傳輸包含兩個完整的行星齒輪裝置，其折疊起來組成一個部分?？纯础洱X輪比如何實現(xiàn)》，介紹了行星齒輪裝置。   任何行星齒輪裝置有三個主要組成部分： ?太陽輪?行星齒輪和行星齒輪架?齒圈</p><p>　　上述這三個組成部分，可以保證輸入，輸出或平穩(wěn)運行。選擇哪一條路經決定著相應的傳動比。我們先來看看一個單一的行星齒輪裝置。 其中的行星齒輪裝置，有一個72齒的環(huán)形齒輪和30

35、齒的太陽齒輪。由這一裝置我們可以得到許多不同的傳動比。此外，鎖定三個組成部分的任何兩個，將組成一套傳動路徑，傳動比小于1:1。也就是說第一傳動比的輸出速度比輸入速度慢。二是一個過載輸出，輸出比輸入速度快。最后是倒檔，但輸出的方向正好相反。由這個行星齒輪組可以得到不同的傳動比，這就是有關我們的自動變速器。</p><p>　　這種自動變速器采用了一套齒輪，即所謂的復合型行星齒輪裝置，看上去像一個單行星齒輪裝置，但實

36、際上作用就像兩個行星齒輪裝置結合起來。它有一個始終輸出的環(huán)形齒輪，有兩個太陽齒輪和兩套行星。 </p><p>　　接下來你可以看到行星齒輪架里面的構造。較短的齒輪僅與較小的太陽輪嚙合。較長的行星齒輪與較大的太陽輪和較小的行星齒輪相嚙合。 </p><p>　　第一齒輪在第一擋，較小的太陽輪由變矩器中的渦輪順時針驅動。行星架試圖逆時針旋轉，但是由一個單向離合器（只允許將輪換在順時針方向

37、）和齒圈控制著輸出。小齒輪有30個齒，齒圈有72個，因此，傳動比是：Ratio = -R/S = - 72/30 = -2.4:1</p><p>　　傳動比為負值，這意味著輸出方向與輸入方向相反。但輸出的方向的確和輸入的方向相同，這是哪里出了問題呢？第一套行星齒輪與第二套行星齒輪相嚙合，而第二套驅動齒圈，這就使得方向相反了。你可以看到，這也將造成較大的太陽輪旋轉，但因為離合器的分離，大太陽齒輪可以自由的與渦輪發(fā)

38、生相反旋轉。</p><p>　　第二齒輪這種傳輸通過精巧的改變就能獲得理想的傳動比，即二檔。它的作用就像由行星架鏈接的兩個行星齒輪裝置。 實際上行星輪首先以較大的太陽輪作為齒圈。因此，第一階段由太陽輪（規(guī)模較小的太陽齒輪） ，行星架和齒圈（較大的太陽齒輪）組成 。 輸入是小太陽齒輪;齒圈（大太陽齒輪）由制動帶子固定不動，輸出則由行星架完成。這一階段，即太陽輪輸入，行星架輸出，齒圈固定，計算公式為：1

39、 + R/S = 1 + 36/30 = 2.2:1</p><p>　　行星架的轉速達到了小太陽輪的2.2倍。在第二階段，行星架作為第二行星齒輪裝置的輸入，大太陽齒輪為中心太陽輪，齒圈作為輸出，所以傳動比是： 1 / (1 + S/R) = 1 / (1 + 36/72) = 0.67:1</p><p>　　為得到第二檔的總傳動減少量，我們再乘以第一階傳動比，

40、為2.2 x 0.67 =1.47:1。這聽起來可能比較有趣的，但它確實如此。</p><p><b>　　第三齒輪</b></p><p>　　大部分自動變速器第三檔傳動比為1:1。從前面一節(jié)你會記得，為取得1:1的傳動比輸出，要做的就是鎖止3個部件的任意兩部分。有齒輪裝置的布置形式來實現(xiàn)這一目標顯得更加簡單---結合離合器，使每一個太陽輪都與渦輪結合。 如