【正文】 the output shaft to transmit power to the drive shaft (red arrow). The typical 1 speed gear transmission ratio is 3:1, that is to say 3 laps to the input shaft, output shaft 1 ring. When the growth rate of car drivers to choose the file 2, the 1\/2 File Synchronizer and 1 fork connection 2 gear on the output shaft and lock, power transmission line is similar, the 東北大學秦皇島分校畢業(yè)設計（論文） 第 31 頁difference is that the output shaft of the 1 gear change into 2 gear to drive the output shaft. The typical 2 speed gear transmission ratio is :1, laps to the input shaft, output shaft rotation 1 laps, 1 stall speed increase, and decrease the torque. When the car drivers option 3 refueling growth stalls, plectrum to 1\/2 File Synchronizer return to the neutral position, and also allows the 3\/4 File Synchronizer moving until the 3 locking gear on the output shaft, the power from the shaft into the shaft and intermediate shaft and output shaft of the 3 gear gearbox output shaft, moving through 3 gear transmission gear wheel. 3 typical gear ratio is :1, laps to the input shaft, output shaft to the 1 circle, is further growth. When the car drivers option 4 refueling growth stalls, the 3\/4 File Synchronizer Gear from 3 direct engagement with the input shaft of the driving gear shift fork, power transmission directly from the input shaft to the output shaft, the transmission ratio is 1:1, the output shaft and the input shaft speed. Because the power without intermediate shaft, also known as direct gear, the gear ratio of transmission efficiency. Most cars running time to achieve the best fuel economy with direct drive. Shift into the first interval when the transmission is in neutral gear, gear output shaft is not locked in, they can39。t drive the output shaft, power output is not. General automotive manual transmission ratio is mainly divided into the 1 4 grade, usually the first designers to determine the minimum (1) and the highest (4) transmission ratio, transmission middle stall by geometric progression than the general distribution. In addition, there are reverse and overdrive, also known as the 5 gear overdrive. When the car to accelerate to more than car drivers with 5 stalls, 5 stalls typical transmission ratio is :1, which is driven by a pinion gear, when the driving gear , gear has been turned over 1 times. Reverse the output shaft to rotate in the opposite direction. If a pair of meshing gears when we reverse rotation, the middle and the last gear will be rotated in the same direction. Using this principle, the reverse will add a gear to do media, the rotational direction reversed, it will have a Daodang axis. The reverse gear shaft independently installed in the transmission housing, and the intermediate shaft parallel axis gear, and the intermediate shaft and output shaft gear meshing, would be contrary to the output shaft. Control also joins 5 gear synchronizer gear used, so 5 speed and reverse position is on the same side. As a middle gear, the general transmission gear transmission ratio greater than 1 gear ratio, by twisting, some cars met steep slope with forward do not use reverse open up ride from the driver of the considerations, transmission shift more better, transmission gear multiple adjacent stall the ratio of small changes, shift easy and smooth. But a much drawback is the 東北大學秦皇島分校畢業(yè)設計（論文） 第 32 頁transmission of plex structure, large volume, now lightduty automotive transmission is usually 45 file. At the same time, the transmission ratio is not integer, but with a decimal point, this is because the number of teeth of gear is not multiple of the number of gear teeth caused by, two is integer times will result in a two meshing surface uneven wear, makes the quality of tooth surface have a greater difference.汽車換擋原理我們知道，汽車發(fā)動機在一定的轉(zhuǎn)速下能夠達到最好的狀態(tài)，此時發(fā)出的功率比較大，燃油經(jīng)濟性也比較好。因此，我們希望發(fā)動機總是在最好的狀態(tài)下工作。但是，汽車在使用的時候需要有不同的速度，這樣就產(chǎn)生了矛盾。這個矛盾要通過變速器來解決。 汽車變速器的作用用一句話概括，就叫做變速變扭，即增速減扭或減速增扭。為什么減速可以增扭，而增速又要減扭呢？設發(fā)動機輸出的功率不變，功率可以表示為 N = wT，其中 w 是轉(zhuǎn)動的角速度， T 是扭距。當 N 固定的時候，w 與 T 是成反比的。所以增速必減扭，減速必增扭。汽車變速器齒輪傳動就根據(jù)變速變扭的原理，分成各個檔位對應不同的傳動比，以適應不同的運行狀況。一般的手動變速器內(nèi)設置輸入軸、中間軸和輸出軸，又稱三軸式，另外還有倒檔軸。三軸式是變速器的主體結(jié)構，輸入軸的轉(zhuǎn)速也就是發(fā)動機的轉(zhuǎn)速，輸出軸轉(zhuǎn)速則是中間軸與輸出軸之間不同齒輪嚙合所產(chǎn)生的轉(zhuǎn)速。不同的齒輪嚙合就有不同的傳動比，也就有了不同的轉(zhuǎn)速。例如鄭州曰產(chǎn) ZN6481W2G 型 SUV 車手動變速器，它的傳動比分別是： 1 檔 :1；2 檔:1；3 檔 :1；4 檔 1:1；5 檔（超速檔）:1。當汽車啟動司機選擇 1 檔時，換擋叉將 1/2 檔同步器向后接合 1 檔齒輪并將它鎖定輸出軸上，動力經(jīng)輸入軸、中間軸和輸出軸上的 1 檔齒輪，1 檔齒輪帶動輸出軸，輸出軸將動力傳遞到傳動軸上（紅色箭頭） 。典型 1 檔變速齒輪傳動比是 3:1,也就是說輸入軸轉(zhuǎn) 3 圈，輸出軸轉(zhuǎn) 1 圈。當汽車增速司機選擇 2 檔時，換擋叉將 1/2 檔同步器與 1 檔分離后接合 2 檔齒輪并鎖定輸出軸上，動力傳遞路線相似，所不同的是輸出軸上的 1 檔齒輪換成 2 檔齒輪帶動輸出軸。典型 2 檔變速齒輪傳動比是 :1，輸入軸轉(zhuǎn) 圈，輸出軸轉(zhuǎn) 1 圈，比 1 檔轉(zhuǎn)速增加，扭矩降低。 當汽車加油增速司機選擇 3 檔時，換擋叉使 1/2 檔同步器回到空檔位置，又使 3/4 檔同步器移動直至將 3 檔齒輪鎖定在輸出軸上，使動力可以從軸入軸 —中間軸—輸出軸上的 3 檔變速齒輪，通過 3 檔變速齒輪帶動輸出軸。典型 3 檔傳動比是 東北大學秦皇島分校畢業(yè)設計（論文） 第 33 頁:1，輸入軸轉(zhuǎn) 圈，輸出軸轉(zhuǎn) 1 圈，是進一步的增速。當汽車加油增速司機選擇 4檔時，換擋叉將 3/4 檔同步器脫離 3 檔齒輪直接與輸入軸主動齒輪接合，動力直接從輸入軸傳遞到輸出軸，此時傳動比 1:1，即輸出軸與輸入軸轉(zhuǎn)速一樣。由于動力不經(jīng)中間軸，又稱直接檔，該檔傳動比的傳動效率最高。汽車多數(shù)運行時間都用直接檔以達到最好的燃油經(jīng)濟性。 換檔時要先進入空檔，變速器處于空檔時變速齒輪沒有鎖定在輸出軸上，它們不能帶動輸出軸轉(zhuǎn)動，沒有動力輸出。一般汽車手動變速器傳動比主要分上述 1－4 檔，通常設計者首先確定最低（1 檔）與最高（4 檔）傳動比后，中間各檔傳動比一般按等比級數(shù)分配。另外，還有倒檔和超速檔，超速檔又稱為 5 檔。當汽車要加速超過同向汽車時司機選擇 5 檔，典型 5 檔傳動比是 :1，也就是用大齒輪帶動小齒輪，當主動齒輪轉(zhuǎn) 圈時，被動齒輪已經(jīng)轉(zhuǎn)完 1 圈了。倒檔時輸出軸要向相反方向旋轉(zhuǎn)。如果一對齒輪嚙合時大家反向旋轉(zhuǎn)，中間加上一個齒輪就會變成同向旋轉(zhuǎn)。利用這個原理，倒檔就要添加一個齒輪做“媒介” ，將軸的轉(zhuǎn)動方向調(diào)轉(zhuǎn)，因此就有了一根倒檔軸。倒檔軸獨立裝在變速器殼內(nèi)，與中間軸平行，當軸上齒輪分別與中間軸齒輪和輸出軸齒輪嚙合時，輸出軸轉(zhuǎn)向會相反。 倒檔用的同步器也控制 5 檔的接合，所以 5 檔與倒檔位置是在同一側(cè)的。由于有中間齒輪，一般變速器倒檔傳動比大于 1 檔傳動比，增扭大，有些汽車遇到陡坡用前進檔上不去就用倒檔開上去從駕駛平順性考慮，變速器檔位越多越好，檔位多相鄰檔間的傳動比的比值變化小，換檔容易而且平順。但檔位多的缺點就是變速器構造復雜，體積大，現(xiàn)在輕型汽車變速器一般是 4－5 檔。同時，變速器傳動比都不是整數(shù)，而是都帶小數(shù)點的，這是因為嚙合齒輪的齒數(shù)不是整倍數(shù)所致，兩齒輪齒數(shù)是整倍數(shù)就會導致兩齒輪嚙合面磨損不均勻，使得輪齒表面質(zhì)量產(chǎn)生較大的差異。