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畢 業(yè) 設(shè) 計(jì)（論 文）外 文 參 考 資 料 及 譯 文 譯文題目： 汽車變速器設(shè)計(jì) 學(xué)生姓名： 學(xué) 號(hào)： 專 業(yè)： 所在學(xué)院： 指導(dǎo)教師： 職 稱： 20xx年 2月 27日 英文原文 Transmission design As we all know,automobile engine to a certain speed can be achieved under the best conditions, when compared issued by the power, fuel economy is relatively good. Therefore, we hope that the engine is always in the best of conditions to work under. However, the use of motor vehicles need to have different speeds, thus creating a conflict. Transmission through this conflict to resolve. Automotive Transmission role sum up in one sentence, called variable speed twisting, twisting or slow down the growth rate by increasing torsional. Why can slow down by twisting, and the growth rate but also by twisting? For the same engine power output, power can be expressed as N = wT, where w is the angular velocity of rotation, and T is the torque. When N fixed, w and T is inversely proportional to the. Therefore, the growth rate will reduce twisting, twisting slowdown will increase. Automotive Transmission speed gear based on the principle of variable twisted into various stalls of different transmission ratio corresponding to adapt to different operational conditions. General to set up a manual gearbox input shaft, intermediate shaft and output shaft, also known as the three-axis, as well as the reverse gear shaft. Three-axis is the main transmission structure, input shaft speed is the speed of the engine, the output shaft speed is the intermediate shaft and output shaft gear meshing between different from the speed. Different gears are different transmission ratio, and will have a different speed. For example, the Nissan ZN6481W2G SUV car manual transmission, its transmission ratio are: 1 File 3.704:1; 2 stalls 2.202:1;3 stalls 1.414:1; 4 stalls 1:1; 5 stalls (speeding file) 0.802: 1. When drivers choose a launch vehicle stalls, Plectrum will be 1 / 2 file synchronization engagement with a back stall gear and output shaft lock it, the power input shaft, intermediate shaft and output shaft gear of a stall, a stall the output shaft gear driven, and the output shaft power will be transmitted to the drive shaft . 1 shifting speed gear transmission ratio is 3:1, that is to say three laps to the input shaft and output shaft to a circle. When the growth rate of car drivers choose two stalls, Plectrum will be 1 / 2-file synchronization and file a joint separation after 2 stall and lock the output shaft gear, power transmission line similar, the difference is that the output shaft gear of a stall 2 stall replaced by the output shaft gear driven. Band 2 speed gear transmission ratio is 2.2 :1, 2.2 laps to the input shaft and output shaft to a circle than a stall speed increase, lower torque. When refueling vehicle drivers growth stalls option 3, Plectrum to 1 / 2 back to the free file-synchronization position, and also allows the 3 / 4 file synchronization Mobile stall until 3 in the output shaft gear lock, power can be into the shaft axis intermediate shaft - the output shaft of the three stalls speed gear, led through three stalls speed gear output shaft. 3 stalls typical transmission ratio is 1.7:1, 1.7 laps to the input shaft and output shaft to a circle is further growth. When car drivers Option 4 refueling growth stalls, Plectrum will be 3 / 4 from the 3-file synchronization stall gear directly with the input shaft gear joint initiative, and power transmission directly from the input shaft to the output shaft, the transmission ratio at 1:1, that the input shaft and output shaft speed the same. The driving force without intermediate shaft, also known as direct file, the file transmission than the maximum transmission efficiency. Most cars run-time files are used directly to achieve the best fuel economy. Shift into the first interval when, in a free transmission when the speed gear output shaft is not locked in, they can not rotate the output shaft driven, not power output. General automotive manual transmission than the main 1-4 stalls, usually the first designers to determine the minimum (one stall) and maximum (4 files) transmission ratio, the middle stall drive by geometric progression than the general distribution. In addition, Also have a reverse and overdrive, overdrive is also known as the five stalls. When the car to accelerate to more than car drivers with the choice of five stalls, and a typical five-transmission ratio is 0.87:1, which is driven by a pinion gear, the gear when the initiative to 0.87 zone, passive gear have been transferred to a circle of the End. When the reverse gear output shaft to rotate in opposite directions. If one pair of meshing gears when we reverse rotation, with a middle gear, it will become the same to the rotation. Use of this principle, reverse will add a gear do "media interface", modulate the axis rotation direction, therefore there is a bone in the reverse gear shaft.Independent in the reverse gear shaft gearbox, parallel to the intermediate shaft, when the shaft gear respectively with intermediate shaft gear and the output shaft gear meshing, the output shaft will turn to instead. The reverse usually used for the synchronization control also joins five stalls, reverse and 5 position in the same side. As a middle gear, general transmission shifting gear ratio is greater than 1 transmission ratio, increasing twist, some car encounter to the steep slope with the forward couldn't get on with the reverse open up. Ride from the driver of the considerations, better transmission stall, stall adjacent stall more than the transmission changes the ratio of small, and easy to shift smoothly. However, the shortcomings of the stalls is more transmission structure is complicated, bulky, light vehicle transmission is generally 4-5 stalls. At the same time, transmission ratio is not integral, but with all of the decimal point, it is because of the gear teeth meshing is not caused by the whole multiples of two gear teeth can lead to the whole multiples of two meshing gears of uneven wear, making the tooth surface quality have a greater difference. Manual transmission and synchronizer Manual transmission is the most common transmission, or MT. Its basic structure sum up in one sentence, is a two-axle shaft, where input shaft, the shaft axis and intermediate shaft, which constitute the main body of the transmission and, Of course also have a reverse axis. Manual transmission known as manual gear transmission, which can be in the axial sliding gears, the gears meshing different variable speed reached twisting purpose. Typical manual transmission structure and principles are as follows. Input shaft also said that the first axis, and its front-end Spline driven directly with the clutch disc sets with the Spline, by the transfer of torque from the engine. The first axis of the intermediate shaft and gears meshing gears often, as long as the shaft axis to a turn, the intermediate shaft and gear also will be rotating. Vice also said intermediate shaft axis, the axis-even more than the size gear. Also known as the second output shaft axis, the axis of various sets of gear stall progress can be manipulated at any time in the role of the device and the corresponding intermediate shaft gear meshing, thus changing its speed and torque. With the end of the output shaft spline associated with the drive shaft through the drive shaft torque transmitted to the drive axle reducer. Thus, progress stalls drive transmission path is: input shaft gear often rodents often rodents intermediate shaft gear - corresponding intermediate shaft gear - the second axis corresponding gear. Reversing the gear shaft can be manipulated by the device pick in the axis movement, and the intermediate shaft and output shaft gear meshing gears, to the contrary to the direction of rotation output. Most cars have a five forward gears and one reverse gear, a certain degree of each stall transmission ratio, the majority of stalls transmission ratio greater than 1, 4 file transmission ratio of 1, known as direct stalls, and transmission ratio is less than 1 No. 5 stall called accelerated stall. Free at the output shaft gear in a position of non-engagement, unacceptable power transmission. The transmission input shaft and output shaft rotational speed to their own, transform a stall when there is a "synchronous". Two different rotational speed gear meshing force will impact the collision occurred, damage gear. Therefore, the old transmission shift to a "feet-off" approach, or stall on the location of the free stay for a while by stalls in the free position refueling doors, in order to reduce the speed differential gear. However, this operation is relatively more complicated and difficult to grasp accurate. So designers create a "synchronized," and allows synchronization through the meshing of gears to be consistent speed and smooth meshing. At present Synchronous Transmission is based on the synchronization of inertia, mainly from joint sets, synchronous lock ring, and so on, it is characterized by friction on the role of synchronization. Splice sets Genlock engagement ring gear and the ring gear when it had Chamfer (Lock angle), Genlock within the cone ring gear engagement with the question of cone ring gear contact friction. Lock and cone angle has been made in the design of an appropriate choice to be made friction cone of the teeth meshing with the ring gear quickly sets pace at the same time will have a Lock role and to prevent the gears meshing in sync before. When synchronization lock cone ring gear engagement with the question of cone ring gear after contact in the effects of friction torque gear speed quickly lower (or higher) with the same speed synchronous lock ring, the two synchronous rotation of the gear Genlock Central zero speed, thus moment of inertia also disappear, then in force under the impetus of engagement sets unhindered and synchronization lock ring gear engagement, and further engagement with the question of gear engagement and the completion Gear Shift Process. The automatic gearbox The automatic gearbox chooses to block the pole the equal to moving the stick shift of the gearbox, having generally below several blocks:P( parking), R( pour to block), N( get empty to block), D( go forward), S( or2, namely for 2 block soon), L.( or1, namely for 1 block soon)This several an usage for blocking a right usages coming driver the automatic gearbox is automotive of person to say particularly important, underneath let us very much familiar with once automatic gearbox eachly blockings main theme. The usage of the P ( the parking blocks) The launches the luck turns as long as choose to block the pole in driving the position, automatic gearbox car run about very easily.But park, choose to block the pole must pull into of P, from but pass the internal parking system in gearbox moves the device will output the stalk lock lives, combining to tense the hand system move, preventing the car ambulation. The usage of the R( pour to block) R a control for is pouring blocking, using inside wanting slicing recording, automatic gearbox car unlike moving gearbox car so can using half moving, so while reversing the car wanting special attention accelerating pedal. The usage of the N( get empty to block) The N is equal to get empty to block, can while starting or hour of trailer usage.At wait for the signal or block up the car will often often choose to block the pole keeps in the of D, trampling at the same time the next system move.If time is very short, do like this is an admission of, but if stop the time long time had better change into of N, combine to tense the hand system moves.Because choose to block the pole in driving the position, the automatic gearbox car has generally and all to drive the trend faintly, long hours trample the system move same as a deterrent this kind of trend, make gearbox oil gone up, the oil liquid changes in character easily.Particularly in the air condition machine work, launch the soon higher circumstance in machine bottom more disadvantageous.Some pilots for the sake of stanza oil, at made good time or go down slope will choose to block the pole pull the of N skids, this burn the bad gearbox very easily, launching the machine to revolves soon in the however because the gearbox outputs at this time the stalk turns soon very high,, the oil pump provides the oil shortage, lubricating the condition worsen, burn the bad gearbox easily. The usage of the D( go forward to block) Will choose to block when is normal to drive the pole put in the of D, car can at 1 ～ 4 block( or 3 block) its change to block automatically.The of D drives the position most in common usely.What demand control is:Because the automatic gearbox is soon high and low with car to come to make sure to block according to the accelerator size a, so accelerate the pedal operation method is different, changing to block the hour of the car is soon too not same alike.If start hour quick accelerate the pedal tramples the bottom, rising to block the night, accelerating the ability is strong, arriving certain car soon behind, then will accelerate the pedal loosen to open very quickly, car can rise to block immediately, launch like this the machine voice is small, comfortable good. The another characteristics of the D is a compulsory low blocking, easy to high speed the hour overtakes a car, will accelerate quickly in of D drove the pedal trample after all, connect the compulsory low fend off the pass and then can reduce to block automatically, the car accelerates very quickly, after overtaking a car loosen to open the pedal of acceleration to can rise to block automatically again. The usage of the S, of L low the usage that block The automatic gearbox in in is placed in the low blocking the scope on of S or of Ls, can usage under an etc. circumstance.It change to can make use of to launch well into of S or of Ls the mechanism move, avoiding the car wheel system move the machine over hot, cause the system move the effect descent while going down slope.But change into from the of D of S or of L, car soon can't higher than rise to block the car homologously soon, otherwise strong vibration in opportunity to launch, make gearbox oil hoicked, even will damage the gearbox. The is another at rain fog weather hour, if the road adheres to the term bad, can change into a position for or of L, fixing at somely first lowly blocking driving, doing not use can automatically changing blocking, in order to prevent the car beats slippery.Must keep firmly in mind at the same time, beat the slippery hour can will choose to block the pole pushes into a motive for, cutting off launching machine, toing guarantee a car the safety. 中文譯文 汽車變速器設(shè)計(jì) 我們知道，汽車發(fā)動(dòng)機(jī)在一定的轉(zhuǎn)速下能夠達(dá)到最好的狀態(tài)，此時(shí)發(fā)出的功率比較大，燃油經(jīng)濟(jì)性也比較好。因此，我們希望發(fā)動(dòng)機(jī)總是在最好的狀態(tài)下工作。 但是，汽車在使用的時(shí)候需要有不同的速度，這樣就產(chǎn)生了矛盾。這個(gè)矛盾要通 過(guò)變速器來(lái)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(shè)發(fā)動(dòng)機(jī)輸出的功率不變，功率可以 表示為 N = wT，其中 w 是轉(zhuǎn)動(dòng)的角速度，T 是扭距。當(dāng) N 固定的時(shí)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(dòng)就根據(jù)變速變扭 的原理，分成各個(gè)檔位對(duì)應(yīng)不同的傳動(dòng)比，以適應(yīng)不同的運(yùn)行狀況。 一般的手動(dòng)變速器內(nèi)設(shè)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(gòu)，輸入軸的轉(zhuǎn)速也就是發(fā)動(dòng)機(jī)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(dòng)比，也就有了不同的轉(zhuǎn)速。例如日產(chǎn) ZN6481W2G 型 SUV 車手動(dòng) 變速器，它的傳動(dòng)比分別是：1 檔 3.704:１；2 檔 2.202:1；3 檔 1.414:1；4 檔 1:1；5 檔（超速檔）0.802:1。 當(dāng)汽車啟動(dòng)司機(jī)選擇 1 檔時(shí)，撥叉將 1/2 檔同步器向后接合 1 檔齒輪并將它 鎖定輸出軸上，動(dòng)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(dòng)輸 出軸，輸出軸將動(dòng)力傳遞到傳動(dòng)軸上。典型 1 檔變速齒輪傳動(dòng)比是 3:1,也就是說(shuō)輸入軸轉(zhuǎn) 3 圈，輸出軸轉(zhuǎn) 1 圈。 當(dāng)汽車增速司機(jī)選擇 2 檔時(shí)，撥叉將 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(dòng)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(dòng)輸出軸。典型 2 檔變速齒輪傳動(dòng)比是 2.2:1，輸入軸轉(zhuǎn) 2.2 圈，輸出軸 轉(zhuǎn) 1 圈，比 1 檔轉(zhuǎn)速增加，扭矩降低。 當(dāng)汽車加油增速司機(jī)選擇 3 檔時(shí)，撥叉使 1/2 檔同步器回到空檔位置，又使 3/4 檔同步器移動(dòng)直至將 3 檔齒輪鎖定在輸出軸上，使動(dòng)力可以從軸入軸—中間 軸—輸出軸上的 3 檔變速齒輪，通過(guò) 3 檔變速齒輪帶動(dòng)輸出軸。典型 3 檔傳動(dòng)比 是 1.7:1，輸入軸轉(zhuǎn) 1.7 圈，輸出軸轉(zhuǎn) 1 圈，是進(jìn)一步的增速。 當(dāng)汽車加油增速司機(jī)選擇 4 檔時(shí)，撥叉將 3/4 檔同步器脫離 3 檔齒輪直接與 輸入軸主動(dòng)齒輪接合，動(dòng)力直接從輸入軸傳遞到輸出軸，此時(shí)傳動(dòng)1:1，即輸出軸與輸入軸轉(zhuǎn)速一樣。由于動(dòng)力不經(jīng)中間軸，又稱直接檔，該檔傳動(dòng)比的傳動(dòng) 效率最高。汽車多數(shù)運(yùn)行時(shí)間都用直接檔以達(dá)到最好的燃油經(jīng)濟(jì)性。 換檔時(shí)要先進(jìn)入空檔，變速器處于空檔時(shí)變速齒輪沒(méi)有鎖定在輸出軸上，它 們不能帶動(dòng)輸出軸轉(zhuǎn)動(dòng)，沒(méi)有動(dòng)力輸出。 一般汽車手動(dòng)變速器傳動(dòng)比主要分上述 1－4 檔， 通常設(shè)計(jì)者首先確定最低 （1 檔）與最高（4 檔）傳動(dòng)比后，中間各檔傳動(dòng)比一般按等比級(jí)數(shù)分配。另外，還 有倒檔和超速檔，超速檔又稱為 5 檔。 當(dāng)汽車要加速超過(guò)同向汽車時(shí)司機(jī)選擇 5 檔，典型 5 檔傳動(dòng)比0.87:1，也就是用大齒輪帶動(dòng)小齒輪，當(dāng)主動(dòng)齒輪轉(zhuǎn) 0.87 圈時(shí)，被動(dòng)齒輪已經(jīng)轉(zhuǎn)完 1 圈了。 倒檔時(shí)輸出軸要向相反方向旋轉(zhuǎn)。如果一對(duì)齒輪嚙合時(shí)大家反向旋轉(zhuǎn)，中間 加上一個(gè)齒輪就會(huì)變成同向旋轉(zhuǎn)。利用這個(gè)原理，倒檔就要添加一個(gè)齒輪做“媒 介”，將軸的轉(zhuǎn)動(dòng)方向調(diào)轉(zhuǎn)，因此就有了一根倒檔軸。倒檔軸獨(dú)立裝在變速器殼 內(nèi)，與中間軸平行，當(dāng)軸上齒輪分別與中間軸齒輪和輸出軸齒輪嚙合時(shí)，輸出軸 轉(zhuǎn)向會(huì)相反。 通常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(dòng)比大于 1 檔傳動(dòng)比，增扭大，有些汽車遇 到陡坡用前進(jìn)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(dòng)比的比值 變化小，換檔容易而且平順。但檔位多的缺點(diǎn)就是變速器構(gòu)造復(fù)雜，體積大，現(xiàn)在輕型汽車變速器一般是 4－5 檔。同時(shí)，變速器傳動(dòng)比都不是整數(shù)，而是都帶小數(shù)點(diǎn)的，這是因?yàn)閲Ш淆X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(huì)導(dǎo) 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。 手動(dòng)變速器與同步器 手動(dòng)變速器是最常見的變速器，簡(jiǎn)稱 MT。它的基本構(gòu)造用一句話概括，就是 兩軸一中軸，即指輸入軸、軸出軸和中間軸，它們構(gòu)成了變速器的主體，當(dāng)然還 有一根倒檔軸。 手動(dòng)變速器又稱手動(dòng)齒輪式變速器， 含有可以在軸向滑動(dòng)的齒輪， 通過(guò)不同齒輪的嚙合達(dá)到變速變扭目的。典型的手動(dòng)變速器結(jié)構(gòu)及原理如下。 輸入軸也稱第一軸，它的前端花鍵直接與離合器從動(dòng)盤的花鍵套配合，從而 傳遞由發(fā)動(dòng)機(jī)過(guò)來(lái)的扭矩。第一軸上的齒輪與中間軸齒輪常嚙合，只要軸入軸一 轉(zhuǎn)，中間軸及其上的齒輪也隨之轉(zhuǎn)動(dòng)。中間軸也稱副軸，軸上固連多個(gè)大小不等 的齒輪。輸出軸又稱第二軸，軸上套有各前進(jìn)檔齒輪，可隨時(shí)在操縱裝置的作用 下與中間軸的對(duì)應(yīng)齒輪嚙合，從而改變本身的轉(zhuǎn)速及扭矩。輸出軸的尾端有花鍵 與傳動(dòng)軸相聯(lián)，通過(guò)傳動(dòng)軸將扭矩傳送到驅(qū)動(dòng)橋減速器。 由此可知，變速器前進(jìn)檔位的驅(qū)動(dòng)路徑是：輸入軸常嚙齒輪－中間軸常嚙齒輪－中間軸對(duì)應(yīng)齒輪－第二軸對(duì)應(yīng)齒輪。 倒車軸上的齒輪也可以由操縱裝置撥動(dòng)，在軸上移動(dòng)，與中間軸齒輪和輸出軸齒輪嚙合,以相反的旋轉(zhuǎn)方向輸出。 多數(shù)汽車都有 5 個(gè)前進(jìn)檔和一個(gè)倒檔，每個(gè)檔位有一定的傳動(dòng)比，多數(shù)檔位 傳動(dòng)比大于 1，第 4 檔傳動(dòng)比為 1，稱為直接檔，而傳動(dòng)比小于 1 的第 5 檔稱為加 速檔?？諜n時(shí)輸出軸的齒輪處于非嚙合位置，無(wú)法接受動(dòng)力傳輸。 由于變速器輸入軸與輸出軸以各自的速度旋轉(zhuǎn)，變換檔位時(shí)合存在一個(gè)"同步 "問(wèn)題。兩個(gè)旋轉(zhuǎn)速度不一樣齒輪強(qiáng)行嚙合必然會(huì)發(fā)生沖擊碰撞，損壞齒輪。因此，舊式變速器的換檔要采用"兩腳離合"的方式，升檔在空檔位置停留片刻，減檔要在空檔位置加油門，以減少齒輪的轉(zhuǎn)速差。但這個(gè)操作比較復(fù)雜，難以掌握精確。因此設(shè)計(jì)師創(chuàng)造出"同步器"，通過(guò)同步器使將要嚙合的齒輪達(dá)到一致的轉(zhuǎn)速而順利嚙合。 目前全同步式變速器上采用的是慣性同步器，它主要由接合套、同步鎖環(huán)等 組成，它的特點(diǎn)是依靠摩擦作用實(shí)現(xiàn)同步。接合套、同步鎖環(huán)和待接合齒輪的齒 圈上均有倒角（鎖止角），同步鎖環(huán)的內(nèi)錐面與待接合齒輪齒圈外錐面接觸產(chǎn)生 摩擦。鎖止角與錐面在設(shè)計(jì)時(shí)已作了適當(dāng)選擇，錐面摩擦使得待嚙合的齒套與齒 圈迅速同步，同時(shí)又會(huì)產(chǎn)生一種鎖止作用，防止齒輪在同步前進(jìn)行嚙合。當(dāng)同步 鎖環(huán)內(nèi)錐面與待接合齒輪齒圈外錐面接觸后，在摩擦力矩的作用下齒輪轉(zhuǎn)速迅速 降低（或升高）到與同步鎖環(huán)轉(zhuǎn)速相等，兩者同步旋轉(zhuǎn)，齒輪相對(duì)于同步鎖環(huán)的 轉(zhuǎn)速為零，因而慣性力矩也同時(shí)消失，這時(shí)在作用力的推動(dòng)下，接合套不受阻礙 地與同步鎖環(huán)齒圈接合，并進(jìn)一步與待接合齒輪的齒圈接合而完成換檔過(guò)程。 自動(dòng)變速器 自動(dòng)變速器的選擋桿相當(dāng)于手動(dòng)變速器的變速桿， 一般有以下幾個(gè)擋位： P(停 車)、R(倒擋)、N(空擋)、D(前進(jìn))、S(or2，即為 2 速擋)、L(or1，即為 1 速擋)。 這幾個(gè)擋位的正確使用對(duì)于駕駛自動(dòng)變速器汽車的人來(lái)說(shuō)尤其重要，下面就讓我 們一起來(lái)熟悉一下自動(dòng)變速器各擋位的使用要領(lǐng)。 ●P(停車擋)的使用 發(fā)動(dòng)機(jī)運(yùn)轉(zhuǎn)時(shí)只要選擋桿在行駛位置上，自動(dòng)變速器汽車就很容易地行走。 而停放時(shí)，選擋桿必須扳入 P 位，從而通過(guò)變速器內(nèi)部的停車制動(dòng)裝置將輸出軸 鎖住，并拉緊手制動(dòng)，防止汽車移動(dòng)。  ●R(倒擋)的使用 R 位為倒擋，使用中要切記，自動(dòng)變速器汽車不像手動(dòng)變速器汽車那樣能夠 使用半聯(lián)動(dòng)，故在倒車時(shí)要特別注意加速踏板的控制。 ●N(空擋)的使用 N 位相當(dāng)于空擋，可在起動(dòng)時(shí)或拖車時(shí)使用。在等待信號(hào)或堵車時(shí)常常將選 擋桿保持在 D 位，同時(shí)踩下制動(dòng)。若時(shí)間很短，這樣做是允許的，但若停止時(shí)間 長(zhǎng)時(shí)最好換入 N 位，并拉緊手制動(dòng)。因?yàn)檫x擋桿在行駛位置上，自動(dòng)變速器汽車 一般都有微弱的行駛趨勢(shì)，長(zhǎng)時(shí)間踩住制動(dòng)等于強(qiáng)行制止這種趨勢(shì)，使得變速器 油溫升高，油液容易變質(zhì)。尤其在空調(diào)器工作、發(fā)動(dòng)機(jī)怠速較高的情況下更為不 利。有些駕駛員為了節(jié)油，在高速行駛或下坡時(shí)將選擋桿扳到 N 位滑行，這很容 易燒壞變速器，因?yàn)檫@時(shí)變速器輸出軸轉(zhuǎn)速很高，而發(fā)動(dòng)機(jī)卻在怠速運(yùn)轉(zhuǎn)，油泵 供油不足，潤(rùn)滑狀況惡化，易燒壞變速器。  ●D(前進(jìn)擋)的使用 正常行駛時(shí)將選擋桿放在 D 位，汽車可在 1～4 擋(或 3 擋)之間自動(dòng)換擋。D 位是最常用的行駛位置。需要掌握的是：由于自動(dòng)變速器是根據(jù)油門大小與車速 高低來(lái)確定擋位的，所以加速踏板操作方法不同，換擋時(shí)的車速也不相同。如果 起步時(shí)迅速將加速踏板踩下，升擋晚，加速能力強(qiáng)，到一定車速后，再將加速踏 板很快松開，汽車就能立即升擋，這樣發(fā)動(dòng)機(jī)噪聲小，舒適性好。 D 位的另一個(gè)特點(diǎn)是強(qiáng)制低擋，便于高速時(shí)超車，在 D 位行駛中迅速將加速 踏板踩到底，接通強(qiáng)制低擋開關(guān)就能自動(dòng)減擋，汽車很快加速，超車之后松開加 速踏板又可自動(dòng)升擋。  ●S、L 位低擋的使用 自動(dòng)變速器在 S 位或 L 位上處于低擋范圍，可以在坡道等情況下使用。下坡 時(shí)換入 S 位或 L 位能充分利用發(fā)動(dòng)機(jī)制動(dòng)，避免車輪制動(dòng)器過(guò)熱，導(dǎo)致制動(dòng)效能 下降。但是從 D 位換入 S 位或 L 位時(shí)，車速不能高于相應(yīng)的升擋車速，否則發(fā)動(dòng) 機(jī)會(huì)強(qiáng)烈振動(dòng)，使變速器油溫急劇上升，甚至?xí)p壞變速器。 另外在雨霧天氣時(shí)，若路面附著條件差，可以換入 S 位或 L 位，固定在某一 低擋行駛，不要使用能自動(dòng)換擋的位置，以免汽車打滑。同時(shí)必須牢記，打滑時(shí)可將選擋桿推入 N 位，切斷發(fā)動(dòng)機(jī)的動(dòng)力，以保證行車安全。