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科技譯文
題 目 汽車差速器的發(fā)展史
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汽車差速器的發(fā)展史
在火車和汽車出現(xiàn)之前，馬車一直都是人們出行十分重要交通工具。人們喜歡乘坐馬車從容地穿過鄉(xiāng)村的大道或古舊的城區(qū)街巷去拜訪朋友。追溯以往，我們已經(jīng)沒有辦法知道是誰第一個發(fā)明了車輪子，誰又造出了第一輛帶輪子的車輛。雖然車輪技術(shù)在初期并不太理想，但是它的出現(xiàn)還是提高了人類搬運(yùn)物品的速度，促進(jìn)了人類的發(fā)展。公元前2000年，有的部落開始用馬來拉有輪子的車，這種車輪已經(jīng)開始像圓形，而不是早期車輪那樣以整個木頭塊做成的。約公元前1世紀(jì)，羅馬制車匠發(fā)明了四輪馬車并逐漸加以改進(jìn)，使得四輪馬車可以以前輪為導(dǎo)向前進(jìn)。為了讓四輪馬車的性能更高，他們在車輪上鑲嵌金邊用來減少車輪與車體的摩擦。此后這種用作長途運(yùn)輸?shù)鸟R拉車成為各國主要的運(yùn)輸車輛。它的優(yōu)點(diǎn)是運(yùn)輸量大和運(yùn)行平穩(wěn)，缺點(diǎn)是需要較為平坦的路面才能行駛。隨著用于四輪馬車行駛的道路年久失修，人們又改用實(shí)用的兩輪車，因為它可以在崎嶇的地形條件能夠行駛。后來經(jīng)過再次改進(jìn)，但人們對四輪馬車的速度始終不能滿意，希望發(fā)明一種比馬更有耐力和更強(qiáng)壯的動力機(jī)器，以使車輪能夠轉(zhuǎn)得更快。
幾千年后，在英國和美國的一些地方，少數(shù)人開始試驗用蒸汽做動力，以鋼鐵做道路。蒸汽火車便這樣出現(xiàn)了，它的使用大大縮短了人們遠(yuǎn)程旅行的時間。不過由于鐵軌鋪設(shè)的限制，人們?nèi)ゴ蠖鄶?shù)地方還只有依靠馬車。為了解決這個問題，尋找一種能夠完全替代馬車的物品，發(fā)明家們又開始忙碌了起來。后來經(jīng)過不懈努力，卡爾·本茨研發(fā)出了一種能夠代替馬車的，就是由鋼鐵制成的三輪汽車。本茨發(fā)明的三輪汽車裝載量只相當(dāng)于兩輪馬車，并沒有舒適的車箱可供乘客遮風(fēng)擋雨，不能獲得大家認(rèn)可?？山鹱釉缤矶紩l(fā)光的，不久有人對三輪汽車進(jìn)行了改造，將它變?yōu)榱怂膫€輪子，并且具有像馬車一樣的帶窗箱子，還讓它有了一個好聽的名字“無馬馬車”。
在這種四輪汽車出現(xiàn)后，它與四輪馬車最大不同的地方在于轉(zhuǎn)彎的時候。四輪馬車在轉(zhuǎn)彎的時候是控制馬拖動改變前面兩個輪子的前進(jìn)方向，再由與兩個前輪相連接的車箱拖動后輪進(jìn)行轉(zhuǎn)向運(yùn)動。由于馬是動力的來源，前輪只是被馬拖著完成轉(zhuǎn)向的，后輪通過車體帶動完成的，所以不存在轉(zhuǎn)向困難的問題。而汽車的結(jié)構(gòu)則完全不同，它將發(fā)動機(jī)安裝在車身上，但是驅(qū)動汽車前進(jìn)的力卻必須直接傳送到輪子上。動力傳遞要經(jīng)過離合器、變速器、萬向節(jié)、傳動軸等裝置。這樣汽車的前輪與后輪之間就多出來了一根杠桿，而杠桿只能以一種速度傳給后面的兩個輪，這樣的直接后果就是后輪不能以不同速度轉(zhuǎn)動，就會造成轉(zhuǎn)彎困難。
若汽車順利轉(zhuǎn)彎，兩個后輪就不能以相同的速度轉(zhuǎn)動。汽車在轉(zhuǎn)彎的時候，車輪的行駛軌跡是一個圓弧，如果向左轉(zhuǎn)彎，圓弧的中心點(diǎn)就在左側(cè)，同一時間，右側(cè)輪子走的弧線就比左側(cè)輪子長。汽車轉(zhuǎn)彎時要平衡左右輪的差異，右側(cè)的輪子轉(zhuǎn)的快一點(diǎn)，左側(cè)的輪子轉(zhuǎn)的慢一點(diǎn)，用轉(zhuǎn)速的不同來彌補(bǔ)距離上的差異。
汽車工程師為了解決這個問題。他們先是試著讓兩個后輪不再使用一根杠桿進(jìn)行連接而是斷開，讓兩個后輪獨(dú)自擁有一根杠桿，也就是兩個獨(dú)立的軸，就是半軸。只要對兩個半軸上的杠桿分別施以不同的力量，就能使得左右兩個車輪具有不同的轉(zhuǎn)速。斷開后麻煩就來了，汽車只有一根傳動軸，怎么能分別給兩個半軸合理傳輸動力呢?這就需要一個裝置來做中間“人”。先用兩根杠桿在垂直角度與兩個連接后輪的杠桿相連，然后再通過一個杠桿在水平的位置與垂直的位置兩個杠桿相交，從而帶動兩個后輪的轉(zhuǎn)動。這樣的連接方式雖然可以使得兩個后輪進(jìn)行轉(zhuǎn)動，但不能實(shí)現(xiàn)兩個車輪以不同的速度轉(zhuǎn)動，因為它們實(shí)際的意義上還是一個整體。經(jīng)過不斷的實(shí)驗發(fā)現(xiàn)，在連接兩個后輪的杠桿上各安裝一個十字杠桿，并且與它們的垂直角度也安裝一個相同的十字杠桿，并用這個十字杠桿來帶動兩個輪上的十字杠桿。隨著垂直角度的十字杠桿的轉(zhuǎn)動，中間的這個十字杠桿并不會在同一時間內(nèi)帶動連接兩個后輪的十字杠桿，從而實(shí)現(xiàn)了兩個車輪處于有不同的轉(zhuǎn)速。
這樣雖然能解決了兩后輪不同轉(zhuǎn)速的問題，但是十字杠桿的空間過大，三個十字杠桿就容易出現(xiàn)帶動困難的情況。后又在十字杠桿的基礎(chǔ)上增加更多的杠桿，總共增加到了十二根，就形成了三個有十二根杠桿的風(fēng)車輪，這樣三個風(fēng)車輪都能夠很好的轉(zhuǎn)動。解決方案的模型已經(jīng)造出，總不可能在汽車上直接就安裝吧。在機(jī)械上與風(fēng)車輪具有相同功能的就是齒輪，而且齒輪可以根據(jù)需要打造更多的齒進(jìn)行咬合，使用壽命還比較長，出現(xiàn)脫落的機(jī)率微乎其微，完全是實(shí)現(xiàn)這個模型的最佳選擇。
當(dāng)時這樣的設(shè)計只是簡單的完成了原始的方案，并沒有實(shí)際上應(yīng)用到汽車上。就像任何一幅大作都需要畫龍點(diǎn)睛的一筆，完成這一筆的人就是法國雷諾汽車的創(chuàng)始人路易斯·雷諾。雷諾在看到了這個原始的設(shè)計后，要想若將它應(yīng)用到汽車上還需要改進(jìn)才行。不光需要齒輪緊緊咬合，還需要使齒輪可以隨著其他齒輪一起轉(zhuǎn)動，但齒輪還不能太多，六個就足夠。東西是有了，還是應(yīng)該給它取個好聽的名字，“差速器”就不錯，形象而且生動。
就這樣，解決汽車轉(zhuǎn)彎問題的差速器誕生了。在此后的一百多年里，汽車外觀和其他部件換了一代又一代，但這個關(guān)鍵部件還是沒有多大的改變，因為它的組成原理注定了它就是那個樣子。什么樣子呢?簡單一點(diǎn)的說就是由六個齒輪所組成。復(fù)雜一點(diǎn)，就是由一組行星齒輪組成，核心是兩個行星齒輪和兩個與左右后輪傳動軸相連接的半軸齒輪。什么是行星齒輪?在浩瀚的宇宙中，有這樣一種星球，它不僅圍繞著自己的軸線進(jìn)行轉(zhuǎn)動，而且還圍繞著其他的星球進(jìn)行轉(zhuǎn)動。如地球，地球就是一個行星。不僅要自轉(zhuǎn)，還要圍繞著太陽進(jìn)行不停地公轉(zhuǎn)。明白了什么是行星后，就容易理解行星齒輪了。行星齒輪是指那些不僅自身要轉(zhuǎn)動，而且還要圍繞著其他齒輪轉(zhuǎn)動的齒輪。差速器是由六個齒輪組成的，兩個行星齒輪+兩個半軸齒輪=四個齒輪，還有兩個。剩下的這兩個齒輪就是負(fù)責(zé)與傳動桿連接的，將發(fā)動機(jī)輸出的動力，在經(jīng)過了變速箱和傳動軸順利的交接給差速器，再由差速器根據(jù)實(shí)際的情況將動力分配到左右兩個后輪。只有將差速器安裝在傳動桿與兩個后輪半軸之間才可以實(shí)現(xiàn)合理的控制車輪的轉(zhuǎn)速，從而實(shí)現(xiàn)兩個車輪具有不同速度的目的。在將這六個齒輪安裝到相應(yīng)位置后，總不能讓它們裸露在外吧，還需要安一個遮風(fēng)擋雨的保護(hù)殼，以保護(hù)齒輪不受到其他位置零部件的干擾。為了節(jié)省空間，現(xiàn)代的差速器很少再使用經(jīng)典的平面齒輪了，更多的是使用曲齒圓錐齒輪、交錯軸斜齒輪、準(zhǔn)雙曲面齒輪甚至蝸桿，但基本的六個齒輪的結(jié)構(gòu)一直延續(xù)了下來。
History of automotive differential
Before the advent of the train and bus, coach has been very important for people to travel transportation. People like to take a leisurely carriage road through the village streets of the city or to visit old friends. Trace the past, we have no way of knowing who invented the wheel first child, who has created the first one wheeled vehicles. Although the wheel technology in the early and less than ideal, but it's there or to improve the human handling of goods, promoting human development. 2000 BC, some tribes began to Malays pull a wheeled vehicle, the wheels have started like this round, rather than early, as the whole wheel made of wood blocks. 1st century BC, the Roman system, Cartwright invented the chariot and gradually be improved, making the four-wheel carriage can be driven forward. In order for carriage of higher performance, they are embedded in Phnom Penh on wheels used to reduce the friction wheel and body. After such a long-distance transport of horse-drawn vehicles for a major national transport vehicles. The advantage is that transport large and smooth operation, drawback is the need to travel relatively flat road. With the road for carriage driving dilapidated, two-wheelers people and use practical, because it can travel over rough terrain can be. Later, after once again improved, but it is the speed of the carriage is not always satisfactory, hoping to invent a more endurance than the horse power and more robust machines to make the wheels to turn faster.
Thousands of years later, in some parts of the United Kingdom and the United States, few people began to experiment with steam-powered, with a steel-made road. This steam train will be there, its use greatly reduces the distance people travel time. However, because of restrictions on the laying of tracks, most places only people to rely on the carriage. To solve this problem, to find a way to completely replace the carriage of goods, inventors began to busy again. Later, through unremitting efforts, Carl ? Benz developed a way to replace the carriage, is made of three cars of steel. Benz invented the three-wheeled vehicles loading only the equivalent of two carriages, the carriages are not comfortable shelter for passengers, can not get you recognized. Sooner or later gold will be shining, and soon was on the three vehicles has been transformed, it becomes four wheels, and has the same belt as the carriage window boxes, it also has a nice name, "No Mama car."
In this four-wheeled vehicles appears, with the biggest wagon is a different place when cornering. When the carriage is in turn control the horse drag to change the forward direction of the front two wheels, then connected with the two front wheels for steering the rear trunk drag movement. As the horse is a source of power, front wheel only to be dragged to complete turn of the horse, rear-wheel drive through the body done, so there is no turning difficult problems. The car's structure is completely different, it will be the engine installed in the car body, but the forces driving the car forward, but must be sent directly to the wheels. Power transfer to go through the clutch, transmission, universal joints, drive shafts and other devices. This car's front and rear wheels out more between a lever, while the lever can only be passed back to a speed of two wheels, so a direct consequence of the rear wheels can rotate at different speeds, will result in turning difficult.
If the car turns smoothly, the two rear wheels can not turn the same speed. When the car turns, the wheel travel path is an arc, if turning left, the center of the arc on the left, at the same time, the right wheels to go a long arc than the left wheel. When the car turns left and right wheels to balance the difference the right wheels turn a little faster, turn the wheel left a little slower, with different speed to compensate for the distance differences.
Automotive engineers to solve this problem. First they try to make the two rear wheels are no longer using a lever connected but disconnected, so that the two rear wheels with a lever alone, that is, two independent axes, is the axle. As long as the lever on the axle of the two were subject to different forces, we can make about two wheels have different speeds. After the trouble came off, the car is only a drive shaft, how can two axle, respectively, to transmit power it reasonable? This requires a device to do the middle of "person." First with two levers and two connections in the vertical angle of the lever connected to the rear, and then by a lever in a horizontal position and vertical position of the two levers intersect, so as to drive two rear wheels turn. Although such a connection can be made for the two rear wheels rotating, but can not achieve the two wheels rotate at different speeds, because their actual sense, or as a whole. After years of experiments found that the lever connecting the two rear wheels of the installation of a cross on the lever, and with them also installed a vertical angle of the same cross levers, and use this leverage to drive two wheels cross the cross on the lever. With the vertical angle of the cross lever rotation in the middle of the cross lever and not at the same time connecting the two rear wheels driven by the cross levers, wheels in order to achieve the two different speeds.
Although this can solve the problem of two different speed rear wheel, but the space is too large cross levers, three cross drive lever prone to difficult situations. Then on the basis of the cross lever to add more leverage, increased to a total of twelve, to form a three twelve leverage wind wheel, so all three can be a good wind wheels turning. Solution model has manufactured, the total can not be directly installed in the car on it. With the wind in the mechanical function of the wheel is the same gear, and gear as needed to create more teeth to bite, life is relatively long, there is minimal chance of loss is completely the best choice to achieve this model.
This design was simply to complete the original program does not actually applied to the car. Like any masterpiece needs a finishing touch to complete this amount of people is the founder of France, Louis Renault ? Renault. Renault saw the original design, in order to apply it to the car If we need to improve Caixing. Closely not only need to gear meshing, gear may also need to rotate together with the other gear, but gear can not be too much, six is ??enough. What is there, or should give it a nice name, "differential" pretty good, and vivid image.
In this way, to solve the problem of differential turning car was born. Over the next 100 years, other components for automotive appearance and generation after generation, but the key components is not much change, because it's composed of the principle that it is destined that way. Look like? Simple point that is formed by the six gears. Complex that is formed by a group of planetary gears, two core and two planetary gear shaft with the left rear wheel axle gear connected. What is a planetary gear? In the vast universe, there is such a planet, it is not only revolve around their own axis of rotation, but also around other planets to rotate. Such as the Earth, the Earth is a planet. Not only to rotation, but also around the sun to keep the revolution. Understand what is a planet, the planetary gear up it is easy to understand. Planetary gear means to turn that not only their own, but also around the other gears of the gear. Differential is composed of six gears, planetary gear + two = four gear two axle gear, there are two. The remaining two gears with the drive rod is responsible for connecting the engine output power, gearbox and drive shaft after a smooth transition to the differential, then the differential will be based on the actual situation to the power distribution left and right rear wheels. Only differential installed in the rear axle drive rod between the two can achieve reasonable control wheel speed, in order to achieve the speed of two wheels with different purposes. In this six gear installed to the appropriate location, can not let them exposed it, still need a safe shelter to protect shell to protect the gear position is not affected by other parts of the interference. To save space, modern differential rarely use the classic flat gear, and more is to use the song bevel gears, screw gears, hypoid gears or worm, but the basic structure of the six gears have been continued down.
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