536 液壓機械傳動開式試驗臺設(shè)計（有cad原圖+文獻翻譯）,536,液壓機械傳動開式試驗臺設(shè)計（有cad原圖+文獻翻譯）,液壓,機械傳動,試驗臺,設(shè)計,cad,原圖,文獻,翻譯 DIFFERENTIAL AND REAR AXLES The differential is part of the rear-axle-housing assembly,which includes the differential,rear axles,wheels,and bearing. If the car were to be driven in a straight line without having to make turns,then no differential would be necessary.However,when the car rounds a turn,the outer wheel must travel farther than the inner wheel.The differential permits the two rear wheels to rotate different amounts when the car goes around a turn , while still delivering power to both rear wheels. The rear axles are attached to the wheels and have bevel side gears on their inner ends.The differential case is assembled on the left axle but can rotate on a bearing independently of the axle.The differential case supports the differential-pinion gear on a shaft,and this gear meshes with the two bevel gears.The fing gear is attached to the differential case so that the case rotates with the fing gear when the latter is driven by the drive pinion. The driving power enters the differential through the drive pinion on the end of the propeller shaft.The drive pinion is meshed with a large ring gear so that the ring gear revoves with the pinion. Attached to the ring gear is a differential-pinion shaft on which are assembled two differential-pinion gears.Each rear car wheel has a separate axle, and there are two side gears splined to the inner ends of the two wheel axles.The two side gears.When the car is on a straighet road ,the two differential-pinion gears do not rotate on the pinion shaft ,but they do exert pressure on the two side gears turn at the same speed as the ring gear ,causing both rear wheels to turn at the same speed,also. When the car rounds a curve ,the outer wheel must turn faster than the inner wheel,To permit this,the two pinino gears rotate on their pinion shaft,transmitting more turning movement to the outer side gear that to the inner side gear.Thus,the side gear on the outer-wheel axle turns more rapidly than the side gear on the inner wheel axle.This permits the outer wheel to turn more rapidly while the car is rounding the curve. There are two basic types of axle:deed axles and live axle.The dead axle does not rotate; the wheel rotates on it.A common exmple is the axle on a horse-drawn wagon.Live axles are attached to the wheel so that both the wheel and the axle rotate together.Live axles are classified according to the manner in which they are supported:semifloating, three-quarer-floating,and full-floating. AUTOMOBILE SYSTEM The fuel system has the job of supplying a combustible mixture of air and fuel to the engine. The fuel system must vary the proportions of air and fuel to suit different operating conditions. When the engine is cold, for example, then the mixture must be rich（have a high proportion of fuel）.The reason for this is that the fuel does not vaporize rapidly at low temperatures. Therefore, extra fuel must be added to the mixture so that there will be enough vaporized fuel to form a combustible mixture. The fuel system consists of the fuel tank, fuel pump, fuel filter, carburetor, intake manifold, and fuel lines, or tubes, connecting the tank, pump, and carburetor. Some gasoline engines use a fuel-injection system; in this system, a fuel-injection pump replaces the carburetor. The fuel tank, in which gasoline is stored, is normally located at the rear of the vehicle. It is made of sheet metal and is attached to the frame. A fuel pump delivers fuel from the tank to the carburetor. There are two general types of fuel pump, mechanical and electric. The fuel system has filters and prevent dire in the fuel from entering the fuel pump or carburetor. Dirt could, of course, prevent normal operation of these units and cause poor engine performance. The carburetor is essentially a mixing device which mixes liquid gasoline with air. In this process, it throws a fine spray of gasoline into air passing through the carburetor on its way to the engine. The gasoline vaporizes and mixes with the air to form a highly combustion chambers, where it is ignited. It burns, causing the engine to produce power. The mixture must be of varying degrees of rich nice to suit engine operating conditions. It must be rich（have a higher percentage of fuel）for starting, acceleration, and high-speed operation. And it should lean to（become less rich）for operation at intermediate speed with a worm engine. The carburetor has several different circuits, or passages, through which fuel and air-fuel mixture flow under different operating conditions to produce the varying richness of the air-fuel mixture. The purpose of the cooling system is to keep the engine at its most efficient operating temperature at all engine speeds and all drilling conditions. A great deal of heat is produced in the engine by the burning of the air-fuel mixture. Some of this heat escapes from the engine through the exhaust gases（the hot gases left after the gasoline is burned）. But enough remains in the engine to cause serious trouble unless removed by some other means. The cooling system takes care of this additional heat. The cooling system is built into the engine. There are hollow spaces around each engine cylinder and combustion chamber. These hollow spaces are called waterjackets, since they are filled with water. When the engine is running, the water takes heat from the engine, becoming hot in the process. A water pump pumps the hot water from the engine water jackets into the radiator. The radiator has two sets of passages. One set carries air（pulled through by car motion and the engine fan）. As the hot water passes through, it gives up its heat to the air passing through. The cooled water then reenters the engine, where it can pick up more heat. In operation, water continuously circulates between the engine and radiator, carrying heat from the engine temperatures are prevented. Two general types of cooling systems are used, air cooling and liquid cooling. The liquid cooling system consists of water pumps, water jackets, engine fan, radiator and so on. The water pump, driven by a belt from the engine crankshaft, circulates the cooling liquid between the radiator and engine water jackets. The cooling liquid is water. Antifreeze compounds are added to the water during the winter. The water jacket are cast into the cylinder blocks and heats. The engine fan is usually mounted on the water-pump shaft and is driven by the same belt that drives the pump shaft and the generator. The purpose of the fan is to provide a powerful draft of air through the radiator. The radiator is a device for holding a large volume of air so that heat will transfer from the water to the air. The radiator core is divided into two separate compartments; water passes through one, and air passes through the other. The ignition system is part of the electric system of the automobile. Its purpose is to produce high-voltage surges（up to 20 000 volts）and to deliver them to the combustion chambers in the engine. These high-voltage surge surges then cause electric sparks in the combustion chambers. The sparks ignite, or set fire to, the air-fuel mixture in the combustion chambers so that it burns and cause the engine ton operate. The ignition system consists three basic parts: the ignition distributor, the ignition coil, and the spark plug, together with the connecting wires. When the engine is running, the ignition coil is repeatedly connected, it becomes loaded with electrical energy. Then, when it is disconnected, the “l(fā)oad” of electrical energy is released in a high-voltage. This surge flows through the wiring to the spark plug in the engine cylinder that is ready to fire. You must understand that all this takes place very rapidly. At high speed, the whole series of events happens in less than one three-hundredth of a second. That is, there will be as many as 300 of these events every second that the engine is running at high speed. Some systems use transistors to reduce the load on the distributor contract points. Other systems do not have contract points use instead a combination of transistors and a magnetic pick-up in the distributor. The ignition distributor has two jobs. First, it closes and opens the circuit between the battery and the ignition coil. The distributors second job is to distribute each high-voltage surge to the correct spark plug at the correct instant by means of the distributor rotor and cap and secondary wiring. There are two basic types of distributor: （1）the type using contact points to close and open the coil primary circuit; （2）the type using a magnetic pick-up and a transistor control unit to interrupt the current flow of the coil primary circuit. Automobile engines are not self-starts. In order to start them, the engine crankshaft must be turned over by some outside means so as to（a）admit air-fuel mixture to the cylinder, and（b）cause the mixture to fire. In the case of automobile engines, the mixture in the cylinder, after being compressed, must be not enough to ignite. This requires that the engine be turned over with sufficient speed. If the engine is turned over too slowly, the unavoidable small leaks past the piston rings and also through the intake and exhaust valves of four-circle engines will permit a substantial part of the fuel-air mixture to escape during the compression stroke. Also, the heat loss from the compressed air to the cylinder walls will be greater at low speed because of the longer exposure. The escape of air and the loss of heat both result in a lower temperature at the end of compression. Therefore, there is a minimum speed which the engine must attain before ignition will occur and the engine will begin firing. The starting speed depends upon the type and size of the engine, its condition, and the temperature of the air entering engine. The starting system contains a cranking, or starting, motor and other accessories. The starting motor electrically cranks the engine for starting. It is a special direct-current motor operating on battery voltage and is mounted on the engine flywheel house. The starter changes the electrical current into the mechanical energy to push the crank-shaft round. By means of this, the engine can be started. The cranking motor consists of the commutator end head, holding the brushes; the field frame, into which the field windings are assembled around pole shoes; the drive housing, which house the drive assembly and supports the motor on the engine flywheel housing; the armature; and the drive assembly. Some cranking motors also have a solenoid that operates the shift lever. Cranking-motor controls have varied from a simple foot-operated pedal to automatic devices that close the cranking-motor circuit when the accelerator pedal is depressed. The present system that has been almost universally adopted for passenger cars and many other vehicles has starting contacts in the ignition switch. When the ignition key is turned against spring pressure past the ON position to START, the starting contacts close. This connects the cranking-motor solenoid or magnetic switch to the battery. After the engine starts and the ignition key is released, spring pressure returns it to the ON position. The starting motor should not be operated more than 5 seconds during each starting operating, for the sake of recovering the energy of battery. It will not be allowed to start it again until its stopped for fifteen seconds. The manual transmission shown in Fig.—1 provides a means of varying the relationship between the speed of the engine and the speed of the wheels .Varying these gear ratios allows the right amount of engine power at many different speeds. Manual transmission requires use of a clutch to apply and remove the torque to the transmission input shaft. The clutch allows this to happen gradually a so that the car can be started from a complete stop. Modern manual transmissions do not disengage any of the forward drive gears, they are simply connected to their shafts through the use of “synchronizers”.Reverse is achieved reverse idler gears ,which are engaged to move the car backwards. Some manual transmissions have an “overdrive”. An overdrive is a mechanical unit bolted to rear of the transmission. It is usually known as the fifth gear .When you use it, it will reduce the engine speed by about one-third ,which maintaining the same road speed. In an automatic transmission, gear ratios are changed automatically. This eliminates the need for the driver to operate the clutch and manually “shift gears.” The typical automatic transmission combines a fluid torque converter , a planetary-gear system, and a hydraulic control system in a single unit. As car speed changes , various gear ratios between the crankshaft and the wheels are selected and then changed automatically. Automatic controls inside the transmission supply the proper ratio for the driving condition. In addition to the forward-gear ratios, neutral, and reverse, the automatic transmission has a PAPK position. This locks the transmission to prevent the car from moving or rolling away while parked. 差速器和車橋 差速器和后橋殼總成的一個部件，后橋殼總成包括差速器、后橋、車輪和軸承。 如果汽車按直線行駛，就不需要差速器了。然而，當汽車轉(zhuǎn)彎時，外測的車輪一定比內(nèi)測的車輪行駛更長的距離。差速器可在汽車轉(zhuǎn)彎時使兩個后車輪以不同的轉(zhuǎn)速轉(zhuǎn)動，同時還向兩個后輪提供動力。 后橋與車輪相連，內(nèi)端裝有一個半軸齒輪。差速器殼支承在左側(cè)車橋上，而且能夠在軸承上做獨立轉(zhuǎn)動。差速器殼支承在行星齒輪軸上，行星齒輪與兩個半軸齒輪相嚙合。冠狀齒輪與差速器殼相連，這樣當冠狀齒輪由傳動齒輪驅(qū)動轉(zhuǎn)動時，差速器殼也在轉(zhuǎn)動。 也就是說，驅(qū)動力是從傳動軸末端的傳動齒輪輸送到差速器的。傳動齒輪與一個很大的冠狀齒輪嚙合，傳動齒輪驅(qū)動冠狀齒輪。 冠狀齒輪與差速器齒輪軸相連，差速器齒輪軸上裝有兩個行星齒輪。每個后車輪都有一個獨立的車橋，兩個半軸齒輪用花鍵與兩個車軸的內(nèi)端相連。兩個行星齒輪與這兩個齒輪相嚙合。當汽車直駛時，兩個行星齒輪不在齒輪軸上轉(zhuǎn)動，但卻向兩個半軸齒輪傳遞動力，這樣半軸齒輪與冠狀齒輪的轉(zhuǎn)速相等，從而使兩個后輪也以同樣的速度轉(zhuǎn)動。 當汽車轉(zhuǎn)彎時，外測車輪就必須比內(nèi)側(cè)車輪轉(zhuǎn)的更快。為了達到這一目的，兩個行星齒輪在齒輪軸上轉(zhuǎn)動，給外側(cè)的車輪提供比內(nèi)側(cè)的車輪更多的運動，這樣外側(cè)車輪軸上的半軸齒輪比內(nèi)側(cè)車輪軸上的半軸齒輪轉(zhuǎn)動更快，這樣，當汽車轉(zhuǎn)彎時，外側(cè)車輪就轉(zhuǎn)的更快些。 車橋有兩種基本形式：非斷開式和斷開式。非斷開式車橋不轉(zhuǎn)動，而車輪在車橋上轉(zhuǎn)動。最常見的例子就是在馬車上所見到的非斷開式車橋，斷開式車橋與車輪相連，這樣兩者一起轉(zhuǎn)動。斷開式車橋根據(jù)其承載可分為：半浮動，四分之三浮動和全浮動。 汽車系統(tǒng) 發(fā)動機的燃油系統(tǒng)： 燃料供給系統(tǒng)的作用是向發(fā)動機提供由空氣和燃料所組成的可燃混合氣。燃料系統(tǒng)必須改變空氣和燃料的比例以適應(yīng)不同的運行狀態(tài)。例如，當發(fā)動機冷車時，就必須提供較濃的混和氣（具有較高的燃油比例）。這是因為在低溫下燃油不能迅速汽化，因此，要在混合氣中額外增加燃油，這樣才有足夠汽化燃料形成可燃混合氣。 燃料系包括汽油箱、汽油泵、汽油濾清器、化油器、進氣歧管以及連接油箱、油泵和化油器的油管。有的汽油發(fā)動機使用的是一套燃油噴射系統(tǒng)，在這一系統(tǒng)中，燃油噴射泵取代了化油器。 汽油箱用來儲存汽油，通常安裝在汽車的后部。油箱由金屬板制成，固定在車架上。 油泵把油箱的燃油抽出送到化油器中。通用的油泵有兩種:機械泵和電子泵。燃油系統(tǒng)裝有濾清器和過濾網(wǎng)，防止燃油的雜物進入燃油泵和化油器。否則，污物會影響這些部件的正常運轉(zhuǎn)，并引起發(fā)動機運轉(zhuǎn)不良。 化油器實際上是一個把液體燃油與空氣相混合的混合氣形成裝置。在這一過程中，化油器把燃油以霧狀噴入流經(jīng)化油器得空氣中，然后進入發(fā)動機。霧化燃油和空氣形成高度易燃的混合氣?？扇蓟旌蠚膺M入發(fā)動機的燃燒室，并在那里被點燃。可燃混合氣燃燒，使發(fā)動機產(chǎn)生動力?；旌蠚獾臐舛缺壤梢愿淖儯赃m應(yīng)發(fā)動機的運行狀況。汽車在啟動、加速和高速行駛時，需要含油濃度較高的混合氣；熱狀態(tài)下的發(fā)動機中速行駛時，混合氣含燃油濃度則可低一些?；推饔袔讉€不同的供油系統(tǒng)和通道，通過這些供油系統(tǒng)，再不同的行駛狀態(tài)下，可提供不同的可燃混合氣。 發(fā)動機冷卻系統(tǒng)： 冷卻系統(tǒng)的作用是控制發(fā)動機在各種轉(zhuǎn)速和各種行駛狀態(tài)下都能有效的控制溫度。 混合氣的燃燒在發(fā)動機中產(chǎn)生大量的熱，其中部分熱量通過廢氣排除。是，殘留在發(fā)動機中的余熱仍足以使發(fā)動機受到嚴重損壞，除非用其他方法排除這些余熱，冷卻系統(tǒng)就是專門消除這些余熱的。 冷卻系統(tǒng)就設(shè)置在發(fā)動機中。在每個氣缸體和燃燒室周圍都留有空腔。這些空腔裝滿了水，因此稱之為水套。在發(fā)動機的運行過程中帶走。水泵從發(fā)動機水套中把熱水抽到散熱器中。散熱器有兩條通道：一條是水道，另一條是氣道。當熱水流過水道時，氣道中流通的空氣使熱水冷卻。冷卻后的水又重新進入發(fā)動機，再把發(fā)動機的熱量傳導(dǎo)過去。在這一過程中，水不斷地在發(fā)動機與散熱器之間循環(huán)，水攜帶著熱量從發(fā)動機流到散熱器再散發(fā)出去。通過這個辦法可以避免發(fā)動機過熱。 通常使用的冷卻系統(tǒng)有兩種形式：空氣冷卻和液體冷卻系。現(xiàn)在大多數(shù)發(fā)動機都采用液體冷卻系。液體冷卻系由水泵、水套、發(fā)動機風扇、散熱器等組成。水泵由發(fā)動機曲軸上的皮帶驅(qū)動，使冷卻液在散熱器與發(fā)動機水套之間循環(huán)流動。冷卻液是水。冬季在水中必須加入防凍劑。水道被鑄入氣缸體內(nèi)部。發(fā)動機風扇通常安裝在水泵軸上，由驅(qū)動水泵和發(fā)電機的同一條皮帶驅(qū)動。風扇的作用是向散熱器提供強大的空氣流，與大量空氣密切接觸的散熱器內(nèi)可以容納大量的水，這樣的熱量可以通過水散發(fā)到空氣中。散熱器芯為分離和間隔交錯的兩部分。冷卻水在其中一部分中流過，空氣在另一部分中通過。 發(fā)動機點火系統(tǒng)： 點火系統(tǒng)是汽車電氣系統(tǒng)的一部分。其作用是產(chǎn)生高達2萬伏的高壓電脈沖，并且將其輸送到發(fā)動機的燃燒室。高壓電脈沖在燃燒室形成電火花，引燃燃燒室中的可燃混合氣，使發(fā)動機運轉(zhuǎn)。 點火系統(tǒng)包括三個基本部分：點火分電器、點火線圈和火花塞，以及起連接作用的導(dǎo)線。當發(fā)動機轉(zhuǎn)動時，點火線圈和蓄電池之間不斷地連接和斷開。每當線圈與蓄電池 接通時就會充載電荷，然而當線圈與蓄電池斷開時，電荷以高壓脈沖的方式釋放出來，通過導(dǎo)線把高壓電脈沖輸送大待點火的發(fā)動機氣缸的火花塞上。你必須理解這一切發(fā)生在短短的三百分之一秒內(nèi)。也就是說，在發(fā)動機高速運轉(zhuǎn)時，這樣的動作每秒鐘就要發(fā)生三百次。 有些點火系統(tǒng)使用晶體管來減少分電器觸點，而是在分電器與磁傳感器。點火系統(tǒng)的分電器有兩個作用。首先，負責接通知和關(guān)閉蓄電池和點火圈之間的電路。分電器的第二個作用是通過分火頭、旁電極和輔助線路，將高壓電流準時地分配給相應(yīng)的火花塞。 分電器有兩種基本形式：一種是使用觸點關(guān)閉和接通出級線圈的電流，另一種使用磁傳感器和晶體管控制裝置來切斷初級線圈的電流 發(fā)動機啟動系統(tǒng)： 汽車發(fā)動機是發(fā)動機不能自行啟動的。為了啟動發(fā)動機，發(fā)動機曲軸必須借助外界的手段轉(zhuǎn)動起來，這樣：使可燃混合氣進入氣缸；使可燃混合氣點火。對于汽車發(fā)動機來說，氣缸中的可燃混合氣被壓縮后，必須有足夠的熱量才能被點燃。這就要求發(fā)動機達到足夠高的轉(zhuǎn)速。如果發(fā)動機 轉(zhuǎn)速太慢，四行程發(fā)動機的活塞環(huán)和進排氣門就不可能避免地有泄露現(xiàn)象。這會使大量的可燃混合氣在壓縮行程期間泄漏掉。此外，發(fā)動機在低速時，由于接觸時間較長，壓縮氣體傳給氣缸壁的熱量較大。在壓縮過程結(jié)束，溫度較低的情況下，會產(chǎn)生漏氣和熱損失兩種現(xiàn)象。所以，發(fā)動機在引燃和開始點火前，必須達到一個最低轉(zhuǎn)速。啟動轉(zhuǎn)速取決于發(fā)動機型號、大小和狀態(tài)以及進入發(fā)動機的空氣的溫度。 啟動電機用電能來啟動發(fā)動機。啟動機是以蓄電池為動力來源的直流電機，它安裝在發(fā)動機的飛輪殼上。啟動電機把電流轉(zhuǎn)換為機械能，驅(qū)動曲軸轉(zhuǎn)動，并帶動發(fā)動機運轉(zhuǎn)。啟動電機由固定電刷的換向器頭、磁場匡架、傳動箱、電樞以及傳動總成等組成，在磁場匡架中，勵磁線圈內(nèi)套著電樞；傳動箱內(nèi)裝有傳動總成，并且支撐固定在發(fā)動機飛輪殼上的電機。有些啟動電機還有一線圈來帶動操縱桿。 控制啟動機的方式已從一個簡單的腳踏板改為壓下加速踏板即可自動接通啟動機電路的自動裝置。 許多其他類型的車量已普遍采用開關(guān)裝置。啟動接觸器裝在點火開關(guān)上。轉(zhuǎn)動點火鑰匙，彈簧的壓力使“開啟”位置變?yōu)椤皢印蔽恢茫瑔咏佑|器閉合，使得啟動電機線圈或詞性開關(guān)與電池接通。發(fā)動機啟動以后，點火鑰匙回轉(zhuǎn)，在彈簧壓力下，恢復(fù)到“開啟”位置。啟動電機每次啟動過程的時間限定在5秒內(nèi)，以便是電池的能量及時得到補充。15秒后方可再次啟動。