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畢業(yè)設(shè)計外文資料翻譯
設(shè)計題目: JD1121載貨汽車總體及底盤布置設(shè)計
譯文題目: 汽車底盤構(gòu)造
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正文：（汽車底盤）
汽車底盤構(gòu)造
汽車型號的不同使汽車的設(shè)計也有所不同，一輛私家車可以承載人數(shù)的上限是八個人，一般需要四個座位。
汽車設(shè)計的布局如圖1-1所示，它體現(xiàn)了這輛汽車各個主要部件的布置，它是由位于汽車前邊的發(fā)動機、接著是離合器、變速器、傳動軸、萬向節(jié)、差速器、后橋等部件布置構(gòu)成。汽車散熱器位于汽車發(fā)動機的前邊，圖中其他的各種不同的汽車零件則分別是發(fā)電機、喇叭、轉(zhuǎn)向機、風(fēng)扇、正時齒輪、化油器、空氣濾清器、齒輪傳動控制裝置、方向盤、汽缸、汽油油槽、后橋主動及被動齒輪、后車橋。驅(qū)動力由變速器輸出，通過一個短軸輸送到到前邊傳動軸的萬向節(jié)上，再從傳動軸輸出，經(jīng)過一個接頭形式的、可滑動花鍵輸送到傳動軸后部，然后帶動傳動軸軸上的錐齒輪，這個錐齒輪再與一個大的錐齒輪相嚙合，這個大的錐齒輪經(jīng)過一個差速齒輪驅(qū)動著后橋的半軸。
圖1-1 車的總布置
1-車架 ; 2-車輪 ; 3-散熱器 ; 4-發(fā)動機 ; 5-離合器和變速器; 6-傳動軸 ; 7-萬向節(jié) ; 8-差速器, 后橋 ; 9-油箱;10-前橋 ; 11-轉(zhuǎn)向器; 12- 鋼板彈簧 ; 13-排氣管/消音器
這個總布置設(shè)計同時還包括獨立的1/4橢圓的樹業(yè)形狀的獨立懸架系統(tǒng)的設(shè)計，還包括轉(zhuǎn)向桿的錐齒輪控制系統(tǒng)和液力制動系統(tǒng).
能量的單元是由發(fā)動機構(gòu)成的，他通常安裝在車底盤的較低點。離合器以及變速器安置在它之后，這三個部分,發(fā)動機,離合器和變速器組裝成一個獨立的單位。
底盤
汽車底盤是指對汽車底部所有結(jié)構(gòu)的描述?，F(xiàn)代汽車的主要結(jié)構(gòu)就是底盤結(jié)構(gòu)。大量的設(shè)計要求是在發(fā)動機，輪胎，車軸組件，變速器，轉(zhuǎn)向機構(gòu)，制動器和懸架安裝在鋼制框架上。在底盤的制造過程中主要取決于螺栓的靈活性。底盤基本框架的主要組成部分是，發(fā)動機，動力傳動系統(tǒng)，輪胎，轉(zhuǎn)向裝置，制動器，懸架和汽車轉(zhuǎn)向所需要的所有部件。此外，其他幾個系統(tǒng)是也被安裝在底盤上。懸架系統(tǒng)無論是對穿越崎嶇道路的旅行車輛輪胎還是對在正確公路上行駛的汽車輪胎都有吸收道路沖擊的作用。當(dāng)馬路不平引起汽車顛簸時，它也能允許輪胎上下移動。
另一個重要的底盤部分是轉(zhuǎn)向系統(tǒng)，它是駕駛員用來控制汽車行駛方向的系統(tǒng)。駕駛員控制的方向盤被連接在變速器上，使駕駛員的控制力變強。這個變速器是被連接到車輛的前輪上。
汽車底盤的另一個主要組成部分是制動系統(tǒng)，它的作用是能使行駛車輛減速，使車輛停止，如果車輛已停止將保持平穩(wěn)狀態(tài)。當(dāng)駕駛員踩動剎車踏板時，液壓油被迫離開主缸傳到四個輪子中，由液壓運動產(chǎn)生的鼓狀和盤式制動器作用使汽車的輪胎放慢或停止。
發(fā)動機
柴油發(fā)動機效率比汽油發(fā)動機的高35%-40% ，生產(chǎn)更多的電力單位燃料的燃燒。 The efficiency of the diesel engine has been greatly enhanced by the use of turbochargers and charged-air cooling, which has resulted in increased power and performance at minimum fuel consumption rates.效率的柴油發(fā)動機已大大加強，使用渦輪增壓器和帶電空氣冷卻，從而導(dǎo)致更多的功率和性能，最低燃油消耗率。 Advancements in engine design also mean diesel is no longer considered a "dirty" fuel.先進的發(fā)動機設(shè)計也意味著柴油已不再被視為“骯臟”的燃料。 Fuel injection and control strategies have produced the "smokeless" diesel.燃油噴射和控制戰(zhàn)略已產(chǎn)生的“無煙”柴油。發(fā)動機的作用是使輸入汽缸的燃料燃燒而發(fā)出動力。現(xiàn)代汽車廣泛應(yīng)用往復(fù)活塞式內(nèi)燃機，它一般有機體，配氣機構(gòu)，曲柄連桿機構(gòu)，燃油供油系統(tǒng)，冷卻系統(tǒng)，點火系統(tǒng)，啟動系統(tǒng)等部分組成。地盤接受發(fā)動機的動力，使汽車產(chǎn)生運動，并保證汽車按照駕駛員的操縱正常行駛。
離合器
離合器的主要功用是切斷和實現(xiàn)發(fā)動機對傳動系的動力傳遞，保證汽車起步時使發(fā)動機和傳動系平順的接合，確保汽車平穩(wěn)起步；在換擋時將發(fā)動機和傳動系分離，減少變速器中換擋齒輪之間的沖擊；在工作中受到較大的動載荷時，能限制傳動系所承受的最大轉(zhuǎn)矩，以防止傳動系各部分零件因過載而損壞；有效地降低傳動系中的振動和噪音。
變速器
變速器是一個速力變化裝置,安裝在車輛的發(fā)動機和驅(qū)動輪之間.變速器用以改變發(fā)動機與驅(qū)動輪轉(zhuǎn)速間的比率關(guān)系.以適應(yīng)每種行駛狀況. 傳輸裝置連接到背面的發(fā)動機發(fā)出的功率,從發(fā)動機驅(qū)動車輪. 這樣在一定的范圍內(nèi)汽車發(fā)動機的運行也會處于最佳狀態(tài)。
前橋
前橋是用來控制與固定在車橋兩端上的部件并通過相互連接的在前車橋末端的轉(zhuǎn)向節(jié)上進行轉(zhuǎn)動。為減輕整車的質(zhì)量,讓整車結(jié)構(gòu)更緊湊,采用膜片彈簧離合器,高速旋轉(zhuǎn)時其性能 穩(wěn)定，膜片彈簧離合器與螺旋彈簧離合器相比有以下優(yōu)點,傳遞的轉(zhuǎn)矩較大而且平穩(wěn)，結(jié)構(gòu)簡單緊湊，操縱輕便,使用壽命長。
轉(zhuǎn)向器
轉(zhuǎn)向器以及轉(zhuǎn)向拉桿將兩根轉(zhuǎn)向軸連接起來并通過與轉(zhuǎn)向節(jié)相連的轉(zhuǎn)向盤轉(zhuǎn)向輪來轉(zhuǎn)動他們，轉(zhuǎn)向盤通過一根軸連接到了轉(zhuǎn)向搖臂的一端，變速器以及一個合適的連接軸通過駕駛員的操作而被執(zhí)行。先前的單個橋是通過彈簧來支持汽車，在這里的布置還了解到采用獨立前懸已經(jīng)取代了車軸和彈簧的所一起布置形成的系統(tǒng)。在采用獨立懸架內(nèi)彈簧的控制下，車輪就可以獨立于其他自由的上下彈動了。
驅(qū)動橋
為了安裝好后邊的車輪，用半軸套管將半軸在輪子被使用的時候開始通過合適的軸承來驅(qū)動后橋，在發(fā)動機和兩個驅(qū)動車輪之間，為了促使驅(qū)動橋內(nèi)的驅(qū)動齒輪提供最終轉(zhuǎn)速，它在驅(qū)動橋中心的轉(zhuǎn)速不斷增大，這種方向改變的驅(qū)動放把前部和后部到排列成一條直線的傳動軸的軸槽也是由這種部件提供的，它被稱為后置驅(qū)動橋.
差速器就是一種將發(fā)動機輸出扭矩一分為二的裝置，允許轉(zhuǎn)向時輸出兩種不同的轉(zhuǎn)速。在現(xiàn)代轎車，包括許多四輪驅(qū)動汽車上，都能找到差速器。這些四輪驅(qū)動車的每組車輪之間都需要差速器。同樣，其兩前輪和兩后輪之間也需要一個差速器。這是因為在汽車轉(zhuǎn)彎時，前輪和后輪對比后輪，走過的距離是不相同的。 部分四輪驅(qū)動車前后輪之間沒有差速器。相反的，他們被固定聯(lián)結(jié)在一起，以至于前后輪轉(zhuǎn)向時能夠以同樣的平均轉(zhuǎn)速轉(zhuǎn)動。
每個車輪都設(shè)有自己單獨的半軸，通過差速器的差速齒輪連接到一起并在驅(qū)動橋的中心匯合，車輪都可以以不同的速度自由轉(zhuǎn)動，雖然他們都靠不同的齒輪提供同樣的驅(qū)動.
制動器
控制或者阻止汽車運動，高效率的制動系統(tǒng)是汽車所不可缺少的，通過四個車輪起到剎車作用的部件有兩種類型，最起初的類型，一對剎車片被固定在一個固定的板子上，被擴大然后連接到安裝在輪子上旋轉(zhuǎn)式的制動鼓上，這樣可以控制到鼓的執(zhí)行動作。在現(xiàn)代的剎車類型上，一對或者多對的墊片被放置在一個靠在車橋或者車輪支撐連接的卡鉗上，被安裝在輪胎上側(cè)面的制動盤以用來緊緊的抓住這些墊片，通過在踏板施加壓力來實現(xiàn)剎車。手動杠桿的作用是通過一個單獨的連接來鎖定定位器。
在制動器的操作方面，無論是機械式的制動系統(tǒng)還是液壓制動系統(tǒng)都可以被使用。機械式的制動系統(tǒng)需要通過機械傳動和流體液壓等過程進行液壓制動來進行應(yīng)用。
傳動軸和萬向節(jié)
讓變速器的輸出軸連接到后橋，這個被使用的長軸被稱之為傳動軸，這個傳動軸被一個管型套所密封或者被一個萬向節(jié)所打開并裝在每個萬向節(jié)的末端，以用來通過因地面不同的變化而導(dǎo)致的各種形狀的傳動軸的連接的上下變化。萬向節(jié)不能消除，即使有最終傳動齒輪是安裝在固定在車輪獨立懸架的彈簧的車架上。即可以避免因路上的顛簸未對準而導(dǎo)致的汽車構(gòu)造的變形，又可以保證沒有它們的時候軸的準確性。
為了阻止在不平坦的路面上產(chǎn)生的振動傳輸?shù)狡噧?nèi)部，這里在汽車的車橋上采用了彈簧用來支持汽車保證汽車行駛的平順性。
為了使垂直運動的車輪相對車架以及允許的部分軸在不同的角度進行運動,另外，越來越多的這樣布置已經(jīng)被應(yīng)用推廣。由驅(qū)動齒輪和差速器組成的一個系統(tǒng)在驅(qū)動橋殼軸管內(nèi)通過車輪上的獨立的并起彈簧作用的部件連接在車架上，這樣能把軸和部件連接在一起的裝置稱為萬向節(jié).
車輪
一共有四個輪子分別被安裝在汽車底盤的下面，用以承載汽車和乘客的重量，同時也能夠驅(qū)動汽車使汽車能夠行駛。他們與橡膠輪胎相適應(yīng)，橡膠輪胎中充滿了由橡膠管在一定壓力的有效壓力下充入的空氣，這個壓力對承擔(dān)負載是非常必要的，這樣來汽車輪胎內(nèi)有了足夠的壓力足以用于裝載運送東西，同時能夠承受吸收由于路面不平整而產(chǎn)生的顛簸。憑借安裝在輪子與車輛之間的鋼板彈簧以及允許做垂直上下顛簸運動的車輛，在大部分的不均勻路面將會得到較好的行駛條件。
當(dāng)按曲線行駛的時候，內(nèi)輪相對于外輪在轉(zhuǎn)彎的時候不得不行駛短一些的距離，但是后邊的兩個車輪當(dāng)他們連接到一個軸的時候?qū)⑥D(zhuǎn)動的速度將達到一致，通過兩個車輪一起旋轉(zhuǎn)通過在路面造成的輪胎過度磨損而將會導(dǎo)致其中的一個或兩個輪子將會在路面上慢慢滑動，并會導(dǎo)致額外的車輪磨損以及軸上嚴重的扭轉(zhuǎn)負荷。除此之外，兩個車輪的完全相同的直徑(即通常不是如此)能在同一個速度行駛的時候車輪沒有打滑在一條筆直的路上。輪胎安裝在兩個對立面,可能會產(chǎn)生不同位置的磨損,甚至輪胎是相同的直徑，但由不同或相同的制造商在實際尺寸上可能有所不同，或者未必完全相同。由于改變滾動半徑(距車輪中心與地面)的有效尺寸，輪胎將因為不同的膨脹壓力而改變大小。
汽車性能的優(yōu)劣不僅取決于組成汽車的各部件的性能，而且在很大程度上取決于各部件的協(xié)調(diào)和配合，取決于總體布置；總體設(shè)計水平的高低對汽車的設(shè)計質(zhì)量、使用性能和產(chǎn)品的生命力起決定性的影響。
Automobile chassis structure
The layout of different types of vehicles is different. A private car which is to carry upto eight persons is generally four seats.
The layout of a car is shown in (Figure1). It shows the position of the main parts of an automobile. It consists of engine located at the front of the vehicle, followed by a clutch, gear box, propeller shaft, universal joint, differential, back axle ect. The radiator is located in front of the engine. Various other parts of the vehicle shown in the layout are dynamo, horn, steering box, fan, timing gear, carburetor, air filter, gear control, steering wheel, cylinder, petrol tank, rear axle, back axle. The drive from the gear box is conveyed through a short shaft to the front universal joint of the propeller shaft.From the propeller shaft.it is conveyed to the rear universal joint through a sliding splined type of joint.The bevel gear of the short shaft is driven by the rear universal joint.This bevel gear meshes with a larger bevel gear which drives the tow rearaxle shafts through a differential gear.
Figure 1 layout of a car
1-Frame ; 2-Wheels ; 3-Radiator ; 4-Engine ; 5-Clutch and gearbox ；6-Propeller shaft ; 7-Uniwersal joint ; 8-Differential , Rear Axle ; 9-Fuel tank ;10-Front axle ; 11-Steering ; 12- Road springs ; 13-Exhaust/silencer
The layout also consists of independent front-wheel springing with quarter-elliptic leaf springs,steering column bevel-gear control and hvdraulic braking system.
Power unit consists of an internal combustion engine.It is usually mounted at the point end of the car.The clutch and the gear box are placed immediately behind it.The three components,engine,clutch and gear box are assembled into a single unit.
Chassis
The term chassis describes all the parts of the automobile under the body .The chassis forms the main structure of the modern automobile .A large number of designs in pressed-steel frame form a skeleton on which the engine ,wheels ,axle assemblies ,transmission ,steering mechanism ,brakes ,and suspension members are mounted .During the manufacturing process the body is flexibly bolted to the chassis . The major components of the basic chassis are the frame ,engine, drivetrain ,wheels ,tires ,steering , brakes ,suspension and steering-everything needed to drive the car .In addition, several other systems are mounted to the chassis assembly .The wheels of the automobile are connected to the frame t by a system of springs ,shock absorbers ,and linkages that make up the car’s suspension system .The suspension system absorbs road shocks as the vehicle travels over rough roads and holds the tire and wheel in correct alignment with the car and the road .It also allows the tires and wheels to move up and down relative to the body over bumps and chuckholes.
Another important chassis component is the steering system ,which allows the driver to control the direction the car travels. The steering wheel ,which the driver controls , is connected to a gearbox that multiplies the driver’s effort .The gearbox is linked to the front wheel of the vehicle.
The last major chassis component is the braking system the function ,the function of which is to either reduce the vehicle’s speed ,bring the vehicle to a halt ,or keep it stationary if already halted. When the driver pushes on the brake pedal,hydraulic fluid is forced out of a master cylinder to each of the four wheels .The resulting hydraulic pressure operates a drum or disk brake assembly to slow or stop the car’s wheels.
Engine
Diesel engines are substantially more efficient than gasoline engines by an estimate of 35-40 percent, producing more power per unit of fuel burned. The efficiency of the diesel engine has been greatly enhanced by the use of turbochargers and charged-air cooling, which has resulted in increased power and performance at minimum fuel consumption rates. Advancements in engine design also mean diesel is no longer considered a "dirty" fuel. Fuel injection and control strategies have produced the "smokeless" diesel. The role of the engine cylinder is to enable the importation of fuel combustion and a driving force. Hyundai Motor wider use of Reciprocating Engine, which generally organisms, with gas, crank linkage, fuel oil supply systems, cooling systems, ignition systems, launch systems and other components. Site to accept the engine driving force, so that a sports car, and to ensure that the driver of the vehicle in accordance with the manipulation of normal traffic.
Clutch
The main function of clutch is cut off and realize the transmission of engine power transmission to ensure that when the car started the engine and transmission smooth joint, to ensure a smooth start car in the shift when the engine and transmission of separation, to reduce transmission of the shift Gear between the impact in their work by the larger dynamic load, we can limit transmission of the largest faced by the torque to prevent the transmission of some parts due to the overload and damage to effectively reduce the transmission of noise and vibration .
Gear Box
A gear box is a speed and power changing device installed at some point between the engine and driving wheels of the vehicle.It provides a means for changing the ration between engine and driving wheels rpm to best meet each particular driving situation. The gear box is a device that is connected to the back of the engine and e same average speed. This is why these vehicles are hard to turn on concrete when the four-wheel-drive system is engaged.
Each wheel is sends the power from the engine to the drive wheels. An automobile engine runs at its best at a certain range.
Front Axle
Front axlw is used for steering front wheels carried on stubaxles swiveling upon king pins at the axle extremities.
Seering Systems
Steering arms and a track rod link the two stub axles together for swiveling them by a steering wheel about the king pins.The steering wheel linked to one of the stub axles by a shaft,a gear box and a suitable linkage is opeated by the driver’s hand wheel.Previously the axle-a onepiece beam was used to support the vehicle through springs,An arrangement known ad independent front suspension has replaced the axle and spring arrangement.Under the control of springs,the wheels are free to rise and fall vertically independently of each other.
Drive Axle
For fixing rear wheels,a tube like shaft enclosing driving shafts with suitable bearings for rotating the wheels is useds.It is enlarged at the center for enclosing the final drive gears used for providing main speed reduction between the engine and the driving wheels. The change of direction of the drive trom the fore and aft line of the propeller shaft to the transverse line of the axle shafts is also provided by this tube known as rear axle.
The differential is a device that splits the engine torque two ways, allowing each output to spin at a different speed. It is found on all modern cars, and also in many all-wheel-drive vehicles. These all-wheel-drive vehicles need a differential between each set of drive wheels, and they need one between the front and the back wheels as well, because the front wheels travel a different distance through a turn than the rear wheels. Part-time four-wheel-drive systems don't have a differential between the front and rear wheels; instead, they are locked together so that the front and rear wheels have to turn at thprovided with its own separate halfshaft connected by a differential gear and meeting at about the center of the axle.The wheels are free to rotate at different speeds although they are provided with equal by the differential gear.
Bake System
For controlling the movement of the vehicles or to stop them,efficient braking system is a necessity for a vehicle.Brakes attached to each of the four wheels are of two types.In the initial type,a pair of shoes carried on a stationary plate is expanded in contact with a rotating drum mounted on the wheels to arrest the motion of the drum.In the modern type of brakes,one or more pairs of pads are carried in a caliper attached to the axle or wheel supporting linkage.The sides of the disk mounted on the wheel are griped by these pads.By applying pressure on a pedal,the brakes are applied.A hand lever acting through a separate linkage and locked in the on position is used.
For operating the brake,either mechanical or hydraulic system is used.Mechanical system requiring gearing system for mechanical and hydraulic fluid for the hydraulic brakes are used
Propeller Shaft And Uniwersal Joint
For connecting the output shaft of the gear box to the rear axle,a long shaft known as propeller shaft is used.This shaft is either enclosed in a tubular casing or kept exposed or opened with a universal joint fitted at each end for allowing the changes in the shaft alignment with the rise and fall of the rear axle due to road surface variations.Universal joints cannot be eliminated even if the final drive gears are fixed to the frame with the wheel springing independently.Neither the misalignment resulting from the flexing of the vehicle structure over bumpy road surfaces can be avoided nor the precise alingnment of shaft can be ensured without them.
For preventing the transmission of shock from uneven road surfaces to the vehicle,springs are used to support the vehicle on the axle.
In order to allow for the vertical movements of the wheels relative to the frame as well as to allow the parts of the shaft to operate at different angle,another increasingly used arrangement is used.It consists of mounting the final-drive gears and the differential gear in a casing attached to the frame with independently sprung wheels attached to them by means of shafts through devices called universal joints.
Wheels
The wheels which are four in number are fitted below the car chassis to support the load of the vehicle and passengers as well as to run the car.They arefitted with hollow rubber tyres filled with air in rubber tubes under sufficient pressure necessary for carrying the load.Theshocks caused by road irregularities are absorbed by them.By fitting springs between the wheels and the vehicle allowing the vertical movement of wheels in relation to vehicle,greater part of unevenness of road surfaces is taken care of.
When going round a curve,the inner wheel has to travel a smaller distance in comparison to the outer wheel.But both the rear wheels would rotate at the same speed if they are connected by a shaft.This rotation of both the wheels would result in slipping of one or both of them on the road surface causing excessive tyre wear as well as severe twisting loads on the shaft.Moreover,the two wheels of the exactly similar diameter(which is not usually so)can only turn at the same spdde witheout slip on the straight road.Tyres fitted on the opposite sides may be of different states of wear and even tyre of same nominal diameter made by different or same manufacturer may differ in actual dimensions or may not be exactly similar.Due to change of rolling radius(the distance from the wheel center to the ground)the effective size of the tyre many be altered by different inflation pressure also.
Through the above exposition know, Vehicle performance depends not only on the merits of the auto component parts of the performance, and to a large extent depend on the components of the coordination and cooperation depends on the overall layout; The overall design of the level of vehicle design quality, performance and vitality products play a decisive impact.
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