畢業(yè)設計（論文）外文資料翻譯系別： 機械工程系 專業(yè)： 機械設計制造及其自動化 班級： 姓名： 學號： 外 文 出 處 ： English in Mechanical and ElectricalEngineering 附 件 ： 1、 外 文 原 文 ； 2、 外 文 資 料 翻 譯 譯 文 。指導教師評語：簽字： 年 月 日The Automobile ComponentsEngineThe engine is a power plant, which provides power to drive the automobile. 1In most automobile engines, the explosive power of the mixture of air and gasoline drives the pistons. The pistons turn a crankshaft to which they are attached. The rotating force of the crankshaft makes the automobile’s wheels turn.Some automobiles are powered by another kind of engine, known as the rotary valve, rotating combustion engine or Wankel engine. The rotary valve engine also draws in a mixture of air and fuel, which is then compressed and burnt. A motor revolving in an elliptical chamber is connected to a shaft, which finally drives the rear wheels. In most automobiles, the engine is mounted at the front end of the car, with the clutch and gearbox immediately behind it; the engine, clutch and gearbox are assembled into a single unit.A number of systems are necessary to make an engine work. A lubrication system is needed to reduce friction and prevent engine wear. A cooling system is required to keep the engine’s temperature within safe limits. The engine must be provided with the correct amount of air and fuel by a fuel system.The mixture of air and fuel must be ignited inside the cylinder at just the right time by an ignition system. Finally, an electrical system is required to operate the cranking motor that starts the engine and to provide electrical energy to power engine accessories.Lubrication SystemAn engine has many moving parts which eventually develop wear, as they move against each other. The engine circulates oil between these moving parts to prevent the metal-to-metal contact that results in wear. Parts that are oiled can move more easily with less friction and hence power loss due to friction is minimized. The secondary function of lubricant is to act as a coolant and also as a sealing medium to prevent leakages. Finally, a film of lubricant on the cylinder walls helps the rings in sealing and thus improves the engine’s compressions.Cooling SystemDue to the combustion of fuel with air inside the cylinder, the temperature of the engine parts increases. This increase of temperature directly affects the engine performance and the life of the engine parts. The cooling system keeps the engine operating at the efficient temperature. Whatever the driving conditions, the system is designed to prevent both overheating and overcooling.Fuel SystemThe main function of the fuel supply system is to provide fuel to the carburetor or injection system at a rate and pressure sufficient to meet engine demands under all conditions of load, speed 2and gradients encountered by the vehicle. The fuel system must also have enough reserve fuel for several miles of vehicle operation.Ignition SystemThe purpose of the ignition system is to provide assistance for the combustion of fuel either by a high voltage spark or self-ignition in each of the engine’s cylinder at the right time so that the air-fuel mixture can burn completely.The fuel supplied to the combustion chamber must be ignited to deliver power. In a spark-ignition engine an electric spark is used for this purpose. The compression-ignition engine does not require a separate ignition system because the ignition is affected by compression of the mixture to a high pressure.Electrical SystemThe engine’s electrical system provides energy to operate a starting motor and to power all the accessories. The main components of the electrical system are a battery, an alternator, a starting motor, ignition coil and heater.FrameThe frame provides a foundation for the engine and the body of the vehicle. The frame is constructed from square or box-shaped steel members strong enough to support the weight of the body and other components.The automobile frame is usually made up of a number of members welded or riveted together to give the final shape. The engine is mounted on the frame with rubber pads which absorb vibrations and also provide damping of these vibrations. Absorption and damping of vibrations protects passengers from discomfort caused by shocks.The frame is supported on wheel axles by means of springs. This whole assembly is called the chassis. Suspension SystemThe function of the suspension system is to absorb vibrations due to the up and down motion of wheels, caused by the irregularities in the road surface. The springs, connecting linkages, and shock absorber comprise the suspension system of a vehicle. The suspension system is of two types：(1) Rigid system(2) Independent system3In the rigid system, the road springs are attached to a rigid beam axle. It is mostly used in the front axle of commercial vehicles and in the car axle of all types of vehicles. The independent system does not have a rigid axle. Each wheel is free to move vertically without any reaction on its mating wheel. The independent system is mostly used in small cars.Power TrainThe power train carries the power that the engine produces to the car wheels. It consists of the clutch (on cars with a manual transmission), transmission (a system of gears that increases the turning effort of the engine to move the automobile), drive shaft, differential and rear axle.ClutchA clutch is required with the manual transmission system to temporarily disconnect the engine from wheels. Such disengagement of the power train from the engine is essential while changing the gear ratio or while stopping the vehicle.TransmissionThe main function of the transmission is to provide the necessary variation to the torque applied by the engine to the wheels. This is achieved by changing the gearing ratio between the engine output shaft and the drive shaft.Drive ShaftThe drive shaft or propeller shaft connects the gearbox and the differential unit. The drive shaft has universal joints at its ends.DifferentialThe function of the differential is to split the power received from the propeller shaft to the rear axle shaft. It allows the rear wheels to be driven at different speeds when the vehicle takes a bend or falls into a ditch.AxlesAxles are the shafts on which road wheels are mounted. The road wheels are provided with the required drive through these axles.WheelsThe automobile wheels take the load of the vehicle and also produce tractive force to move the vehicle. The wheels are also used for retardation and for stopping the vehicle.Steering System4The steering system is used for changing the direction of the vehicle. The major requirements in any steering mechanism are that it should be precise and easy to handle, and that the front wheels should have a tendency to return to the straight-ahead position after a turn. A gear mechanism, which is known as steering gear, is used in this system to increase the steering effort provided by the driver. This system makes the vehicle steering very easy as the driver does not have to put in much effort. Vehicle steering is not only required on a curved road but also while maneuvering on the busy traffic roads. The steering system allows the vehicle to be guided i.e. to be turned left or right.Braking SystemBrakes are required for slowing down or stopping a moving vehicle. The braking system may be operated mechanically or hydraulically. 95 percent of the braking systems in use today are of the hydraulic type. All brakes consist of two members, one rotating and the other stationary.There are various means by which the two members can be brought in contact, thus reducing the speed of the vehicle. The major components of the braking system are: brake pedal，master cylinder，wheel cylinder，brake drum，brake pipe，brake shoes，brake packing plant and linkages. As the load on the vehicle and the vehicle speed has increased according to recent trends, in modern days, the importance of the braking system has also increased and power brakes are now being preferred. Power brakes utilize vacuum and air pressure to provide most of the brake——applying effort.Virtual ManufacturingWhat is Virtual ManufacturingVirtual manufacturing (VM) is an integrated, synthetic manufacturing environment exercised to enhance all levels of decision and control in a manufacturing enterprise. VM can be described as a simulated model of the actual manufacturing setup which may or may not exist. It holds all the information relating to the process, the process control and management and product specific data. It is also possible to have part of the manufacturing plant be real and the other part virtual. Virtual manufacturing is the use of computer models and simulations of manufacturing process to aid in design and production of manufactured products.Lawrence Associate [1996], have identified three different types of Virtual Manufacturing 5paradigms that use Virtual Reality technology to provide the integrated environment.(1) Design—centered VM：provides designers with the tools to design products that meet design criteria such as design for X;(2) Production—centered VM: provides the means develop and analyze alternative production and process plans;(3) Control—centered VM：allows the evaluation of product design, production plans, and control strategy and a means to iteratively to iteratively improve all of them through the simulation of the control process.What is the Significance of VMVM aims at providing an integrated environment for a number of isolated manufacturing technologies such as Computer Aided Design, Computer Aided Manufacturing, and Computer Aided Process Planning, thus allowing multiple users to concurrently carry out all or some of these functions without the need for being physically close to each other. For example, a process planning engineer and a manufacturing engineer can evaluate and provide feedback to a product designer, who may be physically located in another state or country, at the same time as the design is being conceived.Another important contribution of VM is Virtual Enterprise (VE). Lin et al .[1995] defined a Virtual Enterprise as“rapidly configured multi—disciplinary network of small, process specific firms configured to meet a window of opportunity to design and produce a specific product.” Using this technology , a group of people , or corporations can pool their expertise and resources and capitalize a market opportunity, by sharing information in a VM environment. The principal advantage of this technology is its ability to provide a multi-media environment, enhancing communication at all levels in a product’s life cycle.Applications of VMApplication of VM encompass the entire life cycle of a product. Reported developments include a virtual space decision support system by Imamura and Nomura[1994] at the Matsushita company in Japan. This system applied towards the marketing and sales of kitchen furniture, allows customers to experience a kitchen environment and evaluate alternatives and select the best combination according to preferences. Their preferences are stored as drawings and subsequently transferred to the company’s production facilities. Owen [1994] presented the work implemented at John Deere Company’s production facility, 6that used Virtual Manufacturing for the installation of an arc welding production system. The project involved using a Virtual 3-D environment for design, evaluation, and testing of the robotic production system. Part of the work was carried out at John Deere’s facility while part of it was done by Genesis System and Technomatrix Technologies. The VM approach helped shorten the design-to-manufacturing cycle-time.DuPont [1994] presented an overview of Virtual Reality applications, and reported about Virtual prototyping being carried out at the Coventry School of Art and Design. These virtual prototypes are constructed in a computer at the beginning of the design process and allow the designer to perform tests on the virtual prototype such as a car before hand , by walking around or through the design, examine its performance on a virtual road , sit in the driver’s seat , and check view lines, etc. Also reported were VM applications such as the virtual concurrent design and assembly of a landing gear, and simulation of side-impact collision to test vehicle safety.Kim et al. [1994] also reported VR applications including the use of VM by designers at Boeing Aircraft Company for the ergonomic evaluation of their airplane designs for operation as well as maintenance. Another study used a VM environment to train robots. An operator’s movements were recognized, interpreted and stored in the form of robotic movement commands. Shenai described the Virtual Wafer Fabrication (VWF) infrastructure which provided an framework for the optimization of key process and design variables in the development of application specific semi-conductor devices. Other application areas discussed in Larijani [1994] include machine-vision applications for diagnosis, fault detection, inspection and preventive maintenance, safety and maintenance training, ergonomic analysis For example , new cab or shovel configurations for each Caterpillar moving equipment are tested by real drivers for possible imbalances while handling virtual bulldozers and trucks.0汽車的部件發(fā)動機發(fā)動機的作用是為汽車提供動力，人們形象的稱之為汽車的動力工廠。大多數(shù)汽車發(fā)動機都是利用空氣和汽油混合物的爆炸能量推動活塞的?；钊軌蜣D(zhuǎn)動與它連接在一起的曲柄連桿。從而，曲柄產(chǎn)生牽引力使車輪轉(zhuǎn)動。有些汽車是靠另一種發(fā)動機來提供動力的。這種發(fā)動機因為它的旋轉(zhuǎn)閥，旋轉(zhuǎn)內(nèi)燃機或者轉(zhuǎn)子發(fā)動機而被人熟知。這種旋轉(zhuǎn)閥式發(fā)動機也能夠吸入空氣和燃料的混合物，然后將它們壓縮并燃燒。另外，發(fā)動機會在一個橢圓形腔室中旋轉(zhuǎn)，它與驅(qū)動汽車后輪的后軸相連接。絕大多數(shù)的汽車里，發(fā)動機會被安裝在汽車的前部末端，離合器和變速箱在它的后面。最后，發(fā)動機、離合器和變速箱會被裝配成一個整體。想要使一個發(fā)動機能夠正常工作還需要很多系統(tǒng)的支持。潤滑系統(tǒng)可以用來減小摩擦，減輕發(fā)動機磨損。冷卻系統(tǒng)可以使發(fā)動機的工作溫度在安全的范圍之內(nèi)。另外，發(fā)動機還必須由供油系統(tǒng)提供適量的燃料和空氣。在氣缸里，空氣和燃料的混合物必須由點火系統(tǒng)在適當?shù)那闆r下點燃。而后，電子系統(tǒng)被用來控制啟動發(fā)動機用的電動機和為發(fā)動機的附屬部件提供電能。潤滑系統(tǒng)發(fā)動機的部件會因為它們之間的相互運動而逐漸導致磨損。在這些部件中間存在著發(fā)動機循環(huán)油。它可以避免金屬間的相互摩擦而導致的磨損。在潤滑劑的潤滑作用下，各部件會僅受到很小的摩擦力，這可以使它們更容易運動。因此，潤滑系統(tǒng)可以將由摩擦引起的能量損失降到最小。潤滑劑的第二個作用是可以發(fā)揮冷卻劑的作用，也可以作為密封介質(zhì)來防止泄漏。還有在氣缸上產(chǎn)生的潤滑薄膜也可以有助于活塞環(huán)密封，改善發(fā)動機的壓縮性能。冷卻系統(tǒng)在氣缸中，燃料會在空氣的作用下劇烈燃燒，從而導致發(fā)動機各部件的溫度升高。溫度的上升將直接影響發(fā)動機的性能，也會縮短發(fā)動機零件的壽命。而冷卻系統(tǒng)則可以使發(fā)動機在適宜的溫度下工作。無論駕駛條件如何，該系統(tǒng)都要被設計用來防止機器過冷或過熱。燃料供給燃料供給系統(tǒng)的主要作用是在機動車輛所能遇到的所有條件下（包括負載，速度，溫1度壓力的變化梯度等） ，提供足夠的壓力，以一定的速度為化油器或注油系統(tǒng)提供燃料，來滿足發(fā)動機的燃料要求。另外，燃料系統(tǒng)還必須儲備足夠的燃料，以便可以支持車輛能夠行駛數(shù)英里。點火系統(tǒng)點火系統(tǒng)的目的是能在適當?shù)臅r間里通過高壓電火花或自燃，使每個內(nèi)燃機氣缸中的燃料。燃燒以便氣缸中的液氣混合物得到充分的燃燒。供給到燃燒室的燃料必須經(jīng)過燃燒才能釋放出能量。在火花點火發(fā)動機中，點火系統(tǒng)是利用電火花來點燃燃料的。壓縮點火發(fā)動機則沒必要擁有獨立的點火系統(tǒng)。因為它其中的混合物是靠壓縮產(chǎn)生足夠的壓力來點燃的。電氣系統(tǒng)發(fā)動機的電氣系統(tǒng)可以提供足夠的電力用來啟動電動機和操縱其他全部的附屬部件。電氣系統(tǒng)的主要元件有電池、交流發(fā)電機、啟動電動機、點火線圈和加熱器。車架車架是為發(fā)動機和車身提供了一個安裝的基礎。車架是由數(shù)量眾多的足夠強大的方形和箱形鋼構(gòu)件組成的，這樣才能夠有效地用來支撐車身和其他構(gòu)件的重量。汽車車架通常是由大量的鋼構(gòu)件經(jīng)過焊接或鉚接在一起的，從而形成最后的車體形狀。一般發(fā)動機都將安裝在有橡膠墊的車架上，橡膠墊吸收震動的同時也可以減小這些震動的發(fā)生。故吸收和減弱這些震動可以有效的幫助乘客減弱因為行駛中的顛簸而感到的不適。這些車架是由車輛輪軸上很多彈簧支撐的。所有這些裝配在一起稱為車輛底盤。懸掛系統(tǒng)懸掛系統(tǒng)的作用是可以吸收車輛在不平整路面上行駛時，由于車輪上下顛簸而產(chǎn)生的震動。彈簧的連接裝置和減震器構(gòu)成了車輛的懸掛系統(tǒng)。懸掛系統(tǒng)通常有兩種類型組成：（1） 剛性系統(tǒng)（2） 獨立系統(tǒng)在剛性系統(tǒng)中，彈簧連接在一根剛性橫梁軸上。這種系統(tǒng)大多應用于商用車輛的前軸以及各類車輛車軸上。獨立系統(tǒng)則不需要擁有剛性橫梁軸。每一個車輪可以自由的垂直運動，而相對應的另一側(cè)車輪沒有任何反應。獨立系統(tǒng)大多應用于小型車輛。2動力傳動系統(tǒng)動力傳動系統(tǒng)的作用是可以用來將發(fā)動機產(chǎn)生的能量傳遞給車輪。它包括離合器（汽車上的手動變速器） 、差動器（能提高發(fā)動機產(chǎn)生的轉(zhuǎn)矩以催動汽車的齒輪系） 、驅(qū)動軸、差速器、后橋。離合器離合器是用于手動變速的傳動裝置，可以用來暫時切斷發(fā)動機和車輪間的動力傳遞。在需要換擋或停車時，把傳動系統(tǒng)和發(fā)動機的連接斷開是極其重要的。變速器變速器的主要作用是通過發(fā)動機把各種必需的扭矩傳遞給車輪。通常情況下，這是通過改變發(fā)動機輸出軸和驅(qū)動軸間的齒輪傳動比來實現(xiàn)的這些必要的差異的。驅(qū)動軸驅(qū)動軸或推動軸一般與齒輪變速箱和差速器相連，而在驅(qū)動軸的兩端也常設計有萬向節(jié)。差速器差速器的作用是把來自傳動軸的能量分給后橋。當汽車轉(zhuǎn)彎時或跌入水溝中，兩個后輪可以以不同的速度驅(qū)動。車橋車輪被安裝在一根軸上，該軸被稱為車橋。車橋的各車輪提供必需驅(qū)動力。車輪汽車車輪需要支承整輛車，并產(chǎn)生牽引力來驅(qū)動車輛行駛。另外，車輪也用來減速和停車。轉(zhuǎn)向系統(tǒng)轉(zhuǎn)向系統(tǒng)用來改變車輛的行駛方向。在任何轉(zhuǎn)向裝置中，一般都要求轉(zhuǎn)向精確和便于操縱，并且在每轉(zhuǎn)一次向后，前輪都應該有一種自動返回到原先直線行駛的位置的趨勢。齒輪機構(gòu)通常以轉(zhuǎn)向齒輪而聞名，通常在轉(zhuǎn)向過程中，能夠增大轉(zhuǎn)向的作用力矩。還有這套系統(tǒng)可以讓駕駛員不必花費太大的氣力就可以輕松地使車輛轉(zhuǎn)向。轉(zhuǎn)向系統(tǒng)極為重要，不僅僅在彎道行駛中需要轉(zhuǎn)向系統(tǒng)，在擁擠的交通道路上汽車行駛時同樣也需要它。另外，轉(zhuǎn)向系統(tǒng)能使車輛向左或向右轉(zhuǎn)向。3制動系統(tǒng)制動系用來使汽車減速或停車。制動系統(tǒng)分為機械式和液壓式兩種。目前 95%的制動系統(tǒng)都屬于液壓式的。制動系統(tǒng)包括兩部分，轉(zhuǎn)動部分和固定不動的部分。人們都通過各種方式使上述兩部分緊密接觸，從而可以減小車輛的行駛速度。制動系統(tǒng)的主要制動元件有：制動踏板、主制動缸、車輪制動、制動鼓、制動路、制動蹄、制動裝備和聯(lián)動裝置等。目前，車輛的負載和速度都有逐漸提高的趨勢。目前，制動系統(tǒng)的重要性也益顯現(xiàn)出來。并且人們更喜歡助力制動器。助力制動器將用來提供更好的制動力。虛擬制造 什么是虛擬制造 虛擬制造（VM）是一個使 用 感 官 仿 真 設 備 和 真 實 或 虛 幻 環(huán) 境 的 動 態(tài) 模 型 生 成 或 創(chuàng)造 出 人 能 夠 感 知 的 環(huán) 境 或 現(xiàn) 實 ， 使 人 能 夠 憑 借 直 覺 作 用 于 計 算 機 產(chǎn) 生 的 三 維 仿 真 模 型 的虛 擬 環(huán) 境 。 這 種 技 術(shù) 可以提高制造企業(yè)的決策和控制水平。虛擬制造是用來模擬實際生產(chǎn)制造活動，能夠讓人們判斷某種產(chǎn)品在實際生產(chǎn)中是否可以有效的制造出來。虛擬制造技術(shù)必須擁有實際生產(chǎn)活動中的所有有關(guān)信息，如過程控制和管理、產(chǎn)品的具體數(shù)據(jù)。在運用虛擬制造的過程中，所知性的生產(chǎn)計劃中有一部分是真實的，另一部分是虛擬的。在計算機模型和模擬生產(chǎn)制造過程中經(jīng)常使用虛擬制造技術(shù)，可以幫助設計和制造產(chǎn)品。 勞倫斯準[1996]，確定了三種不同類型的虛擬制造模式。這三種模式都是利用虛擬現(xiàn)實技術(shù)來模擬虛擬的生產(chǎn)制造環(huán)境的。 （1）以設計為中心的虛擬制造：為設計者提供適當?shù)墓ぞ邅碓O計不同的產(chǎn)品； （2）以生產(chǎn)為中心的虛擬制造：以虛擬制造的開發(fā)和分析手段來替代實際的生產(chǎn)和加工；（3）以控制為中心的虛擬制造：通過模擬產(chǎn)品的生產(chǎn)過程，可以對產(chǎn)品設計過程進行評價，從而不斷的改善生產(chǎn)計劃和控制手段，使生產(chǎn)過程得到改善。虛擬制造的重要意義 虛擬制造旨在將 與 產(chǎn) 品 制 造 相 關(guān) 的 各 種 技 術(shù) 集 成 統(tǒng) 一 起 來 ，如計算機輔助設計，計算機輔助制造和計算機輔助工藝設計。從而使多個用戶不再需要物理上的接觸，就可以共同進行全部或其中部分的工作。例如，工藝設計工程師和制造工程師可以一起評估和共享4產(chǎn)品的設計信息，他們很有可能不在同一個國家或地區(qū)，卻可以在同一時間進行同一產(chǎn)品的設計。 虛擬機的另一個重要貢獻是虛擬企業(yè)（VE） 。Linetal [1995]將虛擬企業(yè)定義為“需要各種學科之間的廣泛配合，為企業(yè)設計和生產(chǎn)產(chǎn)品提供機會的窗口” 。在運用這項技術(shù)時，一群人或一個公司可以分享虛擬環(huán)境的信息，以便集中他們的專長和資源，及時的把握市場機遇。這項技術(shù)的主要優(yōu)勢在于它能夠提供一個多媒體的環(huán)境，提高產(chǎn)品在生命周期中各個階段階的信息溝通。 虛擬制造的應用 虛擬制造技術(shù)應用在產(chǎn)品的整個生命周期中。在[1994 年]松下公司發(fā)展報告中，該公司決定采用虛擬空間決策的支持系統(tǒng)。這套系統(tǒng)應用在營銷和廚房家具銷售上，使客戶能夠切身體驗到廚房環(huán)境和評價辦法，并根據(jù)他們各自的喜好選擇最佳組合。他們通常都將其存儲為圖紙，隨后移交給公司的生產(chǎn)機構(gòu)。 歐文[1994]在提交約翰迪爾公司的有關(guān)生產(chǎn)落實的工作報告中，提出在電弧焊接生產(chǎn)系統(tǒng)中采用虛擬制造技術(shù)。該項目涉及到一個虛擬的三維設計、評估環(huán)境系統(tǒng)以及機器人生產(chǎn)系統(tǒng)的測試。其中部分的工作在約翰迪爾公司的設施中進行，而這部分將由創(chuàng)世紀系統(tǒng)和 Techno 矩陣技術(shù)工作。在虛擬制造的幫助，能夠縮短從產(chǎn)品設計到產(chǎn)品制造的時間。杜邦[1994]提出了虛擬現(xiàn)實應用的概述，并報道了在考文垂藝術(shù)與設計學院內(nèi)正在進行的虛擬樣機。這些虛擬原型在一臺計算機中進行，在設計過程的開始時，設計師將設計出一條虛擬道路及道路上的各種元素，如道路上行駛的二手車，行人等等。然后坐在駕駛座上，查看行駛路線等行為來執(zhí)行虛擬樣機試驗，通過研究駕駛員在虛擬道路上的表現(xiàn)，來設計和組裝起落架，測試汽車碰撞時的安全性。 Kim[1994]的報告中指出，波音飛機公司的設計人員也在利用虛擬制造技術(shù)進行設計。虛擬制造技術(shù)可以提供符合人體工程學的飛機設計、評價應用以及維護。另一項研究中使用了虛擬環(huán)境，即訓練機器人。一個操作員的的動作將會得到識別、解釋，最后存儲在機器人行動命令中。 Shenai 描述了虛擬制造為（血友病）基礎設施提供了一個關(guān)鍵的工藝和設計變量，在應用中能夠使具體的半導體器件得到優(yōu)化。拉里賈尼[1994]討論虛擬制造技術(shù)還應用在其他領域中，包括機器視覺應用的診斷，故障檢測，檢查和預防性維修，安全及維修訓練，例如人體工程學的分析，通過虛擬的推土機和卡車，來模擬現(xiàn)實中駕駛員在新的駕駛室或新的配置下，能否工作舒適或能否進行穩(wěn)定操作。