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編號
無錫太湖學(xué)院
畢業(yè)設(shè)計(論文)
相關(guān)資料
題目: 四驅(qū)越野汽車變速器
及操縱系統(tǒng)的設(shè)計
信機 系 機械工程及自動化專業(yè)
學(xué) 號: 0923069
學(xué)生姓名: 柴亦浩
指導(dǎo)教師: 過金超 (職稱:副教授)
(職稱: )
2013年5月25日
目 錄
一、畢業(yè)設(shè)計(論文)開題報告
二、畢業(yè)設(shè)計(論文)外文資料翻譯及原文
三、學(xué)生“畢業(yè)論文(論文)計劃、進度、檢查及落實表”
四、實習(xí)鑒定表
無錫太湖學(xué)院
畢業(yè)設(shè)計(論文)
開題報告
題目: 四驅(qū)越野汽車變速器
及操縱系統(tǒng)的設(shè)計
信機 系 機械工程及自動化 專業(yè)
學(xué) 號: 0923069
學(xué)生姓名: 柴亦浩
指導(dǎo)教師: 過金超(職稱: )
(職稱: )
2013年5月25日
課題來源
實驗室課題。
科學(xué)依據(jù)
隨著經(jīng)濟和科學(xué)技術(shù)的不斷的發(fā)展,汽車工業(yè)也漸漸成為我國支柱產(chǎn)業(yè),汽車的使用已經(jīng)遍布全國。而隨著我國加入WTO,人民生活水平的不斷提高,微型客貨兩用車、轎車等高級消費品已進入平常家庭。在我國,汽車工業(yè)起步較晚。入世后,我國的汽車工業(yè)面臨的是機遇和挑戰(zhàn)。隨著我國汽車工業(yè)不斷的壯大,以及汽車行業(yè)持續(xù)快速的發(fā)展,如何設(shè)計出經(jīng)濟實惠,工作可靠,性能優(yōu)良,且符合中國國情的汽車已經(jīng)是當前汽車設(shè)計者的緊迫問題。在面臨著前所未有的機遇同時,不得不承認在許多技術(shù)上,我國與發(fā)達國家還一定的差距,所以我們要努力為我國的汽車工業(yè)做出應(yīng)有的貢獻。而在本課題的學(xué)習(xí)中,我將重點研究汽車的變速器部分。
變速器是汽車傳動系統(tǒng)中關(guān)鍵的零部件,它用來改變發(fā)動機傳到驅(qū)動輪上的轉(zhuǎn)矩和轉(zhuǎn)速,目的是在原地起步,爬坡,轉(zhuǎn)彎,加速等各種行駛工況下使汽車獲得不同的牽引力和速度,同時使發(fā)動機在最有利的工況范圍內(nèi)工作。由于變速器在汽車的運行中扮演著非常重要的角色。所以很多汽車常見的故障也來源于此。而技術(shù)先進的變速箱不僅能夠降低汽車的故障而且還能夠降低動力損失,減少燃油消耗。正因為如此,現(xiàn)在不少的客車用戶在選擇車輛的時候,變速箱都是一項重要的指標。
目前在汽車上使用的變速箱大致可以分為兩類:手動變速箱和自動變速箱。其中,自動變速箱由于駕駛員操作簡便,從而裝備這種變速箱的車輛能夠大大提高駕乘舒適性。但是自動變速箱的結(jié)構(gòu)比較復(fù)雜,對技術(shù)要求和制造工藝都有較高的要求,而且造價和使用維修費用昂貴。對于手動檔來說,其優(yōu)點主要有:1.結(jié)構(gòu)簡單,制造成本低;2.易于安裝,維修方便;3.傳動效率高,經(jīng)濟節(jié)油,能延長車輛的使用壽命。據(jù)Global insight公司亞洲區(qū)技術(shù)分析師分析稱目前在中國,短期內(nèi),自動檔變速器的市場是十分樂觀的。但同時手動檔變速器的節(jié)能型,經(jīng)濟性以及駕駛娛樂性也決定了其不可替代性。手動檔變速器仍然占據(jù)主要份額。所以對于手動變速器的研究和設(shè)計依然十分重要。
而本課題就是要求設(shè)計出一款四驅(qū)越野車變速器,本設(shè)計可以通過對《汽車構(gòu)造》、《汽車理論》、《汽車設(shè)計》、《機械設(shè)計》、《液壓傳動》等課程知識的綜合運用完成設(shè)計,達到綜合訓(xùn)練的效果,并且為以后的相關(guān)工作和學(xué)習(xí)積累寶貴的經(jīng)驗。
研究內(nèi)容
1、基本內(nèi)容
(1)變速器的概述及其方案的確定
變速器的功用和要求;變速器結(jié)構(gòu)方案的確定;變速器主要零件結(jié)構(gòu)的方案分析。
(2) 變速器主要參數(shù)的選擇與主要零件的設(shè)計
變速器主要參數(shù)的選擇(檔數(shù)和傳動比、中心距、軸向尺寸、齒輪參數(shù));各檔傳動比及其齒輪齒數(shù)的確定;齒輪變位系數(shù)的選擇。
(3) 變速器齒輪的強度計算與材料的選擇
齒輪的損壞原因及形式;齒輪的強度計算與校核。
(4) 變速器軸的強度計算與校核
變速器軸的結(jié)構(gòu)和尺寸; 軸的校核.。
(5)變速器同步器的設(shè)計及操縱機構(gòu)
同步器的結(jié)構(gòu);同步環(huán)主要參數(shù)的確定;變速器的操縱機構(gòu)。
(6)變速器箱體設(shè)計
箱體材料與毛坯種類;箱體主要結(jié)構(gòu)尺寸與計算。
2、擬解決的主要問題:
(1)完成變速器的結(jié)構(gòu)分析與型式選擇;
(2)計算變速器的基本參數(shù),完成變速器齒輪的設(shè)計計算;
(3)完成變速器軸與軸承的結(jié)構(gòu)形式選擇、強度校核計算;
(4)完成同步器的結(jié)構(gòu)型式選擇;
(5)繪制總裝配圖及零件圖。
擬采取的研究方法、技術(shù)路線、實驗方案及可行性分析
變速器設(shè)計是一個重要的課題,因此要充分利用現(xiàn)有參考文獻,資料進行認識,不斷地分析增進對變速器的了解。在對變速器有了較深刻的理解后開始對變速器的各個部分進行分布設(shè)計。本設(shè)計按以下方案依次進行:
調(diào)查分析,收集資料
變速器總體方案選擇及設(shè)計
變速器的結(jié)構(gòu)設(shè)計與計算
確定變速器的主要參數(shù)
變速器的校核,確定最終準確的設(shè)計參數(shù)
運用Pro/e進行三維建模
運用Ansys軟件進行校核
是
否
運用CAD軟件繪出變速器裝配及零件圖
研究計劃及預(yù)期成果
研究計劃:
2012年10月12日-2012年12月25日:按照任務(wù)書要求查閱論文相關(guān)參考資料,填寫畢業(yè)設(shè)計開題報告書。
2013年1月11日-2013年3月5日:填寫畢業(yè)實習(xí)報告。
2013年3月8日-2013年3月14日:按照要求修改畢業(yè)設(shè)計開題報告。
2013年3月15日-2013年3月21日:學(xué)習(xí)并翻譯一篇與畢業(yè)設(shè)計相關(guān)的英文材料。
2013年3月22日-2013年4月11日:CAD程序設(shè)計。
2013年4月12日-2013年4月25日: 論文定向設(shè)計。
2013年4月26日-2013年5月21日:畢業(yè)論文撰寫和修改工作。
預(yù)期成果:
在國內(nèi),仍然以手動變速器為主,自動變速器比例很低,并且主要來自進口。中國乘用車用手動檔變速器生產(chǎn)企業(yè)分為兩類,一類是像一汽、東風(fēng)、上汽等整車生產(chǎn)集團,集團內(nèi)自產(chǎn)變速器為其整車配套;另外一類是獨立的變速器生產(chǎn)企業(yè),專門為各整車廠配套。其中以一汽集團作為代表,一汽集團除了主要研究手動變速器以外,更以6AT、AMT和7DCT作為開發(fā)重點。其發(fā)展趨勢為:a.以手動變速器開發(fā)為基礎(chǔ),以自動變速器開發(fā)為重點b.重點提升制造能力和水平c.重點發(fā)展DCT、AMT,適時發(fā)展AT。d.產(chǎn)品平臺系列化,適用面更廣。目前雖然我國手動變速器技術(shù)發(fā)展已日益成熟,但相對發(fā)達國家水平依然存在一定的差距,因此對于手動變速器的研究依然十分重要。
對汽車變速器有一個系統(tǒng)性的理解,在CAD制圖方面知識得到了完善。
特色或創(chuàng)新之處
在手動變速器方面,一方面是系統(tǒng)集成性,安裝性還有發(fā)展空間,另外就是新的材料、工藝,比如沖壓零件,注塑零件替代產(chǎn)品的加工工藝。
變速器發(fā)展總體趨勢主要體現(xiàn)以下6個方面:產(chǎn)品系列化;結(jié)構(gòu)緊湊化、輕量化、
多檔化;高度集成化;更加智能化;信息網(wǎng)絡(luò)化;節(jié)能環(huán)?;?。
已具備的條件和尚需解決的問題
由于機械部分設(shè)計、工藝已經(jīng)相當成熟,在要有突破性的發(fā)展空間已經(jīng)非常小了,因為整車開發(fā)的需要,降低排放,油耗是目前發(fā)展方向,所以有更多的廠商也將當前的目標瞄準了DCT。
指導(dǎo)教師意見
指導(dǎo)教師簽名:
年 月 日
教研室(學(xué)科組、研究所)意見
教研室主任簽名:
年 月 日
系意見
主管領(lǐng)導(dǎo)簽名:
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英文原文
AUTOMATIC TRANSMISSION
The modern automatic transmission is by far,the most complicated mechanical component in today’s automobile.It is a type of transmission that sifts itself.A fluid coupling or torque converter is used instead of a manually operated clutch to connect the transmission to the engine.
There are two basic types of automatic transmission based on whether the vehicle is rear wheel drive or front wheel drive.On a rear wheel drive car,the transmission is usually mounted to the back of the engine and is located under the hump in the center of the floorboard alongside the gas pedal position.A drive shaft connects the transmission to the final drive which is located in the rear axle and is used to send power to the rear wheels.Power flow on this system is simple and straight forward going from the engine,through the torque converter,then trough the transmission and drive shaft until it reaches the final drive where it is split and sent to the two rear transmission.
On a front wheel drive car,the transmission is usually combined with the final drive to form what is called a transaxle.The engine on a front wheel drive car is usually mounted sideways in the car with the transaxle tucked under it on the side of the engine facing the rear of the car.Front axles are connected directly to the transaxle and provide power to front wheels.In this example,power floes from the engine,through the torque converter to a larger chain that sends the power through a 180 degree turn to the transmission that is along side the engine.From there,the power is routed through the transmission to the final drive where it is split and sent to the two front wheels through the drive axles.
There are a number of other arrangements including front drive vehicles where the engine is mounted front to back instead of sideways and there are other systems that drive all four wheels but the two systems described here are by far the most popular.A much less popular rear and is connected by a drive shaft to the torque converter which is still mounted on the engine.This system is found on the new Corvette and is used in order to balance the weight evenly between the front and rear wheels for improved performance and handling.Another rear drive system mounts everything,the engine,transmission and final drive in the rear.This rear engine arrangement is popular on the Porsche。
The modern automatic transmission consists of many components and systems that designed to work together in a symphony of planetary gear sets,the hydraulic system, seals and gaskets,the torque converter,the governor and the modulator or throttle cable and computer controls that has evolved over the years into what many mechanical inclined individuals consider to be an art from.Here try to used simple,generic explanation where possible to describe these systems.
1)Planetary gear sets
Automatic transmission contain many gears in various combinations.In a manual transmission,gears slide along shafts as you move the shift lever from one position to another,engaging various sizes gears as required in order to provide the correct gear ratio.In an automatic transmission,how ever,the gears are never physically moved and are always engaged to the same gears.This is accomplished through the use of planetary gear sets.
The basic planetary gear set consists of a sun gear,a ring and two or more planet gears,all remaining in constant mesh.The planet gears are connected to each other through a common carrier which allows the gears to spin on shafts called “pinions” which are attached to the carrier.
One example of a way that this system can be used is by connecting the ring gear to the input shaft coming from the engine,connecting the planet carrier to the output shaft,and locking the sun gear so that it can’t move.In this scenario,when we turn the ring gear,the planets will “walk” along the sun gear ( which is held stationary ) causing the planet carrier to turn the output shaft in the same direction as the input shaft but at a slower speed causing gear reduction ( similar to a car in first gear ).
If we unlock the sun gear and lock any two elements together,this will cause all three elements to turn at the same speed so that to output shaft will turn at the same rate of speed as the input shaft.This is like a car that is third or high gear.Another way we can use a planetary gear set is by locking the planet carrier from moving,then applying power to the ring gear which will cause the sun gear to turn in opposite direction giving us reverse gear.
The illustration in Figure shows how the simple system described above would look in an actual transmission.The input shaft is connected to the ring gear,the output shaft is connected to the planet carrier which is also connected to a “Multi-disk” clutch pack.The sun gear is connected to drum which is also connected to the other half of the clutch pack.Surrounding the outside of the drum is a band that can be tightened around the drum when required to prevent the drum with the attached sun gear from turning.
The clutch pack is used,in this instance,to lock the planet carrier with the sun gear forcing both to turn at the same speed.If both the clutch pack and the band were released,the system would be in neutral.Turning the input shaft would turn the planet gears against the sun gear,but since noting is holding the sun gear,it will just spin free and have no effect on the output shaft.To place the unit in first gear,the band is applied to hold the sun gear from moving.To shift from first to high gear,the band is released and the clutch is applied causing the output shaft to turn at the same speed as the input shaft.
Many more combinations are possible using two or more planetary sets connected in various way to provide the different forward speeds and reverse that are found in modern automatic transmission.
2)Clutch pack
A clutch pack consists of alternating disks that fit inside a clutch drum.Half of the disks are steel and have splines that fit into groves on the inside of the drum.The other half have a friction material bonded to their surface and have splines on the inside edge that fit groves on the outer surface of the adjoining hub.There is a piston inside the drum that is activated by oil pressure at the appropriate time to squeeze the clutch pack together so that the two components become locked and turn as one.
3)One-way Clutch
A one-way clutch ( also known as a “sprag” clutch ) is a device that will allow a component such as ring gear to turn freely in one direction but not in the other.This effect is just like that bicycle,where the pedals will turn the wheel when pedaling forward,but will spin free when pedaling backward.
A common place where a one-way clutch is used is in first gear when the shifter is in the drive position.When you begin to accelerate from a stop,the transmission starts out in first gear.But have you ever noticed what happens if you release the gas while it is still in first gear ? The vehicle continues to coast as if you were in neutral.Now,shift into Low gear instead of Drive.When you let go of the gas in this case,you will feel the engine slow you down just like a standard shift car.The reason for this is that in Drive,one-way clutch is used whereas in Low,a clutch pack or a band is used.
4)Torque Converter
On automatic transmission,the torque converter takes the place of the clutch found on standard shift vehicles.It is there to allow the engine to continue running when the vehicle comes to a stop.The principle behind a torque converter is like taking a fan that is plugged into the wall and blowing air into another fan which is unplugged.If you grab the blade on the unplugged fan,you are able to hold it from turning but as soon as you let go,it will begin to speed up until it comes close to speed of the powered fan.The difference with a torque converter is that instead of using air it used oil or transmission fluid,to be more precise.
A torque converter is a lager doughnut shaped device that is mounted between the engine and the transmission.It consists of three internal elements that work together to transmit power to the transmission.The three elements of the torque converter are the pump,the Turbine,and the Stator.The pump is mounted directly to the torque housing which in turn is bolted directly to the engine’s crankshaft and turns at engine speed.The turbine is inside the housing and is connected directly to the input shaft of the transmission providing power to move the vehicle.The stator is mounted to a one-way clutch so that it can spin freely in one direction but not in the other.Each of the three elements has fins mounted in them to precisely direct the flow of oil through the converter.
With the engine running,transmission fluid is pulled into the pump section and is pushed outward by centrifugal force until it reaches the turbine section which stars it running.The fluid continues in a circular motion back towards the center of the turbine where it enters the stator.If the turbine is moving considerably slower than the pump,the fluid will make contact with the front of the stator fins which push the stator into the one way clutch and prevent it from turning.With the stator stopped,the fluid is directed by the stator fins to re-enter the pump at a “help” angle providing a torque increase.As the speed of the turbine catches up with the pump,the fluid starts hitting the stator blades on the back-side causing the stator to turn in the same direction as the pump and turbine.As the speed increase,all three elements begin to turn at approximately the same speed.Sine the ‘80s,in order to improve fuel economy,torque converters have been equipped with a lockup clutch which locks the turbine to the pump as the vehicle reaches approximately 40-50 mph.This lockup is controlled by computer and usually won’t engage unless the transmission is in 3 or 4 gear.
5)Hydraulic System
The hydraulic system is a complex maze of passage and tubes that sends that sends transmission fluid and under pressure to all parts of the transmission and torque converter and.Transmission fluid serves a number of purpose including : shift control ,general lubrication and transmission cooling。Unlike the engine ,which uses oil primary for lubrication ,every aspect of a transmission ‘s function is dependant on a constant supply of fluid is send pressure.In order to keep the transmission at normal operating temperature,a portion of the fluid is send to through one of two steel tubes to a special chamber that is submerged in anti-freeze in the radiator.Fluid passing through this chamber is cooled and then returned to the transmission through the other steel tube.A typical transmission has an avenge of ten quarts of fluid between the transmission,torque converter,and cooler tank,In fact,most of the components of a transmission are constantly submerged in fluid including the clutch packs and bands.The friction surfaces on these parts are designed to operate properly only when they are submerged in oil.
6)Oil Pump
The transmission oil pump ( not to confused with the pump element inside the torque converter ) is responsible for producing all the oil pressure that is required in the transmission.The oil pump is mounted to front of the transmission case and is directly connected to a flange on the engine crankshaft,the pump will produce pressure whenever the engine is running as there is a sufficient amount of transmission fluid available.The oil enters the pump through a filter that is located at bottom of the transmission oil pan and travels up a pickup tube directly to the oil pump.The oil is then sent,under pressure to the pressure regulator,the valve body and the rest of the components,as required.
7)Valve Body
The valve body is the control center of the automatic transmission.It contains a maze of channels and passages that direct hydraulic fluid to the numerous valves which when activate the appropriate clutch pack of band servo to smoothly shift to the appropriate gear for each driving situation.Each of the many valves in the valve body has a specific purpose and is named for that function.For example the 2-3 shift valve activates the 2nd gear up-shift or the 3-2 shift timing valve which determines when a downshift should occur.
The most important valve and the one that you have direct control over is the manual valve. The manual valve is directly connected to the gear shift handle and covers and uncovers various passages depending on what position the gear shift is paced in.When you place the gear shift in Drive,for instance,the manual valve directs fluid to the clutch pack ( s ) that activates 1st gear.It also sets up to monitor vehicle speed and throttle position so that it can determine the optimal time and the force for the 1-2 shift.On computer controlled transmission,you will also have electrical solenoids that are mounted in the valve body to direct fluid to the appropriate clutch packs or bands under computer control to more precisely control shift points.
8)Seals and Gaskets
An automatic transmission has many seals and gaskets to control the flow of hydraulic fluid and to keep it from leaking out.There are two main external seals : the front seal and the rear seal.The front seal seals the point where the torque converter mounts to the transmission case.This seal allows fluid to freely move from the converter to the transmission but keeps the fluid from leaking out.The rear seal keeps fluid from leaking past the output shaft.
A seal is usually made of rubber ( similar to the rubber in a windshield wiper blade ) and is used to keep oil from leaking past a moving part such as a spinning shaft.In some cases,the rubber is assisted by a spring that holds he rubber in close contact with the spinning shaft.
A gasket is a type of seal used to seal two stationary parts that are fasted together.Some common gasket materials are : paper,cork,rubber,silicone and soft metal.
Aside from the main seals,there are also a number of other seals and gasket that vary from transmission to transmission.A common example is the rubber O-ring that seals the shaft for the shift control lever.This is the shaft that you move when you manipulate the gear shifter.Another example that is common to most transmission is the oil pan gasket.In fact,seals are required anywhere that a device needs to pass through the transmission case with each one being a potential source for leaks.
9)Computer Controls
The computer uses sensors on the engine and transmission to detect such things as throttle position,vehicle speed,engine speed,engine load,stop light switch position,etc.to control exact shift points as well as how soft or firm the shift should be.Some computerized transmission even learn your driving style and constantly adapt to it so that every shift is timed precisely when you would need it.
Because of computer controls,sports models are coming out with the ability to take manual control of the transmission as through it were a stick shift lever through a special gate,then tapping it in one direction or the other in order to up-shift at will.The computer monitors this activity to make sure that the driver dose not select a gear that could over speed the engine and damage it.
Another advantage to these “ smart” transmission is that they have a self diagnostic mode which can detect a problem early on and warn you with an indicator light on the dash.A technician can then plug test equipment in and retrieve a list of trouble codes that will help pinpoint where the problem is.
中文譯文
自動變速器
對于現(xiàn)代的汽車,自動變速器是一個復(fù)雜的組件,這種傳遞動力的方式,是液力變矩器充當離合器來連接發(fā)動機和變速器。
兩個基本類型的自動變速器基于該車輛是否是前驅(qū)動或后驅(qū)動。對發(fā)動機前置后驅(qū)動的汽車,變速器通常安裝在發(fā)動機后底盤中心與油門配合。變速器輸出軸連接到后橋,把發(fā)動機的動力傳遞到后輪,動力傳輸系統(tǒng)是直線的,從發(fā)動機,通過液力變矩器、變速器、傳動軸、最后直接到到達車輪。
對于發(fā)動機前置前輪驅(qū)動的汽車,變速器通常和差速器裝在一起。對于前驅(qū)動的汽車,變速器安裝在發(fā)動機一側(cè),前車軸直接連接到差速器上,把動力傳遞給前輪。在這個布置中,