588 重型自卸車設(shè)計(jì)(底盤設(shè)計(jì))（有cad圖）,588,重型自卸車設(shè)計(jì)(底盤設(shè)計(jì))（有cad圖）,重型,卸車,設(shè)計(jì),底盤,cad 大學(xué)畢業(yè)設(shè)計(jì)（論文）開題報(bào)告 （學(xué)生填表） 學(xué)院： 車輛與動力工程學(xué)院 2013年 4 月10 日 課題名稱 重型自卸汽車設(shè)計(jì)（底盤設(shè)計(jì)) 學(xué)生姓名 專業(yè)班級 課題類型 工程設(shè)計(jì) 指導(dǎo)教師 職稱 課題來源 結(jié)合生產(chǎn) 1. 設(shè)計(jì)（或研究）的依據(jù)與意義 從我國重型汽車發(fā)展來看，20世紀(jì)60年代至80年代是非常緩慢的。改革開放以后，通過走引進(jìn)和自主研發(fā)相結(jié)合的道路，我國汽車工業(yè)“缺重”的局面逐步得到改觀。但由于各方面因素的影響，重型汽車市場一直處于低迷徘徊的態(tài)勢。直至1998年之后，在中、輕型貨車市場一路下滑時，重型銷量卻有了可喜的回升。此后，在國家連續(xù)幾年加大投資，實(shí)行積極的財(cái)政政策等一系列宏觀調(diào)控措施的帶動下，重貨市場呈逐年走高態(tài)勢，并進(jìn)入全面發(fā)展時期，全局性增長成為目前重貨市場的顯著特性。從分車型的銷售態(tài)勢上看，重貨繼續(xù)保持去年以來的超高速增長，當(dāng)月銷量已經(jīng)超過中型載貨車，成為一個歷史的轉(zhuǎn)折點(diǎn)。 隨著國內(nèi)基礎(chǔ)設(shè)施建設(shè)需要的不斷增加，自卸車產(chǎn)量近年來一直保持較高產(chǎn)銷量，在專用車綜合產(chǎn)量中保持第一位置，但在種類、型式、材料運(yùn)用方面與國外還有一定的差距。自卸車的快速增長主要原因是固定資產(chǎn)投資強(qiáng)勁增長，巨大的投資規(guī)模奠定了自卸車市場需求基礎(chǔ)；自卸車品種增加，不僅適應(yīng)和滿足施工需求，同時向運(yùn)輸市場發(fā)展；國家經(jīng)濟(jì)的快速發(fā)展，帶動了相關(guān)行業(yè)的快速發(fā)展，巨大的資源消耗，成為我國重型車和重型專用車發(fā)展的原動力。 我國重型汽車市場繼續(xù)保持著高速發(fā)展的狀態(tài)，重型汽車市場發(fā)展速度大大超過其他車型的增長速度。目前，市場強(qiáng)勁的增長勢頭尚未減弱跡象。 促進(jìn)重型汽車市場的主要原因； 1. 積極的財(cái)政政策繼續(xù)為國民經(jīng)濟(jì)發(fā)展提供了寬松的財(cái)政金融環(huán)境，融資和信貸更加便利，擴(kuò)大了人們的資金來源。 2. 國民經(jīng)濟(jì)保持了較高的發(fā)展速度，去年前6個月達(dá)到9.6%，公路運(yùn)輸業(yè)快速發(fā)展，西部大開發(fā)，基礎(chǔ)設(shè)施建設(shè)，房產(chǎn)業(yè)的繁榮進(jìn)一步擴(kuò)大了對重型汽車的需求。 3. 治理超限超載運(yùn)輸和嚴(yán)厲打擊走私，取締非法拼裝車的政策措施促進(jìn)了重型汽車市場的健康發(fā)展。 4. 主要重型汽車生產(chǎn)企業(yè)以市為導(dǎo)向，開發(fā)出一批適銷對路的產(chǎn)品，帶動了重型汽車市場的快速發(fā)展。 綜上：大力發(fā)展重型自卸車產(chǎn)業(yè)，搶先發(fā)展重型自卸汽車能為公司及行業(yè)發(fā)展贏得好的效益和發(fā)展先機(jī)。 2. 國內(nèi)外同類設(shè)計(jì)（或同類研究）的概況綜述 底盤作用是支承、安裝汽車及其各部件、總成，形成汽車的整體造型，并接受發(fā)動機(jī)的動力，是汽車產(chǎn)生運(yùn)動，保證其正常行駛。重型自卸汽車的技術(shù)含量主要體現(xiàn)在底盤的技術(shù)上，車輛的動力性能、操縱性能、安全性以至于可靠性等技術(shù)性能的優(yōu)劣，都毫無例外地取決于其底盤各總成、各主要結(jié)構(gòu)要素的性能及其合理的配置選擇。底盤設(shè)計(jì)得好壞對汽車的整車性能有著至關(guān)重要的影響。 國外的重型自卸汽車底盤技術(shù)走在了行業(yè)的前沿，無論是四個系統(tǒng)的總體布置，還是具體到每個總成設(shè)計(jì)都有一個成熟的開發(fā)，以及如何降低底盤的重量和耗材和功能實(shí)現(xiàn)最大化方面等都有一套先進(jìn)的理論。國外重型自卸汽車幾乎全部用柴油發(fā)動機(jī)作為動力，近年來天然氣、液化石油氣等清潔燃料發(fā)動機(jī)也取得了較快的發(fā)展。國外重型自卸汽車大多采用手動變速器 (由液力耦合器、變扭器與行星齒輪組成，或采用電腦程控的自動變速器)，主要是為了減輕駕駛員的勞動強(qiáng)度，增強(qiáng)汽車啟動和變速時的平順性。底盤制動系統(tǒng)多為前后鼓式，除了采用雙管路制動外，ABS、渦流緩速器、制動蹄自動調(diào)隙裝置等均屬于標(biāo)準(zhǔn)配置。 國內(nèi)的重型自卸汽車底盤總布置則比較落后，基本上是借鑒國外已有的技術(shù)。 目前國內(nèi)生產(chǎn)的各類重型自卸汽車中，80%以上是在普通載貨車底盤的基礎(chǔ)上改裝而成的。國內(nèi)基本上沒有一家專業(yè)生產(chǎn)專用汽車底盤的企業(yè)，這一現(xiàn)狀已經(jīng)極大地制約了我國重型自卸汽車的發(fā)展。因此國內(nèi)重型自卸汽車廠對于這一現(xiàn)象應(yīng)給予充分重視，要專門開發(fā)適應(yīng)市場需求的重型自卸汽車底盤。如何研制滿足用戶及市場需求的重型自卸車底盤，應(yīng)從以下幾方面考慮： 第一，與重型自卸車廠家進(jìn)行改裝方面的技術(shù)交流，了解上裝部分的專用性能要求、技術(shù)要求，開發(fā)滿足專用要求的底盤。 第二，充分了解重型自卸車使用環(huán)境及工況，對某些部件進(jìn)行相應(yīng)改進(jìn)，以適應(yīng)特定的環(huán)境及工況。 第三，召集行業(yè)內(nèi)有影響力的重型自卸車企業(yè)及用戶進(jìn)行技術(shù)交流，廣泛聽取各方面的意見及要求，開發(fā)或不斷改進(jìn)重型自卸車底盤。 第四，密切關(guān)注發(fā)達(dá)國家重型自卸車的發(fā)展動向，結(jié)合國際、國內(nèi)市場的需求趨勢，開發(fā)高技術(shù)、高附加值重型自卸汽車底盤，填補(bǔ)國內(nèi)空白并搶占國際市場。 3. 課題設(shè)計(jì)（或研究）的內(nèi)容 1. 重型自卸汽車總體布置設(shè)計(jì)，全組確定總體方案，并進(jìn)行討論，分析方案的可行性，（設(shè)計(jì)計(jì)算）繪制裝配圖以及主要的零部件工作圖。 2. 根據(jù)之前的計(jì)算進(jìn)行校核，并結(jié)合所繪制的圖紙，參閱相關(guān)文獻(xiàn)資料，撰寫設(shè)計(jì)說明書。 3. 完成外文翻譯 4. 設(shè)計(jì)（或研究）方法 1. 調(diào)研，搜集、分析資料，確立并論證方案； 2. 類比法，參照同類車型，初選總體布置設(shè)計(jì)基本參數(shù)； 3. 實(shí)物參觀，測量； 4. 對可行性方案進(jìn)行理論計(jì)算。校核設(shè)計(jì)零件，使設(shè)計(jì)滿足使用要求； 5. 計(jì)算機(jī)輔助設(shè)計(jì)，繪制主要零部件圖紙?jiān)O(shè)計(jì)。 5. 實(shí)施計(jì)劃 2周 調(diào)研，搜集、分析資料，明確具體任務(wù)，制定方案，撰寫開題報(bào)告。 2周 完成整車動力性和經(jīng)濟(jì)性計(jì)算，底盤布置總圖。 4周 完成底盤總圖及零、部件圖設(shè)計(jì)。 2周 編寫設(shè)計(jì)說明書和翻譯。星期五最后交卷。 1周 審核、互審評閱。 1周 答辯，評定成績。 指導(dǎo)教師意見 指導(dǎo)教師簽字： 年 月 日 教研室意見 教研室主任簽字： 年 月 日 車輛與動力工程學(xué)院畢業(yè)設(shè)計(jì)說明書 重型自卸車設(shè)計(jì)（底盤設(shè)計(jì)） 摘要 此次設(shè)計(jì)的非公路自卸車適應(yīng)于多種特定用途，是土方運(yùn)輸和各種露天礦剝巖、沙土運(yùn)輸?shù)慕?jīng)濟(jì)、高效、低耗的運(yùn)輸設(shè)備。該車具有為適應(yīng)重載工況而特殊設(shè)計(jì)的懸掛系統(tǒng)、加強(qiáng)型寬體驅(qū)動橋、14.00-24型寬大工程輪胎，使該車具有超強(qiáng)承載能力，同時提供了超強(qiáng)的附著能力，保證了車輛的制動穩(wěn)定性和良好的通過性，采用了大速比工程驅(qū)動橋，其輸出轉(zhuǎn)矩比同功率公路車大30%以上，爬坡能力強(qiáng)勁，重載起步順暢。 本說明書主要是對KD6400整車總體布置做了一個詳細(xì)的說明，其中包括整車主要尺寸（長*寬*高），前后軸距，輪距，軸荷分配的選擇和計(jì)算以及各總成（發(fā)動機(jī)，傳動系）的主要參數(shù)的選擇。 特別對整車的動力性和經(jīng)濟(jì)性做了比較全面而細(xì)致的分析和計(jì)算，對動力性分析時，分別作出了驅(qū)動力—行駛阻力平衡圖，動力特性圖，功率平衡圖。求出汽車的最大速度，另外也對汽車在不同的路面上行駛時，分別計(jì)算出了其最大爬坡度，并根據(jù)加速度倒數(shù)曲線求出汽車的加速時間，估算了該車的加速性能。在計(jì)算汽車的經(jīng)濟(jì)性時，根據(jù)發(fā)動機(jī)萬有特性曲線，作出了9擋時的燃油消耗曲線，同時計(jì)算得整車的百公里燃油消耗量。通過計(jì)算結(jié)果顯示，此汽車在動力性和經(jīng)濟(jì)性方面滿足了設(shè)計(jì)任務(wù)書的要求。 另外本文也對汽車的穩(wěn)定性和最小轉(zhuǎn)彎半徑做了計(jì)算和分析，并根據(jù)經(jīng)驗(yàn)估算出了空載和滿載時汽車的質(zhì)心位置以及軸荷分配。 關(guān)鍵詞：承載能力，附著能力，制動穩(wěn)定性，通過性，動力性，經(jīng)濟(jì)性 V DESIGN OF HEAVE –DUTY DUMP (CHASSIS DESIGN) ABSTRAC The non –highway heavy-duty dump truck of this design can adapt many kinds of given purpose.It is an economical,efficient and low useful conveyance for hillock transport,sand transport and all kind of outdoor mineral.It has especially desingned suspension system,strengthen widen project driving axle and 14-24type big wide project tales,this cause the truck possess preeminent bearing,at the same time ,this kind of tale can cause big climbing force,assuring the truck has brake stability and good transition.It is counted high rate riving axle,its output torque is 30 point bigger than the road vehicle which are at the same power. This book mainly give an expatiation about the vehicle general layout of the heavy dumper KD6400,including the vehicle dimensions(long*wide*high),the distribution of axle load in front and back ,the choice and calculation about the main parameter of the vehicle’s main components(engine,transmission)and so on. Especially in the dynamic property and economic performance,we give an overall and meticulo us analysis and calculation .In the dynamic property ,we made the driving force-road resistance equilibrium diagram,the dynamic factor diagram and the power balance diagram.From those diagram,we can get the maximum speed.We also calculated the maximum grade ability at different road ,according the acceleration curve:we can get the accelerating ability.According to the engine-cross sectional characteristic diagram,we made the fule consumption of 100km. In fact,the vehicle’s main parameters all come to the misson book ‘request. Morever ,we made an anlysis and calculation of the stability and minimum turning radius and estimated the distribution of axle load when there is no load and full load and the position of the vehicle’s center of mass. Key words:carrying capacity, adhesive ability, braking stability, trafficability characteristic, power performance, economical efficiency. 目 錄 第一章 前言………………………………………………………………………………...1 第二章 參考車型技術(shù)數(shù)據(jù)……………………………………………………………...3 第三章 汽車主要技術(shù)參數(shù)的確定…………………………………………………….4 §3.1 汽車主要尺寸的確定……………………………………………………………...4 §3.2 汽車質(zhì)量參數(shù)的確定……………………………………………………………...5 §3.3 發(fā)動機(jī)主要參數(shù)…………………………………………………………………...6 §3.4 輪胎的選擇………………………………………………………………………...7 §3.5 傳動比的選取……………………………………………………………………...7 §3.6 最大傳動比的選取…………………………………………………………….......8 §3.7 變速器各擋傳動比………………………………………………………………...9 第四章 軸荷分配及質(zhì)心位置的計(jì)算………………………………………………..10 §4.1 水平靜止時的軸荷分配及質(zhì)心位置的計(jì)算……………………………………..10 §4.2 汽車行駛時的軸荷分配的計(jì)算…………………………………………………..12 §4.3 汽車制動時的軸荷分配的計(jì)算………………………………………………….13 第五章 穩(wěn)定性計(jì)算…………………………………………………………..14 §5.1 縱向穩(wěn)定性……………………………………………………………………….14 §5.2 橫向穩(wěn)定性……………………………………………………………………….14 §5.3 最小轉(zhuǎn)彎半徑的計(jì)算…………………………………………………………….14 §5.4 在橫向坡上轉(zhuǎn)向時的穩(wěn)定性…………………………………………………….15 第六章 汽車動力性計(jì)算…………………………………………………………….....16 §6.1 汽車各擋速度的計(jì)算……………………………………………………………16 §6.2 汽車各擋驅(qū)動力的計(jì)算…………………………………………………………16 §6.3 汽車空氣阻力的計(jì)算……………………………………………………………17 §6.4 滾動阻力系數(shù)的計(jì)算……………………………………………………………18 §6.5 汽車行駛時動力因數(shù)D的計(jì)算………………………………………………...19 §6.6 各擋牽引功率Pe的計(jì)算………………………………………………………..19 §6.7 阻力功率的計(jì)算…………………………………………………………………20 §6.8 汽車加速度的計(jì)算………………………………………………………………21 §6.9 加速度倒數(shù)的計(jì)算………………………………………………………………22 §6.10 汽車爬坡度的計(jì)算………………………………………………………………22 第七章 汽車的燃油經(jīng)濟(jì)性…………………………………………………………....24 第八章 結(jié)論………………………………………………………………………………26 參考文獻(xiàn)…………………………………………………………………………………..27 致謝………………………………………………………………………………………...28 The English Instruction Dump Truck A dump truck or production truck is a truck used for transporting loose material(such as sand,gravel or dirt)for construction.A typical dump truck is equipped with a hydraulically operated open-box bed hinged at the rear,the front of which can be lifted up to allow the contents to be deposited on the ground behind the truck at the site of delivery.In the UK the term applies to off-road construction plant only and the road vehicle is known as a tipper. A standard dump truck is a full truck chassis with a dump body mounted to the frame.The dump body is raised by a hydraulic ram mounted forward of the front bulkhead,between the truck cab(traction unit)and the dump body (semi-trailer).The tailgate can be configured to swing on hinges or it can be configured in the “High Lift Tailgate” format where in pneumatic rams lift the gate open and up above the dump body. A standard dump truck has one front axle and one or more rear axles which typically have dual wheels on each side.Common configuration for a standard dump truck include the six wheeler which has one rear axle,the ten wheeler with two rear axles and the tri-axle with three rear axles.These are mainly found in inner cities and in the Deep South. The short wheelbase of a standard dump truck makes it more maneuverable than the higher capacity semi-trailer dump trucks. Off-road dump trucks more closely resemble heavy construction equipment or engineering vehicles than they do highway dump trucks.They are used strictly off-road for mining and heavy dirt hauling jobs. The term ‘Dump’Truck is not generally used by the mining industry or by the manufactures that build these machines.The more appropriate US term for this strictly off road vehicle is ‘Haul’truck.The classification bottom and side for example,describing how the loaded material is discharged once loaded.In the case of the Haul truck illustrated,a Liebherr T 282B the load is discharged to the rear,designing this particular vehicle as an end dump.Bottom dump normally describes a trailer that discharges its load by opening two clam shell doors under the load space,in some examples several trailers(road train)are pulled by one truck mainly these are on road machines.The only remaining example of what is described as a unitized bottom dump coal hauler is manufactured by Kress Corporation.This large capacity truck is used for the transportation of coal from a loading device directly to a power station or bulk storage area. Many winter service vehicle units are based on dump trucks to allow the placement of ballast to weigh the truck down or to hold salt for spreading on the road. A semi end dump is a tractor-trailer combination where in the trailer itself contains the hydraulic hoist.A typical semi end dump has a 3-axle tractor pulling a 2-axle semi-trailer.The key advantage of a semi end dump is rapid unloading.A key disadvantage is that they are very unstable when raised in the dumping position limiting their use in many applications where the dumping location is uneven or off level. Both the tractor and the automobile are complex self-propelled machines consisting of separate interacting machanisms and units that can be combined into certain groups. The arrangement of the main component parts of the tractor is shown in Fig.2.Irrespective of particular design features,all tractors consist of engine,drive line,running gear,steering mechanism,working attachments and auxiliary equipment. The drive line comprise a set of mechanisms which transmit the torque developed by the engine to the driving wheels or tracks and change the driving torque both in magnitude and direction,The drive line includes the cluth,flexible coupling,transmission and rear axle. The cluth serves to disconnect the engine shaft from the transmission for a short period of time while the drivers is shifting gears and also to connect smoothly the flow of power from the engine to the driving wheels or tracks when starting the tractor from rest. The flexible coupling incorporates elastic elements allowing connecting the cluth shaft and the transmission drive shaft with a slight misalignment The transmission makes it possible to change the tractor by engaging different pairs of gears.With the direction of rotation of the engine shaft remaining the same,the transmission enables the tractor to be put in reverse. The rear-axle mechanisms increase the driving torque and transmit it to the driving wheel or tracks at right angles to the drive shaft.In most tractors,the rear also comprises brakes. In the wheeled tractor,as distinct from its crawler counterpart,the drive line includes the differential which enzbles the wheels to revolve with different speeds when making turns or running over ragged terrain at which time the lefthand and righthand wheels must travel different distance during one and the same time. The steering mechanism serves to change the direction of movement of the tractor by turing its front wheels of by varying the speed of one of the tracks. The working attachment of the tractor are used to utilize the useful power of the tractor engine for various farm tasks.They include the power take off shaft,drawbar,implement-attaching system and belt pulley. The tractor auxiliaries include the driver’s cab with a spring-mounted seat and heating and ventilation equipment,hood,lighting equipment,tell tales horns etc. The arrangement and purpose of the main component parts of the automobile are in principle the same as those of the wheeled tractor.In the automobile,the drive line,running gear,steering mechanism and brakeing system are referred to collectively as the chasis.The steering mechanism serves to change the direction of traveled the braking system to slow down the running speed of the automobile or to stop it. The auxiliaries of the automobile include winch,cab heating and ventilation equipment,hitch bar,etc. The automobile and its engine are controlled and the operation of their mechanisms monitored by means of controls and instrucments located in the cab fort of the driver’s seat. To start the engine and control its operation,use is made of throttle pedal,radiator shutter control handle,choke button,ignition/starter switch and throttle hand lever.The ignition/start switch is operated by a key which may be placed in one of the following four positions:central position-all current consumers are switched off:first position clockwise-ignition is switched on;first position counter clock wise it is possible to actuate the horn,windshield wiper and heater blower with the ignition circuit switched off. Before starting the engine,it is necessary to check the radiator coolant level,the engine crankcase oil level and the fule level in the fuel tank. To start a warm engine,place gear shift lever in neutral and switch on ignition and the starter motor by turning the ignition key clockwise as far as it will go. To start a cold engine,it is recommended to do the following.Pump up gasoline by using the fule pump hand primer,Close the carburetor choke by pulling chock button outward full distance,Place the gear shift lever in neutral.Disengage the floor,which will decrease drag on the engine and thus ease the operation of the starter motor for in this case the transmission gears will not revolve in thickensed oil during starting.Switch on ignition and the starter motor by turning the ignition key fully clockwise;limit the time the start motor is energized to 5 second.Once the engine has started,switch off the starter motor by releasing the ignition key,open the chock by pushing its button inward one-half its full stroke,increase some what the speed by slightly depressing accelerator pedal and then engage the clutch by releasing its pedal.An engine in good rapair usually can be easily started,if the engine has first or second attempt.In the case of a false start,wait at least 30 second before attempting another start.If the engine has failed to start after the third attempt,check the ignition and fule systems.If the trouble is with the start motor or if the battery is discharged,the engine can be cranked up by your hand.When cranking up ,don’t grasp the crank handle,but keep your fingers on its one side only,so that the hand may not get hurt if the wngine kicks back. Before starting the engine in low-temperature conditions,shut off the oil cooler,fill the cooling system with hot water and the engine crankcase with hot oil or use the starting preheated.Prior to turning on the ignition switch,close the radiator shutter by pulling handle out ward full distance and crank the engine three to five revolutions with the crank handle.Then perform all the rest operations as recommended for starting the cold engine. Automobile controls include clutch pedal,brake pedal,throttle pedal,steering wheel,gear shift lever and parking brake lever. Before starting to drive,warm up the engine at a moderate speed until the coolant temperature reachs 60℃.As the engine gets warmer,gradually open the choke and decrease the engine speed with the choke fully open.Read the dashboard instruments to check on the operation of the engine. To monitor the operation of engine and the automobile itself,use is made of the following instruments and indicator mounted on the instrument panel in front of the driver’s seat:temperature gauge and temperature warning lamp and oil pressure gauge. Signaling is effected by means of horn button and turn signal switch handle downwards causes the left-hand side of the steering column.Turning the directional signal switch handle downwards causes the left-hand side and tail lights to flash,thus gibing indication of a left turn and turning it upwards actuates the right-hand side and tail lights to indicate a right turns.Whenever either of the turn signal light is switch on turn signal indicator lamp on the instrucment panel starts flashing.The turn signal lights are switched off automatically when the automobile is straightened after turning. On the left-hand side of the cab floor there is dimmer switch which is used to switch over the head lights from high to low beam and vice versa.Main light switch has three position:1.all lights are off;2.side lights,license plate light,tail maker lights and instrument panel light are switched on;3.side lights,head lights,tail mark lights,instrument panel light and license plate light and license plate lights are switched on. Mounted on the instrument panel are windshield wiper and heater blower switches blower are switched on by turning their respective switches clockwise.The wiper switch has three positions;off,slow and fast.That of the heater blower also has three position:off ,low air delivery and high air delivery. Mounted under the instrucment panel are radiation shutter control handle and hood catch handle.Pulling back on handle will close the radiator shutter and pulling back on handle will release the hood catch.There are also two circuits.Breaker button,cowl ventilator handle and ventilator air intake control handle.With handle in the extreme left-hand position,the cowl ventilator is fully open and with the handle in the extreme right-hand position,the air intake door is fully open and when the handle is in the extreme right-hand position,it is fully closed. 1．The last component in the drive train is the axle in a rear wheel drive car axle is in the rear.Engine power is transmitted from the transmission to the axle via the drive shaft.The drive shaft is basically a metal tuber with joints on each end called universal joints.These joints allow the tube to move in relation to the suspension and keep powers flowing to the real.In front wheel drive cars the axle is integrated into the transmission thus the term transaxle. 2. The drive shaft or propeller shaft,connects the transmission output shaft to the differential pinion shaft.Since all roads are not perfectly smooth and the transmission is fixed,the drive shaft has to be flexible to absorb the shock of bumps on the road.Universal or “U-joints”allow the drive shaft to flex(and stop it from breaking)when the drive angle changes. 3. Drive shafts are usually hollow in order to weigh less,but of a large diameter so that they are strong.High quality steel and sometimes aluminum are used in the manufacture of the drive shaft.The shaft must be quite straight and balanced to avoid vibrating.Since it usually turns at engine speeds,a lot of damage can be caused if the shaft is unbalanaced or bent.Damage can also be caused if the U-joints are worn out. Most power steering systems work by using a hydraulic system to rotate the vehicle’s wheel.The hydraulic pressure is usually provided by a gerotor or rotary vane pump driven by the vehicle’s engine.A double-acting hydraulic cylinder applies a force to the steering mechanism,which in turn applies a torque to the wheels.The flow to the cylinder is countrolled by valves by the steering wheel.There are several common valve.This is done so that the position of the steering wheel corresponds to the position of the vehicle’s wheels.As the pumps employed are of the positive displacement type,the flow rate they deliver is directly proportional to the speed of the engine. This means that at high engine speeds the steering would naturally operate faster than at low engine speeds .Because this would be undersirable,a restricting orifice and flow control valve are used to direct some of the pump’s output back to the hydraulic reservoir at high engine speeds.A pressure when the hydraulic cylinder’s piston reaches the end of the cylinder. Some modern implementations also include an electronic pressure relief valve which can reduce the hydraulic pressure in the power steering lines as the vehicle’s speed increase(this is known as variable assist power steering). 英文翻譯 自卸汽車 一輛自卸車或者生產(chǎn)用自卸車是用來運(yùn)輸建筑用的散料（例如：沙、礫石和垃圾）的汽車。專用自卸車要求后面有液壓傾斜的貨箱，它的前部可以被舉起讓貨物堆放在送貨的汽車后面。在英國，這種汽車只允許在非公路場地用，并且公路車被認(rèn)為是自卸車。 標(biāo)準(zhǔn)自卸車是在車架上安裝了自卸車箱的整車底盤。車廂被安裝在艙壁前面的液壓缸舉起，液壓缸位于駕駛室（牽引單元）和車廂（掛車）之間。標(biāo)準(zhǔn)的自卸車有一個前橋、一個或者更多每邊都有雙后輪的典型后橋，兩個后橋十個車輪，并且四車軸有三個后橋。這些主要在中部城市和南方見到。 短軸距的標(biāo)準(zhǔn)自卸車比更高的儲存容量半掛車自卸車更具機(jī)動性。 非公路自卸車比公路用車更接近與建設(shè)設(shè)備或工程汽車。它們被嚴(yán)格要求運(yùn)用于采礦和非公路的重型場合。 自卸車并不經(jīng)常被用于采礦業(yè)和建筑業(yè)。在大部分的美國，這種嚴(yán)格意義上的非公路汽車是轉(zhuǎn)運(yùn)卡車，例如它典型的地步和側(cè)面，介紹了當(dāng)被裝上后的材料是如何被卸載的。在轉(zhuǎn)運(yùn)卡車的車廂的說明里，利勃海爾T282b貨車貨物時卸載到后方的，指定這個特別的車輛作為年轉(zhuǎn)運(yùn)卡車。有一些例子，幾個拖車（公路列車）是由一輛在道路上行走的卡車牽引。剩下的唯一的例子是被形容為組合煤車hauler是由kress公司制造的。這個大容量的卡車是用來從一個加載裝置直接向電力站或散裝儲存區(qū)運(yùn)輸煤炭的。 許多冬季服務(wù)車輛單位的基礎(chǔ)是自卸卡車，通過布置壓載物來增加卡車的重量或?qū)Ⅺ}散布在道路上。 一個半掛自卸車是一個拖拉機(jī)與掛車的組合，其中拖車本身包含液壓啟閉機(jī)。一個典型的半掛自卸車有一個3軸拖拉機(jī)牽引2軸半掛車。關(guān)鍵的優(yōu)勢是一個半掛自卸車可快速的卸載。一個關(guān)鍵的缺點(diǎn)是它們在傾卸貨物時很不穩(wěn)定，這限制了它在許多場合的應(yīng)用，如傾卸的場地是不平的。 拖拉機(jī)和汽車都是復(fù)雜的自動行走機(jī)器，它由不同的相互作用的機(jī)械裝置和設(shè)備組成，從而形成一定的組合，拖拉機(jī)主要由以下部分組成，不考慮專門的設(shè)計(jì)特征，所有的拖拉機(jī)是由發(fā)動機(jī)，驅(qū)動機(jī)構(gòu)，汽車傳動，轉(zhuǎn)向和懸架裝置機(jī)構(gòu)，轉(zhuǎn)向裝置，工作附件，輔助設(shè)備。 發(fā)動機(jī)使熱能轉(zhuǎn)變?yōu)闄C(jī)械能。 驅(qū)動機(jī)構(gòu)由一套機(jī)械裝置組成，它們能傳遞由發(fā)動機(jī)曲軸輸出的扭矩并能在大小和方向上改變轉(zhuǎn)動扭矩。驅(qū)動機(jī)構(gòu)包括離合器、柔性連機(jī)器、變速器和后輪軸。 離合器的作用是使當(dāng)司機(jī)換擋時使發(fā)動機(jī)曲軸短時間內(nèi)脫離變速器，同時也是在啟動拖拉機(jī)是自如的將能量從發(fā)動機(jī)傳到驅(qū)動輪上。 柔性聯(lián)軸節(jié)把彈性元件離合器軸和功率傳動軸連接在一起，并允許它們有輕微的同軸度。 變速器通過嚙合多對齒輪來改變驅(qū)動扭矩和拖拉機(jī)的行駛速度，為了發(fā)動機(jī)曲軸方向自動保持一致，變速器能幫助拖拉機(jī)倒車。后輪裝置可以提高行駛扭矩并能以合適的角度改變扭矩，在大多數(shù)的拖拉機(jī)中，后驅(qū)動橋由制動器組成，高速拖拉機(jī)與低速拖拉機(jī)的區(qū)別是驅(qū)動機(jī)構(gòu)，包括差速器，能使車輪在轉(zhuǎn)彎時或崎嶇的山路上以不同的角速度轉(zhuǎn)動。在一定的時間或相同的時間內(nèi)左右車輪可以行駛不同的距離。 汽車的運(yùn)轉(zhuǎn)，轉(zhuǎn)向和懸架機(jī)構(gòu)是拖拉機(jī)行走的需要，車輪的轉(zhuǎn)動與地面有關(guān)。 轉(zhuǎn)向裝置用于通過轉(zhuǎn)變前輪或改變速度從而改變拖拉機(jī)的轉(zhuǎn)動方向。 工作附件是利用拖拉機(jī)的發(fā)動機(jī)的可用能量來完成不同的農(nóng)業(yè)工作，它們包括動力輸出軸、拉桿、推動裝置和皮帶輪。 拖拉機(jī)的輔助系統(tǒng)包括駕駛室的彈性座椅和加熱通風(fēng)裝置、發(fā)動機(jī)罩、點(diǎn)火裝置、方向指示器、喇叭等。 汽車主要組成部分的布置和目的在理論上與轉(zhuǎn)動拖拉機(jī)的安排在道理上是一樣的，在汽車上，汽車的傳動機(jī)構(gòu)，驅(qū)動機(jī)構(gòu)，汽車的傳動，轉(zhuǎn)向，懸架機(jī)構(gòu)是用于改變行駛和制動的方向，放慢行駛中的汽車速度直至汽車停下為止。 汽車的輔助裝置包括絞車盤，駕駛室、加熱和通風(fēng)裝置、牽引桿等。 汽車的控制汽車和它的發(fā)動機(jī)的控制和對這些裝置的操作受到駕駛室前面的一些控制件和部件的監(jiān)控。 為了啟動發(fā)動機(jī)并控制其旋轉(zhuǎn)，需要用節(jié)流操作踏板、散熱器百葉窗控制手柄、阻風(fēng)門按鈕、點(diǎn)火開關(guān)和節(jié)氣門操縱拉桿。點(diǎn)火開關(guān)由位于以下四個位置的任何一個開關(guān)，中間位置——所有的電流消耗被關(guān)閉，第一個位置也是點(diǎn)火開關(guān)，同樣第二個位置可以打開點(diǎn)火開關(guān)和開啟電動機(jī)，第一個開關(guān)可以按響小喇叭，擦擋風(fēng)玻璃，同時關(guān)閉加熱器和鼓風(fēng)機(jī)的加熱系統(tǒng)。 在啟動發(fā)動機(jī)前，有必要檢查指示器里油液的多少，發(fā)動機(jī)曲軸箱機(jī)油的多少和燃油箱里燃油的多少。 要啟動一個熱的發(fā)動機(jī)請把換擋桿至于中間的位置，并打開點(diǎn)火開關(guān)，并啟動氣動馬達(dá)以使發(fā)動機(jī)運(yùn)轉(zhuǎn)起來。 要啟動一臺冷的發(fā)動機(jī)，建議按如下操作進(jìn)行：通過啟動液壓泵提高汽油壓力，把阻風(fēng)門按鈕撥到關(guān)閉阻風(fēng)門，把換擋桿置中，通過踩離合器，將離合器踩至駕駛室地面，這樣就可以減小離合器的阻力，從而以便于啟動發(fā)動機(jī)，因?yàn)樵谶@種情況下，變速器不會在變濃的機(jī)油里攪動。打開點(diǎn)火開關(guān)，啟動電動機(jī)和發(fā)動機(jī)，限制啟動發(fā)動機(jī)的時間持續(xù)五秒,如果發(fā)動機(jī)被開啟，通過松開點(diǎn)火開關(guān)即可關(guān)閉發(fā)動機(jī)，通過推阻風(fēng)門按鈕打開阻風(fēng)門，輕輕踩下加速器踏板在一定程度上能加快發(fā)動機(jī)的轉(zhuǎn)速，同時逐漸放開離合器踏板時離合器結(jié)合。一臺狀態(tài)良好的發(fā)動機(jī)在一兩次的嘗試下很容易就能啟動。如果啟動失敗，請?jiān)诹硪淮螁忧爸辽俚却?0秒。如果再試一次仍然無法啟動，請檢查點(diǎn)火裝置和供油系統(tǒng)，如果問題出現(xiàn)在啟動器或電池組上，可以采用手柄的一邊，這樣如果發(fā)動機(jī)反轉(zhuǎn)就不會受傷。 在低溫狀態(tài)下，啟動發(fā)動機(jī)前請關(guān)閉冷卻器，用熱水灌滿冷卻裝置是發(fā)動機(jī)機(jī)油箱充滿熱的機(jī)油或者使用啟動預(yù)熱裝置，在打開點(diǎn)火開關(guān)之前請關(guān)閉散熱器百葉窗，然后按以下建議打開其余的裝置。 汽車的控制包括離合器踏板、制動器踏板、節(jié)流操作踏板、方向盤、換擋桿和駐車制動桿。 在開始駕駛之前，請以適當(dāng)?shù)霓D(zhuǎn)速加熱發(fā)動機(jī)直至冷卻液溫度達(dá)到60℃，隨著發(fā)動機(jī)的變熱，隨著阻風(fēng)門的全部打開，逐步打開阻風(fēng)門并降低發(fā)動機(jī)的轉(zhuǎn)速，請閱讀儀表盤儀器以檢測發(fā)動機(jī)的運(yùn)行情況。 為了檢測發(fā)動機(jī)的運(yùn)轉(zhuǎn)和汽車自身，常使用被安裝在駕駛員座椅前儀表板上的設(shè)備和儀表:溫度計(jì)、溫度警告燈、燃油油量計(jì)、速度計(jì)、燃油壓力警告燈、電流表、燃油壓力計(jì)。 信號是由撥動開關(guān)和安裝在轉(zhuǎn)向柱左邊的信號開關(guān)產(chǎn)生的。向下轉(zhuǎn)動轉(zhuǎn)向信號開關(guān)左轉(zhuǎn)向燈和車后燈就閃爍起來，這樣指示將要向左轉(zhuǎn)彎。并且向上轉(zhuǎn)動使得右邊的燈和車后燈指示右轉(zhuǎn)彎，不管任何時候開啟任何一個轉(zhuǎn)向信號燈，安裝在儀表板上的轉(zhuǎn)向信號指示燈都將閃爍。當(dāng)汽車轉(zhuǎn)彎后直線行駛時轉(zhuǎn)向信號燈自動關(guān)閉。 在汽車地板的左邊有腳dimmer開關(guān)，它是用來從高到底開啟頂部的燈beam and vice versa 主燈開關(guān)有三個位置：1.所以的燈都關(guān) 2.邊燈、方向盤燈、后車標(biāo)燈和儀表板燈都亮 3.邊燈、頭頂燈、后車標(biāo)燈、儀表盤燈和駕駛方向盤燈都滅。 安裝在儀表盤上的擋風(fēng)玻璃雨刮器和除霜吹風(fēng)機(jī)開關(guān)都可以通過順時針撥動各自的開關(guān)來開啟。雨刮器開關(guān)有三個位置：關(guān)、小流量、和大流量。 安裝在儀表盤下面的是散熱器百葉窗開關(guān)控制手柄和車篷手柄。往后拉動手柄可以關(guān)上散熱器百葉窗，拉回手柄可以釋放車篷。它們同樣有兩條回路。當(dāng)手柄到達(dá)左邊最大位置時進(jìn)氣通風(fēng)口全開，到達(dá)右邊最大位置時全閉。當(dāng)手柄在左邊最大位置時進(jìn)氣是全開的，當(dāng)手柄在右邊最大位置時進(jìn)氣門全閉。 1. 在后輪驅(qū)動的汽車上傳動系的最后部件是后驅(qū)動橋。發(fā)動機(jī)功率傳遞，通過傳動軸從變速器傳輸?shù)胶髽?。該傳動軸基本上是一個兩端都有萬向節(jié)的金屬管。這些萬向節(jié)，使金屬管可以和懸架隨動和保持轉(zhuǎn)矩不斷地流向后橋。在前輪驅(qū)動的汽車中傳動軸被集成到了變速器，這樣組成了傳動系。 2. 傳動軸或萬向傳動軸，連接變速器輸出軸到差速器輸入軸。因?yàn)樗械牡缆范疾荒芡耆巾?，并且變速器是固定的，傳動軸必須做成彈性的以吸收坎坷道路引起的震動。一般，當(dāng)傳動角變化時“u型接頭”允許傳動軸彎曲。 3. 傳動軸通常是中空的，目的是減輕重量，但一個大的直徑，以便他們有足夠的強(qiáng)度。高優(yōu)質(zhì)鋼，有時候鋁都可以用于制造傳動軸。傳動軸必須有很高的直線度和動平衡度，以避免震動。因?yàn)樗ǔＪ禽喠髟诎l(fā)動機(jī)速度，如果軸不平衡或彎曲，都可以引起很多的危害，如果u型連接已磨損將引起危害。 大多數(shù)的動力轉(zhuǎn)向系統(tǒng)是用液壓系統(tǒng)來轉(zhuǎn)動汽車的輪子的。油液壓力通常由一個由發(fā)動機(jī)驅(qū)動的活塞泵或者旋轉(zhuǎn)葉片泵來提供。一個雙向液壓活塞向轉(zhuǎn)向機(jī)構(gòu)提供壓力，轉(zhuǎn)向機(jī)構(gòu)輪流向車輪提供轉(zhuǎn)矩。液體的流量由方向盤操作來控制。有幾種普通閥雖然較復(fù)雜，但是它們都允許轉(zhuǎn)向輪轉(zhuǎn)動比開啟一個簡單的必要的閥容易。這樣可以使轉(zhuǎn)向輪的位置對應(yīng)汽車車輪的位置。隨著泵的作用輪胎發(fā)生位移，流量直接正比于發(fā)動機(jī)的轉(zhuǎn)速。這就意味著在發(fā)動機(jī)高速時需要一個限流閥和流量控制閥被用來引導(dǎo)一部分泵的輸出返回到油液泵。一個泄壓閥也被用來防止當(dāng)液壓缸活塞到達(dá)活塞缸頂部室所建立的壓力引起的危險。 一些現(xiàn)代的調(diào)壓閥也包含一個電子泄壓閥，這個電子泄壓閥可以減小動力轉(zhuǎn)向系在發(fā)動機(jī)轉(zhuǎn)速上升時油液的壓力（這就是我們眾所周知的可調(diào)式動力轉(zhuǎn)向）。 11