高位剪式自卸車設(shè)計（全套含CAD圖紙）

高位剪式自卸車設(shè)計（全套含CAD圖紙）,高位,卸車,設(shè)計,全套,cad,圖紙 本科生畢業(yè)設(shè)計 (論文) 外 文 翻 譯 原 文 標 題 Hydraulic?System 譯 文 標 題 液壓系統(tǒng)? 作者所在系別 作者所在專業(yè) 作者所在班級 作 者 姓 名 作 者 學 號 指導教師姓名 指導教師職稱 完 成 時 間 2017 年 3 月 譯文標題 液壓系統(tǒng) 原文標題 Hydraulic?System 作 者 Frank L.Hale 譯 名 弗蘭克.L.赫爾 國 籍 美國 原文出處 龍源期刊網(wǎng)http://www.qikan.com.cn 譯文： 液壓系統(tǒng)? 一般僅有以下三種基本方法傳遞動力：電氣、機械和液壓。大多數(shù)應用系統(tǒng)實際上是將三種方法組合起來而得到最有效的最全面的系統(tǒng)。為了合理地確定采取哪種方法，重要的是了解各種方法的顯著特征。例如液壓系統(tǒng)在長距離上比機械系統(tǒng)更能經(jīng)濟地傳遞動力。然而液壓系統(tǒng)與電氣系相比，傳遞動力的距離較短。? 液壓傳動有許多突出的優(yōu)點，它被廣泛的應用，如一般工業(yè)用的塑料加工機械，壓力機械，機床等；應用機械設(shè)備工程機械，建筑機械，農(nóng)業(yè)機械，汽車等；鋼鐵行業(yè)的冶金機械，起重機械，還有軋輥調(diào)整裝置等；水利工程中的控制閘門裝置，河床升降裝置，橋梁和其他操作機構(gòu)；發(fā)電廠高速渦輪裝置，核電站等；船舶甲板用的起重機械（絞車），船頭門，艙壁閥、船尾推進器等；特殊技術(shù)用的巨型天線控制裝置、測量浮標、升降旋轉(zhuǎn)舞臺等；軍事工業(yè)用的火炮操縱裝置、船舶減搖裝置、飛行器仿真、飛機起落架的收放裝置和方向舵控制裝置等。特殊技術(shù)的天線控制裝置，測量浮標，升降旋轉(zhuǎn)舞臺；軍用的火炮操縱裝置，船舶減搖裝置，飛行器仿真，飛機起落架收放裝置和方向舵控制裝置和其他設(shè)備。? 液壓系統(tǒng)的作用為通過改變壓強增大作用力。一個液壓系統(tǒng)的好壞取決于系統(tǒng)設(shè)計的合理性、系統(tǒng)元件性能的優(yōu)劣，系統(tǒng)的污染防護和處理，而最后一點尤為重要。近年來我國國內(nèi)液壓技術(shù)有很大的提高，不再單純地使用國外的液壓技術(shù)進行加工。? 一個完整的液壓系統(tǒng)由五個部分組成，即動力元件、執(zhí)行元件、控制元件、輔助元件（附件）和液壓油。? 動力元件的作用是將原動機的機械能轉(zhuǎn)換成液體的壓力能，指液壓系統(tǒng)中的油泵，它向整個液壓系統(tǒng)提供動力。液壓泵的結(jié)構(gòu)形式一般有齒輪泵、葉片泵和柱塞泵。? 執(zhí)行元件(如液壓缸和液壓馬達)的作用是將液體的壓力能轉(zhuǎn)換為機械能，驅(qū)動負載作直線往復運動或回轉(zhuǎn)運動。? 控制元件(即各種液壓閥)在液壓系統(tǒng)中控制和調(diào)節(jié)液體的壓力、流量和方向。根據(jù)控制功能的不同，液壓閥可分為壓力控制閥、流量控制閥和方向控制閥。壓力控制閥又分為益流閥(安全閥)、減壓閥、順序閥、壓力繼電器等；流量控制閥包括節(jié)流閥、調(diào)整閥、分流集流閥等；方向控制閥包括單向閥、液控單向閥、梭閥、換向閥等。根據(jù)控制方式不同，液壓閥可分為開關(guān)式控制閥、定值控制閥和比例控制閥。? 輔助元件包括油箱、濾油器、油管及管接頭、密封圈、快換接頭、高壓球閥、膠管總成、測壓接頭、壓力表、油位油溫計等。 ? 液壓油是液壓系統(tǒng)中傳遞能量的工作介質(zhì)，有各種礦物油、乳化液和合成型液壓油等幾大類。? 液壓系統(tǒng)的作用是幫助人類工作，主要通過執(zhí)行元件將壓力轉(zhuǎn)換為旋轉(zhuǎn)或往復運動。?液壓原理：它由兩個不同大小的缸體充滿了水或油。充滿水的稱為“水壓機”，充滿油的稱為“液壓機”。兩個液缸每個都有一個可動的活塞，如果在小活塞上加點壓力，根據(jù)帕斯卡定律，小活塞的壓力通過液體的壓力傳遞到大活塞，頂端的活塞將前進很長的距離。基本小活塞的橫截面積為S1，外加一個小活塞上一個向下的力F1。因此，小活塞對液體的壓強P=F1/S1的，可以在所有方向上傳輸同樣大小。通過大活塞的壓力也為P。如果大活塞的橫截面積為S2，活塞的壓強P向上的壓力F2=P*S2，橫截面積是小活塞的幾倍，加給小活塞小的力，活塞會有大的壓力，由此用液壓機壓制膠合板，油，提起重物，鍛造煉鋼。? 液壓系統(tǒng)成功而又廣泛使用的秘密在于它的通用性和易操作性。液壓動力傳遞不會像機械系統(tǒng)那樣受到機器幾何形體的制約，另外，液壓系統(tǒng)不會像電氣系統(tǒng)那樣受到材料物理性能的制約，它對傳遞功率幾乎沒有量的限制。例如，一個電磁體的性能受到鋼的磁飽和極限的限制，相反，液壓系統(tǒng)的功率僅僅受材料強度的限制。? 企業(yè)為了提高生產(chǎn)率將越來越依靠自動化，這包括遠程和直接控制生產(chǎn)操作加工過程和材料處理等。液壓動力之所以成為自動化的重要組成部分，是因為它有如下主要的四種優(yōu)點：? 1?控制方便，精確通過操作一個簡單的操縱桿和按鈕，液壓系統(tǒng)的操作者便能立即起動、停止、加減速和能提供任意功率、位置精度為萬分之一英寸的位置控制力。一個使飛機駕駛員升起和落下起落架的液壓系統(tǒng)，當飛行員向某方向移動控制閥，壓力油流入液壓缸的某一腔從而降下起落架。飛行員向相反方向移動控制閥，允許油液進入液壓缸的另一腔來收起落架。? 2?增力，一個液壓系統(tǒng)沒有使用笨重的齒輪、滑輪杠桿就能簡單有效地將不到一盎司的力放大產(chǎn)生兒上百噸力的輸出。? 3?恒力或恒扭矩，只有液壓系統(tǒng)能提供不隨速度變化而變化的恒力或恒扭矩，它可以驅(qū)動對象從每小時移動幾英寸到每分鐘幾百英寸．從每小時幾轉(zhuǎn)到每分鐘幾千轉(zhuǎn)。? 4?簡便、安全、經(jīng)濟，總的來說，液壓系統(tǒng)比機械或電氣系統(tǒng)使用更少的運動部件，因此，它們運行與維護簡便。這使得系統(tǒng)結(jié)構(gòu)緊湊，安全可靠。例如一種用于車輛上的新型動力轉(zhuǎn)向控制裝置己淘汰其他類型的轉(zhuǎn)向動力裝置，該轉(zhuǎn)向部件中包含有人力操縱 方向控制閥和分配器。因為轉(zhuǎn)向部件是全液壓的，沒有萬向節(jié)、軸承、減速齒輪等機械連接，這使得系統(tǒng)簡單緊湊。另外，只需輸入很小的扭矩就能產(chǎn)生滿足極惡劣工作條件所需的控制力．這對操作空間限制而需要小方向盤的場合很重要，這也是減輕操作者疲勞所必需的。? 液壓系統(tǒng)的其他優(yōu)點包括雙向運動、過載保護和無級變速控制，在已有的任何動力系統(tǒng)中液壓系統(tǒng)亦具有最大的單位質(zhì)量功率比。? 液壓系統(tǒng)也有三個弱點：? 1?由于傳動介質(zhì)（液壓油）流動的過程中部分位置流速不同，導致液體內(nèi)部出現(xiàn)摩擦，同時液體與管道內(nèi)壁也有摩擦，這都是液壓油溫度升高的原因。溫度過高會導致更多的內(nèi)部和外部的泄漏，減少其機械效率。同時由于較高的溫度，液壓油會膨脹。導致可壓縮增大，使操作不能很好的控制傳輸。解決方法：高溫是液壓系統(tǒng)的自身問題，只能最大減輕不能根除。使用質(zhì)量更好的液壓油，液壓管的布局盡量避免出現(xiàn)彎曲，使用高品質(zhì)的管材和管件，液壓閥等。? 2?液壓系統(tǒng)的震動也是弱點之一。由于液壓油在管道中流動的高速沖擊和控制閥的打開關(guān)閉的過程中的影響是系統(tǒng)振動的原因。強烈震動會導致系統(tǒng)的控制動作錯誤，也會使系統(tǒng)中一些更復雜精密設(shè)備出現(xiàn)錯誤，從而導致系統(tǒng)故障。解決方案：液壓管應該是固定的，以避免急彎。為了避免頻繁流動方向的變化，無法避免時應將減震措施應該做到最好。整個液壓系統(tǒng)應具有良好的減振措施，同時避免在系統(tǒng)外部振蕩器的影響。? 3?液壓系統(tǒng)有內(nèi)泄露和外泄露，內(nèi)泄漏是指發(fā)生在系統(tǒng)中的泄露過程，如液壓活塞?-?缸的泄漏，控制閥滑閥與閥體之間的泄漏，如兩側(cè)。內(nèi)泄漏雖然沒有液壓油的損失，但是由于泄露，已經(jīng)確定的控制動作會受到影響，直至系統(tǒng)故障。外泄露是指發(fā)生在系統(tǒng)與外部環(huán)境之間的泄露。液壓油直接泄露到環(huán)境中，除了會影響工作環(huán)境，沒有足夠的動力將導致系統(tǒng)故障。液壓油泄露到環(huán)境中也有火災的危險。解決方案：使用質(zhì)量更好的密封件，以提高設(shè)備的加工精度。? 在液壓系統(tǒng)及其系統(tǒng)中，密封裝置用來防止工作介質(zhì)的泄漏及外界灰塵和異物的侵入。其中起密封作用的元件，即密封件。外漏會造成工作介質(zhì)的浪費，污染機器和環(huán)境，甚至引起機械操作失靈及設(shè)備人身事故。內(nèi)漏會引起液壓系統(tǒng)容積效率急劇下降，達不到所需要的工作壓力，甚至不能進行工作。侵入系統(tǒng)中的微小灰塵顆粒，會引起或加劇液壓元件摩擦副的磨損，進一步導致泄漏。? 因此，密封件和密封裝置是液壓設(shè)備的一個重要組成部分。它的工作的可靠性和使用壽命，是衡量液壓系統(tǒng)好壞的一個重要指標。除間隙密封外，都是利用密封件，使相鄰兩個偶合表面間的間隙控制在需要密封的液體能通過的最小間隙以下。在接觸式密封中，分為自封式壓緊型密封和自封式自緊型密封（即唇形密封）兩種。 原文： Hydraulic?System? There?are?only?three?basic?methods?of?transmitting?power：Electrical，mechanical．a(chǎn)nd?fluid?power．Most?applications?actually?use?a?combination?of?the?three?methods?to?obtain?the?most?efficient?overall?system．To?properly?determine?which?principle?method?to?use。it?is?important?to?know?the?salient?features?of?each?type．For?example，fluid?systems?call?transmit?power?more?economically?Over?greater?distances?than?Can?mechanical?types．However。fluid?systems?are?restricted?to?shorter?distances?than?are?electrical?systems．?? Hydraulic?transmission?there?are?many?outstanding?advantages,?it?is?widely?used,?such?as?general?industrial?use?of?plastics?processing?machinery,?the?pressure?of?machinery,?machine?tools,?etc.;?operating?machinery?engineering?machinery,?construction?machinery,?agricultural?machinery,?automobiles,?etc.;?iron?and?steel?industry?metallurgical?machinery,?lifting?equipment,?such?as?roller?adjustment?device;?civil?water?projects?with?flood?control?and?dam?gate?devices,?bed?lifts?installations,?bridges?and?other?manipulation?of?institutions;?speed?turbine?power?plant?installations,?nuclear?power?plants,?etc.;?ship?from?the?deck?heavy?machinery?(winch),?the?bow?doors,?bulkhead?valve,?stern?thruster,?etc.;?special?antenna?technology?giant?with?control?devices,?measurement?buoys,?movements?such?as?rotating?stage;?military-industrial?control?devices?used?in?artillery,?ship?anti-?rolling?devices,?aircraft?simulation,?aircraft?retractable?landing?gear?and?rudder?control?devices?and?other?devices.? The?role?of?the?hydraulic?system?to?increase?the?force?by?changing?the?pressure.?A?hydraulic?system?is?good?or?bad?depends?on?the?system?design?is?reasonable,?the?merits?of?the?performance?system?components,?system,?pollution?prevention?and?treatment,?while?the?last?point?is?particularly?important.?In?recent?years,?China's?domestic?hydraulic?technology?has?greatly?improved,?not?simply?using?hydraulic?technology?from?abroad?for?processing.? ?A?complete?hydraulic?system?consists?of?five?parts,?namely,?power?components,?the?implementation?of?components,?control?components,?auxiliary?components?(Annex)?and?the?hydraulic?oil.?? The?role?of?dynamic?components?is?the?original?motivation?of?the?mechanical?energy?into?fluid?pressure?energy,?the?hydraulic?system?of?pumps,?which?provide?power?to?the?entire?hydraulic?system.?Structures?of?hydraulic?pumps?generally?have?gear?pumps,?vane?pumps?and?piston?pumps. Implementation?of?components?(such?as?hydraulic?cylinders?and?hydraulic?motors)?is?to?pressure?the?liquid?can?be?converted?to?mechanical?energy?to?drive?the?load?for?a?linear?reciprocating?movement?or?rotational?movement.? Control?components?in?the?hydraulic?system?control?and?regulation?of?fluid?pressure,?flow?and?direction.?According?to?the?different?control?functions,?hydraulic?valves?can?be?divided?into?pressure?control?valves,?flow?control?valves?and?directional?control?valve.?Pressure?control?valve?is?divided?into?benefits?flow?valve?(safety?valve),?pressure?relief?valve,?sequence?valve,?pressure?switch,?etc.;?flow?control?valves?including?throttle,?adjusting?valves,?flow?diversion?valve?assembly;?Directional?control?valve?includes?a?check?valve,?check?valve,?shuttle?valve,?valve?and?so?on.?Under?the?control?of?different?ways,?hydraulic?valves?can?be?divided?into?switching?control?valves,?control?valves?and?the?fixed?value?proportional?control?valve.?? Auxiliary?components,?including?fuel?tanks,?filters,?tubing?and?pipe?joints,?seals,?quick?couplings,?high?pressure?ball?valve,?hose?assembly,?pressure?fittings,?pressure?gauge,?oil?level,?oil?temperature?meter?and?so?on.?? Hydraulic?system?of?hydraulic?oil?is?the?work?of?the?energy?transfer?medium,?a?variety?of?mineral?oil,?emulsion,?oil?hydraulic?molding?Hop?categories? The?role?of?the?hydraulic?system?is?to?help?humanity?work.?Mainly?by?the?implementation?of?components?to?rotate?or?pressure?into?a?reciprocating?motion.?? Hydraulic?principle?：It?consists?of?two?cylinders?of?different?sizes?and?composition?of?fluid?in?the?fluid?full?of?water?or?oil.?Water?is?called?"hydraulic?press";?the?said?oil?filled?"hydraulic?machine."?Each?of?the?two?liquid?a?sliding?piston,?if?the?increase?in?the?small?piston?on?the?pressure?of?a?certain?value,?according?to?Pascal's?law,?small?piston?to?the?pressure?of?the?pressure?through?the?liquid?passed?to?the?large?piston,?piston?top?will?go?a?long?way?to?go.?Based?cross-sectional?area?of?the?small?piston?is?S1,?plus?a?small?piston?in?the?downward?pressure?on?the?F1.?Thus,?a?small?piston?on?the?liquid?pressure?to?P?=?F1/SI,?Can?be?the?same?size?in?all?directions?to?the?transmission?of?liquid.?"By?the?large?piston?is?also?equivalent?to?the?inevitable?pressure?P.?If?the?large?piston?is?the?cross-sectional?area?S2,?the?pressure?P?on?the?piston?in?the?upward?pressure?generated?F2?=?PxS2?Cross-sectional?area?is?a?small?multiple?of?the?piston?cross-sectional?area.?From?the?type?known?to?add?in?a?small?piston?of?a?smaller?force, the?piston?will?be?in?great?force,?for?which?the?hydraulic?machine?used?to?suppress?plywood,?oil,?extract?heavy?objects,?such?as?forging?steel.? The?secret?of?hydraulic?systems?success?and?widespread?use?is?its?versatility?and?manageability．Fluid?power?is?not?hindered?by?the?geometry?operations?when?the?potential?difference?between?the?tool?and?the?work?piece?is?sufficiently?high,?a?transient?spark?discharges?through?the?fluid,?removing?a?very?small?amount?of?metal?from?the?work?piece?of?the?machine?as?is?the?ease?in?mechanical?systems．Alsopower?can?be?transmitted?in?almost?limitless?quantities?because?fluid?systems?are?not?so?limited?by?the?physical?1imitations?of?materials?as?are?the?electrical?systems．For?examplethe?performance?of?an?electromagnet?is?limited?by?The?saturation?limit?of?steel．On?the?otherhandthe?power?limit?of?fluid?systems?is?1imited?only?by?the?strength?capacity?of?the?material．? Industry?is?going?to?depend?more?and?more?on?automation?in?order?to?increase?productivity.Thisincludes?remote?and?direct?control?of?production?operationsmanufacturing?processes。and?materials?handling．Fluid?power?is?the?muscle?of?automation?because?of?advantages?in?the?following?four?major?categories．? 1?The?precise?convenient?control?by?operating?a?simple?joystick?and?buttons,?the?operators?of?the?hydraulic?system?and?can?immediately?start,?stop,?and?deceleration?and?can?provide?any?power,?position?precision?for?one?over?ten?thousand?inch?position?control.?A?make?the?pilot?rises?and?fall?the?landing?gear?on?the?hydraulic?system,?when?the?pilot?to?a?certain?direction?control?valves,?pressure?oil?into?hydraulic?cylinder?of?a?cavity?and?came?down?on?the?landing?gear.?The?pilot?to?move?in?the?opposite?direction?control?valves,?allow?the?oil?into?the?hydraulic?cylinder?of?another?chamber?to?take?back?on?the?landing?gear.?? 2?Multiplication?of?force．?A?fluid?power?system(without?using?cumbersome?gears，pulleys，and?levers)Can?multiply?forces?Simply?and?efficiently?from?a?fraction?of?an?ounce?to?several?hundred?tons?of?output．? 3?Constant?force?or?torque．Only?fluid?power?systems?are?capable?of?providing?constant?force?or?torque?regardless?of?speed?changes．This?is?accomplished?whether?the?work?output?moves?a?few?inches?per?hourseveral?hundred?inches?per?minutea?few?revolutions?per?hour．or?thousands?of?revolutions?per?minute．?4?Simplicity，safety，economy．general，fluid?power?systems?use?fewer?moving?parts?thant?of?high?temperature,?hydraulic?oil?expansion?will?occur,?resulting?in?increased?compression,?so?that?action?can?not?be?very?good?control?of?transmission.?Solution:?heat?is?the?inherent?characteristics?of?the?hydraulic?system,?not?only?to?minimize?eradication.?Use?good?quality?hydraulic?oil,?hydraulic?piping?arrangement?should?be?avoided?as?far?as?possible?the?emergence?of?bend,?the?use?of?high-quality?pipe?and?fittings,?hydraulic?valves,?etc.? 2?The?vibration?of?the?vibration?of?the?hydraulic?system?is?also?one?of?its?malaise.?As?a?result?of?hydraulic?oil?in?the?pipeline?flow?of?high-speed?impact?and?the?control?valve?to?open?the?closure?of?the?impact?of?the?process?are?the?reasons?for?the?vibration?system.?Strong?vibration?control?action?will?cause?the?system?to?error,?the?system?will?also?be?some?of?the?more?sophisticated?equipment?error,?resulting?in?system?failures.?Solutions:?hydraulic?pipe?should?be?fixed?to?avoid?sharp?bends.?To?avoid?frequent?changes?in?flow?direction,?can?not?avoid?damping?measures?should?be?doing?a?good?job.?The?entire?hydraulic?system?should?have?good?damping?measures,?while?avoiding?the?external?local?oscillator?on?the?system.? 3?The?leakage?of?the?hydraulic?system?leak?into?inside?and?outside?the?leakage.?Leakage?refers?to?the?process?with?the?leak?occurred?in?the?system,?such?as?hydraulic?piston-cylinder?on?both?sides?of?the?leakage,?the?control?valve?spool?and?valve?body,?such?as?between?the?leakage.?Although?no?internal?leakage?of?hydraulic?fluid?loss,?but?due?to?leakage,?the?control?of?the?established?movements?may?be?affected?until?the?cause?system?failures.?Outside?means?the?occurrence?of?leakage?in?the?system?and?the?leakage?between?the?external?environments.?Direct?leakage?of?hydraulic?oil?into?the?environment,?in?addition?to?the?system?will?affect?the?working?environment,?not?enough?pressure?will?cause?the?system?to?trigger?a?fault.?Leakage?into?the?environment?of?the?hydraulic?oil?was?also?the?danger?of?fire.?Solution:?the?use?of?better?quality?seals?to?improve?the?machining?accuracy?of?equipment.? In?the?hydraulic?system?and?its?system，the?sealing?device?to?prevent?leakage?of?the?work?of?media?within?and?outside?the?dust?and?the?intrusion?of?foreign?bodies.?Seals?played?the?role?of?components,?namely?seals.?Medium?will?result?in?leakage?of?waste,?pollution?and?environmental?machinery?and?even?give?rise?to?malfunctioning?machinery?and?equipment?for?personal?accident.?Leakage?within?the?hydraulic?system?will?cause?a?sharp?drop?in?volumetric?efficiency,?amounting?to?less?than?the?required?pressure,?can?not?even?work.?Micro-invasive?system?of?dust?particles?can?cause?or?exacerbate?friction?hydraulic?component?wear,?and?further?lead?to?leakage.? Therefore,?seals?and?sealing?device?is?an?important?hydraulic?equipment?component.?The?reliability?of?its?work?and?life?is?a?measure?of?the?hydraulic?system?an?important?indicator?of?good?or?bad.?In?addition?to?the?closed?space,?are?the?use?of?seals,?so?that?two?adjacent?coupling?surface?of?the?gap?between?the?need?to?control?the?liquid?can?be?sealed?following?the?smallest?gap.?In?the?contact?seal,?pressed?into?self-seal-style?and?self-styled?self-tight?seal?(is,?sealed?lips)?two.? 指 導 教 師 評 語 外文翻譯成績： 指導教師簽字： 年 月 日 注：1. 指導教師對譯文進行評閱時應注意以下幾個方面：①翻譯的外文文獻與畢業(yè)設(shè)計（論文）的主題是否高度相關(guān)，并作為外文參考文獻列入畢業(yè)設(shè)計（論文）的參考文獻；②翻譯的外文文獻字數(shù)是否達到規(guī)定數(shù)量（3 000字以上）；③譯文語言是否準確、通順、具有參考價值。 2. 外文原文應以附件的方式置于譯文之后。 9