車輛工程專業(yè)畢業(yè)論文外文翻譯---履帶車輛轉(zhuǎn)向機構(gòu)的研究現(xiàn)狀及發(fā)展趨勢

1、<p>　　The Track Vehicle Changes Direction Research Present Condition and DevelopmentTrends of The Organization</p><p>　　1 change direction the research present condition of the organization</p>

2、<p>　　Different classification in basis method, the track vehicle changes direction organization can according to vehicle is in change direction process the power flows of deliver the way is divided into the single

3、 power flows to change direction the organization to flow to change direction the organization with a power, and also can according to in change direction process two the sport of side trackses have no the contact but is

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5、n organization flow to change direction the general structure in organization method is at became soon the organization, is the most simple method to constitute track vehicle change direction to spread to move.The single

6、 power flows to change direction the organization to change direction the organization most in brief, among them most in common usely change direction the </p><p>　　Bad soon the machine changes direction the

7、 organization[2,3] can make vehicle several why the speed of the center position still keeps in change direction process the original driving the car straightly is soon, being a When the complete system in side move, cha

8、nge direction the radius over small, but another side track speed over high, change direction the Cape speed over big, for this reason a power for needing changing direction power very bigly, would outrunning generally l

9、aunching machine r</p><p>　　1.2 pairs of powerses flow to change direction the organization after launching machine, will launch the machine power be divided in to become soon with change direction two roa

10、ds be juxtaposed to deliver, ising a double of powers to flow to change direction the organization.A power flows to change direction the organization will used for keeping the pushes forward of become soon the organizat

11、ion is different from result in leftly, the right side track speed differs of change direction the or</p><p>　　(1)the machine type a power flow to change direction the organization to flow the foundation top

12、 that change direction the organization to appear at the earliest stage in the single power of was a machine to kept the with changed direction two powers flowed all from machinery to realized type a power to flowed to

13、change direction the organization[3].It is this kind to change direction the organization main from two become soon box( a lord become soon the box, a cent moves a box of), the planet </p><p>　　(2)the machin

14、e liquid press type a power flows to change direction the organization machine</p><p>　　The type of changes direction the organization changes direction the function easily under the influence of the pilot&

15、#39;s driver's technique, physical strength term moving the machine to wear away with the clutch, system, and bring the pilot the fatigue easily.Give or get an electric shock along with the machine the liquid press a

16、nd technical development in engineering in machine in person, the machine type change direction the organization to will be eliminated on the big power tractor, bulldoze</p><p>　　An a lot of weakness for two

17、th lateral speeds differing realizing having no class controling, again overcoming machine type changing direction organization.If the liquid presses the motor do not work, only coming from central spread the dynamic pow

18、er flow, the vehicle makes the straight line drives; if only have the liquid that come from the power press the motor flows, the vehicle can realize to change direction radius as the zero changing direction originally; i

19、f input at the same time two roa</p><p>　　2 change direction the pure liquid in trend </p><p>　　(1)in development in organization press to have no the class changes direction the organiz

20、ation wants to realize the track vehicle changes direction the radius can control and continue to have no the class changes of change direction the function, the adoption capacity type liquid presses to pump to press wit

21、h the liquid motor etc. has no the class become soon a piece is a more realistic viable method.The pure liquid presses to change direction the organization[7 9] of ～ss pass to pump of positi</p><p>　　(2)the

22、compound changes direction organization as to overcome the pure liquid presses the above blemish that change direction the organization, appearing now the small liquid in power in various adoptions press the liquid of a

23、dollar piece presses the compound changes direction the project[7].A pump a motor project: this project is to solves the liquid press the direct and the most simple project in shortage in a power in a dollar, its functio

24、n press with pure liquid to change direction same, bu</p><p>　　(3)the machine liquid presses the consecution has no the class changes direction the organization machine liquid presses the consecution has no

25、the class changes direction the organization[10 21] of ～ss are in simple liquid pressing cent in machine spreading the foundation that move the principle, adopting the different machine organization parameter combine, an

26、d press with liquid a dollar the piece matches with of a kind of latest model changes direction the organization.It can guarantee at con</p><p>　　履帶車輛轉(zhuǎn)向機構(gòu)的研究現(xiàn)狀及發(fā)展趨勢</p><p>　　1、轉(zhuǎn)向機構(gòu)的研究現(xiàn)狀</p>

27、;<p>　　依據(jù)不同的分類方法,履帶車輛轉(zhuǎn)向機構(gòu)可根據(jù)車輛在轉(zhuǎn)向過程中功率流的傳遞方式分為單功率流轉(zhuǎn)向機構(gòu)和雙功率流轉(zhuǎn)向機構(gòu),也可根據(jù)在轉(zhuǎn)向過程中兩側(cè)履帶的運動有無聯(lián)系而分為獨立式轉(zhuǎn)向機構(gòu)和差速式轉(zhuǎn)向機構(gòu)。</p><p>　　1.1　單功率流轉(zhuǎn)向機構(gòu)單功率流轉(zhuǎn)向機構(gòu)一般構(gòu)造方法是在變速機構(gòu)后串聯(lián)某種轉(zhuǎn)向機構(gòu),是構(gòu)成履帶車輛轉(zhuǎn)向傳動的最為簡單的方法。單功率流轉(zhuǎn)向機構(gòu)是最簡單的轉(zhuǎn)向機構(gòu),其中最常用的

28、有轉(zhuǎn)向離合器、單差速器、雙差速器、行星轉(zhuǎn)向機構(gòu)等。轉(zhuǎn)向離合器都是多片式摩擦離合器,靠摩擦表面的摩擦力傳遞轉(zhuǎn)矩,當分離某一側(cè)的轉(zhuǎn)向離合器時,就可以減少或切斷該側(cè)驅(qū)動輪所傳遞的轉(zhuǎn)矩使車輛轉(zhuǎn)向。轉(zhuǎn)向半徑的大小由驅(qū)動輪所傳轉(zhuǎn)矩的減少量即離合器分離的程度所決定。轉(zhuǎn)向離合器由于結(jié)構(gòu)簡單、制造方便,在早期的中小型履帶式拖拉機、推土機上得到了廣泛運用。但由于其操縱性差、生產(chǎn)效率低、能耗較大,隨著履帶車輛功率的不斷增大,轉(zhuǎn)向離合器的應用將會受到一定的限制

29、。單差速器轉(zhuǎn)向機構(gòu)可使車輛幾何中心位置的速度在轉(zhuǎn)向過程中仍保持原直線行駛車速,當一側(cè)完全制動時,轉(zhuǎn)向半徑過小,而另一側(cè)履帶速度過高、轉(zhuǎn)向角速度過大,因此所需轉(zhuǎn)向功率很大,會超出一般發(fā)動機的功率限制,駕駛員若持續(xù)轉(zhuǎn)向,稍有不慎就會使發(fā)動機熄火,因而只能靠滑磨,用較大半徑轉(zhuǎn)向,或極不平穩(wěn)地以小半徑斷續(xù)轉(zhuǎn)向。因此這種單差速器轉(zhuǎn)向機構(gòu)現(xiàn)在幾乎不再采用。雙差速器轉(zhuǎn)向機構(gòu)可使履帶車輛在轉(zhuǎn)向時慢速側(cè)</p><p>　　1.2

30、　雙功率流轉(zhuǎn)向機構(gòu)在發(fā)動機后,將發(fā)動機功率分成變速和轉(zhuǎn)向兩路并列傳遞,就是雙功率流轉(zhuǎn)向機構(gòu)。雙功率流轉(zhuǎn)向機構(gòu)將用于直駛推進的變速機構(gòu)與造成左、右側(cè)履帶速度差的轉(zhuǎn)向機構(gòu)在傳動系中并列,轉(zhuǎn)向機構(gòu)在車輛直駛時不造成兩側(cè)履帶的速度差,在轉(zhuǎn)向時,變速流提供各檔不同的直線行駛速度與轉(zhuǎn)向機構(gòu)造成的兩側(cè)履帶的速度差匯流,實現(xiàn)車輛的轉(zhuǎn)向。</p><p>　　(1)機械式雙功率流轉(zhuǎn)向機構(gòu)在單功率流轉(zhuǎn)向機構(gòu)的基礎上最早出現(xiàn)的是直駛和

31、轉(zhuǎn)向兩功率流均由機械裝置來實現(xiàn)的機械式雙功率流轉(zhuǎn)向機構(gòu)。此種轉(zhuǎn)向機構(gòu)主要由兩個變速箱(一個主變速箱、一個分動箱)、行星齒輪機構(gòu)、離合器和行星機構(gòu)制動器組成,在轉(zhuǎn)向性能上較單功率流轉(zhuǎn)向機構(gòu)有很大提高,但是它的轉(zhuǎn)向半徑仍然是有級的。檔位越低,得到的轉(zhuǎn)向半徑越小;檔位越高,得到的轉(zhuǎn)向半徑越大。仍然不能適應車輛在所有不同曲率的道路上用圓滑軌跡轉(zhuǎn)向行駛的需要,也不能排除部分接合摩擦元件進行滑磨轉(zhuǎn)向及由滑磨所帶來的一系列問題。</p>

32、<p>　　(2)機械液壓式雙功率流轉(zhuǎn)向機構(gòu)機械式轉(zhuǎn)向機構(gòu)的轉(zhuǎn)向性能容易受到駕駛員的駕駛技術(shù)、體力條件和離合器、制動器磨損的影響,并且容易給駕駛員帶來疲勞。隨著機電液壓及人機工程技術(shù)的發(fā)展,機械式轉(zhuǎn)向機構(gòu)必將會在大功率拖拉機、推土機等工程車輛上遭到淘汰。在機械系統(tǒng)上附加液壓泵—液壓馬達驅(qū)動的機械—液壓轉(zhuǎn)向系統(tǒng)將逐漸得到應用。機械液壓式雙功率流轉(zhuǎn)向機構(gòu)由發(fā)動機、變量泵、控制閥、定量馬達、多檔變速箱以及后橋轉(zhuǎn)向差動機構(gòu)組成。它將

33、由發(fā)動機傳來的機械功率流在多檔變速箱的輸入軸上分流,一路流經(jīng)由液壓泵-液壓馬達組成的轉(zhuǎn)向調(diào)速系統(tǒng);另一路流經(jīng)多檔變速箱,最后在行星排上合流,然后經(jīng)行星排中的某一部件(如行星架)傳到車輛的終傳動軸上。由于液壓泵和液壓馬達可以無級控制,因此使用這類轉(zhuǎn)向機構(gòu)既可獲得車輛兩側(cè)的速度差實現(xiàn)無級控制,又克服了機械式轉(zhuǎn)向機構(gòu)的許多缺點。若液壓馬達不工作,只有來自中央傳動的功率流,車輛作直線行駛;若只有來自液壓馬達的功率流,車輛可實現(xiàn)轉(zhuǎn)向半徑為零的原地

34、轉(zhuǎn)向;若同時輸入兩路功率流,由于液壓馬達可實現(xiàn)無級控制,因此車輛兩側(cè)履帶驅(qū)動輪轉(zhuǎn)速差可以有無窮多個,可得到無窮多個轉(zhuǎn)向半徑,即可實現(xiàn)無級轉(zhuǎn)向,駕</p><p>　　2、轉(zhuǎn)向機構(gòu)發(fā)展趨勢</p><p>　　(1)純液壓無級轉(zhuǎn)向機構(gòu)要實現(xiàn)履帶車輛轉(zhuǎn)向半徑可控且連續(xù)無級變化的轉(zhuǎn)向性能,采用容積式液壓泵和液壓馬達等無級變速元件是較現(xiàn)實可行的方法。純液壓轉(zhuǎn)向機構(gòu)通過泵的正反兩向無級變量調(diào)節(jié),實現(xiàn)

35、發(fā)動機動力經(jīng)雙流傳動轉(zhuǎn)向路到匯流行星排間的無級變化的傳動比,最終實現(xiàn)車輛向左右兩側(cè)的轉(zhuǎn)向半徑可連續(xù)無級變化直駛時,通過液壓泵和液壓馬達的閉鎖(變量泵的排量為零)來實現(xiàn)轉(zhuǎn)向零軸的閉鎖,從而保持穩(wěn)定的直駛。在變速機構(gòu)掛空檔轉(zhuǎn)向的情況下,發(fā)動機所發(fā)出的功率全部由轉(zhuǎn)向路的液壓元件傳遞,可實現(xiàn)車輛原地轉(zhuǎn)向。目前的液壓工業(yè)水平還難以得到功率足夠大且性能優(yōu)良的液壓元件,并且液壓系統(tǒng)的效率低,這是純液壓無級轉(zhuǎn)向技術(shù)發(fā)展的最大障礙。</p>

36、<p>　　(2)復合轉(zhuǎn)向機構(gòu)為克服純液壓轉(zhuǎn)向機構(gòu)的上述缺陷,目前出現(xiàn)了多種采用功率較小的液壓元件的液壓復合轉(zhuǎn)向方案。雙泵雙馬達方案:此方案是解決液壓元件功率不足最直接、最簡單的方案,其性能與純液壓轉(zhuǎn)向相同,但兩套液壓元件并聯(lián)使該機構(gòu)體積重量較大,效率仍較低。機械液壓復合方案:該方案在采用雙流液壓轉(zhuǎn)向的同時,保留一套機械轉(zhuǎn)向機構(gòu)。利用功率不大的液壓元件實現(xiàn)大半徑轉(zhuǎn)向的連續(xù)無級變化;利用機械轉(zhuǎn)向機構(gòu)實現(xiàn)有級的小半徑轉(zhuǎn)向。這種轉(zhuǎn)

37、向機構(gòu)不能實現(xiàn)整個半徑范圍的無級變化。雙半徑液壓轉(zhuǎn)向方案:該方案采用有兩種輸出速比的液壓馬達,在較好路面上轉(zhuǎn)向時采用較高的輸出轉(zhuǎn)速,當?shù)孛媲闆r不好時則換用低速輸出以克服較大的轉(zhuǎn)向阻力。液壓液力復合轉(zhuǎn)向方案:該方案是以有限功率的液壓元件進行無級轉(zhuǎn)向,助力偶合器在轉(zhuǎn)向液壓馬達力矩不足時及時提供助力矩。該方案雖減少了液壓元件但效率會更低?？傊?采用液壓元件的無級變速特性來實現(xiàn)履帶車輛的無級轉(zhuǎn)向是較佳的選擇,解決液壓元件功率不足和效率低則是該方

38、向研究的重點。</p><p>　　(3)機械液壓連續(xù)無級轉(zhuǎn)向機構(gòu)機械液壓連續(xù)無級轉(zhuǎn)向機構(gòu)是在簡單液壓機械分流傳動原理的基礎上,采用不同的機械機構(gòu)參數(shù)組合,并與液壓元件配合的一種最新型的轉(zhuǎn)向機構(gòu)。它能保證在連續(xù)無級輸出轉(zhuǎn)速的前提下應用較小的液壓元件大幅度提高車輛的輸出總功率,并且其傳動效率遠遠超過純液壓轉(zhuǎn)向機構(gòu)的傳動效率。它代表著履帶車輛轉(zhuǎn)向機構(gòu)的發(fā)展方向。研究開發(fā)性能優(yōu)良的機械液壓連續(xù)無級轉(zhuǎn)向機構(gòu)、優(yōu)化匹配該類