The Track Vehicle Changes Direction Research Present Condition and DevelopmentTrends of The Organization1 change direction the research present condition of the organizationDifferent 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 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 divided into the independent type change direction the organization with bad soon the type changes direction the organization.1.1 single powers establish a certain changing direction the organization after flowing change direction the single power in 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 power flows to change direction the organization to change direction the organization most in brief, among them most in common usely change direction the clutch, single bad soon the machine, double is bad soon the machine, planet changes direction organization etc.Change direction the clutch1,2 is all a friction that several types rub the clutch, depending the friction surface to deliver to turn the , being the separation some on changing direction the clutch laterally, can reduce or cut off that side drive a round delivers of turn the make vehicle changed direction.Change direction the size of the radius from drive a decrease for spreads to turn the measures namely the degree that clutch separate decides.Change direction the clutch is simple because of the construction, manufacturing convenience, got the extensive application on the small scaled track in inside in earlier period type tractor, bulldozer.But because its manipulate the sex bad, produce the efficiency low, can consume bigger, enlarge continuously along with the track vehicle power, change direction the application of the clutch will suffer certainly of restrict.SingleBad soon the machine changes direction the organization2,3 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, change 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 launching machine restrict, if the pilot keep on changing direction, have a little bit the immodesty and then will make launch the machine fire, as a result can depend to slip to whet, using than the greater half path changes direction, or pole is not fair and softly break to change direction continuously with the lesser half path.Therefore this kind of is single bad soon the machine change direction the organization to no longer adopt almost now.The speed that a speed for differing soon machine changing direction organization3,4 can making track vehicle at changing direction slowly soon side track lowering is equal to the fast side track the increment, the for this reason vehicle changes direction of average speed and straightly the speed that drive same alike.But because a variety for badly soon machine cant completely system moving first side track, vehicle cant originally changing direction, and changing direction radius scope has no usage to change direction the clutch big, changing direction the going smoothly worse.While changing direction, the fast side track accelerates, therefore launching the affixture of the machine carry the ratio adoption change direction the clutch big.The double is bad soon the machine be constituted by wheel gear of change direction the organization, with change direction the clutch compare the spare parts number little, bear to whet the sex good, the life span is longer.The planet changes direction the organization4,5 moves with the system from a planet a department the machine constitutes.The operation planet the system on the organization moves the machine can change two sides drives the round drives the dint size make vehicle changed direction.It is that type of to change direction the organization opposite in change direction the clutch change direction the organization can deliver the bigger changing direction the dint , can realize an athletic and fixed stalk wheel gear organization fall through of two free a planet for of flat-out decomposition with synthesizing, planet organization a three dollar as have the bad relating to soon; change direction the organization to much order to deliver the motive, and the internal path in organization faces the dint mutually equilibrium.But is complicated because of its construction, only industry in big power tractor, bulldozer and other heavy type vehicle last application.Single weakness that power change direction is obvious, vehicle only contain several fix of change direction the radius, press to rule not of change direction When the radius change direction, want to is slipped by friction a piece to whet to realize, and is hard to get the stability change direction the radius accurately; the next in order in change direction process rub a dollar piece of violent slip to whet to will bring to have fever with wear away, make spread to move the efficiency lower, especially in the big power change direction work appearance next, would exsit the bigger power lose, with the result that often need to be declined to change direction soon; moreover, the violent friction also make easy damage in organization, cause the work dependable bad, the life span lower.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 roads 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 organization is different from result in leftly, the right side track speed differs of change direction the organization to be juxtaposed in spread move department, change direction the organization when the vehicle keeps the did not result in twoth the speed of side trackses are bad, while changing direction, became to flow each file of offering soon to drive the speed straightly with change direction the organization results in of two the speed of side trackses differ to remit to flow, realizing the vehicle change direction.(1)the machine type a power flow to change direction the organization to flow the foundation top 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 change direction the organization3.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 wheel gear organization, clutch moves with the planet organization system the machine constitutes, the single power flows to change direction in changing direction function the organization has the very big increasing, but it still change direction the radius is to have the class.The file is more low, getting of change direction the radius more small; the file is more high, getting of change direction the radius more big.Cant still adapt to the vehicle road in all different curvatures on the tactful track that change direction to drive with the demand, also cant expel parts of coalescences rub a piece proceeds to slip to whet to change direction and from slip to whet an a series of problem for bringing.(2)the machine liquid press type a power flows to change direction the organization machineThe type of changes direction the organization changes direction the function easily under the influence of the pilots drivers 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 and technical development in engineering in machine in person, the machine type change direction the organization to will be eliminated on the big power tractor, bulldozer.etc. engineering vehicle necessarily.Press in the last additional liquid in system in machine the liquid of that pump the motor presses the machine liquid drives to press to change direction the system will get the application gradually.The machine liquid press type a power flows to change direction the organization5,6 from launch the machine and change the deal pump, control valve, fixed amount motor, many files become soon box and empress bridges change direction to differ to move the organization constitutes.It will spread to flow from the machine that launch the machine power in many files became soon the importation stalk of the box last cent flow, all the way flow through was pressed by liquid pump- liquid press motor constitute of change direction adjust soon system; another all the way flow through many files became soon box, finally experienced star row top confluence, then was lined up by planet of some a the parts( such as planet) spread to the vehicle to spread to move the stalk top eventually.Because the liquid presses to pump to press with the liquid the motor can have no the class controls, therefore using the this type of changing direction the organization since can acquire the carAn a lot of weakness for twoth 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 power 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; if input at the same time two road powers flow, because the liquid presses the motor can realize to have no the class controls, for this reason vehicle two side tracks drive the rotation to have soon and will barely do much more endless, can get the much more endless changes direction the radius, can immediately realize to have no the class changes direction, pilot as long as manipulate to change direction the dish turns to move the liquid presses the device, can make vehicle driven along the certain arc stablely.This kind of changes direction the organization not only have the construction good, have no the friction a piece, life span is long, the efficiency is high and work dependable, arrange simple, maintain the adjustment little and lower to can consume to wait the characteristics the outside, but also it is not a motive to pass the part or cut off all a side track in working function to the system move a the side drives a the round realizes to change direction of, but two side tracks deliver the motive always, can realizes nicely like this the motive change direction, basic ascend a safety for slippery phenomenon, being applicable to proceeding being partial to carrying pushing soil with cutting off root homework; at sloping fields changing direction cant appearing conversing direction phenomenon, increases vehicle that dissolves the track; because of changing direction do not cut off the motive, the average car of the for this reason vehicle does not lower soon; the track do not stop driving, breaking to the soil little, in loosenning soft soil of pass the sex good; change direction the size of the radius can control arbitrarily, increasing the flexibility of the track vehicle, change direction steady; change direction vehicle can develop with drive the high work in same function straightly; realizes easily a the root manipulates the pole to control in to back with change direction.2 change direction the pure liquid in trend (1)in development in organization press to have no the class changes direction the organization 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 with 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 organization7 9 of ss pass to pump of positive and negative two directions have no the class changes the deal regulates, realizing to launch the mobile dint was spread by double to move to change direction the road arrives to remit the popular star row has no the class changes of spreading and moving ratio, end realize the vehicle face or so two change direction laterally radius can continue to have no the class the variety keeps the , pass the liquid press to pump with the liquid press the motor shuts the lock( change the row that deal pump measureses for zero) to realize to change direction the zero to shut the lock axially, from but keeps to keep the stablely.Under the situation of becoming soon the organization hangs the blank on schedule to change direction, launch machine a power for sending out all to press from the liquid that change direction the road a piece deliver, can realize the vehicle change direction originally.The current liquid presses the industry level returns the hard getting the power enough and big and the good liquid in function presses a dollar an efficiency for, and the liquid presses the system low, this is the biggest obstacle that pure liquid press to have no the class change direction the technique develops.(2)the 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 dollar piece presses the compound changes direction the project7.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 function press with pure liquid to change direction same, but two sets of liquids press a piece merge to make the organizations physical volume weight bigger, the efficiency is still lower.The machine liquid presses to reunite the project: that project is adopting a double of flowing the liquid press to change direction of at the same time, reserve a set of machines change direction the organization.Make use of the power not very of the liquid presses a dollar the piece realizes the greater half path changes direction of have no the class variety continuously; make use of the organization that machine change direction lesser half path realizes the class changes direction.This kind of change direction the organization falls through whole radius scope has no the class variety.A radius liquid presses to change direction the project: that project adoption contain two kinds of exportations soon the liquid that compare presses the motor, when the good road ascends to change direction adoption the higher exportation turns soon, native out of fix the hour then change to output with the low speed to overcome bigger changing direction the resistance.The liquid presses the liquid dint compound changes direction the project: that project presses with the liquid of the limited power a piece proceeds to have no the class changes direction, the help matches the machine accidentally at change direction the liquid press the motor dint not enough hour on time provide the help .That project although reduce the liquid press a piece efficiencies would be much lower.In fine, adopt the liquid press a dollar a point for having no class becoming soon characteristic to realizing track vehicle having no class changing direction is good choice, solving liquid pressing a dollar a power shortage then is low with the efficiency that direction is investigative.(3)the machine liquid presses the consecution has no the class changes direction the organization machine liquid presses the consecution has no the class changes direction the organization10 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, and press with liquid a dollar the piece matches with of a kind of latest model changes direction the organization.It can guarantee at continue to have no the class output the next applied small liquid in premise that turn to press the total power in an exportation for significantly increasing vehicle in a dollar soon, and its spread to move the efficiency far far ahead pure the liquid presses to change direction the organization spreads to move the efficiency.It represents the development direction that track vehicle change direction organization.The research develops the good machine in function liquid presses the consecution has no the class changes direction the organization, excellent turn to match the that type of turning. Construction parameter that face organization is the point lesson of the current vehicle engineering realm. 履帶車輛轉(zhuǎn)向機(jī)構(gòu)的研究現(xiàn)狀及發(fā)展趨勢1、轉(zhuǎn)向機(jī)構(gòu)的研究現(xiàn)狀依據(jù)不同的分類方法,履帶車輛轉(zhuǎn)向機(jī)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(jī)構(gòu)和雙功率流轉(zhuǎn)向機(jī)構(gòu),也可根據(jù)在轉(zhuǎn)向過程中兩側(cè)履帶的運(yùn)動有無聯(lián)系而分為獨(dú)立式轉(zhuǎn)向機(jī)構(gòu)和差速式轉(zhuǎn)向機(jī)構(gòu)。1.1單功率流轉(zhuǎn)向機(jī)構(gòu)單功率流轉(zhuǎn)向機(jī)構(gòu)一般構(gòu)造方法是在變速機(jī)構(gòu)后串聯(lián)某種轉(zhuǎn)向機(jī)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(jī)構(gòu)是最簡單的轉(zhuǎn)向機(jī)構(gòu),其中最常用的有轉(zhuǎn)向離合器、單差速器、雙差速器、行星轉(zhuǎn)向機(jī)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(dāng)分離某一側(cè)的轉(zhuǎn)向離合器時(shí),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(jī)、推土機(jī)上得到了廣泛運(yùn)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(yīng)用將會受到一定的限制。單差速器轉(zhuǎn)向機(jī)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(dāng)一側(cè)完全制動時(shí),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(jī)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(jī)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(jī)構(gòu)現(xiàn)在幾乎不再采用。雙差速器轉(zhuǎn)向機(jī)構(gòu)可使履帶車輛在轉(zhuǎn)向時(shí)慢速側(cè)履帶降低的速度等于快速側(cè)履帶增加的速度,因此車輛轉(zhuǎn)向時(shí)的平均速度與直線行駛的速度相同。但由于雙差速器不能完全制動一側(cè)履帶,車輛不能原地轉(zhuǎn)向,且轉(zhuǎn)向半徑的變化范圍沒有使用轉(zhuǎn)向離合器的大,轉(zhuǎn)向平順性較差。轉(zhuǎn)向時(shí)快速側(cè)履帶加速,因此發(fā)動機(jī)的附加載荷比采用轉(zhuǎn)向離合器的大。雙差速器是由齒輪組成的轉(zhuǎn)向機(jī)構(gòu),與轉(zhuǎn)向離合器相比零件數(shù)目少、耐磨性好、壽命較長。行星轉(zhuǎn)向機(jī)構(gòu)由一組行星輪系和制動器組成。操作行星機(jī)構(gòu)上的制動器可以改變兩側(cè)驅(qū)動輪驅(qū)動力矩大小使車輛轉(zhuǎn)向。該類轉(zhuǎn)向機(jī)構(gòu)相對于轉(zhuǎn)向離合器轉(zhuǎn)向機(jī)構(gòu)能傳遞較大的轉(zhuǎn)向力矩,能夠?qū)崿F(xiàn)單自由度運(yùn)動的固定軸齒輪機(jī)構(gòu)所不能實(shí)現(xiàn)的二自由度的速度分解與合成,行星機(jī)構(gòu)的行星架、太陽輪、齒圈三元件之間具有差速關(guān)系;轉(zhuǎn)向機(jī)構(gòu)多點(diǎn)傳遞動力,并且機(jī)構(gòu)內(nèi)部徑向力相互平衡。但由于其結(jié)構(gòu)復(fù)雜,僅在大功率的工業(yè)拖拉機(jī)、推土機(jī)及其它重型車輛上應(yīng)用。單功率轉(zhuǎn)向的缺點(diǎn)是明顯的,車輛僅有幾個(gè)固定的轉(zhuǎn)向半徑,按非規(guī)定的轉(zhuǎn)向半徑轉(zhuǎn)向時(shí),要靠摩擦元件的滑磨來實(shí)現(xiàn),難以得到穩(wěn)定準(zhǔn)確的轉(zhuǎn)向半徑;其次是在轉(zhuǎn)向過程中摩擦元件的劇烈滑磨會帶來發(fā)熱和磨損,使傳動效率降低,特別是在較大功率的轉(zhuǎn)向工作狀態(tài)下,會存在較大的功率損失,以致常需降速轉(zhuǎn)向;另外,劇烈的摩擦也使機(jī)構(gòu)容易損壞,導(dǎo)致工作可靠性差,壽命降低。1.2雙功率流轉(zhuǎn)向機(jī)構(gòu)在發(fā)動機(jī)后,將發(fā)動機(jī)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(jī)構(gòu)。雙功率流轉(zhuǎn)向機(jī)構(gòu)將用于直駛推進(jìn)的變速機(jī)構(gòu)與造成左、右側(cè)履帶速度差的轉(zhuǎn)向機(jī)構(gòu)在傳動系中并列,轉(zhuǎn)向機(jī)構(gòu)在車輛直駛時(shí)不造成兩側(cè)履帶的速度差,在轉(zhuǎn)向時(shí),變速流提供各檔不同的直線行駛速度與轉(zhuǎn)向機(jī)構(gòu)造成的兩側(cè)履帶的速度差匯流,實(shí)現(xiàn)車輛的轉(zhuǎn)向。(1)機(jī)械式雙功率流轉(zhuǎn)向機(jī)構(gòu)在單功率流轉(zhuǎn)向機(jī)構(gòu)的基礎(chǔ)上最早出現(xiàn)的是直駛和轉(zhuǎn)向兩功率流均由機(jī)械裝置來實(shí)現(xiàn)的機(jī)械式雙功率流轉(zhuǎn)向機(jī)構(gòu)。此種轉(zhuǎn)向機(jī)構(gòu)主要由兩個(gè)變速箱(一個(gè)主變速箱、一個(gè)分動箱)、行星齒輪機(jī)構(gòu)、離合器和行星機(jī)構(gòu)制動器組成,在轉(zhuǎn)向性能上較單功率流轉(zhuǎn)向機(jī)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(yīng)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(jìn)行滑磨轉(zhuǎn)向及由滑磨所帶來的一系列問題。(2)機(jī)械液壓式雙功率流轉(zhuǎn)向機(jī)構(gòu)機(jī)械式轉(zhuǎn)向機(jī)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(jī)電液壓及人機(jī)工程技術(shù)的發(fā)展,機(jī)械式轉(zhuǎn)向機(jī)構(gòu)必將會在大功率拖拉機(jī)、推土機(jī)等工程車輛上遭到淘汰。在機(jī)械系統(tǒng)上附加液壓泵液壓馬達(dá)驅(qū)動的機(jī)械液壓轉(zhuǎn)向系統(tǒng)將逐漸得到應(yīng)用。機(jī)械液壓式雙功率流轉(zhuǎn)向機(jī)構(gòu)由發(fā)動機(jī)、變量泵、控制閥、定量馬達(dá)、多檔變速箱以及后橋轉(zhuǎn)向差動機(jī)構(gòu)組成。它將由發(fā)動機(jī)傳來的機(jī)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(dá)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(dá)可以無級控制,因此使用這類轉(zhuǎn)向機(jī)構(gòu)既可獲得車輛兩側(cè)的速度差實(shí)現(xiàn)無級控制,又克服了機(jī)械式轉(zhuǎn)向機(jī)構(gòu)的許多缺點(diǎn)。若液壓馬達(dá)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(dá)的功率流,車輛可實(shí)現(xiàn)轉(zhuǎn)向半徑為零的原地轉(zhuǎn)向;若同時(shí)輸入兩路功率流,由于液壓馬達(dá)可實(shí)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(gè),可得到無窮多個(gè)轉(zhuǎn)向半徑,即可實(shí)現(xiàn)無級轉(zhuǎn)向,駕駛員只要操縱轉(zhuǎn)向盤轉(zhuǎn)動液壓裝置,就可使車輛穩(wěn)定地沿一定的圓弧行駛。這種轉(zhuǎn)向機(jī)構(gòu)不但具有結(jié)構(gòu)性好、沒有摩擦元件、壽命長、效率高、工作可靠、布置簡便、維修調(diào)整少及降低能耗等特點(diǎn)外,而且在工作性能上它不是通過部分或全部切斷一側(cè)履帶的動力來制動一側(cè)驅(qū)動輪實(shí)現(xiàn)轉(zhuǎn)向的,而是兩側(cè)履帶始終傳遞動力,這樣可很好地實(shí)現(xiàn)動力轉(zhuǎn)向,基本上消除了履帶的打滑現(xiàn)象,適用于進(jìn)行偏載推土和切除樹根作業(yè);在坡地轉(zhuǎn)向時(shí)不會出現(xiàn)“逆轉(zhuǎn)向”現(xiàn)象,提高了車輛的安全性;由于轉(zhuǎn)向時(shí)不切斷動力,因此車輛的平均車速不降低;履帶不停駛,對土壤破壞少,在松軟土壤上的通過性好;轉(zhuǎn)向半徑的大小可任意控制,提高了履帶車輛的機(jī)動性,轉(zhuǎn)向平穩(wěn);轉(zhuǎn)向時(shí)車輛能發(fā)揮