液壓系統(tǒng)外文翻譯

1、<p><b>　　液壓系統(tǒng)</b></p><p>　　液壓傳動和氣壓傳動稱為流體傳動，是根據(jù)17世紀(jì)帕斯卡提出的液體靜壓力傳動原理而發(fā)展起來的一門新興技術(shù)，1795年英國約瑟夫?布拉曼(Joseph Braman,1749-1814)，在倫敦用水作為工作介質(zhì)，以水壓機的形式將其應(yīng)用于工業(yè)上，誕生了世界上第一臺水壓機。1905年將工作介質(zhì)水改為油，又進(jìn)一步得到改善。</p&

2、gt;<p>　　第一次世界大戰(zhàn)(1914-1918)后液壓傳動廣泛應(yīng)用，特別是1920年以后，發(fā)展更為迅速。液壓元件大約在 19 世紀(jì)末 20 世紀(jì)初的20年間，才開始進(jìn)入正規(guī)的工業(yè)生產(chǎn)階段。1925 年維克斯(F.Vikers)發(fā)明了壓力平衡式葉片泵,為近代液壓元件工業(yè)或液壓傳動的逐步建立奠定了基礎(chǔ)。20 世紀(jì)初康斯坦丁?尼斯克(G?Constantimsco)對能量波動傳遞所進(jìn)行的理論及實際研究;1910年對液力傳動

3、(液力聯(lián)軸節(jié)、液力變矩器等)方面的貢獻(xiàn)，使這兩方面領(lǐng)域得到了發(fā)展。</p><p>　　第二次世界大戰(zhàn)(1941-1945)期間,在美國機床中有30%應(yīng)用了液壓傳動。應(yīng)該指出,日本液壓傳動的發(fā)展較歐美等國家晚了近 20 多年。在 1955 年前后 , 日本迅速發(fā)展液壓傳動,1956 年成立了“液壓工業(yè)會”。近20～30 年間，日本液壓傳動發(fā)展之快，居世界領(lǐng)先地位。</p><p>　　液壓

4、傳動有許多突出的優(yōu)點，因此它的應(yīng)用非常廣泛，如一般工業(yè)用的塑料加工機械、壓力機械、機床等；行走機械中的工程機械、建筑機械、農(nóng)業(yè)機械、汽車等；鋼鐵工業(yè)用的冶金機械、提升裝置、軋輥調(diào)整裝置等；土木水利工程用的防洪閘門及堤壩裝置、河床升降裝置、橋梁操縱機構(gòu)等；發(fā)電廠渦輪機調(diào)速裝置、核發(fā)電廠等等；船舶用的甲板起重機械（絞車）、船頭門、艙壁閥、船尾推進(jìn)器等；特殊技術(shù)用的巨型天線控制裝置、測量浮標(biāo)、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

5、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。</p><p>　　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、輔助元件和液壓油。 </p><p>　　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。 </p><p>　　執(zhí)行元件(

6、如液壓缸和液壓馬達(dá))的作用是將液體的壓力能轉(zhuǎn)換為機械能，驅(qū)動負(fù)載作直線往復(fù)運動或回轉(zhuǎn)運動。 </p><p>　　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

7、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。 </p><p>　　輔助元件包括油箱、濾油器、油管及管接頭、密封圈、壓力表、油位油溫計等。 </p><p>　　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。</p><p>　　齒輪泵的概念是很簡單的，即它的最基本形式就是兩個尺寸相同的齒輪在一個緊密配合的殼體內(nèi)

8、相互嚙合旋轉(zhuǎn)，這個殼體的內(nèi)部類似“8”字形，兩個齒輪裝在里面，齒輪的外徑及兩側(cè)與殼體緊密配合。來自于擠出機的物料在吸入口進(jìn)入兩個齒輪中間，并充滿這一空間，隨著齒的旋轉(zhuǎn)沿殼體運動，最后在兩齒嚙合時排出。 </p><p>　　在術(shù)語上講，齒輪泵也叫正排量裝置，即像一個缸筒內(nèi)的活塞，當(dāng)一個齒進(jìn)入另一個齒的流體空間時，液體就被機械性地擠排出來。因為液體是不可壓縮的，所以液體和齒就不能在同一時間占據(jù)同一空間，這樣，液體就

9、被排除了。由于齒的不斷嚙合，這一現(xiàn)象就連續(xù)在發(fā)生，因而也就在泵的出口提供了一個連續(xù)排除量，泵每轉(zhuǎn)一轉(zhuǎn)，排出的量是一樣的。隨著驅(qū)動軸的不間斷地旋轉(zhuǎn)，泵也就不間斷地排出流體。泵的流量直接與泵的轉(zhuǎn)速有關(guān)。 實際上，在泵內(nèi)有很少量的流體損失，這使泵的運行效率不能達(dá)到100％，因為這些流體被用來潤滑軸承及齒輪兩側(cè)，而泵體也絕不可能無間隙配合，故不能使流體100％地從出口排出，所以少量的流體損失是必然的。然而泵還是可以良好地運行，對大多數(shù)擠出物料來

10、說，仍可以達(dá)到93％～98％的效率。 </p><p>　　對于粘度或密度在工藝中有變化的流體，這種泵不會受到太多影響。如果有一個阻尼器，比如在排出口側(cè)放一個濾網(wǎng)或一個限制器，泵則會推動流體通過它們。如果這個阻尼器在工作中變化，亦即如果濾網(wǎng)變臟、堵塞了，或限制器的背壓升高了，則泵仍將保持恒定的流量，直至達(dá)到裝置中最弱的部件的機械極限(通常裝有一個扭矩限制器)。對于一臺泵的轉(zhuǎn)速，實際上是有限制的，這主要取決于工藝流

11、體，如果傳送的是油類，泵則能以很高的速度轉(zhuǎn)動，但當(dāng)流體是一種高粘度的聚合物熔體時，這種限制就會大幅度降低。 推動高粘流體進(jìn)入吸入口一側(cè)的兩齒空間是非常重要的，如果這一空間沒有填充滿，則泵就不能排出準(zhǔn)確的流量，所以PV值(壓力×流速)也是另外一個限制因素，而且是一個工藝變量。由于這些限制，齒輪泵制造商將提供一系列產(chǎn)品，即不同的規(guī)格及排量(每轉(zhuǎn)一周所排出的量)。這些泵將與具體的應(yīng)用工藝相配合，以使系統(tǒng)能力及價格達(dá)到最優(yōu)。 <

12、/p><p>　　PEP－II泵的齒輪與軸共為一體，采用通體淬硬工藝，可獲得更長的工作壽命?！癉”型軸承結(jié)合了強制潤滑機理，使聚合物經(jīng)軸承表面，并返回到泵的進(jìn)口側(cè)，以確保旋轉(zhuǎn)軸的有效潤滑。這一特性減少了聚合物滯留并降解的可能性。精密加工的泵體可使“D”型軸承與齒輪軸精確配合，確保齒輪軸不偏心，以防齒輪磨損。Parkool密封結(jié)構(gòu)與聚四氟唇型密封共同構(gòu)成水冷密封。這種密封實際上并不接觸軸的表面，它的密封原理是將聚合物冷

13、卻到半熔融狀態(tài)而形成自密封。也可以采用Rheoseal密封，它在軸封內(nèi)表上加工有反向螺旋槽，可使聚合物被反壓回到進(jìn)口。為便于安裝，制造商設(shè)計了一個環(huán)形螺栓安裝面，以使與其它設(shè)備的法蘭安裝相配合，這使得筒形法蘭的制造更容易。 PEP－II齒輪泵帶有與泵的規(guī)格相匹配的加熱元件，可供用戶選配，這可保證快速加溫和熱量控制。與泵體內(nèi)加熱方式不同，這些元件的損壞只限于一個板子上，與整個泵無關(guān)。 </p><p>　　齒輪泵由

14、一個獨立的電機驅(qū)動，可有效地阻斷上游的壓力脈動及流量波動。在齒輪泵出口處的壓力脈動可以控制在1％以內(nèi)。在擠出生產(chǎn)線上采用一臺齒輪泵，可以提高流量輸出速度，減少物料在擠出機內(nèi)的剪切及駐留時間，降低擠塑溫度及壓力脈動以提高生產(chǎn)率及產(chǎn)品質(zhì)量。 </p><p>　　液壓系統(tǒng)的作用就是幫助人類做工。主要是由執(zhí)行元件把壓力變成轉(zhuǎn)動或往復(fù)運動。</p><p>　　液壓的原理：它是由兩個大小不同的液缸

15、組成的，在液缸里充滿水或油。充水的叫“水壓機”；充油的稱“油壓機”。兩個液缸里各有一個可以滑動的活塞，如果在小活塞上加一定值的壓力，根據(jù)帕斯卡定律，小活塞將這一壓力通過液體的壓強傳遞給大活塞，將大活塞頂上去。設(shè)小活塞的橫截面積是S1，加在小活塞上的向下的壓力是F1。于是，小活塞對液體的壓強為P=F1/SI, 能夠大小不變地被液體向各個方向傳遞”。大活塞所受到的壓強必然也等于P。若大活塞的橫截面積是S2，壓強P在大活塞上所產(chǎn)生的向上的壓力

16、F2=PxS2截面積是小活塞橫截面積的倍數(shù)。從上式知，在小活塞上加一較小的力，則在大活塞上會得到很大的力，為此用液壓機來壓制膠合板、榨油、提取重物、鍛壓鋼材等。 </p><p>　　液壓系統(tǒng)由信號控制和液壓動力兩部分組成，信號控制部分用于驅(qū)動液壓動力部分中的控制閥動作。</p><p>　　液壓動力部分采用回路圖方式表示，以表明不同功能元件之間的相互關(guān)系。液壓源含有液壓泵、電動機和液壓輔

17、助元件；液壓控制部分含有各種控制閥，其用于控制工作油液的流量、壓力和方向；執(zhí)行部分含有液壓缸或液壓馬達(dá)，其可按實際要求來選擇。</p><p>　　在分析和設(shè)計實際任務(wù)時，一般采用方框圖顯示設(shè)備中實際運行狀況。 空心箭頭表示信號流，而實心箭頭則表示能量流。</p><p>　　基本液壓回路中的動作順序—控制元件（二位四通換向閥）的換向和彈簧復(fù)位、執(zhí)行元件（雙作用液壓缸）的伸出和回縮以及溢流

18、閥的開啟和關(guān)閉。 對于執(zhí)行元件和控制元件，演示文稿都是基于相應(yīng)回路圖符號，這也為介紹回路圖符號作了準(zhǔn)備。</p><p>　　根據(jù)系統(tǒng)工作原理，您可對所有回路依次進(jìn)行編號。如果第一個執(zhí)行元件編號為0，則與其相關(guān)的控制元件標(biāo)識符則為1。如果與執(zhí)行元件伸出相對應(yīng)的元件標(biāo)識符為偶數(shù)，則與執(zhí)行元件回縮相對應(yīng)的元件標(biāo)識符則為奇數(shù)。 不僅應(yīng)對液壓回路進(jìn)行編號，也應(yīng)對實際設(shè)備進(jìn)行編號，以便發(fā)現(xiàn)系統(tǒng)故障。</p>

19、<p>　　DIN ISO1219-2標(biāo)準(zhǔn)定義了元件的編號組成，其包括下面四個部分：設(shè)備編號、回路編號、元件標(biāo)識符和元件編號。如果整個系統(tǒng)僅有一種設(shè)備，則可省略設(shè)備編號。</p><p>　　實際中，另一種編號方式就是對液壓系統(tǒng)中所有元件進(jìn)行連續(xù)編號，此時，元件編號應(yīng)該與元件列表中編號相一致。 這種方法特別適用于復(fù)雜液壓控制系統(tǒng)，每個控制回路都與其系統(tǒng)編號相對應(yīng)</p><p>

20、　　與機械傳動、電氣傳動相比，液壓傳動具有以下優(yōu)點：</p><p>　　1、液壓傳動的各種元件，可以根據(jù)需要方便、靈活地來布置。</p><p>　　2、重量輕、體積小、運動慣性小、反應(yīng)速度快。</p><p>　　3、操縱控制方便，可實現(xiàn)大范圍的無級調(diào)速（調(diào)速范圍達(dá)2000：1）。</p><p>　　4、可自動實現(xiàn)過載保護(hù)。</p

21、><p>　　5、一般采用礦物油作為工作介質(zhì)，相對運動面可自行潤滑，使用壽命長。</p><p>　　6、很容易實現(xiàn)直線運動。</p><p>　　7、很容易實現(xiàn)機器的自動化，當(dāng)采用電液聯(lián)合控制后，不僅可實現(xiàn)更高程度的自動控制過程，而且可以實現(xiàn)遙控。</p><p><b>　　液壓系統(tǒng)的缺點：</b></p>

22、<p>　　1、由于流體流動的阻力和泄露較大，所以效率較低。如果處理不當(dāng)，泄露不僅污染場地，而且還可能引起火災(zāi)和爆炸事故。</p><p>　　2、由于工作性能易受到溫度變化的影響，因此不宜在很高或很低的溫度條件下工作。</p><p>　　3、液壓元件的制造精度要求較高，因而價格較貴。</p><p>　　4、由于液體介質(zhì)的泄露及可壓縮性影響，不能得到

23、嚴(yán)格的傳動比。</p><p>　　5、液壓傳動出故障時不易找出原因；使用和維修要求有較高的技術(shù)水平。</p><p>　　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(dá)不到所需要的工作壓力，甚至不能進(jìn)行工作。侵入

24、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(jìn)一步導(dǎo)致泄漏。</p><p>　　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(biāo)。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。</p><p&

25、gt;<b>　　液壓系統(tǒng)的三大頑疾</b></p><p>　　1、發(fā)熱 由于傳力介質(zhì)（液壓油）在流動過程中存在各部位流速的不同，導(dǎo)致液體內(nèi)部存在一定的內(nèi)摩擦，同時液體和管路內(nèi)壁之間也存在摩擦，這些都是導(dǎo)致液壓油溫度升高的原因。溫度升高將導(dǎo)致內(nèi)外泄漏增大，降低其機械效率。同時由于較高的溫度，液壓油會發(fā)生膨脹，導(dǎo)致壓縮性增大，使控制動作無法很好的傳遞。解決辦法：發(fā)熱是液壓系統(tǒng)的固有特征，無法

26、根除只能盡量減輕。使用質(zhì)量好的液壓油、液壓管路的布置中應(yīng)盡量避免彎頭的出現(xiàn)、使用高質(zhì)量的管路以及管接頭、液壓閥等。</p><p>　　2、振動 液壓系統(tǒng)的振動也是其痼疾之一。由于液壓油在管路中的高速流動而產(chǎn)生的沖擊以及控制閥打開關(guān)閉過程中產(chǎn)生的沖擊都是系統(tǒng)發(fā)生振動的原因。強的振動會導(dǎo)致系統(tǒng)控制動作發(fā)生錯誤，也會使系統(tǒng)中一些較為精密的儀器發(fā)生錯誤，導(dǎo)致系統(tǒng)故障。解決辦法：液壓管路應(yīng)盡量固定，避免出現(xiàn)急彎。避免頻繁

27、改變液流方向，無法避免時應(yīng)做好減振措施。整個液壓系統(tǒng)應(yīng)有良好的減振措施，同時還要避免外來振源對系統(tǒng)的影響。</p><p>　　3、泄漏 液壓系統(tǒng)的泄漏分為內(nèi)泄漏和外泄漏。內(nèi)泄漏指泄漏過程發(fā)生在系統(tǒng)內(nèi)部，例如液壓缸活塞兩邊的泄漏、控制閥閥芯與閥體之間的泄漏等。內(nèi)泄漏雖然不會產(chǎn)生液壓油的損失，但是由于發(fā)生泄漏，既定的控制動作可能會受到影響，直至引起系統(tǒng)故障。外泄漏是指發(fā)生在系統(tǒng)和外部環(huán)境之間的泄漏。液壓油直接泄漏到

28、環(huán)境中，除了會影響系統(tǒng)的工作環(huán)境外，還會導(dǎo)致系統(tǒng)壓力不夠引發(fā)故障。泄漏到環(huán)境中的液壓油還有發(fā)生火災(zāi)的危險。解決辦法：采用質(zhì)量較好的密封件，提高設(shè)備的加工精度。</p><p>　　液壓元件將向高性能、高質(zhì)量、高可靠性、系統(tǒng)成套方向發(fā)展；向低能耗、低噪聲、振動、無泄漏以及污染控制、應(yīng)用水基介質(zhì)等適應(yīng)環(huán)保要求方向發(fā)展；開發(fā)高集成化高功率密度、智能化、機電一體化以及輕小型微型液壓元件；積極采用新工藝、新材料和電子、傳感

29、等高新技術(shù)。</p><p>　　液力偶合器向高速大功率和集成化的液力傳動裝置發(fā)展，開發(fā)水介質(zhì)調(diào)速型液力偶合器和向汽車應(yīng)用領(lǐng)域發(fā)展，開發(fā)液力減速器，提高產(chǎn)品可靠性和平均無故障工作時間；液力變矩器要開發(fā)大功率的產(chǎn)品，提高零部件的制造工藝技術(shù)，提高可靠性，推廣計算機輔助技術(shù)，開發(fā)液力變矩器與動力換檔變速箱配套使用技術(shù)；液粘調(diào)速離合器應(yīng)提高產(chǎn)品質(zhì)量，形成批量，向大功率和高轉(zhuǎn)速方向發(fā)展。</p><p

30、>　　氣動行業(yè)：產(chǎn)品向體積小、重量輕、功耗低、組合集成化方向發(fā)展，執(zhí)行元件向種類多、結(jié)構(gòu)緊湊、定位精度高方向發(fā)展；氣動元件與電子技術(shù)相結(jié)合，向智能化方向發(fā)展；元件性能向高速、高頻、高響應(yīng)、高壽命、耐高溫、耐高壓方向發(fā)展，普遍采用無油潤滑，應(yīng)用新工藝、新技術(shù)、新材料。</p><p>　?。?）采用的液壓元件高壓化，連續(xù)工作壓力達(dá)到40Mpa，瞬間最高壓力達(dá)到48Mpa；</p><p&g

31、t;　?。?）調(diào)節(jié)和控制方式多樣化；</p><p>　　（3）進(jìn)一步改善調(diào)節(jié)性能，提高動力傳動系統(tǒng)的效率；</p><p>　　（4）發(fā)展與機械、液力、電力傳動組合的復(fù)合式調(diào)節(jié)傳動裝置；</p><p>　?。?）發(fā)展具有節(jié)能、儲能功能的高效系統(tǒng)；</p><p>　?。?）進(jìn)一步降低噪聲；</p><p>　?。?

32、）應(yīng)用液壓螺紋插裝閥技術(shù)，緊湊結(jié)構(gòu)、減少漏油。</p><p>　　Hydraulic System</p><p>　　Hydraulic presser drive and air pressure drive hydraulic fluid as the transmission is made according to the 17th century, Pascal's

33、principle of hydrostatic pressure to drive the development of an emerging technology, the United Kingdom in 1795 ? Braman Joseph (Joseph Braman ,1749-1814), in London water as a medium to form hydraulic press used in ind

34、ustry, the birth of the world's first hydraulic press. Media work in 1905 will be replaced by oil-water and further improved.</p><p>　　After the World War I (1914-1918) ,because of the extensive applicat

35、ion of hydraulic transmission, especially after 1920, more rapid development. Hydraulic components in the late 19th century about the early 20th century, 20 years, only started to enter the formal phase of industrial pro

36、duction. 1925 Vickers (F. Vikers) the invention of the pressure balanced vane pump, hydraulic components for the modern industrial or hydraulic transmission of the gradual establishment of the foundation. The ear</p&g

37、t;<p>　　The Second World War (1941-1945) period, in the United States 30% of machine tool applications in the hydraulic transmission. It should be noted that the development of hydraulic transmission in Japan than

38、 Europe and the United States and other countries for nearly 20 years later. Before and after in 1955, the rapid development of Japan's hydraulic drive, set up in 1956, "Hydraulic Industry." Nearly 20 to 30

39、 years, the development of Japan's fast hydraulic transmission, a world leader.</p><p>　　Hydraulic transmission There are many outstanding advantages, it is widely used, such as general industrial use of

40、 plastics processing machinery, the pressure of machinery, machine tools, etc.; operating machinery engineering machinery, construction machinery, agricultural machinery, automobiles, etc.; iron and steel indu-stry metal

41、lurgical machinery, lifting equipment, such as roller adjustment device; civil water projects with flood control and dam gate devices, bed lifts installations, bridge</p><p>　　A complete hydraulic system con

42、sists of five parts, namely, power components, the implementation of components, control components, auxiliary components and hydraulic oil. The role of dynamic components of the original motive fluid into mechanica

43、l energy to the pressure that the hydraulic system of pumps, it is to power the entire hydraulic system. The structure of the form of hydraulic pump gears are generally pump, vane pump and piston pump. Implementatio

44、n of components (such as hydr</p><p>　　Control components (that is, the various hydraulic valves) in the hydraulic system to control and regulate the pressure of liquid, flow rate and direction. According to

45、 the different control functions, hydraulic pressure control valve can be divided into valves, flow control valves and directional control valve. Pressure control valves are divided into benefits flow valve (safety valve

46、), pressure relief valve, sequence valve, pressure relays, etc.; flow control valves including throttle, adjusti</p><p>　　The concept of gear pump is very simple, that it is two of the most basic form of the

47、 same size gear in a close cooperation of mutual engagement with the rotating shell, the shell's internal similar "8" shape, the two gears mounted inside , the diameter of gear and work closely with both si

48、des and shell. From the extruder the material inhaled into the mouth of two intermediate gears, and full of the space, with the teeth along the shell of the rotary movement, the final two hours from the meshin</p>

49、<p>　　Speaking in terms of gear, also known as positive displacement pump device, that is, inside the cylinder like a piston, when a tooth to another tooth space of the fluid, the liquid was squeezed mechanically t

50、o row out. Because the liquid is incompressible, so the liquid and the tooth at the same time will not be able to occupy the same space, so that the liquid has been ruled out. Because of the constant mesh gear, this phen

51、omenon occurs on a row and, therefore, the pump provides a continuous ex</p><p>　　For the viscosity or density change in the process fluid, the pump will not be affected too much. If there is a damper, for e

52、xample, in the export side, one row or a limiter filter, pumps will push fluid through them. If the damper changes in their work, that is, if the filters become dirty, blocked, or limiter on the back of the hypertension,

53、 the pump will maintain a constant flow, until the device in the weakest parts of the mechanical limit (usually equipped with a torque limiter). For a pump</p><p>　　PEP-II pump shaft gear and a total of one

54、species hardened using technology, will be a longer working life. "D"-type bearing a combination of forced lubrication mechanism, so that the polymer surface by the bearing, and return to the import side of pum

55、p to ensure effective lubrication of the rotation axis. This feature reduces the degradation of polymers and the possibility of being stranded. Precision machining of the pump body can "D"-type gear shaft with

56、precision bearings to ensure noneccent</p><p>　　Gear pump by an independent motor drive, to be effective in blocking the upper reaches of the pressure pulsation and flow fluctuations. Gear pump in the outlet

57、 of the pressure fluctuation can be controlled within 1%. In the extrusion production line using a gear pump, can increase the output flow rate of material in the extruder to reduce the shear and residence time to reduce

58、 the extrusion temperature and pressure fluctuation in order to enhance productivity and product quality.</p><p>　　The role of the hydraulic system is to help humanity work. Mainly by the implementation of c

59、omponents to rotate or pressure into a reciprocating motion. </p><p>　　Hydraulic principle ：it consists of two cylinders of different sizes and composition of fluid in the fluid full of water or oil. Water i

60、s called "hydraulic press"; the said oilfilled "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

61、'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 </p><p>　　In the analysis and design of

62、 the actual task, the general block diagram shows the actual operation of equipment. Hollow arrow indicates the signal flow, while the solid arrows that energy flow. Basic hydraulic circuit of the action sequence Co

63、ntrol components (two four-way valve) and the spring to reset for the implementation of components (double-acting hydraulic cylinder), as well as the extending and retracting the relief valve opened and closed. For the i

64、mplementation of components and</p><p>　　Working principle of the system, you can turn on all circuits to code. If the first implementation of components numbered 0, the control components associated with th

65、e identifier is 1. Out with the implementation of components corresponding to the identifier for the even components, then retracting and implementation of components corresponding to the identifier for the odd component

66、s. Hydraulic circuit carried out not only to deal with numbers, but also to deal with the actual device ID, in ord</p><p>　　DIN ISO1219-2 standard definition of the number of component composition, which inc

67、ludes the following four parts: device ID, circuit ID, component ID and component ID. The entire system if only one device, device number may be omitted. Practice, another way is to code all of the hydraulic system

68、components for numbers at this time, components and component code should be consistent with the list of numbers. This method is particularly applicable to complex hydraulic control system, each co</p><p>　　

69、With mechanical transmission, electrical transmission compared to the hydraulic drive has the following advantages: 1, a variety of hydraulic components, can easily and flexibly to layout. </p><p>　　2,

70、light weight, small size, small inertia, fast response. </p><p>　　3, to facilitate manipulation of control, enabling a wide range of stepless speed regulation (speed range of 2000:1). 4, to achieve over

71、load protection automatically. 5, the general use of mineral oil as a working medium, the relative motion can be self-lubricating surface, long service life. 6, it is easy to achieve linear motion. 7, it is

72、 easy to achieve the automation of machines, when the joint control of the use of electro-hydraulic, not only can achieve a higher degree o</p><p>　　The shortcomings of the hydraulic system: 1, as a result

73、of the resistance to fluid flow and leakage of the larger, so less efficient. If not handled properly, leakage is not only contaminated sites, but also may cause fire and explosion. 2, vulnerable performance as a result

74、 of the impact of temperature change, it would be inappropriate in the high or low temperature conditions. 3, the manufacture of precision hydraulic components require a higher, more expensive and hence the price. 4, d

75、ue</p><p>　　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 compon

76、ents, 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 wi

77、ll cause a sharp drop in volumetric efficiency, amounting to less than the required p</p><p>　　Therefore, seals and sealing device is an important hydraulic equipment components. The reliability of its work

78、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 th

79、e liquid can be sealed following the smallest gap. In the contact seal, pressed into self-seal-style and self-styled self-tight seal (ie, sealed lips) two.</p><p>　　The three hydraulic system diseases </p

80、><p>　　1, as a result of heat transmission medium (hydraulic oil) in the flow velocity in various parts of the existence of different, resulting in the existence of a liquid within the internal friction of liqu

81、ids and pipelines at the same time there is friction between the inner wall, which are a result of hydraulic the reasons for the oil temperature. Temperature will lead to increased internal and external leakage, reducing

82、 its mechanical efficiency. At the same time as a result of high temperature,</p><p>　　2, the vibration of the vibration of the hydraulic system is also one of its malaise. As a result of hydraulic oil in th

83、e 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 sy

84、stem will also be some of the more sophisticated equipment error, resulting in system failures. Solutions: hydraulic pipe should be fixed to avoid sharp bends. </p><p>　　3, the leakage of the hydraulic syste

85、m leak into inside and outside the leakage 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 bo

86、dy, 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 occur

87、rence of leakage in the</p><p>　　Hydraulic coupling to high-speed high-power and integrated development of hydraulic transmission equipment, development of water hydraulic coupling medium speed and the field

88、 of automotive applications to develop hydraulic reducer, improve product reliability and working hours MTBF; hydraulic torque converter to the development of high-power products, parts and components to improve the manu

89、facturing process technology to improve reliability, promote computeraided technology, the development of </p><p>　　Pneumatic Industry:Products to small size, light weight, low power consumption, integrated

90、portfolio of development, the implementation of the various types of components, compact structure, high positioning accuracy of the direction of development; pneumatic components and electronic technology, to the intell

91、igent direction of development; component performance to high-speed, high-frequency, high-response, high-life, high temperature, high voltage direction, commonly used oil-free lubrication, </p><p>　　(1) used

92、 high-pressure hydraulic components and the pressure of continuous work to reach 40Mpa, the maximum pressure to achieve instant 48Mpa; (2) diversification of regulation and control; (3) to further improve the r

93、egulation performance, increase the efficiency of the powertrain; (4) development and mechanical, hydraulic, power transmission of the composite portfolio adjustment gear; (5) development of energy saving, ener