液壓畢業(yè)設計外文翻譯

1、<p><b>　　什么是液壓？</b></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、無件和液壓油。動力元件的作用是將原動機的機械能轉換成液體的壓力能，指液壓系統(tǒng)中的油泵，它向整個液壓系統(tǒng)提供動力。液壓泵的結構形式一般有齒輪泵、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換為機械能，驅動負載作直線往復運動或回轉運動

2、。控制元件(即各種液壓閥)在液壓系統(tǒng)中控制和調節(jié)液體的壓力、流量和方向。根據(jù)控制功能的不同，液壓閥可分為村力控制閥、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、壓力表、油位油溫計等。 液

3、壓油是液壓系統(tǒng)中傳遞能量的工作介質，有各種礦物油、乳化液和合成型液壓油等幾大類。 </p><p><b>　　液壓的原理 </b></p><p>　　它是由兩個大小不同的液缸組成的，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，

4、將大活塞頂上去。設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在大活塞上所產生的向上的壓力F2=PxS2 </p><p>　　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

5、物、鍛壓鋼材等。 </p><p><b>　　液壓傳動的發(fā)展史 </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，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,以水壓機的形式將其應用于工業(yè)上,誕生了世界上第一臺水壓機。1905年

6、將工作介質水改為油,又進一步得到改善。 </p><p>　　第一次世界大戰(zhàn)(1914-1918)后液壓傳動廣泛應用,特別是1920年以后,發(fā)展更為迅速。液壓元件大約在 19 世紀末 20 世紀初的20年間,才開始進入正規(guī)的工業(yè)生產階段。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。20 世紀初康斯坦丁?尼斯克(G?Constantimsco)對

7、能量波動傳遞所進行的理論及實際研究;1910年對液力傳動(液力聯(lián)軸節(jié)、液力變矩器等)方面的貢獻，使這兩方面領域得到了發(fā)展。 </p><p>　　第二次世界大戰(zhàn)(1941-1945)期間,在美國機床中有30%應用了液壓傳動。應該指出,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

8、先地位。 </p><p>　　液壓傳動有許多突出的優(yōu)點，因此它的應用非常廣泛，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、橋梁操縱機構等；發(fā)電廠渦輪機調速裝置、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、船尾推進器等；特殊技術用的巨型天線控制裝置

9、、測量浮標、升降旋轉舞臺等；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。</p><p><b>　　齒輪泵</b></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相互嚙合旋轉，這個殼體的內部類似“8”字形，兩個齒輪裝在里面，齒輪的外徑及兩側與殼體緊密配合。來自于

10、擠出機的物料在吸入口進入兩個齒輪中間，并充滿這一空間，隨著齒的旋轉沿殼體運動，最后在兩齒嚙合時排出。 </p><p>　　在術語上講，齒輪泵也叫正排量裝置，即像一個缸筒內的活塞，當一個齒進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，泵每轉一轉

11、，排出的量是一樣的。隨著驅動軸的不間斷地旋轉，泵也就不間斷地排出流體。泵的流量直接與泵的轉速有關。 實際上，在泵內有很少量的流體損失，這使泵的運行效率不能達到100％，因為這些流體被用來潤滑軸承及齒輪兩側，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)擠出物料來說，仍可以達到93％～98％的效率。 </p><p>　　對于粘度或密度在

12、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，比如在排出口側放一個濾網或一個限制器，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)。 </p><p>　　對于一臺泵的轉速，實際上是有限制的，這主要取決于工藝流體，如果傳送的是油類，泵則能以很高的速度轉動，但當流

13、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。 推動高粘流體進入吸入口一側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品，即不同的規(guī)格及排量(每轉一周所排出的量)。這些泵將與具體的應用工藝相配合，以使系統(tǒng)能力及價格達到最優(yōu)。 </p><p>　　PEP－II泵

14、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”型軸承結合了強制潤滑機理，使聚合物經軸承表面，并返回到泵的進口側，以確保旋轉軸的有效潤滑。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密封結構與聚四氟唇型密封共同構成水冷密封。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卻到半熔融狀態(tài)而形成自密封。也可以采用Rheosea

15、l密封，它在軸封內表上加工有反向螺旋槽，可使聚合物被反壓回到進口。為便于安裝，制造商設計了一個環(huán)形螺栓安裝面，以使與其它設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。 </p><p>　　齒輪泵由一個獨立的電機驅動，可有效地阻斷上游的壓力脈動及流量

16、波動。在齒輪泵出口處的壓力脈動可以控制在1％以內。在擠出生產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的剪切及駐留時間，降低擠塑溫度及壓力脈動以提高生產率及產品質量。 本文摘自《《》》</p><p>　　What is Hydraulic?</p><p>　　A complete hydraulic system consist

17、s of five parts, namely, power components, the implementation of components, control components, no parts and hydraulic oil. The role of dynamic components of the original motive fluid into mechanical energy to the press

18、ure 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. Implementation of components (such as h

19、ydraulic cylinders and hy</p><p>　　Hydraulic principle </p><p>　　It consists of two cylinders of different sizes and composition of fluid in the fluid full of water or oil. Water is called "

20、;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, s

21、mall 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 </p><p>　　Can be the same size i

22、n 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 pr

23、essure generated F2 = PxS2 </p><p>　　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

24、force, for which the hydraulic machine used to suppress plywood, oil, extract heavy objects, such as forging steel. </p><p>　　History of the development of hydraulic </p><p>　　And air pressure d

25、rive hydraulic fluid as the transmission is made according to the 17th century, Pascal's principle of hydrostatic pressure to drive the development of an emerging technology, the United Kingdom in 1795 Joseph (Joseph

26、 Braman ,1749-1814), in London water as a medium to form hydraulic press used in industry, the birth of the world's first hydraulic press. Media work in 1905 will be replaced by oil-water and further improved. </p

27、><p>　　World War I (1914-1918) after the extensive application of hydraulic transmission, especially after 1920, more rapid development. Hydraulic components in the late 19th century about the early 20th centur

28、y, 20 years, only started to enter the formal phase of industrial production. 1925 Vickers (F. Vikers) the invention of the pressure balanced vane pump, hydraulic components for the modern industrial or hydraulic transmi

29、ssion of the gradual establishment of the foundation. The early 20th century </p><p>　　The Second World War (1941-1945) period, in the United States 30% of machine tool applications in the hydraulic transmis

30、sion. It should be noted that the development of hydraulic transmission in Japan than Europe and the United States and other countries for nearly 20 years later. Before and after in 1955, the rapid development of Japan&#

31、39;s hydraulic drive, set up in 1956, "Hydraulic Industry." Nearly 20 to 30 years, the development of Japan's fast hydraulic transmission, a world leader. </p><p>　　Hydraulic transmission There

32、 are many outstanding advantages, it is widely used, such as general workers. Plastic processing industry, machinery, pressure machinery, machine tools, etc.; operating machinery engineering machinery, construction machi

33、nery, agricultural machinery, automobiles, etc.; iron and steel industry metallurgical machinery, lifting equipment, such as roller adjustment device; civil water projects with flood control the dam gates and devices, be

34、d lifts installations, bridges a</p><p>　　The concept of gear pump is very simple, that it is two of the most basic form of the same size gear in a close co-operation of mutual engagement with the rotating s

35、hell, the shell's internal similar "8" shape, the two gears mounted inside , the diameter of gear and work closely with both sides and shell. From the extruder the material inhaled into the mouth of two int

36、ermediate gears, and full of the space, with the teeth along the shell of the rotary movement, the final two hours from the meshi</p><p>　　Speaking in terms of gear, also known as positive displacement pump

37、device, that is, inside the cylinder like a piston, when a tooth to another tooth space of the fluid, the liquid was squeezed mechanically to row out. Because the liquid is incompressible, so the liquid and the tooth at

38、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 phenomenon occurs on a row and, therefore, the pump provides a continuous ex</p&g

39、t;<p>　　In fact, there is little pump of the fluid loss, which makes the operation of pumps can not achieve 100% efficiency, as these fluids are used to on both sides of bearing and gear lubrication, and the pump

40、body is also not possible with no gap, it can not be so that 100% of fluid discharged from the export, so a small amount of fluid loss is inevitable. However, a good pump can be run out of material for the majority, will

41、 still be able to achieve 93% ~ 98% efficiency. </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 example, in the export si

42、de, 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, the pump will maintain

43、a constant flow, until the device in the weakest parts of the mechanical limit (usually equipped with a torque limiter). </p><p>　　For a pump speed, in fact, there are restrictions, which mainly depends on t

44、he process fluid, if the transmission is oil, pump can rotate at high speed, but when the fluid is a high viscosity of the polymer melt, such restrictions will be significantly reduced. </p><p>　　Promote blo

45、od flow into the intake side of the two tooth space is very important, if not fill in this space is full, the pump will not be able to discharge the flow of accurate, so the value of PV (pressure × velocity) is also

46、 a limiting factor, and is a process variable. As a result of these restrictions, gear pump manufacturers will provide a range of products, that is, different specifications and emission (per week to the emission of volu

47、me). These pumps will fit the specific application of </p><p>　　PEP-II pump shaft gear and a total of one species hardened using technology, will be a longer working life. "D"-type bearing a combin

48、ation of forced lubrication mechanism, so that the polymer surface by the bearing, and return to the import side of pump to ensure effective lubrication of the rotation axis. This feature reduces the degradation of polym

49、ers and the possibility of being stranded. Precision machining of the pump body can "D"-type gear shaft with precision bearings to ensure non-eccen</p><p>　　PEP-II with a gear pump with the pump to

50、 match the specifications of the heating elements for the user matching, which ensures rapid heating and heat control. Heating the body and pump in different ways, the damage to these components is limited to a board, th

51、e pump has nothing to do with the whole. </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 out

52、let 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 red