汽車維修雙柱式液壓舉升機(jī)設(shè)計(jì)-液壓系統(tǒng)9張CAD圖
汽車維修雙柱式液壓舉升機(jī)設(shè)計(jì)-液壓系統(tǒng)9張CAD圖,汽車,維修,雙柱式,液壓,舉升機(jī),設(shè)計(jì),系統(tǒng),CAD
附錄一：
液壓系統(tǒng)
液壓傳動(dòng)和氣壓傳動(dòng)稱為流體傳動(dòng)，是根據(jù) 17 世紀(jì)帕斯卡提出的液體靜壓力傳動(dòng)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(jī)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(jī)。1905 年將工作介質(zhì)水改為油，又進(jìn)一步得到改善。
第一次世界大戰(zhàn)(1914-1918)后液壓傳動(dòng)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(dòng)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(dòng)傳遞所進(jìn)行的理論及實(shí)際研究;1910 年對液力傳動(dòng)(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。
第二次世界大戰(zhàn)(1941-1945)期間,在美國機(jī)床中有 30%應(yīng)用了液壓傳動(dòng)。應(yīng)該指出,日本液壓傳動(dòng)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(dòng),1956 年成立了“液壓工業(yè)會”。近 20～30 年間，日本液壓傳動(dòng)發(fā)展之快，居世界領(lǐng)先地位。
液壓傳動(dòng)有許多突出的優(yōu)點(diǎn)，因此它的應(yīng)用非常廣泛，如一般工業(yè)用的塑料加工機(jī)械、壓力機(jī)械、機(jī)床等；行走機(jī)械中的工程機(jī)械、建筑機(jī)械、農(nóng)業(yè)機(jī)械、汽車等；鋼鐵工業(yè)用的冶金機(jī)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(jī)構(gòu)等；發(fā)電廠渦輪機(jī)調(diào)速裝置、核發(fā)電廠等等；船舶用的甲板起重機(jī)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、船舶減搖裝置、飛行器仿真、飛機(jī)起落架的收放裝置和方向舵控制裝置等。
一個(gè)完整的液壓系統(tǒng)由五個(gè)部分組成，即動(dòng)力元件、執(zhí)行元件、控制元件、輔助元件和液壓油。
動(dòng)力元件的作用是將原動(dòng)機(jī)的機(jī)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(gè)液壓系統(tǒng)提供動(dòng)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(dá))的作用是將液體的壓力能轉(zhuǎn)換為機(jī)械能，驅(qū)動(dòng)負(fù)載作直線往復(fù)運(yùn)動(dòng)或回轉(zhuǎn)運(yùn)動(dòng)。
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、壓力表、油位油溫計(jì)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。
齒輪泵的概念是很簡單的，即它的最基本形式就是兩個(gè)尺寸相同的齒輪在一個(gè)緊密配合的殼體內(nèi)相互嚙合旋轉(zhuǎn)，這個(gè)殼體的內(nèi)部類似“8”字形，兩個(gè)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(jī)的物料在吸入口進(jìn)入兩個(gè)齒輪中間，并充滿這一空間，隨著齒的旋轉(zhuǎn)沿殼體運(yùn)動(dòng)，最后在兩齒嚙合時(shí)排出。
在術(shù)語上講，齒輪泵也叫正排量裝置，即像一個(gè)缸筒內(nèi)的活塞，當(dāng)一個(gè)齒進(jìn)入另一個(gè)齒的流體空間時(shí)，液體就被機(jī)械性地?cái)D排出來。因?yàn)橐后w是不可壓縮的， 所以液體和齒就不能在同一時(shí)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(gè)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(dòng)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(shí)際上，在泵內(nèi)有很少量的流體損失，這使泵的運(yùn)行效率不能達(dá)到 100％，因?yàn)檫@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(yùn)行，對大多數(shù)擠出物料來說，仍可以達(dá)到 93％～98％的效率。
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(gè)阻尼器，比如在排出口側(cè)放一個(gè)濾網(wǎng)或一個(gè)限制器，泵則會推動(dòng)流體通過它們。
如果這個(gè)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(jī)械極限(通常裝有一個(gè)扭矩限制器)。對于一臺泵的轉(zhuǎn)速，實(shí)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(zhuǎn)動(dòng)，但當(dāng)流體是一種高粘度的聚合物熔體時(shí)，這種限制就會大幅度降低。 推動(dòng)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(gè)限制因素，而且是一個(gè)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(jià)格達(dá)到最優(yōu)。
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(qiáng)制潤滑機(jī)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(shí)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 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(jì)了一個(gè)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(gè)板子上，與整個(gè)泵無關(guān)。
齒輪泵由一個(gè)獨(dú)立的電機(jī)驅(qū)動(dòng)，可有效地阻斷上游的壓力脈動(dòng)及流量波動(dòng)。在齒輪泵出口處的壓力脈動(dòng)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(jī)內(nèi)的剪切及駐留時(shí)間，降低擠塑溫度及壓力脈動(dòng)以提高生產(chǎn)率及產(chǎn)品質(zhì)量。
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(dòng)或往復(fù)運(yùn)動(dòng)。
液壓的原理：它是由兩個(gè)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(jī)”；充油的稱“油壓機(jī)”。兩個(gè)液缸里各有一個(gè)可以滑動(dòng)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(qiáng)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(qiáng)為 P=F1/SI, 能夠大小不變地被液體向各個(gè)方向傳遞”。大活塞所受到的壓強(qiáng)必然也等于 P。若大活塞的橫截面積是 S2，壓強(qiáng) P 在大活塞上所產(chǎn)生的向上的壓力 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(jī)來壓制膠合板、榨油、提取重物、鍛壓鋼材等。
液壓系統(tǒng)由信號控制和液壓動(dòng)力兩部分組成，信號控制部分用于驅(qū)動(dòng)液壓動(dòng)力部分中的控制閥動(dòng)作。
液壓動(dòng)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(dòng)機(jī)和液壓輔助元件；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(shí)際要求來選擇。
在分析和設(shè)計(jì)實(shí)際任務(wù)時(shí)，一般采用方框圖顯示設(shè)備中實(shí)際運(yùn)行狀況。 空心箭頭表示信號流，而實(shí)心箭頭則表示能量流。
基本液壓回路中的動(dòng)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。
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(gè)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(shí)際設(shè)備進(jìn)行編號，以便發(fā)現(xiàn)系統(tǒng)故障。
DIN ISO1219-2 標(biāo)準(zhǔn)定義了元件的編號組成，其包括下面四個(gè)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(gè)系統(tǒng)僅有一種設(shè)備，則可省略設(shè)備編號。
附錄二：
Hydraulic System
Hydraulic presser drive and air pressure drive 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 ? Braman Joseph (Joseph 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.
After the World War I (1914-1918) ,because of the extensive application 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 production. 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 early 20th century G ? Constantimscofluct- uations of the energy carried out by passing theoretical and practical research; in 1910 on the hydraulic trans- mission (hydraulic coupling, hydraulic torque converter, etc.) contributions, so that these two areas of development.
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 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 years, the development of Japan's fast hydraulic transmission, a world leader.
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 indu-stry 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 antirolling devices, aircraft simulation, aircraft retractable landing gear and rudder control devices and other devices.
A complete hydraulic system consists 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 mechanical 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.
Implementation of components (such as hydraulic cylinders and hydraulic motors) which is the pressure of the liquid can be converted to mechanical energy to drive the load for a straight line reciprocating movement or rotational movement.
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 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), pressure relief valve, sequence valve, pressure relays, etc.; flow control valves including throttle, adjusting the valves, flow diversion valve sets, etc.; directional control valve includes a one-way valve , one-way fluid control valve, shuttle valve, valve and so on. Under the control of different ways, can be divided into the hydraulic valve control switch valve, control valve and set the value of the ratio control valve.
Auxiliary components, including fuel tanks, oil filters, tubing and pipe joints, seals, pressure gauge, oil level, such as oil dollars.
Hydraulic oil in the hydraulic system is the work of the energy transfer medium, there are a variety of mineral oil, emulsion oil hydraulic molding Hop categories.
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 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 sides 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 meshing teeth.
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 to 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 phenomenon occurs on a row and, therefore, the pump provides a continuous export to exclude the amount of a turn each pump, the volume of discharge is the same. With the continuous rotation of the driveshaft, pump fluid is continuously discharged. Pump flow directly to the speed of the pump. 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 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 still be able to achieve 93% ~ 98% efficiency.
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 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, 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 speed, in fact, there are restrictions, which mainly depends on the 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. Promote blood 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 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 (perweek to the emission of volume). These pumps will fit the specific application of technology to enable the system to achieve optimal capacity and price.
PEP-II pump shaft gear and a total of one 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 pump 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 precision bearings to ensure noneccentric gear shaft to prevent gear wear. Structure and Parkool PTFE sealing lip sealed water
cooled sealed together. This shaft seal does not actually contact the surface, it is the principle of the sealing polymer to a semimolten state cooling and the formation of self sealing. Can also be used Rheoseal sealing, seal it inside the table are reverse spiral groove processing, the polymer can be imported back to the antipressure. In order to facilitate the installation, the manufacturer has designed the installation of a ring bolt, so that the flange and install other equipment line, which makes the manufacture of tube flange easier. PEP-II with a gear pump with the pump to 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, the pump has nothing to do with the whole.
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 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 the extrusion temperature and pressure fluctuation in order to enhance productivity and product quality.
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 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'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.
Hydraulic system and hydraulic power control signal is composed of two parts, the signal control of some parts of the hydraulic power used to drive the control valve movement.
Part of the hydraulic power means that the circuit diagram used to show the different functions of the interrelationship between components. Containing the source of hydraulic pump, hydraulic motor and auxiliary components; hydraulic control part contains a variety of control valves, used to control the flow of oil, pressure and direction; operative or hydraulic cylinder with hydraulic motors, according to the actual requirements of their choice.
In the analysis and design of 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 Control 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 implementation of components and control components, presentations are based on the corresponding circuit diagram symbols, it also introduced ready made circuit diagram symbols.
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 the 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 components. Hydraulic circuit carried out not only to deal with numbers, but also to deal with the actual device ID, in order to detect system failures.
DIN ISO1219-2 standard definition of the number of component composition, which includes 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 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 control loop are the corresponding number with the system.
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. 2, light weight, small size, small inertia, fast response.
3, to facilitate manipulation of control, enabling a wide range of stepless speed regulation (speed range of 2000:1).
4, to achieve overload 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 easy to achieve the automation of machines, when the joint control of the use of electro-hydraulic, not only can achieve a higher degree of process automation, and remote control can be achieved.
The shortcomings of the hydraulic system:
1, as a result 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 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, due to the leakage of liquid medium and the compressibility and can not be strictly the transmission ratio.
5, hydraulic transmission is not easy to find out the reasons for failure; the use and maintenance requirements for a higher level of technology.
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. Microinvasive 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 components. 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 (ie, sealed lips) two.
The three hydraulic system diseases
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 liquids 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 extern
收藏