【正文】 the external local oscillator on the system. 振動 液壓系統(tǒng)的振動也是其痼疾之一。 5, hydraulic transmission is not easy to find out the reasons for failure。 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。 Auxiliary ponents, including fuel tanks, oil filters, tubing and pipe joints, seals, pressure gauge, oil level, such as oil dollars. 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。 iron and steel indu stry metallurgical machinery, lifting equipment, such as roller adjustment device。s first hydraulic press. Media work in 1905 will be replaced by oilwater and further improved. 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,17491814)，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)。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。 flow control valves including throttle, adjusting the valves, flow diversion valve sets, etc.。 Basic hydraulic circuit of the action sequence Control ponents (two fourway valve) and the spring to reset for the implementation of ponents (doubleacting hydraulic cylinder), as well as the extending and retracting the relief valve opened and closed . For the implementation of ponents and control ponents, presentations are based on the corresponding circuit diagram symbols, it also introduced ready made circuit diagram symbols. 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閥的開啟和關(guān)閉。 5 The shortings of the hydraulic system: 液壓系統(tǒng)的缺點(diǎn)： 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. 由于流體流動的阻力和泄露較大，所以效率較低。 The three hydraulic system diseases 液壓系統(tǒng)的三 大頑疾 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 sam e time there is friction between the inner wall, which are a result of hydraulic the reasons for the oil tempera ture. Temperature will lead to increased internal and external leakage, reducing its mechanical efficiency. At the same time as a result of high temperature, hydraulic oil expansion will occur, resulting in increased pression, so that action can not be very good control of transmission. Solution: heat is the inherent characte ristics of the hydraulic system, not only to minimize eradication. Use a good quality hydraulic oil, hydraulic piping arrangement should be avoided as far as possible the emergence of bend, the use of highquality pipe and fittings, hydraulic valves, etc. 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。泄漏到環(huán)境中的液壓油還有發(fā)生火災(zāi)的危險。 （ 2）調(diào)節(jié)和控制方式多樣化； (3) to further improve the regulation performance, increase the efficiency of the powertrain。 pneumatic ponents and electronic technology, to the intelligent direction of development。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。 Therefore, seals and sealing device is an important hydraulic equipment ponents. 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 selfsealstyle and selfstyled selftight seal (ie, sealed lips) two. 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。 4, to achieve overload protection automatically. 可自動實(shí)現(xiàn)過載保護(hù) 。 operative or hydraulic cylinder with hydraulic motors, according to the actual requirements of their choice. 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。 The role of dynamic ponents 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 f