【正文】 he work of media within and outside the dust and the intrusion of foreign bodies. Seals played the role of ponents, 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 ponent wear, and further lead to leakage. 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。 5, hydraulic transmission is not easy to find out the reasons for failure。 3, the manufacture of precision hydraulic ponents require a higher, more expensive and hence the price. 液壓元件的制造精度要求較高，因而價(jià)格較貴。如果處理不當(dāng)，泄露不僅污染場(chǎng)地，而且還可能引起火災(zāi)和爆炸事故。 很容易實(shí)現(xiàn)機(jī)器的自動(dòng)化，當(dāng)采用電液聯(lián)合控制后，不僅可實(shí)現(xiàn)更高程度的自動(dòng)控制過程，而且可以實(shí)現(xiàn)遙控 。 5, the general use of mineral oil as a working medium, the relative motion can be selflubricating surface, long service life。 3, to facilitate manipulation of control, enabling a wide range of stepless speed regulation (speed range of 2021:1). 操縱控制方便，可實(shí)現(xiàn)大范圍的無級(jí)調(diào)速（調(diào)速范圍達(dá) 2021： 1）。 這種方法特別適用于復(fù)雜液壓控制系統(tǒng)，每個(gè)控制回路都與其系統(tǒng)編號(hào)相對(duì)應(yīng) With mechanical transmission, electrical transmission pared to the hydraulic drive has the following advantages: 與機(jī)械傳動(dòng)、電氣傳動(dòng)相比，液壓傳動(dòng)具有以下優(yōu)點(diǎn)： 1, a variety of hydraulic ponents, can easily and flexibly to layout. 液壓傳動(dòng)的各種元件，可以根據(jù)需要方便、靈活地來布置。如果整個(gè)系統(tǒng)僅有一種設(shè)備，則可省略設(shè)備編號(hào)。 不僅應(yīng)對(duì)液壓回路進(jìn)行編號(hào)，也應(yīng)對(duì)實(shí)際設(shè)備進(jìn)行編號(hào)，以便發(fā)現(xiàn)系統(tǒng)故障。如果第一個(gè)執(zhí)行元件編號(hào)為 0，則與其相關(guān)的控制元件標(biāo)識(shí)符則為 1。 對(duì)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(hào)，這也為介紹回路圖符號(hào)作了準(zhǔn)備。 空心箭頭表示信號(hào)流，而實(shí)心箭頭則表示能量流。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。 hydraulic control part contains a variety of control valves, used to control the flow of oil, pressure and direction。 Hydraulic system and hydraulic power control signal is posed of two parts, the signal control of some parts of the hydraulic power used to drive the control valve movement. 液壓系統(tǒng)由信號(hào)控制和液壓動(dòng)力兩部分組成，信號(hào)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。 The role of the hydraulic system is to help humanity work. Mainly by the implementation of ponents to rotate or pressure into a reciprocating motion. 液壓系統(tǒng)的作用就是幫助人類做工。 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。壓力控制閥又分為益流閥 (安全閥 )、減壓 3 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。 directional control valve includes a oneway valve , oneway 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. 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。 Control ponents (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.。液壓泵的結(jié)構(gòu)形式一般有齒輪泵、葉片泵和柱塞泵。 A plete hydraulic system consists of five parts, namely, power ponents, the implementation of co mponents, control ponents, auxiliary ponents and hydraulic oil. 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。 special antenna technology giant with control devices, measu rement buoys, movements such as rotating stage。 speed turbine power plant installations, nuclear power plants, etc.。 iron and steel indu stry metallurgical machinery, lifting equipment, such as roller adjustment device。 Hydraulic transmission There are many outstanding advantages, it is widely used, such as