Construction machinery has developed rapidly in recent years， the stock of rapid Large construction machinery market， the current localization rate is not high， mainly rely on imports and foreign enterprises in China， import substitution space is Miniaturization， miniaturization is the trend of development， product life is the main gap between domestic and foreign products， surface treatment technology and materials are the key points to improve the service life of the Construction machinery is the largest user of hydraulic products， accounting for 3% of the sales of the industry， the construction machinery market is Mechanical transmission and hydraulic mechanical transmission (except for hydraulic excavator) are the main methods used in construction Now， the transmission mode of hydraulic and electric power transmission also appears in the engineering machinery walking drive device， fully indicates that the development of science and technology in this field is a huge impetus to the role Compared with the pure mechanical and hydraulic transmission， hydraulic transmission of the main advantages is the regulation of convenience and layout flexibility， according to the needs of the morphology and the mechanical engineering conditions， the engine， a driving wheel， a working mechanism of each component is respectively arranged in the reasonable parts， engine work in scheduling any speed， transmission system can play a greater traction and transmission system in a wide range of output speed can still maintain a high efficiency， and easy access to a variety of optimization of power transmission characteristics to adapt to the load state of the various With the combination of electronic technology and hydraulic technology， it can be very easy to achieve a variety of hydraulic system of regulation and The introduction of computer control and the application of all kinds of sensors， but also greatly expanded the scope of the work of hydraulic Through the sensor to monitor the engineering vehicle state parameters， through the computer output control target instruction， the vehicle automatic control is achieved in the whole operating range， machine of the fuel economy， power and productivity of reached optimum Therefore， the use of hydraulic transmission can make the construction machinery easy to realize intelligent， energy saving and environmental protection， and this has become the current and future development trend of construction Due to the development of modern science and technology， electronic technology in the signal processing ability and speed of occupy a great And the hydraulic and electric drive in their respective power components in terms of the characteristics of their own Therefore， in addition to the now ubiquitous "electronic nerve and hydraulic muscle" of this model， both in terms of power flow transmission composite also many successful examples， such as: composed of conversion or DC motor speed control and high efficiency and low ripple quantitative hydraulic pump variable flow hydraulic oil source， with the installation of the integrated electric pump hydraulic cylinder or low speed high torque hydraulic motor which is the electric hydraulic execution unit， and a hybrid industrial vehicle drive 工程机械近年来发展迅猛，存量迅速增长。庞大的工程机械主机配套市场，目前国产化率不高，主要依赖进口及在华外资企业，进口替代空间巨大。小型化、微型化是发展趋势、产品寿命是国内外产品的主要差距、表面处理工艺和材料是提高产品使用寿命关键点。工程机械是液压产品的最大用户，占行业销售的3%，为工程机械配套市场巨大。 工程机械行走系统最初主要采用机械传动和液力机械传动(全液压挖掘机除外)方式。现在，液压和电力传动的传动方式也出现在工程机械行走驱动装置中，充分表明了科学技术发展对这一领域的巨大推动作用。 与纯机械和液力传动相比，液压传动的主要优点是其调节的便捷性和布局的灵活性，可根据工程机械的形态和工况的需要，把发动机、驱动轮、工作机构等各部件分别布置在合理的部位，发动机在任一调度转速下工作，传动系统都能发挥出较大的牵引力，而且传动系统在很宽的输出转速范围内仍能保持较高的效率，并能方便地获得各种优化的动力传动特性，以适应各种作业的负荷状态。 借助电子技术与液压技术的结合，可以很方便地实现对液压系统的各种调节和控制。而计算机控制的引入和各类传感元件的应用，更极大地扩展了液压元件的工作范围。通过传感器监测工程车辆各种状态参数，经过计算机运算输出控制目标指令，使车辆在整个工作范围内实现自动化控制，机器的燃料经济性、动力性、作业生产率均达到最佳值。因此，采用液压传动可使工程机械易于实现智能化、节能化和环保化，而这已成为当前和未来工程机械的发展趋势。 由于现代技术的发展，电子技术在信号处理的能力和速度方面占有很大的优势，而液压与电力传动在各自功率元件的特性方面各有所长。因此，除了现在已普遍存在的“电子神经+液压肌肉”这种模式外，两者在功率流的复合传输方面也有许多成功的实例，如:由变频或直流调速电机和高效、低脉动的定量液压泵构成的可变流量液压油源，用集成安装的电动泵-液压缸或低速大扭矩液压马达构成的电动液压执行单元，以及混合动力工业车辆的驱动系统等。
Hydraulic fluids are a large group of fluids used as the motive medium in hydraulic Fluid types include synthetic compounds， mineral oil， water， and water-based The fluids are found in machinery and equipment ranging from brakes， power steering systems， and transmissions to backhoes， excavators， garbage trucks and industrial Hydraulic systems are very common in aircraft flight control Hydraulic systems like the ones mentioned above will work most efficiently if the hydraulic fluid used has low Because industrial hydraulic systems operate at hundreds to thousands of PSI and temperatures reaching hundreds of degrees Celsius， severe injuries and death can result from component failures and care must always be taken when performing maintenance on hydraulic Fire resistance is a property available with specialized The use of hydraulic systems in aircraft almost certainly began with braking [citation needed] As aircraft performance increased in mid-20th century， the amount of force required to operate mechanical flight controls became excessive， and hydraulic systems were introduced to reduce pilot The hydraulic actuators are controlled by valves; these in turn are operated directly by input from the aircrew (hydro-mechanical) or by computers obeying control laws (fly by wire) See flight Hydraulic power is used for other It can be stored in accumulators to start an auxiliary power unit (APU) for self-starting the aircraft's main Many aircraft equipped with the M61 family of cannon use hydraulic power to drive the gun system， permitting reliable high rates of The hydraulic power itself comes from pumps driven by the engines directly， or by electrica
什么是液压？ 一个完整的液压系统由五个部分组成，即动力元件、执行元件、控制元件、无件和液压油。动力元件的作用是将原动机的机械能转换成液体的压力能，指液压系统中的油泵，它向整个液压系统提供动力。液压泵的结构形式一般有齿轮泵、叶片泵和柱塞泵。执行元件(如液压缸和液压马达)的作用是将液体的压力能转换为机械能，驱动负载作直线往复运动或回转运动。 控制元件(即各种液压阀)在液压系统中控制和调节液体的压力、流量和方向。根据控制功能的不同，液压阀可分为村力控制阀、流量控制阀和方向控制阀。压力控制阀又分为益流阀(安全阀)、减压阀、顺序阀、压力继电器等；流量控制阀包括节流阀、调整阀、分流集流阀等；方向控制阀包括单向阀、液控单向阀、梭阀、换向阀等。根据控制方式不同，液压阀可分为开关式控制阀、定值控制阀和比例控制阀。 辅助元件包括油箱、滤油器、油管及管接头、密封圈、压力表、油位油温计等。 液压油是液压系统中传递能量的工作介质，有各种矿物油、乳化液和合成型液压油等几大类。 液压的原理 它是由两个大小不同的液缸组成的，在液缸里充满水或油。充水的叫“水压机”；充油的称“油压机”。两个液缸里各有一个可以滑动的活塞，如果在小活塞上加一定值的压力，根据帕斯卡定律，小活塞将这一压力通过液体的压强传递给大活塞，将大活塞顶上去。设小活塞的横截面积是S1，加在小活塞上的向下的压力是F1。于是，小活塞对液体的压强为P=F1/SI， 能够大小不变地被液体向各个方向传递”。大活塞所受到的压强必然也等于P。若大活塞的横截面积是S2，压强P在大活塞上所产生的向上的压力F2=PxS2 截面积是小活塞横截面积的倍数。从上式知，在小活塞上加一较小的力，则在大活塞上会得到很大的力，为此用液压机来压制胶合板、榨油、提取重物、锻压钢材等。 液压传动的发展史 液压传动和气压传动称为流体传动，是根据17世纪帕斯卡提出的液体静压力传动原理而发展起来的一门新兴技术，1795年英国约瑟夫•布拉曼(Joseph Braman，1749-1814)，在伦敦用水作为工作介质，以水压机的形式将其应用于工业上，诞生了世界上第一台水压机。1905年将工作介质水改为油，又进一步得到改善。 第一次世界大战(1914-1918)后液压传动广泛应用，特别是1920年以后，发展更为迅速。液压元件大约在 19 世纪末 20 世纪初的20年间，才开始进入正规的工业生产阶段。1925 年维克斯(FVikers)发明了压力平衡式叶片泵，为近代液压元件工业或液压传动 的逐步建立奠定了基础。20 世纪初康斯坦丁•尼斯克(G•Constantimsco)对能量波动传递所进行的理论及实际研究;1910年对液力传动(液力联轴节、液力变矩器等)方面的贡献，使这两方面领域得到了发展。 第二次世界大战(1941-1945)期间，在美国机床中有30%应用了液压传动。应该指出，日本液压传动的发展较欧美等国家晚了近 20 多年。在 1955 年前后 ， 日本迅速发展液压传动，1956 年成立了“液压工业会”。近20~30 年间，日本液压传动发展之快，居世界领先地位。 液压传动有许多突出的优点，因此它的应用非常广泛，如一般工。业用的塑料加工机械、压力机械、机床等；行走机械中的工程机械、建筑机械、农业机械、汽车等；钢铁工业用的冶金机械、提升装置、轧辊调整装置等；土木水利工程用的防洪闸门及堤坝装置、河床升降装置、桥梁操纵机构等；发电厂涡轮机调速装置、核发电厂等等；船舶用的甲板起重机械（绞车）、船头门、舱壁阀、船尾推进器等；特殊技术用的巨型天线控制装置、测量浮标、升降旋转舞台等；军事工业用的火炮操纵装置、船舶减摇装置、飞行器仿真、飞机起落架的收放装置和方向舵控制装置等。 What is Hydraulic? A complete hydraulic system consists of five parts， namely， power components， the implementation of components， control components， no parts and hydraulic 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 The structure of the form of hydraulic pump gears are generally pump， vane pump and piston 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 Control components (that is， the various hydraulic valves) in the hydraulic system to control and regulate the pressure of liquid， flow rate and According to the different control functions， hydraulic valves can be divided into the village of force control valve， flow control valves and directional control Pressure control valves are divided into benefits flow valve (safety valve)， pressure relief valve， sequence valve， pressure relays， ; flow control valves including throttle， adjusting the valves， flow diversion valve sets， ; directional control valve includes a one-way valve ， one-way fluid control valve， shuttle valve， valve and so 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 Auxiliary components， including fuel tanks， oil filters， tubing and pipe joints， seals， pressure gauge， oil level， such as oil 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 Hydraulic principle It consists of two cylinders of different sizes and composition of fluid in the fluid full of water or Water is called "hydraulic press"; the said oil-filled "hydraulic " 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 Based cross-sectional area of the small piston is S1， plus a small piston in the downward pressure on the F Thus， a small piston on the liquid pressure to P = F1/SI， Can be the same size in all directions to the transmission of "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 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 History of the development of hydraulic 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 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 Media work in 1905 will be replaced by oil-water and further World War I (1914-1918) after the extensive application of hydraulic transmission， especially after 1920， more rapid Hydraulic components in the late 19th century about the early 20th century， 20 years， only started to enter the formal phase of industrial 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 The early 20th century Constantine (G • Constantimsco) fluctuations of the energy carried out by passing theoretical and practical research; in 1910 on the hydraulic transmission (hydraulic coupling， hydraulic torque converter， ) contributions， so that these two areas of The Second World War (1941-1945) period， in the United States 30% of machine tool applications in the hydraulic 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 Before and after in 1955， the rapid development of Japan's hydraulic drive， set up in 1956， "Hydraulic I" Nearly 20 to 30 years， the development of Japan's fast hydraulic transmission， a world Hydraulic transmission There are many outstanding advantages， it is widely used， such as general Plastic processing industry， machinery， pressure machinery， machine tools， ; operating machinery engineering machinery， construction machinery， agricultural machinery， automobiles， ; iron and steel industry metallurgical machinery， lifting equipment， such as roller adjustment device; civil water projects with flood control the dam gates and devices， bed lifts installations， bridges and other manipulation of institutions; speed turbine power plant installations， nuclear power plants， ; ship deck crane (winch)， the bow doors， bulkhead valves， such as the stern thruster ; special antenna technology giant with control devices， measurement buoys， movements such as rotating stage; military-industrial control devices used in artillery， ship anti-rolling devices， aircraft simulation， aircraft retractable landing gear and rudder control devices and other
