液压系统外文文献翻译、中英文翻译、外文翻译

湖南工学院本科毕业设计（论文）

外文译文

院 （系）： 机械工程学院 专 业： 机械设计制造及其自动化 姓 名： 程艳波 学 号： 08201420736

指导教师评语： 签名： 年 月 日

译文：

液压系统

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(F.Vikers)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。

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、辅助元件和液压油。

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，液压阀可分为压力控制阀、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。

液压系统的作用就是帮助人类做工。主要是由执行元件把压力变成转动或往复运动。

液压系统由信号控制和液压动力两部分组成，信号控制部分用于驱动液压动力部分中的控制阀动作。

液压动力部分采用回路图方式表示，以表明不同功能元件之间的相互关系。液压源含有液压泵、电动机和液压辅助元件；液压控制部分含有各种控制阀，其用于控制工作油液的流量、压力和方向；执行部分含有液压缸或液压马达，其可按实际要求来选择。

在分析和设计实际任务时，一般采用方框图显示设备中实际运行状况。 空心箭头表示信号流，而实心箭头则表示能量流。

基本液压回路中的动作顺序—控制元件（二位四通换向阀）的换向和弹簧复位、执行元件（双作用液压缸）的伸出和回缩以及溢流阀的开启和关闭。 对于执行元件和控制元件，演示文稿都是基于相应回路图符号，这也为介绍回路图符号作了准备。

根据系统工作原理，您可对所有回路依次进行编号。如果第一个执行元件编号为0，则与其相关的控制元件标识符则为1。如果与执行元件伸出相对应的元件标识符为偶数，则与执行元件回缩相对应的元件标识符则为奇数。 不仅应对液压回路进行编号，也应对实际设备进行编号，以便发现系统故障。

DIN ISO1219-2标准定义了元件的编号组成，其包括下面四个部分：设备编号、回路编号、元件标识符和元件编号。如果整个系统仅有一种设备，则可省略设备编号。

实际中，另一种编号方式就是对液压系统中所有元件进行连续编号，此时，元件编号应该与元件列表中编号相一致。 这种方法特别适用于复杂液压控制系

统，每个控制回路都与其系统编号相对应

与机械传动、电气传动相比，液压传动具有以下优点：

1、液压传动的各种元件，可以根据需要方便、灵活地来布置。 2、重量轻、体积小、运动惯性小、反应速度快。

3、操纵控制方便，可实现大范围的无级调速（调速范围达2000：1）。 4、可自动实现过载保护。

5、一般采用矿物油作为工作介质，相对运动面可自行润滑，使用寿命长；

6、很容易实现直线运动/

7、很容易实现机器的自动化，当采用电液联合控制后，不仅可实现更高程度的自动控制过程，而且可以实现遥控。

液压系统的缺点：

1、由于流体流动的阻力和泄露较大，所以效率较低。如果处理不当，泄露不仅污染场地，而且还可能引起火灾和爆炸事故。

2、由于工作性能易受到温度变化的影响，因此不宜在很高或很低的温度条件下工作。

3、液压元件的制造精度要求较高，因而价格较贵。

4、由于液体介质的泄露及可压缩性影响，不能得到严格的传动比。 5、液压传动出故障时不易找出原因；使用和维修要求有较高的技术水平。 在液压系统及其系统中，密封装置用来防止工作介质的泄漏及外界灰尘和异物的侵入。其中起密封作用的元件，即密封件。外漏会造成工作介质的浪费，污染机器和环境，甚至引起机械操作失灵及设备人身事故。内漏会引起液压系统容积效率急剧下降，达不到所需要的工作压力，甚至不能进行工作。侵入系统中的微小灰尘颗粒，会引起或加剧液压元件摩擦副的磨损，进一步导致泄漏。

因此，密封件和密封装置是液压设备的一个重要组成部分。它的工作的可靠性和使用寿命，是衡量液压系统好坏的一个重要指标。除间隙密封外，都是利用密封件，使相邻两个偶合表面间的间隙控制在需要密封的液体能通过的最小间隙以下。在接触式密封中，分为自封式压紧型密封和自封式自紧型密封（即唇形密封）两种。

液压系统的三大顽疾

1、发热 由于传力介质（液压油）在流动过程中存在各部位流速的不同，导致液体内部存在一定的内摩擦，同时液体和管路内壁之间也存在摩擦，这些都是导致液压油温度升高的原因。温度升高将导致内外泄漏增大，降低其机械效率。同时由于较高的温度，液压油会发生膨胀，导致压缩性增大，使控制动作无法很好的传递。解决办法：发热是液压系统的固有特征，无法根除只能尽量减轻。使

用质量好的液压油、液压管路的布置中应尽量避免弯头的出现、使用高质量的管路以及管接头、液压阀等。

2、振动 液压系统的振动也是其痼疾之一。由于液压油在管路中的高速流动而产生的冲击以及控制阀打开关闭过程中产生的冲击都是系统发生振动的原因。强的振动会导致系统控制动作发生错误，也会使系统中一些较为精密的仪器发生错误，导致系统故障。解决办法：液压管路应尽量固定，避免出现急弯。避免频繁改变液流方向，无法避免时应做好减振措施。整个液压系统应有良好的减振措施，同时还要避免外来振源对系统的影响。

3、泄漏 液压系统的泄漏分为内泄漏和外泄漏。内泄漏指泄漏过程发生在系统内部，例如液压缸活塞两边的泄漏、控制阀阀芯与阀体之间的泄漏等。内泄漏虽然不会产生液压油的损失，但是由于发生泄漏，既定的控制动作可能会受到影响，直至引起系统故障。外泄漏是指发生在系统和外部环境之间的泄漏。液压油直接泄漏到环境中，除了会影响系统的工作环境外，还会导致系统压力不够引发故障。泄漏到环境中的液压油还有发生火灾的危险。解决办法：采用质量较好的密封件，提高设备的加工精度。

另：对于液压系统这三大顽疾，有人进行了总结：“发烧、拉稀带得瑟”（这位总结者是东北人）。液压系统用于升降机，挖掘机，泵站，强夯机，起重机，等等大型工业，建筑，工厂，企业，还有升降机，升降平台，登车桥等等行业。

液压元件将向高性能、高质量、高可靠性、系统成套方向发展；向低能耗、低噪声、振动、无泄漏以及污染控制、应用水基介质等适应环保要求方向发展；开发高集成化高功率密度、智能化、机电一体化以及轻小型微型液压元件；积极采用新工艺、新材料和电子、传感等高新技术。

---- 液力偶合器向高速大功率和集成化的液力传动装置发展，开发水介质调速型液力偶合器和向汽车应用领域发展，开发液力减速器，提高产品可靠性和平均无故障工作时间；液力变矩器要开发大功率的产品，提高零部件的制造工艺技术，提高可靠性，推广计算机辅助技术，开发液力变矩器与动力换档变速箱配套使用技术；液粘调速离合器应提高产品质量，形成批量，向大功率和高转速方向发展。

气动行业：

----产品向体积小、重量轻、功耗低、组合集成化方向发展，执行元件向种类多、结构紧凑、定位精度高方向发展；气动元件与电子技术相结合，向智能化方向发展；元件性能向高速、高频、高响应、高寿命、耐高温、耐高压方向发展，普遍采用无油润滑，应用新工艺、新技术、新材料。

（1）采用的液压元件高压化，连续工作压力达到40Mpa，瞬间最高压力达

等等大型工业，建筑，工厂，企业，还有升降机，升降平台，登车桥等等行业。

液压元件将向高性能、高质量、高可靠性、系统成套方向发展；向低能耗、低噪声、振动、无泄漏以及污染控制、应用水基介质等适应环保要求方向发展；开发高集成化高功率密度、智能化、机电一体化以及轻小型微型液压元件；积极采用新工艺、新材料和电子、传感等高新技术。

---- 液力偶合器向高速大功率和集成化的液力传动装置发展，开发水介质调速型液力偶合器和向汽车应用领域发展，开发液力减速器，提高产品可靠性和平均无故障工作时间；液力变矩器要开发大功率的产品，提高零部件的制造工艺技术，提高可靠性，推广计算机辅助技术，开发液力变矩器与动力换档变速箱配套使用技术；液粘调速离合器应提高产品质量，形成批量，向大功率和高转速方向发展。

气动行业：

----产品向体积小、重量轻、功耗低、组合集成化方向发展，执行元件向种类多、结构紧凑、定位精度高方向发展；气动元件与电子技术相结合，向智能化方向发展；元件性能向高速、高频、高响应、高寿命、耐高温、耐高压方向发展，普遍采用无油润滑，应用新工艺、新技术、新材料。

（1）采用的液压元件高压化，连续工作压力达到40Mpa，瞬间最高压力达到48Mpa；

（2）调节和控制方式多样化；

（3）进一步改善调节性能，提高动力传动系统的效率；

（4）发展与机械、液力、电力传动组合的复合式调节传动装置； （5）发展具有节能、储能功能的高效系统； （6）进一步降低噪声；

（7）应用液压螺纹插装阀技术，紧凑结构、减少漏油。

原文：

Foreign language translation

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, espec- ially 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 develo- pment.

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, \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 industr- ial 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 flo- od 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, measu- rement 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 devi- ces.

A complete hydraulic system consists of five parts, namely, power components, the implementation of co- mponents, 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 hydra- ulic pump gears are generally pump, vane pump and piston pump.

Implementation of components (such as hydraulic cylinders and hydraulic motors) which isthe 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 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 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 equi - pment. 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. Micro-invasive 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 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 com- 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 high-quality pipe and fittings, hydraulic valves, etc.

2, the vibration of the vibration of the hydraulic system is also one of its malaise. As a result of hydraulic oil in the pipeline flow of high-speed impact and the control valve to open the closure of the impact of the process are the reasons for the vibration system. Strong vibration control action will cause the system to error, the system will also be some of the more sophisticated equipment error, resulting in system failures. Solutions: hydraulic pipe should be fixed to avoid sharp bends. To avoid frequent changes in flow direction, can not avoid damping measures should be doing a good job. The entire hydraulic system should have a good damping measures, while avoiding the external local oscillator on the system.

3, the leakage of the hydraulic system leak into inside and outside the leakage leakage. Leakage refers to the process with the leak occurred in the system, such as hydraulic

piston-cylinder on both sides of the leakage, the control valve spool and valve body, such as between the leakage. Although no internal leakage of hydra- ulic fluid loss, but due to leakage, the control of the established movements may be affected until the cause system failures. Outside means the occurrence of leakage in the system and the leakage between the external environment. Direct leakage of hydraulic oil into the environment, in addition to the system will affect the working environment, not enough pressure will cause the system to trigger a fault. Leakage into the enviro- nment of the hydraulic oil was also the danger of fire. Solution: the use of better quality seals to improve the machining accuracy of equipment.

Another: the hydraulic system for the three diseases, it was summed up: \with a father拉稀\for the lifts, excavators, pumping station, dynamic, crane, and so on large-scale industry, construction, factories, enterprises, as well as elevators, lifting platforms, Deng Axle industry and so on.

Hydraulic components will be high-performance, high-quality, high reliability, the system sets the direction of development; to the low power, low noise, vibration, without leakage, as well as pollution control, water-based media applications to adapt to environmental requirements, such as the direction of development; the

development of highly integrated high power density, intelligence, mechatronics and micro-light mini-hydraulic components; active use of new techniques, new materials and electronics, sensing and other high-tech.

---- Hydraulic coupling to high-speed high-power and integrated development of hydraulic transmission equ- ipment, development of water hydraulic coupling medium speed and the field of automotive applications to develop hydraulic reducer, improve product reliability and working hours MTBF; hydraulic torque converter to the development of high-power products, parts and components to improve the manufacturing process tech -nology to improve reliability, promote computer-aided technology, the development of hydraulic torque con- verter and power shift transmission technology supporting the use of ; Clutch fluid viscosity should increase the quality of products, the formation of bulk to the high-power and high-speed direction. Pneumatic Industry:

---- Products to small size, light weight, low power consumption, integrated portfolio of development, the implementation of the various types of components, compact structure, high positioning accuracy of the direction of development; pneumatic components and electronic technology, to the intelligent direction of development; component performance to high-speed, high-frequency, high-response, high-life, high temp- erature, high voltage direction, commonly used oil-free lubrication, application of new technology, new technology and new materials.

(1) used high-pressure hydraulic components and the pressure of continuous work to reach 40Mpa, the maximum pressure to achieve instant 48Mpa; (2) diversification of regulation and control;

(3) to further improve the regulation performance, increase the efficiency of the

powertrain;

(4) development and mechanical, hydraulic, power transmission of the composite portfolio adjustment gear;

(5) development of energy saving, energy efficient system function; (6) to further reduce the noise;

(7) Application of Hydraulic Cartridge Valves thread technology, compact structure, to reduce the oil spill.

A, hydraulic system

Only the following three basic methods to transfer power: electrical, mechanical and fluid. Most of the application system is actually will be three methods together and get the most effective the most comprehensive system. In order to properly determine what kinds of methods, the important thing is to know the salient features of the various methods. Such as hydraulic system in long distance than mechanical system can transfer more economic power. However hydraulic system and electrical system, transfer of power than distance is short.

Hydraulic power transmission system involving motor, adjusting device, pressure and flow control, on the whole, this system includes:

1. The pump: will the dynamic role in executive ability converted into parts of the hydraulic can.

2. Valve: control pump produced fluid movement direction and the power of the size, and to perform component of the liquid flow. Power depends on the size of the flow rate and pressure control.

3. Executive parts: will hydraulic converted into usable mechanical energy. 4. Medium that is of no oil: can be compressed transfer and control, and at the same time can make body sealing parts, lubrication and cooling system.

5. Connection thing: each system components, for connection to provide power transmission fluid pressure, the liquid tank access to return to the fuel storage device .

6. The oil storage and adjusting device: to ensure that provide sufficient quality and quantity and cooling liquid.

Hydraulic system is widely used in industry, such as stamping, steel class of grinding workpiece and the general processing, agricultural machinery, mining, space technology, deep sea exploration, transportation, Marine technology, offshore gas and oil exploration industry, in short, in daily life few people don't get some from hydraulic technology benefits. Hydraulic system success and the extensive use of secret lies in its general and practical. Hydraulic power

transmission wouldn't be as mechanical system that the restriction of the geometrical form by machine, in addition, hydraulic system won't like electrical system by the physical properties of the material that restrict, it to transfer power almost no amount of restrictions. For example, an

electromagnet performance by steel magnetic saturation limit, instead, hydraulic system limit the power of the subject only to the material strength limit.

Enterprise in order to improve productivity will depend more and more on automation, including the remote control and direct the production operation, processing and material handling, etc. Hydraulic power became an important part of automation, because it has the following advantages: the four main

1. The precise convenient control by operating a simple joystick and buttons, the operators of the hydraulic system and can immediately start, stop, and deceleration and can provide any power, position precision for one over ten thousand inch position control. A make the pilot rises and fall the landing gear on the hydraulic system, when the pilot to a certain direction control valves, pressure oil into hydraulic cylinder of a cavity and came down on the landing gear. The pilot to move in the opposite direction control valves, allow the oil into the hydraulic cylinder of another chamber to take back on the landing gear.

2. Add force a hydraulic system (without the use of heavy gear wheel, pulley and lever) can easily and efficiently will not an ounce of force-magnifying produce hundreds of tons of force output.

3. Constant force and constant torque can provide not only the hydraulic system with the speed of change and change is constant force or constant torque, it can drive the object from a few inches per hour to move every minute, every hour hundreds of inches from a few turned to every minute thousands of turn.

4. Simple, safe, economic overall, hydraulic system mechanical or electrical system than with fewer moving parts, therefore, they operation and convenient maintenance. This makes the system structure is compact, safe and reliable. For example, a new type of vehicle for power steering control device has been eliminated other types of steering power plant, this steering parts are included in the human control direction control valves and distributors. Due to the parts is full hydraulic pressure, no universal joint, bearing, the reduction gear, etc, this makes mechanical connection simple and compact system.

In addition, enter a small torque can produce very bad working conditions to meet the control, the operation due to space restrictions and need small the steering wheel is very important occasions, this also is necessary to reduce the driver fatigue.

Hydraulic system of other advantages including two-way movement, overload protection and stepless speed control, in the existing system of any power hydraulic system also has the largest unit quality power than.

Although hydraulic system has such a high performance, but it is not can solve all problems power transfer the panacea. Hydraulic system also some disadvantages, hydraulic oil have pollution, and leakage can't completely avoid, and if the oil leakage occurred in hot equipment, most of the hydraulic oil near can cause a fire.

Two pressure system

Air pressure system pressure gas transmission and is used to control the power, as the name of that show, air pressure system usually use air (no other gas) as a liquid medium, because the air is security, low cost and widely available, the fluid in the system components may produce electric arc light leakage of the situation that USES air as medium (especially safety.

In the air pressure system, compressor used to compress and the air supply. Compressor usually have a piston, vane and spiral type etc. Compressor is basically according to law, the ideal gas by reducing the volume of a gas to increase gas pressure. Pneumatic system usually consider using a big central air compressor as an unlimited amount of gas source, it's sort of like in the power system, as long as the plug in the socket will get electricity. Using this method, the gas pressure from transported to the whole factory air each corners of the gas pressure, through the air filter remove filth, these dirt may be damaged pneumatic components of precision components such as with valve and cylinder, then transported to each loop, and the air flowing through in order to decrease the pressure reducing valve is suitable for that one way to use. Because the air is not good lubricants (including 20% oxygen), air pressure system needs a oil sprayer the tiny oil mist injection pressure reducing valve to after air, which could help reduce the pneumatic components with exercise wear a precision.

Because of different from atmospheric air quantity of moisture, the water is harmful, and it can take away lubricant cause excessive wear and corrosion, therefore, in some situations, to use with air dryer to remove these harmful moisture. Due to atmospheric pressure system directly from too much, can produce noise, so it can vent

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