液压系统外文翻译
液压系统的形式及评价外文翻译
The hydraulic presses system of the form and the evaluationThe hydraulic presses the component to carried out to standardize gradually, the series turn, its specification, species, quantity, functionses all had to raise very greatly, particularly is to adopt the new craft of new technique of electronics technique, servo technique...etc. after, the hydraulic presses the exaltation that the quantity of the system gets to show the highest , it developped the important function in national economy and the military industries.Set out from the different angle, can press the system to the liquid to be divided into the different form.1）Press the circulating way of the oil liquid, the liquid press the system and can is divided into the open type system and shut type systems.The open type system mean that the liquid presses the pump to absorb the oil from the fuel tank, the oil is through various control valve, driving the liquid to press to carry out the component, returning to oil to has been changed to return to fuel tank toward valve again.This kind of system structure is more simple, can develop the fuel tank to spread hot, precipitate the miscellaneous quality function, but often get in touch with with air because of the oil liquid, make air be easy to seep into the system, causing the organization exercise the gravamen steady etc. result.The open type system fuel tank is big, oil pump from absorb the function and like.In the shut type system, the liquid presses the pump of into pipeline directly with performance the component return to pipeline connect with each other, work the liquid carries on closing the circulation in the tube road of the system.Its structure tightly packed, with the air opportunity to get in touch with little, not easy infiltration system of air, so spread to move more steady.The work organization become soon and change to depend to regulate the pump or motors to change to measure the organization realization, avoided the open type system change toward process appear of liquid press the impact and energy losses.But the shut type system more the open type system complications, because of having no fuel tank, the oil liquid spread hot and filter the condition is worse.In order to compensate the leakiness in the system, usually need a small discharge to repair the oil pump and fuel tanks.Because the oil a size of a function of high bar discharge not etc., will make power make use of descend in work process, so the performance component within the shut type system presses the motor for the liquid generally.2）According to system the liquid presses the number of the pump, can is divided into the list pump system, double pump system and pump system more.3）Press the dissimilarity of pump the form with the liquid by, can is divided into the fixed amount pump system and change the quantity pump system.The advantage that changes to measure the pump is to regulate the scope inside, can make use of the power of launch the machine well, but its structure and the manufacturing craft complications, the cost is high, can is divided in to move to change the quantity, control to change the quantity possibly, servo change the quantity, pressure to compensate to change the quantity, press to change the quantity, liquid to press to change to measure various ways of etc..4)Press toward performance the component to provide the dissimilarity of the oil method, can is divided in to establish the system and merge the system.Establish in the system, it is next performance component that previous performance component return to oil of into oil, pass a performance component pressure and will lower once each time.In establish system, the each performance component that be the lord pump toward many roads valve control provides the oil,as long as the liquid presses the exit pressure of the pump enough, the compound of the sport that can carry out each performance component then.But the pressure of the performance component is to fold to add of, so overcome the outside carry ability will with carry out the increment of the component quantity but lower.Merge in the system, be a the pedestal liquid to press the pump toward a performance component to provide the oil, discharge that enters each performance component be just the liquid press the pump exportation discharge of a part.The allotment of the discharge with each last the outside carries the lotus of dissimilarity but variety, enter first outside carry the smaller performance component of lotus, only be each performance component up outside carry the lotus equality, then can carry out to act at the same time.The whole liquid presses to spread the good and bad of move the machine function, mainly being decided by the quality that the liquid presses the system function, including the component quantity good and bad use, basic back track whether fitting etc..The quality of the system function, in addition to satisfying to use the function to request, should make use of, adjust from the efficiency, power that the liquid press the system soon scope and tiny adjust characteristic, vibration and voice of noises and the gearing of the systems and adjust to try whether convenient credibility etc. carry on.The modern engineering machine almost adopts the liquid to press the system, and combine with electronics system, the calculator control technique, the importance that become the modern engineering machine constitutes the part.液压系统的形式及评价液压元件逐步实现了标准化、系列化，其规格、品种、质量、性能都有了很大提高，尤其是采用电子技术、伺服技术等新技术新工艺后，液压系统的质量得到了显著的提高，其在国民经济及军事工业中发挥了重大作用。
混凝土泵车液压系统的认识外文文献翻译、中英文翻译
译文原文：Understanding of concrete pump hydraulic systemItalian CIFA Concrete Machinery Company(1.CIFA concrete mechanical pump Institute, Italy)Pumping Hydraulic systemBoom hydraulic systemOutrigger hydraulic systemHydraulic system diagramDaily check and maintenance of the hydraulic systemThe functions of the truck mounted concrete pump, hydraulic system can be divided into pumping hydraulic system, boom hydraulic system, outrigger hydraulic system.Pumping Hydraulic system Is divided into three parts: main pumping system, distribution and lubricating system, mixing and cooling and cleaning system.Main pumping systemThere are two hydraulic loops: open and close loop.The Open loop: uses an A11VLO190 variable displacement of axial piston pump. It is fitted with a constant power control device, pressure cut-off valve and electricalstroke limiter with proportional solenoid. The constant power control device has been set in the factory. The displacement can be adjusted from 0 to Maximum by turning the oil pump displacement potentiometer on the control panel from low to high.Fig. 1 A11VLO 190A，B Service port (without charging pump) 420 barS Suction port (with charging pump) 35 barT1, T2 Air bleed, tankR Air bleed, oil drainM1 Measuring point, regulating chamberM Measuring point, service portG Port for positioning pressure (controller) for version with stroke limiter (H.., U2), HD and EP with screw ed fitting GE10 – PLM (otherwise port G closed)The other is the control line, which can change the flow direction and the displacement of main pump through constant power valve, proportional solenoid pressure reducing valve, directional control valve and servo valve of main pump.The Closed loop: There is an auxiliary pump with relief valve that the setting pressure is 3.5Mpa in A4VG180. The auxiliary pump has two output ways. One is the charge oil line, which connects with suction line of main pump through the check valve in two pressure relief valves and add oil to main pump. At the same time excessive hydraulic oil return to oil tank through flushing valve and cooler to realize heat exchange for closed loop.A, B Service line ports SAE 1 1/4", high pressure series 420 barT1 Case drain or filling portT2 Case drain M33×2; 18 deepM A, M B Pressure gauge - operating pressure A, BR Air bleedS Boost suction portX1, X2Control pressure ports (before the orifice)G Pressure port for auxiliary circuitP S Control pressure supplyFa Filter outletFa1Filter outlet (filter assembly)Fe Filter inlet M33×2; 18 deepF S Port from filter to suction line (cold start)M H Port for balanced high pressureY1, Y2Remote control ports (only for HD control)Flushing valveUsed for closed loop to prevent excessive heat build-up in closed circuit operation. The setting pressure of flushing valve is 3.0MPaPressure reducing valve with proportional solenoidUsed for closed loop. The Output pressure is connected with the remote control port of main pump to control the displacement and is controlled by a proportional current signal and constant power valve. The displacement can be adjusted from 0 to Maximum by turning the displacement adjusting potentiometer.Constant power valveUsed for closed loop. When the hydraulic system pressure is over the setting pressure, the valve works to reduce the output pressure of the pressure reducing valve and maintain the constant power.Pilot pressure setting Power settingFig.3 Constant power valveMain pump suction filterOpen loop: filtration fineness 100u.Close loop: filtration fineness 20u.When the indicator in the vacuum gauge exceeds the safe area or the electric signal instrument gives a warning, the cartridge may be blocked. It should be clean or replace filter cartridge promptly.Filter filtration fineness is 20u in open loop. When the reading pressure of the vacuum gauge exceeds 0.35Mpa, the cartridge may be blocked. It should be clean orReturn filterreplace filter cartridge promptly.Filter filtration fineness is 10u in closed loop. When the electricity deliver reports to the police, the cartridge may be blocked, it should be clean or replace filter cartridge promptly. Distribution and lubricating systemConstant pressure pumpSetting screw for pressurecontrol zero /Stroke pressureFig.4 Constant pressure pumpAn A10VO28 constant pump is used for the distribution system of supply oil.The setting of the pressure control valve of the pump is 16Mpa. Once the system pressure is reached,the bump will keep this pressure then decrease the displacement. There is a pressure relief valve in the distribution circuit to act as a safety valve, which is set to 18Mpa.Plate ball valve (shut-off valve)Used to discharge the accumulator. It must be rotated the lever of shut-off valve anti-clockwise when the pumping finishes or stopped for maintenance, in order to discharge the pressure of theaccumulator. (Pressure gauge of distribution system is zero) AccumulatorInflation pressure is 8-9Mpa. Use Only Nitrogen to fill the accumulator. Charging pressure should not exceed these figures.Lubricating systemThere are two types. One is reciprocating centralized lubrication that is driven by oil from the swing cylinders of distribution system includes lubricating single pump (or double pump), distributor, damper and filter. The other is automatic centralized lubrication that is driven by a D.C motor with an independent grease tank and independent from the hydraulic system. The interval time of lubrication is carried out in the factory. The lubrication system works automatically when pumping.Mixing, cooling, cleaning systemOnly the Mixing, cooling, cleaning system are driven by motor in open loop.Gear pumpGear pump supplies oil to the mixing, cooling, cleaning system.Sandwich type relief valveThe pressure is set to 14Mpa.Ressure relayIf the mixing blade is stuck, the system pressure will raise. When the pressure exceeds the setting value (usually 10Mpa), the pressure relay will give a warning. The Solenoid directional control valve changes direction to let the mixing motor to rotate anti-clockwise. After 6 second the solenoid valve will reset, and the mixing motor will rotate clockwise again. Return filterThe filtration fineness is 10u in closed loop. The cartridge may be blocked when the electric alarm sounds. It should be replace promptly.Boom hydraulic systemBoom pumpBoom and outrigger use the same pump.37m and 40m truck mounted concrete pumps: A2FO23 fixed displacement pump44m and 47m truck mounted concrete pumps: A7VO55LRDS variable displacement pump, or A7VO55DRS variable displacement pump46m and 49m truck mounted concrete pumps: A7VO55LRDS variable displacement pumpFig.5 A7VO55DRS Fig.6 A7VO55LRDS Fig.7 A2FO23 Boom proportional directional spool valveThe proportional directional spool valve with electro-hydraulic consists of pressure relief valve, pressure reducing valve, and flow control valve, and can becontrolled manual or by remote control.Fig.8 Boom proportional directional spool valveLoad-holding valveLoad-holding valve has three functions. (1) It acts as a lock when the cylinder isn’t moving. (2) Load-holding valve has twice relief function to protect boom against vibrating. It will be adjusted in the factory. (3) When the boom moves downward asSlewing load-holding valvegravity load, it can limit speed to prevent the boom falling too quickly and shaking.There are three main functions. Lock, overload protection and speed limiting. Outrigger hydraulic systemOutrigger hydraulic system and boom hydraulic system are used the same pump to supply oil. Outriggers should be set up before the boom is operated by the control levers or electric control button on both sides of the truck mounted concrete pump.Outrigger proportional directional spool valveIt is an integrated unit with a relief valve inside to control maximum pressure of the outrigger hydraulic system.Fig .9 Outrigger proportional directional spool valveOutrigger hydraulic lockIt is used to lock the outrigger cylinders and pay attention to the vertical moving of the outrigger cylinder when working .Pressure relief valve中文译文：混凝土泵车液压系统的认识意大利 CIFA 混凝土机械公司（1.CIFA 混凝土机械泵车研究所, 意大利，）泵送单元液压系统臂架液压系统 支腿液压系统 液压原理图液压系统的日常保养及维护泵车液压系统按泵车功能可划分为泵送单元液压系统、臂架液压系统、支腿液压系统。
液压中英文对照表
液压中英文对照：流体传动hydraulic power液压技术hydraulics液力技术hydrodynamics气液技术hydropneumatics运行工况operating conditions额定工况rated conditions极限工况limited conditions瞬态工况instantaneous conditions稳态工况steady-state conditions许用工况acceptableconditions连续工况continuous working conditions实际工况actual conditions效率efficiency旋转方向direction of rotation公称压力nominal pressure工作压力working pressure进口压力inlet pressure出口压力outlet pressure压降pressure drop；differential pressure背压back pressure启动压力breakout pressure充油压力charge pressure开启压力cracking pressure峰值压力peak pressure运行压力operating pressure耐压试验压力proof pressure冲击压力surge pressure静压力static pressure系统压力system pressure控制压力pilot pressure充气压力pre-charge pressure吸入压力suction pressure调压偏差override pressure额定压力rated pressure耗气量air consumption泄漏leakage内泄漏internal leakage外泄漏external leakage层流laminar flow紊流turbulent flow气穴cavitation 流量flow rate排量displacement额定流量rated flow供给流量supply flow流量系数flower factor滞环hysteresis图形符号graphical symbol液压气动元件图形符号symbols for hydraulic and pneumatic components流体逻辑元件图形符号symbols for fluid logic devices逻辑功能图形符号symbols for logic functions回路图circuit diagram压力－时间图pressure time diagram 功能图function diagram循环circle自动循环automatic cycle工作循环working cycle循环速度cycling speed工步phase停止工步dwell phase工作工步working phase快进工步rapid advance phase快退工步rapid return phase频率响应frequency response Hysterics 滞环Threshold 灵敏度Lap 滞后Pressure gain 压力增益Null 零位Null bias 零偏Null shift 零飘Frequency response 频率响应Slope 曲线斜坡液压系统（hydraulic system）执行元件（actuator）液压缸（cylinder）液压马达（motor）液压回路（circuit）压力控制回路（pressure control）流量（速度）控制回路（speed control）方向控制回路（direction alvalve control）安全回路（security control）定位回路（position control）同步回路（synchronisecircuit）顺序动作回路（sequeuntcircuit）液压泵（pump）阀（valve）压力控制阀（pressure valve）、流量控制阀（flow valve）方向控制阀（direction alvalve）液压辅件（accessory）普通阀（common valve）插装阀（cartridge valve）叠加阀（superimposed valve四、管接头Bite type fittings 卡套式管接头Tube to tube fittings 接管接头union 直通接管接头union elbow 直角管接头union tee 三通管接头union cross 四通管接头Mal stud fittings 端直通管接头Bulkhead fittings 长直通管接头Weld fittings 焊接式管接头Female connector fittings 接头螺母Reducers extenders 变径管接头Banjo fittings 铰接式管接头Adjustable fittings/swivel nut 旋转接头五、伺服阀及伺服系统性能参数Dynamic response 动态频响DDV-direct drive valve 直动式伺服阀NFPA-National Fluid Power Association 美国流体控制学会Phase lag 相位滞后Nozzle flapper valve 喷嘴挡板阀Servo-jet pilot valve 射流管阀Dither 颤振电流Coil impedance 线圈阻抗Flow saturation 流量饱和Linearity 线形度Symmetry 对称性Throttle valve 节流阀Double throttle check valve 双单向节流阀Rotary knob 旋钮Rectifier plate 节流板Servo valve 伺服阀Proportional valve 比例阀Position feedback 位置反馈Progressive flow 渐增流量De-energizing of solenoid 电磁铁释放二、介质类Phosphate ester (HFD-R) 磷酸甘油酯Water-glycol (HFC) 水-乙二醇Emulsion 乳化液Inhibitor缓蚀剂Synthetic lubricating oil 合成油三、液压安装工程Contamination 污染Grout 灌浆Failure 失效Jog 点动Creep爬行Abrasion 摩擦Retract（活塞杆）伸出Extension （活塞杆）缩回Malfunction 误动作Pickling 酸洗Flushing 冲洗Dipping process 槽式酸洗Re-circulation 循环Passivity 钝化Nitric acid 柠檬酸Argon 氩气Butt welding 对接焊Socket welding 套管焊Inert gas welding 惰性气体焊空气处理单元air conditioner unit压力控制回路pressure control circuit安全回路safety circuit差动回路differential circuit调速回路flow control circuit进口节流回路meter-incircuit出口节流回路meter-outcircuit同步回路synchronizing circuit开式回路open circuit闭式回路closed circuit管路布置pipe-work管卡clamper联轴器drive shaft coupling操作台control console控制屏control panel避震喉compensator粘度viscosity运动粘度kinematicviscosity密度density含水量water content闪点flash point防锈性rust protection抗腐蚀性anti-corrosive quality便携式颗粒检测仪portable particle counterSolenoid valve 电磁阀Check valve 单向阀Cartridge valve 插装阀Sandwich plate valve 叠加阀Pilot valve 先导阀Pilot operated check valve 液控单向阀Sub-plate mount 板式安装Manifold block 集成块Pressure relief valve 压力溢流阀Flow valve 流量阀冷却器cooler加热器heater温度控制器thermostat消声器silencer双筒过滤器duplex filter过滤器压降filter pressure drop有效过滤面积effective filtration area 公称过滤精度nominal filtration rating压溃压力collapse pressure填料密封packing seal机械密封mechanical seal径向密封radial seal旋转密封rotary seal活塞密封piston seal活塞杆密封rod seal防尘圈密封wiper seal；scraper组合垫圈bonded washer复合密封件composite seal弹性密封件elastomer seal丁腈橡胶nitrilebutadiene rubber；NBR聚四氟乙烯polytetrafluoroethene；PTFE优先控制overridecontrol压力表pressure gauge压力传感器electrical pressure transducer压差计differential pressure instrument液位计liquid level measuring instrument流量计flow meter压力开关pressure switch脉冲发生器pulse generator液压泵站power station遮盖lap零遮盖zero lap正遮盖over lap负遮盖under lap开口opening零偏null bias零漂null drift阀压降valve pressure drop分辨率resolution频率响应frequency response幅值比amplitude ratio相位移phase lag传递函数transfer function管路flow line硬管rigid tube软管flexible hose工作管路working line回油管路return line补液管路replenishing line控制管路pilot line泄油管路drain line放气管路bleed line接头fitting；connection焊接式接头welded fitting扩口式接头flared fitting快换接头quick release coupling 法兰接头flange connection弯头elbow异径接头reducer fitting流道flow pass油口port闭式油箱sealed reservoir油箱容量reservoir fluid capacity 气囊式蓄能器bladder accumulator 空气污染air contamination固体颗粒污染solid contamination 液体污染liquid contamination空气过滤器air filter油雾气lubricator热交换器heat exchanger分流阀flow divider valve集流阀flow-combining valve截止阀shut-off valve球阀global(ball) valve针阀needle valve闸阀gate valve膜片阀diaphragm valve蝶阀butterfly valve噪声等级noise level 放大器amplifier模拟放大器analogue amplifier数字放大器digital amplifier传感器sensor阈值threshold伺服阀servo-valve四通阀four-way valve喷嘴挡板nozzle flapper液压放大器hydraulic amplifier颤振dither阀极性valve polarity流量增益flow gain对称度symmetry流量极限flow limit零位内泄漏null(quiescent) leakage重复性repeat ability复现性reproducibility漂移drift波动ripple线性度linearity线性区linear region液压锁紧hydraulic clock液压卡紧sticking变量泵variable displacement pump泵的控制control of pump齿轮泵gear pump叶片泵vane pump柱塞泵piston pump轴向柱塞泵axial piston pump法兰安装flange mounting底座安装foot mounting液压马达hydraulic motor刚度stiffness中位neutral position零位zero position自由位free position缸cylinder有杆端rod end无杆端rear end外伸行程extend stroke内缩行程retract stroke缓冲cushioning工作行程working stroke负载压力induced pressure输出力force实际输出力actual force单作用缸single-acting cylinder双作用缸double-acting cylinder差动缸differential cylinder伸缩缸telescopic cylinder阀valve底板sub-plate油路块manifold block板式阀sub-plate valve叠加阀sandwich valve插装阀cartridge valve滑阀slide valve锥阀poppet valve阀芯valve element阀芯位置valve element position单向阀check valve液控单向阀pilot-controlled check valve梭阀shuttle valve压力控制阀pressure relief valve溢流阀pressure relief valve顺序阀sequence valve减压阀pressure reducing valve平衡阀counterbalance valve卸荷阀unloading valve直动式directly operated type先导式pilot-operated type机械控制式mechanically controlled type手动式manually operated type液控式hydraulic controlled type流量控制阀flow control valve固定节流阀fixed restrictive valve可调节流阀adjustable restrictive valve单向节流阀one-way restrictive valve 调速阀speed regulator valve。
液压常用英语
许用工况 acceptable conditions
连续工况 continuous working conditions
实际工况 actual conditions
效率 efficiency
旋转方向 direction of rotation
充油压力 charge pressure
开启压力 cracking pressure
峰值压力 peak pressure
运行压力 operating pressure
耐压试验压力 proof pressure
冲击压力 surge pressure
静压力 static pressure
系统压力 system pressure
外泄漏 external leakage
层流 laminar flow
紊流 turbulent flow
气穴 cavitation
流量 flow rate
排量 displacement
额定流量 rated flow
供给流量 supply flow
流量系数 flower factor
线性度 linearity
线性区 linear region
液压锁紧 hydraulic lock
液压卡紧 sticking
变量泵 variable displacement pump
泵的控制 control of pump
齿轮泵 gear pump
叶片泵 vane pump
柱塞泵 piston pump
脉冲发生器 pulse generator
航空词汇知多少——液压系统
航空词汇知多少——液压系统
hydraulics
[英][haɪˈdrɒlɪks][美][haɪˈdrɔːlɪks]
[名]1.水力学
2.液压装置，液压系统
词汇解读
“hydraulics”的词根hydr来源于希腊神话中的九头蛇怪物海德拉（hydra），表示水。
所以hydraulics指与水有关系的知识集合，水力学。
到了现代，hydraulics变成了液压系统的专有名词。
液压系统可通过改变压强来增大作用力。
因为功率密度大、快速性好、刚度大，所以液压系统广泛应用于航空领域，被称为“飞行器的血管和肌肉”。
液压系统可分为两类：液压传动系统和液压控制系统。
机载液压
系统多为传递动力和运动之用，如操控舵机驱动、起落架收放等。
为保证飞行安全，飞机液压系统往往由几套相互独立的液压源系统组成。
作动力来自液压作动筒。
A380则将液压能与电能有效结合，采用了“2套液压系统和2套电系统”的配置。
电力作动技术的最大优势是取消了复杂的液压管路，减轻了系统重量。
但是需要增加的电缆和作动器，可能抵消这一优势。
未来很长一段时间内，传统机载液压系统和新型多电系统将并行发展。
DOC-机械专业毕业设计外文翻译--什么是液压-液压系统
DOC-机械专业毕业设计外文翻译--什么是液压-液压系统What is Hydraulic?A complete hydraulic system consists of five parts, namely, power components, the implementation of components, control components, no parts 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 valves can be divided into the village of force control valve, 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 dividedinto the hydraulic valve control switch valve, control valve and set thevalue of the ratio control valve. Auxiliary components, including fuel tanks, oil filters, tubing and pipe joints, seals, pressure gauge, oil level, such as oildollars. 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.Hydraulic principleIt 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 oil-filled "hydraulic machine." Each of the two liquida 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, pistontop 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 = PxS2Cross-sectional area is a small multiple of the piston cross-sectional area. From the type known to add in a small piston of asmaller force, the piston will be in great force, for which thehydraulic machine used to suppress plywood, oil, extract heavy objects, such as forging steel.History of the development of hydraulicAnd 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 theworld's first hydraulic press. Media work in 1905 will be replaced byoil-water and further improved.World War I (1914-1918) after 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 Constantine (G • Constantimsco) fluctuations of the ener gy carried out by passing theoretical and practical research; in 1910 on the hydraulic transmission (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 thanEurope and the United States and other countries for nearly 20 years later. Before and after in1955, 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 workers. Plastic processing industry, machinery, pressure machinery, machine tools, etc.; operating machinery engineering machinery, construction machinery, agricultural machinery, automobiles, etc.; iron and steel industry metallurgical machinery, lifting equipment, such as roller adjustment device; civil waterprojects 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, etc.; ship deck crane (winch), the bow doors, bulkhead valves, such as the sternthruster ; 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 devices.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。
机械外文翻译文献翻译液压系统1
外文原文：Theory of fluid propertiesWe will concentrate mainly on three fluid properties in this chapter:• The density which leads to mass and hence to hydraulic inertia effects.• The viscosity which leads to the hydraulic friction effects.• The compressi bility and thus the bulk modulus which leads to the hydraulic system stiffness. Notice that the compressibility effect can be modified by air release, cavitation phenomena and by expansion of a pipe, hose or chamber containing the hydraulic fluid.1 Density and compressibility coefficientThe density is the mass of a substance per unit volume:Density has dimensions of [M/L3] and is expressed in kilograms per cubic meter [kg/m3]. As mentioned previously the density is a function of the pressure and the temperature:This function can be approximated by the first three terms of a Taylor series:This can also be expressed as:WithAndThis equation is the linearized state equation for a liquid. Using the definition of thedensity, the two coefficients α and B can also be expressed as:B is known as the isothermal bulk modulus or for simplicity the bulk modulus and α is known as the cubical expansion coefficient. Since fluid density varies with the applied pressure, this implies that a given mass of fluid submitted to a pressure change changes its volume. This phenomenon leads to the definition of the compressibility coefficient β:where β is expressed in units Pa 1 (or m2/N). Considering the relation for a closed hydraulic circuit the mass is constant, and hence:it follows thatUsing the definition of the compressibility coefficient β we obtain:More usually we use the bulk modulus B also known as the volumetric elasticity modulus:The relation between ρ and B implies mass conservation. This relation must be RIGOROUSLY RESPECTED in the calculations. In the modeling and simulation context of fluid energy systems, disregarding the relation between ρ and B leads to abnormal evolutions of pressure in the closed circuit submitted to compression and expansion cycles. This phenomenon is strongly accentuated if aeration occurs in the circuit (when dissolved air in the fluid reappears in the form of bubbles). We shall approach this point by examining the phenomena of aeration and cavitation. The aircan also have adverse consequences on a fluid compressibility. In liquid air can be present in two forms: entrapped and dissolved.Entrapped airWhen the return pipe is not submersed in the tank the liquid jet can entrain some air bubbles in the tank. Another phenomenon that affects the quantity of air in liquid is the leakage.Figure 1: Liquid leakageFigure 2: Air is entrainedThis air stays in the liquid as cavities and can modify the fluid compressibility. In this context we talk about effective bulk modulus. Figure 3 shows the bulk modulus of a diesel fuel at 40 °C with 0, 0.01, 0.1, 1, 10% air. The plot is obtained using the system shown. The model of the diesel fuel properties is based on accurate ex-perimental measurements and are designed for use with injection system which are very fast acting. For this reason air is assumed to be entrained rather than dissolved.Figure 3Dissolved airAir can also be dissolved in a liquid. A certain amount of air molecule can be part of the liquid. In this case the dissolved air does not significantly change the fluid properties.2 Air release and cavitationAir can be dissolved or entrained in liquids and it is possible for air to change from one of these two forms to the other depending on the conditions to which the fluid is subjected.Suppose the fluid is in equilibrium with a certain percentage of dissolved gas (usually air: nitrogen and oxygen). Lowering the pressure above a critical value called the saturation pressure induces aeration. This is the process where the dissolved gas forms air bubbles in the liquid until all the dissolved gases or air are free.The exact point where all the dissolved gas has come out of solution is difficult to pin-point because it depends on the chemical composition and behavior of the gas. This is a non-symmetrical dynamic process: the growing process does not have the same dynamics as when air bubbles disappear. In consequence the total amount of bubbles created when the pressure drops may or may not be redissolved in the liquid when it rises again.If the pressure is dropped further and above another critical value called the vapor pres s ure, the fluid itself starts to vaporize. It corresponds to a liquid phase change. At some point only fluid vapor and gas exist. In liquid systems the term cavitation usually refers to the formation and collapse of cavities in the liquid even if cavities contain air or liquid vapor.To summarize with a sketch what we have introduced see above:Figure 4: Air release and cavitationThe development of a cavity is now recognized as being associated with a nucleation center such as microscopic gas particles, wear or wall asperities. When the liquid is subjected to a tensile stress, cavities do not form as a result of liquid rupture but are caused by the rapid growth of these nuclei.To understand this, think of beer (or champagne if you prefer) in a bottle, when it is closed you see no air bubbles and the liquid does not look fizzy. The pressure in the bottle is above the saturation pressure of the gas in the liquid. When you open the bottle suddenly bubbles appear and so the dissolved gas (molecules of gas held in the liquid) starts to appear as gas.In fact the liquid is gas saturated and the atmospheric pressure is less than the saturation pressure of the liquid. This phenomenon is clearly not cavitation but air release (aeration). Considering nuclei effects, bubbles form only at particular places in your glass: around the glass (due to small asperities) and round any particles present in the liquid. Theoretically, if your liquid was perfectly pure and the wall of the system perfectly regular, air release or cavitation would occur with great difficulty! The key point about cavitation is that it is a phase change: the liquid changes to vapor.A comparison can be made between cavitation and boiling. If we look at the phasediagram below:Figure 5: Cavitation and boilingBoiling is a phase change at constant pressure and variable temperature and cavitation is a phase change at constant temperature and variable pressure.In any system air release starts first and if the pressure decreases further, cavitation may occur. This means that, sometimes, people talk about cavitation when the real phenomenon is air release. Both phenomena can lead to destruction of the material or component.In both cases it is entrained gas that causes the troubles. When cavities encounter high pressure in the downstream circuit, these bubbles or cavities can be unstable and can collapse implosively. The pressure developed at collapse can be large enough to cause severe mechanical damage in the containing vessel. It is well-known that hydraulic pumps and pipework can be badly damaged by cavitaton and air release.In all classical hydraulic systems air release and cavitation must be avoided to prevent material destruction but sometimes it is required like for injection systems to prepare the spray formation.3 ViscosityViscosity is a measure of the resistance of the fluid to flow. This characteristic has both positive and negative effects on fluid power systems. A low viscosity leads to oil leaks in the dead zone formed between the mechanical parts in movement, and a high viscosity will lead to loss of pressure in hydraulic ducts.Viscosity is a characteristic of liquids and gases and is manifested in motion throughinternal damping. Viscosity results from an exchange of momentum by molecular diffusion between two layers of fluid with different velocities. In this sense, the viscosity is a fluid property and not a flow property.Figure 6: ViscosityFigure 6 shows the relation between shearing constraint and difference of flow velocity between two layers .The definition of viscosity was first given by Newton. Between two layers of distance dy, the exerted force between these two layers is given by:where U(y) is the velocity depending on the radial position y and dU/dy the velocity gradient. This proportionality expresses the notion of Newtonian fluid and allows the introduction of μ defined as the dynamic viscosity or the absolute viscosity.The dimension of μ is [ML1-T 1-] and the SI unit is kg/m/s or Pa s. The older unit is the Poise, P, which is 0.1 kg/m/s. However, this is very small and hence the milli Poise, mP, is the common unit which is 10-4 kg/m/s.The dynamic viscosity is the constant of proportionality between a stress and the intensity of shearing between two neighboring layers:However the absolute viscosity is not very often used in fundamental equations. For example the dynamics of the elementary volume between the two layers is expressedas:and thus using the shear stress calculation:In other formulas (e.g. Navier Stokes) the ratio between the absolute viscosity and the density occurs so often that a new parameter called the kinematic viscosity ν is introduced .of dimension [L2T 1-] and so the SI unit is the m2/s. The older unit of kinematic viscosity is the Stoke, St, which is 104-m2/s. However, even this is a very small unit and hence the centistoke cSt is the common unit with 1 cSt = 106-m2/s. This parameter is easily measured with viscometers.Note that the viscosity varies significantly with the fluid temperature.Figure 7: Viscosity against temperatureNormally in absence of air release and cavitation the variation with pressure is not great unless the pressure is very extreme.Figure 8: Variation with pressureViscosity influence on the flowAnother important aspect of the viscosity is its influence on the flow conditions of the fluid. We can distinguish two types of flow conditions:• Laminar flow for which the flow lines are parallel and shearing forces create a pressure drop.• Turbulent flow for which the fluid particles have a disordered, random movement leading to a loss of pressure.These two conditions can be distinguished using the Reynolds number which is defined as follows:WithU: average fluid velocityd: diameter of the duct (hydraulic diameter for others geometries)ρ: densityμ: dynamic viscosityν: kinematic viscosityThe transition between laminar to turbulent flow occurs at the critical Reynolds number. This is not well defined, there exists always a transition region. In a hydraulic line, the critical Reynolds number is generally between 1500 to 2000. For uneven geometries (thin-walled orifices), the critical Reynolds number can be lower than 100. For non-circular cross sections, the hydraulic diameter can be used to determine the Reynolds number. Hydraulic diameter is defined as follows:We now give one example:• Circular orifice of diameter:Flow through orificesOrifices (also called restrictions) can be fixed or variable and occur in huge numbers in fluid systems. Not surprisingly in Engineering courses a mathematical description is presented. This is usually based on Bernoulli’s equation and leads to the formwhere Cq is the flow coefficient. This is variously described as typically 0.7 or varying with orifice geometry and Reynolds number.The second alternative is obviously more correct. If we do take a constant value, we are forced to have the gradient of Q against infinity at the origin! This cannot be and if you try to implement it is a numerical disaster! Clearly the flow is laminar for sufficiently small pressure drops which means that Cq is certainly not constant. One solution is to perform detailed e xperiments and compute Cq against Reynold’s number. In the context of the orifice (not necessarily circular) the Reynold’s number iswhere U is a mean velocity and dh the hydraulic diameter. If we take U=Q/A, we end up with the form Cq =f(Q) and ultimately withIt is possible to work with an implicit relationship like this but we would prefer an explicit formula.This is provided by introducing another dimensionless number known as the flow number and denoted by λ. This is defined asFrom a modelin g point of view λ contains quantities we know. Using λ we haveand provided we have,we have an explicit relationship which is easy to evaluate. There are no more problems to obtain measurements forthan forand so the flow number form has many advantages.References ：[1] McCloy D, Discharge Characteristics of Servo Valve Orifices, 1968 Fluid International Conference.[2] R.C. Binder, “Fluid Mechanics”. 3rd Edition, 3rd Printing. Prentice-Hall, Inc., Englewood Cliffs,NJ. 1956.译文：液压油理论我们将在本章主要讨论液压油的三个特性：•密度（使油液具有质量和液感效应）；•粘性（使油液具有液阻效应）；•可压缩性和体积弹性模量（使油液具有容性效应），值得提醒的是容性效应会受油液中析出的空气、气穴现象和装有油液的的管道、软管或油腔的影响。
液压系统外文文献翻译中英文
外文文献翻译(含：英文原文及中文译文)英文原文Hydraulic systemW Arnold1 IntroductionThe hydraulic station is called a hydraulic pump station and is an independent hydraulic device. It is step by step to supply oil. And control the direction of hydraulic oil flow, pressure and flow, suitable for the host and hydraulic equipment can be separated on the various hydraulic machinery.After the purchase, the user only needs to connect the hydraulic station and the actuator (hydraulic or oil motor) on the mainframe with different tubings. The hydraulic machine can realize various specified actions and working cycles.The hydraulic station is a combination of manifolds, pump units or valve assemblies, electrical boxes, and tank electrical boxes. Each part function is:The pump unit is equipped with a motor and an oil pump, which is the power source of the hydraulic station and can convert mechanical energy into hydraulic oil pressure energy.V alve combination - its plate valve is mounted on the vertical plate, and the rear plate is connected with the same function as the manifold.Oil manifolds - assembled from hydraulic valves and channel bodies. It regulates hydraulic oil pressure, direction and flow.Box--a semi-closed container for plate welding. It is also equipped with an oil screen, an air filter, etc., which is used for cooling and filtering of oil and oil.Electrical box - divided into two types: one is to set the external lead terminal board; one is equipped with a full set of control appliances.The working principle of the hydraulic station: The motor drives the oil pump to rotate, then the pump sucks oil from the oil tank and supplies oil, converts the mechanical energy into hydraulic pressure energy, and the hydraulic oil passes through the manifold (or valve assembly) to adjust the direction, pressure and flow and then passes through the external tube. The way to the hydraulic cylinder or oil motor in the hydraulic machinery, so as to control the direction of the hydraulic motor, the strength of the speed and speed, to promote all kinds of hydraulic machinery to do work.(1) Development history of hydraulic pressureThe development history of hydraulics (including hydraulic power, the same below), pneumatics, and seals industry in China can be roughly divided into three stages, namely: the starting stage in the early 1950s to the early 60s; and the professional in the 60s and 70s. The growth stage of the production system; the 80-90's is a stage of rapid development. Among them, the hydraulic industry began in the early 1950s with thedevelopment of hydraulic machines such as Grinding Machines, broaching machines, and profiling lathes, which were produced by the machine tool industry. The hydraulic components were produced by the hydraulic workshop in the machine tool factory, and were produced for self use. After entering the 1960s, the application of hydraulic technology was gradually promoted from the machine tool to the agricultural machinery and engineering machinery. The original hydraulic workshop attached to the main engine plant was independent and became a professional manufacturer of hydraulic components. In the late 1960s and early 1970s, with the continuous development of mechanization of production, particularly in the provision of highly efficient and automated equipment for the second automobile manufacturing plant, the hydraulic component manufacturing industry witnessed rapid development. The batch of small and medium-sized enterprises also began to become specialized manufacturers of hydraulic parts. In 1968, the annual output of hydraulic components in China was close to 200,000 pieces. In 1973, in the fields of machine tools, agricultural machinery, construction machinery and other industries, the professional factory for the production of hydraulic parts has grown to over 100, and its annual output exceeds 1 million pieces. Such an independent hydraulic component manufacturing industry has taken shape. At this time, the hydraulic product has evolved from the original imitation Su product intoa combination of imported technology and self-designed products. The pressure has been developed towards medium and high pressures, and electro-hydraulic servo valves and systems have been developed. The application of hydraulics has been further expanded. The pneumatic industry started a few years later than hydraulics, and it was only in 1967 that it began to establish a professional pneumatic components factory. Pneumatic components began to be manufactured and sold as commodities. Its sealing industry including rubber seals, flexible graphite seals, and mechanical seals started from the production of common O-rings, oil seals, and other extruded rubber seals and asbestos seal products in the early 1950s. In the early 1960s, it began to develop and produce flexible products. Graphite seals and mechanical seals and other products. In the 1970s, a batch of batches of professional production plants began to be established one after another in the systems of the former Ministry of Combustion, the Ministry of Agriculture, and the Ministry of Agricultural Machinery, formally forming the industry, which laid the foundation for the development of the seal industry.In the 1980s, under the guidance of the national policy of reform and opening up, with the continuous development of the machinery industry, the contradiction between the basic components lags behind the host computer has become increasingly prominent and caused the attention of all relevant departments. To this end, the former Ministry of Machinesestablished the General Infrastructure Industry Bureau in 1982, and unified the original pneumatic, hydraulic, and seal specialties that were scattered in the industries of machine tools, agricultural machinery, and construction machinery, etc. The management of a piece of office, so that the industry in the planning, investment, the introduction of technology and scientific research and development and other aspects of the basic parts of the bureau's guidance and support. This has entered a period of rapid development, it has introduced more than 60 foreign advanced technology, of which more than 40 hydraulic, pneumatic 7, after digestion and absorption and technological transformation, are now mass production, and has become the industry's leading products . In recent years, the industry has intensified its technological transformation. From 1991 to 1998, the total investment of national, local, and corporate self-raised funds totaled about 2 billion yuan, of which more than 1.6 billion were hydraulic. After continuous technological transformation and technological breakthroughs, the technical level of a group of major enterprises has been further improved, and technological equipment has also been greatly improved, laying a good foundation for forming a high starting point, specialization, and mass production. In recent years, under the guidance of the principle of common development of multiple ownership systems in the country, various small and medium-sized enterprises with different ownership have rapidly emerged and haveshown great vitality. With the further opening up of the country, foreign-funded enterprises have developed rapidly, which plays an important role in raising industry standards and expanding exports. So far China has established joint ventures with famous manufacturers in the United States, Germany, Japan and other countries or directly established piston pumps/motors, planetary speed reducers, hydraulic control valves, steering gears, hydraulic systems, hydrostatic transmissions, and hydraulic components. The company has more than 50 manufacturing enterprises such as castings, pneumatic control valves, cylinders, gas processing triplets, rubber seals, and mechanical seals, and has attracted more than 200 million U.S. dollars in foreign capital.(2) Current statusBasic profileAfter more than 40 years of hard work, China's hydraulics, pneumatics and seals industry has formed a complete industrial system with a certain level of production capacity and technical level. According to the statistics of the third n ational industrial census in 1995, China’s state-owned, privately-owned, cooperative, village-run, individual, and “funded enterprises” have annual sales income of more than 1 million yuan in hydraulic, pneumatic, and seal industrial townships and above. There are a total of more than 1,300 companies, including about 700 hydraulics, and about 300 pneumatic and sealing parts. According to thestatistics of the international industry in 1996, the total output value of the hydraulic industry in China was about 2.448 billion yuan, accounting for the 6th in the world; the total output value of the pneumatic industry was about 419 million yuan, accounting for the world’s10 people.2. Current supply and demand profileWith the introduction of technology, independent development and technological transformation, the technical level of the first batch of high-pressure plunger pumps, vane pumps, gear pumps, general hydraulic valves, oil cylinders, oil-free pneumatic components and various types of seals has become remarkable. Improve, and can be stable mass production, provide guarantees for all types of host to improve product quality. In addition, certain achievements have also been made in the aspects of CAD, pollution control, and proportional servo technology for hydraulic pneumatic components and systems, and have been used for production. So far, the hydraulic, pneumatic and seal products have a total of about 3,000 varieties and more than 23,000 specifications. Among them, there are about 1,200 types of hydraulic pressure, more than 10,000 specifications (including 60 types of hydrodynamic products, 500 specifications); about 1350 types of pneumatic, more than 8,000 specifications; there are also 350 types of rubber seals, more than 5000 The specifications are now basically able to adapt to the general needs ofvarious types of mainframe products. The matching rate for major equipment sets can reach more than 60%, and a small amount of exports has started.In 1998, the domestic production of hydraulic components was 4.8 million pieces, with sales of about 2.8 billion yuan (of which mechanical systems accounted for 70%); output of pneumatic components was 3.6 million pieces, and sales were about 550 million yuan (including mechanical systems accounting for about 60%) The production of seals is about 800 million pieces, and the sales volume is about 1 billion yuan (including about 50% of mechanical systems). According to the statistics of the annual report of the China Hydraulic and Pneumatic Sealing Industry Association in 1998, the production and sales rate of hydraulic products was 97.5% (101% of hydraulic power), 95.9% of air pressure, and 98.7% of seal. This fully reflects the basic convergence of production and sales.Although China's hydraulic, pneumatic and sealing industries have made great progress, there are still many gaps compared with the development needs of the mainframe and the world's advanced level, which are mainly reflected in the variety, performance and reliability of products. . Take hydraulic products as an example, the product varieties are only 1/3 of the foreign country, and the life expectancy is 1/2 of that of foreign countries. In order to meet the needs of key hosts, imported hosts, and majortechnical equipment, China has a large number of imported hydraulic, pneumatic, and sealing products every year. According to customs statistics and relevant data analysis, in 1998, the import volume of hydraulic, pneumatic and seal products was about 200 million U.S. dollars, of which the hydraulic pressure was about 140 million U.S. dollars, the pneumatics were 30 million U.S. dollars, and the seal was about 0.3 billion U.S. dollars. The year is slightly lower. In terms of amount, the current domestic market share of imported products is about 30%. In 1998, the total demand for hydraulic parts in the domestic market was about 6 million pieces, and the total sales volume was 4 billion yuan; the total demand for pneumatic parts was about 5 million pieces, and the total sales volume was over 700 million yuan; the total demand for seals was about 1.1 billion yuan. Pieces, total sales of about 1.3 billion yuan. (3) Future developments1. The main factors affecting development(1) The company's product development capability is not strong, and the level and speed of technology development can not fully meet the current needs for advanced mainframe products, major technical equipment and imported equipment and maintenance;(2) Many companies have lagged behind in manufacturing process, equipment level and management level, and their sense of quality is not strong, resulting in low level of product performance, unstable quality,poor reliability, and insufficiency of service, and lack of user satisfaction. And trusted branded products;(3) The degree of professional specialization in the industry is low, the power is scattered, the duplication of the low level is serious, the product convergence between the region and the enterprise leads to blind competition, and the prices are reduced each other, thus the efficiency of the enterprise is reduced, the funds are lacking, and the turnover is difficult. Insufficient investment in development and technological transformation has severely restricted the overall level of the industry and its competitive strength.(4) When the degree of internationalization of the domestic market is increasing, foreign companies have gradually entered the Chinese market to participate in competition, coupled with the rise of domestic private, cooperative, foreign-funded, and individual enterprises, resulting in increasing impact on state-owned enterprises. .2. Development trendWith the continuous deepening of the socialist market economy, the relationship between supply and demand in the hydraulic, pneumatic and sealed products has undergone major changes. The seller market characterized by “shortage” has basically become a buyer’s market characterized by “structured surplus”. Replaced by. From the perspective of overall capacity, it is already in a trend of oversupply, and in particular,general low-grade hydraulic, pneumatic and seals are generally oversupply; and like high-tech products with high technological content and high value and high value-added products that are urgently needed by the host, Can not meet the needs of the market, can only rely on imports. After China's entry into the WTO, its impact may be greater. Therefore, during the “10th Five-Y ear Plan” period, the growth of the industry’s output value must not only rely on the growth of quantity. Instead, it should focus on the structural contradiction of the industry and intensify efforts to adjust the industrial structure and product structure. It should be based on the improvement of quality. Product technology upgrades in order to adapt to and stimulate market demand, and seek greater development.2. Hydraulic application on power slide(1) Introduction of Power Sliding TableUsing the binding force curve diagram and the state space analysis method to analyze and study the sliding effect and the smoothness of the sliding table of the combined machine tool, the dynamics of the hydraulic drive system of the sliding table—the self-regulating back pressure regulating system are established. mathematical model. Through the digital simulation system of the computer, the causes and main influencing factors of the slide impact and the motion instability are analyzed. What kind of conclusions can be drawn from those, if we canreasonably design the structural dimensions of hydraulic cylinders and self-regulating back pressure regulators ——The symbols used in the text are as follows:s 1 - flow source, that is, the flow rate of the governor valve outlet;S el —— sliding friction of the sliding table;R - the equivalent viscous friction coefficient of the slide;I 1 - quality of slides and cylinders;12 - self-adjusting back pressure valve core quality;C 1, c 2 - liquid volume without cylinder chamber and rod chamber;C 2 - Self-adjusting back pressure valve spring compliance;R 1, R2 - Self-adjusting back pressure valve damping orifice fluid resistance;R 9 - Self-adjusting back pressure valve valve fluid resistance;S e2——initial pre-tightening force of self-adjusting back pressure valve spring;I 4, I5 - Equivalent liquid sense of the pipeline;C 5, C 6 - equivalent liquid capacity of the pipeline;R 5, R7 - Equivalent liquid resistance of the pipeline;V 3, V4 - cylinder rodless cavity and rod cavity volume;P 3, P4—pressure of the rodless cavity and rod cavity of the cylinder;F - the slide bears the load;V - speed of slide motion;In this paper, the power bond diagram and the state space splitting method are used to establish the system's motion mathematical model, and the dynamic characteristics of the slide table can be significantly improved.In the normal operation of the combined machine tool, the magnitude of the speed of the slide, its direction and the load changes it undergoes will affect its performance in varying degrees. Especially in the process of work-in-process, the unsteady movement caused by the advancing of the load on the slide table and the cyclical change of the load will affect the surface quality of the workpiece to be machined. In severe cases, the tool will break. According to the requirements of the Dalian Machine Tool Plant, the author used the binding force curve diagram and the state space analysis method to establish a dynamic mathematical model of a self-adjusting back pressure and speed adjustment system for the new hydraulic drive system of the combined machine tool slide. In order to improve the dynamic characteristics of the sliding table, it is necessary to analyze the causes and main influencing factors of the impetus and movement of the sliding table. However, it must pass the computer's digital simulation and the final results obtained from the research.(2) Dynamic Mathematical ModelThe working principle diagram of the self-adjusting back pressure speedregulation system of the combined machine tool slide hydraulic drive system is shown in the figure. This system is used to complete the work-cycle-stop-rewind. When the sliding table is working, the three-position four-way reversing valve is in the illustrated position. The oil supply pressure of the oil pump will remain approximately constant under the effective action of the overflow valve, and the oil flow passes through the reversing valve and adjusts the speed. The valve enters the rodless chamber of the cylinder to push the slide forward. At the same time, the pressurized oil discharged from the rod chamber of the cylinder will flow back to the tank through the self-regulating back pressure valve and the reversing valve. During this process, there was no change in the operating status of both the one-way valve and the relief valve. The complex and nonlinear system of the hydraulic drive system of the self-adjusting back pressure governor system is a kind of self-adjusting back-pressure governor system. To facilitate the study of its dynamic characteristics, a simple and reasonable dynamic mathematical model that only considers the main influencing factors is established. Especially important [1][2]. From the theoretical analysis and the experimental study, we can see that the system process time is much longer than the process time of the speed control valve. When the effective pressure bearing area of the rodless cavity of the fuel tank is large, the flow rate at the outlet of the speed control valve is instantaneous. The overshoot is reflected in thesmall change in speed of the slide motion [2]. In order to further broaden and deeply study the dynamic characteristics of the system so that the research work can be effectively performed on a miniature computer, this article will further simplify the original model [2], assuming that the speed control valve is output during the entire system pass. When the flow is constant, this is considered to be the source of the flow. The schematic diagram of the dynamic model structure of this system is shown in Fig. 2. It consists of a cylinder, a sliding table, a self-adjusting back pressure valve, and a connecting pipe.The power bond graph is a power flow graph. It is based on the transmission mode of the system energy, based on the actual structure, and uses the centralized parameters to represent the role of the subsystems abstractly as a resistive element R, a perceptual element I, and a capacitive element. Three kinds of role of C. Using this method, the physical concept of modeling is clear, and combined with the state-space analysis method, the linear system can be described and analyzed more accurately. This method is an effective method to study the dynamic characteristics of complex nonlinear systems in the time domain. According to the main characteristics of each component of the self-adjusting back pressure control system and the modeling rules [1], the power bond diagram of the system is obtained. The upper half of each key in the figure represents the power flow. The two variables that makeup the power are the force variables (oil pressure P and force F) and the flow variables (flow q and velocity v). The O node indicates that the system is connected in parallel, and the force variables on each key are equal and the sum of the flow variables is zero; 1 The nodes represent the series connection in the system, the flow variables on each key are equal and the sum of the force variables is Zero. TF denotes a transformer between different energy forms. The TF subscripted letter represents the conversion ratio of the flow variable or the force variable. The short bar on the key indicates the causal relationship between the two variables on the key. The full arrow indicates the control relationship. There are integral or differential relationships between the force and flow variables of the capacitive and perceptual elements in the three types of action elements. Therefore, a complex nonlinear equation of state with nine state variables can be derived from Fig. 3 . In this paper, the research on the dynamic characteristics of the sliding table starts from the two aspects of the slide's hedging and the smoothness of the motion. The fourth-order fixed-length Runge-Kutta is used for digital simulation on the IBM-PC microcomputer.(3) Slide advanceThe swaying phenomenon of the slide table is caused by the sudden disappearance of the load acting on the slide table (such as drilling work conditions). In this process, the table load F, the moving speed V, and thepressure in the two chambers of the cylinder P3 and P4 can be seen from the simulation results in Fig. 4. When the sliding table moves at a uniform speed under the load, the oil pressure in the rodless cavity of the oil cylinder is high, and a large amount of energy is accumulated in the oil. When the load suddenly disappears, the oil pressure of the cavity is rapidly reduced, and the oil is rapidly reduced. When the high-pressure state is transferred to the low-pressure state, a lot of energy is released to the system, resulting in a high-speed forward impact of the slide. However, the front slide of the sliding table causes the pressure in the rod cavity of the oil cylinder to cause the back pressure to rise, thereby consuming part of the energy in the system, which has a certain effect on the kicking of the slide table. We should see that in the studied system, the inlet pressure of the self-adjusting back pressure valve is subject to the comprehensive effect of the two-chamber oil pressure of the oil cylinder. When the load suddenly disappears, the pressure of the self-adjusting back pressure valve rapidly rises and stably exceeds the initial back pressure value. It can be seen from the figure that self-adjusting back pressure in the speed control system when the load disappears, the back pressure of the cylinder rises more than the traditional speed control system, so the oil in the rod cavity of the cylinder absorbs more energy, resulting in the amount of forward momentum of the slide It will be about 20% smaller than traditionalspeed control systems. It can be seen from this that the use of self-adjusting back-gear speed control system as a drive system slider has good characteristics in suppressing the forward punch, in which the self-adjusting back pressure valve plays a very large role.(4) The smoothness of the slideWhen the load acting on the slide changes periodically (such as in the case of milling), the speed of the slide will have to fluctuate. In order to ensure the processing quality requirements, it must reduce its speed fluctuation range as much as possible. From the perspective of the convenience of the discussion of the problem, assume that the load changes according to a sine wave law, and the resulting digital simulation results are shown in Figure 5. From this we can see that this system has the same variation rules and very close numerical values as the conventional speed control system. The reason is that when the change of the load is not large, the pressure in the two chambers of the fuel tank will not have a large change, which will eventually lead to the self-regulating back pressure valve not showing its effect clearly.(5) Improvement measuresThe results of the research show that the dynamic performance of a sliding table with self-regulating back pressure control system as a drive system is better than that of a traditional speed control system. To reduce the amount of kick in the slide, it is necessary to rapidly increase the backpressure of the rod cavity when the load disappears. To increase the smoothness of the sliding table, it is necessary to increase the rigidity of the system. The main measure is to reduce the volume of oil. From the system structure, it is known that the cylinder has a large volume between the rod cavity and the oil discharge pipe, as shown in Fig. 6a. Its existence in terms of delay and attenuation of the self-regulating back pressure valve function, on the other hand, also reduces the rigidity of the system, it will limit the further improvement of the propulsion characteristics and the smoothness of the motion. Thus, improving the dynamic characteristics of the sliding table can be handled by two methods: changing the cylinder volume or changing the size of the self-regulating back pressure valve. Through the simulation calculation of the structural parameters of the system and the comparison of the results, it can be concluded that the ratio of the volume V4 between the rod cavity and the oil discharge pipe to the volume V3 between the rodless cavity and the oil inlet pipe is changed from 5.5 to 5.5. At 1 oclock, as shown in the figure, the diameter of the bottom end of the self-adjusting back pressure valve is increased from the original 10mm to 13mm, and the length of the damper triangle groove is reduced from the original lmm to 0.7mm, which will enable the front of the slide table. The impulse is reduced by 30%, the transition time is obviously shortened, and the smoothness of the slide motion will also be greatly improved.中文译文液压系统W Arnold1. 绪论液压站称液压泵站,是独立的液压装置。
液压制动系统外文文献翻译、汽车车辆外文翻译、中英文翻译
附录AHydraulic Brake SystemsWhen you step on the brake pedal,you expect the vehicle to stop.The brake pedal operates a hydraulic that is used for two reasons.First,fluid under pressure can be carried to all parts of the vehicle by small hoses or metal lines without taking up a lot of room of causing routing problems.Second,the hydraulic fluid offers a great mechanical advantage-little foot pressure is required on the pedal, but a great deal of pressure is generated at the wheels.The brake pedal is linked to a piston in the brake master cylinder containing a small piston and a fluid reservoir.Modern master cylinders are actually two separate cylinders.Such a system is called a dual circuit,because the front cylinder is connected to the front brakes and the rear cylinder to the rear brakes.(Some vehicles are connected diagonally). The two cylinders are actually separated,allowing for emergency stopping power should one part of the system fail.The entire hydraulic system from the master cylinder to the wheels is full of hydraulic brake fluid.When the brake pedal is depressed,the piston in the master cylinder are forced to move,exerting tremendous force on the fluid in the lines.The fluid has nowhere to go,and forces the wheel cylinder pistons(drum brakes) or caliper pistons(disc brakes) to exert pressure on the brake shoes or pads.The friction between the brake shoe and wheel drum or the brake pad and rotor (disc) slows the vehiche and eventually stops it.Also attached to the brake pedal si a switch that lights the brake lights as the pedal is depressed.The lights stay on until the brake pedal is released and returns to its normal position.Each wheel cylinder in a drum brake system contains two pistons,one at either end,which push outward in opposite directions.In disc brake systems,the wheel cylinders are part of the caliper (there can be as many as four or as few as one ).Whether disc or drum type,all pistons use some type of rubber seal to preventleakage around the piston,and a rubber dust boot seals the outer of the wheel cylinders against dirt and moisture.When the brake pedal is released,a spring pushes the master cylinder pistons back to their normal positions.Check valves in the master cylinder piston allow fluid to flow toward the wheel cylinders or calipers as the piston returns.Then as the brake shoe return springs pull the brake shoes back to the released position,excess fluid returns to the master cylinder through compensating ports,which have been uncovered as the pistons move back.Any fluid that has leaked from the system will also be replaced through the compensating ports.All dual circuit brake systems use a switch to activate a light,warning of brake failure.The switch si located in a valve mounted near the master cylinder.A piston in the valve reveives pressure on each end from the front and rear brake circuits.When the pressures are balanced,the piston remains stationary,but when one circuit has a leak,greater pressure during the application of the brakes will force the piston to one side or the other,closing the switch and activating the warning light.The light can also be activated by the ignition switch during engine starting or by the parking brake.Front disc,rear drum brake systems also have a metering valve to prevent the front disc brakes from engaging before the rear brakes have contacted the drums.This ensures that the front brakes will not normally be used alone to stop the vehicle.A proportioning valve is also used to limit pressure to the rear brakes to prevent rear wheel lock-up during hard braking.Brake shoes and pads are constructed in a similar.The pad or shoe is composed of a metal backing plate and a priction lining.The lining is either bonded(glued) to the metal,or riveted.Generally,riveted linings provide superior performance,but good quality bonded linings are perfectly adequate.Friction materials will vary between manufacturers and type of pad and the material compound may be referred to as asbestos,organic,semi-metallic,metallic.The difference between these compounds lies in the types and percentages of friction materials used,material binders and performance modifiers.Generally speaking,organic and non-metallic asbestos compound brakes are quiet,easy on rotors and provide good feel.But this comes at the expense of hightemperature operation,so they may not be your best choice for heavy duty use or mountian driving.In most cases,these linings will wear somewhat faster than metallic compound pads,so you will usually replace them more often.But,when using these pads,rotors tend to last longer.Semi-metallic or metallic compound brake linings will vary in performance based on the metallic contents of the compound.Again,generally speaking,the higher the metallic content,the better the friction material will resist heat.This makes them more appropriate for heavy duty applications,but at the expense of braking performance before the pad reaches operating temperature.The first few applications on a cold morning may not give strong braking.Also,metallics and semi-metallics are more likely to squeal,In most cases,metallic compounds last longer than non-metallic pads,but they tend to cause more wear on the rotors.If you use metallic pads,expect to replace the rotors more often.When deciding what type of brake lining is right for you,keep in mind that today’s modern cars have brake materials which are matched to the expected vehicle’s performance capabilities.Changing the material from OEM specification could adversely addect brake feel or responsiveness.Before changing the brake materials,talk to your deaker or parts supplier to help decide what is most appropriate for your application.Remenber that use applications such as towing,stop and go driving,driving down mountain roads,and racing may require a change to a higher performance material.Some more exotic materials are also used in brake linings,among which are Kevlar and carbon compounds.These materials have the capability of extremely good performance for towing,mountain driving or racing.Wear characteristics can be similar to either applications tend to wear like metallic linings,while many of the streetapplications are more like the non-metallics.附录B液压制动系统当踩下制动踏板，您希望该车辆停下。
液压系统-外文翻译
Hydraulic SystemThere are only three basic methods of transmitting power: electrical, mechanical, and fluid power. Most applications actually use a combination of the three methods to obtain the most efficient overall system. To properly determine which principle method to use, it is important to know the salient features of each type. For example, fluid systems can transmit power more economically over greater distances than can mechanical types. However, fluid systems are restricted to shorter distances than are electrical systems.Hydraulic power transmission system are concerned with the generation, modulation, and control of pressure and flow, and in general such systems include:1.Pumps which convert available power from the prime mover to hydraulic power at the actuator.2.Valves which control the direction of pump-flow, the level of power produced, and the amount of fluid-flow to the actuators. The power level is determined by controlling both the flow and pressure level.3.Actuators which convert hydraulic power to usable mechanical power output at the point required.4.The medium, which is a liquid, provides rigid transmission and control as well as lubrication of components, sealing in valves, and cooling of the system.5.Connectors which link the various system components, provide power conductors for the fluid under pressure, and fluid flow return to tank (reservoir).6.Fluid storage and conditioning equipment which ensure sufficient quality and quantity as well as cooling of the fluid.Hydraulic systems are used in industrial applications such as stamping presses, steel mills , and general manufacturing , agricultural machines , mining industry , aviation , space technology , deep-sea exploration ,transportation , marinetechnology , and offshore gas petroleum exploration . In short, very few people get through a day of their lives without somehow benefiting from the technology of hydraulics.The secret of hydraulic system’s success and widespread use is its versatility and manageability. Fluid power is not hindered by the geometry of the machine as is the case in mechanical systems. Also, power can be transmitted in almost limitless quantities because fluid systems are not so limited by the physical limitations of materials as are the electrical systems. For example, the performance of an electromagnet is limited by the saturation limit of steel. On the other hand, the power limit of fluid systems is limited only by the strength capacity of the material.Industry is going to depend more and more on automation in order to increase productivity. This includes remote and direct control of production operations, manufacturing processes, and materials handling. Fluid power is the muscle of automation because of advantages in the following four major categories.Ease and accuracy of control. By the use of simple levers and push buttons, the operator of a fluid power systems can readily start, stop, speed up or slow down, and position force which provide any desired horsepower with tolerances as precise as one ten-thousandth of an inch.Multiplication of force. A fluid power system (without using cumbersome gears, pulleys, and levers) can multiply forces simply and efficiently from a fraction of an ounce to several hundred tons of output.Constant force or torque. Only fluid power systems are capable of providing constant force or torque regardless of speed changes. This is accomplished whether the work output moves a few inches per hour, several hundred inches per minute, a few revolutions per hour, or thousands of revolutions per minute.Simplicity, safety, economy. In general, fluid power systems use fewer movingparts than comparable mechanical or electrical systems. Thus, they are simpler to maintain and operate. This, in turn, maximizes safety, compactness, and reliability. For example, a new power steering control designed has made all other kinds of power systems obsolete on many off-highway vehicles. The steering unit consists of a manually operated directional control valve and meter in a single body. Because the sterring unit is fully fluid-linked, mechanical linkages, universal joints, bearings, reduction gears, ect . are eliminated. This provides a simple,compact systems.In addition, very little input torque is required to produce the control needed for the toughest applications. This is important where limitations of control space require a small sterring wheel and it becomes necessary to reduce operator fatigue.Additional benefits of fluid power systems include instantly reversible motion, automatic protection against overloads, and infinitely variable speed control. Fluid power systems also have the highest horsepower per weight ratio of any known power source. In spite of all these highly desirable features of fluid power, it is not a panacea for all power transmission problems. Hydraulic systems also have some drawbacks. Hydraulic oils are messy, and leakage is impossible to completely. Also, most hydraulic oils can cause fires if an oil leak occurs in area of hot equipment. There are only three basic methods of transmitting power: electrical, mechanical, and fluid power. Most applications actually use a combination of the three methods to obtain the most efficient overall system. To properly determine which principle method to use, it is important to know the salient features of each type. For example, fluid systems can transmit power more economically over greater distances than can mechanical types. However, fluid systems are restricted to shorter distances than are electrical systems.Hydraulic power transmission system are concerned with the generation, modulation, and control of pressure and flow, and in general such systems include:Pumps which convert available power from the prime mover to hydraulic power at the actuator.Valves which control the direction of pump-flow, the level of power produced, and the amount of fluid-flow to the actuators. The power level is determined by controlling both the flow and pressure level.Actuators which convert hydraulic power to usable mechanical power output at the point required.The medium, which is a liquid, provides rigid transmission and control as well as lubrication of components, sealing in valves, and cooling of the system.Connectors which link the various system components, provide power conductors for the fluid under pressure, and fluid flow return to tank (reservoir).Fluid storage and conditioning equipment which ensure sufficient quality and quantity as well as cooling of the fluid.Hydraulic systems are used in industrial applications such as stamping presses, steel mills , and general manufacturing , agricultural machines , mining industry , aviation , space technology , deep-sea exploration ,transportation , marine technology , and offshore gas petroleum exploration . In short, very few people get through a day of their lives without somehow benefiting from the technology of hydraulics.The secret of hydraulic system’s success and widespread use is its versatility and manageability. Fluid power is not hindered by the geometry of the machine as is the case in mechanical systems. Also, power can be transmitted in almost limitless quantities because fluid systems are not so limited by the physical limitations of materials as are the electrical systems. For example, the performance of an electromagnet is limited by the saturation limit of steel. On the other hand, the power limit of fluid systems is limited only by the strength capacity of the material.Industry is going to depend more and more on automation in order to increase productivity. This includes remote and direct control of production operations, manufacturing processes, and materials handling. Fluid power is the muscle of automation because of advantages in the following four major categories.1. Ease and accuracy of control. By the use of simple levers and push buttons, the operator of a fluid power systems can readily start, stop, speed up or slow down, and position force which provide any desired horsepower with tolerances as precise as one ten-thousandth of an inch.2. Multiplication of force. A fluid power system (without using cumbersome gears, pulleys, and levers) can multiply forces simply and efficiently from a fraction of an ounce to several hundred tons of output.3. Constant force or torque. Only fluid power systems are capable of providing constant force or torque regardless of speed changes. This is accomplished whether the work output moves a few inches per hour, several hundred inches per minute, a few revolutions per hour, or thousands of revolutions per minute.4. Simplicity, safety, economy. In general, fluid power systems use fewer moving parts than comparable mechanical or electrical systems. Thus, they are simpler to maintain and operate. This, in turn, maximizes safety, compactness, and reliability. For example, a new power steering control designed has made all other kinds of power systems obsolete on many off-highway vehicles. The steering unit consists of a manually operated directional control valve and meter in a single body. Because the sterring unit is fully fluid-linked, mechanical linkages, universal joints, bearings, reduction gears, ect . are eliminated. This provides a simple,compact systems.In addition, very little input torque is required to produce the control needed for the toughest applications. This is important where limitations of controlspace require a small sterring wheel and it becomes necessary to reduce operator fatigue.Additional benefits of fluid power systems include instantly reversible motion, automatic protection against overloads, and infinitely variable speed control. Fluid power systems also have the highest horsepower per weight ratio of any known power source. In spite of all these highly desirable features of fluid power, it is not a panacea for all power transmission problems. Hydraulic systems also have some drawbacks. Hydraulic oils are messy, and leakage is impossible to completely. Also, most hydraulic oils can cause fires if an oil leak occurs in area of hot equipment.液压系统仅有以下三种基本方法传递动力：电气，机械和流体。
液压系统构成中英文对照外文翻译文献
(文档含英文原文和中文翻译)中英文资料对照外文翻译The hydraulic system constitutionhydraulic system composition department wind and the function, widely is applying on each kind of mechanical device the hydraulic system, the use has the continual fluid fat liquor now, actuates through the hydraulic pump the hydraulic pump the electric motor or the engine mechanical energy transforms the fat liquor the pressure energy, passes through each kind of control valve, delivers took the actuator in the hydraulic cylinder motor, transforms again while the mechanical power actuates the load. Constitutes such hydraulic system each constituent and the function. The hydraulic system characteristic and the use hydraulic pressure took one transmission technology, has its prominent merit:Can produce the very big power, moreover controls easily; May use the pump to obtain very the high pressure (20-30MPa) hydraulic fluid very easily, sends in this pressure oil the hydraulic cylinder then to produce the very big strength; Can in the very wide scope the limitless speed change; To altogether gives the oil motor or the hydraulic cylinder current capacity with the control valve carries on the stepless adjustment, then at will controls its revolving or the translation speed; Very easy to prevent the overload, the security is big; The size slightly strives in a big way, installs the position to be possible the free choice; Output strength adjustment simple accurate, but long-distance control.Hydraulic system use and service, in order to guarantee the mechanical device non-breakdown the work, must follow the factory the use service request.The hydraulic system is infinitely varied, took the different machinery a constituent, its use matters needing attentionalso differ from naturally.The hydraulic system uses and services the duty including the debugging, the inspection, the service and the repair. How debugs? The debugging is causes the new equipment to put the operation or to cause the original equipment to put the operation a series of activities, including the installment, the oil injection, the flushing, the adjustment, runs gathers. The inspection is examined system active status and function is whether correct, including the observation, the survey and tries to move.The maintenance is refers to the guarantee system the normal function, the few attrition and the replacement wearing parts, including the cleaning up and the replacement components, namely trades the oil, trades ponders the core, trades the seal.The repair is system reply function a series of activities which causes to crash.First must according to the breakdown phenomenon determine expires the spot and verifies the expiration reason, this is the so-called breakdown diagnosis. Then the replacement expiration part, makes the mechanical device to restore the work, this named repair.The expiration part should return the plant to repair.Time use service matters needing attention: When security, use and service hydraulic system, when most important question pays attention to the security, for guarantees the security, has the pressure when the system does not have to loosen the pipe connection, the screw joint or the part.Certainly must put first down the load, causes the pump engine off and releases the accumulator the pressure oil, then opens the thing again, does not have the oil used to work. Although many practical security taboo into general knowledge, but the attention often concentrates in the breakdown phenomenon, but neglects the latent danger.Therefore, in starts to repair the system reason this implementation standardization the engine off procedure, after the repair draws up invests the movement, should implement standardized the again start procedure:Engine off procedure it including following several aspects:1. Puts the low suspension the load or carries on the machinery supports and protections to it.2. Release system3. In release accumulator pressure oil4. Release pressure intensifier both sides pressure oil5. Cut-off electricity control system6.DumpStarts the procedure including following several aspects:1. Elimination expiration root2. If the component failure or the replacement period pollutant enters the system, then according to needs to clean up or the flushing system3. Confirms the part correctly unmistakable4. Confirms the hydraulic pressure connection correctly unmistakable5. Confirms the electrical connection correctly unmistakable6. Adjustable part to secure state7. Fills the oil for the pump and the motor shell8. According to needs to refuel to the system and to deflate9. Relieves the secure interconnection to protect10. Calls the alarm bell and the notice all presents the personnel soon to restart11.Starting systemThe item which this is carries on when service must pay attention, in regarding its sanitary, when service also must pay attention, when service hydraulic system, must do utmost the attention absolutely clean Arab League condition, because the pollutant is the hydraulic system most dangerous enemy.Does not have to carry on the polish and the welding work in the service hydraulic system scene. Loosens in front of the thread must its outside clean first cleanly.With clean returns to protects changes passes over the system the interior to use to open the mouth to seal, guards against the pollutant to enter thesystem.Cleans up when the fuel tank does not permit the use cotton and kapok silk and the rags.Must pass through the filter to the system oil injection.In the tubing, refuels with the flushing is the maintenance clean important link, its matters needing attention are as follows:1. The tubing pipe or the hose damage when must replace immediately.When chooses the pipe, the hose, the screw connector or the flange, must guarantee the pressure rated value (i.e. wall thickness, material quality and so on) satisfy the operation requirements.The hard tube must use the seamless steel pipe.The steel pipe and the metal pipe connection must clean absolutely before the installment, does not have the oil dirt, to scale, the welding, the scrap and so on.May use the steel wire brush, the tube cleaner to clean up or the acid pickling.In front of the acid pickling pipe must carry on degreasing processing, after the acid pickling must clean thoroughly. After cutting in the pipe bank or ridge between fields should the articulation awl hole, remove the burr which possibly has, but cannot ream excessively in order to avoid sells the weak connection.After assembly the pipe does not have again to weld or the gas welding, because is unable to clean up.The hose should the curved several times in order to release any detention the dirty thing.In front of the elbow piece the tubing wants the annealing, prevented when elbow piece the corrugation or changes flat.Wants the accurate elbow piece, enable the pipe then not to arrive after the elastic deformation. The flange must in the fitting surface coordinate smoothly before, and with the length suitable bolt fastening, whether there is the screw connector does install should inspect in the thread the metal burr, in the straight thread does not permit the use seal bandage.If the drive pipe must deposit period of time, should stop up the orifice to prevent the foreign matter enters.But does not have to use the rags or other moves the capital to stop up the orifice, because this only can bring the contamination concern, should use the size appropriate seal cap.2. Refuels the oil drum to want horizontal-type depositing, as far as possible deposits in the room or the awning, opens in front of the oil tung, cleans the barrel to go against and the bung thoroughly, prevented the soil and other outside pollutant enter the fat liquor.Only with the clean vessel, the hose and so on transports the fat liquor from the oil drum to the fuel tank.The recommendation with has at least in the 25um filter feeding pump. Provides 200 goals in the fuel tank oiling tube to ponder the net.The filter is actually specially for the system need oil fluid variety use.Sometimes also discovers the pollutant in the new fat liquor, therefore should for work through the portable purifier the hydraulic system tops up. When portable purifier hose involvement fuel tank, should use cloth attachment cleaning which clean does not shed hair to be clean, prevented the soil and other impurities enter the system.3.Before flushing flushing should take down the precise system part, but installs the pipe nipple in its position or hollow.From the main pipeline which flushes is dismantled the system to ponder the core.The flushing current capacity should for the system anticipated current capacity 2-2.5 times.If possible, use heat flush fluid (85℃).Each time only flushes a leg, from most approaches the wash out pump the return route start, to the downstream advancement, this possibly must additionally build in turn in the system up to the valve, realizes this kind of plan. Cannot use the system pump to take the wash out pump.Generally speaking, the power type pump like centrifugal pump and so on may provide the enough flood peak and the great current capacity, the movement quite is economical, and to flushes the period circulation the pollutant to have the good es the capacity in the flushing system with to use the flushing filter which the current capacity matches, the filtration precision to be as far as possible high, does not have to be lower than the recommendation system filtration precision. If has the possibility, uses the assistance to flush the fuel tank to avoid the pollutant being detained in the system fuel tank.The establishment fat liquor sample plan inspects dustiness, thus determined when finished the flushing procedure.After flushing, takes all measures to prevent when rewiring work part leads the pollutant.4.The replacement part part model must correct unmistakable.When if cannot find the similar model the part to have to use the similar part substitutes, must pay attention to the function, the parameter, the connection size is whether consistent, but also must pay attention installs the position, the ambient temperature, the working voltage and so on.The old seal packing collar must replace, does not permit two uses.The bolt and the screw connector must even screw tight the big stipulation the torque, prevents the part distortion influence work. The adjustable part like delivery valve, the flow valve, the variable displacement pump and so on must establish.5.When accumulator accumulator pressure vessel, Asia locality related safety rule compulsory control.In is loaded with on the accumulator hydraulic system carries on in front of any work, must first download the system pressure.The accumulator shell does not permit the welding and the processing, does not repair when possibly causes the serious accident, therefore must have to repair the accumulator returns delivers the plant to carry on the repair.Hydraulic pump selection: The hydraulic pump is the hydraulic system power supply.Must select can adapt the pressure which the actuator requests to have the return route pump, simultaneously must consider fully the reliability, the life Maintainability one side and so on elect the pump can plant the long-term movement in the system.The hydraulic pump type are extremely many, its characteristic also has the very big difference. Chooses when the hydraulic pump must consider the factor has working pressure, current capacity, rotational speed, quota or variable, variable way, volumetric efficiency, overall effectiveness index, the prime mover type, the noise, the pressure oscillation rate, self-absorption ability and so on, but also must consider and the hydraulic fluid compatibility, the size, the weight, the economy, Maintainability, these factors.The hydraulic pump discharge pressure should be the actuator needs the pressure, the tubing pressure loses, the control valve sum of pressure loss, it does not have to surpass in the sample the rated pressure, when the emphasis security, the reliability.Also should leave leeway the big leeway.In when sample highest working pressure when short-term impact permits pressure.If each circulation plants all has the impact pressure, the pump life can reduce obviously, even the pump can damage.Hydraulic pump life: The hydraulic pump is the hydraulic system power part, its function is transforms the prime mover mechanical energy the liquid the pressure energy, refers to in the hydraulic system the oil pump, it provides the power to the entire hydraulic system.Hydraulic pump structural style common toothed wheel pump, vane pump and ram pump. Affects the hydraulic pump the service life factor to be very many, except outside pump own design, manufacture factor and some with pump use Guanyuan (for example shaft coupling, oil filter and so on) selects, in the test run movement process operation and so on also concerns.1.The air compressorselects the air compressor the basis is the working pressure and the current capacity which the pneumatic system needs.At present, the pneumatic system commonly used working pressure is 0.5~0.8MPa, may select the rated pressure is directly the 0.7~1MPa low-pressure air compressor, the special need fluid may select, high-pressured or the ultrahigh voltage air compressor. When determination air compressor air displacement, should satisfy the biggest gas consumption which each air operated equipment needs (to be supposed to transform into free air gas consumption) the sum.(1) was mad the source refining equipmentgeneral use the air compressor all uses the oil lubrication, the air is compressed in the air compressor, the temperature may elevate 140~170℃, by now were partial the lubricating oil to turn the gas, mixed in the compressed air, in addition in the air water and the dust, formed included mix impurity and so on the water vapor, oil gas, dust compressed air.Ifprovides this kind of compressed air to the air operated equipment use, will be able to have following adverse consequences:Gathers in the compressed air the oil gas to gather in the gas storage fills forms the combustible, even has the detonation danger; Simultaneously the oil vaporizes after the high temperature forms the organic acid, causes the hardware to corrode, affects the equipment the life.(2)The mix impurity deposition in the pipeline and the air operated part, causes to pass flows the area to reduce, circulation drag increment, the overall system work is unstable, when serious, system knock off.(3)In the compressed air water vapor can congeal the waterdrop under certain pressure and the temperature, can cause the pipeline and the assistance part in the cold season because of freezes destroys.(4)In the compressed air dust has the abrasive action to the air operated part movement part, causes it attrition to be serious, affects their life.Thus it can be seen, establishes in the pneumatic system eliminates the water, eliminates the oil, the dust removal and dry and so on was mad the source refining equipment is extremely essential.Second, the air operated assistance partair operated part interior has many relative slippers, somewhat relative slipper depends on the seal packing collar to seal.In order to reduce transports the moving parts relatively the friction force, guaranteed the part movement is normal; In order to reduce the packing material the attrition, prevents divulging; In order to prevent the pipeline and the metal part corrosion, lengthens the part service life, guaranteed the good lubrication is extremely important.The lubrication may not divide into and spurts the mist lubrication for the oil lubrication.Some many air operated application domain does not allow to spurt the mist lubrication.If food and the drugs packing, in the transportation process, the oil granule returns to pollution food and the drugs; The oil granule can affect certain raw material for industry, the chemicals nature; The oil mist can affect the high-level spray coating surface and the electronic component surface quality; The oil mist can affect the measuring instrument true the survey; The oil mist can harm the human body health and so on.Therefore at present uses the mist lubrication to reduce gradually, does not give the oil lubrication already very popularly.Still did not use the rubber material for the oil lubrication to take the glide spot the seal, but sealed has the detention tank special structure, in order to memory lubricant.Other components should use not the easy rusty metal material or the nonmetallic material.For the oil lubrication part also may not to the oil use, once but gives the oil, does not have the midway to stop feed.At the same time, must prevent the condensed water enters in the part, in order to avoid flushes the lubricant.Not only has not saved the lubricating utensils and the lubricating oil for the oil lubrication part, improved the working conditions, moreover reduced the maintenance work load, reduced the cost.Moreover, also improved the lubrication condition.Its lubrication effect with the transit discharge, the pressure height, the tubing condition and so on all has nothing to do with.Also does not exist forgot refuels creates the breakdown the matter.The mist lubrication part has the oil mist and the centralism lubrication part two kinds.In (1) pneumatic system each kind of air valve, the air cylinder, the gas motor and so on, its movable part all needs to lubricate, but take the compressed air all seals the air chamber as the power air operated part, cannot use the general method oil injection, only can mix in by some method the oil in the air current, the belt to the place which needs to lubricate.The oil mist is this kind of kind of special oil injection installment.After it causes the lubrication oilatomization to pour into in the air current, enters the part along with the air which needs to lubricate. Refuels with this method, has the lubrication to be even, to be stable, the oil consumption few and does not need characteristics and so on big oil storage equipment.(2) air strainer is in the pneumatic system important link, is further filters the dust compressed air the impurity.The filter form are very many, the commonly used type includes: The disposable filter and two filter, have been requesting the high special occasion, may use the highly effective filter.99. In the pneumatic actuator system, called generally the filter, the oil mist, the pressure relief valve for air operated three association (or three big-ticket items), are in the pneumatic system the essential auxiliary unit.(3) silencerpneumatic circuit and the hydraulic pressure return route are different, it does not suppose the exhaust pipeline generally, after the compressed air use the direct platoon person atmosphere, because the gas rapidly inflation and forms the turbulent flow phenomenon, will have the intense exhaust noise.The exhaust speed and the power are bigger, the exhaust noise is bigger, may generally big 100~200dB.The noise harms people's physical and moral integrity directly, must eliminate or weaken.For the noise reduction, generally often installs the silencer in the pneumatic system air vent.The air operated functional elementair operated functional element is transforms in the pneumatic system the compressed air pressure energy the mechanical energy the part.It including air cylinder friendly motor.The air cylinder uses in realizing the straight reciprocating motion or swinging, was mad the motor uses in realizing the continual gyroscopic motion.First, The air cylinderair cylinder is in the pneumatic system the most commonly used one kind of functional element, compares with the hydraulic cylinder, it has the structure simply, pollutes, the movement few keen, responded quick, easy to make, easily to service, the cost low status merit, but because the thrust force is small, widely uses in the underloading system.(1) The air cylinder classifiedbasis air cylinder exploitation conditions are different, its structure, the shape, the type are very many, below introduces several kind of classifications.May divide into according to the compressed air function in the piston end surface direction: List function air cylinder and double-acting air cylinder.(2)Different may divide into according to the structure characteristic: Plunger-type air cylinder, plunger air cylinder, film air cylinder, leaf blade type oscillating cylinder, gear strip type oscillating cylinder and so on.(3) May divide into according to the air cylinder function: Ordinary air cylinder and special air cylinder.The ordinary air cylinder refers to the general plunger-type air cylinder, uses in the not special request the situation.The special air cylinder uses in having the special request situation, like was mad - - the fluid damping cylinder, the film air cylinder, flush are mad the air cylinder, the expansion and contraction air cylinder and so on.(4) According to installs the way differently to be possible to divide into: The ear place type, the flange type, sell the shaft type and the flange type and so on.(二)Common air cylinder principle of work and applicationThe ordinary air cylinder principle of work and the use are similar to the hydraulic cylinder, here no longer give unnecessary detail, below only introduces the special air cylinder.1. Is mad - - the fluid damping cylinderbecause the ordinary air cylinder works time, the compressed gas condensibility is big, when the outside work load change is big, the air cylinder appears “crawling” or “self-propelled” the phenomenon, the stability When therefore the equip ment precision is high, the air cylinder work stable request is also high, often uses was mad - - the fluiddamping cylinder is becomes by the air cylinder and the hydraulic cylinder combination, take the compressed air as an energy, by the hydraulic fluid took the control adjustment air cylinder velocity of movement the medium, the use liquid incompressibility control liquid displacement, adjusts the piston the velocity of movement, obtains the piston the steady motion.2. The film air cylinderfilm type air cylinder is replaces the piston by the thin film the air cylinder.It mainly by the cylinder body, the diaphragm, the diaphragm capsule and the connecting rod and so on the major parts is composed.Has the list to affect the type and the double-acting type.液压系统的构成液压系统的组成部风及其作用，如今在各种机械设备上广泛应用着的液压系统,使用具有连续流动性的油液,通过液压泵把驱动液压泵的电动机或发动机的机械能转换成油液的压力能,经过各种控制阀,送到作为执行器的液压缸马达中,再转换乘机械动力去驱动负载.构成这样的液压系统的各个组成部分及其作用.液压系统的特点和用途液压作为一种传动技术,有其突出的优点:能产生很大的动力,而且控制容易；可以用泵很容易地得到很高压力(20-30MPa)的液压油,把此压力油送入液压缸即可产生很大的力；能在很宽范围内无极变速；用控制阀对共给液压马达或液压缸的流量进行无级调整,即可随意控制其旋转或直线运动的速度；很容易防止过载,安全性大；尺寸小出力大,安装位置可自由选择；输出力的调整简单准确,可远程控制.液压系统的使用与维修，为了保证机械设备无故障的工作，必须遵循制造厂的使用维修要求。
hydraulic 翻译
hydraulic 翻译基本解释●hydraulic：液压的，水力的●/haɪˈdrɔːlɪk/●adj. 液压的，水力的具体用法●adj.:o液压的，水力的o同义词：pneumatic, mechanical, fluidic, hydrostatic, aquiferous o反义词：manual, non-mechanical, dry, non-hydraulic, non-fluidic o例句：●The hydraulic system in the car allows for smooth braking andsteering, which enhances the overall driving experiencesignificantly.●汽车中的液压系统使刹车和转向更加顺畅，从而显著提升了整体驾驶体验。
●Engineers are working on a new hydraulic lift that can carryheavier loads with greater efficiency and safety.●工程师们正在研发一种新的液压升降机，可以更高效和安全地承载更重的负载。
●Hydraulic power is often used in construction equipment tomove heavy materials with precision and control.●液压动力常用于建筑设备中，以精确和控制地移动重物。
●The hydraulic press is capable of exerting immense pressure,making it ideal for shaping and molding metal parts.●液压机能够施加巨大的压力，非常适合用于成型和模压金属零件。
●In the field of renewable energy, hydraulic turbines play acrucial role in converting water flow into electricity.●在可再生能源领域，水力涡轮机在将水流转化为电力方面起着至关重要的作用。
液压专业中英文对照
液压专业词汇流体传动hydraulic power液压技术hydraulics液力技术hydrodynamics气液技术hydropneumatics运行工况operating conditions额定工况rated conditions极限工况limited conditions瞬态工况instantaneous conditions稳态工况steady-state conditions许用工况acceptable conditions连续工况continuous working conditions 实际工况actual conditions效率efficiency旋转方向direction of rotation公称压力nominal pressure工作压力working pressure进口压力inlet pressure出口压力outlet pressure压降pressure drop；differential pressure 背压back pressure启动压力breakout pressure充油压力charge pressure开启压力cracking pressure峰值压力peak pressure运行压力operating pressure耐压试验压力proof pressure冲击压力surge pressure静压力static pressure系统压力system pressure控制压力pilot pressure充气压力pre—charge pressure吸入压力suction pressure调压偏差override pressure额定压力rated pressure耗气量air consumption泄漏leakage内泄漏internal leakage外泄漏external leakage层流laminar flow紊流turbulent flow气穴cavitation流量flow rate排量displacement额定流量rated flow供给流量supply flow流量系数flower factor滞环hysteresis图形符号graphical symbol液压气动元件图形符号symbols for hydraulic and pneumatic components 流体逻辑元件图形符号symbols for fluid logic devices逻辑功能图形符号symbols for logic functions回路图circuit diagram压力－时间图pressure time diagram功能图function diagram循环circle自动循环automatic cycle工作循环working cycle循环速度cycling speed工步phase停止工步dwell phase工作工步working phase快进工步rapid advance phase快退工步rapid return phase频率响应frequency response重复性repeat ability复现性reproducibility漂移drift波动ripple线性度linearity线性区linear region液压锁紧hydraulic lock液压卡紧sticking变量泵variable displacement pump泵的控制control of pump齿轮泵gear pump叶片泵vane pump柱塞泵piston pump轴向柱塞泵axial piston pump法兰安装flange mounting底座安装foot mounting液压马达hydraulic motor刚度stiffness中位neutral position零位zero position自由位free position缸cylinder有杆端rod end无杆端rear end外伸行程extend stroke内缩行程retract stroke缓冲cushioning工作行程working stroke负载压力induced pressure输出力force实际输出力actual force单作用缸single—acting cylinder双作用缸double—acting cylinder差动缸differential cylinder伸缩缸telescopic cylinder阀valve底板sub—plate油路块manifold block板式阀sub—plate valve叠加阀sandwich valve插装阀cartridge valve滑阀slide valve锥阀poppet valve阀芯valve element阀芯位置valve element position单向阀check valve液控单向阀pilot—controlled check valve 梭阀shuttle valve压力控制阀pressure relief valve溢流阀pressure relief valve顺序阀sequence valve减压阀pressure reducing valve平衡阀counterbalance valve卸荷阀unloading valve直动式directly operated type先导式pilot—operated type机械控制式mechanically controlled type 手动式manually operated type液控式hydraulic controlled type流量控制阀flow control valve固定节流阀fixed restrictive valve可调节流阀adjustable restrictive valve 单向节流阀one-way restrictive valve 调速阀speed regulator valve分流阀flow divider valve集流阀flow—combining valve截止阀shut-off valve球阀global（ball) valve针阀needle valve闸阀gate valve膜片阀diaphragm valve蝶阀butterfly valve噪声等级noise level放大器amplifier模拟放大器analogue amplifier数字放大器digital amplifier传感器sensor阈值threshold伺服阀servo—valve四通阀four-way valve喷嘴挡板nozzle flapper液压放大器hydraulic amplifier颤振dither阀极性valve polarity流量增益flow gain对称度symmetry流量极限flow limit零位内泄漏null(quiescent）leakage 遮盖lap零遮盖zero lap正遮盖over lap负遮盖under lap开口opening零偏null bias零漂null drift阀压降valve pressure drop分辨率resolution频率响应frequency response幅值比amplitude ratio相位移phase lag传递函数transfer function管路flow line硬管rigid tube软管flexible hose工作管路working line回油管路return line补液管路replenishing line控制管路pilot line泄油管路drain line放气管路bleed line接头fitting；connection焊接式接头welded fitting扩口式接头flared fitting快换接头quick release coupling法兰接头flange connection弯头elbow异径接头reducer fitting流道flow pass油口port闭式油箱sealed reservoir油箱容量reservoir fluid capacity气囊式蓄能器bladder accumulator空气污染air contamination固体颗粒污染solid contamination液体污染liquid contamination空气过滤器air filter油雾气lubricator热交换器heat exchanger冷却器cooler加热器heater温度控制器thermostat消声器silencer双筒过滤器duplex filter过滤器压降filter pressure drop有效过滤面积effective filtration area 公称过滤精度nominal filtration rating 压溃压力collapse pressure填料密封packing seal机械密封mechanical seal径向密封radial seal旋转密封rotary seal活塞密封piston seal活塞杆密封rod seal防尘圈密封wiper seal；scraper组合垫圈bonded washer复合密封件composite seal弹性密封件elastomer seal丁腈橡胶nitrile butadiene rubber；NBR聚四氟乙烯polytetrafluoroethene;PTFE优先控制override control压力表pressure gauge压力传感器electrical pressure transducer 压差计differential pressure instrument液位计liquid level measuring instrument流量计flow meter压力开关pressure switch脉冲发生器pulse generator液压泵站power station空气处理单元air conditioner unit压力控制回路pressure control circuit安全回路safety circuit差动回路differential circuit调速回路flow control circuit进口节流回路meter-in circuit出口节流回路meter-out circuit同步回路synchronizing circuit开式回路open circuit闭式回路closed circuit管路布置pipe-work管卡clamper联轴器drive shaft coupling操作台control console控制屏control panel避震喉compensator粘度viscosity运动粘度kinematic viscosity密度density含水量water content闪点flash point防锈性rust protection抗腐蚀性anti-corrosive quality便携式颗粒检测仪portable particle counter Solenoid valve 电磁阀Check valve 单向阀Cartridge valve 插装阀Sandwich plate valve 叠加阀Pilot valve 先导阀Pilot operated check valve 液控单向阀Sub—plate mount 板式安装Manifold block 集成块Pressure relief valve 压力溢流阀Flow valve 流量阀Throttle valve 节流阀Double throttle check valve 双单向节流阀Rotary knob 旋钮Rectifier plate 节流板Servo valve 伺服阀Proportional valve 比例阀Position feedback 位置反馈Progressive flow 渐增流量De—energizing of solenoid 电磁铁释放二、介质类Phosphate ester （HFD—R) 磷酸甘油酯Water—glycol （HFC）水-乙二醇Emulsion 乳化液Inhibitor缓蚀剂Synthetic lubricating oil 合成油三、液压安装工程Contamination 污染Grout 灌浆Failure 失效Jog 点动Creep爬行Abrasion 摩擦Retract（活塞杆）伸出Extension （活塞杆）缩回Malfunction 误动作Pickling 酸洗Flushing 冲洗Dipping process 槽式酸洗Re-circulation 循环Passivity 钝化Nitric acid 柠檬酸Argon 氩气Butt welding 对接焊Socket welding 套管焊Inert gas welding 惰性气体焊四、管接头Bite type fittings 卡套式管接头Tube to tube fittings 接管接头union 直通接管接头union elbow 直角管接头union tee 三通管接头union cross 四通管接头Mal stud fittings 端直通管接头Bulkhead fittings 长直通管接头Weld fittings 焊接式管接头Female connector fittings 接头螺母Reducers extenders 变径管接头Banjo fittings 铰接式管接头Adjustable fittings/swivel nut 旋转接头五、伺服阀及伺服系统性能参数Dynamic response 动态频响DDV-direct drive valve 直动式伺服阀NFPA—National Fluid Power Association 美国流体控制学会Phase lag 相位滞后Nozzle flapper valve 喷嘴挡板阀Servo-jet pilot valve 射流管阀Dither 颤振电流Coil impedance 线圈阻抗Flow saturation 流量饱和Linearity 线形度Symmetry 对称性Hysterics 滞环Threshold 灵敏度Lap 滞后Pressure gain 压力增益Null 零位Null bias 零偏Null shift 零飘Frequency response 频率响应Slope 曲线斜坡液压系统（hydraulic system）执行元件（actuator)液压缸（cylinder）液压马达（motor）液压回路（circuit）压力控制回路（pressure control)流量（速度）控制回路（speed control)方向控制回路（directional valve control）安全回路（security control)定位回路（position control）同步回路（synchronise circuit）顺序动作回路（sequeunt circuit）液压泵（pump）阀（valve）压力控制阀（pressure valve）、流量控制阀（flow valve）方向控制阀（directional valve）液压辅件（accessory）普通阀（common valve）插装阀（cartridge valve）叠加阀（superimposed valve液压专业词汇流体传动hydraulic power液压技术hydraulics液力技术hydrodynamics气液技术hydropneumatics运行工况operating conditions额定工况rated conditions极限工况limited conditions瞬态工况instantaneous conditions稳态工况steady—state conditions许用工况acceptable conditions连续工况continuous working conditions实际工况actual conditions效率efficiency旋转方向direction of rotation公称压力nominal pressure工作压力working pressure进口压力inlet pressure出口压力outlet pressure压降pressure drop；differential pressure背压back pressure启动压力breakout pressure充油压力charge pressure开启压力cracking pressure峰值压力peak pressure运行压力operating pressure耐压试验压力proof pressure冲击压力surge pressure静压力static pressure系统压力system pressure控制压力pilot pressure充气压力pre-charge pressure吸入压力suction pressure调压偏差override pressure额定压力rated pressure耗气量air consumption泄漏leakage内泄漏internal leakage外泄漏external leakage层流laminar flow紊流turbulent flow气穴cavitation流量flow rate排量displacement额定流量rated flow供给流量supply flow流量系数flower factor滞环hysteresis图形符号graphical symbol液压气动元件图形符号symbols for hydraulic and pneumatic components 流体逻辑元件图形符号symbols for fluid logic devices逻辑功能图形符号symbols for logic functions回路图circuit diagram压力－时间图pressure time diagram功能图function diagram循环circle自动循环automatic cycle工作循环working cycle循环速度cycling speed工步phase停止工步dwell phase工作工步working phase快进工步rapid advance phase快退工步rapid return phase频率响应frequency response重复性repeat ability复现性reproducibility漂移drift波动ripple线性度linearity线性区linear region液压锁紧hydraulic lock液压卡紧sticking变量泵variable displacement pump泵的控制control of pump齿轮泵gear pump叶片泵vane pump柱塞泵piston pump轴向柱塞泵axial piston pump法兰安装flange mounting底座安装foot mounting液压马达hydraulic motor刚度stiffness中位neutral position零位zero position自由位free position缸cylinder有杆端rod end无杆端rear end外伸行程extend stroke内缩行程retract stroke缓冲cushioning工作行程working stroke负载压力induced pressure输出力force实际输出力actual force单作用缸single—acting cylinder双作用缸double-acting cylinder差动缸differential cylinder伸缩缸telescopic cylinder阀valve底板sub—plate油路块manifold block板式阀sub—plate valve叠加阀sandwich valve插装阀cartridge valve滑阀slide valve锥阀poppet valve阀芯valve element阀芯位置valve element position单向阀check valve液控单向阀pilot—controlled check valve 梭阀shuttle valve压力控制阀pressure relief valve溢流阀pressure relief valve顺序阀sequence valve减压阀pressure reducing valve平衡阀counterbalance valve卸荷阀unloading valve直动式directly operated type先导式pilot-operated type机械控制式mechanically controlled type 手动式manually operated type液控式hydraulic controlled type流量控制阀flow control valve固定节流阀fixed restrictive valve可调节流阀adjustable restrictive valve 单向节流阀one—way restrictive valve 调速阀speed regulator valve分流阀flow divider valve集流阀flow—combining valve截止阀shut—off valve球阀global(ball）valve针阀needle valve闸阀gate valve膜片阀diaphragm valve蝶阀butterfly valve噪声等级noise level放大器amplifier模拟放大器analogue amplifier数字放大器digital amplifier传感器sensor阈值threshold伺服阀servo—valve四通阀four—way valve喷嘴挡板nozzle flapper液压放大器hydraulic amplifier颤振dither阀极性valve polarity流量增益flow gain对称度symmetry流量极限flow limit零位内泄漏null(quiescent）leakage遮盖lap零遮盖zero lap正遮盖over lap负遮盖under lap开口opening零偏null bias零漂null drift阀压降valve pressure drop分辨率resolution频率响应frequency response幅值比amplitude ratio相位移phase lag传递函数transfer function管路flow line硬管rigid tube软管flexible hose工作管路working line回油管路return line补液管路replenishing line控制管路pilot line泄油管路drain line放气管路bleed line接头fitting；connection焊接式接头welded fitting扩口式接头flared fitting快换接头quick release coupling 法兰接头flange connection弯头elbow异径接头reducer fitting流道flow pass油口port闭式油箱sealed reservoir油箱容量reservoir fluid capacity 气囊式蓄能器bladder accumulator 空气污染air contamination固体颗粒污染solid contamination 液体污染liquid contamination空气过滤器air filter油雾气lubricator热交换器heat exchanger冷却器cooler加热器heater温度控制器thermostat消声器silencer双筒过滤器duplex filter过滤器压降filter pressure drop有效过滤面积effective filtration area公称过滤精度nominal filtration rating压溃压力collapse pressure填料密封packing seal机械密封mechanical seal径向密封radial seal旋转密封rotary seal活塞密封piston seal活塞杆密封rod seal防尘圈密封wiper seal;scraper组合垫圈bonded washer复合密封件composite seal弹性密封件elastomer seal丁腈橡胶nitrile butadiene rubber；NBR 聚四氟乙烯polytetrafluoroethene；PTFE 优先控制override control压力表pressure gauge压力传感器electrical pressure transducer 压差计differential pressure instrument液位计liquid level measuring instrument 流量计flow meter压力开关pressure switch脉冲发生器pulse generator液压泵站power station空气处理单元air conditioner unit压力控制回路pressure control circuit安全回路safety circuit差动回路differential circuit调速回路flow control circuit进口节流回路meter—in circuit出口节流回路meter—out circuit同步回路synchronizing circuit开式回路open circuit闭式回路closed circuit管路布置pipe—work管卡clamper联轴器drive shaft coupling操作台control console控制屏control panel避震喉compensator粘度viscosity运动粘度kinematic viscosity密度density含水量water content闪点flash point防锈性rust protection抗腐蚀性anti-corrosive quality便携式颗粒检测仪portable particle counter Solenoid valve 电磁阀Check valve 单向阀Cartridge valve 插装阀Sandwich plate valve 叠加阀Pilot valve 先导阀Pilot operated check valve 液控单向阀Sub-plate mount 板式安装Manifold block 集成块Pressure relief valve 压力溢流阀Flow valve 流量阀Throttle valve 节流阀Double throttle check valve 双单向节流阀Rotary knob 旋钮Rectifier plate 节流板Servo valve 伺服阀Proportional valve 比例阀Position feedback 位置反馈Progressive flow 渐增流量De—energizing of solenoid 电磁铁释放二、介质类Phosphate ester (HFD—R）磷酸甘油酯Water—glycol (HFC）水—乙二醇Emulsion 乳化液Inhibitor缓蚀剂Synthetic lubricating oil 合成油三、液压安装工程Contamination 污染Grout 灌浆Failure 失效Jog 点动Creep爬行Abrasion 摩擦Retract（活塞杆）伸出Extension (活塞杆）缩回Malfunction 误动作Pickling 酸洗Flushing 冲洗Dipping process 槽式酸洗Re-circulation 循环Passivity 钝化Nitric acid 柠檬酸Argon 氩气Butt welding 对接焊Socket welding 套管焊Inert gas welding 惰性气体焊四、管接头Bite type fittings 卡套式管接头Tube to tube fittings 接管接头union 直通接管接头union elbow 直角管接头union tee 三通管接头union cross 四通管接头Mal stud fittings 端直通管接头Bulkhead fittings 长直通管接头Weld fittings 焊接式管接头Female connector fittings 接头螺母Reducers extenders 变径管接头Banjo fittings 铰接式管接头Adjustable fittings/swivel nut 旋转接头五、伺服阀及伺服系统性能参数Dynamic response 动态频响DDV-direct drive valve 直动式伺服阀NFPA—National Fluid Power Association 美国流体控制学会Phase lag 相位滞后Nozzle flapper valve 喷嘴挡板阀Servo—jet pilot valve 射流管阀Dither 颤振电流Coil impedance 线圈阻抗Flow saturation 流量饱和Linearity 线形度Symmetry 对称性Hysterics 滞环Threshold 灵敏度Lap 滞后Pressure gain 压力增益Null 零位Null bias 零偏Null shift 零飘Frequency response 频率响应Slope 曲线斜坡液压系统(hydraulic system)执行元件（actuator）液压缸（cylinder）液压马达（motor）液压回路（circuit）压力控制回路（pressure control）流量(速度）控制回路（speed control)方向控制回路（directional valve control）安全回路（security control）定位回路（position control)同步回路（synchronise circuit)顺序动作回路(sequeunt circuit）液压泵（pump）阀（valve)压力控制阀（pressure valve)、流量控制阀(flow valve）方向控制阀（directional valve)液压辅件（accessory）普通阀（common valve）插装阀（cartridge valve）叠加阀（superimposed valve。
外文翻译--Komatsu先进的液压系统
毕业设计(论文)外文资料翻译学院(系)：机械工程学院专业：机械工程及自动化姓名：学号：外文出处：Manufacturing Engineering (用外文写)and Technology-Machining附件： 1.外文资料翻译译文；2.外文原文。
指导教师评语：此翻译文章简单介绍Komatsu先进的液压系统，并详细介绍了先进的液压传动装置，并对计算机控制的自动变速系统进行了详细的描述，翻译用词比较准确，文笔也较为通顺，为在以后工作中接触英文资料打下了基础。
签名：年月日附件1：外文资料翻译译文Komatsu先进的液压系统操作舒适，生产能力大人性化设计的驾驶室——既宽敞又实用。
宽大的有色玻璃窗给操作员极大的视线。
带扶手五挡调节座椅，短行程手摇杆，上位开启前窗和带杠杆的驾驶用的脚踏板，所有这些都起到有助于操作员最大限度地提高产量的作用。
操作噪声低——这完全是因为有先进的OLSS液压系统以及封闭式发动机室和具有橡胶支垫的发动机。
所有这一切都有助于降低驾驶室的噪声。
手控操作杆——使得施工设备的操作轻而易举。
安装在扶手上的手控操作杆最大行程仅为65mm(2.6in),KOMATSU比例压力控制操作系统能减少准确控制施工设备所需的操作强度。
回转制动装置——即使推土机停泊在坡路上也能自动防止液压漂移。
操作员不再需要在施工设备作业的过程中用手握住制动装置。
此外，回转控制装备还配置有封闭式滑阀，以便顺利的启动和停止。
行驶/驾驶控制装置——脚踏板控制装置配有可拆卸的控制杆。
两者可根据实际运用和操作员的偏爱加以选择使用。
支垫机构——在臂缸悬臂首端、铲斗缸和底部卸料缸中，能消减液压缸伸展和收缩引起的震动，从而增加操作的舒适性，延长部件的寿命。
燃耗最低两种模式选择系统，挖掘效率高——模式选择开关可选定泵驱动功率的两种模式：S（标准模式）或（轻负荷模式）。
当需要大功率挖掘时，选择标准模式；当挖掘机用来运送轻材料或平地时，选择轻负载模式。
液压方面的英语词汇
液压方面的英语单词目录按字母排序 (1)按分类排序 (10)其他总结的词汇 (13)按字母排序Aability 性能；能力load-carrying ability 承载能力absorber 吸收器；吸收剂；过滤器；减震器accessories 辅件，附件，配件hydraulic accessories 液压辅件accumulate 储存；蓄能；累积accumulator 蓄能器；蓄电池；累加器accuracy 准确性；精度action 作用；动作；作用力；行程actuated 操纵，控制directly actuated 直接操纵的，直接控制的pilot actuated 先导控制的，液控的actuator 执行元件；液压缸；马达adapter 接头；衬套；压环；连接件pipe adapter 管接头admission 供给，供油，供气alignment 找正，定心，对中amplifier 放大器differential pressure amplifier 压差放大器flow amplifier 流量放大器assembly 组合，组件，机组axis 轴Bback-flow 回流back-up 支撑hydrostatic back-up 静压支撑barrel 桶，缸体base 底座；支座bearing 支承；轴承；方位radial ball bearing 径向球轴承rolling bearing 滚动轴承sliding bearing 滑动轴承thrust bearing 止推轴承bed 台pump test bed 泵试验台behavior 性能；工况bend 弯头；弯管blade 叶片flat blade 平面叶片forward inclined blade 前倾叶片guide blade 导叶radial blade 径向叶片bleed 排气air bleed 排气阀bleeder 排气孔block 块；封闭；块体cartridge valve block 插装阀块体choke block 节流板directional control block 多路阀，方向控制阀组panel block 阀板组body 体；缸筒；阀体，壳体pump body 泵体tank body 箱体valve body 阀体bolt 螺栓；插销；螺杆boss 轮毂bottom 底；底部cylinder bottom 缸底；缸后盖bracket 支架pump bracket 泵架bubble-tight 气密的buffer 缓冲器，阻尼器bush(ing) 套，导向套；衬套Ccap 帽,盖,罩,塞cylinder end cap 缸端盖cylinder head cap 缸前盖capacity 容量;功率;排量;流量effective capacity 有效排量,实际排量geometric capacity 几何排量,理论排量casing 套,壳,罩gear casing 齿轮箱，变速箱pump casing 泵体cavitation 气蚀cavity 腔centering 中心调整，定心chamber 腔，室；容积；油腔；气腔chamfer 槽；倒角changement 换向机构characteristic 特性曲线；特征线charger 加载装置charging 充液；充压choke 节流；节流口chord 弦circlip 弹性挡圈circuit 回路clearance 间隙clog 阻塞；堵塞cock 龙头collar 圈；法兰盘cushion collar 缓冲套locating collar 定位凸缘套loose collar 轴肩挡圈thrust collar 止推环connection 连接；连接管路；接头consumption 消耗量cylinder 缸；液压缸Ddebugging 排除故障；调试deflation 排气delivery 流量differential 差动的；微分的displacement 压出；排出；排量；位移dowel 定位销drained 泄油的duty 负载，功率；工况Eeffect 作用;效应cavitate effect 气蚀效应choking effect 节流作用elbow 弯头electro-hydraulic 电液的entrap 困油escape 泄漏,逸出,排出etching 蚀刻;腐蚀gas etching 气蚀exhaust 排泄;回油;Ffailure 故障;事故;损坏,失效fastener 紧固件fatigue 疲劳feedback 反馈filler 加油口,注油口;填料;垫片filter 滤油器flow 流;液流;流程;流束;流量;流动nominal flow 公称流量rated flow 额定流量stationary flow 定常流,定常流动streamline flow 层流turbulent flow 紊流volume flow 体积流量flowline 管路;流线flow-regulator 流量调节阀fluctuation 脉动fluid 流体,液体;射流hydraulic operating fluid 液压油incompressible fluid 不可压缩流体frame 座,架Ggain 增益flow gain 流量增益feedback gain 反馈增益gap 间隙,缝隙gear 齿轮,装置,机构governing 调节,控制Hhead 缸头,头部;盖;水头;扬程cylinder head 缸头static head 静压头theoretic head 理论能头total head 总能头water head 水头hole 孔,洞air hole 气孔blind hole 盲孔bolt hole 螺栓孔bose 胶管,软管housing 壳体;槽hub 毂;衬套hydrostatics 液压技术,液体静力学Iidling 空转impact 冲击,撞击impeller 叶轮closed impeller 闭式叶轮open impeller 开式叶轮pump impeller 泵叶轮incidence 入射;入射角blade incidence 叶片安装角incompressible 不可压缩的inlet 进口;吸入intensifier 增压器intensity 强度Jjack (柱塞)缸;千斤顶joint 接头;关节cross joint 十字接头flange joint 法兰式接头screwed joint 螺纹接头journal 轴颈jump 跳动;振动pressure jump 压力突变Kkeyway 键槽Llag 滞后;延迟servovalve phase lag 伺服阀相位滞后laminar 层流的latch 插销;锁紧装置;锁定leak 漏;漏油;渗漏处;漏出物line 管路;线路liner 衬套;导向套;内层胶liquid 液体(的);液力的load 负载;载荷location 位置;定位;安装lock 锁;闭锁;液压卡紧loop 环;环路;回路;循环control loop 控制回路,调节回路main loop 主回路servo loop 伺服回路loss 损失bend loss 弯头损失blade loss 叶片损失line loss 管路损失local pressure loss 局部压力损失partial loss 局部损失lubricate 润滑lug 耳轴lifting lug 吊环Mmandrel 心轴;芯棒manometer 压力机,压力表meter 米;仪表;计量;节制;控制(流量);流量计meter-in 进口节流meter-out 出口节流motion 动作alternative motion 往复运动lost motion 空转synchronized motion 同步运动motor 发动机,液压马达axial piston motor 轴向柱塞马达bent axis piston motor 斜轴式轴向柱塞马达cam plate type axial piston motor 斜盘式轴向柱塞马达constant displacement motor 定量马达radial motor 径向马达sliding vane motor 叶片马达swing motor 摆动马达Nnominal 额定的,公称的notch 凹槽relief notch 卸荷槽null 零位Ooff-load 卸荷oil 油oiler 注油器olive 球面卡套grooved olive 迷宫密封环operation 运行;操作;运算orifice 小孔;节流孔O-ring O型密封圈output 输出;排量;流量overload 过载Ppack 包,捆;组合件,部件,单元power pack 液压泵站package包,捆;组件,单元hydraulic package 液压泵站power package 泵站packing 密封;密封装置;填料密封pad 衬垫;底座asbestos pad 石棉垫valve pad 阀垫parameter 参数part 部分;零件;部件partition 隔板passage 流道;通道;通过pedestal 支座,底座motor pedestal 电动机座phenomenon 现象stick-alip phenomenon 爬行现象trapping phenomenon 困油现象piece 零件,部件pilot(-actuate,-operate) 先导控制;液控piloted 先导控制的pin 销;插头alignment pin 定位销cottar pin 开口销locking pin 锁紧销piston pin 活塞销straight pin 圆柱销pipe 管子,管道(尤指铸铁管和钢管) piston 活塞;柱塞;阀芯double acting piston 双作用活塞double rod piston 双杆活塞hollow piston 空心活塞single-rod piston 单杆活塞pit 坑;槽pitch 节距pitting 凹痕;锈斑;点蚀plug 堵塞;阻塞;堵头air release plug 排气塞plug-in 插入式的,组合式的poppet 提动阀芯,座阀芯,锥阀芯,碟形阀芯pore 孔;孔隙port 油口;连接口position 位置;状态;定位center valve position 阀的中间位置neutral position 中位;零位three position 三位two position 二位pressure 压力,压强;气压pulsation 脉动,波动pump 泵bent axis axial piston pump 斜轴式轴向柱塞泵booster pump 辅助泵,充液泵cam plate type axial piston pump 斜盘式轴向柱塞泵centrifugal pump 离心泵constant delivery pump 定量泵cycloid rotor pump 摆线转子泵double action vane pump 双作用叶片泵gear pump 齿轮泵multi-stage pump 多级泵single action vane pump 单作用叶片泵vane pump 叶片泵variable capacity pump 变量泵Rrabbet 球铰rack 齿条;机架racing 空转radian 弧度radius 半径range 范围,量程rated 额定的regulation 调节,调整regulator 调节器,调压阀differential pressure regulator 定差减压阀proportional pressure regulator 定比减压阀relay 继电器relief 释压;溢流;卸荷reset 复位restriction 节流;阻尼,节流口,阻尼孔restrictor 节流阀;节流口;阻尼孔reversal 反转,倒转revolution 旋转;转数rider 导向套ring 环,圈anti-extrusion ring 密封挡圈,挡圈back support ring 后支承环back-up ring 挡圈bearing ring 导向套dust ring 防尘圈retainer ring 卡环seal ring 密封圈;密封环rod 杆;活塞杆Sscrew 螺杆,螺钉,丝杆,螺旋seal 密封;封口;密封件;密封装置seat 阀座,座seizure 卡死,咬住,擦伤selector 换向阀servo 伺服;伺服机构,伺服系统servomotor 伺服马达servopump 伺服泵servovalve 伺服阀set 组件;定位;集合shaft 轴pump shaft 泵轴sleeve 套;套管;卡套;阀套slot 缝,隙,槽spring 弹簧stroke 行程symbol 符号functional symbol 职能符号Ttank 箱,缸;油箱;容器tee 三通接头,三通throttle 节流;节流阀trapping 困油travel 位移;行程tube 管子(尤指有色金属和无缝钢管) tubeline 管路Uunion 中间接头;直通接头Vvalve 阀back pressure valve 背压阀bypass valve 旁通阀;溢流阀change valve 换向阀check valve 单向阀direct operated solenoid valve 电磁阀flow regulating valve 调速阀four port valve 四通阀four position valve 四位阀hand operated valve 手动阀hydraulic operated check valve 液控单向阀overflow valve 溢流阀overload relief valve 安全阀;过载溢流阀piloted valve 先导式阀vane 叶片diffusion vane 导叶vent 放气;排气孔volume 容积,体积displacement volume 排量Wwasher 垫圈;衬垫wiper 防尘圈Zzone 地带;区(域)dead zone 死区high pressure zone 高压区low pressure zone 低压区按分类排序一、阀类出口节流回路meter-out circuit同步回路synchronizing circuit开式回路open circuit闭式回路closed circuit管路布置pipe-work管卡clamper联轴器drive shaft coupling操作台control console控制屏control panel避震喉compensator粘度viscosity运动粘度kinematic viscosity密度density含水量water content闪点flash point防锈性rust protection抗腐蚀性anti-corrosive quality便携式颗粒检测仪portable particle counter 电磁阀Solenoid valve单向阀Check valve插装阀Cartridge valve叠加阀Sandwich plate valve先导阀Pilot valve液控单向阀Pilot operated check valve板式安装Sub-plate mount集成块Manifold block压力溢流阀Pressure relief valve流量阀Flow valve节流阀Throttle valve双单向节流阀Double throttle check valve 旋钮Rotary knob节流板Rectifier plate伺服阀Servo valve比例阀Proportional valve位置反馈Position feedback渐增流量Progressive flow电磁铁释放De-energizing of solenoid二、介质类磷酸甘油酯Phosphate ester (HFD-R)水-乙二醇Water-glycol (HFC)乳化液Emulsion缓蚀剂Inhibitor合成油Synthetic lubricating oil三、液压安装工程污染Contamination灌浆Grout失效Failure点动Jog爬行Creep摩擦Abrasion（活塞杆）伸出Retract（活塞杆）缩回Extension误动作Malfunction酸洗Pickling冲洗Flushing槽式酸洗Dipping process循环Re-circulation钝化Passivity柠檬酸Nitric acid氩气Argon对接焊Butt welding套管焊Socket welding惰性气体焊Inert gas welding四、管接头Bite type fittings 卡套式管接头Tube to tube fittings接管接头union 直通接管接头union elbow 直角管接头union tee 三通管接头union cross 四通管接头Mal stud fittings 端直通管接头Bulkhead fittings 长直通管接头Weld fittings 焊接式管接头Female connector fittings 接头螺母Reducers extenders 变径管接头Banjo fittings 铰接式管接头Adjustable fittings/swivel nut 旋转接头五、伺服阀及伺服系统性能参数Dynamic response 动态频响DDV-direct drive valve 直动式伺服阀NFPA-National Fluid Power Association 美国流体控制学会Phase lag 相位滞后Nozzle flapper valve 喷嘴挡板阀Servo-jet pilot valve 射流管阀Dither 颤振电流Coil impedance 线圈阻抗Flow saturation 流量饱和Linearity 线形度Symmetry 对称性Hysterics 滞环Threshold 灵敏度Lap 滞后Pressure gain 压力增益Null 零位Null bias 零偏Null shift 零飘Frequency response 频率响应Slope 曲线斜坡液压系统（hydraulic system）执行元件（actuator）液压缸（cylinder）液压马达（motor）液压回路（circuit）压力控制回路（pressure control）流量（速度）控制回路（speed control）方向控制回路（directional valve control）安全回路（security control）定位回路（position control）同步回路（synchronise circuit）顺序动作回路（sequeunt circuit）液压泵（pump）阀（valve）压力控制阀（pressure valve）流量控制阀（flow valve）方向控制阀（directional valve）液压辅件（accessory）普通阀（common valve）其他总结的词汇流体传动hydraulic power液压技术hydraulics液力技术hydrodynamics气液技术hydropneumatics运行工况operating conditions额定工况rated conditions极限工况limited conditions瞬态工况instantaneous conditions稳态工况steady-state conditions许用工况acceptable conditions连续工况continuous working conditions 实际工况actual conditions效率efficiency旋转方向direction of rotation公称压力nominal pressure工作压力working pressure进口压力inlet pressure出口压力outlet pressure压降pressure drop；differential pressure背压back pressure启动压力breakout pressure充油压力charge pressure开启压力cracking pressure峰值压力peak pressure运行压力operating pressure耐压试验压力proof pressure冲击压力surge pressure静压力static pressure系统压力system pressure控制压力pilot pressure充气压力pre-charge pressure吸入压力suction pressure调压偏差override pressure额定压力rated pressure耗气量air consumption泄漏leakage内泄漏internal leakage外泄漏external leakage层流laminar flow紊流turbulent flow气穴cavitation流量flow rate排量displacement额定流量rated flow供给流量supply flow流量系数flower factor滞环hysteresis图形符号graphical symbol液压气动元件图形符号symbols for hydraulic and pneumatic components 流体逻辑元件图形符号symbols for fluid logic devices逻辑功能图形符号symbols for logic functions回路图circuit diagram压力－时间图pressure time diagram功能图function diagram循环circle自动循环automatic cycle工作循环working cycle循环速度cycling speed工步phase停止工步dwell phase工作工步working phase快进工步rapid advance phase快退工步rapid return phase频率响应frequency response重复性repeat ability复现性reproducibility漂移drift波动ripple线性度linearity线性区linear region液压锁紧hydraulic lock液压卡紧sticking变量泵variable displacement pump 泵的控制control of pump齿轮泵gear pump叶片泵vane pump柱塞泵piston pump轴向柱塞泵axial piston pump法兰安装flange mounting底座安装foot mounting液压马达hydraulic motor刚度stiffness中位neutral position零位zero position自由位free position缸cylinder有杆端rod end无杆端rear end外伸行程extend stroke内缩行程retract stroke缓冲cushioning工作行程working stroke负载压力induced pressure输出力force实际输出力actual force单作用缸single-acting cylinder双作用缸double-acting cylinder差动缸differential cylinder伸缩缸telescopic cylinder阀valve底板sub-plate油路块manifold block板式阀sub-plate valve叠加阀sandwich valve插装阀cartridge valve滑阀slide valve锥阀poppet valve阀芯valve element阀芯位置valve element position单向阀check valve液控单向阀pilot-controlled check valve 梭阀shuttle valve压力控制阀pressure relief valve溢流阀pressure relief valve顺序阀sequence valve减压阀pressure reducing平衡阀counterbalance valve卸荷阀unloading valve直动式directly operated type先导式pilot-operated type机械控制式mechanically controlled type 手动式manually operated type液控式hydraulic controlled type流量控制阀flow control valve固定节流阀fixed restrictive valve可调节流阀adjustable restrictive valve 单向节流阀one-way restrictive valve调速阀speed regulator valve分流阀flow divider valve集流阀flow-combining valve截止阀shut-off valve球阀global(ball) valve针阀needle valve闸阀gate valve膜片阀diaphragm valve蝶阀butterfly valve噪声等级noise level放大器amplifier模拟放大器analogue amplifier数字放大器digital amplifier传感器sensor阈值threshold伺服阀servo-valve四通阀four-way valve喷嘴挡板nozzle flapper液压放大器hydraulic amplifier颤振dither阀极性valve polarity流量增益flow gain对称度symmetry流量极限flow limit零位内泄漏null(quiescent) leakage 遮盖lap零遮盖zero lap正遮盖over lap负遮盖under lap开口opening零偏null bias零漂null drift阀压降valve pressure drop分辨率resolution频率响应frequency response幅值比amplitude ratio相位移phase lag传递函数transfer function管路flow line硬管rigid tube软管flexible hose工作管路working line回油管路return line补液管路replenishing line控制管路pilot line泄油管路drain line放气管路bleed line接头fitting；connection焊接式接头welded fitting扩口式接头flared fitting快换接头quick release coupling法兰接头flange connection弯头elbow异径接头reducer fitting流道flow pass油口port闭式油箱sealed reservoir油箱容量reservoir fluid capacity气囊式蓄能器bladder accumulator 空气污染air contamination固体颗粒污染solid contamination 液体污染liquid contamination空气过滤器air filter油雾气lubricator热交换器heat exchanger冷却器cooler加热器heater温度控制器thermostat消声器silencer双筒过滤器duplex filter过滤器压降filter pressure drop有效过滤面积effective filtration area公称过滤精度nominal filtration rating压溃压力collapse pressure填料密封packing seal机械密封mechanical seal径向密封radial seal旋转密封rotary seal活塞密封piston seal活塞杆密封rod seal防尘圈密封wiper seal；scraper组合垫圈bonded washer复合密封件composite seal弹性密封件elastomer seal丁腈橡胶nitrile butadiene rubber；NBR 聚四氟乙烯polytetrafluoroethene；PTFE 优先控制override control压力表pressure gauge压力传感器electrical pressure transducer 压差计differential pressure instrument液位计liquid level measuring instrument 流量计flow meter压力开关pressure switch脉冲发生器pulse generator液压泵站power station空气处理单元air conditioner unit压力控制回路pressure control circuit安全回路safety circuit差动回路differential circuit调速回路flow control circuit进口节流回路meter-in circuit。
液压控制系统-液压液外文文献翻译、中英文翻译
CHAPTER 3HYDRAULIC FLUIDSDuring the design of equipment that requires fluid power, many factors are considered in selecting the type of system to be used—hydraulic, pneumatic, or a combination of the two. Some of the factors are required speed and accuracy of operation, surrounding atmospheric conditions, economic conditions, availability of replacement fluid, required pressure level, operating temperature range, contamination possibilities, cost of transmission lines, limitations of the equipment, lubricity, safety to the operators, and expected service life of the equipment.After the type of system has been selected, many of these same factors must be considered in selecting the fluid for the system. This chapter is devoted to hydraulic fluids. Included in it are sections on the properties and characteristics desired of hydraulic fluids; types of hydraulic fluids; hazards and safety precautions for working with, handling, and disposing of hydraulic liquids; types and control of contamination; and sampling.PROPERTIESIf fluidity (the physical property of a substance that enables it to flow) and incompressibility were the only properties required, any liquid not too thick might be used in a hydraulic system. However, a satisfactory liquid for a particular system must possess a number of other properties. The most important properties and some characteristics are discussed in the following paragraphs.VISCOSITYViscosity is one of the most important properties of hydraulic fluids. It is a measure of a fluids resistance to flow. A liquid, such as gasoline, which flows easily, has a low viscosity; and a liquid, such as tar, which flows slowly, has a high viscosity. The viscosity of a liquid is affected by changes in temperature and pressure. As the temperature of a liquid increases, its viscosity decreases. That is, a liquid flows more easily when it is hot than when it is cold. The viscosity of a liquid increases as the pressure on the liquid increases.A satisfactory liquid for a hydraulic system must be thick enough to give a good seal at pumps, motors, valves, and so on. These components depend on close fits for creating and maintaining pressure. Any internal leakage through these clearances results in loss of pressure, instantaneous control, and pump efficiency. Leakage losses are greater with thinner liquids (low viscosity). A liquid that is too thin will also allow rapid wearing of moving parts, or of parts that operate under heavy loads. On the other hand, if the liquid is too thick (viscosity too high), the internal friction of the liquid will cause an increase in the liquids flow resistance through clearances of closely fitted parts, lines, and internal passages. This results in pressuredrops throughout the system, sluggish operation of the equipment, and an increase in power consumption.Measurement of ViscosityViscosity is normally determined by measuring the time required for a fixed volume of a fluid (at a given temperature) to flow through a calibrated orifice or capillary tube. The instruments used to measure the viscosity of a liquid are known as viscometers or viscosimeters.Figure 3-1.Saybolt viscometer.Several types of viscosimeters are in use today. The Say bolt viscometer, shown in figure 3-1, measures the time required, in seconds, for 60 milliliters of the tested fluid at 100°F to pass through a standard orifice. The time measured is used to express the fluids viscosity, in Saybolt universal seconds or Saybolt furol seconds.Figure 3-2.Various styles of glass capillary viscometers.The glass capillary viscometers, shown in figure 3-2, are examples of the second type of viscometer used. These viscometers are used to measure kinematic viscosity. Like the Saybolt viscometer, the glass capillary measures the time in seconds required for the tested fluid to flow through the capillary. This time is multiplied by the temperature constant of the viscometer in use to provide the viscosity, expressed in centistokes.The following formulas may be used to convert centistokes (cSt units) to approximate Say bolt universal seconds (SUS units). For SUS values between 32 and 100: SUS SUS cST 195226.0-⨯= For SUS values greater than 100: SUS SUS cST 195220.0-⨯=Although the viscometers discussed above are used in laboratories, there are other viscometers in the supply system that is available for local use. These viscometers can be used to test the viscosity of hydraulic fluids either prior to their being added to a system or periodically after they have been in an operating system for a while.Additional information on the various types of viscometers and their operation can be found in the Physical Measurements Training Manual, NA V AIR 17-35QAL-2.Viscosity IndexThe viscosity index (V.I.) of oil is a number that indicates the effect of temperature changes on the viscosity of the oil. A low V.I. signifies a relatively large change of viscosity with changes of temperature. In other words, the oil becomes extremely thin at high temperatures and extremely thick at low temperatures. On the other hand, a high V.I. signifies relatively little change in viscosity over a wide temperature range.Ideal oil for most purposes is one that maintains a constant viscosity throughout temperature changes. The importance of the V.I. can be shown easily by considering automotive lubricants. Oil having a high V.I. resists excessive thickening when the engine is cold and, consequently, promotes rapid starting and prompt circulation; it resists excessive thinning when the motor is hot and thus provides full lubrication and prevents excessive oil consumption.Another example of the importance of the V.I. is the need for high V.I. hydraulic oil for military aircraft, since hydraulic control systems may be exposed to temperatures ranging from below –65°F at high altitudes to over 100°F on the ground. For the proper operation of the hydraulic control system, the hydraulic fluid must have a sufficiently high V.I. to perform its functions at the extremes of the expected temperature range.Liquids with a high viscosity have a greater resistance to heat than low viscosity liquids which have been derived from the same source. The average hydraulic liquid has a relatively low viscosity. Fortunately, there is a wide choice of liquids available for use in the viscosity range required of hydraulic liquids.The V.I. of an oil may be determined if its viscosity at any two temperatures is known. Tables, based on a large number of tests, are issued by the American Society for Testing and Materials (ASTM). These tables permit calculation of the V.I. from known viscosities.LUBRICATING POWERIf motion takes place between surfaces in contact, friction tends to oppose the motion. When pressure forces the liquid of a hydraulic system between the surfaces of moving parts, the liquid spreads out into a thin film which enables the parts to move more freely. Different liquids, including oils, vary greatly not only in their lubricating ability but also in film strength. Film strength is the capability of a liquid to resist being wiped or squeezed out from between the surfaces when spread out in an extremely thin layer. A liquid will no longer lubricate if the film breaks down, since the motion of part against part wipes the metal clean of liquid.Lubricating power varies with temperature changes; therefore, the climatic and working conditions must enter into the determination of the lubricating qualities of a liquid. Unlike viscosity, which is a physical property, the lubricating power and film strength of a liquid isdirectly related to its chemical nature. Lubricating qualities and film strength can be improved by the addition of certain chemical agents.CHEMICAL STABILITYChemical stability is another property which is exceedingly important in the selection of a hydraulic liquid. It is defined as the liquids ability to resist oxidation and deterioration for long periods. All liquids tend to undergo unfavorable changes under severe operating conditions. This is the case, for example, when a system operates for a considerable period of time at high temperatures.Excessive temperatures, especially extremely high temperatures, have a great effect on the life of a liquid. The temperature of the liquid in the reservoir of an operating hydraulic system does not always indicate the operating conditions throughout the system. Localized hot spots occur on bearings, gear teeth, or at other points where the liquid under pressure is forced through small orifices. Continuous passage of the liquid through these points may produce local temperatures high enough to carbonize the liquid or turn it into sludge, yet the liquid in the reservoir may not indicate an excessively high temperature.Liquids may break down if exposed to air, water, salt, or other impurities, especially if they are in constant motion or subjected to heat. Some metals, such as zinc, lead, brass, and copper, have undesirable chemical reactions with certain liquids.These chemical reactions result in the formation of sludge, gums, carbon, or other deposits which clog openings, cause valves and pistons to stick or leak, and give poor lubrication to moving parts. Once a small amount of sludge or other deposits is formed, the rate of formation generally increases more rapidly. As these deposits are formed, certain changes in the physical and chemical properties of the liquid take place. The liquid usually becomes darker, the viscosity increases and damaging acids are formed.The extent to which changes occur in different liquids depends on the type of liquid, type of refining, and whether it has been treated to provide further resistance to oxidation. The stability of liquids can be improved by the addition of oxidation inhibitors. Inhibitors selected to improve stability must be compatible with the other required properties of the liquid.FREEDOM FROM ACIDITYAn ideal hydraulic liquid should be free from acids which cause corrosion of the metals in the system. Most liquids cannot be expected to remain completely no corrosive under severe operating conditions. The degree of acidity of a liquid, when new, may be satisfactory; but after use, the liquid may tend to become corrosive as it begins to deteriorate.Many systems are idle for long periods after operating at high temperatures. This permits moisture to condense in the system, resulting in rust formation.Certain corrosion- and rust-preventive additives are added to hydraulic liquids. Some of these additives are effective only for a limited period. Therefore, the best procedure is to use the liquid specified for the system for the time specified by the system manufacturer and to protect the liquid and the system as much as possible from contamination by foreign matter, from abnormal temperatures, and from misuse.FLASHPOINTFlashpoint is the temperature at which a liquid gives off vapor in sufficient quantity to ignite momentarily or flash when a flame is applied. A high flashpoint is desirable for hydraulic liquids because it provides good resistance to combustion and a low degree of evaporation at normal temperatures. Required flashpoint minimums vary from 300°F for the lightest oils to 510°F for the heaviest oils.FIRE POINTFire point is the temperature at which a substance gives off vapor in sufficient quantity to ignite and continue to burn when exposed to a spark or flame. Like flashpoint, a high fire point is required of desirable hydraulic liquids.MINIMUM TOXICITYToxicity is defined as the quality, state, or degree of being toxic or poisonous. Some liquids contain chemicals that are a serious toxic hazard. These toxic or poisonous chemicals may enter the body through inhalation, by absorption through the skin, or through the eyes or the mouth. The result is sickness and, in some cases, death. Manufacturers of hydraulic liquids strive to produce suitable liquids that contain no toxic chemicals and, as a result, most hydraulic liquids are free of harmful chemicals. Some fire-resistant liquids are toxic, and suitable protection and care in handling must be provided.DENSITY AND COMPRESSIBILITYA fluid with a specific gravity of less than 1.0 is desired when weight is critical, although with proper system design, a fluid with a specific gravity greater than one can be tolerated. Where avoidance of detection by military units is desired, a fluid which sinks rather than rises to the surface of the water is desirable. Fluids having a specific gravity greater than 1.0 are desired, as leaking fluid will sink, allowing the vessel with the leak to remain undetected.Recall from chapter 2 that under extreme pressure a fluid may be compressed up to 7 percent of its original volume. Highly compressible fluids produce sluggish system operation. This does not present a serious problem in small, low-speed operations, but it must be considered in the operating instructions.FOAMING TENDENCIESFoam is an emulsion of gas bubbles in the fluid. Foam in a hydraulic system results fromcompressed gases in the hydraulic fluid. A fluid under high pressure can contain a large volume of air bubbles. When this fluid is depressurized, as when it reaches the reservoir, the gas bubbles in the fluid expand and produce foam. Any amount of foaming may cause pump cavitations and produce poor system response and spongy control. Therefore, defaming agents are often added to fluids to prevent foaming. Minimizing air in fluid systems is discussed later in this chapter.CLEANLINESSCleanliness in hydraulic systems has received considerable attention recently. Some hydraulic systems, such as aerospace hydraulic systems, are extremely sensitive to contamination. Fluid cleanliness is of primary importance because contaminants can cause component malfunction, prevent proper valve seating, cause wear in components, and may increase the response time of servo valves. Fluid contaminants are discussed later in this chapter.The inside of a hydraulic system can only be kept as clean as the fluid added to it. Initial fluid cleanliness can be achieved by observing stringent cleanliness requirements (discussed later in this chapter) or by filtering all fluid added to the system.TYPES OF HYDRAULIC FLUIDSThere have been many liquids tested for use in hydraulic systems. Currently, liquids being used include mineral oil, water, phosphate ester, water-based ethylene glycol compounds, and silicone fluids. The three most common types of hydraulic liquids are petroleum-based, synthetic fire-resistant, and water-based fire-resistant.PETROLEUM-BASED FLUIDSThe most common hydraulic fluids used in shipboard systems are the petroleum-based oils. These fluids contain additives to protect the fluid from oxidation (antioxidant), to protect system metals from corrosion (anticorrosion), to reduce tendency of the fluid to foam (foam suppressant), and to improve viscosity.Petroleum-based fluids are used in surface ships，electro hydraulic steering and deck machinery systems, submarines，hydraulic systems, and aircraft automatic pilots, shock absorbers, brakes, control mechanisms, and other hydraulic systems using seal materials compatible with petroleum-based fluids.SYNTHETIC FIRE-RESISTANT FLUIDS Petroleum-based oils contain most of the desired properties of a hydraulic liquid. However, they are flammable under normal conditions and can become explosive when subjected to high pressures and a source of flame or high temperatures. Nonflammable synthetic liquids have been developed for use in hydraulic systems where fire hazards exist.Phosphate Ester Fire-Resistant FluidPhosphate ester fire-resistant fluid for shipboard use is covered by specification MIL- H-19457. There are certain trade names closely associated with these fluids. However, the only acceptable fluids conforming to MIL-H-19457 are the ones listed on the current Qualified Products List (QPL) 19457. These fluids will be delivered in containers marked MIL-H-19457C or a later specification revision. Phosphate ester in containers marked by a brand name without specification identification must not be used in shipboard systems, as they may contain toxic chemicals.These fluids will burn if sufficient heat and flame are applied, but they do not support combustion. Drawbacks of phosphate ester fluids are that they will attack and loosen commonly used paints and adhesives, deteriorate many types of insulations used in electrical cables, and deteriorate many gasket and seal materials. Therefore, gaskets and seals for systems in which phosphate ester fluids are used are manufactured of specific materials. Naval Ships，Technical Manual, chapter 262, specifies paints to be used on exterior surfaces of hydraulic systems and components in which phosphate ester fluid is used and on ship structure and decks in the immediate vicinity of this equipment. Naval Ships，Technical Manual, chapter 078, specifies gasket and seal materials used. NA V AIR 01-1A-17 also contains a list of materials resistant to phosphate ester fluids.Trade names for phosphate ester fluids, which do not conform to MIL-H-19457 include Pydraul、Skydrol、and Fire Safe.PHOSPHATE ESTER FLUID SAFETY.—as a maintenance person, operator, supervisor, or crew member of a ship, squadron, or naval shore installation, you must understand the hazards associated with hydraulic fluids to which you may be exposed.Phosphate ester fluid conforming to specification MIL-H-19457 is used in aircraft elevators, ballast valve operating systems, and replenishment-at-sea systems. This type of fluid contains a controlled amount of neurotoxic material. Because of the neurotoxic effects that can result from ingestion, skin absorption, or inhalation of these fluids, be sure to use the following precautions:1. Avoid contact with the fluids by wearing protective clothing.2. Use chemical goggles or face shields to protect your eyes.3. If you are expected to work in an atmosphere containing a fine mist or spray, wear a continuous-flow airline respirator.4. Thoroughly clean skin areas contaminated by this fluid with soap and water.5. If you get any fluid in your eyes, flush them with running water for at least 15 minutes and seek medical attention.If you come in contact with MIL-H-19457 fluid, report the contact when you seek medical aid and whenever you have a routine medical examination.Naval Ships，Technical Manual, chapter 262, contains a list of protective clothing, along with national stock numbers(NSN),for use with fluids conforming to MIL-H-19457.It also contains procedures for repair work and for low-level leakage and massive spills cleanup.PHOSPHATE ESTER FLUID DISPOSAL.—Waste MIL-H-19457 fluids and refuse (rags and other materials) must not be dumped at sea. Fluid should be placed in bung-type drums. Rags and other materials should be placed in open top drums for shore disposal. These drums should be marked with a warning label stating their content, safety precautions, and disposal instructions. Detailed instructions for phosphate ester fluids disposal can be found in Naval Ships, Technical Manual, chapter 262, and OPNA VINST 5090.1.Silicone Synthetic Fire-Resistant FluidsSilicone synthetic fire-resistant fluids are frequently used for hydraulic systems which require fire resistance, but which have only marginal requirements for other chemical or physical properties common to hydraulic fluids. Silicone fluids do not have the detrimental characteristics of phosphate ester fluids, nor do they provide the corrosion protection and lubrication of phosphate ester fluids, but they are excellent for fire protection. Silicone fluid conforming to MIL-S-81087 is used in the missile hold-down and lockout system aboard submarines.Lightweight Synthetic Fire-Resistant Fluids In applications where weight is critical, lightweight synthetic fluid is used in hydraulic systems. MIL-H-83282 is a synthetic, fire-resistant hydraulic fluid used in military aircraft and hydrofoils where the requirement to minimize weight dictates the use of a low-viscosity fluid. It is also the most commonly used fluid in aviation support equipment. NA V AIR 01-1A-17 contains additional information on fluids conforming to specification MIL-H-83282.WATER-BASED FIRE-RESISTANT FLUIDS The most widely used water-based hydraulic fluids may be classified as water-glycol mixtures and water-synthetic base mixtures. The water-glycol mixture contains additives to protect it from oxidation, corrosion, and biological growth and to enhance its load-carrying capacity.Fire resistance of the water mixture fluids depends on the vaporization and smothering effect of steam generated from the water. The water in water-based fluids is constantly being driven off while the system is operating. There- fore, frequent checks to maintain the correct ratio of water are important.The water-based fluid used in catapult retracting engines, jet blast deflectors, and weapons elevators and handling systems conforms to MIL-H-22072.The safety precautions outlined for phosphate ester fluid and the disposal of phosphate ester fluid also apply to water-based fluid conforming to MIL-H-22072.CONTAMINATIONHydraulic fluid contamination may be described as any foreign material or substance whose presence in the fluid is capable of adversely affecting system performance or reliability. It may assume many different forms, including liquids, gases, and solid matter of various compositions, sizes, and shapes. Solid matter is the type most often found in hydraulic systems and is generally referred to as particulate contamination. Con- termination is always present to some degree, even in new, unused fluid, but must be kept below a level that will adversely affect system operation. Hydraulic contamination control consists of requirements, techniques, and practices necessary to minimize and control fluid contamination.CLASSIFICATIONThere are many types of contaminants which are harmful to hydraulic systems and liquids. These contaminants may be divided into two different classes—particulate and fluid.Particulate ContaminationThis class of contaminants includes organic, metallic solid and inorganic solid contaminants. These contaminants are discussed in the following paragraphs.ORGANIC CONTAMINATION.—Organic solids or semisolids found in hydraulic systems are produced by wear, oxidation, or polymerization. Minute particles of O-rings, seals, gaskets, and hoses are present, due to wear or chemical reactions. Synthetic products, such as neoprene, silicones, and hypalon, though resistant to chemical reaction with hydraulic fluids, produce small wear particles. Oxidation of hydraulic fluids increases with pressure and temperature, although antioxidants are blended into hydraulic fluids to minimize such oxidation.The ability of a hydraulic fluid to resist oxidation or polymerization in service is defined as its oxidation stability. Oxidation products appear as organicacids,asphaltics,gums,and varnishes. These products combine with particles in the hydraulic fluid to form sludge. Some oxidation products are oil soluble and cause the hydraulic fluid to increase in viscosity; other oxidation products are not oil soluble and form sediment.METALLIC SOLID CONTAMINATION.—Metallic contaminants are almost always present in a hydraulic system and will range in size from microscopic particles to particles readily visible to the naked eye. These particles are the result of wearing and scoring of bare metal parts and plating materials, such as silver and chromium. Although practically all metals commonly used for parts fabrication and plating may be found in hydraulic fluids, themajor metallic materials found are ferrous, aluminum, and chromium particles. Because of their continuous high-speed internal movement, hydraulic pumps usually contribute most of the metallic particulate contamination present in hydraulic systems. Metal particles are also produced by other hydraulic system components, such as valves and actuators, due to body wear and the chipping and wearing away of small pieces of metal plating materials.INORGANIC SOLID CONTAMINATION.—This contaminant group includes dust, paint particles, dirt, and silicates. Glass particles from glass bead penning and blasting may also be found as contaminants. Glass particles are very undesirable contaminants due to their abrasive effect on synthetic rubber seals and the very fine surfaces of critical moving parts. Atmospheric dust, dirt, paint particles, and other materials are often drawn into hydraulic systems from external sources. For example, the wet piston shaft of a hydraulic actuator may draw some of these foreign materials into the cylinder past the wiper and dynamic seals, and the contaminant materials are then dispersed in the hydraulic fluid. Contaminants may also enter the hydraulic fluid during maintenance when tubing, hoses, fittings, and components are disconnected or replaced. It is therefore important that all exposed fluid ports be sealed with approved protective closures to minimize such contamination.Fluid ContaminationAir, water, solvent,and other foreign fluids are in the class of fluid contaminants.AIR CONTAMINATION.—Hydraulic fluids are adversely affected by dissolved, entrained, or free air. Air may be introduced through improper maintenance or as a result of system design. Any maintenance operation that involves breaking into the hydraulic system, such as disconnecting or removing a line or component will invariably result in some air being introduced into the system. This source of air can and must be minimized by prebilling replacement components with new filtered fluid prior to their installation. Failing to prefill a filter element bowl with fluid is a good example of how air can be introduced into the system. Although prebilling will minimize introduction of air, it is still important to vent the system where venting is possible.Most hydraulic systems have built-in sources of air. Leaky seals in gas-pressurized accumulators and reservoirs can feed gas into a system faster than it can be removed, even with the best of maintenance. Another lesser known but major source of air is air that is sucked into the system past actuator piston rod seals. This usually occurs when the piston rod is stroked by some external means while the actuator itself is not pressurized.WATER CONTAMINATION.—Water is a serious contaminant of hydraulic systems. Hydraulic fluids are adversely affected by dissolved, emulsified, or free water. Water contamination may result in the formation of ice, which impedes the operation of valves,actuators, and other moving parts. Water can also cause the formation of oxidation products and corrosion of metallic surfaces.SOLVENT CONTAMINATION.—Solvent contamination is a special form of foreign fluid contamination in which the original contaminating substance is a chlorinated solvent. Chlorinated solvents or their residues may, when introduced into a hydraulic system, react with any water present to form highly corrosive acids.Chlorinated solvents, when allowed to combine with minute amounts of water often found in operating hydraulic systems, change chemically into hydrochloric acids. These acids then attack internal metallic surfaces in the system, particularly those that are ferrous, and produce a severe rust-like corrosion. NA V AIR 01-1A-17 and NSTM, chapter 556, contain tables of solvents for use in hydraulic maintenance.FOREIGN-FLUIDS CONTAMINATION.—Hydraulic systems can be seriously contaminated by foreign fluids other than water and chlorinated solvents. This type of contamination is generally a result of lube oil, engine fuel, or incorrect hydraulic fluid being introduced inadvertently into the system during servicing. The effects of such contamination depend on the contaminant, the amount in the system, and how long it has been present.NOTE: It is extremely important that the different types of hydraulic fluids are not mixed in one system. If different type hydraulic fluids are mixed, the characteristics of the fluid required for a specific purpose are lost. Mixing the different types of fluids usually will result in a heavy, gummy deposit that will clog passages and require a major cleaning. In addition, seals and packing installed for use with one fluid usually are not compatible with other fluids and damage to the seals will result.ORIGIN OF CONTAMINATIONRecall that contaminants are produced from wear and chemical reactions, introduced by improper maintenance, and inadvertently introduced during servicing. These methods of contaminant introduction fall into one of the four major areas of contaminant origin.1. Particles originally contained in the system. These particles originate during the fabrication and storage of system components. Weld spatter and slag may remain in welded system components, especially in reservoirs and pipe assemblies. The presence is minimized by proper design. For example, seam-welded overlapping joints are preferred, and arc welding of open sections is usually avoided. Hidden passages in valve bodies, inaccessible to sand blasting or other methods of cleaning, are the main source of introduction of core sand. Even the most carefully designed and cleaned castings will almost invariably free some sand particles under the action of hydraulic pressure. Rubber hose assemblies always contain some loose particles. Most of these particles can be removed by flushing the hose before installation;。
液压系统和气压系统外文文献翻译、中英文翻译
液压系统和气压系统外文文献翻译、中英文翻译Hydraulic system and Peumatic SystemHui-xiong wan1,Jun Fan2Abstract:Hydraulic system is widely used in industry, such as stamping, grinding of steel type work and general processing industries, agriculture, mining, space technology, deep sea exploration, transportation, marine technology, offshore gas and oil exploration industries, in short, Few people in their daily lives do not get certain benefits from the hydraulic technology. Successful and widely used in the hydraulic system's secret lies in its versatility and ease of maneuverability. Hydraulic power transmission mechanical systems as being not like the machine geometry constraints, In addition, the hydraulic system does not like the electrical system, as constrained by the physical properties of materials, it passed almost no amount of power constraints.Keywords: Hydraulic system,Pressure system,FluidThe history of hydraulic power is a long one, dating from man’s prehistoric efforts to harness the energy in the world around him. The only source readily available were the water and the wind—two free and moving streams.The watermill, the first hydraulic motor, was an early invention. One is pictured on a mosatic at the Great Palace in Byzantium, dating from the early fifth century. The mill had been built by the Romans. But the first record of a watermill goes back even further, to around 100BC, and the origins may indeed have been much earlier. The domestication of grain began some 5000 years before and some enterprising farmer is bound to have become tired of pounding or grinding the grain by hand. Perhaps,in fact, the inventor were some farmer’s wives. Since the often drew the heavy jobs.Fluid is a substance which may flow; that is, its constituent particles may continuously change their positions relative to one another. Moreover, it offers no lasting resistance to the displacement, however great, of one layer over another. This means that, if the fluid is at rest, no shear force (that is a force tangential to the surface on which it acts) can exist in it.Fluid may be classified as Newtonian or non--Newtonian. In Newtonian fluid there is a linear relation between the magnitude of applied shear stresses and the resulting rate of angular deformation. In non—Newtonian fluid there is a nonlinear relation between the magnitude of applied shear stress and the rate of angulardeformation.The flow of fluids may be classified in many ways, such as steady or non steady, rotational or irrotational, compressible or incompressible, and viscous or no viscous.All hydraulic systems depend on Pascal’s law, such as steady or pipeexerts equal force on all of the surfaces of the container.In actual hydraulic systems, Pas cal’s law defines the basis of results which are obtained from the system. Thus, a pump moves the liquid in the system. The intake of the pump is connected to a liquid source, usually called the tank or reservoir. Atmospheric pressure, pressing on the liquid in the reservoir, forces the liquid into the pump. When the pump operates, it forces liquid from the tank into the discharge pipe at a suitable pressure.The flow of the pressurized liquid discharged by the pump is controlled by valves. Three control functions are used in most hydraulic systems: (1) control of the liquid pressure, （2）controlof the liquid flow rate, and (3) control of the direction of flow of the liquid.Hydraulic drives are used in preference to mechanical systems when(1) powers is to be transmitted between point too far apart for chains or belts; (2) high torque at low speed in required; (3) a very compact unit is needed; (4) a smooth transmission, free of vibration, is required;(5) easy control of speed and direction is necessary; and (6) output speed is varied steplessly.Fig. 1 gives a diagrammatic presentation of the components of a hydraulic installation. Electrically driven oil pressure pumps establish an oil flow for energy transmission, which is fed to hydraulic motors or hydraulic cylinders, converting it into mechanical energy. The control of the oil flow is by means of valves. The pressurized oil flow produces linear or rotary mechanical motion. The kinetic energy of the oil flow is comparatively low, and therefore the term hydrostatic driver is sometimes used. There is little constructional difference between hydraulic motors and pumps. Any pump may be used as a motor. The quantity of oil flowing at any given time may be varied by means of regulating valves( as shown in Fig.7.1) or the use of variable-delivery pumps.The application of hydraulic power to the operation of machine tools is by no means new, though its adoption on such a wide scale as exists at present is comparatively recent. It was in fact in development of the modern self-contained pump unit that stimulated the growth of this form of machine tool operation.Hydraulic machine tool drive offers a great many advantages. One of them is that it can give infinitely-variable speed control over wide ranges. In addition, they can change the direction ofdrive as easily as they can vary the speed. As in many other types of machine, many complex mechanical linkages can be simplified or even wholly eliminated by the use of hydraulics.The flexibility and resilience of hydraulic power is another great virtue of this form of drive. Apart from the smoothness of operation thus obtained, a great improvement is usually found in the surface finish on the work and the tool can make heavier cuts without detriment and will last considerably longer without regrinding.Hydraulic and pneumatic systemThere are only three basic methods of transmitting power:electrical,mechanical,and fluid power.Most applications actually use a combination of the three methods to obtain the most efficient overall system. To properly determine which principle method to use,it is important to know the salient features of each type. For example, fluid systems can transmit power more economically over greater distances than can mechanical types. However, fluid systems are restricted to shorter distances than are electrical systems.Hydraulic power transmission system are concerned with the generation, modelation, and control of pressure and flow，and in general such systems include:1.Pumps which convert available power from the prime mover to hydraulic power at the actuator.2.Valves which control the direction of pump-flow, the level of power produced, and the amount of fluid-flow to the actuators. The power level is determined by controlling both the flow and pressure level.3.Actcators which convert hydtaulic power to usable mechanical power output at the point required.4.The medium, which is a liquid, provides rigid transmission and control as well as lubrication of componts, sealing in valves, and cooling of the system.5.Conncetots which link the various system components, provide power conductors for the fluid under pressure, and fluid flow return to tank(reservoir).6.Fluid storage and conditioning equipment which ensure sufficient quality and quantity as well as cooling of the fluid.Hydraulic systems are used in industrial applications such as stamping presses, steel mills, and general manufacturing, agricultural machines, mining industry,aviation, space technology, deep-sea exploration, transportion, marine technology, and offshore gas and petroleum exploration. In short, very few people get through a day of their lives without somehow benefiting from the technology of hydraulicks.The secret of hydraulic system’s success and widespread use is its versatility and manageability. Fluid power is not hindered by the geometry of the machine as is the case in mechanical systems. Also, power can be transmitted in almost limitless quantities because fluid systems are not so limited by the physical limitations of materials as are the electrical systems. For example, the performance of an electromangnet is limited by the saturation limit of steel. On the other hand, the power limit of fluid systems is limited only by the strength capacity of the material.Industry is going to depend more and more on automation in order to increase productivity. This includes remote and direct control of production operations, manufacturing processes, and materials handling. Fluid power is the muscle of automationbecause of advantages in the following four major categories.1.Ease and accuracy of control. By the use of simple levers and push buttons, the operator of a fluid power system can readily start, stop, speed up or slow down, and position forces which provide any desired horsepower with tolerances as precise as one ten-thousandth of an inch.2.Multiplication of force. A fluid power system(without using cumbersome gears, pulleys, and levers) can multiply forces simply and efficiently from a fraction of an ounce to several hundred tons of output.3.Constant force or torque. Only fluid power systems are capable of providing contant force or torque regardless of speed changes. This is accomplished whether the work output moves a few inches per hour, several hundred inches per minute, a few revolutions per hour, or thousands of revolutions per minute.4.Simplicity, safely, economy. In general, fluid power systems use fewer moving parts than comparable mechanical or electrical systems. Thus, they are simpler to maintain and operate. This, in turn, maximizes safety, companctness, and reliability. For example, a new power steering control designed has made all other kinds of power systems obsolete on many off-highway vehicles. The steering unit consists of a manually operated directional control valve and meter in a single body. Because the steering unit is fully fluid-linked, mechanical linkages, universal joints, bearings, reduction gears, etc, are eliminated. This provides a simple, compact system. In addition, very little input torque is required to produce the control needed for the toughest applications. This is important where limitations of control space require a small steering wheel and it becomes necessary to reduce operatot\r fatique.Additonal benefits of fluid power systems include instantly reversible motion, automatic protection against overloads, and infinitely variable speed control. Fluid power systems also have the highest horsepower per weight ratio of any known power source. In spite of all these highly desirable features of fluid power, it is not a panacea for all power transmission problems. Hydraulic systems also have some drawbacks. Hydraulic oils are messy, and leakage is impossible to completely eliminate. Also, most hydraulic oils can cause fires if an oils occurs in an area of hot equipment.Peumatic SystemPneumatic systems use pressurized gases to tansmit and control power. A s the name implies, pneumatic systems typically use air(rather than some other gas) as the fluid medium because air is a safe, low-cost, and readily available fluid. It is particularly safe in environments where an electrical spark could ignite leaks from system components.In pneumatic systems ,compressors are used to compress and supply the necessary quantities of air. Compressors are typically of the piston, vane or screw type. Basically a compressor increases the pressure of a gas by reducing its volume as described by the perfect gas laws.Pneumatic systems normally use a large centralized air compressor which is considered to be an infinite air source similar to an electrical system where you merely plug into an electrical outlut for electricity. In this way, pressurized air can be piped from one source to various locations throughout an entire industrial plant. The air then flows through a pressue regulator which redeces the pressure to the desired level for the particular circuit application. Because air is not a good lubircant（contains about 20% oxygen）, pneumaticssystems required a lubricator to inject a very fine mist of oil into the air discharging from the pressure regulator. This prevents wear of the closely fitting moving parts of pneumatic components.Free air from the atmosphere contains varying amounts of moisure. This moisure can be harmful in that it can wash away lubricants and thus cause excessive wear and corrosion. Hence ,in some applications ,air driers are needed to remove this undesirable moisture. Since pneumatics systems exhaust directly into the atmosphere, they are capable of generating excessive noise. Therefore, mufflers are mounted on exhaust ports of air valves and actuators to reduce noise and prevent operating personnel from injury resulting not only from exposure to noise but also from high-speed airborne particles.There are several reasons for considering the use of pneumatic systems instead of hydraulic systems. Liquids exhibit greater inertia than do gases. Therefore, in hydraulic systems the weight of oil is a potential problem when accelerating and decelerating actuators and when suddenly opening and closing valves. Due to Newton’s law of motion(force equals mass multiplied by acceleration), the force required to accelerate oil is many times greater than that required to accelerate an equal volume of air. Liquids also exhibit greater viscosity than do gases. This results in larger frictional pressure and power losses. Also ,since hydraulic systems use a fluid foreign to the atmosphere, they require special reservoirs and noleak system designs. Pneumatic system use air which is exhausted directly back into the surrounding environment. Generally speaking, pneumatic systems are less expensive than hydraulic systems.However, because of the compressibility of air, it isimpossible to obtain precise controlled actuator velocities with pneumatic systems. Also, precise positioning control is not obtainable. While pneumatics pressures are quite low due to compressor design limitations(less than 250 psi), hydraulic pressures can be as high as 10000 psi. Thus, hydraulics can be high-power systems, whereas pneumatics are confined to low-power applications. Industrial applications of pneumatics systems are growing at a rapid pace. Typical examples include stamping, drilling, hoist, punching, clamping, assembling, riveting, materials handling, and logic controlling operations.液压系统和气压系统万辉雄1，范军2摘要：液压系统在工业中应用广泛，例如冲压、钢类工件的磨削及一般加工业、农业、矿业、航天技术、深海勘探、运输、海洋技术，近海天然气和石油勘探等行业，简而言之，在日常生活中很少有人不从液压技术得到某些益处。
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液压系统外文翻译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1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。
齿轮泵的概念是很简单的，即它的最基本形式就是两个尺寸相同的齿轮在一个紧密配合的壳体内相互啮合旋转，这个壳体的内部类似“8”字形，两个齿轮装在里面，齿轮的外径及两侧与壳体紧密配合。
来自于挤出机的物料在吸入口进入两个齿轮中间，并充满这一空间，随着齿的旋转沿壳体运动，最后在两齿啮合时排出。
在术语上讲，齿轮泵也叫正排量装置，即像一个缸筒内的活塞，当一个齿进入另一个齿的流体空间时，液体就被机械性地挤排出来。
因为液体是不可压缩的，所以液体和齿就不能在同一时间占据同一空间，这样，液体就被排除了。
由于齿的不断啮合，这一现象就连续在发生，因而也就在泵的出口提供了一个连续排除量，泵每转一转，排出的量是一样的。
随着驱动轴的不间断地旋转，泵也就不间断地排出流体。
泵的流量直接与泵的转速有关。
实际上，在泵内有很少量的流体损失，这使泵的运行效率不能达到100,，因为这些流体被用来润滑轴承及齿轮两侧，而泵体也绝不可能无间隙配合，故不能使流体100,地从出口排出，所以少量的流体损失是必然的。
然而泵还是可以良好地运行，对大多数挤出物料来说，仍可以达到93,,98,的效率。
对于粘度或密度在工艺中有变化的流体，这种泵不会受到太多影响。
如果有一个阻尼器，比如在排出口侧放一个滤网或一个限制器，泵则会推动流体通过它们。
如果这个阻尼器在工作中变化，亦即如果滤网变脏、堵塞了，或限制器的背压升高了，则泵仍将保持恒定的流量，直至达到装置中最弱的部件的机械极限(通常装有一个扭矩限制器)。
对于一台泵的转速，实际上是有限制的，这主要取决于工艺流体，如果传送的是油类，泵则能以很高的速度转动，但当流体是一种高粘度的聚合物熔体时，这种限制就会大幅度降低。
推动高粘流体进入吸入口一侧的两齿空间是非常重要的，如果这一空间没有填充满，则泵就不能排出准确的流量，所以PV 值(压力×流速)也是另外一个限制因素，而且是一个工艺变量。
由于这些限制，齿轮泵制造商将提供一系列产品，即不同的规格及排量(每转一周所排出的量)。
这些泵将与具体的应用工艺相配合，以使系统能力及价格达到最优。
PEP,II泵的齿轮与轴共为一体，采用通体淬硬工艺，可获得更长的工作寿命。
“D”型轴承结合了强制润滑机理，使聚合物经轴承表面，并返回到泵的进口侧，以确保旋转轴的有效润滑。
这一特性减少了聚合物滞留并降解的可能性。
精密加工的泵体可使“D”型轴承与齿轮轴精确配合，确保齿轮轴不偏心，以防齿轮磨损。
Parkool密封结构与聚四氟唇型密封共同构成水冷密封。
这种密封实际上并不接触轴的表面，它的密封原理是将聚合物冷却到半熔融状态而形成自密封。
也可以采用Rheoseal密封，它在轴封内表上加工有反向螺旋槽，可使聚合物被反压回到进口。
为便于安装，制造商设计了一个环形螺2栓安装面，以使与其它设备的法兰安装相配合，这使得筒形法兰的制造更容易。
PEP,II齿轮泵带有与泵的规格相匹配的加热元件，可供用户选配，这可保证快速加温和热量控制。
与泵体内加热方式不同，这些元件的损坏只限于一个板子上，与整个泵无关。
齿轮泵由一个独立的电机驱动，可有效地阻断上游的压力脉动及流量波动。
在齿轮泵出口处的压力脉动可以控制在1,以内。
在挤出生产线上采用一台齿轮泵，可以提高流量输出速度，减少物料在挤出机内的剪切及驻留时间，降低挤塑温度及压力脉动以提高生产率及产品质量。
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3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。