机械专业毕业设计外文翻译--什么是液压
【机械专业中文翻译】液压缸
毕业设计(论文)外文资料翻译系部：机械工程系专业：机械工程及自动化姓名：学号：外文出处：HYDRAULICS ANDPNEUMATICS TRANSMISSIONPage38--44附件： 1.外文资料翻译译文；2.外文原文。
指导教师评语：该同学查阅大量资料，完成翻译。
译文正确地表达了原文的意义、概念描述符合汉语的习惯，语句通畅，层次很清晰。
成绩评定为优。
签名：年月日附件1：外文资料翻译译文液压缸3.1 液压缸的分类及基本计算液压缸是液压传动系统中应用最多的执行元件,它将油液的压力能转换为机械能,实现往复直线运动或摆动,输出力或扭矩；其作用方式可分为单作用式和双作用式两种,单作用式液压缸只能实现单用运动,即压力油只是通向液压缸的一腔,而反方向运动则必须依靠外力来实现,如复位弹簧力,自重或其它外部作用；双作用式液压缸在两个方向上的运动都由油压力推动来实现,可实现双向运动。
液压缸可以看作是直线马达(或摆动马达),其单位位移排量即为液压缸的有效面积A ,当液压缸的回油压力为零且不计损失时,输出速度v 等于输入注量q 除以排量A,输出推力F 等于输入压力p 乘以排量A,即输入液压功率pq 等于输入机械功率Fv 。
液压缸有多种结构,但根据其具体结构特点可分为活塞式、柱塞式和摆动式三类基本形式,除此以外,还有在基本形式上发展起来各种特殊用途的组合液压缸,下面分别予以介绍。
3.1.1 活塞式液压缸活塞式液压缸可分为双杆式和单杆式两种结构形式,其安装方式有缸筒固定和活塞杆固定两种形式。
3.1.1.1 双杆活塞式液压缸图3.1所示为双杆活塞式液压缸的工作原理图,活塞两侧都有活塞杆伸出。
当两活塞杆直径相同,供油压力和流量不变时,活塞式液压缸在两个方向上的运动速度和推力都相等,即 )(422d D q A q v v -==πηην (3.1) ηπm p p d D F ))((42122--= (3.2)图3.1 双杆活塞式液压缸式中 v----液压缸的运动速度)/(s m ；F ----液压缸的推力)(N ；νη----液压缸的容积效率；m η----液压缸的机械效率；q ----液压缸的流量)/(3s m ；A ----液压缸的有效工作面积)(2m ；p 1----进油压力)(Pa ；2p ----回油压力)(Pa ； D ----活塞直径)(m ；d ----活塞杆直径)(m 。
液压专业毕业设计外文翻译有译文外文文献值得收藏哦
外文原文：The Analysis of Cavitation Problems in the Axial Piston Pumpshu WangEaton Corporation，14615 Lone Oak Road,Eden Prairie，MN 55344This paper discusses and analyzes the control volume of a piston bore constrained by the valve plate in axial piston pumps。
The vacuum within the piston bore caused by the rise volume needs to be compensated by the flow; otherwise, the low pressure may cause the cavitations and aerations。
In the research, the valve plate geometry can be optimized by some analytical limitations to prevent the piston pressure below the vapor pressure。
The limitations provide the design guide of the timings and overlap areas between valve plate ports and barrel kidneys to consider the cavitations and aerations。
_DOI: 10。
1115/1.4002058_ Keywords: cavitation ，optimization, valve plate，pressure undershoots 1 IntroductionIn hydrostatic machines，cavitations mean that cavities or bubbles form in the hydraulic liquid at the low pressure and collapse at the high pressure region, which causes noise，vibration，and less efficiency.Cavitations are undesirable in the pump since the shock waves formed by collapsed may be strong enough to damage components. The hydraulic fluid will vaporize when its pressure becomes too low or when the temperature is too high. In practice，a number of approaches are mostly used to deal with the problems：（1) raise the liquid level in the tank，(2）pressurize the tank, （3）booster the inlet pressure of the pump，（4) lower the pumping fluid temperature，and （5) design deliberately the pump itself.Many research efforts have been made on cavitation phenomena in hydraulic machine designs。
机械制造专业外文翻译--柔韧力液压设备维修和机械加工
外文原文：HYDRAULIC EQUIPMENT OF PLIABLE FORCE FOR MAINTENANCEAND MECHANICAL WORKINGAbstract.The collaboration between the Hydraulic and Pneumatic Acting Systems Engineering Department and the SC HYDRAMOLD SRL firm led to the realization of some performances products on the hydraulics and pneumatics segment.The paper proposes to offer the most representative hydraulic pliable equipments force for mechanical working and maintenance.A big part from the hydraulic equipments is patented or claim of patent,the technology and technological originality being totally part of those.Because the paper has a prevalent technical character,in the presentation will be got off especially the performance characteristics of the areas used and the hydraulic equipments advantages of the pliable force.Key words:hydraulic equipment,maintenance,mecanical working.1.IntroductionThe multi-functional modular equipments,pliable,for mechanical working, that are based on the hydraulic drive are destined to the manufacturing plant IMM also to the manufacturing plant of maintenance of the big company framework from energetic,petrochemistry,transport.All the equipments what are adduced in work are submitted in the framework of DISAHP research and make the study of other papers.Taking account the finite space of a work,there will be proposed from the large palette of hydraulic pliable equipments force a new or modernized equipments series from each segment developed by the SC HYDRAMOLD SRL firm(pressure sources,hydraulic presses,hydraulic tools, hydraulic equipment of 3000 bar,hydraulic lift equipment),following as in the next works it will be published other modern hydraulic equipments.2.Hydraulic Equipments Analysis Force2.1 Pressure SourcesThe pressure sources of the force hydraulic equipments yielded by the SCHYDRAMOLD SRL are:the hydraulic acting units that have electric or thermal engine and the hydraulic manual or pedal pumps.·Hydraulic drive unit description with electric engineThe electro-hydraulic drive units HUEH are high pressure sources for the hydraulic cylinder supplying with simple or double action from some equipments structure,hydraulic installations or appliances,and they work with relative small rate flow and pressures of until 700 bars,(Fig.1).The working developed pressure can be adjusted depending on task:30-700 bar.Fig.1–The electro-hydraulic drive unit[1]1-electric engine;2-multiplier;3-oil receiver;4-operator’s desk.Table 1·AdvantagesThe electro-hydraulic drive unit advantages(HUEH)are:they offer the possibility to maintain into the pressure,respectively the hydraulic obstruct of the task and dispose of a precise setting of the pressure depending on the task until 700 bar;it allows the permanent control of the cylinder stroke and also the automatic commutation from the first step to the second pressure step respectively from the fast start to the technological breakthrough;it allows electric remote command,while the charging voltage is of 24 Vcc,having the oil temperature monitoring possibility and the automatic disconnect to the value of 55°C;it has the hydraulic components of the hydraulic panel(pump,valve, slide valve)and it functions in optimal behavior to maximumfrom the half nominal pressure,providing for advanced reliability;it has a low level noise (under70 db);it confers the simultaneous supplying possibility of 2,3 or 4 cylinders-through to an attached branch[2,3].·The hydraulic drive unit description with heat engineThe hydraulic drive units with heat engine(HUMUTH)proceed from the new products scale with a distinguished resilience into the field,and they function with small flow rate and pressures of until 700 bar,(fig.2).Fig.2–The hydraulic drive unit with heat engine[4]1-heat engine;2-multiplier;3-operator’s de sk;4-oil receiver.Table 2The hydraulic drive unit characteristics with heat engine[1].The hydraulic drive unit with heat engine has a manual command for thestart and thechanging of the pressure steps from the 1st step to the 2nd step itmakes manual too[4].·AdvantagesThe hydraulic drive unit offers similar advantages with those presented at the hydraulic drive unit with electric engine.The additional advantage consists of the mobility into the field as the result of a low weight and it doesn’t depe nd of a fixed power source(for example the connected of the unit to the line system).2.2.Hydraulic PressesThe hydraulic press workshop HPH-075 is composed from a stand shut framework(fixed top traverse columns,adjustable bottom traverse,basic plate) removable,a hydraulic cylinder with double action HCHD-075.150 installed on a transversal carriage,a plates set,pressing bolts and nuts,(Fig.3).Fig.3.–The hydraulic press 75[tf]1-Basic plate;2-Columns;3-Bottom traverse;4-Hydraulic cylinder HCHD-075.125;5-Top traverse;6-Pressing bolts;7-Pressing plates.Table 3The hydraulic press characteristics[1].Among the direct applications of this hydraulic presses deserve reminded: pressing and gear puller off of the transmission shafts from the gear boxes; pressing and puller ball bearings from the attack pinions from the tapering groups;pressing and extraction from jammed subsets;cold deformation for various proof sample.·AdvantagesThe hydraulic press has a modular construction,removable,having an indexed settlement system of the inferior traverse,at the various determinate heights of range of 75[mm].The transverse carriage of press represents an easy settlement system of the hydraulic cylinder position allowing thus the pressing axle regulation;The hydraulic press has plates set,bolts and pressing nuts for the realization of all technological operations;From the press project result an optimal report between its weight and achieved force owing to the acting to maximum pressures 700 bar,as effect of a reduced weight it is easy of carried.2.3.Hydraulic toolsThe hydraulic tool scale used in the mechanical processing and maintenance is various,with many applications in the mechanical engineering.There are reminded among these hydraulic tools:the device of the bending pipes and the hydraulic device of cutting.·The Device Description of Bending PipesThe bending template,fixed on acting rod of the hydraulic cylinder and having the suitableskewers profile so pipe dimension as well as inflexion beam,it will act over pipe that follows to be distorted;the pipe guides on the two ferries of the rest,fixed between the device plates.The superior plate of the appliance it can bate to allow the introduction of the template and of the ferries of the rest(Fig.5).The device of bending pipes type HDIT.M-020.300 is an equipment, hydraulic driven and it is destined to the bending at cold of the installations pipes in the maintenance and repairs sectors.Table 4The device characteristics of bending pipes[1]Fig.5.–The device of bending pipes[1]1- Tripod;2-Fixed plate;3-Turnover plate;4-Bolt;5-Hydraulic cylinder HCHD-020.300,6-Form.Table 5The working characteristics of device of bending pipes HDIT.M-020.300[1]·The Hydraulic Device Description of Cutting 20[tf]The device is formed from a metallic body,realized through welded construction,a hydraulic cylinder with simple action HCHS-020.028,a movable knife jointly mounted with the cylinder rod and a fixed knife body, (Fig.6).The hydraulic cylinder acting it realizes through the connection to a highpressure source(manual pump HPHM-700 or hydraulic pedal pump HPHP-700),through a fast coupling and hydraulic flexible pipe.The semi-finished product it installs between the two knives,while the cutting knife and the counter-knife establish the debiting of the semi-finished product from the steel.The retirement of the cutting knife it realizes by a spring incorporated into a cylinder.The hydraulic device of cutting HFMO-020.028 is a hydraulic drive device,used in the producing processes and maintenance with the view of cuttings at cold of the circular,square,hexagonal and flat bars steel.The movable knife run is of 28[mm]and the maximum pressure 700[bar],[1].Fig.6.–The hydraulic device of cutting 20[tf]1--2-Movable knife;3-Fixed knife;4-Feed nipple with oil under pressure.Table 6The working characteristics of hydraulic device of cutting type HFMO-020.028,[1].·AdvantagesThere are important to notice,among the hydraulic device advantages of cutting:the compact structure and modern design;the easy drivability and the reduced weight;it eliminates the useless physicals work of the operator;it lowers the appropriated time procedure.Scaling Behaviour of Pressure-Driven Micro-Hydraulic SystemsABSTRACTThis paper presents a lumped network approach for the modelling and design of micro-hydraulic systems.A hydraulic oscillator has been built consisting of hydraulic resistors,capacitors and transistors(pressure controlled valves).The scaling of micro-hydraulic networks consisting of linear resistors,capacitors and inertances has been studied.An important result is that to make smaller networks faster,driving pressures should increase with reducing size.1 INTRODUCTIONMicro-hydraulic systems can be modeled and designed using a generalized physical system description[1,2].This approach is based on the assumption that it is possible to separate and concentrate properties of a system into interconnected subsystems.It has proven its great value in the design of electronic circuits.The lumped network approach also offers a powerful design tool for microfluidic systems[3-5].To illustrate the far-reaching analogy between different physical domains,we have rebuilt an electronic astable multivibrator network in the hydraulic domain[4].The system consists of hydraulic capacitors, resistors,transistors and(parasitic)coils.Based on this micro-hydraulic system the scaling behaviour of low Re (Reynolds number)hydraulic systems has been analyzed.2 HYDRAULIC FUNDAMENTALSIn every physical domain a conserved quantity q can be distinguished[1].The flow is the rate of exchange of this conserved quantity between subsystems.In the hydraulic domain the flow variable is the volume flow.The effort is the tension that governs the exchange of the conserved quantity between subsystems.In the hydraulicdomain the effort variable is the pressure p[Pa].2.1 Hydraulic ResistorsThe hydraulic resistor physically is a liquid flow restriction,symbolically represented as in fig.1a.For a linear flow resistor,the resistance R is defined by:Where p12=p1–p2 is the pressure drop across the resistor, and the volume flow through the resistor.At sufficient low Re the flow in a duct is laminar and fully developed (Poisseuille flow),and the pressure drop p across the duct is proportional to the volume flow rate.For aduct of arbitrary cross section the resistance is given by[6]:Where f is the Fanning friction factor,L is the length of the channel,μis the viscosity of the liquid,Dh the hydrodynamic diameter,and A the cross sectional area.For a laminar fully developed flow the product f*Re=k,a dimensionless constant only depending on the shape of the cross section.The hydraulic resistors we have tested,were realized by anisotropic KOH-etching into a<100>silicon wafer and closing of the channel by anodic bonding of a glass wafer onto the silicon.Fig.1b-d show a side view,a cross section and a top view of the implemented restrictionsrespectively.Figure 1:Hydraulic resistor.a)Symbolic representationb)Side-view of realized restrictions c)Cross section ofealized restrictions d)Top view of a realized restriction.For these triangular channels with a top width of 2w the resistance is given by:The limits of the linear regime have been determined analytically and verified experimentally for liquids[7]. Entrance and exit effects result in a non-linear relation between p12 and.They can be neglected if the channel is long compared to the hydrodynamic entrance length.At low Re the entrance length Lhy increases linearly with Re.For circular channels with a diameter d this is expressed by [6]:2.2 Hydraulic CapacitorsThe hydraulic capacitor physically is an elastic membrane across which a pressure difference can be maintained.It is symbolically represented in fig.2a.The capacitor establishes a relation between the pressure drop across the membrane and the displaced volume.For a linear capacitor the capacitance C is defined by:Where V is the volume of the displaced liquid by bending of the membrane.Because the volume V is created by accumulation of the volume flow,(5)can be rewritten tofind a relation between effort and flow:Figure 2:Hydraulic capacitor a)Symbolic representation b)Cross section of a capacitor realized in glass-silicon-glass technology,showing the deflection of the membrane under influence of a pressure difference.Fig.2b shows a cross section of a capacitor realized in a glass-silicon-glass sandwich.For deflections smaller than the thickness of the membrane there is a linear relation between the applied pressure difference and the membrane deflection.In this case a simple expression for the capacitance can be derived:Where a is the radius of the membrane,and D is the flexural rigidity of the membrane,defined by ,in which E [Pa] is the Young's modulus,ν[-] the Poission's ratio,and h[m] the thickness of the membrane.中文译文：柔韧力液压设备维修和机械加工摘要：液压和气动代理系统工程部门和SC HYDRAMOLD SRL公司的合作实现了一些表演上的液压与气动领域的产品. 文章提出了提供最具代表性的为机械加工和维护液压圆滑设备力量。
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。
液压专业英语(液压专业英语词汇)
液压专业英语词汇流体传动 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液压英文资料流体传动hydraulic power液压技术hydraulics液力技术hydrodynamics气液技术hydropneumatics运行工况operatingconditions额定工况ratedconditions极限工况limitedconditions瞬态工况instantaneous conditions稳态工况steady-state conditions许用工况acceptableconditions连续工况continuousworking conditions实际工况actualconditions效率 efficiency旋转方向directionof rotation公称压力nominalpressure工作压力workingpressure进口压力inletpressure出口压力outletpressure压降 pressure drop；differentialpressure 背压 back pressure启动压力breakoutpressure充油压力chargepressure开启压力crackingpressure峰值压力peakpressure运行压力operatingpressure耐压试验压力proofpressure冲击压力surgepressure静压力staticpressure系统压力systempressure控制压力pilotpressure充气压力pre-chargepressure吸入压力suctionpressure调压偏差overridepressure额定压力ratedpressure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 pneumaticcomponents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 responseHysterics 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（pressurecontrol）流量（速度）控制回路（speedcontrol）方向控制回路（directionalvalve control）安全回路（securitycontrol）定位回路（positioncontrol）同步回路（synchronisecircuit）顺序动作回路（sequeuntcircuit）液压泵（pump）阀（valve）压力控制阀（pressurevalve）、流量控制阀（flow valve）方向控制阀（directionalvalve）液压辅件（accessory）普通阀（commonvalve）插装阀（cartridge valve）叠加阀（superimposedvalve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 pressurecontrol circuit 安全回路 safety circuit差动回路differential circuit调速回路 flowcontrol 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 opencircuit闭式回路 closedcircuit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 portableparticle 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 流量阀冷却器cooler加热器heater温度控制器 thermostat消声器silencer双筒过滤器 duplexfilter过滤器压降 filterpressure drop有效过滤面积 effectivefiltration area公称过滤精度 nominalfiltration rating压溃压力 collapsepressure填料密封 packingseal机械密封 mechanicalseal径向密封 radialseal旋转密封 rotaryseal活塞密封 pistonseal活塞杆密封 rod seal防尘圈密封 wiper seal；scraper组合垫圈 bondedwasher复合密封件 compositeseal弹性密封件 elastomerseal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 electricalpressure 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 frequencyresponse 幅值比amplitude ratio 相位移phase lag传递函数 transferfunction管路flow line硬管rigid tube软管flexible hose工作管路 workingline回油管路 returnline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 hydrauliclock液压卡紧 sticking变量泵variable displacement pump 泵的控制 control ofpump齿轮泵gear pump叶片泵vane pump柱塞泵piston pump轴向柱塞泵 axialpiston pump法兰安装 flangemounting底座安装 footmounting液压马达 hydraulicmotor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 valveSolenoid 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Bulk head 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 低压区一、阀类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。
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。
机械专业外文翻译-挖掘机的机械学和液压学
┊┊┊┊┊┊┊┊┊┊┊┊┊装┊┊┊┊┊订┊┊┊┊┊线┊┊┊┊┊┊┊┊┊┊┊┊┊Multi-Domain Simulation:Mechanics and Hydraulics of an Excavator Abstract It is demonstrated how to model and simulate an excavator with Modelica and Dymola by using Modelica libraries for multi-body and for hydraulic systems. The hydraulic system is controlled by a “load sensing” controller. Usually, models containing3-dimensional mechanical and hydraulic components are difficult to simulate. At hand of the excavator it is shown that Modelica is well suited for such kinds of system simulations.1. IntroductionThe design of a new product requires a number of decisions in the initial phase that severely affect the success of the finished machine. Today, digital simulation is therefore used in early stages to look at different concepts. The view of this paper is that a new excavator is to be designed and several candidates of hydraulic control systems have to be evaluated.Systems that consist of 3-dimensional mechanical and of hydraulic components – like excavators – are difficult to simulate. Usually, two different simulation environments have to be coupled. This is often inconvenient, leads to unnecessary numerical problems and has fragile interfaces. In this article it is demonstrated at hand of the model of an excavator that Modelica is well suited for these types of systems.The 3-dimensional components of the excavator are modeled with the new, free Modelica MultiBody library. This allows especially to use an analytic solution of the kinematic loop at the bucket and to take the masses of the hydraulic cylinders, i.e., the “force elements”, directly into account. The hydraulic part is modeled in a detailed way, utilizing pump, valves and cylinders from HyLib, a hydraulics library for Modelica. For the control part a generic “load sensing” control system is used, modeled by a set of simple equations. This approach gives the required results and keeps the time needed for analyzing the problem on a reasonable level.2. Modeling ChoicesThere are several approaches when simulating a system. Depending on the task it may be necessary to build a very precise model, containing every detail of the system and needing a lot of information, e.g., model parameters. This kind of models is expensive to build up but on the other hand very useful if parameters of a well defined system have to be modified. A typical example is the optimization of parameters of a counterbalance valve in an excavator (Kraft 1996).The other kind of model is needed for a first study of a system. In this case some properties of the pump, cylinders and loads are specified. Required is information about the performance of that system, e.g., the speed of the pistons or the necessary input power at the pump shaft, to make a decision whether this design can be used in principle for the task at hand. This model has therefore to be “cheap”, i.e., it must be possible to build it in a short time without detailed knowledge of particular components.The authors intended to build up a model of the second type, run it and have first results with a minimum amount of time spent. To achieve this goal the modeling language Modelica (Modelica 2002), the Modelica simulation environment Dymola (Dymola 2003), the new Modelica library for 3-dimensional mechanical systems “MultiBody”(Otter et al. 2003) and the Modelica library of hydraulic components HyLib (Beater 2000) was used. The model consists of the 3-dimensional mechanical construction of the excavator, a detailed description of the power hydraulics and a generic “load sensing” controller. This model will be available as a demo in the next version of HyLib.3. Construction of ExcavatorsIn Figure 1 a schematic drawing of a typical excavator under consideration is shown. It consists of a chain track and the hydraulic propel drive which is used to manoeuvre the machine but usually not during a work cycle. On top of that is a carriage where the operator is sitting. It can rotate around a vertical axis with respect to the chain track. It also holds the Diesel engine, the hydraulic pumps and control system. Furthermore, there is a boom, an arm and at the end a bucket which is attached via a planar kinematic loop to the arm. Boom, arm and bucket can be rotated by the appropriate cylinders.┊┊┊┊┊┊┊┊┊┊┊┊┊装┊┊┊┊┊订┊┊┊┊┊线┊┊┊┊┊┊┊┊┊┊┊┊┊Figure 2 shows that the required pressures in the cylinders depend on the position. For the “stretched” situation the pressure in the boom cylinder is 60 % higher than in the retracted position. Not only the position but also the movements have to be taken into account. Figure 3 shows a situation where the arm hangs down. If the carriage does not rotate there is a pulling force required in the cylinder. When rotating –excavators can typically rotate with up to 12 revolutions per minute –the force in the arm cylinder changes its sign and now a pushing force is needed. This change is very significant because now the “active” chamber of the cylinder switches and that must be taken into account by the control system. Both figures demonstrate that a simulation model must take into account the couplings between the four degrees of freedom this excavator has. A simpler model that uses a constant load for each cylinder and the swivel drive leads to erroneous results4. Load Sensing SystemExcavators have typically one Diesel engine, two hydraulic motors and three cylinders. There exist different hydraulic circuits to provide the consumers with the required hydraulic energy. A typical design is a Load Sensing circuit that is energy efficient and user friendly. The idea is to have a flow rate control system for the pump such that it delivers exactly the needed flow rate. As a sensor the pressure drop across an orifice is used. The reference value is the resistance of the orifice. A schematic drawing is shown in figure 4, a good introduction to that topic is given in (anon. 1992).The pump control valve maintains a pressure at the pump port that is typically 15 bar higher than the pressure in the LS line (= Load Sensing line). If the directional valve is closed the pump has therefore a stand-by pressure of 15 bar. If it is open the pump delivers a flow rate that leads to a pressure drop of 15 bar across that directional valve. Note: The directional valve is not used to throttle the pump flow but as a flow meter (pressure drop that is fed back) and as a reference (resistance). The circuit is energy efficient because the pump delivers only the needed flow rate, the throttling losses are small compared to other circuits.If more than one cylinder is used the circuit becomes more complicated, see figure 5. E.g. if the boom requires a pressure of 100 bar and the bucket a pressure of 300 bar the pump pressure must be above 300 bar which would cause an unwanted movement of the boom cylinder. Therefore compensators are used that throttle the oil flow and thus achieve a pressure drop of 15 bar across the particular directional valve. These compensators can be installed upstream or downstream of the directional valves. An additional valve reduces the nominal pressure differential if the maximum pump flow rate or the maximum pressure is reached (see e.g. Nikolaus 1994).5. Model of Mechanical PartIn Figure 6, a Modelica schematic of the mechanical part is shown. The chain track is not modeled, i.e., it is assumed that the chain track does not move. Components “rev1”, ..., “rev4” are the 4 revolute joints to move the parts relative to each other. The icons with the long black line are “virtual”rods that are used to mark specific points on a part, especially the mounting points of the hydraulic cylinders. The light blue spheres (b2, b3, b4, b5) are bodies that have mass and an inertia tensor and are used to model the corresponding properties of the excavator parts.The three components “cyl1f”, “cyl2f”,and “cyl3f” are line force components that describe a force interaction along a line between two attachment points. The small green squares at these components represent 1-dimensional translational connectors from theModelica.Mechanics. Translational library. They are used to define the 1- dimensional force law acting between the two attachment points. Here, the hydraulic cylinders described in the next section are directly attached. The small two spheres in the icons of the “cyl1f,cyl2f, cyl3f” components indicate that optionally two point masses are taken into account that are attached at defined distances from the attachment points along the connecting line. This allows to easily model the essential mass properties (mass and center of mass) of the hydraulic cylinders with only a very small computational overhead.The jointRRR component (see right part of Figure 6) is an assembly element consisting of 3 revolute joints that form together a planar loop when connected to the arm. A picture of this part of an excavator, a zoom in the corresponding Modelica schematic and the animation view is shown in Figure 7. When moving revolute joint “rev4” (= the large red cylinder in the lower part of Figure 7; the small┊┊┊┊┊┊┊┊┊┊┊┊┊装┊┊┊┊┊订┊┊┊┊┊线┊┊┊┊┊┊┊┊┊┊┊┊┊red cylinders characterize the 3 revolute joints of the jointRRR assembly component) the position and orientation of the attachment points of the “left”and “right” revolute joints of the jointRRR component are known. There is a non-linear algebraic loop in the jointRRR component to compute the angles of its three revolute joints given the movement of these attachment points. This non-linear system of equations is solved analytically in the jointRRR object, i.e., in a robust and efficient way. For details see In a first step, the mechanical part of the excavator is simulated without the hydraulic system to test this part separatly. This is performed by attaching translational springs with appropriate spring constants instead of the hydraulic cylinders. After the animation looks fine and the forces and torques in the joints have the expected size, the springs are replaced by the hydraulic system described in the next sections.All components of the new MultiBody library have “built-in” animation definitions, i.e., animation properties are mostly deduced by default from the given definition of the multi-body system. For example, a rod connecting two revolute joints is by default visualized as cylinder where the diameter d is a fraction of the cylinder length L (d = L/40) which is in turn given by the distance of the two revolute joints. A revolute joint is by default visualized by a red cylinder directed along the axis of rotation of the joint. The default animation (with only a few minor adaptations) of the excavator is shown if Figure 8. The light blue spheres characterize the center of mass of bodies. The line force elements that visualize the hydraulic cylinders are defined by two cylinders (yellow and grey color) that are moving in each other. As can be seen, the default animation is useful to get, without extra work from the user side, a rough picture of the model that allows to check the most important properties visually, e.g., whether the center of masses or attachment points are at the expected places.For every component the default animation can be switched off via a Boolean flag. Removing appropriate default animations, such as the “centerof- mass s pheres”, and adding some components that have pure visual information (all visXXX components in the schematic of Figure 6) gives quickly a nicer animation, as is demonstrated in Figure 9. Also CAD data could be utilized for the animation, but this was not available for the examination of this excavator.6. The Hydraulics Library HyLibThe (commercial) Modelica library HyLib (Beater 2000, HyLib 2003) is used to model the pump, metering orifice, load compensator and cylinder of the hydraulic circuit. All these components are standard components for hydraulic circuits and can be obtained from many manufacturers. Models of all of them are contained in HyLib. These mathematical models include both standard textbook models (e. g. Dransfield 1981, Merrit 1967, Viersma 1980) and the most advanced published models that take the behavior of real components into account (Schulz 1979, Will 1968). An example is the general pump model where the output flow is reduced if pressure at the inlet port falls below atmospheric pressure. Numerical properties were also considered when selecting a model (Beater 1999). One point worth mentioning is the fact that all models can be viewed at source code level and are documented by approx. 100 references from easily available literature.After opening the library, the main window is displayed (Figure 10). A double click on the “pumps” icon opens the selection for all components that are needed to originate or end an oil flow (Figure 11). For the problem at hand, a hydraulic flow source with internal leakage and externally commanded flow rate is used. Similarly the needed models for the valves, cylinders and other components are chosen.All components are modeled hierarchically. Starting with a definition of a connector –a port were the oil enters or leaves the component – a template for components with two ports is written. This can be inherited for ideal models, e.g., a laminar resistance or a pressure relief valve. While it usually makes sense to use textual input for these basic models most of the main library models were programmed graphically, i.e., composed from basic library models using the graphical user interface. Figure12 gives an example of graphical programming. All mentioned components were chosen from the library and then graphically connected.7. Library Components in Hydraulics CircuitThe composition diagram in Figure 12 shows the graphically composed hydraulics part of the excavator model. The sub models are chosen from the appropriate libraries, connected and the┊┊┊┊┊┊┊┊┊┊┊┊┊装┊┊┊┊┊订┊┊┊┊┊线┊┊┊┊┊┊┊┊┊┊┊┊┊parameters input. Note that the cylinders and the motor from HyLib can be simply connected to the also shown components of the MultiBody library. The input signals, i.e., the reference signals of the driver of the excavator, are given by tables, specifying the diameter of the metering orifice, i.e. the reference value for the flow rate. From the mechanical part of the excavator only the components are shown in Figure 12 that are directly coupled with hydraulic elements, such as line force elements to which the hydraulic cylinders are attached.8. Model of LS ControlFor this study the following approach is chosen: Model the mechanics of the excavator, the cylinders and to a certain extent the pump and metering valves in detail because only the parameters of the components will be changed, the general structure is fixed. This means that the diameter of the bucket cylinder may be changed but there will be exactly one cylinder working as shown in Figure 1. That is different for the rest of the hydraulic system. In this paper a Load Sensing system, or LS system for short, using one pump is shown but there are other concepts that have to be evaluated during an initial design phase. For instance the use of two pumps, or a separate pump for the swing.The hydraulic control system can be set up using meshed control loops. As there is (almost) no way to implement phase shifting behavior in purely hydraulic control systems the following generic LS system uses only proportional controllers.A detailed model based on actual components would be much bigger and is usually not available at the begin of an initial design phase. It could be built with the components from the hydraulics library but would require a considerable amount of time that is usually not available at the beginning of a project.In Tables 1 and 2, the implementation of the LS control in form of equations is shown. Usually, it is recommended for Modelica models to either use graphical model decomposition or to define the model by equations, but not to mix both descrip- tion forms on the same model level.For the LS system this is different because it has 17 input signals and 5 output signals. One might built one block with 17 inputs and 5 outputs and connect them to the hydraulic circuit. However, in this case it seems more understandable to provide the equations directly on the same level as the hydraulic circuit above and access the input and output signals directly. For example, ”metOri1.port_A.p” used in table 2 is the measured pressure at port_A of the metering orifice metOri1. The calculated values of the LS controller, e.g., the pump flow rate “pump.inPort.signal[1] = ...” is the signal at the filled blue rectangle of the “pump” component, see Figure 12).The strong point of Modelica is that a seamless integration of the 3-dimensional mechanical library, the hydraulics library and the non standard, and therefore in no library available, model of the control system is easily done. The library components can be graphically connected in the object diagram and the text based model can access all needed variables.9. Some Simulation ResultsThe complete model was built using the Modelica modeling and simulation environment Dymola (Dymola 2003), translated, compiled and simulated for 5 s. The simulation time was 17 s using the DASSL integrator with a relative tolerance of 10-6 on a 1.8 GHz notebook, i.e., about 3.4 times slower as real-time. The animation feature in Dymola makes it possible to view the movements in an almost realistic way which helps to explain the results also to non-experts, see Figure 9.Figure 13 gives the reference signals for the three cylinders and the swing, the pump flow rate and pressure. From t = 1.1 s until 1.7 s and from t = 3.6 s until 4.0 s the pump delivers the maximum flow rate. From t = 3.1 s until 3.6 s the maximum allowed pressure is reached. Figure 14 gives the position of the boom and the bucket cylinders and the swing angle. It can be seen that there is no significant change in the piston movement if another movement starts or ends. The control system reduces the couplings between the consumers which are very severe for simple throttling control.Figure 15 shows the operation of the bucket cylinder. The top figure shows the reference trajectory, i. e. the opening of the directional valve. The middle figure shows the conductance of the compensators. With the exception of two spikes it is open from t = 0 s until t = 1 s. This means that in┊┊┊┊┊┊┊┊┊┊┊┊┊装┊┊┊┊┊订┊┊┊┊┊线┊┊┊┊┊┊┊┊┊┊┊┊┊that interval the pump pressure is commanded by that bucket cylinder. After t = 1 s the boom cylinder requires a considerably higher pressure and the bucket compensator therefore increases the resistance (smaller conductance). The bottom figure shows that the flow rate control works fine. Even though there is a severe disturbance (high pump pressure after t = 1 s due to the boom) the commanded flow rate is fed with a small error to the bucket cylinder.10. ConclusionFor the evaluation of different hydraulic circuits a dynamic model of an excavator was built. It consists of a detailed model of the 3 dimensional mechanics of the carriage, including boom, arm and bucket and the standard hydraulic components like pump or cylinder. The control system was not modeled on a component basis but the system was described by a set of nonlinear equations.The system was modeled using the Modelica MultiBody library, the hydraulics library Hylib and a set of application specific equations. With the tool Dymola the system could be build and tested in a short time and it was possible to calculate the required trajectories for evaluation of the control system.The animation feature in Dymola makes it possible to view the movements in an almost realistic way which helps to explain the results also to多畴模拟：挖掘机的机械学和液压学概要：通过使用用于多体和液压系统的Modelica程序库，示范通过Modelica和Dymola如何模拟和仿真挖掘机。
《外文文献翻译-液压系统》
液压系统一个完整的液压系统由五个部分组成，即动力元件、执行元件、控制元件、无件和液压油。
动力元件的作用是将原动机的机械能转换成液体的压力能，指液压系统中的油泵，它向整个液压系统提供动力。
液压泵的结构形式一般有齿轮泵、叶片泵和柱塞泵。
执行元件(如液压缸和液压马达)的作用是将液体的压力能转换为机械能，驱动负载作直线往复运动或回转运动。
控制元件(即各种液压阀)在液压系统中控制和调节液体的压力、流量和方向。
根据控制功能的不同，液压阀可分为村力控制阀、流量控制阀和方向控制阀。
压力控制阀又分为益流阀(安全阀)、减压阀、顺序阀、压力继电器等；流量控制阀包括节流阀、调整阀、分流集流阀等；方向控制阀包括单向阀、液控单向阀、梭阀、换向阀等。
根据控制方式不同，液压阀可分为开关式控制阀、定值控制阀和比例控制阀。
辅助元件包括油箱、滤油器、油管及管接头、密封圈、压力表、油位油温计等。
液压油是液压系统中传递能量的工作介质，有各种矿物油、乳化液和合成型液压油等几大类。
液压的原理它是由两个大小不同的液缸组成的，在液缸里充满水或油。
充水的叫“水压机”；充油的称“油压机”。
两个液缸里各有一个可以滑动的活塞，如果在小活塞上加一定值的压力，根据帕斯卡定律，小活塞将这一压力通过液体的压强传递给大活塞，将大活塞顶上去。
设小活塞的横截面积是S1，加在小活塞上的向下的压力是F1。
于是，小活塞对液体的压强为P=F1/SI, 能够大小不变地被液体向各个方向传递”。
大活塞所受到的压强必然也等于P。
若大活塞的横截面积是S2，压强P在大活塞上所产生的向上的压力F2=PxS2 ，截面积是小活塞横截面积的倍数。
从上式知，在小活塞上加一较小的力，则在大活塞上会得到很大的力，为此用液压机来压制胶合板、榨油、提取重物、锻压钢材等。
液压传动的发展史液压传动和气压传动称为流体传动，是根据17世纪帕斯卡提出的液体静压力传动原理而发展起来的一门新兴技术，1795年英国约瑟夫•布拉曼(Joseph Braman,1749-1814)，在伦敦用水作为工作介质,以水压机的形式将其应用于工业上,诞生了世界上第一台水压机。
机械外文翻译---液压机
中文1829字Hydraulic MachineFrom: The Columbia Encyclopedia, Sixth Edition Date: 2008Hydrulic machine that derives its power from the motion or pressure of water or some other liquid. Hydraulic equipment and technology is something that we are all at least passingly familiar with. If we think about it, we know that the principles of hydraulics are applied to make many common machines work. For example hydraulics are used in agricultural equipment, giant earth moving and mining machines, they are used to steer and stabilize giant ocean liners, help airplanes climb and turn, and make the brakes in our cars work. So hydraulics can provide great force, are obviously very adaptable and used in all kinds of applications, but how do they actually work?What is this hydraulics stuff?Hydraulics is based on a very simple fact of nature - you cannot compress a liquid. You can compress a gas (think about putting more and more air into a tire, the more you put in, the higher the pressure). If you're really strong you can compress a solid mass as well. But no matter how much pressure you apply onto a liquid, it isn't possible to compress it. Now if you put that liquid into a sealed system and push on it at one end, that pressure is transmitted through the liquid to the other end of the system. The pressure is not diminished.. Hydraulics is Old StuffThe basic concept of hydraulics is not new. The Greeks understood about using water to provide lift and force, and the name hydraulics come form the Latin word for water - "HYDRA". In the middle Ages, Leonardo da Vinci formulated the basic principle of hydraulics called continuity and Galileo experimented with hydraulics.Hydraulics were even used during the construction of the Eiffel Tower in Paris in the late 1880's. Hydraulic jacks were used to level the tower and align the metal girders to an accuracy of 1 millimeter。
液压机械英语
液压机械英语在现代工业领域中，液压机械扮演着至关重要的角色。
从大型的建筑设备到精密的机床，液压系统的应用无处不在。
而对于从事液压机械相关工作的人员来说，掌握液压机械英语不仅有助于更好地理解和操作相关设备，也是与国际同行进行交流和学习的必备工具。
首先，让我们来了解一下液压机械中一些常见的基础词汇。
“Hydraulic”这个词就是“液压的”意思，比如“hydraulic system”（液压系统）、“hydraulic cylinder”（液压缸）。
“Pressure”表示“压力”，常见的搭配有“high pressure”（高压）、“low pressure”（低压）。
“Flow”是“流量”，“flow rate”（流量率）就是描述流量大小的术语。
在液压机械的部件方面，“Pump”指的是“泵”，“hydraulic pump”就是液压泵。
“Valve”是“阀”，像“control valve”（控制阀）、“relief valve”（安全阀）在系统中起着重要的调节作用。
“Actuator”是“执行器”，比如“hydraulic actuator”（液压执行器）负责将液压能转化为机械能。
液压机械的工作原理涉及到一系列的英语表述。
例如，“The hydraulic fluid is pressurized by the pump and then flows through the valves and actuators to perform the desired work”（液压油被泵加压，然后通过阀和执行器来完成所需的工作。
）“The pressure in the system is controlled by the relief valve to prevent overpressure”（系统中的压力由安全阀控制，以防止超压。
）在实际应用中，不同类型的液压机械也有各自特定的英语词汇。
例如，在工程机械中，“Excavator”（挖掘机）、“Loader”（装载机）等设备都有复杂的液压系统。
【机械专业文献翻译】液压系统
附录英文原文：HYDRAULIC SYSTEMHydraulic systems are power-transmitting assemblies employing pressurized liquid to transmit energy from an energy-generating source to an energy-use area. All hydraulic systems depend on Pascal’s law, named after Blaise Pascal, who discovered the law. This law states that pressurized fluid within a closed container-such as cylinder or pipe-exerts equal force on all of the surfaces of the container.In actual hydraulic systems, Pascal’s law defines the basis of the results which are obtained from the system. Thus, a pump moves the liquid in the system. The intake of the pumps 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) control of the liquid flow rate, and (3) control of the direction of flow of the liquid.The liquid discharged by the pump in a fluid-power system is directed by valves to a hydraulic motor. A hydraulic motor develops rotary force and motion, using the pressurized liquid as its energy source. Many hydraulic motors are similar to pumps, except that the motor operates in a reverse manner from a pump.Where linear instead of rotary motion is desired, a cylindrical tube fitted with a movable piston, called a hydraulic cylinder, is often used. When the piston is moved by the pressurized fluid, the piston rod imparts a force or moves an object through a desired distance.Restricting the movement of the piston in a hydraulic cylinder, as when the piston carries a load, creates a specific pressure relationship within the cylinder. The surface area of the piston face is said to contain a specific number of square inches. The pressure of the pressurized liquid, multiplied by the piton area, produces an output force, measured in pound, at the end of the piston rod.The speed of movement of the piston rod depends on how fast the pressurized fluid enters the cylinder. Flow into the cylinder can be directed to either end, producing either a pushing or pulling force at the piston rod end. A seal around the rod where it passes through the cylinder end prevents leakage of the liquid.Directional control of the piston depends on which end of cylinder the liquid enters. As pressurized liquid enters one end of the cylinder, liquid must be drained from the other end. The drained liquid is led back to the reservoir. In a pneumatic system using air, the air in the exhausting end of the cylinder is vented to the atmosphere.Directional-control valves, also called two-way, three-way, four-way, etc. , are named in accordance with their basic function. Pressure-control and simple restrictor valves are usually two-way valves. They provide ON or OFF service. A three-way valves may perform severalfunctions, all associated with the three-ports in the valve. For example, the power or pressurized liquid from a pump in a tractor may be sent to the hydraulic system serving the tractor’s front-end loader. Or the three-way valve may send the pressurized liquid to a hydraulic motor driving a feed conveyor while the front-end loader is not being used.Three-way valves may also be used to direct pressurized fluid to a single-acting hydraulic cylinder. As the three-way valve is actuated (operated) it can stop the pressurized flow to the cylinder. Further, the same valve can divert liquid from the cylinder to the reservoir, so the cylinder can retract by gravity or return springs and assume its original position.A four-way valve has four ports or openings. The pressure port directs fluid flow to an area where pressurized liquid is desired. One of the other ports can simultaneously drain liquid from a pressurized area. The dram liquid can be directed to the reservoir.In a fluid-power system, the movement of pressurized fluid resembles the action of electric current in an electrical system. In such a system, electrical energy is continually moving when work is being done. The same is true of a fluid-power system.In a direct-current electrical system, the speed of a device is varied by changing the flow of current to the device. Alternating-current system, use phase shifting to attain similar speed control. Hydraulic system can obtain infinite speed variations by several methods of control, Pneumatic systems, because of the springiness of the gas, have relatively crude speed control.In fluid-power systems, the pump can be designed so the discharge flow of the pressurized liquid can be varied by manipulating the pump mechanism, giving varying speeds of the hydraulic motor or other output device. A restriction un the pump outlet can limit the fluid in a manner similar to that used in a direct-current electrical system. Where desired, hydraulic systems can be designed to use valves which divert flow to different flow channels to give the desired speed control.The compressibility of hydraulic fluid is slight. But, if desired, this slight compressibility can be used to absorb small, erratic machine movements which cause pressure variations in a fluid-power system. Pneumatic systems have this capability inherently because of the springiness of the air or gas used in the system. Hydraulic systems may use one or more accumulators-devices which contain pressurized gas which can accommodate rapid pressure changes in the fluid portion of the system.Gravity, springs and compressed gases provide potential energy I many hydraulic systems. Thus, gravity assist is often used to return a part to its original position without the use of power from the hydraulic system. This type of assistance also simplifies the parts in the hydraulic system.Pumps Mechanical seal Measures.At present the mechanical seal in pumps in a kind of product the application extremely widespread, but and will save the energy along with the product technical level enhancement the request, the mechanical seal application prospect is more widespread. The mechanical seal seal effect directly will affect the entire machine movement, in particular in petroleum chemical industry domain, because will exist flammable, explosive, is easy to volatilize, to be violently poisonous and so on the medium.The mechanical seal appears will divulge, seriously will affect the production normally to carry on, is serious also appears the significant security accident. People when analysis quality breakdown reason, often is familiar with in the mechanical seal own aspect searches the reason, for example: Mechanical seal shaping whether appropriate, choice of material whether correct, thepacking surface compared to presses whether correctly, rubs the vice- choice is whether reasonable and so on. But is short very much in the mechanical seal external condition aspect searches the reason, for example: Pumps for the mechanical seal creation condition whether appropriate, the servosystem disposition is whether appropriate, but these aspects reasons often are count for much.This article author from pumped has analyzed the reasonable measure with the mechanical seal external condition angle which the influence seal effect several kind of factors and should adopt.1 Principle and request that machinery seals off:The mechanical seal is depends on a pair of relative motion link end surface A (fixed, another revolves together with axis) the mutual fitting forms the small axial play plays the seal role, this kind of equipment is called the mechanical seal. The mechanical seal usually by moves the link, the static link, contracts the part and the seal part is composed. Moves the link and the static link end surface composes a pair to rub, moves the link to depend on in the sealed chamber the liquid pressure to cause its shoulder up on the static link end surface, and produces on two links end surfaces suitable compared to presses and maintains an extremely thin liquid membrane to achieve the seal the goal. Contracts the part pressurize, may cause to pump under the operating condition, also maintains the end surface fitting, guaranteed the seal medium nothing more than leaks, and prevented the impurity enters seals the end surface. Seals the part to play the seal to move the link and axis gap B, the static link and the gland gap C role, simultaneously to the vibration which pumps, attacks the cushioning effect. The mechanical seal in the actual movement is not an isolated part, it is with other spare parts which pumps combines the movement together, simultaneously may see through its basic principle, the mechanical seal normal operation has the condition, for instance: Otherwise fleeing measures a pump spindle's being not able to very big, friction subsidiary end face can not form the ratio pressure demanding regularly; The pump spindle that machinery hermetic sealing gets along can not have boundary very big deflection , end face waits a minute otherwise than pressure will be uneven. Besides only when satisfying similar such external condition, fine machinery seals off oneself function, ability reaches ideal hermetic sealing effect.2 Analysis of causes that external condition affects:Pump spindle axial to fleeing is measured big: The hermetic sealing that machinery seals off needs to have certain ratio pressure face to face, such ability plays arrive at hermetic sealing role, be requiring that spring that machinery seals off needs to have certain compression amounts right now, give a propulsive force sealing off end face, rotating makes hermetic sealing produce the pressure sealing off the what be demanded ratio face to face. For ensuring that this one is compared to pressure, the amounts machinery is sealed off requiring that the pump spindle can not have very big fleeing, need to ensure that within 0.5 mm in general. Design but middle in reality, unreasonable because of design, that sometimes, very big fleeing of pump spindle creation measure , seal off to machinery sigmatism is very disadvantageous. This phenomenon sometimes appears in multi-level centrifugal pump, Especially in the process of pump starting, flee amounts are comparatively big.The automation changes the b balancing a set and balancing the axial gap between the ring when balance plate works , changes the difference balancing the pressure checking front and back two flanks thereby , produces one and comes to balance the axial force axial contrary force direction acting force. The inertia effect moving since the rotator flees and transient pump working condition fluctuation, the rotator moving round will not be motionless in some one axial balancelocation.Balance the state fleeing all the time in retinue to move. But the amounts balancing axial to fleeing in checking in regular job only have 0105 ~ 011 mm , satisfy permission axial to fleeing that machinery seals off measuring 015 mm requests, allowable machinery hermetic sealing axial to fleeing balancing axial to fleeing to measure possibility getting it in gear, when stopping machine , working condition great change in pump making rings round expects that.After pumps passes through the long time movement, the friction balancing a set and balancing a ring wears away , gap b enhances subsequently, the amounts sealing off axial to fleeing increase machinery unceasingly. Effect because of axial force, hermetic sealing compacting soft and floury sucking oblique tones in increases by strenuously , hermetic sealing wears the effect aggravating , sealing up completely until hermetic sealing damages , loses face to face away face to face.The machinery spitting out oblique tones is sealed off , is wear away with balancing plate's, rotator component axial to fleeing measures the amounts sealing off axial to fleeing demanding greater than , the force sealing off compacting soft and floury is diminished , cannot reach the effect sealing off a request , making the machinery hermetic sealing on both side of the pump all ultimately losing hermetic sealing.The axial force is prejudiced big: Machinery hermetic sealing can bear the axial force's in the process of usage, if the effect that existence seals off axial the force , to machinery is grave. Since pump axial the aspect cause such as rational and making , assembling , being put into use that dynamic balance organization designs, brings about the axial force be not balanced away sometimes.Machinery hermetic sealing bears a axial force , the seal gland temperature will be partial to height when moving round, to the medium that polypropylene is similar to, before the high temperature be able to be molten down, the pump starts the queen therefore losing hermetic sealing effect very quickly right away , discontinuous gushing sealing off end face then appearing leaves out phenomenon when the pump is motionless.pump spindles deflections are slanting big: That machinery hermetic sealing calls end face hermetic sealing, is that one kind of axis of rotation to contact-type moves hermetic sealing , it is under fluid medium and elasticity component effect , two perpendicularities reach hermetic sealing effect thereby in stick the small side door , relative rapid and intense axle centre line hermetic sealing end face revolution, demands to need to accept a force homogeneously between two hermetic sealing therefore.The machinery spitting out oblique tones is sealed off , is wear away with balancing plate's, rotator component axial to fleeing measures the amounts sealing off axial to fleeing demanding greater than , the force sealing off compacting soft and floury is diminished , cannot reach the effect sealing off a request , making the machinery hermetic sealing on both side of the pump all ultimately losing hermetic sealing.not assisting irrigation system or assists irrigation system to interpose block of wood reasonableness: That assisting that machinery seals off washes system is very important , it can protect effects such as sealing off face , getting to the cooling , lubrication , washing away varia effectively. Design that allocation assists irrigation system, to be unable to reach hermetic sealing effect not rationally sometimes;Have foreign substance sometimes although designing that the personnel has designed auxiliary system, since in washing liquid, rate of flow , pressure washing liquid are insufficient , wash mouth location designing that wait for cause unreasonable , also same being unable to reach hermetic sealing effect.vibration is slanting big: Machinery seals off vibration insisting to lead to big , ultimate losing hermetic sealing effect. That machinery seals off big slanting vibration cause sometimes isnot that machinery seals off self cause but , other pump component and part is to produce the origin vibrating , waits for cause if the pump spindle designs that cause , axle bearing accuracy unreasonable , processing are insufficient , shaft coupling degree difference , radial force of equal rank are big.Cause that the pump vapor erodes: The function is not good , the pump rotation rate is partial to height since device system operation is unreasonable and the pump entrance vapor erodes, that the vapor erodes , the vapor erodes the entry occurrence part in the pump the day afer tomorrow happened , is able to have air bubble in the water, that it may pound machinery on one hand seals off the outside surface soft and floury , makes it's surface damage appear on; That another aspect may make fitting that astiring sound is encircled by also contain air bubble in flow soft and floury film, can not form the stable flow film , brings about the trunk friction that fitting that astiring sound is encircled by face , makes machinery seal damage.Machine work accuracy is insufficient: Machine work accuracy is insufficient , cause has many, the treating accuracy having plenty of machinery sealing self off is insufficient , this aspect cause finds also easy to pay attention to easy to arouse people. But the sometimes is a pump other component treating accuracy lack , this aspect cause, do not pay attention to easy to arouse people. For instance: Cause such as pump spindle , axle sleeve , the pump body , the accuracy lack sealing off enlarging of the cavity body. The hermetic sealing effect that these cause existence seals off to machinery is very disadvantageous.responds to the measure adopting:Remove a pump spindle fleeing to measure big measure:Amounts designing that axial force balance is equipped with , removes axial to fleeing rationally. For satisfying this one request,have two to the multi-level centrifugal pump , the comparatively ideal design plan: One is that balance plate adds axial to stopping push axle bearing , balance the axial force from balance plate , carry out axial on the pump spindle from axial to stopping pushing axle bearing position-limit; Another is that the balance drum adds axial to stopping push axle bearing, axial force balancing away major part from the balance drum, axial surplus force bears from stopping pushing axle bearing , axial to stopping pushing axle bearing carries out axial on the pump spindle at the same time position-limit. Second kinds schemes key is to design the balance drum rationally, makes that be able to balance away the most axial force really. Wait for a product to opening a pump in other single stage pump,within amounts range sealing off range demanded by in machinery designing fleeing adopting a few measure guarantee pump spindles now and then.Remove big axial strenuously prejudiced measure:The organization designing axial dynamic balance rationally, makes that be able to balance away the axial force really sufficiently , being sealed up completely by machinery creates a favorable condition. Must achieve testing detecting and discovering problem and solve a problem before the product , unfinished products leave the factory to importance that fields such as a little electric power plant , petrochemical industry, applies. Some important pumps can design a axial to measuring the force ring on the rotator , monitor at any time to being on the march toward the force size scroll, discover a problem in time solve.Remove big prejudiced pump spindle deflection measure:Existence is in this phenomenon mostly in multi-level centrifugal pump of horizontal type, adopting the following measure time design:(1) cuts down both ends distance between axle bearing. The pump impeller progression is not very more than , under the general pump lift request is comparatively good situation, try one's best to improve every level impeller lift, cuts down progression;(2) increases the pump spindle diameter. During the period of the diameter designing a pump spindle, consider the size transferring power simplely only, do not but want the inertia factors such as load , radial force thinking that machinery seals off ,the axis deflection, starts method and being connected with. Much one point designing that not sufficient cognition arrives at this;(3) improves pump spindle material grade;(4) pump spindles are designed after being completed, the deflection to the pump spindle asks the checkout carrying out the core of school to secretly scheme against. Increases by assisting irrigation system:Under the situation that condition allows, system designing auxiliary irrigation to the full. Wash pressure general requirements overtoping 0107 ~ 011 MPa sealing off cavity pressure, if transportation medium belongs to easy vaporization, respond to 01175 ~ 012 MPa higher than vaporization pressure then. The pressure sealing off a cavity is going to secretly scheme against according to every kind of pump structure during the past factors such as pattern , system pressure.Or when shaft seal accent pressure is very high when pressure uses almost approximation should seal up completely the maximal limit, fever of also may make shaft seal liquid be on the move from the area sealing off a cavity attracting liquid till low pressure, to take away friction. If the irrigation amounts being recommended by administering medicine to bring out the cold be what 1 shows.According to each kind of pump operation condition,deploy the pipeline and accessories rationally. If the chiller , pore plate , filter , valve , rate of flow indicator , piezometer , the temperature wait. Reliability and life-span sealing up completely in fact, depend on the allocation sealing off auxiliary system's to a great extent. Remove the measure that the pump entrance vapor erodes: (1) The vapor eclipse function raising a pump is horizontal , the vapor satisfying the scene device erodes the function request;(2) Scene tester request needs and the pump vapor erodes function level matching;(3) That scene installation and working condition adjustment need to give a pump creates advantageous condition.3.6 Remove the measure that the pump shakes:(1) The product is hit by a pump in designing process , is is going to analyse the source vibrating sufficiently, to eliminate shaking a source. ;(2) Pump product fabrication assembles process middle , directive rules goes and carrying out , eliminates shaking a source strictly according to the standard and operation;(3) Pump , electric motor , assist equipment to be going to guard the pass , eliminate strictly to shake a source during the period of scene installation such as base , scene pipeline,;(4) Guard the pass , eliminate when producing , handling , keeping a scene in repair , adjusting, strictly to shake a source. Execute to the letter design criterion:The design sealing off a product's asks pump product design and machinery to carry out the pertinent home and abroad standard , design that should carry out a standard carefully in the process of the product design,among deep every strip content concrete significance understanding a standard , the process the standard content request implementation is designed to the product.By now, actual import having many standards designing that not understand that , go and carrying out the new standard, not but being to copy the experience designing according to the set of old drawing sheet and old people blind strictly. That this resorts to magic arts to improving our country product engineering level and entering international market is very disadvantageous. Improve the standardizing cognition , be that machinery industry designs that need the problemsolving urgently at present.Pumps when the design with the mechanical seal, not only must consider the mechanical seal itself influence factor, moreover must consider exterior the mechanical seal each kind of influence factor. Must pay attention to following several questions in the practical work:(1) in pumps the product in the design process to have fully to consider pumps other spare parts as well as the scene other equipment to the mechanical seal use effect influence, creates a good external condition for the mechanical seal;(2) increases to the mechanical seal servosystem vital role understanding, provides the consummation as far as possible the mechanical seal servosystem, enhances the seal effect;(3) to importantly pumps the product the mechanical seal, must increase the protective measures, improves the seal quality, reduces the seal quality accident;(4) analyzes the mechanical seal the quality accident reason, must fully consider pumps other spare parts to the mechanical seal movement influence, take the measure unceasingly to enhance the mechanical seal the effect.The bolt pump has because of the person but variable transportation , self attract ability characteristics such as strong , may become worse , being able to transport the liquid containing a solid particle, in sewage treatment factory, be put into use broadly cover in the field of the drug-dip transporting water , wet sludge and flocculant. The bolt pump selects and uses should abide by economy , rational , reliable principle. If doing not think out in the field of the type designing selections, be able to give hereafter sigmatism, to management , be maintained bring about inconvenient , need according to producing reality therefore selecting and using one, now that the rational reliable bolt pump being able to swear to give birth to a child proceeding as planned and without a hitch, reduce mending cost.中文译文：液压系统液压系统是利用液体为介质把能量从动力源传递到消耗位置的动力传递系统。
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。
液压机的设计外文文献翻译
附录A液压机水由高处下降到一个低的高度的时候能产生能量, 可以用来驱动水轮和涡轮等机械.最高和最低水位之间的落差决定了每磅水的能量。
水力可以来自很多自然资源, 例如瀑布和建有大坝的河流等.在没有自然资源的情况下, 可以修建人工水库。
当能量充足的时候可以抽水到水库来储存水能, 当能量不足的时候, 这些储存起来的水可提供能量来驱动涡轮。
工业的液压机械的某些称作储蓄器的机械装置被用来短时间的提供高效的功率.活塞负载重量后装入缸体中, 然后水被缓慢的压入缸体, 活塞和活塞负载的重物给强迫的升到一个高的位置, 当放下他们是,他们强迫缸体中的水迅速的流出, 为机器提供水的压力能。
液压机是由一种液体,特别是水的压力来操纵。
他们在工程领域的广泛应用,例如: 地层移动、矿业、建筑机械、汽车工程、纺织工业、电站、农业机械等。
液压设备水、油压力是常用的动力源, 比如压力机、铆机、起锚机、绞盘等机械. 水压或者静水力压是约瑟夫布拉玛(Joseph Bramah)发现的, 因此优势也称布拉玛压力. 他主要包括连个缸体, 一个是用液体填充, 一个用活塞. 两个缸体用管子连接起来, 也同样用液体填充。
一个缸体是小直径的, 另一个是大直径的. 根据帕斯卡定律, 外界作用在小活塞上压强通过液体毫无损失的传到被迫上升的大活塞的表面。
对于两个活塞来说, 压强(单位面积压力)是相同, 作用在大活塞上向上的压力是作用在小活塞的几倍, 因为大活塞的面积是小活塞的几倍. 比如, 举个例子, 小活塞的面积是2平方英寸, 100lb的压力作用在它上面, 于是作用在具有50平方英寸面积的大活塞上的压力就会有25000lb(100×50/2=2,500). 然而, 让活塞一定时, 小活塞一定的距离也成比例的大于大活塞移动的距离, 这满足能量转换定律。
如果小活塞移动25 英寸,大的活塞就会只移动1英寸。
水压被使用了, 比如, 使三维的物体从一片金属压缩成一个大的物体。
液压系统外文文献翻译、中英文翻译、外文翻译
本科生毕业设计 (论文)外文翻译原文标题液压系统译文标题HYDRAULIC SYSTEMS作者所在系别作者所在专业作者所在班级作者姓名作者学号指导教师姓名指导教师职称完成时间2017 年 4 月15教务处制控制阀控制阀是操作者可访问的阀，用于引导系统内的流体流动以操作机器或其附件。
通过巧妙地使用控制阀，操作员可以调节液压缸的速度和运行。
注意：液压控制应平稳运行，以消除引起机器机械部件快速磨损和破坏的冲击运动。
执行机构（a）旋转叶片液压致动器，（b）线性液压致动器。
通过输入控制信号改变控制阀的位置，允许通过通道流动以操作致动器。
当致动器移动时，其运动沿反馈路径传递，从而抵消控制阀的原始运动。
因此，致动器的输出运动与输入控制运动成比例。
带反馈的旋转风门执行机构线性执行器（RAM）带反馈SPOOL阀门关闭和方向控制阀芯阀直接流到系统的各个部件，并可通过手柄，先导压力信号，电磁螺线管，电动马达和机械凸轮来操作。
用于滑动滑阀方向阀的典型应用是将流体控制到双作用液压缸，其在一个方向上移动时需要在活塞的一侧上的压力下的流体，而另一侧连接到排出管线。
在上述滑阀中，三位置阀芯通过反馈连杆保持在其位置。
在中央位置，所有部件都被锁定。
因此，显而易见的是，当阀芯保持中心时，气缸不能被轻便。
相对于各种端口移动阀芯的位置控制缺陷的方向，如果阀芯向左移动，高压油将通过阀门流到执行器的左侧。
同时，线性执行器的右侧将连接到排气口。
从而将线性致动器向右移动。
一旦致动器已经移动与控制运动成正比的一定量，线轴将自动地通过反馈链路移动到中心。
累积器描述液压蓄能器并解释其目的。
压力蓄能器用于需要储存压力能量以满足需求浪涌的液压系统中，它们还用于吸收液压冲击载荷，并在泵停止时保持压力时补偿小的内部泄漏。
最常见的蓄能器形式包括含有充气和加压柔性气囊的钢壳。
通过特殊阀将气囊预充到所需压力，然后密封以防止气体泄漏。
压力下的液压油进入蓄能器，压缩气囊，直到达到平衡。
机械毕业设计英文外文翻译60常用的液压系统的动力源是泵和蓄能器
附录外文文献原文：The commonly used sources of power in hydraulic systems are pumps and accumulators .Similarly,accumulator connected to atmosphere will dischange oil at atmosphere pressure until it empty. only when connected to a system having resistance to flow can pressure be developed.Three types of pumps find use in fluid-power systems:rotary,reciprocating or piston-type, and 3,centrifugal pumps.Simple hydraulic system may use but one type of pump . The trend is to use pumps with the most satisfactory characteristics for the specific tasks involved . In matching the characteristics of the pump to the requirements of the hydraulic system , it is not unusual to find two types of pumps in series . For example , a centrifugal pump may be to supercharge a reciprocating pump , or a rotary pump may be used to supply pressurized oil for the contronls associated with a reversing variabledisplacement pumps . Most power systems require positive displacement pumps . At high pressure , reciprocating pumps are often preferred to rotary pumps .1、Rotary pumpsThese are built in many differnt designs and extremely popular in modern fluid power system . The most common rotay-pump designs used today are spurgear , internal gear ,generated rotor , sliding vane ,and screew pumps . Ehch type has advantages that make it most suitable for a given application .2、Gear pumpsGear pumps are the simplest type of fixed displacement hydraulic pump available . This type consists of two external gear , generally spur gear , within a closed-fitting housing . One of the gear is driven directly by the pump drive shaft . It ,in turn , then drives the second gear . Some designs utilize helical gears ,but the spur gear design predominates . Gear pumps operate on a very simple principle . As the gear teeth unmesh , the volume at the inlet port A expands , a partial vacuum on the suction side of the pump will be formed . Fluid from an external reservoir or tank is forced by atmospheric pressure into the pump inlet . The continuous action of the fluid being carried from the inlet to the discharge side one of the pump forces the fluid into the system .3、Vane pumpsThe vane pump consists of a housing that is eccentric or offset with respect to the drive shaft axis . In some models this inside surface consists of a cam ring that can be rotated to shift the relationship between rotor are rectangular and extend radially from a center radiusto the outside diameter of the rotor and from end to end . A rectangular vane that is essentially the same size as the slot is inserted in the slot and is free to slide in and out .As the rotor turns , the vanes thrust outward , and the vane tips track the inner surface of the housing , riding on a thin film of fluid . Two port or end plates that engage the end face of the ring provide axial retention .Centrifugal force generally contributes to outward thrust of the vane . As they ride along the eccentric housing surface , the vane move in and out of the rotor slots . The vane divide the area between the rotor and casing into a series of chambers .The sides of each chamber are formed by two adjacent vanes ,the port or end plates , the pump casing and the rotor . These chambers change in change in volume depending on their respective position about the shaft .As each chamber approaches the inlet port , its vanes move outward and its volume expands , causing fluid to flow into the expanded chamber . Fluid is then carried within the chamber around to the dischange port . As the chamber approaches the discharge port , its vanes are pushed inward ,the volume is reduced , and the fluid is forced out the discharge port .Vane pump speed is limited by vane peripheral speed . High peripheral speed will cause cavitation in suction cavity . which results inpump damage and reduced flow .An imbalance of the vanes can cause the oil film between the vane tips and the cam ring to break down , resulting in metal-to-metal contact and subsequent increased wear and slipage . One metheod applied to eliminate high vane thrust loading is a dual-vane construction .4、Piston-type pumpAll piston pumps operate by allowing oil to flow into a pumping cavity as a piston retreats and then forcing the oil out into another chamber as the piston advances . Design differences among pumps lie primarily in the methods of separating inlet from outlet oil .5、In-line piston pumpThe siplest typeof axial piston pump is the swash plate in-line design .The cylinder are connected though piston shoes and a retracting ring , so that the shoes beat anainst an angled swash plate . As the block turns ,the piston shoes follow the swash plate ,causing the piston to reciprocate . The ports are arranged in the valve plate so that the pistons pass the inlet port as they are being pulled out and pass the outlet port as they are being forcing back in .The angle of the swash plate controls the delibery . Where the swash plate is fixed , the pump is of the constant-displacement type . In the variable-displacement , inline piston pump , the swash plate is moumted on a pivoted yoke . As the swash plate angle is increased , thecylinder stroke is increase , resulting in a greater flow . A pressure compensator control can position the yoke automatically to maintain a constant output pressure .6、BENT-axis piston pumpAs the shaft roates , distance between any one piston and the valving surface changes continually . Each piston moves away from the valving surface during one half of the revolution and toward the valving surface during the other half . The inlet chamber is in line as the pistons move away , and the outletr chamber is in line as the pistons move closer , thus drawing liquiring in during one half of the inlet chamber as the pistons are moving away from the pintle . Thereforce , during rotation , pistons draw liquid into the cylinder bores as they pass the inlet side of the pinntle and force that liquid out of the bores as they pass the outlet side of the pintle . The displacement of this pump varies with the offset angle , the maximum angle being 30 degree ,the minimum zero . Fixed displacement models are usually avaiable with 23 degree angle .In the variable displacement construction a yoke with an external control is used to change the angle . With some contronls , the yoke can be moved over center to reverse the direction of flow from the pump .7、Pump/system interactionPressure-compensated variavle delivery pumps do not require arelief valve in the high pressure line . The pressure compensation feature eliminates the need for the relief valve . In nearly all working systems ,however , at least one is used on just-in-case basis . The use of a pressure compensator , while avoiding dependence on a relief valve , brings on its own problems . The actuator -spring-spool arrangement in the compensator is a dynamic , damped-mass-spring arrangement . However , when the system calls for a chang in axhieve their maxmum volume as they reach the inlet port , the maximum volume of fluid will ve moved . If the relationship between housing and rotor is changed such that the chambers achieve their minimum of zero volume as they reach the inlet port , the pump delivery will be reduced to zero .Vane pump speed is limited by vane peripheral speed . High peripheral speed will cause cavitation in suction cavity , which results in pump damage and reduced flow . An imbalance of the vanes can cause the oil film between the cane tips and the cam ring to break down , resulting in metal-to-metal contact and subsequent increased wear and slipage . One method applied to eliminate high vane thrust loading is a dual-vane construction . In the dual-vane construction , tow independent vanes are located in each totor slot chmbered edges along the sides and top of each vane from a channel that essentially balances the hydraulic pressure on the top and bottom of each pair of vanes .Centrifugal force cause the vane to follow the contour of thecam-shaped ring .There is just sufficient seal between the vanes and ring without destroying the thin oil film .外文文献中文翻译：常用的液压系统的动力源是泵和蓄能器。
机械外文翻译—液压机Hydraulic Machine
Hydraulic MachineFrom: The Columbia Encyclopedia, Sixth Edition Date: 2008Hydraulic machine that derives its power from the motion or pressure of water or some other liquid. Hydraulic equipment and technology is something that we are all at least passingly familiar with. If we think about it, we know that the principles of hydraulics are applied to make many common machines work. For example hydraulics are used in agricultural equipment, giant earth moving and mining machines, they are used to steer and stabilize giant ocean liners, help airplanes climb and turn, and make the brakes in our cars work. So hydraulics can provide great force, are obviously very adaptable and used in all kinds of applications, but how do they actually work?What is this hydraulics stuff?Hydraulics is based on a very simple fact of nature - you cannot compress a liquid. You can compress a gas (think about putting more and more air into a tire, the more you put in, the higher the pressure). If you're really strong you can compress a solid mass as well. But no matter how much pressure you apply onto a liquid, it isn't possible to compress it. Now if you put that liquid into a sealed system and push on it at one end, that pressure is transmitted through the liquid to the other end of the system. The pressure is not diminished.. Hydraulics is Old StuffThe basic concept of hydraulics is not new. The Greeks understood about using water to provide lift and force, and the name hydraulics come form the Latin word for water - "HYDRA". In the middle Ages, Leonardo da Vinci formulated the basic principle of hydraulics called continuity and Galileo experimented with hydraulics. Hydraulics were even used during the construction of the Eiffel Tower in Paris in the late 1880's. Hydraulic jacks were used to level the tower and align the metal girders toan accuracy of 1 millimeter。
外文翻译--液压动力的介绍-精品
附录附录1英文原文Introduction to Fluid Power1.1 WHAT IS FLUID POWER?Fluid power is the technology that deals with the generation, control, and trans-mission of power-using pressurized fluids. It can be said that fluid power is the muscle that moves industry. This is because fluid power is used to push, pull, regulate, or drive virtually all the machines of modern industry. For example, fluid power steers and brakes automobiles, launches spacecraft, moves earth, harvests crops, mines coal, drives machine tools, controls airplanes, processes food, and even drills teeth. In fact, it is almost impossible to find a manufactured product that hasn’t been “fluid-powered” in some way at some stage of its production or distribution.Since a fluid can be either a liquid or a gas, fluid power is actually the general term used for hydraulics and pneumatics. Hydraulic systems use liquids such as petroleum oils, water, synthetic oils, and even molten metals. The first hydraulic fluid to be used was water because it is readily available. However, water has many deficiencies. It freezes readily, is a relatively poor lubricant, and tends to rust metal components. Hydraulic oils are far superior and hence are widely used in lieu of water. Pneumatic systems use air as the gas medium because air is very abundant and can be readily exhausted into the atmosphere after completing its assigned task.It should be realized that there are actually two different types of fluid systems: fluid transport and fluid power.Fluid transport systems have as their sole objective the delivery of a fluid from one location to another to accomplish some useful purpose. Examples include pumping stations for pumping water to homes, Cross-country gas lines, and systems where chemical processing takes place as various fluids are brought together.Fluid power systems are designed specifically to perform work. The work is accomplished by a pressurized fluid bearing directly on an operating fluid cylinder or fluid motor. A fluid cylinder produces a force, whereas a fluid motor produces a torque.Fluid cylinders and motors thus provide the muscle to do the desired work. Of course, control components are also needed to ensure that the work is done smoothly, accurately, efficiently, and safely.Liquids provide a very rigid medium for transmitting power and thus can provide huge forces to move loads with utmost accuracy and precision. On the other hand, pneumatic systems exhibit spongy characteristics due to the compressibility of air. However, pneumatic systems are less expensive to build and operate. In addition, provisions can be made to control the operation of the pneumatic actuators that drive the loads.Fluid power equipment ranges in size from huge hydraulic presses to miniature fluid logic components used to build reliable control systems.How versatile is fluid power? In terms of brute power, a feather touch by an operator can control hundreds of horsepower and transmit it to any location where a hose or pipe can go. In terms of precision such as applications in the machine tool industry, tolerances of one ten-thousandth of an inch can be achieved and repeated over and over again. Fluid power is not merely a powerful muscle; it is a controlled, flexible muscle that provides power smoothly, efficiently, safely, and precisely to accomplish useful work.Figure 1-1 shows a pneumatically controlled dextrous hand designed to study machine dexterity and human manipulation in applications such as robotics and tactile sensing. Servo-controlled pneumatic actuators give the hand human-like grasping and manipulating capability. Key operating characteristics include high speed in performing manipulation tasks, strength to easily grasp hand-sized objects that have varying densities, and force grasping control. The hand possesses three fingers and an opposing thumb, each with four degrees of freedom. Each joint is positioned by two pneumatic actuators (located in an actuator pack with the controlling servo valve) driving a high-strength tendon. Performance and configuration constraints concerning the weight, size, geometry, cleanliness, and availability of individual actuators led to the choice of pneumatic actuation.1.2 HISTORY OF FLUID POWERFluid power is probably as old as civilization itself. Ancient historical accounts show that water was used for centuries to produce power by means of water wheels, and air was used to turn windmills and propel ships. However, these early uses of fluid powerrequired the movement of huge quantities of fluid because of the relatively low pressures provided by nature.Fluid power technology actually began in 1650 with the discovery of Pascal’s law: Pressure is transmitted undiminished in a confined body of fluid.Pascal found that when he rammed a cork down into a jug completely full of wine, the bottom of the jug broke and fell out. Pascal’s law indicated that the pres sures were equal at the top and bottom of the jug. However, the jug has a small opening area at the top and a large area at the bottom. Thus, the bottom absorbs a greater force due to its larger area.In 1750, Bernoulli developed his law of conservation of energy for a fluid flowing in a pipeline. Pascal’s law and Bernoulli’s law operate at the very heart of all fluid power applications and are used for analysis purposes. However, it was not until the Industrial Revolution of 1850 in Great Britain that these laws would actually be applied to industry. Up to this time, electrical energy had not been developed to power the machines of industry. Instead, it was fluid power that, by 1870, was being used to drive hydraulic equipment such as cranes, presses, winches, extruding machines, hydraulic jacks, shearing machines, and riveting machines. In these systems, steam engines drove hydraulic water pumps, which delivered water at moderate pressures through pipes to industrial plants for powering the various machines. These early hydraulic systems had a number of deficiencies such as sealing problems because the designs had evolved more as an art than a science.Then, late in the nineteenth century, electricity emerged as a dominant technology. This resulted in a shift of development effort away from fluid power. Electrical power was soon found to be superior to hydraulics for transmitting power over great distances. There was very little development in fluid power technology during the last 10 yr of the nineteenth century.The modern era of fluid power is considered to have begun in 1906 when a hydraulic system was developed to replace electrical systems for elevating and con-trolling guns on the battleship USS Virginia. For this application, the hydraulic system developed used oil instead of water. This change in hydraulic fluid and the subsequent solution of sealing problems were significant milestones in the rebirth of fluid power.In 1926 the United States developed the first unitized, packaged hydraulic system consisting of a pump, controls, and actuator. The military requirements leading up toWorld War II kept fluid power applications and developments going at a good pace. The naval industry had used fluid power for cargo handling, winches, propeller pitch control, submarine control systems, operation of shipboard aircraft elevators, and drive systems for radar and sonar.During and after World War lithe aviation and aerospace industry provided the impetus for many advances in fluid power technology. Examples include Hydraulic-actuated landing gears, cargo doors, gun drives, and flight control devices such as rudders, ailerons, and elevons for aircraft. Figure 1-2 shows the space shuttle Columbia, powered by fluid thrust forces, soaring from its launch pad. The space shuttle takes off like a rocket and the winged orbiter then maneuvers around Earth like a spaceship. After completing its mission it lands on a runway like an airplane. Unlike earlier manned space craft, which were good for only one flight, the shuttle orbiter and rocket boosters can be used again and again. Only the external tank is expended on each launch. Figure 1-3 provides a cutaway view of the shuttle vehicle, identifying its main components, many of which are hydraulically actuated.The expanding economy that followed World War II led to the present situation where there are virtually a limitless number of fluid power applications. Today fluid power is used extensively in practically every branch of industry. Some typical applications are in automobiles, tractors, airplanes, missiles, boats, and machine tools. In the automobile alone, fluid power is utilized in hydraulic brakes, automotive trans-missions, power steering, power brakes, air conditioning, lubrication, water coolant, and gasoline pumping systems. The innovative use of modern technology such as electro-hydraulic closed-loop systems, microprocessors, and improved materials for component construction will continue to advance the performance of fluid power systems.Relative to automotive applications, Fig. 1-4 is a diagram showing the Bendix Hydro-Boost Power Brake System. The basic system consists of an open center spool valve and hydraulic cylinder assembled in a single unit (see Fig. 1-5). Operating pressure is supplied by the power steering pump. Hydro-Boost provides a power assist to operate a dual master-cylinder braking system. Normally mounted on the engine compartment fire wall, it is desig ned to provide specific “brake-feel” characteristics throughout a wide range of pedal forces and travel. A spring accumulator stores energy for reverse stops. From one to three stops are available depending on the magnitude and duration of the brake application. This system was developed by Bendix Corporation as an answer to crowded engine compartments and replaces the large vacuum units.1.3 ADVANTAGES OF FLUID POWERThere are 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.The secret of fluid power’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 capacity of fluid systems is limited only by the physical strength of the material (such as steel) used for each component.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 system can readily start, stop, speed up or slow down, and position forces that provide any desired horsepower with tolerances as precise as one ten-thousandth of an inch. Figure 1-6 shows a fluid power system that allows an aircraft pilot to raise and lower his landing gear. When the pilot moves a small control valve in one direction, oil under pressure flows to one end of the cylinder to lower the landing gear. To retract the landing gear, the pilot moves the valve lever in the opposite direction, allowing oil to flow into the other end of the cylinder.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. Figure 1-7 shows an application where a rugged, powerful drive is required for handling huge logs. In this case, a turntable, which is driven by a hydraulic motor, can carry a 20,000-lb load at a loft radius (a torque of 200,000 ft ib) under rough operating conditions.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. Figure 1-8 depicts an application in oceanography that involves the exploration and de velopment of the ocean’s resources for the benefit of humankind. In this instance, it is important for the operator to apply a desired constant grabbing force through the use of the grappling hooks.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. Figure 1-9 shows a power steering control designed for off-highway vehicles. The steering unit (shown attached to the steering wheel column in Fig. 1-9) consists of a manually operated directional control valve and meter in a single body. See Fig. 1-10 for a cutaway of this steering unit. 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 operator fatigue. The compact design and versatility of the control system allow the unit to control many large and high-powered systems with a high degree of reliability. The steering unit shown in Fig. 1-10 contains a check valve that converts the unit to a hand-operated pump for emergency power-off steering.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.Drawbacks of Fluid PowerIn 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 eliminate completely. Hydraulic lines can burst, possibly resulting in injuries to people due to high-speed oil jets and flying pieces of metal, if proper design is not implemented. Prolonged exposure to loud noise such as that emanating from pumps, can result in loss of hearing. Also, most hydraulic oils can cause fires if an oil leak occurs in an area of hot equipment. Therefore, each application must be studied thoroughly to determine the best overall design. It is hoped that this book will not only assist the reader in developing the ability to make these types of systemselection decisions but also present in a straightforward way the techniques for designing, analyzing, and troubleshooting basic fluid power systems.1.4 APPLICATIONS OF FLUID POWERAlthough a number of cases of fluid power have already been presented in this chapter, the following additional applications should give the reader a broader view of the widespread use of fluid power in today’s world.1. fluid power drives high-wire overhead tram. Most overhead trams require a haulage or tow cable to travel up or down steep inclines. However, the 22-passenger, 12,000-lb hydraulically powered and controlled Sky-tram shown in Fig. 1-11 is unique. It is self-propelled and travels on a stationary cable. Because the tram moves instead of the cable, the operator can stop, start, and reverse any one car completely independently of any other car in the tram system. Integral to the design of the Sky-tram drive is a pump (driven by a standard eight-cylinder gasoline engine), which supplies pressurized fluid to four hydraulic motors. Each motor drives two friction drive wheels.Eight drive wheels on top of the cables support and propel the tram car. On steep inclines, high driving torque is required for ascent and high braking torque for descent. Dual compensation of the four hydraulic motors provides efficient proportioning of available horsepower to meet the variable torque demands.2. fluid power is applied to harvesting corn. The world’s de pendence on the United States for food has resulted in a great demand for agricultural equipment development. Fluid power is being applied to solve many of the problems dealing with the harvesting of food crops. Figure 1-12 shows a hydraulically driven elevator conveyor system, which is used to send harvested, husked ears of corn to a wagon trailer. Mounted directly to the chain-drive conveyor, a hydraulic motor delivers full-torque rotary power from start-up to full rpm.3．Hydraulics power brush drives. Figure 1-13 shows a fluid power—driven brush drive used for cleaning roads, floors, etc., in various industrial locations. Mounted directly at the hub of the front and side sweep-scrub brushes, compact hydraulic motors place power right where it’s needed. They eliminate bulky mechanical linkages for efficient, lightweight machine design. The result is continuous, rugged industrial cleaning action at the flip of a simple valve.4. fluid power positions and holds parts for welding. In Fig. 1-14, we see an example of a welding operation in which a farm equipment manufacturer applied hydraulics for positioning and holding parts while welding is done. It is a typical example of how fluid power can be used in manufacturing and production operations to reduce costs and increase production. This particular application required a sequencing system for fast, positive holding. This was accomplished by placing a restrictor (sequence valve) on the flow of oil in the line leading to the second of the two cylinders (rams), as illustrated in Fig. 1-15. The first cylinder extends to the end of its stroke. Oil pressure then builds up, overcoming the restrictor setting, and the second cylinder extends to complete the “hold” cycle. This unique welding ap plication of hydraulics was initiated to increase productivity by making more parts per hour. In addition, the use of hydraulics reduced scrap rates and operator fatigue as well as increasing productivity from 5 pieces per shift to more than 20—a 400 % increase.5. Fluid power performs bridge maintenance. A municipality had used fluid power for years as a means for removing stress from structural members of bridges, making repairs, and replacing beams. As many as four or five bulky, low-pressure hand pumps and jacking ram setups were used to remove stress from beams needing replacement. Labor costs were high, and no accurate methods existed for recording pressures. An excessive downtime problem dictated that a new system be designed for the job. A modern fluid power system was designed that located several 100-ton rams on the bridge structure, as illustrated in Fig. 1-16. One portable pump was used to actuate all of the rams by the use of a special manifold. This made it easy to remove stress from members needing repair or replacement. This new fluid power system cut the setup time and labor costs for each repair job to one-third that required with the hand pump and jacking ram setups previously used6. Fluid power is the muscle in industrial lift trucks. Figure 1-17 shows an industrial hydraulic lift truck with a 5000-lb capacity. The hydraulic system includes dual-action tilt cylinders and a hoist cylinder. Tilting action is smooth and sure for better load stability and easier load placement. A lowering valve in the hoist cylinder controls the speed of descent even if the hydraulic circuit is broken. Hydrostatic power steering is available as an optional feature.7. Fluid power drives front-end loaders. Figure 1-18 shows a front-end loader fillinga dump truck with soil scooped up by a .large hydraulic-powered bucket. Excellent load control is made possible with a specially designed flow control valve. The result is loweffort and precise control; this keeps the operator working on the job longer and more efficiently. Thus, reduced operator fatigue results in increased production8. Hydraulics power robotic dextrous arm. Figure 1-19 shows a hydraulically powered robotic arm that has the strength and dexterity to torque down bolts with its fingers and yet can gingerly pick up an eggshell. This robotic arm is adept at using human tools such as hammers, electric drills, and tweezers and can even bat a baseball. The arm has a hand with a thumb and two fingers, as well as a wrist, elbow, and shoulder. It has ten degrees of freedom, including a three-degree-of-freedom end effector (hand) designed to handle human tools and other objects with human-like dexterity. The servo control system is capable of accepting computer or human operator control inputs. The system can be designed for carrying out hazardous applications in the subsea, utilities, or nuclear environments, and it is also available in a range of sizes from human proportions to 6 ft long.1.5 COMPONENTS OF A FLUID POWER SYSTEMHydraulic SystemThere are six basic components required in a hydraulic system:1. A tank (reservoir) to hold the liquid, which is usually hydraulic oil.2. A pump to force the liquid through the system.3. An electric motor or other power source to drive the pump.4. Valves to control liquid direction, pressure, and flow rate.5. An actuator to convert the energy of the liquid into mechanical force or torque to do useful work. Actuators can either be cylinders to provide linear motion, as shown in Fig. 1-20, or motors (hydraulic) to provide rotary motion, as shown in Fig. 1-21.6. Piping, which carries the liquid from one location to another.Of course, the sophistication and complexity of hydraulic systems will vary depending on the specific applications. This is also true of the individual components that comprise the hydraulic system. As an example, refer to Fig. 1-22, which shows two different-sized, complete, hydraulic power units designed for two uniquely different applications. Each unit is a complete, packaged power system containing its own electric motor, pump, shaft coupling, reservoir and miscellaneous piping, pressure gages, valves, and other components as required for proper operation. These hydraulic components and systems are studied in detail in subsequent chapters.Pneumatic SystemPneumatic systems have components that are similar to those used in hydraulic sys-tems. Essentially the following six basic components are required for pneumatic systems:1. An air tank to store a given volume of compressed air2. A compressor to compress the air that comes directly from the atmosphere3. An electric motor or other prime mover to drive the compressor4. Valves to control air direction, pressure, and flow rate5. Actuators, which are similar in operation to hydraulic actuators6. Piping to carry the pressurized air from one location to anotherFigure 1-23 shows a compact, self-contained pneumatic power unit complete with tank, compressor, electric motor, and miscellaneous components such as valves, piping, and pressure gages.It should be noted in pneumatic systems that after the pressurized air is spent driving actuators, it is then exhausted back into the atmosphere. On the other hand, in hydraulic systems the spent oil drains back to the reservoir and is repeatedly reused after being repressurized by the pump as needed by the system.1.6 CLOSED-LOOP VERSUS OPEN-LOOP SYSTEMSFluid power systems can be either the closed-loop or open-loop type. The following describes these two types of fluid power systems.Closed-Loop SystemA closed-loop system is one that uses feedback. This means that the state of the output from the system is automatically sampled and compared (fed back) to the input or command signal by means of a device called a feedback transducer. If there is a difference between the command and feedback signals, action is taken to correct the system output until it matches the requirement imposed on the system. Closed-loop systems are frequently called servo systems, and the valves used to direct fluid to the actuators are typically called servo valves.Open-Loop SystemAn open-loop system does not use feedback. The output performance of the system therefore depends solely on the characteristics of the individual components and how they interact in the circuit. Most hydraulic circuits are of the open-loop type, which are generally not so complex or so precise as closed-loop systems. This is because any errors such as slippage (oil leakage past seals, the magnitude of which depends on system pressure and temperature) are not compensated for in open-loop systems. For example,the viscosity of a hydraulic fluid decreases (fluid becomes thinner) as its temperature rises. This increases oil leakage past seals inside pumps, which, in turn, causes the speed of an actuator, such as a hydraulic motor, to drop. In a closed-loop system, a feedback transducer (for example, a tachometer, which generates a signal proportional to the speed at which it is rotated) would sense this speed reduction and feed a proportional signal back to the command signal. The difference between the two signals is used to control a servo valve, which would then increase the fluid flow rate to the hydraulic motor until its speed is at the required level.1.7 TYPES OF FLUID POWER CONTROL SYSTEMSFluid power systems are also classified by the type of control system utilized. There are three basic types of fluid power control systems: electrical, fluid logic, and pro-grammable logic. The following is a brief description of each of these three control systems.Electrical Control SystemThis type of fluid power control system is characterized by the fact that the fluid power system interacts with a variety of electrical components for control purposes. For example, electrical components such as pressure switches, limit switches, and relays can be used to operate electrical solenoids to control the operation of valves that direct fluid to the hydraulic actuators. An electrical solenoid control system permits the design of a very versatile fluid power circuit. Automatic machines such as those used in the machine-tool industry rely principally on electrical components to control the hydraulic muscles for doing the required work. The aircraft and mobile equipment industries have also found that fluid power and electricity work very well together, especially where remote control is needed. By merely pressing a simple push-button switch, an operator can control a very complex machine to perform hundreds of machinery operations to manufacture a complete product. An electrically controlled fluid power system can be either of the open-loop or closed-loop type, depending on the precision required.Fluid Logic Control SystemThis type is characterized by the fact that the fluid power system interacts with fluid logic devices instead of with electrical devices for control purposes. Two such fluid logic systems are called “moving-part logic (MPL)” and “fluidics,” which perform a wide variety of sensory and control functions. Fluid logic devices switch a fluid, usually air, from one outlet of the device to another outlet. Hence an output of a fluid logic device is either ON or OFF as it rapidly switches from one state to the other by the application of a control signal.。
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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 divided into the hydraulic valve control switch valve, control valve and set the value of the ratio control valve. Auxiliary components, including fuel tanks, oil filters, tubing and pipe joints, seals, pressure gauge, oil level, such as 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 liquid a sliding piston, if the increase in the small piston on the pressure of a certain value, according to Pascal's law, small piston to the pressure of the pressure through the liquid passed to the large piston, piston top will go a long way to 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 a smaller force, the piston will be in great force, for which the hydraulic machine used to suppress plywood, oil, extract heavy objects, such as forging 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 the world's first hydraulic press. Media work in 1905 will be replaced by oil-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 energy 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 than Europe 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 water projects with flood control the dam gates and devices, bed lifts installations, bridges and other manipulation of institutions; speed turbine power plant installations, nuclear power plants, etc.; ship deck crane (winch), the bow doors, bulkhead valves, such as the stern thruster ; special antenna technology giant with control devices, measurement buoys, movements such as rotating stage; military-industrial control devices used in artillery, ship anti-rolling devices, aircraft simulation, aircraft retractable landing gear and rudder control devices and other 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。