外文翻译--变速液压装置-精品
液压装置-外文资料翻译
液压装置压力之源——泵和压缩机从原理上讲，适于泵送流体的大多数泵都可以泵送空气或气体，尽管大多数油泵几乎不作为空气压缩机来用，而某些压缩机未作调整则不可以输送非压缩性流体。
考虑原则。
对一台可以传送足够大压力以供实际使用的液压泵能力的主要要求是：a控制流体泄漏的措施。
要么用特殊密封要么紧缩加工间隙。
b要真正均匀而非脉冲式输送。
c在运行中不存在空穴现象，因为作为实际用途的流体都是非压缩性的。
d机械平衡达到足够程度以使泵能尽可能快地旋转，目的是已定输出流量时减小泵的体积。
e由于泵内有内压力，要有充分的措施，以最大限度减小工作零件、泵壳等的变形的影响。
f间隙量要小，以便在起动期间很快动作，对含气流体，泵可像压缩机那样，把空气通过输送管线排出，而不让它潴留在泵中。
g配置适当的进油阀或配流装置，以使泵能产生良好真空吸油作用，或者另一种情况下即飞机上高空飞行操作的液压装置或较高粘度作为液压油时更应采取这些措施，应该注意的是入口阀或油门开启的时间，这几乎和油口尺寸一样重要。
一台良好压缩机的主要要求是：a）与机械间隙相适应的尽可能小的间隙容积。
这是因为在间隙容积中被压缩的任何气体都将再次膨胀而不是被排放掉。
相反，不仅将影响泵的输出，而且影响可能产生的最高压力。
b）除低压泵外，要有两个或更多的压缩阶段。
使阶段间有尽可能多的中间冷却。
由于气体是进行绝热压缩的而不是等温过程压缩的，因此，首先希望减少功和输出量的损失。
其次，由于间隙容积的原因，要减少总体上的输出损失。
c）泵中空气预压缩压力升高到输送管线中压力。
尽管标准往复泵因具有自动阀或受压弹簧阀能保证这点，但某些旋转式压缩机则必须专门配上气阀来配流，以便获得预压缩，而另一些泵则全然不可能做到。
泵内无预压力，一旦输气阀口打开，管线中气体膨胀而回到泵内，泵内全部流体不得不再次被压缩。
具有预压缩装置的旋转压缩机不可能输送油流。
d）缸体气冷或水冷措施，使得压缩机中气体温度尽可能保持等温状态，而被输送的气体体积相应增加。
外文翻译---液压机械装置振动问题处理
原文Solving Vibration Problems In HydraulicMachineryAbstractIn the current paper, various cases of vibration problems detected in hydraulic machinery are presented.These cases were found during several years of vibration monitoring.the problems have been classified depending on their origin.For all of them,a systematic approach is given indicating the symptoms,the exciatation provoking them,the possibilities of amplification due to resonance and the remedies that have been applied.IntroductionVibration problems are common in hydraulic machinery.Solving them helps to increase the machine life and to reduce maintenance costs.Many cases have been found and solved during last years of monitoring (Egusquiza 1998 and Egusquiza et.2000).Some of them have been due to design or mounting problems and others due to damage in machine elements.The cases presented here correspond to large machine with vertical shaft and rigid coupling.The problems found have been classified in the following types:Type 1: Excessive excitations of hydraulic originType 2: Hrust bearing problemsType 3: Unbalance and misalignmentType 4: Electromagnetic problemA methodology to solve these types of vibration problems is proposed in the paper.The steps to follow are indicated in Fig,1.Once the abnormal high vibration amplitudes have been detected through scheduled monitoring or machine malfunctioning.Vibration analysis has to be proformde to identify the origin of the exciation provoking them.Various techniques are availabledepending on the type of excitation under consideration,whether it is hydraulic,mechanic orEletromagnetion.The resulting high vibration levels may also be due to some type of resonace in the hydraulic system or in the mechanical compoents.Therefore, this possibility must be checed before a correct diagnostic can be made.Finally, remedies to the probiem are proposed and their success is confirmed comparing the vibrations after the modification with theprevious ones.Type 1: Excessive Hydraulic Excitation.Typical vibrations of hydraulic origin are generated by rotor-stator interaction (RSI) and by cacitation.RSI is due to the interference between the runner blades and guide vanes.It can generate pressure pulsations of high amplitude in hydraulic machines.As a result,cracks in runners and excessive vibrationlevels in machine and piping can be produced.RSI identification is normally easy with spectral analysis of vibration.The problem is to know if the vibration is high due to the excitation itself,to a high hydraulic system is high due to the excitation resonse or to a runner/motor resonance.The vibration will be at a frequency f b given by:F b=n*f*z b=With maximum amplitude at the lowest diametrical mode excited k according to the following equation(tanaka 1990):n*z v+-k=m*z bAnother typical phenomenon that can generate vibrations is cavitation.Cavitation can take several forms and can result in vibrations,losses of performance and erosion. The most common type of cavitation is part load suige. Its negative effects are usually mitigated by means of air entrapment in draft tube. On the other hand, inlet cacitation provoking erosion of runner blades is also a concern due to its destructive effects.Here there are some examples for both types of hydraulic excitations. High vibrations in thecasingof a multistage pumpA multistage pump had high vibration levels in the casing during operation. The generated vibrations produced the burst of pipes and other elements. Initially, it was thought that the vibrations were due to wear or damage(malfunctioning). As a result, the pump was completely dismantled and repaird. Surprisingly, the vibration did not disappear.A general scheme of the pump is given in fig,2.During pumping the machine delivers a flow rate of 2.8 m3/s to a head of 935 m.Other machine characteristics are listed in Table 1.To understand the cause of the high vibertion levels some experimental measurements and a theoretical analysis were carried out.From the spectral analysis it was found that the vibration amplitude occurred at 150 Hz which is f b(see Fig,5).therefore,the vibration has a fluid dynamic origin and its high amplitude might be due to several reasons such as high RSI excitation due to design,mounting,damage,or resonance. In this case,the RSI analysis gives a pressure pulsation around the impeller with a diametrical mode k=-2 rotating in the opposite direction of the impeller st f b.First of all, the hydraulic system response of the return channel was calculated using a transfer matrix method. No frequencies around 150Hz were found. Furthermore, the analysis of the measurements(phase and amplitude variation)at different roating speeds neither showed resonance around the excitation frequency.Modal analysis from the impacts done with an insteumented hammer was carried out to check the possibility of mechuanical resonance in the casing or impeller.For the casing,no resonance was found at around the frequency of 150 Hz as it can be seen in Fig,3. Atheoretical analysis with FEM gave similar results.The frequency response functions obtained from impacts in the impeller areindicated in Fig,4. They show the presence of a mode at 472 Hz. This mode was susceptible of excitation because it corresponded to diametrical mode 2. Estimating a reduction factor of 0.45 to 0.5in order to consider the added mass and the casing boundary,the actual natural frequency would lie between 212 and 236 Hz. So, there was a low probability of resonance. In fact, no high vibration levels were present at the bearings.Finally, analyzing the phasing of the pressure pulsation and vibration in the casing, the diagnosis was that the high vibrations were caused by the interaction of the pressure pulsation inside the machine.In this case the solution was to change the relative position between impellers. After that, vibration was reduced considerably as it is shown in Fig,5 where RSI vibrations before and after repair are compare.Vibration on runner of a pump-turbine.In this case, the machine was a single stage reversible pump-turbine. Its main characteristics are listed in table 2. this pump suffered form cracks in the impeller blades.For the Z b and Z v combinations, the diametrical mode k=-2 occurs at 2*f b(=140 Hz) and should be the most important excitation. This is exactly what can be seen in the vibration spectrum shown in Fig, 6.After analyzing the system response, checking the natural frequencies of runner and rotor, it was found that a rotor naturalfrequency was was close to the excitation frequency. As the system could not be changed physically, the solution of the problem was devised as modifying the runner lacation where cracks appeared to reduce stresses on blades.Partial load surge and inlet cavitation erosion on blades of a francis turbine.This unie was a vertical shaft francis turbine operating up to a maximum output power of 65 MW. The total nominal flow rate and the net head were 57.5m3/s and 122.5m. the rest of characteristics are listed in Table 3.In this case two problems had been detected. The first one was excessivevibration levels in the draft tube. The second one was advanced erosion on the suction side of the blades.In Fig, 7 overall vibration levels measured for the entire range of power outputs indicate that amplitudes are more important during operation at partial loads. In the Fig,8, spectral analysis of shaft displacement using proximity probes can be observed at 20 and 55MW. When operating at 20MW, a frequency peak at 0.27*f f predominates but disappears at 55 MW. This analysis indicated the presence of a hub rope in the draft tube at partial loads.Spectral analysis is enough to detect partial load surge but it is not useful for other types of cavitation. This is the case of erosive cavitation is especially destructive.Another technique to be used is to demodulate high frequency vibrations. In Fig,9, the spectra of the envelope in the frequency band form 30k to 40k Hz are plotted. Again, at 20 MW the presence of the part load surge is well detected in the top of the Fig.So,the possible remedies such as optimization of air injection fins are currently being analyzed. Meanwhile, it has been recommended to avoid operation at loads below 35 MW.For the detection of erosive cavitation high frequency vibrations also had to be measured (Escaler et al.2002). Amplitude demodulation of high frequency bands, shown in the bottom of Fig,9, indicated the presence of a pulsating cavity in the runner at f v at 55MW. The maximum amplitude of this peak was found at 60 MW, thus indicating the maximum cavitation aggressiveness. Therefore, the solution consisted in limiting the time of operation around 60MW whenever possible. A refurbishing of the runner (new hydrodynamic design) is expected to be the solution in this case.Type 2: thrust bearing problemsAnother type of problem sometimes found in vertical shaft machines is rubbing in thrust bearing which can provoke its rapid destruction. In guidebearings,radial loading is usually low and they are not so affected.Machines are prone to have friction during start-up and coast-down if only hydrodynamic lubrication exists. During operating, vibration can be generated especially when load on the pads is not evenly distributed. A possibility for detection is to install a vertical proximity probe or an absolute vibration sensor located next to the bearing pads in axial direction. The use of joint-time frequency analysis is very adequate to idenfuty such frictions that can occur in very short periods of time.At steady operation, spectral analysis helps to identify potential problems by looking at the pad passing frequency. For instance, in Fig,10,this frequency disappears from the vibration signature after repairing the bearing. Although detection is easy,to quantify the level of the damage is diffcult from the vibration signature and the peak amplitude. A proximity probe is convenient as well as oil analysis to complete the diagnostic.In Fig, 11, another example is shown. The predominant peak at passing frequency indicates a damage in the bearing. Its amplitude decreased significantly after repair.Type 3: unbalance and misalignmentUnbalance and especially misalignment are common problem in vertical shaft machine with rigid coupling.Unbalbance detection and solution is not diffcult except when hydraulic or magnetic forces or a resonance zre involved in it. It is important to identify the type of unbalance before doing the repair. Vibration measurements at different loads and with the machine idle are necessary. In Fig, 12 the spectrum of a machine with unbalance produced by a blockage in runner channels can be observed. In this case, it was observed that the f f. another situation which is potentially dangerous is when a small part of the runner breaks off due to fatigue. Here, the change in unbalance is mot large and damage is diffcult to detect.Other cases difficilt to solve are when there is resonance with a rotornatural frequency. In Fig,13，a case with misalignment can be observed. The first rotor lateral frequency is almost coincident with a times the rotating frequency. Here the machine has some degree of misalignment which is enhanced by the resonance. In the top of the Fig,14,the 2*f f peak has an RMS amplitude around 1.2 mm/s when the machine operates at full load. Meanwhile,in the bottom of the same Fig,the same peak shows an amplitude of about 0.4 mm/s at 40% of the load.As the natural frequency varies depending on the machine load and other paraments, the vibration amplitudes change continuosly what makes diffcult to have an accurate ternd analysis in the monitoring. In this case the solution is not straightforward.Rotordynamic analysis based in FEM can be used to model the motor,to identify the type of resonance and to find a remedy. Inaccuracies arise when simulating an installed machine due to the lack of exact geometrical data, bearing stiffness,and so on. Therefore simulation must be checked with some experimental data. Thisis rather complex because the natural frequency are diffcult to excite in a large machine. Joint time frequency analysis can be used during transients or after impacting tha machine when in operation in order to identify them,as shown in Fig,14.Type 4: electromagnetic problemsThis type of problems are basically due to eccentricity or damage in generator.In Fig,15,spectra of a machine before(front) and after excessive vibration in the generatoe are shown. The predominant vibration occurs at two times the electrical line frequency,in our case 100Hz. After repair of the stator, where some damage was found,the vibration amplitude at 100Hz was considerably reduced.翻译部分液压机械装置振动问题处理摘要：在本篇论文中，我们将讨论液压机械装置不同情况下的各种振动问题。
液压系统外文文献翻译、中英文翻译、外文文献翻译
附录Hydraulic SystemHydraulic presser drive and air pressure drive hydraulic fluid as the transmission is made according to the 17th century, Pascal's principle of hydrostatic pressure to drive the development of an emerging technology, the United Kingdom in 1795 •Barman Joseph (Joseph Barman, 1749-1814), in London water as a medium to form hydraulic press used in industry, the birth of the world's first hydraulic press. Media work in 1905 will be replaced by oil-water and further improved.After the World War I (1914-1918) ,because of the extensive application of hydraulic transmission, 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. Vickers) the invention of the pressure balanced vane pump, hydraulic components for the modern industrial or hydraulic transmission of the gradual establishment of the foundation. The early 20th century G • Constantia scofluctuations of the energy carried out by passing theoretical and practical research; in 1910 on the hydraulic trans- mission (hydraulic coupling, hydraulic torque converter, etc.) contributions, so that these two areas of 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 fornearly 20 years later. Before and after in 1955, 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 industrial use of plastics processing machinery, the pressure of machinery, machine tools, etc.; operating machinery engineering machinery, construction machinery, agricultural machinery, automobiles, etc.; iron and steel industry metallurgical machinery, lifting equipment, such as roller adjustment device; civil water projects with flood control and dam gate devices, bed lifts installations, bridges and other manipulation of institutions; speed turbine power plant installations, nuclear power plants, etc.; ship from the deck heavy machinery (winch), the bow doors, bulkhead valve, stern thruster, etc.; special antenna technology giant with control devices, 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.A complete hydraulic system consists of five parts, namely, power components, the implementation of components, control components, auxiliary components and hydraulic oil.The role of dynamic components of the original motive fluid into mechanical energy to the pressure that the hydraulic system of pumps, it is to power the entire hydraulic system. The structure of the form of hydra- ulic pump gears are generally pump, vane pump and piston pump.Implementation of components (such as hydraulic cylinders and hydraulic motors) which isthe pressure of the liquid can be converted to mechanical energy to drive the load for a straight line reciprocating movement or rotational movement.Control components (that is, the various hydraulic valves) in the hydraulic system to control and regulate the pressure of liquid, flow rate and direction. According to the different control functions, hydraulic pressure control valve can be divided into valves, flow control valves and directional control valve. Pressure control valves are divided into benefits flow valve (safety valve), pressure relief valve, sequence valve, pressure relays, etc.; flow control valves including throttle, adjusting the valves, flow diversion valve sets, etc.; directional control valve includes a one-way valve , one-way fluid control valve, shuttle valve, valve and so on. Under the control of different ways, can be divided into the hydraulic valve control switch valve, control valve and set the value of the ratio control valve.Auxiliary components, including fuel tanks, oil filters, tubing and pipe joints, seals, pressure gauge, oil level, such as oil dollars.Hydraulic oil in the hydraulic system is the work of the energy transfer medium, there are a variety of mineral oil, emulsion oil hydraulic molding Hop categories.The role of the hydraulic system is to help humanity work. Mainly by the implementation of components to rotate or pressure into a reciprocating motion.Hydraulic system and hydraulic power control signal is composed of two parts, the signal control of some parts of the hydraulic power used to drive the control valve movement.Part of the hydraulic power means that the circuit diagram used to show the differentfunctions of the interrelationship between components. Containing the source of hydraulic pump, hydraulic motor and auxiliary components; hydraulic control part contains a variety of control valves, used to control the flow of oil, pressure and direction; operative or hydraulic cylinder with hydraulic motors, according to the actual requirements of their choice.In the analysis and design of the actual task, the general block diagram shows the actual operation of equipment. Hollow arrow indicates the signal flow, while the solid arrows that energy flow.Basic hydraulic circuit of the action sequence - Control components (two four-way valve) and the spring to reset for the implementation of components (double-acting hydraulic cylinder), as well as the extending and retracting the relief valve opened and closed. For the implementation of components and control components, presentations are based on the corresponding circuit diagram symbols, it also introduced ready made circuit diagram symbols.Working principle of the system, you can turn on all circuits to code. If the first implementation of components numbered 0, the control components associated with the identifier is 1. Out with the implementation of components corresponding to the identifier for the even components, then retracting and implementation of components corresponding to the identifier for the odd components. Hydraulic circuit carried out not only to deal with numbers, but also to deal with the actual device ID, in order to detect system failures.DIN ISO1219-2 standard definition of the number of component composition, which includes the following four parts: device ID, circuit ID, component ID and component ID.The entire system if only one device, device number may be omitted.Practice, another way is to code all of the hydraulic system components for numbers at this time, components and component code should be consistent with the list of numbers. This method is particularly applicable to complex hydraulic control system, each control loop are the corresponding number with the systemWith mechanical transmission, electrical transmission compared to the hydraulic drive has the following advantages:1. a variety of hydraulic components can easily and flexibly to layout.2. light weight, small size, small inertia, fast response.3. to facilitate manipulation of control, enabling a wide range of stepless speed regulation (speed range of 2000:1).4. to achieve overload protection automatically.5. the general use of mineral oil as a working medium, the relative motion can be self-lubricating surface, long service life;6. it is easy to achieve linear motion .7. it is easy to achieve the automation of machines, when the joint control of the use of electro-hydraulic, not only can achieve a higher degree of process automation, and remote control can be achieved.The shortcomings of the hydraulic system:1. as a result of the resistance to fluid flow and leakage of the larger, so less efficient. If not handled properly, leakage is not only contaminated sites, but also may cause fire and explosion.2. vulnerable performance as a result of the impact of temperature change, it would be inappropriate in the high or low temperature conditions.3. the manufacture of precision hydraulic components require a higher, more expensive and hence the price.4. due to the leakage of liquid medium and the compressibility and can not be strictly the transmission ratio.5. hydraulic transmission is not easy to find out the reasons for failure; the use and maintenance requirements for a higher level of technology.In the hydraulic system and its system, the sealing device to prevent leakage of the work of media within and outside the dust and the intrusion of foreign bodies. Seals played the role of components, namely seals. Medium will result in leakage of waste, pollution and environmental machinery and even give rise to malfunctioning machinery and equipment for personal accident. Leakage within the hydraulic system will cause a sharp drop in volumetric efficiency, amounting to less than the required pressure, can not even work. Micro-invasive system of dust particles, can cause or exacerbate friction hydraulic component wear, and further lead to leakage.Therefore, seals and sealing device is an important hydraulic equipment components. The reliability of its work and life, is a measure of the hydraulic system an important indicator of good or bad. In addition to the closed space, are the use of seals, so that two adjacent coupling surface of the gap between the need to control the liquid can be sealed following the smallest gap. In the contact seal, pressed into self-seal-style and self-styled self-tight seal (ie, sealed lips) two.The three hydraulic system diseases1. as a result of heat transmission medium (hydraulic oil) in the flow velocity in various parts of the existence of different, resulting in the existence of a liquid within the internal friction of liquids and pipelines at the same time there is friction between the inner wall, which are a result of hydraulic the reasons for the oil temperature. Temperature will lead to increased internal and external leakage, reducing its mechanical efficiency. At the same time as a result of high temperature, hydraulic oil expansion will occur, resulting in increased com- pression, so that action can not be very good control of transmission. Solution: heat is the inherent characteristics of the hydraulic system, not only to minimize eradication. Use a good quality hydraulic oil, hydraulic piping arrangement should be avoided as far as possible the emergence of bend, the use of high-quality pipe and fittings, hydraulic valves, etc.2. the vibration of the vibration of the hydraulic system is also one of its malaise. As a result of hydraulic oil in the pipeline flow of high-speed impact and the control valve to open the closure of the impact of the process are the reasons for the vibration system. Strong vibration control action will cause the system to error, the system will also be some of the more sophisticated equipment error, resulting in system failures. Solutions: hydraulic pipe should be fixed to avoid sharp bends. To avoid frequent changes in flow direction, can not avoid damping measures should be doing a good job. The entire hydraulic system should have a good damping measures, while avoiding the external local oscillator on the system.3. the leakage of the hydraulic system leak into inside and outside the leakage. Leakagerefers to the process with the leak occurred in the system, such as hydraulic piston-cylinder on both sides of the leakage, the control valve spool and valve body, such as between the leakage. Although no internal leakage of hydra- ulic fluid loss, but due to leakage, the control of the established movements may be affected until the cause system failures. Outside means the occurrence of leakage in the system and the leakage between the external environment. Direct leakage of hydraulic oil into the environment, in addition to the system will affect the working environment, not enough pressure will cause the system to trigger a fault. Leakage into the environment of the hydraulic oil was also the danger of fire. Solution: the use of better quality seals to improve the machining accuracy of equipment.Another: the hydraulic system for the three diseases, it was summed up: "fever, with a father拉稀" (This is the summary of the northeast people). Hydraulic system for the lifts, excavators, pumping station, dynamic, crane, and so on large-scale industry, construction, factories, enterprises, as well as elevators, lifting platforms, Deng Axle industry and so on.Hydraulic components will be high-performance, high-quality, high reliability, the system sets the direction of development; to the low power, low noise, vibration, without leakage, as well as pollution control, water-based media applications to adapt to environmental requirements, such as the direction of development; the development of highly integrated high power density, intelligence, macaronis and micro-light mini-hydraulic components; active use of new techniques, new materials and electronics, sensing and other high-tech.---- Hydraulic coupling to high-speed high-power and integrated development of hydraulic transmission equipment, development of water hydraulic coupling medium speedand the field of automotive applications to develop hydraulic reducer, improve product reliability and working hours MTBF; hydraulic torque converter to the development of high-power products, parts and components to improve the manufacturing process technology to improve reliability, promote computer-aided technology, the development of hydraulic torque converter and power shift transmission technology supporting the use of ; Clutch fluid viscosity should increase the quality of products, the formation of bulk to the high-power and high-speed direction.Pneumatic Industry:---- Products to small size, light weight, low power consumption, integrated portfolio of development, the implementation of the various types of components, compact structure, high positioning accuracy of the direction of development; pneumatic components and electronic technology, to the intelligent direction of development; component performance to high-speed, high-frequency, high-response, high-life, high temp- erature, high voltage direction, commonly used oil-free lubrication, application of new technology, new technology and new materials.1. Used high-pressure hydraulic components and the pressure of continuous work to reach 40Mpa, the maximum pressure to achieve instant 48Mpa;2. Diversification of regulation and control;3. To further improve the regulation performance, increase the efficiency of the power train;4. Development and mechanical, hydraulic, power transmission of the composite portfolio adjustment gear;5. Development of energy saving, energy efficient system function;6. To further reduce the noise;7. Application of Hydraulic Cartridge Valves thread technology, compact structure, to reduce the oil spill.液压系统液压传动和气压传动称为流体传动，是根据17世纪帕斯卡提出的液体静压力传动原理而发展起来的一门新兴技术，1795年英国约瑟夫•布拉曼(Joseph Braman,1749-1814)，在伦敦用水作为工作介质，以水压机的形式将其应用于工业上，诞生了世界上第一台水压机。
中英文文献翻译-液压制动系统
附录AHydraulic Brake SystemsWhen you step on the brake pedal,you expect the vehicle to stop.The brake pedal operates a hydraulic that is used for two reasons.First,fluid under pressure can be carried to all parts of the vehicle by small hoses or metal lines without taking up a lot of room of causing routing problems.Second,the hydraulic fluid offers a great mechanical advantage-little foot pressure is required on the pedal,but a great deal of pressure is generated at the wheels.The brake pedal is linked to a piston in the brake master cylinder containing a small piston and a fluid reservoir.Modern master cylinders are actually two separate cylinders.Such a system is called a dual circuit,because the front cylinder is connected to the front brakes and the rear cylinder to the rear brakes.(Some vehicles are connected diagonally).The two cylinders are actually separated,allowing for emergency stopping power should one part of the system fail.The entire hydraulic system from the master cylinder to the wheels is full of hydraulic brake fluid.When the brake pedal is depressed,the piston in the master cylinder are forced to move,exerting tremendous force on the fluid in the lines.The fluid has nowhere to go,and forces the wheel cylinder pistons(drum brakes) orcaliper pistons(disc brakes) to exert pressure on the brake shoes or pads.The friction between the brake shoe and wheel drum or the brake pad and rotor (disc) slows the vehiche and eventually stops it.Also attached to the brake pedal si a switch that lights the brake lights as the pedal is depressed.The lights stay on until the brake pedal is released and returns to its normal position.Each wheel cylinder in a drum brake system contains two pistons,one at either end,which push outward in opposite directions.In disc brake systems,the wheel cylinders are part of the caliper (there can be as many as four or as few as one ).Whether disc or drum type,all pistons use some type of rubber seal to prevent leakage around thepiston,and a rubber dust boot seals the outer of the wheel cylinders against dirt and moisture.When the brake pedal is released,a spring pushes the master cylinder pistons back to their normal positions.Check valves in the master cylinder piston allow fluid to flow toward the wheel cylinders or calipers as the piston returns.Then as the brake shoe return springs pull the brake shoes back to the released position,excess fluid returns to the master cylinder through compensating ports,which have been uncovered as the pistons move back.Any fluid that has leaked from the system will also be replaced through the compensating ports.All dual circuit brake systems use a switch to activate a light,warning of brake failure.The switch si located in a valve mounted near the master cylinder.A piston in the valve reveives pressure on each end from the front and rear brake circuits.When the pressures are balanced,the piston remains stationary,but when one circuit has a leak,greater pressure during the application of the brakes will force the piston to one side or the other,closing the switch and activating the warning light.The light can also be activated by the ignition switch during engine starting or by the parking brake.Front disc,rear drum brake systems also have a metering valve to prevent the front disc brakes from engaging before the rear brakes have contacted the drums.This ensures that the front brakes will not normally be used alone to stop the vehicle.A proportioning valve is also used to limit pressure to the rear brakes to prevent rear wheel lock-up during hard braking.Brake shoes and pads are constructed in a similar.The pad or shoe is composed of a metal backing plate and a priction lining.The lining is either bonded(glued) to the metal,or riveted.Generally,riveted linings provide superior performance,but good quality bonded linings are perfectly adequate.Friction materials will vary between manufacturers and type of pad and the material compound may be referred to as asbestos,organic,semi-metallic,metallic.The difference between these compounds lies in the types and percentages of friction materials used,material binders and performance modifiers.Generally speaking,organic and non-metallic asbestos compound brakes are quiet,easy on rotors and provide good feel.But this comes at the expense of high temperature operation,so they may not be your best choice for heavy duty use or mountiandriving.In most cases,these linings will wear somewhat faster than metallic compound pads,so you will usually replace them more often.But,when using these pads,rotors tend to last longer.Semi-metallic or metallic compound brake linings will vary in performance based on the metallic contents of the compound.Again,generally speaking,the higher the metallic content,the better the friction material will resist heat.This makes them more appropriate for heavy duty applications,but at the expense of braking performance before the pad reaches operating temperature.The first few applications on a cold morning may not give strong braking.Also,metallics and semi-metallics are more likely to squeal,In most cases,metallic compounds last longer than non-metallic pads,but they tend to cause more wear on the rotors.If you use metallic pads,expect to replace the rotors more often.When deciding what type of brake lining is right for you,keep in mind that today’s modern cars have brake materials which are matched to the expected vehicle’s performance capabilities.Changing the material from OEM specification could adversely addect brake feel or responsiveness.Before changing the brake materials,talk to your deaker or parts supplier to help decide what is most appropriate for your application. Remenber that use applications such as towing,stop and go driving,driving down mountain roads,and racing may require a change to a higher performance material.Some more exotic materials are also used in brake linings,among which are Kevlar and carbon compounds.These materials have the capability of extremely good performance for towing,mountain driving or racing.Wear characteristics can be similar to either applications tend to wear like metallic linings,while many of the streetapplications aremore like the non-metallics.附录B液压制动系统当踩下制动踏板，您希望该车辆停下。
自动五速手动变速箱- EASYTRONIC 3.0外文文献翻译、中英文翻译
附录1：外文翻译自动五速手动变速箱- EASYTRONIC 3.0。
The new Opel/Vauxhall公司在2014年秋季推出了自动化五速手动变速箱(MTA) Easytronic 3.0。
该变速器使用电动液压离合器和位移控制，其主要部件主来自手动变速箱(F17-5)。
这个新的变速器新增了停止/启动功能，而他的控制系统是根据安全标准ISO 26262设计的。
DIPL.-ING。
THOMAS ZEMMRICH是德国Adam Opel公司变速器自动化MT系统组长和技术专家。
持续战略2014年秋季，欧宝/沃克斯豪尔公司引进了新一代自动化手动变速器MTA(手动变速器) Easytronic 3.0。
这延续了公司自2001年开始战略，通过这种低成本的变速器有效代替小型车辆的常规自动变速器。
由于传统变速器在传动过程中有扭矩中断会使车辆在驾驶时舒适度不佳。
因此，他们设计了与传统变速箱相比操作操作更简便，燃油经济性更好的，并且带有运动驾驶风格的自动化变速器。
这篇文章介绍了欧宝新推出的MTA 的设计和性能特点。
变速器的设计这款新推出的变速器是在Opel公司五速手动变速箱(F17-5)的基础上开发的，它的扭矩容量为190Nm。
这款变速器用在中小型汽油发动机手动档车型上的排量高达1.4L，用在材油机手动挡车型上的排量为1.3L。
虽然拥有高达200Nm转矩容量的6速变速箱越来越受到欢迎，但是考虑到成本，目前五速版的变速箱任是小型汽车的首选。
这款变速器采用拨叉和同步器进行换档，所选的齿轮组传动比范围为5.53，这对于一个五速变速箱来说是一个相当大的传动比范围。
由于较大的传动比范围，使得一档工作时不需要输入较大的转矩，使驾驶舒适性能得到提高，且在五档工作时不需要发动机输入较高的转速就可以获得较高的驾驶速度，还能够降低噪音，提高燃油经济性。
后者是实现自动手动变速器而不损失任何性能，因为加速度可以通过快速自动降档来实现。
液压系统外文文献翻译中英文
外文文献翻译(含：英文原文及中文译文)英文原文Hydraulic systemW Arnold1 IntroductionThe hydraulic station is called a hydraulic pump station and is an independent hydraulic device. It is step by step to supply oil. And control the direction of hydraulic oil flow, pressure and flow, suitable for the host and hydraulic equipment can be separated on the various hydraulic machinery.After the purchase, the user only needs to connect the hydraulic station and the actuator (hydraulic or oil motor) on the mainframe with different tubings. The hydraulic machine can realize various specified actions and working cycles.The hydraulic station is a combination of manifolds, pump units or valve assemblies, electrical boxes, and tank electrical boxes. Each part function is:The pump unit is equipped with a motor and an oil pump, which is the power source of the hydraulic station and can convert mechanical energy into hydraulic oil pressure energy.V alve combination - its plate valve is mounted on the vertical plate, and the rear plate is connected with the same function as the manifold.Oil manifolds - assembled from hydraulic valves and channel bodies. It regulates hydraulic oil pressure, direction and flow.Box--a semi-closed container for plate welding. It is also equipped with an oil screen, an air filter, etc., which is used for cooling and filtering of oil and oil.Electrical box - divided into two types: one is to set the external lead terminal board; one is equipped with a full set of control appliances.The working principle of the hydraulic station: The motor drives the oil pump to rotate, then the pump sucks oil from the oil tank and supplies oil, converts the mechanical energy into hydraulic pressure energy, and the hydraulic oil passes through the manifold (or valve assembly) to adjust the direction, pressure and flow and then passes through the external tube. The way to the hydraulic cylinder or oil motor in the hydraulic machinery, so as to control the direction of the hydraulic motor, the strength of the speed and speed, to promote all kinds of hydraulic machinery to do work.(1) Development history of hydraulic pressureThe development history of hydraulics (including hydraulic power, the same below), pneumatics, and seals industry in China can be roughly divided into three stages, namely: the starting stage in the early 1950s to the early 60s; and the professional in the 60s and 70s. The growth stage of the production system; the 80-90's is a stage of rapid development. Among them, the hydraulic industry began in the early 1950s with thedevelopment of hydraulic machines such as Grinding Machines, broaching machines, and profiling lathes, which were produced by the machine tool industry. The hydraulic components were produced by the hydraulic workshop in the machine tool factory, and were produced for self use. After entering the 1960s, the application of hydraulic technology was gradually promoted from the machine tool to the agricultural machinery and engineering machinery. The original hydraulic workshop attached to the main engine plant was independent and became a professional manufacturer of hydraulic components. In the late 1960s and early 1970s, with the continuous development of mechanization of production, particularly in the provision of highly efficient and automated equipment for the second automobile manufacturing plant, the hydraulic component manufacturing industry witnessed rapid development. The batch of small and medium-sized enterprises also began to become specialized manufacturers of hydraulic parts. In 1968, the annual output of hydraulic components in China was close to 200,000 pieces. In 1973, in the fields of machine tools, agricultural machinery, construction machinery and other industries, the professional factory for the production of hydraulic parts has grown to over 100, and its annual output exceeds 1 million pieces. Such an independent hydraulic component manufacturing industry has taken shape. At this time, the hydraulic product has evolved from the original imitation Su product intoa combination of imported technology and self-designed products. The pressure has been developed towards medium and high pressures, and electro-hydraulic servo valves and systems have been developed. The application of hydraulics has been further expanded. The pneumatic industry started a few years later than hydraulics, and it was only in 1967 that it began to establish a professional pneumatic components factory. Pneumatic components began to be manufactured and sold as commodities. Its sealing industry including rubber seals, flexible graphite seals, and mechanical seals started from the production of common O-rings, oil seals, and other extruded rubber seals and asbestos seal products in the early 1950s. In the early 1960s, it began to develop and produce flexible products. Graphite seals and mechanical seals and other products. In the 1970s, a batch of batches of professional production plants began to be established one after another in the systems of the former Ministry of Combustion, the Ministry of Agriculture, and the Ministry of Agricultural Machinery, formally forming the industry, which laid the foundation for the development of the seal industry.In the 1980s, under the guidance of the national policy of reform and opening up, with the continuous development of the machinery industry, the contradiction between the basic components lags behind the host computer has become increasingly prominent and caused the attention of all relevant departments. To this end, the former Ministry of Machinesestablished the General Infrastructure Industry Bureau in 1982, and unified the original pneumatic, hydraulic, and seal specialties that were scattered in the industries of machine tools, agricultural machinery, and construction machinery, etc. The management of a piece of office, so that the industry in the planning, investment, the introduction of technology and scientific research and development and other aspects of the basic parts of the bureau's guidance and support. This has entered a period of rapid development, it has introduced more than 60 foreign advanced technology, of which more than 40 hydraulic, pneumatic 7, after digestion and absorption and technological transformation, are now mass production, and has become the industry's leading products . In recent years, the industry has intensified its technological transformation. From 1991 to 1998, the total investment of national, local, and corporate self-raised funds totaled about 2 billion yuan, of which more than 1.6 billion were hydraulic. After continuous technological transformation and technological breakthroughs, the technical level of a group of major enterprises has been further improved, and technological equipment has also been greatly improved, laying a good foundation for forming a high starting point, specialization, and mass production. In recent years, under the guidance of the principle of common development of multiple ownership systems in the country, various small and medium-sized enterprises with different ownership have rapidly emerged and haveshown great vitality. With the further opening up of the country, foreign-funded enterprises have developed rapidly, which plays an important role in raising industry standards and expanding exports. So far China has established joint ventures with famous manufacturers in the United States, Germany, Japan and other countries or directly established piston pumps/motors, planetary speed reducers, hydraulic control valves, steering gears, hydraulic systems, hydrostatic transmissions, and hydraulic components. The company has more than 50 manufacturing enterprises such as castings, pneumatic control valves, cylinders, gas processing triplets, rubber seals, and mechanical seals, and has attracted more than 200 million U.S. dollars in foreign capital.(2) Current statusBasic profileAfter more than 40 years of hard work, China's hydraulics, pneumatics and seals industry has formed a complete industrial system with a certain level of production capacity and technical level. According to the statistics of the third n ational industrial census in 1995, China’s state-owned, privately-owned, cooperative, village-run, individual, and “funded enterprises” have annual sales income of more than 1 million yuan in hydraulic, pneumatic, and seal industrial townships and above. There are a total of more than 1,300 companies, including about 700 hydraulics, and about 300 pneumatic and sealing parts. According to thestatistics of the international industry in 1996, the total output value of the hydraulic industry in China was about 2.448 billion yuan, accounting for the 6th in the world; the total output value of the pneumatic industry was about 419 million yuan, accounting for the world’s10 people.2. Current supply and demand profileWith the introduction of technology, independent development and technological transformation, the technical level of the first batch of high-pressure plunger pumps, vane pumps, gear pumps, general hydraulic valves, oil cylinders, oil-free pneumatic components and various types of seals has become remarkable. Improve, and can be stable mass production, provide guarantees for all types of host to improve product quality. In addition, certain achievements have also been made in the aspects of CAD, pollution control, and proportional servo technology for hydraulic pneumatic components and systems, and have been used for production. So far, the hydraulic, pneumatic and seal products have a total of about 3,000 varieties and more than 23,000 specifications. Among them, there are about 1,200 types of hydraulic pressure, more than 10,000 specifications (including 60 types of hydrodynamic products, 500 specifications); about 1350 types of pneumatic, more than 8,000 specifications; there are also 350 types of rubber seals, more than 5000 The specifications are now basically able to adapt to the general needs ofvarious types of mainframe products. The matching rate for major equipment sets can reach more than 60%, and a small amount of exports has started.In 1998, the domestic production of hydraulic components was 4.8 million pieces, with sales of about 2.8 billion yuan (of which mechanical systems accounted for 70%); output of pneumatic components was 3.6 million pieces, and sales were about 550 million yuan (including mechanical systems accounting for about 60%) The production of seals is about 800 million pieces, and the sales volume is about 1 billion yuan (including about 50% of mechanical systems). According to the statistics of the annual report of the China Hydraulic and Pneumatic Sealing Industry Association in 1998, the production and sales rate of hydraulic products was 97.5% (101% of hydraulic power), 95.9% of air pressure, and 98.7% of seal. This fully reflects the basic convergence of production and sales.Although China's hydraulic, pneumatic and sealing industries have made great progress, there are still many gaps compared with the development needs of the mainframe and the world's advanced level, which are mainly reflected in the variety, performance and reliability of products. . Take hydraulic products as an example, the product varieties are only 1/3 of the foreign country, and the life expectancy is 1/2 of that of foreign countries. In order to meet the needs of key hosts, imported hosts, and majortechnical equipment, China has a large number of imported hydraulic, pneumatic, and sealing products every year. According to customs statistics and relevant data analysis, in 1998, the import volume of hydraulic, pneumatic and seal products was about 200 million U.S. dollars, of which the hydraulic pressure was about 140 million U.S. dollars, the pneumatics were 30 million U.S. dollars, and the seal was about 0.3 billion U.S. dollars. The year is slightly lower. In terms of amount, the current domestic market share of imported products is about 30%. In 1998, the total demand for hydraulic parts in the domestic market was about 6 million pieces, and the total sales volume was 4 billion yuan; the total demand for pneumatic parts was about 5 million pieces, and the total sales volume was over 700 million yuan; the total demand for seals was about 1.1 billion yuan. Pieces, total sales of about 1.3 billion yuan. (3) Future developments1. The main factors affecting development(1) The company's product development capability is not strong, and the level and speed of technology development can not fully meet the current needs for advanced mainframe products, major technical equipment and imported equipment and maintenance;(2) Many companies have lagged behind in manufacturing process, equipment level and management level, and their sense of quality is not strong, resulting in low level of product performance, unstable quality,poor reliability, and insufficiency of service, and lack of user satisfaction. And trusted branded products;(3) The degree of professional specialization in the industry is low, the power is scattered, the duplication of the low level is serious, the product convergence between the region and the enterprise leads to blind competition, and the prices are reduced each other, thus the efficiency of the enterprise is reduced, the funds are lacking, and the turnover is difficult. Insufficient investment in development and technological transformation has severely restricted the overall level of the industry and its competitive strength.(4) When the degree of internationalization of the domestic market is increasing, foreign companies have gradually entered the Chinese market to participate in competition, coupled with the rise of domestic private, cooperative, foreign-funded, and individual enterprises, resulting in increasing impact on state-owned enterprises. .2. Development trendWith the continuous deepening of the socialist market economy, the relationship between supply and demand in the hydraulic, pneumatic and sealed products has undergone major changes. The seller market characterized by “shortage” has basically become a buyer’s market characterized by “structured surplus”. Replaced by. From the perspective of overall capacity, it is already in a trend of oversupply, and in particular,general low-grade hydraulic, pneumatic and seals are generally oversupply; and like high-tech products with high technological content and high value and high value-added products that are urgently needed by the host, Can not meet the needs of the market, can only rely on imports. After China's entry into the WTO, its impact may be greater. Therefore, during the “10th Five-Y ear Plan” period, the growth of the industry’s output value must not only rely on the growth of quantity. Instead, it should focus on the structural contradiction of the industry and intensify efforts to adjust the industrial structure and product structure. It should be based on the improvement of quality. Product technology upgrades in order to adapt to and stimulate market demand, and seek greater development.2. Hydraulic application on power slide(1) Introduction of Power Sliding TableUsing the binding force curve diagram and the state space analysis method to analyze and study the sliding effect and the smoothness of the sliding table of the combined machine tool, the dynamics of the hydraulic drive system of the sliding table—the self-regulating back pressure regulating system are established. mathematical model. Through the digital simulation system of the computer, the causes and main influencing factors of the slide impact and the motion instability are analyzed. What kind of conclusions can be drawn from those, if we canreasonably design the structural dimensions of hydraulic cylinders and self-regulating back pressure regulators ——The symbols used in the text are as follows:s 1 - flow source, that is, the flow rate of the governor valve outlet;S el —— sliding friction of the sliding table;R - the equivalent viscous friction coefficient of the slide;I 1 - quality of slides and cylinders;12 - self-adjusting back pressure valve core quality;C 1, c 2 - liquid volume without cylinder chamber and rod chamber;C 2 - Self-adjusting back pressure valve spring compliance;R 1, R2 - Self-adjusting back pressure valve damping orifice fluid resistance;R 9 - Self-adjusting back pressure valve valve fluid resistance;S e2——initial pre-tightening force of self-adjusting back pressure valve spring;I 4, I5 - Equivalent liquid sense of the pipeline;C 5, C 6 - equivalent liquid capacity of the pipeline;R 5, R7 - Equivalent liquid resistance of the pipeline;V 3, V4 - cylinder rodless cavity and rod cavity volume;P 3, P4—pressure of the rodless cavity and rod cavity of the cylinder;F - the slide bears the load;V - speed of slide motion;In this paper, the power bond diagram and the state space splitting method are used to establish the system's motion mathematical model, and the dynamic characteristics of the slide table can be significantly improved.In the normal operation of the combined machine tool, the magnitude of the speed of the slide, its direction and the load changes it undergoes will affect its performance in varying degrees. Especially in the process of work-in-process, the unsteady movement caused by the advancing of the load on the slide table and the cyclical change of the load will affect the surface quality of the workpiece to be machined. In severe cases, the tool will break. According to the requirements of the Dalian Machine Tool Plant, the author used the binding force curve diagram and the state space analysis method to establish a dynamic mathematical model of a self-adjusting back pressure and speed adjustment system for the new hydraulic drive system of the combined machine tool slide. In order to improve the dynamic characteristics of the sliding table, it is necessary to analyze the causes and main influencing factors of the impetus and movement of the sliding table. However, it must pass the computer's digital simulation and the final results obtained from the research.(2) Dynamic Mathematical ModelThe working principle diagram of the self-adjusting back pressure speedregulation system of the combined machine tool slide hydraulic drive system is shown in the figure. This system is used to complete the work-cycle-stop-rewind. When the sliding table is working, the three-position four-way reversing valve is in the illustrated position. The oil supply pressure of the oil pump will remain approximately constant under the effective action of the overflow valve, and the oil flow passes through the reversing valve and adjusts the speed. The valve enters the rodless chamber of the cylinder to push the slide forward. At the same time, the pressurized oil discharged from the rod chamber of the cylinder will flow back to the tank through the self-regulating back pressure valve and the reversing valve. During this process, there was no change in the operating status of both the one-way valve and the relief valve. The complex and nonlinear system of the hydraulic drive system of the self-adjusting back pressure governor system is a kind of self-adjusting back-pressure governor system. To facilitate the study of its dynamic characteristics, a simple and reasonable dynamic mathematical model that only considers the main influencing factors is established. Especially important [1][2]. From the theoretical analysis and the experimental study, we can see that the system process time is much longer than the process time of the speed control valve. When the effective pressure bearing area of the rodless cavity of the fuel tank is large, the flow rate at the outlet of the speed control valve is instantaneous. The overshoot is reflected in thesmall change in speed of the slide motion [2]. In order to further broaden and deeply study the dynamic characteristics of the system so that the research work can be effectively performed on a miniature computer, this article will further simplify the original model [2], assuming that the speed control valve is output during the entire system pass. When the flow is constant, this is considered to be the source of the flow. The schematic diagram of the dynamic model structure of this system is shown in Fig. 2. It consists of a cylinder, a sliding table, a self-adjusting back pressure valve, and a connecting pipe.The power bond graph is a power flow graph. It is based on the transmission mode of the system energy, based on the actual structure, and uses the centralized parameters to represent the role of the subsystems abstractly as a resistive element R, a perceptual element I, and a capacitive element. Three kinds of role of C. Using this method, the physical concept of modeling is clear, and combined with the state-space analysis method, the linear system can be described and analyzed more accurately. This method is an effective method to study the dynamic characteristics of complex nonlinear systems in the time domain. According to the main characteristics of each component of the self-adjusting back pressure control system and the modeling rules [1], the power bond diagram of the system is obtained. The upper half of each key in the figure represents the power flow. The two variables that makeup the power are the force variables (oil pressure P and force F) and the flow variables (flow q and velocity v). The O node indicates that the system is connected in parallel, and the force variables on each key are equal and the sum of the flow variables is zero; 1 The nodes represent the series connection in the system, the flow variables on each key are equal and the sum of the force variables is Zero. TF denotes a transformer between different energy forms. The TF subscripted letter represents the conversion ratio of the flow variable or the force variable. The short bar on the key indicates the causal relationship between the two variables on the key. The full arrow indicates the control relationship. There are integral or differential relationships between the force and flow variables of the capacitive and perceptual elements in the three types of action elements. Therefore, a complex nonlinear equation of state with nine state variables can be derived from Fig. 3 . In this paper, the research on the dynamic characteristics of the sliding table starts from the two aspects of the slide's hedging and the smoothness of the motion. The fourth-order fixed-length Runge-Kutta is used for digital simulation on the IBM-PC microcomputer.(3) Slide advanceThe swaying phenomenon of the slide table is caused by the sudden disappearance of the load acting on the slide table (such as drilling work conditions). In this process, the table load F, the moving speed V, and thepressure in the two chambers of the cylinder P3 and P4 can be seen from the simulation results in Fig. 4. When the sliding table moves at a uniform speed under the load, the oil pressure in the rodless cavity of the oil cylinder is high, and a large amount of energy is accumulated in the oil. When the load suddenly disappears, the oil pressure of the cavity is rapidly reduced, and the oil is rapidly reduced. When the high-pressure state is transferred to the low-pressure state, a lot of energy is released to the system, resulting in a high-speed forward impact of the slide. However, the front slide of the sliding table causes the pressure in the rod cavity of the oil cylinder to cause the back pressure to rise, thereby consuming part of the energy in the system, which has a certain effect on the kicking of the slide table. We should see that in the studied system, the inlet pressure of the self-adjusting back pressure valve is subject to the comprehensive effect of the two-chamber oil pressure of the oil cylinder. When the load suddenly disappears, the pressure of the self-adjusting back pressure valve rapidly rises and stably exceeds the initial back pressure value. It can be seen from the figure that self-adjusting back pressure in the speed control system when the load disappears, the back pressure of the cylinder rises more than the traditional speed control system, so the oil in the rod cavity of the cylinder absorbs more energy, resulting in the amount of forward momentum of the slide It will be about 20% smaller than traditionalspeed control systems. It can be seen from this that the use of self-adjusting back-gear speed control system as a drive system slider has good characteristics in suppressing the forward punch, in which the self-adjusting back pressure valve plays a very large role.(4) The smoothness of the slideWhen the load acting on the slide changes periodically (such as in the case of milling), the speed of the slide will have to fluctuate. In order to ensure the processing quality requirements, it must reduce its speed fluctuation range as much as possible. From the perspective of the convenience of the discussion of the problem, assume that the load changes according to a sine wave law, and the resulting digital simulation results are shown in Figure 5. From this we can see that this system has the same variation rules and very close numerical values as the conventional speed control system. The reason is that when the change of the load is not large, the pressure in the two chambers of the fuel tank will not have a large change, which will eventually lead to the self-regulating back pressure valve not showing its effect clearly.(5) Improvement measuresThe results of the research show that the dynamic performance of a sliding table with self-regulating back pressure control system as a drive system is better than that of a traditional speed control system. To reduce the amount of kick in the slide, it is necessary to rapidly increase the backpressure of the rod cavity when the load disappears. To increase the smoothness of the sliding table, it is necessary to increase the rigidity of the system. The main measure is to reduce the volume of oil. From the system structure, it is known that the cylinder has a large volume between the rod cavity and the oil discharge pipe, as shown in Fig. 6a. Its existence in terms of delay and attenuation of the self-regulating back pressure valve function, on the other hand, also reduces the rigidity of the system, it will limit the further improvement of the propulsion characteristics and the smoothness of the motion. Thus, improving the dynamic characteristics of the sliding table can be handled by two methods: changing the cylinder volume or changing the size of the self-regulating back pressure valve. Through the simulation calculation of the structural parameters of the system and the comparison of the results, it can be concluded that the ratio of the volume V4 between the rod cavity and the oil discharge pipe to the volume V3 between the rodless cavity and the oil inlet pipe is changed from 5.5 to 5.5. At 1 oclock, as shown in the figure, the diameter of the bottom end of the self-adjusting back pressure valve is increased from the original 10mm to 13mm, and the length of the damper triangle groove is reduced from the original lmm to 0.7mm, which will enable the front of the slide table. The impulse is reduced by 30%, the transition time is obviously shortened, and the smoothness of the slide motion will also be greatly improved.中文译文液压系统W Arnold1. 绪论液压站称液压泵站,是独立的液压装置。
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。
液压方面的英语词汇
液压方面的英语单词目录按字母排序 (1)按分类排序 (10)其他总结的词汇 (13)按字母排序Aability 性能；能力load-carrying ability 承载能力absorber 吸收器；吸收剂；过滤器；减震器accessories 辅件，附件，配件hydraulic accessories 液压辅件accumulate 储存；蓄能；累积accumulator 蓄能器；蓄电池；累加器accuracy 准确性；精度action 作用；动作；作用力；行程actuated 操纵，控制directly actuated 直接操纵的，直接控制的pilot actuated 先导控制的，液控的actuator 执行元件；液压缸；马达adapter 接头；衬套；压环；连接件pipe adapter 管接头admission 供给，供油，供气alignment 找正，定心，对中amplifier 放大器differential pressure amplifier 压差放大器flow amplifier 流量放大器assembly 组合，组件，机组axis 轴Bback-flow 回流back-up 支撑hydrostatic back-up 静压支撑barrel 桶，缸体base 底座；支座bearing 支承；轴承；方位radial ball bearing 径向球轴承rolling bearing 滚动轴承sliding bearing 滑动轴承thrust bearing 止推轴承bed 台pump test bed 泵试验台behavior 性能；工况bend 弯头；弯管blade 叶片flat blade 平面叶片forward inclined blade 前倾叶片guide blade 导叶radial blade 径向叶片bleed 排气air bleed 排气阀bleeder 排气孔block 块；封闭；块体cartridge valve block 插装阀块体choke block 节流板directional control block 多路阀，方向控制阀组panel block 阀板组body 体；缸筒；阀体，壳体pump body 泵体tank body 箱体valve body 阀体bolt 螺栓；插销；螺杆boss 轮毂bottom 底；底部cylinder bottom 缸底；缸后盖bracket 支架pump bracket 泵架bubble-tight 气密的buffer 缓冲器，阻尼器bush(ing) 套，导向套；衬套Ccap 帽,盖,罩,塞cylinder end cap 缸端盖cylinder head cap 缸前盖capacity 容量;功率;排量;流量effective capacity 有效排量,实际排量geometric capacity 几何排量,理论排量casing 套,壳,罩gear casing 齿轮箱，变速箱pump casing 泵体cavitation 气蚀cavity 腔centering 中心调整，定心chamber 腔，室；容积；油腔；气腔chamfer 槽；倒角changement 换向机构characteristic 特性曲线；特征线charger 加载装置charging 充液；充压choke 节流；节流口chord 弦circlip 弹性挡圈circuit 回路clearance 间隙clog 阻塞；堵塞cock 龙头collar 圈；法兰盘cushion collar 缓冲套locating collar 定位凸缘套loose collar 轴肩挡圈thrust collar 止推环connection 连接；连接管路；接头consumption 消耗量cylinder 缸；液压缸Ddebugging 排除故障；调试deflation 排气delivery 流量differential 差动的；微分的displacement 压出；排出；排量；位移dowel 定位销drained 泄油的duty 负载，功率；工况Eeffect 作用;效应cavitate effect 气蚀效应choking effect 节流作用elbow 弯头electro-hydraulic 电液的entrap 困油escape 泄漏,逸出,排出etching 蚀刻;腐蚀gas etching 气蚀exhaust 排泄;回油;Ffailure 故障;事故;损坏,失效fastener 紧固件fatigue 疲劳feedback 反馈filler 加油口,注油口;填料;垫片filter 滤油器flow 流;液流;流程;流束;流量;流动nominal flow 公称流量rated flow 额定流量stationary flow 定常流,定常流动streamline flow 层流turbulent flow 紊流volume flow 体积流量flowline 管路;流线flow-regulator 流量调节阀fluctuation 脉动fluid 流体,液体;射流hydraulic operating fluid 液压油incompressible fluid 不可压缩流体frame 座,架Ggain 增益flow gain 流量增益feedback gain 反馈增益gap 间隙,缝隙gear 齿轮,装置,机构governing 调节,控制Hhead 缸头,头部;盖;水头;扬程cylinder head 缸头static head 静压头theoretic head 理论能头total head 总能头water head 水头hole 孔,洞air hole 气孔blind hole 盲孔bolt hole 螺栓孔bose 胶管,软管housing 壳体;槽hub 毂;衬套hydrostatics 液压技术,液体静力学Iidling 空转impact 冲击,撞击impeller 叶轮closed impeller 闭式叶轮open impeller 开式叶轮pump impeller 泵叶轮incidence 入射;入射角blade incidence 叶片安装角incompressible 不可压缩的inlet 进口;吸入intensifier 增压器intensity 强度Jjack (柱塞)缸;千斤顶joint 接头;关节cross joint 十字接头flange joint 法兰式接头screwed joint 螺纹接头journal 轴颈jump 跳动;振动pressure jump 压力突变Kkeyway 键槽Llag 滞后;延迟servovalve phase lag 伺服阀相位滞后laminar 层流的latch 插销;锁紧装置;锁定leak 漏;漏油;渗漏处;漏出物line 管路;线路liner 衬套;导向套;内层胶liquid 液体(的);液力的load 负载;载荷location 位置;定位;安装lock 锁;闭锁;液压卡紧loop 环;环路;回路;循环control loop 控制回路,调节回路main loop 主回路servo loop 伺服回路loss 损失bend loss 弯头损失blade loss 叶片损失line loss 管路损失local pressure loss 局部压力损失partial loss 局部损失lubricate 润滑lug 耳轴lifting lug 吊环Mmandrel 心轴;芯棒manometer 压力机,压力表meter 米;仪表;计量;节制;控制(流量);流量计meter-in 进口节流meter-out 出口节流motion 动作alternative motion 往复运动lost motion 空转synchronized motion 同步运动motor 发动机,液压马达axial piston motor 轴向柱塞马达bent axis piston motor 斜轴式轴向柱塞马达cam plate type axial piston motor 斜盘式轴向柱塞马达constant displacement motor 定量马达radial motor 径向马达sliding vane motor 叶片马达swing motor 摆动马达Nnominal 额定的,公称的notch 凹槽relief notch 卸荷槽null 零位Ooff-load 卸荷oil 油oiler 注油器olive 球面卡套grooved olive 迷宫密封环operation 运行;操作;运算orifice 小孔;节流孔O-ring O型密封圈output 输出;排量;流量overload 过载Ppack 包,捆;组合件,部件,单元power pack 液压泵站package包,捆;组件,单元hydraulic package 液压泵站power package 泵站packing 密封;密封装置;填料密封pad 衬垫;底座asbestos pad 石棉垫valve pad 阀垫parameter 参数part 部分;零件;部件partition 隔板passage 流道;通道;通过pedestal 支座,底座motor pedestal 电动机座phenomenon 现象stick-alip phenomenon 爬行现象trapping phenomenon 困油现象piece 零件,部件pilot(-actuate,-operate) 先导控制;液控piloted 先导控制的pin 销;插头alignment pin 定位销cottar pin 开口销locking pin 锁紧销piston pin 活塞销straight pin 圆柱销pipe 管子,管道(尤指铸铁管和钢管) piston 活塞;柱塞;阀芯double acting piston 双作用活塞double rod piston 双杆活塞hollow piston 空心活塞single-rod piston 单杆活塞pit 坑;槽pitch 节距pitting 凹痕;锈斑;点蚀plug 堵塞;阻塞;堵头air release plug 排气塞plug-in 插入式的,组合式的poppet 提动阀芯,座阀芯,锥阀芯,碟形阀芯pore 孔;孔隙port 油口;连接口position 位置;状态;定位center valve position 阀的中间位置neutral position 中位;零位three position 三位two position 二位pressure 压力,压强;气压pulsation 脉动,波动pump 泵bent axis axial piston pump 斜轴式轴向柱塞泵booster pump 辅助泵,充液泵cam plate type axial piston pump 斜盘式轴向柱塞泵centrifugal pump 离心泵constant delivery pump 定量泵cycloid rotor pump 摆线转子泵double action vane pump 双作用叶片泵gear pump 齿轮泵multi-stage pump 多级泵single action vane pump 单作用叶片泵vane pump 叶片泵variable capacity pump 变量泵Rrabbet 球铰rack 齿条;机架racing 空转radian 弧度radius 半径range 范围,量程rated 额定的regulation 调节,调整regulator 调节器,调压阀differential pressure regulator 定差减压阀proportional pressure regulator 定比减压阀relay 继电器relief 释压;溢流;卸荷reset 复位restriction 节流;阻尼,节流口,阻尼孔restrictor 节流阀;节流口;阻尼孔reversal 反转,倒转revolution 旋转;转数rider 导向套ring 环,圈anti-extrusion ring 密封挡圈,挡圈back support ring 后支承环back-up ring 挡圈bearing ring 导向套dust ring 防尘圈retainer ring 卡环seal ring 密封圈;密封环rod 杆;活塞杆Sscrew 螺杆,螺钉,丝杆,螺旋seal 密封;封口;密封件;密封装置seat 阀座,座seizure 卡死,咬住,擦伤selector 换向阀servo 伺服;伺服机构,伺服系统servomotor 伺服马达servopump 伺服泵servovalve 伺服阀set 组件;定位;集合shaft 轴pump shaft 泵轴sleeve 套;套管;卡套;阀套slot 缝,隙,槽spring 弹簧stroke 行程symbol 符号functional symbol 职能符号Ttank 箱,缸;油箱;容器tee 三通接头,三通throttle 节流;节流阀trapping 困油travel 位移;行程tube 管子(尤指有色金属和无缝钢管) tubeline 管路Uunion 中间接头;直通接头Vvalve 阀back pressure valve 背压阀bypass valve 旁通阀;溢流阀change valve 换向阀check valve 单向阀direct operated solenoid valve 电磁阀flow regulating valve 调速阀four port valve 四通阀four position valve 四位阀hand operated valve 手动阀hydraulic operated check valve 液控单向阀overflow valve 溢流阀overload relief valve 安全阀;过载溢流阀piloted valve 先导式阀vane 叶片diffusion vane 导叶vent 放气;排气孔volume 容积,体积displacement volume 排量Wwasher 垫圈;衬垫wiper 防尘圈Zzone 地带;区(域)dead zone 死区high pressure zone 高压区low pressure zone 低压区按分类排序一、阀类出口节流回路meter-out circuit同步回路synchronizing circuit开式回路open circuit闭式回路closed circuit管路布置pipe-work管卡clamper联轴器drive shaft coupling操作台control console控制屏control panel避震喉compensator粘度viscosity运动粘度kinematic viscosity密度density含水量water content闪点flash point防锈性rust protection抗腐蚀性anti-corrosive quality便携式颗粒检测仪portable particle counter 电磁阀Solenoid valve单向阀Check valve插装阀Cartridge valve叠加阀Sandwich plate valve先导阀Pilot valve液控单向阀Pilot operated check valve板式安装Sub-plate mount集成块Manifold block压力溢流阀Pressure relief valve流量阀Flow valve节流阀Throttle valve双单向节流阀Double throttle check valve 旋钮Rotary knob节流板Rectifier plate伺服阀Servo valve比例阀Proportional valve位置反馈Position feedback渐增流量Progressive flow电磁铁释放De-energizing of solenoid二、介质类磷酸甘油酯Phosphate ester (HFD-R)水-乙二醇Water-glycol (HFC)乳化液Emulsion缓蚀剂Inhibitor合成油Synthetic lubricating oil三、液压安装工程污染Contamination灌浆Grout失效Failure点动Jog爬行Creep摩擦Abrasion（活塞杆）伸出Retract（活塞杆）缩回Extension误动作Malfunction酸洗Pickling冲洗Flushing槽式酸洗Dipping process循环Re-circulation钝化Passivity柠檬酸Nitric acid氩气Argon对接焊Butt welding套管焊Socket welding惰性气体焊Inert gas welding四、管接头Bite type fittings 卡套式管接头Tube to tube fittings接管接头union 直通接管接头union elbow 直角管接头union tee 三通管接头union cross 四通管接头Mal stud fittings 端直通管接头Bulkhead fittings 长直通管接头Weld fittings 焊接式管接头Female connector fittings 接头螺母Reducers extenders 变径管接头Banjo fittings 铰接式管接头Adjustable fittings/swivel nut 旋转接头五、伺服阀及伺服系统性能参数Dynamic response 动态频响DDV-direct drive valve 直动式伺服阀NFPA-National Fluid Power Association 美国流体控制学会Phase lag 相位滞后Nozzle flapper valve 喷嘴挡板阀Servo-jet pilot valve 射流管阀Dither 颤振电流Coil impedance 线圈阻抗Flow saturation 流量饱和Linearity 线形度Symmetry 对称性Hysterics 滞环Threshold 灵敏度Lap 滞后Pressure gain 压力增益Null 零位Null bias 零偏Null shift 零飘Frequency response 频率响应Slope 曲线斜坡液压系统（hydraulic system）执行元件（actuator）液压缸（cylinder）液压马达（motor）液压回路（circuit）压力控制回路（pressure control）流量（速度）控制回路（speed control）方向控制回路（directional valve control）安全回路（security control）定位回路（position control）同步回路（synchronise circuit）顺序动作回路（sequeunt circuit）液压泵（pump）阀（valve）压力控制阀（pressure valve）流量控制阀（flow valve）方向控制阀（directional valve）液压辅件（accessory）普通阀（common valve）其他总结的词汇流体传动hydraulic power液压技术hydraulics液力技术hydrodynamics气液技术hydropneumatics运行工况operating conditions额定工况rated conditions极限工况limited conditions瞬态工况instantaneous conditions稳态工况steady-state conditions许用工况acceptable conditions连续工况continuous working conditions 实际工况actual conditions效率efficiency旋转方向direction of rotation公称压力nominal pressure工作压力working pressure进口压力inlet pressure出口压力outlet pressure压降pressure drop；differential pressure背压back pressure启动压力breakout pressure充油压力charge pressure开启压力cracking pressure峰值压力peak pressure运行压力operating pressure耐压试验压力proof pressure冲击压力surge pressure静压力static pressure系统压力system pressure控制压力pilot pressure充气压力pre-charge pressure吸入压力suction pressure调压偏差override pressure额定压力rated pressure耗气量air consumption泄漏leakage内泄漏internal leakage外泄漏external leakage层流laminar flow紊流turbulent flow气穴cavitation流量flow rate排量displacement额定流量rated flow供给流量supply flow流量系数flower factor滞环hysteresis图形符号graphical symbol液压气动元件图形符号symbols for hydraulic and pneumatic components 流体逻辑元件图形符号symbols for fluid logic devices逻辑功能图形符号symbols for logic functions回路图circuit diagram压力－时间图pressure time diagram功能图function diagram循环circle自动循环automatic cycle工作循环working cycle循环速度cycling speed工步phase停止工步dwell phase工作工步working phase快进工步rapid advance phase快退工步rapid return phase频率响应frequency response重复性repeat ability复现性reproducibility漂移drift波动ripple线性度linearity线性区linear region液压锁紧hydraulic lock液压卡紧sticking变量泵variable displacement pump 泵的控制control of pump齿轮泵gear pump叶片泵vane pump柱塞泵piston pump轴向柱塞泵axial piston pump法兰安装flange mounting底座安装foot mounting液压马达hydraulic motor刚度stiffness中位neutral position零位zero position自由位free position缸cylinder有杆端rod end无杆端rear end外伸行程extend stroke内缩行程retract stroke缓冲cushioning工作行程working stroke负载压力induced pressure输出力force实际输出力actual force单作用缸single-acting cylinder双作用缸double-acting cylinder差动缸differential cylinder伸缩缸telescopic cylinder阀valve底板sub-plate油路块manifold block板式阀sub-plate valve叠加阀sandwich valve插装阀cartridge valve滑阀slide valve锥阀poppet valve阀芯valve element阀芯位置valve element position单向阀check valve液控单向阀pilot-controlled check valve 梭阀shuttle valve压力控制阀pressure relief valve溢流阀pressure relief valve顺序阀sequence valve减压阀pressure reducing平衡阀counterbalance valve卸荷阀unloading valve直动式directly operated type先导式pilot-operated type机械控制式mechanically controlled type 手动式manually operated type液控式hydraulic controlled type流量控制阀flow control valve固定节流阀fixed restrictive valve可调节流阀adjustable restrictive valve 单向节流阀one-way restrictive valve调速阀speed regulator valve分流阀flow divider valve集流阀flow-combining valve截止阀shut-off valve球阀global(ball) valve针阀needle valve闸阀gate valve膜片阀diaphragm valve蝶阀butterfly valve噪声等级noise level放大器amplifier模拟放大器analogue amplifier数字放大器digital amplifier传感器sensor阈值threshold伺服阀servo-valve四通阀four-way valve喷嘴挡板nozzle flapper液压放大器hydraulic amplifier颤振dither阀极性valve polarity流量增益flow gain对称度symmetry流量极限flow limit零位内泄漏null(quiescent) leakage 遮盖lap零遮盖zero lap正遮盖over lap负遮盖under lap开口opening零偏null bias零漂null drift阀压降valve pressure drop分辨率resolution频率响应frequency response幅值比amplitude ratio相位移phase lag传递函数transfer function管路flow line硬管rigid tube软管flexible hose工作管路working line回油管路return line补液管路replenishing line控制管路pilot line泄油管路drain line放气管路bleed line接头fitting；connection焊接式接头welded fitting扩口式接头flared fitting快换接头quick release coupling法兰接头flange connection弯头elbow异径接头reducer fitting流道flow pass油口port闭式油箱sealed reservoir油箱容量reservoir fluid capacity气囊式蓄能器bladder accumulator 空气污染air contamination固体颗粒污染solid contamination 液体污染liquid contamination空气过滤器air filter油雾气lubricator热交换器heat exchanger冷却器cooler加热器heater温度控制器thermostat消声器silencer双筒过滤器duplex filter过滤器压降filter pressure drop有效过滤面积effective filtration area公称过滤精度nominal filtration rating压溃压力collapse pressure填料密封packing seal机械密封mechanical seal径向密封radial seal旋转密封rotary seal活塞密封piston seal活塞杆密封rod seal防尘圈密封wiper seal；scraper组合垫圈bonded washer复合密封件composite seal弹性密封件elastomer seal丁腈橡胶nitrile butadiene rubber；NBR 聚四氟乙烯polytetrafluoroethene；PTFE 优先控制override control压力表pressure gauge压力传感器electrical pressure transducer 压差计differential pressure instrument液位计liquid level measuring instrument 流量计flow meter压力开关pressure switch脉冲发生器pulse generator液压泵站power station空气处理单元air conditioner unit压力控制回路pressure control circuit安全回路safety circuit差动回路differential circuit调速回路flow control circuit进口节流回路meter-in circuit。
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Variable Speed Hydraulic SystemIt is particularly important on many hydraulic system, as on machine tools, to be able to vary the speed of operation at will .This can be carried out in the following ways, sometimes more than one way being combined:a.By varying the pump output manually;b.By using several pumps in combinations;c.By restricting or throttling the output of a automatically variable delivery pump,or a pump accumulator system, or by throttling the inlet;d.By by-passing part of the pump output with a flow dividing valve;e.By varying the volume of the operating jack.1、Variation in Pump Delivery. Pump delivery can be varied bya.Alteration in its speed;b.Alteration of its stroke in a variable stroke type of pump;ing two or more pumps of different delivery in parallel so that by stopping andstarting the pumps in various combinations different total deliveries can obtained.The first system is an easy one when the pump is electrically driven, although the electric motor involved is comparatively complicated dor normal requirements. Mechanical variable speed gear boxes have been used successfully with constant speed electric drive.Several of the pump mechanisms previously described can readily be adapted to five a varying output by reducing the working strok manually by means of a control wheel, etc.The third system is simple enough, but varies the output in fixed steps. Two pumps n parallel can give three ranges of output corresponding toPump A, Pump B, Pump A Plus B.Three pumps in parallel can give seven steps corresponding toPump A, Pump A Plus B, Pump B Plus C,Pump B, Pump A Plus C, Pump A Plus B Puls C.Pump C,Since, however, variable stroke pumps are readily available,such a complication as three pumps in parallel hardly seems worthwhile although the two-pump system is probably excellent for such duties as presses, etc. , where a great part of the workingstroke is at low pressure, where a relatively cheap type of pump can be used, cutting out in favour of a smaller delivery high pressure pump for the final working stroke. Automatic isolation of the low pressure pump can be effected by a valve. Any normal type of automatic cutout will operate in the low-pressure system to by-pass it, without interference from the other pump.2、Restriction of Pump Output. With a variable delivery pump the flow of oil to the system proper can be metered through a restriction, the delivery of the pump automatically adjusting itself to the reduced flow. An automatic flow control valve or throttle is to be preferred to a simple restrictor. This is an extremely simple system, but is liable to variation of speed owing to change in viscosity of the oil, temperature effects, etc., and the metering restriction may have to be adjusted from time to time to keep the speed constant. On the other hand, it is possible to evolve a restriction compensated for changes. By fitting the flow control valve in either jack line, control in one directions only can be exercised, but note that as the volumes of the jack returning to tank may not be the same in both directions, the degree of speed control may not be similar.3、Use of Flow dividing Valves. The flow dividing valves of various types are used to control the speed of a system by by-passing part of the pump output, even if at the expense of a slight wastage of power. It is possible to use a selector incorporating several ports, which in turn control the flow of fluid past several different flow dividing valves, giving different rates of flow for each position of the selector.4、Variation in Jack Volume. Another means of obtaining Variable speed from a constant delivery pump is to use jacks of different volumes(i. e. at different pressures), either in parallel, or using a multivolume construction. If, for example, the machine tool slide, etc., is fitted with two operating jacks, by suitable selection varying speed of operation can be obtained corresponding toe of jack A;e of jack B;e of jack A and B together.If B=2A, the speeds are in the order 1, 2, 3. The combination of two jacks and two pumps can obviously give 9 speeds, but at the expense of considerably more complication than would appear to be present with a variable delivery pump.变速液压装置许多液压装置，如像机床上用的，其操作速度能随意变化，那显得特别重要，这种变速可以以下方法，有时以一个以上的方法相结合来实现。
a 用手动控制改变泵的输出b 利用几台泵组合c 靠自动节流调节输送泵的输出量，或靠泵的蓄压器装置，抑或借助入口节流调节d 通过泵的旁路，经分流阀输出e 操纵动力油缸改变流量1．泵送量的变化。
泵的输送量可以靠以下方法变化：a 其速度变化b 在可变冲程泵中，改变其冲程c 利用两台或更多的泵并联送出不同的输送量因此借助不同的组合来启、停这些泵，可以获得不同输出总量。