液压系统外文资料翻译
液压动力系统中英文对照外文翻译文献
中英文对照外文翻译文献(文档含英文原文和中文翻译)原文：FEATURE-BASED COMPONENT MODELS FOR VIRTUALPROTOTYPING OF HYDRAULIC SYSTERMAbstract:This paper proposes a feature-based approach for the virtual prototyping of hydraulic systems. It presents a framework which allows the designer to develop a virtual hydraulic system prototype in a more intuitive manner, i.e. through assembly of virtual components with engineering data. The approach is based on identifying the data required for the development of the virtual prototypes, and separating the information into behaviour, structural, and product attributes. Suitable representations of these attributes are presented, and the framework for the feature-based virtual prototyping approach is established,based on the hierarchical structure of components in a hydraulic system. The proposed framework not only provides a precise model of the hydraulic prototype but also offers the possibility of designing variation classes of prototypes whose members are derived by changing certain virtual components with different features.Key words: Computer-aided engineering; Fluid power systems;Virtualprototyping1.IntroductionHydraulic system design can be viewed as a function-to-form transformation process that maps an explicit set of requirements into a physical realisable fluid power system. The process involves three main stages: the functional specification stage,the configuration design stage, and the prototyping stage.The format for the description of the design in each stage is different.The functional specification stage constitutes the initial design work. The objective is to map the design requirements. To achieve this, the design problems are specified Correspondence and offprint requests to: Dr S. C. Fok, Schoool of Mechanical and Production Engineering, Nanyang Technological University, Nanyang Avenue, Singapore 639798. The designer must identify the performance attributes, which can include pressure, force, speed, and flowrate, with the required properties such as size, cost, safety and operating sequence. performance requirements for each attribute. In this stage, the design is abstracted in terms of the performance attributes with associated values.The objective of the configuration design stage is to synthesise a hydraulic circuit that performs the required functions conforming to the performance standards within defined constraints. A typical hydraulic system is made up of many subsystems. The smallest building block in a subsystem is the standard hydraulic component (such as valves, cylinders,pumps, etc.). Each type of standard component serves a specific elemental function. The design effort in the configuration design stage is fundamentally a search for a set of optimal arrangements of standard components (i.e. hydraulic circuit) to fulfil the functional requirements of the system. Based on this framework, the designers would normally decompose the overall system functions in terms of subfunctions. This will partition the search space and confine the search for smaller hydraulic subcircuits to perform the subfunctions.Computers are often used to support the configuration design process. For example, Kota and Lee devised a graph-based strategy to automate the configuration of hydraulic circuits. After the development of the hydraulic circuits, digital simulation tools are often used to study and evaluate these configurations. With these tools, designers can compare the behaviour of different circuits and also analyse the effects when subcircuits are combined. In the configuration design stage, the design is traditionally represented as a circuit drawing using standard icons to symbolise the type of standard component. This is a form of directed graph S(C,E) where the circuit S contains components C in the form of nodes with relations between components denoted by edges E.The prototyping stage is the verification phase of the system design process where the proposed hydraulic circuit from the configuration design stage isdeveloped and evaluated. Physical prototyping aims to build a physical prototype of the hydraulic system 666 S. C. Fok et al. using industrial available components. The process of physical prototyping involves the following: Search for appropriate standard components from different manufacturers. Pre-evaluation and selection of components based on individual component cost, size, and specification, and compatibility factors between components. Procurement and assembly of the selected components.Test and evaluate the physical prototype based on the overall system requirements. Use other components or redesign the circuit (or subcircuits)if necessary.Besides dynamics, the development of the physical prototype must take into consideration other factors including structure,cost, and weight. The dynamics data are used to confirm the fluid power system behaviour whereas the geometric information is used to examine the assembly properties. The development of the physical prototype will provide the actual performance,structure, and cost of the design.The main disadvantage of physical prototyping is that it is very tedious and time consuming to look for a set of suitable combinations of standard components from among so many manufacturers. Although the basic functions of the same types of standard component from different manufacturers do not differ, their dynamics, structural and cost characteristics may not be similar, because of design variation. Hence, for a given hydraulic circuit, different combinations of parts from differentmanufacturers can have implications on the resulting system,in terms of dynamics, structure, and cost. Value engineering can be used at this stage to improve the system design by improving the attributes at the component level. This includes maximizing the performance-to-cost ratio and minimising the size-to-performance ratio. Virtual prototyping can be viewed as a computer-aided design process, which employs modelling and simulating tools to address the broad issues of physical layout, operationalconcept, functional specifications, and dynamics analysis under various operating environments. The main advantage of virtual prototyping is that a hydraulic system prototype can be assembled, analysed, and modified using digital computers without the need for physical components, thus saving lead time and cost.The main requirement of a virtual hydraulic system prototype is to provide the same information as a physical prototype for the designer to make decisions.To achieve this, the virtual prototype must provide suitable and comprehensive representations of different data. Furthermore, transformation from one representation to another should proceed formally. Xiang et al. have reviewed the past and current computer-aided design and prototyping tools for fluid power systems. The work revealed that the current tools could not provide a completerepresentation of the design abstractions at the prototyping stage for design judgement. Most of the tools concentrate on the dynamics behaviour. Vital geometrical and product information that relates to the system prototype consideration and evaluation is frequently missing.To advance the development of computer-aided virtual prototyping tools for fluid power systems, there is a need to address the formal representations of different abstractions of behaviour,structural, and product data along with their integration. This paper focuses on these issues and proposes the formalism of a unified component model and the taxonomy based on the feature-based approach. In Section 2, we discuss the feature- based approach focusing on the key information and their representations required for hydraulic system prototyping. Section 3 presents a formalism of the feature-based model and structure for the development of virtual hydraulic system prototypes.The structure is illustrated with an example. Future work and conclusions are given in Section 4.2. Feature-Based ApproachFeatures can be defined as information sets that refer to aspects of attributes that can be used in reasoning about the design, engineering or manufacturing processes. The concept of using features to integrate CAD/CAPP/CAM is not new and there are many papers on the application of this approach in CIM. In all these applications, the feature model is regarded as the basis whereas design by features is the key for the integration. To develop a feature model, the relevant information concerning the design must be identified and grouped into sets based on the nature of the information. The relevant information should contain sufficient knowledge for activities such as design, analysis, test, documentation, inspection, and assembly, as well as support various administrative and logistic functions. Design by features is the process of building a model of the design using features as primitive entities. The feature model provides the standardisation of relevant data. Through the design by features approach, vital knowledge of the design will be generated and stored. Together, the feature model and the design by features approach will provide the essential information, which can be used, not only for the simultaneous consideration of many different concerns with the design, but also to interface the many activities in the design realisation process, including the life cycle support operations. The main drawback of the feature-based design approach is that the feature model should be properly defined . This can be difficult, as features are sets of knowledge that are application dependent. The organisation of the features can also be application specific. Non-trivial data-management problems could arise if the feature model is not properly defined. To avoid these problems, the type,representation and structure of the features should be resolved prior to using the feature-based design methodology. The main concern when developing afeature model is that it is application-specific. In the domain of virtual prototyping of hydraulic systems, the details of the constituent standard components must be able to be used to describe the overall system. The component features are bearers of knowledge about that part. To create a suitable feature model for hydraulic system design based on the assembly of standard components, the relevant information associated with various standard components must be identified and classified. This definition Feature-Based Component Models 667 of the component feature set can then be extended to encompass the subsystem feature set based on the hierarchical structure between the components in the subsystem. In the same manner, a hierarchical structure for the hydraulic system feature representation would evolve by considering the system as a hierarchy of subsystems.The necessary information required for a proper description of the virtual prototype must be no less than that derived by the designer from a physical prototype for decision making. These data should generally include the shape, weight, performance properties, cost, dimensions, functionality data, etc. Comparison with the physical prototyping process, the information required for each standard component could be separated into three distinct groups: behaviour attributes, structural attributes, and product attributes.2.1 Behaviour AttributesThe behaviour of a hydraulic component can be defined in terms of the dynamics characteristics used to satisfy the functional requirements. Consider a hydraulic cylinder connected to a load. Its function is to transmit a force from the stroke of the piston to the load. The maximum force it can transmit can be used to define the functionality and the behaviour requirements can be specified in terms of the desired load acceleration characteristics. Hence for a hydraulic component, behaviour attributes express functionality and can be reflected in the dynamics characteristics. The designer is responsible for the proper definition of the overall system behaviour characteristics in terms of the desired dynamics. A standard component will have its own behaviour and provide a specific plex functions that cannot be achieved by a single standard component are derived using a combination of components. Hence, the behaviour of the standard component will play an important role as the individual behaviours of components together with their arrangement can alter the overall system function .The behaviour of a standard component can be nonlinear and can be dependent on the operating conditions. When two components are combined, it is possible that their behaviours can interact and produce undesired or unintended characteristics. These unwanted behaviours are assumed to have been resolved during the configuration design stage. The hydraulic circuit used in theprototyping stage is assumed to be realisable and without any undesirable interacting behaviours. This means that the output behaviour of a component will provide the input to the subsequent component.The representation of behaviours for hydraulic systems has been widely investigated. These representations include transfer functions, state-space and bond graphs. Transfer functions (for single-input–single-output systems) and state-space equations (for multiple-input–multiple-output systems) are based on the approximation of the dynamics about a nominal operating condition. The power bond graph model is based on the causal effects that describe the energy transformations in the hydraulic system. This approach is appealing for hydraulic system analysis. The main disadvantage is that the derivation of the dynamics equation in a bond graph of a complicated fluid power system can become very tedious. As a result, recent work has concentrated on the used of artificial intelligence to represent the nonlinear mapping between the input and output data, which can be obtained via experimental work. These nonlinear mappings can be accomplished using artificial neural networks .It is quite natural for a hydraulic system designer to use input–output data to describe the behaviour of a hydraulic component. The configuration design of a hydraulic system is often achieved through steps of function decomposition. To design a hydraulic system, the designer often tries to decompose the functions and their requirements down to the component level.译文：基于原型液压系统特征的机构模型摘要：本文为原型液压系统的设计提出了一种基于特征的方法。
液压系统的形式及评价外文翻译
The hydraulic presses system of the form and the evaluationThe hydraulic presses the component to carried out to standardize gradually, the series turn, its specification, species, quantity, functionses all had to raise very greatly, particularly is to adopt the new craft of new technique of electronics technique, servo technique...etc. after, the hydraulic presses the exaltation that the quantity of the system gets to show the highest , it developped the important function in national economy and the military industries.Set out from the different angle, can press the system to the liquid to be divided into the different form.1）Press the circulating way of the oil liquid, the liquid press the system and can is divided into the open type system and shut type systems.The open type system mean that the liquid presses the pump to absorb the oil from the fuel tank, the oil is through various control valve, driving the liquid to press to carry out the component, returning to oil to has been changed to return to fuel tank toward valve again.This kind of system structure is more simple, can develop the fuel tank to spread hot, precipitate the miscellaneous quality function, but often get in touch with with air because of the oil liquid, make air be easy to seep into the system, causing the organization exercise the gravamen steady etc. result.The open type system fuel tank is big, oil pump from absorb the function and like.In the shut type system, the liquid presses the pump of into pipeline directly with performance the component return to pipeline connect with each other, work the liquid carries on closing the circulation in the tube road of the system.Its structure tightly packed, with the air opportunity to get in touch with little, not easy infiltration system of air, so spread to move more steady.The work organization become soon and change to depend to regulate the pump or motors to change to measure the organization realization, avoided the open type system change toward process appear of liquid press the impact and energy losses.But the shut type system more the open type system complications, because of having no fuel tank, the oil liquid spread hot and filter the condition is worse.In order to compensate the leakiness in the system, usually need a small discharge to repair the oil pump and fuel tanks.Because the oil a size of a function of high bar discharge not etc., will make power make use of descend in work process, so the performance component within the shut type system presses the motor for the liquid generally.2）According to system the liquid presses the number of the pump, can is divided into the list pump system, double pump system and pump system more.3）Press the dissimilarity of pump the form with the liquid by, can is divided into the fixed amount pump system and change the quantity pump system.The advantage that changes to measure the pump is to regulate the scope inside, can make use of the power of launch the machine well, but its structure and the manufacturing craft complications, the cost is high, can is divided in to move to change the quantity, control to change the quantity possibly, servo change the quantity, pressure to compensate to change the quantity, press to change the quantity, liquid to press to change to measure various ways of etc..4)Press toward performance the component to provide the dissimilarity of the oil method, can is divided in to establish the system and merge the system.Establish in the system, it is next performance component that previous performance component return to oil of into oil, pass a performance component pressure and will lower once each time.In establish system, the each performance component that be the lord pump toward many roads valve control provides the oil,as long as the liquid presses the exit pressure of the pump enough, the compound of the sport that can carry out each performance component then.But the pressure of the performance component is to fold to add of, so overcome the outside carry ability will with carry out the increment of the component quantity but lower.Merge in the system, be a the pedestal liquid to press the pump toward a performance component to provide the oil, discharge that enters each performance component be just the liquid press the pump exportation discharge of a part.The allotment of the discharge with each last the outside carries the lotus of dissimilarity but variety, enter first outside carry the smaller performance component of lotus, only be each performance component up outside carry the lotus equality, then can carry out to act at the same time.The whole liquid presses to spread the good and bad of move the machine function, mainly being decided by the quality that the liquid presses the system function, including the component quantity good and bad use, basic back track whether fitting etc..The quality of the system function, in addition to satisfying to use the function to request, should make use of, adjust from the efficiency, power that the liquid press the system soon scope and tiny adjust characteristic, vibration and voice of noises and the gearing of the systems and adjust to try whether convenient credibility etc. carry on.The modern engineering machine almost adopts the liquid to press the system, and combine with electronics system, the calculator control technique, the importance that become the modern engineering machine constitutes the part.液压系统的形式及评价液压元件逐步实现了标准化、系列化，其规格、品种、质量、性能都有了很大提高，尤其是采用电子技术、伺服技术等新技术新工艺后，液压系统的质量得到了显著的提高，其在国民经济及军事工业中发挥了重大作用。
DOC-机械专业毕业设计外文翻译--什么是液压-液压系统
DOC-机械专业毕业设计外文翻译--什么是液压-液压系统What is Hydraulic?A complete hydraulic system consists of five parts, namely, power components, the implementation of components, control components, no parts and hydraulic oil. The role of dynamic components of the original motive fluid into mechanical energy to the pressure that the hydraulic system of pumps, it is to power the entire hydraulic system. The structure of the form of hydraulic pump gears are generally pump, vane pump and piston pump. Implementation of components (such as hydraulic cylinders and hydraulic motors) which is the pressure of the liquid can be converted to mechanical energy to drive the load for a straight line reciprocating movement or rotational movement. Control components (that is, the various hydraulic valves) in the hydraulic system to control and regulate the pressure of liquid, flow rate and direction. According to the different control functions, hydraulic valves can be divided into the village of force control valve, flow control valves and directional control valve. Pressure control valves are divided into benefits flow valve (safety valve), pressure relief valve, sequence valve, pressure relays, etc.; flow control valves including throttle, adjusting the valves, flow diversion valve sets, etc.; directional control valve includes a one-way valve , one-way fluid control valve, shuttle valve, valve and so on. Under the control of different ways, can be dividedinto the hydraulic valve control switch valve, control valve and set thevalue of the ratio control valve. Auxiliary components, including fuel tanks, oil filters, tubing and pipe joints, seals, pressure gauge, oil level, such as oildollars. Hydraulic oil in the hydraulic system is the work of the energy transfer medium, there are a variety of mineral oil, emulsion oil hydraulic molding Hop categories.Hydraulic principleIt consists of two cylinders of different sizes and composition of fluid in the fluid full of water or oil. Water is called "hydraulic press"; the said oil-filled "hydraulic machine." Each of the two liquida sliding piston, if the increase in the small piston on the pressure of a certain value, according to Pascal's law, small piston to the pressure of the pressure through the liquid passed to the large piston, pistontop will go a long way to go. Based cross-sectional area of the small piston is S1, plus a small piston in the downward pressure on the F1. Thus, a small piston on the liquid pressure to P = F1/SI, Can be the same size in all directions to the transmission of liquid. "By the large piston is also equivalent to the inevitable pressure P. If the large piston is the cross-sectional area S2, the pressure P on the piston in the upward pressure generated F2 = PxS2Cross-sectional area is a small multiple of the piston cross-sectional area. From the type known to add in a small piston of asmaller force, the piston will be in great force, for which thehydraulic machine used to suppress plywood, oil, extract heavy objects, such as forging steel.History of the development of hydraulicAnd air pressure drive hydraulic fluid as the transmission is made according to the 17th century, Pascal's principle of hydrostatic pressure to drive the development of an emerging technology, the United Kingdom in 1795 Joseph (Joseph Braman ,1749-1814), in London water as a medium to form hydraulic press used in industry, the birth of theworld's first hydraulic press. Media work in 1905 will be replaced byoil-water and further improved.World War I (1914-1918) after the extensive application of hydraulic transmission, especially after 1920, more rapid development. Hydraulic components in the late 19th century about the early 20th century, 20 years, only started to enter the formal phase of industrial production. 1925 Vickers (F. Vikers) the invention of the pressure balanced vane pump, hydraulic components for the modern industrial or hydraulic transmission of the gradual establishment of the foundation. The early 20th century Constantine (G • Constantimsco) fluctuations of the ener gy carried out by passing theoretical and practical research; in 1910 on the hydraulic transmission (hydraulic coupling, hydraulic torque converter, etc.) contributions, so that these two areas of development.The Second World War (1941-1945) period, in the United States 30% of machine tool applications in the hydraulic transmission. It should be noted that the development of hydraulic transmission in Japan thanEurope and the United States and other countries for nearly 20 years later. Before and after in1955, the rapid development of Japan's hydraulic drive, set up in 1956, "Hydraulic Industry." Nearly 20 to 30 years, the development of Japan's fast hydraulic transmission, a world leader.Hydraulic transmission There are many outstanding advantages, it is widely used, such as general workers. Plastic processing industry, machinery, pressure machinery, machine tools, etc.; operating machinery engineering machinery, construction machinery, agricultural machinery, automobiles, etc.; iron and steel industry metallurgical machinery, lifting equipment, such as roller adjustment device; civil waterprojects with flood control the dam gates and devices, bed lifts installations, bridges and other manipulation of institutions; speed turbine power plant installations, nuclear power plants, etc.; ship deck crane (winch), the bow doors, bulkhead valves, such as the sternthruster ; special antenna technology giant with control devices, measurement buoys, movements such as rotating stage; military-industrial control devices used in artillery, ship anti-rolling devices, aircraft simulation, aircraft retractable landing gear and rudder control devices and other devices.什么是液压,一个完整的液压系统由五个部分组成，即动力元件、执行元件、控制元件、无件和液压油。
机械外文翻译文献翻译液压系统1
外文原文：Theory of fluid propertiesWe will concentrate mainly on three fluid properties in this chapter:• The density which leads to mass and hence to hydraulic inertia effects.• The viscosity which leads to the hydraulic friction effects.• The compressi bility and thus the bulk modulus which leads to the hydraulic system stiffness. Notice that the compressibility effect can be modified by air release, cavitation phenomena and by expansion of a pipe, hose or chamber containing the hydraulic fluid.1 Density and compressibility coefficientThe density is the mass of a substance per unit volume:Density has dimensions of [M/L3] and is expressed in kilograms per cubic meter [kg/m3]. As mentioned previously the density is a function of the pressure and the temperature:This function can be approximated by the first three terms of a Taylor series:This can also be expressed as:WithAndThis equation is the linearized state equation for a liquid. Using the definition of thedensity, the two coefficients α and B can also be expressed as:B is known as the isothermal bulk modulus or for simplicity the bulk modulus and α is known as the cubical expansion coefficient. Since fluid density varies with the applied pressure, this implies that a given mass of fluid submitted to a pressure change changes its volume. This phenomenon leads to the definition of the compressibility coefficient β:where β is expressed in units Pa 1 (or m2/N). Considering the relation for a closed hydraulic circuit the mass is constant, and hence:it follows thatUsing the definition of the compressibility coefficient β we obtain:More usually we use the bulk modulus B also known as the volumetric elasticity modulus:The relation between ρ and B implies mass conservation. This relation must be RIGOROUSLY RESPECTED in the calculations. In the modeling and simulation context of fluid energy systems, disregarding the relation between ρ and B leads to abnormal evolutions of pressure in the closed circuit submitted to compression and expansion cycles. This phenomenon is strongly accentuated if aeration occurs in the circuit (when dissolved air in the fluid reappears in the form of bubbles). We shall approach this point by examining the phenomena of aeration and cavitation. The aircan also have adverse consequences on a fluid compressibility. In liquid air can be present in two forms: entrapped and dissolved.Entrapped airWhen the return pipe is not submersed in the tank the liquid jet can entrain some air bubbles in the tank. Another phenomenon that affects the quantity of air in liquid is the leakage.Figure 1: Liquid leakageFigure 2: Air is entrainedThis air stays in the liquid as cavities and can modify the fluid compressibility. In this context we talk about effective bulk modulus. Figure 3 shows the bulk modulus of a diesel fuel at 40 °C with 0, 0.01, 0.1, 1, 10% air. The plot is obtained using the system shown. The model of the diesel fuel properties is based on accurate ex-perimental measurements and are designed for use with injection system which are very fast acting. For this reason air is assumed to be entrained rather than dissolved.Figure 3Dissolved airAir can also be dissolved in a liquid. A certain amount of air molecule can be part of the liquid. In this case the dissolved air does not significantly change the fluid properties.2 Air release and cavitationAir can be dissolved or entrained in liquids and it is possible for air to change from one of these two forms to the other depending on the conditions to which the fluid is subjected.Suppose the fluid is in equilibrium with a certain percentage of dissolved gas (usually air: nitrogen and oxygen). Lowering the pressure above a critical value called the saturation pressure induces aeration. This is the process where the dissolved gas forms air bubbles in the liquid until all the dissolved gases or air are free.The exact point where all the dissolved gas has come out of solution is difficult to pin-point because it depends on the chemical composition and behavior of the gas. This is a non-symmetrical dynamic process: the growing process does not have the same dynamics as when air bubbles disappear. In consequence the total amount of bubbles created when the pressure drops may or may not be redissolved in the liquid when it rises again.If the pressure is dropped further and above another critical value called the vapor pres s ure, the fluid itself starts to vaporize. It corresponds to a liquid phase change. At some point only fluid vapor and gas exist. In liquid systems the term cavitation usually refers to the formation and collapse of cavities in the liquid even if cavities contain air or liquid vapor.To summarize with a sketch what we have introduced see above:Figure 4: Air release and cavitationThe development of a cavity is now recognized as being associated with a nucleation center such as microscopic gas particles, wear or wall asperities. When the liquid is subjected to a tensile stress, cavities do not form as a result of liquid rupture but are caused by the rapid growth of these nuclei.To understand this, think of beer (or champagne if you prefer) in a bottle, when it is closed you see no air bubbles and the liquid does not look fizzy. The pressure in the bottle is above the saturation pressure of the gas in the liquid. When you open the bottle suddenly bubbles appear and so the dissolved gas (molecules of gas held in the liquid) starts to appear as gas.In fact the liquid is gas saturated and the atmospheric pressure is less than the saturation pressure of the liquid. This phenomenon is clearly not cavitation but air release (aeration). Considering nuclei effects, bubbles form only at particular places in your glass: around the glass (due to small asperities) and round any particles present in the liquid. Theoretically, if your liquid was perfectly pure and the wall of the system perfectly regular, air release or cavitation would occur with great difficulty! The key point about cavitation is that it is a phase change: the liquid changes to vapor.A comparison can be made between cavitation and boiling. If we look at the phasediagram below:Figure 5: Cavitation and boilingBoiling is a phase change at constant pressure and variable temperature and cavitation is a phase change at constant temperature and variable pressure.In any system air release starts first and if the pressure decreases further, cavitation may occur. This means that, sometimes, people talk about cavitation when the real phenomenon is air release. Both phenomena can lead to destruction of the material or component.In both cases it is entrained gas that causes the troubles. When cavities encounter high pressure in the downstream circuit, these bubbles or cavities can be unstable and can collapse implosively. The pressure developed at collapse can be large enough to cause severe mechanical damage in the containing vessel. It is well-known that hydraulic pumps and pipework can be badly damaged by cavitaton and air release.In all classical hydraulic systems air release and cavitation must be avoided to prevent material destruction but sometimes it is required like for injection systems to prepare the spray formation.3 ViscosityViscosity is a measure of the resistance of the fluid to flow. This characteristic has both positive and negative effects on fluid power systems. A low viscosity leads to oil leaks in the dead zone formed between the mechanical parts in movement, and a high viscosity will lead to loss of pressure in hydraulic ducts.Viscosity is a characteristic of liquids and gases and is manifested in motion throughinternal damping. Viscosity results from an exchange of momentum by molecular diffusion between two layers of fluid with different velocities. In this sense, the viscosity is a fluid property and not a flow property.Figure 6: ViscosityFigure 6 shows the relation between shearing constraint and difference of flow velocity between two layers .The definition of viscosity was first given by Newton. Between two layers of distance dy, the exerted force between these two layers is given by:where U(y) is the velocity depending on the radial position y and dU/dy the velocity gradient. This proportionality expresses the notion of Newtonian fluid and allows the introduction of μ defined as the dynamic viscosity or the absolute viscosity.The dimension of μ is [ML1-T 1-] and the SI unit is kg/m/s or Pa s. The older unit is the Poise, P, which is 0.1 kg/m/s. However, this is very small and hence the milli Poise, mP, is the common unit which is 10-4 kg/m/s.The dynamic viscosity is the constant of proportionality between a stress and the intensity of shearing between two neighboring layers:However the absolute viscosity is not very often used in fundamental equations. For example the dynamics of the elementary volume between the two layers is expressedas:and thus using the shear stress calculation:In other formulas (e.g. Navier Stokes) the ratio between the absolute viscosity and the density occurs so often that a new parameter called the kinematic viscosity ν is introduced .of dimension [L2T 1-] and so the SI unit is the m2/s. The older unit of kinematic viscosity is the Stoke, St, which is 104-m2/s. However, even this is a very small unit and hence the centistoke cSt is the common unit with 1 cSt = 106-m2/s. This parameter is easily measured with viscometers.Note that the viscosity varies significantly with the fluid temperature.Figure 7: Viscosity against temperatureNormally in absence of air release and cavitation the variation with pressure is not great unless the pressure is very extreme.Figure 8: Variation with pressureViscosity influence on the flowAnother important aspect of the viscosity is its influence on the flow conditions of the fluid. We can distinguish two types of flow conditions:• Laminar flow for which the flow lines are parallel and shearing forces create a pressure drop.• Turbulent flow for which the fluid particles have a disordered, random movement leading to a loss of pressure.These two conditions can be distinguished using the Reynolds number which is defined as follows:WithU: average fluid velocityd: diameter of the duct (hydraulic diameter for others geometries)ρ: densityμ: dynamic viscosityν: kinematic viscosityThe transition between laminar to turbulent flow occurs at the critical Reynolds number. This is not well defined, there exists always a transition region. In a hydraulic line, the critical Reynolds number is generally between 1500 to 2000. For uneven geometries (thin-walled orifices), the critical Reynolds number can be lower than 100. For non-circular cross sections, the hydraulic diameter can be used to determine the Reynolds number. Hydraulic diameter is defined as follows:We now give one example:• Circular orifice of diameter:Flow through orificesOrifices (also called restrictions) can be fixed or variable and occur in huge numbers in fluid systems. Not surprisingly in Engineering courses a mathematical description is presented. This is usually based on Bernoulli’s equation and leads to the formwhere Cq is the flow coefficient. This is variously described as typically 0.7 or varying with orifice geometry and Reynolds number.The second alternative is obviously more correct. If we do take a constant value, we are forced to have the gradient of Q against infinity at the origin! This cannot be and if you try to implement it is a numerical disaster! Clearly the flow is laminar for sufficiently small pressure drops which means that Cq is certainly not constant. One solution is to perform detailed e xperiments and compute Cq against Reynold’s number. In the context of the orifice (not necessarily circular) the Reynold’s number iswhere U is a mean velocity and dh the hydraulic diameter. If we take U=Q/A, we end up with the form Cq =f(Q) and ultimately withIt is possible to work with an implicit relationship like this but we would prefer an explicit formula.This is provided by introducing another dimensionless number known as the flow number and denoted by λ. This is defined asFrom a modelin g point of view λ contains quantities we know. Using λ we haveand provided we have,we have an explicit relationship which is easy to evaluate. There are no more problems to obtain measurements forthan forand so the flow number form has many advantages.References ：[1] McCloy D, Discharge Characteristics of Servo Valve Orifices, 1968 Fluid International Conference.[2] R.C. Binder, “Fluid Mechanics”. 3rd Edition, 3rd Printing. Prentice-Hall, Inc., Englewood Cliffs,NJ. 1956.译文：液压油理论我们将在本章主要讨论液压油的三个特性：•密度（使油液具有质量和液感效应）；•粘性（使油液具有液阻效应）；•可压缩性和体积弹性模量（使油液具有容性效应），值得提醒的是容性效应会受油液中析出的空气、气穴现象和装有油液的的管道、软管或油腔的影响。
液压系统外文文献翻译中英文
外文文献翻译(含：英文原文及中文译文)英文原文Hydraulic systemW Arnold1 IntroductionThe hydraulic station is called a hydraulic pump station and is an independent hydraulic device. It is step by step to supply oil. And control the direction of hydraulic oil flow, pressure and flow, suitable for the host and hydraulic equipment can be separated on the various hydraulic machinery.After the purchase, the user only needs to connect the hydraulic station and the actuator (hydraulic or oil motor) on the mainframe with different tubings. The hydraulic machine can realize various specified actions and working cycles.The hydraulic station is a combination of manifolds, pump units or valve assemblies, electrical boxes, and tank electrical boxes. Each part function is:The pump unit is equipped with a motor and an oil pump, which is the power source of the hydraulic station and can convert mechanical energy into hydraulic oil pressure energy.V alve combination - its plate valve is mounted on the vertical plate, and the rear plate is connected with the same function as the manifold.Oil manifolds - assembled from hydraulic valves and channel bodies. It regulates hydraulic oil pressure, direction and flow.Box--a semi-closed container for plate welding. It is also equipped with an oil screen, an air filter, etc., which is used for cooling and filtering of oil and oil.Electrical box - divided into two types: one is to set the external lead terminal board; one is equipped with a full set of control appliances.The working principle of the hydraulic station: The motor drives the oil pump to rotate, then the pump sucks oil from the oil tank and supplies oil, converts the mechanical energy into hydraulic pressure energy, and the hydraulic oil passes through the manifold (or valve assembly) to adjust the direction, pressure and flow and then passes through the external tube. The way to the hydraulic cylinder or oil motor in the hydraulic machinery, so as to control the direction of the hydraulic motor, the strength of the speed and speed, to promote all kinds of hydraulic machinery to do work.(1) Development history of hydraulic pressureThe development history of hydraulics (including hydraulic power, the same below), pneumatics, and seals industry in China can be roughly divided into three stages, namely: the starting stage in the early 1950s to the early 60s; and the professional in the 60s and 70s. The growth stage of the production system; the 80-90's is a stage of rapid development. Among them, the hydraulic industry began in the early 1950s with thedevelopment of hydraulic machines such as Grinding Machines, broaching machines, and profiling lathes, which were produced by the machine tool industry. The hydraulic components were produced by the hydraulic workshop in the machine tool factory, and were produced for self use. After entering the 1960s, the application of hydraulic technology was gradually promoted from the machine tool to the agricultural machinery and engineering machinery. The original hydraulic workshop attached to the main engine plant was independent and became a professional manufacturer of hydraulic components. In the late 1960s and early 1970s, with the continuous development of mechanization of production, particularly in the provision of highly efficient and automated equipment for the second automobile manufacturing plant, the hydraulic component manufacturing industry witnessed rapid development. The batch of small and medium-sized enterprises also began to become specialized manufacturers of hydraulic parts. In 1968, the annual output of hydraulic components in China was close to 200,000 pieces. In 1973, in the fields of machine tools, agricultural machinery, construction machinery and other industries, the professional factory for the production of hydraulic parts has grown to over 100, and its annual output exceeds 1 million pieces. Such an independent hydraulic component manufacturing industry has taken shape. At this time, the hydraulic product has evolved from the original imitation Su product intoa combination of imported technology and self-designed products. The pressure has been developed towards medium and high pressures, and electro-hydraulic servo valves and systems have been developed. The application of hydraulics has been further expanded. The pneumatic industry started a few years later than hydraulics, and it was only in 1967 that it began to establish a professional pneumatic components factory. Pneumatic components began to be manufactured and sold as commodities. Its sealing industry including rubber seals, flexible graphite seals, and mechanical seals started from the production of common O-rings, oil seals, and other extruded rubber seals and asbestos seal products in the early 1950s. In the early 1960s, it began to develop and produce flexible products. Graphite seals and mechanical seals and other products. In the 1970s, a batch of batches of professional production plants began to be established one after another in the systems of the former Ministry of Combustion, the Ministry of Agriculture, and the Ministry of Agricultural Machinery, formally forming the industry, which laid the foundation for the development of the seal industry.In the 1980s, under the guidance of the national policy of reform and opening up, with the continuous development of the machinery industry, the contradiction between the basic components lags behind the host computer has become increasingly prominent and caused the attention of all relevant departments. To this end, the former Ministry of Machinesestablished the General Infrastructure Industry Bureau in 1982, and unified the original pneumatic, hydraulic, and seal specialties that were scattered in the industries of machine tools, agricultural machinery, and construction machinery, etc. The management of a piece of office, so that the industry in the planning, investment, the introduction of technology and scientific research and development and other aspects of the basic parts of the bureau's guidance and support. This has entered a period of rapid development, it has introduced more than 60 foreign advanced technology, of which more than 40 hydraulic, pneumatic 7, after digestion and absorption and technological transformation, are now mass production, and has become the industry's leading products . In recent years, the industry has intensified its technological transformation. From 1991 to 1998, the total investment of national, local, and corporate self-raised funds totaled about 2 billion yuan, of which more than 1.6 billion were hydraulic. After continuous technological transformation and technological breakthroughs, the technical level of a group of major enterprises has been further improved, and technological equipment has also been greatly improved, laying a good foundation for forming a high starting point, specialization, and mass production. In recent years, under the guidance of the principle of common development of multiple ownership systems in the country, various small and medium-sized enterprises with different ownership have rapidly emerged and haveshown great vitality. With the further opening up of the country, foreign-funded enterprises have developed rapidly, which plays an important role in raising industry standards and expanding exports. So far China has established joint ventures with famous manufacturers in the United States, Germany, Japan and other countries or directly established piston pumps/motors, planetary speed reducers, hydraulic control valves, steering gears, hydraulic systems, hydrostatic transmissions, and hydraulic components. The company has more than 50 manufacturing enterprises such as castings, pneumatic control valves, cylinders, gas processing triplets, rubber seals, and mechanical seals, and has attracted more than 200 million U.S. dollars in foreign capital.(2) Current statusBasic profileAfter more than 40 years of hard work, China's hydraulics, pneumatics and seals industry has formed a complete industrial system with a certain level of production capacity and technical level. According to the statistics of the third n ational industrial census in 1995, China’s state-owned, privately-owned, cooperative, village-run, individual, and “funded enterprises” have annual sales income of more than 1 million yuan in hydraulic, pneumatic, and seal industrial townships and above. There are a total of more than 1,300 companies, including about 700 hydraulics, and about 300 pneumatic and sealing parts. According to thestatistics of the international industry in 1996, the total output value of the hydraulic industry in China was about 2.448 billion yuan, accounting for the 6th in the world; the total output value of the pneumatic industry was about 419 million yuan, accounting for the world’s10 people.2. Current supply and demand profileWith the introduction of technology, independent development and technological transformation, the technical level of the first batch of high-pressure plunger pumps, vane pumps, gear pumps, general hydraulic valves, oil cylinders, oil-free pneumatic components and various types of seals has become remarkable. Improve, and can be stable mass production, provide guarantees for all types of host to improve product quality. In addition, certain achievements have also been made in the aspects of CAD, pollution control, and proportional servo technology for hydraulic pneumatic components and systems, and have been used for production. So far, the hydraulic, pneumatic and seal products have a total of about 3,000 varieties and more than 23,000 specifications. Among them, there are about 1,200 types of hydraulic pressure, more than 10,000 specifications (including 60 types of hydrodynamic products, 500 specifications); about 1350 types of pneumatic, more than 8,000 specifications; there are also 350 types of rubber seals, more than 5000 The specifications are now basically able to adapt to the general needs ofvarious types of mainframe products. The matching rate for major equipment sets can reach more than 60%, and a small amount of exports has started.In 1998, the domestic production of hydraulic components was 4.8 million pieces, with sales of about 2.8 billion yuan (of which mechanical systems accounted for 70%); output of pneumatic components was 3.6 million pieces, and sales were about 550 million yuan (including mechanical systems accounting for about 60%) The production of seals is about 800 million pieces, and the sales volume is about 1 billion yuan (including about 50% of mechanical systems). According to the statistics of the annual report of the China Hydraulic and Pneumatic Sealing Industry Association in 1998, the production and sales rate of hydraulic products was 97.5% (101% of hydraulic power), 95.9% of air pressure, and 98.7% of seal. This fully reflects the basic convergence of production and sales.Although China's hydraulic, pneumatic and sealing industries have made great progress, there are still many gaps compared with the development needs of the mainframe and the world's advanced level, which are mainly reflected in the variety, performance and reliability of products. . Take hydraulic products as an example, the product varieties are only 1/3 of the foreign country, and the life expectancy is 1/2 of that of foreign countries. In order to meet the needs of key hosts, imported hosts, and majortechnical equipment, China has a large number of imported hydraulic, pneumatic, and sealing products every year. According to customs statistics and relevant data analysis, in 1998, the import volume of hydraulic, pneumatic and seal products was about 200 million U.S. dollars, of which the hydraulic pressure was about 140 million U.S. dollars, the pneumatics were 30 million U.S. dollars, and the seal was about 0.3 billion U.S. dollars. The year is slightly lower. In terms of amount, the current domestic market share of imported products is about 30%. In 1998, the total demand for hydraulic parts in the domestic market was about 6 million pieces, and the total sales volume was 4 billion yuan; the total demand for pneumatic parts was about 5 million pieces, and the total sales volume was over 700 million yuan; the total demand for seals was about 1.1 billion yuan. Pieces, total sales of about 1.3 billion yuan. (3) Future developments1. The main factors affecting development(1) The company's product development capability is not strong, and the level and speed of technology development can not fully meet the current needs for advanced mainframe products, major technical equipment and imported equipment and maintenance;(2) Many companies have lagged behind in manufacturing process, equipment level and management level, and their sense of quality is not strong, resulting in low level of product performance, unstable quality,poor reliability, and insufficiency of service, and lack of user satisfaction. And trusted branded products;(3) The degree of professional specialization in the industry is low, the power is scattered, the duplication of the low level is serious, the product convergence between the region and the enterprise leads to blind competition, and the prices are reduced each other, thus the efficiency of the enterprise is reduced, the funds are lacking, and the turnover is difficult. Insufficient investment in development and technological transformation has severely restricted the overall level of the industry and its competitive strength.(4) When the degree of internationalization of the domestic market is increasing, foreign companies have gradually entered the Chinese market to participate in competition, coupled with the rise of domestic private, cooperative, foreign-funded, and individual enterprises, resulting in increasing impact on state-owned enterprises. .2. Development trendWith the continuous deepening of the socialist market economy, the relationship between supply and demand in the hydraulic, pneumatic and sealed products has undergone major changes. The seller market characterized by “shortage” has basically become a buyer’s market characterized by “structured surplus”. Replaced by. From the perspective of overall capacity, it is already in a trend of oversupply, and in particular,general low-grade hydraulic, pneumatic and seals are generally oversupply; and like high-tech products with high technological content and high value and high value-added products that are urgently needed by the host, Can not meet the needs of the market, can only rely on imports. After China's entry into the WTO, its impact may be greater. Therefore, during the “10th Five-Y ear Plan” period, the growth of the industry’s output value must not only rely on the growth of quantity. Instead, it should focus on the structural contradiction of the industry and intensify efforts to adjust the industrial structure and product structure. It should be based on the improvement of quality. Product technology upgrades in order to adapt to and stimulate market demand, and seek greater development.2. Hydraulic application on power slide(1) Introduction of Power Sliding TableUsing the binding force curve diagram and the state space analysis method to analyze and study the sliding effect and the smoothness of the sliding table of the combined machine tool, the dynamics of the hydraulic drive system of the sliding table—the self-regulating back pressure regulating system are established. mathematical model. Through the digital simulation system of the computer, the causes and main influencing factors of the slide impact and the motion instability are analyzed. What kind of conclusions can be drawn from those, if we canreasonably design the structural dimensions of hydraulic cylinders and self-regulating back pressure regulators ——The symbols used in the text are as follows:s 1 - flow source, that is, the flow rate of the governor valve outlet;S el —— sliding friction of the sliding table;R - the equivalent viscous friction coefficient of the slide;I 1 - quality of slides and cylinders;12 - self-adjusting back pressure valve core quality;C 1, c 2 - liquid volume without cylinder chamber and rod chamber;C 2 - Self-adjusting back pressure valve spring compliance;R 1, R2 - Self-adjusting back pressure valve damping orifice fluid resistance;R 9 - Self-adjusting back pressure valve valve fluid resistance;S e2——initial pre-tightening force of self-adjusting back pressure valve spring;I 4, I5 - Equivalent liquid sense of the pipeline;C 5, C 6 - equivalent liquid capacity of the pipeline;R 5, R7 - Equivalent liquid resistance of the pipeline;V 3, V4 - cylinder rodless cavity and rod cavity volume;P 3, P4—pressure of the rodless cavity and rod cavity of the cylinder;F - the slide bears the load;V - speed of slide motion;In this paper, the power bond diagram and the state space splitting method are used to establish the system's motion mathematical model, and the dynamic characteristics of the slide table can be significantly improved.In the normal operation of the combined machine tool, the magnitude of the speed of the slide, its direction and the load changes it undergoes will affect its performance in varying degrees. Especially in the process of work-in-process, the unsteady movement caused by the advancing of the load on the slide table and the cyclical change of the load will affect the surface quality of the workpiece to be machined. In severe cases, the tool will break. According to the requirements of the Dalian Machine Tool Plant, the author used the binding force curve diagram and the state space analysis method to establish a dynamic mathematical model of a self-adjusting back pressure and speed adjustment system for the new hydraulic drive system of the combined machine tool slide. In order to improve the dynamic characteristics of the sliding table, it is necessary to analyze the causes and main influencing factors of the impetus and movement of the sliding table. However, it must pass the computer's digital simulation and the final results obtained from the research.(2) Dynamic Mathematical ModelThe working principle diagram of the self-adjusting back pressure speedregulation system of the combined machine tool slide hydraulic drive system is shown in the figure. This system is used to complete the work-cycle-stop-rewind. When the sliding table is working, the three-position four-way reversing valve is in the illustrated position. The oil supply pressure of the oil pump will remain approximately constant under the effective action of the overflow valve, and the oil flow passes through the reversing valve and adjusts the speed. The valve enters the rodless chamber of the cylinder to push the slide forward. At the same time, the pressurized oil discharged from the rod chamber of the cylinder will flow back to the tank through the self-regulating back pressure valve and the reversing valve. During this process, there was no change in the operating status of both the one-way valve and the relief valve. The complex and nonlinear system of the hydraulic drive system of the self-adjusting back pressure governor system is a kind of self-adjusting back-pressure governor system. To facilitate the study of its dynamic characteristics, a simple and reasonable dynamic mathematical model that only considers the main influencing factors is established. Especially important [1][2]. From the theoretical analysis and the experimental study, we can see that the system process time is much longer than the process time of the speed control valve. When the effective pressure bearing area of the rodless cavity of the fuel tank is large, the flow rate at the outlet of the speed control valve is instantaneous. The overshoot is reflected in thesmall change in speed of the slide motion [2]. In order to further broaden and deeply study the dynamic characteristics of the system so that the research work can be effectively performed on a miniature computer, this article will further simplify the original model [2], assuming that the speed control valve is output during the entire system pass. When the flow is constant, this is considered to be the source of the flow. The schematic diagram of the dynamic model structure of this system is shown in Fig. 2. It consists of a cylinder, a sliding table, a self-adjusting back pressure valve, and a connecting pipe.The power bond graph is a power flow graph. It is based on the transmission mode of the system energy, based on the actual structure, and uses the centralized parameters to represent the role of the subsystems abstractly as a resistive element R, a perceptual element I, and a capacitive element. Three kinds of role of C. Using this method, the physical concept of modeling is clear, and combined with the state-space analysis method, the linear system can be described and analyzed more accurately. This method is an effective method to study the dynamic characteristics of complex nonlinear systems in the time domain. According to the main characteristics of each component of the self-adjusting back pressure control system and the modeling rules [1], the power bond diagram of the system is obtained. The upper half of each key in the figure represents the power flow. The two variables that makeup the power are the force variables (oil pressure P and force F) and the flow variables (flow q and velocity v). The O node indicates that the system is connected in parallel, and the force variables on each key are equal and the sum of the flow variables is zero; 1 The nodes represent the series connection in the system, the flow variables on each key are equal and the sum of the force variables is Zero. TF denotes a transformer between different energy forms. The TF subscripted letter represents the conversion ratio of the flow variable or the force variable. The short bar on the key indicates the causal relationship between the two variables on the key. The full arrow indicates the control relationship. There are integral or differential relationships between the force and flow variables of the capacitive and perceptual elements in the three types of action elements. Therefore, a complex nonlinear equation of state with nine state variables can be derived from Fig. 3 . In this paper, the research on the dynamic characteristics of the sliding table starts from the two aspects of the slide's hedging and the smoothness of the motion. The fourth-order fixed-length Runge-Kutta is used for digital simulation on the IBM-PC microcomputer.(3) Slide advanceThe swaying phenomenon of the slide table is caused by the sudden disappearance of the load acting on the slide table (such as drilling work conditions). In this process, the table load F, the moving speed V, and thepressure in the two chambers of the cylinder P3 and P4 can be seen from the simulation results in Fig. 4. When the sliding table moves at a uniform speed under the load, the oil pressure in the rodless cavity of the oil cylinder is high, and a large amount of energy is accumulated in the oil. When the load suddenly disappears, the oil pressure of the cavity is rapidly reduced, and the oil is rapidly reduced. When the high-pressure state is transferred to the low-pressure state, a lot of energy is released to the system, resulting in a high-speed forward impact of the slide. However, the front slide of the sliding table causes the pressure in the rod cavity of the oil cylinder to cause the back pressure to rise, thereby consuming part of the energy in the system, which has a certain effect on the kicking of the slide table. We should see that in the studied system, the inlet pressure of the self-adjusting back pressure valve is subject to the comprehensive effect of the two-chamber oil pressure of the oil cylinder. When the load suddenly disappears, the pressure of the self-adjusting back pressure valve rapidly rises and stably exceeds the initial back pressure value. It can be seen from the figure that self-adjusting back pressure in the speed control system when the load disappears, the back pressure of the cylinder rises more than the traditional speed control system, so the oil in the rod cavity of the cylinder absorbs more energy, resulting in the amount of forward momentum of the slide It will be about 20% smaller than traditionalspeed control systems. It can be seen from this that the use of self-adjusting back-gear speed control system as a drive system slider has good characteristics in suppressing the forward punch, in which the self-adjusting back pressure valve plays a very large role.(4) The smoothness of the slideWhen the load acting on the slide changes periodically (such as in the case of milling), the speed of the slide will have to fluctuate. In order to ensure the processing quality requirements, it must reduce its speed fluctuation range as much as possible. From the perspective of the convenience of the discussion of the problem, assume that the load changes according to a sine wave law, and the resulting digital simulation results are shown in Figure 5. From this we can see that this system has the same variation rules and very close numerical values as the conventional speed control system. The reason is that when the change of the load is not large, the pressure in the two chambers of the fuel tank will not have a large change, which will eventually lead to the self-regulating back pressure valve not showing its effect clearly.(5) Improvement measuresThe results of the research show that the dynamic performance of a sliding table with self-regulating back pressure control system as a drive system is better than that of a traditional speed control system. To reduce the amount of kick in the slide, it is necessary to rapidly increase the backpressure of the rod cavity when the load disappears. To increase the smoothness of the sliding table, it is necessary to increase the rigidity of the system. The main measure is to reduce the volume of oil. From the system structure, it is known that the cylinder has a large volume between the rod cavity and the oil discharge pipe, as shown in Fig. 6a. Its existence in terms of delay and attenuation of the self-regulating back pressure valve function, on the other hand, also reduces the rigidity of the system, it will limit the further improvement of the propulsion characteristics and the smoothness of the motion. Thus, improving the dynamic characteristics of the sliding table can be handled by two methods: changing the cylinder volume or changing the size of the self-regulating back pressure valve. Through the simulation calculation of the structural parameters of the system and the comparison of the results, it can be concluded that the ratio of the volume V4 between the rod cavity and the oil discharge pipe to the volume V3 between the rodless cavity and the oil inlet pipe is changed from 5.5 to 5.5. At 1 oclock, as shown in the figure, the diameter of the bottom end of the self-adjusting back pressure valve is increased from the original 10mm to 13mm, and the length of the damper triangle groove is reduced from the original lmm to 0.7mm, which will enable the front of the slide table. The impulse is reduced by 30%, the transition time is obviously shortened, and the smoothness of the slide motion will also be greatly improved.中文译文液压系统W Arnold1. 绪论液压站称液压泵站,是独立的液压装置。
常用的液压系统的动力源是泵和蓄能器外文文献翻译、中英文翻译、外文翻译
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 pumpinlet . 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 radius to 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 in pump 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 , the cylinder 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 a relief 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 axhievetheir 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 the cam-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。
液压相关英语翻译
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
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
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
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
液压系统构成中英文对照外文翻译文献
(文档含英文原文和中文翻译)中英文资料对照外文翻译The hydraulic system constitutionhydraulic system composition department wind and the function, widely is applying on each kind of mechanical device the hydraulic system, the use has the continual fluid fat liquor now, actuates through the hydraulic pump the hydraulic pump the electric motor or the engine mechanical energy transforms the fat liquor the pressure energy, passes through each kind of control valve, delivers took the actuator in the hydraulic cylinder motor, transforms again while the mechanical power actuates the load. Constitutes such hydraulic system each constituent and the function. The hydraulic system characteristic and the use hydraulic pressure took one transmission technology, has its prominent merit:Can produce the very big power, moreover controls easily; May use the pump to obtain very the high pressure (20-30MPa) hydraulic fluid very easily, sends in this pressure oil the hydraulic cylinder then to produce the very big strength; Can in the very wide scope the limitless speed change; To altogether gives the oil motor or the hydraulic cylinder current capacity with the control valve carries on the stepless adjustment, then at will controls its revolving or the translation speed; Very easy to prevent the overload, the security is big; The size slightly strives in a big way, installs the position to be possible the free choice; Output strength adjustment simple accurate, but long-distance control.Hydraulic system use and service, in order to guarantee the mechanical device non-breakdown the work, must follow the factory the use service request.The hydraulic system is infinitely varied, took the different machinery a constituent, its use matters needing attentionalso differ from naturally.The hydraulic system uses and services the duty including the debugging, the inspection, the service and the repair. How debugs? The debugging is causes the new equipment to put the operation or to cause the original equipment to put the operation a series of activities, including the installment, the oil injection, the flushing, the adjustment, runs gathers. The inspection is examined system active status and function is whether correct, including the observation, the survey and tries to move.The maintenance is refers to the guarantee system the normal function, the few attrition and the replacement wearing parts, including the cleaning up and the replacement components, namely trades the oil, trades ponders the core, trades the seal.The repair is system reply function a series of activities which causes to crash.First must according to the breakdown phenomenon determine expires the spot and verifies the expiration reason, this is the so-called breakdown diagnosis. Then the replacement expiration part, makes the mechanical device to restore the work, this named repair.The expiration part should return the plant to repair.Time use service matters needing attention: When security, use and service hydraulic system, when most important question pays attention to the security, for guarantees the security, has the pressure when the system does not have to loosen the pipe connection, the screw joint or the part.Certainly must put first down the load, causes the pump engine off and releases the accumulator the pressure oil, then opens the thing again, does not have the oil used to work. Although many practical security taboo into general knowledge, but the attention often concentrates in the breakdown phenomenon, but neglects the latent danger.Therefore, in starts to repair the system reason this implementation standardization the engine off procedure, after the repair draws up invests the movement, should implement standardized the again start procedure:Engine off procedure it including following several aspects:1. Puts the low suspension the load or carries on the machinery supports and protections to it.2. Release system3. In release accumulator pressure oil4. Release pressure intensifier both sides pressure oil5. Cut-off electricity control system6.DumpStarts the procedure including following several aspects:1. Elimination expiration root2. If the component failure or the replacement period pollutant enters the system, then according to needs to clean up or the flushing system3. Confirms the part correctly unmistakable4. Confirms the hydraulic pressure connection correctly unmistakable5. Confirms the electrical connection correctly unmistakable6. Adjustable part to secure state7. Fills the oil for the pump and the motor shell8. According to needs to refuel to the system and to deflate9. Relieves the secure interconnection to protect10. Calls the alarm bell and the notice all presents the personnel soon to restart11.Starting systemThe item which this is carries on when service must pay attention, in regarding its sanitary, when service also must pay attention, when service hydraulic system, must do utmost the attention absolutely clean Arab League condition, because the pollutant is the hydraulic system most dangerous enemy.Does not have to carry on the polish and the welding work in the service hydraulic system scene. Loosens in front of the thread must its outside clean first cleanly.With clean returns to protects changes passes over the system the interior to use to open the mouth to seal, guards against the pollutant to enter thesystem.Cleans up when the fuel tank does not permit the use cotton and kapok silk and the rags.Must pass through the filter to the system oil injection.In the tubing, refuels with the flushing is the maintenance clean important link, its matters needing attention are as follows:1. The tubing pipe or the hose damage when must replace immediately.When chooses the pipe, the hose, the screw connector or the flange, must guarantee the pressure rated value (i.e. wall thickness, material quality and so on) satisfy the operation requirements.The hard tube must use the seamless steel pipe.The steel pipe and the metal pipe connection must clean absolutely before the installment, does not have the oil dirt, to scale, the welding, the scrap and so on.May use the steel wire brush, the tube cleaner to clean up or the acid pickling.In front of the acid pickling pipe must carry on degreasing processing, after the acid pickling must clean thoroughly. After cutting in the pipe bank or ridge between fields should the articulation awl hole, remove the burr which possibly has, but cannot ream excessively in order to avoid sells the weak connection.After assembly the pipe does not have again to weld or the gas welding, because is unable to clean up.The hose should the curved several times in order to release any detention the dirty thing.In front of the elbow piece the tubing wants the annealing, prevented when elbow piece the corrugation or changes flat.Wants the accurate elbow piece, enable the pipe then not to arrive after the elastic deformation. The flange must in the fitting surface coordinate smoothly before, and with the length suitable bolt fastening, whether there is the screw connector does install should inspect in the thread the metal burr, in the straight thread does not permit the use seal bandage.If the drive pipe must deposit period of time, should stop up the orifice to prevent the foreign matter enters.But does not have to use the rags or other moves the capital to stop up the orifice, because this only can bring the contamination concern, should use the size appropriate seal cap.2. Refuels the oil drum to want horizontal-type depositing, as far as possible deposits in the room or the awning, opens in front of the oil tung, cleans the barrel to go against and the bung thoroughly, prevented the soil and other outside pollutant enter the fat liquor.Only with the clean vessel, the hose and so on transports the fat liquor from the oil drum to the fuel tank.The recommendation with has at least in the 25um filter feeding pump. Provides 200 goals in the fuel tank oiling tube to ponder the net.The filter is actually specially for the system need oil fluid variety use.Sometimes also discovers the pollutant in the new fat liquor, therefore should for work through the portable purifier the hydraulic system tops up. When portable purifier hose involvement fuel tank, should use cloth attachment cleaning which clean does not shed hair to be clean, prevented the soil and other impurities enter the system.3.Before flushing flushing should take down the precise system part, but installs the pipe nipple in its position or hollow.From the main pipeline which flushes is dismantled the system to ponder the core.The flushing current capacity should for the system anticipated current capacity 2-2.5 times.If possible, use heat flush fluid (85℃).Each time only flushes a leg, from most approaches the wash out pump the return route start, to the downstream advancement, this possibly must additionally build in turn in the system up to the valve, realizes this kind of plan. Cannot use the system pump to take the wash out pump.Generally speaking, the power type pump like centrifugal pump and so on may provide the enough flood peak and the great current capacity, the movement quite is economical, and to flushes the period circulation the pollutant to have the good es the capacity in the flushing system with to use the flushing filter which the current capacity matches, the filtration precision to be as far as possible high, does not have to be lower than the recommendation system filtration precision. If has the possibility, uses the assistance to flush the fuel tank to avoid the pollutant being detained in the system fuel tank.The establishment fat liquor sample plan inspects dustiness, thus determined when finished the flushing procedure.After flushing, takes all measures to prevent when rewiring work part leads the pollutant.4.The replacement part part model must correct unmistakable.When if cannot find the similar model the part to have to use the similar part substitutes, must pay attention to the function, the parameter, the connection size is whether consistent, but also must pay attention installs the position, the ambient temperature, the working voltage and so on.The old seal packing collar must replace, does not permit two uses.The bolt and the screw connector must even screw tight the big stipulation the torque, prevents the part distortion influence work. The adjustable part like delivery valve, the flow valve, the variable displacement pump and so on must establish.5.When accumulator accumulator pressure vessel, Asia locality related safety rule compulsory control.In is loaded with on the accumulator hydraulic system carries on in front of any work, must first download the system pressure.The accumulator shell does not permit the welding and the processing, does not repair when possibly causes the serious accident, therefore must have to repair the accumulator returns delivers the plant to carry on the repair.Hydraulic pump selection: The hydraulic pump is the hydraulic system power supply.Must select can adapt the pressure which the actuator requests to have the return route pump, simultaneously must consider fully the reliability, the life Maintainability one side and so on elect the pump can plant the long-term movement in the system.The hydraulic pump type are extremely many, its characteristic also has the very big difference. Chooses when the hydraulic pump must consider the factor has working pressure, current capacity, rotational speed, quota or variable, variable way, volumetric efficiency, overall effectiveness index, the prime mover type, the noise, the pressure oscillation rate, self-absorption ability and so on, but also must consider and the hydraulic fluid compatibility, the size, the weight, the economy, Maintainability, these factors.The hydraulic pump discharge pressure should be the actuator needs the pressure, the tubing pressure loses, the control valve sum of pressure loss, it does not have to surpass in the sample the rated pressure, when the emphasis security, the reliability.Also should leave leeway the big leeway.In when sample highest working pressure when short-term impact permits pressure.If each circulation plants all has the impact pressure, the pump life can reduce obviously, even the pump can damage.Hydraulic pump life: The hydraulic pump is the hydraulic system power part, its function is transforms the prime mover mechanical energy the liquid the pressure energy, refers to in the hydraulic system the oil pump, it provides the power to the entire hydraulic system.Hydraulic pump structural style common toothed wheel pump, vane pump and ram pump. Affects the hydraulic pump the service life factor to be very many, except outside pump own design, manufacture factor and some with pump use Guanyuan (for example shaft coupling, oil filter and so on) selects, in the test run movement process operation and so on also concerns.1.The air compressorselects the air compressor the basis is the working pressure and the current capacity which the pneumatic system needs.At present, the pneumatic system commonly used working pressure is 0.5~0.8MPa, may select the rated pressure is directly the 0.7~1MPa low-pressure air compressor, the special need fluid may select, high-pressured or the ultrahigh voltage air compressor. When determination air compressor air displacement, should satisfy the biggest gas consumption which each air operated equipment needs (to be supposed to transform into free air gas consumption) the sum.(1) was mad the source refining equipmentgeneral use the air compressor all uses the oil lubrication, the air is compressed in the air compressor, the temperature may elevate 140~170℃, by now were partial the lubricating oil to turn the gas, mixed in the compressed air, in addition in the air water and the dust, formed included mix impurity and so on the water vapor, oil gas, dust compressed air.Ifprovides this kind of compressed air to the air operated equipment use, will be able to have following adverse consequences:Gathers in the compressed air the oil gas to gather in the gas storage fills forms the combustible, even has the detonation danger; Simultaneously the oil vaporizes after the high temperature forms the organic acid, causes the hardware to corrode, affects the equipment the life.(2)The mix impurity deposition in the pipeline and the air operated part, causes to pass flows the area to reduce, circulation drag increment, the overall system work is unstable, when serious, system knock off.(3)In the compressed air water vapor can congeal the waterdrop under certain pressure and the temperature, can cause the pipeline and the assistance part in the cold season because of freezes destroys.(4)In the compressed air dust has the abrasive action to the air operated part movement part, causes it attrition to be serious, affects their life.Thus it can be seen, establishes in the pneumatic system eliminates the water, eliminates the oil, the dust removal and dry and so on was mad the source refining equipment is extremely essential.Second, the air operated assistance partair operated part interior has many relative slippers, somewhat relative slipper depends on the seal packing collar to seal.In order to reduce transports the moving parts relatively the friction force, guaranteed the part movement is normal; In order to reduce the packing material the attrition, prevents divulging; In order to prevent the pipeline and the metal part corrosion, lengthens the part service life, guaranteed the good lubrication is extremely important.The lubrication may not divide into and spurts the mist lubrication for the oil lubrication.Some many air operated application domain does not allow to spurt the mist lubrication.If food and the drugs packing, in the transportation process, the oil granule returns to pollution food and the drugs; The oil granule can affect certain raw material for industry, the chemicals nature; The oil mist can affect the high-level spray coating surface and the electronic component surface quality; The oil mist can affect the measuring instrument true the survey; The oil mist can harm the human body health and so on.Therefore at present uses the mist lubrication to reduce gradually, does not give the oil lubrication already very popularly.Still did not use the rubber material for the oil lubrication to take the glide spot the seal, but sealed has the detention tank special structure, in order to memory lubricant.Other components should use not the easy rusty metal material or the nonmetallic material.For the oil lubrication part also may not to the oil use, once but gives the oil, does not have the midway to stop feed.At the same time, must prevent the condensed water enters in the part, in order to avoid flushes the lubricant.Not only has not saved the lubricating utensils and the lubricating oil for the oil lubrication part, improved the working conditions, moreover reduced the maintenance work load, reduced the cost.Moreover, also improved the lubrication condition.Its lubrication effect with the transit discharge, the pressure height, the tubing condition and so on all has nothing to do with.Also does not exist forgot refuels creates the breakdown the matter.The mist lubrication part has the oil mist and the centralism lubrication part two kinds.In (1) pneumatic system each kind of air valve, the air cylinder, the gas motor and so on, its movable part all needs to lubricate, but take the compressed air all seals the air chamber as the power air operated part, cannot use the general method oil injection, only can mix in by some method the oil in the air current, the belt to the place which needs to lubricate.The oil mist is this kind of kind of special oil injection installment.After it causes the lubrication oilatomization to pour into in the air current, enters the part along with the air which needs to lubricate. Refuels with this method, has the lubrication to be even, to be stable, the oil consumption few and does not need characteristics and so on big oil storage equipment.(2) air strainer is in the pneumatic system important link, is further filters the dust compressed air the impurity.The filter form are very many, the commonly used type includes: The disposable filter and two filter, have been requesting the high special occasion, may use the highly effective filter.99. In the pneumatic actuator system, called generally the filter, the oil mist, the pressure relief valve for air operated three association (or three big-ticket items), are in the pneumatic system the essential auxiliary unit.(3) silencerpneumatic circuit and the hydraulic pressure return route are different, it does not suppose the exhaust pipeline generally, after the compressed air use the direct platoon person atmosphere, because the gas rapidly inflation and forms the turbulent flow phenomenon, will have the intense exhaust noise.The exhaust speed and the power are bigger, the exhaust noise is bigger, may generally big 100~200dB.The noise harms people's physical and moral integrity directly, must eliminate or weaken.For the noise reduction, generally often installs the silencer in the pneumatic system air vent.The air operated functional elementair operated functional element is transforms in the pneumatic system the compressed air pressure energy the mechanical energy the part.It including air cylinder friendly motor.The air cylinder uses in realizing the straight reciprocating motion or swinging, was mad the motor uses in realizing the continual gyroscopic motion.First, The air cylinderair cylinder is in the pneumatic system the most commonly used one kind of functional element, compares with the hydraulic cylinder, it has the structure simply, pollutes, the movement few keen, responded quick, easy to make, easily to service, the cost low status merit, but because the thrust force is small, widely uses in the underloading system.(1) The air cylinder classifiedbasis air cylinder exploitation conditions are different, its structure, the shape, the type are very many, below introduces several kind of classifications.May divide into according to the compressed air function in the piston end surface direction: List function air cylinder and double-acting air cylinder.(2)Different may divide into according to the structure characteristic: Plunger-type air cylinder, plunger air cylinder, film air cylinder, leaf blade type oscillating cylinder, gear strip type oscillating cylinder and so on.(3) May divide into according to the air cylinder function: Ordinary air cylinder and special air cylinder.The ordinary air cylinder refers to the general plunger-type air cylinder, uses in the not special request the situation.The special air cylinder uses in having the special request situation, like was mad - - the fluid damping cylinder, the film air cylinder, flush are mad the air cylinder, the expansion and contraction air cylinder and so on.(4) According to installs the way differently to be possible to divide into: The ear place type, the flange type, sell the shaft type and the flange type and so on.(二)Common air cylinder principle of work and applicationThe ordinary air cylinder principle of work and the use are similar to the hydraulic cylinder, here no longer give unnecessary detail, below only introduces the special air cylinder.1. Is mad - - the fluid damping cylinderbecause the ordinary air cylinder works time, the compressed gas condensibility is big, when the outside work load change is big, the air cylinder appears “crawling” or “self-propelled” the phenomenon, the stability When therefore the equip ment precision is high, the air cylinder work stable request is also high, often uses was mad - - the fluiddamping cylinder is becomes by the air cylinder and the hydraulic cylinder combination, take the compressed air as an energy, by the hydraulic fluid took the control adjustment air cylinder velocity of movement the medium, the use liquid incompressibility control liquid displacement, adjusts the piston the velocity of movement, obtains the piston the steady motion.2. The film air cylinderfilm type air cylinder is replaces the piston by the thin film the air cylinder.It mainly by the cylinder body, the diaphragm, the diaphragm capsule and the connecting rod and so on the major parts is composed.Has the list to affect the type and the double-acting type.液压系统的构成液压系统的组成部风及其作用，如今在各种机械设备上广泛应用着的液压系统,使用具有连续流动性的油液,通过液压泵把驱动液压泵的电动机或发动机的机械能转换成油液的压力能,经过各种控制阀,送到作为执行器的液压缸马达中,再转换乘机械动力去驱动负载.构成这样的液压系统的各个组成部分及其作用.液压系统的特点和用途液压作为一种传动技术,有其突出的优点:能产生很大的动力,而且控制容易；可以用泵很容易地得到很高压力(20-30MPa)的液压油,把此压力油送入液压缸即可产生很大的力；能在很宽范围内无极变速；用控制阀对共给液压马达或液压缸的流量进行无级调整,即可随意控制其旋转或直线运动的速度；很容易防止过载,安全性大；尺寸小出力大,安装位置可自由选择；输出力的调整简单准确,可远程控制.液压系统的使用与维修，为了保证机械设备无故障的工作，必须遵循制造厂的使用维修要求。
- 1、下载文档前请自行甄别文档内容的完整性，平台不提供额外的编辑、内容补充、找答案等附加服务。
- 2、"仅部分预览"的文档,不可在线预览部分如存在完整性等问题,可反馈申请退款(可完整预览的文档不适用该条件!)。
- 3、如文档侵犯您的权益，请联系客服反馈,我们会尽快为您处理(人工客服工作时间：9:00-18:30)。
外文资料译文液压系统绪论液压站又称液压泵站，是独立的液压装置。
它按逐级要求供油。
并控制液压油流的方向、压力和流量，适用于主机与液压装置可分离的各种液压机械上。
用户购后只要将液压站与主机上的执行机构（油缸或油马达）用油管相连，液压机械即可实现各种规定的动作和工作循环。
液压站是由泵装置、集成块或阀组合、油箱、电气盒组合而成。
各部件功能为：泵装置－－上装有电机和油泵，是液压站的动力源，将机械能转化为液压油的压力能。
集成块－－由液压阀及通道体组装而成。
对液压油实行方向、压力和流量调节。
阀组合－－板式阀装在立板上，板后管连接，与集成块功能相同。
油箱－－板焊的半封闭容器，上还装有滤油网、空气滤清器等，用来储油、油的冷却及过滤。
电气盒－－分两种型式。
一种设置外接引线的端子板；一种配置了全套控制电器。
液压站的工作原理：电机带动油泵转动，泵从油箱中吸油供油，将机械能转化为液压站的压力能，液压油通过集成块（或阀组合）实现了方向、压力、流量调节后经外接管路并至液压机械的油缸或油马达中，从而控制液动机方向的变换、力量的大小及速度的快慢，推动各种液压机械做功。
1.1发展历程我国液压（含液力，下同）、气动和密封件工业发展历程，大致可分为三个阶段，即：20世纪50年代初到60年代初为起步阶段；60~70年代为专业化生产体系成长阶段；80~90年代为快速发展阶段。
其中，液压工业于50年代初从机床行业生产仿苏的磨床、拉床、仿形车床等液压传动起步，液压元件由机床厂的液压车间生产，自产自用。
进入60年代后，液压技术的应用从机床逐渐推广到农业机械和工程机械等领域，原来附属于主机厂的液压车间有的独立出来，成为液压件专业生产厂。
到了60年代末、70年代初，随着生产机械化的发展，特别是在为第二汽车制造厂等提供高效、自动化设备的带动下，液压元件制造业出现了迅速发展的局面，一批中小企业也成为液压件专业制造厂。
1968年中国液压元件年产量已接近20万件；1973年在机床、农机、工程机械等行业，生产液压件的专业厂已发展到100余家，年产量超过100万件，一个独立的液压件制造业已初步形成。
这时，液压件产品已从仿苏产品发展为引进技术与自行设计相结合的产品，压力向中、高压发展，并开发了电液伺服阀及系统，液压应用领域进一步扩大。
气动工业的起步比液压稍晚几年，到1967年开始建立气动元件专业厂，气动元件才作为商品生产和销售。
含橡塑密封、机械密封和柔性石墨密封的密封件工业，50年代初从生产普通O型圈、油封等挤压橡塑密封和石棉密封制品起步，到60年代初，开始研制生产机械密封和柔性石墨密封等制品。
70年代，在原燃化部、一机部、农机部所属系统内，一批专业生产厂相继成立，并正式形成行业，为密封件工业的发展成长奠定了基础。
进入80年代，在国家改革开放的方针指引下，随着机械工业的发展，基础件滞后于主机的矛盾日益突出，并引起各有关部门的重视。
为此，原一机部于1982年组建了通用基础件工业局，将原有分散在机床、农业机械、工程机械等行业归口的液压、气动和密封件专业厂，统一划归通用基础件局管理，从而使该行业在规划、投资、引进技术和科研开发等方面得到基础件局的指导和支持。
从此进入了快速发展期，先后引进了60余项国外先进技术，其中液压40余项、气动7项，经消化吸收和技术改造，现均已批量生产，并成为行业的主导产品。
近年来，行业加大了技术改造力度，1991~1998年国家、地方和企业自筹资金总投入共约20多亿元，其中液压16亿多元。
经过技术改造和技术攻关，一批主要企业技术水平进一步提高，工艺装备得到很大改善，为形成高起点、专业化、批量生产打下了良好基础。
近几年，在国家多种所有制共同发展的方针指引下，不同所有制的中小企业迅猛崛起，呈现出勃勃生机。
随着国家进一步开放，三资企业迅速发展，对提高行业水平和扩大出口起着重要作用。
目前我国已和美国、日本、德国等国著名厂商合资或由外国厂商独资建立了柱塞泵/马达、行星减速机、转向器、液压控制阀、液压系统、静液压传动装置、液压件铸造、气动控制阀、气缸、气源处理三联件、机械密封、橡塑密封等类产品生产企业50多家，引进外资2亿多美元。
1.2目前状况1.21基本概况经过40多年的努力，我国液压、气动和密封件行业已形成了一个门类比较齐全，有一定生产能力和技术水平的工业体系。
据1995年全国第三次工业普查统计，我国液压、气动和密封件工业乡及乡以上年销售收入在100万元以上的国营、村办、私营、合作经营、个体、“三资”等企业共有1300余家，其中液压约700家，气动和密封件各约300余家。
按1996年国际同行业统计，我国液压行业总产值23.48亿元，占世界第6位；气动行业总产值4.19亿元，占世界第10位。
在软件设计采用模块化设计，不同的液压保护装置用在不同的矿中，这使高性能控制器的软件存在很大的差异。
1.22当前供需状况通过技术引进，自主开发和技术改造，高压柱塞泵、齿轮泵、叶片泵、通用液压阀门、油缸、无油润滑气动件和各类密封件第一大批产品的技术水平有了明显的提高，并可稳定的批量生产，为各类主机提高产品水平提供了保证。
另外，在液压气动元件和系统的CAD、污染控制、比例伺服技术等方面也取得一定成果，并已用于生产。
目前，液压、气动和密封件产品总计约有3000个品种、23000多个规格。
其中，液压有1200个品种、10000多个规格（含液力产品60个品种、500个规格）；气动有1350个品种、8000多个规格；橡塑密封有350个品种、5000多个规格，已基本能适应各类主机产品的一般需要，为重大成套装备的品种配套率也可达60%以上，并开始有少量出口。
1998年国产液压件产量480万件，销售额约28亿元（其中机械系统约占70%）；气动件产量360万件，销售额约5.5亿元（其中机械系统约占60%）；密封件产量约8亿件，销售额约10亿元（其中机械系统约占50%）。
据中国液压气动密封件工业协会1998年年报统计，液压产品产销率为97 .5%（液力为101%），气动为95.9%，密封为98.7%。
这充分反映了产销基本衔接。
我国液压、气动和密封工业虽取得了很大的进步，但与主机发展需求，以及和世界先进水平相比，还存在不少差距，主要反映在产品品种、性能和可靠性等方面。
以液压产品为例，产品品种只有国外的1/3，寿命为国外的1/2。
为了满足重点主机、进口主机以及重大技术装备的需要，每年都有大量的液压、气动和密封产品进口。
据海关统计及有关资料分析，1998年液压、气动和密封件产品的进口额约2亿美元，其中液压约1.4亿美元，气动近0.3亿美元，密封约0.3亿美元，比1997年稍有下降。
按金额计，目前进口产品的国内市场占有率约为30%。
1998年国内市场液压件需求总量约600万件，销售总额近40亿元；气动件需求总量约500万件，销售总额7亿多元；密封件需求总量约11亿件，销售总额约13亿元。
现场总线的使用上，在德国的EEP公司采用现场总线技术实现信息的传递，而MARCO公司使用自定义格式收集器技术。
开放集电极技术。
目前，在国内运用成熟和广泛的的CAN总线技术是德国BOTCH公司提出的。
在实际系统中控制器之间的通信是由双RS422传递大量数据实现的。
现场总线地下工作时需要特殊处理。
由于本质安全要求的考虑，电源的电量应受到严格控制。
通常每个电源只能提供五或六个控制器，电磁先导阀的电量。
因此，这个系统需要大量的独立电源。
为了为了避免电流不平衡导致破坏原有的安全性，控制器之间的数据信号需通过信号隔离器，可以实现电气信息的通断连接。
1.3今后发展走势1.31影响发展的主要因素(1)企业产品开发能力不强，技术开发的水平和速度不能完全满足先进主机产品、重大技术装备和进口设备的配套和维修需要；(2)不少企业的制造工艺、装备水平和管理水平都较落后，加上质量意识不强，导致产品性能水平低、质量不稳定、可靠性差，服务不及时，缺乏使用户满意和信赖的名牌产品；(3)行业内生产专业化程度低，力量分散，低水平重复严重，地区和企业之间产品趋同，盲目竞争，相互压价，使企业效益下降，资金缺乏、周转困难，产品开发和技术改造投入不足，严重地制约了行业整体水平的提高以及竞争实力的增强；(4)国内市场国际化程度日益提高，国外公司纷纷进入中国市场参与竞争，加上国内私营、合作经营、个体、三资等企业的崛起，给国有企业造成愈来愈大的冲击。
1.32发展走势随着社会主义市场经济的不断深化，液压、气动和密封产品的市场供求关系发生较大变化，长期来以“短缺”为特征的卖方市场已基本成为以“结构性过剩”为特征的买方市场所取代。
从总体能力看，已处于供大于求的态势，特别是一般低档次液压、气动和密封件，普遍供过于求；而主机急需的技术含量高的高参数、高附加值的高档产品，又不能满足市场需要，只能依赖于进口。
在我国加入WTO后，其冲击有可能更大。
因此，“十五”期间行业产值的增长，决不能依赖于量的增长，而应针对行业自身的结构性矛盾，加大力度，调整产业结构和产品结构，也就是应依靠质的提高，促进产品技术升级，以适应和拉动市场需求，求得更大的发展。
Hydraulic systemIntroductionHydraulic Pump Statio n also known as the statio ns are independent hydraulic device.It requested by the oil gradually. And contro lling the hydraulic oil flow direction, pressure and flow rate, applied to the mainframe and hydraulic devices separability of hydraulic machinery.Users will be provided after the purchase hydraulic statio n and host of imp lementing agencies (motor oil or fuel tanks) connected with tubing, Hydraulic machinery can be realized from these movements and the work cycle.Hydraulic pump station is installed, Manifo ld or valve combination, tanks, a comb inatio n of electrical boxes.Functio nal components :Pump device -- is equipped with motors and pumps, hydraulic statio n is the source of power. to mechanical energy into hydraulic oil pressure can be.Manifo ld -- fro m hydraulic valve body and channel assemb led. Right direction for imp lementatio n of hydraulic oil, pressure and flow control.Valve portfo lio -- plate valve is installed in up board after board connects with the same functional IC.Tank -- plate welding semi-closed containers, also loaded with oil filtering network, air filters, used oil, oil filters and cooling.Electrical boxes -- at the two patterns. A set of external fuse terminal plate; distrib ution of a full range of electrical control.Hydraulic Station princip le : motor driven pump rotation, which pump oil absorption fro m the oil tank. to mechanical energy into hydraulic pressure to the station, hydraulic oil through Manifo ld (or valve comb inations) realized the direction, pressure, After adjusting flow pipe and external to the cylinder hydraulic machinery or motor oil, so as to control the direction of the motivefluid transformatio n force the size and speed the pace of promoting the various acting hydraulic machinery.1.1A development courseChina Hydraulic (includ ing hydraulic, the same below), pneumatic and seals industrial development process can be broadly divided into three phases, namely : 20 early 1950s to the early 1960s, the initial stage; 60's and 70 for specialized production system ;80~90's growth stage for the rapid development stage. Which, hydraulic industry in the early 1950s from the machine tool industry production of fake Soviet Union grinder, broaching machine, copying lathe, and other hydraulic drive started, Hydraulic Components from the plant hydraulic machine shop, self-occupied. After entering the 1960s, the applicatio n of hydraulic technology from the machine gradually extended to the agricultural machinery and mechanical engineering fields, attached to the original velocity of hydraulic shop some stand out as pieces of hydraulic professional production. To the late 1960s, early 1970s, with the development of mechanized production, especially in the second automobile factory in providing efficient, auto mated equipment, along with the Hydraulic Components manufacturing has experienced rapid development o f the situation, a group of SME have become professional hydraulic parts factory. 1968 China's annual output of hydraulic components have nearly 200,000 in 1973, machine tools, agricultural machinery, mechanical engineering industries, the production of hydraulic parts factory has been the professio nal develop ment of more than 100 and an annual output more than one million. an independent hydraulic manufacturing ind ustry has begun to take shape. Then, hydraulic pieces of fake products fro m the Soviet Union for the introduction of the product develop ment and technical design comb ining the products to the pressure, Hypertension, and the development of the electro-hydraulic servo valves and systems, hydraulic application areas further expanded. Aerodynamic than the start of the ind ustrial hydraulic years later, in1967 began to establish professional pneumatic components factory, Pneumatic Components only as commodity production and sales. Sealed with rubber and plastics, mechanical seals and sealing flexib le graphite sealing industry, the early 1950s from the production ordinary O-rings. rubber and plastics extrusion, such as oil seal sealing and seal asbestos products start to the early 1960s, begun production o f mechanical seals and flexible graphite sealing products. 1970s, the burning of the former Ministry, a Ministry, the Ministry of Agricultural Mechanization System, a group of professional production plants have been established, and the official establishment of industries to seal ind ustrial development has laid the foundatio n for growth.Since the 1980s, in the country's reform and opening up policy guidelines, with the development of the machinery industry, based mainframe pieces behind the conflicts have become increasingly prominent and attracted the attentio n of the relevant departments. To this end, the Ministry o f the original one in 1982, formed the basis of common p ieces of Industry, will be scattered in the original machine tools, agricultural machinery, mechanical engineering industries centralized hydraulic, pneumatic and seals specialized factories, placing them under common management infrastructure pieces Bureau, so that the industry in the planning, investment, technolo gy and scientific research and development in areas such as infrastructure pieces Bureau of guidance and support. Since then entered a phase of rapid development, has introduced more than 60 items of advanced technology from abroad, includ ing more than 40 items of hydraulic, pneumatic 7. After digestion and absorptio n and transformation, now have mass production, and ind ustry-leading products. In recent years, the industry increased the techno logical transformatio n efforts, in 1991, Local enterprises and the self-financing total input o f about 20 b illion yuan, of which more than 1.6 billion yuan Hydraulic. Through techno logical transformatio n and techno logy research, and a number of major enterprises to further improve the level o f techno logy, technique and equip ment to be greatly improved. In order to form a higher starting point, specialization, and run production has laid a good foundation. Inrecent years, many countries in the develop ment of common owners hip guidelines, under different ownership SME rapid rise showing great vitality. With the further opening up, three-funded enterprises rapid development of industry standards for improving and expanding exports play an important role. Today, China has and the United States, Japan, Germany and other countries famous manufacturers joint ventures or wholly-owned by foreign manufacturers to establish a piston pump / motor, planetary reductio n gears, steering gear, hydraulic control valve, hydraulic system, hydrostatic transmission, hydraulic Casting. pneumatic contro l valve, cylinder, gas processing trip le pieces, mechanical seals, rubber and seal products more than 50 production enterprises, attracting foreign investment over 200 millio n U.S. dollars.1.2the current situation1.2.1Basic ProfilesAfter 40 years of efforts, China hydraulic, pneumatic and sealing ind ustry has formed a relatively comp lete categories. a certain level of technical capacity and the industrial system. According to the 1995 Third Natio nal Industrial Census statistics, hydraulic, Pneumatic seals and industrial 370,000 annual sales income of 100 million yuan in state-owned, village-run, private and cooperative enterprises, individual, "three capital" enterprises with a total of more than 1,300, of which about 700 hydraulic, Pneumatic seals and the approximately 300 thousand. By 1996 with the international trade statistics, the total output value of China's industry hydraulic 2.348 billion yuan, accounting for the world's 6; Pneumatic industry output 419 million yuan, accounting for world No. 10.1.22 the current supply and demand profilesThrough the introduction of technology, independent develop ment and technological innovation, and high-pressure piston pump, gear pumps, vane pump, General Motors hydraulic valves, tanks, Non-lubricated aerodynamic pieces and various seals of the first large techno logy products has increasednoticeably. stability of the mass production may, for various mainframe products provide a level of assurance. In addition, hydraulic and pneumatic components of the CAD system, pollution contro l, proportional servo techno logy has scored some achievements, and is already in production. Currently, hydraulic, pneumatic and seals products total about 3,000 species, more than 23,000 specifications. Among them, there are 1,200 hydraulic varieties, more than 10,000 specificatio ns (includ ing hydraulic products 60 varieties 500 specifications); Pneumatic are 1,350 varieties, more than 8,000 specifications; Rubber seal 350 species more than 5,000 specifications have been basically cater to the different types of mainframe products to the general needs, comp lete sets of equipment for major varieties of matching rate was over 60%, and started a small amount of exports.1998 p ieces of homemade hydraulic output 4.8 million. sales of about 28 billion (of which about 70% mechanical systems); aerodynamic pieces yield 3.6 million. sales of about 5.5 billion (of which about 60% of mechanical systems); Seals output o f about 800 million. sales of about 10 billion (of which about 50% mechanical systems). According to the China Hydraulic Pneumatic Seals Industry Association 1998 annual report, hydraulic product sales rate of 97. 5% (101% for hydraulic), pneumatic 95.9%, 98.7% sealed. This fully reflects the basic marketing convergence.My hydraulic, pneumatic and sealing industry has attained a great deal of progress, but with mainframe development needs, and the world's advanced level, there are still many gaps, mainly reflected in the product variety, performance and reliability, and so on. Hydraulic products as an examp le, products abroad only one-third, life for half abroad. In order to meet key mainframe, and mainframe imports of major techno logy and equip ment needs, every year a large number of hydraulic, pneumatic and sealing products imports. According to customs statistics and the analysis of data, in 1998 hydraulic, pneumatic and seals in the import about 200 million U.S. dollars, Hydraulic which about 1.4 billion dollars, aerodynamic nearly 030 millio n U.S. do llars, sealed about 030million U.S. dollars. compared with a slight decline in 1997. By sums, currently imported products on the do mestic market share of about 30%. 1998 pieces of the domestic market demand for hydraulic total o f about six million, the total sales of nearly 40 billion; aerodynamic pieces of the total demand of about 5 millio n, with sales more than 700 million yuan; Seals total demand of about 1.1 billio n. total sales of about 1.3 billion.1.3the development trend of the future1.31 affect the development of the main factors(1) product development ability, and the level o f techno logical development and speed can not comp letely meet the advanced mainframe products, major equip ment and technology imported equipment and maintenance support;(2) the number of enterprises manufacturing techno logy, the level of equip ment and management standards are comparatively backward, coupled with a strong sense of quality, resulting in low levels of product performance, quality, Reliability poor services in a timely manner, lack of user satisfaction and trust of the brand-name products;(3) ind ustry specializatio n of production low, scattered strength, low repeat serio us, between regions and enterprises of convergence products, blind ly compete with each other, driving down prices, the decline of enterprise returns, lack of funds, liq uidity difficulties, product development and technolo gical transformation is inadequate and seriously restricted the industry to improve the overall level of competition and the increase of strength;(4) The internationalization of the domestic market and the increasing degree of foreign companies have entered the Chinese market and participate in competition with the domestic private and cooperative enterprises, individuals, foreign-funded enterprises, such as the rise of state-owned enterprises due to the growing impact.1.32 the development trendAs the socialist market economy continues to deepen, hydraulic, pneumatic and sealing products in the market supply and demand and there is a greater change, long ago to a "shortage" of the seller's market has basically become a "structural surplus" of the characteristics of the buyer's market place . Overall capacity, is already in oversupply situation, in particular the general low level of hydraulic, pneumatic and seals, the general oversupp ly; and the host of urgent high-tech high-parameter, high value-added high-end products, and they do not satisfy the market needs, only dependent on imports. China joins the WTO, its impact may be even greater. Therefore, the "15" during the growth of the output value of ind ustry, must not depend on volume growth and the industry sho uld address the structural problems of their own, increase the intensity of the adjustment of the industrial structure and product mix, is, we should rely on the improvement of quality, and promote technical upgrading of products to meet market demand and stimulating, seek greater development.。