液压系统液压传动和气压传动毕业论文中英文资料对照外文翻译文献综述

液压机外文翻译文献(文档含中英文对照即英文原文和中文翻译)原文：The Analysis of Cavitation Problems in the Axial Piston Pumpshu WangEaton Corporation,14615 Lone Oak Road,Eden Prairie, MN 55344This paper discusses and analyzes the control volume of a piston bore constrained by the valve plate in axial piston pumps. The vacuum within the piston bore caused by the rise volume needs to be compensated by the flow; otherwise, the low pressure may cause the cavitations and aerations. In the research, the valve plate geometry can be optimized by some analytical limitations to prevent the piston pressure below the vapor pressure. The limitations provide the design guide of the timings andoverlap areas between valve plate ports and barrel kidneys to consider the cavitations and aerations. _DOI: 10.1115/1.4002058_ Keywords: cavitation , optimization, valve plate, pressure undershoots1 IntroductionIn hydrostatic machines, cavitations mean that cavities or bubbles form in the hydraulic liquid at the low pressure and collapse at the high pressure region, which causes noise, vibration, and less efficiency.Cavitations are undesirable in the pump since the shock waves formed by collapsed may be strong enough to damage components. The hydraulic fluid will vaporize when its pressure becomes too low or when the temperature is too high. In practice, a number of approaches are mostly used to deal with the problems: (1) raise the liquid level in the tank, (2) pressurize the tank, (3) booster the inlet pressure of the pump,(4) lower the pumping fluid temperature, and (5) design deliberately the pump itself.Many research efforts have been made on cavitation phenomena in hydraulic machine designs. The cavitation is classified into two types in piston pumps: trapping phenomenon related one (which can be prevented by the proper design of the valve plate)and the one observed on the layers after the contraction or enlargement of flow passages (caused by rotating group designs) in Ref. (1). The relationship between the cavitation and the measured cylinder pressure is addressed in this study. Edge and Darling (2) reported an experimental study of the cylinder pressure within an axial piston pump. The inclusion of fluid momentum effects and cavitations within the cylinder bore are predicted at both highspeed and high load conditions. Another study in Ref. (3) provides an overview of hydraulic fluid impacting on the inlet condition and cavitation potential. It indicates thatphysical properties (such as vapor pressure, viscosity, density, and bulk modulus) are vital to properly evaluate the effects on lubrication and cavitation. A homogeneous cavitation model based on the thermodynamic properties of the liquid and steam is used to understand the basic physical phenomena of mass flow reduction and wave motion influences in the hydraulic tools and injection systems (4). Dular et al. (5, 6) developed an expert system for monitoring and control of cavitations in hydraulic machines and investigated the possibility of cavitation erosion by using the computational fluid dynamics (CFD) tools. The erosion effects of cavitations have been measured and validated by a simple single hydrofoil configuration in a cavitation tunnel. It is assumed that the severe erosion is often due to the repeated collapse of the traveling vortex generated by a leading edge cavity in Ref. (7). Then, the cavitation erosion intensity may be scaled by a simple set of flow parameters: theupstream velocity, the Strouhal number, the cavity length, and the pressure. A new cavitation erosion device, called vortex cavitation generator, is introduced to comparatively study various erosion situations (8).More previous research has been concentrated on the valve plate designs, piston, and pump pressure dynamics that can be associated with cavitations in axial piston pumps. The control volume approach and instantaneous flows (leakage) are profoundly studied in Ref. [9]. Berta et al. [10] used the finite volume concept to develop a mathematical model in which the effects of port plate relief grooves have been modeled and the gaseous cavitation is considered in a simplified manner. An improved model is proposed in Ref.[11] and validated by experimental results. The model may analyze the cylinder pressure and flow ripples influenced by port plate and relief groove design. Manring comparedprincipal advantages of various valve plate slots (i.e., theslots with constant, linearly varying, and quadratic varyingareas) in axial piston pumps [12]. Four different numericalmodels are focused on the characteristics of hydraulic fluid,and cavitations are taken into account in different ways toassist the reduction in flow oscillations [13].The experiences of piston pump developments show thatthe optimization of the cavitations/aerations shall includethe following issues: occurring cavitation and air release,pump acoustics caused by the induced noises, maximal amplitudes of pressure fluctuations, rotational torque progression, etc. However, the aim of this study is to modifythe valve plate design to prevent cavitation erosions causedby collapsing steam or air bubbles on the walls of axial pump components. In contrast to literature studies, the researchfocuses on the development of analytical relationshipbetween the valve plate geometrics and cavitations. The optimization method is applied to analyze the pressure undershoots compared with the saturated vapor pressurewithin the piston bore.The appropriate design of instantaneous flow areas betweenthe valve plate and barrel kidney can be decided consequently.2 The Axial Piston Pump and Valve PlateThe typical schematic of the design of the axis piston pumpis shown in Fig. 1. The shaft offset e is designed in this caseto generate stroking containment moments for reducingcost purposes.The variation between the pivot center of the slipper andswash rotating center is shown as a. The swash angle αis the variable that determines the amount of fluid pumped pershaft revolution. In Fig. 1, the n th piston-slipper assembly is located at the angle of nθ. The displacement of the n thpiston-slipper assembly along the x-axis can be written asx n = R tan （α）sin （n θ）+ a sec （α） + e tan (α) (1) where R is the pitch radius of the rotating group. Then, the instantaneous velocity of the n th piston is x˙n = R 2sec ()αsin （n θ）α+ R tan （α）cos （n θ）ω+ R 2sec ()αsin （α）α + e 2sec ()αα (2) where the shaft rotating speed of the pump is ω=d n θ / dt .The valve plate is the most significant device to constraint flow in piston pumps. The geometry of intake/discharge ports on the valve plate and its instantaneous relative positions with respect to barrel kidneys are usually referred to the valve plate timing. The ports of the valve plate overlap with each barrel kidneys to construct a flow area or passage, which confines the fluid dynamics of the pump. In Fig. 2, the timing angles of the discharge and intake ports on the valve plate are listed as (,)T i d δ and (,)B i d δ. The opening angle of the barrel kidney is referred to as ϕ. In some designs, there exists asimultaneous overlap between the barrel kidney and intake/discharge slots at the locations of the top deadcenter (TDC) or bottom dead center (BDC) on the valve plate on which the overlap area appears together referred to as “cross-porting” in the pump design engineering. The cross-porting communicates the discharge and intake ports, which may usually lower the volumetric efficiency. The trapped-volume design is compared with the design of the cross-porting, and it can achieve better efficiency 14]. However, the cross-porting isFig. 1 The typical axis piston pump commonly used to benefit the noise issue and pump stability in practice.3 The Control Volume of a Piston BoreIn the piston pump, the fluid within one piston is embraced by the piston bore, cylinder barrel, slipper,valve plate, and swash plate shown in Fig. 3. There exist some types of slip flow by virtue of relative Fig. 2 Timing of the valve plate motions and clearances between thos e components. Within the control volume of each piston bore, the instantaneous mass is calculated asn M = ρn V (3) where ρ and n V are the instantaneous density and volume such that themass time rate of change can be given asFig. 3 The control volume of the piston boren n n dM dV d V dt dt dtρρ=+ (4)where d n V is the varying of the volume.Based on the conservation equation, the mass rate in the control volume isn n dM q dtρ= (5) where n q is the instantaneous flow rate in and out of onepiston. From the definition of the bulk modulus,n dP d dt dtρρβ= (6) where Pn is the instantaneous pressure within the piston bore. Substituting Eqs. (5) and (6) into Eq. (4) yields(?)n n n n n ndP q dV d V w d βθθ=- (7) where the shaft speed of the pump is n d dt θω=. The instantaneous volume of one piston bore can be calculated by using Eq. (1) asn V = 0V + P A [R tan （α）sin （n θ）+ a sec （α） + e tan (α) ](8) where P A is the piston sectional area and 0V is the volume of each piston, which has zero displacement along the x-axis (when n θ=0, π).The volume rate of change can be calculated at thecertain swash angle, i.e., α =0, such thattan cos n p n ndV A R d αθθ=（）（） (9) in which it is noted that the piston bore volume increases or decreases with respect to the rotating angle of n θ. Substituting Eqs. (8) and (9) into Eq. (7) yields0[tan()cos()] [tan sin sec tan() ]n P n n n p n q A R dP d V A R a e βαθωθαθαα-=-++（）（）（）(10)4 Optimal DesignsTo find the extrema of pressure overshoots and undershoots in the control volume of piston bores, the optimization method can be used in Eq. (10). In a nonlinear function, reaching global maxima and minima is usually the goal of optimization. If the function is continuous on a closed interval, global maxima and minima exist. Furthermore, the global maximum (or minimum) either must be a local maximum (or minimum) in the interior of the domain or must lie on the boundary of the domain. So, the method of finding a global maximum (or minimum) is to detect all the local maxima (or minima) in the interior, evaluate themaxima (or minima) points on the boundary, and select the biggest (or smallest) one. Local maximum or local minimum can be searched by using the first derivative test that the potential extrema of a function f( · ), with derivative ()f ', can solve the equation at the critical points of ()f '=0 [15]. The pressure of control volumes in the piston bore may be found as either a minimum or maximum value as dP/ dt=0. Thus, letting the left side of Eq. (10) be equal to zero yields tan()cos()0n p n q A R ωαθ-= (11) In a piston bore, the quantity of n q offsets the volume varying and then decreases the overshoots and undershoots of the piston pressure. In this study, the most interesting are undershoots of the pressure, which may fall below the vapor pressure or gas desorption pressure to cause cavitations. The term oftan()cos()p n A R ωαθ in Eq. (11) has the positive value in the range of intake ports (22ππθ-≤≤), shown in Fig. 2, which means that the piston volume arises. Therefore, the piston needs the sufficient flow in; otherwise, the pressure may drop.In the piston, the flow of n q may get through in a few scenarios shown in Fig. 3: (I) the clearance between the valve plate and cylinder barrel, (II) the clearance between the cylinder bore and piston, (III) theclearance between the piston and slipper, (IV) the clearance between the slipper and swash plate, and (V) theoverlapping area between the barrel kidney and valve plate ports. As pumps operate stably, the flows in the as laminar flows, which can be calculated as [16]312IV k k Ln i I k h q p L ωμ==∑ (12)where k h is the height of the clearance, k L is the passagelength,scenarios I –IV mostly have low Reynolds numbers and can be regardedk ω is the width of the clearance (note that in the scenario II,k ω =2π· r, in which r is the piston radius), and p is the pressure drop defined in the intake ports as p =c p -n p (13) where c p is the case pressure of the pump. The fluid films through the above clearances were extensively investigated in previous research. The effects of the main related dimensions of pump and the operating conditions on the film are numerically clarified in Refs. [17,18]. The dynamic behavior of slipper pads and the clearance between the slipper and swash plate can be referred to Refs. [19,20]. Manring et al. [21,22]investigated the flow rate and load carrying capacity of the slipper bearing in theoretical and experimental methods under different deformation conditions. A simulation tool called CASPAR is used to estimate the nonisothermal gap flow between the cylinder barrel and the valve plate by Huang and Ivantysynova [23]. The simulation program also considers the surface deformations to predict gap heights, frictions, etc., between the piston and barrel and between the swash plate and slipper. All these clearance geometrics in Eq. (12) are nonlinear and operation based, which is a complicated issue. In this study, the experimental measurements of the gap flows are preferred. If it is not possible, the worst cases of the geometrics or tolerances with empirical adjustments may be used to consider the cavitation issue, i.e., minimum gap flows.For scenario V, the flow is mostly in high velocity and can be described by using the turbulent orifice equation as((Tn d i d d q c A c A θθ= (14) where Pi and Pd are the intake and discharge pressure of the pump and ()i A θ and ()d A θ are the instantaneousoverlap area between barrel kidneys and inlet/discharge ports of the valve plate individually.The areas are nonlinear functions of the rotating angle, which is defined by the geometrics of the barrel kidney, valve plate ports, silencing grooves, decompression holes, and so forth. Combining Eqs. (11) –(14), the area can beobtained as3()K IV A θ==(15)where ()A θ is the total overlap area of ()A θ=()()i d A A θλθ+, andλis defined as=In the piston bore, the pressure variesfrom low to high while passing over the intake and discharge ports of the valve plates. It is possible that the instantaneous pressure achieves extremely low values during the intakearea( 22ππθ-≤≤ shown in Fig. 2) that may be located below the vapor pressure vp p , i.e., n vp p p ≤;then cavitations canhappen. To prevent the phenomena, the total overlap area of ()A θmight be designed to be satisfied with30()K IV A θ=≥(16)where 0()A θ is the minimum area of 0()A θ=0()()i d A A θλθ+and0λis a constant that is0λ=evaporates into a gaseous form. The vapor pressure of any substance increases nonlinearly with temperature according to the Clausius –Clapeyron relation. With the incremental increase in temperature, the vapor pressure becomes sufficient to overcome particle attraction and make the liquid form bubbles inside the substance. For pure components, the vapor pressure can be determined by the temperature using the Antoine equation as /()10A B C T --, where T is the temperature, and A, B, and C are constants [24]. As a piston traverse the intake port, the pressure varies dependent on the cosine function in Eq. (10). It is noted that there are some typical positions of the piston with respect tothe intake port, the beginning and ending of overlap, i.e., TDC and BDC (/2,/2θππ=- ) and the zero displacement position (θ =0). The two situations will be discussed as follows: (1) When /2,/2θππ=-, it is not always necessary to maintain the overlap area of 0()A θ because slip flows may provide filling up for the vacuum. From Eq. (16), letting 0()A θ=0,the timing angles at the TDC and BDC may be designed as31cos ()tan()122IV c vpk k i I P k p p h A r L ωϕδωαμ--≤+∑ (17) in which the open angle of the barrel kidney is . There is no cross-porting flow with the timing in the intake port.(2) When θ =0, the function of cos θ has the maximum value, which can provide another limitation of the overlap area to prevent the low pressure undershoots suchthat 30(0)K IV A =≥ (18)where 0(0)A is the minimum overlap area of 0(0)(0)i A A .To prevent the low piston pressure building bubbles, the vapor pressure is considered as the lower limitation for the pressure settings in Eq. (16). The overall of overlap areas then can be derived to have a design limitation. The limitation is determined by the leakage conditions, vapor pressure, rotating speed, etc. It indicates that the higher the pumping speed, the more severe cavitation may happen, and then the designs need more overlap area to let flow in the piston bore. On the other side, the low vapor pressure of the hydraulic fluid is preferred to reduce the opportunities to reach the cavitation conditions. As a result, only the vapor pressure of the pure fluid is considered in Eqs. (16)–(18). In fact, air release starts in the higher pressure than the pure cavitation process mainly in turbulent shear layers, which occur in scenario V. Therefore, the vapor pressure might be adjusted to design the overlap area by Eq. (16) if there exists substantial trapped and dissolved air in the fluid. The laminar leakages through the clearances aforementioned are a tradeoff in the design. It is demonstrated that the more leakage from the pump case to piston may relieve cavitation problems.However, the more leakage may degrade the pump efficiency in the discharge ports. In some design cases, the maximum timing angles can be determined by Eq. (17)to not have both simultaneous overlapping and highly low pressure at the TDC and BDC. While the piston rotates to have the zero displacement, the minimum overlap area can be determined by Eq. 18 , which may assist the piston not to have the large pressure undershoots during flow intake.6 Conclusions The valve plate design is a critical issue in addressing thecavitation or aeration phenomena in the piston pump. This study uses the control volume method to analyze the flow, pressure, and leakages within one piston bore related to the valve plate timings. If the overlap area developed by barrel kidneys and valve plate ports is not properly designed, no sufficient flow replenishes the rise volume by the rotating movement. Therefore, the piston pressure may drop below the saturated vapor pressure of the liquid and air ingress to form the vapor bubbles. To control the damaging cavitations, the optimization approach is used to detect the lowest pressure constricted by valve plate timings. The analytical limitation of the overlap area needs to be satisfied to remain the pressure to not have large undershoots so that the system can be largely enhanced on cavitation/aeration issues. In this study, the dynamics of the piston control volume is developed by using several assumptions such as constant discharge coefficients and laminar leakages. The discharge coefficient is practically nonlinear based on the geometrics, flow number, etc. Leakage clearances of the control volume may not keep the constant height and width as well in practice due to vibrations and dynamical ripples. All these issues are complicated and very empirical and need further consideration in the future. The results presented in this paper can be more accurate in estimating the cavitations with these extensive studies. Nomenclature0(),()A A θθ= the total overlap area between valve plate ports and barrel kidneys 2()mm Ap = piston section area 2()mm A, B, C= constants A= offset between the piston-slipper joint and surface of the swash plate 2()mmd C = orifice discharge coefficiente= offset between the swash plate pivot and the shaft centerline of the pump 2()mmk h = the height of the clearance 2()mmk L = the passage length of the clearance 2()mm M= mass of the fluid within a single piston (kg) N= number of pistons n = piston and slipper counter,p p = fluid pressure and pressure drop (bar) Pc= the case pressure of the pump (bar) Pd= pump discharge pressure (bar) Pi = pump intake pressure (bar) Pn = fluid pressure within the nth piston bore (bar) Pvp = the vapor pressure of the hydraulic fluid(bar) qn, qLn, qTn = the instantaneous flow rate of each piston (l/min) R = piston pitch radius 2()mmr = piston radius (mm )t =time (s )V = volume 3()mmwk = the width of the clearance (mm )x ,x˙= piston displacement and velocity along the shaft axis (m, m/s )x y z --=Cartesian coordinates with an origin on the shaft centerlinex y z '''--= Cartesian coordinates with an origin on swash plate pivot,αα=swash plate angle and velocity (rad, rad/s )β= fluid bulk modulus (bar ),B T δδ= timing angle of valve plates at the BDC and TDC (rad ) ϕ = the open angle of the barrel kidney (rad )ρ= fluid density (kg /m3),θω = angular position and velocity of the rotating kit (rad, rad/s )μ =absolute viscosity (Cp ),λλ=coefficients related to the pressure drop翻译：在轴向柱塞泵气蚀问题的分析本论文讨论和分析了一个柱塞孔与配流盘限制在轴向柱塞泵的控制量设计。

中国地质大学长城学院本科毕业设计外文资料翻译系别工程技术系专业机械设计制造及其自动化学生姓名彭江鹤学号 05211534指导教师王泽河职称教授2015 年 5 月 4 日液压传动系统作者：Hopmans, ArthurH.摘要液压传动是由液压泵、液压控制阀、液压执行元件和液压辅件组成的液压系统。

液压泵把机械能转换成液体的压力能，液压控制阀和液压辅件控制液压介质的压力、流量和流动方向，将液压泵输出的压力能传给执行元件，执行元件将液体压力能转换为机械能，以完成要求的动作。

关键词：液压传动；气压传动；传动系统；许多液压传动先前已经设计出允许操作者无限变化输出的变速器，或甚至逆转的传动装置的输出作为相对于输入。

通常情况下，这已经通过使用一个旋转斜盘是要么由操作者手动或操作液压动机来改变通过旋转泵头部具有轴向移动的活塞流动的液压流体的。

液压流体从泵头活塞的流动，依次转动的马达头通过激励相应的一组活塞在其中违背一固定凸轮的，因此，旋转安装在电动机头的输出轴。

通常情况下，在现有技术的变速器已被被设置有各种功能，例如齿轮减速，刹车设定装置等。

不幸的是，这些功能通常是提供外部发送的和显著增加整个装置的体积和质量。

申请人确定，这是很期望具有其中基本上所有的这些需要或希望的功能，可以在内部提供的发送，同时还产生一个非常有效的和非常有效的传输的综合传输。

特别是，这种类型的变速器上经常使用的设备，如“零转动半径”剪草机之类的其中一个潜在的危险情况面对操作者，旁观者和设备本身，如果设备我们允许继续被推进应的操作者释放控制，由于当操作者无意中从装置抛出或变得受伤。

因此，“故障自动刹车”机制经常被设置为传输自动地返回到中立配置在这种情况下，使得该装置不会继续供电，如果控制被释放。

先前传输这种类型的一般依靠某种外部设备，比如其目的是为了在操作者控制轴返回到中立位置应操作者释放所述轴的反操作偏压弹簧。

这种类型的外部设备，可以容易地由用户或篡改损坏。

fluid driven and transmission oilFormer statement fluid transmission is including gas (pressure) transmission and liquid transmission, hydraulic transmission into liquid transmission, hydraulic transmission and fluid Nien transmission. Hydraulic transmission based on the interior market, the pressure to be able to impart impetus liquid; Hydraulic transmission based on Oula equation to the liquid changes to the short wheel drive transmission; For Newton, Nien transmission fluid friction law, the sticky liquid to impart dynamism to.Hydraulic transmission is the basic hydraulic components and hydraulic Bianjuqi coupled device. Hydraulic coupled devices is a fundamental component of a number of radial plane leaves, a work of the pump and turbine round. Hydraulic transmission oil in the work of the cycle of high-speed mobile transmission power, oil pumps round her so involved with the campaign because centrifugal force role do centrifuge campaign from pumps round (and imported axis) and to absorb mechanical energy into moment of momentum (mVR) incremental, high-speed Yeliu round water from the pump to the heart to do turbine flow release moment of momentum. promote turbine (and export axis) rotation, work-driven plane (and load) homework. Hydraulic Bianjuqi basic components are pumps round, and the turbine-round, they are a space (bending) leaves work round by the work of a relevant order. Hydraulic transmission oil pumps were working round the turbine mix for incremental Ye Liu was moment of momentum, after transfer-round water turbine Yeliu direction after the release of moment of momentum (kinetic energy) to promote the work of the turbine-driven rotary rush.My hydraulic components in the development of faster, 2003 hydraulic coupled devices produced about 70,000 National Taiwan. Widely used for Daishishusongji, rail carriers, ball mill, air-compressors, compressors, pumps and fuel pumps, and other equipment, transmission, improve transmission quality and energy conservation. My hydrauliccoupled with the current maximum output rotational speed for 6500r/min, minimum power to 0.3kW, the maximum power to 7100kW. Hydraulic trend is coupled with a high rotational speed and power.International hydraulic coupled device products to the most famous German Fuk under special company, according to information that has reached 20000r/min rotational speed and power to 55000kW products, which are still visible in considerable gap. Of course, the power of the big oil hydraulic components for hydraulic transmission requirements higher. Hydraulic Bianjuqi mainly for engineering machinery, machinery and diesel oil. Hydraulic Bianjuqi main internal combustion engine with matching applications, the scope of its rotational speed in 2000~3000r/min. Mechanical engineering applications more, the greatest power 700HP about output about 70,000 Taiwan. Oil machinery applications less power to 1500HP. Diesel applications less power up 3000HP.Nien transmission fluid is a liquid transmission doors emerging disciplines in the country are still at an infancy stage. Because liquid Nien transmission products (such as fluid mechanics using Nien) and hydraulic transmission products (such as governor-hydraulic coupled device) Notwithstanding the different nature, but because of similar performance and the same purposes (governor energy), in a number of technical activities (such as the formulation of development plans, standards, technology management, orders, and other activities) are regarded as the same type, with the hydraulic industry commonalities, it is another chapter on the work of its product mix and transmission oil.First, the performance characteristics of the oil and hydraulic transmission hydraulic transmission oil development not only as a transmission medium for work, but also to provide lubrication bearings and gear while the carrier is further bad fever, heat away. Hydraulic transmission oil is a complex and require specialized research topics, which is directly related to the reliability of hydraulic components,transmission efficiency and service life. Should arouse the attention of extensive in-depth study.Hydraulic transmission oil should meet the following requirements : 1、A suitable low-viscosity liquid viscosity, liquid indicate friction within small, mobile resistance small loss may reduce hydraulic components hydraulic losses; But lubricant sealed perspective, the viscosity can not be too low. Provide lubrication and therefore should meet the requirements of sealed premise as a low-viscosity liquid to improve hydraulic components transmission efficiency. Wen Xing Nien also called liquid than for the high-temperature or low-temperature, and still maintain an effective lubricant sealed.2、A greater emphasis on the hydraulic components for the moment and the power transmission and liquid working for the re-direct, it is liquid-degrees the higher the better.3、The performance can have a stable bubble, aging and sedimentation.4、Suanzhi sealed pieces to be neutral to low, and a good compatibility, not dwell inflation, not dissolved, the non-corrosive metal.5、A higher flash point and lower congeal point hydraulic components work Youwen change significantly, sometimes up to 160 degrees, and therefore require flash point higher than 180 degrees, and congeal point lower than -20 degrees, low-temperature environment for the benefit of the start-up of hydraulic components.6、A good lubricant performance liquid sufficient greasiness to the good parts in the surface material, a good lubricant.At present, and hydraulic transmission applications work more liquid types, among all oil-based products, has used the water or other liquid Nanran (coal mine explosion and fire in defense applications). Domestic hydraulic components commonly used 6th hydraulic transmission oil (also useful 8th hydraulic transmission oil), and sometimes to 22 turbine fuel substitution.Diesel oil is dedicated to the life of not less than 2,000 hours andfor the initial operation of new equipment installed oil after 100 hours and 500 hours of the first, second formula, can still be used after the filter.Is one of the following situations, the need to replace the new oil : Water content greater than 0.2%; 50 degrees in the new oil viscosity higher than 6% mounted; Mechanical impurities (benzene Burong objects) to reach 0.2%; A high lipid intake or Suanzhi; Excessive bubble effects transmission power. More articles on the diesel-hydraulic transmission oil outside the oil will definitely reference value.Second, Transmission and hydraulic oil brands in (slightly)Third, Fluid Nien transmission of the oil transmission fluid requirements may Nien Tien National Petroleum Corporation December thickness operational changes are divided into two categories : one category is in operation slick thickness constant fluid Nien transmission, such as silicone oil slick thickness using fans is fixed, changes in the operational work of the degree to which oil-exporting rotational speed. Another operation is slick thickness is variable fluid Nien transmission, such fluid Nien Nien transmission products including fluid mechanics using, liquid Nien brakes, fluids Nien dynamometer, fluid Nien shaft coupling, fluid mechanics Nien devices. Current applications are more fluid mechanics using Nien, fluid mechanics devices and silicone oil Nien fans Clutch.1、Fluid mechanics using Nien and transmission oil fluid mechanics using Nien through its owners, driven friction between the film to a number of oil transmission power, relying on the apparent effectiveness initiative friction films "draw" driven friction with the direction of rotation films, transmission moment with oil viscosity, two films - "goes bad" proportional, and with oil thickness (films gap) negatively. Initiative friction films and imported axle and power machine linked to the importation of rotational speed as constants. Driven friction films and the work associated with the export of axle, and the output rotational speed with control pressure changes, spherical tank pressure control, a slick filmthinning, export rotational speed rise, and vice versa. When the control pressure enough, the owners, driven friction films together into the transmission straight. When sufficient pressure control small owners, driven films from friction, zero export rotational speed. Nien in fluid mechanics using rotational speed than 0>1 change from the process of film-friction conditions showing a liquid friction "(a mechanical liquid) mixed friction" (purely mechanical) border friction. Therefore fluid mechanics using Nien are in the process of separation-state governor, the state governor and the state face. Work in fluid liquid is the role of transmission Nien transmission power, heat dissipation and cooling lubricant should have the following functions : (1) the appropriate viscosity. (2) is a good lubricant performance (greasiness and very pressurised nature). (3) a good oxidation insecurities. (4) higher than the thermal capacity and higher heat conductivity. In addition to the above requirements, but also work with rustproof liquid role, anti-bubble capacity, congeal points lower, flash point should be high, not volatile, non-toxic. Nien currently made in China fluid mechanics using more oil as a hydraulic transmission work on the 8th of liquid. The domestic fluid mechanics using a TL - Nien and HC type rated rotational speed mostly 1500r/min, individual 3000r/min. 75kW power transmission smallest, the largest of 1100kW. Fluid mechanics starts with the mechanics of hydraulic Nien coupled devices, are in the rotational speed electrical driven downward in the low-speed, power and small, inefficient. To this end in fluid mechanics using input Nien before or after the installation of vertical transmission-export, or to meet with the power machine and the matching machine work, so a new device -- liquid Nien governor devices.2、Fluid mechanics devices Nien current production and application of two different structures liquid Nien governor devices, a category is the U.S. Philadelphia drove parallel axle fluid production company Nien governor devices into rotational speed 1785r/min exporting rotational speed 5000r/min, transmitting power to 5200kW. My hill Xian too Salihcoal mine in the smaller Daishishusongji specifications. Oil is brought by the United States of its transmission. Baoding propeller factory design, produced with structurally similar products. Another is the United States Dodge (Dodge) companies CST fluid mechanics devices Nien, it is in Park pillar gear -- planetary reducer round of the robustness of the export-round, and export axis (connecting the Sun round), in parallel with export large Chijuan fluid mechanics using Nien (driven friction films fixed), start-up liquid separation Nien governor in the state starts (idling), gradually increasing pressure control, when his transmission torque and the torque equivalent output bearings, export axle (with load) started turning and continue to increase the pressure until the joint control of the situation, the export axle assume full power output. CST fluid mechanics device known as Nien large Daishishusongji soft start system in the country's major coal Daishishusongji already applied. CST series products, the importation of rotational speed 1483r/min, rated slowdown than to 15.38~57.66, transmitting power scope 702~3115kW. CST series of products supplied by the United States dedicated hydraulic transmission oil.3、Silicone oil producing fans with liquid silicone oil work of the fan clutch, driven plate with a 78-98 derby leaves, the two derby leaves mutual alternate inserted, a number Park derby gap (oil), use these links, the sticky oil to impart momentum. The process of routing thickness unchanged through changes Chongyou volume and the size of the area to exploration by sheared governor.Engine in the appropriate temperature can be higher fuel efficiency, overheating is not too cold. Automotive firm to offer fans of silicone oil and engine linked driven sites linked with the fans, for liquid silicone oil viscosity larger. On temperature devices for cooling water to control the rear airflow temperature feelings Chongyou volume. When the engine cooling water temperature low, the air currents temperature low temperature equipment made Chongyou small amount of oil shearedsmall size, transmission moment small, low rotational speed fans for the engine cooling capacity low. Conversely, when the engine cooling water temperature is high, the fans rotational speed is high, awareness of the engine cooling effect. This will allow a regular in the most appropriate temperature. Fuel efficiency, noise small, extended engine life.Silicone oil used silicone oil is a fan using synthetic lubricants, not petroleum refining come from. It is the semi-organic silicon polymers or copolymer, containing duplicate silicon modules for yuan oxygen machine backbone, and the silicon atoms along the chain, replace clustering levonorgestrel, the general chain-guns. To meet the prescribed performance requirements, availability of different organic polymers to replace the base elements or the size of the adjustment (that is, to change its molecular weight), to change its viscosity or acquire other properties.Silicone oil depends on the physical properties of polymer molecular structure, such as molecular weight, organic genetic types and quantity, location and length of extension chain. In the liquid oil thickness constant use silicone oil Nien transmission of the main reasons is that it has a high viscosity, good performance and strong resistance Nien Wen sheared capacity.Silicone oil can be used in all types of vehicles using fans, currently our applications are mainly jeeps, and other vehicles Beijing 130. Motor oil production plant with Beijing and Changchun First Automobile Works Bengchang units.液压传动和传动油流体传动包括气体(压)传动和液体传动，液体传动分为液压传动、液力传动和液粘传动。

液压英文文献及翻译液压系统1.绪论液压站称液压泵站，是独立的液压装置。

它是按逐级要求供油。

并控制液压油流方向、压力和流量，适用在主机与液压装置可分离的各种液压机械上面。

用户在购后只要将液压站与主机上执行机构（油缸或油马达）用不同的油管相连，液压机械即实现各种规定的动作与工作循环。

液压站是由集成块、泵装置或阀组合、电气盒、油箱电气盒组合而成。

各个部件功能为：泵装置——上装有电机和油泵，其是液压站的动力源，能将机械能转化为液压油压力能。

阀组合－－其板式阀装在立板上，板后管连接，与集成块的功能相同。

油集成块－－是由液压阀及通道体组装而成。

其对液压油实行压力、方向和流量调节。

箱－－是板焊的半封闭容器，上面还装有滤油网、空气滤清器等，是用来储油与油的冷却及过滤。

电气盒－－分两种型式：一种是设置外接引线的端子板；一种是配置了全套控制电器。

液压站工作原理：电机带动油泵转动，然后泵从油箱中吸油并供油，将机械能转化为液压站压力能，液压油通过集成块（或阀组合）实现方向、压力、流量调节后经过外接管路并至液压机械里的油缸或油马达中，从而控制液动机方向变换、力量的大小及速度的快慢，来推动各种液压机械做功。

(1)液压的发展历程在我国液压（含液力，下同）、气动和密封件工业的发展历程，大致可分成三个阶段，即：在20世纪50年代初到60年代初是起步阶段；60-70年代为专业化生产体系的成长阶段；80-90年代为快速发展阶段。

在其中，液压工业始于50年代初从机床行业生产的仿苏的磨床、拉床、仿形车床等液压传动来起步，液压元件由机床厂里的液压车间生产，自产自用。

在进入60年代后，液压技术应用从机床逐渐推广到农业机械与工程机械等领域，原来附属于主机厂里的液压车间有些独立出来，成为液压件的专业生产厂。

在60年代末、70年代初，随着生产机械化的不断发展，特别是在为第二汽车制造厂等提供了高效、自动化设备的带动下，液压元件制造业出现了不断迅速发展的局面，一批中小企业也开始成为液压件专业制造厂。

河南理工大学万方科技学院本科毕业论文附录：外文资料与翻译院（系部）机械与动力工程系专业名称机械设计制造及自动化年级班级 08机设2班学生姓名杨涛指导老师牛振华2012年05月外文资料与中文翻译外文资料：Hydraulic Station and the development of hydraulic components Profiles Hydraulic Pump Station also known as the stations are independent h- ydraulic device.It requested by the oil gradually. And controlling the hydraulic oil flow direction, pressure and flow rate, applied to the mainframe and hy- draulic devices separability of hydraulic machinery.Users will be provided after the purchase hydraulic station and host of implementing 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, Manifold or valve combination, t- anks, a combination of electrical boxes.Functional components :Pump device -- is equipped with motors and pumps, hydraulic station is the source of power. to mechanical energy into hydraulic oil pressure can be.Manifold -- from hydraulic valve body and channel assembled. Right direction for implementation of hydraulic oil, pressure and flow control.Valve portfolio -- plate valve is installed in up board after board conn-ects 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; distribution of a full range of electrical control.Hydraulic Station principle : motor driven pump rotation, which pump oil absorption from the oil tank. to mechanical energy into hydraulic pressure to the station, hydraulic oil through Manifold (or valve combinations) 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 motive fluid transformation force the size and speed the pace of promoting the various acting hydraulic machinery.A development courseChina Hydraulic (including hydraulic, the same below), pneumatic and seals industrial development process can be broadly divided into three phases, namely : 20 early 1950sto 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 Su-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 application 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, automated equipment, along with the Hydraulic Components manufacturing has experienced rapid development of the situation, a group of SMEs 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 professional development of more than 100 and an annual output more than one million. an independent hydraulic manufacturing industry has begun to take shape. Then, hydraulic pieces of fake products fromthe Soviet Union for the introduction of the product development and technical design combining 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 industrial hydraulic years later, in 1967 began to establish professional pneumatic components factory, Pneumatic Components only as commodity production and sales. Sealed with rubber and plastics, mechanical seals and sealing flexible 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 of 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 industrial development has laid the foundation 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 attention of the relevant departments. To this end, the Ministry of the original one in 1982, formed the basis of common piecesof 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, technology 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, including more than 40 items of hydraulic, pneumatic 7. After digestion and absorption and transformation, now have mass production, and industry-leading products. In recent years, the industry increased the technological transformation efforts, in 1991, Local enterprises and the self-financing total input of about 20 billion yuan, of which more than 1.6 billion yuan Hydraulic. Through technological transformation and technology research, and a number of major enterprises to further improve the level of technology, technique and equipment to be greatly improved. In order to form a higher starting point, specialization, and run production has laid a good foundation. In recent years, many countries in the development of common ownership guidelines, under different ownership SMEs 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 reduction gears, steering gear, hydraulic control valve, hydraulic system, hydrostatic transmission, hydraulic Casting. pneumatic control valve, cylinder, gas processing triple pieces, mechanical seals, rubber and seal products more than 50 production enterprises, attracting foreign investment over 200 million U.S. dollars.Second, the current situation(1) Basic ProfilesAfter 40 years of efforts, China hydraulic, pneumatic and sealing industry has formed a relatively complete categories. a certain level of technical capacity and the industrial system. According to the 1995 Third National 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 outputvalue 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.(2) the current supply and demand profilesThrough the introduction of technology, independent development 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 technology products has increased noticeably. 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 control, proportional servo technology 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 specifications (including 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, complete sets of equipment for major varieties of matching rate was over 60%, and started a small amount of exports.1998 pieces 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 of 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 example, products abroad only one-third, life for half abroad. In order to meet key mainframe, and mainframe imports of major technology and equipment 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 million U.S. dollars, sealed about 030 million U.S. dollars. compared with a slight decline in 1997. By sums, currentlyimported products on the domestic market share of about 30%. 1998 pieces of the domestic market demand for hydraulic total of about six million, the total sales of nearly 40 billion; aerodynamic pieces of the total demand of about 5 million, with sales more than 700 million yuan; Seals total demand of about 1.1 billion. total sales of about 1.3 billion.Third, the development trend of the future1, affect the development of the main factors(1) product development ability, and the level of technological development and speed can not completely meet the advanced mainframe products, major equipment and technology imported equipment and maintenance support;(2) the number of enterprises manufacturing technology, the level of equipment 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) industry specialization of production low, scattered strength, low repeat serious, between regions and enterprises of convergence products, blindly compete with each other, driving down prices, the decline of enterprise returns, lack of funds, liquidity difficulties, product development and technological transformation is inadequateand 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.2, 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 oversupply; 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 industry, must not depend on volume growth and the industry should address the structural problems of their own, increase the intensity of the adjustment of the industrial structure and productmix, is, we should rely on the improvement of quality, and promote technical upgrading of products to meet market demand and stimulating, seek greater development.中文翻译：液压站及液压元件发展概况液压站又称液压泵站，是独立的液压装置。

外文文献翻译(含：英文原文及中文译文)英文原文Hydraulic systemW Arnold1 IntroductionThe hydraulic station is called a hydraulic pump station and is an independent hydraulic device. It is step by step to supply oil. And control the direction of hydraulic oil flow, pressure and flow, suitable for the host and hydraulic equipment can be separated on the various hydraulic machinery.After the purchase, the user only needs to connect the hydraulic station and the actuator (hydraulic or oil motor) on the mainframe with different tubings. The hydraulic machine can realize various specified actions and working cycles.The hydraulic station is a combination of manifolds, pump units or valve assemblies, electrical boxes, and tank electrical boxes. Each part function is:The pump unit is equipped with a motor and an oil pump, which is the power source of the hydraulic station and can convert mechanical energy into hydraulic oil pressure energy.V alve combination - its plate valve is mounted on the vertical plate, and the rear plate is connected with the same function as the manifold.Oil manifolds - assembled from hydraulic valves and channel bodies. It regulates hydraulic oil pressure, direction and flow.Box--a semi-closed container for plate welding. It is also equipped with an oil screen, an air filter, etc., which is used for cooling and filtering of oil and oil.Electrical box - divided into two types: one is to set the external lead terminal board; one is equipped with a full set of control appliances.The working principle of the hydraulic station: The motor drives the oil pump to rotate, then the pump sucks oil from the oil tank and supplies oil, converts the mechanical energy into hydraulic pressure energy, and the hydraulic oil passes through the manifold (or valve assembly) to adjust the direction, pressure and flow and then passes through the external tube. The way to the hydraulic cylinder or oil motor in the hydraulic machinery, so as to control the direction of the hydraulic motor, the strength of the speed and speed, to promote all kinds of hydraulic machinery to do work.(1) Development history of hydraulic pressureThe development history of hydraulics (including hydraulic power, the same below), pneumatics, and seals industry in China can be roughly divided into three stages, namely: the starting stage in the early 1950s to the early 60s; and the professional in the 60s and 70s. The growth stage of the production system; the 80-90's is a stage of rapid development. Among them, the hydraulic industry began in the early 1950s with thedevelopment of hydraulic machines such as Grinding Machines, broaching machines, and profiling lathes, which were produced by the machine tool industry. The hydraulic components were produced by the hydraulic workshop in the machine tool factory, and were produced for self use. After entering the 1960s, the application of hydraulic technology was gradually promoted from the machine tool to the agricultural machinery and engineering machinery. The original hydraulic workshop attached to the main engine plant was independent and became a professional manufacturer of hydraulic components. In the late 1960s and early 1970s, with the continuous development of mechanization of production, particularly in the provision of highly efficient and automated equipment for the second automobile manufacturing plant, the hydraulic component manufacturing industry witnessed rapid development. The batch of small and medium-sized enterprises also began to become specialized manufacturers of hydraulic parts. In 1968, the annual output of hydraulic components in China was close to 200,000 pieces. In 1973, in the fields of machine tools, agricultural machinery, construction machinery and other industries, the professional factory for the production of hydraulic parts has grown to over 100, and its annual output exceeds 1 million pieces. Such an independent hydraulic component manufacturing industry has taken shape. At this time, the hydraulic product has evolved from the original imitation Su product intoa combination of imported technology and self-designed products. The pressure has been developed towards medium and high pressures, and electro-hydraulic servo valves and systems have been developed. The application of hydraulics has been further expanded. The pneumatic industry started a few years later than hydraulics, and it was only in 1967 that it began to establish a professional pneumatic components factory. Pneumatic components began to be manufactured and sold as commodities. Its sealing industry including rubber seals, flexible graphite seals, and mechanical seals started from the production of common O-rings, oil seals, and other extruded rubber seals and asbestos seal products in the early 1950s. In the early 1960s, it began to develop and produce flexible products. Graphite seals and mechanical seals and other products. In the 1970s, a batch of batches of professional production plants began to be established one after another in the systems of the former Ministry of Combustion, the Ministry of Agriculture, and the Ministry of Agricultural Machinery, formally forming the industry, which laid the foundation for the development of the seal industry.In the 1980s, under the guidance of the national policy of reform and opening up, with the continuous development of the machinery industry, the contradiction between the basic components lags behind the host computer has become increasingly prominent and caused the attention of all relevant departments. To this end, the former Ministry of Machinesestablished the General Infrastructure Industry Bureau in 1982, and unified the original pneumatic, hydraulic, and seal specialties that were scattered in the industries of machine tools, agricultural machinery, and construction machinery, etc. The management of a piece of office, so that the industry in the planning, investment, the introduction of technology and scientific research and development and other aspects of the basic parts of the bureau's guidance and support. This has entered a period of rapid development, it has introduced more than 60 foreign advanced technology, of which more than 40 hydraulic, pneumatic 7, after digestion and absorption and technological transformation, are now mass production, and has become the industry's leading products . In recent years, the industry has intensified its technological transformation. From 1991 to 1998, the total investment of national, local, and corporate self-raised funds totaled about 2 billion yuan, of which more than 1.6 billion were hydraulic. After continuous technological transformation and technological breakthroughs, the technical level of a group of major enterprises has been further improved, and technological equipment has also been greatly improved, laying a good foundation for forming a high starting point, specialization, and mass production. In recent years, under the guidance of the principle of common development of multiple ownership systems in the country, various small and medium-sized enterprises with different ownership have rapidly emerged and haveshown great vitality. With the further opening up of the country, foreign-funded enterprises have developed rapidly, which plays an important role in raising industry standards and expanding exports. So far China has established joint ventures with famous manufacturers in the United States, Germany, Japan and other countries or directly established piston pumps/motors, planetary speed reducers, hydraulic control valves, steering gears, hydraulic systems, hydrostatic transmissions, and hydraulic components. The company has more than 50 manufacturing enterprises such as castings, pneumatic control valves, cylinders, gas processing triplets, rubber seals, and mechanical seals, and has attracted more than 200 million U.S. dollars in foreign capital.(2) Current statusBasic profileAfter more than 40 years of hard work, China's hydraulics, pneumatics and seals industry has formed a complete industrial system with a certain level of production capacity and technical level. According to the statistics of the third n ational industrial census in 1995, China’s state-owned, privately-owned, cooperative, village-run, individual, and “funded enterprises” have annual sales income of more than 1 million yuan in hydraulic, pneumatic, and seal industrial townships and above. There are a total of more than 1,300 companies, including about 700 hydraulics, and about 300 pneumatic and sealing parts. According to thestatistics of the international industry in 1996, the total output value of the hydraulic industry in China was about 2.448 billion yuan, accounting for the 6th in the world; the total output value of the pneumatic industry was about 419 million yuan, accounting for the world’s10 people.2. Current supply and demand profileWith the introduction of technology, independent development and technological transformation, the technical level of the first batch of high-pressure plunger pumps, vane pumps, gear pumps, general hydraulic valves, oil cylinders, oil-free pneumatic components and various types of seals has become remarkable. Improve, and can be stable mass production, provide guarantees for all types of host to improve product quality. In addition, certain achievements have also been made in the aspects of CAD, pollution control, and proportional servo technology for hydraulic pneumatic components and systems, and have been used for production. So far, the hydraulic, pneumatic and seal products have a total of about 3,000 varieties and more than 23,000 specifications. Among them, there are about 1,200 types of hydraulic pressure, more than 10,000 specifications (including 60 types of hydrodynamic products, 500 specifications); about 1350 types of pneumatic, more than 8,000 specifications; there are also 350 types of rubber seals, more than 5000 The specifications are now basically able to adapt to the general needs ofvarious types of mainframe products. The matching rate for major equipment sets can reach more than 60%, and a small amount of exports has started.In 1998, the domestic production of hydraulic components was 4.8 million pieces, with sales of about 2.8 billion yuan (of which mechanical systems accounted for 70%); output of pneumatic components was 3.6 million pieces, and sales were about 550 million yuan (including mechanical systems accounting for about 60%) The production of seals is about 800 million pieces, and the sales volume is about 1 billion yuan (including about 50% of mechanical systems). According to the statistics of the annual report of the China Hydraulic and Pneumatic Sealing Industry Association in 1998, the production and sales rate of hydraulic products was 97.5% (101% of hydraulic power), 95.9% of air pressure, and 98.7% of seal. This fully reflects the basic convergence of production and sales.Although China's hydraulic, pneumatic and sealing industries have made great progress, there are still many gaps compared with the development needs of the mainframe and the world's advanced level, which are mainly reflected in the variety, performance and reliability of products. . Take hydraulic products as an example, the product varieties are only 1/3 of the foreign country, and the life expectancy is 1/2 of that of foreign countries. In order to meet the needs of key hosts, imported hosts, and majortechnical equipment, China has a large number of imported hydraulic, pneumatic, and sealing products every year. According to customs statistics and relevant data analysis, in 1998, the import volume of hydraulic, pneumatic and seal products was about 200 million U.S. dollars, of which the hydraulic pressure was about 140 million U.S. dollars, the pneumatics were 30 million U.S. dollars, and the seal was about 0.3 billion U.S. dollars. The year is slightly lower. In terms of amount, the current domestic market share of imported products is about 30%. In 1998, the total demand for hydraulic parts in the domestic market was about 6 million pieces, and the total sales volume was 4 billion yuan; the total demand for pneumatic parts was about 5 million pieces, and the total sales volume was over 700 million yuan; the total demand for seals was about 1.1 billion yuan. Pieces, total sales of about 1.3 billion yuan. (3) Future developments1. The main factors affecting development(1) The company's product development capability is not strong, and the level and speed of technology development can not fully meet the current needs for advanced mainframe products, major technical equipment and imported equipment and maintenance;(2) Many companies have lagged behind in manufacturing process, equipment level and management level, and their sense of quality is not strong, resulting in low level of product performance, unstable quality,poor reliability, and insufficiency of service, and lack of user satisfaction. And trusted branded products;(3) The degree of professional specialization in the industry is low, the power is scattered, the duplication of the low level is serious, the product convergence between the region and the enterprise leads to blind competition, and the prices are reduced each other, thus the efficiency of the enterprise is reduced, the funds are lacking, and the turnover is difficult. Insufficient investment in development and technological transformation has severely restricted the overall level of the industry and its competitive strength.(4) When the degree of internationalization of the domestic market is increasing, foreign companies have gradually entered the Chinese market to participate in competition, coupled with the rise of domestic private, cooperative, foreign-funded, and individual enterprises, resulting in increasing impact on state-owned enterprises. .2. Development trendWith the continuous deepening of the socialist market economy, the relationship between supply and demand in the hydraulic, pneumatic and sealed products has undergone major changes. The seller market characterized by “shortage” has basically become a buyer’s market characterized by “structured surplus”. Replaced by. From the perspective of overall capacity, it is already in a trend of oversupply, and in particular,general low-grade hydraulic, pneumatic and seals are generally oversupply; and like high-tech products with high technological content and high value and high value-added products that are urgently needed by the host, Can not meet the needs of the market, can only rely on imports. After China's entry into the WTO, its impact may be greater. Therefore, during the “10th Five-Y ear Plan” period, the growth of the industry’s output value must not only rely on the growth of quantity. Instead, it should focus on the structural contradiction of the industry and intensify efforts to adjust the industrial structure and product structure. It should be based on the improvement of quality. Product technology upgrades in order to adapt to and stimulate market demand, and seek greater development.2. Hydraulic application on power slide(1) Introduction of Power Sliding TableUsing the binding force curve diagram and the state space analysis method to analyze and study the sliding effect and the smoothness of the sliding table of the combined machine tool, the dynamics of the hydraulic drive system of the sliding table—the self-regulating back pressure regulating system are established. mathematical model. Through the digital simulation system of the computer, the causes and main influencing factors of the slide impact and the motion instability are analyzed. What kind of conclusions can be drawn from those, if we canreasonably design the structural dimensions of hydraulic cylinders and self-regulating back pressure regulators ——The symbols used in the text are as follows:s 1 - flow source, that is, the flow rate of the governor valve outlet;S el —— sliding friction of the sliding table;R - the equivalent viscous friction coefficient of the slide;I 1 - quality of slides and cylinders;12 - self-adjusting back pressure valve core quality;C 1, c 2 - liquid volume without cylinder chamber and rod chamber;C 2 - Self-adjusting back pressure valve spring compliance;R 1, R2 - Self-adjusting back pressure valve damping orifice fluid resistance;R 9 - Self-adjusting back pressure valve valve fluid resistance;S e2——initial pre-tightening force of self-adjusting back pressure valve spring;I 4, I5 - Equivalent liquid sense of the pipeline;C 5, C 6 - equivalent liquid capacity of the pipeline;R 5, R7 - Equivalent liquid resistance of the pipeline;V 3, V4 - cylinder rodless cavity and rod cavity volume;P 3, P4—pressure of the rodless cavity and rod cavity of the cylinder;F - the slide bears the load;V - speed of slide motion;In this paper, the power bond diagram and the state space splitting method are used to establish the system's motion mathematical model, and the dynamic characteristics of the slide table can be significantly improved.In the normal operation of the combined machine tool, the magnitude of the speed of the slide, its direction and the load changes it undergoes will affect its performance in varying degrees. Especially in the process of work-in-process, the unsteady movement caused by the advancing of the load on the slide table and the cyclical change of the load will affect the surface quality of the workpiece to be machined. In severe cases, the tool will break. According to the requirements of the Dalian Machine Tool Plant, the author used the binding force curve diagram and the state space analysis method to establish a dynamic mathematical model of a self-adjusting back pressure and speed adjustment system for the new hydraulic drive system of the combined machine tool slide. In order to improve the dynamic characteristics of the sliding table, it is necessary to analyze the causes and main influencing factors of the impetus and movement of the sliding table. However, it must pass the computer's digital simulation and the final results obtained from the research.(2) Dynamic Mathematical ModelThe working principle diagram of the self-adjusting back pressure speedregulation system of the combined machine tool slide hydraulic drive system is shown in the figure. This system is used to complete the work-cycle-stop-rewind. When the sliding table is working, the three-position four-way reversing valve is in the illustrated position. The oil supply pressure of the oil pump will remain approximately constant under the effective action of the overflow valve, and the oil flow passes through the reversing valve and adjusts the speed. The valve enters the rodless chamber of the cylinder to push the slide forward. At the same time, the pressurized oil discharged from the rod chamber of the cylinder will flow back to the tank through the self-regulating back pressure valve and the reversing valve. During this process, there was no change in the operating status of both the one-way valve and the relief valve. The complex and nonlinear system of the hydraulic drive system of the self-adjusting back pressure governor system is a kind of self-adjusting back-pressure governor system. To facilitate the study of its dynamic characteristics, a simple and reasonable dynamic mathematical model that only considers the main influencing factors is established. Especially important [1][2]. From the theoretical analysis and the experimental study, we can see that the system process time is much longer than the process time of the speed control valve. When the effective pressure bearing area of the rodless cavity of the fuel tank is large, the flow rate at the outlet of the speed control valve is instantaneous. The overshoot is reflected in thesmall change in speed of the slide motion [2]. In order to further broaden and deeply study the dynamic characteristics of the system so that the research work can be effectively performed on a miniature computer, this article will further simplify the original model [2], assuming that the speed control valve is output during the entire system pass. When the flow is constant, this is considered to be the source of the flow. The schematic diagram of the dynamic model structure of this system is shown in Fig. 2. It consists of a cylinder, a sliding table, a self-adjusting back pressure valve, and a connecting pipe.The power bond graph is a power flow graph. It is based on the transmission mode of the system energy, based on the actual structure, and uses the centralized parameters to represent the role of the subsystems abstractly as a resistive element R, a perceptual element I, and a capacitive element. Three kinds of role of C. Using this method, the physical concept of modeling is clear, and combined with the state-space analysis method, the linear system can be described and analyzed more accurately. This method is an effective method to study the dynamic characteristics of complex nonlinear systems in the time domain. According to the main characteristics of each component of the self-adjusting back pressure control system and the modeling rules [1], the power bond diagram of the system is obtained. The upper half of each key in the figure represents the power flow. The two variables that makeup the power are the force variables (oil pressure P and force F) and the flow variables (flow q and velocity v). The O node indicates that the system is connected in parallel, and the force variables on each key are equal and the sum of the flow variables is zero; 1 The nodes represent the series connection in the system, the flow variables on each key are equal and the sum of the force variables is Zero. TF denotes a transformer between different energy forms. The TF subscripted letter represents the conversion ratio of the flow variable or the force variable. The short bar on the key indicates the causal relationship between the two variables on the key. The full arrow indicates the control relationship. There are integral or differential relationships between the force and flow variables of the capacitive and perceptual elements in the three types of action elements. Therefore, a complex nonlinear equation of state with nine state variables can be derived from Fig. 3 . In this paper, the research on the dynamic characteristics of the sliding table starts from the two aspects of the slide's hedging and the smoothness of the motion. The fourth-order fixed-length Runge-Kutta is used for digital simulation on the IBM-PC microcomputer.(3) Slide advanceThe swaying phenomenon of the slide table is caused by the sudden disappearance of the load acting on the slide table (such as drilling work conditions). In this process, the table load F, the moving speed V, and thepressure in the two chambers of the cylinder P3 and P4 can be seen from the simulation results in Fig. 4. When the sliding table moves at a uniform speed under the load, the oil pressure in the rodless cavity of the oil cylinder is high, and a large amount of energy is accumulated in the oil. When the load suddenly disappears, the oil pressure of the cavity is rapidly reduced, and the oil is rapidly reduced. When the high-pressure state is transferred to the low-pressure state, a lot of energy is released to the system, resulting in a high-speed forward impact of the slide. However, the front slide of the sliding table causes the pressure in the rod cavity of the oil cylinder to cause the back pressure to rise, thereby consuming part of the energy in the system, which has a certain effect on the kicking of the slide table. We should see that in the studied system, the inlet pressure of the self-adjusting back pressure valve is subject to the comprehensive effect of the two-chamber oil pressure of the oil cylinder. When the load suddenly disappears, the pressure of the self-adjusting back pressure valve rapidly rises and stably exceeds the initial back pressure value. It can be seen from the figure that self-adjusting back pressure in the speed control system when the load disappears, the back pressure of the cylinder rises more than the traditional speed control system, so the oil in the rod cavity of the cylinder absorbs more energy, resulting in the amount of forward momentum of the slide It will be about 20% smaller than traditionalspeed control systems. It can be seen from this that the use of self-adjusting back-gear speed control system as a drive system slider has good characteristics in suppressing the forward punch, in which the self-adjusting back pressure valve plays a very large role.(4) The smoothness of the slideWhen the load acting on the slide changes periodically (such as in the case of milling), the speed of the slide will have to fluctuate. In order to ensure the processing quality requirements, it must reduce its speed fluctuation range as much as possible. From the perspective of the convenience of the discussion of the problem, assume that the load changes according to a sine wave law, and the resulting digital simulation results are shown in Figure 5. From this we can see that this system has the same variation rules and very close numerical values as the conventional speed control system. The reason is that when the change of the load is not large, the pressure in the two chambers of the fuel tank will not have a large change, which will eventually lead to the self-regulating back pressure valve not showing its effect clearly.(5) Improvement measuresThe results of the research show that the dynamic performance of a sliding table with self-regulating back pressure control system as a drive system is better than that of a traditional speed control system. To reduce the amount of kick in the slide, it is necessary to rapidly increase the backpressure of the rod cavity when the load disappears. To increase the smoothness of the sliding table, it is necessary to increase the rigidity of the system. The main measure is to reduce the volume of oil. From the system structure, it is known that the cylinder has a large volume between the rod cavity and the oil discharge pipe, as shown in Fig. 6a. Its existence in terms of delay and attenuation of the self-regulating back pressure valve function, on the other hand, also reduces the rigidity of the system, it will limit the further improvement of the propulsion characteristics and the smoothness of the motion. Thus, improving the dynamic characteristics of the sliding table can be handled by two methods: changing the cylinder volume or changing the size of the self-regulating back pressure valve. Through the simulation calculation of the structural parameters of the system and the comparison of the results, it can be concluded that the ratio of the volume V4 between the rod cavity and the oil discharge pipe to the volume V3 between the rodless cavity and the oil inlet pipe is changed from 5.5 to 5.5. At 1 oclock, as shown in the figure, the diameter of the bottom end of the self-adjusting back pressure valve is increased from the original 10mm to 13mm, and the length of the damper triangle groove is reduced from the original lmm to 0.7mm, which will enable the front of the slide table. The impulse is reduced by 30%, the transition time is obviously shortened, and the smoothness of the slide motion will also be greatly improved.中文译文液压系统W Arnold1. 绪论液压站称液压泵站,是独立的液压装置。

液压系统设计外文文献翻译附录AHydraulic systemC.J.Sexton,S.M.LewisandC.P.PleaseUniversity of Southampton,UKAbstract:A complete hydraulic system consists of five parts, namely, power components, actuators, control components, auxiliary components (accessories) and hydraulic oil. The function of hydraulic system is to help human work, mainly through the implementation of components into the pressure of rotation or reciprocating movement. Other advantages of the hydraulic system include bi-directional movement, overload protection, and variable speed control. In any of the existing powertrain systems, the hydraulic system also has the largest unit mass power ratio. Seals and seals are an important part of hydraulic equipment. Its reliability and service life is an important index to measure the quality of hydraulic system.Keywords: A power element; an actuating element; a control element; an auxiliary element; hydraulic fluidGenerally, there are only three basic ways to transmit power: electrical, mechanical, and hydraulic. Most applications actually combine the three methods into the most efficient and comprehensive system. In order to reasonably determine which method to take, it is important to understand the salient features of the various methods. For example, the hydraulic system transmits power more economically over a long distance than a mechanical system. The hydraulic system, however, has a shorter transmission distance than the electrical system.Hydraulic transmission there are many outstanding advantages, it is widely used, such as the general industrial use of plastics processing machinery, pressure machinery, engineering machinery, machine tools and other mechanical equipment; application of construction machinery, agricultural machinery, automobile and other metallurgical machinery; iron and steel industry, lifting machinery, a roller adjustment device; control gate device in the water conservancy project, riverbed lifting device, bridges and other operating mechanism; high speed turbine power plant equipment, such as nuclear powerplants; ship deck with crane (winch), bow door, bulkhead valve stern thruster; special technology giant antenna with control devices measurement buoys movements such as rotating stage; military industrial control devices used in artillery ship anti rolling devicesaircraft simulation aircraft retractable landing gear and rudder control device device. Special antenna technology control device, measuring buoy, lifting and rotating stage; military artillery unit, ship antirolling device, flight simulation, device and other equipment for rudder control of landing gear and steering device.The function of hydraulic system is to increase the force by changing the pressure. The quality of a hydraulic system depends on the rationality of the system design, the performance of the system components, the pollution prevention and treatment of the system, and the last point is particularly important. In recent years, China's domestic hydraulic technology has greatly improved, and no longer only the use of foreign hydraulic technology for processing.A complete hydraulic system consists of five parts, namely, power components, actuators, control components, auxiliary components (accessories) and hydraulic oil.The function of the power element is to convert the mechanical energy of the prime mover into the pressure energy of the liquid, the oil pump in the hydraulic system, which provides power to the entire hydraulic system. The structure of hydraulic pumps usually include gear pumps, vane pumps and piston pumps.The actuating elements (such as hydraulic cylinders and hydraulic motors) are used to convert the pressure energy of the fluid into mechanical energy and to drive the load in linear reciprocating or slewing motion.Control elements (i.e. hydraulic valves) control and regulate the pressure, flow, and direction of the liquid in the hydraulic system. According to different control functions, the hydraulic valve can be divided into pressure control valve, flow control valve and directional control valve. Pressure control valves are divided into benefits flow valve (An Quanfa), pressure relief valve, sequence valve, pressure relays etc.; flow control valves including throttle valve, regulating valve, diversion valve; directional control valve includes a one-way valve one-way fluid control valve, shuttle valve, reversing valve, etc.. According to different control methods, the hydraulic valve can be divided into switching control valve, fixed value control valve and proportional control valve.The auxiliary components include oil tank, oil filter, oil pipe and pipe joint, sealing ring, quick change joint, high pressure ball valve, hose assembly, pressure measuring joint, pressure gauge, oil level, oil temperature gauge and so on.Hydraulic oil is the medium of transmission of energy in hydraulic system. There are several kinds of mineral oil, emulsion and synthetic hydraulic oil.The function of hydraulic system is to help human work, mainly throughthe implementation of components into the pressure of rotation or reciprocating movement. Hydraulic principle: it is composed of two different sizes of the cylinder is filled with water or oil. Full of water, known as "hydraulic press", full of oil known as "hydraulic press."". Each of two hydraulic cylinders have a movable piston, if put in the small piston on the pressure, according to Pascal's law, the small piston pressure to the piston through the pressure of liquid, the top of the piston will move long distances. The cross-sectional area of the basic small piston is S1, plus a small piston with a downward force F1. Thus, the pressure on the liquid of the small piston, P=F1/S1, can be transmitted equally in all directions. The pressure through the big piston is also P. If the cross sectional area of the piston is S2, pressure F2=P*S2 P pressure piston upward, the cross-sectional area of the small piston is several times, in addition to the small piston small piston force, there will be great pressure, the hydraulic press for pressing plywood, oil, lifting, forging steel.The secret of the hydraulic system's success and versatility lies in its versatility and ease of operation. Hydraulic power transmission will not be restricted, the geometry of the machine as a mechanical system that in addition, hydraulic system is not limited by the physical properties of materials like electrical system, it is almost no amount of power transfer limit. For example, the performance of an electromagnet by steel magnetic saturation limit, on the contrary, the power of hydraulic system only limited by material intensity.In order to increase productivity, enterprises will increasingly rely on automation, which includes remote and direct control of production operations, processing and material handling. The hydraulic power has become an important part of automation, because it has the following four main advantages:1. convenient control, accurate operation by a joystick and a simple button, the hydraulic system operator can immediately start, stop, speed and can provide arbitrary power, position accuracy of 1/10000 inches of position control. A hydraulic system that causes the pilot to lift and drop the landing gear. When the pilot moves the control valve in one direction, the pressure oil flows into a cavity of the hydraulic cylinder and thus falls.2. force, a hydraulic system without the use of heavy gear, pulley lever can simply and effectively less than an ounce of force amplification, produce hundreds of tons of force output.3. constant or constant torque, hydraulic system can not only provide constant change with speed changing or constant torque, it can drive the mobile object per hour from a few inches to several hundred inches per minute per hour. From a few to thousands of revolutions per minute.4. Simple, safe, economical, and in general, hydraulic systems use fewer moving parts than mechanical or electrical systems, so they are easy to run and maintain. This makes the system compact, safe and reliable. For example, a new type of power steering device for vehicles has been phased out of other types of steering power units, which include manual controlsDirection control valve and distributor. Because the steering component is fully hydraulic, there is no universal joint, bearings, gear reducer and other mechanical connections, which makes the system simple and compact. In addition, only very little input torque can produce control force needed to meet the extremely harsh working conditions. It is very important to the operation of space limitations and need a small steering wheel which is necessary to reduce the occasion, operator fatigue.Other advantages of the hydraulic system include bi-directional movement, overload protection, and variable speed control. In any of the existing powertrain systems, the hydraulic system also has the largest unit mass power ratio.The hydraulic system has three disadvantages:1. because the transmission medium (hydraulic oil) in the course of flow, part of the flow velocity is different, resulting in liquid friction, and at the same time, liquid and pipe wall also friction, this is the hydraulic oil temperature rise reasons. Excessive temperature results in more internal and external leakage and reduces mechanical efficiency. At the same time, the hydraulic oil will expand due to the higher temperature. Resulting in an increase in compressibility so that the operation cannot control transmission very well. Solution: high temperature is the hydraulic system's own problems, can only be the biggest mitigation, can not eradicate. The use of better quality hydraulic oil, hydraulic pipe layout, as far as possible to avoid bending, the use of high-quality pipe and pipe fittings, hydraulic valve.2. the vibration of hydraulic system is one of the weak points. The impact of hydraulic oil in the pipeline on the high speed impact and control valve opening and closing is the cause of system vibration. Strong vibrations can cause system control errors, and can cause errors in some of the more complex, sophisticated devices in the system, leading to system failures. Solution: the hydraulic pipe should be fixed, to avoid sharp bends. In order to avoid frequent flow direction changes can not be avoided, shock absorption measures should be done best. The whole hydraulic system should have good vibration reduction measures, while avoiding the influence of the oscillator outside the system.3. the hydraulic system has internal leakage and external leakage, internal leakage refers to the leakage process occurs in the system, such as leakage of hydraulic piston - cylinder, control valve spool and valve leakage between both sides, such as. Although there is no loss of hydraulic oil, but the leakage, the control action has been determined until the system failure. Disclosure refers to the leakage that occurs between the system and the external environment. Hydraulic oil leaks directly into the environment, and in addition to affecting the working environment, there is not enough power to cause system failure. Hydraulic oil leaking into the environment is also dangerous to fire. Solution: use better quality seals to improve the machining accuracy of the equipment.In hydraulic systems and systems, seals are used to prevent leakage of theworking medium and invasion of foreign dust and foreign matter. A sealed element, that is, a seal. Outside leakage will cause waste of working medium, pollute machine and environment, even cause mechanical malfunction and personal accident of equipment. Leakage can cause a drastic drop in volumetric efficiency of hydraulic systems, resulting in insufficient working pressure and even failure to perform work. The small dust particles in the invading system can cause or aggravate the wear of the friction pairs of hydraulic components, and further lead to leakage.As a result, seals and seals are an important part of hydraulic equipment. Its reliability and service life is an important index to measure the quality of hydraulic system. In addition to the clearance seal, the seal is used to control the clearance between the two adjacent surfaces to be below the minimum clearance required for the sealing liquid to pass. In contact sealing, it is divided into two types: self sealing type and self sealing type (i. e. lip seal).附录B液压系统摘要：一个完整的液压系统由五个部分组成，即动力元件、执行元件、控制元件、辅助元件（附件）和液压油。

Hydraulic SystemThere are only three basic methods of transmitting power: electrical, mechanical, and fluid power. Most applications actually use a combination of the three methods to obtain the most efficient overall system. To properly determine which principle method to use, it is important to know the salient features of each type. For example, fluid systems can transmit power more economically over greater distances than can mechanical types. However, fluid systems are restricted to shorter distances than are electrical systems.Hydraulic power transmission system are concerned with the generation, modulation, and control of pressure and flow, and in general such systems include:1.Pumps which convert available power from the prime mover to hydraulic power at the actuator.2.Valves which control the direction of pump-flow, the level of power produced, and the amount of fluid-flow to the actuators. The power level is determined by controlling both the flow and pressure level.3.Actuators which convert hydraulic power to usable mechanical power output at the point required.4.The medium, which is a liquid, provides rigid transmission and control as well as lubrication of components, sealing in valves, and cooling of the system.5.Connectors which link the various system components, provide power conductors for the fluid under pressure, and fluid flow return to tank (reservoir).6.Fluid storage and conditioning equipment which ensure sufficient quality and quantity as well as cooling of the fluid.Hydraulic systems are used in industrial applications such as stamping presses, steel mills , and general manufacturing , agricultural machines , mining industry , aviation , space technology , deep-sea exploration ,transportation , marinetechnology , and offshore gas petroleum exploration . In short, very few people get through a day of their lives without somehow benefiting from the technology of hydraulics.The secret of hydraulic system’s success and widespread use is its versatility and manageability. Fluid power is not hindered by the geometry of the machine as is the case in mechanical systems. Also, power can be transmitted in almost limitless quantities because fluid systems are not so limited by the physical limitations of materials as are the electrical systems. For example, the performance of an electromagnet is limited by the saturation limit of steel. On the other hand, the power limit of fluid systems is limited only by the strength capacity of the material.Industry is going to depend more and more on automation in order to increase productivity. This includes remote and direct control of production operations, manufacturing processes, and materials handling. Fluid power is the muscle of automation because of advantages in the following four major categories.Ease and accuracy of control. By the use of simple levers and push buttons, the operator of a fluid power systems can readily start, stop, speed up or slow down, and position force which provide any desired horsepower with tolerances as precise as one ten-thousandth of an inch.Multiplication of force. A fluid power system (without using cumbersome gears, pulleys, and levers) can multiply forces simply and efficiently from a fraction of an ounce to several hundred tons of output.Constant force or torque. Only fluid power systems are capable of providing constant force or torque regardless of speed changes. This is accomplished whether the work output moves a few inches per hour, several hundred inches per minute, a few revolutions per hour, or thousands of revolutions per minute.Simplicity, safety, economy. In general, fluid power systems use fewer movingparts than comparable mechanical or electrical systems. Thus, they are simpler to maintain and operate. This, in turn, maximizes safety, compactness, and reliability. For example, a new power steering control designed has made all other kinds of power systems obsolete on many off-highway vehicles. The steering unit consists of a manually operated directional control valve and meter in a single body. Because the sterring unit is fully fluid-linked, mechanical linkages, universal joints, bearings, reduction gears, ect . are eliminated. This provides a simple,compact systems.In addition, very little input torque is required to produce the control needed for the toughest applications. This is important where limitations of control space require a small sterring wheel and it becomes necessary to reduce operator fatigue.Additional benefits of fluid power systems include instantly reversible motion, automatic protection against overloads, and infinitely variable speed control. Fluid power systems also have the highest horsepower per weight ratio of any known power source. In spite of all these highly desirable features of fluid power, it is not a panacea for all power transmission problems. Hydraulic systems also have some drawbacks. Hydraulic oils are messy, and leakage is impossible to completely. Also, most hydraulic oils can cause fires if an oil leak occurs in area of hot equipment. There are only three basic methods of transmitting power: electrical, mechanical, and fluid power. Most applications actually use a combination of the three methods to obtain the most efficient overall system. To properly determine which principle method to use, it is important to know the salient features of each type. For example, fluid systems can transmit power more economically over greater distances than can mechanical types. However, fluid systems are restricted to shorter distances than are electrical systems.Hydraulic power transmission system are concerned with the generation, modulation, and control of pressure and flow, and in general such systems include:Pumps which convert available power from the prime mover to hydraulic power at the actuator.Valves which control the direction of pump-flow, the level of power produced, and the amount of fluid-flow to the actuators. The power level is determined by controlling both the flow and pressure level.Actuators which convert hydraulic power to usable mechanical power output at the point required.The medium, which is a liquid, provides rigid transmission and control as well as lubrication of components, sealing in valves, and cooling of the system.Connectors which link the various system components, provide power conductors for the fluid under pressure, and fluid flow return to tank (reservoir).Fluid storage and conditioning equipment which ensure sufficient quality and quantity as well as cooling of the fluid.Hydraulic systems are used in industrial applications such as stamping presses, steel mills , and general manufacturing , agricultural machines , mining industry , aviation , space technology , deep-sea exploration ,transportation , marine technology , and offshore gas petroleum exploration . In short, very few people get through a day of their lives without somehow benefiting from the technology of hydraulics.The secret of hydraulic system’s success and widespread use is its versatility and manageability. Fluid power is not hindered by the geometry of the machine as is the case in mechanical systems. Also, power can be transmitted in almost limitless quantities because fluid systems are not so limited by the physical limitations of materials as are the electrical systems. For example, the performance of an electromagnet is limited by the saturation limit of steel. On the other hand, the power limit of fluid systems is limited only by the strength capacity of the material.Industry is going to depend more and more on automation in order to increase productivity. This includes remote and direct control of production operations, manufacturing processes, and materials handling. Fluid power is the muscle of automation because of advantages in the following four major categories.1. Ease and accuracy of control. By the use of simple levers and push buttons, the operator of a fluid power systems can readily start, stop, speed up or slow down, and position force which provide any desired horsepower with tolerances as precise as one ten-thousandth of an inch.2. Multiplication of force. A fluid power system (without using cumbersome gears, pulleys, and levers) can multiply forces simply and efficiently from a fraction of an ounce to several hundred tons of output.3. Constant force or torque. Only fluid power systems are capable of providing constant force or torque regardless of speed changes. This is accomplished whether the work output moves a few inches per hour, several hundred inches per minute, a few revolutions per hour, or thousands of revolutions per minute.4. Simplicity, safety, economy. In general, fluid power systems use fewer moving parts than comparable mechanical or electrical systems. Thus, they are simpler to maintain and operate. This, in turn, maximizes safety, compactness, and reliability. For example, a new power steering control designed has made all other kinds of power systems obsolete on many off-highway vehicles. The steering unit consists of a manually operated directional control valve and meter in a single body. Because the sterring unit is fully fluid-linked, mechanical linkages, universal joints, bearings, reduction gears, ect . are eliminated. This provides a simple,compact systems.In addition, very little input torque is required to produce the control needed for the toughest applications. This is important where limitations of controlspace require a small sterring wheel and it becomes necessary to reduce operator fatigue.Additional benefits of fluid power systems include instantly reversible motion, automatic protection against overloads, and infinitely variable speed control. Fluid power systems also have the highest horsepower per weight ratio of any known power source. In spite of all these highly desirable features of fluid power, it is not a panacea for all power transmission problems. Hydraulic systems also have some drawbacks. Hydraulic oils are messy, and leakage is impossible to completely. Also, most hydraulic oils can cause fires if an oil leak occurs in area of hot equipment.液压系统仅有以下三种基本方法传递动力：电气，机械和流体。

(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。