机械类英文翻译（推荐）.docx

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1、机械类英文翻译（推荐） STUDY ON SLIPPERS FOR RAW WATER HYDRAULIC AXIAL PISTON PUMPS AND MOTORS 1.Abstract As concerns for environmental compatibility, safetyand hygienic requirements, hydraulic systems using rawwater as preure medium become more and moreattractive.A raw water hydraulic system has many advantag

2、es over conventional oil hydraulic systems,such as: environmentally compatibility, no pollution and no fire hazard, elimination of expensive oils with the aociated problems of contamination, maintenance,storage, handling, elimination of the return hose, and elimination of health hazards, etc.But as

3、a hydraulic medium, raw water has also drawbacks, such as very low viscosity, high vapor preure, lack of lubrication and chemically active nature, etc., that all tend to promote problems of corrosion, wear, cavitation erosion, leakage, and so on, those problems must be overcome in the design and dev

4、elopment of the raw water hydraulic components, especially the selection of materials and design of structure for the friction pairs in raw water hydraulic pumps and motors. The slipper/swashplate pair is one of the very important friction pairs in axial piston pumps and motors.Under the lubrication

5、 of raw water.materials for slipper/swashplate combination should have superior mechanical strength, low friction, resistance to corrosion, abrasion, cavitation erosion and sliding wear, and the structure of the slipper should be suitable for the characteristics of raw water and materials used Based

6、 on authois researches, a new slipper foraxial piston pumps and motors is introduced in this paper.From tests with the slipper/swashplate lest rig, it shows that the new type slipper combined with appropriate swashplate has good tribological characteristics.This slipper can operate with raw water, e

7、ven sea water.The succeful study on slippers will provide good helps for design and development of raw water hydraulic axial piston pumps and motors with higher performance. 2.Introduction The use of water as hydraulic fluid is not new.The first hydraulic machine as a means of transmitting not only

8、energy but also control signals is raw water hydraulic pre that manufactured by Joseph Bramah in 1795, which marks the beginning of the age of modern applied hydraulics.After that almost 100 years raw water was used as hydraulic medium, until the beginning of 20th century the mineral oil began to ta

9、ke the place of raw water.Because of the much better lubrication and anti-corrosi on properbes of mineral oil as compared with raw water and the development of oil resistant sealing materials, oil hydraulics boosted quickly and raw water hydraulics was left behind, gradually acquiring the image of a

10、n obsolete technology. As concerns over safe or environmental iues a number of other hydraulic fluids have been developed over the past decades, such as synthetic base fluids, water base fluids, and vegetable oil base fluids, etc.These fluids have their own advantages and a certain range of applicat

11、ions.For a given application, engineers can make the hydraulic system have satisfactory performance by careful hydraulic fluid choice and system design.However, these hydraulic fluids also have its own shortcomings,so me shortcomings of these fluids are inherent and fatal.No one of these hydraulic f

12、luids can meet the requirements of fire resistance and environmentally protection at the same time, and most of these fluids are very expensive. The re-emergence of using raw water as hydraulic fluid is mainly because of the following reasons. (1) Environmental Protection Requirement Without strict

13、adherence to specific control techniques, it is nearly impoible to eliminate the threat of leakage in hydraulic systems.Industry observers believe that as much as 85% of all hydraulic fluids eventually leave their systems through slow leaks, catastrophic line breaks, or failures of fittings and seal

14、s.The leakage of hydraulic fluids with some toxic chemical additives not only make working conditions mey and unsafe, but also can not be biodegradable and have potential threat to the environment.Raw water has very good environmental compatibility and no pollution; water in the event of leakage eve

15、ntually evaporates without leaving greasy or dirty residuals needs of applications for water hydraulics.The need of new applications is the intrinsic force of re-emergence and development of water hydraulics (2) Requirement of Safety Mineral oil are flammable, its leakage or spilling from systems ma

16、y be result in a fire when in or near heat sources.Water is not flammable and does not present a fire hazard.In some areas, such as steel and gla production, iron making and foundry, injection molding, die casting, nuclear power, coal mining, etc.the requirement of safety is prime, so raw water hydr

17、aulics may be the best choice in the near future (3) Hygienic Requirement In some fields, such as gold mining, food and medicine proceing, water supply industry, etc , where escaping of oil or chemical additives from hydraulic systems can smear the product and damage the quality of manufactured prod

18、uct.Under these conditions, raw water is an ideal preure medium.(4) Economy Requirement Water is available everywhere, needing no purchase, transport, storage, maintenance and disposal costs, so using water instead of mineral oil and other hydraulic fluids may offer tremendous economy.In ambient wat

19、er environment, the system using raw water as hydraulic fluid can be designed as an open circuit.That means the return lines and water reservoir can be eliminated, further more the heater and the cooler of system are no longer needed, so the volume and weight of hydraulic equipment will reduced and

20、the efficiency of system increased.If used underwater, such as in marine engineering, ocean exploration engineering, subsea equipment, underwater operation tools and robots, etc., water hydraulics can automatically counterbalance the water hydrostatic head, this is very important for improving the e

21、fficiency and performance of the hydraulic systems.(5) Need of New Applications Along with the developments of modern science and technologies, many areas with special requirements provide many new opportunities of applications for water hydraulics.Such as fusion reactor equipment in nuclear power e

22、ngineering, marine equipment and robots in ocean exploration engineering, etc，where the fire resistance, hygienic requirement, economy and environmental protection are all considered.Because of higher power density and smaller size of hydraulics than that of other power transmiions, there have urgen

23、t needs of applications for water hydraulics.The need of new applications is the intrinsic force of re-emergence and development of water hydraulics.3.Material Selection The slipper/swashplate pair is one of the very important friction pairs in axial piston pumps and motors.Under the lubrication of

24、raw water,ingenious material selection is neceary.In a typical axial swashplate is stationary piston pump or motor, the swashplate is stationary ; the swashplate angle with the shaft centerline determines the length of the piston stroke (see Fig.1) When using raw water as lubricant,according to raww

25、aters chemically active nature, low viscositylubrication and high vapor preure,more problem should be considered.Firstly, raw water especially seawater is more aggreive , a large number of ions in seawater result in that seawater have much higher electric conductivity and may lead to electrochemistr

26、y erosion.The materials used for slipper and swashplate inevitably suffer aggreive corrosion from raw water , and the materials used for traditional oil hydraulic components will not be suitable here.Secondly, the kinematic viscosity of water at 50 is approximately 0.55cs ,which is le than 1/30 of t

27、he viscosity of a typical mineral oil fluid.The very low viscosity must increase the difficulty of developing hydrodynamic film between slipper and swashplate,and the very small change of waters viscosity with preure means that elastohydrodynamic lubrication with hard materials is unlikely to occur.

28、Hydraulic fluids with additives that aid in the boundary lubrication of contacting surface permit metal-on-metal contact without large amounts of surface damage or wear.Raw water contains on such additives and its lubrication is very poor.The poor lubrication of water is clearly one of its major dta

29、wbacks, and will lead to increase contact fraction and poibly wear of contacting conponents.Indeed it is well documented that wear was the greatest problem experienced by the early users of water based fluids in axial piston pumps.Researches indicate that the elastohydrodynamic film of water is abou

30、t 0.1m thick at 3m/s and 20-60, the elastohydtodynamic film of HWBF is about 0.15m thick at 0.191.27m/s and 23.5.So there are risks as high dry friction and strong wear between slipper and swashplate under the lubrication of raw water.Thirdly, the vapor preure of water is much higher than that of mi

31、neral oil, which means that water boils or vaporizes much easier.Due to waters high vapor preure and high velocity flow caused be waters low viscosity, the slipper and swashplate will be exposed to strong and fast cavitation erosion.So material selection for slipper/swashplate pair should depend on

32、the operation conditions and the special properties of raw water.Materials for slipper/swashplate combination should have superior mechanical strength, low friction, resistance to aggreive corrosion, cavitation erosion,abrasion,and sliding wear, and should be easy available and cost low. 4.Structure

33、 Design The structure design of slipper is very important as well as the material selection. The use of polymers as the material of slipper will derive a new problem-how to make the slipper wrap on the ball-shaped head of piston.Probably the solution is to use corrosion resistant metals combined wit

34、h polymers.The slipper can be divided into two parts.One is slipper pad made of polymer, directly contact on the swashplate, its main function is making the slipper have good tribological properties.The other is shoe made of corrosion resistant alloy, its main function is making the slipper wrap on

35、the ball-shaped head of piston.This structure can take the advantages of both metals ductility and polymers good tribological property(see Fig.2). The main static forces exerted on slipper are show in Fig.3.The force F acted on slipper from piston head includes hydrostatic force Fp on the piston end

36、, spring force Fs, inertia force Fa of piston and slipper, and friction force Ff between piston and cylinder bore as formula: The reaction force N from swashplate can be divided into two components, component Nh of hydrostatic bearing force and component Nm of mechanical surface preure,as following:

37、 N=Nh+Nm The relationship of N and F is: F=Ncos 5.Conclusions Based on authors researches, some conclusions about material selection and structure design of slipper under lubrication of raw water can be summarized as following: (1) Slipper made of polymers combined with swashplate made of corrosion

38、resistant alloys has superior tribological properties.(2) Cotton fiber-filled phenolics can be used to manufacture slipper for a certain application range of operation preure below 14MPa.(3) The spring force exerted on slipper should be strong enough to keep about 0.10.2MPa contacting preuer on the

39、surfaces of slipper and swashplate.Farther tests are underway, and ceramics with good toughne will be introduced to manufacture slipper and swashplate.The experiences of study on slippers will provide good helps for design and development of raw water hydraulic axial piston pumps and motors. Referen

40、ces 1 Joseph L.Foszcz, Hydraulic Fluid Choices, Plant Engineering, (8),1996,68.2Li Zhuangyun, et al, Development of Hydraulic Pump to Operate with Raw water, Proceedings of ASME Fluid Engineering Division Summer Meeting, Washington DC, USA, June 21-25,1998. 关于自然水液压轴向活塞泵和电动机的滑动部分的探讨 1.摘要 基于环境和谐、平安和卫生

41、须要的考虑，液压系统运用自然水作为压力介质这种现象变得越来越广泛。一个自然水液压系统相对于一般的油液压系统有许多优点，例如：环境和谐，没有污染，没有火的危害，与昂贵的油相关的危害、维护、贮存、管理问题的消退，返回塑料管的消退和健康危害的消退等等。但是作为液压系统的介质，自然水也有一些缺点，例如特别低的粘性，很高的水蒸气压力，缺少润滑和化学性自然等等，都加剧了腐蚀、磨损、气蚀侵蚀、泄露等问题，这些问题必需在设计和自然水液压元件的发展，尤其是材料和自然水液压泵和电动机的摩擦部分的结构设计中被克服。 滑动部分/旋转罗盘部分是轴向活塞泵和电动机中的重要摩擦部分。在自然水的润滑下，滑动部分和旋转罗盘结合

42、部分的材料应当较好的机械强度、低摩擦力、腐蚀的反抗性、磨损、气蚀侵蚀和滑动摩擦，并且滑动部分的结构应当对于自然水和运用材料的特性是适合的。 依据作者的探讨，一种新型的用于轴向活塞泵和电动机上的滑块会在这篇文章中介绍。从滑块/旋转罗盘部分试验中表明这种新型的与合适旋转罗盘结合的滑块有着特别好的摩擦特性。这种滑块能够用自然水润滑，甚至是海水也可以。这个关于滑块的探讨将会为自然水液压轴向活塞泵和电动机的更好发展供应好的帮助。 2.介绍 水用来作为液压流体已经不是新技术了。作为转换能源和限制信号的一种方式，第一台液压机器就是自然水液体压力，并且在1795年由杰瑟夫大量生产，同时也标记着现代液压时代的起

43、先。在那之后几乎100年自然水被用作液压介质，直到20世纪的初期，油介质起先取代水介质。和自然水相比，油介质有更好的润滑和矿物油的抗腐蚀性，并且油抗性密封材料，油液压装置发展的很快，自然水液压装置就落后了，慢慢成为一种过时的技术了。 基于在平安和环境问题方面的考虑，很多其他液压流体已经在过去的几十年发展了，例如合成来源液体、水来源液体和蔬菜油来源液体等等。这些液体有着它们各自的优点和确定的用途。对于一种给定的用途，工程师能够通过合理的液压流体选择和系统设计来使液压系统满意这个条件。然而，这些液压流体也存在着自身的缺点，其中的某些缺点是内在的并且是重大的。这些液压流体中没有一种能同时满意防火性和

44、环保性的要求，同时大部分液体是很昂贵的。 运用自然水作为液压流体主要由于以下几个缘由： （1）环境爱护的须要 假如对于特别限制技术没有严格的遵守，评估液压系统中的泄露威逼是不行能的。工业视察员信任全部液压流体中85%的流体最终都是通过缓慢泄露、严峻的连接破损或者设备和密封的故障而离开液压系统的。液压流体和一些有毒的化学添加剂的泄露不仅使工作条件混乱和担心全，同时也不能生物降解和对环境存在潜在的危害。自然水拥有很好的环境适应性并且没有污染；水在泄露后也会消逝而没有油腻和脏的残留物。 （2）平安的须要 矿物油是可燃的，当四周有热源的时候它的泄露可能会导致起火。水是不行燃的，所以不会存在起火隐患。在

45、一些区域，例如钢铁和玻璃生产，钢铁制造和铸造，注射模具，拉模铸造，核动力，采煤等等，对于平安的要求是主要的，因此自然水液压可能会成为将来的最好选择。 （3）液压的须要 在一些领域，例如金矿开采，事物和药品生产，水供应工业等等，这些由于油或者化学添加剂从液压系统中泄露而弄脏产品或是损害大批产品的质量，在这些条件下，自然水是一种志向的压力介质。 （4）经济的须要 水在许多地方都是存在的，不须要购买、运输、贮存、保持和清理成本，因此运用水代替矿物油和其他液压流体可以供应极大的经济性。在包围的水环境中，系统运用自然水作为液压流体能够被设计成开式循环。那意味着返回线和水贮存可以消退，加热和冷却系统也不再

46、须要了，因此液压设备的容积和重量也会削减而系统的效率会增加。假如水下作业，例如在海运的工程上，海洋探究工程，海底设备，水下操作工具和机器人等等，水液压能够自动的抵消水静力的前端，这对于提高效率和液压系统的性能是很重要的。 （5）新应用的须要 随着现代科学和技术的发展，很多有着特别需求的领域为水液压供应了许多运用的机遇。例如在核电工程中的核聚变反应装置，在海洋探究工程中的海运设备和机器人等等，这些地方须要考虑抗燃性，清洁的设备，经济性和环保等方面。和其它的能源转换相比，由于液压系统有较高的力密度和较小的尺寸，所以对于水液压的应用是迫切须要的。新应用的须要是水液压的出现和发展的内在反应。 3材料选

47、择 滑动部分/旋转罗盘部分是轴向活塞泵和电动机中的重要摩擦部分。在自然水的润滑下，奇妙地选择材料是有必要的。 在一个典型的轴向活塞泵或电动机中，旋转罗盘固定不动的，旋转罗盘与轴线的角度确定了活塞盘的长度。 当运用自然水作为润滑剂时，由于自然水的化学活性自然，低粘性，润滑性差和较高的蒸汽压力，所以须要考虑许多问题。 首先，自然水，尤其海水是活性的，海水中的大量离子导致海水有很强的导电性并且会导致电化学腐蚀。用在滑块和旋转罗盘上的材料会不行避开地遭到自然水的活性腐蚀，并且用于传统油液压器件也不适合用在这里。 其次点，水的运动粘性在50时接近0.55cs，少于典型矿物油液体粘性的1/30。过低的粘性

48、肯定会增加发展滑块和旋转罗盘之间水力薄层的困难程度，并且水的粘性伴随着压力的很小改变意味着硬质材料的流体动力润滑是不简单发生的。带有添加剂的液压流体使得金属与金属表面之间没有大量表面破坏或是磨损。自然水不包含如此多的添加剂并且它的润滑性是很差的。水的润滑性差很明显是它的一个主要缺点，并且会导致接触、破裂、和接触器件之间摩擦的加剧。事实上摩擦是早期用水作为轴向活塞泵的流体的运用者遇到的最大问题。探讨表明水的流体弹性动力薄层在3m/s和2060时大约是0.1m厚，HWBF的流体弹性动力薄层在0.191.27m/s和23.5时大约是0.15m厚。因此在自然水润滑下，滑块和旋转罗盘之间有干摩擦和剧烈摩擦时会存在危急。 第三点，水的蒸汽压力要比矿物油的高许多，这意味着水沸腾或是蒸发会更加简单。由于水的高蒸汽压力和高速流淌性由水的粘性地确定的，所以滑块和旋转罗盘会受到剧烈和快速的气穴气蚀损害。 因此，对于滑块和旋转罗盘部分材料的选择应当依据工作条件和自然水的特别性质。滑块和旋转罗盘之间的连接部分应当有很好的机械强度、低摩擦、抗腐蚀性、和气穴气蚀、磨损和滑动摩擦，并且应当有很好的好用性和低成本。 4.结构设计 滑块的结构设计和材料的选择是同样重要的。 用在滑块上的高分子材料会产生一个新的问题，就是怎样使滑块包围住活塞前端的球形部分。其中一个解决方法