机械类外文翻译
机械外文翻译中英文
附录附录1英文原文Rolling Contact BearingsThe concern of a machine designer with ball and roller bearings is fivefold as follows:(a) life in relation to load; (b) stiffness,ie.deflections under load; (c) friction; (d) wear; (e) noise. For moderate loads and speeds the correct selection of a standard bearing on the basis of a load rating will become important where loads are high,although this is usually of less magnitude than that of the shafts or other components associated with the bearing. Where speeds are high special cooling arrangements become necessary which may increase fricitional drag. Wear is primarily associated with the introduction of contaminants,and sealing arrangements must be chosen with regard to the hostility of the environment.Because the high quality and low price of ball and roller bearing depends on quantity production,the task of the machine designer becomes one of selection rather than design. Rolling-contact bearings are generally made with steel which is through-hardened to about 900HV,although in many mechanisms special races are not provided and the interacting surfaces are hardened to about 600HV. It is not surprising that,owing to the high stresses involved,a predominant form of failure should be metal fatigue, and a good deal of work is based on accept values of life and it is general practice in bearing industry to define the load capacity of the bearing as that value below which 90 percent of a batch will exceed life of one million revolutions.Notwithstanding the fact that responsibility for basic design of ball and roller bearings rests with the bearing manufacturer, the machine designer must form a correct appreciation of the duty to be performed by the bearing and be concerned not only with bearing selection but with the conditions for correct installation.The fit of the bearing races onto the shaft or onto the housings is of critical importance because of their combined effect on the internal clearance of the bearing as well as preserving the desired degree of interference fit. Inadequate interference can induce serious trouble from fretting corrosion. The inner race is frequently located axially by against a shoulder. A radius at this point is essential for the avoidance of stress concentration and ball races are provided with a radius or chamfer to follow space for this.Where life is not the determining factor in design, it is usual to determine maximum loadingby the amount to which a bearing will deflect under load. Thus the concept of "static load-carrying capacity" is understood to mean the load that can be applied to a bearing, which is either stationary or subject to slight swiveling motions, without impairing its running qualities for subsequent rotational motion. This has been determined by practical experience as the load which when applied to a bearing results in a total deformation of 0.0025mm for a ball 25mm in diameter.The successful functioning of many bearings depends upon providing them with adequate protection against their environment, and in some circumstances the environment must be protected from lubricants or products of deterioration of the bearing design. Moreover, seals which are applied to moving parts for any purpose are of interest to tribologists because they are components of bearing systems and can only be designed satisfactorily on basis of the appropriate bearing theory.Notwithstanding their importance, the amount of research effort that has been devoted to the understanding of the behavior of seals has been small when compared with that devoted to other aspects of bearing technology.LathesLathes are widely used in industry to produce all kinds of machined parts. Some are general purpose machines, and others are used to perform highly specialized operations.Engine lathesEngine lathes, of course, are general-purpose machine used in production and maintenance shop all over the the world. Sized ranger from small bench models to huge heavy duty pieces of equipment. Many of the larger lathes come equipped with attachments not commonly found in the ordinary shop, such as automatic shop for the carriage.Tracer or Duplicating LathesThe tracer or duplicating lathe is designed o produce irregularly shaped parts automatically. The basic operation of this lathe is as fallows. A template of either a flat or three-dimensional shape is placed in a holder. A guide or pointer then moves along this shape and its movement controls that of the cutting tool. The duplication may include a square or tapered shoulder, grooves, tapers, and contours. Work such as motor shafts, spindles, pistons, rods, car axles, turbine shafts, and a variety of other objects can be turned using this type of lathe.Turret LathesWhen machining a complex workpiece on a general-purpose lathe, a great deal of time isspent changing and adjusting the several tools that are needed to complete the work. One of the first adaptations of the engine lathe which made it suitable to mass production was the addition of multi-tool in place of the tailstock. Although most turrets have six stations, some have as many as eight.High-production turret lathes are very complicated machines with a wide variety of power accessories. The principal feature of all turret lathes, however, is that the tools can perform a consecutive serials of operations in proper sequence. Once the tools have been set and adjusted, little skill is require to run out duplicate parts.Automatic Screw MachineScrew machines are similar in construction to turret lathes, except that their heads are designed to hold and feed long bars of stock. Otherwise, their is little different between them. Both are designed for multiple tooling, and both have adaptations for identical work. Originally, the turret lathe was designed as a chucking lathe for machining small casting, forgings, and irregularly shaped workpieces.The first screw machines were designed to feed bar stock and wire used in making small screw parts. Today, however, the turret lathe is frequently used with a collect attachment, and the automatic screw machine can be equipped with a chuck to hold castings.The single-spindle automatic screw machine, as its name implies, machines work on only one bar of stock at a time. A bar 16 to 20 feet long is feed through the headstock spindle and is held firmly by a collect. The machining operations are done by cutting tools mounted on the cross slide. When the machine is in operation, the spindle and the stock are rotated at selected speeds for different operations. If required, rapid reversal of spindle direction is also possible.In the single-spindle automatic screw machine, a specific length of stock is automatically fed through the spindle to a machining area. At this point, the turret and cross slide move into position and automatically perform whatever operations are required. After the machined piece is cut off, stock is again fed into the machining area and the entire cycle is repeated.Multiple-spindle automatic screw machines have from four to eight spindles located around a spindle carrier. Long bars of stock, supported at the rear of the machine,pass though these hollow spindles and are gripped by collects. With the single spindle machines, the turret indexes around the spindle. When one tool on the turret is working, the others are not. With a multiple spindle machine, however, the spindle itself index. Thus the bars of stock are carried to the various end working and side working tools. Each tool operates in only one position, but tollsoperate simultaneously. Therefore, four to eight workpieces can be machined at the same time.Vertical Turret LathesA vertical turret is basically a turret lathe that has been stood on its headstock end. It is designed to perform a variety of turning operations. It consists of a turret, a revolving table, and a side head with a square turret for holding additional tools. Operations performed by any of the tools mounted on the turret or side head can be controlled through the use of stops.Machining CentersMany of today's more sophisticated lathes are called machining centers since they are capable of performing, in addition to the normal turning operations, certain milling and drilling operations. Basically, a machining center can be thought of as being a combination turret lathe and milling machine. Additional features are sometimes included by the versatility of their machines.Numerical ControlOne of the most fundamental concepts in the area of advanced manufacturing technologies is numerical control(NC). Prior to the advent of NC, all machine tools were manually operated and controlled. Among the many limitations associated with manual control machine tools, perhaps none is more prominent than limitation of operator skills. With manual control, the quality of the product is directly related to and limited to the skills of the operator. Numerical control represents the first major step away from human control of machine tools.Numerical control means the control of machine tools and other manufacturing systems through the use of prerecorded, written symbolic instructions. Rather than operating a machine tool, an NC technician tool to be numerically controlled, it must be interfaced with a device for accepting and decoding the programmed instructions, known as a reader.Numerical control was developed to overcome the limitation of human operators, and it has done so. Numerical control machines are more accurate than manually operated machines, they can produce parts more uniformly, they are faster, and the long-run tooling costs are lower. The development of NC led to the development of several other innovations in manufacturing technology:1.Electrical discharge machining.ser cutting.3. Electron beam welding.Numerical control has also made machines tools more versatile than their manually operated predecessors. An NC machine tool can automatically produce a wide variety of parts, each involving an assortment of widely varied and complex machining processes. Numerical control has allowed manufacturers to undertake the production of products that would not have been feasible from an economic perspective using manually controlled machine tools and processes.Like so many advanced technologies, NC was born in the laboratories of the Masschusetts Institute of Technology. The concept of NC was developed in early 1950s with funding provided by the U.S.Air force. In its earliest stages, NC machines were able to make straight cuts efficiently and effectively.However,curved paths were a problem because the machine tool had to be programmed to undertake a series of horizontal and vertical steps to produce a curve. The shorter is straight lines making up the steps, the smoother is the curve. Each line segment in the steps had to be calculated.This problem led to the development in 1959 of the Automatically Programmed Tools(APT) language. This is a special programming language for NC that uses statements similar to English language to define the part geometry, describe the cutting tool configuration, and specify the necessary motions. The development of the APT language was a major step forward in the further development of NC technology. The original NC systems were vastly different from those used today. The machines had hardwired logic circuits. This instructional programs were written on punched paper, which was later to be replaced by magnetic plastic tape. A tape reader was used to interpret the instructions written on the tape for the machine. Together, all of this represented a giant step forward in the control of machine tools. However, there were a number of problems with NC at this point in its development.A major problem wad the fragility of the punched paper tape medium. It was common for the paper tape containing the programmed instructions to break or tear during a machining process. This problem was exacerbated by the fact that each programmed instructions had to be return through the reader. If it was necessary to produce 100 copies of a given part,it was also necessary to run the paper tape through the reader 100 separate times. Fragile paper tapes simply could not withstand the rigors of a shop floor environment and this kind of repeated use.This led to the development of a special magnetic plastic tape. Whereas the paper tape carried the programmed instructions as a series of holes punched in the tape, the plastic tape carried the instructions as a series of magnetic dots. The plastic tape was much stronger than thepaper taps, which solved the problem of frequent tearing and breakage. However, it still left two other problems.The most important of these was that it was difficult or impossible to change the instructions entered on the tape. To make even the most minor adjustments in a program of instructions, it necessary to interrupt machining operations and make a new tape. It was also still necessary to run the tape through the reader as many times as there were parts to be produced. Fortunately, computer technology became a reality and soon solved the problem of NC associated with punched paper and plastic tape.The development of a concept known as direct numerical control(DNC)solved the paper and plastic tape problems associated with numerical control by simply eliminating tape as the medium for carrying the programmed instructions. In direct numerical control machine tools are tied, via a data transmission link, to a host computer. Programs for operating the machine tools are stored in the host computer and fed to the machine tool as needed via the data transmission linkage. Direct numerical control represented a major step forward over punched tape and plastic tape. However, it is subject to the same limitations as all technologies that depend o a host computer. When the lost computer goes down, the machine tools also experience downtime. This problem led to the development of computer numerical control.The development of the microprocessor allowed for the development of programmable logic controllers(PNC)and microcomputer. These two technologies allowed for the development of computer numerical control(CNC). With CNC, each machine tool has a PLC or a microcomputer that serves the same purpose. This allows programs to be input and stored at each individual machine tool. It also allows programs to be developed off-line and download at the individual machine tool. CNC solved the problems associated with downtime of the host computer, but it introduced another known as data management. The same program might be loaded on ten different being solved by local area networks that connect microcomputer for better data management.CNC machine tool feed motion systems CNC machine tool feed motion systems, especially to the outline of the control of movement into the system, must be addressed to the movement into the position and velocity at the same time the realization of two aspects of automatic control, as compared with the general machine tools, require more feed system high positioning accuracy and good dynamic response.A typical closed-loop control of CNC machine tool feed system, usually by comparing the location of amplification unit, drive unit, mechanical transmission components, such as feedbackand testing of several parts. Here as mechanical gear-driven source refers to the movement of the rotary table into a linear motion of the entire mechanical transmission chain, including the deceleration device, turning the lead screw nut become mobile and vice-oriented components and so on. To ensure that the CNC machine tool feed drive system, precision, sensitivity and stability, the design of the mechanical parts of the general requirement is to eliminate the gap, reducing friction, reducing the movement of inertia to improve the transmission accuracy and stiffness. In addition, the feeding system load changes in the larger, demanding response characteristics, so for the stiffness, inertia matching the requirements are very high.Linear Roller GuidesIn order to meet these requirements, the use of CNC machine tools in general low-friction transmission vice, such as anti-friction sliding rail, rail rolling and hydrostatic guideways, ball screws, etc.; transmission components to ensure accuracy, the use of pre-rational, the form of a reasonable support to enhance the stiffness of transmission; deceleration than the best choice to improve the resolution of machine tools and systems converted to the driveshaft on the reduction of inertia; as far as possible the elimination of drive space and reduce dead-zone inverse error and improve displacement precision.Linear Roller Guides outstanding advantage is seamless, and can impose pre-compression. By the rail body, the slider, ball, cage, end caps and so on. Also known as linear rolling guide unit. Use a fixed guide body without moving parts, the slider fixed on the moving parts. When the slider moves along the rail body, ball and slider in the guide of the arc between the straight and through the rolling bed cover of Rolling Road, from the work load to non-work load, and then rolling back work load, constant circulation, so as to guide and move the slider between the rolling into a ball.附录2中文翻译滚动轴承对于球轴承和滚子轴承，一个机械设计人员应该考虑下面五个方面：（a)寿命与载荷关系；（b）刚度，也就是在载荷作用下的变形；（c）摩擦；（d）磨损；（e）噪声。
机械外文翻译外文文献英文文献机械臂动力学与控制的研究
外文出处：Ellekilde, L. -., & Christensen, H. I. (2009). Control of mobile manipulator using the dynamical systems approach. Robotics and Automation, Icra 09, IEEE International Conference on (pp.1370 - 1376). IEEE.机械臂动力学与控制的研究拉斯彼得Ellekilde摘要操作器和移动平台的组合提供了一种可用于广泛应用程序高效灵活的操作系统,特别是在服务性机器人领域。
在机械臂众多挑战中其中之一是确保机器人在潜在的动态环境中安全工作控制系统的设计。
在本文中,我们将介绍移动机械臂用动力学系统方法被控制的使用方法。
该方法是一种二级方法, 是使用竞争动力学对于统筹协调优化移动平台以及较低层次的融合避障和目标捕获行为的方法。
I介绍在过去的几十年里大多数机器人的研究主要关注在移动平台或操作系统，并且在这两个领域取得了许多可喜的成绩。
今天的新挑战之一是将这两个领域组合在一起形成具有高效移动和有能力操作环境的系统。
特别是服务性机器人将会在这一方面系统需求的增加。
大多数西方国家的人口统计数量显示需要照顾的老人在不断增加,尽管将有很少的工作实际的支持他们。
这就需要增强服务业的自动化程度，因此机器人能够在室内动态环境中安全的工作是最基本的。
图、1 一台由赛格威RMP200和轻重量型库卡机器人组成的平台这项工作平台用于如图1所示,是由一个Segway与一家机器人制造商制造的RMP200轻机器人。
其有一个相对较小的轨迹和高机动性能的平台使它适应在室内环境移动。
库卡工业机器人具有较长的长臂和高有效载荷比自身的重量,从而使其适合移动操作。
当控制移动机械臂系统时,有一个选择是是否考虑一个或两个系统的实体。
在参考文献[1]和[2]中是根据雅可比理论将机械手末端和移动平台结合在一起形成一个单一的控制系统。
机械外文翻译中英文
英文资料Limits and TolerancesThe breakage of the machine spare parts ,generally always from the surface layer beginning of .The function of the product ,particularly its credibility and durable ,be decided by the quantity of spare parts surface layer to a large extent. Purpose that studies the machine to process the surface quantity be for control the machine process medium various craft factor to process the surface quantity influence of regulation, in order to make use of these regulations to control to process the process, end attain to improve the surface quantity, the exaltation product use the function of purpose .The machine processes the surface quantity to use the influence of the function to the machine(A) The surface quantity to bear to whet the sexual influence1.Rough degree of surface to bear to whet the sexual influenceA just process vice-of two contact surfaces of good friction, the first stage is rough only in the surface of the peak department contact ,the actual contact area is much smaller than theoretical contact area, in contact with each other the peak of the units have very great stress, to produce actual contact with the surface area of plastic deformation, deformation and peak between the Department of shear failure, causing serious wear.Parts wear may generally be divided into three stages, the initial stage of wear and tear, normal wear and tear all of a sudden intense phase of stage wear.Parts of the surface roughness of the surface wear big impact. In general the smaller the value of surface roughness, wear better. However, surface roughness value is too small, lubricants difficult to store, contact between the adhesive-prone elements, wear it to increase. Therefore, the surface roughness of a best value, the value and parts of the work related to increased work load, the initial wear increased, the best rough surface is also increased.2.Cold Working hardening the surface of the wear resistanceProcessing the Cold Work hardening the surface of the friction surface layer of metal microhardness increase, it will generally improve the wear resistance. Cold Working but not a higher degree of hardening, wear resistance for the better, because too much will lead to hardening of the Cold Working excessive loose organization ofmetal, even a crack and peeling off the surface of the metal, declined to wear resistance.(B)The surface quality of the impact of fatigue strengthMetal hand alternating loads of fatigue after the damage occurred in parts often Chilled layer below the surface and, therefore parts of the surface quality of fatigue very influential.1.Surface roughness on the impact of fatigue strengthIn alternating load, the surface roughness of the Au-site easily lead to stress concentration, a fatigue crack, the higher the value of surface roughness, surface traces of Yu Shen Wen, Wen at the end of the radius smaller, anti-fatigue damage at the end of the more capacity Worse.2.Residual stress, fatigue Cold Work hardening of the impactResidual stress on the impact of large parts fatigue. Surface layer of residual stress fatigue crack will expand and accelerate the fatigue damage the surface layer and the residual stress can prevent fatigue crack growth, delaying the formation of fatigue damage.(C)The surface quality of the corrosion resistance of the impactParts of the corrosion resistance to a large extent depends on the surface roughness. The higher the value of surface roughness, Au Valley accumulate on the more corrosive substances. Corrosion resistance of the more worse.Surface layer of residual stress will produce stress corrosion cracking, lower parts of the wear-resistance, and the residual stress is to prevent stress corrosion cracking.(D) The surface quality with qualityRough surface will affect the value of the size of the co-ordination with the surface quality. The gap with rough value will increase wear and tear, increased space, with the requirements of the destruction of nature. For Fit, the assembly part of the process of convex surface-crowded peak times, the actual reduction of the surplus and reduce the support of the connection between the strength.DimensioningThe design of a machine includes many factors other than those of determining the loads and stresses and selecting the proper materials. Before construction or manufacture can begin, it is necessary to have complete assembly and detail drawings to convey all necessary information to the shop men. The designer frequently is called upon to check the drawings before they are sent to the shop. Much experience andfamiliarity with manufacturing processes are needed before one can become conversant with all phases of production drawings.Drawings should be carefully checked to see that the dimensioning is done in a manner that will be most convenient and understandable to the production departments. It is obvious that a drawing should be made in such a way that it has one and only one interpretation. In particular, shop personnel should not be required to make trigonometric or other involved calculations before the production machines can be set up.Dimensioning is an involved subject and long experience is required for its mastery.Tolerances must be placed on the dimensions of a drawing to limit the permissible variations in size because it is impossible to manufacture a part exactly to a given dimension. Although small tolerances give higher quality work and a better operating mechanism, the cost of manufacture increases rapidly as the tolerances are reduced, as indicated by the typical curve of Fig 14.1. It is therefore important that the tolerances be specified at the largest values that the operating or functional considerations permit.Tolerances may be either unilateral or bilateral. In unilateral dimensioning, one tolerance is zero, and all the variations are given by the other tolerance. In bilateral dimensioning, a mean dimension is used which extends to the midpoint of the tolerance zone with equal plus and minus variations extending each way from this dimension.The development of production processes for large-volume manufacture at low cost has been largely dependent upon interchangeability of component parts. Thus the designer must determine both the proper tolerances for the individual parts, The manner of placing tolerances on drawings depends somewhat on the kind of product or type of manufacturing process. If the tolerance on a dimension is not specifically stated, the drawing should contain a blanket note which gives the value of the tolerance for such dimensions. However, some companies do not use blanket notes on the supposition that if each dimension is considered individually, wider tolerance than those called for in the note could probably be specified. In any event it is very important that a drawing be free from ambiguities and be subject only to a single interpretation.Dimension and ToleranceIn dimensioning a drawing, the numbers placed in the dimension lines represent dimension that are only approximate and do not represent any degree of accuracy unless so stated by the designer.To specify a degree of accuracy, it is necessary to add tolerance figures to the dimension. Tolerance is the amount of variation permitted in the part or the total variation allowed in a given dimension. A shaft might have a nominal size of 2.5 in. (63.5mm), but for practical reasons this figure could not be maintained in manufacturing without great cost. Hence, a certain tolerance would be added and , if a variation of ±0.003 in.(±0.08mm) could be permitted, the dimension would be stated 2.500±0.003(63.5±0.008mm).Dimensions given close tolerances mean that the part must fit properly with some other part. Both must be given tolerances in keeping with the allowance desired, the manufacturing processes available, and the minimum cost of production and assembly that will maximize profit. Generally speaking, the cost of a part goes up as the tolerance is decreased. If a part has several or more surfaces to be machined, the cost can be excessive when little deviation is allowed from the nominal size.Allowance, which is sometimes confused with tolerance, has an altogether different meaning.It is the minimum clearance space intended between mating parts and representsthe condition of tightest permissible fit. If a shaft, size 1.4980.0000.003+-, is to fit a hole ofsize 1.5000.0030.000+-, the minimum size hole is 1.500 and the maximum size shaft is 1.498.Thus the allowance is 0.002 and the maximum clearance is 0.008 as based on the minimum shaft size and maximum hole dimension.Tolerances may be either unilateral or bilateral. Unilateral tolerance means that any variation is made in only one direction from the nominal or basic dimension.Referring to the previous example, the hole is dimensioned 1.5000.0030.000+-, whichrepresents a unilateral tolerance. If the dimensions were given as 1.500±0.003, the tolerance would be bilateral; that is , it would vary both over and under the nominal dimension. The unilateral system permits changing the tolerance while still retaining the same allowance or type of fit. With the bilateral system, this is not possible without also changing the nominal size dimension of one or both of the two mating parts. In mass production, where mating parts must be interchangeable, unilateral tolerances are customary. To have an interference or fore fit between mating parts, the tolerances must be such as to create a zero or negative allowance.Tolerances Limits and FitsThe drawing must be a true and complete statement of the designer’s expr essed in such a way that the part is convenient to manufacture. Every dimension necessary to define the product must be stated once and repeated in different views. Dimensions relating to one particular feature, such as the position and size of hole, where possible, appear on the same view.There should be no more dimensions than are absolutely necessary, and no feature should be located by more than one dimension in any direction. It may be necessary occasionally to give an auxiliary dimension for reference, possibly for inspection. When this is so, the dimension should be enclosed in a bracket and marked for reference. Such dimensions are not governed by general tolerances.Dimensions that affect the function of the part should always be specified and not left as the sum or other dimensions. If this is not done, the total permissible variation on that dimension will form the sum or difference of the other dimensions and their tolerance, and this with result in these tolerances having to be made unnecessarily tight. The overall dimension should always appear.All dimensions must be governed by the general tolerance on the drawing unless otherwise stated. Usually, such a tolerance will be governed by the magnitude of the dimension. Specific tolerances must always be stated on dimensions affecting or interchangeability.A system of tolerances is necessary to allow for the variations in accuracy that are bound to occur during manufacture, and still provide for interchangeability and correct function of the part.A tolerance is the difference in a dimension in order to allow for unavoidable imperfections in workmanship. The tolerance range will depend on the accuracy of the manufacturing organization, the machining process and the magnitude of the dimension. The greater the tolerance range is disposed on both sides of the nominal dimension. A unilateral tolerance is one where the tolerance zone is on one side only of the nominal dimension, in which case the nominal dimension may from one of the limits.Limits are the extreme dimensions of the tolerance zone. For example, nominal dimension30mm tolerance 30.0230.000++ limits 30.02530.000Fits depend on the relationship between the tolerance zones of two mating parts,and may be broadly classified into a clearance fit with positive allowance, a transition fit where the allowance may be either positive or negative (clearance or interference) , an interference fit where the allowance is always negative.Type of Limits and FitsThe ISO system of Limits and Fits, widely used in a number of leading metric countries, is considerably more complex than the ANSI system.In this system, each part has a basic size. Each limit of part, high and sign being obtained by subtracting the basic size form the limit in question. The difference between the two limits of size of a part is called the tolerance, an absolute without sign.There are three classes of fits: 1) clearance fits, 2) transition fits ( the assembly may have either clearance or interference ), and 3) interference fits .Either a shaft-basis system or a hole-basis system may be used. For any given basic size, a range of tolerance and deviations may be specified with respect to be line of zero deviation, called the zero line. The tolerance is a function of the basic size and is designated by a number symbol, called the grade-thus the tolerance grade. The position of the tolerance with respect to the zero line also a function of the basic size-is indicated by a letter symbol(or two letter), a capital letter for holes and a lowercase letter for shafts. Thus the specification for a hole and shaft having a basic size of 45mm might be45H8/g7.Twenty standard grades of tolerance are provided, called IT 01,IT 0 ,IT 1-18, providing numerical values for each nominal diameter, in arbitrary steps up to 500mm (for example 0-3,3-6,6-10…, 400-500mm). The value of the tolerance unit, I, for grades 5-16 is=+0.0.001i DWhere i is in microns and D in millimeters.Standard shaft and hole deviations similarly are provided by sets of formulas, However, for practical, both tolerances and deviations are provided in three sets of rather complex tables. Additional tables gives the values for basic sizes above 500mm and for “Commonly Used Shafts and Holes” in two categories ---“General Purpose” and “Fine Mecbanisms and Horology”.中文翻译极限与误差机械零件的破坏，一般总是从表层开始的。
不锈钢钢材机械外文文献翻译、中英文翻译、外文翻译
外文原文：Stainless SteelPetro-chemical industry with its own production of some of the features, such as its operating temperature range, low-temperature conditions up to -196 ℃, temperatures can reach more than 500 ℃; operating pressure there is external pressure, vacuum, atmospheric pressure, medium pressure, high pressure, ultra-high pressure (more than 100MPa); In addition, the operating environment in the medium complexity, such as the existence of corrosion, wear and tear, and flammable, explosive, toxic and other solid, gaseous, liquid and a variety of mixed media chloride, sulfide and other salt category. Therefore, the petrochemical industry in the use of stainless steel, the requirements of stainless steel has strong corrosion resistance, including anti-chloride, sulfide and other corrosive salts; resistant to high temperature and low temperature performance. Among them, the petrochemical plant at 500 ~ 600 ℃, the equipment and pipe materials in general to choose a variety of austenitic stainless steel-based, such as 304H, 316,321, such as austenitic stainless steel has been widely used; and for oil exploration, the development of the field of stainless steel with anti-called carbon dioxide, hydrogen sulfide corrosion properties. At present, China's crude oil exploration, development is mainly used in 3Cr, 9Cr, 13Cr, super 13Cr and containing more than Cr22 stainless steel thick-walled, non-magnetic drill collar and drill pipe.At present, China's petrochemical industry in the stainless steel variety of choice, in general to 304 mainly, steel plate thickness of 6 to 22 millimeters, the main polymer used in the construction of storage tanks, heat exchanger shell. In addition, some pieces of the use of reactor tower 316L, TP347, etc., the thickness of 2 ~ 6 mm. Glacial acetic acid and liquid delivery vehicles (train tanker) General use of 304 and 306 plate. In addition, production of the device because of the existence of urea carbamate amine condensate, a highly corrosive, generally stripper, separation, and the use of 316L stainless steel condenser. On the stainless steel clad plate, such plate mainly used in oil refining equipment reaction tower, commonly used for 20R +0 Cr13AL, 16MnR +0 Cr13AL, 20R +0 Cr13 such. Due to the substrate, rehabilitation materials and productionmethods, equipment limitations, domestic composite steel plate thickness, length far from being able to fully meet the demands of the petrochemical industry. In addition, the domestic stainless steel plate splicing, heat treatment, testing and other means yet to be improved.As a result of a wide range of stainless steel, petrochemical industry, currently used for the type of austenitic stainless steel, of which 304 brands of stainless steel plate, tube forgings largest amount, 316,304 L, 316L of the plate, tube, forging a larger amount, ASTM standard TP321, TP347, TP316 brands of boiler tubes, heat exchanger is also gradually increasing dosage. In addition, a special two-way stainless steel as a result of corrosion resistance, Chiang Kai-shek in the petrochemical industry has been rapid promotion and use, of which two-way gradually increasing the amount of stainless steel tubes. At present, China's petrochemical industry in the use of stainless steel is about 70,000 tons, of which stainless steel plate (8 mm or more) the amount of approximately 10,000 tons, stainless steel composite plate is about 15,000 tons, stainless steel seamless steel tube is about 40,000 tons , stainless steel pipe is about5000 tons.Domestic stainless steel in the petrochemical field of application of thereasons for not widespreadAt present, the domestic stainless steel in the petrochemical field of application is not extensive, mainly in the following reasons: First, do not support the issue of standards. China's petrochemical industry has been formed to meet the development needs of the standard system; at home and abroad for high-pressure, high-sulfur, carbon dioxide high "three high" natural gas production equipment, material smelting, manufacturing, testing, testing technology subsidiary norms and standards is still incomplete. Second, product problems. In this regard, mainly stainless steel plate, tube, forging, welding material is not matching. Third, the issue size. Domestic metallurgical industry needs of the petrochemical industry in the thick wide board, large-diameter, thick-walled steel pipe production capacity is very limited. Fourth, quality issues, product qualitystainless steel tube instability. Fifth, research and development problems. New varieties of the domestic stainless steel R & D and production is still unable to meet the petrochemical industry's development needs. Inaddition, the stainless steel research, production and exchange of information between users of the existence of the problem poor. As a result of these factors, the need for stainless steel and petrochemical industries there are many varieties of domestic enterprises can not provide, such as four meters wide of the heavy plate production in China is not yet, there are many forms of stainless steel equipment is imported. In addition, domestic enterprises in product development with foreign enterprises is still lagging behind compared to, for example, some steel companies in Europe every year to launch a dozen new varieties of stainless steel, and Chinese enterprises in this respect, the work is notenough.The five major trends in the petrochemical proposed new requirementsfor stainless steelThe future of China's petrochemical industry will move towards the top five trends in the development of stainless steel products and higherrequirements. First of all, the future of China's oil and gas field exploration and development efforts will further increase. Such as carbon dioxide will be injected back underground ways to reduce carbon dioxide emissions and improve the oil recovery rate. At the same time, China's natural gas exploration and development efforts will be greater than the crude oil exploration and development, and to the high sulfur content, carbon dioxide area development (16% hydrogen sulfide content, carbon dioxide content of about 8%), and will further deepen the depth of wells, land Sham Tseng will exceed the 8000 meters. Second, the petrochemical plant will be large scale. Ethylene production of single device will exceed one million tons; refining single factory refining capacity more than 15 million tons; of purified terephthalic acid (PTA) production capacity of a single plant more than 800,000 tons; stainless steel tanks to the large-scale development. The third is run petrochemical plant will be a long-term development, and gradually overhaul the current cycle of thetransition to 3 years. Fourth, the petrochemical production will diversify the source of materials development. With the improvement of the requirements of environmental protection and energy consumption structure, using natural gas as raw materials of chemical industry is developing rapidly. As a result of natural gas at minus 160 ℃ can be achieved under the conditions of liquefaction, so the need for stainless steel storage and transportation equipment. In addition, as China's LNG imports increase in coastal areas need to receive large-scale construction, working capital and storage facilities, can be expected in this regard will be very large stainless steel consumption.These petrochemical industry development trend of stainless steel products, specifications and varieties have put forward new demands. From anti-corrosion requirements, the petrochemical industry production device temperature, pressure, media are major changes have taken place, stainless steel used in a more harsh environment, anti-corrosion performance by a single change to the composite performance. In the processing performance, the requirements of stainless steel a higher intensity, better toughness, weldability and good processability. In geometry, the requirements of stainless steel products and high precision, width increased, large-diameter steel pipe, steel pipe wall thickness increased. In the standards, stainless steel production as soon as possible with international standards. In addition, the petrochemical industry as a result of each of wells, each set of conditions of service refining device there is a difference, related stainless steel production enterprises should be based on the actual situation in the provision of personalized services. In addition, with the increased usage of stainless steel, stainless steel used in economics is even more important. Therefore, the domestic iron and steel enterprises, especially the steel pipe industry should improve the technological content of products and value-added, high-end product market occupation. At present, many European steel is no longer the production of low value-added oil well pipes, and will focus entirely on high added-tube, the preparation for these high-end products occupied theChinese market. (FocusRecently, China Special Steel Enterprises stainless steel branch of Li Cheng, executive president of the stainless steel industry in talking about China's problems in the development pointed out that the stainless steel to replace imports from the side, although capacity has been able to achieve self-sufficiency, but in fact only part of to replace imports, it is necessary to fully or largely replaced by imports, but also depends on our variety and quality products can meet the various requirements. He also pointed out that the market of fake and shoddy products that seriously endangers the users of stainless steel, it is proposed to increase the relevantdepartments the crackdown.Said Li Cheng, China's stainless steel production capacity from the already self-sufficiency can be achieved, but only a partial substitute for imports. Common market of the four most common grades, namely, 316 and 304 Austenitic. Ferrite 409 and 430, including 304 in the world, accounting for 50 percent of consumption, the use of nearly a hundred years of history. But it is not a single species to the new production of the 304 as an example, in order to meet the varying demands of customers, they will have a brand dozens of varieties, the same as a result of the 304 different varieties in the market price per ton can also be a difference of several hundred dollars to a thousand dollars, we can see the value of a good product, there are markets. This value needs to be done can be. 430 the past two years has developed very rapidly, in fact, this is an in production is not easy to master the varieties, r value of the performance of stamping a crease resistance, it is difficult to achieve, and now the world's more advanced r ≥ 1.2, At a time when there was virtually no punching fold, China and some production plants in both there are still some problems; 409 brands, it seems easier to see the production of components, but it's forming, and welding of the automobile industry to meet the requirements of the development will not be easy.In recent years, the development of China's manufacturing of stainless steel materials for many new requirements, such as power generation, petrochemical, and automobile industries are faced with the newrequirements of the material. Power generation systems need a lot of supercritical required stainless steel pipe, China is now still can not produce, the number of heat exchanger tubes we find it difficult to adapt, petrochemical development needs of some special stainless steel We are also in the trial. Automobile manufacturing, a number of special varieties of high-quality stainless steel requirements, we simply have not yet produced. To meet the needs of users and the use of the industry is necessary to combine joint research, innovation through research in order to solve the problem. In short, we can not just the manufacturingenterprises in the advanced hardware, we are in process technology, smelting technology and the development of both species have a larger gap, attracted the greatest attention to and constantly strive to improve.China's stainless steel market is facing a prominent issue is that the market is flooded with fake and shoddy products. In this regard, Li Cheng pointed out that in recent years because of soaring nickel prices do not appear in accordance with international and domestic standards of the low production of low nickel chromium high manganese so-called "200"series of steel, poor corrosion resistance, in which steel Based on the more serious occurred, the evolution of the market is now known as the "double-free steel" of inferior goods. The so-called double-free is no nickel, non-magnetic, this so-called "double-free" Steel does not have the non-rust and corrosion-resistant properties, which cause great harm to the user at the same time, for the jerry-built illegal producers and sellers the opportunity to bring huge profits, a very serious problem. Another is the emergence of stainless steel decorative tube size and thickness specifications for the production of non-serious "shrink", does not have the necessary stiffness of stainless steel tubes, so all kinds of deception users, to the credibility of stainless steel brought the crisis.At present the country is building a number of major projects, such as the Beijing Olympics and Shanghai World Expo project works, if only to keep the prices down in the tender, it will naturally arise in a cheap fake and shoddy products. Therefore, he called on the community especially the construction of the developers, must be quality-oriented, to avoid allkinds of hidden dangers and accidents to avoid failure and lead to very serious consequences as a result of the material. We should be treated in good faith users of harm to reputation and the interests of consumers of stainless steel act. Suggested that the state departments intensify thecrackdown.Development history::The invention of stainless steel is the world's metallurgical history of a significant achievement. The early 20th century, khazrajiya (LBGuillet) in 1904 -1906 and Porter million (AMPortevin) in 1909-1911 in France; Giessen (W. Giesen) in the years 1907-1909, respectively, in the United Kingdom found Fe - Cr and Fe-Cr-Ni alloy resistance to corrosion.蒙纳尔茨(P. Monnartz) in 1908-1911 in Germany put forward a theory of stainless steel and passivation of the many viewpoints.The inventor of stainless steel for industrial use are: Brearley (H. Brearly) 1912-1913 was developed in the United Kingdom with Cr12% -13% of the martensitic stainless steel; Dan Qi Zeng (C. Dantsizen) 1911-1914 in The United States has developed with Cr14% -16%, C0.07% -0.15% of ferritic stainless steel; Maurer (E. Maurer) and Strauss (B. Strauss) 1912-1914 was developed in Germany with C <1%, Cr15% -40%, Ni <20% of austenitic stainless steel. In 1929, Strauss (B. Strauss) made of low carbon 18-8 (Cr-18%, Ni-8%) stainless steel patent.In order to solve 18-8 steel sensitized state Intergranular corrosion, in1931 Germany's Huo译文：不锈钢石油化工行业生产具有自身的一些特点，例如其操作温度范围宽，低温条件时可达-196℃，高温时可达500℃以上；操作压力有外压、真空、常压、中压、高压、超高压(大于100MPa);此外，操作环境中介质复杂，如存在腐蚀性、磨损性、易燃、易爆、有毒等固态、气态、液态以及各种混合介质氯化物、硫化物和其他盐类。
(完整word版)机械外文翻译外文文献英文文献一个复杂纸盒的包装机器人
附件1：外文资料翻译译文一个复杂纸盒的包装机器人Venketesh N。
Dubey英国设计学院，工程和计算机，伯恩茅斯大学，普尔Jian S。
Dai伦敦大学国王学院，英国伦敦大学，伦敦摘要目的—为了展示设计一种可以折叠复杂几何形状的纸盒的多功能包装机的可行性。
设计/方法/方式—这项研究对各种几何形状的纸盒进行研究,将纸盒分为适当的类型以及机器可以实现的操作;把能加工这些纸盒,并进行机械建模和仿真，且最终可以设计和开发的包装机概念化。
研究结果-这种多功能包装机已经被证明是可能的。
只需将这种多功能包装机小型化，并对它投资以促进其发展，这种机器可以成为现实。
研究限制因素/问题-本研究的目的是证明这种包装机的原理，但实际应用需要考虑结合传感器给出了一个紧凑的、便携式系统。
创意/价值—这项设计是独一无二的，并已被证明可以折叠各种复杂形状的纸盒。
关键字：机器人技术包装自动化文章类型：研究论文1 简介产品包装是关键的工业领域之一，以自动化为首要权益.任何产品流通到消费者手中需要某种形式的包装，无论是食品、礼品或医疗用品。
因此，对高速的产品包装有持续的需求。
对于周期性消费品和精美礼品，这项需求更是大大增加.它们要求包装设计新颖且有吸引力，以吸引潜在客户。
通常这类产品用外观精美、形状复杂的纸盒递送。
如果采用手工方法进行包装,不仅令工人感到乏味且操作复杂,也费时和单调。
对于简单的纸盒包装，通过使用沿传送带布置的专用机器，已经获得了实现。
这些机器只能处理固定类型的纸盒，任何形状和结构的变化很难纳入到系统之中。
在大多数情况下，它们需要进行超过40种变化以适应同种类型但大小不同的纸盒，这就意味着每一个特定类型的纸盒需要一条包装生产线。
从一种类型到另一种类型的纸盒折叠组装生产线的转换将会使资本支出增加。
因为这些限制因素和转换生产线的相关成本,包装的灵活性将会失去。
因此,作为一种补充，手工生产线被引进以适应不同类型的纸盒的生产,从而解决转换生产线的问题.它们承担了大约10％的工作订单，并被用作生产促销产品的组装生产线.但是，问题仍然存在,手工生产线上的管理员和操作工需要一个长时间的学习过程，而且与机器生产线不同，劳动伤害主要是源于扭手动作.此外，手工生产线通常被认为是一个季节性的生产力,仍然需要专门的机器长年运行，以节约成本和时间。
现代包装机械设备毕业课程设计外文文献翻译、中英文翻译
1 英文文献翻译1.1 Modern PackagingAuthor：Abstract1. Changing Needs and New RolesLooking back, historical changes are understandable and obvious. That all of them have had an impact on the way products are brought, consumed and packaged is also obvious. What is not so obvious is what tomorrow will bring. Yet, it is to the needs, markets, and conditions of tomorrow that packaging professionals must always turn their attention.The forces that drove packaging during the Industry Revolution continue to operate today. The consumer society continues to grow and is possibly best described by a 1988s bumper sticker, “Born to Shop”. We consume goods today at a rate 4 to 5 times greater than we did as recently as 1935. Most of these goods are not essential to survival; they constitute what we may call “the good life”.In the second half of the 20th century， the proliferation of goods was so high that packaging was forced into an entirely new role, that of providing the motivation rather than presenting the goods itself. On a shelf of 10 competing products, all of them similar in performance and quality, the only method of differentiating became the package itself. Marketer aimed at lifestyles, emotional values, subliminal images, features, and advantages beyond the basic product rather than the competitor’s. In some in instances, the package has become the product, and occasionally packaging has become entertainment.A brand product to carry the product manufacturer or product sales of theretailer’s label, usually by the buyer as a quality assessment guidance. In some cases, competing brands of product quality is almost no difference, a difference is the sale of its packaging. An interesting visually attractive packaging can give a key marketing advantage and convince impulse spending. However, the packaging should accurately reflect the quality of products/brand value in order to avoid the disappointment of consumers, encourage repeat purchases and build brand loyalty. Ideally, the product should exceed customer expectations.2. Packaging and the Modern Industrial SocietyThe importance of packaging to a modern industrial society is most evident when we examine the food-packaging sector. Food is organic in nature, having an animal or plant source. One characteristic of such organic matter is that, by and large, it has a limited natural biological life.A cut of meat, left to itself, might be unfit for human consumption by the next day. Some animal protein products, such as seafood, can deteriorate within hours.The natural shelf life of plant-based food depends on the species and plant involved. Pulpy fruit portions tend to have a short life span, while seed parts, which in nature have to survive at least separated from the living plant are usually short-lived.In addition to having a limited natural shelf life, most food is geographically and season-ally specific. Thus, potatoes and apples are grown in a few North American geographical regions and harvest during a short maturation period. In a world without packaging，we would need to live at the point of harvest to enjoy these products, and our enjoyment of them would be restricted to the natural biological life span of each. It is by proper storage, packaging and transport techniques that we are able to deliver fresh potatoes and apples, or the products derived from them, throughout the year and throughout the country. Potato-whole,canned, powdered, flaked, chipped, frozen, and instant is available, anytime, anywhere. This ability gives a society great freedom and mobility. Unlike less-developed societies, we are no longer restricted in our choice of where to live, since we are no longer tied to the food-producing ability of an area. Food production becomes more specialized and efficient with the growth of packaging. Crops and animal husbandry are moved to where their production is most economical, without regard to the proximity of a market. Most important, we are free of the natural cycles of feast and famine that are typical of societies dependent on natural regional food-producing cycles.Central processing allows value recovery from what would normally be waste by products of the processed food industry from the basis of other sub-industries. Chicken feathers are high in protein and, properly mill and treated, can be fed back to the next generation of chickens. Vegetable waste is fed to cattle or pigs. Bagasse, the waste cane from sugar pressing, is a source of fiber for papermaking. Fish scales are refined to make additives for paints and nail polish.The economical manufacture of durable goods also depends on good packaging.A product's cost is directly related to production volume. The business drive to reduce costs in the supply chain must be carefully balanced against the fundamental technical requirements for food safety and product integrity, as well as the need to ensure an. efficient logistics service. In addition, there is a requirement to meet the aims of marketing to protect and project brand image through value-added pack design. The latter may involve design inputs that communicate distinctive, aesthetically pleasing, ergonomic, functional and/or environmentally aware attributes. But for a national or international bicycle producer to succeed, it must be a way of getting the product to a market, which may be half a world away. Again, sound packaging, in this case distributionpackaging, is a key part of the system.Some industries could not exist without an international market. For example, Canada is a manufacturer of irradiation equipment, but the Canadian market (which would account for perhaps one unit every several years) could not possibly support such a manufacturing capability. However, by selling to the world, a manufacturing facility becomes viable. In addition to needing packaging for the irradiation machinery and instrumentation, the sale of irradiation equipment requires the sale packaging and transport of radioactive isotopes, a separate challenge in itself. In response to changing consumer lifestyles, the large retail groups and the food service industry development. Their success has been involved in a competition fierce hybrid logistics, trade, marketing and customer service expertise, all of which is dependent on the quality of packaging. They have in part led to the expansion of the dramatic range of products offered, technology innovation, including those in the packaging. Supply retail, food processing and packaging industry will continue to expand its international operations. Sourcing products around the world more and more to assist in reducing trade barriers. The impact of the decline has been increased competition and price pressure. Increased competition led to the rationalization of industrial structure, often in the form of mergers and acquisitions. Packaging, it means that new materials and shapes, increased automation, packaging, size range extension of lower unit cost. Another manufacturer and mergers and acquisitions, the Group's brand of retail packaging and packaging design re-evaluation of the growing development of market segmentation and global food supply chain to promote the use of advanced logistics and packaging systems packaging logistics system is an integral part of, and played an important role in prevention in the food supply or reduce waste generation.3. World Packaging.This discussion has referred to primitive packaging and the evolution of packaging functions. However, humankind's global progress is such that virtually every stage in the development of society and packaging is present somewhere in the world today. Thus, a packager in a highly developed country will agonize over choice of package type, hire expensive marketing groups to develop images to entice the targeted buyer and spend lavishly on graphics. In less-developed countries, consumers are happy to have food, regardless of the package. At the extreme, consumers will bring their own packages or will consume food on the spot, just as they did 2000 years ago.Packagers from the more developed countries sometimes have difficulty working with less-developed nations, for the simple reason that they fail to understand that their respective packaging priorities are completely different. Similarly, developing nations trying to sell goods to North American markets cannot understand our preoccupation with package and graphics.The significant difference is that packaging plays a different role in a market where rice will sell solely because it is available. In the North American market, the consumer may be confronted by five different companies offering rice in 30 or so variations. If all the rice is good and none is inferior, how does a seller create a preference for his particular rice? How does he differentiate? The package plays a large role in this process.The package-intensive developed countries are sometimes criticized for over packaging, and certainly over-packaging does exist. However, North Americans also enjoy the world's cheapest food, requiring only about 11 to 14% of our disposable income. European food costs are about 20% of disposable income, and in the less-developed countries food can take 95%of family income.4. The status and development trend of domestic and international packaging machineryWorldwide, the history of the development of the packaging machinery industry is relatively short, science and technology developed in Europe and America in general started in the 20th century until the 1950s the pace greatly accelerated.From the early 20th century, before the end of World War II World War II，medicine，food, cigarettes，matches，household chemicals and other industrial sectors, the mechanization of the packaging operations; the 1950s, the packaging machine widely used common electric switches and tube for the main components of the control system to achieve the primary automation; 1960s, Electrical and optical liquid-gas technology is significantly increased in the packaging machine, machines to further expand on this basis a dedicated automated packaging line; the 1970s, the micro- electronic technology into the automation of packaging machines and packaging lines, computer control packing production process; from the 1980s to the early 1990s, in some field of packaging, computer, robot application for service, testing and management, in preparation for the over-flexible automatic packaging lines and "no" automatic packaging workshop.Actively promoted and strong co-ordination of all aspects of society, and gradually establish a packaging material, packaging, printing, packaging machinery and other production sectors, and corresponding to the research, design, education, academic, management and organization, and thus the formation of independent and complete. The packaging of light industrial system, and occupies an important place in the national economy as a whole.Based on recent years data that members of the World Packaging Alliance output value of the packaging industry accounts for about 2% of the total output value of the national economy; in which the proportion of packaging machinery, though not large, but the rapid development of an annual average of almost growing at a rate of about 10%. Put into use at the packaging machine is now more than thousand species of packaging joint machines and automated equipment has been stand-alone equate. According to the new technological revolution in the world development trend is expected to packaging materials and packaging process and packaging machinery will be closely related to obtain the breakthrough of a new step, and bring more sectors into the packaging industry.China Packaging Technology Association was established in 1980. Soon, the China National Packaging Corporation have been born. Since then, one after another in the country organized a national and international packaging machinery exhibition, seminars, also published I had the first ever "China Packaging Yearbook and other packaging technology books. All this indicates that China is creating a new packaging historical perio d.1.2中文翻译现代包装1、不断变化的需求和新的角色,回顾以往,包装所带来明显的历史性变化是可以理解的, 一个产品包装方式的给他们的销量带来的影响也是显而易见的。
机械专业外文翻译-挖掘机的机械学和液压学
┊┊┊┊┊┊┊┊┊┊┊┊┊装┊┊┊┊┊订┊┊┊┊┊线┊┊┊┊┊┊┊┊┊┊┊┊┊Multi-Domain Simulation:Mechanics and Hydraulics of an Excavator Abstract It is demonstrated how to model and simulate an excavator with Modelica and Dymola by using Modelica libraries for multi-body and for hydraulic systems. The hydraulic system is controlled by a “load sensing” controller. Usually, models containing3-dimensional mechanical and hydraulic components are difficult to simulate. At hand of the excavator it is shown that Modelica is well suited for such kinds of system simulations.1. IntroductionThe design of a new product requires a number of decisions in the initial phase that severely affect the success of the finished machine. Today, digital simulation is therefore used in early stages to look at different concepts. The view of this paper is that a new excavator is to be designed and several candidates of hydraulic control systems have to be evaluated.Systems that consist of 3-dimensional mechanical and of hydraulic components – like excavators – are difficult to simulate. Usually, two different simulation environments have to be coupled. This is often inconvenient, leads to unnecessary numerical problems and has fragile interfaces. In this article it is demonstrated at hand of the model of an excavator that Modelica is well suited for these types of systems.The 3-dimensional components of the excavator are modeled with the new, free Modelica MultiBody library. This allows especially to use an analytic solution of the kinematic loop at the bucket and to take the masses of the hydraulic cylinders, i.e., the “force elements”, directly into account. The hydraulic part is modeled in a detailed way, utilizing pump, valves and cylinders from HyLib, a hydraulics library for Modelica. For the control part a generic “load sensing” control system is used, modeled by a set of simple equations. This approach gives the required results and keeps the time needed for analyzing the problem on a reasonable level.2. Modeling ChoicesThere are several approaches when simulating a system. Depending on the task it may be necessary to build a very precise model, containing every detail of the system and needing a lot of information, e.g., model parameters. This kind of models is expensive to build up but on the other hand very useful if parameters of a well defined system have to be modified. A typical example is the optimization of parameters of a counterbalance valve in an excavator (Kraft 1996).The other kind of model is needed for a first study of a system. In this case some properties of the pump, cylinders and loads are specified. Required is information about the performance of that system, e.g., the speed of the pistons or the necessary input power at the pump shaft, to make a decision whether this design can be used in principle for the task at hand. This model has therefore to be “cheap”, i.e., it must be possible to build it in a short time without detailed knowledge of particular components.The authors intended to build up a model of the second type, run it and have first results with a minimum amount of time spent. To achieve this goal the modeling language Modelica (Modelica 2002), the Modelica simulation environment Dymola (Dymola 2003), the new Modelica library for 3-dimensional mechanical systems “MultiBody”(Otter et al. 2003) and the Modelica library of hydraulic components HyLib (Beater 2000) was used. The model consists of the 3-dimensional mechanical construction of the excavator, a detailed description of the power hydraulics and a generic “load sensing” controller. This model will be available as a demo in the next version of HyLib.3. Construction of ExcavatorsIn Figure 1 a schematic drawing of a typical excavator under consideration is shown. It consists of a chain track and the hydraulic propel drive which is used to manoeuvre the machine but usually not during a work cycle. On top of that is a carriage where the operator is sitting. It can rotate around a vertical axis with respect to the chain track. It also holds the Diesel engine, the hydraulic pumps and control system. Furthermore, there is a boom, an arm and at the end a bucket which is attached via a planar kinematic loop to the arm. Boom, arm and bucket can be rotated by the appropriate cylinders.┊┊┊┊┊┊┊┊┊┊┊┊┊装┊┊┊┊┊订┊┊┊┊┊线┊┊┊┊┊┊┊┊┊┊┊┊┊Figure 2 shows that the required pressures in the cylinders depend on the position. For the “stretched” situation the pressure in the boom cylinder is 60 % higher than in the retracted position. Not only the position but also the movements have to be taken into account. Figure 3 shows a situation where the arm hangs down. If the carriage does not rotate there is a pulling force required in the cylinder. When rotating –excavators can typically rotate with up to 12 revolutions per minute –the force in the arm cylinder changes its sign and now a pushing force is needed. This change is very significant because now the “active” chamber of the cylinder switches and that must be taken into account by the control system. Both figures demonstrate that a simulation model must take into account the couplings between the four degrees of freedom this excavator has. A simpler model that uses a constant load for each cylinder and the swivel drive leads to erroneous results4. Load Sensing SystemExcavators have typically one Diesel engine, two hydraulic motors and three cylinders. There exist different hydraulic circuits to provide the consumers with the required hydraulic energy. A typical design is a Load Sensing circuit that is energy efficient and user friendly. The idea is to have a flow rate control system for the pump such that it delivers exactly the needed flow rate. As a sensor the pressure drop across an orifice is used. The reference value is the resistance of the orifice. A schematic drawing is shown in figure 4, a good introduction to that topic is given in (anon. 1992).The pump control valve maintains a pressure at the pump port that is typically 15 bar higher than the pressure in the LS line (= Load Sensing line). If the directional valve is closed the pump has therefore a stand-by pressure of 15 bar. If it is open the pump delivers a flow rate that leads to a pressure drop of 15 bar across that directional valve. Note: The directional valve is not used to throttle the pump flow but as a flow meter (pressure drop that is fed back) and as a reference (resistance). The circuit is energy efficient because the pump delivers only the needed flow rate, the throttling losses are small compared to other circuits.If more than one cylinder is used the circuit becomes more complicated, see figure 5. E.g. if the boom requires a pressure of 100 bar and the bucket a pressure of 300 bar the pump pressure must be above 300 bar which would cause an unwanted movement of the boom cylinder. Therefore compensators are used that throttle the oil flow and thus achieve a pressure drop of 15 bar across the particular directional valve. These compensators can be installed upstream or downstream of the directional valves. An additional valve reduces the nominal pressure differential if the maximum pump flow rate or the maximum pressure is reached (see e.g. Nikolaus 1994).5. Model of Mechanical PartIn Figure 6, a Modelica schematic of the mechanical part is shown. The chain track is not modeled, i.e., it is assumed that the chain track does not move. Components “rev1”, ..., “rev4” are the 4 revolute joints to move the parts relative to each other. The icons with the long black line are “virtual”rods that are used to mark specific points on a part, especially the mounting points of the hydraulic cylinders. The light blue spheres (b2, b3, b4, b5) are bodies that have mass and an inertia tensor and are used to model the corresponding properties of the excavator parts.The three components “cyl1f”, “cyl2f”,and “cyl3f” are line force components that describe a force interaction along a line between two attachment points. The small green squares at these components represent 1-dimensional translational connectors from theModelica.Mechanics. Translational library. They are used to define the 1- dimensional force law acting between the two attachment points. Here, the hydraulic cylinders described in the next section are directly attached. The small two spheres in the icons of the “cyl1f,cyl2f, cyl3f” components indicate that optionally two point masses are taken into account that are attached at defined distances from the attachment points along the connecting line. This allows to easily model the essential mass properties (mass and center of mass) of the hydraulic cylinders with only a very small computational overhead.The jointRRR component (see right part of Figure 6) is an assembly element consisting of 3 revolute joints that form together a planar loop when connected to the arm. A picture of this part of an excavator, a zoom in the corresponding Modelica schematic and the animation view is shown in Figure 7. When moving revolute joint “rev4” (= the large red cylinder in the lower part of Figure 7; the small┊┊┊┊┊┊┊┊┊┊┊┊┊装┊┊┊┊┊订┊┊┊┊┊线┊┊┊┊┊┊┊┊┊┊┊┊┊red cylinders characterize the 3 revolute joints of the jointRRR assembly component) the position and orientation of the attachment points of the “left”and “right” revolute joints of the jointRRR component are known. There is a non-linear algebraic loop in the jointRRR component to compute the angles of its three revolute joints given the movement of these attachment points. This non-linear system of equations is solved analytically in the jointRRR object, i.e., in a robust and efficient way. For details see In a first step, the mechanical part of the excavator is simulated without the hydraulic system to test this part separatly. This is performed by attaching translational springs with appropriate spring constants instead of the hydraulic cylinders. After the animation looks fine and the forces and torques in the joints have the expected size, the springs are replaced by the hydraulic system described in the next sections.All components of the new MultiBody library have “built-in” animation definitions, i.e., animation properties are mostly deduced by default from the given definition of the multi-body system. For example, a rod connecting two revolute joints is by default visualized as cylinder where the diameter d is a fraction of the cylinder length L (d = L/40) which is in turn given by the distance of the two revolute joints. A revolute joint is by default visualized by a red cylinder directed along the axis of rotation of the joint. The default animation (with only a few minor adaptations) of the excavator is shown if Figure 8. The light blue spheres characterize the center of mass of bodies. The line force elements that visualize the hydraulic cylinders are defined by two cylinders (yellow and grey color) that are moving in each other. As can be seen, the default animation is useful to get, without extra work from the user side, a rough picture of the model that allows to check the most important properties visually, e.g., whether the center of masses or attachment points are at the expected places.For every component the default animation can be switched off via a Boolean flag. Removing appropriate default animations, such as the “centerof- mass s pheres”, and adding some components that have pure visual information (all visXXX components in the schematic of Figure 6) gives quickly a nicer animation, as is demonstrated in Figure 9. Also CAD data could be utilized for the animation, but this was not available for the examination of this excavator.6. The Hydraulics Library HyLibThe (commercial) Modelica library HyLib (Beater 2000, HyLib 2003) is used to model the pump, metering orifice, load compensator and cylinder of the hydraulic circuit. All these components are standard components for hydraulic circuits and can be obtained from many manufacturers. Models of all of them are contained in HyLib. These mathematical models include both standard textbook models (e. g. Dransfield 1981, Merrit 1967, Viersma 1980) and the most advanced published models that take the behavior of real components into account (Schulz 1979, Will 1968). An example is the general pump model where the output flow is reduced if pressure at the inlet port falls below atmospheric pressure. Numerical properties were also considered when selecting a model (Beater 1999). One point worth mentioning is the fact that all models can be viewed at source code level and are documented by approx. 100 references from easily available literature.After opening the library, the main window is displayed (Figure 10). A double click on the “pumps” icon opens the selection for all components that are needed to originate or end an oil flow (Figure 11). For the problem at hand, a hydraulic flow source with internal leakage and externally commanded flow rate is used. Similarly the needed models for the valves, cylinders and other components are chosen.All components are modeled hierarchically. Starting with a definition of a connector –a port were the oil enters or leaves the component – a template for components with two ports is written. This can be inherited for ideal models, e.g., a laminar resistance or a pressure relief valve. While it usually makes sense to use textual input for these basic models most of the main library models were programmed graphically, i.e., composed from basic library models using the graphical user interface. Figure12 gives an example of graphical programming. All mentioned components were chosen from the library and then graphically connected.7. Library Components in Hydraulics CircuitThe composition diagram in Figure 12 shows the graphically composed hydraulics part of the excavator model. The sub models are chosen from the appropriate libraries, connected and the┊┊┊┊┊┊┊┊┊┊┊┊┊装┊┊┊┊┊订┊┊┊┊┊线┊┊┊┊┊┊┊┊┊┊┊┊┊parameters input. Note that the cylinders and the motor from HyLib can be simply connected to the also shown components of the MultiBody library. The input signals, i.e., the reference signals of the driver of the excavator, are given by tables, specifying the diameter of the metering orifice, i.e. the reference value for the flow rate. From the mechanical part of the excavator only the components are shown in Figure 12 that are directly coupled with hydraulic elements, such as line force elements to which the hydraulic cylinders are attached.8. Model of LS ControlFor this study the following approach is chosen: Model the mechanics of the excavator, the cylinders and to a certain extent the pump and metering valves in detail because only the parameters of the components will be changed, the general structure is fixed. This means that the diameter of the bucket cylinder may be changed but there will be exactly one cylinder working as shown in Figure 1. That is different for the rest of the hydraulic system. In this paper a Load Sensing system, or LS system for short, using one pump is shown but there are other concepts that have to be evaluated during an initial design phase. For instance the use of two pumps, or a separate pump for the swing.The hydraulic control system can be set up using meshed control loops. As there is (almost) no way to implement phase shifting behavior in purely hydraulic control systems the following generic LS system uses only proportional controllers.A detailed model based on actual components would be much bigger and is usually not available at the begin of an initial design phase. It could be built with the components from the hydraulics library but would require a considerable amount of time that is usually not available at the beginning of a project.In Tables 1 and 2, the implementation of the LS control in form of equations is shown. Usually, it is recommended for Modelica models to either use graphical model decomposition or to define the model by equations, but not to mix both descrip- tion forms on the same model level.For the LS system this is different because it has 17 input signals and 5 output signals. One might built one block with 17 inputs and 5 outputs and connect them to the hydraulic circuit. However, in this case it seems more understandable to provide the equations directly on the same level as the hydraulic circuit above and access the input and output signals directly. For example, ”metOri1.port_A.p” used in table 2 is the measured pressure at port_A of the metering orifice metOri1. The calculated values of the LS controller, e.g., the pump flow rate “pump.inPort.signal[1] = ...” is the signal at the filled blue rectangle of the “pump” component, see Figure 12).The strong point of Modelica is that a seamless integration of the 3-dimensional mechanical library, the hydraulics library and the non standard, and therefore in no library available, model of the control system is easily done. The library components can be graphically connected in the object diagram and the text based model can access all needed variables.9. Some Simulation ResultsThe complete model was built using the Modelica modeling and simulation environment Dymola (Dymola 2003), translated, compiled and simulated for 5 s. The simulation time was 17 s using the DASSL integrator with a relative tolerance of 10-6 on a 1.8 GHz notebook, i.e., about 3.4 times slower as real-time. The animation feature in Dymola makes it possible to view the movements in an almost realistic way which helps to explain the results also to non-experts, see Figure 9.Figure 13 gives the reference signals for the three cylinders and the swing, the pump flow rate and pressure. From t = 1.1 s until 1.7 s and from t = 3.6 s until 4.0 s the pump delivers the maximum flow rate. From t = 3.1 s until 3.6 s the maximum allowed pressure is reached. Figure 14 gives the position of the boom and the bucket cylinders and the swing angle. It can be seen that there is no significant change in the piston movement if another movement starts or ends. The control system reduces the couplings between the consumers which are very severe for simple throttling control.Figure 15 shows the operation of the bucket cylinder. The top figure shows the reference trajectory, i. e. the opening of the directional valve. The middle figure shows the conductance of the compensators. With the exception of two spikes it is open from t = 0 s until t = 1 s. This means that in┊┊┊┊┊┊┊┊┊┊┊┊┊装┊┊┊┊┊订┊┊┊┊┊线┊┊┊┊┊┊┊┊┊┊┊┊┊that interval the pump pressure is commanded by that bucket cylinder. After t = 1 s the boom cylinder requires a considerably higher pressure and the bucket compensator therefore increases the resistance (smaller conductance). The bottom figure shows that the flow rate control works fine. Even though there is a severe disturbance (high pump pressure after t = 1 s due to the boom) the commanded flow rate is fed with a small error to the bucket cylinder.10. ConclusionFor the evaluation of different hydraulic circuits a dynamic model of an excavator was built. It consists of a detailed model of the 3 dimensional mechanics of the carriage, including boom, arm and bucket and the standard hydraulic components like pump or cylinder. The control system was not modeled on a component basis but the system was described by a set of nonlinear equations.The system was modeled using the Modelica MultiBody library, the hydraulics library Hylib and a set of application specific equations. With the tool Dymola the system could be build and tested in a short time and it was possible to calculate the required trajectories for evaluation of the control system.The animation feature in Dymola makes it possible to view the movements in an almost realistic way which helps to explain the results also to多畴模拟：挖掘机的机械学和液压学概要：通过使用用于多体和液压系统的Modelica程序库，示范通过Modelica和Dymola如何模拟和仿真挖掘机。
外文翻译---齿轮的设计、制造和应用
毕业设计(论文)外文资料翻译学院：专业：机械设计制造及其自动化姓名：学号：外文出处： Mechanism and Machine Theory34 (1999) 857-876(用外文写)附件： 1.外文资料翻译译文；2.外文原文。
附件1：外文资料翻译译文动力传动圆锥渐开线齿轮的设计、制造和应用Dr. J. Börner,K. Humm,Dr. F. Joachim,Dr. H. akaria,ZF Friedrichshafen AG , 88038Friedrichshafen, Germany；[摘要]圆锥渐开线齿轮(斜面体齿轮)被用于交叉或倾斜轴变速器和平行轴自由侧隙变速器中。
圆锥齿轮是在齿宽横断面上具有不同齿顶高修正(齿厚)的直齿或斜齿圆柱齿轮。
这类齿轮的几何形状是已知的，但应用在动力传动上则多少是个例外。
ZF公司已将该斜面体齿轮装置应用于各种场合:4W D轿车传动装置、船用变速器(主要用于快艇)机器人齿轮箱和工业传动等领域。
斜面体齿轮的模数在0. 7 mm-8 mm之间，交叉传动角在0°- 25°。
之间。
这些边界条件需要对斜面体齿轮的设计、制造和质量有一个深入的理解。
在锥齿轮传动中为获得高承载能力和低噪声所必须进行的齿侧修形可采用范成法磨削工艺制造。
为降低制造成本，机床设定和由于磨削加工造成的齿侧偏差可在设计阶段利用仿真制造进行计算。
本文从总体上介绍了动力传动变速器斜面体齿轮的研发，包括:基本几何形状、宏观及微观几何形状的设计、仿真、制造、齿轮测量和试验。
1前言在变速器中如果各轴轴线不平行的话，转矩传递可采用多种设计，例如:伞齿轮或冠齿轮、万向节轴或圆锥渐开线齿轮(斜面体齿轮)。
圆锥渐开线齿轮特别适用于小轴线角度(小于15°)，该齿轮的优点是在制造、结构特点和输入多样性等方而的简易。
圆锥渐开线齿轮被用于直角或交叉轴传动的变速器或被用于平行轴自由侧隙工况的变速器。
数控车床主轴部件机械外文文献翻译、中英文翻译、外文翻译
数控车床主轴部件机械外文文献翻译、中英文翻译、外文翻译数控车床主轴部件车床是一种主要用于加工旋转表面和平整边缘的机床。
根据使用目的、结构、刀具数量和自动化程度的不同，车床可以分为普通车床、万能车床、转塔车床、立式车床、自动车床和特殊车床。
虽然车床种类繁多，但它们在结构和操作原理上具有共同特性。
普通车床是最常用的代表类型，下面将介绍普通车床的主要部分。
车床床身是车床的主骨架，由两个垂直支柱上的水平横梁组成。
为减振，它通常由灰铸铁或球墨铸铁铸造而成。
车床床身上有导轨，可以让大拖板轻松纵向滑动。
车床床身的高度应适当以方便技师工作。
主轴箱固定在车床床身的左侧，包括轴线平行于导轨的主轴。
主轴通过齿轮箱驱动，齿轮箱可以提供多种不同的速度(通常是6到18速)。
现代车床有些采用无级调速主轴箱，采用摩擦、电力或液压驱动。
主轴往往是中空的，纵向有一通孔，可以通过此孔进给棒料。
同时，此孔为锥形表面，可以安装普通车床顶尖。
主轴外表面是螺纹，可以安装卡盘、花盘或类似的装置。
尾架总成包括底座、尾架体和套筒轴。
底座是能在车床床身上沿导轨滑动的铸件，有定位装置，可以让整个尾架根据工件长度锁定在任何需要位置。
使用手轮和螺杆，与螺杆啮合的是一固接在套筒轴上的螺母。
套筒轴开口端的孔是锥形的，能安装车床顶尖或诸如麻花钻和镗杆之类的工具。
套筒轴通过定位装置能沿着它的移动路径被锁定在任何点。
大拖板的主要功能是安装刀具和产生纵向和/或横向进给。
它实际上是一由车床床身V形导轨引导的、能在车床床身主轴箱和尾架之间滑动的H形滑块。
大拖板可以手动或通过溜板箱和光杆(进给杆)或丝杆(引导螺杆)机动。
本文介绍了在传统普通车床上进行的各种机加工作业。
但是，需要注意的是现代计算机数控车床具有更多的功能，并且可以进行其他操作，例如仿型。
圆柱面车削是所有车床操作中最简单也是最常见的。
工件旋转一整圈产生一个圆心落在车床主轴上的圆；由于刀具的轴向进给运动，这种动作重复许多次。
机械外文翻译文献翻译--消防冲锋舟拖车设计
中文3035字英文原文Fire assault boat trailer designAssault boat special trailer for wood type and wheel type vehicle, galvanized, using high-strengthwear-resistant polyethylene roller, anti-corrosion strong wood and developed a new type of special trailer. trailer with automobile manufacturing technology, equipped with a special fixture of a molding, ensuring the frame and practical aesthetics. One can store 3-5 assault boats, and supporting the use of motor vehicles in the vacuum tire, waterproof wire speed and LED taillight.Assault boat special trailer gather domestic and international various assault boat specifications and models, the use of internationally popular boat design concept, to ensure that the vehicle has reasonable design; with special fixture, ensure the quality of vehicle location; unifies the domestic actual situation, using wood as assault boat bottom bunk, ensure the uniform stress, transportation safety fast, easy to use; with the towing vehicle ( car ) for supporting the vacuum tire, ensure the safety car at high speed.The quality of fire assault boat trailers to product use high safety requirements, whether the processing technology or selection profiles, as well as parts of the selection, have higher requirements, they have such quality control of excellent combination, to ensure fire assault boat trailers and other equipment the use of safety, and to ensure that the rescue personnel life safety.The quality of fire assault boat trailers to the product design flexibility requirements higher, regardless of the specialty of emergency rescue equipment is a comprehensive emergency rescue equipment, as well as a comprehensive professional emergency rescue equipment, only with strong flexibility, to ensure fire punch front boat rescue equipment quickly and accurately the arrival of the first rescue scene, strive for more rescue time, also will have more risks this life, Wei emergency rescue team of professionals to provide reliable safe guard.The quality of fire assault boat trailer for products of professional degree and comprehensive to very high. Professional degree on behalf of the product required to reach a height, a comprehensive representationof the product itself and a plurality of function requirements, and to adapt to a variety of terrain and a varietyof emergency rescue, emergency rescue equipment for the integrated protection provided.Assault boat trailer for automatically loading and unloadingAssault boat trailer for automatically loading and unloading, including for loading assault boat trailer body, is arranged on the trailer body beneath the wheel, is arranged on the trailer body front and transport vehicle for connecting hook, which is characterized in that: the lower part and also includes the trailer body are in rotary connection vertical rod, one end and the vertical rod at the upper end of the first rotating shaft is connected by rail, arranged on the railThe other end for lifting the assault boat lifting mechanism, wherein the vertical rod rotation center along the upper and lower direction, the first shaft center line extends along the horizontal direction,Assault boat trailer for automatically loading and unloading, characterized in that: the trailer body is provided with upward opening slots, wherein the lower end of the vertical rod is inserted in the plug, the lower end of the vertical rod and the slots are arranged between the rotating bear. The rotation of vertical rod which consider revises the plumb direction.Both sides of the trailer body relative to said ground along the up-down direction slide is provided with at least two support frames, the trailer for transport to lose in the first work position and used for loading or unloading of second working position, when the trailer is in the first position, the wheels nadir below the support frame of the nadir, when the trailer is located in the second working position, the wheels of the nadir above the support frame of the nadir, the supporting frame. The trailer body is arranged between the two in the first work position to lock or second working position locking machine Structure. Cross rod and the vertical rod are arranged between the Jacks.The trailer body with the assault boat bottom surfaces that with the support surface, the support are arranged on the surface of silica gel. The lifting mechanism comprises fix on the rail connection, is wound around the connecting part of the traction rope, and attached to the traction cable for the assault boat edge is connected with the two connecting pieces.The two connecting piece is provided with the assault boat edge part matched with the card slot, the slot in the depth direction extends along the horizontal direction.Assault boat trailer for automatically loading and unloading technologyThe utility model relates to an assault boat trailer for automatically loading and unloading.The background technologyIn the existing technology used to transport assault boat trailers, usually includes only used for loading the assault boat trailer body, is arranged on the trailer body beneath the wheel, is arranged on the trailer body in front of the used and the transport vehicle. Take the hook, loaded or unloaded assault boats, need to achieve by crane, operation is troublesome.The utility model contentThe utility model solves the technical problem of providing an assault boat trailer for automatically loading and unloading. In order to solve the technical problem, the technical scheme of the utility model is: a kind of automatic loading and unloading assault boatThe trailer for loading, including assault boat trailer body, is arranged on the trailer body beneath the wheel, is arranged on the .In front of the trailer body for transport vehicle is connected to the lower end of the hook, also included with the trailer body is connected with the vertical rod, one end of the vertical rod and the upper end of the first rotating shaft is connected by rail, arranged on the other end of the transverse rod is used for lifting the assault boat lifting mechanism, wherein the vertical rod rotation center along the upper and lower direction, the first shaft center line extends along the horizontal direction.In some embodiments, the trailer body is provided with upward opening slots, the lower end of the vertical rod is inserted in the slot, the lower end of the vertical rod and the slots are arranged between the rotating bear.Stud rotation centers along the vertical extension.Both sides of the trailer body relative to said ground along the up-down direction slide is provided with at least two support frame, used to transport trailer has the first work position and used for loading or unloading of second working position, when the trailer is in the first position, the wheel nadir below the support frame of the nadir, when the trailer is located in the second working position, the lowest point of the wheel is higher than that of the supporting frame of the nadir, the supporting frame and the trailer body is arranged between the two in the first work position will be locked or articleWorking position locks mechanism.In some embodiments, rod and the vertical rod are arranged between the jacks. The trailer body with the assault boat bottom that surfaces with the support surface, the support were arranged on the surface of silica gel. Easy to include boats under surface is not scratched. The lifting mechanism comprises a fixed on the rail connection.On the connection of the traction rope, connected to the traction cable for the assault boat edge is connected with the two connecting pieces.The two connecting piece is provided with the assault boat edge part matched with the card slot, the slot in the depth direction extends along the horizontal direction. Card slot and the assault boat edge part are matched, thereby increasing the force area, convenient protection boats not deformation.The utility model range, is not limited to the technical characteristics of the particular combination of the technical scheme, and also should be covered by the technical feature or its equivalent features for any combination of the formation of other technical scheme. In the above example features with similar functional technical characteristics are replaced each formed technical schemeThe technical scheme is used, the utility model has the following advantages: through the lift conformation can be assault boat lift, then turning pole, can be loaded or unloaded assault boats carried out, makes the trailer features than multiple, convenient operation.An assault boat trailer for automatically loading and unloading, including for loading assault boat trailer body, is arranged on the trailer body beneath the wheel, is arranged on the trailer body front and transport vehicle for connecting hooks, also consists of a lower part and the trailer body is connected vertical rod, one end of the vertical rod and the upper end of the first rotating shaft is connected by rail, arranged on the transverse rod and the other end of the used for lifting the assault boat lifting mechanism, the lifting mechanism comprises a fixed on the rail connection, around on the connection of the traction rope, attached to the traction cable for the assault boat edge is connected with the two connecting pieces. The two connecting piece is provided with the assault boat edge part matched with the card slot, the slot in the depth direction extends along the horizontal direction.Vertical rod rotation center along the vertical direction, the first shaft center -line extends along the horizontal direction. The trailer body is provided with upward opening slots, the lower end of the vertical rod is inserted in the slot, the lower end of the vertical rod is arranged between the rotary bearing with slots. Both sides of the trailer body relative to said ground along the up-down direction slide is provided with at least two support frame, used to transport trailer has the first work position and used for loading or unloading ofsecond working position, when the trailer is in the first position, the wheels nadir below the support frame the lowest point, when the trailer is located in the second working position, the lowest point of the wheel is higher than that of the branch..Supporting frame for the lowest point, support frame and the trailer body is arranged between the two in the first work position to lock or second working position locking mechanism. The locking mechanism is not the utility model points, as long as it is able to be two phase sliding parts are locked in at least two working position of the locking mechanism can be used here, concrete structure in.Cross rod and the vertical rod are arranged between the jacks. The trailer body with the assault that boats bottom surface with the support surface, the support are arranged on the surface of silica gel. The boats are placed on the supporting surface, the contact between the larger, less force, transport processes in the assault boat more stable.中文翻译消防冲锋舟拖车设计冲锋舟专用拖车分为山木型和滚轮型，整车镀锌、采用高强度耐磨的聚乙烯滚轮、防腐较强的山木而研制的新型专用拖车，拖车采用汽车制造工艺，配备专用的工装夹具一次成型，确保车架实用美观。
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1 A web-based manufacturing service system for rapid product development
Abstract: This paper proposes a novel integrated system of rapid product development based on rapid prototyping, and develops a networked manufacturing service system which offers better support for the rapid product development in small and medium sized enterprises by taking full advantage of the quickly evolving computer network and information technologies. The architecture of the networked manufacturing service system is presented. Furthermore, some of the key issues, including modeling and planning a manufacturing chain, selecting feasible collaborative manufacturers, queuing a manufacturing task, using the synchronously collaborative work environment, and constructing a suitable running platform, are described in detail. Java-enabled solution, together with web techniques, is employed for building such a networked service system. Finally, an actual example is provided illustrating the application of this service system. Keywords：Rapid product development; Rapid prototyping; Service system; Web-based application 1. Introduction This is the era of information technology. Information technology has influenced every realm of society, and dramatically impacted on the traditional industry.Current industries are facing the new challenges:quick response to business opportunity has been considered as one of the most important factors to ensure company competitiveness; manufacturing industry is evolving toward digitalization, network and globalization.In order to respond to the change effectively,manufacturing strategy has to be modified from time to time in accordance with the market situation and customer demand. Any change of strategy should enable manufacturers to be better equipped themselves,with capabilities to cope with demands suchas a faster response to market changes, a shortenedlead time of production, improved quality and speed,the ability to deliver quality 2
products to global customers,and improved communications and transportationsystem [1]. It is an established fact that the useof computers in design and manufacturing constitutesthe most significant opportunity for substantial productivitygain in industry. It has now been widelyaccepted that the future of manufacturing organizationswill be information-oriented, knowledge drivenand much of their daily operations will be automatedaround the global information network that connectseveryone together [2]. In order to meet the demand ofrapid product development, various new technologiessuch as reverse engineering (RE), rapid prototyping (RP), and rapid tooling (RT) have emerged and areregarded as enabling tools with abilities to shorten theproduct development and manufacturing time. Forexample, it has been claimed that RP can cut newproduct development costs by up to 70% and the timeto market by 90% [3]. However, these equipments aretoo expensive for the small and medium sized enterprises(SMEs), and many techniques such as 3D CADsolid modelling, RP process planning, free-form surfacesreconstruction, etc., require the high skilled personnelto complete. Therefore, it is especially difficultfor the SMEs to take full advantage of these technologiesin the product development process. In order tooffer the support of rapid product development fornumerousSMEs,manyRPservice bureaus (SBs)whichcan not only manufacture physical prototype and rapidtooling but also provide other engineering services,have been established. By 2001, there are more than500 SBs all over the world. But not every SB canpossess all design and manufacturing capabilitiesrequired, it must employ effectively the externalresource to better satisfy client requirements. Namely,a virtual enterprise which usually defined as a temporaryalliance of enterprises that come together to sharetheir skills, core competencies, and resource in order tobetter respond to business opportunities, whose cooperationis supported by computer networks [4–6], is tobe founded. Every SBconducts only the tasks of its corecompetencies, and depends on numerous partners tocarry out the remaining tasks that this SB has no such manufacturing capabilities to accomplish in time.While a new thought emphasizing service quality is becoming a basic strategy