外文翻译--机械设计.doc

Mechanical DesignAbstract: A machine is a combination of mechanisms and other components which transforms, transmits, or utilizes energy, force, or motion for a useful purpose. Examples are engines, turbines, vehicles, hoists, printing presses, washing machines, and movie cameras. Many of the principles and methods of design that apply to machines also apply to manufactured articles that are not true machines, from hub caps and filing cabinets to instruments and nuclear pressure vessels. The term mechanicaldesign is used in a broader sense than machine design to include their design.For some apparatus, the thermal and fluid aspects that determine the requirements of heat, flow path,and volume are separately considered. However, the motior and structural aspects and the provisions for retention and enclosure are considerations in mechanical design. Applications occur in the field of mechanical engineering, and in other engineering fields as well, all of which require mechanical evices, such as switches, cams, valves, vessels, and mixers.keyword: Mechanical Designmechanisms Design Process Tolerance Design processThe design begins from real of or the demand of imagination. The existing instrument may need to take in to improve on the enduring, efficiency,weight, speed or the cost. May need new instrument to complete before function done by person, such as Assemble or maintain. The target is all or partly after making sure, design of the next move is to conceive outline the organization that can complete the function needed and it arranges for this, drawing grass diagram to be worth barehanded biggest,it isnt only one personal record of viewpoint with with others discussion of assistance means, and be suitable for to communicate with own viewpoint particularly, is the stimulant which creates sex way of thinking to still need extensive knowledge concerning parts, because a the set new machine usually from be familiar with of each kind of spareparts reschedule or substitute but become, changed size and material perhaps. Regardless at conceive outline process in still after, a design will carry on a fast or rough calculation or analyze to make sure regulation size and possibility. When some concerning need or can use amount of space of viewpoint assurance after, can start pro rata painting grass diagram. Finally, 1 completed according to the design of the function and the credibility, can make kind machine.lf test satisfied, and if the device wants mass production, will to the first design carry on a certain modification to insure with lower cost mass-produce. Later on several years of make and use a period, design probably because of conceive outline new viewpoint perhaps according to test and experience foundation of further analytical the change shown but change. Sell attraction, customer s satisfaction and manufacturing costs to all have something to do with design, the success which designs ability and engineering investment is closely related. Some design standardsAt this part, someone suggests the attitude of the usage creation carries on of analysis, this kind of analysis can cause a graveness improvement and to back up the product conceive outline with perfect,perhaps the product function is more, more economic and more enduring. Creating the stages needing not is first with independentstage. Although analyze personnel the whole probably irresponsible design, he isn t only the right answer of with problem that can be from the numeral put forward wanting him to resolve only, not only only is give should dint value, the size works to limit perhaps. He can put forward more extensive views, for the purpose of improvement norm or project. Because in the analysis the行ont or the analysis the process,he will acquaint with to equip and its work condition, he is fully placed in a beneficial position which conceives outline to choose a project. Best he can put forward a suggestion change shape to Elimination moment of force or should dint concentration, not allow to set up to have to cut the organization that noodles and excessive dynamic state carry a lotus greatly best is he discards his meticulous of design but is not see a machine discard afterwards. For stiring up to create sex thinking, the suggestion designs a personnel and analytical the personnel use following standard.6 ex-standards are particularly applicable to an analysis personnel,although he may involve to all this 10.1. Create the physical function that sex land utilization need when using combine the control dont need.2. Know practical carry lotus and its importance.3. Consider in advance there is no function carrying a lotus.4. Invent to add to carry a condition more beneficially.5. Provide minimum weight the most beneficial of distribute in response to the dint with rigid.6. Use a basic and square distance calculation a comparison and make size superior to turn.7. Select by examinations material to acquire a function combination.8. At spare parts and integrated spare parts careful choice.9. Modify a function design with the orientation production line and decline low cost10. Consider to make parts accurate to position in the assemble with with each other not interference Mechanical Design The whole machine design is a complicated process. Designing the personnel have to at thus of realm, such as calm down mechanics, kinetics dynamics and material mechanics have good cultivated manners, have to also acquaint with manufacturing material and make a craft in addition. Designing the personnel has to can combine all related facts, carrying on Teaches Wei and creating grass diagram and graphics to cometo deliver the manufacturing request to the car.The square one that any product designs works it an is the material that the choice useds for making each parts. The design personnel of today can get an innumerable. While choosing, function, external appearance,material cost and manufacturing costs of product are all very important. Had to be careful to evaluate the function of material before any calculation.It is necessary a careful calculation with the usefulness of insuring the design. Compute to never appear on the diagram, but from ten various reason be saved. Once the whichever parts loses efficacy, will clear up to do what while designing this defective spare parts at the beginning;And, can acquire an experience document from compute past item. While needing the design for ising similar to, the past record will have a tremendous help.The check of computing(with diagram top size) is the most important. A decimal point s mislaying position can ruin an original and acceptable item. For example, if a person wants to design a bracket that can prop up 100 pounds, but it should can prop up 1000 pounds originally, the result affirmation will fail. The square aspect noodles had to check a check to design again a work.The calculator speaks to is an of great use tool for the staff member,can ease a dull calculation and provide to expand analysis to the existing data. Hand over system to make the calculator assistance design (CAD) with each other according to the calculator function and the calculator lend support to a manufacturing(CAM) to make possible.Pass thus of system, may conceive outline a first step to deliver to beat bore paper to take to used for numeral to process control but need not to draw formal construction diagram.The machine design for the laboratory test, model and kind machine is very helpful. The laboratory provided a lot of build up basic concept need of information, however, can also acquire with them some concerning product Finally,how on the spot would the understanding for working.a design personnel of success should offer the step that the utmost effort keeps up with ages. Will appear new material and produce a method everyday. If painting and design personnels dont acquainting with modern method and material may put out action.A good design personnel should usually read technique periodical to keep up with anew development The engineering work is bad The solid is made sure boundary by its surface boundary. Typical model ground, design a personnel to specify Mr. to call size to a spare parts to make it contented its demand. Actually because of the surface irregular and proper surface rough degree, each spare parts cant make into Mr. to call sizes hasing to allow size to have some varieties can make with insuring repeatedly. But, the variety allowed cant certainly too big with as for make to assemble the function of the piece to become bad. Single the variety allowed by spare parts is called business trip. Business trip this technical term not only is applicable to from the acceptable scope of the parts size ofwith manufacturing craft creation, but also is applicable to a machine or processes of exportation. For example, a give already set number of thepower each pedestals of I. C. engine have variety. Actually, we usually discover this kind of variety model will be a frequency to distribute curve, for example t. The distributes. (call the Gauss distribute again) One of the work which designs a personnel is the variety which specifies size for a spare parts and allows, this value canproduce acceptable function. Spare parts business tripWhen there is no appointed accurate size in the diagram, most organizations all have in general use business trip of being applicable to the size. For process size, in general use business trips maying bea士is 0.5 millimeters. Therefore being specified to 15.0 millimeter scopes of sizes can be of 14.5-15.5 millimeters. Other in general use business trips can be applicable to such as the angle and drill a hole with blunt bore, The casting, the forging, the welded joint and weld the angle etc. situation.Can make reference to the diagram of past or general engineering to practice while giving the appointed business trip of a spare parts. The business trip of typical models ising specified is martial become JSO standard define of range. Give to settle business trip to 1, for example H7/s 6, can use for being studying of spare parts size having 1 set and chart to shoulding of number. Underneath this will give concerning pack into inside bore of the concrete example with the stalk or the pillar form match. The standard match of bore and stalkA standard of the engineering work is the business trip which makes sure a pillar form spare parts, installing for example in a tube form spare parts or bore for corresponding of. perhaps is the stalk which revolves in its inner part to match with of loose be decided by application tightly for example, a wheel gear which positions on the stalk needs to betight of quiet match, here stalk of the diameter compares wheel gear actually of inside path a little bit a little bit big in order to can deliver need of Torque .Furthermore, the diameter of glide bearings has to be big in the diameter of the stalk to make it revolve. On the supposition that speak to can t become the accurate size to the parts manufacturing from the economy, all of the variety of stalk and bore size have to make sure. But, variety of scope shouldn t the too big in order to prevent assemble hour damaged .For being unlikely to there is everlasting drive appointed business trip size endlessly, have already drawn up national and international standard to make sure business trip to take, for example hll/c11.For using this data, gave the definition in the traditional business trip usage. Usually what to use is the Basic hole system, because this meeting makes company internal auger needed, wring knife and pull knife and calculate the decrease of tool category. Size:Mean the number of the size numerical value by appropriation unit.Actual size:The parts size got through a diagraph Size extreme limit:The spare parts allows of biggest with most baby size.The biggest size extreme limit:Bigger in two size extreme limitsMost baby size extreme limit:Smaller in two size extremelimits ofBasic size:Fix the reference size of size extreme limit in order toDeviation:A size with it to should of the algebra of basic size bad .Actual deviation: Actual size with it to should of the algebra of basic size bad.Last deviation:The biggest size extreme limit with it to should of the algebra of basic size badDescend deviation:Most baby size extreme limit with it to should of the algebra of basic size badBusiness trip:The biggest size extreme limit with most the bad value of baby size extreme limit.Stalk:Specifying an exterior characteristics with all partsconsistently uses technical termBore:Specify a parts all internal characteristics to consistently use technical term. The initial design creation satisfies appointed demanding solution. The initial design can represent all sub- systems of constituting the whole system with the total of zero partses.Ion and Smith describe an initial design for is become by a series and evaluate a stage to constitute of an iterative process, each stage matches together to become a good solution. At each iterative stage conceive outline more in detail, can more overall valuation.Produce possibly many of or the economy is convenient of conceive outline and the viewpoint is important. There is 1 kind to lure, let you accept the first hopeful conceive outline and carry on a detailed design until end product. Should resist this kind of come-on, because of so as a result the head quarter is more quite a few. Well worth mentioning BE,or early or late your design would have to with those designs competitions which come from other manufactories, so the creation develop of the thoughts should be careful. Is to them to carry on valuation to combine choice next move after producing viewpoint and conceiving outline the best conceive outline. A kind of valuation method is to use row watch matrix.The matrix constitutes to from a series of standard. conceive outline have to ask for help them to beat a cent. If suitable, the importance of the standard can add power, conceiving outline most in keeping withly will have a tallest total cent. This method provided a built-up valuation technique. and make personal viewpoint that can hardly promote their own absurdity in the team. Produced the solution of first step, the next move was to express them, in order to they ability and all involve total design process of the persons communicate actually, this one step can adopt forms of drawing the grass diagram or 3D models, since but physical model also but the calculator born model. Of the total plan has been completed and calculated to determine solutions for product design compatibility, details of the design phase had been created.中文译文机械设计摘要机器是机构与其他零件的组合，为了有益的用途而转换、传递或利用能量、力或者运动。实例有发动机、涡轮、车辆、卷扬机、印刷机、洗衣机和电影摄影机。许多适用于机器设计的原理和方法也适用于不是真正机器的制成品，从轮毂盖和档案橱柜到仪表和核压力容器。“机械设计”这一术语比“机器设计”更为广义，它包括机器设计。而对于某些仪器，如用以确定热、流动线路和体积的热力以及流体方面的问题要单独考虑。但是，在机械设计时要考虑运动和结构方面的问题以及保存和封装的问题。在机械工程领域以及其他工程领域应用机械设计，都需要诸如开关、凸轮、阀门、容器和搅拌器等机械装置。设计过程 设计始于真正的或想象的需要。现有的仪器可能需要在耐用性、效率、重量、速度或成本上加以改进。可能需要新的仪器来完成以前由人做的功能，如装配或保养。目标或部分的确定后，设计的下一步就是构思能够完成所需功能的机构及其布置，为此徒手画草图价值极大，他不但作为一个人想法的记录和与其他人讨论的辅助手段，而且尤其适于与自己的想法交流，作为创造性思路的兴奋剂还需要有关于部件的广泛知识，因为一台新机器常常由熟知的各种零件重新安排或替换而成，也许改变了尺寸和材料。无论在构思构成中还是直后，一个设计者都会进行快速或粗略的计算或分析以确定一般尺寸和可行性。当这些关于所需或可用空间的想法确定后，可以开始按比例画草图。最后，一项基于功能和可靠性的设计完成了，就可以制造样机了。如果测试满意，而且如果装置需要大量生产，就要对最初的设计进行一定的修改以确保以较低的成本大量生产。在随后几年的制造和使用期间，设计有可能因构思了新想法或者基于测试和经验基础上的进一步分析所显示的改变而改变。销售吸引力、客户满意度和制造成本都与设计有关，设计能力与工程投资的成功密切相关。一些设计准则 在这一部分，有人建议运用创造性的态度进行的分析，这种分析可以引起重大改进以及对备用产品的构思和完善，也许产品功能更多、更经济、更耐用。创造阶段无须是最初和独立的阶段。虽然分析人员可能并不负责整个设计，但是他不仅仅是能从数字上提出要他解决的问题的正确答案，不仅仅是给出应力值、尺寸或者工作限制。他可以提出更广泛的见解，以便改进规范或方案。由于在分析前或分析过程中，他会熟悉装置及其工作条件，他就处于一个构思备选方案的有利位置。最好他能提出建议改变形状来消除力矩或应力集中，而不是允许构建具有大截面和过多动态载荷的机构最好是他报废他的细致的设计而不是后来看到机械报废。为了激发创造性思维，建议设计人员和分析人员使用以下准则。前6条准则尤其适用于分析人员，虽然他可能涉及到所有这10项。1.创造性地利用所需的物理性能并控制不需要的。2.认识实用载荷及其重要性3.预先考虑没有作用的载荷4.发明更有利的加载条件。5.提供最小重量的最有利的应力分布和刚性。6.用基本方程计算比例并使尺寸最优化。7.选取材料以获得性能组合。8.在备件和集成零件间仔细选择。9.修改功能设计以适应生产过程和降低成本。10.考虑装配中使部件精确定位和互不干扰。机械设计 整个机械设计是一个复杂的过程。设计人员必须在这样的领域，如静力学、运动学、动力学和材料力学具有良好的素养，此外，还必须熟悉制造材料和制造工艺。设计人员必须能够组合所有相关的事实，进行训渭、制作草图和制图来把制造要求传递到车间。 任何产品设计的第一步工作之一是选择用于制造每个部件的材料。今天的设计人员可得到无数的。在选择时，产品的功能、外观、材料成本和制造成本都很重要。在任何计算之前必须仔细评估材料的性能。 有必要仔细计算以确保设计的有效性.计算从不出现在图上，而是由十各种原因被存起来。一旦任何一个部件失效，就要弄清楚在最初设计这个有缺陷的零件时做了什么;而且，从对过去的项目的计算中可以获得一份经验文件。当需要类似的设计时，过去的记录会有极大的帮助。 计算(和图上尺寸)的检查最为重要。一个小数点放错位置可以毁掉一个本来可以接受的项目。例如，如果一个人要设计一个能支撑100磅的托架，而它本应该能支撑1000磅，结果肯定会失败。必须检查再检查设计工作的方方面面。 计算机对于工作人员来讲是一个很有用的工具，可以减轻乏味的计算并且对现有数据提供扩展分析。基于计算机性能的交互系统使计算机辅助设计(CAD)和计算机辅助制造(CAM)成为可能。通过这样的系统，就可能把一个初步构思传送到打孔纸带用于数字加工控制而无须绘制正式的施工图。 实验室测试、模型和样机对于机械设计很有帮助。实验室提供了很多建立基本概念所需的信息，然而，还可用它们获得一些关于产品在现场会如何工作的认识。 最后，一个成功的设计人员应尽最大努力跟上时代步伐。每天都会出现新材料和生产方法。绘图和设计人员如果不熟悉现代方法和材料就可能失去作用。一个好的设计人员应经常阅读技术期刊以跟上新的发展。工程工差 固体由其表面边界确定界限。典型地，设计人员给一个零件指定公称尺寸以使其满足其需要。实际上由于表面不规则以及固有的表面粗糙度，各个零件不能重复地做成公称尺寸必须允许尺寸有一些变化以确保能够制造。但是，所允许的变化一定不能太大以至于使装配件的性能变差单个零件所允许的变化称为公差。 公差这一术语不仅适用于山制造工艺产生的部件尺寸的可以接受的范围，而且适用于机械或加工的输出。例如，一个给定型号的内燃机的功率每台都有所变化。实际上，我们常常发现这种变化模型会是频率分布曲线，例如七，态分布(又叫高斯分布)。设计人员的工作之一就是给一个零件指定尺寸和允许的变化，这个值能够产生可以接受的性能。零件公差 当图中没有指定确切尺寸时，大多数组织都有适用于尺寸的通用公差。对于加工尺寸，通用公差可能是士0.5毫米。因此，被指定为15.0毫米的尺寸的范围可以是14.5毫米到15.5毫米之间其他通用公差可以适用于如角度、钻孔和冲孔，铸件、锻件、焊缝和焊角等情形。 在给一个零件指定公差时，可以参考以前的图或一般的工程实践。典型的公差被指定为英武成Jso标准所定义的幅度。对于一个给定公差，比如H7/s6,对于正在研究的零件尺寸就有一组与图表对应的数值可用。下面这段将给出关于装入孔内的轴或柱形配合的具体例子。孔和轴的标准配合 一项标准的工程工作是确定一个柱形零件的公差，比如安装在一个相应的筒形零件或孔内的.或者是在其内部旋转的轴配合的松紧取决于应用例如，一个定位在轴上的齿轮就需要“紧少，的静配合，这里轴的直径实际上比齿轮毅的内径稍微大一些以便能传递所需的扭矩。再者，滑动轴承的直径必须大于轴的直径以使其旋转。假定从经济上讲不能把部件制造成精确的尺寸，轴和孔尺寸上的大小变化就必须确定。但是，变化的范围不应太大以免装配时受损。 为了不至于有无穷无尽的被指定的公差尺寸，已经制定了国家和国际标准确定了公差带，比如hll/cll。为了使用这一资料，给出了传统公差使用中的定义。通常使用的是基孔制，因为这会使公司内部所需的钻头、绞刀、拉刀和计量工具种类的减少。尺寸:以专用单位表示尺寸数字值的数。实际尺寸:通过测量得到的部件尺寸尺寸极限:零件允许的最大和最小尺寸。最大尺寸极限:两个尺寸极限中较大的。最小尺寸极限:两个尺寸极限中较小的基本尺寸:用以固定尺寸极限的参考尺寸偏差:一个尺寸与其对应的基本尺寸的代数差实际偏差:实际尺寸与其对应的基本尺寸的代数差上偏差:最大尺寸极限与其对应的基本尺寸的代数差卜偏差:最小尺寸极限与其对应的基本尺寸的代数差公差:最大尺寸极限与最小尺寸极限的差值。轴:指定个部件所有外部特征的惯用术语孔:指定一个部件所有内部特征的惯用术语 初步设计产生满足指定需求的解决方案。初步设计可以代表组成整个系统的所有子系统和零部件的总和。Ion和Smith把初步设计描述为由一系列形成和评估阶段组成的一个反复的过程，各阶段合在一起形成好的解决方案。在反复的每一阶段，构思更加详细，可以更全面的评估。 产生尽可能多的或经济便利的构思和想法是重要的。有一种诱惑，让你接受第一个有希望的构思并进行详细的设计直到最终产品。应该抵抗这种诱惑，因为这样结果总会更好些。值得一提的是，或早或晚你的设计会不得不与那些来自其他制造商的设计竞争，因此产生研制的思想应谨慎。 产生了想法和构思后，下一步就是对它们进行评估并选择最佳构思.一种评估方法是使用列表矩阵。矩阵由一系列准则组成.构思必须借助它们打分。如果合适，准则的重要性可以加权，最适合的构思会具有最高总分。这一方法提供了组织的评估技术.而且使团队内的个人很难推行他们自己的不合理的想法。 产生了初步的解决方案，下一步就是表达它们，以便它们能与所有涉及总体设计过程的人交流实际上，这一步可以采用绘制草图或三维模型的形式，既可是物理模型也可是计算机生成的模型。到总草图己经完成并进行计算来确定解决方案对于产品设计规范的兼容性时，细节设计阶段的基础就己建立起来了。