机械设计-外文翻译.docx

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1、机械设计 摘要： 机器由机械和其他元件组成的用来转换和传输能量的装置。比如：发动机、涡轮机、车、起重机、印刷机、洗衣机和摄影机。许多机械方面设计的原则和方法也同样适用于非机械方面。术语中的“构造设计”的含义比“机械设计”更加广泛，构造设计包括机械设计。在进行运动分析和结构设计时要把产品的维护和外形也考虑在机械设计中。在机械工程领域中，以及其它工程领域，都需要机械设备，比如：开关、凸轮、阀门、船舶以及搅拌机等。关键词： 设计流程 设计规则 机械设计 设计流程设计开始之前就要想到机器的实用性，现有的机器需要在耐用性、效率、重量、速度，或者成本上得到改善。新的机器必需能够完全或部分代替以前人的功能，

2、比如计算、装配、维修。在设计的初级阶段，应该充分发挥设计人员的创意，不要受到任何约束。即使有一些不切实际的想法，也可以在设计的早期，即在绘制图纸之前被改正掉。只有这样，才不致于阻断创新的思路。通常,必须提出几套设计方案,然后进行比较。很有可能在这个计划最后指定使用某些不在计划方案内的一些想法的计划。一般当产品的外型和组件的尺寸特点已经显现出来的时候，就可以进行全面的设计和分析。接着还要客观的分析机器性能、安全、重量、耐用性，并且成本也要考虑在内。每一个至关重要的部分要优化它的比例和尺寸，同时也要保持与其它组成部分的平衡。选择原材料和工艺的方法。通过力学原理来分析和实现这些重要的特性，如稳定和反

3、应的能量和摩擦力的利用，动力惯性、加速度、能量；包括材料的弹性强度、应力和刚度等物理特性，以及流体的润滑和驱动器的流体力学。设计的过程是一个反复与合作的过程，无论是正式的还是非正式的，对设计者来说每个阶段都很重要。产品设计需要大量的研究和提升。许多的想法,必须通过努力去研究成为一种理念,然后去使用或放弃。虽然每个工程的问题都是不同的,但设计者遵循同样的步骤去解决他们。产品的责任诉讼迫使设计人员和公司在选择材料时，采用最好的方法。在这个过程中，最普遍的五个问题为：（a）不了解或者不使用材料应用方面最好的信息资料；(b)未能预见和考虑材料的合理用途（如可能的话,设计师应进一步预测和考虑因不当使用的

4、产品所造成的后果。在近年来的许多产品责任诉讼案件中，由于错误地使用产品而受到伤害的原告控告生产厂家，并且赢得判决）；(c)所使用的材料的数据不全或是有些数据不确定，尤其是当其性能数据长期不更新；(d)质量控制方法不适当和未经验证；(e)由一些完全不称职的人员选择材料。通过对这五个问题的分析，可以得出这些问题没有充足的存在的理由。对这些问题的研究分析可以为避免此类问题指明方向。尽管采用最好的材料选择方法也不能避免发生产品责任诉讼，设计人员和工业界按照适当的程序进行材料选择，可以大大减少诉讼的数量。从以上的讨论可以看出，选择材料的人应该对材料的性质，特点和加工工艺有一个全面而基本的了解。最后，一个

5、基于功能的设计产品和工程样机会制造出来。如果其测试效果令人满意，那么就会按照初步设计以较低的成本进行批量生产。在随后几年的生产和售后服务中，设计可能要在原有基础上进行新的构思，或者在试验和经验为基础上，进一步分析并改进，以提高产品的市场生存能力。设计规则在这一部分，我们要运用创造性的思维来改进和完善。也许会创造出功能更多、更经济、更耐用的产品。为了激发创造性思维，特提出下列设计和分析的规则。前六个规则对设计者来说特别适用。1. 要有创造性的利用所需要的物理性质和控制过程。2. 认识负载产生的影响及其意义。3. 预测没有想到的负载。4. 创造出更为有利的条件。5. 提供良好的应力分布和最小的重量

6、。6. 运用最基本的方程来优化比例和尺寸。7. 选择合成材料。8. 仔细选择所需的材料和组件。9. 调整功能的设计方案，以适应生产过程并降低成本。10. 提供准确的位置为组件安装时不干涉。机械设计包括以下内容：1 对设计过程、设计所需要公式以及安全系数进行介绍。2 综述了材料的性质、静态和动态载荷分析，包括梁、振动和冲击载荷。3 综述了应力的基本规律和失效分析。4 介绍静态失效理论和静态载荷下机械断裂分析。5 介绍疲劳失效理论并强调在压力条件下接近高循环的疲劳设计，这通常用在旋转机 械的设计中。6 深入探讨机械磨损机理、表面接触应力和表面疲劳现象。7 使用疲劳分析技术校核轴的设计。8 讨论润滑

7、油膜与滚动轴承的理论和应用。9 深入介绍直齿圆柱齿轮的动力学、设计和应力分析，并简单介绍斜齿轮、锥齿轮和涡轮有关方面的问题。10 讨论弹簧设计、螺杆等紧固件的设计，包括传动螺杆和预紧固件。11 介绍盘式和鼓式离合器以及制动器的设计和技术说明。机械设计完整的机械设计是一个复杂的过程。这是一项创造性的工作。项目工程师不仅要有创造性，还必须在机械制图、运动学、工程材料、材料力学和机械制造工艺学等方面具有深厚的基础知识。设计的第一步就是选择产品每个部分的构成材料。许多的材料被今天的设计师所使用是因为这对产品的功能，外观、成本、制造的成本十分重要的。因此对材料的特性必须作出仔细的评估。仔细精确的计算是必

8、要的，以确保设计的有效性。在任何失败的情况下，最好知道在最初设计中有有缺陷的部件。计算（图纸尺寸）检查是非常重要的。一个小数点的位置放错，就可以导致一个本可以完成的项目失败。设计工作的各个方面都应该检查和复查。计算机是一种工具，它能够帮助设计师减轻繁琐的计算，并对现有数据提供进一步的分析。交互系统是基于计算机的能力，已经使计算机辅助设计（CAD）和计算机辅助制造（CAM）成为了可能。应用专家经常谈论如何使人们适应机器。设计人员的基本职责是努力使机器来适应人们。这并不是一项容易的工作，因为实际上并不存在着一个对所有人来说都是最优的操作范围和操作过程。另一个重要问题，设计师必须能够同其他有关人员进

9、行交流和沟通。在设计初级阶段，设计人员必须就初步设计同管理人员进行交流和沟通，并达成共识。这一般是通过口头讨论，草图和文字材料进行的。如前所诉，机械设计的目的是生产能够满足人类需求的产品。发明、发现和技术本身并不一定能给人类带来好处，只有当它们被应用在产品上才能产生效益。因而，应该认识到在一个特定的产品进行设计之前，必须先确定人们是否需要这种产品。应当把机械设计看成是机械设计人员运用创造性的才能进行产品设计、系统分析和制定产品的制造工艺学的一个良机。掌握工程基础知识要比熟记一些数据和公式更为重要。仅仅使用数据和公式是不足以在一个好的设计中做出所需的全部决定的。另一方面，应该认真精确的进行所有运

10、算。例如，即使将一个小数点的位置放错，也会使正确的设计变成错误的。一个好的设计人员应该勇于提出新的想法，而且愿意承担一定的风险，当新的方法不适用时，就使用原来的方法。因此，设计人员必须要有耐心，因为所花费的时间和努力并不能保证带来成功。一个全新的设计，要求屏弃许多陈旧的，为人们所熟知的方法。由于许多人墨守成规，这样做并不是一件容易的事。一位机械设计师应该不断地探索改进现有的产品的方法，在此过程中应该认真选择原有的、经过验证的设计原理，将其与未经过验证的新观念结合起来。新设计本身会有许多缺陷和未能预料的问题发生，只有当这些缺陷和问题被解决之后，才能体现出新产品的优越性。因此，一个性能优越的产品诞

11、生的同时，也伴随着较高的风险。应该强调的是，如果设计本身不要求采用全新的方法，就没有必要仅仅为了变革的目的而采用新方法。 -本文译自 谷歌学术Mechanical DesignAbstract:A machine is a combination of mechanisms and other components which transforms, transmits. Examples are engines, turbines, vehicles, hoists, printing presses, washing machines, and movie cameras. Many of

12、 the principles and methods of design that apply to machines also apply to manufactured articles that are not true machines. The term mechanical design is used in a broader sense than machine design to include their design. the motion and structural aspects and the provisions for retention and enclo

13、sure 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 devices, such as switches, cams, valves, vessels, and mixers.Keywords: Mechanical Design mechanisms Design ProcessThe Desi

14、gn ProcessDesigning starts with a need real.Existing apparatus may need improvements in durability, efficiency, weight, speed, or cost. New apparatus may be needed to perform a function previouslydone by men, such as computation, assembly, or servicing. With the objective wholly or partlyIn the desi

15、gn preliminary stage, should allow to design the personnel fully to display the creativity, not each kind of restraint. Even if has had many impractical ideas, also can in the design early time, namely in front of the plan blueprint is corrected. Only then, only then does not send to stops up the in

16、novation the mentality. Usually, must propose several sets of design proposals, then perform the comparison. Has the possibility very much in the plan which finally designated, has used certain not in plan some ideas which accepts.When the general shape and a few dimensions of the several components

17、 become apparent, analysis can begin in earnest. The analysis will have as its objective satisfactory or superior performance, plus safety and durability with minimum weight, and a competitive cost. Optimum proportions and dimensions will be sought for each critically loaded section, together with a

18、 balance between the strengths of the several components. Materials and their treatment will be chosen. These important objectives can be attained only by analysis based upon the principles of mechanics, such as those of static for reaction forces and for the optimum utilization of friction; of dyna

19、mics for inertia, acceleration, and energy; of elasticity and strength of materials for stress and deflection; of physical behavior of materials; and of fluid mechanics for lubrication and hydrodynamic drives. The analyses may be made by the same engineer who conceived the arrangement of mechanisms,

20、 or, in a large company, they may be made by a separate analysis division or research group. Design is a reiterative and cooperative process, whether done formally or informally, and the analyst can contribute to phases other than his own. Product design requires much research and development. Many

21、Concepts of an idea must be studied, tried, and then either used or discarded. Although the content of each engineering problem is unique, the designers follow the similar process to solve the problems. Product liability suits designers and forced in material selection, using the best program. In th

22、e process of material, the most common problems for five (a) dont understand or not use about the latest application materials to the best information, (b) failed to foresee and consider the reasonable use material may (such as possible, designers should further forecast and consider due to improper

23、 use products. In recent years, many products liability in litigation, the use of products and hurt the plaintiff accused manufacturer, and won the decision), (c) of the materials used all or some of the data, data, especially when the uncertainty long-term performance data is so, (d) quality contro

24、l method is not suitable and unproven, (e) by some completely incompetent persons choose materials.Through to the above five questions analysis, may obtain these questions is does not have the sufficient reason existence the conclusion. May for avoid these questions to these questions research analy

25、ses the appearance indicating the direction. Although uses the best choice of material method not to be able to avoid having the product responsibility lawsuit, designs the personnel and the industry carries on the choice of material according to the suitable procedure, may greatly reduce the lawsui

26、t the quantity. May see from the above discussion, the choice material people should to the material nature, the characteristic and the processing method have comprehensive and the basic understanding. Finally, a design based upon function, and a prototype may be built. If its tests are satisfactory

27、, the initial design will undergo certain modifications that enable it to be manufactured in quantity at a lower cost. During subsequent years of manufacture and service, the design is likely to undergo changes as new ideas are conceived or as further analyses based upon tests and experience indicat

28、e alterations. Sales appeal.Some Rules for DesignIn this section it is suggested that, applied with a creative attitude, analyses can lead to important improvements and to the conception and perfection of alternate, perhaps more functional, economical,and durable products. To stimulate creative thou

29、ght, the following rules are suggested for the designer and analyst. The first six rules are particularly applicable for the analyst.1. A creative use of need of physical properties and control process.2. Recognize functional loads and their significance.3. Anticipate unintentional loads.4. Devise m

30、ore favorable loading conditions.5. Provide for favorable stress distribution and stiffness with minimum weight.6. Use basic equations to proportion and optimize dimensions.7. Choose materials for a combination of properties.8. Select carefully, stock and integral components.9. Modify a functional d

31、esign to fit the manufacturing process and reduce cost.10. Provide for accurate location and noninterference of parts in assembly. Machinery design covers the following contents.1. Provides an introduction to the design process , problem formulation ,safety factors.2. Reviews the material properties

32、 and static and dynamic loading analysis ,Including beam , vibration and impact loading. 3. Reviews the fundamentals of stress and defection analysis. 4. Introduces fatigue-failure theory with the emphasis on stress-life approaches to high-cycle fatigue design, which is commonly used in the design o

33、f rotation machinery. 5. Discusses thoroughly the phenomena of wear mechanisms, surface contact stresses ,and surface fatigue. 6. Investigates shaft design using the fatigue-analysis techniques. 7. Discusses fluid-film and rolling-element bearing theory and application 8. Gives a thorough introducti

34、on to the kinematics, design and stress analysis of spur gears , and a simple introduction to helical ,bevel ,and worm gearing. 9. Discusses spring design including compression ,extension and torsion springs. 10. Deals with screws and fasteners including power screw and preload fasteners. 11. Introd

35、uces the design and specification of disk and drum clutches and brakes.Machine DesignThe complete design of a machine is a complex process. The machine design is a creative work. Project engineer not only must have the creativity in the work, but also must in aspect and so on mechanical drawing, kin

36、ematics, engineerig material, materials mechanics and machine manufacture technology has the deep elementary knowledge. One of the first steps in the design of any product is to select the material from which each part is to be made. Numerous materials are available to todays designers. The function

37、 of the product, its appearance, the cost of the material, and the cost of fabrication are important in making a selection. A careful evaluation of the properties of a. material must be made prior to any calculations. Careful calculations are necessary to ensure the validity of a design. In case of

38、any part failures, it is desirable to know what was done in originally designing the defective components. The checking of calculations (and drawing dimensions) is of utmost importance. The misplacement of one decimal point can ruin an otherwise acceptable project. All aspects of design work should

39、be checked and rechecked. The computer is a tool helpful to mechanical designers to lighten tedious calculations, and provide extended analysis of available data. Interactive systems, based on computer capabilities, have made possible the concepts of computer aided design (CAD) and computer-aided ma

40、nufacturing (CAM). How does the psychologist frequently discuss causes the machine which the people adapts them to operate. Designs personnels basic responsibility is diligently causes the machine to adapt the people. This certainly is not an easy work, because certainly does not have to all people

41、to say in fact all is the most superior operating area and the operating process. Another important question, project engineer must be able to carry on the exchange and the consultation with other concerned personnel. In the initial stage, designs the personnel to have to carry on the exchange and t

42、he consultation on the preliminary design with the administrative personnel, and is approved. This generally is through the oral discussion, the schematic diagram and the writing material carries on. If front sues, the machine design goal is the production can meet the human need the product. The in

43、vention, the discovery and technical knowledge itself certainly not necessarily can bring the advantage to the humanity, only has when they are applied can produce on the product the benefit. Thus, should realize to carries on before the design in a specific product, must first determine whether the

44、 people do need this kind of productMust regard as the machine design is the machine design personnel carries on using creative ability the product design, the system analysis and a formulation product manufacture technology good opportunity. Grasps the project elementary knowledge to have to memori

45、ze some data and the formula is more important than. The merely service data and the formula is insufficient to the completely decision which makes in a good design needs. On the other hand, should be earnest precisely carries on all operations. For example, even if places wrong a decimal point posi

46、tion, also can cause the correct design to turn wrongly.A good design personnel should dare to propose the new idea, moreover is willing to undertake the certain risk, when the new method is not suitable, use original method. Therefore, designs the personnel to have to have to have the patience, bec

47、ause spends the time and the endeavor certainly cannot guarantee brings successfully. A brand-new design, the request screen abandons obsoletely many, knows very well the method for the people. Because many person of conservativeness, does this certainly is not an easy matter. A mechanical designer should unceasingly explore the improvement existing product the method, should earnestly choose originally, the process confirmation principle of design in this process, with has not unified it after the confirmation new idea.