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Machine Design Fundamentals (II) 机械设计基础（2） Problem–solving strategy 解决问题的策略 No textbook can adequately cover the many individual situations of machine design.Designers must be knowledgeable about the basic principles and then develop their own methods and design philosophies to solve a specific problem. 没有一本教科书能覆盖全部机械设计的问题。因此设计师必须熟悉基本设计原理，针对具体的问题找到自己的解决方法和设计理念。 Four-step approach 四步骤法 There is, however, a practical approach to problem solving that has been found to be the most useful and quite flexible. Its simplest form involves four steps: 然而，有一种最有效又灵活的实用方法能帮助你解决问题，他分以下四个简单的步骤: 1.statement of problem 问题描述 What is it all about? Is it a real problem? Is there a real need for a solution? A problem well stated is half solved. 问题是什么？它实际存在吗？有必要找出解决方法吗？对问题尽力描述等于已经解决了一半。 2. Analysis. 分析 What is the cause of the problem? Improper development? A human error? A technical error? A need for greater performance? 问题的起因是什么？设计问题？人为错误？技术错误？需要更好的性能？ 3. Illumination (inspiration, imagination) 灵感 What solution are possible? What are the options ? 有何解决方案？如何选择？ 4. Decision 决策 Which solution is preferable? Which option has the most to offer? 那个解决方案更好？那个选项解决问题最多？ Certain design problems require some hard thinking, in which case it becomes necessary to outline in writing the anSWers to each of the four steps. 有些特定的问题需要进行努力的思考，在此情况下，有必要针对上述每个问题写下答案。 机械设计图 Value engineering 价值工程法 The system of value engineering is designed to lower manufacturing costs without affecting product function, quality or reliability. In a typical value engineering program a product is resolved to its smallest components to determine if cost –saving changes can be made in design, materials, and manufacturing. Value engineering is especially suitable for fastening and assembly because about 50% of all manufacturing costs are due to these two factors. 所谓价值工程法，就是在不影响产品功能、质量和稳定性的基础上，通过设计降低制造成本。在一个典型的价值工程法项目中，会使用最少的零件来设计产品，并确定是否可以通过设计、材料以及制造方法来降低成本。价值成本法特别适用于紧固和装配，因为它们两项约占整个制造成本的50%。 Checklist 检查表 A More direct approach to design consists of checking each component by asking the following questions。 这是一种更直接的方法，设计一个包括每个零件的检查表格，并询问以下问题： 1.How does it function within the system? Under what conditions must it function? 它在系统中如何运作？在什么情况下必须启动？ 2.How well do we know loads, speeds , and material properties? 其负载，速度和材料特性如何？ 3.What is the mode of failure? How safe is the part against failure? 失效模式如何？部件如何防止失效？ 4.How can the part best be manufactured, maintained and replaced? 该部件应如何制造？保养或更换来保持其最好的功能？ 5.Should the part be purchased? 该部件是否应该外购？ Troubleshooting 故障排除 故障排除表 In machine design, as in any other human endeavor, things rarely go as planned.The “bugs” are not always where one expected them to come. If the machine is still on the test stand, corrections can often be made with relative ease and at reasonable cost. However, once it has reached the customer, the price of making corrections has increased greatly (perhaps ten fold). 如同其他人力活动一样，机械设计过程往往会和计划有出入。设计“漏洞”往往不期而至。如果机械仍在试验阶段，则改正错误相对比较容易，成本也低。但是如果机器已经送到用户手中，则改正的成本会大大上升（可能高达10倍）。 The remedial action is then referred to as mechanical troubleshooting: an exercise in symptom diagnosis. Since its purpose is to identify and eliminate malfunctions, it can be an invaluable source of products improvements. 补救措施就称之为故障排除：即根据症状对机器进行诊断。这是一个找出问题并排除故障的过程，因此对于产品改善大有帮助。 The imperfection of new designs may be due partly to human negligence and ignorance, but they are primarily due to enormous complexity of modern machines. The interacting factors are so numerous that the probability of covering all potential failures is small. Troubleshooting is therefore inevitable. 新产品设计的不完美部分是因为人文的疏忽和错误，但更大程度上是现代机器的复杂性所导致。相互影响的因素是如此之多，以至于要全部考虑覆盖到几无可能。因此故障排除是必要的手段。 同译翻译--专业翻译服务提供商，您身边的翻译专家。 更多翻译服务和产品信息，敬请关注同译翻译服务号。 | 
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