【正文】 rs until the l 960s and the 1 970s had， by the l990s， slipped back and lost their leadership． On the contrary, our Country is rapidly picking up her position in manufacturing industry since the l 9 80s and is playing a more and more vital role in the global market． To accelerate such an industrializing process of our country, highly skilled design engineers having extensive knowledge and expertise are needed． That is why the course of machinery design is of great significance for students of engineering． The course of machinery design is considerable different from those background subjects in science and mathematics． For many students， it is perhaps one of their basic professional engineering courses concerned with obtaining solutions to practical problem s． Definitely these solutions must clearly represent an understanding of the underlying science， usually such an understanding may not be sufficient， empirical knowledge or engineering judgement has to be also involved． Furthermore， due to be professional nature of this subject， most design problems may not have one right solution． Nevertheless it is achievable to determine a better design from all feasible solutions． 1． 2 Machinery and ponents A stateoftheart machine may enpass all or part of mechanical， electrical， control， sensor， monitoring and lubricating sub—systems． In terms of the functions of those parts， the machine can also be viewed to be prised of power， transmission， execution and control／ manipulation parts． Regardless of the plexity, however， the major functional part may be still the mechanical system． For convenience of analysis， the mechanical system can be deposed int0． mechanisms that are designed to execute some specific tasks． And the mechanism can be further deposed into mechanical ponents． In this sense， the mechanical ponents are the fundamental elements of machinery． On the whole， mechanical ponents can be classified as universal and special ponents． Bolts， gear and chains are the typical examples of the universal ponents which can be used extensively in different machines across various industrial sectors． Turbine blades， crankshaft and aircraft propeller are the examples of the special ponents， which Can be used extensively in different machines across various industrial sectors． turbine blades， crankshaft and aircraft propeller are the examples of the special ponents， which are designed for some specific purposes． In addition to this， if a number of ponents are manufactured， assembled and even equipped as an individual system， e． g． leaf spring set in a vehicle， it is also termed as a mechanical part． 中英文資料 3 A good machine definitely requires quality individual ponents． Thus， the design of ponents is very important． When designing a machine， on the other hand， engineers invariably find that requirements and constraints of its ponents are interrelated． As a local portion， the ponent is expected to play a certain role on the machine and therefore must be appropriately restrained by the whole system． The design of a gear drive in a speed—reducer， for instance， depends upon not only the strength and stiffness， but also the space available for the gears in the shaft and relation with other transmission drive． This means that the design of the mechanical ponents inevitably requires a whole view in the whole system． Due to relationship between a machine and its ponents， the process of machinery design usually covers interconnected designs of machine， parts， and ponents． Any modification and adjustment in one ponent may considerably affect the designs of other ponents or parts． To present the best possible design solution， the iteration of evaluation， analysis and optimization across all the process seem indispensable． 1． 3 Overview of machinery design This course is primarily concerned with the design of specific ponents of machines or mechanical systems． Competence in this area is basic to the consideration and synthesis of plete machines and systems in subsequent courses and professional practice． It Can be seen that even the design of a single bolt or spring needs the designer’s thorough understanding of the principles and methods of machinery design together with empirical information， good judgment and even a degre3e of ingenuity in order t