This book has been written for mechanical engineering students who are beginning to study the theory of machines and mechanisms or professional English.Since the book was published in 2012, some universities take it as Chinese textbook of theory of machines and mechanisms for undergraduates, some universities take it as English textbook of theory of machines and mechanisms for undergraduates, some universities take it as bilingual education textbook of theory of machines and mechanisms, some universities take it as foreign students textbook of theory of machines and mechanisms,and some universities take it as international class students textbook of theory of machines and mechanisms. Such students will have acquired a set of mechanical engineering knowledge and the ability to use English language to express themselves in spoken and written forms.This edition has been influenced by changes in engineering education, suggestions by colleagues and users, and the author’s checkup.The major revisionary works for publishing this new edition are as follows.Effort has been made to remove all sorts of errors and misprints as far as possible.We adopt a simple mathematical manner for easy comprehension by students in Chapter 5, but there are not any examples to describe the new methods. So many examples have been added in Chapter 5.Geneva wheel with 6 slots will be more helpful to understand the action ratio, so we use a Geneva wheel with 6 slots instead of Geneva wheel with 4 slots.Some of examples have been added in Chapter 13 too.Twodimensional codes are added in this edition to describe the mechanisms animated figures.I acknowledge the efforts of professor He Cencheng of Beijing University of Technology for revisionary and compiled works for this edition.Zhao Jiaheng of Beijing Institute of Technology compiled some examples.Finally, I make an affectionate acknowledge to my PhD doctors team for their support.I am grateful to all readers who pointed out errors and mistakes of the previous edition and gave valuable suggestions.Zhang Chunlin本教材是为机械工程专业的学生学习机械原理课程或专业英语编写的。 本教材于2012年出版后，一些学校选其作为本科生机械原理课程的中文教材，教学时讲授中文，英语内容作为参考；一些学校选其作为机械原理课程的英文教材，教学时讲授英文，中文内容作为参考；一些开设双语教学的学校，选其作为本科生的英汉双语教学机械原理课程教材，教学时有时用英文讲授，有时用中文讲授，中、英文内容可用来对比和参考。一些学校选其作为外国留学生的机械原理课程教材，也有一些学校选其作为国际班的机械原理课程教材。本教材不但使学生获得机械原理的基本知识，还可以提高学生英语的口语和写作能力。 经过几年的使用，根据作者自查和用户意见反馈，对其进行了修改、补充和完善，如在平面连杆机构的综合内容中，引入了新方法，但缺少例题佐证。所以，本次修改增加了相应例题；在说明槽轮机构的运动特性时，采用了六槽槽轮代替四槽槽轮，这样就容易理解主动销轮和从动槽轮的转角关系，更容易理解槽轮机构的运动系数。在机械平衡设计一章中也增加了例题。 本次修订还更正了一些文字错误和语法错误，并引入了二维码技术，读者只要用手机扫描插图旁的二维码，就可以观看相应机构的动画，增强了本教材的可读性。 北京工业大学的何岑成老师参与了本次修订工作和英语教材的编审工作，北京理工大学的赵嘉珩为本教材增编了例题。 感谢我的博士生团队为本书的修订所做的工作。 由于编者水平有限，书中难免存在错误和疏漏之处，欢迎广大读者批评指正。 张春林Along with the rapid development of science and technology, the higher education will speed up internationalization. So it is necessary to compile a compatible textbook which not only has Chinese feature, but also makes for globalization. This is a new object that the teaching reform of Chinas higher education is faced with. On the one hand, the direct adoption of the foreign classical textbooks does not suit the actual state of our teaching in Chinese universities; on the other hand, the Chinese language textbooks cannot be brought in line with the international practice. Therefore, we will compile a bilingual textbook on “theory of machines and mechanisms” with the support of China Machine Press.This book is based on the basic teaching requirement of the “theory of machines and mechanisms” issued by the Ministry of Education. The basic concepts, basic principles and basic skills are reinforced, and we take the content of synthesis or design as a main clue to cultivate consciousness and capability of innovation for mechanical engineering. We hope that this book can include the features inheriting from the traditional textbooks, and can be in line with some foreign textbooks.1. Descriptions about “theory of machines and mechanisms” in the Chinese book1) This book is compiled with analysis of mechanisms, design of mechanisms, design of mechanism systems and dynamics of mechanisms.2) It highlights the analytical methods, such as kinematic analysis of mechanisms, force analysis of mechanisms, synthesis of mechanisms, cam mechanisms and balancing design, etc., and deemphasizes graphical methods.3) Some of the traditional contents of “theory of machines and mechanisms” are modified, integrated and expanded in this book.The concepts of mechanism and machine are defined in Chapter 1, and they are uptodate ideas. Composition principle of mechanisms is expanded to creative design of mechanisms. A new method which is used to determine the selflocking of a mechanism has been bring up, in which we will use the total reaction force acting on the friction cone or friction circle to determine selflocking phenomenon of a mechanism instead of use of efficiency. The concept is clear and the method is simple and practical. It highlights design as the main clue. By using the less complicated geometry algebra method instead of traditional coordinate transformation method in the analytical design of fourbar mechanism and cam mechanism, we can simplify mathematical design methods easily. This textbook also provides readers with creative design of mechanisms and design of mechanism systems to implement the overall content from simple to complicated; the contents of modified gears, helical gears, bevel gears, worm gears and intermittent mechanisms are simplified; the kinetostatic analysis of mechanism and force analysis including friction and selflocking are merged into a force analysis of mechanisms.4) This textbook attempts to be different from the traditional versions by adopting color rendered figures and threedimensional figures illustrations, which are clear and easy to read.5) The exercises are divided into four parts: reading, comprehension, practice, and selftest. Furthermore, there are some analog test papers. These problems can help students to understand the basic concepts and to prepare them to cope with real engineering problems in practice.Preface to the First EditionTheory of Machines and Mechanisms (Bilingual Edition)6) As a bilingual textbook, a lot of described contents are simplified to reduce its length. It shortens traditional Chinese text to keep concise and compact to highlight consistent context and accurate terminology.2. Descriptions about “theory of machines and mechanisms” in the English book1) The main purpose of the bilingual textbook is to help students study the contents of “theory of machines and mechanisms”, rather than only English.2) The English version is not the strict translation of the Chinese version, but their contents are coincident basically.3) All the figures, tables and formulas between the Chinese version and English version correspond with each other； they have a good comparability.4) The professional and conventional vocabularies are adopted from foreign textbooks; so the book has a good credibility.5) Basic English grammar of science and technology makes reading easy.6) The reading and comprehension which include the basic concepts are adopted from foreign textbooks.7) Some concepts between the Chinese version and English version are a little different, such as redundant degree of freedom and local degree of freedom, redundant constraint and virtual constraint. This will benefit students to some extent.The authors of the Chinese version are as follows.Professor Zhang Chunlin (Chapters 1, 2 and 3), Zhao Ziqiang (Chapters 4, 5 and 6), Li Zhixiang (Chapters 7 and 8), Ma Chao (Chapters 9, 10, 11, 12 and 13).Zhang Ying of Beijing University of Technology compiled and translated Chapters 1, 2, 3, 4, 5, 6, 7, 8, 9. Wang Zeyang compiled and translated Chapters 10 and 11. Feng Xinxin compiled and translated Chapters 12 and 13. Zhang Ying thoroughly compiled and edited the English Version and Professor Zhang Chunlin compiled and edited the entire bilingual text.AcknowledgmentsThe authors would like to express their thanks for the cooperation of all those individuals who generously made this item available.Sincere thanks also go to Professor Ge Wenjie of Northwestern Polytechnical University, who provided a part of 3D graphics. Some of the graphics are adopted from the other authors. We would like to express our thanks to them.Finally, we would like to make an affectionate acknowledgment to China Machine Press for the support and we acknowledge the efforts of editorial staff for bringing out the new bilingual version in an excellent format.It is hard to avoid errors and mistakes in the first edition, because the knowledge of English of authors is limited; the authors invite criticisms and suggestions from all readers for further improvement of the book, so that the errors can be corrected in future versions.Zhang ChunlinEver Bright Garden, Beijing随着科学技术的飞速发展和教育逐渐走向世界，编写具有中国特色、又逐步与发达国家接轨的教材，是中国高等学校教学改革所面临的新课题。直接引入国外教材的方法不适合国内的教学现状，单纯的中文教材不能满足逐步与国际接轨的需要。因此，在机械工业出版社的支持下，作者开始尝试编写中英文双语机械原理教材。 本教材的指导思想是在教育部颁布的教学基本要求基础上，加强基本理论、基本方法和基本技能的培养；以设计为主线，突出创新意识和创新设计能力的培养；既反映中国同类教材的内容与特色，又逐步与国外同类教材接轨。 1关于本教材中文部分的编写说明1)本教材按照机构分析、机构设计、机构系统设计和机构动力学设计的体系编写。 2)教材内容中淡化图解法、强化解析法，如机构运动分析、力分析、连杆机构综合、凸轮机构设计、平衡设计等，淡化了图解法，突出了解析法。 3）本教材对传统机械原理课程内容进行了修改、整合与拓展。在绪论中重新定义了机构与机器的基本概念,使其更具有时代特点；把机构组成原理拓展到机构创新设计；放弃传统的利用效率判断机构自锁的方法，改为利用总反力作用在摩擦锥或摩擦圆之内来判断机构的自锁现象，概念清晰，方法实用,把摩擦与自锁机构设计相结合，强化了设计主线;在连杆机构和凸轮机构的解析法设计中，放弃了传统的坐标变换法，采用了简单的几何代数法，简化了数学运算过程。 本教材还增加了创新设计、机构系统设计的内容，完善了从简单机构设计到复杂机构系统设计的整体内容；同时简化了齿轮机构中的变位齿轮、斜齿轮、锥齿轮、蜗杆机构以及其他常用机构的内容。把机构动态静力分析、摩擦与自锁、考虑摩擦的力分析等内容整合为机构的力分析。 4）为了突出教材的新颖性，学习了国外同类教材的插图风格，重新绘制了平面彩色渲染图和一些三维图形，代替了传统的黑白线条图形，层次分明，有益于对教材内容的理解。 5)改革了配套习题的体系与内容。本教材的配套习题集内容分为阅读、理解、设计和自测四个组成部分，习题集最后辅以部分模拟试卷，形成一套完整的课后训练系统。在加强基本理论、基本概念的基础上，采用与工程实践相结合的题目，突出了理论与实践相结合的训练目的，使学生逐步学习解决工程设计中的问题。 6）由于本书为双语教材，为了不增加篇幅，简化了传统中文教材的叙述内容，使论述更加简练。 2关于本教材英文部分的说明1)编写英汉双语教材，其目的是通过英文内容的学习，掌握机械原理的基本知识，为本专业领域内进行国际交流奠定基础。 2)英文内容没有采取严格的汉语翻译内容，而是强调基本内容的一致性和英文词义的准确性。 3)教材体系和内容与对应的中文教材相一致，如图、表、公式都有严格的对应，具有可比性。 4）编写中尽量采用国外同类教材中的常用标准专业词汇，具有可信性。 5）尽量采用常用的词汇和简单的初级科技语法，容易理解，具有可读性。 6）本书配套习题集中的阅读与理解部分，以基本概念与基本理论为主，参考大量原版教材及文献。 前言Theory of Machines and Mechanisms(Bilingual Edition)7）该书中，有些中英文的概念存在差别，有益于中外教材内容的接轨。如该书第2章中，中文教材中的局部自由度、虚约束，在英文教材中为多余自由度、多余约束。保留这些差别是有益的。 参加本书中文编写的教师有：张春林（第1章，第2章，第3章），赵自强（第4章，第5章，第6章），李志香（第7章，第8章），马超（第9章，第10章，第11章，第12章，第13章）。 参加英文编写的教师有：张颖（第1章，第2章，第3章，第4章，第5章，第6章，第7章，第8章，第9章），王泽洋（第10章，第11章）,冯欣欣（第12章，第13章）。 本书英文部分由北京工业大学的张颖负责统稿。全书由张春林负责统稿。另外，在编写过程中，西北工业大学的葛文杰教授提供了部分3D图形，还有一些老师提供了部分图形，编者表示感谢。 由于编者水平有限，书中难免存在错误和疏漏之处，特别是英文部分难免存在中国式的英文表述，敬请广大读者批评指正。 张春林于北京光大花园