CONTENTS 2 Chapter 12 Balancing.....................570 12.0。lnti0 ductic0n4… 570 12.1 Static Balance… 571 12.2 Dynamic Balance....................................... 574 12.3 Balancing Linkages 579 Complete Force Balance of Linkages......... 580 12.4 Effect of Balancing on Shaking and Pin Forces................... 583 12.5 Effect of Balancing on Input Torque..5.85 12.6 Balancing the Shaking Moment in Linkages.............. 586 12.7 Measuring and correcting Imbalance. 590 12.8 Refere门CeS 591 12.9 Pr0 blems… 592 Chapter 13 Engine Dynamics......598 l3.0lntr0dUCi0n… 598 13.】ngine Design… 600 13.2 Slider-Crank Kinematics.......605 13.3 as Force and Gas Torque... 610 13.4 Equivalent Masses…6l4 13.5 Inertia and Shaking Forces 617 13.6 Inertia and Shaking Torques......620 13.7 Total Engine Torque… 622 13.8 Flywhee......822 13.9 Pin Forces in the single-Cylinder Engine............................ 623 13.10 Balancing the Single-Cylinder Engine........................................ 631 13.11 Design Trade-offs and Ratios................ 634 Controd/Crank Ratio.… 634 Bore/stroke Ratio634 .............................. 635 13.12 13.13 Pr○olems44.635 13.14 P jects… 638 chapter 14 Multicylinder Engines........639 14.0 lntr0 duction… 39 14.1 Multicylinder Engine Designs............... 641 14.2 The Crank Phase Diagram........... 644 14.3 Shaking Forces in Inline Engines. 646 14.4 Inertia Torque in Inline Engines. 649 14.5 Shaking Moment in Inline Engines....................... 650 14.6 Even Firing.................. 652 Two-Stroke Cycle Engine........................653 Fourstroke Cycle Engine.655 14.7 vee Engine configurations661 14.8 Opposed Engine Configurations.64 14.9 Balancing Multicylinder Engines..... 675 Secondary Balance in the Four-Cylinder Inline Engine .......................679 14.10 References…682 14.11 Bibliography… 682 14.12 Problems.…682 14.13 Projects683
V DESIGN OF MACHINERY CONTENTS Chapter 15 Com Dynamics ,685 15.0 Introduction ... .685 15.1 Dynamic Force Analysis of the Force-Closed Cam Follower ........... 686 Undamped Response,..686 Damped Response........ 689 15.2 4444444i4i44444444 15.3 Kinetostatic Force Analysis of the Force-Closed Cam-Follower .698 15.4 Kinetostatic Force Analysis of the Form-Closed Cam-Follower. .702 15.5 Camshaft Torque.… .706 15.6 Measuring Dynamic Forces and Accelerations 709 15.7 Practical Considerations..............13 15.8 References..... 713 15.9 Bibliography 713 15.10 Problems... Z14 Chapter 16 Engineering Design..... 717 16.0 Introduction 7.17 16.1 A Design Case Study 718 16.2 0Se.2222222 723 16.3 References 723 Appendix A Computer Programs 725 AO Introduction .725 Al General Information .227 A2 General Program Operation 727 A3 Program FOURBAR...... 735 A4 Program FIVBAR. 743 A5 Program SIXBAR A.A... 745 A6 Program SLIDER. 749 A7 Program DVNACAM 751 A8 Program ENGINE. 757 A9 Program MATRIX........ 764 Appendix B Material Properties... 765 Appendix C Geometric Properties.................... 769 Appendix D Spring Data .............. .771 Appendix E Atlas of Geared Fivebar Linkage Coupler Curves.....775 Appendix F Answers to Selected Problems.... 781 Index..... 795 CD-ROM Index 809
Chapter 15 Com Dynamics ................................................................ 685 15.0 Introduction ................................................................................................. 685 15.1 Dynamic Force Analysis of the Force-Closed Cam Follower .............686 Undamped Response, ............................................................................ 686 Damped Response ................................................................................. 689 15.2 Resonance ................................................................................................... 696 15.3 Kinetostatic Force Analysis of the Force-Closed Cam-Follower ........ 698 15.4 Kinetostatic Force Analysis of the Form-Closed Cam-Follower. ......... 702 15.5 Camshaft Torque ........................................................................................ 706 15.6 Measuring Dynamic Forces and Accelerations ....................................709 15.7 Practical Considerations ...........................................................................713 15.8 References ................................................................................................... 713 15.9 Bibliography ................................................................................................. 713 15.10 Problems ....................................................................................................... 714 Chapter 16 Engineering Design.......................................................... 717 16.0 Introduction ................................................................................................. 717 16.1 A Design Case Study .................................................................................. 718 16.2 Closure .......................................................................................................... 723 16.3 References ................................................................................................... 723 Appendix A Computer Programs....................................................... 725 AO Introduction ................................................................................................. 725 A1 General Information .................................................................................. 727 A2 General Program Operation ....................................................................727 A3 Program FOURBAR......................................................................................... 735 A4 Program FIVEBAR........................................................................................... 743 A5 Program SIXBAR............................................................................................ 745 A6 Program SLIDER............................................................................................. 749 A7 Program DVNACAM...................................................................................... 751 A8 Program ENGINE........................................................................................... 757 A9 Program MATRIX............,............................................................................... 764 Appendix B Material Properties.......................................................... 765 Appendix C Geometric Properties .................................................... 769 Appendix D Spring Data ...................................................................... 771 Appendix E Atlas of Geared Fivebar Linkage Coupler Curves .....775 Appendix F Answers to Selected Problems...................................... 781 Index .........................................,................................................................ 795 CD-ROM Index .......................................................................................... 809
PREFACE to the Second Edition Why is it we never have time to do it right the first time,but always seem to have time to do it over? ANONYMOUS The second edition has been revised based on feedback from a large number of users of the book.In general,the material in many chapters has been updated to reflect the latest research findings in the literature.Over 250 problem sets have been added,more than doubling the total number of problems.Some design projects have been added also.All the illustrations have been redrawn,enhanced,and improved. Coverage of the design process in Chapter I has been expanded.The discussions of the Grashof condition and rotatability criteria in Chapter 2 have been strengthened and that of electric motors expanded.A section on the optimum design of approximate straight line link- ages has been added to Chapter 3.A discussion of circuits and branches in linkages and a section on the Newton-Raphson method of solution have been added to Chapter 4.A discus- sion of other methods for analytical and computational solutions to the position synthesis problem has been added to Chapter 5.This reflects the latest publications on this subject and is accompanied by an extensive bibliography. The chapters formerly devoted to explanations of the accompanying software (old Chap- ters 8 and 16)have been eliminated.Instead,a new Appendix A has been added to describe the programs FOURBAREIVEBARSrXBARSLIDERDYNACAMENGINEand MATRIXthat are on the attached CD-ROM.These programs have been completely rewritten as Windows ap- plications and are much improved.A student version of the simulation program Working Model by Knowledge Revolution,compatible with both Macintosh and Windows computers, is also included on CD-ROM along with 20 models of mechanisms from the book done in that package.A user's manual for Working Model is also on the CD-ROM. Chapter 8 on cam design(formerly 9)has been shortened without reducing the scope of its coverage.Chapter 9 on gear trains(formerly 10)has been significantly expanded and enhanced, especially in respect to the design of compound and epicyclic trains and their efficiency.Chapter 10on dynamics fundamentals has been augmented with material formerly in Chapter 17to give a more coherent treatment of dynamic modeling.Chapter 12 on balancing (formerly 13)has been expanded to include discussion of moment balancing of linkages. The author would like to express his appreciation to all the users and reviewers who have made suggestions for improvement and pointed out errors,especially those who responded to the survey about the first edition.There are too many to list here,so rather than risk offense by omit- ting anyone,let me simply extend my sincerest thanks to you all for your efforts. '.1(p6erd.J.(prton :Mattapoisett,:Mass. 5tugustr 1997
PREFACE to the Second Edition Why is it we never have time to do it right the first time, but always seem to have time to do it over? ANONYMOUS The second edition has been revised based on feedback from a large number of users of the book. In general, the material in many chapters has been updated to reflect the latest research findings in the literature. Over 250 problem sets have been added, more than doubling the total number of problems. Some design projects have been added also. All the illustrations have been redrawn, enhanced, and improved. Coverage of the design process in Chapter 1 has been expanded. The discussions of the Grashof condition and rotatability criteria in Chapter 2 have been strengthened and that of electric motors expanded. A section on the optimum design of approximate straight line linkages has been added to Chapter 3. A discussion of circuits and branches in linkages and a section on the Newton-Raphson method of solution have been added to Chapter 4. A discussion of other methods for analytical and computational solutions to the position synthesis problem has been added to Chapter 5. This reflects the latest publications on this subject and is accompanied by an extensive bibliography. The chapters formerly devoted to explanations of the accompanying software (old Chapters 8 and 16) have been eliminated. Instead, a new Appendix A has been added to describe the programs FOURBAR,FIVEBAR,SrXBAR,SLIDER,DYNACAM,ENGINE,and MATRIXthat are on the attached CD-ROM. These programs have been completely rewritten as Windows applications and are much improved. A student version of the simulation program Working Model by Knowledge Revolution, compatible with both Macintosh and Windows computers, is also included on CD-ROM along with 20 models of mechanisms from the book done in that package. A user's manual for Working Model is also on the CD-ROM. Chapter 8 on cam design (formerly 9) has been shortened without reducing the scope of its coverage. Chapter 9 on gear trains (formerly 10) has been significantly expanded and enhanced, especially in respect to the design of compound and epicyclic trains and their efficiency. Chapter 10on dynamics fundamentals has been augmented with material formerly in Chapter 17to give a more coherent treatment of dynamic modeling. Chapter 12 on balancing (formerly 13) has been expanded to include discussion of moment balancing of linkages. The author would like to express his appreciation to all the users and reviewers who have made suggestions for improvement and pointed out errors, especially those who responded to the survey about the first edition. There are too many to list here, so rather than risk offense by omitting anyone, let me simply extend my sincerest thanks to you all for your efforts. '.1{p6ertL. 'J,{prton :Mattapoisettl :Mass. 5tugustl 1997
PREFACE to the First Edition When I hear,Iforget When I see,I remember When I do,I understand ANCIENT CHINESE PROVERB This text is intended for the kinematics and dynamics of machinery topics which are of- ten given as a single course,or two-course sequence,in the junior year of most mechan- ical engineering programs.The usual prerequisites are first courses in statics,dynamics and calculus.Usually,the first semester,or portion,is devoted to kinematics,and the sec- ond to dynamics of machinery.These courses are ideal vehicles for introducing the me- chanical engineering student to the process of design,since mechanisms tend to be intu- itive for the typical mechanical engineering student to visualize and create.While this text attempts to be thorough and complete on the topics of analysis,it also emphasizes the synthesis and design aspects of the subject to a greater degree than most texts in print on these subjects.Also,it emphasizes the use of computer-aided engineering as an ap- proach to the design and analysis of this class of problems by providing software that can enhance student understanding.While the mathematical level of this text is aimed at sec- ond-or third-year university students,it is presented de novo and should be understand- able to the technical school student as well. Part I of this text is suitable for a one-semester or one-term course in kinematics. Part II is suitable for a one-semester or one-term course in dynamics of machinery.Alter- natively,both topic areas can be covered in one semester with less emphasis on some of the topics covered in the text. The writing and style of presentation in the text is designed to be clear,informal,and easy to read.Many example problems and solution techniques are presented and spelled out in detail,both verbally and graphically.All the illustrations are done with computer- drawing or drafting programs.Some scanned photographic images are also included. The entire text,including equations and artwork,is printed directly from computer disk by laser typesetting for maximum clarity and quality.Many suggested readings are pro- vided in the bibliography.Short problems,and where appropriate,many longer,unstruc- tured design project assignments are provided at the ends of chapters.These projects provide an opportunity for the students to do and understand. The author's approach to these courses and this text is based on over 35 years' experience in mechanical engineering design,both in industry and as a consultant. He has taught these subjects since 1967,both in evening school to practicing engi- neers and in day school to younger students.His approach to the course has evolved
PREFACE to the First Edition When I hear, Iforget When I see, I remember When I do, I understand ANCIENT CHINESE PROVERB This text is intended for the kinematics and dynamics of machinery topics which are often given as a single course, or two-course sequence, in the junior year of most mechanical engineering programs. The usual prerequisites are first courses in statics, dynamics and calculus. Usually, the first semester, or portion, is devoted to kinematics, and the second to dynamics of machinery. These courses are ideal vehicles for introducing the mechanical engineering student to the process of design, since mechanisms tend to be intuitive for the typical mechanical engineering student to visualize and create. While this text attempts to be thorough and complete on the topics of analysis, it also emphasizes the synthesis and design aspects of the subject to a greater degree than most texts in print on these subjects. Also, it emphasizes the use of computer-aided engineering as an approach to the design and analysis of this class of problems by providing software that can enhance student understanding. While the mathematical level of this text is aimed at second- or third-year university students, it is presented de novo and should be understandable to the technical school student as well. Part I of this text is suitable for a one-semester or one-term course in kinematics. Part II is suitable for a one-semester or one-term course in dynamics of machinery. Alternatively, both topic areas can be covered in one semester with less emphasis on some of the topics covered in the text. The writing and style of presentation in the text is designed to be clear, informal, and easy to read. Many example problems and solution techniques are presented and spelled out in detail, both verbally and graphically. All the illustrations are done with computerdrawing or drafting programs. Some scanned photographic images are also included. The entire text, including equations and artwork, is printed directly from computer disk by laser typesetting for maximum clarity and quality. Many suggested readings are provided in the bibliography. Short problems, and where appropriate, many longer, unstructured design project assignments are provided at the ends of chapters. These projects provide an opportunity for the students to do and understand. The author's approach to these courses and this text is based on over 35 years' experience in mechanical engineering design, both in industry and as a consultant. He has taught these subjects since 1967, both in evening school to practicing engineers and in day school to younger students. His approach to the course has evolved
XX DESIGN OF MACHINERY PREFACE a great deal in that time,from a traditional approach,emphasizing graphical analysis of many structured problems,through emphasis on algebraic methods as computers be- came available,through requiring students to write their own computer programs,to the current state described above. The one constant throughout has been the attempt to convey the art of the design pro- cess to the students in order to prepare them to cope with real engineering problems in practice.Thus,the author has always promoted design within these courses.Only re- cently,however,has technology provided a means to more effectively accomplish this goal,in the form of the graphics microcomputer.This text attempts to be an improve- ment over those currently available by providing up-to-date methods and techniques for analysis and synthesis which take full advantage of the graphics microcomputer,and by emphasizing design as well as analysis.The text also provides a more complete,mod- em,and thorough treatment of cam design than existing texts in print on the subject. The author has written several interactive,student-friendly computer programs for the design and analysis of mechanisms and machines.These programs are designed to enhance the student's understanding of the basic concepts in these courses while simul- taneously allowing more comprehensive and realistic problem and project assignments to be done in the limited time available.than could ever be done with manual solution techniques,whether graphical or algebraic.Unstructured,realistic design problems which have many valid solutions are assigned.Synthesis and analysis are equally emphasized. The analysis methods presented are up to date,using vector equations and matrix tech- niques wherever applicable.Manual graphical analysis methods are de-emphasized.The graphics output from the computer programs allows the student to see the results of vari- ation of parameters rapidly and accurately and reinforces learning. These computer programs are distributed,on CD-ROM,with this book which also contains instructions for their use on any IBM compatible,Windows 3.1 or Windows 95/ NT capable computer.The earlier DOS versions of these programs are also included for those without access to Windows.Programs SLIDERFOURBARFIVEBARand SIXBARan- alyze the kinematics of those types of linkages.Program FOURBARalso does a complete dynamic analysis of the fourbar linkage in addition to its kinematics.Program DYNACAM allows the design and dynamic analysis of cam-follower systems.Program ENGINEan- alyzes the slider-crank linkage as used in the internal combustion engine and provides a complete dynamic analysis of single and multicylinder engine configurations,allowing the mechanical dynamic design of engines to be done.Program MATRIXis a general pur- pose linear equation system solver.All these programs,except MATRIX.provide dynam- ic,graphical animation of the designed devices.The reader is strongly urged to make use of these programs in order to investigate the results of variation of parameters in these ki- nematic devices.The programs are designed to enhance and augment the text rather than be a substitute for it.The converse is also true.Many solutions to the book's examples and to the problem sets are provided on the CD-ROM as files to be read into these pro- grams.Many of these solutions can be animated on the computer screen for a better dem- onstration of the concept than is possible on the printed page.The instructor and students are both encouraged to take advantage of the computer programs provided.Instructions for their use are in Appendix A. The author's intention is that synthesis topics be introduced first to allow the students to work on some simple design tasks early in the term while still mastering
a great deal in that time, from a traditional approach, emphasizing graphical analysis of many structured problems, through emphasis on algebraic methods as computers became available, through requiring students to write their own computer programs, to the current state described above. The one constant throughout has been the attempt to convey the art of the design process to the students in order to prepare them to cope with real engineering problems in practice. Thus, the author has always promoted design within these courses. Only recently, however, has technology provided a means to more effectively accomplish this goal, in the form of the graphics microcomputer. This text attempts to be an improvement over those currently available by providing up-to-date methods and techniques for analysis and synthesis which take full advantage of the graphics microcomputer, and by emphasizing design as well as analysis. The text also provides a more complete, modem, and thorough treatment of cam design than existing texts in print on the subject. The author has written several interactive, student-friendly computer programs for the design and analysis of mechanisms and machines. These programs are designed to enhance the student's understanding of the basic concepts in these courses while simultaneously allowing more comprehensive and realistic problem and project assignments to be done in the limited time available, than could ever be done with manual solution techniques, whether graphical or algebraic. Unstructured, realistic design problems which have many valid solutions are assigned. Synthesis and analysis are equally emphasized. The analysis methods presented are up to date, using vector equations and matrix techniques wherever applicable. Manual graphical analysis methods are de-emphasized. The graphics output from the computer programs allows the student to see the results of variation of parameters rapidly and accurately and reinforces learning. These computer programs are distributed, on CD-ROM, with this book which also contains instructions for their use on any IBM compatible, Windows 3.1 or Windows 95/ NT capable computer. The earlier DOS versions of these programs are also included for those without access to Windows. Programs SLIDER,FOURBAR,FIVEBARand SIXBARanalyze the kinematics of those types of linkages. Program FOURBARalso does a complete dynamic analysis of the fourbar linkage in addition to its kinematics. Program DYNACAM allows the design and dynamic analysis of cam-follower systems. Program ENGINEanalyzes the slider-crank linkage as used in the internal combustion engine and provides a complete dynamic analysis of single and multicylinder engine configurations, allowing the mechanical dynamic design of engines to be done. Program MATRIXis a general purpose linear equation system solver. All these programs, except MATRIX,provide dynamic, graphical animation of the designed devices. The reader is strongly urged to make use of these programs in order to investigate the results of variation of parameters in these kinematic devices. The programs are designed to enhance and augment the text rather than be a substitute for it. The converse is also true. Many solutions to the book's examples and to the problem sets are provided on the CD-ROM as files to be read into these programs. Many of these solutions can be animated on the computer screen for a better demonstration of the concept than is possible on the printed page. The instructor and students are both encouraged to take advantage of the computer programs provided. Instructions for their use are in Appendix A. The author's intention is that synthesis topics be introduced first to allow the students to work on some simple design tasks early in the term while still mastering