机械原理英文

1、Theory of Machines and Mechanisms2022/8/26Todays TopicsWhat are we going to study in this course?Design ProcessCourse information and requirementsHow to be an engineer?Methods of learningA brief review of the machine historyIntroduction this course Homework2022/8/26Mechanism & MachineKinematicsKinet

2、ics or DynamicsKinematic analysisKinematic synthesisObjectsHow to analyze mechanism & How to synthesize mechanismWhat are Mechanism and Machine?2022/8/26The Content of our courseIt is broadly divided into two parts.1. Kinematics of Mechanism: the study of motion without regard to forces. That is abo

3、ut motion of the components and the basic geometry of the mechanism, and is not concerned with the forces which cause or affect the motion. All the components of the mechanism are, in general, considered rigid member.2. Kinetics or Dynamics of Mechanisms: the study of forces on the system in motion.

4、 2022/8/26The Content of our courseKinematics of Mechanisms is broadly divided into two branches: analysis and synthesisKinematic analysis is the analysis of the motion of a mechanism Kinematic synthesis is the development of a mechanism which will yield a desired set of motion characteristics.We wi

5、ll mainly deal with How to analyze mechanism & How to synthesize mechanism2022/8/26Methods of Learning1. More practice2. Have detail visits of our lab3. Pay attention to the machine you met4. More discussion2022/8/26Organization of the Course1. Class Instruction2. Homework & Quizzes3. Experiment4. S

6、imple Projects & Research paper5. Discussion & Communication2022/8/26InformationInstructor: 孟彩茹Class time :Monday，Friday 7:00-8:25pmClassroom: A06-306，A05-104Office: A02-206Tel.: 8578723E-mail: 2022/8/26Homework & QuizzesHomework will be assigned on every week except for week 1, and collected on the

7、 specified due date. Late homework will not be accepted. There will have several quizzes and all the quizzes and homework will be calculated in the final grade.2022/8/26Discussion SessionA discussion session will be held weekly, except for the first week, to discuss student questions and solve sampl

8、e problems.2022/8/26GradingHomework and quizzes - 15% Experiments - 5% Projects and discussion 15%Final Exam - 65% 2022/8/26The Textbook2022/8/26Reference Books1. 机械原理教程 申永胜 清华大学出版社 机械原理辅导与习题,申永胜,清华大学出版社 2. Mechanisms and Dynamics of Machinery, Hamilton H. Mabie, Charles F. Reinholtz3. Theory of Mac

9、hines and Mechanisms, J.E.Shigley, 4. Hong-sen Yan, Creative Design of Mechanical Device, 2022/8/26To be an engineerProfessional ethics, social and environmental responsibilities of engineers. Role of communication, considerations of risk, safety, and liability in engineering design and practice.202

10、2/8/26 ing a Good Designer One cannot learn design without “doing” designSimply “doing” design does not necessarily mean one is doing it wellThe best way is that do design and learn from the Design ProcessGood designers understand and create an overall experience, not simply an object2022/8/26“Why I

11、 Became Interested in DesignReal-world engineering involves much more than Engineering Science; creativity is interwoven with engineering physicsGreat designs come about with integration of Design Skills, creativity and Engineering Science spanning many disciplinesThis is especially true of todays p

12、roducts (e.g. HP printers involve ME, EE, CS, Materialsand business)Today we are less limited by technology than ever. We are increasingly limited by own creativity and ability to work together.2022/8/26Problem DefinitionDesign ObjectiveSpecificationDesign Constraints Conceptual DesignSelect Design

13、ConceptDesignAnalysis Prototype &TestEng. DrawingsMechanical design process2022/8/26Problem DefinitionStructural SynthesisDimensional SynthesisKinematic Analysis Static AnalysisStrength DesignKinetic AnalysisMechanism DesignMachine DesignMechanism and Machine Design Process2022/8/26A Brief Review of

14、 the Machine HistoryIt is a man-made object that transform the energy into another form. It could decrease the hard labor work and increase the working efficiency.It is a symbol of civilization.It is an important part of national economy.The modern civilization depends upon the mechanical engineerin

15、g. With the help of machines, our lives changes much better. The development of machine industry, push the step of the civilization forward. Introduction This Course1. The Concept of Machinery1.1General Information(1) MechanismA mechanism is a device, which produces specific mechanical motions. Thus

16、, the function of a mechanism is to transmit and modify a motion. We often use a drawing with some simple lines and symbols to describe the mechanism, and it is called kinematical diagram.(2) MachineA machine is a device which produces specific mechanical motions, and it can transmit or modify mecha

17、nical energy, materials and information. A machine may be a mechanism or a combination of mechanisms capable of transmitting or modifying motion and mechanical energy.(3) MachineryIn the viewpoint of kinematics, mechanism and machine have no difference，so mechanisms and machines are generally called

18、 machinery in mechanical engineering. There is no energy transforming and modifying in a mechanism, for example, mechanical watch is a mechanism but not a machine, because it can not transform energy.2022/8/26Example of the Machines and MechanismsMechanisms: pencil sharper, clock, folding chair, adj

19、ustable desk lamp, bikeMachines: robots, bulldozer, park rides, elevator, engine.Can you give an example?Some Mechanisms widely used in our life.Planar four-bar linkage, Cam, Gears, Ratchet mechanismWhat is machine and mechanism?Fig.1-1Internal combustion engine and scheme(内燃机及其机构简图)1piston(活塞)2coup

20、ler(连杆)3crank shaft(曲轴)4、5、6gear(齿轮)7cam(凸轮)8follower(推杆)9lever(杠杆)10valve(气门)11frame(缸体)2022/8/26A few problems to ask youWhat is a machine? What is a Mechanism? Please try to give an example and a definition!Is there any common characteristics of different machines? What are they?2022/8/26The Obje

21、ct to be investigatedMachineEnergy transformationFixed movement2022/8/26The Object to be investigatedMachine1. Composed of man-made elements2. The elements arranged to transmit motion3. Can transmit energy, and fulfill certain work for human being2022/8/26The Object to be investigatedMechanismA syst

22、em of elements arranged to transmit motion2022/8/26The Object to be investigatedMachinery The general concept of machines or mechanismsThe Parts of a machine1. Motors and Drivers2. Controller3. Working part4. transmission2022/8/26Is there any common characteristics of different machines?Same mechani

23、sm, different machines position of MachinesFig.1-2Composition of machine(机器组成示意图) A machine consists of prime power, transmission system and working system. A modern machine also contains a control system. Fig.1-2 shows the block diagram of composition of a machine.Fig.1-3Automatic gate (电动大门示意图)1dr

24、iver(驱动器)2gate (大门)3electromotor(电动机)4reducer(减速器)5chain driver(链传动)6rollers(滚轮) Fig.1-3b shows a diagram of an automatic gate. Fig.1-3a shows the composition of the driver. The prime power is electromotor 3 which has a high speed. But gate 2 needs a low speed to work, so we have to install gear mec

25、hanisms and chain mechanisms to modify the speed of electromotor 3. The reducer 4 and chain driver 5 are transmission system. Gate 2 consisting of the parallel linkages is called working system. Fig.1-4Constitute of the coupler(连杆的组成)1body of the coupler(连杆体)2bearing(小端轴承)3bearing bush(轴瓦)4head of t

26、he coupler(连杆头)5bolt(螺栓)6nut(螺母)7washer(垫圈)1.2Teaching Content and Object of the Course1. Research Object of the Course The research object of the course is the theory of machinery, and machinery contains mechanisms and machines. Therefore, the theory of mechanisms and machines is the important cont

27、ent of this course. The piston, coupler, crank, cam, gear and so on shown in Fig.1-1 are smallest motion units, and they are called links. The motion of links is an important content for us. 2. Content of This Course(1) Structural analysis of mechanismsIt involves the composition of mechanism, kinem

28、atical diagram, calculation of degree of freedom and analysis of mechanism.(2) Kinematics of mechanismsIt deals with the relative motions of links and forces acting on the links, thus it involves the velocity analysis, acceleration analysis, force analysis and synthesis of mechanism.(3) Dynamics of

29、machineryIt involves the inertia forces balancing and the fluctuation in speed and regulation.1. Purpose The machinery is closely related to human life, economic construction, and national defense construction, so mechanical industry can reflect a industry level of a country and a level of science a

30、nd technology. Although there are a lot of machines, the mechanisms consisting machines are finite. So on the basis of finite mechanisms to design some new machine is a creative work. It is also the purpose of this course. This course is the basis of some other subsequent courses, such as Machinery Design, Advanced Kinematics and Dynamics of Mechanisms, Mechanical Manufacture, etc. So the purpose of this course is also to lay the foundation for the further machine design.1.3 Purpose of This Course2. Conclusion1) Machinery is very important to develop the e