机械原理 英汉双语 教学课件 作者 张春林 Chapter 6 Design of Cam Mechanisms.pptx

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1、Chapter6DesignofCamMechanisms1.CompositionandCharacteristicsofCamMechanisms6.1IntroductionFig.6-1　Cammechanisms(盘形凸轮机构)Acammechanismconsistsofcam,followerandframe,anditbelongstothecategoryofhigherpairmechanism.Fig6-1showstwokindsofcammechanisms，inwhichFig6-1ashowsadiskcamwithatranslatingfollower,and

2、Fig6-1bshowsadiskcamwithanoscillatingfollower.Cammechanismiswidelyusedinautomaticmachines,internalcombustionengines,machinetools,printingmachines,andsoon.Comparedtolinkages,camsareeasierdesignedtogiveaspecificoutputmotion.Camsalsohaveasimplestructureandreliableperformance.2.TypesofCamMechanisms(1)

3、Typesofcams(2)Typesoffollowershapes（Fig6-4）(3)Typesoffollowermotion（Fig6-4、Fig6-5）(4)TypesofmotionconstraintsDisccam（Fig6-1）Translatingcam（Fig6-2）Spatialcam（Fig6-3）KnifeedgefollowerRollerfollowerFlatfacedfollowerSphericalfacedfollowerReciprocatingfollowerOscillatingfollowerForceclosure（Fig6-6）Form

4、closure（Fig6-7）Fig.6-2　Translatingcammechanisms(移动凸轮机构)Fig.6-3　Spatialcammechanisms(空间凸轮机构)Fig.6-4　Followertypes(从动件的分类)Fig.6-5　Disccamwithradialfollower(直动从动件盘形凸轮机构)Fig.6-6　Force-closedcammechanism(力封闭凸轮机构)Fig.6-7　Form-closedcammechanism(形封闭式凸轮机构)3.CamsTerminology1)Camprofile2)Basiccircle3)Tracepoi

5、nt4)Pitchcurveofthecam5)Primecircle6)Pressureangle7)Risetravel8)Returntravel9)Stroke10)Angleofascent11)Angleofdescent12)Angledweltatthehighestposition13)Angledweltatthelowestposition14)Camangle15)FollowerdisplacementFig.6-8　Nomenclaturesofcammechanism(凸轮机构名词术语)1—follower(从动件)2—pressureangle(压力角)3—tr

6、acepoint(轨迹点)4—pitchcurve(理论廓线)5—camprofile(凸轮实际廓线)6—primecircle(理论廓线基圆)7—basecircle(实际廓线基圆)Fig.6-9　Camangleandfollowerdisplacement(凸轮转角与从动件的位移)Fig.6-10　Motionofthefollower(凸轮机构运动循环图)1.BasicTypesofFollowerMotions(1)Polynomialmotions6.2BasicTypesofFollowerMotionandDesign1)ConstantvelocitymotionFig.6-

7、11　Constant-velocitycurve(等速运动规律)2)ConstantaccelerationanddecelerationmotionFig.6-12　Constantaccelerationanddecelerationcurve(等加速等减速运动规律)3）The3-4-5polynomialmotionFig.6-13　3-4-5polynomialcurve(五次多项式运动