平面四桿機(jī)構(gòu)的演化Evolutionofplanarfourbarmechanisms主講人：周會(huì)娜基本型式一一鉸鏈四桿機(jī)構(gòu)Basictype-hingefourbarmechanism目錄CONTENTS1234曲柄滑塊機(jī)構(gòu)IntroductiontoMechanicalDrawing偏心輪機(jī)構(gòu)Drawingformatofmechanicaldrawings導(dǎo)桿機(jī)構(gòu)FrameofMechanicalDrawing定塊機(jī)構(gòu)Writingfontsformechanicaldrawings5搖塊機(jī)構(gòu)Thesignificanceoflearningmechanicaldrawing1曲柄滑塊機(jī)構(gòu)CrankslidermechanismONE曲柄搖桿機(jī)構(gòu)crank-rockermechanism一、曲柄滑塊機(jī)構(gòu)Crankslidermechanism當(dāng)AB桿能整周回轉(zhuǎn)成為曲柄時(shí)，該機(jī)構(gòu)稱為曲柄滑塊機(jī)構(gòu);否則該機(jī)構(gòu)稱為擺桿滑塊機(jī)構(gòu)。WhentheABrodcanrotateallthewaytobecomeacrank,thismechanismiscalledacrankslidermechanism;Otherwise,themechanismiscalledapendulumslidermechanism.曲柄搖桿機(jī)構(gòu)Crankrockermechanism一、曲柄滑塊機(jī)構(gòu)Crankslidermechanism對(duì)心曲柄滑塊機(jī)構(gòu)centricslider-crankmechanism偏置曲柄滑塊機(jī)構(gòu)offsetslider-crankmechanism一、曲柄滑塊機(jī)構(gòu)Crankslidermechanism對(duì)心曲柄滑塊機(jī)構(gòu):曲柄回轉(zhuǎn)中心與滑塊移動(dòng)導(dǎo)路中心線無(wú)偏距。Centeredcrankslidermechanism:Thereisnooffsetbetweenthecrankrotationcenterandthecenterlineoftheslidermovementguide.一、曲柄滑塊機(jī)構(gòu)Crankslidermechanism偏置曲柄滑塊機(jī)構(gòu):曲柄回轉(zhuǎn)中心至滑塊移動(dòng)導(dǎo)路中心線存在垂直距離e(即有偏距)Biascrankslidermechanism:Thereisaverticaldistancee(i.e.offset)betweenthecrankrotationcenterandthecenterlineoftheslidermovementpath一、曲柄滑塊機(jī)構(gòu)Crankslidermechanism偏置曲柄滑塊機(jī)構(gòu)offsetslider-crankmechanism偏心的距離e稱作偏心距。Thedistanceeofeccentricityiscalledeccentricity.滑塊的兩個(gè)極限位置之間的距離稱為機(jī)構(gòu)的行程H。ThedistancebetweenthetwolimitpositionsoftheslideriscalledthetravelHofthemechanism.一、曲柄滑塊機(jī)構(gòu)Crankslidermechanism曲柄滑塊機(jī)構(gòu)的運(yùn)動(dòng)特性Kinematiccharacteristicsofcrankslidermechanism1.急回運(yùn)動(dòng)和行程速比系數(shù)1.Quickreturnmotionandtravelspeedratiocoefficient偏置曲柄滑塊機(jī)構(gòu)offsetslider-crankmechanism一、曲柄滑塊機(jī)構(gòu)CrankslidermechanismHΦ1>φ2

t1>t2V2>v1工作行程空回行程滑塊行程SlidestrokeHH曲柄轉(zhuǎn)速Crankspeedωω曲柄轉(zhuǎn)角crankangleφ1=180°+θφ2=180°-θ運(yùn)動(dòng)時(shí)間Exercisetimet1t2滑塊的平均速度TheaveragespeedofthesliderV1V2一、曲柄滑塊機(jī)構(gòu)Crankslidermechanism行程速比系數(shù):Travelspeedratiocoefficient：一、曲柄滑塊機(jī)構(gòu)Crankslidermechanism偏心曲柄滑塊機(jī)構(gòu)有極位夾角θ時(shí)，就有急回運(yùn)動(dòng)特性，而且θ角越大K值就越大，機(jī)構(gòu)的急回特性就越顯著。EccentriccrankslidermechanismwithextremepositionangleθAtthistime,thereisarapidreturnmotioncharacteristic,andθThelargertheangle,thegreatertheKvalue,andthemoresignificantthequickreturncharacteristicofthemechanism.一、曲柄滑塊機(jī)構(gòu)Crankslidermechanism對(duì)心曲柄滑塊機(jī)構(gòu)有急回特性嗎?Doesthecentercrankslidermechanismhaveaquickreturncharacteristic?極位夾角θ=0，行程速比系數(shù)K=1。Polarangleθ=0,travelspeedratiocoefficientK=1.Thecenteringcrankslidermechanismhasnoreturncharacteristic對(duì)心曲柄滑塊機(jī)構(gòu)無(wú)急回特性。一、曲柄滑塊機(jī)構(gòu)Crankslidermechanism曲柄滑塊機(jī)構(gòu)的運(yùn)動(dòng)特性Kinematiccharacteristicsofcrankslidermechanism死點(diǎn)位置dead-centerposition2.死點(diǎn)Deadpoint一、曲柄滑塊機(jī)構(gòu)Crankslidermechanism當(dāng)滑塊為主動(dòng)件，存在兩個(gè)死點(diǎn)位置。Whenthesliderisanactivecomponent,therearetwodeadcenterpositions.連桿和曲柄共線時(shí)，過(guò)鉸鏈中心A的力，對(duì)A點(diǎn)不產(chǎn)生力矩，不能使曲柄轉(zhuǎn)動(dòng)。Whentheconnectingrodandthecrankarecollinear,theforcepassingthroughthecenterAofthehingedoesnotgeneratetorqueatpointAandcannotcausethecranktorotate.死點(diǎn)位置dead-centerposition一、曲柄滑塊機(jī)構(gòu)Crankslidermechanism曲柄滑塊機(jī)構(gòu)的應(yīng)用：Theapplicationofcrankslidermechanism內(nèi)燃機(jī)氣缸一一對(duì)心曲柄滑塊機(jī)構(gòu)Internalcombustionenginecylinder--centricslider-crankmechanism一、曲柄滑塊機(jī)構(gòu)Crankslidermechanism曲柄滑塊機(jī)構(gòu)的應(yīng)用Theapplicationofcrankslidermechanism自動(dòng)送料裝置一一偏心曲柄滑塊機(jī)構(gòu)Automaticfeedingdevice-eccentriccrankslidermechanism一、曲柄滑塊機(jī)構(gòu)Crankslidermechanism2偏心輪機(jī)構(gòu)EccentricwheelmechanismTWO二、偏心輪機(jī)構(gòu)Eccentricwheelmechanism曲柄搖桿機(jī)構(gòu)Crank-rockermechanism工程中常將轉(zhuǎn)動(dòng)副的半徑擴(kuò)大至超過(guò)曲柄長(zhǎng)度變成圓盤，此偏心圓盤稱為偏心輪。曲柄為偏心輪結(jié)構(gòu)的連桿機(jī)構(gòu)稱為偏心輪機(jī)構(gòu)。Inengineering,theradiusoftherotatingpairisoftenexpandedbeyondthelengthofthecranktobecomeadisc,whichiscalledaneccentricwheel.Theconnectingrodmechanismwithaneccentricwheelstructureiscalledaneccentricwheelmechanism二、偏心輪機(jī)構(gòu)Eccentricwheelmechanism二、偏心輪機(jī)構(gòu)Eccentricwheelmechanism曲柄搖桿機(jī)構(gòu)的演化一一偏心輪機(jī)構(gòu)Theevolutionofcrankrockermechanism-eccentricwheelmechanism二、偏心輪機(jī)構(gòu)Eccentricwheelmechanism偏心輪機(jī)構(gòu)的應(yīng)用Theapplicationofeccentricwheelmechanism剪床shearingmachine機(jī)構(gòu)的演化方法:選擇機(jī)構(gòu)中不同的構(gòu)件為機(jī)架。Mechanismevolutionmethod:Selectdifferentcomponentsinthemechanismasframes.(a)對(duì)心曲柄滑塊機(jī)構(gòu)(b)導(dǎo)桿機(jī)構(gòu)(c)搖塊機(jī)構(gòu)(d)定塊機(jī)構(gòu)centricslider-crankmechanismguide-barmechanismShakermechanismBlockfixingmechanism二、偏心輪機(jī)構(gòu)Eccentricwheelmechanism3導(dǎo)桿機(jī)構(gòu)GuiderodmechanismTHREE三、導(dǎo)桿機(jī)構(gòu)Guiderodmechanism取曲柄滑塊機(jī)構(gòu)中原曲柄為機(jī)架構(gòu)成導(dǎo)桿機(jī)構(gòu)。原曲柄2為主動(dòng)件，若I3<I2，導(dǎo)桿1作往復(fù)擺動(dòng)，稱為擺動(dòng)導(dǎo)桿機(jī)構(gòu)。Taketheoriginalcrankofthecrankslidermechanismastheframetoformaguiderodmechanism.Theoriginalcrank2isanactivecomponent.IfI3<I2,theguiderod1oscillatesbackandforth,whichiscalledaswingingguiderodmechanism擺動(dòng)導(dǎo)桿機(jī)構(gòu)oscillatingguide-barmechanism三、導(dǎo)桿機(jī)構(gòu)Guiderodmechanism取曲柄滑塊機(jī)構(gòu)中原曲柄為機(jī)架構(gòu)成導(dǎo)桿機(jī)構(gòu)。Taketheoriginalcrankofthecrankslidermechanismastheframetoformaguiderodmechanism.原連桿3為主動(dòng)件，若I3≥I2，導(dǎo)桿1作整周運(yùn)動(dòng)，稱為轉(zhuǎn)動(dòng)導(dǎo)桿機(jī)構(gòu)。Theoriginalconnectingrod3isanactivecomponent.IfI3≥I2,guiderod1movesinafullcircle,whichiscalledarotatingguiderodmechanism.擺動(dòng)導(dǎo)桿機(jī)構(gòu)oscillatingguide-barmechanism4定塊機(jī)構(gòu)FixedblockmechanismFOUR曲柄滑塊機(jī)構(gòu)中，如取滑塊為機(jī)架，則該機(jī)構(gòu)演化成定塊機(jī)構(gòu)。Inthecrankslidermechanism,iftheslideristakenasaframe,themechanismevolvesintoafixedblockmechanism.四、定塊機(jī)構(gòu)Fixedblockmechanism定塊機(jī)構(gòu)Fixedblockmechanism手壓抽水機(jī)Handpresswaterpump5搖塊機(jī)構(gòu)Shak