機(jī)械設(shè)計(jì)外文翻譯-橢圓齒輪曲柄搖桿打緯機(jī)構(gòu)的運(yùn)動(dòng)學(xué)分析及試驗(yàn)研究【中文2867字】【PDF+中文W,中文2867字,機(jī)械設(shè)計(jì),外文,翻譯,橢圓,齒輪,曲柄,搖桿,打緯,機(jī)構(gòu),運(yùn)動(dòng)學(xué),分析,試驗(yàn),研究,中文,2867,PDF Received date:2010-01-19Foundation items:National Natural Science Foundation of China(No 50875243);Zhejiang Technique Innovation Group of Modern TextileMachinery，China(No 2009R50018);Foundation of Education Department of Zhejiang Province，China(No Y201019088);Foundation ofNew Textile R D Emphasised Laboratory of Zhejiang Province，China(No 2009FZD004)*Correspondence should be addressed to CHEN Jian-neng，E-mail:jiannengchen zstu edu cnKinematic Analysis and Test Study of Elliptic-Gear and Crank-Rocker Beating-UpMechanismZHAO Xiong(趙雄)，REN Gen-yong(任根勇)，CHEN Jian-neng(陳建能)*College of Mechanical Engineering and Automation，Zhejiang Sci-Tech University，Hangzhou 310018，ChinaAbstract:In order to analyze the kinematic performances ofelliptic-gear and crank-rocker(EGCR)beating-up mechanism，kinematic mathematic models of the mechanism were established，and an aided analysis and simulation software were compiled Thissoftware can display the kinematic characteristics and simulationmotion of the mechanism according to different parameters It alsosupplies a platform for human-computer interaction A group ofsatisfactory parameters were selected by the software A test bed ofEGCR beating-up mechanism was developed according to theseparameters The kinematic performances of the mechanism wereverified by high-speed video tape recorderKeywords:beating-upmechanism;elliptic-gear;crank-rocker;kinematicsCLC number:TS103 135Document code:AArticle ID:1672-5220(2011)02-0222-04IntroductionBeating-up mechanism is one of the key mechanisms of aloom It beats the weft which is inserted by weft-insertionmechanism to form the fabric Its function is to transform theconstant speed rotation of the looms spindle to the non-constant speed reciprocating swing of the sleyIn order toallow the weft-insertion mechanism to finish inserting thewefts，the sley of the beating-up mechanism should haveadequate dwell time or relative dwell time in the front positionThe performances of beating-up mechanism determine thefabricsquality，andalsodecidethequalityandcompetitiveness of a loom1 Nowadays，there are three general kinds of beating-upmechanisms:four-bar linkage beating-up mechanism，six-barlinkage beating-up mechanism，and conjugated cam beating-upmechanismGenerally，four-barlinkagebeating-upmechanism is the simplest mechanism with 65-75 relativedwell time Six-bar linkage beating-up mechanism has about120 relative dwell time It has more hinges which producelarger cumulative errors The dwell time of conjugated cammechanism is 220-240，but the conjugated cam mechanismneeds veryhigh precision machiningIf there are someprocessing errors it will cause certain vibration2-4 In this paper，a new type of beating-up mechanism basedon elliptic-gear and crank-rocker(EGCR)was produced5，and its kinematic mathematic models were established A testbed was developed and the kinematic performances of themechanism were verified by high-speed video tape recorder，which demonstrated that this new mechanism could meet therequirements of weft beating-up1EGCR Beating-Up MechanismFigure 1 shows the EGCR beating-up mechanism in itsinitial position O is one of the focuses of the active elliptic-gear 1 and the rotation centre of the looms spindle A is one ofthe focuses and the rotation centre of the driven elliptic-gear 2Crank AB(l1)is fixed on the driven elliptic-gear Rocker CD(l3)is driven by BC(l2)and swings reciprocally Sley DE(l5)is fixed with CD by axis D and swings reciprocallytogether with CD By optimizing the eccentricity k(the ratioof the elliptic-gears minor radius(b)to major radius(a)，the angle (the included angle between AD(l4)and crank ABwhen crank AB and linkage BC are collinear，that is the sleyDE will be in the front position)，(the included anglebetween the major axis of the active elliptic-gear and AO)，(the included angle between AD and x-axis)，and the lengthsoflinkagesincrank-rockermechanism，thekinematicperformances of this novel beating-up mechanism becomeexcellent，which are similar to those of the conjugated cambeating-up mechanism1 Active elliptic-gear;2 Driven elliptic-gear;DESleyFig 1EGCR beating-up mechanism with its initial position2Kinematic Mathematic Models ofEGCR Beating-Up Mechanism2 1Mathematical models of the driven elliptic-gearIn Fig 1，when the active gear 1 rotates anticlockwise at aconstant speed，gear 2 will rotate clockwise at a non-constantspeed Given the angular displacements of the active gear 1 1and driven gear 2 2，the distance from mesh point P to axis Ois r1and PA is r2 With calculation，thenr1=b2/(a+ccos 1)，(1)r2=b2/(a+ccos 2)，(2)where，c is the distance between the elliptic-gear center and thefocus;1ranges from 0 to 2，and 2from 0 to 26 According to the transmission principles of elliptic-gearsr1=2a r2，(3)222Journal of Donghua University(Eng Ed)Vol 28，No 2(2011)that is，cos 2=(a+ccos 1)b2(2a2+2accos 1 b2)cac(4)From Eq(4)，the relationship between 2and 1can beobtained According to the principles of gear transmission2=1r1r2(5)Given that the velocity of active gear is constant，2=1r1r2 r1r2r22=2a r2r221(6)TakingthederivativeofEqs(1)and(3)，r1=b2csin 1(a+ccos 1)21and r2=r1，so in Eq(6)r2=b2csin 1(a+ccos 1)21(7)2 2Kinematical models of rocker CDSince the crank is fixed on the driven elliptic-gear，itsangular velocity and angular acceleration are the same as thoseof the driven elliptic-gear That is to say，j1=2，j1=2，and j1=+2 From Fig 2，the following equations canbe deduced7 Fig 2Crank-rocker mechanismj2=arctanyC yBxC xB(8)j4=arctan(yB yDxB xD)(9)j3=arccos(l32+(xD xB)2+(yD yB)2 l222l3(xD xB)2+(yD yB)槡2)+j4(10)j2=VxBcos j3+VyBsin j3l2sin(j2 j3)(11)j3=VxBcos j2+VyBsin j2l3sin(j2 j3)(12)j 2=c1cos j3+c2sin j3l2sin(j2 j3)(13)j 3=c1cos j2+c2sin j2l3sin(j2 j3)(14)In Eqs(13)and(14)，c1=axB+l3j23cos j3 l2j22cos j2，(15)c2=ayB+l3j23sin j3 l2j22sin j2(16)2 3Kinematic models of E in x-axis direction onthe sley DEDisplacement equation:sxE=xD+lDEcos(j3)(17)Velocity equation:VxE=lDEj3cos(j3/2)(18)Acceleration equation:axE=lDEj32cos j3+lDEj 3jcos(j3/2)(19)3AidedAnalysisandSimulationSoftwareofMechanismandParameter Optimization3 1Aided analytical softwareThe visualization of the mechanism is analyzing andoptimizing process that can display more information of theprocess to users Users can observe the whole process and findout the essential parameters ofthe mechanismHuman-computer interaction analysis and optimization combine thevirtues of both human and computersHumans possess thecapabilities of illegible illation，judgment and innovation，which can help to dispose random events as well Meanwhile，computers are good at accurate calculation and repeative workHuman andcomputercanfullydisplaytheirrespectiveadvantages in human-computer interaction optimization Thussatisfactory parameters can be easily achieved8-10 Based on the above kinematic models of EGCR beating-upmechanism，an aided analysis and simulation software arecompiled which is shown in Fig 3 It can be used to analyzethe influences of different mechanism parameters and verifywhether there exist interferences among the components of themechanismFig 3Aided analysis and simulation software of mechanismWith this software，users can input mechanism parameterssuch as a，k，l1，l2，l3，l4，and rotary speed of the loomsspindle The mechanism motion simulation will be shown onthe left of the interface;the displacement，velocity，andacceleration curves of point E will be shown respectively on theright of the interface;the optimal value of will be shown onthe left-bottom of the interface The displacement curve showsthat dwell time in the rear position decreases as k increases;322Journal of Donghua University(Eng Ed)Vol 28，No 2(2011)meanwhile the acceleration curve shows that the maximalacceleration also decreases as k increasesFor kinematicperformances of the mechanism，k needs to be optimizedaccording to the requirements of the beating-up weft;l1，l2，l3，and l4also need to be modified by the user in company withk，so as to achieve ideal kinematic performances3 2Optimization results analysisOne of the most important performances of beating-upmechanism is the dwell time of sley Increasing mechanismparameter k can prolong dwell time，meantime the maximalacceleration increases remarkably，and the oversize fluctuationof acceleration will degrade mechanism dynamic performanceDesigner must therefore make a balance between prolongingdwell time and controlling acceleration fluctuationWith the above aided analysis and simulation software，agroup of parameters was obtained:=4，k=0 85，=135，a=71 233 mm，l1=40 mm，l2=100 mm，l3=180mm，l4=199 mm，and lDE=189 5 mm Based on theseparameters，when the loom has a speed of 300 r/min，thekinematical curve of the beating point E is shown in Fig 4When the beating-up mechanism is on the rear position，thedisplacement curve is almost flat The dwell time of sley isclose to 200(ranging from 92 to 285)，which will not leadto interference of the beating-up mechanism and weft-insertionmechanism In addition，during this period，the curves of thevelocity and acceleration of the sley are almost close to 0Therefore it will not cause vibration，which will benefit thewefts entery and exit from shed At the end of the beating-up，the maximaldisplacementis 85mmandthemaximalacceleration is 615 843 4 m/s2，which both can meet therequirements of the beating-up weftFig 4The kinematic curves of EGCR beating-up mechanism4Test StudyBased on the above parameters，a test bed of EGCRbeating-up mechanism is developed(Fig 5)Using the high-speed video tape recorder and video analysis software BlastersMAS，the displacement and velocity are obtained with loomspindlesrotaryspeedat100r/minTheoreticalandexperimental displacements of beating point E are shown inFig 6，and theoretical and experimental velocities of beatingpoint E are shown in Fig 7 The actual measured displacementcurve is consistent with the theoretical one，but the actualmeasured velocity curve shows some fluctuationThere aretwo reasons for this finding:the gap among the components ofthe mechanism causes vibration;the video analysis containserrors422Journal of Donghua University(Eng Ed)Vol 28，No 2(2011)5Conclusions(1)In this paper，the EGCR beating-up mechanism hadbeen producedIts kinematic mathematic models had beenestablished and an aided analysis and simulation software hadbeen compiled byvisual basicAgroup ofsatisfactoryparameters had been got by this software(2)A test bed of the EGCR beating-up mechanism wasdevelopedWiththevideotaperecorder，itskinematicperformances were verified This demonstrated the validity ofthe models and the feasibility of the mechanismReferences1Zhu S K，Gao W D Weaving MachineM 2nd ed Beijing:China Textile Apparel Press，2004:267-268(in Chinese)2Liang H S，Hu Q E，Wang G C，et al The Fuzzy OptimizationDesign ofthe Four-Link Weft Beat-Up Mechanism JMachine 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