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1、ChinaUniversityPetroleum,Beijing,2006-2007,Semester1Testpaper(A)ofMechanismsandmachineTheory.(Closedbook)No.1234567TotalScoreScoreClass Name StudentIDNo. 1.Inacrank-slidermechanismshowninthefigure,thecrankisthedrivinglink.thestrokeHoftheslideris50mm,thecoef
2、ficientoftraveloftravelspeedvariationK=1.5,theoffsete=20mm.Pleasecalculate:(20%)1)Thecrankacuteanglebetweenthetwolimitingpositions，2)Thedimensionsofcranka,couplerb，3)ThemaximumpressureangleaMAX.ofthemechanism，4)Willthedead-pointoccurifthesliderisdrivinglink?评分标准：本题每小题５分１）图画对二极限位置之夹角可得3分
3、，写出公式k=(180º+θ)/(180º-θ)可得４分。结果1分２）计算方法可不同，必要公式和中间过程4分，结果１分３）写对表达式即可得５分，位置对，但结果错误扣１分。４）答对得分，错不得分。2.Drawthekinematicdiagramofthemechanism.(8%)评分标准：每错一处运动副扣２分，未按比例画图不扣分3.Inthecombinedgeartrainshownbelow,Z1=17,Z2=68,Z3=23,Z4=19.Z4’=20,Z5=24.Findthetrainratioi15.(10%)Solution:Intheordinaryg
4、eartrain1-2：①Intheplanetarygeartrain3-4=4’-5-2:②③评分标准：１）公式①４分，公式中丢“—”扣1分，２）公式②5分３）结果1分。4.Thefig.shownisaninvolutespurgearset:thedrivinggear1rotatesatangularvelocityω1,ra1andra2aretheradiiofbothaddendumcircleofgear1andgear2respectively,rb1andrb2aretheradiiofbothbasecircleofgear1andgear2.
5、modulem＝4mm，pressureangleα＝20°，μl＝0.001m/mm.Drawinthefigureandpointoutthefollowing:(20%)1)TheactuallineofactionB1B2graphically,2)ThetheoreticallineofactionN1N2graphically,3)MeasuretheactuallineofactionB1B2,,Calculatethecontactratioεαaccordingthedefinitionofcontactratioεαea=B1B2/Pbpb=pmc
6、osa评分标准：１）找对B1B2即可得６分，否则不得分。２）找对N1N2可得6分，N1N2方向反扣２分３）量得B1B2可得2分，写出εα的定义式得６分5.Calculatethedegreeoffreedomofthemechanismshown(theformulashouldbegiven).Addtheserialnumberstothelinksandindicatecompoundhinge,passiveDOF,redundantconstraintbeforethecalculationoftheDOF.Whatistheconditionforthem
7、echanismstohavedeterminedmotion?(10%)评分标准n=8１分pL=11１分pH=1１分F=3n－2pL－pH=3×8-2×11-1４分＝1１分机构有确定运动的条件为：原动件数与机构的自由度数相等。１分指示对compoundhinge,passiveDOF,redundantconstraint共１分6.AmechanicalsystemrunsataperiodicfluctuatedspeedwithaangularperiodofφT=2π,arotatinglinkisselectedasanequivalent
