【精品】复试专业课.doc

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1、2007年重庆大学机械工程学院工学硕士研究生复试试题（机械设计及理论，工程机械方向）试题说明本试题满分100分.第一部分为专业英语，满分50分；第二部分为专业综合，満分50分.时间90分钟.第一部分：专业英语（总分50分，1-10小题每题4.5分11-12小题每题2.5分）Readthefollowingpassageandsentences,makethebestchoiceforsomequestionsorcompletetheunfinishedstatementsAmechanismhasbeendef

2、inedbyReuleauxas<4acombinationofrigidorresistantbodiessoformedandconnectedthattheymoveuponeachotherwithdefiniterelativemotion.”Mechanismsformthebasicgeometricalelementsofmanymechanicaldevicesincludingautomaticpackagingmachinery,typewriters,mechanicaltoys,text

3、ilemachinery,andothers.Amechanismtypicallyisdesignedtocreateadesiredmotionofarigidbodyrelativetoareferencemember.Kinematicaldesignofmechanismsoftenisthefirststepinthedesignofacompletemachine.Whenforcesareconsidered^theadditionalproblemsofdynamics,bearingloads

4、,stresses,lubrication,andthelikeareintroduced,andthelargerproblembecomesoneofmachinedesign.Thefunctionofamechanismistotransmitortransformmotionfromonerigidbodytoanotheraspartoftheactionofamachine.Therearcthreetypesofcommonmechanicaldevicesthatcanbeusedasbasic

5、elementsofamechanism・1.Gearsystem,inwhichtoothedmembersincontacttransmitmotionbetweenrotatingshafts.Gearsnormallyareusedforthetransmissionofmotionwithaconstantangularvelocityratio,althoughnoncirculargearscanbeusedfornonunifbimtransmissionofmotion.Thekinematic

6、aldesignofgearingisprimarilyconcernedwithspecificationoftheshapeofcontactingtoothsurfacesinordertoachievethedesiredangularvelocityratio.■2.Camsystems,whereauniformmotionofaninputmemberisconvertedintoanonunifbrmmotionoftheoutputmember.Theoutputmotionmaybeeithe

7、rshaftrotation,slidertranslation,orotherfollowermotionscreatedbydirectcontactbetweentheinputcamshapeandthefollower.Thekinematicaldesignofcamsinvolvestheanalyticalorgraphicalspecificationofthecamsurfaceshaperequiredtodrivethefollowerwithamotionthatisaprescribe

8、dfunctionoftheinputmotion・Thesubjectofcamdesignishighlyspecializedtopic.1.Planeandspatiallinkagesarealsousefulincreatingmechanicalmotionsforapointorrigidbody.Linkagescanbeusedforthreetask