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1、关于凸轮的外文资料ELEMENTSOFCAMDESIGNHowtoplanandproducesimplebutefficientcamsforpetrolenginesandothermechanismsCamsareamongthemostversatilemechanismsavailable.Acamisasimpletwo-memberdevice.Theinputmemberisthecamitself,whiletheoutputmemberiscalledthefollower.Throughtheuseofc
2、ams,asimpleinputmotioncanbemodifiedintoalmostanyconceivableoutputmotionthatisdesired.SomeofthecommonapplicationsofcamsareCamshaftanddistributorshaftofautomotiveengineProductionmachinetoolsAutomaticrecordplayersPrintingmachinesAutomaticwashingmachinesAutomaticdishwas
3、hersThecontourofhigh-speedcams(camspeedinexcessof1000rpm)mustbedeterminedmathematically.However,thevastmajorityofcamsoperateatlowspeeds(lessthan500rpm)ormedium-speedcamscanbedeterminedgraphicallyusingalarge-scalelayout-Ingeneral,thegreaterthecamspeedandoutputload^th
4、egreatermustbetheprecisionwithwhichthecamcontourismachined.Camsinsomeformorotherareessentialtotheoperationofmanykindsofmechanicaldevices.Theirbest-knownapplicationisinthevalve-operatinggearofinternalcombustionengines,buttheyplayanequallyimportantpartinindustrialmach
5、inery,fromprintingpressestoreapingmachines.Ingeneral,acamcanbedefinedasaprojectiononthefaceofadiscorthesurfaceofacylinderforthepurposeofproducingintermittentreciprocatingmotionofacontactingmemberorfollower.Mostcamsoperatebyrotarymotion,butthisisnotanessentialconditi
6、onandinspecialcasesthemotionmaybesemi-rotary,oscillatoryorswinging.Evenstraight-linemotionoftheoperatingmemberispossible,thoughthetermcammaynotbeconsideredproperlyapplicableinsuchcircumstances.Mosttextbooksonmechanicsgivesomeinformationonthedesignofcamsandshowexampl
7、esofcamformsplottedtoproducevariousordersofmotion.Whereneithertheoperatingspeednorthemechanicaldutyisveryhigh,thereisagooddealoflatitudeinthenermissibledesignofthecamanditisonlynecessarytoavoidexcessivelysteepcontoursorabruptchangeswhichwouldresultinnoise,impactshoc
8、k,andsidepressureonthefollowerBut,withincreaseofeitherspeedorload,muchmoreexactingdemandsaremadeonthecam,callingforthemostcarefuldesignand