机械设计基础0

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1、机械设计基础0Coupling-connectingtwoshafts,passingmotionsandtorque・Youcan'topenitatwork・Clutch一same・Openatanytimeatwork.Brakes一一frictionresistanceforcesthemachinetostop.Slidingbearingfrictioncondition:dryfriction(nolubricant)boundaryfriction(twofrictionsurfaceadsorptionistheboundaryofth

2、ethinf订m)liquidfriction(two)frictionsurfacecompletelyseparatedbyliquidmixedfriction(betweenboundaryfrictionandthefrictionbetweenliquid)・Composition:shaftbearingbearinglinerlubricationsealingdevice.Axisfailuremode:wear・Thepurposeoflubricationistoreducethefrictionpowerconsumption,r

3、educethewearrateandcoolthedustandrust・Lubricationmaterial:lubricatingoilandgrease・Dynamicpressureoilfilm:thepressureoilfilmformedintheclearaneeofthebearingbymeansofrelativemotionRollingbearingstructure:innerringrollingbodyiskept・Type:1self-aligningballbearing23Btaperrollerbearing

4、self-aligningrollerbearingcontactAngleincreased5thrustballbearinganddeepgrooveballbearingandangularcontactballbearingC15B40AC25degreesdegrees(ballaxialradialroller)Code:5type3widthseries(canbeomittedto0)series2,1,innerdiameter3mmrearsaidinternalstructuresealingdust/PO(don，t)level

5、0/P6sixlevelsofprecisionFailureofrollingbearings:fatigueandpermanentdeformation.Calculationprinciples:generalworkundertheconditionsofrotaryrollingbearingcontactfatiguelifecalculationandstaticstrengthcalculation,theswingorlowspeedonlystaticstrengthcalculation,highspeedcalculationa

6、ndcheckofbearinglimitspeedforlife・Loadcapacity:thebasicratedload:resistancetofatiguepointlossCisbasicload:resistanttoplasticdeformationBearinglife:thetotalnumberofturnsortimebeforethebearingoccursReliability:thepercentageofbearingsthatareabletoworkinalotofbearings・Thebearingbasic

7、ratinglifeLIO:abatchofthesamebearing,underthesameoperatingconditions,90%ofthebearingsdonotshowtheoperationtimeorrevolutionofthefatiguepoint・EquivalentdynamicloadP:r:radialloada:axialloadfr/fa>echartable〈二ey=0,x=lBearinglife:theballbearinglifeexpectancyindex:ballbearing3rollerbear

8、ing10/3Slidingbearingcompareswithrolling