滚动轴承课件

《滚动轴承课件》由会员上传分享，免费在线阅读，更多相关内容在行业资料-天天文库。

Chapter13Rolling-contactBearingsKeyTerms:rolling-contactbearingballbearingrollerbearingthrustbearing

1radialloadthrustloadbasicdynamicloadratingbasicstaticloadratingequivalentloadtheratedlifeexpectedlife

2

313.1TypesofRolling-contactBearingsandtheRepresentingCode1.ConstructionMaterials:GCr15、GCr15SiMn58~65HRCDdwidthouterringinnerringRetainerrollingelementouterringrace

42.ParametersContactangleLoadangleLimitingspeedMisalignmentCapacity:allowableangulardeviation

5

6

7

83.TypesofRolling-contactBearingAccordingtoloadingdirection:radialbearingsthrustbearingsangularcontactbearingsAccordingtorollingelementshapes:ballbearingsrollerbearings

94.TypesDouble-rowangularcontactbearings0

10Double-rowtaperedrollerbearings35

11Double-rowself-alignballbearings1

12Double-rowself-alignrollerbearings2

13Self-alignthrustbearings2

14Taperedrollerbearings3

15Double-rowdeepgroovebearings4

16Thrustbearings5

17

18Deepgroovebearings6

19Angularcontactbearings7

20Thrustrollerbearings8

21RollerbearingsN

22Double-rowrollerbearingsNN

23NeedlebearingsNA

24FourpointscontactbearingsQJ

25

265.NumbersofRolling-contactBearings(GB/T272-93)BearingDesignation:71206AC/P6/C2pre-symbolbasicnumberpostnumber

27BasicNumberFirst&second:innerdiameternumberd=065=30mmThird:diameternumber1－extra-lightseries2－lightseries3－mediumseries4－heavyseries

28Fourth:widthnumber0－narrowseries(omitted)1－normalseries2－wideseriesFifth:Typenumberseetable13.1

29PostNumberFirst:Internalconfigurationnumber70000：C：=150AC：=250B：=400Fourth:Tolerancelever/P2：2/P4：4/P5：5/P6：6/P6x－6x/P0－0(omitted)-

30sixth:freeclearancenumber/C1:1/C2:2/C0:0(omitted)/C3:3/C4:4/C5:5+Pre-symbolPartialsymbolofthebearing,e.g.L,K,R,etc.

31ExampleExplainthefollowingbearingcodes:6308，7211C/P5Solution6308－Forthediameterof40mm,deepgrooveballbearings,intheseries,Tolerance0,0GroupClearance7211C/P5－Theinsidediameteris55mm,theanglecontactballbearing,lightseries,angleofcontact=150,5levelcommondifference,0groupofwindage

326.TheChoicesoftheBearingTypesLoadLimitingSpeedMisalignmentCapacityMountandDismount

3313.2TheForcesandFailures1.Theloadinganalysis

34Fig.13.5theforcechangingprocedure

352.TheFailuretypesofrolling-contactbearing1)Pitting

362)Plasticdeformation

373)wear

384)breakage

39

405)burning

41

423.DesignCriterion1）forrevolutionbearings:calculatethefatiguelife2）forstaticorlowrevolutionspeedbearings:calculatethestaticstrength

4313.3TheSelectionofRolling-contactBearings1.Thefatiguelifeofrolling-contactbearings1)LifeThelifeistheworkingrevolutionsorhoursbeforethepittingoccursonthebearing.2)RatedlifeL10,LhTheratedlifeisthelifethat90%ofthebearingswouldachievesuccessfullyunderaratedload.

44RatedLifeofDifferentReliability

453)BasicdynamicloadratingCThebasicdynamicloadratingistheloadtowhichthebearingscanbesubjectedwhileachievingaratedlifeof106r.CrorCa4)BasicstaticloadratingC0Thebasicstaticloadratingistheloadthatthebearingscanwithstandwithoutpermanentdeformationofanycomponent.C0rorC0a

465)Load/liferelationshipP/kNL10/(106r)3101C=3,forballbearings;=10/3,forrollerbearings.

47——checkformulaLh——theratedlifeC——basicdynamicloadratingP——equivalentloadn——rotationalspeed(rpm)——3or10/3

48——designformulaL'h——theexpectedlifeC——basicdynamicloadratingP——equivalentloadn——rotationalspeed(rpm)——3or10/3

492.Equivalentloadofbearings1)Concept2)CalculationForradialloadonly:P=fpRForthrustloadonly:P=fpA

50Forradialandthrustload:P=fp(xR+yA)P——equivalentload;R——appliedradialload;A——appliedthrustload;fp——loadcoefficient,table13.4x——radialfactor,table13.3y——thrustfactor,table13.3

51

523.DeterminationofradialloadRAccordingtoforceequilibriumprinciple:

53=3000N

54

554.DeterminationofthrustloadA—forangularballbearingsandtaperedrollerbearings(1)Twomountingsofangularcontactbearings:FacetofaceBacktoback

56(2)Accordingtoequilibriumcondition:S1S2DerivedaxialloadS

57(3)Calculationofappliedthrustloadforangularcontactbearings

58(4)Procedure1)Drawdirectionsofderivedaxialloadandcomputeitsmagnitude;2)Accordingtodirectionofresultantaxialforcesonshaft,judgemovingtendencyofshaft,judge“loosenbearing”and“pressedbearing”;3)Theappliedthrustloadof“loosenbearing”isequaltoitsownderivedaxialload;4)Theappliedthrustloadof“pressedbearing”isequaltoalgebraicsumofotherthrustloads(exceptforitsownderivedaxialload).

59ExampleAsshownbelow,R1=10000N,R2=5000N,FA=2000N,S=0.68R.Find:A1=?A2=?12Solution

60DeterminationofthrustloadA—fordeepgrooveballbearingsRegardingthegulleyballbearing,itsaxialloadingAdecidedbytheexternalinfluenceonaxisaxialforceFA,aimsthebearing,itswithstandsaxialforceAistheexternalinfluenceonaxisaxialforce(A=FA),anotherbearingwithstandstheaxialforceiszero.

61ProcedureforBearingSelectionDeterminethedesignlifeL'hDeterminetheequivalentloadP=xR+yACalculatetherequiredbasicdynamicloadSelectabearingwithC(>Creq’d)andaborethatcloselymatchestheshaftdiameter.

62ProcedureforBearingLifeCheckDeterminethebasicdynamicloadratingDeterminetheequivalentloadP=xR+yACalculatetheexpectedlifeCheckthebearinglife

631.Theangularcontactbearings(7207C)areshownbelow,theyaresubjectedtoradialloadsR1=1500N,R2=875N,theappliedexternalthrustloadFA=400N,thederivedloadS=eR.ComputetheappliedthrustloadsA1,A2.

642.Thetaperedrollerbearingsareshownbelow，theexternalappliedloadFA=1030N,FR=6000N,n=1000r/min,loadcoefficientfp=1,thebasicdynamicloadratingC=34000N，Find：1)TheequivalentdynamicloadsP1,P2；2)Theratedlifeofbearings.

653.Twoangularcontactbearings7207ACaremountedbacktobackontheshaft,theappliedloadsonthegearsasknowthatisFt=2200N,Fr=900N,Fa=400N,thereferencediameterd=314mm,therotationalspeedn=520rpm,mediumshock,Findtheratedlifeofbearings.

6613.4MountingofBearings1.ToleranceandFitTheBasicShaftSystemclearancefitHoletolerance:H7,J7,Js7,etcTheBasicHoleSysteminterferencefitShafttolerances:k6,m6,n6,etc.

67

68“walkstheinnerloop”thescratch

69Heatcrack

70Hotadhesion

71“walkstheaddendumcircle”thescratch

721,inforbidstoraptheaddendumcircledirectlywiththeironhammer!2,forbidsthroughtherollingbodytransmissioninstallmentstrength!

73

74

75

76

77

782.DimensionsTheshoulderislowerthantheinnerloopaltitudehighly!

79Dismountofbearings

80

81

823.AxialRetainingofbearings1)innerraceretaining(a)(b)(c)RetainingringEndcapLocknut

832)outerraceretaining(a)(b)a)Retainingringb)Endcap

844.MountTypes1)Twobearingsretainedinonedirection

85

86C=0.2~0.4mm

872)Onebearingretainedintwodirections,onebearingfloatTheinnerloopisfixed,theaddendumcircleisnotfixed!

88

89Atthesametimeinnerloop,addendumcirclefixed!

90

91

92

93

943)Twobearingsfloat

9513.5PracticalConsiderationsinApplicationofBearingsFunction:1.Providealow-frictionfilm;2.Protectthebearingcomponentsfromcorrosion;3.Carryheatawayfromthebearingunit;4.Dispelcontaminantsandmoisturefromthebearing;Lubricant:greaseandoil:table13.51.Lubrication

962.Bears’Preloading

973.Sealing1)Contactsealinga)Feltcircleseal

98b)LipSeal

992)Non-contactSealinga)Groovesealb)Labyrinthseal

1004.ModifyClearance1)ByshimAttention:Thebevelgearmustadjusttheshaftingtheaxiallocation.method:Betweenadjustmentretainercupendsurfaceandbearingseatendsurfacefillingpiecethickness.

1012)Byscrew

1023)Bylocknut

1035.Stiffness

104DerivedAxialLoadSDirection:

105MagnitudeofDerivedAxialLoadTaperedRollerBearingAngularContactBallBearing70000C(a=15°)70000AC(a=25°)70000B(a=40°)S=R/(2Y)S=eRS=0.68RS=1.14R

106a)facetoface

107b)Backtoback

108

109TypicalShapesofaRollerroller

110RadialBearing:(a)、(b)=00ThrustBearing:(c)、(d)=45~900AngularContactBearing:(e)、(f)=0~450

111

112

113

114

115

116LifeDistributionChartAmountofnofailure/%190

117

118

119

120

121Angularcontactbearings7

122TheendThanks!