机械设计-斜齿轮强度

ChapterDesignofhelicalDr.LiuWen88392850Updated5/4/2012,1Key ysisofhelicalStrengthcalculationofhelical齿轮强度计算公式21Loadonhelicalgeartoothfrompower斜齿圆柱齿轮传动的受力分Fn1inthenormalplane(法面)Pabccanbe posedinto3components:Ft1,Fr1andFa1

Fr

3Loadonhelicalgeartoothfrompower斜齿圆柱齿轮传动的受力分Directionofforces各力的方向判Fr,Ft:thesameasthoseofspurFaLeftandRight-handrules左、右手定则fordrivinggearPresentationofforces:表示方法Driving Right- Left-

4

Contactfatiguestrengthofhelicalgear2K1bd1u1u斜齿2K1bd1u1u直齿轮:Amendmentstothe

ZE.ZH.Z1)1)Lengthofcontactline 接触线长度

x.a

cos

bZ2.cos Zbx：接触线总长度变化系数 Zε：重合度系Zb端面重合度端面重合度1.881Z2cos4-3a)a纵向重合度b纵向重合度bsinn

5Amendmentstothe

直:Z .Z2K1EHbd1Z .Z2K1EHbd1u1uZ cos2)Helixanglefactor 螺旋角系6Amendmentstothe

直:

ZE

.ZH

.Z2K1bd1u1u3)Curvatureradiusatthe2K1bd1u1u1 2cosb d1.cost

.u1u

--helical1 d1.cost

.u1u

--spurCurvatureradiusofhelicalgearincreasesandthecontactstressdecreasesP222图12.16按螺旋角查取7Calculationformulaforcontactfatigue接触疲劳强度的计算公4-4-3a(1-)a8Notesfortheabove2KT1u2KT1ubd1uH

ZE

.ZH

Designformula接触疲劳强度 u

ZE.Z.ZH.Z u ud

[H9HowtoHowto

ZE

.ZH

.u1

ZE.Z.ZH.Z)22KT1ubd2KT1ubd1uudH 1d3 1d3dHuuBendingfatiguestrengthofhelicalgeartooth斜齿轮弯曲疲劳强轮齿的失效形式:局部折断Bendingstrengthcheck弯曲强度

Fmm2KTYcos2n 2Y YYdZ1F]Designformula弯曲强度Comparedwithspur

F

F2KTY

m

Y

and

Z 1dF—canbeobtainedfromP229-1dF

Yβ—helixanglefactor螺旋角系see v vZcos31-0.25 1-Y

1,则按

1计算;若

0.75,则按

0.75计算;若30,则按30计算Ft YY Fnm2KTYcos2n 2Y YY ZF] 1)]cosZZv 0.25 vZcos3 4-3a)a端面重合度1.88 Z1Z2cosComparedwithspurYε—contactratiofactor重合度系注意:斜齿轮中，计算接触应力时的重合度系数Zε与计算弯曲应力的重合度系数Yε不同。前者使用实际齿数Z，后者使用当量齿数Zv计算时使用的重合度系HowtoHowto

F2KTY

m

Y1dF Z 1dF

HowtoHowto

F2KTY

m

Y1dF Z 1dF

nm3ψZ2YY FSelectionofdesignparameters设计参数的选 m,Z,

samea