校核齿根弯曲疲劳强度齿形系数：
当量齿数Zv1=Z1/cos327/cos312036'12''=29
Zv2=Z2/cos381/cos312036'12''=87
图12.21page229 YFa1=2.55
YFa2=2.22
应力修正系数,图12.22page230 YSa1=1.62
YSa2=1.78
重合度系数Y?：=[1.88-3.2(1/Z1+1/Z2)]cos?
=[1.88-3.2(1/29+1/87)]cos12036'12''=1.69
Y?=0.25+0.75//Y?=0.69
螺旋角系数Y?：Y?=max(1-0/1200，1-0.25，0.75)
=max(1-1×12.60/1200,1-0.25×1,0.75)
Y?=0.9
载荷系数齿间载荷分配系数：表12.10page217
KF?=/cos2?b=1.69/cos212.60 KF?=1.75
齿向载荷分布系数：图12.14page219
b/h=83/(2.25×2.5)=12.3
KF?=1.36
载荷系数：K=KAKvKF?KF?=1.5×1.2×1.75×1.36 K=4.28
许用应力,（同直齿轮例题） [?F]=?FlimYNYX/sFmin
a.极限应力：图12.23page231?Flim1=600Mpa
Flim2=450Mpa
b.当量应力循环次数：
设3×106<NL<1010 则由表12.15page226 m=49.1
NL1=60?nth([(thi/th)(Ti/Tmax)m]
=60×1×1000×4800[0.2×149.1+0.5×0.549.1+0.3×0.249.1]
=5.76×107(与假设一致)
NL1=5.76×107
NL2=NL1/?=5.76×107/3 NL2=1.92×107
c.弯曲寿命系数：图12.24page232 YN1=0.95
YN2=0.97
d.尺寸系数：图12.25page232 YX=1.0
e.安全系数：表12.14page225 SFmin=1.25
f.许用应力：[?F1]=?Flim1YN1YX/SFmin=600×0.95×1.0/1.25 [?F1]=456Mpa
[?F2]=?Flim2YN2YX/SFmin=450×0.97×1.0/1.25 [?F1]=349MPa
校核
F1=203Mpa
<[?F1]
F2=F1YFa2YSa2/YFa1YSa1
=203×2.22×1.78/2.55×1.62?F2=194Mpa
<[?F2]
安全