校核齿根弯曲疲劳强度载荷系数重合度系数 Y?=0.25+0.75//Y?=0.68
齿间载荷分配系数：表12.10page217
KF?=1/Y?=1/0.68 KF?=1.47
齿向载荷分布系数：图12.14page219 b/h=85/(2.25×2.5)=15.1
KF?=1.38
载荷系数：K=KAKvKF?KF?=1.5×1.2×1.47×1.38 K=3.65
齿形系数,图12.21page229 YFa1=2.51
YFa2=2.19
应力修正系数,图12.22page230 YSa1=1.63
YSa2=1.82
许用应力,[?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=213Mpa
<[?F1]
F2=F1YFa2YSa2/YFa1YSa1
=213×2.19×1.8/2.46×1.65?F2=207Mpa
<[?F2]
安全计算主要尺寸