SH=1.0[σH]1=σHlim1ZNT1/SH=570×0.92/1.0Mpa=524.4Mpa[σH]2=σHlim2ZNT2/SH=350×0.98/1.0Mpa=343Mpa故得:d1≥76.43(kT1(u+1)/φdu[σH]2)1/3=76.43[1×50021.8×(6+1)/0.9×6×3432]1/3mm=48.97mm模数:m=d1/Z1=48.97/20=2.45mm根据课本表取标准模数:m=2.5mm(6)校核齿根弯曲疲劳强度σF=(2kT1/bm2Z1)YFaYSa≤[σH]i齿=6Z1=20Z2=120u=6T1=50021.8N·mmαHlimZ1=570MpaαHlimZ2=350MpaNL1=1.28×109NL2=2.14×108确定有关参数和系数分度圆直径:d1=mZ1=2.5×20mm=50mmd2=mZ2=2.5×120mm=300mm齿宽:b=φdd1=0.9×50mm=45mm取b=45mmb1=50mm(7)齿形系数YFa和应力修正系数YSa根据齿数Z1=20,Z2=120由表6-9相得YFa1=2.80YSa1=1.55YFa2=2.14YSa2=1.83(8)许用弯曲应力[σF][σF]=σFlimYSTYNT/SF由设计手册查得:σFlim1=290MpaσFlim2=210MpaYNT1=0.88YNT2=0.9试验齿轮的应力修正系数YST=2按一般可靠度选取安全系数SF=1.25计算两轮的许用弯曲应力[σF]1=σFlim1YSTYNT1/SF=290×2×0.88/1.25Mpa=408.32Mpa[σF]2=σFlim2YSTYNT2/SF=210×2×0.9/1.25MpaZNT1=0.92ZNT2=0.98[σH]1=524.4Mpa[σH]2=343Mpad1=48.97mmm=2.5mmd1=50mm
全文预览
