m(Z1+Z2)=2aZ1=2a/[m(1+i12)]=20rd1=0.5mZ1+m=55rf1=0.5mZ1-1.25m=43.75rb1=rcosα=0.5mZ1cosα=46.985
经计算：小轮齿数z1=20，齿顶园直径da1=110，齿根直径df1=87.5，齿距p=15.708，基圆直径db1=93.96926208 。
