参考答案：已知d₁=28mm、α=20°，m_x=2.5mm，z₁=2
根据米制蜗杆计算式得
d_a1=d1+2m_x=28mm+2×2.5mm=33mm
d_f1=d₁-2.4m_x=28mm-2.4×2.5mm=22mm
tanγ=p_z/πd₁=z₁m_xπ/πd₁=z₁m_x/d₁
=2×2.5mm/28mm=0.17857
γ=10.12459°=10°07’29"
S_x=πm_x/2=3.1416×2.5mm/2=3.927mm
s_n=(πmx/2)cosγ=(3.1416×2.5mm/2)cos10°07’29"
=3.866mm
[答] 蜗杆的齿顶圆直径d_a1为33mm，齿根圆直径d_f1为22mm，导程角γ为10°07’29"，轴向齿厚s_x为3.927mm，法向齿厚s_n为3.866mm。