On the basis of the first envelope, the paper stresses on the tooth contact analysis of the second envelope, and the equations of a worm and a wormwheel flanks are derived.
本文在第一次包络的基础上，着重进行了二次包络齿面接触分析，推导出了蜗杆和蜗轮齿面方程。
2
The equabions on tooth shape of internal gear by means of envelope method is derived and the pressure angle, inflection point, curvature, topcut are analysised in detail.
用包络法导出了内齿轮的齿形方程，对压力角、曲率、拐点、顶切进行了详细分析，并给出了计算公式。
3
Upper envelope model is derived from the characteristics of our price index. This paper is of extensive practical value.