本文给出公法线长度最佳跨越齿数K的计算方法。该“最佳”的含义是使实际的测量接触点位置与所希望的位置最靠近。一、直齿轮1．通常关于公法线长度的计算和验算1）按齿厚计算公法线长度W式中K为跨越齿数；Pb为基节，且Pb=πmcosα；Sb为基圆弧齿厚，且Sb＝cosα（S＋mZinvα） In this paper, we give the calculation method of the best length of public normal across the tooth number K. The “best” means that the actual measured touch point position is closest to the desired position. First, the spur gear Usually on the calculation and verification of the length of the common normal 1) calculated by the tooth thickness of the normal length W where K is the number of crossed teeth; Pb for the base section and Pb = πmcosα; Sb for the base arc tooth thickness, and Sb = cosα (S + mZinvα )