框图的拟定本文只考虑直齿圆柱标准钢齿轮,热处理状态仅包括退火、正火或调质、整体淬火或表面淬火;对于普通机器,认定应力循环次数N(或当量应力循环次数Nd)足够大 The block diagram of this paper only consider the standard gear spur gear, heat treatment only includes annealing, normalizing or quenching, the overall quenching or surface hardening; for general machinery, that the number of stress cycles N (or equivalent stress cycle number Nd) is large enough