说明：  做课程设计的时候自己编写的，用来验证选择的齿数是否满足强度要求。 根据《机械设计课程设计》 王军 田同海 何晓玲著这本书上的公式编写。
(When writing the course design, I wrote it to verify that the number of teeth selected meets the strength requirements. According to the formula design of mechanical design, Wang Juntian and Hai He Xiaoling wrote the formula in this book.)