本文件规定了用于渐开线外或内直齿轮和斜齿轮的齿弯曲应力计算的基本公式，外齿轮的轮辋厚度sR>0.5 HT，内齿轮的轮辋厚度sR>1.75 MN。在使用中，内齿轮可能会经历齿弯曲疲劳以外的失效模式，即从齿根直径开始并径向向外发展的断裂。本文件没有针对除齿弯曲疲劳以外的失效模式提供足够的安全性。所有载荷对齿根应力的影响都包括在内，只要它们是齿轮传递的载荷的结果，并且只要它们可以定量评估。 本文件包括基于测试和理论研究的程序，如Hirt[11]、Strasser[14]和Brossmann[10]的程序。结果与其它方法（文献[5]、[6]、[7]和[12]）吻合较好。给定的公式适用于齿形符合ISO 53中标准化的基本齿条的正齿轮和斜齿轮。如果虚拟接触比ε α n小于2.5，它们也可用于与其他基本齿条共轭的齿。 基于允许弯曲应力确定的负载能力被称为“齿弯曲强度”。结果与该范围内的其他方法非常一致，如ISO 6336的范围？1. 如果此范围不适用，请参考ISO 6336-1:20 19第4条。

This document specifies the fundamental formulae for use in tooth bending stress calculations for involute external or internal spur and helical gears with a rim thickness s_R > 0,5 h_t for external gears and s_R > 1,75 m_n for internal gears. In service, internal gears can experience failure modes other than tooth bending fatigue, i.e. fractures starting at the root diameter and progressing radially outward. This document does not provide adequate safety against failure modes other than tooth bending fatigue. All load influences on the tooth root stress are included in so far as they are the result of loads transmitted by the gears and in so far as they can be evaluated quantitatively. This document includes procedures based on testing and theoretical studies such as those of Hirt^[11], Strasser^[14] and Brossmann^[10]. The results are in good agreement with other methods (References [5], [6], [7] and [12]). The given formulae are valid for spur and helical gears with tooth profiles in accordance with the basic rack standardized in ISO 53. They can also be used for teeth conjugate to other basic racks if the virtual contact ratio ε_αn is less than 2,5. The load capacity determined on the basis of permissible bending stress is termed "tooth bending strength". The results are in good agreement with other methods for the range, as indicated in the scope of ISO 6336？1. If this scope does not apply, refer to ISO 6336-1:2019, Clause 4.