Tooth fracture is a prevalent failure mode that is intimately related to the bending strength of gears. Among the myriad factors influencing gear bending fatigue life, the morphology of the tooth root transition curve stands out as a crucial one, intricately tied to the gear’s resistance to bending fatigue. However, despite its significance, related research efforts, particularly experimental studies that consider cost factors, are relatively scarce in the current research landscape. Therefore, this paper first theoretically examines the influence of the tooth root transition curve morphology on the bending stress of gear teeth. Subsequently, bending fatigue experiments are conducted on gears featuring three typical tooth root transition curve morphologies, and the S-N curves for gears with these different morphologies are summarized. The findings reveal that adopting the digging-root type tooth root transition curve processing method, coupled with appropriately increasing the radius of the tooth top transition curve on the rack cutter, suitably reducing the distance between the rack tooth profile line and the tangent of the tooth root transition curve, and meticulously controlling the roughness of the tooth root transition curve, will significantly enhance the bending fatigue strength and prolong the bending fatigue life of the gear.

中文翻译：

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齿根过渡曲线形态对齿轮弯曲疲劳寿命影响的研究


齿断裂是一种普遍的失效模式，与齿轮的弯曲强度密切相关。在影响齿轮弯曲疲劳寿命的众多因素中，齿根过渡曲线的形态是一个至关重要的因素，它与齿轮的抗弯曲疲劳性有着千丝万缕的联系。然而，尽管它很重要，但在当前的研究领域中，相关研究工作，特别是考虑成本因素的实验研究，相对稀缺。因此，本文首先从理论上考察了齿根过渡曲线形态对轮齿弯曲应力的影响。随后，对具有 3 种典型齿根过渡曲线形态的齿轮进行了弯曲疲劳实验，并总结了具有这些不同形态的齿轮的 S-N 曲线。研究结果表明，采用挖根型齿根过渡曲线处理方法，结合适当增加齿条刀上齿顶过渡曲线的半径，适当减小齿条齿廓线与齿根过渡曲线切线的距离，并精心控制齿根过渡曲线的粗糙度， 将显着提高齿轮的弯曲疲劳强度，延长齿轮的弯曲疲劳寿命。