准静态工况下斜齿轮裂纹扩展特性与寿命研究

Research on Crack Growth Characteristics and Life of Helical Gears under Quasi Static Conditions

齿轮的断齿行为通常由疲劳裂纹引起。为了研究齿根裂纹在齿轮传动过程中的扩展行为,基于线弹性断裂力学理论和有限元法,通过准静态工况下斜齿轮齿根裂纹的扩展轨迹,对裂纹扩展寿命进行了预测,并讨论载荷、裂纹初始角度、裂纹形状对初始裂纹应力强度因子的影响。结果表明:初始裂纹深度为0.2 mm,宽度为0.4 mm,沿齿宽方向扩展过程中达到一定长度时,裂纹开始沿齿顶方向扩展,直至裂纹扩展到失稳扩展阶段,预测裂纹扩展的循环寿命约为2.6×10^(6)次;初始裂纹Ⅰ型应力强度因子与载荷成正比关系,而裂纹形状会改变沿齿厚和齿宽方向应力强度因子的扩展速率。

The breaking behavior of gears is usually caused by fatigue cracks. In order to study the propagation behavior of tooth root cracks during gear transmission, based on linear elastic fracture mechanics theory and finite element method, the propagation trajectory of helical gear tooth root cracks under quasi static conditions was studied, and the crack propagation life was predicted. The effects of load, initial crack angle, and crack shape on the initial crack stress intensity factor are studied. The results show that the initial crack depth is 0.4 mm and the width is 0.2 mm. When it reaches a certain length in the process of extending along the tooth width, the crack starts to grow in the direction of the tooth tip until the crack expands to the instability growth stage. The cycle life of the crack growth is predicted. It is about 2.6×10^(6) times;the type I stress intensity factor of the initial crack is proportional to the load, and the crack shape will change the growth rate of the stress intensity factor along the tooth thickness and tooth width.