裂纹故障下细高齿齿轮齿根动应变研究

Dynamic Tooth Root Strain of High-Contact-Ratio Spur Gear with Crack Fault

为探究裂纹故障对细高齿齿轮齿根动应变的影响规律,采用集中质量法建立齿轮系统动力学模型,将故障下的时变啮合刚度作为输入,对系统动力学方程进行求解得到不同裂纹深度下的齿轮副动态啮合力。利用有限元法建立含裂纹故障齿轮结构动力学分析模型,结合轮齿承载接触分析确定裂纹故障下的齿间载荷分配关系,采用瞬态分析得到齿根应变时域历程,并对不同裂纹深度下的齿根动应变进行分析。仿真结果表明,当从动轮发生裂纹故障后,其齿根动应变故障特征主要表现为啮合区内齿根应变数值的变化,主动轮齿根动应变故障特征主要表现为齿根应变时域历程中出现周期性冲击及幅值衰减,在1.5 mm裂纹深度下主动轮齿根应变峰值因子相对变化量达到12.72%。

In order to investigate the effect of crack on the dynamic tooth root strain of high-contact-ratio spur gear,a dynamic model of a gear system is established using the lumped-mass method,and the dynamic meshing force is obtained by solving the system dynamic equation with the time-varying mesh stiffness under crack fault as the input.Based on the finite element method,a dynamic model of a gear structure with crack fault is established,the load sharing between gear teeth is calculated via the loaded tooth contact analysis method,and the time history of the tooth root strain is obtained by transient analysis method.The dynamic tooth root strain with different crack depths are analyzed.The results demonstrated that,when the driven gear cracks,its fault characteristics of dynamic tooth root strain are mainly manifested by the change of its value in meshing area,and the fault characteristics of dynamic tooth root strain of driven gear are mainly manifested by the periodic impact and amplitude attenuation in the time history of tooth root strain.Under the crack depth of 1.5 mm,the relative variation of the peak factor of the dynamic tooth root strain of driving gear reaches 12.72%.