变频驱动风机膜片联轴器损坏故障原因分析

Fault Analysis of Laminated Membrane Coupling of Fan with Variable-frequency Drive

针对风机变频改造后发生的膜片式联轴器膜片损坏故障问题,通过测试传动轴动态扭矩信号,将其作用到膜片上,计算得到膜片所承受的拉应力。试验发现,变频改造后风机在一定转速区间运行时,联轴器所承受的扭矩出现了大幅脉动,导致膜片承受的拉应力出现大幅波动,波动幅度超过平均值。根据膜片联轴器工作特点,采用局部应力-应变法计算脉动扭矩作用下膜片疲劳寿命。试验和计算结果表明,变频调速后风机传动轴上出现的扭矩脉动对膜片寿命的影响较大。扭矩脉动情况下,膜片疲劳强度不够,容易出现疲劳损伤。

The tensile stress of the membrane was calculated using the measured shaft dynamic torque signal for the analysis of the reason of membrane damage after the fan with variable frequency drive modification. Test result shows that large toque pulsation occurred on the coupling when the fan runs in certain speed zone. It causes large tensile stress pulsation of the membrane thereafter. The amplitude of the pulsation stress is larger than that of the mean stress. The local stress-strain method was used to calculate membrane fatigue life according to the work condition of the membrane coupling. It is found that there is large influence of the pulsation torque on the fatigue life of membrane. Membrane fatigue strength is not enough in case of torque with large pulsation. The membrane is easy to be damaged.