油膜失稳引起的轴承碰摩故障研究

On the Rub-Impact Fault of Bearings Due to Oil Film Instability

为了研究油膜失稳和转子-轴承碰摩两种单一故障相互作用形成的耦合故障,利用转子实验台模拟油膜失稳引起的轴承碰摩故障,采集发生此故障时转子系统升降速过程的振动信号.利用三维谱振图、重排小波尺度图、频谱图和轴心轨迹图对竖直方向振动信号进行分析,结果表明:重排小波尺度图可以很好地提取轴承碰摩时的时间和频率信息.当转子系统发生二者耦合故障时,油膜失稳占主导地位,油膜失稳引起的碰摩会产生转频和涡动频率的组合频率成分.此外,由于不可公约的组合频率出现,轴心轨迹变得混乱不规则.

To investigate systematically the coupling fault caused by the interaction between oilfilm instability and rotor-bearing rub-impact, the coupling fault was simulated on a rotor test rig with the vibration signals acquired from rotor＇s speed up/down. The vibration signals in vertical direction are analyzed by 3D-waterfall spectrum, reassigned wavelet scalograms, amplitude spectrum and axial trajectory. The results show that the reassigned wavelet scalogram can extract well the time and frequency information on the rub-impact fault. When the coupling fault of rubimpact with oil film instability occurs, the oil film instability plays a major role in the rotor system, and the rub-impact cau^d by oil film instability will result in the two combination frequency components due to rotating and oil whirling. In addition, axial trajectory is found irregular and chaotic because there is no common factors found in the combined frequencies, which make them irreducible.