利用时延相关解调法诊断滚动轴承的故障

 为诊断滚动轴承的故障,常常对其振动信号进行包络解调,以获取故障特征。但所测振动信号中,包含大量的噪声,严重地影响解调结果,使得滚动轴承的故障特征难以凸现。为此,利用时延相关解调法以实现降噪解调。该方法利用相关函数的降噪特性,首先对振动信号进行相关分析,得信号的自相关函数。然后对自相关函数适当延迟以尽量避开噪声影响,再进行Hilbert变换,以求得解调结果。实验证明在滚动轴承故障诊断中时延相关解调法与直接解调法相比,噪声影响大幅减小,故障信息得以凸现。

Detection and Diagnosis of the Rolling Element Bearing Fault by the Delayed Correlation-Envelope Technique

In order to review the defect signature of rolling element bearings, the vibration signals measured on them are usually demodulated by the envelope analysis, or say, Hilbert Transform. However, the defect signature obtained by this demodulation is often masked by noise. In this paper, a new method of demodulation, Delayed Correlation-Envelope analysis is established in order to suppress the noise. The autocorrelation functions of vibration signals measured on bearings and gearboxes are first computed, which will reduce the noise greatly, but not change the modulation signature of the signals. Then the autocorrelation functions are delayed for some time lags, which will reduce the noise further. The delayed autocorrelation is then demodulated by Hilbert Transform. The effect of time delay on the demodulation results is also discussed here. The effectiveness of this method is confirmed by experiments.