应用Hilbert变换和ZFFT提取变速器齿轮故障特征

变速器故障齿轮振动信号,调幅现象和调频现象同时存在,其频谱中包括啮合频率及其谐波、调制产生的耦合频率。Hilbert变换无法提供足够高的频率分辨率解调低频调制信号,为此提出复调制细化谱分析方法。通过变速器齿轮故障模拟实验,采集齿轮正常、轻微磨损和严重磨损时的稳态振动信号,对其进行Hilbert变换得到信号的包络,对包络信号进行复调制细化谱分析,得到齿轮轴转频基波及其谐波幅值。随着齿轮磨损程度的增加,齿轮轴转频基波及其谐波幅值明显增大,可作为齿轮磨损故障特征参数。

Gearbox fault detection using Hilbert transform and ZFFT

When a gear has a local fault, the vibration signal of the gearbox may contain amplitude and phase modulation, its spectrum contains meshing frequencies, their harmonics, and coupling frequencies generated by modulation. Hilbert transform (HT) has been shown to be useful for demodulation. However, it is unable to show frequencies clear enough for visual inspection. Therefore, the method of multiple modulation zoom spectrum analysis (ZFFT) is proposed. Using a gearbox dynamics simulator collected steady-state vibration signals of gear normal, mild wear and severe wear, extracted the envelope signals using the Hilbert transform and analyzed this envelope signals using ZFFT in order to gain the amplitudes of modulating signals and their harmonics. The results show that: with the increase of gear wear, the amplitudes of gear shaft rotating frequency and its harmonics increase significantly, can be used as the fault characteristic parameters of gear wear.