Gearbox fault detection using Hilbert transform and ZFFT
XIA Jun-zhong 1 LIU Yuan-hong 1 LI Shu-min 1 LENG Yong-gang 2 SU Tao 1
1. Automotive Engineering Department, Academy of Military Transportation, Tianjin 300161, China; 2. School of Mechanical Engineering, Tianjin University, Tianjin 300072, China
Abstract：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.
2013, Vol. 32 
