基于时变零相位滤波的变转速滚动轴承故障诊断

针对变转速下齿轮箱中滚动轴承故障调制特征的提取与分离，提出了基于时变零相位滤波的变转速滚动轴承故障诊断方法。该方法先用线调频小波路径追踪(CPP)算法从齿轮箱滚动轴承故障振动信号中估计出齿轮啮合频率，由啮合频率除以齿数得到齿轮箱的转速，同时，采用Hilbert包络解调方法获取轴承故障振动信号的包络信号；然后根据获取的转速信息设计各阶时变零相位滤波器；再采用各时变零相位滤波器对包络信号进行分析，获取各调制信号；最后，利用转速信号对求取的各调制信号进行阶次分析，并根据各阶次谱来诊断滚动轴承故障。算法仿真和应用实例分析表明，该方法可有效提取和分离变速齿轮箱中滚动轴承的各阶故障调制特征。

Fault Diagnosis Method for Rolling Bearings under Variable Rotate Speed Based on Time-varying Zero-phase Filter

Aiming at the problems of extracting and separating fault modulation characteristics of rolling bearings from vibration signals of a gearbox under variable rotate speeds, a new fault diagnosis method for rolling bearings was proposed based on time-varying zero-phase filter. The gear mesh frequency was estimated from the vibration signals of faulted rolling bearings in gearbox by using chirplet path pursuit, and thus the shaft rotating speed of gearbox might be obtained by dividing the gear meshing frequency by the number of gear teeth, meanwhile, the analysis of Hilbert envelope demodulation was carried out to obtain the envelope signal of the vibration signals of faulted rolling bearings. And according to the shaft rotating speeds, each time-varying zero-phase filter was designed. Then each modulation signal was acquired by the analysis of time-varying zero-phase filter to the envelope signal. Lastly, the fault diagnosis of rolling bearings was carried out according to the order spectrum, which was obtained by using order analysis to each modulation signal on the basis of the shaft rotating speeds. Simulations and application examples indicate that the proposed method may effectively extract and separate each fault modulation characteristics of rolling bearings from a rotating speed changing gearbox.