柔性薄壁椭圆轴承故障特征频率的波动性分析

doi:10.3901/JME.2025.02.011

摘要/Abstract

摘要： 柔性薄壁椭圆轴承是谐波减速器的关键部件，其内、外圈的椭圆特性使得定转速下其故障特征频率不是一个定值，而是存在周期性波动，这种特性与普通滚动轴承完全不同。柔性薄壁椭圆轴承的椭圆特性还会引起背景周期性冲击，对故障周期性冲击产生极大的掩盖。利用Morlet小波与故障周期性冲击的波形相似性特性从柔性薄壁椭圆轴承混合冲击信号中提取故障周期性冲击，分析了连续Morlet小波对故障周期性冲击的特征提取机理，从理论上证明了Morlet小波对与其波形相似的故障冲击可以获得最佳的提取效果，而椭圆引起的背景冲击则会被极大抑制。利用Hilbert-Huang变换提取故障冲击的瞬时频率。对于内圈故障和外圈故障的柔性薄壁椭圆轴承，从它们的振动信号中准确提取到了故障频率的波动特性，证明了柔性薄壁椭圆轴承的故障特征频率在定转速下确实存在有规律的周期性波动，且其波动的频率是凸轮轴转频的二倍。对比分析了普通滚动轴承故障特征的瞬时频率，结果表明其不存在周期性波动。故障频率的周期性波动是柔性薄壁椭圆轴承的特有性质。

关键词: 柔性薄壁椭圆轴承, 故障特征频率, 频率波动, 瞬时频率

Abstract: Flexible thin-walled elliptical bearing (FTEB) is the key component of harmonic reducer, and the elliptical characteristics of the inner and outer rings make the fault feature frequency of FTEB show periodic fluctuation even when the bearing rotates at a fixed speed, which is completely different from that of ordinary rolling bearing. The elliptical characteristics of FTEB can also cause background periodic shocks, which can greatly cover up the fault periodic shocks. The Morlet wavelet is used to extract fault periodic shocks from the mixed shock signal of FTEB based on the waveform similarity between the Morlet wavelet and the fault periodic shocks. The fault periodic shock extraction mechanism of the continuous Morlet wavelet transform is analyzed, and it is theoretically proved that the Morlet wavelet can obtain the best extraction effect for the fault shocks similar to the wavelet waveform, while the background shocks caused by the ellipse will be greatly suppressed. The instantaneous frequency of the fault shocks is extracted by the Hilbert-Huang transform. For the FTEBs with inner ring fault and outer ring fault, the fluctuation characteristics of the fault frequency are accurately extracted from their vibration signals, respectively, and the results show that the fault frequency of the FTEB does have periodic fluctuations even when the bearing rotates at a constant speed, and the fluctuation frequency is twice the rotation frequency of camshaft. As a comparison, the instantaneous frequency of the fault shock of ordinary rolling bearing is analyzed, and the results show that there is no fluctuation. The periodic fluctuation of the fault frequency is the unique property of the FTEB.

Key words: flexible thin-walled elliptical bearing, fault feature frequency, frequency fluctuation, instantaneous frequency

中图分类号:

TN911
TP277

赵学智, 叶邦彦, 刘其洪, 陈统坚. 柔性薄壁椭圆轴承故障特征频率的波动性分析[J]. 机械工程学报, 2025, 61(2): 11-23.

ZHAO Xuezhi, YE Bangyan, LIU Qihong, CHEN Tongjian. Fluctuation Analysis of the Fault Feature Frequency of Flexible Thin-walled Elliptical Bearing[J]. Journal of Mechanical Engineering, 2025, 61(2): 11-23.

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