基于应力波与小波分析的低速滚动轴承故障诊断研究

Study on fault diagnosis of low-speed rolling bearing using stress waves and wavelet analysis

低速滚动轴承结构和工作条件特殊,故障机理复杂,诊断难度较大。本文根据低速滚动轴承的故障特性,提出了利用应力波与小波分析进行低速滚动轴承故障诊断的方法。首先以低速运转Cooper轴承系列01B 65 EX滚子轴承为例,建立了完好和故障低速滚动轴承的三维整体接触计算模型,运用有限元软件对其进行了全面、精确的分析,包括内圈故障模型的最大应力和应变及各元件之间的接触应力,将发生故障前后的内圈外表面应力应变分布规律以及接触应力分布规律进行比较。然后在应力波实验的基础上,选择db6母小波、尺度j=4对实验所采集的数据信号进行小波变换,从而诊断出了轴承故障,说明应力波和小波分析是诊断低速轴承故障的有效方法。

Fault diagnosis of the low-speed rolling bearings is difficult, due to the reasons of the special structure, the peculiar working condition and the complex fault mechanism. Due to the fault features of the low-speed rolling bearings, in this paper, by applying stress waves and wavelet analysis, a new method for the fault diagnosis of those rolling bearings was presented. Firstly, the 01B65EX Cooper rolling bearing with low speed is taken as an example, and the three-dimension contact models for the good and inner race fault bearings were set up, which is studied through finite element method, and then the stress, the strain and the contact stress distribution are then given. The stress and strain distribution law of the outer race and the contact stress distribution law of the interface on good and fault bearing were compared. Then on the basis of the stress wave analysis, the wavelet transform of data signals that are collected in the experiments are carried out, for which the db6 wavelet with 4 scales is employed. Finally the characteristic frequencies of the stress waves with the simulative faults are extracted. The fault of low-speed rolling bearing is well diagnosed. Results show that stress wave and wavelet analysis is an effective method for diagnosing the fault of low-speed machinery.