中介轴承复合故障动力学建模与振动特征分析

Dynamic modeling and vibration characteristic analysis of the inter-shaft bearing’s multiple point fault

准确获取中介轴承多点复合故障振动特征,对提高其故障诊断准确性具有重要意义。该研究基于非线性Hertz接触理论,采用时变位移激励函数描述滚子的多点局部缺陷,建立了中介轴承多点复合故障的4自由度动力学模型,分析了内圈多点故障、外圈多点故障和内外圈复合故障的动力学特性。搭建了中介轴承故障模拟试验台,开展中介轴承内圈多点故障、外圈多点故障与内外圈复合故障模拟试验,并采集振动信号,对所建立的动力学模型进行验证。研究表明,基于该研究建立的多点复合故障动力学模型计算的故障特征频率值与试验值的误差小于1%,仿真模拟的时域波形和包络谱中的故障成分分布规律与试验结果一致,证明所建内、外圈多点故障及内外圈复合故障动力学模型准确有效。

It’s very important to obtain the vibration characteristics of the multi-point composite fault of an inter-shaft bearing accurately for improving the bearing fault diagnosis accuracy. Based on the nonlinear Hertz contact theory, the multi-point local defects were described by the time-varying displacement excitation function. A 4 DOF dynamic model for multi-point composite faults of the inter-shaft bearing was established. The dynamic characteristics of the multi-point faults of inner ring, outer ring and complex rings were analyzed. A fault simulation experiment platform of the inter-shaft bearing was built, and the simulation tests on the inner ring multi-point fault, the outer ring multi-point fault and the inner and outer ring composite fault of the inter-shaft bearing were carried out. The vibration signals were collected to verify the established dynamic model. The results show that the error between the calculated fault characteristic frequency value and the experimental value is less than 1%. The distribution of fault components in the time domain waveform and envelope spectrum of the numerical simulation is consistent with the experimental results. The built dynamic models for multi-point faults in inner and outer rings and composite faults in inner and outer rings are accurate and effective.