基于时频分析的内燃机曲轴轴承磨损故障的诊断研究

内燃机曲轴轴承所受到的冲击信号是非平稳、时变信号，用传统的诊断方法难以进行故障的早期发现和诊断．论文运用振动测试技术，测取不同间隙下主轴承座及机体上的振动信号，然后充分利用了小波包无冗余、无疏漏、正交地分解信号到独立的频带内的能力及时频分布对时变信号良好的描述能力，发展了一种基于小渡包的重分配平滑伪魏格纳维尔分布的时频分析方法．通过对振动信号进行了分析比较，其干扰项少而分辨率高，既能定性揭示曲轴轴承磨损故障的变化规律，又能定量地诊断该故障．

Time-Frequency-Distribution-Diagnosis-Based Research for Main Bearing Wear of Gasoline Engines

Vibration signals borne by different main bearing clearances are not stationary and time variant. It is difficult to early detect and diagnose by means of traditional methods. The different clearances of the main bearing of previously designed EQ6100 model gasoline engine are studied. Vibration signals are obtained from the main bearing cover and engine block. Based on the decomposition and reconstruction of wavelet packet to time variant signals and better characteristics of reassigned smoothed pseudo wigner ville distribution ( RSPWVD) , a time frequency analysis method is developed. It has little disturbance and good time frequency resolution for revealing the rules of change for main bearing wear clearances. At the same time, it is capable of quantitatively analyzing vibration signals.