齿轮泵故障机理分析及诊断方法研究

发布时间：2018-02-28 04:08

本文关键词： 流场分析齿轮泵失效最优分数阶阶次谱故障决策　出处：《山东理工大学》2017年硕士论文　论文类型：学位论文

【摘要】：齿轮泵作为液压系统的基础元件,其工作状况将直接影响整个液压系统乃至设备的平稳运行和可持续生产,故对齿轮泵故障机理及故障诊断研究具有重要意义。本文以齿轮泵为研究对象,综合流体动力学、动力学、信号处理以及信息融合等多学科理论对齿轮泵轮齿的工作状态进行分析,达到故障诊断和状态分析的目的。具体研究内容如下:(1)综合考虑齿轮泵内部流场与结构的特点,建立齿轮泵内部流场模型,通过内部流场参数特点分析流动特性,分析内部流场激励条件下常见冲击形式;研究齿轮泵轮齿结构特征,建立轮齿的动力学模型,在模态分析的基础上对齿轮副固有频率进行计算;结合流场模型和齿轮副动力学模型,对内部流场中常见的冲击诱导产生的轮齿失效进行相关的仿真和数值计算研究,分析在激励条件下齿轮齿面应力应变的分布,进一步对内部流场产生的激励诱导轮齿的失效机理进行分析研究,得到齿轮副在内部流场中的失效形式和诱导因素。(2)将基于最优分数阶傅里叶变换的阶次谱分析方法对齿轮泵启动过程的非平稳振动信号进行降噪和特征提取,并研究故障特征分量的特点。在利用分数阶傅里叶变换对振动信号进行降噪的过程中,提出利用粒子群算法进行分数阶阶次寻优的方法,与步长搜寻法相比,得到更加精确的数据结果,并大大减少阶次寻找过程的计算量。在特征分量分数阶域进行以能量聚集中心为滤波中心的带通滤波处理,较好的改善信号的信噪比。针对齿轮泵启动过程中的振动信号的非平稳特征,选用阶次谱分析对降噪后的信号进行分析,得到能够准确反映齿轮泵工作状态的特征信息。(3)针对齿轮泵故障决策过程中证据间冲突问题,对证据源中证据间的冲突程度问题进行改善,对证据间的冲突进行重新分配,并对证据模型进行相应的修正,解决证据间强烈冲突问题,保留证据中的有用信息。对齿轮泵的状态信息特征进行决策研究,与经典的证据理论的融合结果相对比,得到具有较高可信度的结论,为齿轮泵的故障诊断研究提供理论研究基础。通过对齿轮泵的故障机理研究,使齿轮泵失效分析更加明确、全面;利用振动信号对齿轮泵的故障进行研究,达到齿轮泵故障诊断及状态监测的目的。通过试验研究表明本文所提出的方法有效可行,与其他方法相比具有一定优势。
[Abstract]:Gear pump as the basic component of hydraulic system, its working condition will directly affect the smooth operation and sustainable production of the whole hydraulic system and even the equipment. Therefore, it is of great significance to study the fault mechanism and fault diagnosis of gear pump. In order to achieve the purpose of fault diagnosis and state analysis, the multi-disciplinary theories such as signal processing and information fusion are used to analyze the working state of gear pump teeth. The specific research contents are as follows: 1) considering the characteristics of internal flow field and structure of gear pump, Establish the internal flow field model of gear pump, analyze the flow characteristic through the characteristic of internal flow field parameter, analyze the common impact form under the internal flow field excitation condition, study the gear tooth structure characteristic of gear pump, establish the dynamics model of gear tooth. On the basis of modal analysis, the natural frequency of gear pair is calculated, combined with the flow field model and the gear pair dynamics model, the simulation and numerical calculation of the common impingement induced tooth failure in the internal flow field are carried out. The distribution of stress and strain on gear tooth surface under excitation condition is analyzed, and the failure mechanism of induced gear tooth induced by excitation in internal flow field is analyzed. The failure form and inductive factors of gear pair in internal flow field are obtained. The order spectrum analysis method based on optimal fractional Fourier transform is applied to de-noise and feature extraction of non-stationary vibration signal in gear pump starting process. In the process of using fractional Fourier transform to reduce the noise of vibration signal, a particle swarm optimization method for fractional order optimization is proposed, which is compared with step size search method. More accurate data results are obtained, and the computation of order finding process is greatly reduced. In the fractional order domain of characteristic components, a bandpass filter with the energy aggregation center as the filter center is carried out. Aiming at the non-stationary characteristic of vibration signal during gear pump start-up, the noise reduction signal is analyzed by order spectrum analysis. The characteristic information which can accurately reflect the working state of gear pump is obtained. Aiming at the conflict of evidence in the process of gear pump fault decision, the conflict degree of evidence in evidence source is improved, and the conflict between evidence is redistributed. The evidence model is modified to solve the problem of strong conflict between the evidence, and the useful information in the evidence is retained. The research on the characteristics of the gear pump's state information is compared with the fusion result of the classical evidence theory. A conclusion with high reliability is obtained, which provides a theoretical basis for the research of gear pump fault diagnosis. Through the research on the fault mechanism of gear pump, the failure analysis of gear pump is more clear and comprehensive. The fault diagnosis and condition monitoring of gear pump are achieved by using vibration signal. The experimental results show that the method proposed in this paper is effective and feasible and has some advantages compared with other methods.
【学位授予单位】：山东理工大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TH137.51

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