舌簧阀片加速寿命实验方法及失效检测技术研究

Investigation on accelerated life test method and failure detection technology of reed valve

舌簧阀片是全封闭往复式压缩机的易损部件,其工作稳定性和使用寿命直接决定整机的制冷性能、产品寿命和振动噪声。通过对往复式压缩机运动模型和舌簧阀片力学模型的研究,提出了一种以激励压差和激励频率为加速因子的舌簧阀片加速寿命实验方法,引入阀片升程极大值和极小值来评价加速因子的最佳取值范围,并基于声学诊断方法对实验中阀片的失效进行自动识别。实验验证装置的测试数据表明,正常阀片与失效阀片的声音信号通过集合经验模态分解(EEMD)与样本熵(SampEn)进行失效特征提取,两者的熵值特征向量具有明显的区别。通过欧氏距离对熵值特征向量的相似度进行测度,对加速寿命中阀片的失效进行判定,为舌簧阀片使用寿命的评估提供依据。

The reed valve is a vulnerable part of the hermetic reciprocating compressor.Its working stability and service life directly determine the refrigeration performance,product life and vibration noise of the whole machine.Through the study of the motion model of reciprocating compressor and the mechanical model of the reed valve,a method of accelerated life test of the reed valve is proposed with the excitation pressure difference and the excitation frequency as the acceleration factor.The maximum value and the minimum value of the valve lift are introduced to evaluate the optimum range of the acceleration factor.And automatic identification of valve failure in test based on acoustic diagnosis method.The test data of the experimental verification device shows that the characteristics are extracted from the sound signals of the normal and failure reed valves base on ensemble empirical mode decomposition(EEMD)and sample entropy(SampEn).The entropy characteristic vectors of both valves are distinctly different.The similarity of the entropy characteristic vectors is measured by the Euclidean distance,and the failure of the valve in the accelerated life is determined.The accelerated life is used to provide the basis for the evaluation of the service life of the reed valve.