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Diagnosis method of rolling bearing failure

wallpapers News 2020-12-17
The vibration frequency components of rolling bearings are very rich, including both low-frequency components and high-frequency components. Each specific fault corresponds to a specific frequency component. The task of an accurate diagnosis is to separate specific frequency components through appropriate signal processing methods to indicate the existence of specific faults.
 
Accurate diagnosis method of rolling bearing failure
 
1. Low-frequency signal analysis method
 
Low-frequency signals refer to vibrations with a frequency lower than 8kHz. Generally, acceleration sensors are used to measure the vibration of rolling bearings, but the vibration speed of low-frequency signals is analyzed. Therefore, the acceleration signal needs to pass through a charge amplifier, and then the speed signal is converted by an integrator, and then the high-frequency signal is removed by a low-pass filter with a high cut-off frequency of 8kHz, and finally, frequency component analysis is performed to find the characteristic frequency of the signal. diagnosis.
 
2. Demodulation analysis method of the medium and high-frequency signal
 
The frequency range of the intermediate frequency signal is 8kHz-20kHz, and the frequency range of the high-frequency signal is 20kHz-80kHz. Since the acceleration of the high-frequency signal can be directly analyzed, the sensor signal passes through the charge amplifier and directly through the high-pass filter to remove the low-frequency signal, then demodulates it, and finally performs frequency analysis to find the characteristic frequency of the signal.
 
Simple diagnosis method of rolling bearing failure
 
In the process of simple diagnosis of rolling bearings by vibration, the measured vibration value (peak value, effective value, etc.) is usually compared with a certain predetermined criterion, and it is given according to whether the measured vibration value exceeds the standard To determine whether the bearing is faulty, to determine whether the further precise diagnosis is required. The judgment criteria for the simple diagnosis of rolling bearings can be roughly divided into three types:
 
1. Absolute judgment standard
 It is the absolute value used to judge whether the measured vibration value exceeds the limit;
 
2. Relative judging standard
The same part of the bearing is periodically inspected for vibration, and compared in chronological order, based on the vibration value of the bearing without failure, based on the ratio of the measured vibration value to the reference vibration value Diagnostic criteria;
 
3. Analogy judging standard
 It is a standard for testing several bearings of the same type in the same part under the same conditions and comparing the vibration values with each other for judgment.

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