Simple Diagnosis and Precise Diagnosis Method Of Roller Bearings Fault
In the process of simple diagnosis of roller bearings using vibration, usually, the measured vibration value (peak value, practical value, etc.) is compared with a predetermined judgment standard. The vibration value is given based on whether the measured vibration value exceeds the norm. To determine whether the bearing has failed, to determine whether the further precision diagnosis is required. The judgment criteria for the simple determination of rolling bearings can be roughly divided into three types:
1. Absolute judgment standard: It is a total value used to judge whether the measured vibration value exceeds the limit.
2. Relative judgment standard: the same part of the bearing is periodically tested for vibration and compared according to time. The vibration value of the bearing without failure is the standard, based on the ratio of the measured vibration value to the reference vibration value Diagnostic criteria.
3. Analog judgment standard: it is a standard to test several bearings of the same model under the same conditions at the same location and compare the vibration values with each other to judge.
Precise diagnosis method of rolling bearing fault
The vibration frequency components of rolling bearings are vibrant, containing both low-frequency components and high-frequency components, and each specific fault corresponds to a particular frequency component. The task of precision diagnosis is to separate specific frequency components by appropriate signal processing methods, thereby indicating the existence of particular faults.
Low-frequency signals refer to vibrations with frequencies below 8 kHz. Generally, acceleration sensors are used to measure the vibration of rolling bearings, but the vibration speed is analyzed for low-frequency signals.
The frequency range of the intermediate frequency signal is 8kHz-20kHz, and the frequency range of the high-frequency signal is 20kHz-80kHz. Because the acceleration can be directly analyzed for the middle and high-frequency signals, the sensor signal passes through the charge amplifier, instantly removes the low-frequency signal through the high-pass filter, then demodulates it, and finally performs frequency analysis to find the characteristic frequency of the message.
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