What should I do if the bearing always rings? Today's article will help you find the cause and how to deal with it.
01
Normal running bearing sound
If the bearing is in a good continuous rotation state, it will emit a low whining or buzzing sound. If there is a sharp hiss, squeak and other irregular sounds, it often indicates that the bearing is in a bad continuous rotation condition. Squeaky squeaking noises may be caused by improper lubrication. Improper bearing clearance can also cause metal rattle.
Dimples in the raceway of the bearing's outer ring cause vibrations and produce a smooth, crisp sound.
If there is intermittent noise, the rolling elements may be damaged. This sound occurs when the damaged surface is rolled over. If there is contamination in the bearing, it will often cause a hissing sound. Severe bearing damage can produce irregular and loud noises.
If it is caused by knocking scars during installation, it will also produce noise, which will vary with the speed of the bearing.
loud metallic noise
Reason 1: abnormal load, countermeasures: correct the fit, study the bearing clearance, adjust and load, and correct the position of the housing shoulder.
Reason 2: poor installation, countermeasures: machining accuracy of shaft and housing, improvement of installation accuracy and installation method.
Reason 3: Insufficient or unsuitable lubricant, countermeasure: add lubricant and choose appropriate lubricant.
Reason 4: The rotating parts are in contact. Countermeasure: Modify the contact part of the labyrinth seal.
regular noise
Reason 1: Indentation, rust or scars on the rolling surface due to foreign matter. Countermeasures: replace the bearing, clean the relevant parts, improve the sealing device, and use clean lubricant.
Reason 2: (after carburizing the steel) surface deformation, countermeasure: replace the bearing and pay attention to its use.
Reason 3: The raceway surface is peeled off. Countermeasure: replace the bearing.
irregular noise
Reason 1: The clearance is too large. Countermeasures: study the fit and bearing clearance, and modify the preload.
Reason 2: foreign matter intrusion, countermeasures: study and replace bearings, clean related parts, improve sealing devices, and use clean lubricants.
Reason 3: Spherical damage, peeling, countermeasure: replace the bearing.
02
Detection method and instrument for bearing abnormal noise
At present, there are two ways to detect abnormal noise of bearings. One is the noise detection method based on acoustics, and the other is the detection method based on vibration.
noise detection method
It is a direct measurement method of abnormal sound by using a high-quality microphone to extract bearing sound pressure signals at a certain distance and direction in a sound-absorbing environment where the basic noise is less than 20db, and extracting the abnormal sound components through a certain analysis method.
Vibration detection method
It is an indirect detection method for abnormal sound, and can be divided into qualitative detection method and quantitative parameter detection method. Among them, the qualitative detection method is divided into monitoring abnormal sound method and observing vibration waveform method. The quantitative parameter detection method refers to the evaluation of the abnormal sound of the bearing by using the measured parameter values related to the abnormal sound in the vibration signal of the tested bearing, such as the peak value and crest factor of the vibration.
Measuring instrument for measuring abnormal sound of bearings
There are many measuring instruments for measuring abnormal sound of bearings, such as: BANT-1 bearing abnormal sound monitor of Hangzhou Bearing Test Research Center; S092 bearing vibration (abnormal sound) measuring instrument of Shanghai Bearing Technology Research Institute; Luoyang Bearing Research Institute and Dalian Bearing S0910-Ⅲ jointly developed by the instrument factory. These bearing measuring instruments can measure the effective value of bearing vibration and can also measure the peak value, peak factor and pulse number reflecting the abnormal sound parameters of the bearing.
Correct storage method of bearings
1. Keep the original packaging and do not open it arbitrarily. If the packaging is found to be damaged, it must be opened and cleaned carefully, and the packaging should be re-oiled.
2. The relative humidity in the storage room should not exceed 60%, and the temperature difference should not be too large. The bearings in the original packaging can be stored for several years. For sealed bearings or bearings with dust shields, the lubricating properties of the grease filled in the bearings may decrease after long-term storage.
3. The storage room should also be protected from vibration and shaking. Bearings that are not stored in the original packaging should be properly preserved. It is strictly forbidden to put bearings and corrosive things together to prevent corrosion and pollution.
4. Large rolling bearings can only be stored flat, and the sides of the inner and outer rings are best supported. If stored upright, permanent deformation may occur due to the relatively thin walls of the inner and outer rings due to the heavy weight of the inner and outer rings and rolling parts.
Reasons for abnormal noise of bearings
There are impurities in the oil;
Insufficient lubrication (oil level too low, improper storage leading to oil or grease leakage through the seal);
The clearance of the bearing is too small or too large (manufacturer's problem);
Impurities such as sand or carbon particles are mixed into the bearing to act as abrasives;
The bearing is mixed with water, acid or paint and other dirt, which will cause corrosion;
The bearing is flattened by the seat hole (the roundness of the seat hole is not good, or the seat hole is twisted and not straight);
The pad iron on the bottom surface of the bearing seat is uneven (causing deformation of the seat hole and even cracks in the bearing seat);
There are sundries in the bearing seat hole (residual chips, dust particles, etc.);
Eccentricity of the sealing ring (hitting adjacent parts and friction);
The bearing is subject to additional load (the bearing is subject to axial tension, or there are two fixed end bearings on one shaft);
The fit between the bearing and the shaft is too loose (the diameter of the shaft is too small or the adapter sleeve is not tightened);
The bearing has too little clearance and is too tight when rotating (adapter sleeve is overtightened).
