The vibration of rolling bearings is the source of bearing noise. Different bearing noises come from different types of bearing vibration. Like bearing vibration, the generation mechanism of bearing noise is also very complex. According to the characteristics of bearing noise, bearing noise can be divided into the following forms:
The noise generated by the structure and size of the bearing is the basic noise, such as the elastic deformation of the bearing, the rolling body, the clearance, the cage and so on.
The noise caused by the bearing surface effect: such as the inner and outer ring of the bearing, the noise caused by the roundness, corrugancy, roughness and defects of the steel ball working surface. A large number of experimental studies show that the surface quality of outer ring, inner ring and steel ball of deep groove ball bearing has a ratio of 1:3:10 influence on the bearing noise, and the surface quality of steel ball has the greatest influence on the noise of deep groove ball bearing.
Noise generated by friction and lubrication: friction and lubrication have a great impact on the noise of rolling bearings, small friction, good lubrication state, the noise generated by bearings is small.
Noise caused by working conditions: the load, speed and installation state of bearings directly affect the production of bearing noise. The higher the speed of bearings and the greater the load, the greater the noise produced by bearings is. In addition, relevant studies show that 50% of bearing noise is caused by poor installation.
The cause of bearing noise
Excitation caused by the change of the number of loaded rolling bodies: When a radial load is loaded on a bearing, the number of rolling bodies carrying the load will change slightly in operation, resulting in the deviation of the load direction. The resulting vibration is inevitable, but can be alleviated by axial preloading on all rollers (not applicable to cylindrical roller bearings).
Local damage: Due to operation or installation errors, a small part of the bearing raceway and rolling body may be damaged. During operation, the damaged bearing parts will produce a specific vibration frequency; Vibration frequency analysis can identify damaged bearing parts. This principle has been applied in condition monitoring equipment to monitor the condition of bearing damage.
Accuracy of related components: In the case of close coordination between the inner and outer ring of the bearing and the bearing seat or the transmission shaft, the outer and outer ring of the bearing may be mismatched with the shape of the adjacent parts and deformed. If deformation occurs, vibration may occur during operation.
Contaminants: If the equipment is operated in a polluted environment, impurities may enter the bearing and be rolled by the rolling body. The degree of vibration produced depends on the number, size and composition of the crushed impurity particles. This does not produce the typical frequency pattern, but a disturbing noise can be heard.
Other: rolling bearing noise causes more complex, one is the bearing inner and outer ring with surface wear. Because of this wear, the mating relationship between the bearing and the shell, the bearing and the shaft is destroyed, resulting in the axis deviating from the correct position. The shaft produces abnormal noise when moving at high speed. When the bearing is tired, its surface metal spalling will also increase the radial clearance of the bearing and produce abnormal noise. In addition, insufficient bearing lubrication, the formation of dry friction, and bearing crushing will produce abnormal sound. Bearing wear, loose and damaged cage, will also produce abnormal noise.
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