The nature of bearing noise

For the use of bearings, noise is very common. Even the low noise bearing in the bearing has the same situation. So why is there noise?
(1) Raceway sound of bearing and its control method
Raceway sound is a kind of smooth and continuous sound produced by the rolling element rolling on the raceway surface when the shaft is rotating. It is a unique basic sound of all rolling bearings. The general bearing sound is raceway sound plus other sounds. The raceway sound of ball bearing is irregular, and its frequency is above 1000Hz. Its main frequency does not change with the speed, but its total sound pressure level increases with the speed increasing. The results show that the sound pressure level of raceway noise decreases with the increase of viscosity; However, the sound pressure level of the bearing with small raceway noise increases from decreasing to increasing when the viscosity increases to more than 20mm2 / s. The higher the rigidity of the bearing seat, the lower the total sound pressure level of the raceway sound. If the radial clearance is too small, the total sound pressure level and dominant frequency of raceway will increase sharply with the decrease of radial clearance. The methods to control raceway noise are: selecting low noise bearing, that is, bearing with small waviness, and carefully selecting service conditions. Raceway noise often affects the noise of the whole machine. Reducing raceway noise can reduce the noise of the whole machine.
(2) Impact sound of rolling element and its control method
When the larger type of ball bearing or cylindrical roller bearing runs at low speed under pure radial load, because the centrifugal force of the rolling element is small, the rolling element in the non load area will impact the cage or raceway and make noise. But as the speed increases, the sound disappears. The methods to control the impact sound of rolling element are: reducing the radial clearance properly, using the cage bearing with reasonable structure and flexible material.
(3) Rolling noise of bearing and its control method
Rolling noise is a kind of harsh metal friction noise that can occur in all occasions of cylindrical roller bearings. It mostly occurs in the larger type of grease lubricated bearings, and it is more likely to occur in the grease with poor base oil performance, and it hardly occurs in the oil lubrication. In addition, it is easy to occur in winter, when bearing pure radial load, it is easy to occur in the situation of large radial clearance, and it is easy to occur in a specific speed range with different models, which will occur continuously and intermittently. If necessary, this kind of bearing can be selected, or the radial clearance of the bearing can be appropriately reduced, the lubricating grease with excellent performance can be used, and the rigidity of the parts matched with the bearing can be improved.