Application of low noise bearings
the essential noise of bearings is the noise that will still occur in bearings manufactured with modern processing technology. The flexible packaging of bearings based on plastic film plays an important role in all kinds of packaging products. The essential noise can be divided into three kinds: raceway sound, impact sound of rolling body and rolling sound, which are described as follows:
(1) raceway sound of bearing and its control method
raceway sound is a kind of slippery and continuous sound produced by the rolling body rolling on the raceway surface when bearing 2 and the error solution are running, and it is a unique basic sound that all rolling bearings will produce. General bearing sound is the sound of raceway plus other sounds
the raceway sound of ball bearing is irregular, and the frequency can sometimes reach more than 1000% and more than 1000Hz. Its dominant frequency does not change with the speed, but its total sound pressure level increases with the speed
for bearings with loud raceway sound, the sound pressure level of raceway sound decreases with the increase of viscosity; For bearings with low raceway sound, the sound pressure level changes from decrease to increase when the viscosity increases to more than 20mm2/s
the greater 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 sound will increase sharply with the reduction of radial clearance
the methods to control the raceway sound are: select low-noise bearings, that is, bearings with small waviness, and carefully select the service conditions. The noise of the whole machine is often affected by the sound of the raceway. Reducing the sound of the raceway can reduce the noise of the whole machine
(2) impact sound of rolling element and its control method
when a larger type of ball bearing or cylindrical roller bearing operates at low speed under pure radial load, due to the small centrifugal force of the rolling element, the rolling element in the non load area will impact the cage or raceway and make noise. But as the speed increases, the sound will disappear
the control methods for the impact sound of rolling elements are: appropriately reduce the radial clearance, and use the bearing of cage with reasonable structure and flexible material
(3) bearing rolling sound and its control method
rolling sound is a harsh metal friction sound that can occur in cylindrical roller bearings on all occasions. It mostly occurs in grease lubricated larger models of bearings, and it is more likely to occur in greases with degraded base oil performance, which rarely occurs in oil lubrication. In addition, it is easy to occur in winter. When bearing pure radial load, it is easy to occur in occasions with large radial clearance, and it is easy to occur within a specific speed range with different models, which will occur continuously and intermittently. Adopting special processing methods for the outer ring raceway can prevent the occurrence of rolling sound. If necessary, this kind of bearing can be selected, or the radial die temperature of the bearing can be appropriately reduced. The clearance of 50 (6) 0 degrees should be taken, and the lubricating grease with excellent performance should be used to improve the rigidity of the parts matching the bearing. (end)
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