There are many reasons for the failure of cylindrical roller bearings. In addition to normal bearing fatigue peeling, factors such as failed sealing, too small bearing clearance caused by tight fitting, or poor lubrication can leave special traces and forms of failure. Therefore, checking for bearing failure often reveals the cause of bearing failure, and corresponding measures can be taken in a timely manner to prevent it.
Generally speaking, one-third of the failure of bearings is due to the fact that they have reached the fatigue peeling period, which is considered normal failure; 1/3 of the bearings failed prematurely due to poor lubrication, and 1/3 of the bearings failed prematurely due to contamination entering the outer spherical bearings or incorrect installation. Generally speaking, there are seven common symptoms of abnormal bearing operation: bearing overheating, excessive bearing noise, low bearing life, high vibration, failure to meet machine performance requirements, bearing looseness on the shaft, and difficulty in shaft rotation.
The raceway sound of bearings and its control methods. The raceway sound is a smooth and continuous sound produced by the rolling element on the raceway surface when the second type of bearing is running. It is a unique basic sound that occurs in all rolling bearings. The general sound of an outer spherical bearing is the combination of raceway sound and other sounds. The raceway sound of bearings is irregular, with a frequency above 1000Hz. Its main frequency does not change with the speed, but its total sound pressure level increases with the speed. For bearings with high raceway sound, the sound pressure level of raceway sound decreases with increasing viscosity; However, for Class II bearings with low raceway noise, the sound pressure level changes from decreasing to increasing when the viscosity increases to about 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 the raceway sound will sharply increase with the decrease of the radial clearance. The methods for controlling raceway noise include selecting low noise bearings, i.e. bearings with very low ripple, and carefully selecting the usage conditions. Rolling track noise often affects the noise of the entire machine, and reducing rolling track noise can reduce the noise of the entire machine.
The impact sound of rolling elements and its control method. When larger types of bearings or outer spherical bearings operate at low speeds under pure radial load, due to the small centrifugal force of the rolling element, the rolling element in the non load zone will impact the cage or raceway and emit noise. But as the speed increases, this sound will disappear. The control methods for the impact sound of rolling elements include appropriately reducing radial clearance and using Class II bearings with reasonable structures and compliant materials as cages.
Rolling sound of bearings and its control methods Rolling sound is a harsh metal friction sound that can occur in all occasions of bearings, mostly in larger types of bearings lubricated with grease, and is more likely to occur in lubricating greases with degraded base oil performance, which almost does not occur during oil lubrication. In addition, it is more likely to occur in winter, when subjected to pure radial loads, in situations with large radial clearance, and depending on the size of the model, it is prone to occur within a specific speed range, both continuously and intermittently. Adopting special processing methods for the outer ring raceway can prevent the occurrence of rolling noise. If necessary, this type of outer spherical bearing can be selected, or the radial clearance of the bearing can be appropriately reduced, high-performance lubricating grease can be used, and the rigidity of the matching parts with the bearing can be improved.
