Bearing rings and balls are not perfectly round. These imperfections can cause unwanted vibration, potentially damaging the bearing during its lifespan. Rough or damaged balls or raceways, contamination inside the bearing, inadequate lubrication, incorrect shaft or housing tolerances can all contribute to a bearing’s vibration and in turn, can lead to excess noise.
When searching for a bearing with low noise, a good quality bearing will have excellent surface finish on balls and raceways. During the manufacturing process, the roundness of the balls and bearing rings will be very closely controlled.
Bearing fitting is another important factor to consider. Poor fitting practices can cause dents in the bearing raceways which will greatly increase vibration. Similarly, contaminants in the bearings can cause unwanted vibration. If the bearing is not used in a very clean environment, proper seals should be considered.