Bearing noise is a common problem encountered in the process of motor production, manufacturing, testing and use. Simply talking about the problem of bearings is a very unscientific approach. We should analyze and solve the problem from the perspective of coordination according to the principle of association.

Rolling bearings themselves usually do not produce noise. What is considered as "bearing noise" is actually the sound produced when the structure around the bearing directly or indirectly produces vibration. Therefore, the noise problem should usually be considered and solved according to the vibration problem involving the whole bearing application. Vibration and noise are often accompanied by a pair of things, the source of noise can be attributed to vibration, so to solve the problem of noise should start with reducing vibration.

Bearing vibration can be basically attributed to the number of rolling body changes, matching accuracy, local damage and pollution when the load is activated, and the influence of these factors should be reduced as far as possible through the reasonable configuration of bearings. The following Ms. Reference will be some of the application of the accumulation of experience with you to do a share, as a reference for bearing system design.

The excitation force factor caused by the change of the number of loaded rolling body

The effect on the bearing radial load, the load of rolling element in the process of turning number will change slightly, so lead to bearing has a slight displacement along the direction of the load, thus vibrations is unavoidable, but can pass on all roller axial pre-tightening force to reduce the vibration (not applicable to cylindrical roller bearing).

Precision factor of fitting parts

If there is an interference fit between the bearing ring and the bearing seat or shaft, the bearing ring may follow the shape of the connecting parts and deform. If there is a deviation in shape between the two, it may cause vibration during operation. Therefore, the journal and seat holes must be machined to the required tolerance standards.

Local damage factor

If the bearing is improperly handled or installed, it may cause partial damage to the raceway and rolling body. When the damaged bearing part has rolling contact with other parts, the bearing will produce a special vibration frequency. By analyzing these vibration frequencies, it is possible to determine which bearing component is damaged, such as the inner ring, outer ring or rolling body.

Pollution factors

Bearings work under polluted conditions and are easy to allow impurities and particles to enter. When these particles are crushed by a rolling body, they vibrate. Different components, number and size of particles in the impurities cause different levels of vibration, and there is no fixed pattern of frequency. But it can also produce disturbing noise.

Influence of bearing on vibration characteristics

In many applications, the rigidity of the bearing is roughly the same as that of the surrounding structure. Therefore, the vibration of the whole equipment can be reduced by selecting the appropriate bearing (including preload and clearance) and configuration mode. Methods to reduce vibration are:

① Reduce the excitation force caused by vibration in the application

(2) Increase the damping of the component causing the vibration to reduce the resonance

③ Changing the rigidity of the structure to change the critical frequency.