Bearing noise is a problem often encountered in the process of motor manufacturing, testing and use. Simply talking about the bearing problem is a very unscientific approach. The problem should be analyzed and solved from the perspective of cooperation in accordance with the principle of correlation.

The rolling bearing itself usually does not generate noise. What is considered “bearing noise” is actually the sound made when the structure around the bearing vibrates directly or indirectly. Therefore, noise problems should usually be considered and resolved in terms of vibration problems involving the entire bearing application. Vibration and noise are often accompanied by.

For a pair of things, the root cause of noise can be attributed to vibration, so the solution to the noise problem should start with reducing vibration.

Bearing vibration can basically be attributed to factors such as changes in the number of rolling elements, matching accuracy, partial damage and pollution during load. The impact of these factors should be reduced as much as possible through the reasonable configuration of the bearing. The following is some experience accumulated in the application to share with you, as a reference and reference in the design of the bearing system.

Exciting force factors caused by changes in the number of loaded rolling elements

When the radial load acts on the bearing, the number of rolling elements bearing the load will change slightly during the rotation, which will cause the bearing to have a slight displacement in the direction of the load. The resulting vibration is unavoidable, but it can be passed in Axial preload is applied to all rolling elements to reduce vibration (not applicable to cylindrical roller bearings).

Accuracy factors of mating parts

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

Local damage factor

If the bearing is improperly handled or installed incorrectly, it may cause partial damage to the raceway and rolling elements. When the damaged bearing component has rolling contact with other components, 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 elements.

Pollution factor

Bearings work under contaminated conditions, and it is easy for impurities and particles to enter. When these pollutant particles are crushed by the rolling elements, they will vibrate. The vibration level caused by the different components in the impurities, the number and size of the particles will be different, and there is no fixed pattern in the frequency. But it may also produce annoying noise.

Influence of bearings on vibration characteristics

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

●Reduce the excitation force that causes vibration in the application

●Increase the damping of the components that cause vibration to reduce resonance

●Change the rigidity of the structure to change the critical frequency.

From actual experience, it is found that solving the bearing system problem is actually a linkage activity between the bearing manufacturer and the user manufacturer. After repeated running-in and improvement, the problem can be solved better. Therefore, in the solution of the bearing system problem, we More advocates for cooperation and mutual benefit between the two parties.