Industry Knowledge

What are the reasons for excessive bearing noise?

After normal installation, rolling bearings sometimes have a phenomenon of excessive noise during operation. There are many reasons for the increase in bearing noise, which can be eliminated one by one according to the following reasons.

Ⅰ. Metal-to-metal contact

1. Insufficient lubricant (not enough lubricating oil or grease is added);

2. The oil film is too thin and does not adapt to the working conditions (check the performance of the lubricant)

3. The rolling element slides (slips), check the minimum load or clearance value of the bearing;

Ⅱ. Contamination

1. Solid contaminants enter and are crushed, causing dents on the raceway or rolling element. Check the seals and ensure clean installation and use.

2. Solid particles left in the bearing seat during the manufacturing process or previous bearing failure. Before installing a new bearing, clean the shaft, bearing seat and related parts, and remove burrs, etc.;

3. Liquid contaminants reduce the viscosity of the lubricant. Check the bearing seat seals to ensure that they can effectively prevent liquid contaminants from entering. You can also consider using sealed bearings.

Ⅲ. Too loose fit

1. The inner ring creeps (rotates) on the shaft. Surface metal treatment of the journal and grinding to the appropriate size.

2. The outer ring creeps (rotates) in the bearing seat. Surface metal treatment of the bearing seat hole and grinding to the appropriate size.

3. The bearing locking nut on the shaft or bearing sleeve is loose. After installing the bearing, tighten the nut to put the inner ring in the proper position (proper internal clearance of the bearing).

4. The bearing and the mating parts are not clamped. Make sure that the locking device accurately positions the two bearings against the shaft shoulder or spacer.

5. The radial/axial clearance of the bearing is too large. Use springs or wave washers to provide appropriate axial loads to keep the rolling elements under load (mainly used in ball bearings).

IV. Surface damage

1. Ineffective lubrication leads to abrasive wear. Check the amount of lubricant added and the correct installation direction of the seal. When the direction is correct, excess grease can be discharged while preventing contaminants from entering. At the same time, ensure that the relubrication interval is not too short, check the working viscosity of the lubricant and the lubrication system, etc.

2. Adhesive wear caused by rolling element sliding. In order to achieve good bearing operation and avoid tailing, all ball bearings and roller bearings must withstand a certain minimum load.

V. Friction

1. Improper installation of bearing seat seals. If misalignment cannot be avoided, the clearance or gap between the external seals may need to be increased.

2. Improper installation of adapter sleeves and withdrawal sleeves. After installation, confirm that the lock nut is tightened (such as using a locking washer tongue clamp).

3. Improper clamping of the spacer sleeve. Make sure that the locking device accurately positions the two bearings against the shaft shoulder or spacer.

4. The locking washer tongue is bent. Some locking washers have bent tongues, which will affect the cage or seal,causing noise, accelerated wear and damage. Be sure to replace the qualified locking washers.