1. fatigue spalling

The inner and outer raceways of the rolling bearing and the surface of the rolling element bear both load and relative rolling. Due to the action of alternating load, cracks first form at a certain depth below the surface (at the maximum shear stress), then extend to the contact surface to cause spalling pits on the surface, and finally develop into large spalling. This phenomenon is fatigue spalling. Fatigue spalling will increase the impact load, vibration and noise during operation.

2. wear

Due to the invasion of dust and foreign matters, the relative movement of the raceway and the rolling element will cause surface wear, and poor lubrication will also aggravate the wear. As a result, the bearing clearance will increase, the surface roughness will increase, and the bearing operation accuracy will be reduced. Therefore, the motion accuracy of the machine will be reduced, and the vibration and noise will also increase. For precision mechanical bearings, it is often the amount of wear that limits the life of the bearings.

3. plastic deformation

When the bearing is subjected to excessive impact load or static load, or additional load caused by thermal deformation, or foreign matters with high hardness invade, dents or scratches will be formed on the raceway surface. This will cause severe vibration and noise during the operation of the bearing. And once there is an indentation, the impact load caused by the indentation will further cause the spalling of the nearby surface.

4. corrosion

Corrosion is one of the most serious problems of rolling bearings. High precision bearings may lose accuracy due to surface corrosion and cannot continue to work. Direct invasion of water, acid and alkaline substances will cause bearing corrosion. When the bearing stops working, the bearing temperature drops to the dew point, and the moisture in the air condenses into water drops attached to the bearing surface, which will also cause corrosion. In addition, when there is current passing through the bearing, the current may pass through the contact point between the raceway and the rolling element, and a very thin oil film may cause electric spark and produce electric corrosion, forming a washboard like unevenness on the surface.

5. fracture

Excessive load may cause bearing parts to break. Grinding, heat treatment and improper assembly will cause residual stress. Excessive thermal stress during operation will also cause fracture of bearing parts. In addition, improper assembly method and process may also cause block falling off at the retaining edge of bearing ring and the chamfer of roller.

6. gluing

When working under poor lubrication, high speed and heavy load, the bearing parts can reach very high temperature in a very short time due to friction heating, resulting in surface burns and gluing. The so-called gluing refers to the phenomenon that the metal on the surface of one part adheres to the surface of another part.

7. damaged cage

Improper assembly or use may cause deformation of the cage, increase the friction between it and the rolling elements, or even make some rolling elements stuck and unable to roll, and may also cause friction between the cage and the inner and outer rings. This damage will further aggravate vibration, noise and heat, resulting in bearing damage.