A detailed analysis is conducted on actual fault cases such as peeling and damage to the rolling element and inner and outer ring raceways of the self-aligning roller bearings of a 1.5MW wind turbine at a certain wind farm station.

1、 Wear of bearing raceway

      Long-term uneven stress can lead to cracks in the track and local detachment of flake-like metal fragments. Failure to handle it in a timely manner can also exacerbate wear on the track or may cause ring breakage, leading to spindle system rear running faults and serious economic losses.

Fixed end bearing outer ring raceway failure

Fixed end bearing inner ring raceway failure

2、 Surface peeling of bearing outer ring       During the rotation of the bearing, it is at the fatigue limit for a long time, and small cracks will appear in the stress area. The cracks will gradually form peeling pits, leading to large-scale peeling of the bearing surface, causing the spindle to move backward, and abnormal vibration and noise of the unit.

3、 Damaged bearing cage

       Due to the rough surface of the rolling element, friction is generated when in contact with the retainer, forming a large amount of filamentous chips, which exacerbates the wear of the retainer and may even cause a fracture, posing a potential threat to the stable operation of the generator set.

4、 Bearing rollers

      The scratch characteristics of the rear rolling element of the self-aligning roller bearing are manifested as circular grooves on the contact surface. Contact fatigue peeling occurs on the surface of rollers, often accompanied by fatigue cracks. The peeling surface gradually expands and extends towards deeper layers, forming deep peeling.

Schematic diagram of rolling element failure

       In summary, for abnormal operation of spindle bearings, methods such as cleaning the lubricating grease in the bearing chamber and shortening the oil injection cycle can be used to slow down the deterioration trend of spindle bearings. In this case, the bearing raceway has worn out to the point of failure, and the unit is still in service, so the only solution is to replace the main shaft system to solve the problem. Lifting large components down the tower not only directly leads to a loss of production efficiency in the wind farm, but also brings about high-risk lifting operations. Therefore, timely and effective technical intervention to extend the service life of fixed end bearings is particularly important in the wind power aftermarket.