What are the maintenance methods for adjusting-circle roller bearings after they become worn?

After the adjustment roller bearing wears out, the repair method needs to be determined based on the degree of wear, the structure of the bearing, and the requirements of the equipment operation. The following are common repair methods and precautions:
1. Repair for mild wear
1. Surface polishing and cleaning
Applicable scenarios: Minor scratches, rust, or rough wear appear on the bearing raceway and roller surfaces, but the base material has not been damaged. Operation steps:
Clean the bearings thoroughly with kerosene or a dedicated cleaning agent to remove oil stains and impurities.
Use fine sandpaper (above 800 mesh) or grinding paste to gently sand the worn surfaces, polishing them evenly in a circular direction to avoid damaging the original geometric accuracy.
Clean and dry again, check the surface smoothness, and ensure there are no obvious scratches remaining.
Notes: Do not over-grind to avoid changing the bearing fit dimensions; only applicable to non-critical parts or low-speed, light-load equipment.
2. Welding repair (use with caution)
Applicable scenarios: Local wear is deep (such as local peeling of the raceway), but the overall structure of the bearing is not damaged. Operation steps:
Pre-treat the worn area to remove oil stains and oxide layers.
Use welding rods or wires that match the bearing material (such as high-carbon chromium bearing steel GCr15) for repair welding. Control the welding temperature to avoid bearing annealing.
After welding, perform annealing treatment (to relieve stress) and grinding processing to restore the dimensional accuracy and surface roughness. Notes:
Re-welding may cause deformation of the bearing or a decline in material performance, and is only suitable for non-precision equipment or temporary emergency repairs.
After the repair, the bearing clearance and rotational flexibility need to be re-tested.
II. Maintenance methods for moderate wear
1. Replace local parts
Applicable scenarios: The inner ring, outer ring, or rollers of the bearing are severely worn, while other components are intact. Operation steps:
Disassemble the bearing, inspect the wear condition of each component, and determine the parts that need to be replaced (such as individual rollers, inner ring or outer ring).
Purchase original factory parts or high-precision substitutes of the same model as the original bearing to ensure consistency in size, tolerance and material.
Reassemble the bearing, adjust the clearance to the standard range, and check the smoothness of rotation. Notes:
The inner ring, outer ring and rollers of the self-aligning roller bearing need to match the tolerance. Non-original accessories may cause running noise or shortened lifespan.
During assembly, special tools should be used to avoid damaging the bearings by knocking.
2. Electroplating / Brush Plating Repair
Applicable scenarios: The mating surfaces of the bearing (such as the inner ring and the shaft neck, the outer ring and the seat hole) are worn and the clearance exceeds the standard, but the overall structure is intact. Operation steps:
Electrochemical electroplating (such as hard chrome plating) or brush plating is carried out on the worn areas to increase the thickness of the surface layer and restore the mating dimensions.
After plating, grinding processing is carried out to ensure that the dimensional accuracy (such as the inner diameter of the inner ring, the outer diameter of the outer ring tolerance) meets the requirements. Notes:
The coating thickness is limited (usually 0.05 - 0.1mm), and is only suitable for mild to moderate wear;
Ensure a firm bond between the coating and the substrate to avoid peeling off during use.
III. Handling of Severe Wear or Structural Failure
1. Replace the bearing as a whole Applicable scenarios:
Wear causes excessive bearing clearance, abnormal rotation sounds or excessive vibration;
Large-scale peeling, cracks, fractures or other structural damages occur on the raceway or rollers;
The repair cost exceeds the price of a new bearing or the reliability cannot be guaranteed after repair.
Key operation points:
Select bearings that are exactly the same as the original model, paying attention to the precision grade (such as P0, P6, P5, etc.) and clearance group (such as C3, C4).
Install the bearings correctly to ensure the matching interference, lubrication and sealing meet the equipment requirements, and avoid premature failure of the new bearings due to improper installation.
2. Analyze the failure cause and improve
After replacing the bearings, it is necessary to trace the root cause of wear to avoid repeated failures:
Lubrication issue: Check the type of lubricating grease, the amount added and the replacement cycle to avoid lack of oil or deteriorated grease;
Installation issue: Confirm whether the coaxiality and fit tolerance meet the requirements to avoid uneven loading or insufficient interference;
Working condition issue: Evaluate whether the load, speed and temperature exceed the rated parameters of the bearing, and upgrade the bearing model (such as increasing the bearing capacity or high-temperature resistance grade) if necessary.
Four. Detection and acceptance after repair
Dimensional inspection: Use tools such as micrometers and dial indicators to measure the inner diameter, outer diameter, width and clearance of the bearing to ensure compliance with standards.
Rotation test: Manually rotate the bearing to check if it is flexible, if there is any jamming or abnormal noise.
Vibration detection: Run the equipment after installation, use a vibration detector to measure the vibration amplitude and frequency to determine if there is imbalance or misalignment problems.
Temperature monitoring: Regularly check the bearing temperature during the initial operation to ensure that the temperature rise is within the normal range (generally not exceeding the ambient temperature by 40°C).
Five. Precautions and preventive measures
Avoid blind repair: For high-precision equipment (such as machine tools, motors), after wear, repair is difficult, and priority should be given to replacing new bearings.
Record maintenance files: Record the bearing model, cause of wear, repair method and subsequent operation status to provide reference for equipment maintenance.
Regular maintenance and upkeep:
Add lubricating grease according to the cycle to avoid contamination and aging;
Regularly check the operating temperature, vibration and noise of the bearing to detect early signs of wear in time. 
By conducting a scientific assessment of the wear degree and choosing the appropriate repair method, the service life of the bearings can be effectively prolonged or the equipment downtime costs can be reduced. For important equipment, it is recommended that the repair be carried out by professional bearing maintenance institutions or original factory technicians to ensure reliability.