Radial clearance out of tolerance

Cause analysis

1. The value of the ring size sorting is inaccurate due to accidental errors in sorting, measurement system errors, etc.

2. When measuring radial clearance, the steel balls are unevenly divided, the measuring position is inaccurate, and the hand thrust is inconsistent.

3. The bearing parts are not clean enough and contain dirt and dirty oil.

4. The cage is riveted too tightly and deformed, resulting in the center of the steel ball not being distributed on the center circle of rotation of the bearing rolling element.

Solution

1. Find the pattern and correct the sorting size or clearance.

2. Standardize the clearance measurement operation.

3. Demagnetize and clean the bearing again.

4. Replace the cage and standardize the assembly operation.

5. Replace the cage and strengthen the inspection.

Rotational accuracy out of tolerance

Cause analysis

1. During the grinding process of the ring, the parallelism of the center plane of the raceway to the reference end face is out of tolerance.

2. The reference surfaces of the inner and outer raceways are damaged.

3. The surfaces of the inner and outer raceways are damaged or dirty.

4. The diameter variation of the inner and outer raceways is large, and the groove shape is out of tolerance or deformed.

5. When the last steel ball is installed, the outer ring is deformed and the steel ball surface is scratched.

6. There may be mixed balls installed, and the diameter variation of the steel ball batch is too large.

7. The cage is deformed.

8. The thickness variation Ki or Ke of the inner diameter or outer diameter surface of the raceway of a single ring exceeds the tolerance, resulting in Kia or Kea exceeding the tolerance.

9. When using a spindle for measurement, the spindle's rotation accuracy or the center hole is worn, the surface is scratched, there is dirt inside, and the top surface is worn.

Solution:

1. Strictly inspect and prevent such parts from entering the assembly process.

2. Find out the cause of the damage and eliminate it.

3. Eliminate the factors that cause the raceway damage and re-demagnetize and clean.

4. Prevent such parts from entering the assembly process.

5. Adjust equipment parameters and improve assembly technology.

6. Strengthen inspection and standardize operation.

7. Establish specifications to reduce deformation.

8. Strictly inspect and prevent such parts from entering the assembly process.

9. Eliminate various influencing factors and grind the spindle and top.

Dimensional accuracy exceeds tolerance

Cause analysis

1. The previous process missed inspection.

2. The dimensional stability of precision bearing rings is poor.

3. The instrument has large error or incorrect adjustment, and the force applied during measurement is uneven.

4. The temperature difference in the assembly inspection environment is large, and the standard parts and rings are not kept at a constant temperature enough.

5. The standard parts used in grinding and finished product inspection are not suitable.

Solutions

1. Strictly inspect to prevent such incidents from happening.

2. Summarize experience and improve process.

3. Improve detection methods and skills.

4. Ensure constant temperature time and improve working environment.

5. Use calibration standard parts and instruments to standardize detection procedures.

The dust cover and sealing ring are loose or leaking grease seriously

Cause analysis

1. The tooth groove size is too large, and the dust cover or sealing ring cannot be tightened.

2. The dust cover and sealing ring are not processed properly.

3. The grease injected into the bearing may have too low viscosity or other items may be unqualified.

4. Too much grease injected.

Solutions

1. Strengthen inspection and improve tooling.

2. Unqualified parts are prohibited from entering the assembly room.

3. Strengthen inspection and add qualified grease.

4. Add grease according to the specified requirements.