3. Fault and solution of ball bearing S6000RS - clearance problem

Overview of internal clearance of bearing 6000-2RS:
The standard clearance codes include C0 (default), C2 (minimum), C3 (standard), and C4/C5 (larger), which need to be selected according to the operating conditions. The interference fit during installation will reduce the clearance

Solution:
1. Check the packaging to ensure that the internal clearance of the new bearing 6000RS or bearing 6000ZZ meets the original design specifications.

2. If the bearing overheats after replacement, or if the application requires a larger clearance, please contact the supplier of bearing 6000RS to understand the impact of increasing clearance on the equipment and bearings.

3. Check all dimensions, as component wear can affect bearing clearance.

Precautions during redesign or remanufacturing process:
1. In some cases, the materials of the shaft and bearing seat can be changed, such as using stainless steel to comply with food industry regulations, or using aluminum bearing seats to reduce equipment weight.
2. When the thermal expansion coefficient of the shaft material is higher than that of the bearing steel, the radial clearance will further decrease. Therefore, for specific stainless steel materials (not 300 series), slightly loose shaft fittings or bearings with larger radial clearances are required, such as CN to C3 and C3 to C4.
3. If the thermal expansion coefficient of the bearing seat material (such as aluminum) is higher than that of the bearing steel, a slightly tighter fit is required to prevent the outer ring from rotating inside the bearing seat.

Solution:
In both cases, it may be necessary to calculate the impact of the new shaft or bearing seat material on the internal clearance of the bearing and replace the bearing clearance accordingly.

Precautions during the design phase:
Due to design reasons, the inner ring temperature in bearing configurations is usually higher than the outer ring temperature. For example, the shaft in the motor is very hot, causing the inner ring to expand while the outer ring is located inside the motor housing. Due to the large surface area of the shell, it is conducive to heat dissipation, and the temperature difference between the inner and outer rings of the bearing is relatively large.

Precautions during operation:
The large temperature difference between the shaft and the bearing seat can reduce the internal clearance of the bearing, which may lead to a small working clearance or even pre tightening, resulting in an increase in working temperature.

Solution:
1. Check the temperature of the shaft and bearing seat of the nearest bearing.

2. If possible, choose bearings with larger internal clearances to avoid pre tightening, such as CN to C3, C3 to C4, etc.

Precautions during the design phase:
1. The interference fit between the inner ring of bearing 6000-2RS and the bearing journal will cause the inner ring to expand and reduce the internal clearance of the bearing.

2. If the fit is too tight, it may cause the working clearance in the bearing to be too small, and even lead to pre tightening, resulting in overheating of the bearing during operation.

Solution:
1. Check if the internal clearance of the installed bearing 6000RS is correct.
2. If the shaft is new or refurbished, carefully check the size and shape accuracy of the shaft neck.
3. Before taking corrective measures, check the size of the bearing seat hole.
4. If all dimensions meet the specifications, bearings with larger internal clearance may be required.
5. Please note that interference fit on the shaft and in the bearing seat may result in insufficient working clearance.

Factors to consider during design:
1. An interference fit may be required between the outer ring and the bearing seat of the 6000ZZ bearing, but this fit can cause compression of the outer ring and reduce the internal clearance of the bearing.

2. If the fit is too tight, it may cause the working clearance of the bearing to be too small, and even generate preload, which can lead to an increase in the working temperature of the bearing.

Solution:
1. Check if the internal clearance of the bearing is correct

2. For new or refurbished bearing seats, carefully inspect the bearing seat holes to ensure that their size and shape meet the relevant accuracy requirements. Grind the bearing seat again to achieve the appropriate fit. If re grinding is not possible, use bearings with larger internal clearance

3. Pay attention to the interference fit between the bearing and the shaft or bearing seat, which may cause the working clearance of the bearing to be too small

The above is an analysis of several faults caused by clearance in deep groove ball bearings. We have nearly 30 years of rich experience in the production of bearing products. For more bearing use cases, please contact us.