The Solutions to Bearing Seal Failure
Premature bearing seal failure can occur for a variety of reasons. Each failure leaves its own special imprint on the bearing. When we meet bearing seal failure, what we can do? You can learn tips to solve the main seven types of bearing seal failure.
Housing Seals Are Too Tight
- Replace the seal with one that has the right tension. Alternatively, machine the shaft to obtain the correct tension for the present spring-type seal.
- Make sure the seals are lubricated properly.
- Check seal lips for wear.
- Felt seals should be soaked in hot oil prior to installation.
Other Components Foul the Bearing Seals
- Check components adjacent to the seals:
- abutment heights
- possibility to accommodate axial displacement if shaft elongation occurs
Multiple Seals in a Bearing (Housing) Arrangement
- If multiple contact seals are used to help keep contaminants out, friction and heat will increase.
- Before adding additional seals to an application, consider the thermal effects on the bearing and lubricant.
- In addition, consider the extra power required to rotate the equipment.
Misalignment of External (housing) Seals
Considerations during assembly:
- Any misalignment of the shaft relative to the housing or the housing seal can cause a non-contact or gap type seal to rub. This condition can elevate temperatures, increase noise levels and accelerate wear during the initial running-in period. It also compromises sealing integrity.
- Check the alignment and correct accordingly.
- If misalignment cannot be avoided, there might be a need to increase the clearance or gaps between the external seals.
Operating Speed Too High for Contact Seals in The Bearing
- Seal lips have a limiting speed. If operating speeds exceed these limits, seal lip damage and grease leakage will result.
- If the operating speed has been increased or if a bearing with a different seal is used, check that the bearing seal can accommodate the speed.
- Contact seals will generate more heat than low-friction seals, shields or open bearings.
Seals Not Properly Lubricated
- Dry running contact seals can add significant amounts of heat to the system.
Action during assembly:
- Make sure that seals are properly lubricated at start-up of new or rebuilt equipment. (Felt seals should be soaked in hot oil, prior to installation.)
Actions during operation:
- Normally the lubricant in the housing will get thrown outward towards the seals and automatically lubricate them.
- Properly lubricated seals will run cooler and will create an effective seal since any gaps between the contacts will be filled with a lubricant barrier.
- Proper lubrication will also reduce premature seal wear.
- Check seals for wear or damage.
Seals Oriented in the Wrong Direction and Not Allowing Grease Purge
Consideration during assembly:
- Depending on the application, contact seals may need to be oriented in a specific direction to either allow the lubricant to purge or to prevent oil leakage.
- Check the application drawings or contact the equipment manufacturer to determine the proper orientation of the seals for the equipment.
Consideration during operation:
- Seal lips that face outward will usually allow purging of excess lubricant and prevent the ingress of contaminants.
- Seals must be oriented correctly to keep grease in and contaminants out of the bearing.