Brinelling of Bearings

Impact or oscillatory damage; how many of us think about these when we are storing, handling and installing bearings? How often do we consider it during the repair or alignment of machines/equipment with rolling element bearings?

Who has:

  • dropped a bearing (oops!)?

  • impacted an interference fit fitment, such as a coupling hub etc., that is seized onto a shaft (hammer time oops!)?

  • beat a bearing onto a shaft or into a housing?

  • hit the machine with the big hammer to move it (no jacking bolts oops!),

  • let that spare machine sit on the warehouse shelf or in the field for months or even years with no rotation (oops!)?

And the list could go on and on…we’ve all probably been guilty of at least one or more of these infractions at some point. “What’s the big deal anyway?” Well, quite often we talk about bearing failures as if they are simply normal and should be expected. While there are some normal/end of service life/fatigue type failures in the bearing world, the overwhelming majority (95%) are premature and therefore warrant a closer look.

In fact, two very common bearing damage types are responsible for many of these failures and are easily preventable. They can at least be minimized by simply doing “the right things”.

The damage types are True and False Brinelling.

Proper fits eliminate the need for hammers.

Use of bearing heaters is strongly recommended no matter how small the bearing.

Here the vibratory action between the rolling element and the raceway surface creates axial lines. If the bearing remains in that position long enough, it will create hollow spots. Again when placed in service the damaged areas act as stress risers and fatigue failures ensue.

Whenever a bearing fails prematurely, the first question asked should be “what caused it to fail and how can we not have this same failure reoccur?” In the case of Brinelling, it is typically avoidable. At the very least the risk can be minimized greatly.

To prevent True Brinelling:

  • Minimize impacts to bearing or machine during transportation

  • Use precision installation techniques (measure shaft and housing fits precisely)

  • Use correct installation tools

  • Practice handling bearings with care

To prevent False Brinelling:

  • Avoid vibration while bearing/machine is stationary

  • Secure shafts on machines during transport

  • Periodically rotate stored spares

  • Periodically rotate field spares in/out of service

In summary, most Brinelling failures are preventable with just a little extra care and attention. Take the time to observe bearing failures to understand root causes that can be eliminated or at least reduced greatly. Reliable Manufacturing principles ensure that we examine, learn, grow and move forward with confidence.

Good Luck! Please provide us feedback on examples of your success!

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