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Centrifugal force on bearings

Centrifugal force on bearings

Centrifugal force on bearings

We were working on an application regarding the skidding of rollers.  The bearing is a NU248.  I wanted to know the exact speed needed so that the rollers were just lifting off the raceway.  IE having the centrifugal force equal to the force of gravity....

How should I go about doing this?  Should I ignore the inner and outer rings and cage and concentrate on the rollers being the bodies that are rotating around the center of the shaft?  Should I use the inner ring as it may also be expanding as the centrifugal force increases?  I have worked with some simplified formulas, but the question is always, which weight do I use?  Thanks.


RE: Centrifugal force on bearings

Have you contacted the Engineers at the bearing manufacturer?

They have probably done tests like this.  Off hand I would say you cannot ignore anything.  Including the radial and axial forces applied to the bearing in addition to gravity.

Are you examining the bearing itself without any other applied load?  If so what would be the point?  You may obtain the speed you are looking for, but when you apply a load to the bearing that speed becomes invalid.

RE: Centrifugal force on bearings

You better give this one to your bearing supplier. All bearings have a max RPM for both oil and grease. IF this is a thrust application, there needs to be a certain preload force applied to prevent skidding the rollers - the same holds true for radial bearings.

I've been working w/ engineers at Timken, SKF, NSK etc and they have more answers than you have questions.

Keep the wheels on the ground

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