Bearing spalling
Bearing spalling
(OP)
Maintenance man has a double row spherical roller bearing. Inner race bore is 9" The inner race looks to be in good shape but the outer race has heavy spalling about a quarter of the way around it's inner circumference. The cage is 2 pieces and is made of Al. One of the cages has a crack right through in about the middle of where the roller ends touch it. I guess it is called the pocket. My question is would this be too much axial loads? If it is why wouldn't both races have spalling? Thanks Mates.





RE: Bearing spalling
Mike Halloran
Pembroke Pines, FL, USA
RE: Bearing spalling
This is one of my favorites -
http://www.pheltom.pl/katalogi/FAG%20uszkodzenia%2...
Cage damage (wear) is often a result of poor lubrication.
Busted cages can result from misaligned running.
Localized race damage can result from poor bearing housing geometry.
Spalling is can be the natural end-of-life failure. How long was the bearing in service.
RE: Bearing spalling
So if I read that right, the cage was still doing it's job to control the position of the rolling elements. In that case IF we assume the two symptoms are related (not necessarily a good assumption), the spalling may have increased stress on the cage.
Got any pictures. ?
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(2B)+(2B)' ?
RE: Bearing spalling
Yeah, despite what Sam used to say, spherical rollers can self align to compensate nicely for a degree or so of static misalignment, like results when the bearing pedestals are of different heights (as they always are) or if a uniform shaft carrying a fat center hung impeller bows to a consistent sway backed state in operation.
http://www.skf.com/binary/30-143712/1011%25200024%...
or page 4 here -
http://www.skf.com/binary/21-148465/6100_EN.pdf
But sometimes the shaft abutment shoulders are not machined square on the shaft, or the tapered adapter is jammed kind of like this -
https://cdn.flii.by/image/ok886sbrd64.jpg,
That creates dynamic misalignment as is discussed a little on page 35 in the SKF link.
http://www.skf.com/binary/21-148465/6100_EN.pdf
Then the inner race moves back and forth axially like a swash plate, and the rollers have to weave back and forth across the outer race which involves some sliding, which the cages try to control.
Also page 125 (127?) here -
http://www.skf.com/binary/tcm:12-114679/140-710%20...
Until the OP posts a useful amount of background info the discussion will remain mighty ethereal.
Maybe next time.
RE: Bearing spalling
I liked your photo of jammed tapered adapter although it may have been a little over my head.
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(2B)+(2B)' ?
RE: Bearing spalling
RE: Bearing spalling
Careful assembly of the history, etc , plus confirmation of shaft and housing geometry, and thorough evaluation of the bearing just as it was removed including wear debris and old lubrication , and evaluation of operating conditions and resulting loading can often whittle away nearly all the variables.
Anything less is, well, less.
If the bearing did not attain a reasonable life, the root cause really needs to be sought out if better performance is desired.
If someone is just curious, but not so curious as to make the effort to root out the facts, then that's OK too.