vibration on bearing cage 1

[baris23]

? try to analyse the vibration effects on bearing cage,
under the vibration the cage fails after some time,(i think because of fatique=
does anybody recomend me a source to understand what happens on yhe cage?
and which fea prog. do you recomen to analyse this?

 

[CESSNA1]

BARIS23:

Did you have a metallurgical analysis performed to identify the material and cause of failure? Typically vibration causes brinnelling of the rollers and races as experienced by Chevrolet in shipping Vegas in the late 70's. Do you have additional informatin such as conditions, time, environment, etc?

The cage just goes around with the rolling elements and keeps them separated. Ir sees virtually no load.

Regards

Dave

 

[rob768]

When axially load, the cage may fail

 

[baris23]

Thank you CESSNA1,
i think the vibration on the cage depends on the angular velocity..
and if i give an angular acceleration to the or approximately 160 G force occurs on the ball..(so the cage)
i think the failure of the cage depends on vibrational fatique..

what is your opinion?

Regards

 

[EnglishMuffin]

Are you talking balls or rollers here, and what is the cage made of ? One thing that can cause cage failure in a ball bearing, particularly with phenolic cages, is excessive ball excursion (ie tangiential oscillatory ball motion that exceeds the clearance between rolling element and cage). Ball excursion can be computed with a computer program if the internal bearing geometry and loading conditions are known. Excursion under purely axial load is theoretically zero.

 

[baris23]

Thanks Englishmuffin
the cage made of steel and it fails from the rivet holes or the radiuses where the ball pocket starts..
what kind of computer prog. did you mention?
is there a spesific program about these problem?

 

[EnglishMuffin]

Well, most programs are proprietory (RHP, SKF, FAG etc) - the first thing to try is a bearing manufacturer. Some of them have developed very sophisticated cage analysis software. I used to use a program called ABODE written by a non-bearing manufacturer - that would calculate excursion, but the web site seems to have disappeared and that guy may have gone out of business. You could also try Poplawski Associates, but all of these special programs are very expensive to buy because they are so specialized and they don't sell very many. Poplawski has a lot of experience with bearing consulting, so he may be able to help you with your problem directly.

http://www.bearingspecialists.com

 

[Tmoose]

If the lubrication is marginal the cage suffers first.
Excessive speed for the bearing can do that, as well as outright lube problems.

If the balls are trying hard to change lanes the cage suffers badly. Excessive thrust loads or bad bearing seat geometry can do that. Mechanically it has to be right. I'd say more bearing (and vibration) problems are solved with a dial indicator than FEA.

//ahrinternational.com/PDF_catalogues/FAG/FAG_roller_bearing_damage_analysis.pdf

 

[EnglishMuffin]

I should probably clarify that the type of computer programs I am talking about do not necessarily have much to do with FEA, at least not as normally understood, although they do arrive at a result by solving a large number of simultaneous non-linear equations - along the lines first pioneered by Bert Jones in the fifties. They enable one to input such things as internal bearing geometry, which you have to know and can be hard to obtain, and external geometry, including misalignment. Poplawski has also developed a bearing program which interacts with an FEA code (ANSYS) for thermal/structural analysis for the main mounting structure, but in terms of classic FEA, that's about it at least as far as his programs go.