bearing malfunction 1

[ghaniad]

HI,
I'm the bearing distributor,we sold the bearing "Axial Spherical Roller Baering 29430E1 FAG" to our client.Now they are complaining that the rollers are comming out from the retainer during the operation.I can't bleave that its happend to the bearing,we checked our stock the same bearings those are in good shape and attached with retainer.
What do you think something happend wrong during the installation?

 

[electricpete]

For starters, I would look at whether minimum load is met.

There are gyroscopic forces as these rollers change their axis (increase with speed). Needs enough load at all times to keep it together.

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(2B)+(2B)' ?

 

[electricpete]

Here is a calculation for minimum load for spherical roller thrust beairngs from SKF:

http://www.skf.com/portal/skf/home/products?maincatalogue=1&lang=en&newlink=1_11_9

If you click on the equation, it will open a calculation dialogue box. Enter the bearing part number, operating oil viscosity, and speed and it will spit out a minimum load requirement.


=====================================
(2B)+(2B)' ?

 

[Tmoose]

Have you sent FAG's engineering department pictures and failed bearings yet? I'd think you'd have a direct line to FAG's engineering department. I sure liked it when I did.

 

[Tmoose]

Rollers escaping the retainer might be the last phase of retainer/cage wear. very Generally speaking cage wear is an indication of inadequate lubrication.

Really need some parts to look at.

 

[ghaniad]

thanx guys for reply,
we are waiting for the pictures of the bearing on site and we'll check out the load too.

 

[geesamand]

Spherical rollers have a couple of failure modes that aren't obvious.

1) For SR's that are under combined load, consider that one set of rollers ends up taking all of the load. The other set of rollers will coast down to a slower non-synchronous speed. If the loading is consistent this tends to not create trouble. However if the load shifts suddenly to radial load only or the axial load is varying, those coasting rollers will accelerate ungracefully and skidding here can eat up the bearing.
2) Check that the endplay settings are suitable. If you artificially constrain the outer races you can prevent the radial load from being shared across both sets of rollers.
3) Some people swear by brass cages. Since SR's depend greatly on the cage to stabilize the rollers, I can see some value here.
4) Low temp startups and other lubrication challenges can eat a grease lubricated SRB in short order. There is typically enough void space in the SRB to allow grease to be pushed aside, and in very cold temps the grease stops entering the roller path and the whole thing heats up and fails. Just another thing to consider.