Any particular make of bearing?

SKF, FAG? ■

Greetings Sganesh,

Do you mean a "Ringfedder" type locking ring?

They have a specific bolt number sequence for tightening etc.

What is the job for these bearings-meaning what are the bearings used for.

What is the shaft speed-RPM

How big are the bearings-4-15/16-5-15/16 or larger? is it a bearing with a split case to allow the bearing to nest in the two halves? Does the bearing have two halves?

Is the bearing an oiled bearing or does it use grease for lubrication?

One other thought-are you using taper locks to make up for smaller shafts on the head and tail pulleys?

Anyway the inner bore of the bearing should not have a tapered bore period unless something has drastically changed in 9 years.

Do you mean a "taper lock" for a bearing to anchor a tail pulley or head pulley on a shaft?

I have only seen taper locks for head and tail pulleys and "Ringfedder" locking rings used to secure a centrifugal flywheel weight on a gearbox for a primary breaker to secure it in use in my previous occupation.

The locking ring is designed to squeeze both the shaft and the outer diameter with equal force to hold everything in place using a large number of allen bolts torqued and anchored with "loctite" and the bolt heads are wired also for example.

If the tightening is not done properly the anchoring of the object wll be lopsided-more anchoring on one side than the other and the other side will begin to wear and wobble and the bolts may break.

If you are using "taper locks" for for undersize shafts that is not good but I do not know what your bearings are used for etc.

A bearing has either a press fit-tight or a locking fit with an anchor lock outside the bearing with several allen headset screws.

A large bore bearing used on a conveyor drive unit would typically have a split case and or bearing and if the bearings are used for the over under pulleys both pulleys will have a longer shaft to allow for the driving pulleys to connect to the drive and driven gears and a chain drive case from the reduction gear box and electric motor which power the drive gear.

The driven gears and sprockets are held in place with key stock and set screws in a keyway cut into the inner bore of the gear or sprocket and a mating groove/keyway in the shaft it is mounted to with set screws normally

A set screw is normally set in place with a tiny dimple drilled into the shaft or keystock to help hold the set screw point in place and to keep it from vibrating loose.

Please tell us more or post some good pictures if possible.

lzaharis ■

The problem as stated is quite specific, the adaptor sleeve (also called a taper sleeve) used for mounting a taper bore bearings (as produced by SKF, FAG et al) has failed.

Sorry Izharis, I really don't see where "Ringfedder" can be inferred, or understand the statement "inner bore of the bearing should not have a tapered bore period unless something has drastically changed in 9 years." Suggest you check the SKF and FAG web sites.

I have used SKF/FAG bearings mounted on adaptor sleeves for 40 years! During this time I have never come across an adaptor sleeve failed in this way. I would be discussing this with the supplier as it sound like a faulty component. ■

To my knowledge we never had bearings or used bearings with tapered bores in the mine where I was employed.

I never saw an adapter sleeve for bearings in use for our applications either and I meant no disrespect to anyone.

I am always willing to understand and learn about something new to me.

lzaharis ■

Maybe it has something to do with your location and industry in the US?

I have found that things I take for granted frequently cause my American colleagues a degree of confusion. ■

The Hewitt Robins and Continental conveyors I am familiar with always had pulleys-head and drive/driven-over under wrap with shafts that were keyed and had outside lock rings and set screws, or were stationary bearing mounts on the conveyor drive frame and the shafts continued into the gearboxes or chain cases and gear cases where they were secured to the gears or sprokets.

Most of our heavy 4-15/16 inch plus bearings were SKF tapered barrel rollers in grease with split housings and no sleeves of any kind. ■

Greetings and salutations Sganesh,

Thanks for the photo images until you take the damaged sleeve to a metalurgist for for analysis you can not rule out metal fatigue poor quality of materials or poor smelting practices. ■

We use 60mm 22213 bearings from SKF or FAG and never had any problem.

We just do up the nut "tight", load the housing with grease and that's it. Our speeds are 100 rev/min max.

EDIT

Have you had failures with SKF or FAG components? If not, try them.

If SKF or FAG have failed, drag the local rep in and demand some answers! ■

inspection of the bearing itself is a good way to do a preliminary analysis of the cause of failure.

If it cannot be determined by that inspection then as others have suggested hire a good metalurgist to do a root cause failure analysis.

Here is an excellent article on bearing failure analysis.

http://www.alliedbearings.com/downlo...eandcauses.pdf

The failure of the sleeve may only be the end result and not the root cause of the failure. Improper clearances for example can cause loose fits and improper loading leading to failure.

I know this may sound stupid but I have seen it happen many times and saw millwrights install the fixing rings in both bearings. One bearing is to be fixed and the other is to be floating. In other words the fixed bearing has the fixing ring(s) installed and the floating bearing does not have any fixing rings allowing it to move as the shaft expands and contracts.

Just some food for thought.

Gary ■

Good one, Garry!

Michael Reid. ■

Hello Gary,

I guess the PM system is not working again, Herr Wolbier has been having some problems with it.

Heres my home e-mail .

lzaharis@lightlink.com ■

Greetings Sganesh,

What Aree the revolutions per minute(RPM) of your application?-if the adaper is not tight enough or the application speed is to high etc. that would explain a lot also.

lzaharis ■

Greetings and salutations SGanesh,

Judging by what you mentioned and the low speed that designer has for his adapter sleeves and bearings(100 RPM), your variable speed may be your problem-unless this is the first set of sleeves that went bad of course.

I would seriously want to use a paint stick(to note location of the locking sections/parts of the sleeve and a base mark on the bearing housing) and possibly a non contact thermometer(infra red I think-sorry its been along time) to check the sleeve temperatures during run times etc. ■

In this life you sometimes need to spend a bit of money. Time to stop the speculation and cut to the chase.

Send the failed parts for analysis to a reputable metallurgical laboratory. ■

Good one Designer! Our correspondent has had all the correct advice. Time to act on it.

Michael Reid. ■

There was no mention of bearing failure, only sleeve failure. Consider the sleeve as a cantilever, encastre by the threaded portion, and further consider if there is any untoward deflection being produced by a small shaft. This would be a sure source of shear. Try saying that after a few pints. It looks like an inappropriate application of a self aligning bearing. ■

Hi sganesh,

We use this type bearing in a variety of machines. If the bearing rolling elements and cage are in working order this failure is the symptom of an improper installation procedure. Shown is the broken sleeve and a lock nut. This lock nut is strictly for remvong the sleeve during the disassembly process. There should be another lock nut that fits a thread on the shaft; this is the shaft nut that pushes the tapered sleeve into the bearing thereby adjusting the clearance. This second (smaller) nut is the primary device for adjusting bearing clearance and keeping the bearing in place. The shaft nut mounted on the tapered sleeve must not be torqued to nominal torque, but only "snug". Use a mechanical device to keep it in from loosening or a shaft nut with a clamping screw.

The break looks like a ductile fracture at the end of the thread. This is usually due to a pull force exceeding the steel's tensil strength. This is why I think you may be overtightening the sleeve's shaft nut - the nut literally pulls the sleeve apart. ■

???

Not according to the SKF web site mounting instructions on the use of adaptor sleeves! ■

Hi designer,

I am sure that many OEM's use the standard SKF or FAG mounting application you are mentioning. There are optional ways to install them as well. Please find attached the mounting version I referred to in my earlier post. Either way, it depends on how sganesh's installation is configured. It would be extremely helpful if he had a drawing or a photo what the installation looks like.

Attachments

spherical roller bearing (PDF)

■

Ralf,

It's quite clear what he is using, a standard double row self aligning spherical roller bearing mounted on a standard taper sleeve. Sorry, it's nothing like your illustration.

All the relevant information can be found on the SKF web site. ■

Got it. I should have looked at the web info detail first. Nonetheless, this leads me still to believe that there is a good chance to overtorque the shaft nut thereby providing too much tension on the sleeve part. ■

sganesh

Have you had the failed sleeves independantly analysied??

Have you discussed the failure with the bearing manufacturer??

Who is the bearing manufacturer??

These are things you must do and not rely on this forum to slove your problem! ■

Hello sganesh,

I am in the clear now about the type sleeve you have. Sorry about that. The torque you apply to the sleeve is really more a function of what kind of final bearing clearance you are after and from what basic nominal clearance you are starting from. This could even be related to a shaft OD tolerance issue. Depending on the fit this requires more or less torque to pull the sleeve into the bearing. How much radial or axial play do you adjust to? I am with Roland, more informatin would really be necessary to be able offering further assistance. ■

...Which tempts the question. What is different in the new installation? ■

Originally Posted by sganesh

But the supplier never responded back.

They need a good kicking then!

Was the "supplier" also the "manufacturer"? I usually find I get better treatment by going to the manufacturer. Was the manufacturer SKF or FAG?? ■