Angular contact bearings 7201-2RS

What a fabby question

IMHO the stamped edge is the "key" to your problem

Which way round it is though....

I would pop them both off though, just to be sure, since it is a critical application

If one happens to be the wrong way round, what are you going to do? sue?

And My guess is:

The stamping is normally the weak point, so it's the outside part

Edited By Ady1 on 18/06/2015 00:47:57

Below is an image of a 7201-2RS bearing. You can plainly see the diiference between the thrust and non thrust faces.

Paul

Wow!

Thankyou for that Paul. You wouldn't happen to know what the contact angle is?

Just gone back and checked the link from Mike C and there is no mention of contact angle.

From your picture Paul, the ID side is the thurst side.

I will have to see what Simply Bearings come back with.

Cheers Michael.

Michael.

As far as I am aware they are 15 degree which I believe is most common and supplied without question. 25 degree is only supplied on request.

I run the bearings back to back (idents facing each other) but because they are not a matched pair I use shims between the outers to obtain the correct loading. I use these on my cnc router for the ballscrews to take the thrust loads on all the axis's.

Hope that helps.

Paul.

Hi Michael,

Sorry for delay in reply. Just finished with visitors.

B = 40 Degree contact angle.

C = 15 Degree contact angle.

A = 30 Degree contact angle.

Above are usual specifications for A, B and C suffix on angular contact ball bearings. There are other contact angles once you start going into certain super precision match pairs depending on manufacturer, but generally, above is the norm.

See below the picture of what we have in stock. It looks like Pauls picture. It is 7206 B 2RS, so contact angle is 40 Degree. Easy to figure out which way is which:

If you want to open yours to check, you will need to use a very thin flat screw driver and wedge it in carefully in between the inner ring and the seal lip to 'pop it off', to ensure least damage.

Ketan at ARC.

Edited By Ketan Swali on 18/06/2015 11:34:12

Of course there is another way...

If you press the inside into the outside, from the 'correct' diirection the bearing should get slightly 'thinner' than if you apply force the 'wrong' way.

Neil

As a general guide for angular contact ball bearings, have a look at the link below.

As a general idea/guide to meanings of suffixes, read page 504 in the link.:

**LINK**

Although the bearings we sell are not made by SKF, most bearing manufacturers and traders use SKF referancing system for bearing designations, with small variances.

Ketan at ARC.

Personally I'd pop the seals off and have a look as these look nothing like any angular contacts I have fitted.

I wouldn't be surprised to find they are just deep groove bearings wrongly marked.

Uhhhh probability of Michaels bearings being just deep groove bearings are low. Dont scare him

Poping off a seal may reveal a slight difference in the internal design to accomodate the seals they have used.

Ketan at ARC.

If the bearings you have are 'B' = 40 Degree contact angle, with grease lubrication - which probably they are because of rubber seals (RS), the limiting speed rating with this specification is around 17,000 rpm as a single, or 15,000 rpm as a duplex (face to face or back to back). If you remove the seals, remove the grease and oil them, then the limiting speed 24000 rpm as a single, or 20,000 rpm as a duplex arrangement.

If you were using contact angles A or C, you would get higher speeds, but not easy to find them with rubber seals.

Ketan at ARC.

Useful stuff to know - thank you Ketan

IanT

Extract from NACHI catalogue for suffix A, B, C:

Limiiting speed from NACHI catalogue, for 7201 A, B, C 'open' type, to be used as 'general guidance' only. 2RS reduces limiting speeds due to the friction of the lip of the seals against the inner ring, but still, you get the general idea:

Ketan at ARC.

Edited By Ketan Swali on 18/06/2015 18:15:30

Small correction, the above picture is for 7201 B 2RS, and not 7206 B 2RS. .... Sorry.

Ketan at ARC.

Thanks for all the input.

Simply Bearings have not been in touch so I think I will send them an email perhaps refer them to this thread!

I don't fancy popping a seal off because if they are labled wrong I am stuck with them.

If they reply I will let you know what they say.

Cheers Michael.

If you look at http://medias.schaeffler.com/medias/en!hp.ec.br.pr/72..-B-2RS*7201-B-2RS-TVP you will see the dimensions they should be. The outer ring look like more of a giveaway

Why not just send them back an purchase something that is easier to identify?

Simply bearings offer

No Quibble 100% refund guarantee

We offer a 100% no quibble satisfaction guaranteed refund policy!

If you are not 100% happy with the quality or any other aspect of the goods we have supplied then please return them and we will be only too happy to refund you.

We are happy to accept returned goods within 90 days of purchase.

On a personal note, do not like cheap bearings as their quality can be a little suspect.

Bob

A bit late but FWIW...

Is there a letter after the 7201 number on the bearing? As others mentioned, that would indicate the angle. B is 40 degrees and that is usually very easy to see. I'm guessing yours is C which is 15 degrees so hard to tell.

If you measure the entire outside diameter of the inside race or the inside diameter of the outer race it might be easier to tell since you'd get double the difference than measuring the thickness of the race.

Every angular contact bearing I've seen had the thinner inner race on the ID side. Of course that doesn't mean it's always the same and I've never had Chinese angular contact bearings.

Although with a shallower angle it might be more tricky, but you can lightly press the inner race against the outer race to both sides and compare. On regular ball bearings the play is pretty even overall. On B angular contact bearings the difference is very obvious and you can't really pres the inner race much at all to one of the sides. With a shallower angle the difference might be smaller but tehre's a chance you could feel it. The side you press toward with less play would be the direction of the bearings facing each other to creat thrust (sorry about the clumsy explanation, it's not my first language).

I guess you probably solved the problem by now

Loosely related - Does anyone know what the effective contact angle of magneto bearings usually is?

John

-

Hi

Below is the reply from simply bearings.

Hello Michael

Thank you for your enquiry. I have checked the remainder of the 7201 bearings as ordered and the direction of thrust is against the non printed side. The axial load is to be presented to the non printed side. I hope this makes sense, these small ones often bring up this question, as they are generally too small to feature any visible physical difference in the races which is commonly found.

If you require further assistance then please do not hesitate to contact me as I will be more than happy to help.

Best Regards

Couldn't be more ambiguous - depends where you are standing! Surely the printed face is to be loaded under compression. I'm sure he knew what he meant and I think we know the correct answer.

He assumes the load is what is presented to the inner race.

If you insist on asking you will get some form of answer....

Edited By Muzzer on 13/07/2015 20:23:18