Proper Bearing Selection

[Rooster35236]

This is my first post here!

I have been working on product development for a customer and because of the NDA there isn't a whole lot I can say about it but the project needs a specific bearing. It must have an eccentric locking collar which would accept roughly a 1/2" bore, originally we went with an ER-201-8 bearing because of the size and the load rating but the issue we are having is that is does not spin freely enough. Ideally, we need a bearing that has the resistance of a rollerblade 608zz bearing but is much larger and can handle higher temps of what a skate wheel would generate. Any help would be greatly appreciated!

 

[Skogsgurra]

Any cost restrictions?

Gunnar Englund

http://www.gke.org

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Half full - Half empty? I don't mind. It's what in it that counts.

 

[Rooster35236]

Cost is not huge restriction at this point, once the prototype is finalized we are going to need thousands for full production.

 

[tbuelna]

From your OP description, it seems like the difference in running torque between the two bearings is due to one using (contacting) rubber seals and the other using (non-contacting) shields. Obviously, a bearing using non-contacting shields will have lower running torque, and should "spin more freely". But on the other hand, shields are not as effective at preventing grease leakage as rubber seals are.

 

[MikeHalloran]

If the running torque of a -zz bearing prevents your design from working, it may be time to consider a different design.



Mike Halloran
Pembroke Pines, FL, USA

 

[Skogsgurra]

An active magnetic bearing is the ultimate solution. But there are costs, power losses (electrical) and some size restrictions. Commercially available from several suppliers.
There are also passive solutions, but Earnshaw has objected to that for almost 200 years.

Gunnar Englund

http://www.gke.org

--------------------------------------
Half full - Half empty? I don't mind. It's what in it that counts.

 

[Tmoose]

"It must have an eccentric locking collar".

I am sorry to hear that.

If the shaft spins and the load is one directional ( like a belt driven fan) keeping the inner race locked to the shaft can be a huge problem. The greater the shaft to bearing clearance ( I'm only talking 0.001 or 0.002" diametral clearance, which commonly results from commercial shafting) , the more likely things are to wiggle loose and destroy each other. Tightening the collar in the direction of rotation is supposedly only enhanced if slippage occurs, but radial forces like belt loads or even gravity with a fat rotor have no problem sliding the shaft radially sideways in the essentially 2 point contact of the eccentric and bearing inner race.