Ball Bearing Manufacture

[spedtoe169]

How are ball bearings manufactured? There are many that I've seen that don't seem to be able to be disassembled. The balls are trapped between the inner and outer race and the races are solid pieces. How is this type of bearing made?

Also, what type of operations do bearing balls have to go through to be made so perfectly round? I know that very very tight tolerances are kept on many ball bearings, there has to be some trick to this.

 

[diamondjim]

The answer to you first question is that they
are Conrad loaded, ie. the inner ring is moved
fully to the outer race and the ball are then
inserted in that opening. It limits the amount
of balls to about 1/2 the amount that could
go in if they were filler plug loaded. After
the balls are loaded the inner ring is forced
back to the centerline and the balls scoot
around the ring. Often a cage with open pockets
is inserted between the balls. Normally for
this type of loading the difference between the
id of the outer race and the od of the inner race
is equal to the ball diameter thus allowing the
insertion of balls when the inner is displaced.
To be disassembled, the cage would be removed and
the balls forced to one end so the inner ring
can be displaced to allow the balls to come out.

 

[jet1749]

As far as tight control of bearing tolerance goes, this is how I've seen it done at an SKF factory. Individual balls (or rollers)are not manufactured to produce specific bearing clearances. Rather they are made to conform to a tolerance range. After grinding operations are complete they are automatically sorted according to particular size ranges. They are then picked and assembled to produce a bearing with a specific bearing clearance grade. Interestingly I was told by SKF that their "explorer" range of high quality bearings were not specifically designed, but came about by accident when they realised that modern equipment etc was producing the existing bearings to a higher quality. When this was realised they relaunched the product.

 

[willdo]

Here's some info:

http://www.ntn.ca/howitsmade.wmv

 

[KnifeKnut]

http://www.sheldonbrown.com/rinard/ball.htm

http://yarchive.net/metal/ball_bearing_manufacture.html