assembly of bearing

[moparti]

Hi All,
I have the peculiar doubt, can a bearing be fitted into a housing where the housing surface is not ground but is spark eroded? to reframe it, if the OD tolerance be maintained but the surface roughness maintained to that obtained from a spark (EDM) but not a ground finish, can it still be an appropriate assembly. The product I'm talking about has high tolerances on endplay and radial play.
Thankyou very much,
Lalitha

 

[MadMango]

You could look into the use of tolerance rings to avoid this worry, and avoid a secondary operation for the housing for the bearing.

MadMango
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[EnglishMuffin]

If you're talking about a rolling element bearing with an outer race, and you can achieve the dimensions and geometrical tolerances specified by the manufacturer, then the surface finish should not be too important, within reason. But if the peak to valley height is a substantial percentage of the tolerance, I would be a bit worried, because the surface could crush and the tolerance would then loosen up.

 

[ccw]

Hi Moparti,
Do you want to plunge EDM a blind hole for the bearing or wire EDM a through hole for the bearing? Based on my experience the wire process can be controlled better than the plunge unit but there has to be a start hole fashioned somehow.

The wire process can attain very good bore tolerance, in the hands of a good machine and experienced operator, sufficient to mate with the outside of the outer race of a bearing, particularly if the bore length to bore diameter is < 1.

Plunge EDM'ing may require multiple setups to get a perfect blind hole cylinder with square shoulder.

 

[moparti]

Thank you very much for the reply's it was of great help.
We are still working on the different layouts, and would do a cost & Effect analysis to opt for the best alternative. Appreciate your help and thankyou once again.