creating mounting area for a bearing

[Anonymous]

I am still new to Fusion 360.

I am wondering the correct way to create a mounting recess for a ball bearing.

Currently, what I am doing is taking the OD of the bearing and creating a hole that is .05 mm larger than the OD and .05mm deeper than the depth of the bearing.  I haven't fabricated the pieces yet, but the intended material is 6061 aluminum.  

Does anyone have a guide on this?

Thanks!

[TheCADWhisperer · Accepted solution]

The outer bearing race should be a light press fit into the hole.

The inner bearing race should be a light press fit onto shaft.

You want the relative motion to be between the balls (or rollers) and the races, not between the races and mount hole (or shaft).

The bearing manufacturer should have some data sheets.

[mcnurlin · Accepted solution]

like anything this is a very complex problem. It depends on the application the bearing is being used for. For instance if you a have shaft with a bearing on each end. You may want the inner race of each bearing to be fixed rigidly. So the inner races will be a press fit and held with a retaining ring or nut. This locks the inner races and prevents fretting on the shaft. The outer races are a different story. One of the bearings should have a press fit and a retaining ring or nut holding it in place. This will ensure the shaft does not move from side to side. The outer race of the other bearing will need to be a slip fit in the housing and there should be enough room in the bore for the bearing to move in and out enough to allow for manufacturing tolerance and thermal expansion of the shaft and structure supporting the outer races.

Bearing suppliers like SKF have very good referance material that sugget the proper mounting as well as shaft and bore dimensions for all of their bearings.

Improper bearing mouting is an easy way to turn a good design into a maitaince nightmare.  

[kshea9RNL8 · Accepted solution]

As TheCADWhisperer and mcnurlin have mentioned contact the manufacturer if it's a premium bearing like SKF, the company is very responsive and helpful if you email as well as the fully informative online documentation but can be a bit troublesome to sort through if you are unfamiliar.

It all depends on application, the higher the rpm, and/or load and/or  bearing precision and/or high frequency of use the closer you will need to machine to recommended specifications for reliability.

If it's not a critically used part with low rpm and load with infrequent use then you can get by with less then the optimal, .o5 would give a pretty tight fit actually.

If you machine it a bit too loose there is always Loctite bearing retainer 🙂