Ball Bearing Gurus, please

[MBfreak]

We are working with a differential/reverse gear assembly for a Radical racer.

Very well made stuff with tight tolerances.

At assembly we need to mount a ball bearing on a 37 mm hollow shaft, as the last step. The bearing is a very tight fit but removal ( press force around 40kN) was easy since we did not transfer any undue loads into the diff/planetary gear assembly.

Pressing it back on , which can only be made when asembly is otherwise complete, is different. No way to directly support the hollow axle to counteract the pres force.

Is it possible to heat a standard 2Z( rubber lip seal) ball bearing in oil to around 100 degr Centigrade , 200 degr F?

Best regards

Ola

 

[shawnspeed]

I would hope it would take that kind of heat ...if not you will have an oily mess any way you look at it...our gearbox & rear end on the race car regularly saw 350-400 degrees F for intermintent periods...250 F being a normal range in warm weather...Shawn

 

[MoonRise]

Usually, no.

SKF says to not heat sealed bearings higher than 175F max, typical is more like 150-160F.

As well, check service temp limits of the bearing and make sure it is 'OK" for the environment you are putting it into.

 

[Garage Rat2]

COPY EDIT: At assembly we need to mount a ball bearing on a 37 mm hollow shaft, as the last step.

What is the part number of the bearing your are using? I'm guessing you are mounting
bearing by it's outer ring in a hollow "tube" arrangement. When you mounted the bearing and installed shaft in inner ring, was the shaft free to turn? Standard size OTC bearings have shaft mounting sizes breaking on 5 mm. increments. Does yours have "/37" included in part number?

 

[A_Pmech]

A combination of heating the bearing and cooling the shaft tube in dry ice or liquid nitrogen should provide about 500F of fit.

Work fast! On an assembly that size, from the time you pull the bearing off the heater and the shaft out of nitrogen you have about 10-15 seconds to get the bearing seated. Have a tube at the ready from a non-marring material which fits the inner race of the new bearing but over the hollow shaft. If the bearing hangs up on a burr you can usually avert disaster by giving it a few swift taps the instant it hangs up.

 

[rlitman]

The shaft is hollow. Can you plug the bottom end and fill it with liquid nitrogen?
If you cannot get liquid nitrogen, you can use a mixture of dry ice and acetone.

 

[MBfreak]

Hi guys,
thanks a lot for the answers.
We heated the bearing to 90C in an oven, which gave us a 0,03 mm ID increase.
We pressed it on and the force was less than 5 kN, so no problem for the rest of the assembly

Again, tnx.

Ola