Hope the group collective can help.
If a bearings dynamic load is 14.8 KN and static load is 7.8 KN. Am I correct in working out that statically the bearing will take a weight of
And dynamically it would be approx equivalent to 1.5 metric tonne.
I know that Newton is a measure of force, mass x acceleration but using gravity in this to give me an idea of the forces involved.
Please let me know if this makes sense or if I am wrong.
Adrian
What sort of bearings are we talking about here? For ball and roller bearings, the static load is that which causes a specific amount of plastic deformation (one ten thousandth of the bore diameter, if I recall correctly). The dynamic capacity is the load which will cause 10% of bearings to fail by fatigue pitting in one million or perhaps three million revolutions (depending on the manufacturer). In the old old days I thing it was RHP bearings who did their sums on 300 million revs, which made their performance look very inferior to SKF, where the calc was based on one million. The point is, the "capacities" are based on some performance criterion.
Your force convertions are OK, I think.
You are right. On this planet.
Nick
SKF deep grove single ball race with 25 mm internal bore 62 mm external dia.
If the calcs are OK then, it will do, Max rpm will likely be around 300 rpm max and static loads around 150 kg for two bearings.
Thanks
Adrian
Sorry that should be 52 mm external dia.
Adrian
Assuming 150 kg per bearing your "L10" life (ten percent probability of fatigue) will be about 20 years continuous operation. This assumes it doesn't overheat and cook the grease or that it doesn't fill up with grit or water.
That will certainly be longer then the predicted life of the kart.
Grit and water are the expected killers, so must keep pumping through the grease.
Adrian
On or around Wed, 04 Apr 2007 15:51:06 -0500, Adrian Hodgson enlightened us thusly:
I think that sounds right. static load is less than dynamic.
beware of shock loading if the application is subject to such things.
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