Force required to spin shaft
Force required to spin shaft
(OP)
I have a 25mm OD Al 6061 shaft supported by a ball bearing on each end. How can I find the force required to rotate the shaft from rest?
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Force required to spin shaft
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Force required to spin shaftForce required to spin shaft(OP)
I have a 25mm OD Al 6061 shaft supported by a ball bearing on each end. How can I find the force required to rotate the shaft from rest?
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RE: Force required to spin shaft
RE: Force required to spin shaft
2) Try to get information from the bearing manufacturers- may or may not be easy.
3) Check a machine design or mechanical engineering reference and see if they have any info on bearing drag forces.
There will be some drag due to the bearings. There will be an additional torque required due to inertia, that may or may not be significant, depending on the speeds involved.
I would suppose that drag from the bearings would be highly variable depending on the amount, kind, and temperature of the grease; the construction of seals, if any; how worn the bearings were, lateral loads on the bearings, etc. The drag may depend on how tight the retaining nuts are fastened, also.
Maybe some additional information on your part would get more helpful answers here.
RE: Force required to spin shaft
RE: Force required to spin shaft
RE: Force required to spin shaft
Area moment of inertia may be the same, but the mass moment of inertia is density-dependent. Less mass = smaller "J" = higher rotational acceleration for same applied torque.
RE: Force required to spin shaft
RE: Force required to spin shaft
The main difference in the shafts from a force standpoint would be the inertia- and that looks pretty low either way.
RE: Force required to spin shaft
RE: Force required to spin shaft
RE: Force required to spin shaft
http://www.webexinc.com/dsi.asp
RE: Force required to spin shaft
RE: Force required to spin shaft
RE: Force required to spin shaft
search on thomasregister dot com for "roller coating" and you'll get a few companies that provide friction coatings for rollers - it may help prevent the slipping you are experiencing without designing a new part. Else you can look at plastic rollers as well - lighter than aluminum and with the right material choice it may prevent scratching even if the rollers slip on the film. Rather than ball bearings if you redesign or rebuild - you also may want to check into composite bearings as for low loads they can provide less friction than ball or roller.
RE: Force required to spin shaft
RE: Force required to spin shaft
I think I would go with a hollow steel
shaft, I would be a little worried about
the expansion of the aluminum shaft
increasing the preload on the bearings.
RE: Force required to spin shaft
RE: Force required to spin shaft
Incorrect
Correct
RE: Force required to spin shaft
RE: Force required to spin shaft