bearing loss

[wangp1283]

Hi, can anyone give me an idea of how significant are bearing rolling losses in a gear train (or more generally, a hard rolling body on a hard flat surface).

Thanks.

 

[electricpete]

NTN gives a formula:

M = Mu * P * (d/2)
where
M = friction moment
P = radial load
d = bearing bore diameter
Mu = friction coefficient = 1.0-1.5E-3 for deep groove ball bearings and cylindrical roller bearings, 1.2-1.8E-3 for angle contact ball bearings, 2.0-3.0E-3 for thrust roller bearings etc.

You can compute your fricttion loss power from frictional moment using first principles
Power = 2*Pi*M * rotational frequency

F.A.G. "Rolling Bearing Lubrication" is available for free at

http://www.fag.com

( you have to register). It has a much more detailed formula with a load-dependent portion and a load-independent portion, depending on viscosity and other factors.


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