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Bearing formula

Bearing formula

Bearing formula

(OP)
Can anyone recommend a good resource for formula relating to bearing load,torque,power transmission and radial force.
We manufacture large rubber lined bearings, and I'm trying to determine an approximate working pressure when the customer has only supplied the power transmitted throught the shaft(Kw).

Is possible to do this? I also have figures for dimensions,rpm,max working pressure but am struggling to find any formulas that relate to bearings, other than ball bearings.

any help greatly appreciated.

RE: Bearing formula

You need info on the applied loads, moments and their locations.  You cannot get bearing loads given only the power transmitted through the shaft.  Once you have the loads and the dimensions then you need to do "free body analysis" which is summing forces and moments to solve for the unknown bearing reactions.

RE: Bearing formula

Search on "hydrodynamic lubrication."  True hydrodynamic lubrication involves a circular shaft running in a very slightly larger circular bore.  Your rubber bearing, when loaded, will not be truly circular, so conventional hydrodynamic lubrication analysis may not entirely apply.

BobM3 was right on about needing to know more than just power.  Many bearing manufacturers' catalogs have excellent technical sections showing how to calculate loads from power, speeds, and geometry.  These calculations are not specific to any particular type of bearing.  

The actual nominal pressure is actually pretty simple to calculate, if the radial load is known - assuming zero pressure at zero load, and good shaft alignment.

p = P / (D x L)

D = shaft diameter, inches
L = bearing length, inches
P = load, lbs.
p = pressure, psi

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