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From reviewing nomenclature to calculating the load deflection, to understanding Dynamic Loading and Fatigue Life, you can access valuble information to help determine the correct belleville, spring or disc washer for your application

Nomenclature

O.D = Maximum outside diameter (upper surface)
I.D. = Minimum inside diameter (bottom surface)
h = Conical disc height (cone height)
O.H. = Overall height (Y + h)
t = Actual thickness of disc
ß = Cone angle of disc
R = Radius from center line to load bearing circle (bottom surface)
M = Ratio surface

µ = Poisson's ratio
E = Young's modulus (30,000000 for steel)
f = Deflection of disc
a = Ratio of diameters (O.D. / I.D.)
P = Load in lbs at a given deflection
Pf = Load in lbs. flat
X = Sinß(t)
Y = Cosß(t) To calculate the load accurately, the following important factors must be considered.

A well designed disc spring has radii at all corners to reduce stress concentrations at the edges. A suitable radius is approximately equal to t/6. This radius further reduces dimension R Usually the overall height of the disc spring is specified because it is easy to measure and control. The cone height h, on the other hand, is difficult to measure

For an approximate calculation, h = (overall height - t ) is acceptable. However, this is not accurate. In fact, h = (overall height - Y), where Y = Cosß • t. For small thicknesses (under 2 mm) this is not significant. With thicker disc springs, this becomes a major factor for accurate load and stress calculations. This has not been adequately considered in previous technical literature.

Precise load and stress calculations require the determination of the disc spring angle ß. Since this is not easily determined by physical measurement, we have developed a computer program that calculates the precise angle and arrives at the exact dimension for conical height h. This then determines accurate load and stress with accuracy.