De /mm = External (Outside) Diameter

De' /mm = Point at which the Load is Applied on the Disc Spring's Outside Diameter
(For Disc Springs with Load-Bearing Surfaces)

Df /mm = Point at which the Load is Applied on the Disc Spring's Inside Diameter (For Disc Springs with Inside Diameter Slotting)

Di /mm = Internal (Inside) Diameter

Di' /mm = Point at which the Load is Applied on the Disc Spring's Inside Diameter
(For Disc Springs with Load-Bearing Surfaces)

Do /mm = Diameter of the Circle Through the Mid-Point of the Disc Spring Cross Section

E /N/mm2 = Modulus of Elasticity

F /N = Load from a Single Disc Spring

Fc /N = Calculated Load of a Single Disc Spring in the Flat Condition

Ftot /N = Total Load for a Disc Spring Component Consisting of n Disc Springs in Parallel

FtotR /N = Load from a Disc Spring with Consideration Given to the Effects of Frictional Influences

Fo /N = Maximum Load of a Single Disc Spring Before to the Flat Condition (Curve Parameter > V2)

Fu /N = Minimum Load of a Single Disc Spring Affer
Working Through the Flat Condition(Curve Parameter > V2)

*F /N = Decrease in the Disc Spring Load due to Relaxation

Lc /mm = Calculated Length of the Spring Stack or Spring Assembly in the Fully Compressed State

Lo /mm = Length of the Unloaded Spring Stack or Spring Assembly

Ltest /mm = Testing Height Under Load for a Disc Spring Stack

R /N/mm = Spring Rate

Ra /u m = Surface Roughness

Rm /N/mm2 = Tensile Strength

S = Theoretical Mid-Point of the Disc Spring Cross-
Section

W /N mm = Spring Work

d1 /mm = Inside Diameter of CB Fastener Bellevilles (DIN 6796)

d2 /mm = Outside Diameter of CB Fastener Bellevilles (DIN 6796)

h /mm = Unloaded Free Height of @ Fastener Bellevilles (DIN 6796)

ho /mm = Dish or Maximum Deflection Without Load Bearing Surfaces (ho = Io - t)

h'o /mm = Dish or Maximum Deflection
With Load Bearing Surfaces (h'o = Io - t)

i = Number of Si ng le Disc Springs or Disc Spring
Components Alternately Arranged to form a Disc Spring Stack (i=No. of Disc Spring Components in Series)

Itest /mm = Testing Height Under Load for a Single Disc Spring

Io /mm = Unloaded Free Height of the Single Disc Spring

n = Number of Disc Springs Arranged in Parallel to
form a Disc Spring Component in a Disc Spring Stack
(n=No. of Disc Springs in Parallel per Component)

s /mm = Deflection of a Single Disc Spring. Note: (s) is also used to denote the material thickness
for CB Fastener Bellevilles (DIN 6796)

s tot /mm = Total Deflection of a Disc Spring Stack or Disc Spring Component Assembly Without Regard to
Friction (Recomended Maximum Value - s (tot) = 0.75 (Lo - Lc))

t /mm = Material Thickness for Disc Springs

t' /mm = Reduced Material Thickness for Disc Springs with Load-Bearing Surfaces

Wm' Wr /mm = Friction Factors (Refer to Chapter No. 9)

d /mm = Ratio of Spring Diameters d = De/Di

u /mm = Poisson's Ratio

sI, sII, sIII, sIV, sOM /N/mm2 = Calculated Material Stresses from Point I to OM on the Disc Spring Cross-Section

so /N/mm2 = Calculated Upper Stress in Disc Spring Material in the Dynamic Loading Condition

su /N/mm2 = Calculated Lower Stress in Disc Spring Material in the Dynamic Loading Condition

I,II,III,IV,OM = Defined Positions on the Disc Spring Cross-Section