KEVOS® MAKEOS · Springs

Disc (Belleville) Spring Load and Stress

What force and stress does this disc spring, or stack, give at a deflection?

Load, flat load and top inner-edge stress of a disc (Belleville) spring by the Almen–László method, and the force and travel of series and parallel stacks.

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How this tool works

Inputs, units and where to find them

InputUnitTypical source
Outside diametermmOutside diameter from the catalogue.
Inside diametermmInside diameter from the catalogue.
ThicknessmmDisc thickness.
Cone height h₀ (free height − thickness)mmUnloaded height l₀ minus thickness t, from the catalogue.
Elastic modulusGPaElastic modulus of the spring steel.
Poisson’s ratioPoisson’s ratio (about 0.3).
Deflection of one discmmDeflection of a single disc at the working position (no more than h₀).
Discs in series (alternating)discsNumber of single discs (or parallel sets) stacked in alternating directions.
Discs in parallel (nested)discsNumber of discs nested in the same direction in each set.

Method and formulas

  1. δ = De ÷ Di; K₁ = (1/π)((δ − 1)/δ)² ÷ ((δ + 1)/(δ − 1) − 2/ln δ).
  2. F = 4E ÷ (1 − ν²) × t⁴ ÷ (K₁De²) × (s/t) × [(h₀/t − s/t)(h₀/t − s/2t) + 1].
  3. σI = −4E ÷ (1 − ν²) × t² ÷ (K₁De²) × (s/t) × [K₂(h₀/t − s/2t) + K₃], with K₂ = (6/π)((δ − 1)/ln δ − 1)/ln δ and K₃ = (3/π)(δ − 1)/ln δ.
  4. Stack force = F × parallel count (friction neglected); stack travel = s × series count.
  5. Example: the default disc gives 4,762.1 N at 1.05 mm deflection and 5,897.9 N at flat.

Limitations

  • Discs without contact flats; friction in parallel stacks raises loading force and lowers unloading force.
  • Fatigue needs the tensile stresses at the lower edges (σII, σIII) and the maker’s fatigue diagrams.
  • Example values are illustrations. Replace them with values for your actual task.

Typical uses

  • Size disc stacks for bolted joints, clutches and valves
  • Check load at a set deflection
  • Compare series and parallel stacking

Who it is for

  • Design engineers
  • Spring buyers
  • Maintenance engineers

What you get

  • Force of one disc and of the stack
  • Force at flat
  • Top inner-edge stress (σOM and σI)
  • Stack travel

Interpreting the result

  • Keep the working deflection at or below about 75% of h₀ for a predictable, near-linear characteristic.

References

  • Machinery’s Handbook, 29th edition (Industrial Press, 2012), printed pp. 350–359. Topic reference; no source tables or recommended settings are reproduced.
  • EN 16983:2016 Disc springs — Quality specifications — Dimensions; EN 16984:2016 Disc springs — Calculation

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Open the Disc (Belleville) Spring Load and Stress calculator