What is a Standard Disc Spring?
A standard disc spring (also known as a Belleville spring or conical spring washer) is an annular coned disc engineered strictly to the dimensional, mechanical, and material specifications of DIN 2093 (superseded in European norms by DIN EN 16984 / DIN EN 16983). Its cross-section is rectangular with constant thickness t, and its outer diameter D, inner diameter d, and cone free height h₀ adhere to standardized dimensional progressions.
Typically fabricated from certified 50CrV4 (1.8159 / AISI 6150) chromium-vanadium spring steel, individual standard disc springs support extreme axial loads from 5 kN to over 300 kN within minimal axial packaging, ensuring universal interchangeability across worldwide equipment manufacturers.
DIN 2093 Three Geometric Series (A, B, C)
DIN 2093 classifies standard disc springs into three dimensional series based on the ratio of initial cone height to thickness (h₀/t):
| Dimensional Series | h₀/t Ratio | Load-Deflection Curve Profile | Primary Engineering Application |
|---|---|---|---|
| Series A | ≈ 0.40 | Virtually linear curve, highest stiffness | Sealing gasket compensation, precision axial clearance shimming |
| Series B | ≈ 0.75 | Standard regressive curve (degressive) | High-tensile bolted joint preload, stamping die stripper plates |
| Series C | ≈ 1.30 to 1.50 | Pronounced regressive / flat plateau curve | Clutch release mechanisms, constant-load valve packing |
Standard Manufacturing Scope
TOSTA standard disc springs cover the complete DIN 2093 dimensional range:
| Parameter | Specification Range | Engineering Details |
|---|---|---|
| Outer Diameter (D) | 8 – 250 mm (custom to 500 mm) | Standard DIN sizes: 8, 10, 12.5, 16, 20, 25, 31.5... up to 250 mm |
| Inner Diameter (d) | 3.2 – 150 mm | Diameter ratio d/D typically between 0.45 and 0.55 |
| Thickness (t) | 0.2 – 30.0 mm | Group 1 (t < 1.25mm), Group 2 (1.25–6mm), Group 3 (> 6mm with contact flats) |
| Free Cone Height (h₀) | 0.5 – 50.0 mm | Free height ratio h₀/t dictates load curve progression |
| Single Disc Load | 5 kN – 300+ kN | Can be multiplied via parallel stacking combinations |
Mathematical Load Calculation (Almen-Laszlo Formulation)
The axial force F exerted by a standard DIN 2093 disc spring at deflection s is calculated via the classical Almen-Laszlo equation:
Almen-Laszlo Load Formula:
F(s) = [4E / (1 - μ²)] · (t⁴ / (K₁ · D²)) · (s / t) · [((h₀ / t) - (s / t)) · ((h₀ / t) - (s / (2t))) + 1]
Where: E = Young's Modulus (206 GPa for 50CrV4); μ = Poisson's ratio (0.3);
D = Outer Diameter; t = Thickness; h₀ = Cone height (free height minus thickness);
s = Working deflection; K₁ = Dimensionless geometry coefficient based on diameter ratio δ = D/d.
In practical machine design, engineers reference standardized DIN 2093 lookup tables rather than computing the equation manually. TOSTA provides complete CAD catalogs and verified calculation templates for all standard sizes.
Influence of the h₀/t Ratio on Load Curves
- h₀/t ≈ 0.4 (Linear Behavior): The spring rate remains virtually constant throughout the entire deflection stroke. Highly recommended for thermal gasket compensation and sliding bearing take-up where predictable proportional resistance is needed.
- h₀/t ≈ 0.75 (Degressive / Regressive Behavior): Spring stiffness decreases as deflection increases. This is the optimal selection for heavy bolted flange joints, maintaining steady bolt tension even when slight vibration or gasket creep occurs.
- h₀/t ≥ 1.414 (Horizontal Plateau / Snap-Through): The load-deflection curve exhibits an almost zero-stiffness plateau or negative spring rate past 75% deflection, used in specialized switchgear and release clutches.
Require DIN 2093 Standard Disc Springs?
TOSTA stocks all DIN 2093 standard sizes with immediate dispatch, 1-piece MOQ, and complete mill test certificates.