They were first proposed by the French inventor J. F. Belleville in 1867, hence the alternative name “Belleville spring.” Manufactured from high-strength sheet metal or forged blanks of uniform thickness, disc springs are cold- or hot-formed into a conical profile. Used singly or in stacks, they store, release, damp, preload, or isolate energy under axial loads. Because they deliver large forces in minimal deflection, offer tailorable non-linear characteristics, and combine compactness, low mass, and long fatigue life, disc springs have largely replaced traditional helical compression springs wherever “small yet powerful” springs are required. They are now indispensable in automobiles, machine tools, wind energy, valves, aerospace, ordnance, electronics, and many other fields.

1. Geometry and Classification

1.1 Basic Geometry

A single disc spring is a truncated cone with a central bore. Its key dimensions are outer diameter D, inner diameter d, thickness t, and free height H₀. Under an axial force F, the height reduces from H₀ to H, giving a deflection s = H₀ – H. The load–deflection relationship is non-linear and is described theoretically by the Almen–Laszlo formula:

F = (4E t⁴ s) / [(1 – μ²) D² K₁ (D/t)] · [K₄(H₀/t – s/t)(H₀/t – s/2t) + 1]

where E and μ are material constants, and K₁, K₄ are geometric correction factors.

1.2 Cross-Sectional Profiles

• Rectangular section: simplest to manufacture, most common, but produces higher stress concentrations.
• Trapezoidal section: variable thickness reduces peak stresses and increases fatigue life.
• Slotted section: 8–12 radial slots improve heat dissipation, lower noise, and allow larger deflection.
• Special profiles: rounded edges, flanged lips, spherical contact faces, or pre-stressed grooves for high-fatigue, high-temperature, vacuum, or self-lubricating applications.

1.3 Materials and Heat Treatment

Common materials: 60Si2MnA, 50CrV4, 30W4Cr2V, 17-7PH, Inconel 718, Ti-6Al-4V, etc.

Heat treatment: quenching + tempering (42–52 HRC) or precipitation hardening (Ni-base alloys). Surface treatments include shot peening, phosphating, MoS₂ coating, or DACROMET to enhance fatigue strength and corrosion resistance.

1.4 Stacking Methods

Single discs provide limited deflection; therefore, multiple discs are stacked:

• Parallel (nested) stack: n identical discs in the same orientation multiply the load by n and increase stiffness—used for high load, small deflection.
• Series (alternating) stack: m discs alternately inverted multiply deflection by m and reduce stiffness—used for large deflection, low load.
• Mixed stacks: series–parallel combinations or stacks with varying thicknesses and numbers tailor almost any desired load–deflection curve.

2. Operating Principle and Mechanical Characteristics

2.1 Non-Linearity

Disc springs exhibit high initial stiffness that drops sharply near the flattened position, creating a “hard-to-soft” curve that absorbs impact energy efficiently. By adjusting the H₀/t ratio, increasing, decreasing, or nearly constant-force characteristics can be designed.

2.2 High Energy Density

For the same outer diameter, disc springs achieve 5–10× the energy density of helical compression springs while occupying only 1/3 to 1/5 of the axial space. They are therefore essential in high-speed presses, gun recoil mechanisms, automotive clutches, and wind-turbine yaw brakes where space is extremely limited.

2.3 Frictional Damping

In multi-disc stacks, inter-disc sliding generates Coulomb damping, providing superior vibration absorption compared with helical springs. Applications include machine-tool anti-chatter devices, pipe-support vibration dampers, and elevator safety-gear buffers.

3. Principal Application Fields

3.1 Automotive

• Diaphragm clutch springs: single disc replaces dozens of helical springs, enabling compact, lightweight designs with low pedal effort.
• Wet dual-clutch packs: trapezoidal stacks supply 30–100 kN of precisely controlled clamp load for torques above 500 N·m.
• Brake-caliper return springs: stainless discs guarantee >1 million retraction cycles without failure.

3.2 Machine Tools and Heavy Machinery

• Press overload protection: when punching force exceeds the set value, the disc stack flattens instantly and triggers a limit switch to cut power.
• High-speed press vibration isolation: a 20-disc stack attenuates 200 kN impact force by 90 %, protecting the foundation and dies.

3.3 Valves and Piping

• Safety valves: disc stacks act as sensing elements, causing the valve to pop open when pressure exceeds the set point.
• High-temperature gate-valve seal compensation: Inconel disc stacks maintain constant sealing pressure at 550 °C and prevent leakage.

3.4 Aerospace

• Aircraft landing-gear shock absorbers: titanium disc stacks weigh only 40 % of equivalent steel helical springs and operate from –55 °C to 150 °C.
• Satellite solar-array hinge locks: disc springs deliver 10 N·m constant torque to ensure reliable deployment and locking.

3.5 Wind Energy and Renewable Power

• Wind-turbine yaw brakes: each turbine uses 24 large-diameter disc stacks producing 400 kN braking torque to withstand 70 m/s gusts.
• High-speed shaft brakes: on grid loss, disc stacks press brake pads to stop the rotor within 2 s.

3.6 Electronics and Precision Machinery

• Smartphone camera OIS: φ3 mm stainless disc springs provide 0.5 N preload for 1 µm positioning accuracy.
• Hard-disk head loading: two disc springs in series supply 5 N load within 2 mm height for stable read/write operation.

4. Design Guidelines and Selection Procedure

• Define load and deflection requirements: F_max, s_max, allowable envelope D × H.
• Select material according to temperature, corrosion, and fatigue-life demands.
• Preliminary geometry: use DIN 2093 or GB/T 1972 charts/software to propose D, d, t, H₀.
• Stress check: ensure σ_max ≤ 0.9 σ_y; verify fatigue life using DIN 2093 curves.
• Stack design: if a single disc is insufficient, combine nested and inverted stacks; consider inter-disc friction μ = 0.02–0.05.
• Validation: perform 1.2 × 10⁶ cycles on a test rig to check permanent set and crack initiation.

5. Common Failure Modes and Countermeasures

• Fatigue fracture: originates at the point of maximum tensile stress (upper surface of inner edge). Countered by shot peening, lowering H₀/t, or adopting trapezoidal sections.
• Snap-through buckling: occurs at high aspect ratios (H₀/t > 1.5). Use guide sleeves or spacer rings.
• Fretting wear: micro-slip between stacked discs produces debris. Apply MoS₂ coating or dry-film lubrication.
• Stress relaxation: manifests above 200 °C. Switch to 30W4Cr2V or Ni-base alloys.

6. Brief Manufacturing Process

Blanking → Piercing → Cold forming → Stress-relief annealing → Quenching → Tempering → Presetting → Shot peening → Face grinding → Magnetic-particle inspection → Corrosion protection → Final inspection. For large sizes (>300 mm) or heavy gauges (>16 mm), hot forming followed by secondary sizing is required to ensure dimensional accuracy and consistent performance.

7. Development Trends

• Digital design: AI-based fatigue-life prediction and multi-objective optimization (weight–stiffness–life) software is now commercially available.
• Advanced materials: high-nitrogen stainless steels, Co-Ni superalloys, and carbon-fiber-reinforced composite disc springs are in experimental stages.
• Miniaturization: MEMS disc springs (<1 mm) for micro-robots and medical catheter tip actuators.
• Smart monitoring: embedding fiber Bragg gratings inside disc stacks enables real-time load and temperature monitoring for Industry 4.0 condition-based maintenance.

8. Conclusion

With their unique ability to “achieve more with less,” disc springs have become irreplaceable core components in modern power transmission, vibration control, energy storage, and sealing systems. As materials science, computational mechanics, and intelligent manufacturing continue to advance, disc springs will evolve toward higher strength, lighter weight, and smarter functionality, playing an increasingly vital role in new-energy vehicles, commercial spaceflight, deep-sea equipment, humanoid robots, and other cutting-edge fields.

Handan Guocheng Trading Co., Ltd

www.handanguocheng.com