Calcolatori di molle

Spring force calculator

Calculate the force (load) a compression spring exerts and the maximum safe load before the material yields.

Unità
mm
mm
mm
Risultato
Costante elastica37.793 lbf/in [6.62 N/mm]
Carico massimo sicuro37.104 lbf [165.04 N]
Freccia massima sicura0.982 in [24.94 mm]
Altezza a pacco0.689 in [17.50 mm]
Indice della molla9.00
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Formula

k = G·d⁴ / (8·D³·Na)
F = k·x

Simboli

kspring rate (N/mm or lbf/in)
Gshear modulus of the material (psi or MPa)
dwire diameter (in or mm)
Dmean coil diameter: OD − d (in or mm)
Nanumber of active coils
Fforce at deflection x (lbf or N)
xdeflection from free length (in or mm)

Esempio calcolato

Dati
Diametro del filo0.098 in [2.50 mm]
Diametro esterno0.984 in [25.00 mm]
Lunghezza libera2.362 in [60.00 mm]
Spire totali7
MaterialeTemprato in olio (OT)
Risultato
Costante elastica37.793 lbf/in [6.62 N/mm]
Carico massimo sicuro37.104 lbf [165.04 N]
Freccia massima sicura0.982 in [24.94 mm]

Calcolato dallo stesso motore del calcolatore sopra, con i valori iniziali del modulo.

Force is rate times deflection (F = k·x). Use the designer to simulate specific operating points and see the stress margin.

The calculator also reports solid height and maximum safe deflection, with the Wahl correction applied to the shear stress.

If you know the required force and travel instead, use the required rate calculator to find out which spring to look for.

Regolazione rapida: più o meno forza

Più forza
  • Filo più spesso
  • Diametro esterno minore
  • Meno spire attive
Meno forza
  • Filo più sottile
  • Diametro esterno maggiore
  • Più spire attive

Come misurare la molla

  1. Measure the wire diameter (d) with calipers or a micrometer, away from the ends.
  2. Measure the outer diameter (OD) across the coils. The mean diameter is OD minus d.
  3. Measure the free length (FL) with no load, end to end.
  4. Count the total number of coils. Closed and ground ends reduce the active coil count.
  5. Identify the end type: closed and ground, closed, double closed or open.

Moduli e densità dei materiali

MaterialeModulo di taglio GModulo elastico EDensità
Acciaio al carbonio (MW)11.5 × 10⁶ psi (79.3 GPa)29.5 × 10⁶ psi (203.4 GPa)7.85 g/cm³
Inox 302 (SS302)10.0 × 10⁶ psi (69.0 GPa)28.0 × 10⁶ psi (193.0 GPa)7.90 g/cm³
Inox 17-7 PH (SS177)11.0 × 10⁶ psi (75.8 GPa)29.4 × 10⁶ psi (203.0 GPa)7.81 g/cm³
Inox 316 (SS316)10.0 × 10⁶ psi (69.0 GPa)28.0 × 10⁶ psi (193.0 GPa)7.98 g/cm³
Temprato in olio (OT)11.2 × 10⁶ psi (77.2 GPa)29.5 × 10⁶ psi (203.4 GPa)7.85 g/cm³
Cromo-silicio (CS)11.2 × 10⁶ psi (77.2 GPa)29.5 × 10⁶ psi (203.4 GPa)7.85 g/cm³
Trafilato duro (HD)11.5 × 10⁶ psi (79.3 GPa)29.5 × 10⁶ psi (203.4 GPa)7.85 g/cm³
Bronzo fosforoso (PB)6.0 × 10⁶ psi (41.4 GPa)14.9 × 10⁶ psi (103.0 GPa)8.86 g/cm³
Rame berillio (BC)7.0 × 10⁶ psi (48.3 GPa)18.6 × 10⁶ psi (128.0 GPa)8.25 g/cm³
Cromo-vanadio (CV)11.2 × 10⁶ psi (77.2 GPa)29.5 × 10⁶ psi (203.4 GPa)7.85 g/cm³

Domande frequenti

What is the formula for spring force?

F = k·x (Hooke's law): force equals the spring rate times the deflection. A 45 lbf/in spring compressed 0.5 in exerts 22.5 lbf.

What limits the maximum load of a spring?

The shear stress in the wire, corrected by the Wahl factor, compared with the material's allowable stress. Exceeding it causes permanent set (the spring loses free length).

Does force stop growing at solid height?

No: at solid height the spring becomes a rigid tube and force rises abruptly. Running into solid damages the spring and the mechanism, so keep design clearance.

Progetta la molla e ricevi subito il preventivo

Apri il progettista 3D, regola le dimensioni e vedi i prezzi per quantità con disegno tecnico e analisi delle tensioni.

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