Calcolatori di molle

Torsion spring calculator

Calculate the angular rate (per degree), maximum safe torque and maximum angle of torsion springs with legs.

Unità
mm
mm
mm
°
Risultato
Costante angolare0.0514 lbf·in/° [5.813 N·mm/°]
Coppia massima sicura9.56 lbf·in [1080 N·mm]
Angolo massimo sicuro186°
Indice della molla9.00
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Formula

M₃₆₀ = E·d⁴ / (10.8·D·Na)
k = M₃₆₀ / 360

M₃₆₀ is the torque for one full turn. Divided by 360 it becomes the angular rate per degree, the form the calculator displays.

Simboli

kangular rate (lbf·in/° or N·mm/°)
Eelastic modulus of the material (psi or MPa)
dwire diameter (in or mm)
Dmean coil diameter: OD − d (in or mm)
Nanumber of active coils
M₃₆₀torque per full turn (lbf·in or N·mm)

Esempio calcolato

Dati
Diametro del filo0.079 in [2.00 mm]
Diametro esterno0.787 in [20.00 mm]
Lunghezza del braccio1.181 in [30.00 mm]
Spire totali8
MaterialeAcciaio al carbonio (MW)
Risultato
Costante angolare0.0514 lbf·in/° [5.813 N·mm/°]
Coppia massima sicura9.56 lbf·in [1080 N·mm]
Angolo massimo sicuro186°

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

Torsion springs store energy through rotation. The angular rate depends on the material's elastic modulus and the coil geometry.

Set the leg length and angle and see the available torque.

Always load the spring in the direction that winds the coil tighter: it seats the coils on the arbor and allows higher working stresses.

Come misurare la molla

  1. Measure the wire diameter (d) on the body of the spring.
  2. Measure the outer diameter (OD) across the coils.
  3. Count the number of body coils.
  4. Measure the leg length from the body to the tip.
  5. Measure the free angle between the legs and note the wind direction (right or left hand). Torsion springs should be loaded in the direction that winds the coil tighter.

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 units is a torsion spring rate measured in?

Torque per angle: lbf·in per degree in imperial or N·mm per degree in metric. Catalogs also quote the torque per full turn (360 degrees).

Does the direction of rotation matter?

Yes. The spring should be loaded in the wind direction, closing the coil. Loading it the other way opens the coils and drastically reduces the allowable load.

What changes the rate of a torsion spring?

Wire diameter (fourth power), mean diameter, number of coils and the material's elastic modulus. More coils or a larger diameter make the spring softer.

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