How to Use the Calculator
- Enter the wire diameter (d) of your torsion spring in millimeters (mm).
- Enter the mean diameter (D) of your torsion spring in millimeters (mm).
- Enter the shear modulus (G) of the material in MPa (Megapascals).
- Enter the spring angle (θ) in degrees, which is the angle through which the spring is twisted.
- Click the "Calculate" button to compute the torque and polar moment of inertia.
- Click "Reset" to clear all inputs and start over.
Understanding the Formula
The calculator uses the following formula to calculate the torque (T) of a torsion spring:
T = (G × J × θ) / (2 × π × D)
Where:
- T = Torque (N·mm) - The rotational force applied to the spring
- G = Shear Modulus (MPa) - A material property that indicates its resistance to shear deformation
- J = Polar Moment of Inertia (mm⁴) - A geometric property of the wire cross-section
- θ = Spring Angle (degrees) - The angle of deflection from the neutral position
- D = Mean Diameter (mm) - The average diameter of the spring
Applications
Torsion springs are used in various applications including:
- Dashboard instruments (speedometers, gauges)
- Watches and clocks
- Valves and actuators
- Office machinery
- Automotive components
Important Notes
- Ensure all measurements are in consistent units (mm for dimensions, MPa for shear modulus)
- The calculated torque is for the current spring angle entered
- This calculator assumes a linear spring behavior and does not account for spring fatigue or material non-linearity
- For real-world applications, always refer to manufacturer specifications and safety factors