List of symbols
| Symbol | Name of the symbol | Unit |
|---|---|---|
| $C$ | spring index | $\mathrm{ }$ |
| $D$ | mean coil diameter | $\mathrm{mm}$ |
| $D$ | spring outer diameter | $\mathrm{mm}$ |
| $D_0$ | mean coil diameter (vertex) | $\mathrm{mm}$ |
| $D_0$ | spring inner diameter | $\mathrm{mm}$ |
| $D_1$ | mean coil diameter (base) | $\mathrm{mm}$ |
| $E$ | modulus of elasticity | $\mathrm{GPa}$ |
| $E_p$ | energy stored | $\mathrm{J}$ |
| $F$ | force | $\mathrm{N}$ |
| $G$ | shear modulus | $\mathrm{GPa}$ |
| $K_W$ | wahl factor | $\mathrm{ }$ |
| $L$ | effective spring length | $\mathrm{mm}$ |
| $M$ | applied torque moment | $\mathrm{Nm}$ |
| $S_F$ | safety factor | $\mathrm{ }$ |
| $S_y$ | the minimum yield strength | $\mathrm{MPa}$ |
| $d$ | diameter of the spring wire | $\mathrm{mm}$ |
| $f$ | spring deflection | $\mathrm{mm}$ |
| $k$ | spring stiffness | $\mathrm{N/m}$ |
| $n$ | number of active coils | $\mathrm{ }$ |
| $r$ | spring length | $\mathrm{mm}$ |
| $δ$ | spring thickness | $\mathrm{mm}$ |
| $σ$ | tensile stress | $\mathrm{MPa}$ |
| $σ_B$ | bending stress | $\mathrm{MPa}$ |
| $σ_{adm}$ | material admissible stress | $\mathrm{MPa}$ |
| $τ_S$ | shear stress | $\mathrm{MPa}$ |
| $τ_{adm}$ | shear admissible stress | $\mathrm{MPa}$ |
| $φ$ | spring angular deflection | $\mathrm{°}$ |