Spring Mean Coil Diameter

Written by Jerry Ratzlaff on . Posted in Fastener

spring compression 6Spring Mean Coil Diameter formula

\(\large{ D =  \left(  \frac{G \; d^4}{8 \; k_s \ n_a } \right)^{ \frac{1}{3} } }\)

\(\large{ D = D_o - d  }\)

\(\large{ D = D_i + d  }\)

Where:

\(\large{ D }\) = mean coil diameter

\(\large{ D_i }\) = inner diameter

\(\large{ D_o }\) = outer diameter

\(\large{ n_a }\) = number of active coils

\(\large{ k_s }\) = spring constant

\(\large{ G }\) = shear modulus of material

\(\large{ d }\) = wire diameter

Solve for:

\(\large{ D_i = D_o - 2 \; d  }\)

\(\large{ D_o = D_i + 2 \; d  }\)

 

Tags: Equations for Spring