Frist, you need spring constant K
this k value you can for k=(G*d^4/(8*Dav^3*Na)) , this k unit= (kgf/mm)
define: G=use material module often use G ex. SUS304=7300 kgf/mm^2
d=wire diameter
Dav=average diameter , Dav=(Do+Di)/2=Di+d=Do-d
Na=use spring active of coils
F=k*X this K=spring constant
X=deformed position
Assume: Na=5 coils ,SUS304 G=7300 kgf/mm^2 ,this Na value and material you must to decide
you condition free lenght=8mm, wire diameter=0.2mm ,inside diameter=2.4mm ,this compression lenght on 5mm
so,K=(G*d^4/(8*Dav^3*Na)) =((7300*0.2^4)/(8*2.6^3*5))= A ,youself calculate with value
F=A*(8-5)=B this B value you think about data |