SPRING DESIGN

Monday, 09 December 2013 | Por Muelles Crom | Technical design

Basic and elementary in the calculation and design of springs.

BASIC PRINCIPLES

There are three basic principles in spring design

The heavier the wire, the stronger the spring
The smaller the coil, the stronger the spring
The more active coils, the less load you will have to apply in order to get it to move a certain distance.

ENGINEERING DEPARTMENT

& PROCESS OF MUELLES CROM

Compression Spring Software V3000 Copyright 2.013

Muelles CROM Design engineering + Compression Spring Software V15.64 #0410

Compression spring No.: 2098-4x32x120

Application : Hans ecker Maschinenelemente, Hanser Verlag

EN 10270-1 SH spring steel wire pat.drawn
Manufacturing : cold-coiled
Spring ends : lined-up and ground
Stress : static
Surface : drawn
Manufacturing compensation : no comment
adm.deviation De,Di,Dm : to DIN 2095 Quality Class 2
adm.deviation L0 : to DIN 2095 Quality Class 2
adm.deviation F1, F2 : to DIN 2095 Quality Class 2
adm.deviation e1, e2 : to DIN 2095 Quality Class 2
adm.deviation d : to DIN 2076 C

modulus of elasticity	E	N/mm²	206000
shear modulus	G	N/mm²	82000
density	rho	kg/dm^3	7.85
tensile strength	Rm	N/mm²	1788
adm.shear stress	tauz	N/mm²	1001
operating temperature	theta	°C	20
shear-modulus at working temperat.	G 20	N/mm²	82000

MAIN DIMENSIONS

wire diameter	d	mm	4 +/- 0.025
inside diameter	Di	mm	28
mean coil diameter	Dm	mm	32
outside diameter	De	mm	36 ± 0.5
nos of coils	n(if)		8.5
inactive end coils lower side			1
inactive end coils upper side			1
Total number of coils	nt		10.5

SPRING LENGTHS

free length	L0	mm	120 ± 2.29
spring length at load F1	L1	mm	120
spring length at load F2	L2	mm	48.93
usable spring length	Ln	mm	48.93
Solid length of spring	Lc	mm	42.26 -0.262

SPRING LOAD

spring load at L1	F1	N	0 ± 21.6
spring load at L2	F2	N	669.5 ± 31.6
spring load at Ln	Fn	N	669.6
spring load at Lc	Fc th	N	732.4

SPRING TRAVELS

stroke	sh	mm	71.07
spring travel	s1	mm	0.00
spring travel	s2	mm	71.07
usable spring travel	sn	mm	71.07
spring travel to Lc	sc	mm	77.74
Excursion until Buckling	sk	mm	27.14

TENSIONS

shear stress at F1	tau 1	N/mm²	0
shear stress at F2	tau 2	N/mm²	852
shear stress at Fn	tau n	N/mm²	853
shear stress at Fc th.	tau c	N/mm²	932
stress coefficient	k		1.172
corrected shear stress at F1	tau k1	N/mm²	0
corrected shear stress at F2	tau k2	N/mm²	999
adm. shear stress	tau z	N/mm²	1001

Bearing Application Coefficient	nue		1
Deviation of Surface Line	e1	mm	6
Deviation of Parallelism	e2	mm	1.08
spring rate	R	N/mm	9.421
natural frequency	fe	1/s	167.2
Increase in Coil Diameter at Lc	deltaDe	mm	0.436
Minimum clearance of active coils	Sa	mm	6.66
Actual clearance of active coils	sc-s2	mm	6.67
coiling ratio	w		8
Gradient ratio	tan alfa		0.13
Gradient	m	mm	13.65
Gradient ratio	Dm/m		2.34
Lean grade	lambda		3.75
spring energy between s1 and s2	W12	Nmm	23792
weight of the spring	m	g	104.1
wire length	L	mm	1056
pressure	R/D	N/mm²	0.294
Max.diameter of bedding mandrel	Ddmax	mm	27.48
Minimum diameter of bore	Dhmin	mm	36.96