Spring Design Table 13. Formulas for Torsion Springs Springs made from round wire Machinery's Handbook, 31st Edition
334
Springs made from square wire
Feature
Formula a, b
. S T 1018 b
S T 6 b
3
3
d = Wire diameter, Inches
EF TND 4000 4 °
EF TND 2375 4 °
d T 6 3
. d T 1018 3
S b = Stress, bending pounds per square inch
EdF
EdF
°
°
392
392
ND
ND
EdF 392 b
EdF 392 b
°
°
S D
S D
N = Active Coils
4 °
4 °
Ed F
Ed F
2375
4000
TD
TD
Ed S ND 392 b Ed TND 4000 4
Ed S ND 392 b Ed TND 2375 4
F ° = Deflection
3
3
. S d 00982 b
. S d 01666 b
T = Torque Inch lbs. (Also = P 3 R )
4 °
4 °
Ed F
Ed F
4000
2375
ND
ND
I D 1 = Inside Diameter After Deflection, Inches
360 free + °
360 free + °
N ID ^
N ID ^
h
h
N F
N F
a Where two formulas are given for one feature, the designer should use the one found to be appropriate for the given design. The end result from either of any two formulas is the same. b The symbol notation is given on page 304 . Design Procedure: Torsion spring designs require more effort than other kinds because consideration has to be given to more details, such as the proper size of a supporting rod, reduction of the inside diameter, increase in length, deflection of arms, allowance for fric tion, and method of testing. Example: What music wire diameter and how many coils are required for the torsion spring shown in Fig. 24, which is to withstand at least 1000 cycles? Determine the cor rected stress and the reduced inside diameter after deflection.
Copyright 2020, Industrial Press, Inc.
ebooks.industrialpress.com
Made with FlippingBook - Share PDF online