1. Muhannad Al_Waily_Machines Systems Design
Spring Design

2. Disk (Belleville) springs
Muhannad Al_Waily_Machines Systems Design
Types of Springs
Helical springs
Compression helical springs
Tension helical springs
Torsion helical springs
Leaf springs
Conical springs
Disk (Belleville) springs
Ring springs
Spiral springs
Torsion bear spring
Air springs
Liquid springs
Rubber springs

3. applications in machinery
Muhannad Al_Waily_Machines Systems Design
applications in machinery
Springs are used to control forces due to impact or shock loading and to control vibration.
Springs are employed to control motions and to apply forces to members.
Springs are used for storing energy, in clocks, switch-throwing devices, and starters.
Springs are employed to measure forces, as in scales.
Spring Rate
For springs in series the spring rates add reciprocally
The individual spring rates add directly

4. Muhannad Al_Waily_Machines Systems Design
Spring Materials
Shear strength

5. Muhannad Al_Waily_Machines Systems Design

6. Muhannad Al_Waily_Machines Systems Design

7. Muhannad Al_Waily_Machines Systems Design

8. Helical Spring Helical Compression Springs
Muhannad Al_Waily_Machines Systems Design
Helical Spring
Helical Compression Springs
The force ' P ' applied at each end at a distance ' R ' from the center of the wire produces a torsional moment
Stresses in Helical Compression Spring Coils
Torsional shear stress
Transverse Shear Stress
A curvature correction factor attributed to 'A.M'. Wahl results in the following
=3 and 12

9. Muhannad Al_Waily_Machines Systems Design

10. Spring Rate Deflection Castigliano's theorem
Muhannad Al_Waily_Machines Systems Design
Spring Rate
Deflection
Castigliano's theorem
The deflection due to torsional loading

11. End Conditions and Spring Length
Muhannad Al_Waily_Machines Systems Design
End Conditions and Spring Length

12. The torsional strengths of spring wire vary depending on the material
Muhannad Al_Waily_Machines Systems Design
The torsional strengths of spring wire vary depending on the material

13. Designing Helical Compression Springs for Static and Fatigue Loading
Muhannad Al_Waily_Machines Systems Design
Designing Helical Compression Springs for Static and Fatigue Loading
The safety factor for static loading
the dynamic safety factor
All spring-steel wire of ( > 10 mm) diameter exhibits a torsional endurance limit for infinite life

14. Helical Extension Springs
Muhannad Al_Waily_Machines Systems Design
Helical Extension Springs

15. Coil Preload in Extension Springs End Stresses in Extension Springs
Muhannad Al_Waily_Machines Systems Design
Coil Preload in Extension Springs
End Stresses in Extension Springs
The bending stress at point ' A '
The torsional stress at point ' B '
' C2 ' should be greater than ' 4 '

16. Helical Torsion Springs Deflection of Torsion Springs
Muhannad Al_Waily_Machines Systems Design
Helical Torsion Springs
equivalent number of coils
The number of active coils
' Nb ' is the number of coils in the spring body
Deflection of Torsion Springs
The factor ' 10.2 ' is usually increased to ' 10.8 ' to account for the friction between coils

17. Coil Stresses in Torsion Springs
Muhannad Al_Waily_Machines Systems Design
Coil Stresses in Torsion Springs
maximum compressive bending stress at the inside coil diameter
the tensile bending stress components at the outside coil diameter
The torsional-endurance limit data for helical compression springs be adapted for bending by using the von Mises relationship between torsion and tension loading

18. Muhannad Al_Waily_Machines Systems Design
Leaf Springs
The maximum moment occurs at ' x = L'

19. Belleville Spring Washers
Muhannad Al_Waily_Machines Systems Design
Belleville Spring Washers

20. Stresses in Belleville Washers
Muhannad Al_Waily_Machines Systems Design
Stresses in Belleville Washers

21. Load-Deflection Function for Belleville Washers
Muhannad Al_Waily_Machines Systems Design
Load-Deflection Function for Belleville Washers
The load at the flat position ( y = h )
Designing Belleville Springs