1. 364 書名： Essentials of Mechanical Engineering Design, 1/E 作者： Shigey Mischke Budynas 書號： MX0398

2. 365 7-1 Stress in Helical spring

3. 366 Spring index For most spring C is between 6 to 12 Shear stress correction factor

4. 367 Wahl factor Bergstrasser factor (preferred) Both factor can be used to replace the shear stress correction factor K s However, in this book use:

5. 368 Casrtigliano’s theory:

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7. 370 Forrys point out Square and ground end, the solid length is a=0.75 Set removal

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9. 372 For squared and ground end α=0.5 D

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18. 381 Usually takes ξ>0.15 Recommended design conditions: When design a high volume production Fom (figure of merit) Is used to compare the cost of production.

19. 382 From eq. 7-3 and Let

20. 383 Design strategy

21. 384 Design strategy

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26. 389 The spring exert a force about 3 lbf and to fit the space defined in figure

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32. 395 Natural frequency of spring place between two flat face Fundamental frequency For one end against a plate The weight of active part Fundamental critical frequency should be 15 to 20 times of the frequency of the external force

33. 396 Unpeened: Peened For example, given a unpeened spring with ultimate shear strength 211.5 kpsi. By Gerber:

34. 397 Torsional modulus of rupture is The mean force and amplitude The shear stress amplitude Mean stress:

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48. 411 Stress at point A Stress correction factor for curvature: The torsional stress at B

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50. 413 Free length Prefer range of tension:

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63. 426 In ex. 7-7 an estimate for the bending endurance limit from Table 7-8 would be

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65. 428 Describing the end location

66. 429 Bending stress Bending stress can be obtained from curved beam Bending eq.: Deflection and spring rate, let The angle subtended by the end deflection of the cantilever:

67. 430 For straight torsion end spring the strain energy in bending is Applying Castigliano’s theorem: The total angular deflection:

68. 431 Torque/turn Considering the friction The helix diameter The angular deflection Diameter clearance

69. 432 Static strength Fatigue strength Gewrber fatigue Safety factor

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76. 439 For a uniform-section cantilever spring has thev stress Flat triangular spring Width at base b=b 0 x/l

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