tailieunhanh - Ebook Mechanical engineering design (9th edition): Part 2

(BQ) Part 2 book "Mechanical engineering design" has contents: Mechanical springs, rolling contact bearings, lubrication and journal bearings, spur and helical gears, spur and helical gears, flexible mechanical elements, power transmission case study, statistical considerationsm,.and other contents. | 12/16/2009 7:14 pm Page 517 pinnacle 203:MHDQ196:bud29281:0073529281:bud29281_pagefiles: 1 0 Mechanical Springs Chapter Outline 10–1 Stresses in Helical Springs 10–2 The Curvature Effect 10–3 Deflection of Helical Springs 10–4 Compression Springs 10–5 Stability 10–6 Spring Materials 10–7 Helical Compression Spring Design for Static Service 10–8 Critical Frequency of Helical Springs 10–9 Fatigue Loading of Helical Compression Springs 518 519 520 520 522 523 528 534 536 10–10 Helical Compression Spring Design for Fatigue Loading 10–11 Extension Springs 10–12 Helical Coil Torsion Springs 10–13 Belleville Springs 10–14 Miscellaneous Springs 10–15 Summary 539 542 550 557 558 560 517 518 12/16/2009 7:14 pm Page 518 pinnacle 203:MHDQ196:bud29281:0073529281:bud29281_pagefiles: Mechanical Engineering Design When a designer wants rigidity, negligible deflection is an acceptable approximation as long as it does not compromise function. Flexibility is sometimes needed and is often provided by metal bodies with cleverly controlled geometry. These bodies can exhibit flexibility to the degree the designer seeks. Such flexibility can be linear or nonlinear in relating deflection to load. These devices allow controlled application of force or torque; the storing and release of energy can be another purpose. Flexibility allows temporary distortion for access and the immediate restoration of function. Because of machinery’s value to designers, springs have been intensively studied; moreover, they are mass-produced (and therefore low cost), and ingenious configurations have been found for a variety of desired applications. In this chapter we will discuss the more frequently used types of springs, their necessary parametric relationships, and their design. In general, springs may be classified as wire springs, flat springs, or specialshaped springs, and there are variations within these .