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Sổ tay tiêu chuẩn thiết kế máy P32

Tham khảo tài liệu 'sổ tay tiêu chuẩn thiết kế máy p32', kỹ thuật - công nghệ, cơ khí - chế tạo máy phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | CHAPTER 27 ROLLING-CONTACT BEARINGS Charles R. Mischke Ph.D. P.E. Professor Emeritus of Mechanical Engineering Iowa State University Ames Iowa 27.1 INTRODUCTION 27.2 27.2 LOAD-LIFE RELATION FOR CONSTANT RELIABILITY 27.7 27.3 SURVIVAL RELATION AT STEADY LOAD 27.8 27.4 RELATING LOAD LIFE AND RELIABILITY GOAL 27.9 27.5 COMBINED RADIAL AND THRUST LOADINGS I 27.12 27.6 APPLICATION FACTORS 127.13 27.7 VARIABLE LOADING 27.13 27.8 MISALIGNMENT I 27.16 REFERENCES 27.17 GLOSSARY OF SYMBOLS a Exponents a 3 for ball bearings a for roller bearings AF Application factor b Weibull shape parameter Cs Static load rating Clo Basic load rating or basic dynamic load rating f Fraction F Load Fa Axial load Feq Equivalent radial load Fi th equivalent radial load Fr Radial load Integral L Life measure r or h Ld Desired or design life measure Lr Rating life measure Ljo Life measure exceeded by 90 percent of bearings tested 27.1 27.2 STANDARD HANDBOOK OF MACHINE DESIGN n Design factor nD Desired or design rotative speed r min n Application or design factor at ith level nR Rating rotative speed r min R Reliability V Rotation factor inner ring rotations V 1 outer ring V 1.20 x Life measure in Weibull survival equation Xo Weibull guaranteed life parameter X Radial factor for equivalent load prediction Y Thrust factor for equivalent load prediction 0 Weibull characteristic life parameter rotation angle Period of cyclic variation rad 27.1 INTRODUCTION Figures 27.1 to 27.12 illustrate something of the terminology and the wide variety of rolling-contact bearings available to the designer. Catalogs and engineering manuals can be obtained from bearing manufacturers and these are very comprehensive and of excellent quality. In addition most manufacturers are anxious to advise designers on specific applications. For this reason the material in this chapter is concerned mostly with providing the designer an independent viewpoint. FIGURE 27.1 Photograph of a deep-groove precision ball bearing with metal