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Sổ tay tiêu chuẩn thiết kế máy P33

Tham khảo tài liệu 'sổ tay tiêu chuẩn thiết kế máy p33', kỹ thuật - công nghệ, cơ khí - chế tạo máy phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | CHAPTER 28 JOURNAL BEARINGS Theo G. Keith Jr. Ph.D. Professor and Chairman of Mechanical Engineering University of Toledo Toledo Ohio 28.1 INTRODUCTION 28.3 28.2 BEARING AND JOURNAL CONFIGURATIONS 28.4 28.3 BEARING MATERIALS AND SELECTION CRITERIA 28.7 28.4 PRESSURE EQUATION FOR A LUBRICATING FILM 28.13 28.5 JOURNAL BEARING PERFORMANCE 28.16 28.6 LIQUID-LUBRICATED JOURNAL BEARINGS 28.20 28.7 GAS-LUBRICATED JOURNAL BEARINGS 28.43 28.8 HYDROSTATIC JOURNAL BEARING DESIGN 28.52 REFERENCES 28.57 LIST OF SYMBOLS a Axial-flow land width ar Pad load coefficient A Area b Circumferential-flow land width C Clearance C Specific heat D Diameter e Eccentricity f Coefficient of friction Fj Friction on journal h Film thickness h0 Minimum film thickness H Dimensionless film thickness J Mechanical equivalent of heat k Permeability L Bearing width M Rotor mass at bearing Mj Frictional torque on journal 28.1 28.2 STANDARD HANDBOOK OF MACHINE DESIGN n Number of pads or recesses N Revolutions per unit time p Pressure pa Ambient pressure pQ Short-bearing pressure pr Recess pressure ps Supply pressure p Long-bearing pressure p Dimensionless pressure P Unit loading q Volume flow rate per unit length qf Flow factor Q Volume flow rate Qs Side leakage flow rate R Radius of journal Rb Radius of bearing R C 5 Stiffness S Sommerfeld number iN P RIC 2 t Time tp Thickness of porous liner T Temperature u v iv Velocity in x y z directions respectively U Velocity of journal W Load Load component directed along line of centers WT Load component normal to line of centers x y z Rectangular coordinates X Dimensionless minimum-film-thickness parameter 0 R P 27tNp 1 2 Y Dimensionless frictional torque parameter M W7 P 27tVp 1 2 a Porous material slip coefficient P Included angle of partial bearing porous bearing parameter Pi Angle from line of centers to leading edge of partial bearing y Circumferential-flow parameter e Eccentricity ratio e c Ç Dimensionless axial dimension z L 2 0 Angular position .