Bearing Design in Machinery: Engineering Tribology and Lubrication

by Harnoy; Avraham

• ISBN13: 9780824707033
• ISBN10: 0824707036
• Edition: 1st
• Format: Hardcover
• Copyright: 2002-09-25
• Publisher: CRC Press

Summary

Covering the fundamental principles of bearing selection, design, and tribology, this book discusses basic physical principles of bearing selection, lubrication, design computations, advanced bearings materials, arrangement, housing, and seals, as well as recent developments in bearings for high-speed aircraft engines. The author explores unique solutions to challenging design problems and presents rare case studies, such as hydrodynamic and rolling-element bearings in series and adjustable hydrostatic pads for large bearings. He focuses on the design considerations and calculations specific to hydrodynamic journal bearings, hydrostatic bearings, and rolling element bearings.

Author Biography

Avraham Harnoy is Professor and Director of the Bearings and Lubrications Laboratory in the Mechanical Engineering Department, New Jersey Institute of Technology, Newark.

Table of Contents

Preface	v
Symbols	xvii
Classification and Selection of Bearings	1	(32)
Introduction	1	(4)
Dry and Boundary Lubrication Bearings	5	(1)
Hydrodynamic Bearing	6	(3)
Hydrostatic Bearing	9	(3)
Magnetic Bearing	12	(2)
Rolling Element Bearings	14	(3)
Selection Criteria	17	(2)
Bearings for Precision Applications	19	(1)
Noncontact Bearings for Precision Application	20	(1)
Bearing Subjected to Frequent Starts and Stops	21	(1)
Example Problems	22	(11)
Lubricant Viscosity	33	(14)
Introduction	33	(1)
Simple Shear Flow	34	(2)
Boundary Conditions of Flow	36	(1)
Viscosity Units	37	(1)
Viscosity--Temperature Curves	38	(2)
Viscosity Index	40	(1)
Viscosity as a Function of Pressure	41	(2)
Viscosity as a Function of Shear Rate	43	(1)
Viscoelastic Lubricants	43	(4)
Fundamental Properties of Lubricants	47	(20)
Introduction	47	(1)
Crude Oils	48	(1)
Base Oil Components	49	(1)
Synthetic Oils	50	(6)
Greases	56	(2)
Additives to Lubricants	58	(9)
Principles of Hydrodynamic Lubrication	67	(27)
Introduction	67	(2)
Assumptions of Hydrodynamic Lubrication Theory	69	(3)
Hydrodynamic Long Bearing	72	(1)
Differential Equation of Fluid Motion	72	(2)
Flow in a Long Bearing	74	(5)
Pressure Wave	79	(2)
Plane-Slider Load Capacity	81	(1)
Viscous Friction Force in a Plane-Slider	81	(1)
Flow Between Two Parallel Plates	82	(2)
Fluid-Film Between a Cylinder and Flat Plate	84	(2)
Solution in Dimensionless Terms	86	(8)
Basic Hydrodynamic Equations	94	(24)
Navier--Stokes Equations	94	(3)
Reynolds Hydrodynamic Lubrication Equation	97	(6)
Wide Plane-Slider	103	(1)
Fluid Film Between a Flat Plate and a Cylinder	104	(1)
Transition to Turbulence	105	(5)
Cylindrical Coordinates	110	(1)
Squeeze-Film Flow	111	(7)
Long Hydrodynamic Journal Bearing	118	(29)
Introduction	118	(2)
Reynolds Equation for a Journal Bearing	120	(1)
Journal Bearing with Rotating Sleeve	121	(1)
Combined Rolling and Sliding	122	(3)
Pressure Wave in a Long Journal Bearing	125	(2)
Sommerfeld Solution of the Pressure Wave	127	(2)
Journal Bearing Load Capacity	129	(2)
Load Capacity Based on Sommerfeld Conditions	131	(1)
Friction in a Long Journal Bearing	132	(2)
Power Loss on Viscous Friction	134	(1)
Sommerfeld Number	134	(1)
Practical Pressure Boundary Conditions	135	(12)
Short Journal Bearings	147	(14)
Introduction	147	(2)
Shor-Bearing Analysis	149	(4)
Flow in the Axial Direction	153	(1)
Sommerfeld Number of a Short Bearing	153	(1)
Viscous Friction	154	(1)
Journal Bearing Stiffness	155	(6)
Design Charts for Finite-Length Journal Bearings	161	(35)
Introduction	161	(1)
Design Procedure	162	(1)
Minimum Film Thickness	163	(1)
Raimondi and Boyd Charts and Tables	164	(17)
Fluid Film Temperature	181	(7)
Peak Temperature in Large, Heavily Loaded Bearings	188	(2)
Design Based on Experimental Curves	190	(6)
Practical Applications of Journal Bearings	196	(16)
Introduction	196	(1)
Hydrodynamic Bearing Whirl	197	(1)
Elliptical Bearings	198	(1)
Three-Lobe Bearings	199	(1)
Pivoted-Pad Journal Bearing	200	(2)
Bearings Made of Compliant Materials	202	(1)
Foil Bearings	203	(1)
Analysis of a Foil Bearing	204	(3)
Foil Bearings in High-Speed Turbines	207	(2)
Design Example of a Compliant Bearing	209	(3)
Hydrostatic Bearings	212	(55)
Introduction	212	(2)
Hydrostatic Circular Pads	214	(1)
Radial Pressure Distribution and Load Capacity	214	(4)
Power Losses in the Hydrostatic Pad	218	(1)
Optimization for Minimum Power Loss	219	(3)
Long Rectangular Hydrostatic Bearings	222	(1)
Multidirectional Hydrostatic Support	223	(3)
Hydrostatic Pad Stiffness for Constant Flow-Rate	226	(7)
Constant-Pressure-Supply Pads with Restrictors	233	(2)
Analysis of Stiffness for a Constant Pressure Supply	235	(8)
Journal Bearing Cross-Stiffness	243	(1)
Applications	244	(1)
Hydraulic Pumps	244	(4)
Gear Pump Characteristics	248	(4)
Flow Dividers	252	(1)
Case Study: Hydrostatic Shoe Pads in Large Rotary Mills	252	(15)
Bearing Materials	267	(41)
Fundamental Principles of Tribology	267	(6)
Wear Mechanisms	273	(2)
Selection of Bearing Materials	275	(4)
Metal Bearings	279	(4)
Nonmetal Bearing Materials	283	(25)
Rolling Element Bearings	308	(70)
Introduction	308	(6)
Classification of Rolling-Element Bearings	314	(9)
Hertz Contact Stresses in Rolling Bearings	323	(1)
Theoretical Line Contact	324	(7)
Ellipsoidal Contact Area in Ball Bearings	331	(9)
Rolling-Element Speed	340	(2)
Elastohydrodynamic Lubrication in Rolling Bearings	342	(3)
Elastohydrodynamic Lubrication of a Line Contact	345	(6)
Elastohydrodynamic Lubrication of Ball Bearings	351	(10)
Force Components in an Angular Contact Bearing	361	(17)
Selection and Design of Rolling Bearings	378	(124)
Introduction	378	(12)
Fatigue Life Calculations	390	(5)
Bearing Operating Temperature	395	(4)
Rolling Bearing Lubrication	399	(12)
Bearing Precision	411	(3)
Internal Clearance of Rolling Bearings	414	(2)
Vibrations and Noise in Rolling Bearings	416	(2)
Shaft and Housing Fits	418	(11)
Stress and Deformation Due to Tight Fits	429	(7)
Bearing Mounting Arrangements	436	(4)
Adjustable Bearing Arrangement	440	(7)
Examples of Bearing Arrangements in Machinery	447	(11)
Selection of Oil Versus Grease	458	(2)
Grease Lubrication	460	(7)
Grease Life	467	(4)
Liquid Lubrication Systems	471	(7)
High-Temperature Applications	478	(1)
Speed Limit of Standard Bearings	479	(2)
Materials for Rolling Bearings	481	(3)
Processes for Manufacturing High-Purity Steel	484	(1)
Ceramic Materials for Rolling Bearings	485	(5)
Rolling Bearing Cages	490	(1)
Bearing Seals	490	(8)
Mechanical Seals	498	(4)
Testing of Friction and Wear	502	(19)
Introduction	502	(1)
Testing Machines for Dry and Boundary Lubrication	503	(2)
Friction Testing Under High-Frequency Oscillations	505	(4)
Measurement of Journal Bearing Friction	509	(2)
Testing of Dynamic Friction	511	(1)
Friction-Testing Machine with a Hydrostatic Pad	512	(2)
Four-Bearings Measurement Apparatus	514	(3)
Apparatus for Measuring Friction in Linear Motion	517	(4)
Hydrodynamic Bearings Under Dynamic Conditions	521	(10)
Introduction	521	(1)
Analysis of Short Bearings Under Dynamic Conditions	522	(4)
Journal Center Trajectory	526	(1)
Solution of Journal Motion by Finite-Difference Method	526	(5)
Friction Characteristics	531	(9)
Introduction	531	(1)
Friction in Hydrodynamic and Mixed Lubrication	532	(5)
Friction of Plastic Against Metal	537	(1)
Dynamic Friction	537	(3)
Modeling Dynamic Friction	540	(16)
Introduction	540	(2)
Dynamic Friction Model for Journal Bearings	542	(1)
Development of the Model	543	(3)
Modeling Friction at Steady Velocity	546	(2)
Modeling Dynamic Friction	548	(2)
Comparison of Model Simulations and Experiments	550	(6)
Case Study: Composite Bearing---Rolling Element and Fluid Film in Series	556	(26)
Introduction	556	(2)
Composite-Bearing Designs	558	(5)
Previous Research in Composite Bearings	563	(1)
Composite Bearing with Centrifugal Mechanism	564	(4)
Performance Under Dynamic Conditions	568	(8)
Thermal Effects	576	(6)
Non-Newtonian Viscoelastic Effects	582	(14)
Introduction	582	(2)
Viscoelastic Fluid Models	584	(2)
Analysis of Viscoelastic Fluid Flow	586	(4)
Pressure Wave in a Journal Bearing	590	(2)
Squeeze-Film Flow	592	(4)
Orthopedic Joint Implants	596	(9)
Introduction	596	(2)
Artificial Hip Joint as a Bearing	598	(1)
History of the Hip Replacement Joint	599	(2)
Materials for Joint Implants	601	(1)
Dynamic Friction	602	(3)
Appendix A Units and Definitions of Material Properties	605	(4)
Appendix B Numerical Integration	609	(6)
Bibliography	615	(10)
Index	625