Wardle Ultra-precision Bearings

1. Auflage 2015
ISBN: 978-0-85709-218-2
Verlag: Elsevier Science & Techn.
Format: EPUB
Kopierschutz: 6 - ePub Watermark

E-Book, Englisch, 442 Seiten

Ultra-precision bearings can achieve extreme accuracy of rotation, making them ideal for use in numerous applications across a variety of fields, including hard disk drives, roundness measuring machines and optical scanners. Ultraprecision Bearings provides a detailed review of the different types of bearing and their properties, as well as an analysis of the factors that influence motion error, stiffness and damping. Following an introduction to basic principles of motion error, each chapter of the book is then devoted to the basic principles and properties of a specific type of bearing: ball, hydrodynamic, aerodynamic, hydrostatic and aerostatic. The book concludes with a comparison of these types of bearing and their applications. - Provides practical information relating to precision bearing design and application - Provides an insight into the basic mechanisms that influence precision bearing performance - Written by an experienced and well respected bearing specialist

Frank Wardle is Managing Director of UPM Ltd - a research and development company specialising in Ultra Precision equipment. He has more than 30 years of practical experience in bearing research, initially with the rolling bearing companies Ransom, Hoffman and Pollard (RHP) and SKF and later with the air bearing manufacturer Loadpoint Ltd. Throughout this period he was not only responsible for research into ways of improving bearing performance, but also for developing new commercial bearing designs and some of the machinery used for their manufacture and testing.

Autoren/Hrsg.

Wardle, F.

Leseproben

List of figures and tables
Figures 1.1 Micro-milled upstand – 15 µm wide 4 1.2 Ultra precision bearing system 6 1.3 Effect of (a) synchronous, and (b) asynchronous motion error on surface form 9 1.4 Notation and components of motion error produced by rotating bearings 10 1.5 Measurement of ball bearing motion error 11 1.6 Total motion error 12 1.7 (a) Synchronous motion error; and (b) asynchronous motion error 13 1.8 (a) Fundamental error motion; and (b) residual synchronous error motion 15 1.9 Displacement time history and frequency analysis 16 1.10 Hypothetical bearing load-deflection characteristics 19 1.11 Notation and coordinate system used to define static stiffness 20 1.12 Deflections produced by radial load applied to preloaded ball bearing 21 1.13 Hydrodynamic bearing subject to radial load 21 1.14 Notation and coordinate system for linear bearings 23 1.15 Types of damping associated with bearings 24 1.16 Dynamic response of a bearing-shaft system 26 1.17 Effect of damping ratio on magnification factor 27 1.18 FEA of machine tool modes of vibration 30 1.19 Thermal distortion of machining spindle 32 1.20 Thermal model of bearing 33 2.1 (a) Single-row radial ball bearing; and (b) angular contact ball bearing 38 2.2 Sections available on precision angular contact bearings of nominally 50 mm pitch circle diameter 40 2.3 Example of single-row radial ball bearing arrangements 41 2.4 Popular angular contact ball bearing arrangements: (a) face–face; (b) back–back; (c) triple; and (d) quadruple bearing sets 42 2.5 Spring preloaded angular contact bearing arrangements 43 2.6 Example of shaft geometry and roughness parameters 50 2.7 Example of housing geometry and roughness parameters 52 2.8 Geometrical parameters 54 2.9 Rolling speeds 57 2.10 Contact geometry 60 2.11 Loads and deflections for a single ball 64 2.12 Relative approach of inner and outer rings 66 2.13 Relative ring movements for spring loaded controlled alignment bearing subject to axial and radial loads 70 2.14 Axial load–deflection characteristics of 7006 angular contact ball bearing 70 2.15 Dependence of bearing stiffness on preload for a 7006 angular contact ball bearing 71 2.16 Comparison of spring and springbox preloaded bearing arrangements 72 2.17 The effect of mounting on the radial stiffness of a preloaded 7006 15-degree angular contact ball bearing 73 2.18 Spring preloaded angular contact bearing mounted in a linear bearing 73 2.19 Back–back angular contact bearing preloaded with spacers 75 2.20 Radial load–deflection relationships for 2007 spring preloaded and back–back mounted bearings subject to 50 N preload 75 2.21 Angular stiffness of spring preloaded and back–back mounted 7006 angular contact bearing 76 2.22 Effect of bearing speed on stiffness for a 7006 15-degree angular contact bearing subject to 200 N axial preload 77 2.23 Force equilibrium of ball in a high-speed bearing 78 2.24 Sources of damping associated with precision ball bearings 80 2.25 Model of ball–race contacts 82 2.26 Axial damping coefficient for preloaded 7006 15-degree angular contact bearing 85 2.27 Experimental and theoretical radial load deflection curves for preloaded 7210 angular contact bearing 86 2.28 Ball bearing with imperfections on ball, inner and outer ring surfaces 90 2.29 Relationship between dynamic force and displacement 91 2.30 Arrangement for measuring bearing vibration 96 2.31 Spectral analysis of outer raceway surface 97 2.32 Comparison of measured and theoretical axial acceleration spectra 98 2.33 Examples of the effect of axial preload on the low frequency vibration of a single-row radial ball bearing 100 2.34 Suggested minimum axial preload to prevent cage instability in grease lubricated single-row radial ball bearings 101 2.35 Ball load distribution in a radially loaded ball bearing 102 2.36 Variable compliance vibration produced by radially loaded bearing 103 2.37 Variable compliance produced by axially preloaded ball bearing 104 2.38 Dynamic component of variable compliance force due to misalignment 104 2.39 Lobing, waviness and roughness of rolling surfaces 106 2.40 Example of ball load variation due to 2-point lobing 107 2.41 Dynamic force produced by 2-point lobing in a preloaded ball bearing 108 2.42 Effect of one large ball on bearing motion error 109 2.43 Effect of random ball size variation on motion error 109 2.44 Example of axial dynamic force due to waviness 110 2.45 Example of radial dynamic force due to waviness 110 2.46 Surface roughness in relation to a ball–raceway...