Ultra-precision Bearings (eBook)

F Wardle (Autor)

eBook Download: PDF | EPUB

2015 | 1. Auflage
442 Seiten
Elsevier Science (Verlag)
978-0-85709-218-2 (ISBN)

Infos

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.

Textauszug

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...

Produkt-Details

• Erscheint lt. Verlag: 10.2.2015
• Sprache: englisch
• Themenwelt: Technik ► Bauwesen
• Themenwelt: Technik ► Maschinenbau
• Themenwelt: Weitere Fachgebiete ► Handwerk
• ISBN-10: 0-85709-218-9 / 0857092189
• ISBN-13: 978-0-85709-218-2 / 9780857092182