[...]... 10 .4 Reducing the T.E 10 .5 Permissible T.E levels 10 .6 Frequency changing 10 .7 Damping 10 .8 Production control options References 16 7 16 7 16 9 17 1 17 4 17 5 17 8 17 9 18 1 18 3 11 Lightly Loaded Gears 11 .1 Measurement problems 11 .2 Effects and identification 11 .3 Simple predictions 11 .4 Possible changes 11 .5 Anti-backlash gears 11 .6 Modelling rattle Reference 18 5 18 5 18 7 18 9 19 2 19 3 19 4 200 12 Planetary and. .. of measurement 7.9 Worms and wheels and spiral bevels 7 .10 Practical problems 7 .11 Comparisons References 93 93 95 96 99 10 3 10 4 10 6 11 0 11 2 11 3 11 7 11 9 8 Recording and Storage 8 .1 Is recording required? 8.2 Digital v analog 8.3 Current PC limits 8.4 Form of results 8.5 Aliasing and 8.6 Information compression 8.7 Archive information References 12 1 12 1 12 2 12 3 12 4 12 7 13 2 13 6 13 7 filters Contents xi... Techniques 9 .1 Types of noise and irritation 9.2 Problem identification 9.3 Frequency analysis techniques 9.4 Window effects and bandwidth 9.5 Time averaging and jitter 9.6 Average or difference 9.7 Band and line filtering and re-synthesis 9.8 Modulation 9.9 Pitch effects 9 .10 Phantoms References 13 9 13 9 14 0 14 2 14 8 15 2 15 7 15 8 16 1 16 3 16 5 16 6 10 Improvements 10 .1 Economics 10 .2 Improving the structure 10 .3... Drives 12 .1 Design philosophies 12 .2 Advantages and disadvantages 12 .3 Excitation phasing 12 .4 Excitation frequencies 12 .5 T.E testing 12 .6 Unexpected frequencies Reference 2 01 2 01 203 205 208 209 210 213 xii Contents 13 High Contact Ratio Gears 13 .1 Reasons for interest 13 .2 Design with Harris maps 13 .3 2 stage relief 13 .4 Comparisons 13 .5 Measurement of T.E References 215 215 216 217 218 219 222 14 Low... measurements 16 .4 Reciprocal theorem 16 .5 Sweep, impulse, noise or chirp 16 .6 Combining results 16 .7 Coherence 245 245 249 250 254 255 257 260 17 Couplings 17 .1 Advantages 17 .2 Problems 17 .3 Vibration generation 263 263 264 266 Contents xiii 18 Failures 18 .1 Connection with vibration 18 .2 Pitting 18 .3 Micropitting 18 .4 Cracking 18 .5 Scuffing 18 .6 Bearings 18 .7 Debris detection 18 .8 Couplings 18 .9 Loadings 18 .10 ... Ratio Gears 14 .1 Advantages 14 .2 Disadvantages 14 .3 Curvature problems 14 .4 Frequency gains 223 223 227 227 229 15 Condition Monitoring 15 .1 The problem 15 .2 Not frequency analysis 15 .3 Averaging or not 15 .4 Damage criteria 15 .5 Line elimination 15 .6 Scuffing - Smith Shocks 15 .7 Bearing signals References 2 31 2 31 232 233 234 237 238 2 41 243 16 Vibration Testing 16 .1 Objectives 16 .2 Hydraulic vibrators 16 .3... have taught me and broadened my knowledge while providing many fascinating problems for solution / Derek Smith Contents Preface v 1 Causes of Noise 1. 1 Possible causes of gear noise 1. 2 The basic idea of Transmission Error 1. 3 Gearbox internal responses 1. 4 External responses 1. 5 Overall path to noise 1. 6 T.E. -noise relationship References 1 1 3 6 8 8 9 11 2 Harris Mapping for Spur Gears 2 .1 Elastic deflections... Debris detection 18 .8 Couplings 18 .9 Loadings 18 .10 Overheating References 269 269 269 270 2 71 272 273 276 277 278 279 280 19 Strength v Noise 19 .1 The connection between strength and noise 19 .2 Design for low noise helicals 19 .3 Design sensitivity 19 .4 Buying problems 2 81 2 81 282 285 286 Units 289 Index 2 91 ... deflections of gears 2.2 Reasons for tip relief 2.3 Unloaded T.E for spur gears 2.4 Effect of load on T.E 2.5 Long, short or intermediate relief References 13 13 15 19 21 23 25 3 Theoretical Helical Effects 3 .1 Elastic averaging of T.E 3.2 Loading along contact line 3.3 Axial forces 3.4 Position variation 3.5 "Friction reversal" and "contact shock" effects 3.6 No-load condition References 27 27 29 31 31 33 35... problems of design, metrology, development and troubleshooting when noise and vibration occur In this area the standard specifications are of no help, so it is necessary to understand what is happening to cause the noise It is intended primarily for engineers in industry who are either buying-in gears or designing, manufacturing, and inspecting them and who encounter noise trouble or are asked to measure . levels 17 5 10 .6 Frequency changing 17 8 10 .7 Damping 17 9 10 .8 Production control options 18 1 References 18 3 11 . Lightly Loaded Gears 18 5 11 .1 Measurement problems 18 5 11 .2 Effects and . 10 6 7.8 Accuracy of measurement 11 0 7.9 Worms and wheels and spiral bevels 11 2 7 .10 Practical problems 11 3 7 .11 Comparisons 11 7 References 11 9 8. Recording and Storage 12 1 8 .1 . identification 18 7 11 .3 Simple predictions 18 9 11 .4 Possible changes 19 2 11 .5 Anti-backlash gears 19 3 11 .6 Modelling rattle 19 4 Reference 200 12 . Planetary and Split Drives 2 01 12 .1 Design