Gear Noise and Vibration

by Smith; J. Derek

• ISBN13: 9780824741297
• ISBN10: 0824741293
• Edition: 2nd
• Format: Hardcover
• Copyright: 2003-04-08
• Publisher: CRC Press

Summary

Based on over 40 years of consultation and teaching experience, Gear Noise and Vibration demonstrates logical gear noise and vibration approaches without the use of complex mathematics or lengthy computation methods. The Second Edition offers new and extended discussions on high- and low-contact ratio gears, lightly loaded gears, planetary and split drives, and transmission error (T.E.) measurement. A straightforward source for enhanced gear design, assessment, and development practices, the book is enriched with more than 150 figures. It offers the most economic solutions to gear design obstacles and details current challenges and troubleshooting schemes for improved gear installation.

Author Biography

J. Derek Smith is Lecturer and Researcher in the Engineering Department of Cambridge University, England.

Table of Contents

Preface	v
Causes of Noise	1	(12)
Possible causes of gear noise	1	(2)
The basic idea of Transmission Error	3	(3)
Gearbox internal responses	6	(2)
External responses	8	(1)
Overall path to noise	8	(1)
T.E.-noise relationship	9	(4)
References	11	(2)
Harris Mapping for Spur Gears	13	(14)
Elastic deflections of gears	13	(2)
Reasons for tip relief	15	(4)
Unloaded T.E. for spur gears	19	(2)
Effect of load on T.E.	21	(2)
Long, short or intermediate relief	23	(4)
References	25	(2)
Theoretical Helical Effects	27	(10)
Elastic averaging of T.E.	27	(2)
Loading along contact line	29	(2)
Axial forces	31	(1)
Position variation	31	(2)
``Friction reversal'' and ``contact shock'' effects	33	(2)
No-load condition	35	(2)
References	35	(2)
Prediction of Static T.E.	37	(24)
Possibilities and problems	37	(1)
Thin slice assumptions	38	(2)
Tooth shape assumptions	40	(4)
Method of approach	44	(4)
Program with results	48	(5)
Accuracy of estimates and assumptions	53	(5)
Design options for low noise	58	(3)
References	59	(2)
Prediction of Dynamic Effects	61	(16)
Modelling of gears in 2-D	61	(3)
Time marching approach	64	(1)
Starting conditions	65	(1)
Dynamic program	66	(5)
Stability and step length	71	(2)
Accuracy of assumptions	73	(2)
Sound predictions	75	(2)
References	76	(1)
Measurements	77	(16)
What to measure	77	(2)
Practical measurements	79	(5)
Calibrations	84	(1)
Measurement of internal resonances	85	(2)
Measurement of external resonances	87	(1)
Isolator transmission	88	(2)
Once per revolution marker	90	(3)
References	92	(1)
Transmission Error Measurement	93	(28)
Original approach	93	(2)
Batching approach	95	(1)
Velocity approach	96	(3)
High speed approach	99	(4)
Tangential accelerometers	103	(1)
Effect of dynamics	104	(2)
Choice of encoders	106	(4)
Accuracy of measurement	110	(2)
Worms and wheels and spiral bevels	112	(1)
Practical problems	113	(4)
Comparisons	117	(4)
References	119	(2)
Recording and Storage	121	(18)
Is recording required?	121	(1)
Digital v. analog	122	(1)
Current PC limits	123	(1)
Form of results	124	(3)
Aliasing and filters	127	(5)
Information compression	132	(4)
Archive information	136	(3)
References	137	(2)
Analysis Techniques	139	(28)
Types of noise and irritation	139	(1)
Problem identification	140	(2)
Frequency analysis techniques	142	(6)
Window effects and bandwidth	148	(4)
Time averaging and jitter	152	(5)
Average or difference	157	(1)
Band and line filtering and re-synthesis	158	(3)
Modulation	161	(2)
Pitch effects	163	(2)
Phantoms	165	(2)
References	166	(1)
Improvements	167	(18)
Economics	167	(2)
Improving the structure	169	(2)
Improving the isolation	171	(3)
Reducing the T.E.	174	(1)
Permissible T.E. levels	175	(3)
Frequency changing	178	(1)
Damping	179	(2)
Production control options	181	(4)
References	183	(2)
Lightly Loaded Gears	185	(16)
Measurement problems	185	(2)
Effects and identification	187	(2)
Simple predictions	189	(3)
Possible changes	192	(1)
Anti-backlash gears	193	(1)
Modelling rattle	194	(7)
Reference	200	(1)
Planetary and Split Drives	201	(14)
Design philosophies	201	(2)
Advantages and disadvantages	203	(2)
Excitation phasing	205	(3)
Excitation frequencies	208	(1)
T.E. testing	209	(1)
Unexpected frequencies	210	(5)
Reference	213	(2)
High Contact Ratio Gears	215	(8)
Reasons for interest	215	(1)
Design with Harris maps	216	(1)
2 stage relief	217	(1)
Comparisons	218	(1)
Measurement of T.E.	219	(4)
References	222	(1)
Low Contact Ratio Gears	223	(8)
Advantages	223	(4)
Disadvantages	227	(1)
Curvature problems	227	(2)
Frequency gains	229	(2)
Condition Monitoring	231	(14)
The problem	231	(1)
Not frequency analysis	232	(1)
Averaging or not	233	(1)
Damage criteria	234	(3)
Line elimination	237	(1)
Scuffing - Smith Shocks	238	(3)
Bearing signals	241	(4)
References	243	(2)
Vibration Testing	245	(18)
Objectives	245	(4)
Hydraulic vibrators	249	(1)
Hammer measurements	250	(4)
Reciprocal theorem	254	(1)
Sweep, impulse, noise or chirp	255	(2)
Combining results	257	(3)
Coherence	260	(3)
Couplings	263	(6)
Advantages	263	(1)
Problems	264	(2)
Vibration generation	266	(3)
Failures	269	(12)
Connection with vibration	269	(1)
Pitting	269	(1)
Micropitting	270	(1)
Cracking	271	(1)
Scuffing	272	(1)
Bearings	273	(3)
Debris detection	276	(1)
Couplings	277	(1)
Loadings	278	(1)
Overheating	279	(2)
References	280	(1)
Strength v. Noise	281	(8)
The connection between strength and noise	281	(1)
Design for low noise helicals	282	(3)
Design sensitivity	285	(1)
Buying problems	286	(3)
Units	289	(2)
Index	291