1、AGMA INFORMATION SHEET(This Information Sheet is NOT an AGMA Standard)AGMA914-B04AGMA 914- B04Revision of AGMA 299.01)AMERICAN GEAR MANUFACTURERS ASSOCIATIONGear Sound ManualPart I - Fundamentals of Sound as Related to GearsPart II - Sources, Specifications and Levels of Gear SoundPart III - Gear No
2、ise ControliiGear Sound ManualPart I - Fundamentals of Sound as Related to GearsPart II - Sources, Specifications and Levels of Gear SoundPart III - Gear Noise ControlAGMA 914-B04Revision of AGMA 299.01CAUTION NOTICE: AGMA technical publications are subject to constant improvement,revision or withdr
3、awal as dictated by experience. Any person who refers to any AGMAtechnical publication should be sure that the publication is the latest available from the As-sociation on the subject matter.Tables or other self-supporting sections may be referenced. Citations should read: SeeAGMA 914-B04, Gear Soun
4、d Manual: Part I - Fundamentals of Sound as Related toGears; Part II - Sources, Specifications and Levels of Gear Sound; Part III - Gear NoiseControl, published by the American Gear Manufacturers Association, 500 MontgomeryStreet, Suite 350, Alexandria, Virginia 22314, http:/www.agma.org.Approved Ma
5、rch 4, 2004ABSTRACTNoise measurement and control on gear driven equipment is dependent upon the individual characteristics ofthe prime mover, gear unit and driven machine, as well as their combined effects as a system in a particularacoustical environment.Because of the wide variation of gear driven
6、 systems and acoustical environments, this manual attempts toindicate certain areas where special considerations might be necessary, and must be agreed upon betweenpurchaser and the gear manufacturer, when discussing gear sounds.The information is arranged in three parts. Part I presents the fundame
7、ntals necessary to understand sound asrelated to gears. Part II describes the sources, specifications and levels of gear sound. Reduction or control ofnoise, as addressed in Part III, requires attention to connecting equipment and the acoustical environment, aswell as the gear unit.Published byAmeri
8、can Gear Manufacturers Association500 Montgomery Street, Suite 350, Alexandria, Virginia 22314Copyright 2004 by American Gear Manufacturers AssociationAll rights reserved.No part of this publication may be reproduced in any form, in an electronicretrieval system or otherwise, without prior written p
9、ermission of the publisher.Printed in the United States of AmericaISBN: 1-55589-820-3AmericanGearManufacturersAssociationAGMA 914- B04AMERICAN GEAR MANUFACTURERS ASSOCIATIONiii AGMA 2004 - All rights reservedContentsPageForeword vi.Part I - Fundamentals of Sound as Related to Gears1.1 Scope 11.2 Ref
10、erences 1.1.3 Symbols and definitions 11.4 What is sound? 21.5 Description of sound 2.1.6 Sound or noise? 7.1.7 Generation of sound in gear units 81.8 Sound transmission 10.1.9 Noise control 10.Part II - Sources, Specifications and Levels of Gear Sound2.1 Gear sound sources 112.2 Sound spectrum expe
11、rience 172.3 Specification and standards 172.4 Gear system sound levels 20Part III - Gear Noise Control3.1 Source noise control 263.2 Gear design noise control 263.3 Gear housing noise control 29.3.4 Bearing noise control 303.5 Shaft and hub design noise control 313.6 Lubrication noise control 31.3.
12、7 Noise control with system analysis 313.8 Noise of gear unit accessories 323.9 Noise control in the transmission path 32.3.10 Noise control materials 343.11 Total enclosures 353.12 Control summary 36.Figures1-1 Sound wave forms 3.1-2 Frequency responses 51-3 Typical A-weighted sound levels 6.1-4 Ca
13、lculation for expected sound level 91-5 Chart for combining levels of uncorrelated noise signals 9.2-1 Sound pressure level vs. frequency 13.2-2 Triple reduction gear motor frequency analysis 3600 rpm input, ratio -45 to 1 132-3 Gear noise analysis by constant-bandwidth, 10 Hz filter 152-4 Unfiltere
14、d sound measurement 16.2-5 Fast Fourier Transform analysis of sound 162-6 Waterfall analysis of gear unit sound 17.2-7 Sound test microphone position 20.2-8 AGMA typical maximum and average sound pressure level vs. high speedmesh pitch line velocity 212-9 AGMA typical maximum and average sound press
15、ure level vs. catalogpower rating 22.AGMA 914- B04 AMERICAN GEAR MANUFACTURERS ASSOCIATIONiv AGMA 2004 - All rights reserved2-10 Sound pressure level vs. pitch line velocity taken 3 feet from housing 222-11 Change in dBA sound pressure level relative to that at 1750 rpm (LPA)vs. input speed 23.2-12
16、Sound pressure level vs. worm speed 23.2-13 Change in dBA sound pressure level relative to that at no load (LPA)vs. P/Pat24.2-14 Change in dBA sound pressure level relative to that at no load (LPA)vs. P/PR24.2-15 Sound pressure level vs. center distance - taken 5 feet from housing 253-1 Contact of h
17、elical gears 283-2 Contact of spur gears 28.3-3 Variation of length of contact lines/face ratio with face width 29.3-4 Tip relief on gear teeth 30.3-5 Sound transmission paths for gear unit in typical installation 333-6 Noise attenuating devices in gear unit surroundings 33.3-7 Effect of noise atten
18、uating devices in gear unit surroundings - octaveband results 343-8 Sound transmission paths for gear unit with vibration isolators andtotal enclosure 36.Tables1-1 Symbols and definitions 11-2 Center and approximate cut-off frequencies for standard set ofcontiguous-octave and one-third-octave bands
19、covering audiofrequency range 7.2-1 Common sources of airborne and structure-borne sounds generated ingear drive systems 122-2 Occupational noise exposure - OSHA Regulation (Standard 29 CFR) 182-3 ANSI noise specifications 182-4 International standards 192-5 No twist steel rod mills “A” weighted sou
20、nd levels 253-1 Considerations for noise control 26.AGMA 914- B04AMERICAN GEAR MANUFACTURERS ASSOCIATIONv AGMA 2004 - All rights reservedForewordThe foreword, footnotes and annexes, if any, in this document are provided forinformational purposes only and are not to be construed as a part of AGMA Inf
21、ormationSheet 914-B04, Gear Sound Manual: Part I - Fundamentals of Sound as Related to Gears;Part II - Sources, Specifications and Levels of Gear Sound; Part III - Gear Noise Control.Concern with industrial noise created a need for a sound standard on all types of products.Noise measurement, control
22、 and attenuation on gear driven equipment is dependent uponthe individual characteristics of the prime mover, gear unit, and driven machine - as well astheir combined effects as a system in a particular acoustical environment.Proper assessment of these considerations is essential for realistic deter
23、mination ofacoustic values. The knowledge and judgment required to properly evaluate the variousfactors comes primarily from years of accumulated experience in designing, manufacturing,and operating gear units. For this reason, the detailed treatment of the testing and resultantconclusions for speci
24、fic product applications is best accomplished by experts in the field.The complexity makes most sound standards difficult to apply or interpret properly. TheAGMA Acoustical Technology Committee developed the Gear Sound Manual 299.01 toprovide improved communication between project engineers, gear ma
25、nufacturer, and userin the areas of Fundamentals of Sound as Related To Gears (Part I), Sources,Specifications and Levels of Gear Sound (Part II), and Gear Noise Control (Part III).This Information Sheet was originally issued as three separate documents: AGMA 299.01,Section I, Fundamentals of Sound
26、as Related to Gears; AGMA 299.01, Section II, Sources,Specifications and Levels of Gear Sound; and AGMA 299.01 Section III, Gear NoiseControl. Section I was approved by the membership in January 1978, Section II wasapproved in October 1978, and Section III was approved in October 1978. Combining the
27、three entitled, AGMA SOUND MANUAL, was approved by the AGMA Technical DivisionExecutive Committee in October 1987.The first draft of AGMA 914-B04 was made in November, 2002. It combines all three partsinto one document with three clauses, updates references, and adds a subclause on FastFourier Trans
28、form analysis. It was approved by the AGMA membership in March, 2004.Suggestions for improvement of this document will be welcome. They should be sent to theAmerican Gear Manufacturers Association, 500 Montgomery Street, Suite 350, Alexandria,Virginia 22314.AGMA 914- B04 AMERICAN GEAR MANUFACTURERS
29、ASSOCIATIONvi AGMA 2004 - All rights reservedPERSONNEL of the AGMA Sound and Vibration CommitteeChairman: Darwin D. Behlke Twin Disc, IncorporatedVice Chairman: Richard A. Schunck Falk Corporation.ACTIVE MEMBERSJ.B. Amendola MAAG Gear AGL. Lloyd Lufkin Industries, Inc.J.J. Luz General Electric Compa
30、nyJ.L. Radovich Davis-Standard.J.R. Sears General Motors CorporationASSOCIATE MEMBERSE.J. Bodensieck Bodensieck Engineering Company.D.L. Borden D.L. Borden, Inc.F. Choy University of AkronD. Coffey General Motors Corporation.D.R. Houser Ohio State UniversityA.J. Lemanski Penn State University.J.V. L
31、isiecki Falk Corporation.W.D. Mark Penn State UniversityH. Minasian Stoneridge Control Devices, IncG.W. Nagorny Nagorny - frequency;- velocity;- wavelength;- w a v e f o r m .1.4.1 AmplitudeAmplitude is the amount of variation in the pressurereading of the medium, relative to a standardreference pre
32、ssure. Amplitude determines the ener-gy level or strength of the sound, normally expressedin terms of a decibel level.1.4.2 FrequencyFrequency is the number of variations in theamplitude per a given period of time, normallyexpressed in Hertz (cycles per second).1.4.3 VelocityVelocity of the sound is
33、 the speed of the wave, and isa function of the elastic modulus and the massdensity of the medium.1.4.4 WavelengthWavelength is the distance between adjacent wavesof the same frequency. The relationship of frequen-cy, velocity, and wavelength is expressed by: =vf(1.1)where is wavelength;v is velocit
34、y;f is frequency.1.4.5 WaveformWaveform defines the type of sound wave, i.e.,whether the wave is simple (sinusoidal), complexdeterministic (periodic), or a complex random waveconsisting of multiple frequencies, harmonics, ran-dom pulses, etc. See figure 1-1.1.5 Description of sound1.5.1 DescriptionS
35、ound is commonly measured or described by oneor more of the following characteristics:Level- sound pressure level;- sound power level.Frequency content- A, B, and C weighing networks;- octave and 1/3 octave band filters;- narrow band filters.Descriptive properties- sound intensity;- loudness;- pitch
36、;- tone;- directivity.1.5.2 LevelThe level of sound is normally described in terms ofeither sound pressure level at a given distance fromthe source or sound power level. In each of these,the desired quantity (pressure or power) is ex-pressed in the numerator of a ratio with the referencelevel as the
37、 denominator. Because of the extremelywide range of levels measured (very small toextremely large) in everyday environments, bothpressure and power ratios are expressed by loga-rithmic scales.1.5.2.1 Sound pressure level, LpSound pressure level, Lp, expressed in decibels, is20 times the logarithm to
38、 the base 10 of the ratio ofAGMA 914- B04AMERICAN GEAR MANUFACTURERS ASSOCIATION3 AGMA 2004 - All rights reservedthe sound pressure being measured to the referencesound pressure.Lp= 20 log10ppo,dBre 20 mNm2 (1.2)wherep is sound pressure being measured, mN/m2;pois reference sound pressure, 20 mN/m2.T
39、he reference sound pressure, po, is internationallyaccepted as 20 micro Newtons/meter squared,which is about the threshold of normal hearing at afrequency of 1000 Hz. All sound measuring instru-ments respond to sound pressure.Example: The sound pressure near a punch press ismeasured as being 0.0025
40、psi. What is the soundpressure re 20 mN/m2in dB?Ik-ISingle frequencysinusoidal wave formExample of complexwave formSinusoidal wave form “A”when combined with form “B”results in complex form A + BPressurePressurePressurePressurePressurePressurePeriod(time)TimeTimeTimeForm “A”Form “B”Form A + BAmplitu
41、deAmplitudeTimeExample of complex - random waveA + B + Random pulsesFrequency =1PeriodWavelength(distance)Velocity =WavelengthPeriod(speed of sound)Wavelength = Velocity PeriodFigure 1- 1 - Sound wave formsAGMA 914- B04 AMERICAN GEAR MANUFACTURERS ASSOCIATION4 AGMA 2004 - All rights reservedSince 1.
42、0 psi = 6890 N/m2, then 0.0025 psi = 17.225N/m2.= 118.7 dBre 20 mNm2(1.3)Lp= 20 log1017.22Nm220 mNm2= 20 log108.612 105So we would commonly say the noise of the punchpress is 119 dB.1.5.2.2 Sound power level, LwSound power level, Lw, is the ratio, expressed indecibels, of the sound power under consi
43、deration tothe reference sound power, one picowatt (10- 1 2watt).Lw= 10 log10WWo,dBre 1012watt (1.4)whereW is sound power under consideration,picowatt;Wois reference sound power, picowatt.Sound power cannot be measured directly. It can beobtained only by calculation after having measuredsound pressu
44、re levels in a known acoustical environ-ment (i.e., anechoic chambers, reverberant rooms,etc.).1.5.3 Frequency contentThe frequency content of a sound is normallydescribed as a particular frequency or by the levelcontent in a band of frequencies.1.5.3.1 A, B and C weighing networksThe frequency resp
45、onse of the human ear is not asgood as a sound level meter. Therefore, variousweighing networks (filters) have been established sothat the objective meter measurement will comeclose to indicating what the ear hears. Figure 1-2shows the attenuation of the A, B and C weighingscales of a sound level me
46、ter. The A scale is afiltering system that roughly matches the humanears response at sound levels below 55 dB. The Bscale roughly matches the ear at levels between 55dB and 85 dB, and the C scale is to match above 85dB. However, the A scale (sound pressure levelmeasured in dBA) has received prominen
47、ce due toits use in OSHA, for measuring levels up to 115 dB. Itis interesting to note the tremendous attenuation theA scale performs on low frequencies. At about 95Hz, for example, there is about a 20 dB attenuation.Only 1/10 of the actual sound is indicated on themeter. Therefore, gears generating
48、low frequencysound are more likely to pass a dBA specification,and be less annoying to the ear. AGMA soundstandards use an A weighted sound level (dBA) as acommon indication of performance. See figure 1-3.1.5.3.2 Octave and 1/3 octave band filterAnother filtering system often used in the measure-men
49、t of sound is the octave and 1/3 octave bands.These are discrete filters which only register a limitedrange of frequencies. The octave and 1/3 octavebands are used for analytical work and are usuallyspecified by their center frequencies. See table 1-2.The 63 Hz octave band to the 8000 Hz octave bandare most commonly used in industry specifications.1.5.3.3 Narrow band filtersA narrow band filter (spectrum analyzer) is similar tooctave band filters, how
