1、BRITISH STANDARD BS 7676-2: 1993 ISO 8579-2: 1993 Acceptance code for gears Part 2: Determination of mechanical vibrations of gear units during acceptance testing UDC 621.833:534.6BS7676-2:1993 This British Standard, having been prepared under the directionof the General Mechanical Engineering Stand
2、ards Policy Committee, waspublished under the authorityof the Standards Boardand comes into effect on 15August1993 BSI 10-1999 The following BSI references relate to the work on this standard: Committee reference MCE/5 Draft for comment 89/72664 DC ISBN 0 580 21897 X Committees responsible for this
3、British Standard The preparation of this British Standard was entrusted by the Machinery and Components Standards Policy Committee (MCE/-) to Technical Committee MCE/5, upon which the following bodies were represented: The following bodies were also represented in the drafting of the standard, throu
4、gh subcommittees and panels: British Gear Association Gauge and Tool Makers Association British Horological Federation Institution of Mechanical Engineers British Railways Board Lloyds Register of Shipping Engineering Equipment and Materials Users London Underground Ltd. Association Ministry of Defe
5、nce Federation of British Engineers Tool Power Generation Contractors Association Manufacturers (BEAMA Ltd.) Federation of Manufacturers of Construction Equipment and Cranes Advanced Manufacturing Technology Engineering Industries Association Research Institute Fan Manufacturers Association Agricult
6、ural Engineers Association Federation of Associations of Specialists and Association of Building Engineers Subcontractors Association of Consulting Engineers Federation of Manufacturers of Construction British Broadcasting Corporation Equipment and Cranes British Cement Association Federation of Pil
7、ing Specialists British Compressed Air Society Health and Safety Executive British Industrial Truck Association Hevac Association British Occupational Hygiene Society Institute of Acoustics British Steel plc Institute of Occupational Hygienists British Telecommunications plc Institute of Physics Con
8、struction Industry Research and Institute of Sound and Vibration Research Information Association Institution of Electrical Engineers Department of Health Institution of Mechanical Engineers Department of the Environment (Building Rotating Electrical Machines Association Research Establishment) (BEA
9、MA Ltd.) Department of Trade and Industry (National Royal Institute of British Architects Engineering Laboratory) Society of Environmental Engineers Department of Trade and Industry (National University of Liverpool Physical Laboratory) University of Manchester EEA (the Association of Electronics, T
10、elecommunications and Business Equipment Industries) Amendments issued since publication Amd. No. Date CommentsBS7676-2:1993 BSI 10-1999 i Contents Page Committees responsible Inside front cover National foreword ii 1 Scope 1 2 Normative reference 1 3 Definitions 1 4 General 2 5 Instrumentation 2 6
11、Vibration measurements 3 7 Testing 3 8 Acceptance values 4 9 Test report 6 Annex A (informative) Relationship between displacement, velocity andacceleration waveforms 7 Annex B (informative) Effects of the system 9 Annex C (informative) Vibration instruments and characteristic considerations 9 Annex
12、 D (informative) Subjective vibration ratings 11 Annex E (informative) Bibliography 12 Figure 1 Rating curves for shaft vibration 5 Figure 2 Rating curves for housing vibration 5 Figure A.1 Waveform 7 Figure A.2 Vibration amplitude relationships 8 Figure D.1 Subjective vibration ratings 12 Table 1 3
13、 Table A.1 8 Table D.1 11 List of references Inside back coverBS7676-2:1993 ii BSI 10-1999 National foreword This Part of BS7676 has been prepared under the direction of the Machinery and Components Standards Policy Committee. It is identical with ISO8579-2:1993 Acceptance code for gears Part 2: Det
14、ermination of mechanical vibrations of gear units during acceptance testing which was prepared jointly by Technical Committee ISO/TC60, Gear, and ISO/TC43, Acoustics, of the International Organization for Standardization (ISO), in which the United Kingdom played an active part. BS7676 comprises the
15、following Parts: Part 1: Determination of airborne sound power levels emitted by gear units; Part 2: Determination of mechanical vibrations of gear units during acceptance testing. A British Standard does not purport to include all the necessary provisions of a contract. Users of British Standards a
16、re responsible for their correct application. Compliance with a British Standard does not of itself confer immunity from legal obligations. Cross-reference International Standard Corresponding British Standard ISO2041:1990 BS3015:1991 Glossary of terms relating to mechanical vibration and shock (Ide
17、ntical) Summary of pages This document comprises a front cover, an inside front cover, pages i and ii, pages1 to 12, an inside back cover and a back cover. This standard has been updated (see copyright date) and may have had amendments incorporated. This will be indicated in the amendment table on t
18、he inside front cover.BS7676-2:1993 BSI 10-1999 1 1 Scope 1.1 This part of ISO8579 specifies the methods for determining mechanical vibration of individually housed, enclosed, speed-increasing and speed-reducing gear units. It specifies methods for measuring housing and shaft vibrations, and the typ
19、es of instrumentation, measurement methods and testing procedures for determining vibration levels. Vibration grades for acceptance are included. It does not include torsional vibration measurements of a geared system. This part of ISO8579 applies only to a gear unit under test and operating within
20、its design speed, load, temperature range and lubrication for acceptance testing at the manufacturers facility. The gear unit may be tested at another location if agreed upon and operated in accordance with the manufacturers recommendations. Other International Standards on vibration evaluation may
21、be required for measuring gear unit vibration in field service. This part of ISO8579 does not apply to special orauxiliary drive trains, such as integrated gear-driven compressors, pumps, turbines, etc., and power take-off gears. NOTE 1Acceptance limits for tests of these types of equipment should b
22、e independently specified. However, if negotiated, this or other appropriate standards may be applied to such equipment. 1.2 Special provisions may be required for vibration measurements: the type of measurement and acceptance level should therefore be agreed between the manufacturer and purchaser a
23、t an early stage of negotiation. 2 Normative reference The following standard contains provisions which, through reference in this text, constitute provisions of this part of ISO8579. At the time of publication, the edition indicated was valid. All standards are subject to revision, and parties to a
24、greements based on this part of ISO8579 are encouraged to investigate the possibility of applying the most recent edition of the standard indicated below. Members of IEC and ISO maintain registers of currently valid International Standards. ISO 2041:1990, Vibration and shock Vocabulary. 3 Definition
25、s For the purposes of this part of ISO8579, the definitions given in ISO2041, together with the following, apply. For the convenience of users of this part of ISO8579, some definitions are quoted from ISO2041:1990. 3.1 non-contact transducer a transducer which converts a distance or displacement to
26、an electrical signal that is proportional to the distance or displacement 3.2 acceleration a vector that specifies the time-derivative of velocity ISO 2041, 1.3 NOTE 2See Annex A. 3.3 displacement; relative displacement a vector quantity that specifies the change of position of a body, or particle,
27、with respect to a reference frame ISO 2041, 1.1 NOTE 3See Annex A. 3.4 frequency response the output signal expressed as a function of the frequency of the input signal. The frequency response is usually given graphically by curves showing the relationship of the output signal and, where applicable,
28、 phase shift or phase angle as a function of frequency ISO 2041, B.13 3.5 peak-to-peak value (of a vibration) the algebraic difference between the extreme values of the vibration ISO 2041, 2.35 3.6 root-mean-square value; r.m.s. value for a single-valued function f(t) over an interval of time betwee
29、n t 1and t 2 , the square root of the average of the squared values over the interval NOTE 4The r.m.s. value of a single-valued function f(t) over an interval between t 1and t 2is NOTE 5In vibration theory, the mean value of the vibration is equal to zero. In this case, the r.m.s. value is equal to
30、the standard deviation (B) and the mean-square value is equal to the variance (B 2 ). ISO 2041, A.37BS7676-2:1993 2 BSI 10-1999 3.7 transducer a device designed to receive energy from one system and supply energy, of either the same or of a different kind, to another in such a manner that the desire
31、d characteristics of the input energy appear at the output ISO 2041, 4.1 3.8 velocity; relative velocity a vector that specifies the time-derivative of displacement ISO 2041, 1.2 NOTE 6See Annex A. 3.9 vibration the variation with time of the magnitude of a quantity which is descriptive of the motio
32、n or position of a mechanical system, when the magnitude is alternately greater and smaller than some average value or reference ISO 2041, 2.1 4 General 4.1 System considered The gear unit should be tested in such a manner as to minimize as far as possible effects of the system (see Annex B). 4.2 Ef
33、fects of system Vibration levels of the gear unit in field service may be adversely affected by factors beyond the control of the gear manufacturer, as listed in Annex B. It is preferable to estimate the vibration of the whole system and to check the system effects at the initial design stage of a t
34、ransmission system. The responsibility for checking should be clearly defined during this stage and all interested parties made aware of the decision. 4.3 Housing or shaft measurements The vibrations of a gear unit can be measured in two ways, i.e. on the housing or on the shafts. Housing vibration
35、measurements are preferred for gear units operating with rolling contact bearings when the clearance in such bearings is small and little relative movement normally occurs between the shaft and housing. Both shaft and housing vibration measurements may be made on gear units operating with plain jour
36、nal bearings. Shaft vibration measurements can provide detailed information which may not be evident from housing measurements, but only over a limited frequency range (typically0Hz to500Hz). Housing vibration measurements have the advantage of having both an extended frequency range and an extended
37、 dynamic range which are essential when considering frequency of tooth contact. See the provisions of 1.2. Care shall be taken when choosing the measurement instrument for a given gear unit and operating conditions, as each instrument has its own characteristics (see Annex C). It is often useful to
38、combine both shaft and housing vibration measurements to obtain an absolute motion of the gear unit shaft. When operating conditions during acceptance testing deviate considerably from field service, the differences shall be taken into account in the assessment of vibration data. 5 Instrumentation 5
39、.1 Type Vibration shall be measured using a transducer and an instrument with a known accuracy for the measurement of velocity and displacement across a known frequency range. The instrument shall also have an electrical output signal of known accuracy related to velocity or displacement, or both. T
40、he transducer shall be used within its calibrated limits for the mounting method and for the prevailing environmental conditions such as temperature, magnetic field, surface finish, etc. The type and use of vibration instrumentation systems shall comply with the appropriate International Standards.
41、The instrumentation should preferably include a facility for narrow-band frequency analysis with a bandwidth not exceeding one-third-octave. 5.1.1 Shaft measurement instrumentation The recommended type of transducer for measuring shaft vibration is a non-contacting transducer. The instrument shall a
42、llow a reading of peak-to-peak values of vibration displacement to be taken. However, contacting transducers are acceptable if the rotational frequency of the shaft is less than3000 min 1 , the signal frequency is less than200 Hz, and surface rubbing velocity is less than30m/s.BS7676-2:1993 BSI 10-1
43、999 3 5.1.2 Housing measurement instrumentation The recommended type of transducer for measuring housing vibration is a seismic transducer. The equipment shall include an electrical instrument with a true r.m.s. rectification characteristic giving the r.m.s. values of vibration velocity in millimetr
44、es per second. The mounting method can affect the frequency response of the transducer; it should therefore be mounted with a screw or stud, or using bonding material. Magnetic mounting using lightweight accelerometers, may be acceptable for frequencies up to3000 Hz if the highest fundamental freque
45、ncy of tooth meshing is less than1000 Hz. Hand-held contact measurements are not acceptable. 5.2 Measurement frequency range The instrument measurement frequency range shall be capable of measuring the lowest shaft rotational speed and the highest tooth mesh frequency. The shaft displacement frequen
46、cy measurement range should be between0Hz and500Hz. The housing velocity frequency measurement range when using integrated acceleration measurements should preferably be between10Hz and10000Hz or more. 5.3 Permissible error The measuring instrumentation system, including both the transducer and read
47、-out instrumentation shall be capable of indicating the vibration level within a permissible error of10% of the reading over the entire operating temperature range. 5.4 Calibration The vibration read-out instrumentation shall be checked against a reference signal and any specified adjustments made i
48、mmediately before and rechecked immediately after each series of gear unit vibration measurements. Calibrations of the complete measuring equipment should be carried out at least once every2years. 6 Vibration measurements 6.1 Shaft measurements Vibration displacement of the shafts should preferably
49、be measured relative to the housing. Non-contacting transducers should be used, located as near to a bearing as possible and attached to rigid housing sections. Shaft vibration shall be measured in three orthogonal directions (mutually perpendicular axes), one of which shall be parallel to the shaft axis. Only one such axial transducer per shaft is necessary. The number and location of transducers shall be agreed upon between the purchaser and manufacturer. The mechanical and electrical run-out should preferably not exceed25% of the allo
