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1、IS0 8662- 1 INTERNATIONAL STANDARD INTERNATIONAL ORGANIZATION FOR STANDARDIZATION ORGANISATION INTERNATIONALE DE NORMALISATION MEXAYHAPOAHAR OPrAHkl3AL a0 is the reference acceleration equal to 1O-6 m/s2, as specified in IS0 1683. 3.2 Frequency analysis Measurement shall be made in octave bands with
2、 centre fre- quencies of 8 to 1 6OCl Hz or in one-third octave bands with cen- tre frequencies of 6,3 to 1 250 Hz. NOTES 1 A frequency analysis in octave bands is regarded to be necessary in order to judge the validity of the measurement of the weighted value (see 3.3 and 4.31, e.g. high values in b
3、ands below the repetition fre- quency of the tool may indicate the presence of non-linear effects. 2 Octave band values can be directly measured or calculated from one-third octave band values. 3.3 Weighted acceleration Weighted acceleration values, ah,w, can be obtained either by measurement using
4、the weighting filter for hand-arm vibration measurements defined in IS0 8041 or by calculation from one- third octave band data, using the weighting factors specified in IS0 5349. NOTE - These two methods may produce different results owing to differences in the curves, the tolerances, and the filte
5、r charac- teristics in the electronic filtering networks. 4 Instrumentation 4.1 Specification of transducer A transducer for measuring acceleration, such as a piezo- electric device, shall be used in conjunction with a suitable preamplifier. IS0 8041 shall be consulted for the specification of the m
6、easuring equipment. The total mass of the vibration transducer and its mounting shall be small in relation to that of the handle; it shall preferably be less than 50 g and not more than 5 % of the mass of the tool complete with accessories. Specifications .such as the transverse sensitivity (less th
7、an 10 %I, the ambient temperature range and the maximum shock acceleration shall be considered in the selection of accelerometers. NOTE - Under certain conditions, particularly when mounting a transducer on a handle made of a non-metallic material, e.g. plastic or rubber, or on a very light handle (
8、approximately less than 3 % of the total mass of the tool complete with accessories), the above-stated mass of 50 g may lead to measurement errors. In this case it is necessary to use a transducer as small and light as possible. 4.2 Fastening of transducer The transducer and the mechanical filter, i
9、f used, shall be mounted firmly, for example by using a threaded stud or clamp. Further details are given for individual tools in the relevant parts of IS0 8662. In all cases the mounting shall be in accordance with the transducer manufacturers instructions. For acceler- ometers, the mounting shall
10、be in accordance with IS0 5348. NOTE - The measurement of vibration on handles with resilient covers can be accomplished by using a special adaptor between the hand and the handle. The adaptor may consist of a suitably formed light rigid plate with a suitable mounting arrangement for the ac- celerom
11、eter used. Care should be taken that the mass, size and shape of the adaptor do not significantly influence the signal from the transducer in the frequency range of interest. 4.3 Mechanical filter For percussive tools, particularly those with an all-metal hous- ing, the use of a mechanical filter to
12、gether with the ac- celerometer is recommended. However, if it is known that no measurement errors are introduced when the mechanical filter is not used, it need not be used. The measurement errors may be, for example, periodic d.c. shifts which contribute to the vibration signal in the frequency ra
13、nge of interest. NOTE - High acceleration in the high-frequency components of the vibration may cause the accelerometer to generate false signals in the frequency range of interest because of excitation of the resonance of the transducer itself. Mechanical filters may be used to reduce the high-freq
14、uency components of the vibration input into the accelerometer. The mechanical filter, if used, shall be adapted to the mass of the accelerometer to produce a response from 6,3 Hz up to 1,5 kHz. The cut-off frequency of the mechanical filter shall be at least a factor of five below the resonance fre
15、quency of the accelerometer. 1) At present at the stage of draft. 2 Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=NASA Technical Standards 1/9972545001 Not for Resale, 04/27/2007 08:38:50 MDTNo reproduction or networking permitted without li
16、cense from IHS -,-,- 4.4 Frequency filters IS0 6662-l : 1988 (El 5.2 Measurement location If octave band and one-third octave band filters are used they shall be as specified in IEC Publication 225. 4.5 Weighting filter and r.m.s. detector If a weighting filter and r.m.s. detector for hand-arm vibra
17、tion measurements are used they shall be as specified in IS0 8041. The suggested methods for obtaining the individual r.m.s. values are as follows. If the signal for analysis is of short duration, or if its magnitude varies substantially with time, a simple analysis cannot be made. In order to obtai
18、n r.m.s. values under these circumstances, it is necessary to use an integrating meter or analyser which is equipped with “linear integration” facilities. It is recommended that “linear integration” analysis be adopted as the preferred method. The type of analyser normally used for noise analysis ca
19、n be used only when the signal is relatively steady with time or is of sufficient duration. In such circumstances, the time constant chosen shall be appropriate for the signal duration. 4.6 Signal recording The vibration signal may be stored for later evaluation using a suitable high quality instrum
20、entation recorder. The vibration spectrum shall be corrected for any deviation from a flat frequency response of the recorder. The corrections to the octave band centre frequencies or the one-third octave band frequencies shall be recorded in the test report. 4.7 Auxiliary equipment The auxiliary eq
21、uipment for monitoring the running condition (electrical conditions, power, air pressure, rotational speed, etc.) and the working conditions of specific tools will be specified in subsequent parts of IS0 8662. 4.8 Calibration The measuring chain including the transducer shall be calibrated (see IS0
22、8041 and IS0 5347). 5 Measurement direction and location 5.1 Measurement direction A basicentric coordinate system) shall be used. When ap- propriate, measurements shall be made in the dominant axis. This axis is defined for specific tools in subsequent parts of IS0 8662. If no dominant axis exists,
23、 then measurements shall be made in all three axes. Measurements shall be carried out at a point half-way along the length of the handles or at such places where an operator nor- mally holds the tool during a typical operation. The specifica- tion of measurement positions on individual tools is give
24、n in subsequent parts of IS0 8662. 6 Determination of working procedure 6.1 General The working procedure shall be specified in as much detail as necessary to achieve appropriate reproducibility. A working procedure similar to that of a typical real working situation is preferred. The number of runs
25、 and the length of each run shall be suffi- cient to obtain an appropriate accuracy. These data are specified for individual tools in the relevant parts of IS0 b) n/w; c) model number; d) serial number; e) running conditions; f) mass. The description of the inserted tool shall include the following
26、details : a) manufacturer; bl type; c) model number; d) serial number; e) size: f) mass. A description of the handle covering shall be given. 7.5 Working conditions A detailed description of the working conditions as specified in the relevant part of IS0 8662 shall be given. 7.6 Signal processing Th
27、e type of signal integration in the spectrum analyser and the method of determining the weighted acceleration shall be stated. 7.7 Additional specifications All relevant details on the measurement set-up such as the size, type and mounting of the workpiece shall be stated. 7.6 Result The result shal
28、l be presented as a weighted value. For certain types of tools, octave band values shall also be reported when this is specified in the applicable part of IS0 8662. 4 Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=NASA Technical Standards 1/9
29、972545001 Not for Resale, 04/27/2007 08:38:50 MDTNo reproduction or networking permitted without license from IHS -,-,- IS0 6662-l : 1966 (E) UDC 634.1.06 : 621.9-162.4 Descriptors : vibration, tools, power-operated tools, portable equipment, portable electric machine tools, pneumatic equipment, tests, vibration tests. Price based on 4 pages Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=NASA Technical Standards 1/9972545001 Not for Resale, 04/27/2007 08:38:50 MDTNo reproduction or networking permitted without license from IHS -,-,-
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