CN111983033A - Acoustic material high-frequency noise reduction performance testing equipment and evaluation method - Google Patents
Acoustic material high-frequency noise reduction performance testing equipment and evaluation method Download PDFInfo
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- CN111983033A CN111983033A CN202010848904.5A CN202010848904A CN111983033A CN 111983033 A CN111983033 A CN 111983033A CN 202010848904 A CN202010848904 A CN 202010848904A CN 111983033 A CN111983033 A CN 111983033A
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- 238000012360 testing method Methods 0.000 title claims abstract description 50
- 239000012814 acoustic material Substances 0.000 title claims abstract description 39
- 238000011156 evaluation Methods 0.000 title description 9
- 238000000034 method Methods 0.000 claims abstract description 6
- 229920000742 Cotton Polymers 0.000 claims abstract description 5
- 238000011056 performance test Methods 0.000 claims description 11
- 239000012528 membrane Substances 0.000 claims description 3
- 239000010802 sludge Substances 0.000 claims description 3
- 238000007789 sealing Methods 0.000 claims description 2
- 238000010521 absorption reaction Methods 0.000 abstract description 3
- 238000013461 design Methods 0.000 abstract description 2
- 239000010410 layer Substances 0.000 description 13
- 239000000463 material Substances 0.000 description 10
- 238000010586 diagram Methods 0.000 description 3
- 238000009413 insulation Methods 0.000 description 3
- 238000011161 development Methods 0.000 description 2
- 238000005259 measurement Methods 0.000 description 2
- 229910000831 Steel Inorganic materials 0.000 description 1
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 1
- 229910052782 aluminium Inorganic materials 0.000 description 1
- 238000005253 cladding Methods 0.000 description 1
- 239000011248 coating agent Substances 0.000 description 1
- 238000000576 coating method Methods 0.000 description 1
- 238000003780 insertion Methods 0.000 description 1
- 230000037431 insertion Effects 0.000 description 1
- 238000002955 isolation Methods 0.000 description 1
- 230000000873 masking effect Effects 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000012856 packing Methods 0.000 description 1
- 230000005855 radiation Effects 0.000 description 1
- 238000004088 simulation Methods 0.000 description 1
- 239000002356 single layer Substances 0.000 description 1
- 239000010959 steel Substances 0.000 description 1
- 238000012795 verification Methods 0.000 description 1
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N29/00—Investigating or analysing materials by the use of ultrasonic, sonic or infrasonic waves; Visualisation of the interior of objects by transmitting ultrasonic or sonic waves through the object
- G01N29/04—Analysing solids
- G01N29/11—Analysing solids by measuring attenuation of acoustic waves
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N2291/00—Indexing codes associated with group G01N29/00
- G01N2291/02—Indexing codes associated with the analysed material
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Abstract
The invention discloses a device and a method for testing the high-frequency noise reduction performance of an acoustic material, wherein the device comprises a noise reduction box, a high-frequency loudspeaker, a first microphone and a second microphone, the noise reduction box comprises an inner layer box body and an outer layer box body, the outer layer box body is sleeved outside the inner layer box body, sound absorption cotton is filled between the inner layer box body and the outer layer box body, a front panel of the inner layer box body is provided with an opening, a positioning step is arranged on the edge of the opening, a test sample piece is placed on the positioning step and closes the opening to form a sound cavity, the high-frequency loudspeaker is arranged in the sound cavity and fixed on a back panel of the inner layer box body, the first microphone is arranged in the sound cavity and fixed on a side panel of the inner layer box body to receive the sound pressure level on the inner side of the test sample piece, and the second microphone is arranged outside. The test equipment designs a noise reduction box with a built-in high-frequency sound source and a built-in microphone so as to measure the high-frequency noise reduction amount of the acoustic material. The invention also correspondingly discloses a method for evaluating the high-frequency noise reduction performance of the acoustic material.
Description
Technical Field
The invention relates to the technical field of acoustic material performance evaluation, in particular to acoustic material high-frequency noise reduction performance testing equipment and an evaluation method.
Background
In recent years, new energy automobiles are developed vigorously, the sales volume of new energy automobiles in various countries is increased year by year, the total sales volume of new energy automobiles in the world in 2019 is nearly 439 thousands, and pure electric automobiles account for 74%. In recent two years, the sales volume of new energy automobiles in China is at the top of the world, the sales volume accounts for 29% of the global sales volume in 2019, and the acceptance of electric automobiles by consumers is higher and higher.
Compared with the traditional automobile, the electric automobile has no masking effect of engine noise, so that the feeling of the noise in the automobile to drivers and passengers is more complicated and more prominent, wherein the high-frequency noise of the rotating radiation of the motor is more prominent. To address the high frequency noise problem of motors, all electric vehicle manufacturers have focused on and dedicated to acoustic studies of motor cladding. However, there is no accurate and rapid evaluation method in terms of the high-frequency noise reduction performance of the motor coating material at present.
Disclosure of Invention
The invention aims to provide a device for testing the high-frequency noise reduction performance of an acoustic material, which is convenient for simulating the environment and the state of a motor coated in an electric vehicle so as to test the performance of the acoustic material.
The invention also aims to provide an acoustic material high-frequency noise reduction performance evaluation method, which is used for evaluating the high-frequency noise reduction performance of the acoustic material coated by the motor by testing the acoustic material in a narrow space by simulating the high-frequency characteristics of the motor noise, so as to screen out a material scheme with high-frequency acoustic performance.
In order to achieve the purpose, the invention adopts the following technical scheme:
the utility model provides an acoustic material high frequency noise reduction capability test equipment, it includes the noise reduction box, high frequency speaker, first microphone and second microphone, the noise reduction box includes inlayer box and outer box, outer box cover is established outside the inlayer box, and it has the sound cotton to inhale between the two packing, the front board opening of inlayer box, and be provided with the location step on the opening border, test sample spare is placed on the location step and is sealed the opening, thereby form the acoustic cavity, high frequency speaker sets up in the acoustic cavity and fixes on the backplate of inlayer box, first microphone sets up in the acoustic cavity and fixes on the side board of inlayer box, thereby receive the inboard sound pressure level of test sample spare, the second microphone sets up outside the acoustic cavity, a sound pressure level outside the test sample spare is used for receiving.
Preferably, the tweeter is located in the center of the back panel of the inner housing.
Preferably, the first microphones are provided in two, symmetrically located on the central axis of the left and right side panels of the inner case, and the average sound pressure level of the two first microphones is taken as the sound pressure level of the inner side.
Preferably, the receiving ports of the two first microphones are spaced apart by 10 cm.
Preferably, the receiving port of the second microphone is located on the same axis as the tweeter, and the second microphone is no more than 3cm from the outer surface of the test piece.
Preferably, the opening border of inlayer box turns over an extension and surpasss outer box, and is provided with on the opening border and walks the line hole, has seted up the mounting hole corresponding first microphone on the inlayer box, and the power cord of first microphone penetrates between outer box and the inlayer box from the mounting hole, walks the line hole from at last and wears out.
Preferably, the positioning step and the test sample piece are sealed by oil sludge.
Preferably, the high-frequency loudspeaker is a circular loudspeaker adopting a dome-shaped vibrating membrane, and the sound source frequency range of the high-frequency loudspeaker is 2.5-25 kHz.
A method for evaluating the high-frequency noise reduction performance of an acoustic material adopts the high-frequency noise reduction performance test equipment of the acoustic material, a test sample is placed on a positioning step of a noise reduction box, and the sound pressure level of the interior of the noise reduction box measured by a first microphone is SPLInner partThe sound pressure level outside the noise reduction box measured by the second microphone is SPLOuter coverAnd testing the high-frequency noise reduction quantity NR ═ SPL of the sample pieceInner part-SPLOuter cover。
In particular, when more than one first microphone is arranged inside the noise reduction box, the sound pressure level inside the noise reduction box is the average sound pressure level of the first microphones, i.e. the noise reduction box is a loudspeaker
High frequency noise reduction of test sampleMeasurement of
Compared with the prior art, the acoustic material high-frequency noise reduction performance testing equipment and the acoustic material high-frequency noise reduction performance evaluating method have the advantages that the cubic noise reduction box with the built-in high-frequency sound source and the built-in microphone is designed, different acoustic materials are placed on the noise reduction table and sealed, medium-high frequency noise reduction measurement can be conducted on the material scheme in a targeted mode, the noise reduction box in a narrow space reduces loss of the equipment to high-frequency sound energy, more accurate testing data can be obtained, the acoustic materials are tested in the narrow space through simulation of the high-frequency characteristic of motor noise, the material scheme with the high-frequency acoustic performance is screened out, and development of the high-frequency noise reduction materials is facilitated.
Drawings
FIG. 1 is a schematic diagram of an acoustic material high-frequency noise reduction performance testing apparatus provided by an embodiment of the present invention;
FIG. 2 is a schematic diagram of an internal structure of a noise reduction box in the acoustic material high-frequency noise reduction performance testing apparatus provided by the embodiment of the invention;
fig. 3 is a schematic structural diagram of a noise reduction box in the acoustic material high-frequency noise reduction performance test device provided by the embodiment of the invention.
Detailed Description
The technical scheme of the invention is further explained by the specific implementation mode in combination with the attached drawings.
Referring to fig. 1 to 3, the present embodiment provides an apparatus for testing high frequency noise reduction performance of an acoustic material, which includes a noise reduction box 1, a high frequency speaker 2, a first microphone 3 and a second microphone 4.
The noise reduction box 1 comprises an inner-layer box body 11 and an outer-layer box body 12, the outer-layer box body 12 is sleeved outside the inner-layer box body 11, sound-absorbing cotton is filled between the inner-layer box body and the outer-layer box body, a front panel opening of the inner-layer box body 11 is provided with a positioning step 13 on an opening edge 16, and a test sample piece 5 is placed on the positioning step 13 and closes the opening, so that a sound cavity is formed, and a gap between the positioning step 13 and the test sample piece 5 is preferably sealed by oil sludge. Compared with a single-layer uniform material plate with the same surface density, the structure has better medium-high frequency sound insulation performance, and meanwhile, the sound absorption layer formed by the sound absorption cotton can also avoid the plate resonance property to ensure the uniformity of an in-box sound field, so that the isolation performance of the box body to high-frequency sound energy is integrally improved.
On the basis of meeting certain sound insulation performance of the box body, plates made of other materials, such as aluminum plates, plastic plates and the like, can be used on the inner wall surface and the outer wall surface of the box body. The noise reduction box 1 can also test the noise reduction performance of the combination of the steel plate and the sample piece, and further can calculate the insertion loss of the test sample piece 5.
The tweeter 2 is disposed in the acoustic cavity and fixed to the rear panel of the inner housing 11, and most preferably, the tweeter 2 is located at the center of the rear panel of the inner housing 11. The high-frequency loudspeaker 2 is a circular loudspeaker adopting a dome-shaped vibrating membrane, and the sound source frequency range is 2.5-25 kHz. The loudspeaker is suitable for simulating high-frequency noise generated by a motor when an electric vehicle runs at a high speed, the wavelength of the high-frequency sound wave is short, and the high-frequency sound energy is easy to lose in a larger space, so that the distribution uniformity and stability of the high-frequency sound energy can be ensured in the narrow space of the noise reduction box 1 during testing.
The first microphones 3 are disposed in the sound cavity and fixed on the side panel of the inner case 11 so as to receive the sound pressure level inside the test sample 5, and here, the two first microphones 3 are not limited to this, and the two first microphones 3 are symmetrically disposed on the central axis of the left and right side panels of the inner case 11, and the average sound pressure level of the two first microphones 3 is used as the sound pressure level inside. As the high-frequency sound wave has stronger directivity, the SPL data of the high-frequency sound obtained by testing in the range of 5cm near the central axis of the front and the rear surfaces of the box body is most accurate after verification, so that the distance from the receiving port of each first microphone 3 to the high-frequency loudspeaker 2 is set to be 5cm, and the distance between the receiving ports of the two first microphones 3 is 10cm, thereby ensuring that the inner microphones can measure accurate average sound pressure level data.
The second microphone 4 is disposed outside the acoustic cavity and configured to receive the sound pressure level outside the test sample 5, preferably, a receiving port of the second microphone 4 is located on the same axis as the tweeter 2, and a distance between the second microphone 4 and the outer surface of the test sample 5 is not greater than 3cm, so that a high-frequency sound energy loss caused by an excessively long distance can be avoided within a distance range.
Further, the opening border 16 of the inner-layer box body 11 is turned over and extends and exceeds the outer-layer box body 12, the opening border 16 is provided with a wire-passing hole 14, the inner-layer box body 11 is provided with a mounting hole 15 corresponding to the first microphone 3, a power line of the first microphone 3 penetrates between the outer-layer box body 12 and the inner-layer box body 11 from the mounting hole 15, and finally the wire-passing hole 14 penetrates out.
In addition, the embodiment also provides an acoustic material high-frequency noise reduction performance evaluation method, which adopts the acoustic material high-frequency noise reduction performance test equipment, and by placing the test sample 5 on the positioning step 13 of the noise reduction box 1, which is similar to an embedded structure of a sound insulation window test, and simultaneously sealing the edge of the test sample, the sound pressure level inside the noise reduction box 1 measured by the first microphone 3 is SPLInner partThe sound pressure level outside the noise reduction box 1 measured by the second microphone 4 is SPLOuter coverThen, the high frequency noise reduction NR of the test sample 5 is SPLInner part-SPLOuter coverI.e., as an evaluation value of the high-frequency noise reduction performance of the test sample 5.
In particular, when more than one first microphone 3 is arranged inside the noise reduction box 1, the sound pressure level inside the noise reduction box 1 is the average sound pressure level of each first microphone 3, i.e. the sound pressure level inside the noise reduction box 1 is
The high frequency noise reduction of the test piece 5 is measured
In conclusion, the acoustic material high-frequency noise reduction performance test equipment and the evaluation method design the cubic noise reduction box with the built-in high-frequency sound source and the built-in microphone, different acoustic materials are placed on the noise reduction table and sealed, medium-high frequency noise reduction measurement can be conducted on the material scheme in a targeted manner, the noise reduction box in a narrow space reduces the loss of the equipment to high-frequency sound energy, more accurate test data can be obtained, the acoustic materials are tested in the narrow space by simulating the high-frequency characteristic of motor noise, and the material scheme with high-frequency acoustic performance is screened out, and the development of the high-frequency noise reduction materials is facilitated.
The foregoing embodiments are merely illustrative of the principles and features of this invention, which is not limited to the above-described embodiments, but is capable of various modifications and changes without departing from the spirit and scope of the invention, which are intended to be within the scope of the appended claims. The scope of the invention is defined by the appended claims and equivalents thereof.
Claims (10)
1. The utility model provides an acoustic material high frequency noise reduction capability test equipment, its characterized in that, is including noise reduction box, tweeter, first microphone and second microphone, noise reduction box includes inlayer box and outer box, outer box cover is established outside the inlayer box, and it has the sound of inhaling cotton to fill between the two, the front board opening of inlayer box, and be provided with the location step on the opening border, test sample spare is placed on the location step and seals the opening to form the sound chamber, tweeter set up in the sound chamber and fix on the backplate of inlayer box, first microphone set up in on the side board of fixed inlayer box in the sound chamber to receive the inboard sound pressure level of test sample spare, the second microphone set up in outside the sound chamber for receive the sound pressure level in the test sample spare outside.
2. The acoustic material high frequency noise reduction performance test apparatus according to claim 1, wherein: the high-frequency loudspeaker is positioned in the center of the back panel of the inner-layer box body.
3. The acoustic material high frequency noise reduction performance test apparatus according to claim 1, wherein: the two first microphones are symmetrically arranged on the central shaft of the left side panel and the right side panel of the inner layer box body, and the average sound pressure level of the two first microphones is used as the sound pressure level of the inner side.
4. The acoustic material high frequency noise reduction performance test apparatus according to claim 1, wherein: the receiving ports of the two first microphones are spaced by 10 cm.
5. The acoustic material high frequency noise reduction performance test apparatus according to claim 1, wherein: the receiving port of the second microphone is located on the same axis as the tweeter and the second microphone is no more than 3cm from the outer surface of the test piece.
6. The acoustic material high frequency noise reduction performance test apparatus according to claim 1, wherein: the opening border of inlayer box turns over to roll over and extends and surpass outer box, and is provided with on the opening border and walks the line hole, the mounting hole has been seted up to corresponding first microphone on the inlayer box, the power cord of first microphone certainly the mounting hole penetrates outer box with between the inlayer box, at last certainly walk the line hole and wear out.
7. The acoustic material high frequency noise reduction performance test apparatus according to claim 1, wherein: and oil sludge is adopted for sealing between the positioning step and the test sample piece.
8. The acoustic material high frequency noise reduction performance test apparatus according to claim 1, wherein: the high-frequency loudspeaker is a circular loudspeaker adopting a dome-shaped vibrating membrane, and the sound source frequency range of the high-frequency loudspeaker is 2.5-25 kHz.
9. A method for evaluating the high-frequency noise reduction performance of an acoustic material is characterized in that the acoustic material high-frequency noise reduction performance testing equipment according to any one of claims 1 to 8 is adopted, a test sample is placed on a positioning step of a noise reduction box, and the sound pressure level of the interior of the noise reduction box measured by a first microphone is SPLInner partThe sound pressure level outside the noise reduction box measured by the second microphone is SPLOuter coverAnd testing the high-frequency noise reduction quantity NR ═ SPL of the sample pieceInner part-SPLOuter cover。
10. According to claimThe method for evaluating the high-frequency noise reduction performance of an acoustic material according to claim 9, characterized by: when more than one first microphone is arranged inside the noise reduction box, the sound pressure level inside the noise reduction box is the average sound pressure level of each first microphone, i.e. the sound pressure level of the noise reduction box is the average sound pressure level of the first microphones
The high frequency noise reduction of the test sample
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN112857553A (en) * | 2021-02-22 | 2021-05-28 | 同济大学 | Noise reduction performance experimental device and method for acoustic cavity of coupling film nonlinear energy trap |
| CN115047076A (en) * | 2022-08-17 | 2022-09-13 | 歌尔股份有限公司 | Sound insulation box performance test method |
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Application publication date: 20201124 |