CN111031418B - Sound insulation and amplification device for wall surface of force-excited reverberation box - Google Patents
Sound insulation and amplification device for wall surface of force-excited reverberation box Download PDFInfo
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- CN111031418B CN111031418B CN201911255320.0A CN201911255320A CN111031418B CN 111031418 B CN111031418 B CN 111031418B CN 201911255320 A CN201911255320 A CN 201911255320A CN 111031418 B CN111031418 B CN 111031418B
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; DEAF-AID SETS; PUBLIC ADDRESS SYSTEMS
- H04R1/00—Details of transducers, loudspeakers or microphones
- H04R1/02—Casings; Cabinets ; Supports therefor; Mountings therein
- H04R1/021—Casings; Cabinets ; Supports therefor; Mountings therein incorporating only one transducer
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; DEAF-AID SETS; PUBLIC ADDRESS SYSTEMS
- H04R1/00—Details of transducers, loudspeakers or microphones
- H04R1/02—Casings; Cabinets ; Supports therefor; Mountings therein
- H04R1/025—Arrangements for fixing loudspeaker transducers, e.g. in a box, furniture
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; DEAF-AID SETS; PUBLIC ADDRESS SYSTEMS
- H04R1/00—Details of transducers, loudspeakers or microphones
- H04R1/20—Arrangements for obtaining desired frequency or directional characteristics
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; DEAF-AID SETS; PUBLIC ADDRESS SYSTEMS
- H04R2201/00—Details of transducers, loudspeakers or microphones covered by H04R1/00 but not provided for in any of its subgroups
- H04R2201/02—Details casings, cabinets or mounting therein for transducers covered by H04R1/02 but not provided for in any of its subgroups
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- Engineering & Computer Science (AREA)
- Acoustics & Sound (AREA)
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- Measurement Of Mechanical Vibrations Or Ultrasonic Waves (AREA)
Abstract
The invention provides a sound insulation and amplification device for a wall surface of a force-excited reverberation box, which comprises a sound insulation cover, a first flange, an air suction valve, a wire outlet hole, a cylinder and a second flange, wherein the sound insulation cover is hemispherical, the first flange is arranged at the bottom of the sound insulation cover, a groove is formed in the first flange, the air suction valve is arranged on the sound insulation cover, the wire outlet hole is arranged on the sound insulation cover, the cylinder is positioned in the reverberation box, the axis of the cylinder is coincided with the force excitation direction, the second flange is arranged at the bottom of the cylinder, a groove is formed in the second flange, and a dimple and a through hole are formed from the middle section to the front end of the cylinder; the sound insulation and amplification device on the wall surface of the force excitation reverberation box utilizes the vacuum isolation force formed by the sound insulation cover to excite the noise radiated to the air by the source; an ultrasonic amplitude transformer-like mechanism consisting of cylinders is utilized to amplify the excitation action of a force excitation source, so that a higher sound pressure level is generated in a reverberation box, and the signal-to-noise ratio in the experimental test process is improved; the cavitation phenomenon that the cylinder is easy to occur in the strong vibration process is solved by utilizing the through holes and the pits at the front section in the cylinder.
Description
Technical Field
The invention relates to a sound insulation and amplification device for a wall surface of a force-excited reverberation box, and belongs to the field of acoustic measurement.
Background
The method for measuring the sound insulation performance of the acoustic covering layer under the low-frequency random incidence condition generally comprises the steps of placing a sound source in a reverberation box, utilizing the sound source to generate sound waves incident in all directions in the reverberation box, realizing the random incidence on the acoustic covering layer, receiving the sound waves transmitted by the acoustic covering layer by another reverberation box, and obtaining the sound insulation coefficient of the acoustic covering layer by a relative comparison method after respectively obtaining the spatial average sound pressure levels in the two reverberation boxes. Due to the fact that the cut-off frequency exists in the reverberation box, the lower limit frequency also exists in the sound insulation coefficient of the acoustic covering layer measured by the reverberation method. In order to break through the limit of the lower limit frequency, a method for testing the frequency by using wall surface point force as an excitation source and extending a reverberation box is developed. The method changes the acoustic impedance of the side wall of the reverberation box, so that the wall of the water-filled reverberation box is no longer the boundary condition of absolute softness (the inner side of the reverberation box is water, and the outer side of the reverberation box is air), and the test frequency of the reverberation box can be expanded. However, in the course of experimental tests carried out by this method, the following problems were also found:
firstly, because point force only excites one point of the side wall, the local vibration of the point is very strong, and the vibration of other parts is very weak, especially when the wall of the box is thin, so that cavitation phenomenon occurs, namely water molecules are separated from the wall, the radiation efficiency is reduced, and the sound pressure level in the reverberation box is low;
secondly, the force source itself generates strong single-frequency or wide-frequency noise, which is easily propagated through the aqueous medium in the reverberation box and then received by the hydrophones in the reverberation box on the other side. Although theoretically this noise results in a small amplitude of the hydrophone signal (the acoustic energy incident on the water from air is about one-thousandth of the acoustic energy incident directly on the water), it causes peaks in the spectrum. Since the sound insulation coefficient is a relative comparative quantity, these peaks can result in an overestimation of the sound insulation coefficient of the acoustic coating.
Thirdly, the force source only acts on the side wall of the reverberation box, and although the randomly incident sound wave can be generated in the reverberation box, the sound wave at the cut-off frequency of the reverberation box (the action of the sound source) is influenced by the sound energy cut-off in the reverberation box, so that the sound field is not uniform enough.
A method for analyzing and predicting noise in a high-speed train (application number: CN201610008123.9) discloses a method for analyzing and predicting noise in a high-speed train, which overcomes the problems that the existing method has frequency domain upper limit limitation and sound energy amplification is not considered yet.
Disclosure of Invention
The invention aims to provide a sound insulation and amplification device for a force-excited reverberation box wall.
The purpose of the invention is realized as follows: including setting up sound insulation cover and the cylinder in reverberation case wall both sides, the sound insulation is covered and is provided with first flange, is provided with the second flange on the cylinder, and sound insulation cover and cylindrical sealing connection are realized with the second flange to first flange, are provided with the exciter in the sound insulation cover, and the exciter is connected with the double-screw bolt, and the tip of double-screw bolt is connected with the cylinder after passing the reverberation case wall, is provided with bleeder valve and wire hole on the sound insulation cover.
The invention also includes such structural features:
1. the sound insulation cover is of a hemispherical structure.
2. Through holes are formed in the circumference from the middle section to the front end of the cylinder, a pit is arranged between each row of through holes, the generatrix of the cylinder changes in an exponential mode, and the diameter of the generatrix gradually decreases from the rear portion to the front portion of the cylinder.
3. The first flange and the second flange realize the sealed connection of the sound insulation cover and the cylinder, and the sealed connection refers to that: the first flange is connected with the second flange through a screw and a nut, grooves are formed in the contact surface of the first flange and the wall surface of the reverberation box and the contact surface of the second flange and the wall surface of the reverberation box, and sealing rings are arranged in the grooves.
Compared with the prior art, the invention has the beneficial effects that: firstly, the sound insulation cover is vacuum, so that single-frequency or broadband noise generated by the power source excitation equipment can be well isolated, and sound waves cannot be transmitted in vacuum; secondly, the cylinder is used as a cantilever beam structure and can vibrate after being subjected to the excitation effect transmitted by the force excitation source, and the other end of the cylinder is not limited and is a freely vibrating rod body which can be used as a transmission carrier of sound wave signals, so that the intensity of sound waves generated by the excitation side wall of the force source in the reverberation box is enhanced; thirdly, sound waves are radiated by the whole body of the cylinder during vibration, so that a sound field in the reverberation box is more uniform, and the sound field requirement during test below the lower limit frequency of the reverberation box is met; secondly, the side wall of the reverberation box and the cylinder form an ultrasonic amplitude transformer-like mechanism, and the cylinder can well amplify the force excitation action on the side wall, so that the signal-to-noise ratio of sound waves generated by the force source excitation side wall in the reverberation box is improved; finally, the cylinder is provided with the dimple and the through hole, the dimple can reduce the resistance between the cylinder and water molecules when the cylinder vibrates, and the through hole can enable the cylinder and water to be better coupled, so that the cavitation phenomenon caused by too large vibration amplitude of the force excitation source is avoided.
Drawings
FIG. 1 is an overall schematic view of a force-excited sound isolation and amplification device for the walls of a reverberant enclosure;
FIG. 2 is a fragmentary view of the upper half of a force-excited sound isolation and amplification device for the walls of a reverberant enclosure;
FIG. 3 is a flow chart of the design of a cylindrical configuration;
wherein, 1 is a sound insulation cover, 2 is a first flange, 3 is an air extraction valve, 4 is an outlet hole, 5 is a cylinder, 6 is a second flange, 7 is a fastener, 8 is an exciter, 9 is a stud and 10 is the wall surface of a reverberation box; the groove 21, the O-ring 22, the groove 23, the O-ring 24, the groove 25, the O-ring 26, the groove 61, the O-ring 62, the screw 71, the nut 72, the screw 73, and the nut 74.
Detailed Description
The present invention will be described in further detail with reference to the accompanying drawings and specific embodiments.
With reference to fig. 1 to 3, the sound insulation and amplification device for the wall surface of the force-excited reverberation box comprises a sound insulation cover 1, a first flange 2, an air extraction valve 3, an outlet hole 4, a column 5, a second flange 6, a fastener 7, an exciter 8, a stud 9 and a reverberation box wall surface 10; wherein, the first flange 2 is provided with a groove 21, an O-shaped ring 22, a groove 23, an O-shaped ring 24, a groove 25 and an O-shaped ring 26, the second flange 6 is provided with a groove 61 and an O-shaped ring 62, and the fastener 7 consists of a screw rod 71, a nut 72, a screw rod 73 and a nut 74; the sound insulation cover is hemispherical, a first flange is arranged at the bottom of the sound insulation cover, a groove is formed in the first flange, the air exhaust valve is arranged on the sound insulation cover, the wire outlet is arranged on the sound insulation cover, the cylinder is positioned in the reverberation box, the axis of the cylinder is coincided with the force excitation direction, a second flange is arranged at the bottom of the cylinder, the groove is formed in the second flange, and a dimple and a through hole are formed from the middle section to the front end of the cylinder; the first flange and the second flange are the same in size, and can be fastened on the side wall of the reverberation box by using a stud and a nut; placing an O-shaped ring in the groove of the first flange, and placing an O-shaped ring in the groove of the second flange; the interior of the sound insulation cover is vacuumized by using an air extraction valve;
the generatrix of the cylinder changes exponentially, and the diameter of the generatrix gradually decreases from the rear part to the front part of the cylinder; the fulcrum of the force excitation source is embedded into the cylinder in the form of a stud
The sound insulation cover 1 is made of a stainless steel plate through forging and pressing impact, the sound insulation cover can bear 0.1MPa of external pressure according to the design standard of a pressure vessel, and the thickness of the sound insulation cover 1 is 5mm in the embodiment;
the first flange 2 is made of stainless steel, a through hole is formed in the edge, a fastening piece 7 can be installed, a groove 21, a groove 23 and a groove 26 are respectively formed in the first flange, an O-shaped ring 22 is placed in the groove 21, an O-shaped ring 24 is placed in the groove 23, an O-shaped ring 26 is placed in the groove 25, and the first flange 2 is welded on the edge of the sound insulation cover 1;
the air extraction valve 3 is a ball valve and is welded on the surface of the sound insulation cover 1, a vacuum pump is used for extracting air in the air extraction valve 3, when the pressure is close to 0MPa, the air extraction valve 3 is closed, and a vacuum state is formed in the sound insulation cover 1 and is used for reducing broadband radiation noise generated by the exciter 8;
the air exhaust hole 4 is in a stuffing box form and is used for hermetically sealing a cable connected with the exciter 8;
the cylinder 5 is made of stainless steel; similar to the design method of the amplitude transformer in ultrasonic processing, but is different from the amplitude transformer in the ultrasonic processing in that: on one hand, the front end of the cylinder is provided with the through holes and the dimples are distributed, so that the coupling effect between the cylinder and water is enhanced; on the other hand, the characteristic impedance of the cylinder is slightly different from that of water, and the front end of the cylinder cannot focus very high vibration energy like an ultrasonic horn. In addition, in the embodiment, the front end of the cylinder is provided with the through hole and the dimple, and it is extremely difficult to analyze and calculate the amplification factor of the cylinder under the condition of force source excitation, so that a model of the wall surface of the point force excitation reverberation box and the cylinder are respectively established, and characteristic parameters of the cylinder, such as length, bus and the like, are determined by relatively comparing the spatial average sound pressure level in the reverberation box under the conditions of the two excitation models, and the flow chart is shown in fig. 3;
the second flange 6 is made of stainless steel, a groove 61 is formed in the edge of the second flange, an O-shaped ring 62 can be placed in the groove, and the second flange 6 is welded to the edge of the cylinder 5;
the fastener 7 is composed of a screw 71, a nut 72, a screw 73 and a nut 74 and is used for fixing the first flange 2 and the second flange 6;
the exciter 8 is a rare earth magnetostrictive transducer and can realize excitation on the wall surface 10 of the reverberation box under the drive of a sinusoidal signal;
the stud 9 is a common stud, penetrates through the wall surface 10 of the reverberation box, and one end of the stud 9 is screwed into the cylinder 5; the other end of the stud 9 is screwed into the exciter 8, and the top surface of the exciter 8 is tightly attached to the wall surface 10 of the reverberation box, so that the function of applying a force excitation signal of the exciter 8 to the cylinder 5 is realized, and the excitation function of the wall surface 10 of the reverberation box is also realized;
the reverberation box wall surface 10 is a wall surface of the reverberation box, and random incidence of a sound field in the reverberation box can be realized by exciting the wall surface;
after the appearance of the cylinder 5 is designed for many times and tested by experiments, the spatial average sound pressure level in the reverberation box without the cylinder 5 is 112dB, and the spatial average sound pressure level in the reverberation box after the cylinder 5 is installed is 119 dB.
In summary, the invention provides a sound insulation and amplification device for a wall surface of a force-excited reverberation box, which comprises a sound insulation cover, a first flange, an air extraction valve, a wire outlet hole, a cylinder and a second flange, wherein the sound insulation cover is hemispherical, the first flange is arranged at the bottom of the sound insulation cover, a groove is formed in the first flange, the air extraction valve is arranged on the sound insulation cover, the wire outlet hole is arranged on the sound insulation cover, the cylinder is positioned in the reverberation box, the axis of the cylinder is coincided with the force excitation direction, the second flange is arranged at the bottom of the cylinder, the groove is formed in the second flange, and a dimple and a through hole are formed from the middle section to the front end of; the sound insulation and amplification device on the wall surface of the force excitation reverberation box utilizes the vacuum isolation force formed by the sound insulation cover to excite the noise radiated to the air by the source; an ultrasonic amplitude transformer-like mechanism consisting of cylinders is utilized to amplify the excitation action of a force excitation source, so that a higher sound pressure level is generated in a reverberation box, and the signal-to-noise ratio in the experimental test process is improved; the cavitation phenomenon that the cylinder is easy to occur in the strong vibration process is solved by utilizing the through holes and the pits at the front section in the cylinder.
Claims (3)
1. A sound insulation and amplification device of a force-excited reverberation box wall is characterized in that: the sound insulation cover is provided with a first flange, the cylinder is provided with a second flange, the first flange and the second flange are in sealed connection with each other, an exciter is arranged in the sound insulation cover and connected with a stud, the end part of the stud penetrates through the wall surface of the reverberation box and then is connected with the cylinder, and the sound insulation cover is provided with an air exhaust valve and a wire outlet hole; through holes are formed in the circumference from the middle section to the front end of the cylinder, a pit is arranged between each row of through holes, the generatrix of the cylinder changes in an exponential mode, and the diameter of the generatrix gradually decreases from the rear portion to the front portion of the cylinder.
2. The sound insulation and amplification device for a force-excited reverberant enclosure wall of claim 1, further comprising: the sound insulation cover is of a hemispherical structure.
3. A force activated sound insulation and amplification device for a wall of a reverberant enclosure according to claim 1 or 2, characterised in that: the first flange and the second flange realize the sealed connection of the sound insulation cover and the cylinder, and the sealed connection refers to that: the first flange is connected with the second flange through a screw and a nut, grooves are formed in the contact surface of the first flange and the wall surface of the reverberation box and the contact surface of the second flange and the wall surface of the reverberation box, and sealing rings are arranged in the grooves.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201911255320.0A CN111031418B (en) | 2019-12-10 | 2019-12-10 | Sound insulation and amplification device for wall surface of force-excited reverberation box |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201911255320.0A CN111031418B (en) | 2019-12-10 | 2019-12-10 | Sound insulation and amplification device for wall surface of force-excited reverberation box |
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| Publication Number | Publication Date |
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| CN111031418A CN111031418A (en) | 2020-04-17 |
| CN111031418B true CN111031418B (en) | 2021-04-06 |
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Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2013252008A (en) * | 2012-06-01 | 2013-12-12 | Ihi Corp | Sound insulation structure |
| CN207382585U (en) * | 2017-11-14 | 2018-05-18 | 珠海市精实测控技术有限公司 | Sound proof box performance testing device |
| CN109187758A (en) * | 2018-09-06 | 2019-01-11 | 华南理工大学 | A kind of automobile front wall sound insulation tooling and its measurement method |
| CN109580257A (en) * | 2019-01-24 | 2019-04-05 | 中汽研（天津）汽车工程研究院有限公司 | A kind of rear axle rack vibration noise measuring system |
-
2019
- 2019-12-10 CN CN201911255320.0A patent/CN111031418B/en active Active
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2013252008A (en) * | 2012-06-01 | 2013-12-12 | Ihi Corp | Sound insulation structure |
| CN207382585U (en) * | 2017-11-14 | 2018-05-18 | 珠海市精实测控技术有限公司 | Sound proof box performance testing device |
| CN109187758A (en) * | 2018-09-06 | 2019-01-11 | 华南理工大学 | A kind of automobile front wall sound insulation tooling and its measurement method |
| CN109580257A (en) * | 2019-01-24 | 2019-04-05 | 中汽研（天津）汽车工程研究院有限公司 | A kind of rear axle rack vibration noise measuring system |
Non-Patent Citations (2)
| Title |
|---|
| 无规入射下声学覆盖层隔声性能测量研究;刘丛宇等;《声学技术》;20190921;第38卷(第5期);全文 * |
| 点声源入射下无限大平板的隔声;史晓峰等;《声学学报》;20180515;第33卷(第3期);全文 * |
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