CN112728275A - Non-single low-frequency ultra-open ventilation adjustable sound absorption unit - Google Patents
Non-single low-frequency ultra-open ventilation adjustable sound absorption unit Download PDFInfo
- Publication number
- CN112728275A CN112728275A CN202011512169.7A CN202011512169A CN112728275A CN 112728275 A CN112728275 A CN 112728275A CN 202011512169 A CN202011512169 A CN 202011512169A CN 112728275 A CN112728275 A CN 112728275A
- Authority
- CN
- China
- Prior art keywords
- adjustable
- cavity
- sound absorption
- frames
- frame
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
Images
Classifications
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16L—PIPES; JOINTS OR FITTINGS FOR PIPES; SUPPORTS FOR PIPES, CABLES OR PROTECTIVE TUBING; MEANS FOR THERMAL INSULATION IN GENERAL
- F16L55/00—Devices or appurtenances for use in, or in connection with, pipes or pipe systems
- F16L55/02—Energy absorbers; Noise absorbers
- F16L55/033—Noise absorbers
Landscapes
- Engineering & Computer Science (AREA)
- General Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Soundproofing, Sound Blocking, And Sound Damping (AREA)
Abstract
The invention discloses a non-single low-frequency ultra-open ventilation adjustable sound absorption unit, wherein an inner cavity of each sub-tube resonant cavity is defined by a fixed inner frame and a left pulling adjustable inner frame and a right pulling adjustable inner frame, an outer cavity of each sub-tube resonant cavity is defined by a fixed outer frame and a left pulling adjustable outer frame and a right pulling adjustable outer frame, the fixed inner frame and the two pulling adjustable inner frames are respectively connected through a similar injector structure, the pulling adjustable inner frames are fixedly connected with the corresponding pulling adjustable outer frames through pull rods, the pull rods extend out of the adjustable outer frames, the pull rods pull the adjustable inner frames forwards and backwards to move synchronously with the adjustable outer frames, and the sizes of the inner cavity and the outer cavities. The adjustable inner frame and the adjustable outer frame are pulled to move synchronously through the pull rod, the sizes of the inner cavity and the outer cavity can be adjusted simultaneously, the same sound absorption unit is adjusted to adapt to sound absorption and noise reduction of different frequencies, and the defect that the conventional acoustic metamaterial can only be designed with a specific structure to absorb noise of a single frequency is overcome.
Description
Technical Field
The invention relates to the technical field of non-single-frequency low-frequency noise treatment, in particular to a sound absorption unit with super-open ventilation adjustable sound absorption performance, which is suitable for non-single-frequency low-frequency noise treatment.
Background
Noise cancellation plays an important role in our daily lives, especially for low frequency noise of non-unity frequency (between 50 and 1000 Hz), and currently achieving effective sound absorption of low frequency noise is still a very difficult task due to its high penetration force.
The national intellectual property office announces an ultra-open type efficient ventilation sound absorption unit and a sound absorber (ZLCN201911128961.X) on 21.2.2020, two weakly-coupled branch pipe resonant cavities which are in a shape of a Chinese character 'hui' respectively are adopted, a sound absorption channel formed by a cover plate and a plurality of horizontal sound absorption narrow slits in a shape of a Chinese character 'yi' are combined, each sound absorption unit forms a rigid loss oscillator similar to a spring and is used for being installed in an open type airflow channel with a larger cross section, efficient absorption and ventilation of low frequency can be achieved, and the technical bottleneck that the existing acoustic metamaterial needs to be completely sealed to flow channels to achieve perfect sound absorption but cannot meet ventilation is overcome. The sound absorption unit can perfectly absorb the low-frequency noise with fixed single frequency, and the sound absorption effect of the variable-frequency low-frequency noise with non-single frequency is greatly reduced. In the practical application process, the noise frequency is changed, and for low-frequency noise with different frequencies, sound absorption units with different sizes and specifications are required to be equipped.
Disclosure of Invention
The invention aims to provide an ultra-open type ventilation sound absorption unit special for low-frequency noise treatment, which can realize the high-efficiency absorption and ventilation of various low-frequency noises by adjusting so as to overcome the defect that the existing ultra-open type high-efficiency ventilation sound absorption unit can only absorb single low-frequency noise.
The technical scheme adopted by the invention is as follows: a non-single low-frequency ultra-open ventilation adjustable sound absorption unit comprises a first branch tube resonant cavity and a second branch tube resonant cavity which are symmetrically arranged in front and back side by side, wherein each branch tube resonant cavity consists of an inner cavity and an outer cavity and is integrally in a shape like a Chinese character 'hui', and the upper side and the lower side of each of the first branch tube resonant cavity and the second branch tube resonant cavity are respectively provided with a cover plate so as to enclose a sound absorption channel; the middle part of the front side wall of the outer cavity, the middle part of the front side wall of the inner cavity and the middle part of the rear side wall of the outer cavity of the first branched pipe resonant cavity are respectively provided with a linear sound absorption narrow slit with the same height as the branched pipe resonant cavity;
the inner cavity of each sub-tube resonant cavity is defined by a fixed inner frame and a left pulling adjustable inner frame and a right pulling adjustable inner frame, the outer cavity of each sub-tube resonant cavity is defined by a fixed outer frame and a left pulling adjustable outer frame and a right pulling adjustable outer frame, the fixed inner frame and the two pulling adjustable inner frames are respectively connected through a similar injector structure, the pulling adjustable inner frames are fixedly connected with the corresponding pulling adjustable outer frames through pull rods, the pull rods stretch out of the adjustable outer frames, the pulling adjustable inner frames and the adjustable outer frames move synchronously through the pull rods in a front-back pulling mode, and the sizes of the inner cavity and the outer.
Preferably, the fixed inner frame and the pulling adjustable inner frame are respectively in a 'U' shape, the fixed inner frames of the two sub-tube resonant cavities are arranged close to and back to each other, inner legs of the two pulling adjustable inner frames of the same sub-tube resonant cavity are arranged at intervals to just form a 'straight' sound absorption narrow slit, and an outer leg of each pulling adjustable frame is provided with a fork port for inserting a corresponding leg of the fixed frame or a leg of the fixed frame is provided with a fork port for inserting an outer leg of the corresponding pulling adjustable frame, so that the similar injector structure is formed; the fixed outer frames of the two sub-tube resonant cavities are integrally arranged and integrally in an H shape, a horizontal bar in the middle is provided with a linear sound absorption narrow slit, and two pulling adjustable outer frames of the same sub-tube resonant cavity are arranged at intervals to just form the linear sound absorption narrow slit. The U-shaped structure and the fork leg insertion structure are adopted, so that the adjustment and the guiding are facilitated, the movement stability is ensured, and the left part and the right part are adopted for the adjusting frame, so that a linear sound absorption narrow slit is formed skillfully; the fixed frame of two tubulation resonant cavities sets up as an organic whole, and the wholeness is stronger, and stability is higher in the accommodation process.
Preferably, the inner legs of the pulling adjustable inner frames are spaced from the edge of the U-shaped bottom plate by a certain distance so as to increase the distance between the inner legs of the two pulling adjustable inner frames, and the width of the linear sound absorption narrow gaps formed at the positions is larger than that of the rest linear sound absorption narrow gaps. The inner cavity of the sub-tube resonant cavity is the core part of the sound absorption unit and plays a main role in attenuating air flow, the air flow passes through the narrow slits and then passes through the wide slits before entering the inner cavity of each sub-tube resonant cavity for transition buffering, and the sound absorption effect is obviously enhanced.
Preferably, the tail end of the pull rod is connected with a self-adaptive motor, the pull rod is driven by the self-adaptive motor to move back and forth, and the self-adaptive motors on the two sides of the first and second column tube resonant cavities synchronously drive the corresponding pull rods and pull the pull rods for the same distance. The number of self-adaptive motors is reduced, and the cost is reduced; and can ensure synchronous movement, and is more convenient for adjustment and control.
The invention has the beneficial effects that: the inner cavity of each sub-tube resonant cavity of the non-single low-frequency ultra-open ventilation adjustable sound absorption unit is defined by a fixed inner frame and a left pulling adjustable inner frame and a right pulling adjustable inner frame, the outer cavity of each sub-tube resonant cavity is defined by a fixed outer frame and a left pulling adjustable outer frame and a right pulling adjustable outer frame, the fixed inner frame and the two pulling adjustable inner frames are respectively connected through a similar injector structure, the adjustable inner frames and the adjustable outer frames are pulled forwards and backwards through a pull rod to move synchronously, the sizes of the inner cavity and the outer cavity can be adjusted simultaneously, the sound absorption and the noise reduction of the same sound absorption unit adapting to different frequencies through adjustment are realized, and the defect that the existing acoustic metamaterial can only be designed.
Drawings
Fig. 1 is a perspective view of a non-unitary low frequency ultra-open ventilation adjustable sound absorbing unit.
Fig. 2 is a top view (two adjustment limit positions) of a non-unitary low frequency ultra-open ventilation adjustable sound absorbing unit.
Fig. 3 is a cross-sectional view of a non-unitary low frequency ultra-open ventilation adjustable sound absorbing unit installed in an airflow channel.
Fig. 4 is a circuit block diagram of an adaptive identification system.
Fig. 5 is a circuit connection diagram of an adaptive identification system.
Detailed Description
The invention will be further illustrated by the following examples in conjunction with the accompanying drawings:
referring to fig. 1 and 2, a non-single low-frequency ultra-open ventilation adjustable sound absorption unit is composed of a first shell-and-tube resonator 1 and a second shell-and-tube resonator 2, which are symmetrically arranged in front and back in parallel. Each sub-tube resonant cavity is composed of an inner cavity and an outer cavity and is in a shape of a Chinese character 'hui'. The left and right sides of the first and second column resonator cavities 1 and 2 are equipped with cover plates (not shown in the figure), so that a sound absorption channel is formed between the inner frame and the outer frame.
The first shell front side wall middle part, the first shell front side wall middle part and the first shell rear side wall middle part of the first shell resonant cavity 1, and the second shell front side wall middle part, the first shell rear side wall middle part and the first shell rear side wall middle part of the second shell resonant cavity 2 are respectively provided with a "straight" sound absorption narrow slit having the same height as the shell resonant cavity, which is the same as the super-open ventilation sound absorption unit introduced in the background art, and the description thereof is omitted.
The difference lies in that: the inner cavity of each sub-column tube resonant cavity is enclosed by a fixed inner frame 3 and a left pulling adjustable inner frame 4 and a right pulling adjustable inner frame 4. The outer cavity of each sub-tube resonant cavity is surrounded by a fixed outer frame 5 and a left pulling adjustable outer frame 6 and a right pulling adjustable outer frame 6. The fixed inner frame 3 and the two pulling adjustable inner frames 4 are respectively connected through a similar injector structure, the pulling adjustable inner frames 4 are fixedly connected with the corresponding pulling adjustable outer frames 6 through pull rods 7, and the pull rods 7 extend out of the adjustable outer frames 6. The adjustable inner frame 4 and the adjustable outer frame 6 are pulled back and forth by the pull rod 7 to move synchronously, so that the sizes of the inner cavity and the outer cavity can be adjusted simultaneously.
Preferably, the fixed inner frame 3 and the pulling adjustable inner frame 4 are respectively in a U shape, and the fixed inner frames 3 of the two separate tube resonant cavities are arranged close to and back to each other. The inner legs of two pulling adjustable inner frames 4 of the same column tube resonant cavity are arranged at intervals to form a straight sound absorption narrow slit. The outer leg of each pulling adjustable frame 4 is provided with a fork opening for inserting the corresponding leg of the fixed frame 3, or the leg of the fixed frame 3 is provided with a fork opening for inserting the outer leg of the corresponding pulling adjustable frame 4, thereby forming the structure of the injector. The fixed outer frames 5 of the two sub-tube resonant cavities are integrally arranged and integrally in an H shape, the middle horizontal strip is provided with a linear sound absorption narrow slit, and two pulling adjustable outer frames 6 of the same sub-tube resonant cavity are arranged at intervals to just form the linear sound absorption narrow slit.
In addition, in order to improve the sound absorption effect, a distance is reserved between the inner side legs of the pulling adjustable inner frame 4 and the edge of the U-shaped bottom plate so as to increase the distance between the inner side legs of the two pulling adjustable inner frames 4, and the width of the linear sound absorption narrow slit formed at the position is larger than the width of the rest linear sound absorption narrow slits.
The tail end of the pull rod 7 is connected with the self-adaptive motor, the pull rod 7 is driven by the self-adaptive motor to move back and forth, and the self-adaptive motors on the two sides of the first and second column-dividing pipe resonant cavities 1 and 2 synchronously drive the corresponding pull rods 7 and pull the same distance.
The elastic modulus of the material adopted by the first microtube resonant cavity 1 and the second microtube resonant cavity 2 is 2.46GPa, and the density is 1.10g/cm3But is not limited thereto.
Referring to fig. 1 to 3, the non-single low-frequency ultra-open ventilation adjustable sound-absorbing unit a is fixedly installed in the open ventilation airflow channel B, and the cross section of the non-single low-frequency ultra-open ventilation adjustable sound-absorbing unit a is smaller than that of the airflow channel B, so that an airflow passing space C is formed between the inner wall of the airflow channel B and the outer wall of the non-single low-frequency ultra-open ventilation adjustable sound-absorbing unit a.
At least one row of non-single low-frequency ultra-open ventilation adjustable sound absorption units A close to the wall is arranged in the airflow channel B, each row of non-single low-frequency ultra-open ventilation adjustable sound absorption units A form a non-single low-frequency ultra-open ventilation adjustable sound absorption unit group, the pull rods 7 positioned on the same row are connected into a whole and driven by the same self-adaptive motor, and the whole forms a non-single low-frequency ultra-open ventilation adjustable sound absorber. The number of the non-single low-frequency ultra-open ventilation adjustable sound absorption units A is determined according to the cross-sectional dimension of the airflow channel B.
As shown in fig. 4-5, the non-single low-frequency ultra-open ventilation adjustable sound absorber is further equipped with an adaptive recognition system, and the adaptive recognition system includes a microphone module, a single chip microcomputer, and an adaptive motor. The microphone module is used for recognizing an environmental noise signal, then the signal is input into the single chip microcomputer, the single chip microcomputer converts an analog signal of a real world into a digital signal through the ADC chip, the digital signal is subjected to discrete Fourier transform through compiling a single chip microcomputer program and a computer, each harmonic is calculated, a main frequency is calculated, then an output signal of a pulling distance is determined according to the frequency, and then the self-adaptive motor is used for realizing self-adaptive sound absorption and noise reduction through pulling the sound absorption unit.
Claims (4)
1. A non-single low-frequency ultra-open ventilation adjustable sound absorption unit comprises a first branch tube resonant cavity (1) and a second branch tube resonant cavity (2) which are symmetrically arranged in front and back side by side, wherein each branch tube resonant cavity consists of an inner cavity and an outer cavity and is integrally in a shape like a Chinese character 'hui', and the upper side and the lower side of each of the first branch tube resonant cavity and the second branch tube resonant cavity (1 and 2) are respectively provided with a cover plate so as to enclose a sound absorption channel; the first branch is in lateral wall middle part, lateral wall middle part behind the exocoel before the exocoel of first branch tubulation resonant cavity (1), lateral wall middle part, behind the exocoel of lateral cavity before the exocoel of second branch tubulation resonant cavity (2) is provided with respectively in lateral wall middle part, lateral wall middle part behind the exocoel, the exocoel back side wall middle part with branch 'a' word sound absorption slot that is high such as tubulation resonant cavity, its characterized in that:
the inner cavity of each sub-column tube resonant cavity is defined by a fixed inner frame (3) and a left pulling adjustable inner frame (4) and a right pulling adjustable inner frame (4), the outer cavity of each sub-column tube resonant cavity is defined by a fixed outer frame (5) and a left pulling adjustable outer frame (6), the fixed inner frame (3) and the two pulling adjustable inner frames (4) are respectively connected through a similar injector structure, the pulling adjustable inner frames (4) are fixedly connected with the corresponding pulling adjustable outer frames (6) through pull rods (7), the pull rods (7) extend out of the adjustable outer frames (6), the pulling adjustable inner frames (4) and the adjustable outer frames (6) move synchronously in a front-back pulling mode through the pull rods (7), and the sizes of the inner cavity and the outer cavity can be adjusted simultaneously.
2. The non-unitary low frequency ultra-open ventilation adjustable sound absorbing unit of claim 1, wherein: the fixed inner frame (3) and the pulling adjustable inner frame (4) are respectively in a U shape, the fixed inner frames (3) of the two sub-tube resonant cavities are arranged close to and back to each other, the inner legs of the two pulling adjustable inner frames (4) of the same sub-tube resonant cavity are arranged at intervals to just form a linear sound absorption narrow slit, and the outer leg of each pulling adjustable frame (4) is provided with a fork port for inserting the corresponding leg of the fixed frame (3) or the leg of the fixed frame (3) is provided with a fork port for inserting the outer leg of the corresponding pulling adjustable frame (4), so that the injector-like structure is formed; the fixed outer frames (5) of the two sub-tube resonant cavities are integrally arranged and integrally in an H shape, the middle horizontal strip is provided with a linear sound absorption narrow slit, and two pulling adjustable outer frames (6) of the same sub-tube resonant cavity are arranged at intervals to just form the linear sound absorption narrow slit.
3. The non-unitary low frequency ultra-open ventilation adjustable sound absorbing unit of claim 2, wherein: the inner side legs of the pulling adjustable inner frames (4) are away from the edge of the U-shaped bottom plate by a certain distance so as to increase the distance between the inner side legs of the two pulling adjustable inner frames (4), and the width of the linear sound absorption narrow gap formed at the position is larger than that of the other linear sound absorption narrow gaps.
4. The non-unitary low frequency ultra-open ventilation adjustable sound absorbing unit of any one of claims 1-3, wherein: the tail end of the pull rod (7) is connected with the self-adaptive motor, the self-adaptive motor drives the pull rod (7) to move back and forth, and the self-adaptive motors on the two sides of the first and second array tube resonant cavities (1, 2) synchronously drive the corresponding pull rods (7) and pull the same distance.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202011512169.7A CN112728275A (en) | 2020-12-19 | 2020-12-19 | Non-single low-frequency ultra-open ventilation adjustable sound absorption unit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202011512169.7A CN112728275A (en) | 2020-12-19 | 2020-12-19 | Non-single low-frequency ultra-open ventilation adjustable sound absorption unit |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN112728275A true CN112728275A (en) | 2021-04-30 |
Family
ID=75603482
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202011512169.7A Pending CN112728275A (en) | 2020-12-19 | 2020-12-19 | Non-single low-frequency ultra-open ventilation adjustable sound absorption unit |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN112728275A (en) |
Citations (12)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2002065447A2 (en) * | 2001-02-09 | 2002-08-22 | Dow Global Technologies Inc. | Sound absorbing foam |
| US20040262077A1 (en) * | 2003-05-02 | 2004-12-30 | Huff Norman T. | Mufflers with enhanced acoustic performance at low and moderate frequencies |
| US20070034447A1 (en) * | 2005-08-10 | 2007-02-15 | William Proscia | Acoustic liner with bypass cooling |
| CN203549259U (en) * | 2013-09-30 | 2014-04-16 | 同济大学 | Frequency-adjustable micro-perforated pipe muffler with variable-volume expanding cavity |
| CN107002601A (en) * | 2014-10-31 | 2017-08-01 | 尤姆弗泰克有限公司 | Acoustic resonator |
| CN107990079A (en) * | 2017-11-24 | 2018-05-04 | 深圳市尚维高科有限公司 | The low frequency absorption device allowed fluid from |
| CN108399911A (en) * | 2017-02-06 | 2018-08-14 | 北京市劳动保护科学研究所 | A kind of ventilation and heat sound insulating structure of broad band low frequency |
| JP2019191343A (en) * | 2018-04-24 | 2019-10-31 | 清水建設株式会社 | Noise reduction structure |
| CN110822206A (en) * | 2019-11-18 | 2020-02-21 | 重庆大学 | Super-open type efficient ventilation and sound absorption unit and sound absorber |
| CN111030507A (en) * | 2019-12-30 | 2020-04-17 | 陕西师范大学 | Double-cavity coupling type noise generator and power generation method |
| EP3651150A1 (en) * | 2017-07-05 | 2020-05-13 | Fujifilm Corporation | Sound-damping system |
| CN111989740A (en) * | 2018-04-18 | 2020-11-24 | 富士胶片株式会社 | Sound insulation structure |
-
2020
- 2020-12-19 CN CN202011512169.7A patent/CN112728275A/en active Pending
Patent Citations (12)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2002065447A2 (en) * | 2001-02-09 | 2002-08-22 | Dow Global Technologies Inc. | Sound absorbing foam |
| US20040262077A1 (en) * | 2003-05-02 | 2004-12-30 | Huff Norman T. | Mufflers with enhanced acoustic performance at low and moderate frequencies |
| US20070034447A1 (en) * | 2005-08-10 | 2007-02-15 | William Proscia | Acoustic liner with bypass cooling |
| CN203549259U (en) * | 2013-09-30 | 2014-04-16 | 同济大学 | Frequency-adjustable micro-perforated pipe muffler with variable-volume expanding cavity |
| CN107002601A (en) * | 2014-10-31 | 2017-08-01 | 尤姆弗泰克有限公司 | Acoustic resonator |
| CN108399911A (en) * | 2017-02-06 | 2018-08-14 | 北京市劳动保护科学研究所 | A kind of ventilation and heat sound insulating structure of broad band low frequency |
| EP3651150A1 (en) * | 2017-07-05 | 2020-05-13 | Fujifilm Corporation | Sound-damping system |
| CN107990079A (en) * | 2017-11-24 | 2018-05-04 | 深圳市尚维高科有限公司 | The low frequency absorption device allowed fluid from |
| CN111989740A (en) * | 2018-04-18 | 2020-11-24 | 富士胶片株式会社 | Sound insulation structure |
| JP2019191343A (en) * | 2018-04-24 | 2019-10-31 | 清水建設株式会社 | Noise reduction structure |
| CN110822206A (en) * | 2019-11-18 | 2020-02-21 | 重庆大学 | Super-open type efficient ventilation and sound absorption unit and sound absorber |
| CN111030507A (en) * | 2019-12-30 | 2020-04-17 | 陕西师范大学 | Double-cavity coupling type noise generator and power generation method |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN1082780C (en) | Frequency selective acoustic waveguide damping | |
| US5361380A (en) | Woofer module for use in a television set | |
| CN112863469B (en) | Low-frequency ultra-open ventilation self-adaptive high-efficiency sound absorber | |
| CN110822206A (en) | Super-open type efficient ventilation and sound absorption unit and sound absorber | |
| CN112728275A (en) | Non-single low-frequency ultra-open ventilation adjustable sound absorption unit | |
| CN104747856A (en) | Wind pipe noise reducing structure, wind pipe and wind pipe type air conditioner | |
| CN215681835U (en) | Noise-reduction charger | |
| CN205160760U (en) | Audio amplifier based on many sound sources | |
| CN203206443U (en) | A sound system and a TV set | |
| CN105228051A (en) | There is the multiple unit thin type audio amplifier of S shape conduit | |
| CN112651155A (en) | Finite element simulation and demonstration verification method for ventilation self-adaptive low-frequency efficient sound absorber | |
| CN209693026U (en) | Intelligent sound speaker | |
| CN213925926U (en) | Multiple formula of making an uproar integration sound barrier that falls | |
| CN207124717U (en) | A kind of two-sided extrusion formula passive sound box | |
| CN210768310U (en) | Vertical pulling type laminated buffer of vertical hinged door | |
| CN2586317Y (en) | Television heavy wafer and television | |
| CN101707731A (en) | Array transmission line active vehicle-mounted sound system | |
| CN201004710Y (en) | Low sound enhanced sound box for TV | |
| CN201504307U (en) | Active vehicular sound-box system with array transmission line | |
| CN220139707U (en) | Adjustable sound structure | |
| CN206131397U (en) | Folded plate type silencer | |
| CN206784791U (en) | A kind of indoor decoration plate with sound insulation function | |
| CN219063743U (en) | Combined silencing static pressure box | |
| CN104141522A (en) | Rear-arranged main silencer | |
| CN203859855U (en) | Sound equipment and laying frame thereof |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| RJ01 | Rejection of invention patent application after publication |
Application publication date: 20210430 |
|
| RJ01 | Rejection of invention patent application after publication |