A parallel spring oscillator sound absorption structure

Abstract

The present invention discloses a parallel spring oscillator sound absorption structure, comprising: at least one sound absorption unit; the sound absorption unit comprises: a spring oscillator module and a reversing box; the spring oscillator module comprises: a spring, a oscillator and a damper; the reversing box comprises: a bottom plate and a wall plate bent inward at the top. The present invention adjusts the force resistance of the spring in each of the sound absorption units, the mass of the oscillator and the force resistance of the damper, so that the spring oscillator modules in each of the sound absorption units have different resonance frequencies, so that by connecting at least one spring oscillator module with different resonance frequencies in parallel, the sound absorption bandwidth of the entire sound absorption structure can be effectively widened; in addition, the present invention utilizes the oscillator to convert sound energy into mechanical energy and consumes the converted mechanical energy through damping, and at the same time, with the assistance of the offset effect of the anti-phase secondary sound source, the sound absorption efficiency can be improved.

Description

Technical Field

[0001] The invention relates to the technical field of sound absorption and noise reduction, and in particular to a parallel spring oscillator sound absorption structure. Background Art

[0002] Sound-absorbing materials are one of the important materials in acoustics, and are widely used in noise reduction in the fields of construction, vehicles and ships, aerospace, mechanical equipment, and the sound quality design of important halls. There are two main types of sound-absorbing materials and structures: one is porous resistive sound-absorbing materials, which are mainly used for medium and high frequency sound absorption above 250Hz, such as glass wool, wood wool board, polyester fiber, etc.; the other is resonant sound-absorbing structures, which are mainly used for low frequency sound absorption below 250Hz, such as perforated plates based on the Helmholtz resonance cavity principle, and resonant structures such as thin plates and films.

[0003] The defect of perforated plate is that due to the small sound mass, a larger sound capacity is required when absorbing low frequency, and a larger sound capacity will lead to a larger volume of the cavity, which in turn leads to a large thickness of the sound-absorbing structure, which occupies a large amount of effective space in the room, and the sound absorption frequency band is narrow. For example, to absorb 100Hz sound waves, the cavity behind the plate is generally larger than 200mm.

[0004] The defect of the thin plate resonant structure is that the plate belongs to a distributed vibration system, and its force resistance components are complex, mainly composed of the air spring stiffness in the cavity behind the plate, the constraint stiffness at the connection between the plate and the frame, and the stiffness of the plate itself. Therefore, its frequency response characteristics are complex and it is not easy to design according to the noise spectrum.

[0005] The defects of thin film resonance structures are: on the one hand, the frequency response characteristics are complex and difficult to design; on the other hand, due to the soft surface of the membrane, it is not applicable in many cases, and most membranes have a low fire resistance level. Summary of the invention

[0006] The object of the present invention is to provide a parallel spring oscillator sound absorption structure to absorb low-frequency noise, increase the sound absorption bandwidth and improve the sound absorption efficiency.

[0007] To achieve the above object, the present invention provides the following solutions:

[0008] A parallel spring vibrator sound absorbing structure, the parallel spring vibrator sound absorbing structure comprising: at least one sound absorbing unit; when the number of the sound absorbing units is multiple, the sound absorbing units are arranged in an array;

[0009] The sound absorbing unit comprises: a spring oscillator module and a phase reversal box;

[0010] The spring oscillator module comprises: a spring, an oscillator and a damper; the spring resistance, the mass of the oscillator and the damper resistance in each of the sound absorbing units are different, so that the spring oscillator module in each of the sound absorbing units has a different resonance frequency;

[0011] The phase inversion box comprises: a bottom plate and a wall plate bent inward at the top; the bottom plate and the wall plate together enclose a box body with an opening at the top;

[0012] The spring, the vibrator and the damper are all located inside the box; the two contact surfaces of the spring are in contact with the bottom plate and one surface of the vibrator respectively; the other surface of the vibrator is in contact with the damper; the damper is located between the vibrator and the inwardly bent portion of the wall plate; the bottom plate, the wall plate, the vibrator and the damper together enclose a closed cavity;

[0013] When a sound wave comes, the vibrator in the spring vibrator module with a corresponding resonant frequency vibrates under the excitation of the sound wave, converts the sound energy into mechanical energy, and then consumes the mechanical energy through corresponding damping; at the same time, the air column in the cavity vibrates under the action of the vibrator, forming a secondary sound source.

[0014] Optionally, the sound absorbing unit further includes:

[0015] The inverted tube; the other side of the vibrator is a sound receiving surface, and the sound receiving surface of the vibrator is provided with a radiation hole; the inverted tube is located inside the inverted box, and is respectively connected to the inverted box and the radiation hole; the inverted tube is used to guide the airflow vibrating in the cavity to the radiation hole in a manner opposite to the incident sound wave, so that the radiation hole radiates sound waves outward, which are superimposed and offset with the incident sound wave in an opposite phase.

[0016] Optionally, the parallel spring oscillator sound absorption structure further includes:

[0017] The back panel is connected to the keel through a slot to be fixed on the wall or ceiling; the sound absorbing unit is installed on the back panel.

[0018] Optionally, the resonant frequency of the i-th spring oscillator module is:

[0019]

[0020] Where i is a positive integer greater than or equal to 1; f i is the resonant frequency of the i-th spring oscillator module; K i is the force resistance of the spring in the i-th spring oscillator module; M i is the mass of the oscillator in the i-th spring oscillator module.

[0021] Optionally, the velocity resonance peak bandwidth of the i-th spring oscillator module is:

[0022]

[0023] Where i is a positive integer greater than or equal to 1; f i is the resonant frequency of the i-th spring oscillator module; Δf i is the velocity resonance peak bandwidth of the i-th spring oscillator module; M i is the mass of the oscillator in the i-th spring oscillator module; R i is the force resistance of the damping in the i-th spring oscillator module.

[0024] Optionally, the overall size of each of the sound absorbing units is smaller than 1 / 4 of the wavelength corresponding to the highest sound wave frequency absorbed.

[0025] Optionally, the inverted tube is mounted on the bottom plate of the inverted box and the wall plate located on the side; the length of the inverted tube is equal to 1 / 2 of the wavelength of the sound wave corresponding to the resonance frequency of the corresponding spring oscillator module.

[0026] Optionally, the resonance frequency of each of the spring oscillator modules is a one-third octave band center frequency within a frequency range of 16 Hz-500 Hz.

[0027] Optionally, the number of the sound absorbing units is 9.

[0028] Optionally, the spring oscillator module, the inverter box and the inverter tube are all made of metal materials.

[0029] According to the specific embodiments provided by the present invention, the present invention discloses the following technical effects:

[0030] The present invention provides a parallel spring vibrator sound absorption structure, comprising: at least one sound absorption unit; the sound absorption unit comprises: a spring vibrator module and a phase reversal box; the spring vibrator module comprises: a spring, a vibrator and a damper; the phase reversal box comprises: a bottom plate and a wall plate with a top bent inward; the bottom plate and the wall plate together enclose a box body with a top opening; the spring, the vibrator and the damper are all located inside the box body; two contact surfaces of the spring are in contact with one side of the bottom plate and the vibrator respectively; the other side of the vibrator is in contact with the damper; the damper is located between the vibrator and the inward bent part of the wall plate; the bottom plate, the wall plate, the vibrator and the damper together enclose a closed cavity.

[0031] The present invention enables the spring vibrator modules in each sound absorbing unit to have different resonance frequencies by adjusting the force resistance of the spring in each sound absorbing unit, the mass of the vibrator and the force resistance of the damping; when a sound wave is transmitted, the vibrator in the spring vibrator module with the corresponding resonance frequency vibrates under the excitation of the sound wave, converts the sound energy into mechanical energy, and then consumes the mechanical energy through the corresponding damping; at the same time, the air column in the cavity vibrates under the action of the vibrator to form a secondary sound source.

[0032] The present invention can effectively broaden the sound absorption bandwidth of the entire sound absorption structure by connecting at least one spring oscillator module with different resonance frequencies in parallel; the oscillator is used to convert sound energy into mechanical energy and the converted mechanical energy is consumed through damping, while the counteracting effect of the inverted secondary sound source is used to improve the sound absorption efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0034] Figure 1 It is a structural schematic diagram of the parallel spring oscillator sound absorption structure of the present invention;

[0035] Figure 2 It is a schematic diagram of the connection of velocity resonance peak curves of the spring vibrator modules of the parallel spring vibrator sound absorption structure of the present invention.

[0036] Explanation of symbols: spring—1, vibrator—2, damper—3, bass reflex box—4, bass reflex tube—5, radiation hole—6, back panel—7, sound absorbing unit—8. DETAILED DESCRIPTION

[0037] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0038] The object of the present invention is to provide a parallel spring oscillator sound absorption structure to absorb low-frequency noise, increase the sound absorption bandwidth and improve the sound absorption efficiency.

[0039] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0040] Figure 1 It is a structural schematic diagram of the parallel spring oscillator sound absorption structure of the present invention, wherein: Figure 1 Figure (a) is a schematic diagram of the planar structure of the parallel spring oscillator sound absorption structure of the present invention, Figure 1 FIG. (b) is a schematic cross-sectional view of the parallel spring oscillator sound absorption structure of the present invention. Figure 1 As shown, the parallel spring oscillator sound absorption structure provided by the present invention includes: at least one sound absorption unit 8; when the number of the sound absorption units 8 is multiple, the sound absorption units 8 are arranged in an array, and the spring oscillator modules in each sound absorption unit 8 are connected in parallel with each other.

[0041] Specifically, the sound absorbing unit 8 includes: a spring oscillator module and a phase reversal box 4; the spring oscillator module includes: a spring 1, a oscillator 2 and a damper 3; the spring 1 in each of the sound absorbing units 8 has a different force resistance, the mass of the oscillator 2 and the force resistance of the damper 3, so that the spring oscillator modules in each of the sound absorbing units 8 have different resonance frequencies. The phase reversal box 4 includes: a bottom plate and a wall plate with a top bent inward; the bottom plate and the wall plate together enclose a box body with an open top.

[0042] The spring 1, the vibrator 2 and the damper 3 are all located inside the box; the two contact surfaces of the spring 1 are in contact with the bottom plate and one side of the vibrator 2 respectively; the other side of the vibrator 2 is in contact with the damper 3; the damper 3 is located between the vibrator 2 and the inwardly bent part of the wall panel; the bottom plate, the wall panel, the vibrator 2 and the damper 3 together enclose a closed cavity.

[0043] When a sound wave is transmitted, the vibrator 2 in the spring vibrator module having a corresponding resonant frequency vibrates under the excitation of the sound wave, converts the sound energy into mechanical energy, and then consumes the mechanical energy through the corresponding damping 3; at the same time, when the vibrator 2 vibrates, the corresponding spring 1 vibrates under the drive of the vibrator 2, so that the volume of the cavity changes, that is, the air column in the cavity vibrates under the action of the vibrator 2, forming a secondary sound source for active noise control.

[0044] Furthermore, the sound absorbing unit 8 further includes: an inverted tube 5; the other side of the vibrator 2 is a sound receiving surface, and the sound receiving surface of the vibrator 2 is provided with a radiation hole 6; the inverted tube 5 is located inside the inverted box 4, and is respectively connected to the inverted box 4 and the radiation hole 6. The inverted tube 5 cooperates with the inverted box 4. When the air column in the cavity of the inverted box 4 vibrates to form a secondary sound source, the inverted tube 5 guides the vibrating airflow in the cavity to the radiation hole 6 in a manner opposite to the incident sound wave, so that the radiation hole 6 radiates sound waves outward, so that the secondary sound source radiated outward is superimposed and offset with the incident sound wave in an opposite phase, so that the sound absorption capacity of the sound absorbing structure is further enhanced.

[0045] In this embodiment, the spring oscillator modules have different resonant frequencies by adjusting the force resistance of the spring 1, the mass of the vibrator 2 and the force resistance of the damping 3 in each of the sound absorbing units 8. The spring oscillator modules are connected in parallel with each other, and the resonant frequency of each of the spring oscillator modules is adjusted so that the resonant frequency of the entire sound absorbing structure can cover the frequency range of wide-spectrum low-frequency noise, so that resonance can be generated under the action of sound waves of different frequencies within this range, and the vibrator 2 in each spring oscillator module is used to convert narrow-band sound energy with the same center frequency into mechanical energy near its resonant frequency, and the mechanical energy is consumed by the corresponding damping 3 to achieve passive noise control and effectively broaden the sound absorption bandwidth of the entire sound absorbing structure. The air column in the inverted box 4 vibrates under the action of the vibrator 2 and becomes a secondary sound source. The inverted tube 5 in the inverted box 4 guides the vibrating airflow in the inverted box 4 to the radiation hole 6 on the sound receiving surface of the vibrator 2 in an anti-phase manner to radiate sound waves, so that the radiated sound waves and the incident sound waves are superimposed and canceled in anti-phase to achieve active noise control and further enhance the sound absorption performance of the sound absorption structure.

[0046] As a specific implementation, the inverted tube 5 is installed on the bottom plate of the inverted box 4 and the wall plate on the side; the length of the inverted tube 5 is equal to 1 / 2 of the wavelength of the sound wave corresponding to the resonance frequency of the corresponding spring oscillator module. The overall size of each of the sound absorbing units 8 is less than 1 / 4 of the wavelength corresponding to the highest sound wave frequency absorbed.

[0047] Furthermore, the parallel spring oscillator sound absorption structure further includes: a back plate 7; the back plate 7 is connected to the keel through a slot to be fixed on the wall or ceiling; the sound absorption unit 8 is installed on the back plate.

[0048] Preferably, the spring oscillator module, the inverted box 4, the inverted tube 5 and the back plate 7 are all made of metal materials, so that the entire sound absorbing structure has good fireproof performance.

[0049] Furthermore, the present invention also provides a method for calculating the resonant frequency and velocity resonance peak bandwidth of each of the spring oscillator modules, which is specifically as follows:

[0050] The resonant frequency of the i-th spring oscillator module is:

[0051]

[0052] Where i is a positive integer greater than or equal to 1; f i is the resonant frequency of the i-th spring oscillator module; K i is the force resistance of the spring in the i-th spring oscillator module; M i is the mass of the oscillator in the i-th spring oscillator module.

[0053] The velocity resonance peak bandwidth of the i-th spring oscillator module is:

[0054]

[0055] Where i is a positive integer greater than or equal to 1; Δf i is the velocity resonance peak bandwidth of the i-th spring oscillator module; M i is the mass of the oscillator in the i-th spring oscillator module; R i is the force resistance of the damping in the i-th spring oscillator module.

[0056] As a specific implementation, the resonant frequency of each of the spring oscillator modules is a one-third octave band center frequency within the frequency range of 16 Hz-500 Hz. That is, the resonant frequency points of each of the spring oscillator modules are any one of 16 Hz, 20 Hz, 25 Hz, 31.5 Hz, 40 Hz, 50 Hz, 63 Hz, 80 Hz, 100 Hz, 125 Hz, 160 Hz, 200 Hz, 250 Hz, 315 Hz, 400 Hz and 500 Hz, so that the parallel spring oscillator sound absorption structure provided by the present invention can selectively absorb broadband low-frequency noise within the range of 16 Hz-500 Hz.

[0057] Furthermore, the present invention also adjusts the force resistance of the spring 1, the mass of the vibrator 2 and the force resistance of the damping 3 in each of the sound absorbing units 8 so that the velocity resonance peak curves of the 8 spring vibrator modules in each of the sound absorbing units are connected at the position of the half-power point, thereby being able to continuously absorb sound waves in any frequency range of 16 Hz-500 Hz.

[0058] In this embodiment, the number of sound absorbing units 8 of the parallel spring oscillator sound absorbing structure of the present invention is 9, that is, the parallel spring oscillator sound absorbing structure of the present invention includes: 9 parallel spring oscillator modules, 9 inverted boxes 4, 9 inverted tubes 5 and a back plate 7.

[0059] The resonance frequencies of the 9 spring oscillator modules are 31.5Hz, 40Hz, 50Hz, 63Hz, 80Hz, 100Hz, 125Hz, 160Hz and 200Hz respectively. By further controlling the force resistance K, mass M and force resistance R, the speed resonance peak bandwidth of each spring oscillator module is adjusted, and the speed resonance peaks of the 9 parallel spring oscillator modules are connected at the half-power point, so as to cover the low-frequency noise with a bandwidth of 31.5Hz-200Hz. For details on the connection of the vibration speed resonance peak curves of the 9 spring oscillator modules, see Figure 2 , where 1 When the normalized velocity amplitude is 0.707, the point on the velocity resonance peak curve of each spring oscillator module is the half-power point.

[0060] The total thickness of the entire sound absorption structure is about 60 mm, and the length and width are both 400 mm. The normal incidence sound absorption coefficients of each frequency band are shown in Table 1. It can be seen from Table 1 that the parallel spring oscillator sound absorption structure of the present invention has good sound absorption characteristics for low-frequency noise.

[0061] Table 1 Normal incidence sound absorption coefficient corresponding to the center frequency of each frequency band

[0062] Band center frequency (Hz) 31.5 40 50 63 80 100 125 160 200 Normal incidence sound absorption coefficient 0.62 0.73 0.81 0.82 0.83 0.82 0.84 0.83 0.86

[0063] The present invention utilizes parallel spring oscillator modules to absorb low-frequency broadband sound waves, and utilizes the inverted box and the inverted tube to radiate outwardly a secondary sound source that is in antiphase with the incident sound wave, partially offsetting the incident sound wave, and further improving the sound absorption efficiency of the system. The reason for using the spring oscillator is to utilize the elastic resistance and mass resistance of the spring oscillator to replace the elastic resistance and mass resistance of the Helmholtz resonance cavity, thereby being able to reduce the volume and thickness of the structure, so that the low-frequency sound absorption structure has a smaller volume. By connecting the sound absorption units with different resonance frequencies in parallel, a low-frequency sound absorption structure with a wider frequency band can be made. Since all the components in the structure are made of metal materials, its fireproof performance can meet the highest standards in actual engineering. By further combining the low-frequency broadband sound absorption structure provided by the present invention with the resistive medium and high frequency sound absorption material, a full-band sound absorption structure of 20Hz-8000Hz can be made, which can be widely used in noise reduction engineering.

[0064] In summary, compared with the existing low-frequency resonance sound absorption structure, the parallel spring oscillator sound absorption structure provided by the present invention has the following advantages:

[0065] 1. Connecting multiple spring oscillator modules with different resonance frequencies in parallel can effectively broaden the sound absorption bandwidth of the entire sound absorption structure.

[0066] 2. The passive noise control is combined with the active noise control. On the one hand, the damping components are used to consume the mechanical energy converted from the sound energy. On the other hand, the counteracting effect of the reversed secondary sound source is used to achieve high sound absorption efficiency.

[0067] 3. All components can be made of metal and have good fire resistance.

[0068] 4. The frequency response characteristics of the spring oscillator module are simple, and the amplitude-frequency characteristics of the entire sound-absorbing structure can be designed and optimized according to the noise spectrum.

[0069] In this specification, each embodiment is described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the embodiments can be referred to each other. For the system disclosed in the embodiment, since it corresponds to the method disclosed in the embodiment, the description is relatively simple, and the relevant parts can be referred to the method part.

[0070] This article uses specific examples to illustrate the principles and implementation methods of the present invention. The above examples are only used to help understand the core idea of ​​the present invention. At the same time, for those skilled in the art, according to the idea of ​​the present invention, there will be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be understood as limiting the present invention.

Claims

1. A parallel spring oscillator sound absorption structure, characterized in that: The parallel spring oscillator sound absorbing structure comprises: at least one sound absorbing unit; when there are multiple sound absorbing units, each of the sound absorbing units is arranged in an array; The sound absorbing unit comprises: a spring oscillator module and a phase reversal box; The spring oscillator module comprises: a spring, an oscillator and a damper; the spring resistance, the mass of the oscillator and the damper resistance in each of the sound absorbing units are different, so that the spring oscillator module in each of the sound absorbing units has a different resonance frequency; The phase inversion box comprises: a bottom plate and a wall plate bent inward at the top; the bottom plate and the wall plate together enclose a box body with an open top; The spring, the vibrator and the damper are all located inside the box; the two contact surfaces of the spring are in contact with the bottom plate and one surface of the vibrator respectively; the other surface of the vibrator is in contact with the damper; the damper is located between the vibrator and the inwardly bent portion of the wall plate; the bottom plate, the wall plate, the vibrator and the damper together enclose a closed cavity; When a sound wave comes, the vibrator in the spring vibrator module with a corresponding resonant frequency vibrates under the excitation of the sound wave, converts the sound energy into mechanical energy, and then consumes the mechanical energy through corresponding damping; at the same time, the air column in the cavity vibrates under the action of the vibrator, forming a secondary sound source.

2. The parallel spring oscillator sound absorbing structure according to claim 1, characterized in that: The sound absorbing unit further comprises: The inverted tube; the other side of the vibrator is a sound receiving surface, and the sound receiving surface of the vibrator is provided with a radiation hole; the inverted tube is located inside the inverted box, and is respectively connected to the inverted box and the radiation hole; the inverted tube is used to guide the airflow vibrating in the cavity to the radiation hole in a manner opposite to the incident sound wave, so that the radiation hole radiates sound waves outward, which are superimposed and offset with the incident sound wave in an opposite phase.

3. The parallel spring oscillator sound absorbing structure according to claim 1, characterized in that: The parallel spring oscillator sound absorption structure also includes: The back panel is connected to the keel through a slot to be fixed on the wall or ceiling; the sound absorbing unit is installed on the back panel.

4. The parallel spring oscillator sound absorbing structure according to claim 1, characterized in that: The resonant frequency of the i-th spring oscillator module is: Wherein, i is a positive integer greater than or equal to 1; f i is the resonant frequency of the i-th spring oscillator module; K i is the force resistance of the spring in the i-th spring oscillator module; M i is the mass of the oscillator in the i-th spring oscillator module.

5. The parallel spring oscillator sound absorbing structure according to claim 1, characterized in that: The velocity resonance peak bandwidth of the i-th spring oscillator module is: Wherein, i is a positive integer greater than or equal to 1; f i is the resonant frequency of the i-th spring oscillator module; Δf i is the velocity resonance peak bandwidth of the i-th spring oscillator module; M i is the mass of the oscillator in the i-th spring oscillator module; R i is the force resistance of the damping in the i-th spring oscillator module.

6. The parallel spring oscillator sound absorbing structure according to claim 1, characterized in that: The overall size of each of the sound absorbing units is smaller than 1 / 4 of the wavelength corresponding to the highest sound wave frequency absorbed.

7. The parallel spring oscillator sound absorbing structure according to claim 2, characterized in that: The inverted tube is installed on the bottom plate of the inverted box and the wall plate located on the side; the length of the inverted tube is equal to 1 / 2 of the wavelength of the sound wave corresponding to the resonance frequency of the corresponding spring oscillator module.

8. The parallel spring oscillator sound absorbing structure according to claim 1, characterized in that: The resonant frequency of each of the spring oscillator modules is a one-third octave band center frequency within a frequency range of 16 Hz-500 Hz.

9. The parallel spring oscillator sound absorbing structure according to claim 1, characterized in that: The number of the sound absorbing units is 9.

10. The parallel spring oscillator sound absorbing structure according to claim 2, characterized in that: The spring oscillator module, the inverter box and the inverter tube are all made of metal materials.

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