WO2018176665A1

WO2018176665A1 - Composite ceramic sound-absorbing member and sound production device module

Info

Publication number: WO2018176665A1
Application number: PCT/CN2017/090644
Authority: WO
Inventors: 潘泉泉; 曹晓东; 刘金利
Original assignee: 歌尔股份有限公司
Priority date: 2017-03-30
Filing date: 2017-06-28
Publication date: 2018-10-04
Also published as: CN107046665B; CN107046665A

Abstract

Disclosed is a composite ceramic sound=absorbing member (1) and a sound production device module. The composite ceramic sound-absorbing member (1) comprises a composite ceramic sound-absorbing material (10) ,wherein the composite ceramic sound-absorbing material (10) comprises microporous activated carbon and aluminium oxide, the microporous activated carbon has micropores, the pore size of the micropores ranges from 0.2 to 0.8 nm, the aluminium oxide has mesopores, the pore size of the mesopores ranges from 2 to 40 nm, the composite ceramic sound-absorbing member (1) has macropores (11),and the pore size of the macropores (11) is greater than 0.1 microns. The composite ceramic sound-absorbing member (1) has a better acoustic performance improvement effect compared with traditional foam sound-absorbing materials.

Description

Composite ceramic sound absorbing member and sounding device module

Technical field

The invention belongs to the technical field of sounding devices, and in particular, the invention relates to a composite ceramic sound absorbing member and a sounding device module.

Background technique

As a kind of energy converter that converts electrical signals into sound signals, the sounding device module is an indispensable component in electroacoustic products, and is often used in consumer electronic products such as mobile phones and computers. The sounding device module is usually composed of a casing and a sounding device unit, and the sounding device unit separates the inner cavity of the entire module casing into two chambers of a front sound chamber and a rear sound chamber.

In order to improve the acoustic performance of the sounding device module, in the prior art, a means for adding a sound absorbing member in the rear sound cavity is generally adopted to absorb the sound energy, which is equivalent to expanding the volume of the rear cavity, thereby achieving the effect of reducing the module F0. Conventional sound absorbing members are foamed foams such as polyurethane, melamine and the like.

In recent years, with the increasing thinness of wearable electronic products, the volume of the sounding device module has been correspondingly reduced, and the volume of the sound chamber is continuously compressed, so that the volume of the conventional foam-like sound absorbing member filled therein is also Correspondingly, it becomes smaller and smaller, and it is difficult to reduce the resonance frequency F0 of the sounding device module to be sufficiently low, and the medium and low frequency sound quality of the sounding device module cannot be guaranteed.

Therefore, it is necessary to provide a new type of sound absorbing member that is better in effect, instead of the conventional foaming type foam. In the case of miniaturization of electronic products, the sounding device module can achieve acoustic performance requirements.

Summary of the invention

It is an object of the present invention to provide an improved technical solution for a sound absorbing member.

According to a first aspect of the present invention, a composite ceramic sound absorbing member is provided, the composite ceramic sound absorbing member comprising a composite ceramic sound absorbing material, the composite ceramic sound absorbing material comprising microporous activated carbon And alumina having micropores in the microporous activated carbon, the micropores having a pore size ranging from 0.2 to 0.8 nm, the alumina having mesopores, and the mesopores having a pore size ranging from 2 to 40 nm. The composite ceramic sound absorbing member has a large hole having a pore diameter larger than 0.1 μm.

Optionally, the mass fraction of the microporous activated carbon in the composite ceramic sound absorbing material ranges from 15% to 75%, and the mass fraction of the alumina in the composite ceramic sound absorbing material ranges from 20% to 80%.

Optionally, a modifier is added to the composite ceramic sound absorbing material, and the modifier has a mass fraction ranging from 0.1% to 10% in the composite ceramic sound absorbing material, and the modifier includes chromium oxide, calcium oxide, and molybdenum oxide. At least one of them.

Optionally, the composite ceramic sound absorbing member comprises a macroporous member configured to be attached to the large aperture member, the large aperture member having the large aperture.

Optionally, the macroporous member is a carbon fiber skeleton configured to be removed in whole or in part during the preparation of the composite ceramic sound absorbing member.

Optionally, the macroporous member is a foam having a cell structure, and the composite ceramic sound absorbing material is attached to the surface of the foam and the pore structure.

Optionally, the composite ceramic sound absorbing member is formed by curing a sound absorbing slurry made of a composite ceramic sound absorbing material, and a sounding agent is added to the sound absorbing slurry, and the foaming agent is configured to be in the sound absorbing slurry. Bubbles are generated, and after the sound absorbing paste is solidified, the pores formed at the bubbles constitute the large pores.

Optionally, the ceramic sound absorbing member is formed by curing a sound absorbing slurry made of a composite ceramic sound absorbing material, and a gelling agent is added to the sound absorbing slurry, and the gel agent is configured to increase the sound absorbing slurry. The viscosity of the sound absorbing slurry is configured to be solidified by mechanical agitation, and the bubbles in the sound absorbing slurry are mechanically agitated to form the large pores.

Optionally, the micropores have a local peak diameter of 0.3-0.7 nm, the mesopores have a local peak of 2-40 nm, and the macropore has a local peak of 0.1-25 micron.

Optionally, the composite ceramic sound absorbing member has a specific surface area distribution ranging from 200 to 900 m ² /g.

Optionally, the composite ceramic sound absorbing member is configured to be disposed in an area of the sound emitting device module capable of receiving sound.

The invention also provides a sounding device module, comprising a module shell and a sounding device unit And the composite ceramic sound absorbing member described above, wherein the sounding device unit and the composite ceramic sound absorbing member are disposed in the module housing.

One technical effect of the present invention is that the composite ceramic sound absorbing member provided by the present invention has a better acoustic performance improving effect than the conventional foam as the sound absorbing member.

Other features and advantages of the present invention will become apparent from the Detailed Description of the <RTIgt;

DRAWINGS

The accompanying drawings, which are incorporated in FIG

1 is a schematic structural view of a composite ceramic sound absorbing member provided by an embodiment of the present invention;

2 is a schematic structural view of a composite ceramic sound absorbing member provided by another embodiment of the present invention;

3 is a schematic view of a composite ceramic sound absorbing member placed in a sound emitting device module according to an embodiment of the present invention.

detailed description

Various exemplary embodiments of the present invention will now be described in detail with reference to the drawings. It should be noted that the relative arrangement of the components and steps, numerical expressions and numerical values set forth in the embodiments are not intended to limit the scope of the invention unless otherwise specified.

The following description of the at least one exemplary embodiment is merely illustrative and is in no way

Techniques, methods and apparatus known to those of ordinary skill in the relevant art may not be discussed in detail, but the techniques, methods and apparatus should be considered as part of the specification, where appropriate.

In all of the examples shown and discussed herein, any specific values are to be construed as illustrative only and not as a limitation. Therefore, other examples of the exemplary embodiments may have different Value.

It should be noted that similar reference numerals and letters indicate similar items in the following figures, and therefore, once an item is defined in one figure, it is not required to be further discussed in the subsequent figures.

The invention provides a composite ceramic sound absorbing member, and the sound absorbing member mainly plays a composite ceramic sound absorbing material. The composite ceramic sound absorbing material comprises microporous activated carbon and alumina. The microporous activated carbon has micropores having a pore size ranging from 0.2 to 0.8 nm. The micropores mainly play the role of adsorbing and desorbing air molecules, and are structures that directly absorb sound and absorb sound pressure in the composite ceramic sound absorbing member. The alumina has mesopores, and the mesopores have a pore size ranging from 2 to 40 nm. The mesopores can also function to adsorb and desorb air molecules, and the mesopores can also allow air molecules to quickly enter or escape from the micropores, thereby accelerating the ingress and egress of air. Since the frequency of sound pressure changes in the rear acoustic cavity of the sounding device is fast, it is necessary to enable air molecules to quickly enter and exit the micropores to achieve the performance requirements for absorbing sound pressure.

The method for forming a composite ceramic sound absorbing member for a composite ceramic sound absorbing material is not specifically limited in the present invention, and an optional embodiment will be exemplified in the subsequent content of the present invention. In particular, the composite ceramic sound absorbing member further has a large hole having a pore diameter larger than 0.1 μm. The function of the macropores is to increase the speed of air in and out of the composite ceramic sound absorbing member, so that air molecules can quickly enter the mesopores and micropores inside the composite ceramic sound absorbing member from the rear acoustic cavity, and conversely, the air molecules are also fast. Come out. The macropores may be formed in various forms in the present invention, and the present invention is not limited thereto.

Optionally, the mass fraction of the microporous activated carbon in the composite ceramic sound absorbing material ranges from 15% to 75%, and the mass fraction of the alumina in the composite ceramic sound absorbing material ranges from 20% to 80%. between. Within the above content range, the ratio of micropores and mesopores in the composite ceramic sound absorbing material can be effectively controlled, and the attraction performance of the composite ceramic sound absorbing material can be ensured. For example, the microporous activated carbon has a mass fraction of 60% and the alumina has a mass fraction of 35%. The remaining 5% of the mass fraction is occupied by other materials.

Further preferably, a modifier may be added to the composite ceramic sound absorbing material, The modifier is configured to increase the strength and rigidity of the composite ceramic sound absorbing member, and to reduce damage, peeling, and the like of the sound absorbing member during actual use. In an embodiment of the invention, the modifier has a mass fraction in the composite ceramic sound absorbing material ranging from 0.1% to 10%. The content of the modifier in the composite ceramic sound absorbing material should not be too high, otherwise the amount of micropores and mesopores will decrease, which will affect the sound absorbing effect of the composite ceramic sound absorbing member. Optionally, the modifier includes at least one of chromium oxide, calcium oxide, and molybdenum oxide, which is not limited in the present invention.

Optionally, the composite ceramic sound absorbing member further comprises a large hole member having a hole structure therein, and the hole structure constitutes the large hole. The composite ceramic sound absorbing material is configured to be attached to the surface of the macroporous member and the pore structure. In such an embodiment, the composite ceramic sound absorbing material may be configured as a powder or slurry to enable the composite ceramic sound absorbing material to adhere to the macroporous member.

Further, in a specific embodiment of the invention, the macroporous member may be a carbon fiber skeleton. The carbon fiber skeleton has a rich pore structure and is suitable as a large hole of a composite ceramic sound absorbing member. The powder or slurry of the composite ceramic sound absorbing material may be attached to the carbon fiber skeleton. In particular, in a subsequent processing process, such as a sintering and baking process, the composite ceramic sound absorbing material is consolidated and hardened, and is bonded to form a monolithic structure on the carbon fiber skeleton. The carbon fiber skeleton is completely or partially ablated and removed in the baking process, leaving only the structural member having a large pore formed by the composite ceramic sound absorbing material itself. The present invention does not specifically limit this, and those skilled in the art can select whether to completely or partially leave the carbon fiber skeleton in the finally produced composite ceramic sound absorbing member according to the performance requirements of the actual product.

In another embodiment of the present invention, as shown in FIG. 1, the macroporous member may be a foam 20 which is formed by foaming of a foamed material and has a good porous structure. The pore structure of the foam 20 can serve as the large pore. The composite ceramic sound absorbing material 10 is attached to the surface of the foam 20 and the pore structure. In this embodiment, an optional molding method is: arranging the composite ceramic sound absorbing material 10 into a sound absorbing slurry, and then immersing the foam 20 in a sound absorbing slurry to immerse the composite ceramic sound absorbing material 10 in a bubble. The cotton 20 is attached to the cell structure of the foam 20. Thereafter, drying and drying are further performed to solidify the composite ceramic sound absorbing material 10 on the foam 20 to form the composite ceramic sound absorbing member 1.

In particular, the above drying and drying treatment may be replaced by a calcination treatment to ablate and remove the foam. Since the composite ceramic sound absorbing material is sufficiently immersed in the foam, it is sintered and formed into a structural member having a large hole in the baking treatment. Whether the ablation is used to remove the foam can be selected according to the performance requirements of the actual product, and the present invention does not limit this.

Optionally, in another embodiment, the composite ceramic sound absorbing member does not adopt a macroporous member, but forms the large hole by self-curing bonding. The composite ceramic sound absorbing material is mixed with a solvent, an auxiliary agent and the like to be configured as a sound absorbing slurry. In particular, a blowing agent is added to the sound absorbing slurry. The blowing agent is configured to generate bubbles in the sound absorbing slurry, and the foaming agent may be selected from ammonium hydrogencarbonate, ammonium carbonate, etc., and the foaming agent decomposes to generate gas upon heating, thereby A large amount of bubbles are generated in the sound absorbing slurry. The size of the bubble can be controlled by adjusting the viscosity of the sound absorbing paste, the composition of the blowing agent, the temperature and speed of heating. The generated bubbles are made to conform to the requirements of the large hole 11. As shown in Fig. 2, the sound absorbing slurry can be filled into a specific mold for sizing and solidification processing, and the bubbles formed as described above form pores in the consolidated sound absorbing slurry, and the holes serve as the large holes 11. The structural member formed by the consolidation of the sound absorbing slurry is directly used as the composite ceramic sound absorbing member 1 and can be disposed in the acoustic cavity of the sounding device module. The shape can be matched with the structure of the sound chamber of the sounding device module, making full use of the space of the sound chamber.

In another embodiment, the macroporous member is also not used, but the composite ceramic sound absorbing material is configured as a sound absorbing paste. A gelling agent is added to the sound absorbing slurry. The gelling agent is configured to increase the viscosity of the sound absorbing slurry, and the sound absorbing slurry can be brought into a state of being complexed. Thereafter, the sound absorbing slurry may be stirred to blow air into the sound absorbing slurry to form bubbles in the sound absorbing slurry. Since the viscosity of the sound absorbing paste is high, the bubbles are sealed in the sound absorbing slurry. By controlling the stirring process, the size of the bubbles and the distribution of the bubbles can be made to meet the requirements of the large holes. Then, similarly to the above embodiment, as in the case of FIG. 2, the sound absorbing slurry can be filled into a specific mold for shaping and solidification processing, and the bubbles formed above form holes in the consolidated sound absorbing slurry. These holes serve as the large holes 11. The structural member formed by the consolidation of the sound absorbing slurry is directly used as the composite ceramic sound absorbing member 1 and can be disposed in the acoustic cavity of the sounding device module. The structural member formed by the sound absorbing slurry can be matched with the structure of the acoustic cavity of the sounding device module to make full use of the space of the acoustic cavity.

Fig. 3 shows the structure in which the composite ceramic sound absorbing member 1 is fixed in the acoustic cavity of the sounding device module. The sounding device module may have a module housing 30 having a rear acoustic cavity 31 and a single cell 32 therein, and the sounding device unit 33 is disposed in the single cell region 32. The composite ceramic sound absorbing member 1 is placed in the rear sound chamber 31, and the sound generated when the sounding device unit 33 is operated is transmitted to the rear sound chamber 31 in addition to being transmitted from the sound outlet port, and the composite ceramic sound absorbing sound is transmitted. Piece 1 can function to absorb sound.

Preferably, in the above embodiment of the invention, the micropore has a local peak diameter of 0.3-0.7 nm, the mesopores have a local peak of 2-40 nm, and the macropore has a local peak of 0.1. -25 microns.

Optionally, the composite ceramic sound absorbing member has a specific surface area distribution ranging from 200 to 900 m ² /g. Preferably, the specific surface distribution ranges from 250 to 550 m ² /g.

Within the above parameters, the composite ceramic sound absorbing member has a better sound absorbing effect, and can more effectively reduce the F0 of the sounding device module.

In particular, the composite ceramic sound absorbing member provided by the present invention can be used in a sounding device module. The sound absorbing member is disposed in an area of the sounding device module capable of receiving sound, and may generally be a rear sound chamber of the module. Of course, the present invention does not specifically limit the application of the composite ceramic sound absorbing member. In other embodiments, the composite ceramic sound absorbing member can also be used in other devices that need to absorb sound.

The composite ceramic material sound absorbing member in the above embodiment has a porous structure in which pores of three different pore sizes, including micropores, mesopores and macropores, are contained. Filling it into the rear acoustic cavity of the speaker module, due to its high opening, interconnected porosity, uniform channel distribution, and developed specific surface area, the gas in the back cavity can be quickly adsorbed-desorbed, making resonance The space is virtualized to increase the low-frequency resonance frequency F0 of the module more effectively to ensure the low-frequency sound quality of the speaker module.

The porous composite ceramic material also has the advantages of good chemical stability, high temperature resistance, corrosion resistance, low density, low quality, low heat conduction performance, good mechanical strength and rigidity, high strength at room temperature and varying temperature.

On the other hand, the composite ceramic material sound absorbing member used in the invention is directly processed and formed in the synthesis process, and can be formed according to the specific shape of the acoustic cavity structure. The synthesis of other porous sound absorbing members has the advantages of simple process flow and simplified equipment, which reduces the production cost.

The invention also provides a sounding device module, which comprises a module housing, a sounding device unit and the above composite ceramic sound absorbing member. The sounding device unit and the composite ceramic sound absorbing member are disposed in the module housing. The sounding device is configured to generate sound and is transmitted from the sound outlet of the module housing. The composite ceramic sound absorbing member is located in the rear sound chamber or other position of the module housing for absorbing sound in the module housing.

While the invention has been described in detail with reference to the preferred embodiments of the present invention, it is understood that It will be appreciated by those skilled in the art that the above embodiments may be modified without departing from the scope and spirit of the invention. The scope of the invention is defined by the appended claims.

Claims

A composite ceramic sound absorbing member, characterized in that the composite ceramic sound absorbing member comprises a composite ceramic sound absorbing material, the composite ceramic sound absorbing material comprises microporous activated carbon and aluminum oxide, and the microporous activated carbon has micropores therein. The pores have a pore size ranging from 0.2 to 0.8 nm, the alumina has mesopores, the mesopores have a pore size ranging from 2 to 40 nm, and the composite ceramic sound absorbing member has large pores, and the large pores have a larger pore diameter than 0.1 micron.
The composite ceramic sound absorbing member according to claim 1, wherein the mass fraction of the microporous activated carbon in the composite ceramic sound absorbing material ranges from 15% to 75%, and the mass fraction of the alumina in the composite ceramic sound absorbing material The range is 20%-80%.
The composite ceramic sound absorbing member according to claim 1 or 2, wherein a modifier is added to the composite ceramic sound absorbing material, and the mass fraction of the modifier in the composite ceramic sound absorbing material ranges from 0.1% to 10%. The modifier includes at least one of chromium oxide, calcium oxide, and molybdenum oxide.
The composite ceramic sound absorbing member according to any one of claims 1 to 3, wherein the composite ceramic sound absorbing member comprises a macroporous member, and the composite ceramic sound absorbing material is configured to be attached to the large hole member. The large hole member has the large hole.
The composite ceramic sound absorbing member according to any one of claims 1 to 4, wherein the macroporous member is a carbon fiber skeleton, and the carbon fiber skeleton is configured to be completely or partially removed during preparation of the composite ceramic sound absorbing member. .
The composite ceramic sound absorbing member according to any one of claims 1 to 5, wherein the macroporous member is a foam, the foam has a pore structure, and the composite ceramic sound absorbing material is attached to the foam. The surface and the pore structure.
The composite ceramic sound absorbing member according to any one of claims 1 to 6, wherein the composite ceramic sound absorbing member is formed by curing a sound absorbing paste made of a composite ceramic sound absorbing material, and the sound absorbing slurry is added with hair. a foaming agent configured to generate bubbles in the sound absorbing slurry, and after the sound absorbing slurry is solidified, the pores formed at the bubbles constitute the large pores.
A composite ceramic sound absorbing member according to any one of claims 1 to 7, wherein The ceramic sound absorbing member is formed by curing a sound absorbing paste made of a composite ceramic sound absorbing material, and a gelling agent is added to the sound absorbing slurry, and the gelling agent is configured to increase the viscosity of the sound absorbing slurry. The sound absorbing slurry is configured to be solidified by mechanical agitation, and the bubbles in the sound absorbing slurry are formed into the large holes during mechanical stirring.
The composite ceramic sound absorbing member according to any one of claims 1 to 8, wherein the micropores have a local peak diameter of 0.3-0.7 nm, and the mesopores have a local peak of 2-40 nm. The macropore has a local peak diameter of 0.1-25 microns.
A sounding device module, comprising: a module housing and a sounding device unit, and the composite ceramic sound absorbing member according to any one of claims 1-9, wherein the sounding device unit and the composite ceramic sound absorbing member are disposed In the module housing.