JP2022150417A - Sound absorption device - Google Patents

Abstract

To provide a sound absorption device which does not need to be held by hands, reduces leakage of sound from the nose and can reduce sound emitted to the outside.SOLUTION: A sound absorption device 10 includes a cover part 11, a resonance type sound absorption part 12 and a porous sound absorption part 13. The cover part 11 is a container shape for covering the mouth and the nose of the face. The resonance type sound absorption part 12 forms a resonance space 25 in which inputted voice resonates on an inner side which is a face side of the cover part 11. The porous sound absorption part 13 is formed of a porous material and is provided on the face side of the resonance type sound absorption part 12.SELECTED DRAWING: Figure 1

Description

The present embodiment relates to a sound absorbing device, and more particularly to a sound absorbing device that absorbs sound emitted from the mouth.

2. Description of the Related Art In recent years, there has been a demand to reduce the diffusion of voices produced by the mouth during conversations, for example, due to requests for confidentiality and improvement of manners in public places. For example, the muffler disclosed in Patent Document 1 attempts to reduce the diffusion of sound emitted from the mouth by attenuating sound pressure using space. Patent Document 1 includes a funnel-shaped portion that is pressed against a portion of the face near the mouth, and a muffling cylinder through which sound is introduced from the funnel-shaped portion. The user presses the funnel-shaped portion on the face around the mouth and speaks toward it. As a result, the emitted sound is introduced into the muffling cylinder through the funnel-shaped portion, and the sound pressure is reduced.

However, in the case of Patent Document 1, the user has to hold the silencer with one hand. Therefore, the user always has to use one hand, making it difficult to work with both hands. In addition, in the case of Patent Document 1, the funnel-shaped portion only covers the periphery of the mouth on the face. Therefore, there is a problem that sound leaking from the nose cannot be reduced, and it is difficult to improve the sound absorbing performance.

JP-A-2002-244665

Accordingly, it is an object of the present invention to provide a sound absorbing device that does not require holding by hand, reduces sound leakage from the nose, and reduces sound emitted to the outside.

In this embodiment, the entire mouth and nose of the user's face are covered with the cover portion. Therefore, sound leakage from the nose as well as the mouth is reduced. Therefore, the sound absorbing performance is enhanced, and the sound emitted to the outside can be reduced. In addition, in the present embodiment, the resonance space of the resonance type sound absorbing portion is formed inside the cover portion, which is the face side, and the porous sound absorbing portion is formed on the face side of the resonance type sound absorbing portion. Prepare. That is, the resonance type sound absorbing part and the porous sound absorbing part that attenuate the sound emitted from the mouth and the sound leaking from the nose are overlapped inside the cover part. Therefore, the resonance type sound absorbing portion and the porous sound absorbing portion are integrated with the cover portion, and can be easily formed into a so-called mask shape together with the cover portion. As a result, the resonance type sound absorbing portion and the porous sound absorbing portion integrated with the cover portion can be easily attached to the face by using, for example, rubber cords or belts. Therefore, it becomes unnecessary to hold it by hand, and the user can easily perform work using both hands.

FIG. 2 is an exploded view showing the configuration of the sound absorbing device according to the first embodiment, and is a schematic perspective view of the sound absorbing device viewed from the face side; Schematic perspective view showing a state in which the sound absorbing device according to the first embodiment is worn on the face. Schematic view of the resonance type sound absorbing part of the sound absorbing device according to the first embodiment viewed from the face side Schematic cross-sectional view extracting a part for explaining the configuration of the sound absorbing device according to the first embodiment. FIG. 2 is a schematic diagram showing the action of the sound absorbing device according to the first embodiment, and is a diagram showing the relationship between frequency and sound absorption coefficient; FIG. 4 is a schematic diagram showing the action of the sound absorbing device according to the first embodiment, and is a diagram showing the relationship between the presence or absence of the sound absorbing device in an anechoic room and the amount of noise reduction; FIG. 4 is a schematic diagram showing the operation of the sound absorbing device according to the first embodiment, and is a diagram showing the relationship between the presence or absence of the sound absorbing device and the silencing volume in a normal environment; Schematic cross-sectional view extracting a part for explaining the configuration of the sound absorbing device according to the second embodiment. Schematic cross-sectional view extracting a part for explaining the configuration of the sound absorbing device according to the third embodiment.

A plurality of embodiments of the sound absorbing device will be described below with reference to the drawings. In addition, the same code|symbol is attached|subjected to the substantially same structural part in several embodiment, and description is abbreviate|omitted.
(First embodiment)
A sound absorbing device 10 according to the first embodiment shown in FIG. The sound absorbing device 10 is worn on the user's face 14 as shown in FIG. The sound absorbing device 10 is held on the user's face 14 using, for example, a belt 15 or a rubber cord. That is, the sound absorbing device 10 has a mask shape that covers the mouth and nose of the face 14 .

As shown in FIGS. 1 and 2 , the cover portion 11 is provided on the outermost side of the sound absorbing device 10 , that is, on the farthest side from the face 14 . The cover portion 11 is formed in a cup shape that covers the mouth and nose portions of the face 14 . In order to cover the mouth and nose, the cover part 11 is preferably shaped like a triangular container with rounded corners when viewed from the front, for example. In this manner, the cover portion 11 covers the mouth and nose portions of the face 14 and forms a space between the face 14 and the face 14 due to its cup-like shape. The cover part 11 can be formed using any material that can achieve its function, such as resin such as polyethylene, paper, metal, or wood. The sound absorbing device 10 absorbs sound emitted from the mouth and sound leaked from the nose. Hereinafter, the sound emitted from the mouth and the sound leaked from the nose are simply referred to as "spoken sounds".

The resonance type sound absorbing portion 12 has a bottom portion 21, a setting portion 22, a lid portion 23 and a connection hole portion 24 as shown in FIGS. The bottom portion 21 faces the inner side of the cover portion 11, that is, the surface on the face 14 side, as shown in FIG. The setting portion 22 rises from the face 14 side surface of the bottom portion 21 toward the face 14 side. That is, the setting portion 22 extends from the bottom portion 21 toward the face 14 side. The lid portion 23 is provided on the face 14 side of the setting portion 22 and forms a resonance space 25 with the bottom portion 21 . That is, the lid portion 23 sandwiches the setting portion 22 with the bottom portion 21 . Thereby, a distance corresponding to the setting portion 22 is secured between the bottom portion 21 and the lid portion 23 . The bottom portion 21 and the lid portion 23 form a resonance space 25 with a distance secured therebetween by the setting portion 22 . The connection hole portion 24 connects the surface of the lid portion 23 on the face 14 side and the resonance space 25 . That is, the connection hole portion 24 penetrates the lid portion 23 in the plate thickness direction.

The setting portion 22 is provided along the outer edge of the bottom portion 21 as shown in FIG. 3 and partitions the resonance space 25 into a plurality of resonance chambers 26 . That is, the setting portion 22 rises like a wall from the bottom portion 21 toward the face 14 side, and forms a closed resonance space 25 together with the bottom portion 21 and the lid portion 23 except for the connection hole portion 24 . The resonance space 25 is connected to the face 14 side of the lid portion 23 by a connection hole portion 24 penetrating the lid portion 23 . In the case of the first embodiment, the setting section 22 divides the resonance space 25 into a plurality of hexagonal resonance chambers 26 . By partitioning the resonance space 25 into hexagonal resonance chambers 26, the number of resonance chambers 26 accommodated per unit area can be increased. A connection hole portion 24 is provided corresponding to each resonance chamber 26 . That is, one connection hole portion 24 is connected to one resonance chamber 26 .

The resonance type sound absorbing portion 12 is made of an elastic material such as silicone rubber or polyurethane. That is, the bottom portion 21, the setting portion 22, and the lid portion 23, which constitute the resonance type sound absorbing portion 12, are all made of a flexible material having elasticity. The bottom portion 21 and the setting portion 22 that constitute the resonance type sound absorbing portion 12 are seamlessly and integrally formed by using, for example, a 3D printer. Further, the resonance type sound absorbing part 12 may be formed integrally with not only the bottom part 21 and the setting part 22 but also the lid part 23 by using a 3D printer. In this manner, the resonance type sound absorbing portion 12 is made of a flexible material having elasticity. Therefore, the resonance type sound absorbing portion 12 can be freely deformed according to the shape of the cup-shaped cover portion 11 while maintaining the resonance space 25 .

The resonance type sound absorbing portion 12 attenuates the vocalization introduced from the connection hole portion 24 by the configuration as described above. When the uttered sound enters the resonance space 25 through the connection hole 24 , it causes friction with the inner wall of the lid 23 forming the connection hole 24 . The energy of the vocalization is attenuated by the vibration of the air based on the vocalization causing friction with the inner wall of the lid portion 23 . Along with this, the energy of the vocalization is also attenuated by resonance in the resonance space 25 as the vocalization enters the resonance space 25 wider than the connection hole 24 . As a result, the sound pressure of the uttered sound is reduced in the resonance type sound absorbing portion 12 . Further, the frequency of sound attenuated by the resonance type sound absorbing portion 12 correlates with the volume of the resonance chamber 26 . Therefore, by adjusting the volume of the resonance chamber 26 based on the uttered sound, it is possible to attenuate the uttered sound in a specific frequency band according to the characteristics of the user's uttered sound.

The porous sound absorbing portion 13 is provided on the face 14 side of the resonance type sound absorbing portion 12 as shown in FIGS. The porous sound absorbing portion 13 is made of, for example, a foam material such as foamed polyurethane, or a nonwoven fabric of resin fibers such as polyester. In addition to the above examples, the porous sound absorbing portion 13 is not limited to resin, and may be made of metal, ceramics, or the like, in addition to paper or the like. Thus, the porous sound absorbing portion 13 is formed of a porous material having well-known sound absorbing properties. The porous sound absorbing portion 13 is provided on the side of the resonance type sound absorbing portion 12 close to the mouth, thereby absorbing the energy of the uttered sound before it enters the resonance type sound absorbing portion 12 . Further, since the resonance type sound absorbing portion 12 and the porous sound absorbing portion 13 have different sound absorbing mechanisms, the frequency bands of attenuated sound are different. Therefore, by combining the resonance type sound absorbing portion 12 and the porous sound absorbing portion 13, the uttered sound can be attenuated in a wider frequency band.

In the case of the first embodiment, the sound absorbing device 10 includes an inner portion 28 as shown in FIGS. 1 and 4. FIG. The inner portion 28 is provided between the resonance type sound absorbing portion 12 and the porous sound absorbing portion 13 . The inner portion 28 holds the resonance type sound absorbing portion 12 between itself and the cover portion 11 and holds the porous sound absorbing portion 13 on the face 14 side. That is, the inner portion 28 holds the resonance type sound absorbing portion 12 and the porous sound absorbing portion 13 housed inside the cover portion 11 and defines their positions. In addition, the inner portion 28 maintains the shape of the porous sound absorbing portion 13 and secures an appropriate distance between the porous sound absorbing portion 13 and the face 14 . The inner portion 28 is made of any material like the cover portion 11 .

The cover part 11 and the inner part 28 preferably have air holes for breathing. In the case of this embodiment, the air holes are provided in the inner portion 28 to ensure air passages to the face 14 . Specifically, the inner portion 28 has recesses 29 at positions corresponding to the left and right ends of the face 14 when viewed from the front. A portion of the outer edge of the inner portion 28 is recessed at a position corresponding to the recess 29 . The recess 29 forms a passageway between the face 14 and the inner portion 28 through which air for breathing flows. As a result, the user can easily breathe through an air hole formed between the recess 29 and the face 14 . The air hole portion is not limited to the example of the present embodiment described above, and may have a structure penetrating through the cover portion 11 and the inner portion 28, for example. The uttered sound tends to advance in the front direction with respect to the face 14 as a characteristic of the sound, and it is difficult to advance in the lateral direction of the face 14 . Therefore, even if the air holes formed by the concave portions 29 are provided at the left and right ends of the inner portion 28, the effect on the sound absorption performance of the sound absorbing device 10 as a whole is small.

Next, the performance of the sound absorbing device 10 configured as described above will be described.
(About sound absorption coefficient)
As shown in FIG. 5, the sound absorbing device 10 of the first embodiment, which includes the resonance type sound absorbing portion 12 and the porous sound absorbing portion 13, exhibits a high sound absorption coefficient over a wide range of frequency bands exceeding 500 Hz. As for the sound absorption coefficient, the normal incident sound absorption coefficient was measured. Example 1 in FIG. 5 is an example in which a polyester fiber nonwoven fabric is applied as the porous sound absorbing portion 13 . Further, Example 2 is an example in which foamed polyurethane is applied as the porous sound absorbing portion 13 . Both Example 1 and Example 2 exhibit high sound absorption coefficients in the frequency band exceeding 500 Hz. Further, it can be seen that the porous sound absorbing portion 13 has different sound absorbing characteristics depending on the material.

The sound absorption coefficient for each frequency in the resonance type sound absorber 12 correlates with the volume of the resonance chamber 26 . Therefore, by appropriately setting the volume of the resonance chamber 26, a high sound absorption coefficient can be achieved in a specific frequency band. Further, there is a difference between the resonance type sound absorbing portion 12 and the porous sound absorbing portion 13 in the characteristic of the sound absorption coefficient, that is, the frequency at which the sound absorption coefficient becomes high. Therefore, by adjusting the frequency characteristics of the resonance-type sound absorbing portion 12 in accordance with the frequency characteristics of the porous sound absorbing portion 13 determined by the material, for example, the sound absorption coefficient of vocalization can be increased in a wide frequency range.

(About silencing effect)
FIG. 6 shows the results of silencing in an anechoic room. In this test, in each frequency band, the sound pressure (dB) of uttered sound without the sound absorbing device 10 attached was compared with the sound pressure (dB) of leaked sound with the sound absorbing device 10 attached. The difference in sound pressure due to whether or not the sound absorbing device 10 is attached is taken as the silencing volume. As a result, it was found that the sound pressure decreased by about 10 to 20 dB in each frequency band when the sound absorbing device 10 was attached.

FIG. 7 shows the sound pressure (dB) of the uttered sound when the sound absorbing device 10 is not attached and the leaked sound when the sound absorbing device 10 is attached under a normal environment in which an air conditioner (not shown) operates. pressure (dB) was compared using a sound level meter. The set environment was one in which a sound of 46 dB was always measured due to the operation of the air conditioner. As a result, it was confirmed that the sound pressure decreased by an average of 12.7 dB when the sound absorbing device 10 was attached.

The average value of 50 dB measured with the sound absorbing device 10 attached is the same sound volume as the sound of rain in a library at midnight in a downtown area, for example. On the other hand, the average value of 63 dB measured with the sound absorbing device 10 worn is the volume of a general conversation. As a result, it can be seen that when the sound absorbing device 10 is worn, the sound is sufficiently absorbed to such an extent that conversation is not disturbing.

As described above, in the first embodiment, the mouth and nose of the user's face 14 are entirely covered with the cover portion 11 . Therefore, sound leakage from the nose as well as the mouth is reduced. Therefore, the sound absorbing performance is enhanced, and the sound emitted to the outside can be reduced.

Further, in the first embodiment, the resonance space 25 of the resonance type sound absorbing section 12 is formed inside the cover section 11 on the face 14 side, and the resonance type sound absorbing section 12 is formed of a porous material on the face 14 side. A porous sound absorbing portion 13 is provided. That is, the resonance-type sound absorbing portion 12 and the porous sound absorbing portion 13 that attenuate the sound emitted from the mouth and the sound leaking from the nose are stacked inside the cover portion 11 . Therefore, the resonance-type sound absorbing portion 12 and the porous sound absorbing portion 13 can easily be configured integrally with the cover portion 11 and can be easily formed into a so-called mask shape together with the cover portion 11 . As a result, the resonance-type sound absorbing portion 12 and the porous sound absorbing portion 13 integrated with the cover portion 11 can be easily attached to the face 14 by using the belt 15, a rubber cord, or the like. Therefore, it becomes unnecessary to hold it by hand, and the user can easily perform work using both hands.

(Second embodiment)
FIG. 8 shows the sound absorbing device 10 according to the second embodiment.
The structure of the sound absorbing device 10 of the second embodiment is simplified compared to that of the first embodiment.
In the case of the second embodiment, the resonance type sound absorbing portion 30 is configured integrally with the cover portion 11 . Specifically, the resonance type sound absorbing portion 30 has a setting portion 31 extending from the surface of the cover portion 11 on the face 14 side, ie, the inner surface, toward the face 14 . The setting portion 31 may be a wall portion that partitions the resonance chamber 26 into the resonance space 25, or may be simply columnar. For example, the setting unit 31 forms at least the peripheral portion defining the resonance space 25 in a wall shape, and sets the inner side thereof as the resonance space 25 . Further, the setting portion 31 may be a wall portion that partitions the resonance space 25 into a plurality of resonance chambers 26 as in the first embodiment. As a result, a resonance space 25 that is open on the face 14 side is formed on the face 14 side of the cover portion 11 .

The sound absorbing device 10 includes a porous sound absorbing portion 13 on the face 14 side of the resonance type sound absorbing portion 30 . The porous sound absorbing portion 13 is provided on the face 14 side of the setting portion 31 so as to cover the resonance space 25 on the face 14 side. Thereby, a resonance space 25 is formed between the cover portion 11 and the porous sound absorbing portion 13 with a distance secured by the setting portion 31 . Since the porous sound absorbing portion 13 is porous, it has fine holes (not shown). This hole connects the face 14 side of the porous sound absorbing portion 13 and the resonance space 25 . That is, the holes of the porous sound absorbing portion 13 correspond to the connection hole portions 24 in the first embodiment. Thus, a hole formed by the porous sound absorbing portion 13 is positioned between the face 14 and the resonance space 25 . Therefore, when the uttered sound passes through the porous sound absorbing portion 13, it is attenuated by the sound absorbing effect peculiar to the porous sound absorbing portion 13, and is attenuated by friction when entering the resonance space 25 and resonance in the resonance space 25. energy is attenuated.

In the second embodiment, the structure of the resonance type sound absorbing portion 30 is simplified. By setting the material forming the porous sound absorbing portion 13 and the volume of the resonance space 25 and the resonance chamber 26 of the resonance type sound absorbing portion 30, attenuation of the vocalization in a desired frequency band can be achieved. Therefore, it is possible to secure the sound absorption performance while being thinner and lighter.

(Third Embodiment)
FIG. 9 shows a sound absorbing device according to the third embodiment.
The structure of the sound absorbing device 10 of the third embodiment is simplified compared to that of the first embodiment.
In the case of the third embodiment, the resonance type sound absorbing section 40 does not have a member corresponding to the lid section 23 of the first embodiment. Specifically, the resonance type sound absorbing part 40 has a bottom part 41 and a setting part 42 . These bottom part 41 and setting part 42 are preferably integrally formed by a 3D printer or the like as in the first embodiment. As a result, the resonance type sound absorbing section 40 is partitioned by the bottom section 41 and the setting section 42 to form a resonance space 25 that is open on the face 14 side. The resonance space 25 may be partitioned into a plurality of resonance chambers 26 by the setting section 42 .

The sound absorbing device 10 includes the porous sound absorbing portion 13 on the face 14 side of the resonance type sound absorbing portion 40 . The porous sound absorbing portion 13 is provided on the face 14 side of the setting portion 42 so as to cover the resonance space 25 on the face 14 side. Thereby, a resonance space 25 is formed between the bottom portion 41 and the porous sound absorbing portion 13 with a distance secured by the setting portion 42 . The porous sound absorbing portion 13 has fine holes corresponding to the connecting hole portions 24 as in the second embodiment. Thus, a hole formed by the porous sound absorbing portion 13 is positioned between the face 14 and the resonance space 25 . Therefore, when the uttered sound passes through the porous sound absorbing portion 13, it is attenuated by the sound absorbing effect peculiar to the porous sound absorbing portion 13, and is attenuated by friction when entering the resonance space 25 and resonance in the resonance space 25. energy is attenuated.

In the third embodiment, the structure of the resonance type sound absorber 40 is simplified. By setting the material forming the porous sound absorbing portion 13, the volume of the resonance space 25 of the resonance type sound absorbing portion 40, and the like, it is possible to attenuate the uttered sound in a desired frequency band. Further, in the third embodiment, the precision of the resonance space 25 is improved by providing the bottom portion 41 and the setting portion 42 in the resonance type sound absorbing portion 40 . Therefore, it is possible to secure the sound absorbing performance while configuring the device to be thinner and lighter.

(Other embodiments)
The present invention described above is not limited to the above embodiments, and can be applied to various embodiments without departing from the scope of the present invention.
For example, in the multiple embodiments described above, a microphone or the like capable of wired or wireless communication may be provided inside the cover portion 11 . The vocalized sound collected by the microphone is transmitted to, for example, a mobile terminal. As a result, it is possible to have a conversation through the microphone while reducing the leakage of the uttered sound from the sound absorbing device 10 . In this case, the microphone (not shown) may be provided outside the cover portion 11, and the sound entrance side of the sound absorbing device 10, that is, the side near the face 14 of the sound absorbing device 10, and the sound exit side of the sound absorbing device 10, that is, the sound absorbing device 10 may be provided at any position, such as the side close to the cover portion 11, as long as the sound can be obtained. In addition, since the sound absorbing device 10 touches the face 14, the cover portion 11, the resonance type sound absorbing portion 12, the porous sound absorbing portion 13, and the inner portion 28 can be disassembled and cleaned in consideration of hygiene. It is possible. In this case, the cover portion 11, the resonance-type sound absorbing portion 12, the porous sound absorbing portion 13, and the inner portion 28 may be subjected to antibacterial treatment using, for example, a photocatalyst or metal ions, for all or part of them.

In the drawings, 10 is a sound absorbing device, 11 is a cover portion, 12, 30 and 40 are resonance type sound absorbing portions, 13 is a porous sound absorbing portion, 21 and 41 are bottom portions, 22, 31 and 42 are setting portions, and 23 is a lid portion. , 24 is a connecting hole, 25 is a resonance space, and 26 is a resonance chamber.

Claims (6)

a container-shaped cover covering the mouth and nose of the face;
a resonator-type sound absorbing portion that forms a resonance space in which an input sound resonates inside the cover portion on the face side;
a porous sound absorbing portion formed of a porous material and provided on the face side of the resonator type sound absorbing portion;
A sound absorber with The resonator-type sound absorbing part has a setting part that extends from the cover part toward the face side and sets the resonance space between the cover part and the setting part,
2. The sound absorbing device according to claim 1, wherein the porous sound absorbing portion forms the resonance space with the cover portion with the setting portion interposed therebetween. The resonator-type sound absorbing part has a bottom part facing the face-side surface of the cover part, and a setting part extending from the bottom part toward the face side and defining the resonance space between the bottom part and the bottom part,
2. The sound absorbing device according to claim 1, wherein the porous sound absorbing portion forms the resonance space with the bottom portion with the setting portion interposed therebetween. The resonator-type sound absorbing part is
a bottom portion facing the face side surface of the cover portion; a setting portion extending from the bottom portion toward the face side; a lid portion forming the resonance space between the setting portion and the bottom portion; a connection hole connecting the surface of the lid on the face side and the surface on the resonance space side;
The sound absorbing device of claim 1, comprising: 5. The sound absorbing device according to claim 4, wherein the setting portion has a wall shape that partitions the resonance space into a plurality of resonance chambers. 6. The sound absorbing device according to claim 4, wherein the resonator-type sound absorbing portion is made of a soft material that conforms to the face and the surface of the cover portion on the face side.

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