Sound suppression tool

Abstract

To provide a sound suppression tool with which it is possible to adjust a frequency range in which sounds are to be suppressed.SOLUTION: A sound suppression tool 100 mounted to the mouth of a user and covering the mouth of the user includes a resonance unit 20 provided with a protective part 10 having a through-hole 12, and a resonance part (first resonance part 21, second resonance part 22, third resonance part 23) attachable to the protective part 10. The resonance unit includes a tube part (first tube part 211, second tube part 221, third tube part 231), of which an end on the Y-axis positive direction side is open to the outside air and an end on the Y-axis negative direction side is connected to the through-hole 12, and a Helmholtz resonator (first neck part 212 and first resonance tube 213, second neck part 222 and second resonance tube 223, third neck part 232 and third resonance tube 233) having a space communicating with the internal space of the tube part. The protective part 10 is configured to be capable of attaching at least two or more types of Helmholtz resonant tubes differing in resonator capacity in an interchangeable manner.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present invention relates to a sound-reducing device. [Background technology]

[0002] BACKGROUND ART Conventionally, masks that can provide an attenuation effect (sound reduction effect) of the sound emitted from a person's mouth when making a call in a public space or the like have been known (for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2017-2446 Summary of the Invention [Problem to be solved by the invention]

[0004] However, there is a demand for such a mask to provide sound reduction suited to the pitch of the user's voice and the environment in which it is used. Patent Document 1 does not address this demand.

[0005] SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a sound reduction device that can adjust the frequency range in which sound is reduced. [Means for solving the problem]

[0006] The sound-reducing device of the present invention comprises a protective part having a through hole and a resonating part that can be attached to the protective part, the resonating part comprising a tube part having one end open to the outside air and the other end connected to the through hole, and a resonator having a space communicating with the internal space of the tube part, and the protective part is configured to allow the attachment of at least two or more types of resonating parts with different resonator capacities. [Effects of the Invention]

[0007] According to the present invention, the frequency range in which sound is reduced can be adjusted. [Brief explanation of the drawings]

[0008] [Figure 1] 10A and 10B are diagrams showing an example of use of a sound reduction device of a third form according to the present embodiment. [Figure 2] FIG. 10 is a perspective view showing the external appearance of the sound reduction device of the third embodiment, including the Y-axis positive side. [Figure 3] FIG. 10 is a perspective view showing the external appearance of the protection part including the negative Y-axis direction side. [Figure 4] 10 is a cross-sectional view of the sound reduction device of the third embodiment cut along the YZ plane passing through the center in the X-axis direction. FIG. [Figure 5A] FIG. 2 is a perspective view showing the external appearance of the sound reduction device of the first embodiment, including the Y-axis positive side. [Figure 5B] 3 is a cross-sectional view of the sound reduction device of the first embodiment cut along the YZ plane passing through the center in the X-axis direction. FIG. [Figure 5C] 1A and 1B are diagrams showing an example of use of the sound reduction device of the first form. [Figure 6A] FIG. 10 is a perspective view showing the external appearance of the sound reduction device of the second embodiment, including the Y-axis positive side. [Figure 6B] 10 is a cross-sectional view of the sound reduction device of the second embodiment cut along the YZ plane passing through the center in the X-axis direction. FIG. [Figure 6C] 10A and 10B are diagrams showing an example of use of the sound reduction device of the second form. [Figure 7] 10A and 10B are diagrams illustrating the sound reduction effect of the sound reduction device of the first embodiment. [Figure 8] 10A and 10B are diagrams showing the sound reduction effect of the sound reduction device of the second embodiment. [Figure 9] 10A and 10B are diagrams showing the sound reduction effect of the sound reduction device of the third embodiment. [Figure 10] 10 is a cross-sectional view of the sound reduction device of Modification 1 cut along the YZ plane passing through the center in the X-axis direction. FIG. [Figure 11] FIG. 11 is a perspective view showing the external appearance of the sound reduction device of Modification 2, including the Y-axis positive side. [Figure 12] 10 is a side view showing the external appearance of the sound reduction device of Modification 2, including the negative X-axis direction side. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. As shown in FIG. 1 , a sound reduction device 100 according to this embodiment is worn on a user's mouth and covers the user's mouth. The sound reduction device 100 reduces sounds, including those emitted by the user, using the Helmholtz resonance principle. The sound reduction device 100 may include a microphone and collect sounds using the microphone. Therefore, the sound reduction device 100 can collect sounds using the microphone so that the user's voice cannot be heard by people nearby. For example, when holding a remote conference in an office or at home, the sound reduction device 100 can reduce the user's voice from being heard by people nearby, thereby preventing the content of the conversation from being known by people nearby or causing discomfort to people nearby.

[0010] The sound reduction device 100 of this embodiment is worn on the user's mouth inside the cover mask 200. This reduces the visual discomfort caused by wearing the sound reduction device 100. When the cover mask 200 is made of a material with a high sound insulation effect (thick cloth, rubber sheet layer, etc.), using the cover mask 200 together with the sound reduction device 100 can further reduce sound. Furthermore, when the cover mask 200 is made of a breathable material (mesh, nonwoven fabric, etc.), comfort can be obtained when using the cover mask 200. The sound reduction device 100 may be held by the user and worn on the user's mouth, or may have a band or the like for wearing the sound reduction device 100 on the user's head.

[0011] The sound reduction device 100 includes a protective portion 10 and a resonance tube unit 20 that can be attached to the protective portion 10. The protective portion 10 is provided at a portion of the sound reduction device 100 that is attached to the user's mouth. The protective portion 10 is made of various soft materials with relatively low hardness, such as silicone. As shown in FIGS. 2 and 3 , the protective portion 10 has a cylindrical shape with a bottom, and a cross section parallel to the XZ plane that is elliptical. As shown in FIG. 4 , the protective portion 10 has a flat bottom portion 10a that is parallel to the XZ plane, a cylindrical first portion 10b that is positioned on the negative Y-axis direction side from the periphery of the bottom portion 10a and extends in the negative Y-axis direction, and a second portion 10c that extends in the negative Y-axis direction from the negative Y-axis end of the first portion 10b and has a tube diameter that narrows as it moves in the negative Y-axis direction. The second portion 10c has an opening 11 at its end on the negative Y-axis direction. The opening 11 is positioned to surround the user's mouth when the sound reduction device 100 is worn in the user's mouth. In other words, when the sound reduction device 100 is worn in the user's mouth, the user's mouth is positioned within the opening 11 of the protective part 10 and is covered by the sound reduction device 100.

[0012] The bottom portion 10a is provided with a through-hole 12 that penetrates the bottom portion 10a in the Y-axis direction and communicates with the outside of the sound reduction device 100 via the resonance tube unit 20. The bottom portion 10a is also provided with a microphone 13 for collecting sounds, including the voice of a user wearing the sound reduction device 100. In other words, the protective unit 10 is equipped with the microphone 13 inside. The microphone 13 is connected to a signal processing circuit and a communication IF (Interface), not shown, and the results of signal processing by the signal processing circuit may be transmitted to an external device via the communication IF.

[0013] The resonance tube unit 20 includes a first resonance portion 21, a second resonance portion 22, and a third resonance portion 23. The first resonance portion 21, the second resonance portion 22, the third resonance portion 23, and the protective portion 10 are connected in this order from the positive direction of the Y axis to form a sound-reducing device 100. The sound-reducing device 100 formed by connecting the first resonance portion 21, the second resonance portion 22, the third resonance portion 23, and the protective portion 10 is referred to as a sound-reducing device 100 of a third embodiment. The first resonance portion 21 and the second resonance portion 22 are each configured to be directly connectable to the protective portion 10. Therefore, as shown in FIGS. 5A and 5B , the sound-reducing device 100 may be formed by connecting the first resonance portion 21 and the protective portion 10 in this order from the positive direction of the Y axis. The sound-reducing device 100 formed by connecting the first resonance portion 21 and the protective portion 10 is referred to as a sound-reducing device 100 of a first embodiment. 6A and 6B, the sound-reducing device 100 may be configured by connecting the first resonance part 21, the second resonance part 22, and the protective part 10 in this order from the positive direction of the Y-axis. The sound-reducing device 100 configured by connecting the first resonance part 21, the second resonance part 22, and the protective part 10 is referred to as a second form of sound-reducing device 100. In other words, the protective part 10 is configured to be replaceable with at least two or more types of resonance parts (the first resonance part 21, the second resonance part 22, and the third resonance part 23) having resonators (described below) with different capacities.

[0014] The first resonance unit 21 includes a first pipe portion 211, a first neck portion 212, and a first resonance tube 213. The first resonance tube 213 has a bottomed cylindrical shape with a bottom portion 213a, and a cross section parallel to the XZ plane is circular. The first pipe portion 211 is disposed within the first resonance tube 213 at the center of the first resonance tube 213 in the X-axis direction and on the positive side of the center in the Z-axis direction. The first pipe portion 211 may also be disposed within the first resonance tube 213 at the center in the Z-axis direction. The first pipe portion 211 is a hollow tube with a circular internal cross section extending in the Y-axis direction, and penetrates the first resonance tube 213 in the Y-axis direction. The inner diameter of the first pipe portion 211 is approximately the same as the inner diameter of the through hole 12 of the protection unit 10. The first pipe portion 211 is in communication with the first resonance tube 213 via the first neck portion 212.

[0015] The second resonance unit 22 includes a second pipe portion 221, a second neck portion 222, and a second resonance tube 223. The second resonance tube 223 has a cylindrical shape with a bottom portion 223a and a circular cross section parallel to the XZ plane. The diameter of the second resonance tube 223 is larger than the diameter of the first resonance tube 213. The second pipe portion 221 is disposed within the second resonance tube 223 at the center of the second resonance tube 223 in the X-axis direction and on the positive side of the center in the Z-axis direction. The second pipe portion 221 may also be disposed within the second resonance tube 223 at the center in the Z-axis direction. The second pipe portion 221 is a hollow tube with a circular internal cross section extending in the Y-axis direction, and penetrates the second resonance tube 223 in the Y-axis direction. The inner diameter of the second pipe portion 221 is approximately the same as the inner diameter of the through hole 12 of the protection unit 10 and the inner diameter of the first pipe portion 211. The second pipe portion 221 communicates with a second resonance pipe 223 via a second neck portion 222 .

[0016] The third resonance unit 23 includes a third pipe portion 231, a third neck portion 232, and a third resonance tube 233. The third resonance tube 233 has a bottomed cylindrical shape with a bottom portion 233a, and a cross section parallel to the XZ plane that is elliptical. The major and minor axes of the third resonance tube 233 are larger than the diameter of the second resonance tube 223. The bottom portion 233a has substantially the same shape as the bottom portion 10a of the protective unit 10. The third pipe portion 231 is disposed within the third resonance tube 233 at the center of the third resonance tube 233 in the X-axis direction and on the positive side of the center in the Z-axis direction. Note that the third pipe portion 231 may also be disposed at the center in the Z-axis direction within the third resonance tube 233. The third pipe portion 231 is a hollow pipe that extends in the Y-axis direction and has a circular internal cross section, and penetrates the third resonance tube 233 in the Y-axis direction. The inner diameter of the third pipe section 231 is approximately the same as the inner diameter of the through hole 12 of the protective section 10, the inner diameter of the first pipe section 211, and the second pipe section 221. The third pipe section 231 communicates with the third resonance pipe 233 via the third neck section 232.

[0017] In the sound reduction device 100 of the first embodiment, as shown in FIG. 5A , the first resonator 21 is connected to the protective unit 10 so that a mark M1, serving as alignment means provided on a side surface of the first resonance tube 213, is located furthest to the positive side in the Z-axis direction. By providing the mark M1 on the first resonator 21, the first pipe portion 211 of the first resonator 21 and the through hole 12 of the protective unit 10 can be easily positioned so that they overlap with each other in the Z-axis direction. Furthermore, in the sound reduction device 100 of the first embodiment, the first pipe portion 211 of the first resonator 21 and the through hole 12 of the protective unit 10 are positioned at different positions in the Y-axis direction. In other words, the end of the first pipe portion 211 on the positive side in the Y-axis direction is open to the outside air, and the end of the first pipe portion 211 on the negative side in the Y-axis direction is connected to the through hole 12, so that the internal space of the first pipe portion 211 and the through hole 12 of the protective unit 10 are in communication with each other. Therefore, the outside of the sound reduction device 100 of the first form and the inside of the protective part 10 are in communication with each other via the first pipe part 211 and the through-hole 12. This allows the air blown out of the user's mouth to be released into the space outside the sound reduction device 100 of the first form when the user has the protective part 10 of the sound reduction device 100 of the first form tightly attached to the periphery of the mouth. In other words, when the user is wearing the sound reduction device 100 of the first form and is speaking, the air blown out of the user's mouth can be released into the space outside the sound reduction device 100 of the first form, thereby reducing the feeling of breathlessness felt by the user when wearing the sound reduction device 100 of the first form.

[0018] 5C, the through holes 12 are provided at a position facing the user's mouth when the user is wearing the sound reduction device 100. As a result, air blown out from the user's mouth when the user is speaking can be released into the space outside the first form of sound reduction device 100 via the through holes 12 and the first pipe portion 211 that are arranged in a straight line at a position facing the user's mouth. This makes it possible to further reduce the sense of breathlessness felt when the user is wearing the first form of sound reduction device 100.

[0019] Furthermore, in the sound reduction device 100 of the first embodiment, the end of the first resonance pipe 213 on the negative Y-axis direction side is connected to the bottom 10a of the protective part 10. As a result, the first resonance pipe 213 is formed to surround the first air chamber A1 together with the bottom 10a. In other words, the first resonance pipe 213 and the protective part 10 form the first air chamber A1.

[0020] When the sound reduction device 100 of the first form is worn by a user's mouth and the user speaks, the sound enters the first tube portion 211 from the negative Y-axis direction side through the through-hole 12. A resonance sound corresponding to a wavelength according to the capacity of the first air chamber A1 is generated within the first air chamber A1. At the joint 212a between the first tube portion 211 and the first neck portion 212 (the end of the first neck portion 212 on the positive Z-axis direction side), the sound (incident sound) incident from the first tube portion 211 to the first neck portion 212 interferes with the resonance sound (outgoing sound) generated within the first air chamber A1, thereby canceling out the frequency sound according to the capacity of the first air chamber A1. In other words, the first neck portion 212 and the first resonance tube 213 form a Helmholtz resonator. As a result, sound of a frequency (resonant frequency) according to the capacity of the first air chamber A1 is attenuated and emitted at the outlet (the end of the first pipe portion 211 on the positive Y-axis direction side) of the first pipe portion 211. In other words, in the sound reduction device 100 of the first form, sound emitted by the user is emitted to the outside of the sound reduction device 100 with the frequency sound according to the capacity of the first air chamber A1 attenuated.

[0021] The horizontal axis of the graph shown in Fig. 7 is the frequency of the sound, and the vertical axis is decibels (dB). Graph B1 shown in Fig. 7 is the result of observing sound from a sine wave sweep sound source of 100 Hz to 3 kHz without using the sound reduction device 100. Graph B2 shown in Fig. 7 is the result of observing the sound that was incident on the inside of the protective part 10 of the sound reduction device 100 of the first form and was emitted from the outlet of the first pipe part 211. Comparing graphs B1 and B2, it is clear that the sound is attenuated in the frequency range above about 700 Hz.

[0022] In the sound reduction device 100 of the second embodiment, as shown in FIG. 6A , the second resonance unit 22 is connected to the protective unit 10 so that mark M2, which serves as alignment means and is provided on the front surface (the surface on the Y-axis positive side) of the second resonance tube 223, is located furthest toward the Z-axis positive side. Furthermore, the first resonance unit 21 is connected to the second resonance unit 22 so that mark M1 is located furthest toward the Z-axis positive side and so that mark M1 and mark M2 overlap with each other in the X-axis direction. Since the first resonance unit 21 has mark M1 and the second resonance unit 22 has mark M2, the first pipe portion 211 of the first resonance unit 21, the second pipe portion 221 of the second resonance unit 22, and the through hole 12 of the protective unit 10 can be easily positioned to overlap with each other in the Z-axis direction. Furthermore, the first pipe portion 211 of the first resonance unit 21, the second pipe portion 221 of the second resonance unit 22, and the through hole 12 of the protective unit 10 are positioned at different positions in the Y-axis direction. That is, the end of the first pipe portion 211 on the positive side of the Y axis is open to the outside air, the end of the first pipe portion 211 on the negative side of the Y axis is connected to the end of the second pipe portion 221 on the positive side of the Y axis, and the end of the second pipe portion 221 on the negative side of the Y axis is connected to the through hole 12. The internal spaces of the first pipe portion 211 and the second pipe portion 221 are in communication with the through hole 12 of the protective portion 10. Therefore, the outside of the sound reduction device 100 of the second form is in communication with the inside of the protective portion 10 by the first pipe portion 211, the second pipe portion 221, and the through hole 12. This allows the user to release air blown from the user's mouth into the space outside the sound reduction device 100 of the second form, with the protective portion 10 of the second form in close contact with the periphery of the mouth. In other words, when a user is wearing the second form of sound-reducing device 100 and is speaking, the air blown out of the user's mouth can be released into the space outside the second form of sound-reducing device 100, thereby reducing the sense of breathlessness felt by the user when wearing the second form of sound-reducing device 100.

[0023] 6C, the through-holes 12 are provided at a position facing the user's mouth when the user is wearing the sound reduction device 100. As a result, air blown out from the user's mouth when the user is speaking can be released into the space outside the second form of sound reduction device 100 via the through-holes 12, the first pipe portion 211, and the second pipe portion 221, which are arranged in a straight line at a position facing the user's mouth. This makes it possible to further reduce the sense of breathlessness felt by the user when wearing the second form of sound reduction device 100.

[0024] In the sound reduction device 100 of the second embodiment, the end of the first resonance pipe 213 on the negative Y-axis direction side is connected to the bottom 223a of the second resonance pipe 223. As a result, the first resonance pipe 213 is formed to surround the first air chamber A1 together with the bottom 223a. In other words, the first resonance pipe 213 and the second resonance pipe 223 form the first air chamber A1. In the sound reduction device 100 of the second embodiment, the end of the second resonance pipe 223 on the negative Y-axis direction side is connected to the bottom 10a of the protective part 10. As a result, the second resonance pipe 223 is formed to surround the second air chamber A2 together with the bottom 10a. In other words, the second resonance pipe 223 and the protective part 10 form the second air chamber A2. The volume of the second air chamber A2 is larger than the volume of the first air chamber A1. Therefore, the sound reduction device 100 of the second embodiment includes a plurality of types of resonance parts (first resonance part 21, second resonance part 22) having different resonator capacities.

[0025] When the sound reduction device 100 of the second form is worn by a user's mouth and the user speaks, the sound enters the second tube portion 221 from the negative Y-axis direction through the through-hole 12. A resonance sound corresponding to a wavelength corresponding to the capacity of the second air chamber A2 is generated in the second air chamber A2. At the joint 222a between the second tube portion 221 and the second neck portion 222 (the end of the second neck portion 222 on the positive Z-axis direction side), the sound (incident sound) entering the second neck portion 222 from the second tube portion 221 interferes with the resonance sound (outgoing sound) generated in the second air chamber A2, canceling out the frequency sound corresponding to the capacity of the second air chamber A2. In other words, the second neck portion 222 and the second resonance tube 223 form a Helmholtz resonator. As a result, at the outlet of the second pipe 221 (the end of the second pipe 221 on the positive Y-axis direction side), sound of a frequency corresponding to the capacity of the second air chamber A2 is attenuated and emitted. Next, sound, of which the frequency sound corresponding to the capacity of the second air chamber A2 has been attenuated, enters the inside of the first pipe 211 from the outlet of the second pipe 221. As with the sound reduction device 100 of the first form, at the outlet of the first pipe 211 (the end of the first pipe 211 on the positive Y-axis direction side), sound of a frequency corresponding to the capacity of the first air chamber A1 is attenuated and emitted. In other words, in the sound reduction device 100 of the second form, sound emitted by the user is attenuated at the frequency sound corresponding to the capacity of the first air chamber A1 and the frequency (resonant frequency) sound corresponding to the capacity of the second air chamber A2, and is emitted to the outside of the sound reduction device 100.

[0026] Furthermore, in the sound reduction device 100 of the second form, the distance over which sound entering through the through hole 12 travels until it is emitted from the outlet of the first pipe portion 211 is longer by the length of the second pipe portion 221 in the Y-axis direction, compared to the sound reduction device 100 of the first form. Therefore, by using the sound reduction device 100 of the second form, a higher sound reduction effect can be obtained than by using the sound reduction device 100 of the first form. Note that when a user wears the sound reduction device 100 of the second form and speaks, air blown out of the user's mouth passes through the first pipe portion 211 and the second pipe portion 221, which are arranged in a straight line from the through hole 12 to the outlet of the first pipe portion 211. The combined length of the first pipe portion 211 and the second pipe portion 221 in the Y-axis direction is, for example, 5 cm. Therefore, the sense of breathlessness felt by the user when wearing the sound reduction device 100 of the second form can be reduced.

[0027] The horizontal axis of the graph shown in FIG. 8 is the frequency of the sound, and the vertical axis is decibels (dB). Graph B1 shown in FIG. 8 is the same as graph B1 shown in FIG. 7. Graph B3 shown in FIG. 8 is the result of observing the sound that was incident on the inside of the protective section 10 of the sound reduction device 100 of the second embodiment and was output from the outlet of the first pipe section 211. Comparing graphs B1 and B3, it is clear that the sound is attenuated in the frequency range of about 400 Hz or higher. In this way, in the sound reduction device 100 of the second embodiment, by connecting the first resonating section 21 and the second resonating section 22 to form air chambers of different capacities (first air chamber A1, second air chamber A2), the frequency range in which sound is reduced can be broadened compared to the sound reduction device 100 of the first embodiment.

[0028] 2, in the sound reduction device 100 of the third embodiment, the second resonance portion 22 is connected to the third resonance portion 23 so that the mark M2 is located furthest on the positive side of the Z axis. The first resonance portion 21 is connected to the second resonance portion 22 so that the mark M1 is located furthest on the positive side of the Z axis and so that the marks M1 and M2 overlap with each other in the X axis direction. Since the first resonance portion 21 has the mark M1 and the second resonance portion 22 has the mark M2, the first pipe portion 211 of the first resonance portion 21, the second pipe portion 221 of the second resonance portion 22, the third pipe portion 231 of the third resonance portion 23, and the through hole 12 of the protection portion 10 can be easily arranged in positions that overlap with each other in the Z axis direction. Furthermore, the first pipe portion 211 of the first resonance portion 21, the second pipe portion 221 of the second resonance portion 22, the third pipe portion 231 of the third resonance portion 23, and the through hole 12 of the protective portion 10 are arranged at different positions in the Y-axis direction. That is, the end of the first pipe portion 211 on the positive Y-axis direction side is open to the outside air, the end of the first pipe portion 211 on the negative Y-axis direction side is connected to the end of the second pipe portion 221 on the positive Y-axis direction side, the end of the second pipe portion 221 on the negative Y-axis side is connected to the end of the third pipe portion 231 on the positive Y-axis direction side, and the end of the third pipe portion 231 on the negative Y-axis side is connected to the through hole 12. The internal spaces of the first pipe portion 211, the second pipe portion 221, and the third pipe portion 231 are in communication with the through hole 12 of the protective portion 10. Therefore, the outside of the sound reduction device 100 of the third form and the inside of the protective part 10 are in communication with each other via the first pipe part 211, the second pipe part 221, the third pipe part 231 and the through-hole 12. This allows the user, with the protective part 10 of the sound reduction device 100 of the third form in close contact with the periphery of the mouth, to release air blown out of the user's mouth into the space outside the sound reduction device 100 of the third form. In other words, when the user is wearing the sound reduction device 100 of the third form and speaking, air blown out of the user's mouth can be released into the space outside the sound reduction device 100 of the third form, thereby reducing the feeling of breathlessness felt by the user when wearing the sound reduction device 100 of the third form.

[0029] 1, the through-holes 12 are provided at a position facing the user's mouth when the user is wearing the sound reduction device 100. As a result, air blown out from the user's mouth when the user is speaking can be released into the space outside the sound reduction device 100 of the third form via the through-holes 12, the first pipe portion 211, the second pipe portion 221, and the third pipe portion 231, which are arranged in a straight line at a position facing the user's mouth. This makes it possible to further reduce the sense of breathlessness felt by the user when wearing the sound reduction device 100 of the third form.

[0030] In the sound reduction device 100 of the third embodiment, the first resonance pipe 213 and the second resonance pipe 223 form the first air chamber A1, similar to the sound reduction device 100 of the second embodiment. In the sound reduction device 100 of the third embodiment, the end of the second resonance pipe 223 on the negative Y-axis direction side is connected to the bottom 233a of the third resonance pipe 233. As a result, the second resonance pipe 223 is formed to surround the second air chamber A2 together with the bottom 233a. In other words, the second resonance pipe 223 and the third resonance pipe 233 form the second air chamber A2. In the sound reduction device 100 of the third embodiment, the end of the third resonance pipe 233 on the negative Y-axis direction side is connected to the bottom 10a of the protective part 10. As a result, the third resonance pipe 233 is formed to surround the third air chamber A3 together with the bottom 10a. That is, the third resonance pipe 233 and the protective part 10 form a third air chamber A3. The capacity of the third air chamber A3 is larger than the capacity of the first air chamber A1 and the capacity of the second air chamber A2. Therefore, the sound reduction device 100 of the third form includes multiple types of resonance parts (first resonance part 21, second resonance part 22, third resonance part 23) with different resonator capacities.

[0031] When the sound reduction device 100 of the third embodiment is worn by a user and the user speaks, the sound enters the third tube portion 231 from the negative Y-axis direction through the through-hole 12. A resonance sound corresponding to a wavelength corresponding to the capacity of the third air chamber A3 is generated within the third air chamber A3. At the joint 232a between the third tube portion 231 and the third neck portion 232 (the end of the third neck portion 232 on the positive Z-axis direction side), the sound entering the third neck portion 232 from the third tube portion 231 (incident sound) interferes with the resonance sound generated within the third air chamber A3 (outgoing sound), thereby canceling out the frequency sound corresponding to the capacity of the third air chamber A3. In other words, the third neck portion 232 and the third resonance tube 233 form a Helmholtz resonator. As a result, at the outlet of the third pipe section 231 (the end on the positive Y-axis direction side of the third pipe section 231), sound with a frequency corresponding to the capacity of the third air chamber A3 is attenuated and emitted. Next, sound with the frequency corresponding to the capacity of the third air chamber A3 attenuated enters the inside of the second pipe section 221 from the outlet of the third pipe section 231. As with the sound reduction device 100 of the second form, at the outlet of the second pipe section 221 (the end on the positive Y-axis direction side of the second pipe section 221), sound with a frequency corresponding to the capacity of the second air chamber A2 is attenuated and emitted. Next, sound with the frequency corresponding to the capacity of the second air chamber A2 and the frequency corresponding to the capacity of the third air chamber A3 attenuated enters the inside of the first pipe section 211 from the outlet of the second pipe section 221. As with the sound reduction device 100 of the first embodiment, at the outlet of the first pipe portion 211 (the end portion on the Y-axis positive side of the first pipe portion 211), sound of a frequency corresponding to the capacity of the first air chamber A1 is attenuated and emitted. That is, in the sound reduction device 100 of the third embodiment, sound emitted by the user is attenuated with frequency sounds corresponding to the capacity of the first air chamber A1, frequency sounds corresponding to the capacity of the second air chamber A2, and frequency sounds (resonant frequencies) corresponding to the capacity of the third air chamber A3, and emitted to the outside of the sound reduction device 100. Furthermore, in the sound reduction device 100 of the third embodiment, the distance over which sound incident from the through hole 12 travels until it is emitted from the outlet of the first pipe portion 211 is longer by the length of the third pipe portion 231 in the Y-axis direction, compared to the sound reduction device 100 of the second embodiment. Therefore, by using the sound reduction device 100 of the third embodiment, a greater sound reduction effect can be obtained than by using the sound reduction device 100 of the second embodiment.

[0032] The horizontal axis of the graph shown in FIG. 9 is the frequency of the sound, and the vertical axis is decibels (dB). Graph B1 shown in FIG. 9 is the same as graph B1 shown in FIG. 7. Graph B4 shown in FIG. 9 is the result of observing the sound entering the protective section 10 of the sound reduction device 100 of the third embodiment and outputting it from the outlet of the first pipe section 211. Comparing graphs B1 and B4, it is clear that the sound is attenuated in a frequency range of about 300 Hz or higher. In this way, in the sound reduction device 100 of the third embodiment, by connecting the first resonating section 21, the second resonating section 22, and the third resonating section 23 to form air chambers of different capacities (first air chamber A1, second air chamber A2, third air chamber A3), the frequency range in which sound is reduced can be broadened compared to the sound reduction devices 100 of the first and second embodiments.

[0033] As described above, the first to third types of sound reduction devices 100 have different frequency ranges for sound reduction, and therefore, the first to third types of sound reduction devices 100 can be used appropriately depending on the pitch of the voice of the user of the sound reduction device 100. For example, when a person with a relatively low voice (e.g., below 800 Hz) uses the sound reduction device 100, a sufficient sound reduction effect can be obtained by using the sound reduction device 100 of the third type. Alternatively, when a person with a high voice (e.g., above 800 Hz), such as a child, a small person, or a woman, uses the sound reduction device 100, a sufficient sound reduction effect can be obtained by using the sound reduction device 100 of the second type. In this case, the sound reduction device 100 used is smaller than the sound reduction device 100 of the third type, which improves wearability and appearance.

[0034] Furthermore, the sound reduction devices 100 of the first to third types can be used appropriately depending on the frequency range for which sound reduction is desired. For example, if it is desired to reduce only particularly harsh sounds (for example, 1.5 kHz or higher), a sufficient sound reduction effect for the particularly harsh sounds can be obtained by using the sound reduction device 100 of the first type. In this case, since the sound reduction device 100 is smaller than the sound reduction devices 100 of the second and third types, it is possible to improve the fit and appearance. Furthermore, if one is playing games in one's room and does not care about appearance and wants to increase the sound reduction effect, the sound reduction device 100 of the third type can be used to obtain a sufficient sound reduction effect. Furthermore, if one is working remotely in a cafe and speaking in a low voice, the sound reduction device 100 of the second type can be used to obtain a sufficient sound reduction effect.

[0035] [Variation 1] Next, a description will be given of Modification 1 of the present invention. In Modification 1, the same components as those in the above embodiment are given the same reference numerals, and the description thereof will be omitted.

[0036] 10, the sound reduction device 100 of the first modification includes a plurality of first resonators 21 as a resonance tube unit 20. The first resonator 21 located on the negative Y-axis side is referred to as first resonator 21A, and the first resonator 21 located on the positive Y-axis side is referred to as first resonator 21B. When the sound reduction device 100 of the first modification is worn by a user and the user speaks, the sound enters the inside of the first tube portion 211 of the first resonator 21A from the negative Y-axis side through the through hole 12. Then, a resonance sound corresponding to a wavelength according to the capacity of the first air chamber A1 is generated in the first air chamber A1 of the first resonator 21A. At a joint 212a (the end of the first neck 212 on the positive side of the Z-axis) between the first tubular portion 211 and the first neck 212 of the first resonator 21A, the sound (incident sound) incident on the first neck 212 from the first tubular portion 211 of the first resonator 21A and the resonance sound (emitted sound) generated in the first air chamber A1 of the first resonator 21A interfere with each other, and the frequency sound corresponding to the capacity of the first air chamber A1 is canceled out. As a result, the frequency sound corresponding to the capacity of the first air chamber A1 is attenuated and emitted from the outlet of the first tubular portion 211 of the first resonator 21A (the end of the first tubular portion 211 on the positive side of the Y-axis). Next, the sound with the frequency sound corresponding to the capacity of the first air chamber A1 attenuated is incident from the outlet of the first tubular portion 211 of the first resonator 21A into the inside of the first tubular portion 211 of the first resonator 21B. Similar to the first resonance part 21 of the first resonance part 21A, at the outlet of the first pipe part 211 of the first resonance part 21B, sound of a frequency corresponding to the capacity of the first air chamber A1 is further attenuated and emitted. In other words, in the sound-reduction device 100, by connecting first resonance parts 21 having air chambers of the same capacity, it is possible to more powerfully attenuate sound in the frequency range (resonant frequency) corresponding to the capacity of the first air chamber A1.

[0037] The sound reduction device 100 of Modification 1 may include a plurality of second resonance parts 22 as the resonance pipe unit 20. In this case, sound can be reduced more powerfully in the frequency range (resonance frequency) corresponding to the capacity of the second air chamber A2. The sound reduction device 100 of Modification 1 may include a plurality of third resonance parts 23 as the resonance pipe unit 20. In this case, sound can be reduced more powerfully in the frequency range (resonance frequency) corresponding to the capacity of the third air chamber A3.

[0038] [Variation 2] Next, a description will be given of Modification 2 of the present invention. In Modification 2, the same components as those in the above embodiment are given the same reference numerals, and the description thereof will be omitted.

[0039] As shown in FIGS. 11 and 12 , the sound reduction device 100 of the second modification includes a fourth resonance section 24 as a resonance tube unit 20. The fourth resonance section 24 includes a fourth tube section 241, a fourth neck section 242, a fifth neck section 243, a fourth resonance tube 244, and a fifth resonance tube 245. The fourth resonance tube 244 has a fourth air chamber A4 therein. The fifth resonance tube 245 has a fifth air chamber A5 therein, the fifth air chamber A5 having a larger capacity than the fourth air chamber A4. The fourth tube section 241 is a hollow tube with a semi-elliptical internal cross section and is located at the center of the fourth resonance section 24 in the X-axis direction. The fourth resonance tube 244 is located on the negative X-axis side of the fourth tube section 241, and the fifth resonance tube 245 is located on the positive X-axis side of the fourth tube section 241. One end 241a, which is the entrance of the fourth pipe section 241, and the through hole 12 of the protective section 10 overlap each other in the Z-axis direction and are adjacent to each other in the Y-axis direction. The fourth pipe section 241 extends linearly in the negative Z-axis direction from the one end 241a to the other end 241b, which is the exit. This allows communication between the internal space of the fourth pipe section 241 and the through hole 12 of the protective section 10. In other words, the outside of the sound reduction device 100 of Modification 2 and the inside of the protective section 10 are connected by the fourth pipe section 241 and the through hole 12. Furthermore, the exit (other end 241b) of the fourth pipe section 241 faces in the negative Z-axis direction. This allows sound emitted by a user wearing the sound reduction device 100 of Modification 2 to pass through the fourth pipe section 241 and be emitted in the negative Z-axis direction. This reduces sound traveling forward of the user (positive Y-axis direction). The fourth pipe portion 241 communicates with a fourth resonance pipe 244 via a fourth neck portion 242. The fourth pipe portion 241 communicates with a fifth resonance pipe 245 via a fifth neck portion 243.

[0040] 11 and 12 , the through hole 12, the fourth neck portion 242, and the fifth neck portion 243 are arranged at positions where they overlap with each other in the Z-axis direction, but this is not limited thereto. The fourth neck portion 242 and the fifth neck portion 243 may be arranged at positions where they do not overlap with the through hole 12 in the Z-axis direction. That is, the fourth neck portion 242 and the fifth neck portion 243 may branch off from the fourth pipe portion 241 on the negative Z-axis direction side of the through hole 12. Furthermore, the fourth neck portion 242 and the fifth neck portion 243 may be arranged at positions where they do not overlap with each other in the Z-axis direction. That is, the fourth neck portion 242 and the fifth neck portion 243 may branch off from the fourth pipe portion 241 at different positions in the Z-axis direction.

[0041] When the sound reduction device 100 of Modification 2 is worn by a user and the user speaks, the sound enters the fourth tube portion 241 from the negative Y-axis direction through the through-hole 12. A resonance sound corresponding to a wavelength corresponding to the volume of the fourth air chamber A4 is generated within the fourth air chamber A4. At the joint 242a between the fourth tube portion 241 and the fourth neck portion 242 (the end of the fourth neck portion 242 on the positive X-axis direction side), the sound (incident sound) entering the fourth neck portion 242 from the fourth tube portion 241 interferes with the resonance sound (emitted sound) generated within the fourth air chamber A4, canceling out the frequency sound corresponding to the volume of the fourth air chamber A4. In other words, the fourth neck portion 242 and the fourth resonance tube 244 form a Helmholtz resonator. A resonance sound corresponding to a wavelength corresponding to the volume of the fifth air chamber A5 is generated within the fifth air chamber A5. At a joint 243a (the end of the fifth neck 243 on the negative X-axis direction side) between the fourth tube 241 and the fifth neck 243, sound (incident sound) incident on the fifth neck 243 from the fourth tube 241 interferes with a resonance sound (emitted sound) generated in the fifth air chamber A5, canceling out a frequency sound corresponding to the capacity of the fifth air chamber A5. In other words, the fifth neck 243 and the fifth resonance tube 245 form a Helmholtz resonator. As a result, at the outlet (other end 241b) of the fourth tube 241, a frequency sound (resonant frequency) corresponding to the capacity of the fourth air chamber A4 and a frequency sound (resonant frequency) corresponding to the capacity of the fifth air chamber A5 are attenuated and emitted. In other words, in the sound reduction device 100 of Modification 2, the sound emitted by the user is emitted to the outside of the sound reduction device 100 with the frequency sound corresponding to the capacity of the fourth air chamber A4 and the frequency sound corresponding to the capacity of the fifth air chamber A5 attenuated.

[0042] As described above, the sound-reduction device 100 according to this embodiment includes the protective unit 10 having the through hole 12 and resonance units (first resonance unit 21, second resonance unit 22, third resonance unit 23, fourth resonance unit 24) that can be attached to the protective unit 10. The resonance units include pipe units (first pipe unit 211, second pipe unit 221, third pipe unit 231, fourth pipe unit 241) that have one end open to the outside air and the other end connected to the through hole 12, and resonators that have spaces that communicate with the internal spaces of the pipe units. The protective unit 10 is configured so that at least two or more types of resonance units with different resonator capacities can be interchangeably attached. Therefore, sound that enters the protective unit 10 can be reduced in a frequency range that corresponds to the capacity of the resonator, and the frequency range to be reduced can be adjusted by changing the resonance units.

[0043] In the sound reduction device 100 according to this embodiment, the protective part 10 has an opening 11 that is placed in a position that surrounds the user's mouth when the user wears the sound reduction device 100. Therefore, when the user wears the sound reduction device 100, the sound emitted by the user can be effectively reduced by the resonator.

[0044] In the sound reduction device 100 according to this embodiment, the resonator includes resonance tubes (first resonance tube 213, second resonance tube 223, third resonance tube 233, fourth resonance tube 244, fifth resonance tube 245) and neck portions (first neck portion 212, second neck portion 222, third neck portion 232, fourth neck portion 242, fifth neck portion 243) branching from the tube portions (first tube portion 211, second tube portion 221, third tube portion 231, fourth tube portion 241) and having spaces communicating with the internal spaces of the resonance tubes. The neck portions and the resonance tubes form a Helmholtz resonator. Therefore, sound incident inside the protective unit 10 can be effectively reduced by the Helmholtz resonator in a frequency range corresponding to the capacity of the resonance tube.

[0045] The sound reduction device 100 according to this embodiment includes multiple types of resonance parts (first resonance part 21, second resonance part 22, third resonance part 23) with different resonator capacities. Therefore, the frequency range in which sound is reduced can be broadened compared to when the sound reduction device 100 includes only one resonance part.

[0046] In the sound reduction device 100 according to this embodiment, the resonance portions (first resonance portion 21, second resonance portion 22) are provided with alignment means (marks M1, M2) for aligning the pipe portions (first pipe portion 211, second pipe portion 221, third pipe portion 231, fourth pipe portion 241) with the through hole 12. Therefore, the pipe portions and the through hole 12 can be easily positioned so as to overlap each other in the Z-axis direction.

[0047] In the sound-reduction device 100 according to this embodiment, the protective part 10 includes a microphone 13 therein. Therefore, the sound-reduction device 100 can be used when holding a remote conference in an office or at home, and can reduce the likelihood that the user's voice will be heard by people around them. This prevents people around them from learning the content of their conversation or causing discomfort to those around them.

[0048] The above-described embodiments are illustrative examples for the purpose of facilitating understanding of the invention, and the present invention is not limited to these embodiments. Various modifications and variations are possible without departing from the spirit and scope of the invention. For example, in the sound reduction device 100 of Modification 2, the fourth pipe portion 241 is arranged between the fourth resonance pipe 244 and the fifth resonance pipe 245 in the X-axis direction, but this is not limiting. The fourth resonance pipe 244 and the fifth resonance pipe 245 may also be arranged side by side in the Z-axis direction. [Explanation of symbols]

[0049] 100... sound reduction device, 10... protective part, 11... opening, 12... through hole, 13... microphone, 21... first resonance part, 211... first tube part, 212... first neck part, 213... first resonance tube, 22... second resonance part, 221... second tube part, 222... second neck part, 223... second resonance tube, 23... third resonance part, 231... third tube part, 232... third neck part, 233... third resonance tube, 24... fourth resonance part, 241... fourth tube part, 242... fourth neck part, 243... fifth neck part, 244... fourth resonance tube, 245... fifth resonance tube, M1, M2... marks (alignment means)

Claims

1. a protective portion having a through hole; a resonance part that can be attached to the protection part; Equipped with the resonance unit includes a tube portion having one end open to the outside air and the other end connected to the through hole, and a resonator having a space communicating with an internal space of the tube portion, The protection section is a sound-reducing device configured so that at least two or more types of resonating sections having different capacities of the resonators can be replaced with each other.

2. The sound reduction device according to claim 1 , wherein the protective portion has an opening that is disposed in a position that surrounds the user's mouth when the user wears the sound reduction device.

3. the resonator includes a resonance tube and a neck portion branching from the tube portion and having a space communicating with an internal space of the resonance tube; 2. The sound-reducing device according to claim 1, wherein the neck portion and the resonator tube form a Helmholtz resonator.

4. The sound-reducing device according to claim 1 , comprising a plurality of types of resonating portions each having a different capacity of the resonator.

5. 2. The sound-reducing device according to claim 1, wherein the resonating portion includes alignment means for aligning the tubular portion with the through-hole.

6. 2. The sound-reducing device according to claim 1, wherein the protective portion includes a microphone therein.

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