Vibrating structure, passive radiator, and sound absorbing structure

Abstract

To provide a vibration structure capable of suppressing stress concentration in an elastic portion that deforms in accordance with vibration of a vibration mass.SOLUTION: A vibration structure 1 includes a vibration mass 10, a support portion 20, and an elastic portion 30. The vibration mass 10 is a plate-shaped portion. The support portion 20 is a portion having a space 21 capable of accommodating the vibration mass 10. The elastic portion 30 is an elastically deformable portion that connects the vibration mass 10 to the support portion 20. The elastic portion 30 extends along an outer periphery 13 of the vibration mass 10, and supports the vibration mass 10 such that the vibration mass 10 can vibrate in the direction in which the front surface 11 and the back surface 12 of the vibration mass 10 face relative to the support portion 20. The vibration mass 10 has a plurality of corners 14 on the outer periphery 13. The height H of the plurality of corners 31 of the elastic portion 30 located at the plurality of corners 14 of the vibration mass 10 is higher than the height of the sides 32, 33 of the elastic portion 30. The height H is the distance in the direction in which the front surface 11 and the back surface 12 face.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a vibration structure, a passive radiator, and a sound absorption structure, and more particularly to a vibration structure, a passive radiator, and a sound absorption structure having a vibration mass.

Background Art

[0002] Conventionally, vibration structures having a vibration mass have been used in various devices. For example, a vibration structure having a plate-shaped vibration mass has conventionally been used in a passive radiator and a sound absorption structure.

[0003] In the vibration structure having a plate-shaped vibration mass as described above, the vibration mass is supported by a support portion fixed to a housing or the like via an elastic portion, and the vibration mass resonates at a specific frequency. The elastic portion connects the outer peripheral edge of the vibration mass and the inner peripheral edge of a housing portion formed in the support portion for accommodating the vibration mass, and extends annularly along the outer peripheral edge of the vibration mass. The vibration mass has a shape such as an ellipse, a rectangle, or a circle. Further, the shape of the elastic portion in a cross section along the vibration direction of the vibration mass is an arc shape (see, for example, Patent Document 1).

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] In the vibration structure as described above, the elastic portion deforms in response to the vibration of the vibration mass. Depending on the shape of the vibration mass, stress concentration occurs in the elastic portion, leading to damage to the elastic portion. For example, in a vibration structure having a rectangular vibration mass, stress concentration occurs in a portion of the elastic portion corresponding to the corner of the vibration mass. When stress concentration occurs in the elastic portion, damage to the stress concentration portion is a concern.

[0006] Therefore, for a conventional vibration structure, a configuration capable of preventing the occurrence of stress concentration in an elastic portion that deforms as the vibration mass vibrates is required.

[0007] The present invention has been made in view of the above problems, and an object thereof is to provide a vibration structure, a passive radiator, and a sound absorption structure capable of suppressing stress concentration in an elastic portion that deforms as the vibration mass vibrates.

Means for Solving the Problems

[0008] In order to achieve the above object, a vibration structure according to the present invention includes a vibration mass that is a plate-shaped portion having a first surface and a second surface that are a pair of opposing surfaces, a support portion that is a portion having a space capable of accommodating the vibration mass, and an elastic portion that is an elastically deformable portion connecting the vibration mass to the support portion. The elastic portion extends along the outer peripheral edge of the vibration mass, supports the vibration mass so as to be vibratable in a direction facing the first surface and the second surface of the vibration mass with respect to the support portion, the vibration mass has a plurality of corner portions at the outer peripheral edge, and the heights of a plurality of portions of the elastic portion respectively located at the plurality of corner portions of the vibration mass are higher than the heights of other portions of the elastic portion. The height is the distance in the direction facing the surface.

[0009] In the vibration structure according to one aspect of the present invention, the shape of a cross section orthogonal to the extending direction of the elastic portion is an arc shape protruding in the direction facing the first surface.

[0010] In the vibration structure according to one aspect of the present invention, the other portions of the elastic portion gradually become higher toward the plurality of portions of the elastic portion.

[0011] In the vibration structure according to one aspect of the present invention, the heights of some of the other portions of the elastic portion are constant.

[0012] In the vibration structure according to one aspect of the present invention, the plurality of portions of the elastic portion have the same shape as each other.

[0013] In the vibration structure according to one aspect of the present invention, the shapes of the first surface and the second surface of the vibration mass are rectangular, the vibration mass has four corners, and the elastic portion has four of the portions.

[0014] In order to achieve the above object, the passive radiator according to the present invention includes the vibration structure according to the present invention.

[0015] In the passive radiator according to one aspect of the present invention, the vibration mass includes a first plate portion that is a plate-like portion having one of the first surface and the second surface, and a second plate portion that is a plate-like portion having the other of the first surface and the second surface, the first plate portion and the second plate portion are fixed to each other, and the first plate portion, the elastic portion, and the support portion are integrated.

[0016] In order to achieve the above object, the sound absorption structure according to the present invention includes the vibration structure according to the present invention.

[0017] In the sound absorption structure according to one aspect of the present invention, the vibration mass, the elastic portion, and the support portion are integrated.

Effects of the Invention

[0018] According to the present invention, it is possible to suppress the occurrence of stress concentration in the elastic portion that deforms as the vibration mass vibrates.

Brief Description of the Drawings

[0019]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Mode for Carrying Out the Invention

[0020] Hereinafter, embodiments of the present invention will be described with reference to the drawings.

[0021] FIG. 1 is a perspective view showing a schematic configuration of a vibration structure 1 according to a first embodiment of the present invention, FIG. 2 is a cross-sectional view showing a cross-section along line A-A in FIG. 1, and FIG. 3 is a cross-sectional view showing a cross-section along line B-B in FIG. 1. As shown in FIGS. 1 to 3, the vibration structure 1 includes a vibration mass 10, a support portion 20, and an elastic portion 30. The vibration mass 10 is a plate-like portion having a front surface 11 as a first surface and a back surface 12 as a second surface, which are a pair of opposing surfaces. The support portion 20 is a portion having a space 21 capable of accommodating the vibration mass 10. The elastic portion 30 is an elastically deformable portion that connects the vibration mass 10 to the support portion 20. The elastic portion 30 extends along the outer peripheral edge 13 of the vibration mass 10 and supports the vibration mass 10 so as to be vibratable in the direction facing the front surface 11 and the back surface 12 of the vibration mass 10 with respect to the support portion 20. The vibration mass 10 has a plurality of corner portions 14 on the outer peripheral edge 13. The height H of the plurality of portions 31 of the elastic portion 30 respectively located at the plurality of corner portions 14 of the vibration mass 10 is higher than the height of the other portions 32, 33 of the elastic portion 30. The height H is the distance in the direction facing the front surface 11 and the back surface 12. Hereinafter, the configuration of the vibration structure 1 will be specifically described.

[0022] As shown in FIG. 1 below, for the sake of convenience of explanation, the direction facing the front surface 11, which is the first surface of the vibration mass 10, is defined as the front side, and the direction facing the back surface 12, which is the second surface of the vibration mass 10, is defined as the back side. Note that the front side and the back side do not limit the posture of the vibration structure 1 in the use state. Also, in the drawings, not all of the plurality of components are labeled, and the labels of some of the plurality of components may be omitted.

[0023] As shown in FIGS. 1 to 3, the vibration mass 10 has a rectangular or substantially rectangular outer peripheral edge 13. Note that the outer peripheral edge 13 is an annular surface facing the outer peripheral side. Therefore, the outer peripheral edge 13 of the vibration mass 10 has four corner portions 14 and also has four side portions 15. As shown in FIGS. 1 and 2 as an example, the shape of the outer peripheral edge 13 of the vibration mass 10 as viewed from the front side and the back side is rectangular or substantially rectangular, and as the sides 15, it has a pair of sides 15a and a pair of sides 15b. Also, the corner portions 14 as viewed from the front side and the back side draw curves such as arcs or arcs. Note that the shape of the corner portions 14 is not limited to this. For example, the corner portions 14 as viewed from the front side and the back side may be points. The vibration mass 10 is a plate-like member as described above. For example, the width between the front surface 11 and the back surface 12 is constant or substantially constant.

[0024] As shown in FIGS. 1 to 3, the support portion 20 is, for example, a plate-like member and has a space 21 capable of accommodating the vibration mass 10 inside. That is, the support portion 20 has an inner peripheral edge 22 which is an annular edge facing the inner peripheral side, and the space surrounded by the inner peripheral edge 22 is the space 21. The space 21 of the support portion 20 is larger than the vibration mass 10. When the vibration mass 10 is accommodated in the space 21 of the support portion 20, an annular gap is formed between the outer peripheral edge 13 of the vibration mass 10 and the inner peripheral edge 22 of the support portion 20. The inner peripheral edge 22 of the support portion 20 has a shape similar to or substantially similar to the outer peripheral edge 13 of the vibration mass 10, for example. Thereby, the annular gap between the outer peripheral edge 13 of the vibration mass 10 accommodated in the space 21 of the support portion 20 and the inner peripheral edge 22 of the support portion 20 has a constant or substantially constant width over the entire circumference.

[0025] The elastic part 30 extends into the annular gap between the outer peripheral edge 13 of the vibration mass 10 accommodated in the space 21 of the support part 20 and the inner peripheral edge 22 of the support part 20, and connects the vibration mass 10 to the support part 20 such that the vibration mass 10 can vibrate on the front side and the back side. As shown in FIGS. 2 and 3, the cross-sectional shape of the elastic part 30 is arc-shaped, for example, circular arc-shaped or substantially circular arc-shaped.

[0026] The height H of the four corner parts 31 of the elastic part 30 respectively located at the corner parts 14 of the vibration mass 10 is higher than the height h of the other parts of the elastic part 30. As shown in FIG. 1, the corner parts 31 of the elastic part 30 are parts that extend along the corner parts 14 of the vibration mass 10. Further, the other parts 32, 33 of the elastic part 30 are side parts 32, 33 that are parts of the elastic part 30 extending along the side parts 15a, 15b of the vibration mass 10.

[0027] As shown in FIG. 1, the height H of the corner parts 31 of the elastic part 30 is, for example, constant or substantially constant throughout. The side part 32 of the elastic part 30 has, for example, a first part 32a that is a part where the height h is constant or substantially constant at the center or substantially the center, and a second part 32b that is the parts at both ends of the side part 32. The second part 32b is connected to both ends of the corner part 31 respectively. The height h2 of the second part 32b gradually increases, for example, from the end on the first part 32a side toward the end on the corner part 31 side. Note that the height h2 of the second part 32b does not necessarily have to gradually increase from the end on the first part 32a side toward the end on the corner part 31 side, and may be constant in part, for example. The corner part 31 and the second part 32b of the side part 32 are smoothly connected without a step, and similarly, in the side part 32, the first part 32a and the second part 32b are smoothly connected without a step. The height H of the corner part 31 is, for example, twice or substantially twice the height of the first part 32a of the side part 32. Note that the side part 32 does not necessarily have to have the first part 32a with a constant height.

[0028] As shown in FIG. 1, the side portion 33 of the elastic portion 30 has the same form as the side portion 32. For example, at the center or approximately the center, there is a first portion 33a which is a portion where the height h is constant or approximately constant and has a height h3, and a second portion 33b which is a portion at both ends of the side portion 33. The second portion 33b is connected to both ends of the corner portion 31 respectively. The height h4 of the second portion 33b gradually increases, for example, from the end on the first portion 33a side toward the end on the corner portion 31 side. Note that the height h4 of the second portion 33b does not necessarily have to gradually increase from the end on the first portion 33a side toward the end on the corner portion 31 side, and may be constant in some parts, for example. The corner portion 31 and the second portion 33b of the side portion 33 are smoothly connected without a step. Similarly, in the side portion 33, the first portion 33a and the second portion 33b are smoothly connected without a step. The height H of the corner portion 31 is, for example, twice or approximately twice the height of the first portion 33a of the side portion 33. Note that the side portion 33 does not necessarily have to have the first portion 33a with a constant height.

[0029] FIG. 3 shows a cross-section of the corner portion 31. The cross-sectional shape of the corner portion 31 is the same or approximately the same throughout the entire corner portion 31. For example, as shown in FIG. 3, it has a U-shaped groove-like shape that curves so as to protrude on the front side. The cross-sectional shape of the corner portion 31 has, for example, a top portion 31a and wall portions 31b, 31c. The top portion 31a is the front-side portion of the corner portion 31, and the wall portions 31b, 31c are the back-side portions of the corner portion 31. The wall portions 31b, 31c respectively extend from the back-side ends of the top portion 31a and are connected to the outer peripheral edge 13 of the vibration mass 10 and the inner peripheral edge 22 of the support portion 20. The cross-sectional shape of the top portion 31a is, for example, an arc shape or approximately an arc shape. Specifically, the cross-sectional shape of the top portion 31a is, for example, a semi-arc shape or approximately a semi-arc shape. The wall portion 31b is, for example, a curved plate shape, and the wall portion 31c is, for example, a flat plate shape.

[0030] FIG. 2 shows a cross section of the first portion 32a of the side portion 32. As shown in FIG. 2, the cross-sectional shape of the first portion 32a of the side portion 32 is, for example, arc-shaped or substantially arc-shaped. Specifically, the cross-sectional shape of the first portion 32a is, for example, semi-arc-shaped or substantially semi-arc-shaped. Further, the cross-sectional shape of the first portion 32a of the side portion 32 is, for example, the same as or substantially the same as the shape of the top portion 31a of the corner portion 31. The cross-sectional shape of the second portion 32b of the side portion 32 gradually changes from the end on the first portion 32a side toward the end on the corner portion 31 side, and is shaped so as to smoothly connect to the first portion 32a and the corner portion 31 without a step. As shown in FIG. 1, for example, the second portion 32b of the side portion 32 has, on the front side, a top portion having the same or substantially the same shape as the top portion 31a of the corner portion 31, and two wall portions extending from both ends of the top portion. The height of the two wall portions gradually increases from the first portion 32a side toward the corner portion 31 side.

[0031] The cross-sectional shape of the first portion 33a of the side portion 33 is, for example, arc-shaped or substantially arc-shaped. Specifically, the cross-sectional shape of the first portion 33a is, for example, semi-arc-shaped or substantially semi-arc-shaped. Further, the cross-sectional shape of the first portion 33a of the side portion 33 is, for example, the same as or substantially the same as the cross-sectional shape of the first portion 32a of the side portion 32. Further, the cross-sectional shape of the first portion 33a of the side portion 33 is, for example, the same as or substantially the same as the shape of the top portion 31a of the corner portion 31. The cross-sectional shape of the second portion 33b of the side portion 33 gradually changes from the end on the first portion 33a side toward the end on the corner portion 31 side, and is shaped so as to smoothly connect to the first portion 33a and the corner portion 31 without a step. The second portion 33b of the side portion 33 has, for example, on the front side, a top portion having the same or substantially the same shape as the top portion 31a of the corner portion 31, and two wall portions extending from both ends of the top portion. The height of the two wall portions gradually increases from the first portion 33a side toward the corner portion 31 side.

[0032] The thickness (thickness t) of the elastic portion 30 is, for example, constant or substantially constant over the entire elastic portion 30. That is, the thickness t of the corner portion 31, the side portion 32, and the side portion 33 is the same or substantially the same. Note that the thickness t of the elastic portion 30 is the distance between the surface facing the front side of the elastic portion 30 and the surface facing the back side, as shown in FIGS. 2 and 3.

[0033] The vibration mass 10, the elastic part 30, and the support part 20 are integrated. That is, the vibration structure 1 is integrally formed from a specific material, and the vibration mass 10, the elastic part 30, and the support part 20 are each part of the vibration structure 1 and are integrally connected. The material of the vibration structure 1 is, for example, metal or resin. The resin of the vibration structure 1 is, for example, a synthetic resin with excellent sound absorption properties such as polypropylene or nylon. Also, the material of the vibration structure 1 is, for example, an elastic material. The elastic material of the vibration structure 1 is, for example, an elastomer, and specifically, for example, rubber. Examples of the rubber as the elastic material of the vibration structure 1 include silicone rubber, urethane rubber, ethylene propylene rubber, butyl rubber, ethylene propylene diene rubber, nitrile rubber, etc. Note that the elastic material of the vibration structure 1 is not limited to rubber.

[0034] Next, the operation of the vibration structure 1 having the above-described configuration will be described.

[0035] Since the vibration mass 10 is supported by the support part 20 via the elastic part 30, the vibration mass 10 is capable of vibrating with respect to the support part 20. Specifically, the vibration mass 10 is capable of vibrating on the front side and the back side. The vibration mass 10 resonates at a specific frequency and acts as an inertial mass at that time. In this way, the vibration structure 1 constitutes a film vibration system having the vibration mass 10 that vibrates the film. Due to the vibration of the vibration mass 10, the vibration structure 1 can generate sounds in a predetermined frequency band and can also absorb sounds in a predetermined frequency band. The resonance frequency of the vibration mass 10 can be set to an arbitrary frequency using, for example, the size and specific gravity of the vibration mass 10, the elastic modulus or flexibility of the elastic part 30, etc. as parameters.

[0036] Due to the vibration of the vibration mass 10, the elastic part 30 deforms, and stress is generated in the elastic part 30. If the height of the corner part 31 of the elastic part 30 is the same as the height of the side parts 32, 33 of the elastic part 30, and the cross-sectional shape of the corner part 31 is the same as the cross-sectional shape of the side parts 32, 33, stress concentration may occur at the corner part 31, leading to premature breakage of the elastic part 30. Also, the occurrence of stress concentration indicates a high elastic modulus or low flexibility, increasing the spring constant of the elastic part. In contrast, in the vibration structure 1, the height H of the corner part 31 of the elastic part 30 is higher than the height h of the side parts 32, 33 of the elastic part 30, and the elastic modulus or flexibility of the corner part 31 is increased to be higher than or equivalent to that of the side parts 32, 33, making the corner part 31 softer than or equivalent to the side parts 32, 33. Therefore, the occurrence of stress concentration at the corner part 31 is suppressed. As a result, the elastic part 30 is less likely to break, and the vibration structure 1 is less likely to break. Also, the low-frequency vibration of the vibration mass 10 can be achieved.

[0037] Thus, according to the vibration structure 1 according to the first embodiment of the present invention, stress concentration in the elastic part 30 that deforms with the vibration of the vibration mass 10 can be suppressed.

[0038] Next, the vibration structure 2 according to the second embodiment of the present invention will be described. FIG. 4 is a cross-sectional perspective view showing the schematic configuration of the vibration structure 2 according to the second embodiment of the present invention. As shown in FIG. 4, the vibration structure 2 has a different vibration mass configuration compared to the vibration structure 1. Hereinafter, for the configuration of the vibration structure 2, the description of the same configuration or the configuration having the same function as the above-described vibration structure 1 will be omitted, and the different configurations will be described.

[0039] As shown in FIG. 4, the vibration mass 16 of the vibration structure 2 is a plate-like portion having a pair of opposing surfaces, i.e., the front surface 16a as the first surface and the rear surface 16b as the second surface. Further, the vibration mass 16 has a first plate portion 17 which is a plate-like portion having one of the front surface 16a and the rear surface 16b, and a second plate portion 18 which is a plate-like portion having the other of the front surface 16a and the rear surface 16b. The first plate portion 17 and the second plate portion 18 are fixed to each other. Also, the first plate portion 17, the elastic portion 30, and the support portion 20 are integrated. The first plate portion 17 is the vibration mass 10 of the above-described vibration structure 1. That is, the first plate portion 17, the elastic portion 30, and the support portion 20 form the vibration structure 1. As shown in FIG. 4, the first plate portion 17 has, for example, the front surface 16a of the vibration mass 16, and the second plate portion 18 has, for example, the rear surface 16b of the vibration mass 16. That is, the front surface 11 of the first plate portion 17 is the front surface 16a of the vibration mass 16.

[0040] As shown in FIG. 4, the second plate portion 18 has the same shape as the first plate portion 17 and has a front surface 18a having the same or substantially the same shape as the rear surface 12 of the first plate portion 17. Further, the second plate portion 18 has a rear surface 18b facing the front surface 18a. This rear surface 18b is the rear surface 16b of the vibration mass 16. The front surface 18a of the second plate portion 18 faces the rear surface 12 of the first plate portion 18, and the front surface 18a of the second plate portion 18 and the rear surface 12 of the first plate portion 17 are fixed to each other, and the first plate portion 17 and the second plate portion 18 are fixed to each other. The rear surface 12 of the first plate portion 17 and the front surface 18a of the second plate portion 18 are fixed to each other, for example, by adhesion.

[0041] The vibration structure 2 also operates in the same manner as the above-described vibration structure 1 and exhibits the same effects.

[0042] In the vibration mass 16 of the vibration structure 2, although the first plate portion 17 is located on the front side and the second plate portion 18 is located on the back side, the first plate portion 17 may be located on the back side and the second plate portion 18 may be located on the front side. In this case, the front surface 18a of the second plate portion 18 becomes the front surface 16a of the vibration mass 16, and the back surface 12 of the first plate portion 17 becomes the back surface 16b of the vibration mass 16. Further, the back surface 18b of the second plate portion 18 faces the front surface 11 of the first plate portion 17, and the back surface 18b of the second plate portion 18 and the front surface 11 of the first plate portion 17 are fixed to each other, so that the first plate portion 17 and the second plate portion 18 are fixed to each other.

[0043] Next, a passive radiator according to an embodiment of the present invention including the vibration structure 1 or the vibration structure 2 will be described.

[0044] The vibration structure 1 or the vibration structure 2 can be used as a passive radiator. For example, as shown in FIG. 5, by attaching the vibration structure 2 to a speaker housing 40 (not shown), the vibration structure 2 becomes the passive radiator 2. In this case, the support portion 20 may be fixed to the housing 50, or a part of the housing 50 may form the support portion 20. Similarly, by attaching the vibration structure 1 to a speaker housing 50 (not shown), the vibration structure 1 becomes the passive radiator 1.

[0045] When a speaker (not shown) is vibrated, sound is radiated from the front of the speaker, and at the same time, a sound wave (sound pressure) with an inverted phase is radiated behind the speaker. Due to the pressure fluctuation of the sound pressure behind the speaker, the vibration mass 16 of the passive radiator 2 is vibrated to amplify and reinforce the sound. The passive radiator 1 using the vibration structure 1 also acts in the same manner.

[0046] For example, by appropriately setting the weight of the vibration mass 16 of the vibration structure 2 as the passive radiator 2, the spring constant of the elastic portion 30, and the spring constant of the air spring formed in the internal space of the housing 50, it is possible to amplify and reinforce low-frequency sounds that are difficult to radiate a large volume with a single speaker. The passive radiator 1 using the vibration structure 1 also acts in the same manner.

[0047] The vibration mass 16 of the vibration structure 2 is rectangular, and has higher space efficiency than vibration masses in the shape of a circle or an ellipse. For example, in the same rectangular space, the vibration mass can be made larger. Therefore, it can be suitably used for an elongated speaker system such as a sound bar. The same applies to the passive radiator 1 using the vibration structure 1.

[0048] As described above, the vibration structures 1 and 2 according to the embodiments of the present invention can provide a passive radiator with good space efficiency and high damage resistance.

[0049] Next, an acoustic structure 3 according to an embodiment of the present invention including the vibration structure 1 will be described. FIG. 6 is a perspective view showing a part of the acoustic structure 3, and FIG. 7 is a cross-sectional view showing a cross-section taken along line C-C of FIG. 6.

[0050] As shown in FIG. 6, the acoustic structure 3 has a resonator 40. Although only one resonator 40 is shown in FIG. 6, the acoustic structure 3 has a predetermined number of resonators 40, and the plurality of resonators 40 are arranged in a predetermined form.

[0051] As shown in FIGS. 6 and 7, the acoustic structure 3 has a base portion 41 which is a plate-shaped member, and a box portion 42 which is a box-shaped member fixed on the base portion 41. The shape of the box portion 42 in side view is trapezoidal, the box portion 42 has an opening 43 on the back side, and the back side is open. Further, the box portion 42 has a rectangular plate frame-shaped top surface portion 44 on the front side, and the vibration structure 1 is provided on the top surface portion 44. The front surface 11 of the vibration mass 10 of the vibration structure 1 faces the front side. The support portion 20 of the vibration structure 1 is formed by the top surface portion 44. Note that the top surface portion 44 and the support portion 20 may be formed as separate bodies, and in this case, the support portion 20 is fixed to the top surface portion 44. A connecting portion 45 extends from an end portion on the back side of the box portion 42, and the plurality of box portions 42 are connected to each other via the connecting portion 45. The connecting portion 45 is a plate-shaped member with the opening 43 open, and has a surface 45a facing the back side. The surface 45a extends along a plane.

[0052] As shown in FIG. 7, the box portion 42 forms a space having the same shape or substantially the same shape as the box portion 42 inside. The connecting portion 45 is fixed on the base portion 41, the back side of the box portion 42 is fixed on the base portion 41, the opening 43 of the box portion 42 is closed by the base portion 41, and the base portion 41 and the box portion 42 form a cavity 46 closed inside the box portion 42, and the resonator 40 is formed. Note that the plurality of resonators 40 do not all have to be the same size. That is, the volumes and heights of the cavities 46 of the plurality of resonators 40 do not all have to be the same.

[0053] The sound absorption structure 3 has the above-described configuration. When the vibration mass 10 of the vibration structure 1 receives sound pressure from the front side, the film vibrates. Further, the air in the cavity 46 functions as an air spring. For this reason, each resonator 40 absorbs sound in a frequency band corresponding to the resonator 40 from the sound incident from the sound source by the film vibration of the vibration mass 10 and the air spring in the cavity 46.

[0054] When the shape seen from the front side is rectangular like the box portion 42, many box portions 42 can be densely arranged on the base portion 41, and many resonators 40 can be densely arranged. Further, the vibration mass 10 that vibrates in a film shape is rectangular, and the area of the vibration mass 10 can be increased in the box portion 42, and the area of the top surface portion 44 that does not have a sound absorption function can be reduced. For this reason, the vibration structure 1 can increase the area of the vibration mass 10 having a sound absorption function by film vibration in the resonator 40, and can enhance the sound absorption effect of the resonator 40. Further, the range in which the area of the vibration mass 10 in the resonator 40 can be set can be widened, and the degree of freedom in setting the frequency band in which the resonator 40 absorbs sound can be increased. Further, the degree of freedom in the shape of the resonator 40 can be increased.

[0055] Also, as described above, in the vibration structure 1, the height H of the corner portion 31 of the elastic portion 30 is higher than the height h of the side portions 32 and 33 of the elastic portion 30, the flexibility of the corner portion 31 is enhanced, and the corner portion 31 is softened. Therefore, the occurrence of stress concentration at the corner portion 31 is suppressed. As a result, the elastic portion 30 is less likely to be damaged, and the vibration structure 1 is less likely to be damaged. For this reason, while suppressing damage, the elastic portion 30 can make the shape of the vibration mass 10 rectangular to enhance the sound absorption effect.

[0056] Also, as described above, the flexibility of the corner portion 31 of the elastic portion 30 is enhanced, and a decrease in the spring constant of the elastic portion 30 is achieved. Therefore, for example, when aiming to absorb sound in the low frequency band, it is not necessary to increase the size of the box portion 42. If the spring constant of the elastic portion 30 is high, the membrane vibration of the vibration mass 10 becomes high-frequency vibration. In this case, for example, when the sound absorption target of the resonator 10 is sound in the low frequency range below 1 kHz, it is necessary to increase the size of the box portion 42 to reduce the spring constant of the resonator 40. In this case, the sound absorption structure 3 becomes larger, and if a large sound absorption structure 3 is arranged in a limited space such as a narrow office, it gives a sense of oppression to the users of the space. On the other hand, as described above, the sound absorption structure 3 can suppress an increase in size. Therefore, for example, even if the sound absorption structure 3 is installed in a limited space such as a narrow office, it is possible to suppress giving a sense of oppression to the users of the space.

[0057] Note that the vibration structure 2 can also be used for the sound absorption structure 3 in the same manner as the vibration structure 1. Further, the vibration structures 1 and 2 according to the embodiment of the present invention can also be applied to rectangular speakers.

[0058] As described above, the present invention has been described through the above embodiments, but the technical scope of the present invention is not limited to the scope described in the above embodiments. It is obvious to those skilled in the art that various changes or improvements can be made to the above embodiments. It is clear from the description of the claims that forms with such changes or improvements can also be included in the technical scope of the present invention.

[0059] The embodiments described above are for facilitating the understanding of the present invention and are not for limiting and interpreting the present invention. Also, the above-described embodiments do not limit the objects to which the present invention is applied, and the present invention can include any object as its application target. Each component included in the above embodiments, as well as its arrangement, material, conditions, shape, size, etc. are not limited to those exemplified, and can be changed as appropriate. For example, the present invention includes differences that occur in the implementation such as manufacturing tolerances. Also, within a range where there is no technical contradiction, the components shown in different embodiments can be partially replaced or combined with each other. Further, each configuration can be selectively combined as appropriate so as to achieve at least part of the above-described problems and effects.

Explanation of Reference Numerals

[0060] 1, 2 Vibration structure (passive radiator), 3 Sound absorption structure, 10, 16 Vibration mass, 11, 16a Front surface, 12, 16b Rear surface, 13 Outer peripheral edge, 14 Corner, 15, 15a, 15b Side portion, 17 First plate portion, 18 Second plate portion, 18a Front surface, 18b Rear surface, 20 Support portion, 21 Space, 22 Inner peripheral edge, 30 Elastic portion, 31 Corner (portion), 31a Top portion, 31b, 31c Wall portion, 32, 33 Side portion, 32a, 33a First portion, 32b, 33b Second portion, 40 Resonator, 41 Base portion, 42 Box portion, 43 Opening, 44 Top surface portion, 45 Connection portion, 45a Surface, 46 Cavity, 50 Housing, H, h, h1, h2, h3, h4 Height, t Thickness

Claims

1. A vibration mass which is a plate-like part having a first surface and a second surface which are a pair of facing surfaces; A support part which is a part having a space capable of accommodating the vibration mass; An elastic part which is an elastically deformable part connecting the vibration mass to the support part, The elastic part extends along the outer peripheral edge of the vibration mass, and supports the vibration mass so as to be vibrationally movable in the direction in which the first surface and the second surface of the vibration mass face the support part, The vibration mass has a plurality of corners at the outer peripheral edge, The heights of a plurality of parts of the elastic part respectively located at the plurality of corners of the vibration mass are higher than the heights of other parts of the elastic part, The height is the distance in the direction in which the surface faces, A vibration structure.

2. The shape of a cross-section orthogonal to the extending direction of the elastic part is an arcuate shape protruding in the direction in which the first surface faces, The vibration structure according to Claim 1.

3. The other parts of the elastic part gradually become higher toward the plurality of parts of the elastic part, The vibration structure according to Claim 1.

4. The height of a part of the other parts of the elastic part is constant, The vibration structure according to Claim 3.

5. The plurality of parts of the elastic part have the same shape as each other, The vibration structure according to Claim 1.

6. The shapes of the first surface and the second surface of the vibration mass are rectangular, The vibration mass has four of the corners, The elastic part has four of the parts, The vibration structure according to Claim 1.

7. Comprising the vibration structure according to Claim 1, A passive radiator.

8. The vibration mass has a first plate part which is a plate-like part having one of the first surface and the second surface, and a second plate part which is a plate-like part having the other of the first surface and the second surface, The first plate part and the second plate part are fixed to each other, The first plate part, the elastic part, and the support part are integrated, The passive radiator according to Claim 7.

9. Comprising the vibration structure according to Claim 1, A sound absorption structure.

10. The vibration mass, the elastic part, and the support part are integrated, The sound absorption structure according to Claim 9.

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