Sound insulation portion

Abstract

To provide a sound insulation portion that can adjust a resonance frequency while suppressing size increase.SOLUTION: A sound insulation portion comprises: a plate-shaped sound insulation board 20 that forms an outer shell; and a hollow tubular resonance portion 30 that is formed inside the sound insulation board and has a sound insulation opening 41 at one end that communicates with the outside of the sound insulation board. The resonance portion forms a resonance space S in communication with the sound insulation opening, and has a bent portion 50 that is formed by bending.SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] The present disclosure relates to a sound insulation. [Background technology]

[0002] Conventionally, there is known a sound insulation structure having a plurality of resonating parts provided on a sound insulation sheet member provided on a support body in contact therewith (see, for example, Patent Document 1). The plurality of resonating parts are composed of a composite structure including a base part formed in a cylindrical shape extending in the axial direction, and a weight part embedded inside the tip side of the base part and having a larger mass than the base part. As a result, the resonating part functions as a resonator having a resonance frequency determined by the mass of the weight part acting as a weight and the spring constant of the base part acting as a spring.

[0003] When sound waves are incident on the support, resonance occurs in the resonating portion, thereby reducing the amplitude of the incident sound waves having frequencies near the resonant frequency of the resonating portion, thereby achieving sound insulation performance. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent No. 6610684 Summary of the Invention [Problem to be solved by the invention]

[0005] Incidentally, in a sound-insulating portion such as the sound-insulating structure described in Patent Document 1, it is necessary to adjust the resonance frequency at which the resonating portion resonates in accordance with the frequency of the sound waves that exhibit sound-insulating performance. For example, when lowering the frequency of the sound waves that exhibit sound-insulating performance, it is necessary to reduce the resonance frequency at which the resonating portion resonates, and when raising the frequency of the sound waves that exhibit sound-insulating performance, it is necessary to increase the resonance frequency at which the resonating portion resonates.

[0006] However, in a structure in which a resonating part composed of a base and a weight part embedded inside the base is resonated, such as the soundproofing structure described in Patent Document 1, it is necessary to increase the axial size of the cylindrical base in order to reduce the resonance frequency at which the resonating part resonates. However, increasing the axial size of the base undesirably increases the size of the soundproofing structure.

[0007] An object of the present disclosure is to provide a sound-proofing section that is capable of adjusting the frequency of sound to be reduced while suppressing an increase in size. [Means for solving the problem]

[0008] According to one aspect of the disclosure, The soundproofing section is A plate-shaped sound-proofing plate material (20) forming an outer shell; a hollow tubular resonator (30) formed inside the sound-proofing board and having a sound-proofing opening (41) at one end thereof communicating with the outside of the sound-proofing board; The resonator portion forms a resonator space (S) that communicates with the sound-insulating opening, and has bent portions (50, 50a, 50b, 55, 56) that are formed by bending.

[0009] With a soundproofing section configured in this manner, when sound is incident on the resonance space of the resonance section, Helmholtz resonance is generated in the resonance section, causing the resonance section to resonate and reducing the sound incident on the soundproofing section.

[0010] In addition, since the larger the volume of the resonance space, the lower the resonance frequency when the resonance part resonates due to Helmholtz resonance can be achieved. In a configuration in which the resonance part forming the resonance space has a bent part, the volume of the resonance space can be easily increased. Therefore, the resonance frequency when the resonance part resonates can be reduced while suppressing an increase in size of the resonance part. Therefore, the frequency of the sound that is reduced with respect to the sound that is incident on the sound insulating part can be adjusted while suppressing an increase in size of the sound insulating part.

[0011] The reference symbols in parentheses attached to each component indicate an example of the correspondence between the component and specific components described in the embodiments described below. [Brief description of the drawings]

[0012] [Figure 1] 1 is a front view of a sound insulation structure to which a sound insulation part according to a first embodiment is applied. [Diagram 2] 1 is a side view of a sound insulation structure to which a sound insulation part according to a first embodiment is applied. [Diagram 3] 1 is a perspective view of a sound insulation structure to which a sound insulation part according to a first embodiment is applied. [Figure 4] FIG. 2 is a perspective view of a sound insulating part according to the first embodiment. [Diagram 5] FIG. 5 is a cross-sectional view taken along the line V-V of FIG. [Figure 6] 6 is a cross-sectional view taken along the line VI-VI shown in FIG. [Figure 7] FIG. [Figure 8] 8 is a cross-sectional view taken along the line VIII-VIII in FIG. 7. [Figure 9] FIG. 11 is a perspective view of a sound insulating part according to a second embodiment. [Figure 10] 10 is a cross-sectional view taken along the line XX in FIG. [Figure 11] 10 is a cross-sectional view taken along the line XI-XI of FIG. [Figure 12] FIG. 11 is a diagram showing the transmission loss of a sound insulating part according to the second embodiment. [Figure 13] FIG. 11 is a cross-sectional view of a sound insulating part according to a third embodiment. [Figure 14] 14 is a cross-sectional view taken along the line XIV-XIV of FIG. 13. [Figure 15] FIG. 13 is a cross-sectional view of a sound insulating part according to a fourth embodiment. [Figure 16] FIG. 13 is a diagram showing the transmission loss of a sound insulating part according to the fourth embodiment. [Figure 17] FIG. 13 is a cross-sectional view of a sound insulating part according to a fifth embodiment. [Figure 18] FIG. 13 is a cross-sectional view of a sound insulation part according to a sixth embodiment. [Figure 19] FIG. 13 is a schematic diagram showing a staircase portion according to a sixth embodiment. [Figure 20] FIG. 13 is a diagram showing the transmission loss of a sound insulating portion according to the sixth embodiment. [Figure 21] FIG. 13 is a perspective view of a speaker to which a sound insulation structure according to a seventh embodiment is applied. [Figure 22] 22 is a cross-sectional view taken along line XXII-XXII of FIG. 21. [Diagram 23] 23 is a cross-sectional view taken along the line XXIII-XXIII in FIG. 21. [Figure 24] FIG. 13 is a perspective view of a sound insulation structure to which a sound insulation part according to a seventh embodiment is applied. [Diagram 25] FIG. 13 is a perspective view of a sound insulating part according to a seventh embodiment. [Figure 26] 26 is a cross-sectional view taken along the line XXVI-XXVI of FIG. 25. [Figure 27] 26 is a cross-sectional view taken along line XXVII-XXVII of FIG. 25. [Figure 28] 13 is a diagram showing the difference between when the outer rolled portion on one side has an outer stepped portion on one side and when it does not have one. FIG. [Figure 29] FIG. 13 is a diagram showing the transmission loss of a sound insulating portion according to the seventh embodiment. [Diagram 30] FIG. 13 is a diagram showing the configuration of an experiment carried out to evaluate the sound insulation structure according to the seventh embodiment alone. [Diagram 31] FIG. 13 is a diagram showing the results of an experiment carried out to evaluate the sound insulation structure of the seventh embodiment alone. [Diagram 32] FIG. 13 is a diagram showing the configuration of an experiment carried out to evaluate the sound insulation structure of the seventh embodiment in a state where it is attached to a speaker. [Diagram 33] FIG. 13 is a diagram showing the results of an experiment carried out to evaluate the sound insulation structure of the seventh embodiment in a state where it is attached to a speaker. [Diagram 34] FIG. 13 is a diagram showing a configuration diagram of an experiment conducted with a sound-insulating structure in the seventh embodiment or a comparative member attached to a speaker. [Diagram 35]FIG. 13 is a diagram showing the results of an experiment conducted with the sound-insulating structure in the seventh embodiment or a comparative member attached to a speaker. [Diagram 36] FIG. 13 is a cross-sectional view of a sound insulation part according to an eighth embodiment. [Figure 37] This is a cross-sectional view taken along line XXXVII-XXXVII of Figure 36. [Figure 38] 38 is a cross-sectional view corresponding to FIG. 37 of a sound-proof part according to a ninth embodiment. FIG. [Figure 39] 37 in a sound-proofing part according to a tenth embodiment. FIG. [Diagram 40] FIG. 23 is a cross-sectional view of a sound-proofing part according to an eleventh embodiment. [Diagram 41] FIG. 41 is a cross-sectional view taken along the line XLI-XLI shown in FIG. 40. [Diagram 42] 42 is a diagram showing a state in which a closing part different from the closing part shown in FIG. 41 is inserted into a spiral opening of a sound-proofing part according to an eleventh embodiment. FIG. [Diagram 43] FIG. 23 is a diagram showing the transmission loss of a sound insulating portion according to an eleventh embodiment. [Diagram 44] 42 is a cross-sectional view corresponding to FIG. 41 in a sound-proof part according to a twelfth embodiment. FIG. [Diagram 45] 45 is a diagram showing a state in which the screw fastening positions in the sound-proofing part according to the twelfth embodiment are different from the screw fastening positions shown in FIG. 44. [Figure 46] 45 is a cross-sectional view corresponding to FIG. 44 of a sound-proof part according to a thirteenth embodiment. FIG. [Figure 47] 47 is a diagram showing a state in which a screw different from the screw shown in FIG. 46 is inserted into the spiral opening of the sound-proofing part according to the thirteenth embodiment. FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] Hereinafter, the embodiments of the present disclosure will be described with reference to the drawings. In the following embodiments, the same reference numerals are used for parts that are the same as or equivalent to those described in the preceding embodiments, and the description thereof may be omitted. In addition, in the embodiments, when only a part of the components is described, the components described in the preceding embodiments can be applied to the other parts of the components. In the following embodiments, each embodiment can be partially combined with each other, even if not specifically stated, as long as it does not cause any trouble in combination.

[0014] (First embodiment) A sound insulation part 10 of this embodiment will be described with reference to Figs. 1 to 8. In this embodiment, an example will be described in which the sound insulation part 10 is applied to a sound insulation structure 1 shown in Fig. 1 etc., which is used in a vehicle. As shown in Figs. 1 to 3, the sound insulation structure 1 is configured by combining a plurality of plate-shaped sound insulation parts 10. The sound insulation structure 1 is provided, for example, in a dash panel or door (not shown) provided between the inside and outside of the vehicle compartment.

[0015] Here, as shown in FIG. 2 and the like, the plate thickness direction of the plate-shaped sound insulation part 10 is defined as the first direction D1. Also, as shown in FIG. 2 and the like, a predetermined direction along the plate surface of the sound insulation part 10 and perpendicular to the first direction D1 is defined as the second direction D2, and a direction perpendicular to the first direction D1 and the second direction D2 is defined as the third direction D3. The sound insulation structure 1 of this embodiment is configured with 25 sound insulation parts 10 arranged in a row, five each in the second direction D2 and the third direction D3. The sound insulation structure 1 is arranged so that the plate surface of each sound insulation part 10 faces the dash panel or the door. Specifically, the sound insulation structure 1 is arranged so that a sound insulation opening 41 provided in a first plate surface 21 of the sound insulation part 10 described later is on the side where an object that emits sound toward the sound insulation structure 1 is present. Note that, for convenience, in FIG. 1 and the like, a reference symbol is attached to a representative one of the 25 sound insulation parts 10, and the reference symbols to the other parts are omitted.

[0016] The number of sound-insulating parts 10 constituting the sound-insulating structure 1 is not limited. The sound-insulating structure 1 may be configured with more than five sound-insulating parts 10 arranged in the second direction D2 or the third direction D3, or may be configured with fewer than five sound-insulating parts 10 arranged in the first direction D1. Also, the sound-insulating structure 1 may be configured with the sound-insulating parts 10 arranged in the first direction D1.

[0017] As shown in FIG. 4, the sound insulation part 10 has a sound insulation plate 20 and a resonating part 30. The sound insulation plate 20 forms the outer shell of the sound insulation part 10. The sound insulation plate 20 is formed in a plate shape having a substantially square shape when viewed from a direction along the first direction D1 and a plate surface in the first direction D1. That is, the sound insulation plate 20 is formed in a plate shape having a substantially square shape when viewed in a direction perpendicular to the plate surface and a size in the first direction D1 smaller than the sizes in the second direction D2 and the third direction D3. The sound insulation plate 20 is a member having a mass per unit volume larger than that of air, and is formed of, for example, resin. The sound insulation plate 20 of this embodiment is formed of nylon resin. The sound insulation plate 20 has a planar first plate surface 21 on one side in the first direction D1 and a planar second plate surface 22 on the other side in the first direction D1.

[0018] The shape of the sound-insulating plate 20 is not limited to this. The shape of the sound-insulating plate 20 when viewed from the direction along the first direction D1 may be a shape other than a square, such as a rectangle, a triangle, or a circle. The material of the sound-insulating plate 20 is not limited to nylon resin. The sound-insulating plate 20 may be made of a resin other than nylon resin, or may be made of a material other than resin, such as a metal.

[0019] The resonator 30 is a hollow portion formed inside the sound-proofing plate 20, and when sound waves are incident on the sound-proofing plate 10, the air inside the resonator 30 vibrates to generate Helmholtz resonance. As shown in Figs. 4 to 6, the resonator 30 is formed in a cylindrical shape with one end opening at the first plate surface 21 of the sound-proofing plate 20 and the other end closed inside the sound-proofing plate 20, forming a resonant space S. Specifically, the resonator 30 has a neck portion 40 extending from the first plate surface 21 toward the other side in the first direction D1, i.e., toward the inside of the sound-proofing plate 20, and a spiral portion 50 formed by bending inside the sound-proofing plate 20. The resonator 30 has a hollow inside the resonant space S, and the opening side communicates with the outside of the sound-proofing plate 20, so that the resonant space S is filled with air.

[0020] The resonator 30 is formed by connecting the neck 40 and the spiral 50. This allows the space formed by the neck 40 and the space formed by the spiral 50 to communicate with each other. That is, the resonator space S is composed of the space formed by the neck 40 and the space formed by the spiral 50. The neck 40 and the spiral 50 have cross-sectional shapes perpendicular to the direction in which their respective paths extend, each of which is formed in a substantially perfect circle shape. In other words, the resonator 30 has a cross-sectional shape perpendicular to the direction in which it extends from one end to the other end, each of which is formed in a substantially perfect circle shape.

[0021] 4 and 5, the neck portion 40 is formed along the first direction D1 from approximately the center of the first plate surface 21 to approximately the center of the sound insulation board 20 in the first direction D1. The neck portion 40 has a sound insulating opening 41 on one side in the first direction D1 that communicates with the outside of the sound insulation board 20 at the first plate surface 21, and a communication portion 42 on the other side in the first direction D1 that communicates with the spiral portion 50. The sound insulating opening 41 communicates with the resonance space S. The neck portion 40 has a constant opening area from the sound insulating opening 41 to the communication portion 42 that is perpendicular to the direction in which the path extends, i.e., the opening area perpendicular to the first direction D1.

[0022] As shown in FIG. 6, the spiral portion 50 is formed in a spiral shape in which the diameter increases from the inside to the outside and a circle is drawn. The spiral portion 50 of this embodiment has a spiral shape with two turns. The spiral portion 50 has a first end 51 that communicates with the communication portion 42 of the neck portion 40 at its inner end, and a second end 52 that is closed by the sound insulation plate material 20 at its outer end. The spiral portion 50 also has a resonance surface 53 that forms a part of the resonance space S through which sound waves are propagated. The spiral portion 50 is formed around the communication portion 42 of the neck portion 40 as the center. In other words, the spiral portion 50 is formed at a position that overlaps with a part of the neck portion 40 in the first direction D1. The spiral portion 50 is formed so that the first end 51 and the second end 52 overlap in the second direction D2. Hereinafter, the first end 51 side of the spiral portion 50 may be referred to as the starting end side, and the second end 52 may be referred to as the terminal end side.

[0023] The spiral portion 50 has a constant opening area perpendicular to the direction in which the path extends, i.e., perpendicular to the direction along the spiral shape, from the first end 51 to the second end 52. In other words, the spiral portion 50 has a constant inner diameter from the starting end side to the terminal end side. The direction in which the path of the spiral portion 50 extends is the direction along which the tangent to the inner circumference of the spiral portion 50 extends in the cross section of the spiral portion 50 shown in FIG. 6. The spiral portion 50 is formed such that the opening area perpendicular to the direction in which the path extends is equal to the opening area perpendicular to the direction in which the path extends in the neck portion 40. The spiral portion 50 of this embodiment functions as a bending portion.

[0024] The length of the spiral portion 50 thus formed in the direction along the spiral shape is greater than the length of the neck portion 40 in the first direction D1. Here, the length of the neck portion 40 in the first direction D1 is referred to as the neck length, the length of the spiral portion 50 in the direction along the spiral shape is referred to as the spiral length, the volume of the space formed by the neck portion 40 is referred to as the neck volume, and the volume of the space formed by the spiral portion 50 is referred to as the spiral volume. The resonator portion 30 formed by the neck portion 40 and the spiral portion 50, each of which has the same opening area perpendicular to the path, has a spiral volume greater than the neck volume.

[0025] Therefore, when sound waves are incident on the sound-insulating part 10 and propagate through the sound-insulating opening 41, Helmholtz resonance occurs, and the air in the resonating part 30 resonates at a resonant frequency according to the neck length and the volute volume. As a result, the sound-insulating part 10 can exhibit sound-insulating performance by reducing the amplitude of sound waves in a frequency band near the resonant frequency of the air resonating in the resonating part 30, among the sound waves incident on the sound-insulating structure 1. Hereinafter, the resonant frequency of the air resonating in the resonating part 30 is also simply referred to as the resonant frequency of the resonating part 30. Furthermore, among the frequencies contained in the sound waves incident on the sound-insulating part 10, the frequency band near the resonant frequency of the resonating part 30 is also referred to as a specific frequency.

[0026] As described above, the sound insulating part 10 of the present embodiment has the spiral part 50 formed by bending the resonating part 30 inside the sound insulating plate 20. When sound waves are incident toward the sound insulating part 10, the sound insulating part 10 exhibits sound insulating performance by generating Helmholtz resonance in the resonating part 30, thereby resonating the air inside the resonating part 30 and reducing sounds of a specific frequency among the sound waves incident toward the sound insulating part 10.

[0027] In the sound insulating part 10 that obtains sound insulating performance by Helmholtz resonance, the smaller the specific frequency band at which the sound insulating performance is exhibited, the smaller the resonant frequency band of the resonating part 30 must be. As described above, the resonant frequency of the resonating part 30 is determined according to the neck length and the spiral volume. And, the smaller the specific frequency band at which the sound insulating part 10 exhibits sound insulating performance, the larger the size of the spiral volume must be.

[0028] The sound insulation part 10 of the present embodiment is applied to a sound insulation structure 1 used in a vehicle. When the vehicle is moving, noises due to the external environment, such as wind noise and road noise, are generated. In addition, the vehicle may be equipped with components that generate drive noise, such as a fan and an inverter. These noises due to the external environment and the drive noise of the components are noises for the occupants of the vehicle, and are a factor that deteriorates the riding comfort of the occupants. These noises include a wide frequency band from low frequency bands to high frequency bands. For this reason, it is desired that the sound insulation part 10 exhibits sound insulation performance in a wide frequency band from low frequency bands to high frequency bands.

[0029] Here, if the resonating portion 30 does not have a bending portion inside the sound-insulating plate 20, there is a risk that the volume formed inside the sound-insulating plate 20 will be limited. For example, as in the comparative sound-insulating portion 100 shown in Figures 7 and 8, which is a comparative example, the comparative resonating portion 110 is composed of a comparative neck portion 120 and a cylindrical hollow portion 130 that is connected to the comparative neck portion 120 and has an axis in the first direction D1.

[0030] In this case, the cylindrical cavity 130 is formed on the other side of the comparative neck portion 120 in the first direction D1. That is, the cylindrical cavity 130 cannot be formed at a position overlapping with the comparative neck portion 120 in the first direction D1. In other words, the cylindrical cavity 130 cannot be formed around the comparative neck portion 120. In the case of such a configuration, the position in the first direction D1 where the cylindrical cavity 130 can be formed inside the comparative sound-insulating part 100 is limited. As a result, the volume of the space formed by the cylindrical cavity 130 is limited by the size of the comparative sound-insulating part 100 in the first direction D1. Therefore, it is difficult to increase the volume of the space formed by the cylindrical cavity 130 inside the comparative sound-insulating part 100.

[0031] For example, in the sound insulation part 10 and the comparative sound insulation part 100, when the neck part 40 and the comparative neck part 120 have the same size in the first direction D1 and the same shape, it is attempted to ensure that the volume of the space formed by the cylindrical cavity part 130 is the same as the volume of the spiral. However, since the size of the cylindrical cavity part 130 in the first direction D1 is limited by the size of the comparative sound insulation part 100 in the first direction D1, it is smaller than the size of the spiral part 50 in the first direction D1. For this reason, it is necessary to make at least one of the size of the comparative sound insulation part 100 in the second direction D2 and the size of the comparative sound insulation part 100 in the third direction D3 larger than that of the sound insulation part 10. In other words, when the air inside the cylindrical cavity part 130 is resonated at the same frequency as the resonant frequency of the resonant part 30, the comparative sound insulation part 100 will be larger than the sound insulation part 10, which is not preferable.

[0032] Furthermore, the fact that the comparative sound-insulating portion 100 is larger than the sound-insulating portion 10 causes an increase in the weight of the sound-insulating structure 1 when the comparative sound-insulating portion 100 is applied to the sound-insulating structure 1. For this reason, when the sound-insulating structure 1 to which the comparative sound-insulating portion 100 is applied is mounted on a vehicle, the increase in the weight of the sound-insulating structure 1 causes a decrease in the fuel efficiency of the vehicle, which is even more undesirable.

[0033] In contrast, according to the sound insulation part 10 of this embodiment having the spiral part 50 formed by bending inside the sound-insulating plate 20, it is easy to increase the volume of the spiral formed inside the sound insulation part 10. Therefore, it is possible to reduce the resonance frequency of the resonance part 30 while suppressing an increase in size of the resonance part 30. Therefore, even if the sound insulation performance required for the sound insulation part 10 is for sounds in a wide frequency band from low to high frequencies, the sound insulation part 10 can reduce sounds in a wide frequency band with respect to sounds incident on the sound insulation part 10 without increasing in size.

[0034] In addition, in the case of a sound insulation structure having a cylindrical base and a plurality of weights having a mass greater than that of the base, such as the sound insulation structure described in Patent Document 1, the weight of the sound insulation structure tends to increase due to the inclusion of a plurality of heavy objects such as weights. Furthermore, in the case of a sound insulation structure having a plurality of components each consisting of a base and a weight, the manufacturing cost of the sound insulation structure tends to increase.

[0035] In contrast to these, according to the sound-insulating part 10 of this embodiment, the resonating part 30 is constructed by a cavity formed inside the sound-insulating board 20, which makes it easier to reduce the weight of the sound-insulating part 10 and, since the number of parts is limited, manufacturing costs can also be easily reduced.

[0036] Furthermore, according to the above embodiment, the following effects can be obtained.

[0037] (1) In the above embodiment, the resonance space S of the resonance unit 30 is filled with air.

[0038] This allows the resonance portion 30 to be formed more easily than when the resonance space S is filled with a gas other than air, such as gas, or with a liquid such as water.

[0039] (2) In the above embodiment, the resonator unit 30 has a circular cross section perpendicular to the direction in which it extends from one end to the other end.

[0040] With this, compared to a configuration in which the cross-sectional shape perpendicular to the direction extending from one end of the resonance part 30 to the other end has corners such as a rectangle, diffuse reflection is less likely to occur when the sound propagates through the resonance space S. Therefore, it is easier to stabilize the resonance frequency of the resonance part 30.

[0041] (3) In the above embodiment, the spiral portion 50 is formed in a spiral shape.

[0042] This makes it easier to increase the length of the spiral portion 50 in the direction along the spiral shape when forming the resonance space S within the sound-proofing board 20, and makes it easier to increase the volume of the space formed by the spiral portion 50. Therefore, even if the resonance frequency of the resonance portion 30 required to obtain the required sound-proofing performance is relatively small, it is easy to make the resonance frequency of the resonance portion 30 correspond to the required frequency.

[0043] Second embodiment Next, the second embodiment will be described with reference to Figs. 9 to 12. This embodiment differs from the first embodiment in that a plurality of resonating portions 30a, 30b are formed in the sound insulating portion 10. The rest is the same as the first embodiment. Therefore, in this embodiment, the portions different from the first embodiment will be mainly described, and the description of the portions similar to the first embodiment may be omitted.

[0044] As shown in Figs. 9 to 11, the sound insulation part 10 of this embodiment has two resonating parts 30a and 30b. The two resonating parts 30a and 30b are formed in the sound insulation board 20, shifted from each other in the first direction D1. Hereinafter, of the two resonating parts 30a and 30b, the one on one side in the first direction D1 is called the first resonating part 30a, and the other on the other side in the first direction D1 is called the second resonating part 30b. The first resonating part 30a and the second resonating part 30b are formed in a hollow shape in the sound insulation board 20, and when sound waves are incident on the sound insulation part 10, the air inside each resonating part vibrates, generating Helmholtz resonance.

[0045] The first resonating portion 30a and the second resonating portion 30b of the present embodiment are formed so that their internal volumes are different and the resonant frequencies of the air that resonates therein are different from each other.

[0046] As shown in Fig. 9 and Fig. 10, the first resonating portion 30a has a first neck portion 40a extending from the first plate surface 21 toward the other side in the first direction D1, and a first spiral portion 50a formed by bending inside the sound insulation plate 20. The first resonating portion 30a is formed by connecting the first neck portion 40a and the first spiral portion 50a. This allows the space formed by the first neck portion 40a to communicate with the space formed by the first spiral portion 50a. The first neck portion 40a and the first spiral portion 50a have cross-sectional shapes that are substantially circular in shape perpendicular to the direction in which their respective paths extend.

[0047] The first neck portion 40a is formed along the first direction D1 from approximately the center of the first plate surface 21 to approximately the center in the first direction D1 of the sound insulation board 20. The first neck portion 40a has a first sound insulating opening portion 41a that opens at the first plate surface 21 on one side in the first direction D1, and a first communication portion 42a that communicates with the first spiral portion 50a on the other side in the first direction D1. The opening area of ​​the first neck portion 40a perpendicular to the first direction D1 is constant from the first sound insulating opening portion 41a to the first communication portion 42a.

[0048] As shown in Fig. 10, the first spiral portion 50a is formed in a spiral shape that is formed so that the diameter increases from the inside to the outside and draws a circle. In this embodiment, the first spiral portion 50a is in a spiral shape with more than three turns. The first spiral portion 50a is formed around the first communicating portion 42a of the first neck portion 40a, with the first spiral portion 50a at the center. In other words, the first spiral portion 50a is formed at a position that overlaps with a part of the first neck portion 40a in the first direction D1.

[0049] The first spiral portion 50a has a constant opening area perpendicular to the direction along which the path of the first spiral portion 50a extends from the inner end to the outer end, and has a constant inner diameter from the inner end to the outer end. The first spiral portion 50a is formed so that the opening area perpendicular to the direction along which the path extends is equal to the opening area perpendicular to the direction along which the path extends in the first neck portion 40a.

[0050] The second resonating portion 30b has a second neck portion 40b extending from the first plate surface 21 toward the other side in the first direction D1, and a second spiral portion 50b formed by bending inside the sound insulation plate 20. The second resonating portion 30b is formed by connecting the second neck portion 40b and the second spiral portion 50b. This allows the space formed by the second neck portion 40b and the space formed by the second spiral portion 50b to communicate with each other. The second neck portion 40b and the second spiral portion 50b have cross-sectional shapes that are substantially circular and perpendicular to the direction in which their respective paths extend.

[0051] The second neck portion 40b is formed along the first direction D1 from a position shifted in the second direction D2 from approximately the center of the first plate surface 21 to the other side in the first direction D1 from approximately the center in the first direction D1 of the sound insulation plate 20. In other words, the second neck portion 40b is formed at a position different from the first neck portion 40a, and is formed to be larger in size in the first direction D1 than the first neck portion 40a.

[0052] The second neck portion 40b has, on one side in the first direction D1, a second sound insulating opening 41b that opens at the first plate surface 21, and, on the other side in the first direction D1, a second communication portion 42b that communicates with the second spiral portion 50b. The second neck portion 40b has a constant opening area perpendicular to the first direction D1 from the second sound insulating opening 41b to the second communication portion 42b.

[0053] As shown in FIG. 11, the second spiral portion 50b is formed in a spiral shape in which the diameter increases from the inside to the outside and the circle is drawn. The second spiral portion 50b of this embodiment has fewer turns than the first spiral portion 50a, and is a spiral shape with fewer turns than two. The second spiral portion 50b is formed shifted to the other side of the first direction D1 from the first spiral portion 50a. In other words, the first spiral portion 50a and the second spiral portion 50b are arranged side by side in the first direction D1 with a predetermined interval therebetween. The second spiral portion 50b is formed around the second communicating portion 42b of the second neck portion 40b as the center. In other words, the second spiral portion 50b is formed at a position overlapping a part of the second neck portion 40b in the first direction D1.

[0054] The second spiral portion 50b has a constant opening area perpendicular to the direction along which the path of the second spiral portion 50b extends from the inner end to the outer end, and has a constant inner diameter from the inner end to the outer end. The second spiral portion 50b is formed such that the opening area perpendicular to the direction along which the path extends is equal to the opening area perpendicular to the direction in which the path of the second neck portion 40b extends, and is equal to the opening area perpendicular to the direction in which the path of the first spiral portion 50a extends.

[0055] The second spiral portion 50b thus formed has a length in a direction along the spiral shape that is shorter than the length in a direction along the spiral shape of the first spiral portion 50a. Here, the length in a direction along the spiral shape of the first spiral portion 50a is defined as the first spiral length, and the length in a direction along the spiral shape of the second spiral portion 50b is defined as the second spiral length. Also, the volume of the space formed by the first spiral portion 50a is defined as the first spiral volume, and the volume of the space formed by the second spiral portion 50b is defined as the second spiral volume. The first spiral portion 50a having a first spiral length longer than the second spiral length has a first spiral volume larger than the second spiral volume. The first spiral portion 50a and the second spiral portion 50b in this embodiment function as bending portions.

[0056] When sound waves are incident on the first resonating portion 30a and the second resonating portion 30b of the sound insulating portion 10 thus formed, Helmholtz resonance occurs, and the air in the first resonating portion 30a and the second resonating portion 30b resonates at their respective resonant frequencies. The first resonating portion 30a, which has a first spiral volume larger than the second spiral volume, resonates at a lower resonant frequency than the second resonating portion 30b.

[0057] As a result, the sound-insulating portion 10 can exhibit sound-insulating performance for sound waves incident on the sound-insulating structure 1, the sound waves being in a frequency band near the resonant frequency of air that resonates in the first resonating portion 30a and the sound waves being in a frequency band near the resonant frequency of air that resonates in the second resonating portion 30b.

[0058] FIG. 12 shows the difference in sound insulation performance between when the sound insulation structure 1 having the sound insulation part 10 of this embodiment is provided on the dash panel and when it is not provided. The solid line shown in FIG. 12 indicates the transmission loss when the sound insulation structure 1 having the sound insulation part 10 of this embodiment is provided on the dash panel. The broken line shown in FIG. 12 indicates the transmission loss of the dash panel without the sound insulation structure 1. As shown in FIG. 12, the sound insulation structure 1 having the sound insulation part 10 of this embodiment can exhibit sound insulation performance with prominent transmission loss in two different frequency bands. Specifically, the sound insulation part 10 of this embodiment exhibits a higher transmission loss than the other frequency bands in two frequency bands, and the lower frequency band exhibits sound insulation performance exhibited by the first resonance part 30a, and the higher frequency band exhibits sound insulation performance exhibited by the second resonance part 30b.

[0059] The other configurations are the same as those of the first embodiment. The sound insulating portion 10 of this embodiment can obtain the same effects as those of the first embodiment, which are achieved by a configuration similar to or equivalent to those of the first embodiment.

[0060] The sound insulating section 10 of this embodiment includes a first resonating section 30a and a second resonating section 30b. The first resonating section 30a includes a first spiral section 50a. The second resonating section 30b includes a second spiral section 50b.

[0061] According to this, the sound insulating portion 10 can generate Helmholtz resonance in each of the first resonating portion 30a and the second resonating portion 30b.

[0062] Furthermore, according to the above embodiment, the following effects can be obtained.

[0063] (1) In the above embodiment, the first spiral portion 50a and the second spiral portion 50b have first and second spiral volumes which are different from each other.

[0064] This allows the resonant frequency of air resonating in the first resonating portion 30a and the resonant frequency of air resonating in the second resonating portion 30b to be different in magnitude in the sound insulating portion 10. Therefore, the sound insulating portion 10 can exhibit sound insulating performance for sound waves in a frequency band near the resonant frequency of the first resonating portion 30a and a frequency band near the resonant frequency of air resonating in the second resonating portion 30b.

[0065] (2) In the above embodiment, the first spiral portion 50a and the second spiral portion 50b are provided side by side at a predetermined interval in the first direction D1.

[0066] This makes it easier to increase the length of each of the first and second spiral portions 50a and 50b in the direction along the spiral shape, and makes it easier to increase the volume of the space formed by each of the first and second spiral portions 50a and 50b. Therefore, even if the resonant frequencies of the first and second resonant portions 30a and 30b required to obtain the required sound insulation performance are relatively small, it is easy to make the resonant frequencies of the first and second resonant portions 30a and 30b correspond to the required frequencies.

[0067] (First modified example of the second embodiment) In the above-described second embodiment, an example has been described in which the sound insulating portion 10 has the two resonating portions 30a and 30b, but the present invention is not limited to this.

[0068] For example, the sound insulating section 10 may have three or more resonating sections 30.

[0069] (Second modified example of the second embodiment) In the above-described second embodiment, the example in which the first resonance portion 30a and the second resonance portion 30b are formed to be shifted from each other in the first direction D1 has been described, but the present invention is not limited to this.

[0070] For example, the first resonating portion 30a and the second resonating portion 30b may be formed to be shifted in the second direction D2 or the third direction D3.

[0071] Third embodiment Next, a third embodiment will be described with reference to Figs. 13 and 14. In this embodiment, the shapes and positions of the first and second resonating portions 30a and 30b are different from those of the second embodiment. The rest of the third embodiment is the same as the second embodiment. Therefore, in this embodiment, the differences from the second embodiment will be mainly described, and the description of the same parts as the second embodiment may be omitted.

[0072] 13 and 14, the first spiral portion 50a and the second spiral portion 50b of this embodiment are formed at overlapping positions in the first direction D1 inside the sound insulation board 20. That is, the first spiral portion 50a and the second spiral portion 50b are formed at the same position in the first direction D1. Moreover, the first spiral portion 50a and the second spiral portion 50b of this embodiment are formed so that their internal volumes are approximately the same and the resonant frequencies of the air resonating inside them are approximately the same.

[0073] The first spiral portion 50a in this embodiment is formed in a spiral shape that starts from a position slightly shifted in the third direction D3 from the center of the sound insulation unit 10 when viewed from the direction along the first direction D1, and draws a square whose size increases from the inside to the outside. The first spiral portion 50a in this embodiment has a spiral shape with more than two turns. The first spiral portion 50a has a rectangular cross-sectional shape perpendicular to the direction in which each path extends, and is specifically formed in a substantially square shape.

[0074] Moreover, the second spiral portion 50b of this embodiment is formed in a spiral shape formed to draw a square whose size increases from the inside to the outside, starting from a position slightly shifted in the third direction D3 from the center of the sound insulation unit 10 viewed from the direction along the first direction D1. The starting point of the spiral shape of the second spiral portion 50b is in a position different from the starting point of the spiral shape of the first spiral portion 50a. Specifically, the starting point of the spiral shape of the second spiral portion 50b is positioned at a position that is point-symmetrical to the starting point of the spiral shape of the first spiral portion 50a, with the center of the sound insulation unit 10 viewed from the direction along the first direction D1 as the reference point.

[0075] The second spiral portion 50b has a shape that is point-symmetrical with respect to the first spiral portion 50a, with the center of the sound insulation portion 10 viewed from the direction along the first direction D1 as a reference point. Specifically, the second spiral portion 50b has the same number of turns and winding direction as the first spiral portion 50a, and is a spiral shape with more than two turns. The second spiral portion 50b is disposed in a gap in the spiral-shaped first spiral portion 50a. The second spiral portion 50b has a rectangular cross-sectional shape perpendicular to the direction in which each path extends, and is formed into a substantially square shape.

[0076] The second spiral portion 50b thus formed has a length in a direction along the spiral shape that is substantially equal to the length in a direction along the spiral shape of the first spiral portion 50a. That is, the first spiral portion 50a and the second spiral portion 50b have substantially equal first and second spiral lengths, and substantially equal first and second spiral volumes.

[0077] When sound waves are incident on the first resonating portion 30a and the second resonating portion 30b, Helmholtz resonance occurs in the sound insulating portion 10, and the air in the first resonating portion 30a and the air in the second resonating portion 30b resonate at approximately the same resonant frequency. This allows the sound insulating portion 10 to exhibit sound insulating performance against sound waves in one frequency band near the approximately equal resonant frequencies of the first resonating portion 30a and the second resonating portion 30b, among the sound waves incident on the sound insulating structure 1.

[0078] Therefore, the sound insulating portion 10 can exhibit high sound insulating performance for one frequency band, compared to a configuration having only either the first resonating portion 30a or the second resonating portion 30b.

[0079] The other configurations are the same as those of the first embodiment. The sound insulating portion 10 of this embodiment can obtain the same effects as those of the first embodiment, which are achieved by a configuration similar to or equivalent to those of the first embodiment.

[0080] Further, in the sound insulation part 10 of the present embodiment, the first spiral part 50a and the second spiral part 50b are provided so as to overlap with each other in the first direction D1.

[0081] This allows the size of the sound insulation part 10 in the first direction D1 to be smaller than in a configuration in which the first spiral part 50a and the second spiral part 50b are arranged side by side at a predetermined interval in the first direction D1.

[0082] Furthermore, according to the above embodiment, the following effects can be obtained.

[0083] (1) In the above embodiment, the first spiral portion 50a and the second spiral portion 50b are symmetrical with respect to the center of the sound insulation unit 10 when viewed from a direction along the first direction D1. The first spiral portion 50a and the second spiral portion 50b are disposed in the gap between each other.

[0084] According to this, when the first spiral portion 50a and the second spiral portion 50b are formed at the same position in the first direction D1, they can be formed without interfering with each other. Therefore, it is easier to reduce the size of the sound insulation part 10 in the second direction D2 and the third direction D3 compared to a case where the first spiral portion 50a and the second spiral portion 50b are not formed in this manner.

[0085] (2) In the above embodiment, the first spiral portion 50a and the second spiral portion 50b are formed to have a rectangular cross-sectional shape perpendicular to the direction in which their paths extend.

[0086] This makes it easier to form the first spiral portion 50a and the second spiral portion 50b compared to when the cross-sectional shape perpendicular to the extension direction of the path of each of the first spiral portion 50a and the second spiral portion 50b is formed into a polygonal shape other than a rectangle, such as a triangular shape or a pentagonal shape.

[0087] (Fourth embodiment) Next, a fourth embodiment will be described with reference to Fig. 15 and Fig. 16. This embodiment differs from the second embodiment in that the sound-insulating portion 10 is provided with a sound-absorbing material 60. The rest of the fourth embodiment is similar to the second embodiment. Therefore, in this embodiment, the differences from the second embodiment will be mainly described, and the description of the similarities between the second embodiment and the fourth embodiment may be omitted.

[0088] As shown in FIG. 15, the sound-insulating part 10 of this embodiment is provided with a sound-absorbing material 60 at the end of the first spiral part 50a on the terminal side blocked by the sound-insulating plate material 20. The sound-absorbing material 60 can be made of a material with a relatively small sound absorption coefficient. For example, the sound-absorbing material 60 can be made of a material that consumes the energy of the incident sound as heat energy inside itself, such as urethane foam, rubber, or glass wool, which has a sound absorption coefficient of 0.1. The sound absorption coefficient indicates the ratio of the energy of the reflected sound to the energy of the incident sound. In this embodiment, the sound-absorbing material 60 functions as an energy reduction part that reduces the energy of the sound wave propagated into the resonance space S.

[0089] The difference in transmission loss of sound insulation part 10 due to the provision of sound-absorbing material 60 is shown in Fig. 16. The solid line in Fig. 16 shows the transmission loss of sound insulation part 10 provided with sound-absorbing material 60. The dashed line shows the transmission loss of sound insulation part 10 without sound-absorbing material 60.

[0090] 16, in the case of a configuration in which the sound-absorbing material 60 is not provided, the sound-insulating portion 10 has outstanding sound-insulating performance in a predetermined frequency band. However, the frequency band in which the sound-insulating performance is exhibited is relatively narrow.

[0091] In contrast, in the configuration of this embodiment in which the sound-absorbing material 60 is provided, when the air inside the first spiral portion 50a resonates, the sound is absorbed by the sound-absorbing material 60. Then, around the sound-absorbing material 60 on the terminal side, air resonates at a lower resonant frequency compared to the resonant frequency of the air resonating at the starting end. Then, the resonance generated in the first spiral portion 50a is dulled. As a result, as shown in FIG. 16, the sound-insulating portion 10 has a smaller transmission loss at frequencies with the same transmission loss, but the frequency band in which the sound-insulating performance is exhibited can be made wider than in a configuration in which the sound-absorbing material 60 is not provided.

[0092] The other configurations are the same as those of the second embodiment. The sound insulating portion 10 of this embodiment can obtain the same effects as those of the second embodiment, which are achieved by a configuration similar to or equivalent to those of the second embodiment.

[0093] The sound absorbing material 60 may be provided in the second spiral portion 50b in addition to the first spiral portion 50a, or may be provided only in the second spiral portion 50b.

[0094] Fifth embodiment Next, the fifth embodiment will be described with reference to Fig. 17. This embodiment differs from the fourth embodiment in that the sound absorbing material 60 is replaced with a viscoelastic body 65 and a vibrating body 66. The rest is the same as the fourth embodiment. Therefore, in this embodiment, the differences from the fourth embodiment will be mainly described, and the description of the same parts as the fourth embodiment may be omitted.

[0095] 17, sound insulation part 10 of the present embodiment is provided with a viscoelastic body 65 and a vibrating body 66 inside first spiral part 50a. Specifically, a viscoelastically deformable viscoelastic body 65 and a vibrating vibrating body 66 are provided at an end part on the terminal side blocked by sound insulation plate 20 inside first spiral part 50a. Vibrating body 66 is attached to viscoelastic body 65, and can move integrally with viscoelastic body 65 when viscoelastic body 65 is viscoelastically deformed.

[0096] The viscoelastic body 65 is made of a viscoelastically deformable elastic member such as rubber or a spring. The vibrating body 66 is made of a metal such as iron that does not deform viscoelastically. The material of the vibrating body 66 is not limited to iron, and may be a metal other than iron such as lead, or a material other than metal such as resin.

[0097] The operation of the sound insulation unit 10 when such a viscoelastic body 65 and a vibrating body 66 are provided in the resonating unit 30 will be described. When the viscoelastic body 65 and the vibrating body 66 are provided inside the sound insulation unit 10, when sound waves are incident on the sound insulation unit 10 and the air inside the resonating unit 30 vibrates, the vibration of the air is transmitted to the viscoelastic body 65 via the vibrating body 66. As a result, the viscoelastic body 65 expands and contracts, causing the vibrating body 66 to vibrate. Then, the position where the sound waves propagated inside the resonating unit 30 are reflected changes according to the position of the vibrating body 66 that expands and contracts, so that the resonance is damped when the air inside the resonating unit 30 resonates. In addition, the energy of the sound propagated inside the resonating unit 30 is consumed by the viscoelastic body 65 due to heat generated when the viscoelastic body 65 and the vibrating body 66 vibrate, and the resonance is damped when the air inside the resonating unit 30 resonates.

[0098] According to this, like the sound insulating part 10 of the fifth embodiment, the sound insulating part 10 has a small transmission loss at frequencies with equal transmission losses, but the frequency band in which the sound insulating part 10 exhibits sound insulating performance with equal transmission losses can be widened compared to a configuration without the viscoelastic body 65 and the vibrating body 66. In this embodiment, the viscoelastic body 65 functions as an energy reducing part that reduces the energy of the sound wave propagating into the resonance space S.

[0099] The other configuration is the same as that of the fourth embodiment. The sound insulating portion 10 of this embodiment can obtain the same effects as those of the fourth embodiment, which are achieved by a configuration similar to or equivalent to that of the fourth embodiment.

[0100] Sixth embodiment Next, a sixth embodiment will be described with reference to Figs. 18 to 20. In this embodiment, the shape of part of the resonator unit 30 is different from that of the first embodiment. The rest is the same as the first embodiment. Therefore, in this embodiment, the parts that are different from the first embodiment will be mainly described, and the description of the parts that are the same as the first embodiment may be omitted.

[0101] As shown in FIG. 18, the spiral portion 50 of this embodiment has a spiral shape with more than three turns. The resonator 30 has a step portion 54 that changes the opening area perpendicular to the direction along the spiral shape of the spiral portion 50 in a step-like manner. The step portion 54 is provided at the end of the terminal side of the spiral portion 50. The step portion 54 has an opening area perpendicular to the direction along the spiral shape that gradually decreases from the first end 51 side to the second end 52 side in the direction along the spiral shape, specifically, the opening area decreases in a step-like manner. In other words, the second end 52 of the spiral portion 50 has an inner diameter that decreases in a step-like manner from the starting end side to the terminal end side. The step portion 54 of this embodiment has an inner diameter that decreases in two steps from the starting end side to the terminal end side. In this embodiment, the step portion 54 functions as a changing portion that changes the inner diameter of the spiral portion 50.

[0102] Hereinafter, as shown in Fig. 19, of the portion of stepped portion 54 in which the inner diameter decreases in two steps from the starting end side to the terminal end side, the portion where the inner diameter decreases in the first step is also referred to as first step surface 541, and the portion where the inner diameter decreases in the second step is also referred to as second step surface 542. Also, of spiral portion 50, the surface formed in the portion farthest from first end 51 is also referred to as terminal surface 543. Note that Fig. 19 is a schematic diagram showing curved stepped portion 54 in a linear manner.

[0103] The operation of sound insulation unit 10 when spiral portion 50 has step portion 54 formed in a staircase shape will be described below. When sound waves are incident on sound insulation unit 10 having step portion 54, the sound waves are propagated into spiral portion 50 via neck portion 40. The sound waves propagated into spiral portion 50 are reflected by resonance surface 53 of spiral portion 50.

[0104] Here, the sound waves propagating to the staircase portion 54 are reflected at each portion where the inner diameter changes inside the staircase portion 54. For example, as in this embodiment, inside the staircase portion 54, where the inner diameter decreases in two steps from the starting end side to the terminal end side, the sound waves are reflected at each of the first step surface 541, the second step surface 542, and the terminal end surface 543. Therefore, in the staircase portion 54, there are three types of sound waves: a sound wave reflected at the first step surface 541, a sound wave reflected at the second step surface 542, and a sound wave reflected at the terminal end surface 543. As a result, the air inside the resonator 30 resonates with three resonant frequencies due to these three types of sound waves.

[0105] Therefore, the sound insulating portion 10 can obtain sound insulating performance against sound waves in frequency bands near the three resonant frequencies among the sound waves incident on the sound insulating structure 1.

[0106] Here, the length in the direction along the spiral shape from the first end 51 to the first step surface 541 is the first step length L1, and the length in the direction along the spiral shape from the first end 51 to the second step surface 542 is the second step length L2. Also, the length in the direction along the spiral shape from the first end 51 to the terminal surface 543 is the terminal length L3. The first step length L1 is shorter than the second step length L2 and the terminal length L3. Also, the second step length L2 is shorter than the terminal length L3. That is, the terminal length L3 surface is longer than the first step length L1 and the second step length L2.

[0107] The sound insulation performance of the sound insulation part 10 of this embodiment configured as described above is shown in FIG. 20. As shown in FIG. 20, the sound insulation part 10 of this embodiment has outstanding sound insulation performance in three different frequency bands. Specifically, the sound insulation part 10 exhibits sound insulation performance in the highest frequency band among the three frequency bands in which the sound insulation performance is exhibited, due to air resonance caused by sound waves reflected by the first step surface 541. The sound insulation part 10 exhibits sound insulation performance in the second highest frequency band due to air resonance caused by sound waves reflected by the second step surface 542, and exhibits sound insulation performance in the lowest frequency band due to air resonance caused by sound waves reflected by the end surface 543.

[0108] 20 indicates the transmission loss caused by air resonance due to sound waves reflected at the first step surface 541, and line b shown in Fig. 20 indicates the transmission loss caused by air resonance due to sound waves reflected at the second step surface 542. Line c shown in Fig. 20 indicates the transmission loss caused by air resonance due to sound waves reflected at the terminal surface 543.

[0109] The length along each of the spiral shapes from first end 51 to first step surface 541, second step surface 542, and terminal surface 543 is appropriately set according to the frequency band in which the required sound insulation performance is obtained in sound insulation section 10.

[0110] The other configurations are the same as those of the first embodiment. The sound insulating portion 10 of this embodiment can obtain the same effects as those of the first embodiment, which are achieved by a configuration similar to or equivalent to those of the first embodiment.

[0111] Further, the sound insulating portion 10 of this embodiment has a stepped portion 54 that changes the inner diameter of the spiral portion 50 .

[0112] As a result, sound waves propagating within the resonance space S can be reflected at the points where the inner diameter of the spiral section 50 changes, and sound-proofing performance can be achieved for multiple frequency bands through the resonance of the air caused by the sound waves reflected at each of the changing points.

[0113] Furthermore, according to the above embodiment, the following effects can be obtained.

[0114] (1) In the above embodiment, the spiral portion 50 has the step portion 54 that changes the inner diameter in a step-like manner.

[0115] According to this, sound waves propagating within the resonance space S can be reflected by each step of the staircase section 54, and sound insulation performance can be exerted against a plurality of frequency bands according to the number of steps.

[0116] (First modified example of the sixth embodiment) In the above-mentioned sixth embodiment, an example was described in which the opening area of ​​the step portion 54 perpendicular to the direction along the spiral shape decreases in a step-like manner from the starting end side to the terminal end side in the direction along the spiral shape, but this is not limited to this.

[0117] For example, the opening area of ​​the stepped portion 54 may increase stepwise in a direction perpendicular to the spiral shape from the starting end side to the terminal end side in the direction along the spiral shape.

[0118] (Second modified example of the sixth embodiment) In the sixth embodiment described above, an example in which the stepped portion 54 is provided at the end portion on the terminal side of the spiral portion 50 has been described, but the present invention is not limited to this.

[0119] For example, the stepped portion 54 may be provided approximately in the center between the first end 51 and the second end 52 of the spiral portion 50, or may be provided at the end on the starting end side.

[0120] Seventh embodiment Next, the seventh embodiment will be described with reference to Figs. 21 to 35. In this embodiment, a plurality of spiral portions 55, 56 are formed in the sound insulation part 10, and the shape of these plurality of spiral portions 55, 56 differs from that of the sixth embodiment. Also, the sound insulation part 10 of this embodiment differs from the sixth embodiment in that it is attached to a speaker SP mounted on a vehicle. The rest is the same as the sixth embodiment. Therefore, in this embodiment, the parts different from the sixth embodiment will be mainly described, and the description of the parts similar to the sixth embodiment may be omitted.

[0121] In this embodiment, as shown in Fig. 21 and Fig. 22, an example will be described in which a sound insulation structure 1 composed of a plurality of sound insulation parts 10 is applied to a speaker SP installed in a vehicle. The speaker SP is installed outside the vehicle cabin and generates an alarm sound toward the front of the vehicle. As shown in Fig. 21, the sound insulation structure 1 is attached to the rear surface of the speaker SP, opposite to the front surface where a sound generator S20 (described later) is provided, and is used to suppress unnecessary sounds toward the rear of the vehicle among the alarm sounds generated by the sound generator S20.

[0122] First, the speaker SP will be described. As shown in Figures 21 and 22, the speaker SP includes a housing S10 having a space formed therein, and a sound generating body S20 arranged inside the housing S10.

[0123] As shown in Fig. 22, the housing S10 constitutes a case for the speaker SP, and is formed in a cylindrical shape with a speaker opening S11 on the front side of the speaker SP. The sound generating body S20 is fitted into the speaker opening S11 of the housing S10 to close the opening. The housing S10 also has a sound insulation structure 1 on its rear side. Through holes S12 are formed on the rear side of the housing S10 at positions corresponding to the sound insulation openings 41 of the multiple sound insulation parts 10 of the sound insulation structure 1.

[0124] The sound generator S20 is a sound generating unit that generates a warning sound, and includes a diaphragm, a drive unit, a magnetic circuit, etc. (not shown). The sound generator S20 generates a warning sound that is emitted toward the front of the vehicle by vibrating the diaphragm with the magnetic circuit using power supplied from the drive unit.

[0125] However, a part of the warning sound emitted from the sound generating body S20 travels toward the rear of the vehicle. If this warning sound traveling toward the rear of the vehicle reaches an occupant in the vehicle cabin, it may cause a deterioration in the riding comfort of the occupant in the vehicle cabin. For this reason, the sound insulation structure 1 of this embodiment is provided behind the speaker SP, on the interior side of the vehicle cabin. As shown in FIG. 22, the sound insulation structure 1 is attached to the rear of the speaker SP so that the first direction D1, which is the plate thickness direction of the sound insulation part 10, is the front-rear direction of the vehicle. As shown in FIG. 23 and FIG. 24, the sound insulation structure 1 of this embodiment is configured with four sound insulation parts 10 lined up, two each in the second direction D2 and the third direction D3.

[0126] Next, the sound insulating part 10 of this embodiment will be described. The sound insulating part 10 of this embodiment has a square tubular resonator part 30 inside a sound insulating board 20, as shown in FIG.

[0127] As shown in FIG. 25, the resonator 30 has a neck 40 having a sound insulating opening 41 that opens on the first plate surface 21 of the sound insulating board 20 on one side in the first direction D1. The resonator 30 also has two spiral parts 55, 56 that communicate with the neck 40. The neck 40 and the two spiral parts 55, 56 have substantially square cross sections perpendicular to the direction in which their paths extend. The two spiral parts 55, 56 are formed in the sound insulating board 20, shifted in the first direction D1. Hereinafter, of the two spiral parts 55, 56, the one on the first direction D1 side is referred to as the one-side spiral part 55, and the other on the first direction D1 side is referred to as the other-side spiral part 56. The one-side spiral portion 55 and the other-side spiral portion 56 are formed hollow inside the sound-insulating panel 20, and when sound waves are incident on the sound-insulating portion 10, the air inside each of them vibrates, generating Helmholtz resonance.

[0128] Neck portion 40 is formed along first direction D1 from approximately the center of first plate surface 21 to the other side of the center in first direction D1 of sound insulation board 20. As shown in Figures 26 and 27, neck portion 40 has one-side communicating portion 43 that communicates with one-side spiral portion 55, and another-side communicating portion 44 that communicates with other-side spiral portion 56 on the other side in first direction D1 from one-side communicating portion 43. Neck portion 40 has a constant opening area perpendicular to the direction in which the path extends from sound insulation opening 41 to other-side communicating portion 44, i.e., an opening area perpendicular to first direction D1.

[0129] 26, the one-side spiral portion 55 has a one-side outer wound portion 55a formed in a spiral shape along the outer shell of the sound insulation board 20, and a one-side inner wound portion 55b formed inside the one-side outer wound portion 55a. The one-side outer wound portion 55a and the one-side inner wound portion 55b are formed in positions where they overlap in the first direction D1.

[0130] The one-side outer wound portion 55a is formed in a left-handed spiral shape starting from the one-side communicating portion 43 of the neck portion 40 as a square shape when viewed from one side to the other side in the first direction D1. The one-side outer wound portion 55a has a one-side outer step portion 551 that changes the opening area perpendicular to the direction along the spiral shape of the one-side outer wound portion 55a in a stepped manner. The one-side outer step portion 551 is provided at the end of the one-side outer wound portion 55a opposite to the side communicating with the one-side communicating portion 43. The one-side outer step portion 551 has an opening area perpendicular to the direction along the spiral shape that gradually decreases from the starting end side to the terminal end side, specifically, decreases in a stepped manner. In other words, the inner diameter of the end portion on the terminal side of the one-side outer wound portion 55a decreases in a stepped manner from the starting end side to the terminal end side. In this embodiment, the inner diameter of one-side outer stepped portion 551 decreases in two steps from the starting end to the terminal end.

[0131] The shape of the one-side involuted portion 55b when viewed from one side to the other side in the first direction D1 is a right-handed spiral shape starting from the one-side communicating portion 43 of the neck portion 40, and is formed to draw a square. The one-side involuted portion 55b has a one-side inner staircase portion 552 that changes the opening area perpendicular to the direction along the spiral shape of the one-side involuted portion 55b in a stepped manner. The one-side inner staircase portion 552 is provided at the end of the one-side involuted portion 55b on the opposite side to the side communicating with the one-side communicating portion 43. The one-side inner staircase portion 552 has an opening area perpendicular to the direction along the spiral shape that gradually decreases from the starting end side to the terminal end side, specifically, decreases in a stepped manner. In other words, the inner diameter of the end portion on the terminal side of the one-side involuted portion 55b decreases in a stepped manner from the starting end side to the terminal end side. In the present embodiment, the inside diameter of the one-side inner stepped portion 552 decreases in two steps from the starting end side to the terminal end side.

[0132] 27, the other-side spiral portion 56 has an other-side outer wound portion 56a formed in a spiral shape along the outer shell of the sound insulation board 20, and an other-side inner wound portion 56b formed inside the other-side outer wound portion 56a. The other-side outer wound portion 56a and the other-side inner wound portion 56b are formed in positions where they overlap in the first direction D1.

[0133] The other side outer wound portion 56a has a right-handed spiral shape starting from the other side communicating portion 44 of the neck portion 40 as a starting point when viewed from one side to the other side in the first direction D1, and is formed to draw a square. The other side outer wound portion 56a has an other side outer step portion 561 that changes the opening area perpendicular to the direction along the spiral shape of the other side outer wound portion 56a in a stepped manner. The other side outer step portion 561 is provided at the end portion of the other side outer wound portion 56a opposite to the side communicating with the other side communicating portion 44. The other side outer step portion 561 has an opening area perpendicular to the direction along the spiral shape that gradually decreases from the starting end side to the terminal end side, specifically, decreases in a stepped manner. In other words, the inner diameter of the end portion on the terminal side of the other side outer wound portion 56a decreases in a stepped manner from the starting end side to the terminal end side. In the present embodiment, the inner diameter of the other-side outer stepped portion 561 decreases in two steps from the starting end to the terminal end.

[0134] The shape of the other side involuted portion 56b when viewed from one side to the other side in the first direction D1 is a right-handed spiral shape starting from the other side communicating portion 44 of the neck portion 40, and is formed to draw a square. The other side involuted portion 56b has an other side inner step portion 562 that changes the opening area perpendicular to the direction along the spiral shape of the other side involuted portion 56b in a stepped manner. The other side inner step portion 562 is provided at the end of the other side involuted portion 56b opposite to the side communicating with the other side communicating portion 44. The other side inner step portion 562 has an opening area perpendicular to the direction along the spiral shape that gradually decreases from the starting end side to the terminal end side, specifically, decreases in a stepped manner. In other words, the inner diameter of the end portion on the terminal side of the other side involuted portion 56b decreases in a stepped manner from the starting end side to the terminal end side. In the present embodiment, the other-side inner stepped portion 562 has an inner diameter that decreases in two steps from the starting end side to the terminal end side.

[0135] In this embodiment, the one-side outer wound portion 55a, the one-side inner wound portion 55b, the other-side outer wound portion 56a, and the other-side inner wound portion 56b function as bent portions. In this embodiment, the one-side outer stepped portion 551 functions as a changing portion that changes the inner diameter of the one-side outer wound portion 55a, and the one-side inner stepped portion 552 functions as a changing portion that changes the inner diameter of the one-side inner wound portion 55b. In addition, the other-side outer stepped portion 561 functions as a changing portion that changes the inner diameter of the other-side outer wound portion 56a, and the other-side inner stepped portion 562 functions as a changing portion that changes the inner diameter of the other-side inner wound portion 56b.

[0136] Here, the one-side outer winding portion 55a, the one-side inner winding portion 55b, the other-side outer winding portion 56a, and the other-side inner winding portion 56b of this embodiment are formed so that the resonance frequencies when the air inside each vibrates due to Helmholtz resonance are different. Specifically, the one-side outer winding portion 55a, the one-side inner winding portion 55b, the other-side outer winding portion 56a, and the other-side inner winding portion 56b have different lengths in the direction along the spiral shape from the end on the starting end side to the end on the terminal side. Here, the lengths in the direction along the spiral shape of the one-side outer winding portion 55a, the one-side inner winding portion 55b, the other-side outer winding portion 56a, and the other-side inner winding portion 56b are respectively referred to as the one-side outer winding length, the one-side inner winding length, the other-side outer winding length, and the other-side inner winding length. In this embodiment, the other-side outer winding length, the one-side outer winding length, the one-side inner winding length, and the other-side inner winding length are arranged in order of the length in the direction along the spiral shape.

[0137] In this way, by configuring the one-side outer winding length, one-side inner winding length, other-side outer winding length, and other-side inner winding length to be different from each other, the one-side outer winding portion 55a, one-side inner winding portion 55b, other-side outer winding portion 56a, and other-side inner winding portion 56b have different resonance frequencies in the sound insulating part 10. Therefore, the sound insulating part 10 can obtain sound insulating performance against sound waves in frequency bands near the resonance frequencies of the one-side outer winding portion 55a, one-side inner winding portion 55b, other-side outer winding portion 56a, and other-side inner winding portion 56b.

[0138] Furthermore, the one side outer wound portion 55a, the one side inward wound portion 55b, the other side outer wound portion 56a and the other side inward wound portion 56b each have stepped portions 551, 552, 561, 562 that change the opening area perpendicular to the direction along the spiral shape in a stepped manner.

[0139] For this reason, as described in the sixth embodiment, when sound waves are incident on each of the staircase portions 551, 552, 561, 562, the sound waves are reflected at each of the portions where the inner diameter of each of the staircase portions 551, 552, 561, 562 changes. Specifically, the sound waves incident on each of the staircase portions 551, 552, 561, 562 are reflected at each of the surfaces that form the steps and the surfaces at the terminal ends of each of the staircase portions 551, 552, 561, 562. As a result, the air inside the one-side outer winding portion 55a, the one-side inward winding portion 55b, the other-side outer winding portion 56a, and the other-side inward winding portion 56b resonates with frequencies including three resonant frequencies.

[0140] Therefore, sound insulation performance can be obtained against sound waves in frequency bands near three resonant frequencies among the sound waves incident on the one-side outer winding portion 55a, the one-side inner winding portion 55b, the other-side outer winding portion 56a, and the other-side inner winding portion 56b.

[0141] Here, the results of an experiment conducted to investigate the difference in transmission loss of the one-side outer wound portion 55a between the case where the one-side outer staircase portion 551 is provided on the one-side outer wound portion 55a and the case where the one-side outer staircase portion 551 is not provided will be described with reference to Figs. 28 and 29. Fig. 28 shows the end portion of the one-side outer wound portion 55a having the one-side outer staircase portion 551 and the end portion of the outer wound portion 55x of the comparative example not having the one-side outer staircase portion 551. The outer wound portion 55x of the comparative example has a constant opening area at the end portion on the end side perpendicular to the direction in which the path extends, that is, the opening area perpendicular to the direction along the spiral shape. The solid line shown in Fig. 29 indicates the transmission loss of the one-side outer wound portion 55a having the one-side outer staircase portion 551, and the dashed line shown in Fig. 29 indicates the transmission loss of the outer wound portion 55x of the comparative example not having the one-side outer staircase portion 551.

[0142] 29, one side outer wound portion 55a having one side outer step portion 551 can increase the transmission loss in three frequency bands. In contrast, the outer wound portion 55x of the comparative example not having one side outer step portion 551 can increase the transmission loss in only one frequency band.

[0143] 30 and 31 show the configuration diagram and the experimental results of an experiment carried out to evaluate the sound insulation structure 1 of this embodiment alone. In the configuration diagram of the experiment shown in FIG. 30, a sound generating source 210 that generates sound is arranged on one side of a hollow cylindrical circular tube 200, and a sound absorbing material 220 that absorbs the sound generated by the sound generating source 210 is arranged on the other side. Furthermore, between the sound generating source 210 and the sound absorbing material 220, either the sound insulation structure 1 of this embodiment or a comparison member 230 that is a plate material of the same shape and material as the sound insulation structure 1 and does not have the sound insulation part 10 is arranged. Then, sound pressure sensors 240 that measure sound pressure are arranged in front of and behind the sound insulation structure 1 or the comparison member 230.

[0144] FIG. 31 shows the difference in transmission loss between the sound-insulating structure 1 and the comparative member 230, calculated based on the difference in sound pressure before and after passing through the sound-insulating structure 1 or the comparative member 230, in such a configuration diagram.

[0145] As shown in FIG. 31, the sound-insulating structure 1 having the sound-insulating parts 10 was able to increase the transmission loss over an expanded range, compared to the comparative member 230 not having the sound-insulating parts 10.

[0146] 32 and 33 show a configuration diagram and experimental results of an experiment carried out to evaluate the sound insulation structure 1 of this embodiment attached to a speaker SP. Fig. 33 shows the sound pressures on the front and rear sides of the speaker SP measured by the sound pressure sensor 240 when a warning sound is generated from the speaker SP with the sound insulation structure 1 shown in Fig. 32 attached to the speaker SP. Fig. 33 also shows the sound pressures on the front and rear sides of the speaker SP measured by the sound pressure sensor 240 when a warning sound is generated from the speaker SP with a comparative member 230, which is a plate material having the same shape and material as the sound insulation structure 1 but does not have a sound insulation portion 10, attached to the speaker SP.

[0147] Line A in Fig. 33 indicates the sound pressure on the front side of the speaker SP when a warning sound is generated from the speaker SP with the sound-insulating structure 1 attached to the speaker SP, and line B indicates the sound pressure on the rear side of the speaker SP when a warning sound is generated from the speaker SP. Line C in Fig. 33 indicates the sound pressure on the front side of the speaker SP when a warning sound is generated from the speaker SP with the sound-insulating structure 1 not attached to the speaker SP, and line D indicates the sound pressure on the rear side of the speaker SP when a warning sound is generated from the speaker SP.

[0148] As shown in Fig. 33, when the sound insulation structure 1 is attached to the speaker SP, the sound pressure of the warning sound on the front side of the speaker SP can be increased over the entire measured frequency range compared to when the sound insulation structure 1 is not attached. And when the sound insulation structure 1 is attached to the speaker SP, the sound pressure of the warning sound on the rear side of the speaker SP can be reduced over the entire measured frequency range compared to when the sound insulation structure 1 is not attached. In other words, when the sound insulation structure 1 is attached to the speaker SP, the sound pressure difference between the warning sound on the front side and the rear side of the speaker SP can be increased over the entire measured frequency range compared to when the sound insulation structure 1 is not attached.

[0149] 34 and 35 show the configuration diagram and the experimental results of another experiment carried out to evaluate the sound insulation structure 1 of this embodiment attached to the speaker SP. FIG. 35 shows the sound pressure on the rear side of the speaker SP measured by the sound pressure sensor 240 when a warning sound is generated from the speaker SP in a state where the sound insulation structure 1 shown in FIG. 34 is attached to the speaker SP. Furthermore, FIG. 35 shows the sound pressure on the rear side measured by the sound pressure sensor 240 when a warning sound is generated from the speaker SP in a state where a comparative member 230, which is a plate material having the same shape and the same material as the sound insulation structure 1 shown in FIG. 34 and does not have the sound insulation part 10, is attached to the speaker SP. The solid line shown in FIG. 35 shows the sound pressure when the sound insulation structure 1 is attached to the speaker SP, and the dashed line shown in FIG. 35 shows the sound pressure when the comparative member 230 is attached to the speaker SP.

[0150] As shown in Figure 35, when the sound-insulating structure 1 was attached to the speaker SP, the sound pressure of the warning sound on the rear side of the speaker SP was reduced across the entire measured frequency range compared to when the comparative member 230 was attached to the speaker SP.

[0151] As described above, according to the sound-insulating structure 1 of this embodiment, the sound-insulating part 10 can obtain sound-insulating performance against sound waves in frequency bands near the resonant frequencies of the one-side outer winding part 55a, the one-side inner winding part 55b, the other-side outer winding part 56a, and the other-side inner winding part 56b. Furthermore, due to the reflection of sound waves from the step surfaces and the terminal surface of each of the step portions 551, 552, 561, and 562 of the one-side outer winding part 55a, the one-side inner winding part 55b, the other-side outer winding part 56a, and the other-side inner winding part 56b, sound-insulating performance can be obtained against sound waves in frequency bands near the three resonant frequencies among the sound waves incident on each of the one-side outer winding part 55a, the one-side inner winding part 55b, the other-side outer winding part 56a, and the other-side inner winding part 56b.

[0152] This allows the speaker SP to provide a wide frequency band of sound insulation performance against unwanted warning sounds directed toward the rear of the vehicle, thereby improving the ride comfort of passengers in the vehicle cabin.

[0153] Eighth embodiment Next, an eighth embodiment will be described with reference to Figs. 36 and 37. In this embodiment, the shape of a part of the resonator unit 30 is different from that of the first embodiment. The rest is the same as the first embodiment. Therefore, in this embodiment, the parts different from the first embodiment will be mainly described, and the description of the parts similar to the first embodiment may be omitted.

[0154] As shown in Figs. 36 and 37, the resonance unit 30 has an uneven portion 71 that changes the opening area perpendicular to the direction along the spiral shape of the spiral unit 50 in an uneven shape. The uneven portion 71 is provided at the end of the terminal side of the spiral unit 50 and is formed in an uneven shape. The uneven portion 71 is formed in an uneven shape on the resonance surface 53 of the spiral unit 50. Specifically, the uneven portion 71 is formed in a so-called wave shape, in other words, a sawtooth blade shape. The uneven portion 71 has a space between each uneven portion that is sufficiently small compared to the wavelength of the sound wave incident on the sound insulation unit 10. The uneven portion 71 can be formed by forming the resonance surface 53 roughly, for example by setting the processing accuracy of the resonance surface 53 to be relatively low.

[0155] As a result, in the direction along the spiral shape of the spiral portion 50, the opening area perpendicular to the direction along the spiral shape varies in size according to the shape of the uneven portion 71. In other words, the inner diameter of the second end 52 of the spiral portion 50 varies continuously. In this embodiment, the uneven portion 71 functions as a varying portion that changes the inner diameter of the spiral portion 50.

[0156] The operation of sound insulation part 10 when uneven part 71 is thus formed in spiral part 50 will be described. When a sound wave is incident on sound insulation part 10 having uneven part 71, this sound wave is propagated into the inside of spiral part 50 via neck part 40. Then, the sound wave propagated into the inside of spiral part 50 is reflected by resonance surface 53 of spiral part 50.

[0157] Here, sound waves propagating to the uneven portion 71 are scattered by being reflected on the surface of the uneven portion 71. Therefore, in the uneven portion 71, the scattered sound waves cause the air inside the resonator 30 to resonate with a plurality of resonant frequencies. Therefore, it is possible to obtain sound insulation performance against sound waves in frequency bands near the plurality of resonant frequencies among the sound waves incident on the sound-insulating structure 1.

[0158] The other configurations are the same as those of the first embodiment. The sound insulating portion 10 of this embodiment can obtain the same effects as those of the first embodiment, which are achieved by a configuration similar to or equivalent to those of the first embodiment.

[0159] Ninth embodiment Next, the ninth embodiment will be described with reference to Fig. 38. This embodiment differs from the eighth embodiment in that the uneven portion 71 is replaced with a plurality of groove portions 72 as a varying portion that changes the inner diameter of the spiral portion 50. The rest is the same as the eighth embodiment. Therefore, in this embodiment, the portions different from the eighth embodiment will be mainly described, and the description of the portions similar to the eighth embodiment may be omitted.

[0160] As shown in FIG. 38, the resonance unit 30 has a plurality of grooves 72 that change the opening area perpendicular to the direction along the spiral shape of the spiral unit 50. A plurality of grooves 72 are provided at the end of the spiral unit 50 on the terminal side. Specifically, the plurality of grooves 72 are formed side by side at a predetermined interval in the direction along the spiral shape. The grooves 72 are formed recessed with respect to the resonance surface 53 of the spiral unit 50. The depth and width of each of the plurality of grooves 72 are appropriately set, and include grooves 72 whose depth and width are equal and grooves 72 whose depth and width are different from each other. In addition, the depth and width of each of the plurality of grooves 72 are sufficiently large with respect to the wavelength of the sound wave incident on the sound insulation unit 10. The shape of the grooves 72 may be a cylindrical shape, a rectangular parallelepiped shape, or the like.

[0161] As a result, in the direction along the spiral shape of the spiral portion 50, the opening area perpendicular to the direction along the spiral shape changes between a portion where the groove portion 72 is formed and a portion where the groove portion 72 is not formed. In other words, in the spiral portion 50, the opening area of ​​the portion where the groove portion 72 is formed is larger than the opening area of ​​the portion where the groove portion 72 is not formed. In this embodiment, the groove portion 72 functions as a changing portion that changes the inner diameter of the spiral portion 50.

[0162] The operation of sound insulation 10 when grooves 72 are thus formed in spiral portion 50 will be described. When sound waves are incident on sound insulation 10 having grooves 72, the sound waves are propagated into the inside of spiral portion 50 via neck portion 40. The sound waves propagated into the inside of spiral portion 50 enter each of the multiple grooves 72 provided in spiral portion 50 and are reflected by these multiple grooves 72.

[0163] Here, a plurality of grooves 72 are formed side by side at a predetermined interval in the direction along the spiral shape. Therefore, the distance from the first end 51 to each of the plurality of grooves 72 varies depending on the position of each groove 72. Therefore, the air inside the resonator 30 resonates with a plurality of resonant frequencies in response to the sound waves reflected by each groove 72. Therefore, sound insulation performance can be obtained against sound waves in frequency bands near the plurality of resonant frequencies among the sound waves incident on the sound insulation structure 1.

[0164] The depth and width of each of the plurality of grooves 72 are appropriately set according to a specific frequency band for obtaining the necessary sound insulation performance in the sound insulation part 10.

[0165] The other configuration is the same as that of the eighth embodiment. The sound insulating portion 10 of this embodiment can obtain the same effects as those of the eighth embodiment, which are achieved by a configuration similar to or equivalent to that of the eighth embodiment.

[0166] Tenth embodiment Next, the tenth embodiment will be described with reference to Fig. 39. This embodiment differs from the eighth embodiment in that the uneven portion 71 is replaced with a plurality of protrusions 73 as a varying portion that changes the inner diameter of the spiral portion 50. The rest is the same as the eighth embodiment. Therefore, in this embodiment, the portions different from the eighth embodiment will be mainly described, and the description of the portions similar to the eighth embodiment may be omitted.

[0167] As shown in FIG. 39, the resonator 30 has a plurality of protrusions 73 that change the opening area perpendicular to the direction along the spiral shape of the spiral part 50. A plurality of protrusions 73 are provided at the end of the terminal side of the spiral part 50. Specifically, the plurality of protrusions 73 are formed side by side at a predetermined interval in the direction along the spiral shape. The protrusions 73 are formed protruding from the resonator surface 53 of the spiral part 50. The height and width of each of the plurality of protrusions 73 are appropriately set, and include protrusions 73 having the same height and width and protrusions 73 having different heights and widths. In addition, the height and width of each of the plurality of protrusions 73 are sufficiently large with respect to the wavelength of the sound wave incident on the sound insulation part 10. The shape of the protrusions 73 may be a cylindrical shape, a rectangular parallelepiped shape, or the like.

[0168] As a result, in the direction along the spiral shape of the spiral portion 50, the opening area perpendicular to the direction along the spiral shape changes between a portion where the protruding portion 73 is formed and a portion where the protruding portion 73 is not formed. In other words, in the spiral portion 50, the opening area of ​​the portion where the protruding portion 73 is formed is smaller than the opening area of ​​the portion where the protruding portion 73 is not formed. In this embodiment, the protruding portion 73 functions as a changing portion that changes the inner diameter of the spiral portion 50.

[0169] The operation of sound insulation part 10 when protrusions 73 are thus formed on spiral part 50 will be described. When sound waves are incident on sound insulation part 10 having protrusions 73, the sound waves are propagated into the inside of spiral part 50 via neck part 40. Then, the sound waves propagated into the inside of spiral part 50 are reflected by the multiple protrusions 73 provided on spiral part 50.

[0170] Here, the protrusions 73 are formed in a line at a predetermined interval in the direction along the spiral shape. Therefore, the distance from the first end 51 to each of the protrusions 73 varies depending on the position of each protrusion 73. Therefore, the air inside the resonator 30 resonates with a plurality of resonant frequencies in response to the sound waves reflected by each protrusion 73. Therefore, sound insulation performance can be obtained against sound waves in frequency bands near the plurality of resonant frequencies among the sound waves incident on the sound insulation structure 1.

[0171] The height and width of each of the plurality of protrusions 73 are appropriately set according to a specific frequency band for obtaining the necessary sound insulation performance in the sound insulation part 10.

[0172] The other configuration is the same as that of the eighth embodiment. The sound insulating portion 10 of this embodiment can obtain the same effects as those of the eighth embodiment, which are achieved by a configuration similar to or equivalent to that of the eighth embodiment.

[0173] (Modification of the tenth embodiment) In the above-described tenth embodiment, an example in which the spiral portion 50 is provided with the plurality of protruding portions 73 has been described, but the present invention is not limited to this.

[0174] For example, the spiral portion 50 may be configured to further include the groove portion 72 described in the ninth embodiment in addition to the protrusion portion 73.

[0175] Eleventh embodiment Next, an eleventh embodiment will be described with reference to Figs. 40 to 43. This embodiment differs from the first embodiment in that the end on the terminal side of the spiral portion 50 is open, and the sound insulating portion 10 is provided with a blocking portion 80 that blocks the opening on the end on the terminal side. Other than this, this embodiment is similar to the first embodiment. Therefore, in this embodiment, the parts that differ from the first embodiment will be mainly described, and a description of the parts that are similar to the first embodiment may be omitted.

[0176] 40 and 41, in the spiral portion 50 of this embodiment, a second end 52, which is opposite to a first end 51 communicating with the communicating portion 42 of the neck portion 40, opens at a second plate surface 22 on the other side of the sound insulation panel 20 in the first direction D1. The second end 52 of the spiral portion 50 extends along the first direction D1 to the second plate surface 22 of the sound insulation panel 20, and has a spiral opening 45 at the second plate surface 22 that communicates with the outside of the sound insulation panel 20. The spiral opening 45 in this embodiment functions as a bent opening.

[0177] And, sound insulation part 10 includes a closing part 80 that closes spiral opening 45. Closing part 80 has an insertion part 81 that is inserted into spiral part 50, and a support part 82 that communicates with said insertion part 81, as shown in FIG.

[0178] Insertion section 81 is cylindrical, and has an outer diameter slightly smaller than the inner diameter of spiral opening 45, so that insertion section 81 can be inserted into spiral section 50 from spiral opening 45. Support section 82 has an outer diameter sufficiently larger than the inner diameter of spiral opening 45, so that insertion section 82 cannot be inserted into spiral section 50 from spiral opening 45. When insertion section 81 is inserted into spiral section 50, which is within resonance space S, from spiral opening 45, second end 52 of spiral section 50 is closed. Closing second end 52 of spiral section 50 defines a spiral length, which is a length in a direction along the spiral shape of spiral section 50, and thereby defines a spiral volume, which is a volume of the space formed by spiral section 50.

[0179] Here, the axial size of the cylindrical insertion portion 81 is defined as an insertion length LS. As shown in Fig. 41 and Fig. 42, the sound insulating part 10 of the present embodiment includes a first blocking part 80a and a second blocking part 80b having different insertion lengths LS. As shown in Fig. 41 and Fig. 42, the second blocking part 80b is formed with a larger insertion length LS than the first blocking part 80a.

[0180] Therefore, the spiral length of the spiral portion 50 changes depending on whether the first occluding portion 80a or the second occluding portion 80b is inserted, and the spiral volume also changes accordingly. Specifically, when the first occluding portion 80a is inserted into the spiral portion 50, the spiral length is larger and the spiral volume is larger than when the second occluding portion 80b is inserted. In contrast, when the second occluding portion 80b is inserted into the spiral portion 50, the spiral length is smaller and the spiral volume is smaller than when the first occluding portion 80a is inserted. The first occluding portion 80a and the second occluding portion 80b in this embodiment function as bend adjustment portions that adjust the spiral volume.

[0181] Next, the operation of the sound insulation unit 10 of this embodiment in which the spiral unit 50 thus includes the first blocking portion 80a and the second blocking portion 80b will be described. When a sound wave is incident on the sound insulation unit 10 in which the second end 52 side of the spiral unit 50 is blocked by the first blocking portion 80a or the second blocking portion 80b, the sound wave is propagated into the inside of the spiral unit 50 via the neck portion 40. Then, the sound wave propagated into the inside of the spiral unit 50 is reflected by the insertion portion 81 of the first blocking portion 80a or the second blocking portion 80b.

[0182] Here, the position at which the sound waves are reflected by the insertion portion 81 changes depending on the position of the insertion portion 81. For example, when the first blocking portion 80a is inserted into the spiral portion 50, the sound waves reflected by the insertion portion 81 are reflected at a position farther from the first end 51 than when the second blocking portion 80b is inserted. In contrast, when the second blocking portion 80b is inserted into the spiral portion 50, the sound waves reflected by the insertion portion 81 are reflected at a position closer to the first end 51 than when the first blocking portion 80a is inserted. For this reason, the air inside the resonator 30 resonates at two different resonant frequencies depending on the blocking portion 80 inserted into the spiral portion 50.

[0183] Therefore, among the sound waves incident on the sound-insulating structure 1, sound-insulating performance against sound waves in frequency bands near the two resonant frequencies can be obtained.

[0184] The sound insulation performance of the sound insulation part 10 of this embodiment configured as described above is shown in Fig. 43. As shown in Fig. 43, the sound insulation part 10 of this embodiment has outstanding sound insulation performance in two different frequency bands. Specifically, when the first blocking part 80a is inserted, the sound insulation part 10 exhibits sound insulation performance in the lower frequency band of two frequencies in which the sound insulation performance is exhibited. Then, when the second blocking part 80b is inserted, the sound insulation part 10 exhibits sound insulation performance in the higher frequency band of two frequencies in which the sound insulation performance is exhibited.

[0185] In addition, the solid line shown in Figure 43 indicates the transmission loss of the sound-insulating section 10 when the first blocking section 80a is inserted into the spiral section 50, and the dashed line indicates the transmission loss of the sound-insulating section 10 when the second blocking section 80b is inserted into the spiral section 50.

[0186] The insertion length LS of each of the first blocking portion 80a and the second blocking portion 80b is appropriately set according to a specific frequency band for obtaining the necessary sound insulation performance in the sound insulation portion 10.

[0187] The other configurations are the same as those of the first embodiment. The sound insulating portion 10 of this embodiment can obtain the same effects as those of the first embodiment, which are achieved by a configuration similar to or equivalent to those of the first embodiment.

[0188] Moreover, the spiral portion 50 of the present embodiment has a first closing portion 80a and a second closing portion 80b that close the spiral opening 45 at a second end 52 opposite to a first end 51 side that communicates with the sound-insulating opening 41. The spiral volume of the spiral portion 50 can be adjusted by the first closing portion 80a and the second closing portion 80b.

[0189] According to this, the first closing portion 80a and the second closing portion 80b adjust the volute volume, thereby changing the resonance frequency of the resonance portion 30. Therefore, it is possible to obtain sound insulation performance against sound waves in frequency bands near a plurality of resonance frequencies among sound waves incident on the sound-insulating structure 1.

[0190] Furthermore, according to the above embodiment, the following effects can be obtained.

[0191] (1) In the above embodiment, the spiral portion 50 has a spiral opening 45 at the second end 52 that communicates with the outside of the sound insulation panel 20 and can be closed by a closing portion 80. The closing portion 80 includes a first closing portion 80a and a second closing portion 80b that have different insertion lengths LS, and the spiral volume is adjusted according to the closing portion 80 inserted from the spiral opening 45.

[0192] According to this, by switching the closing portion 80 inserted from the volute opening 45, the volute volume can be easily adjusted.

[0193] (Modification of the eleventh embodiment) In the above-described eleventh embodiment, an example has been described in which the blocking portion 80 includes the first blocking portion 80a and the second blocking portion 80b that have different insertion lengths LS, but the present invention is not limited to this.

[0194] For example, the sound insulating section 10 may be configured to include three or more blocking sections 80 with different insertion lengths LS.

[0195] Twelfth embodiment Next, the twelfth embodiment will be described with reference to Figs. 44 to 45. This embodiment differs from the eleventh embodiment in that a thread groove 74 is formed in the resonance surface 53, and the closure portion 80 inserted into the spiral opening 45 is replaced with a screw 75 fastened to the thread groove 74. The rest is the same as the eleventh embodiment. Therefore, in this embodiment, the parts different from the eleventh embodiment will be mainly described, and the description of the parts similar to the eleventh embodiment may be omitted.

[0196] 44 , in the spiral portion 50 of the present embodiment, a thread groove 74 communicating with the spiral opening 45 is formed on the second end 52 side of the resonance surface 53, which is opposite to the first end 51 side communicating with the communicating portion 42 of the neck portion 40. The thread groove 74 is formed in an uneven shape on the resonance surface 53 of the spiral portion 50. In the present embodiment, the thread groove 74 functions as a changing portion that changes the inner diameter of the spiral portion 50.

[0197] The sound insulation part 10 includes one screw 75 that can be fastened to the screw groove 74 and closes the spiral opening 45. As shown in Fig. 44, the screw 75 has a fastening part 751 that can be fastened to the screw groove 74, and a screw head 752 that is continuous with the fastening part 751.

[0198] Then, the second end 52 side of the spiral portion 50 is closed by inserting the fastening portion 751 from the spiral opening 45 into the inside of the spiral portion 50, which is within the resonance space S, and fastening it to the thread groove 74. By closing the second end 52 side of the spiral portion 50, the spiral length, which is the length in the direction along the spiral shape of the spiral portion 50, is defined, and thereby the spiral volume, which is the volume of the space formed by the spiral portion 50, is defined.

[0199] As shown in Figures 44 and 45, in sound insulation part 10 of this embodiment, the spiral length changes according to the tightening position of screw 75 into screw groove 74, and the spiral volume changes accordingly. Specifically, the spiral length increases as the tightening position of screw 75 becomes shallower, and the spiral volume also increases. In contrast, the spiral length decreases as the tightening position of screw 75 becomes deeper, and the spiral volume also decreases. Screw 75 of this embodiment functions as a bend adjustment part that adjusts the spiral volume.

[0200] Next, a description will be given of the operation of sound insulation part 10 of this embodiment in which screw groove 74 is formed in spiral part 50 and screw 75 is provided that can be fastened to screw groove 74. When sound waves are incident on sound insulation part 10 in which second end 52 side of spiral part 50 is closed by screw 75, the sound waves are propagated into the inside of spiral part 50 via neck part 40. Then, the sound waves propagated into the inside of spiral part 50 are reflected by fastening part 751 of screw 75.

[0201] Here, the position at which the sound waves are reflected by the fastening portion 751 changes depending on the fastening position of the screw 75. Therefore, the resonant frequency of the air inside the resonating portion 30 when resonating changes depending on the fastening position of the screw 75 inserted into the spiral portion 50. Therefore, sound insulation performance can be obtained for sound waves in a frequency band near the resonant frequency that changes depending on the fastening position of the screw 75, among the sound waves incident on the sound-insulating structure 1. The fastening position of the screw 75 is appropriately set depending on the specific frequency band for obtaining the sound insulation performance required for the sound-insulating portion 10.

[0202] Furthermore, since the resonant frequency of the resonating section 30 can be adjusted depending on the tightening position of the screw 75, the resonant frequency of the resonating section 30 can be adjusted more easily than in the configuration in which the blocking section 80 is switched as shown in the eleventh embodiment.

[0203] The other configuration is the same as that of the 11th embodiment. The sound insulating portion 10 of this embodiment can obtain the same effects as those of the 11th embodiment, which are achieved by a configuration similar to or equivalent to that of the 11th embodiment.

[0204] Thirteenth embodiment Next, the thirteenth embodiment will be described with reference to Figs. 46 to 47. This embodiment differs from the twelfth embodiment in that the volute volume is adjusted by switching the inserted screw 75. The rest is similar to the twelfth embodiment. Therefore, in this embodiment, the differences from the twelfth embodiment will be mainly described, and descriptions of the similarities between the twelfth embodiment and the twelfth embodiment may be omitted.

[0205] 46 and 47, sound insulation part 10 of the present embodiment includes two screws 75 having fastening parts 751 of different lengths. Sound insulation part 10 is configured to be able to adjust the distance from sound insulation opening 41 to fastening part 751 by switching screws 75 having fastening parts 751 of different lengths to be fastened to thread groove 74, thereby adjusting the volute volume. Screw 75 of the present embodiment functions as a bend adjustment part that adjusts the volute volume.

[0206] According to this, by adjusting the distance from the sound-insulating opening 41 to the fastening portion 751 by switching the screw 75, it is possible to change the spiral volume and thereby change the resonance frequency of the resonating portion 30. Therefore, it is possible to obtain sound insulation performance against sound waves in frequency bands near a plurality of resonance frequencies among sound waves incident on the sound-insulating structure 1.

[0207] (Other embodiments) Representative embodiments of the present disclosure have been described above, but the present disclosure is not limited to the above-described embodiments and can be modified in various ways, for example, as described below.

[0208] In the above-described embodiment, an example has been described in which the cross-sectional shape perpendicular to the direction in which the resonator unit 30 extends from one end to the other end is circular or rectangular, but this is not limited to this.

[0209] The cross-sectional shape perpendicular to the direction extending from one end of the resonator unit 30 to the other end is not limited, and may be any suitable shape such as a rounded rectangle, an oval, or a polygon.

[0210] In the above embodiment, an example has been described in which the sound-insulating opening 41 and the spiral opening 45 are formed in the plate surface on one side or the other side in the first direction D1 of the sound-insulating plate 20, but the present invention is not limited to this.

[0211] For example, the sound-insulating opening 41 and the spiral opening 45 may be formed on a side surface of the sound-insulating board 20 in the second direction D2 or the third direction D3.

[0212] In the above embodiment, an example in which the resonance space S is filled with air has been described, but the present invention is not limited to this.

[0213] For example, the resonance space S may be filled with a gas other than air, such as gas, or may be filled with a liquid.

[0214] In the above embodiment, an example has been described in which the spiral portion 50, the first spiral portion 50a, the second spiral portion 50b, the one-side spiral portion 55, and the other-side spiral portion 56 in the resonance portion 30 are formed in a spiral shape, but this is not limiting. The shape of the space for generating Helmholtz resonance in the resonance portion 30 is not limited to a spiral shape as long as it is a curved shape, and a circular shape, a polygonal shape, a U-shape, or the like can be appropriately adopted.

[0215] In the above-described embodiments, it goes without saying that the elements constituting the embodiments are not necessarily essential, except in cases where it is particularly expressly stated that they are essential or where they are clearly considered to be essential in principle.

[0216] In the above-described embodiments, when numerical values ​​such as the number, values, amounts, ranges, etc. of components of the embodiments are mentioned, they are not limited to the specific numbers unless it is specifically stated as required or unless it is clearly limited to a specific number in principle.

[0217] In the above-described embodiments, when referring to the shapes, positional relationships, etc. of components, etc., there is no limitation to those shapes, positional relationships, etc., unless specifically stated or in principle limited to a specific shape, positional relationship, etc.

[0218] (In view of the present disclosure) The present disclosure described above can be understood from the following viewpoints, for example.

[0219] [First viewpoint] A sound-insulating part, A plate-shaped sound-proofing plate material (20) forming an outer shell; a hollow tubular resonator (30, 30a, 30b) formed inside the sound-proofing board and having a sound-proofing opening (41) at one end thereof communicating with the outside of the sound-proofing board; The resonator portion forms a resonator space (S) that communicates with the sound-insulating opening, and has a bent portion (50, 50a, 50b, 55, 56) that is bent.

[0220] [Second viewpoint] The sound insulating section according to the first aspect, wherein the resonance section has a resonance space filled with air.

[0221] [Third Perspective] The soundproofing section according to the first or second aspect, wherein the resonating section has a circular cross-sectional shape perpendicular to a direction extending from the one end to the other end.

[0222] [Fourth viewpoint] The soundproofing section according to the first or second aspect, wherein the resonating section has a rectangular cross-sectional shape perpendicular to a direction extending from the one end to the other end.

[0223] [Fifth viewpoint] The sound insulating section according to any one of the first to fourth aspects, wherein the bent portion is formed in a spiral shape.

[0224] [Sixth viewpoint] The resonating unit is provided in plurality, The sound insulating section according to any one of the first to fifth aspects, wherein the bent portion is formed in each of a plurality of the resonating sections.

[0225] [Seventh viewpoint] The sound-proof section according to a sixth aspect, wherein the plurality of bent sections have resonance spaces each having a different volume.

[0226] [Eighth viewpoint] When the plate thickness direction of the sound-proof plate is defined as a first direction, The sound-proofing section according to the sixth or seventh aspect, wherein the plurality of bent portions are arranged side by side at predetermined intervals in the first direction.

[0227] [Ninth viewpoint] When the plate thickness direction of the sound-proof plate is defined as a first direction, The sound insulating section according to the sixth or seventh aspect, wherein the plurality of bent portions are provided so as to overlap each other in the first direction.

[0228] [10th viewpoint] The sound-proofing section according to a ninth aspect, wherein the shapes of the plurality of bent portions perpendicular to the first direction are point-symmetrical with respect to a predetermined reference point, and the bent portions are disposed in the gaps between each other.

[0229] [Eleventh viewpoint] The bent portion has a resonance surface (53) that surrounds the resonance space and extends in a tubular shape, The sound insulating portion according to the first aspect, wherein the resonance surface has a change portion (54, 551, 552, 561, 562, 71, 72, 73, 74) that changes an inner diameter of the bent portion.

[0230] [12th viewpoint] The sound-proofing portion according to an eleventh aspect, wherein the changing portion changes the inner diameter stepwise.

[0231] [13th viewpoint] The sound-proofing portion according to the eleventh or twelfth aspect, wherein the change portion includes a portion formed in an uneven shape.

[0232] [14th viewpoint] The sound insulating section according to any one of the eleventh to thirteenth aspects, wherein the change portion includes a portion formed to be recessed with respect to the resonance surface.

[0233] [15th viewpoint] The sound insulating section according to any one of the eleventh to fourteenth aspects, wherein the change portion includes a portion formed to protrude from the resonance surface.

[0234] [16th viewpoint] The sound insulating portion according to any one of the eleventh to fifteenth aspects, wherein the bent portion has a bend adjustment portion (75, 80) that adjusts the volume of a space formed in the bent portion.

[0235] [17th viewpoint] The bent portion has a bent opening (45) communicating with the outside of the sound-insulating board material on the side opposite to the side communicating with the sound-insulating opening, The bend adjustment portion has an insertion portion (751, 81) that closes the bend opening by being inserted into the bend opening, and is composed of a plurality of closing portions (75, 80) whose lengths in the insertion direction are different from each other, and the sound-proofing portion described in the sixteenth aspect adjusts the volume of the space formed in the bend depending on the closing portion inserted from the bend opening.

[0236] [18th viewpoint] The bent portion has a bent opening (45) communicating with the outside of the sound-insulating plate material on the side opposite to the side communicating with the sound-insulating opening, and a screw groove (74) is formed in a portion of the resonance surface communicating with the bent opening, The sound-proofing section described in the sixteenth aspect, wherein the bend adjustment section is constituted by a single screw (75) that can be tightened into the screw groove, and the volume of the space formed in the bend section is adjusted depending on the tightening position of the screw into the screw groove.

[0237] [19th viewpoint] The sound-proofing section according to any one of the first to eighteenth aspects, comprising an energy reducing section (60, 65) provided within the resonance space and reducing energy of sound waves propagating within the resonance space.

[0238] [20th viewpoint] The sound insulating portion according to a nineteenth aspect, wherein the energy reducing portion includes a sound absorbing material (60) that absorbs sound waves propagating within the resonance space.

[0239] [21st viewpoint] The sound insulating portion according to a nineteenth aspect, wherein the energy reducing portion includes a viscoelastic body (65) that is viscoelastically deformed by sound waves propagating within the resonance space.

[0240] [22nd viewpoint] The sound insulation part according to any one of the first to twenty-first aspects, wherein the sound insulation part is attached to a housing (S10) of a speaker (SP) mounted in a vehicle. [Explanation of symbols]

[0241] 20 Soundproofing boards 30 Resonance part 41 Soundproofing openings 50, 50a, 50b, 55, 56 bent part

Claims

1. In the case of sound insulation, A plate-shaped sound-proofing plate material (20) forming an outer shell; a hollow tubular resonator (30, 30a, 30b) formed inside the sound-proofing board and having a sound-proofing opening (41) at one end thereof communicating with the outside of the sound-proofing board; The resonator portion forms a resonator space (S) that communicates with the sound-insulating opening, and has a bent portion (50, 50a, 50b, 55, 56) that is formed by bending.

2. The sound insulating section according to claim 1 , wherein the resonator has a resonant space filled with air.

3. The sound insulation section according to claim 1 , wherein the resonating section has a circular cross section perpendicular to a direction extending from the one end to the other end.

4. The sound insulation section according to claim 1 , wherein the resonating section has a rectangular cross section perpendicular to a direction in which the resonating section extends from the one end to the other end.

5. The sound insulating portion according to claim 1 , wherein the bent portion is formed in a spiral shape.

6. The resonating unit is provided in plurality, The sound insulation section according to claim 1 , wherein the bent portion is formed in each of the plurality of resonating sections.

7. The sound insulating section according to claim 6 , wherein the plurality of bent sections have resonance spaces each having a different volume.

8. When the plate thickness direction of the sound-proof plate is defined as a first direction, The sound insulation section according to claim 6 or 7, wherein the plurality of bent portions are arranged side by side at predetermined intervals in the first direction.

9. When the plate thickness direction of the sound-proof plate is defined as a first direction, The sound insulation section according to claim 6 or 7, wherein the plurality of bent portions are provided so as to overlap each other in the first direction.

10. The sound-proof section according to claim 9 , wherein the plurality of bent portions have shapes perpendicular to the first direction that are point-symmetric with respect to a predetermined reference point, and are disposed in spaces between each other.

11. The bent portion has a resonance surface (53) that surrounds the resonance space and extends in a tubular shape, 2. The sound insulating portion according to claim 1, wherein the resonance surface has a change portion (54, 551, 552, 561, 562, 71, 72, 73, 74) that changes an inner diameter of the bent portion.

12. The sound insulating portion according to claim 11 , wherein the changing portion changes the inner diameter in a stepwise manner.

13. The sound insulating section according to claim 11 , wherein the change portion includes a portion formed in an uneven shape.

14. The sound insulating section according to claim 11 , wherein the change portion includes a portion formed to be recessed from the resonance surface.

15. The sound insulating section according to claim 11 , wherein the change portion includes a portion formed to protrude from the resonance surface.

16. The sound insulating portion according to claim 11, wherein the bent portion has a bend adjustment portion (75, 80) for adjusting the volume of the space formed in the bent portion.

17. The bent portion has a bent opening (45) communicating with the outside of the sound-insulating plate material on the side opposite to the side communicating with the sound-insulating opening, The sound-proofing section according to claim 16, wherein the bend adjustment section has an insertion section (751, 81) that closes the bend opening by being inserted into the bend opening, and is composed of a plurality of closing sections (75, 80) whose lengths in the insertion direction are different from each other, and adjusts the volume of the space formed in the bend depending on the closing section inserted from the bend opening.

18. The bent portion has a bent opening (45) communicating with the outside of the sound-insulating plate material on the side opposite to the side communicating with the sound-insulating opening, and a screw groove (74) is formed in a portion of the resonance surface communicating with the bent opening, The sound-proofing section according to claim 16, wherein the bend adjustment section is constituted by a single screw (75) that can be tightened into the screw groove, and the volume of the space formed in the bend section is adjusted depending on the tightening position of the screw into the screw groove.

19. 2. The sound insulating section according to claim 1, further comprising an energy reducing section (60, 65) provided within the resonance space and configured to reduce energy of sound waves propagating within the resonance space.

20. 20. The sound insulation section according to claim 19, wherein the energy reduction section includes a sound absorbing material (60) that absorbs sound waves propagating within the resonant space.

21. The sound insulating portion according to claim 19, wherein the energy reducing portion includes a viscoelastic body (65) that is viscoelastically deformed by sound waves propagating within the resonance space.

22. 2. The sound insulating portion according to claim 1, wherein the sound insulating portion is attached to a housing (S10) of a speaker (SP) mounted in a vehicle.

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