Sound insulation structure

Abstract

To provide a sound insulation structure that can be easily and stably placed on a curved or uneven mounting surface, is thin and lightweight, and has good sound insulation properties.SOLUTION: A sound insulation structure 1 includes a hollow frame structure 6 and a weight portion 4 located inside a hollow portion 5 of the frame structure 6. The frame structure 6 comprises a base 2 and a peripheral wall portion 3. The weight portion 4 is attached to the base 2 of the frame structure 6 and extends toward an opening portion 5a, and is surrounded with the base 2 and the peripheral wall portion 3, except for a position opposite the opening portion 5a. Height H1 of the peripheral wall portion 3 is greater than height H2 of the weight portion 4. The weight portion 4 constitutes a spring mass resonator having a spring section 4a, which is located on a side of the base 2 and has elasticity, and a mass section 4b, which is located on the opposite side of the base 2 and has a greater mass than the spring section 4a. In a frequency band between 100 Hz and 2 kHz, there is a region where effective mass density is negative and an effective volume modulus is positive. A difference between the highest and lowest frequencies of the region is 200 Hz or more.SELECTED DRAWING: Figure 1

Description

[Technical field]

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

[0002] In recent years, in the rooms of buildings such as apartment buildings, office buildings, and hotels, outdoor noise from automobiles, trains, airplanes, ships, etc. outside the building, and equipment noise and human voices generated outside the room inside the building are required to be blocked, and quietness suitable for the use of the room is required. In addition, in the interior of vehicles such as automobiles, trains, airplanes, and ships, it is desired to reduce noise in order to block wind noise and engine noise and provide a quiet and comfortable space for the occupants. Therefore, there is a demand for means for blocking the propagation of noise and vibration from the outside to the inside of a building or vehicle, and also for the propagation of noise and vibration from the outside to the inside of a building or vehicle, that is, a member with high sound insulation properties. In recent years, there is a demand for lightweight sound insulation members in buildings due to the increase in height, and there is also a demand for lightweight sound insulation members in vehicles to improve energy efficiency. Examples of sound insulation structures forming soundproof walls in vehicles and buildings are disclosed in Patent Documents 1 to 6.

[0003] The invention described in Patent Document 1 comprises an acoustic damping panel comprising a rigid frame divided into a number of individual cells, a sheet of flexible material, and a number of weights, each weight being fixed to the sheet of flexible material such that each cell is provided with its own weight, and the attenuated sound is controlled by appropriate selection of the mass of the weights.

[0004] In the invention described in Patent Document 2, in a soundproofing material having an elastic sheet and a support part that holds the sheet and divides the sheet into partitions, the relationship between the rigidity of the sheet in the partitions and the areal density of the sheet is specified.

[0005] The soundproofing material of the invention described in Patent Document 3 is a structure comprising a flat substrate portion and a plurality of resonating portions connected to the substrate portion and having a predetermined resonant frequency, each of the plurality of resonating portions having a weight portion and a connecting portion connecting the weight portion to the substrate portion, and configured such that in a projection view viewed from a direction perpendicular to the substrate portion, the center of gravity of the resonating portion is located outside the joint area between the substrate portion and the connecting portion.

[0006] The vibration reduction device of the invention described in Patent Document 4 has an acoustic meta-structure that is attached to the vehicle body and blocks vibrations transmitted through the vehicle body, and includes a cross-shaped frame that is attached to the vehicle body and divides a certain space into certain areas, and vibrators that are configured at the corners of each area divided by the frame and have their own natural frequencies, blocking vibrations transmitted from the vehicle body through the frame.

[0007] The composite panel assembly of the invention described in US Pat. No. 5,999,333 includes a sound absorbing meta-structure sandwiched between a first elastic membrane and a second elastic membrane. The meta-structure includes a first honeycomb layer, a second honeycomb layer and an intermediate space therebetween. The first honeycomb layer has a partition wall defining a cavity resonator covered along a first side by the first elastic membrane. The second honeycomb layer has a partition wall defining a cavity resonator covered along a second side by the second elastic membrane.

[0008] The sound insulating wall assembly of the invention described in Patent Document 6 includes a plurality of walls defining a space, and at least one acoustic scatterer, a semi-scatterer, disposed within the space. The semi-scatterer has an opening and at least one channel. The at least one channel has a channel open end and a channel terminal, and the channel open end is in fluid communication with the opening.

[0009] Non-Patent Document 1 describes how the transfer matrix of a homogeneous, isotropic, rigid or flexible porous layer can be used to easily determine the characteristic impedance and wave number of the material, from which other acoustic quantities of interest can be calculated. The method described in Non-Patent Document 1 can be used to calculate the effective mass density and effective bulk modulus from the transfer matrix obtained from the sound pressure near the surface of an object. [Prior art documents] [Patent documents]

[0010] [Patent Document 1] JP 2005-250474 A [Patent Document 2] International Publication No. 2019 / 022245 [Patent Document 3] JP 2021-152584 A [Patent Document 4] JP 2020-91481 A [Patent Document 5] JP 2019-91013 A [Patent Document 6] Patent Publication No. 2022-78005 [Non-patent literature]

[0011] [Non-Patent Document 1] "A transfer-matrix approach forestimating the characteristic impedance and wave numbers of limp and rigid porous materials" The Journal of the Acoustical Society of America, Vol.107, Issue 3, pp. 1131-1152, March 2000, Bryan H. Song, J. Stuart Bolton Summary of the Invention [Problem to be solved by the invention]

[0012] The sound-damping panel described in Patent Document 1 has a rigid frame that is not flexible, and vibrations are transmitted to the seat via this rigid frame, so there is a risk that sufficient sound insulation cannot be obtained. In addition, if the surface on which the rigid frame is placed is curved or uneven, the sound-damping panel may not be stably held. In particular, since the panels of general vehicles (e.g., automobiles) have many curved or uneven parts, it is difficult to simply use the sound-damping panel of Patent Document 1 as a sound-insulating material for vehicles. In addition, the rigid frame has a large mass, and the increase in mass due to the sound-insulating material in the vehicle may be a problem.

[0013] The soundproofing material described in Patent Document 2 has a high support part, i.e., a high height extending from the seat in a direction perpendicular to the seat, and is preferably 25 mm or more. In order to stably support the seat with such a high support part, it is preferable that the support part has rigidity. As a result, there is a risk that sufficient sound insulation cannot be obtained because vibrations are transmitted through the support part, and it is difficult to place the soundproofing material on a curved or uneven placement surface such as a panel of a vehicle (e.g., an automobile). In addition, such a high support part leads to an increase in size and weight of the entire soundproofing material, and when placed on a panel of a vehicle, the soundproofing material occupies a large space inside the vehicle, reducing space efficiency, and there is a concern that it will hinder the installation of other components and get in the way of occupants.

[0014] In the sound insulation material described in Patent Document 3, the resonating part, which is the functional part that exerts the sound insulation effect, is exposed and not covered by a surrounding wall, etc., and there is a risk that the sound insulation performance will decrease or change if this resonating part comes into contact with other members or the human body. Therefore, it is necessary to provide a large space around the resonating part, which reduces the space efficiency.

[0015] The vibration reduction device described in Patent Document 4 does not have a base, but is composed of multiple vibrators and a frame connecting them. Therefore, like the sound insulation material in Patent Document 3, the vibrator, which is the functional part that exerts the sound insulation effect, is exposed, and if this vibrator comes into contact with other members or the human body, the sound insulation may be reduced or changed. In addition, in order to ensure the minimum structural strength of the vibration reduction device, the frame is required to have rigidity. As a result, since vibration is transmitted through the frame, there is a risk that sufficient sound insulation cannot be obtained, and it is difficult to place the device on a curved or uneven mounting surface such as a panel of a vehicle (e.g., an automobile).

[0016] The composite panel assembly of the invention described in Patent Document 5 has a first range having a negative bulk modulus and a second range having a negative mass density, and the first and second frequency ranges may overlap to define a double negative frequency range in which both the bulk modulus and mass density are negative. This is a configuration to provide desired sound absorption properties, but does not provide good sound insulation.

[0017] Patent Document 6 describes that the effective mass density of a sound-insulating wall assembly becomes negative at the resonant frequency, but does not describe or suggest the effect that this has on sound insulation.

[0018] Non-Patent Document 1 describes an effective method that can be used to calculate effective mass density and effective bulk modulus, but is not related to sound insulation structures.

[0019] Therefore, an object of the present invention is to provide a thin and lightweight sound insulation structure that can provide sufficient sound insulation and can be easily and stably placed on curved or uneven surfaces such as the panels of buildings, machinery, and vehicles (e.g., automobiles), and that has good sound insulation properties, particularly in the low frequency range of 2000 Hz or less. [Means for solving the problem]

[0020] The sound-proofing structure of the present invention includes a hollow frame structure having an opening in a portion thereof, and a weight portion located inside the hollow portion of the frame structure, the frame structure having a base portion facing the opening portion and a peripheral wall portion extending from the base portion toward the opening portion, one weight portion is disposed in one of the frame structures, the weight portion is attached to the base of the frame structure and extends in a direction toward the opening portion, the weight portion is surrounded by the base and the peripheral wall portion except for a portion facing the opening portion, and the weight portion extends from the base of the frame structure to the opening portion. a height of the peripheral wall portion in the direction toward the base that is greater than a height of the weight portion, and the weight portion constitutes a spring mass resonator having a spring portion having elasticity located on the side attached to the base, and a mass portion located on the opposite side of the weight portion to the side attached to the base and having a greater mass than the spring portion, and is characterized in that in a frequency band of 100 Hz or more and 2 kHz or less, there is at least one region where the effective mass density is negative and the effective bulk modulus is positive, and the difference between the maximum frequency and the minimum frequency in the region is 200 Hz or more. The term "elasticity" used here refers to the property of a solid substance that has been deformed by an external force returning to its original shape when the external force is removed, and includes energy elasticity and rubber elasticity (entropy elasticity). Here, a substance is said to have "elasticity" when it has at least one of energy elasticity and rubber elasticity (entropy elasticity). The frame structure may be cylindrical or angular, having the elastic sheet-like base and the peripheral wall standing on the base, one end of the hollow portion being closed by the base and the other end being open, and the weight portion standing on the same surface of the base as the peripheral wall standing on. The peripheral wall may be cylindrical with a circular, elliptical or oblong cross-sectional shape that defines each of the compartments, or may be angular with a polygonal cross-sectional shape, specifically a square, regular pentagon or regular hexagon, that defines each of the compartments. In a frequency band of 100 Hz or more and 2 kHz or less, the difference between the maximum frequency and the minimum frequency in the region where the effective mass density is negative and the effective bulk modulus is positive may be 500 Hz or less. The effective mass density in this region is -5000kg / m 3 More than 0kg / m 3 It may be the following: The effective bulk modulus in the region may be 0 Pa or more and 500,000 Pa or less.

[0021] The base portion, the peripheral wall portion and the spring portion may all be made of a material having rubber elasticity but not energy elasticity, a material having energy elasticity but not rubber elasticity, or a material having both rubber elasticity and energy elasticity. The base, the peripheral wall, and the spring may each have a dynamic storage modulus of 0.01 MPa or more and 100 MPa or less at 23° C. and at a frequency of 1 Hz to 1000 Hz. The base, the peripheral wall, and the spring may each be made of an elastic body having a loss tangent of 0.01 or more and 0.50 or less at 23° C. and at a frequency of 1 Hz to 1000 Hz. Specifically, the elasticity of the base, peripheral wall, and spring portion is evaluated by a dynamic storage modulus (E') obtained by measuring frequency dependency in tension or compression mode with a dynamic viscoelasticity measuring device in accordance with JIS K7244 and obtaining a master curve based on 23° C., and the dynamic storage modulus (E') is from 0.01 MPa to 100 MPa at 23° C. and frequencies of 1 Hz to 1000 Hz. More preferably, both the base and peripheral wall may be made of an elastic body having a dynamic storage modulus (E') of from 0.05 MPa to 50 MPa at 23° C. and frequencies of 1 Hz to 1000 Hz, and a loss tangent of from 0.05 to 0.45 at 23° C. and frequencies of 1 Hz to 1000 Hz. The mass portion of the weight portion may have a larger volume than the spring portion. The mass portion of the weight portion may be made of a material having a higher density than the spring portion. The thickness of the peripheral wall portion may be 0.5 mm or more and 5.0 mm or less, and is more preferably 1.0 mm or more and 3.0 mm or less. The thickness of the base may be 0.1 mm or more and 3.0 mm or less. The height in a direction perpendicular to the base may be 5 mm or more and 20 mm or less. The height of the peripheral wall in the direction perpendicular to the base may be 5 mm to 20 mm, and more preferably 10 mm to 20 mm. The peripheral wall may have a different height in some parts. The weight portion may have a height of 1 mm or more extending in a direction perpendicular to the base portion. The base portion may have a durometer A hardness of 30 or more, and the peripheral wall portion may have a durometer A hardness of 1 or more and 90 or less. The durometer A hardness can be obtained by measurement in accordance with JIS K 6253-3.

[0022] A plurality of the frame structures may be arranged side by side in a plane, and one of the weight portions may be arranged on each of the frame structures. The same weight portion may be disposed in all of the frame structures. Alternatively, some of the frame structures may have weight portions disposed therein that have a different configuration from the weight portions disposed in the other frame structures. The peripheral wall portion may include a plurality of first wall portions extending in a direction perpendicular to the base and extending in a first direction parallel to the base, and a plurality of second wall portions extending in a direction perpendicular to the base and extending in a second direction perpendicular to the first direction. The planar area of ​​the hollow portion of each of the frame structures is 100 mm 2 More than 1000mm 2 It may be the following: Area 1000cm 2 There may be from 10 to 1000 of the frame structures provided per unit area, and more preferably from 50 to 500 of the frame structures provided per unit area. Effect of the Invention

[0023] According to the present invention, it is possible to provide a thin and lightweight soundproofing structure that has sufficient soundproofing properties and can be easily and stably placed on curved or uneven surfaces such as the panels of buildings, machinery, and vehicles (e.g., automobiles), and that has particularly good soundproofing properties in the low frequency range of 2000 Hz or less. [Brief description of the drawings]

[0024] [Figure 1] FIG. 1A is a perspective view of a sound-proofing structure according to a first embodiment of the present invention, and FIG. 1B is a cross-sectional view taken along line AA thereof. [Diagram 2] FIG. 2(A) is an exploded perspective view of the sound-proofing structure shown in FIG. 1, and FIG. 2(B) is an exploded front view thereof. [Diagram 3] FIG. 1A is a perspective view of a sound-proofing structure according to a modified example of the first embodiment of the present invention, and FIG. 1B is a cross-sectional view taken along line AA thereof. [Figure 4] FIG. 1A is a cross-sectional view of a sound-insulating structure according to another modified example of the first embodiment of the present invention, and FIG. 1B is a perspective view of a weight portion of the sound-insulating structure. [Diagram 5] FIG. 1A is a cross-sectional view of a sound-insulating structure according to still another modified example of the first embodiment of the present invention, and FIG. 1B is a perspective view of a weight portion of the sound-insulating structure. [Figure 6] 6(A) and 6(B) are cross-sectional views of a sound-proof structure according to still another modified example of the first embodiment of the present invention. [Figure 7] 6(A) to 6(H) are cross-sectional views of a sound-proof structure according to still another modified example of the first embodiment of the present invention. [Figure 8] 5A is a perspective view of a sound insulation structure according to a second embodiment of the present invention, and FIG. 5B is a cross-sectional view taken along line AA thereof. [Figure 9] FIG. 13(A) is a cross-sectional view of a sound insulation structure according to a modification of the second embodiment of the present invention, and (B) is a cross-sectional view of a sound insulation structure according to another modification. [Figure 10] FIG. 1A is a plan view of an example of a sound insulation structure of the present invention having a single frame structure, and FIG. 1B is a plan view of a sound insulation structure of the present invention having a plurality of such frame structures. [Figure 11]FIG. 2A is a plan view of another example of a sound insulation structure of the present invention having a single frame structure, and FIG. 2B is a plan view of a sound insulation structure having a plurality of such frame structures. [Figure 12] FIG. 2A is a plan view of yet another example of a sound insulation structure of the present invention having a single frame structure, and FIG. 2B is a plan view of a sound insulation structure having a plurality of such frame structures. [Figure 13] FIG. 2A is a plan view of yet another example of a sound insulation structure of the present invention having a single frame structure, and FIG. 2B is a plan view of a sound insulation structure having a plurality of such frame structures. [Figure 14] FIG. 2A is a plan view of yet another example of a sound insulation structure of the present invention having a single frame structure, and FIG. 2B is a plan view of a sound insulation structure having a plurality of such frame structures. [Figure 15] FIG. 11 is a cross-sectional view showing a sound insulation structure according to a fourth embodiment of the present invention. [Figure 16] FIG. 2 is a cross-sectional view showing the sound-insulating structure of Comparative Example 1. [Figure 17] FIG. 4 is a cross-sectional view showing a sound-insulating structure of Comparative Example 2. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0025] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. [First embodiment] FIG. 1(A) is a perspective view of a sound insulation structure 1 according to a first embodiment of the present invention, and FIG. 1(B) is a cross-sectional view taken along line AA in FIG. 1(A) and turned upside down. FIG. 2(A) is an exploded perspective view of the sound insulation structure 1, and FIG. 2(B) is an exploded front view thereof. The sound insulation structure 1 includes a hollow frame structure 6 with a portion open, and a weight portion 4 located inside a hollow portion 5 of the frame structure 6. The frame structure 6 has a base portion 2 at a position facing the opening portion 5a, and a peripheral wall portion 3 extending from the base portion 2 toward the opening portion 5a. One weight portion 4 is disposed in one frame structure 6. The weight portion 4 is attached to the base portion 2 of the frame structure 6 and extends in a direction toward the opening portion 5a, and the weight portion 4 is surrounded by the base portion 2 and the peripheral wall portion 3 except for the position facing the opening portion 5a. In the example shown in Figs. 1 and 2, the frame structure 6 is cylindrical or rectangular, having an elastic sheet-like base (membrane) 2 and a peripheral wall (support wall) 3 erected on the base 2. The base 2 is disposed at a position that blocks one end of the hollow portion 5, and the other end of the hollow portion 5 is open without being blocked. The weight 4 is erected on the same surface of the base 2 as the surface on which the peripheral wall 3 is erected. The height H1 of the peripheral wall 3 in the direction from the base 2 of the frame structure 6 toward the opening 5a is greater than the height H2 of the weight 4. The weight 4 constitutes a spring-mass resonator having an elastic spring 4a located on the side attached to the base 2, and a mass (mass) 4b located on the opposite side of the side attached to the base 2 of the weight 4 and having a greater mass than the spring 4a. Elasticity here refers to the property of a solid material that has been deformed by an external force returning to its original shape when the external force is removed, and includes energy elasticity and rubber elasticity (entropy elasticity). Here, the term "having elasticity" refers to the presence of at least one of energy elasticity and rubber elasticity (entropy elasticity). In the sound insulation structure 1, there is at least one region in the frequency band of 100 Hz to 2 kHz inclusive where the effective mass density is negative and the effective bulk modulus is positive, and the difference between the maximum and minimum frequencies in that region is 200 Hz or more.

[0026] The peripheral wall 3 of this embodiment includes a first wall 3a extending in a first direction D1 parallel to the base 2, and a second wall 3b extending in a second direction D2 perpendicular to the first direction D1. A section (hollow portion) 5 having a square planar shape is formed, which is partitioned by the first wall 3a and the second wall 3b. In other words, the peripheral wall 3 is a rectangular tube having a square cross-sectional shape that defines the hollow portion 5. The base 2 and the peripheral wall 3 are preferably made of a flexible material such as rubber, elastomer, or resin foam. The flexible material referred to here is any one of a material that does not have energy elasticity but has rubber elasticity, a material that does not have rubber elasticity but has energy elasticity, and a material that has both rubber elasticity and energy elasticity.

[0027] In this embodiment, the part of the weight part 4 attached to the base part 2 is the spring part 4a, and the part opposite to the side attached to the base part 2 is the mass part 4b, which has a larger mass than the spring part 4a. In the example shown in Figs. 1-2, the spring part 4a and the mass part 4b have the same shape and the same dimensions, but are made of different materials. The spring part 4a is made of a flexible material, and the mass part 4b is made of a material having a higher density than the material constituting the spring part 4a. A spring mass resonator is configured in which the spring part 4a functions as a spring and the mass part 4b functions as a mass. In addition to the spring part 4a of the weight part 4, the base part 2 may also function as a part of the spring of the spring mass resonator. Furthermore, the air in the hollow part 5 surrounded by the base part 2 and the peripheral wall part 3 may also function as a part of the spring of the spring mass resonator (air spring). It is preferable that the spring portion 4a is also made of a flexible material, i.e., a material that has rubber elasticity but not energy elasticity, a material that has energy elasticity but not rubber elasticity, or a material that has both rubber elasticity and energy elasticity.

[0028] According to the sound-proofing structure 1 of this embodiment, the vibration of the base 2 is controlled by the action of a spring-mass resonator constituted by the spring portion 4a and the mass portion 4b of the weight portion 4. In particular, in a specific frequency range (for example, frequencies below 1000 Hz, which is the main frequency band of road noise in automobiles), the membrane vibration is significantly reduced, and as a result, the radiation sound from the base 2 is reduced, and high sound insulation is achieved.

[0029] The effective mass density and effective bulk modulus are parameters that represent the material constants of an equivalent homogeneous material by replacing the structure of the target object with the equivalent homogeneous material. For example, they can be calculated by a transfer matrix obtained from the sound pressure near the surface of the homogeneous material with reference to the method described in Non-Patent Document 1. The viscoelastic data of the material used to calculate the effective mass density and effective bulk modulus may be a constant, or for materials with high frequency dependence, frequency-dependent data of viscoelasticity may be used. If either the effective mass density or the effective bulk modulus shows a negative value, the real part of the sound speed becomes 0, which means that sound waves do not propagate within the medium, and therefore high sound insulation can be expected. In addition, the effective mass density and effective bulk modulus can be controlled by the shape, viscoelasticity of the material, temperature, humidity, etc.

[0030] In the sound insulation structure 1 of this embodiment, there is at least one region in the frequency band of 100 Hz to 2 kHz inclusive where the effective mass density is negative and the effective bulk modulus is positive, and the difference between the highest and lowest frequencies in this region is 200 Hz or more, so that a particularly large sound insulation effect can be achieved. It is considered that a sound insulation structure 1 in which the difference between the highest and lowest frequencies in this region is 500 Hz or less can be manufactured relatively easily. And, when the effective mass density in this region is -5000 kg / m 3 More than 0kg / m 3 and the effective bulk modulus is in the range of 0 Pa to 500,000 Pa, a greater sound insulation effect can be obtained, which is preferable. 3 More than 0kg / m 3or less, more preferably the effective bulk modulus is in the range of 0 Pa to 300,000 Pa, and further preferably the effective mass density is -2000 kg / m 3 More than 0kg / m 3 or less, and more preferably the effective bulk modulus is in the range of 0 Pa or more and 250,000 Pa or less. Note that such a region in which the effective mass density is negative and the effective bulk modulus is positive may exist not only in one place but also in multiple places in the frequency band of 100 Hz to 2 kHz or less. In that case, in each of the multiple such regions, as described above, the difference between the maximum frequency and the minimum frequency is 200 Hz to 500 Hz or less, and the effective mass density is -5000 kg / m 3 More than 0kg / m 3 The effective bulk modulus is preferably in the range of 0 Pa to 500,000 Pa, and the effective mass density is preferably in the range of -3,000 kg / m 3 More than 0kg / m 3 or less, more preferably the effective bulk modulus is in the range of 0 Pa to 300,000 Pa, and further preferably the effective mass density is -2000 kg / m 3 More than 0kg / m 3 More preferably, the effective bulk modulus is in the range of 0 Pa or more and 250,000 Pa or less. The effective mass density and effective bulk modulus described in this specification are measured at room temperature under atmospheric conditions.

[0031] The base 2, the peripheral wall 3, and the spring 4a of the sound insulation structure 1 of this embodiment are all made of an elastic body having a dynamic storage modulus (E') of 0.01 MPa to 100 MPa at 23° C. and a loss tangent (tan δ) of 0.01 to 0.50 at 23° C. and a frequency of 1 Hz to 1000 Hz, preferably a dynamic storage modulus (E') of 0.05 MPa to 50 MPa at 23° C. and a loss tangent (tan δ) of 0.05 to 0.50 at 23° C. and a frequency of 1 Hz to 1000 Hz. The dynamic storage modulus (E') and the loss tangent (tan δ) are determined by creating a master curve based on 23° C. using a dynamic viscoelasticity tester. When the dynamic storage modulus (E') is 0.01 MPa or more at 23°C and frequencies of 1 Hz to 1000 Hz, the sound insulation properties in the target frequency band are good, and the shape retention of the base 2 and the peripheral wall 3 is also good. When the dynamic storage modulus (E') is less than 100 MPa at 23°C and frequencies of 1 Hz to 1000 Hz, the vibration in the target frequency band for sound insulation is good, and the sound insulation structure 1 becomes rigid and easy to install. The base 2 and the peripheral wall 3 may be made of the same material or different materials. It is preferable that the base 2 is also made of a flexible material, that is, a material that does not have energy elasticity but has rubber elasticity, a material that does not have rubber elasticity but has energy elasticity, or a material that has both rubber elasticity and energy elasticity.

[0032] The base 2 is preferably a hard elastic film since the weight 4 is attached to it. The dynamic storage modulus (E') of the base 2 is preferably 15 MPa or more, and the thickness (film thickness) is preferably 1 μm or more and 3000 μm or less, and more preferably 10 μm or more and 1000 μm or less. Since the base 2 has a certain thickness or more, sufficient thickness can be secured, making it easy to handle. On the other hand, since the thickness of the base 2 is not too thick, an increase in the thickness and weight of the entire sound insulation structure 1 is prevented, and the entire sound insulation structure 1 does not become too hard, making it easy to install. The material of the base 2 preferably has a durometer A hardness of 30 or more, more preferably 70 or more, according to JIS K6253. By setting the durometer A hardness of the base 2 within the above range, deterioration of the vibration of the base 2 is prevented, and sound insulation in the frequency band to be sound-insulated is improved. The stiffness (axial stiffness) k of the base 2 is expressed as k = E' × A / L from the dynamic storage modulus E', the cross-sectional area A of the base 2, and the thickness L of the base 2. When the area of ​​the base 2 to be evaluated for stiffness is 1000 cm 2 When the stiffness k is 10 4 N / mm or more 10 9 It is preferable that the resistance is less than 10 N / mm. 5 N / mm or more 10 8 It is more preferable that the area of ​​the base 2 is 1000 cm 2 When the stiffness is 10 4 By having a vibration damping ratio of 1000 N / mm or more, it is possible to suppress deterioration of the vibration of the base 2, and the sound insulation performance of the target frequency band for sound insulation is improved. 2 When the stiffness is 10 9 When the elastic modulus is less than N / mm, the sound insulation structure 1 becomes flexible and easy to install. The bending stiffness K of the base 2 is expressed as K=E'×I from the dynamic storage elastic modulus E' and the second moment of area I, and the second moment of area I is expressed as I=b×h from the thickness h of the base 2 and the width b of the base 2. 3 / 12. The area of ​​the base 2 to be evaluated is 1000 cm 2 When the bending stiffness K is 1N / mm 2 Over 10 5 N / mm 2 It is preferable that the resistance is less than 10 N / mm2 5×10 or more 4 N / mm 2 More preferably, the area of ​​the base 2 is 1000 cm or less. 2 The bending stiffness K when 2 By satisfying the above, the vibration of the base 2 is improved, and the deterioration of the sound insulation performance in the frequency band to be sound-insulated can be suppressed. 2 When the bending stiffness K is 10 5 N / mm 2 When the above-mentioned condition is satisfied, the sound insulation structure 1 becomes flexible and the installation property becomes favorable. The cross-sectional shape of the base 2 is not particularly limited, and may be flat or may have irregularities.

[0033] Materials for the base 2 include crosslinked (vulcanized) rubber, thermoplastic elastomer, and plastic. Examples of crosslinked (vulcanized) rubber include natural rubber (NR), isoprene rubber (IR), butadiene rubber (BR), styrene-butadiene rubber (SBR), chloroprene rubber (CR), butyl rubber (IIR), nitrile rubber (NBR), hydrogenated nitrile rubber (HNBR), ethylene-α-olefin-non-conjugated polyene copolymers such as ethylene-propylene rubber (EPM), ethylene-propylene-diene rubber (EPDM) and ethylene-butene-diene rubber (EBDM), chlorosulfonated polyethylene (CSM), chlorinated polyethylene (CM), acrylic rubber (ACM), ethylene-acrylic rubber (AEM), ethylene-vinyl acetate rubber (EVA), epichlorohydrin rubber (CO, ECO), polysulfide rubber (T), silicone rubber (Q) such as methylvinylsilicone rubber (VMQ) and fluorinated silicone rubber (FVMQ), urethane rubber (U), and fluororubber (FKM). These crosslinked (vulcanized) rubbers can be used alone or in combination of two or more kinds. Examples of the crosslinking (vulcanization) method include a method of crosslinking (vulcanization) by heating using an organic peroxide, a phenolic resin, an oxime compound, sulfur, a sulfur-based compound, or a polyamine compound as a crosslinking agent (vulcanizing agent), or a method of crosslinking by irradiating with an electron beam. The crosslinked (vulcanized) rubber may contain various known compounding agents (reinforcing agents such as carbon black and silica, fillers such as calcium carbonate, softeners such as paraffin oil and plasticizers, processing aids, antioxidants, light stabilizers, flame retardants, antifungal agents, acid acceptors, silane coupling agents, antistatic agents, ultraviolet absorbing agents, etc.) that are generally used as rubber compounding agents. These crosslinked (vulcanized) rubbers, crosslinking agents (vulcanizing agents), and compounding agents may be made from biomass raw materials.

[0034] Examples of the thermoplastic elastomer include olefin-based thermoplastic elastomers, styrene-based thermoplastic elastomers, polyester-based thermoplastic elastomers, polyvinyl chloride-based thermoplastic elastomers, and ethylene-vinyl acetate-based thermoplastic elastomers. Examples of the plastic include polyethylene, polypropylene, polystyrene, polyethylene terephthalate, polyvinyl chloride, and composite resins containing these. These thermoplastic elastomers and plastics may be made from biomass raw materials.

[0035] Specifically, the material of the base 2 is preferably ethylene-propylene-diene rubber, a thermoplastic olefin-based elastomer, a thermoplastic styrene-based elastomer, polyethylene, polypropylene, polyethylene terephthalate, thermoplastic polyurethane, or the like.

[0036] The peripheral wall 3 is preferably made of a soft, flexible material within a range capable of supporting the base 2. The thickness of the peripheral wall 3 is preferably 0.5 mm or more and 5.0 mm or less, and more preferably 1.0 mm or more and 3.0 mm or less. When the thickness of the peripheral wall 3 is 0.5 mm or more, the shape retention of the sound insulation structure 1 is good. When the thickness of the peripheral wall 3 is 5.0 mm or less, the vibration of the base 2 is good, the sound insulation of the frequency band to be sound-insulated is good, and the increase in the weight of the entire sound insulation structure 1 can be suppressed. The height of the peripheral wall 3 extending in a direction perpendicular to the base 2 is preferably 5 mm or more and 20 mm or less, and more preferably 10 mm or more and 20 mm or less. The peripheral wall 3 may have a different height in parts. When the height of the peripheral wall 3 is different in parts, the higher part may be 10 mm or more and 20 mm or less, more preferably 12 mm or more and 20 mm or less, and even more preferably 14 mm or more and 20 mm or less. The peripheral wall 3 is not too low in height, so that the weight 4 can have a sufficient height as a spring mass resonator. The peripheral wall 3 is not too high in height, so that the overall weight can be reduced. The material of the peripheral wall 3 preferably has a durometer A hardness according to JIS K6253 of 1 or more and 90 or less, more preferably 10 or more and 70 or less. The peripheral wall 3 has a durometer A hardness of 1 or more, so that the shape retention of the sound insulation structure 1 can be maintained. The peripheral wall 3 has a durometer A hardness of 90 or less, so that vibration from the peripheral wall 3 is prevented from being transmitted to the base 2, which would cause a deterioration in the sound insulation performance, and the sound insulation structure 1 becomes flexible and easy to install. The stiffness k of the peripheral wall 3 is expressed as k=E'×A / L, where E' is the dynamic storage elastic modulus, A is the cross-sectional area of ​​the peripheral wall 3, and L is the height of the peripheral wall 3. When the area of ​​the peripheral wall 3 to be evaluated for stiffness is 1000 cm 2 When the stiffness k is 10N / mm or more, 6 It is preferable that the resistance is less than 10 N / mm. 2 N / mm or more 10 5 It is more preferable that the surface area of ​​the peripheral wall 3 is 1000 cm 2 When the area of ​​the peripheral wall 3 is 1000 cm, the stiffness k is 10 N / mm or more, so that the shape retention of the sound insulation structure 1 can be maintained.2 When the stiffness k is 10 6 By setting the vibration resistance to N / mm or less, the vibration from the peripheral wall 3 is prevented from being transmitted to the base 2, which would deteriorate the sound insulation performance, and the sound insulation structure 1 becomes rigid, which improves the ease of installation.

[0037] Examples of materials for the peripheral wall 3 include crosslinked (vulcanized) rubber, thermoplastic elastomers, and resin foams. The crosslinked (vulcanized) rubber and thermoplastic elastomers may be the same as those listed as materials for the base 2. The resin foams may have either a closed cell structure or an open cell structure, and examples of the resin foams include polyurethane foam, polystyrene foam, polyethylene foam, and ethylene-vinyl acetate rubber (EVA) foam. Specifically, the materials for the peripheral wall 3 are preferably ethylene-propylene-diene rubber, urethane rubber, silicone rubber, thermoplastic olefin-based elastomers, thermoplastic styrene-based elastomers, thermoplastic polyurethane, and polyurethane foam. These resin foams may be made of biomass raw materials.

[0038] The material of the spring portion 4a of the weight portion 4 is a flexible material such as crosslinked (vulcanized) rubber, thermoplastic elastomer, resin foam, etc. The crosslinked (vulcanized) rubber, thermoplastic elastomer, and resin foam may be the same as the materials given as the materials of the peripheral wall portion 3. Specifically, the material of the spring portion 4a of the weight portion 4 is preferably ethylene-propylene-diene rubber, urethane rubber, silicone rubber, thermoplastic olefin-based elastomer, thermoplastic styrene-based elastomer, thermoplastic polyurethane, polyurethane foam, etc.

[0039] The material of the mass portion 4b is not particularly limited, but it is made of resin, metal, or the like, and the mass portion 4b has a larger mass than the spring portion 4a, for example, a mass of 0.1 g or more and 2.0 g or less. The mass portion 4b preferably has a mass at least twice the mass of the spring portion 4a. When the weight of the mass portion 4b is at least twice the mass of the spring portion 4a, the weight portion 4 can be sufficiently resonated in the frequency range to be sound-insulated, and a good sound-insulating effect can be obtained. When the material of the mass portion 4b is resin, the resin may be made of a biomass material.

[0040] The spring constant (rigidity) of the spring portion 4a is determined based on the mass of the mass portion 4b so that the resonant frequency coincides with the frequency to be mainly sound-insulated. As an example, when the mass portion 4b has a mass of 1.0 g and the frequency to be mainly sound-insulated is 1000 Hz or less, the spring constant of the spring portion 4a is 0.5 N / mm or more and 100 N / mm or less, and more preferably 1 N / mm or more and 50 N / mm or less.

[0041] As described above, even if the peripheral wall 3 is thin and soft like the base 2, excellent sound insulation can be obtained by the action of the spring mass resonator. The softness of the peripheral wall 3 allows for good installation on various members (for example, automobile panels having unevenness or curved surfaces). In this embodiment, the base 2, the peripheral wall 3, and the weight 4 are all relatively light, and the dimensions in the direction perpendicular to the base 2 are relatively small. As described above, the sound insulation structure 1 of this embodiment is lightweight and thin, yet provides high sound insulation in a specific frequency range (for example, frequencies below 1000 Hz, which are the main frequency band of road noise in automobiles) as described above. The peripheral wall 3 made of a flexible material can be easily and stably installed on a flat mounting surface or a curved or uneven mounting surface without being fixed by adhesive or the like.

[0042] FIG. 3(A) is a perspective view of a sound insulation structure 1 according to a modification of the first embodiment of the present invention, and FIG. 3(B) is a cross-sectional view taken along line AA in FIG. 3(A) and inverted. FIG. 4(A) is a cross-sectional view of the sound insulation structure 1 according to another modification, and FIG. 4(B) is a perspective view of the weight portion 4 of the sound insulation structure 1. FIG. 5(A) is a cross-sectional view of the sound insulation structure 1 according to yet another modification, and FIG. 5(B) is a perspective view of the weight portion 4 of the sound insulation structure 1. FIGS. 6(A) to 6(B) are cross-sectional views showing yet another modification of the first embodiment of the present invention. In the modification shown in FIGS. 3 to 6, the spring portion 4a and the mass portion 4b of the weight portion 4 have different shapes and different dimensions. In the modification shown in FIGS. 3(A) and 3(B), the spring portion 4a is a small-diameter cylindrical portion, and the mass portion 4b is a large-diameter cylindrical portion. In the modified example shown in Figs. 4(A) and 4(B), the spring portion 4a is thin and cylindrical, the mass portion 4b is spherical, and the diameter of the cross-sectional shape of the cylindrical spring portion 4a is smaller than the diameter of the spherical mass portion 4b. In the modified example shown in Figs. 5(A) and 5(B), the spring portion 4a is truncated cone, the mass portion 4b is cylindrical, and the diameter of the smallest part of the truncated cone spring portion 4a is substantially equal to the diameter of the cylindrical mass portion 4b. In the modified example shown in Figs. 3(A) to 4(B), the mass portion 4b has a larger volume than the spring portion 4a. Therefore, even if the spring portion 4a and the mass portion 4b are made of the same material, the mass portion 4b has a larger mass than the spring portion 4a, and a spring-mass resonator can be formed. However, in this modified example, the spring portion 4a and the mass portion 4b may be made of different materials, and the mass portion 4b may have a larger mass than the spring portion 4a. On the other hand, in the modified example shown in Fig. 5(A) and 5(B), the spring portion 4a has a larger volume than the mass portion 4b. In this case, the mass portion 4b is made of a material having a higher density than the spring portion 4a, and the mass portion 4b has a larger mass than the spring portion 4a, so that a spring mass resonator can be formed. If the spring portion 4a has a truncated cone shape tapered toward the direction away from the base portion 2 as in the modified example shown in Fig. 5(A) and 5(B), the base portion 2 and the spring portion 4a are molded integrally with each other, and the spring portion 4a can be easily released from the mold. In the modified example shown in Fig. 6(A), the mass portion 4b of the weight portion 4 has a triangular cross-sectional shape tapered toward the opening portion 5a.In the modification shown in Fig. 6(B), the mass portion 4b of the weight portion 4 has a larger dimension (height) in the direction from the base portion 2 toward the opening portion 5a than the spring portion 4a. The shape and dimensions of the weight portion 4 of the present invention are not limited, and the shapes shown in Figs. 1 to 6 and various other shapes not shown can be adopted. The weight portion 4 is formed in any shape and dimensions selected so as to satisfy the performance of the spring mass resonator required for sound insulation and to be able to be accommodated in the hollow portion 5.

[0043] 7(A) to 7(H) are cross-sectional views of a sound insulation structure 1 according to another modification of the first embodiment of the present invention. The modifications shown in FIGS. 3 to 6 have different shapes and dimensions of the weight portion 4, but the modification shown in FIG. 7 has different shapes and dimensions of the frame structure 6. In the modification shown in FIG. 7(A), the height of the peripheral wall portion 3 is high. In the modification shown in FIG. 7(B), the peripheral wall portion 3 is formed obliquely so that the hollow portion 5 widens from the base portion 2 side toward the opening portion 5a side. In the modification shown in FIG. 7(C), the peripheral wall portion 3 is formed obliquely so that the hollow portion 5 narrows from the base portion 2 side toward the opening portion 5a side. In the modification shown in FIG. 7(D), the opposing peripheral walls 3 are positioned parallel to each other and inclined in the same direction, and the size of the hollow portion 5 does not change on either the base portion 2 side or the opening portion 5a side. In the modified example shown in Fig. 7(E), the peripheral wall 3 is bent, and the hollow portion 5 expands from the base 2 to the middle portion in the direction from the base 2 side toward the opening portion 5a side, and then narrows from the middle portion to the opening portion 5a. In the modified example shown in Fig. 7(F), the peripheral wall 3 has a shape in which bending similar to that of the peripheral wall 3 of the modified example shown in Fig. 7(E) is repeated twice in the direction from the base 2 side toward the opening portion 5a side, and the hollow portion 5 repeatedly expands and contracts. In the modified example shown in Fig. 7(G), the peripheral wall 3 is curved in an outwardly convex arc shape, and the hollow portion 5 expands from the base 2 to the middle portion in the direction from the base 2 side toward the opening portion 5a side, and then narrows from the middle portion to the opening portion 5a. In the modified example shown in FIG. 7(H), the peripheral wall 3 has a shape in which the hollow portion 5 is curved twice in the direction from the base 2 side toward the opening portion 5a side, similar to the peripheral wall 3 of the modified example shown in FIG. 7(G), and the hollow portion 5 is repeatedly expanded and contracted. In the modified examples shown in FIG. 7(G) and 7(H), the base 2 and the peripheral wall 3 are continuous, but the part to which the weight 4 is attached is the base 2, and the part from the base 2 to the opening portion 5a is the peripheral wall 3. The shape and dimensions of the frame structure 6 of the present invention are not limited, and the shapes shown in FIG. 1 and 7 and various other shapes not shown can be adopted. Furthermore, weights 4 of various shapes and dimensions and frame structures 6 of various shapes and dimensions may be arbitrarily combined.

[0044] [Second embodiment] FIG. 8(A) is a perspective view of a sound insulation structure 7 according to a second embodiment of the present invention, and FIG. 8(B) is a cross-sectional view taken along line AA in FIG. 8(A) and turned upside down. The sound insulation structure 7 according to this embodiment has a configuration in which a plurality of frame structures 6 are arranged side by side in a plane, and each frame structure 6 has one weight portion 4 arranged thereon. The base portions 2 of the frame structures 6 are integrated, and a plurality of peripheral wall portions 3 are erected on one surface of the large-area base portion 2. In the example shown in FIG. 8, the frame structures 6 are closely positioned. Specifically, a plurality of first wall portions 3a extending in a first direction D1 are arranged in parallel, and a plurality of second wall portions 3b extending in a second direction D2 are arranged in parallel, and the first wall portions 3a and the second wall portions 3b are integrated at the intersections. In this way, the multiple first walls 3a and the multiple second walls 3b form a lattice structure, and multiple hollow sections (compartments) 5, each of which has a square planar shape and is partitioned by the first walls 3a and the second walls 3b, are arranged in a matrix. In other words, the peripheral wall 3 has a structure in which multiple angular tubes, each of which has a square cross-sectional shape that defines each hollow section (compartment) 5, are arranged in a matrix.

[0045] The frame structure 6 of the sound insulation structure 7 of this embodiment has a base 2 with an area of ​​1000 cm 2 It is preferable that 10 to 1000 frames are provided per frame, and more preferably 50 to 500 frames are provided per frame. By providing 10 or more frame structures 6, it is possible to provide a large effect of providing a plurality of frame structures 6 and having each frame structure 6 exert a sound insulation effect. In addition, by having 1000 or less frame structures 6, it is possible to suppress an increase in the weight of the entire sound insulation structure 7. The planar area of ​​each hollow portion 5 of each frame structure 6 is 100 mm 2 More than 1000mm 2 It is preferable that the length is less than 200 mm. 2 More than 800mm 2It is more preferable that the height is 5 mm or less. If the area of ​​the planar shape of the hollow portion 5 of each frame structure 6 is not too small, the weight portion 4 can be easily arranged inside, and if the area is not too large, the weight portion 4 can have a sufficient effect on the base portion 2, and a large sound insulation property can be obtained. The height of the entire sound insulation structure 7 in the direction perpendicular to the base portion 2 is preferably 5 mm or more and 20 mm or less. If the height of the entire sound insulation structure 7 is not too low, the weight portion 4 can have a sufficient height as a spring mass resonator, and if the height of the entire sound insulation structure 7 is not too high, the increase in the weight of the entire sound insulation structure 1 can be suppressed. Note that each drawing shows each hollow portion 5 and the peripheral wall portion 3, etc., in a schematic manner, and the number of frame structures 6, the area of ​​the hollow portion 5, and the height of the peripheral wall portion 3 may not be shown strictly and accurately, or may not be unified in each drawing, but it is preferable that the number of frame structures 6, the area of ​​the hollow portion 5, and the height of the peripheral wall portion 3 are appropriately designed to be within the above-mentioned numerical ranges. In this embodiment, the same weight portions 4 may be arranged in all frame structures 6, but some frame structures 6 may be arranged with weight portions 4 having a different configuration from the weight portions 4 arranged in other frame structures 6.

[0046] Figure 9 is a cross-sectional view of a sound insulation structure 7 of a modified example of the second embodiment of the present invention. In the modified example shown in Figure 9(A), a plurality of frame structures 6 are arranged at intervals 8. The base 2 of each frame structure 6 is integrated, and adjacent frame structures 6 are connected to each other by an extension of the base 2. In the modified example shown in Figure 9(B), a plurality of frame structures 6 are also arranged at intervals 8, and adjacent frame structures 6 are connected to each other by a connecting piece 9. The connecting piece 9 may be made of the same material as the base 2.

[0047] In any of the first and second embodiments, the base 2 and the peripheral wall 3 can be formed by integral molding or two-color molding using the above-mentioned materials by injection molding, compression molding, press molding, extrusion molding, transfer molding, casting, etc. Furthermore, a part of the weight 4 can also be formed by integral molding, two-color molding, insert molding, etc., together with the base 2 and the peripheral wall 3 using the above-mentioned materials. However, the base 2, the peripheral wall 3, and the weight 4 may be formed separately, and then joined together by adhesion or heat fusion to assemble the sound-proofing structure 1, 7.

[0048] In the configuration of the sound insulation structures 1 and 7 described above, as shown in Figs. 10(A) and 10(B), the peripheral wall 3 includes a plurality of first wall portions 3a extending in a first direction D1 parallel to the base 2 and a plurality of second wall portions 3b extending in a second direction D2 perpendicular to the first direction D1, and the planar shape of the hollow portion 5 is a square. The peripheral wall portion 3 is a square tube having a square cross-sectional shape that defines the hollow portion 5. In the example shown in Fig. 10(A), the sound insulation structure 1 is composed of a single frame structure 6 and a weight portion 4. In the example shown in Fig. 10(B), the sound insulation structure 7 is composed of a plurality of frame structures 6 and weight portions 4, that is, a large number of square tube-shaped peripheral wall portions 3 are arranged side by side, and the peripheral wall portions 3 of adjacent frame structures 6 are integrated. However, the configuration is not limited to this. For example, as shown in Figs. 11(A) and 11(B), the planar shape of the frame structure 6 may be triangular, and the peripheral wall portion 3 may be a square tube having a triangular cross-sectional shape that defines the hollow portion 5. As shown in Figs. 12(A) and 12(B), the planar shape of the frame structure 6 may be pentagonal, and the peripheral wall portion 3 may be a square tube having a pentagonal cross-sectional shape that defines the hollow portion 5. As shown in Figs. 13(A) and 13(B), the planar shape of the frame structure 6 may be hexagonal, and the peripheral wall portion 3 may be a square tube having a hexagonal cross-sectional shape that defines the hollow portion 5, forming a so-called honeycomb structure. Furthermore, as shown in Figs. 14(A) and 14(B), the planar shape of the frame structure 6 may be circular, and the peripheral wall portion 3 may be cylindrical having a circular cross-sectional shape that defines the hollow portion 5. In the configurations shown in Figs. 12(B) and 14(B), a gap 8 is generated between the frame structures 6, and adjacent frame structures 6 may be connected to each other at this gap 8 by an extension part of the base 2 or a connecting piece 9, as in the configuration shown in Fig. 9. In the configurations shown in Figs. 10(B), 11(B), and 13(B), no gap 8 is generated between the frame structures 6. Furthermore, the planar shape of the frame structure 6 may be various shapes not shown, such as a rectangle, a parallelogram, a trapezoid, a polygon having heptagons or more, an ellipse, an oval, or the like, or may be an irregular shape. The peripheral wall 3 is formed to have a shape and dimensions that match the planar shape of the frame structure 6.

[0049] The sound insulation structure 1,7 of the present invention is very thin and lightweight, and can be easily placed on a curved or uneven surface, so it may be placed on the panel of a vehicle, particularly an automobile, for use. The panel of an automobile or the like is basically a plate with no air permeability, and examples thereof include a metal plate (iron plate, steel plate, aluminum plate) and a resin plate. When the panel on which the sound insulation structure 1,7 is placed is a metal plate, its thickness is preferably in the range of 0.5 mm to 2.0 mm, and when it is a resin plate, its thickness is preferably in the range of 0.5 mm to 20 mm. When the sound insulation structure 1,7 is placed on the panel of an automobile, it is preferable that the end face of the peripheral wall portion 3 of the sound insulation structure 1,7 opposite to the side attached to the base portion 2 is placed on the panel. In this case, the peripheral wall portion 3 and the panel may or may not be bonded to each other, but it is preferable that the peripheral wall portion 3 is placed on the panel without being bonded to the panel.

[0050] The sound insulation structure 1, 7 of the present invention may be used alone or in combination with other members (not shown). When the sound insulation structure 1, 7 of the present invention is used in combination with other members, it may be laminated or joined to the other members. When laminated or joined to other members, the sound insulation structure 1, 7 may be placed so as to be in contact with the portion (e.g., an automobile panel) on which the sound insulation structure 1, 7 is placed, or the other members may be placed so as to be in contact with the portion. The other members used in combination with the sound insulation structure 1, 7 may be made of various materials.

[0051] Examples of locations in which the sound insulation structures 1, 7 of the present invention are installed in an automobile include, in the engine compartment, engine head covers, engine body covers, hood insulators, front-dash insulators, air box walls, air intake cleaners, dust side ducts, and under covers; in the cabin, examples include dash insulators, dash panels, floor carpets (floor silencers), spacers, door trims, the inside of door trims, instrument panels, instrument center boxes, instrument upper boxes, air conditioner housings, roof trims, the inside of roof trims, sun visors, air conditioning ducts for rear seats, cooling ducts of battery cooling systems in battery-equipped vehicles, cooling fans, center console trims, the inside of the console, parcel trims, parcel panels, seat headrests, front seat backs, and rear seat backs; and in the trunk, examples include trunk side trims, the inside of trims, and drafter covers. In addition, the sound-insulating structures 1, 7 of the present invention can be installed within the frame of an automobile or between panels, and can also be installed in under-covers under the floor located outside the vehicle, fender protectors, tailgates, wheel covers, aerodynamic covers for suspensions, and the like.

[0052] Specific examples and comparative examples of the sound insulation structure of the present invention will be described below. [Example 1] A sound insulation structure 1 according to a first embodiment of the present invention has substantially the same structure as that of the first embodiment shown in Figures 1 and 2. The base portion 2 and the peripheral wall portion 3 of this embodiment have a Young's modulus of dynamic storage elastic modulus (E') of 13.2 MPa at 23°C and a frequency of 1 Hz, and a density of 1390 kg / m 3The weight portion 4 in this embodiment is made of EPDM (ethylene-propylene-diene rubber) having a Poisson's ratio of 0.49 and a loss tangent (tan δ) of 0.12 at 23°C and a frequency of 1 Hz as a damping (loss factor). The film thickness of the base portion 2 is 0.5 mm. The peripheral wall portion 3 has a plate thickness of 0.8 mm and a height of 9.5 mm in a direction perpendicular to the base portion 2. Of the weight portion 4 in this embodiment, the spring portion 4a which is the portion attached to the base portion 2 has a dynamic storage modulus (E') of 0.6 MPa at 23°C and a frequency of 1 Hz as a Young's modulus, and a density of 1167 kg / m 3 The spring portion 4a is a cylinder with a radius of 3 mm and a height of 3 mm, and is made of silicone rubber with a Poisson's ratio of 0.49 and a loss tangent of 0.17 as Damping (Loss Factor). The mass of the spring portion 4a is 0.09 g. The mass portion 4b, which is the portion of the weight portion 4 opposite to the side attached to the base portion 2, has a dynamic storage modulus (E') of 210,000 MPa at 23°C and a frequency of 1 Hz as Young's modulus, and a density of 7,800 kg / m 3 The mass portion 4b is a cylinder having a radius of 3 mm and a height of 3 mm, and is made of stainless steel having a Poisson's ratio of 0.31 and a loss tangent of 0.001 as a Damping (Loss Factor). The mass portion 4b has a mass of 0.7 g.

[0053] The sound insulation structure 1 of this embodiment has an overall thickness of 10 mm and an areal density of 3.63 kg / m 2The region (frequency range) in which the effective mass density is negative and the effective bulk modulus is positive in the frequency band of 100 Hz to 2 kHz in the air at room temperature of this sound insulation structure 1 is in the range of 280 Hz to 530 Hz. Therefore, the difference between the highest frequency and the lowest frequency in this region is 250 Hz. The sound insulation of this sound insulation structure 1 was obtained. Specifically, using the acoustic analysis software Actran ver 2022.1, an acoustic structure coupling analysis was performed by the finite element method. The acoustic structure coupling analysis was performed under conditions simulating a periodic structure, the sound pressure levels at four specific points were obtained, and the effective material constant was obtained from the transfer matrix obtained therefrom. Furthermore, the transmission loss at each frequency for a perpendicularly incident sound wave was obtained. When the maximum value of the transmission loss in the region (280Hz to 530Hz) where the effective mass density is negative and the effective bulk modulus is positive in the frequency band of 100Hz to 2kHz under room temperature atmosphere was compared with the theoretical value of the sound insulation calculated based on the mass law of the sound insulation structure 1 of this embodiment, the increase was 14.3 [dB]. The maximum value of the transmission loss in the aforementioned region (280Hz to 530Hz) was exhibited at 300Hz.

[0054] [Example 2] The sound insulation structure 1 of Example 2 of the present invention has substantially the same structure as the modified example of the first embodiment shown in FIG. 3. The base portion 2 and the peripheral wall portion 3 of this example have the same configuration as the base portion 2 and the peripheral wall portion 3 of Example 1. However, the configuration of the weight portion 4 is different from that of Example 1. The spring portion 4a and the mass portion 4b of the weight portion 4 of this example are both made of silicone rubber, the same as the spring portion 4a of Example 1. The spring portion 4a is a cylinder with a radius of 3 mm and a height of 3 mm, and has a mass of 0.09 g. The mass portion 4b is a cylinder with a radius of 7.5 mm and a height of 3 mm, and has a mass of 0.6 g. The sound insulation structure 1 of this example has an overall thickness of 10 mm and an areal density of 3.57 kg / m 2The region (frequency range) of this sound insulation structure 1 where the effective mass density is negative and the effective bulk modulus is positive in the frequency band of 100 Hz to 2 kHz under room temperature atmosphere is 280 Hz to 505 Hz. Therefore, the difference between the highest frequency and the lowest frequency in this region is 225 Hz. When the maximum value of the transmission loss in the region (280 Hz to 505 Hz) where the effective mass density is negative and the effective bulk modulus is positive in the frequency band of 100 Hz to 2 kHz under room temperature atmosphere is compared with the theoretical value of the sound insulation calculated based on the mass law of the sound insulation structure 1 of this embodiment, the increase was 14.1 [dB]. The maximum value of the transmission loss in the above-mentioned region (280 Hz to 505 Hz) was exhibited at 295 Hz.

[0055] [Example 3] The sound insulation structure 1 of Example 3 of the present invention has substantially the same structure as the first embodiment shown in Figures 1 and 2. The base portion 2 and the peripheral wall portion 3 of this example have a Young's modulus of dynamic storage elastic modulus (E') of 100 MPa at 23°C and a frequency of 1 Hz, and a density of 1390 kg / m 3 The spring portion 4a of the weight portion 4 in this embodiment has a Young's modulus of 1 MPa in dynamic storage elasticity (E') at 23°C and a frequency of 1 Hz, and a density of 1167 kg / m 3 The sound insulation structure 1 of this embodiment is made of silicone rubber with a Poisson's ratio of 0.49 and a loss tangent of 0.17 as a Damping (Loss Factor), and is a cylinder with a radius of 3 mm and a height of 3 mm. The spring portion 4a has a mass of 0.09 g. The mass portion 4b has the same configuration as the mass portion 4b of Example 1. The sound insulation structure 1 of this embodiment has an overall thickness of 10 mm and an areal density of 3.63 kg / m 2The region (frequency range) of this sound insulation structure 1 where the effective mass density is negative and the effective bulk modulus is positive in the frequency band of 100 Hz to 2 kHz under room temperature atmosphere is 460 Hz to 1340 Hz. Therefore, the difference between the highest frequency and the lowest frequency in this region is 880 Hz. When the maximum value of the transmission loss in the region (460 Hz to 1340 Hz) where the effective mass density is negative and the effective bulk modulus is positive in the frequency band of 100 Hz to 2 kHz under room temperature atmosphere is compared with the theoretical value of the sound insulation calculated based on the mass law of the sound insulation structure 1 of this embodiment, the increase was 13.8 [dB]. The maximum value of the transmission loss in the above-mentioned region (460 Hz to 1340 Hz) was exhibited at 740 Hz.

[0056] [Example 4] The sound insulation structure 1 of Example 4 of the present invention shown in FIG. 15 has substantially the same structure as the first embodiment shown in FIGS. 1 and 2. The sound insulation structure 1 of this example differs from the sound insulation structure 1 of Example 1 only in the height of the peripheral wall portion 3 in the direction perpendicular to the base portion 2, and the other configuration is the same as the sound insulation structure 1 of Example 1. The base portion 2 and the peripheral wall portion 3 of this example are made of EPDM, the same as the base portion 2 and the peripheral wall portion 3 of Example 1, but the height of the peripheral wall portion 3 of this example in the direction perpendicular to the base portion 2 is 14.5 mm. The spring portion 4a and the mass portion 4b of the weight portion 4 of this example have the same configuration as the spring portion 4a and the mass portion 4b of the weight portion 4 of Example 1. The sound insulation structure 1 of this example has an overall thickness of 15 mm and an areal density of 3.85 kg / m 2 The region (frequency range) of this sound insulation structure 1 where the effective mass density is negative and the effective bulk modulus is positive in the frequency band of 100 Hz to 2 kHz under room temperature atmosphere is 230 Hz to 520 Hz. Therefore, the difference between the highest frequency and the lowest frequency in this region is 290 Hz. When the maximum value of the transmission loss in the region (230 Hz to 520 Hz) where the effective mass density is negative and the effective bulk modulus is positive in the frequency band of 100 Hz to 2 kHz under room temperature atmosphere is compared with the theoretical value of the sound insulation calculated based on the mass law of the sound insulation structure 1 of this embodiment, the increase was 17.0 [dB]. The maximum value of the transmission loss in the above-mentioned region (230 Hz to 520 Hz) was exhibited at 270 Hz.

[0057] [Comparative Example 1] 16 has a base portion 2 and a peripheral wall portion 3 having the same configurations as those of the base portion 2 and the peripheral wall portion 3 of Example 1, but does not have a weight portion 4. The sound insulation structure 11 of this comparative example has an overall thickness of 10 mm and an areal density of 2.43 kg / m 2 The region (frequency range) of this sound insulation structure 11 where the effective mass density is negative and the effective bulk modulus is positive in the frequency band of 100 Hz to 2 kHz under room temperature atmosphere is 130 Hz to 170 Hz. Therefore, the difference between the highest frequency and the lowest frequency in this region is 40 Hz. When the maximum value of the transmission loss in the region (130 Hz to 170 Hz) where the effective mass density is negative and the effective bulk modulus is positive in the frequency band of 100 Hz to 2 kHz under room temperature atmosphere is compared with the theoretical value of the sound insulation calculated based on the mass law of the sound insulation structure 11 of this comparative example, the increase was 13.0 [dB]. The maximum value of the transmission loss in the above-mentioned region (130 Hz to 170 Hz) was exhibited at 125 Hz.

[0058] [Comparative Example 2] The sound insulation structure 12 of Comparative Example 2 shown in FIG. 17 has a base portion 2 and a peripheral wall portion 3 of the same configuration as the base portion 2 and the peripheral wall portion 3 of Example 1, but the configuration of the weight portion 4 is different from that of Example 1. The spring portion 4a and the mass portion 4b of the weight portion 4 of this comparative example are both made of silicone rubber, the same as the spring portion 4a of Example 1. The spring portion 4a is a cylinder with a radius of 3 mm, a height of 3 mm, and a mass of 0.09 g. The mass portion 4b is a cylinder with a radius of 1.5 mm, a height of 3 mm, and a mass of 0.03 g. The overall thickness of the sound insulation structure 12 of this comparative example is 10 mm, and the surface density is 2.62 kg / m 2The region (frequency range) of this sound insulation structure 12 where the effective mass density is negative and the effective bulk modulus is positive in the frequency band of 100 Hz to 2 kHz under room temperature atmosphere is 375 Hz to 575 Hz. Therefore, the difference between the highest frequency and the lowest frequency in this region is 200 Hz. When the maximum value of the transmission loss in the region (375 Hz to 575 Hz) where the effective mass density is negative and the effective bulk modulus is positive in the frequency band of 100 Hz to 2 kHz under room temperature atmosphere is compared with the theoretical value of the sound insulation calculated based on the mass law of the sound insulation structure 12 of this comparative example, the increase was 11.0 [dB]. The maximum value of the transmission loss in the above-mentioned region (375 Hz to 575 Hz) was exhibited at 405 Hz.

[0059] [result] Comparing the above-mentioned Examples 1 to 4 of the present invention with Comparative Examples 1 and 2, it is found that the sound insulation effect is improved by the sound insulation structure 1 of the present invention. And, the sound insulation structure 1 of Examples 1 to 4 of the present invention can obtain a sound insulation effect significantly greater than the theoretical value based on the mass law. Furthermore, compared to Comparative Example 1, which has a sound insulation structure 11 without a weight portion 4 and has a narrow region in which the effective mass density is negative and the effective bulk modulus is positive in the frequency band of 100 Hz to 2 kHz under room temperature atmosphere, and Comparative Example 2, in which the mass portion 4b located on the side opposite to the side attached to the base 2 is smaller in size and mass than the spring portion 4a located on the side attached to the base 2 of the weight portion 4, the sound insulation structure 1 of Examples 1 to 4 of the present invention exhibits good sound insulation. Also, comparing Example 1 with Example 3, it is found that even if the elasticity of the base 2 and the peripheral wall portion 3 is somewhat different, almost the same sound insulation can be obtained. And, comparing Example 1 with Example 4, it is found that a higher sound insulation can be obtained when the height of the peripheral wall portion 3 is high and the interval between the member to which the sound insulation structure 1 is attached and the base 2 is large.

[0060] The present invention may have the following configuration. [1] A hollow frame structure having an opening at one end and a weight portion located inside the hollow portion of the frame structure, The frame structure has a base portion facing the opening portion and a peripheral wall portion extending from the base portion toward the opening portion, One of the weight portions is disposed on one of the frame structures, the weight portion is attached to the base of the frame structure and extends in a direction toward the opening, and the weight portion is surrounded by the base and the peripheral wall except for a portion facing the opening, a height of the peripheral wall portion in a direction from the base of the frame structure toward the opening portion is greater than a height of the weight portion; the weight portion constitutes a spring mass resonator having a spring portion having elasticity and located on a side attached to the base, and a mass portion having a larger mass than the spring portion and located on a side opposite to the side attached to the base of the weight portion, A sound-proofing structure characterized in that, in the frequency band of 100 Hz or more and 2 kHz or less, there is at least one region in which the effective mass density is negative and the effective bulk modulus is positive, and the difference between the maximum and minimum frequencies in said region is 200 Hz or more. [2] The frame structure is a cylindrical or rectangular tube having an elastic sheet-like base and a peripheral wall portion erected on the base, one end of the hollow portion is closed by the base and the other end is open, The sound-proofing structure according to [1], wherein the weight portion is provided on the same surface of the base as the surface on which the peripheral wall portion is provided. [3] The sound insulation structure according to [1] or [2], wherein in the frequency band of 100 Hz or more and 2 kHz or less, the difference between the highest frequency and the lowest frequency in the region where the effective mass density is negative and the effective bulk modulus is positive is 500 Hz or less. [4] The effective mass density in the above region is -5000kg / m 3 More than 0kg / m 3 A sound insulation structure according to any one of [1] to [3] below. [5] The sound-proofing structure according to any one of [1] to [4], wherein the effective bulk modulus in the region is 0 Pa or more and 500,000 Pa or less. [6] The sound-proofing structure described in any of [1] to [5], wherein the base portion, the peripheral wall portion and the spring portion are all made of either a material that has no energy elasticity but has rubber elasticity, a material that has no rubber elasticity but has energy elasticity, or a material that has both rubber elasticity and energy elasticity. [7] The sound-proofing structure according to any one of [1] to [6], wherein the base portion, the peripheral wall portion and the spring portion all have a dynamic storage modulus of 0.01 MPa or more and 100 MPa or less at 23°C and at a frequency of 1 Hz to 1000 Hz. [8] The sound-proofing structure according to any one of [1] to [7], wherein the base portion, the peripheral wall portion and the spring portion all have a loss tangent of 0.01 or more and 0.50 or less at 23°C and a frequency of 1 Hz to 1000 Hz. [9] The sound-proofing structure according to any one of [1] to [8], wherein the mass portion of the weight portion has a larger volume than the spring portion.

[10] A sound-proofing structure according to any one of [1] to [9], wherein the mass portion of the weight portion is made of a material having a higher density than the spring portion.

[11] The sound-proofing structure according to any one of [1] to

[10] , wherein the thickness of the peripheral wall portion is 0.5 mm or more and 5.0 mm or less.

[12] The sound-proofing structure according to

[11] , wherein the thickness of the peripheral wall portion is 1.0 mm or more and 3.0 mm or less.

[13] The sound-proofing structure according to any one of [1] to

[12] , wherein the thickness of the base is 0.1 mm or more and 3.0 mm or less.

[14] A sound-proofing structure according to any one of [1] to

[13] , wherein the height in a direction perpendicular to the base is 5 mm or more and 20 mm or less.

[15] A sound-proofing structure according to any one of [1] to

[14] , wherein the height of the peripheral wall portion extending in a direction perpendicular to the base portion is 5 mm or more and 20 mm or less.

[16] The sound-proofing structure according to

[15] , wherein the height of the peripheral wall portion extending in a direction perpendicular to the base portion is 10 mm or more and 20 mm or less.

[17] A sound-proofing structure according to any one of [1] to

[16] , wherein the height of the weight portion extending in a direction perpendicular to the base portion is 1 mm or more.

[18] The sound-proofing structure according to any one of [1] to

[17] , wherein the base portion has a Durometer A hardness of 30 or more, and the peripheral wall portion has a Durometer A hardness of 1 or more and 90 or less.

[19] A sound-proofing structure according to any one of [1] to

[18] , wherein a plurality of the frame structures are arranged side by side in a plane, and each of the frame structures has one weight portion arranged thereon.

[20] The sound-proofing structure described in

[19] , wherein the same weight portion is arranged in all of the frame structures.

[21] The sound-proofing structure according to

[19] , wherein some of the frame structures are provided with weight portions having a different configuration from the weight portions provided with the other frame structures.

[22] A sound-proofing structure described in any of

[19] to

[21] , wherein the peripheral wall portion includes a plurality of first wall portions extending in a direction perpendicular to the base and extending in a first direction parallel to the base, and a plurality of second wall portions extending in a direction perpendicular to the base and extending in a second direction perpendicular to the first direction.

[23] The planar area of ​​the hollow portion of each of the frame structures is 100 mm 2 More than 1000mm 2 The sound insulation structure according to any one of

[19] to

[22] , which is as follows:

[24] Area 1000cm 2 The sound insulation structure according to any one of

[19] to

[23] , wherein 10 to 1,000 of the frame structures are provided per sound insulation structure.

[25] Area 1000cm 2

[24] The sound insulation structure according to

[24] , wherein 50 to 500 of the frame structures are provided per unit area. [Explanation of symbols]

[0061] 1,7,11,12 Sound insulation structure 2 base 3 Peripheral wall part 3a 1st wall 3b 2nd wall part 4 Weight part 4a Spring part 4b Mass section (mass section) 5 Hollow part 5a Opening part 6 Frame structure 8 intervals 9 Connection piece

Claims

1. The present invention includes a hollow frame structure having an opening at one end, and a weight portion located inside the hollow portion of the frame structure, The frame structure has a base portion facing the opening portion and a peripheral wall portion extending from the base portion toward the opening portion, One of the weight portions is disposed on one of the frame structures, the weight portion is attached to the base of the frame structure and extends in a direction toward the opening, and the weight portion is surrounded by the base and the peripheral wall portion except for a portion facing the opening, a height of the peripheral wall portion in a direction from the base of the frame structure toward the opening portion is greater than a height of the weight portion; the weight portion constitutes a spring mass resonator having a spring portion having elasticity and located on a side attached to the base, and a mass portion having a larger mass than the spring portion and located on a side opposite to the side attached to the base of the weight portion, A sound-proofing structure, characterized in that in a frequency band of 100 Hz or more and 2 kHz or less, there is at least one region in which the effective mass density is negative and the effective bulk modulus is positive, and the difference between the maximum frequency and the minimum frequency in the region is 200 Hz or more.

2. The frame structure is a cylindrical or rectangular tube having an elastic sheet-like base and a peripheral wall portion standing on the base, one end of the hollow portion is closed by the base and the other end is open, The sound insulation structure according to claim 1 , wherein the weight portion is provided upright on the same surface of the base as the peripheral wall portion.

3. 3. The sound insulation structure according to claim 1, wherein in a frequency band of 100 Hz or more and 2 kHz or less, a difference between a maximum frequency and a minimum frequency in the region in which the effective mass density is negative and the effective bulk modulus is positive is 500 Hz or less.

4. The effective mass density in said region is -5000 kg / m 3 More than 0kg / m 3 3. The sound insulation structure according to claim 1 or 2, wherein:

5. 3. The sound insulation structure according to claim 1, wherein the effective bulk modulus in the region is 0 Pa or more and 500,000 Pa or less.

6. 3. The sound-proofing structure according to claim 1 or 2, wherein the base portion, the peripheral wall portion and the spring portion are all made of any one of a material that has no energy elasticity but has rubber elasticity, a material that has no rubber elasticity but has energy elasticity, and a material that has both rubber elasticity and energy elasticity.

7. 3. The sound insulation structure according to claim 1, wherein the base portion, the peripheral wall portion and the spring portion all have a dynamic storage modulus of 0.01 MPa or more and 100 MPa or less at 23° C. and at a frequency of 1 Hz to 1000 Hz.

8. 8. The sound insulation structure according to claim 7, wherein the base portion, the peripheral wall portion and the spring portion all have a loss tangent of 0.01 or more and 0.50 or less at 23° C. and a frequency range of 1 Hz to 1000 Hz.

9. The sound insulation structure according to claim 1 , wherein the mass portion of the weight portion is larger in volume than the spring portion.

10. The sound-proof structure according to claim 1 , wherein the mass portion of the weight portion is made of a material having a higher density than the spring portion.

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