Soundproof structure

Abstract

To provide a thin and light-weight soundproof structure that can provide sufficient sound insulating properties, and can be easily and stably mounted on a panel of an automobile having a curved surface or irregularities or an automobile member mounted on the panel.SOLUTION: A soundproof structure 1a is arranged at part of a position at which a space 12 in which a front wheel tire 11 of an automobile is accommodated and a cabin 13 are partitioned from each other, and has a film part 2 having elasticity, support wall parts 3 erected on the film part 2 and having elasticity, and weight parts 4 erected on the film part 2. The film part 2 is divided into a plurality of sections by the support wall parts 3, and the weight parts 4 are located inside all the sections or some of the sections. One weight part 4 is arranged in one section. The height of the support wall part 3 extending in a direction orthogonal to the film part 2 is larger than the height of the weight part 4 extending in the direction orthogonal to the film part 2. Each of the weight parts 4 forms a spring-mass resonator having a spring part 4a having elasticity and a mass part 4b having a larger mass than the spring part 4a.SELECTED DRAWING: Figure 2

Description

[Technical Field]

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

[0002] In recent years, there has been a demand for reducing noise in the interior of an automobile to provide a quiet and comfortable space for occupants by blocking out noises such as road noise, tire pattern noise, wind noise, and engine noise. Therefore, there is a demand for means for suppressing the propagation of noise and vibration from the outside of the automobile to the interior, and also for the propagation of noise and vibration from the outside of the passenger compartment to the passenger compartment within the automobile, i.e., for members with high soundproofing properties. In recent years, there has been a demand for lightweight soundproofing members to improve the energy efficiency of automobiles. Examples of soundproofing structures installed in automobiles and the like are disclosed in Patent Documents 1 to 9.

[0003] Patent Documents 1 and 2 disclose automotive dash silencers (also called dash insulators). These dash silencers are laminated on the dash panel (dashboard) located at the boundary between the engine compartment and the passenger compartment, and suppress the intrusion of noise from the engine compartment into the passenger compartment. Dash silencers have a single-layer or multi-layer structure that includes felt or urethane foam as sound-absorbing materials.

[0004] Patent Document 3 discloses a floor carpet installation structure for a vehicle. This structure has a first floor carpet installed on a floor panel in front of a power supply unit, and a second floor carpet that covers the power supply unit from above and has higher sound insulation performance than the first floor carpet.

[0005] Patent Document 4 discloses a vehicle floor carpet. This floor carpet includes a spacer made of polypropylene foam and fitted into a recess in a floor panel, a sound-insulating layer laminated on the upper surface of the spacer, a resin sheet laminated on the upper surface of the sound-insulating layer, a sound-absorbing layer laminated on the upper surface of the resin sheet, and a surface material provided on the upper surface of the sound-absorbing layer. The spacer has a plurality of bottomed holes formed therein, which extend from the sound-insulating layer toward the lower part of the floor panel and are closed on the floor panel side and have openings on the sound-insulating layer side.

[0006] Patent Document 5 discloses an automobile floor covering. This floor covering comprises a floor carpet laid on the floor panel of the automobile and a shock absorber laminated on the back surface of the floor carpet, the shock absorber being formed by assembling and molding a large number of cylindrical soft resin particles.

[0007] The invention described in Patent Document 6 is an acoustic damping panel comprising a rigid frame divided into a plurality of individual cells, a sheet of flexible material, and a plurality of weights, each weight being fixed to the sheet of flexible material so that each cell is provided with a weight, and the attenuated sound is controlled by appropriate selection of the mass of the weights.

[0008] In the invention described in Patent Document 7, in a soundproofing material comprising an elastic sheet and a support portion that holds the sheet and divides the sheet into partitions, the relationship between the rigidity of the sheet in the partitions and the surface density of the sheet is specified.

[0009] The sound-proofing material of the invention described in Patent Document 8 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 that connects the weight portion to the substrate portion, and is configured so that, in a projection view seen 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.

[0010] The vibration reduction device of the invention described in Patent Document 9 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 respective natural frequencies, blocking vibrations transmitted from the vehicle body through the frame. [Prior art documents] [Patent documents]

[0011] [Patent Document 1] Japanese Patent Application Laid-Open No. 2007-210381 [Patent Document 2] Japanese Patent Application Publication No. 2018-012353 [Patent Document 3] Patent No. 7119364 [Patent Document 4] Patent No. 4714183 [Patent Document 5] Patent No. 4437662 [Patent Document 6] Japanese Patent Application Laid-Open No. 2005-250474 [Patent Document 7] Patent No. 6879369 [Patent Document 8] Patent Publication No. 2021-152584 [Patent Document 9] Japanese Patent Publication No. 2020-91481 Summary of the Invention [Problem to be solved by the invention]

[0012] The dash silencers described in Patent Documents 1 and 2 are unable to sufficiently reduce noise entering the vehicle cabin. In particular, road noise and tire pattern noise transmitted from the tires in contact with the ground into the vehicle cabin are large, which may prevent the provision of a quiet and comfortable space for the occupants.

[0013] The vehicle floor carpet described in Patent Document 3 can reduce the transmission of noise from the power supply unit on the floor panel by using a second floor carpet, but it cannot block road noise or tire pattern noise transmitted into the vehicle interior from the tires in contact with the ground. In addition, the floor carpet in Patent Document 3 does not have a special structure for soundproofing.

[0014] The vehicle floor carpet described in Patent Document 4 has sound-insulating and sound-absorbing layers made of felt, and bottomed holes in spacers made of polypropylene foam. While the sound-insulating and sound-absorbing layers provide soundproofing throughout the entire floor carpet, the bottomed holes in the spacers are located primarily near the center of the floor carpet, rather than the edges, and therefore are unable to effectively block road noise and tire pattern noise transmitted into the vehicle cabin from tires that are located near the edges of the floor carpet and in contact with the ground. Furthermore, the felt and bottomed holes alone do not provide a significant soundproofing effect.

[0015] The floor covering described in Patent Document 5 has shock absorbers, but does not provide sound insulation. Therefore, it cannot efficiently block road noise and tire pattern noise transmitted from the tires on the ground into the vehicle interior. Furthermore, simply collectively molding a large number of cylindrical soft resin particles does not provide a significant soundproofing effect.

[0016] The acoustic damping panel described in Patent Document 6 has an inflexible, rigid frame, and vibrations are transmitted to the seat via this rigid frame, which may result in insufficient sound insulation. Furthermore, if the support surface on which the rigid frame is placed is curved or uneven, the acoustic damping panel may not be stably supported. In particular, since many components of typical automobiles, such as panels, have curved or uneven surfaces, it is difficult to easily use the acoustic damping panel described in Patent Document 6 as an automotive soundproofing material. Furthermore, rigid frames have a large mass, and the increased mass of the soundproofing material in an automobile poses a problem.

[0017] The soundproofing material described in Patent Document 7 has a high support portion, i.e., a height extending from the seat in a direction perpendicular to the seat, preferably 25 mm or more. In order to stably support the seat with such a high support portion, the support portion preferably has rigidity. As a result, vibrations may be transmitted through the support portion, which may result in insufficient sound insulation. It may also be difficult to mount the soundproofing material on curved or uneven surfaces, such as automobile panels. Furthermore, such high support portions result in the overall size and weight of the soundproofing material. When mounted on automobile panels or other components, the soundproofing material may occupy a large amount of space inside the automobile, reducing space efficiency, interfering with the installation of other components, and becoming a nuisance to passengers.

[0018] The sound-insulating material described in Patent Document 8 has a resonating section, which is the functional part that provides sound insulation, exposed and not covered by a supporting wall, etc., and if this resonating section comes into contact with other members or the human body, there is a risk that the sound-insulating properties will be reduced or changed. Therefore, it is necessary to provide a large space around the resonating section, which reduces space efficiency.

[0019] The vibration reduction device described in Patent Document 9 does not have a membrane portion, but consists of multiple vibrators and a frame connecting them. Therefore, like the sound-insulating material described in Patent Document 8, the vibrators, which are the functional components that provide the sound-insulating effect, are exposed, and if other components or the human body come into contact with these vibrators, the sound-insulating properties may be reduced or changed. Furthermore, the frame must be rigid to ensure a minimum structural strength for the vibration reduction device. As a result, vibrations are transmitted through the frame, which may result in insufficient sound insulation. Furthermore, it is difficult to mount the vibration reduction device described in Patent Document 9 on components, such as automobile panels, that have curved or uneven surfaces.

[0020] The structures described in Patent Documents 1 to 5 have one objective of making the interior of an automobile quieter, but are not intended to prevent noise from tires in contact with the ground from entering the interior of the vehicle. Furthermore, none of the configurations described in Patent Documents 1 to 9 provide sufficient sound insulation against noise entering the interior of the vehicle, and a soundproofing structure with better sound insulation is desired.

[0021] Therefore, an object of the present invention is to provide a thin and lightweight soundproof structure that can provide sufficient soundproofing and can be easily and stably mounted on a curved or uneven automobile panel or automobile component, and that has particularly good soundproofing properties against noise in the low frequency range of 1000 Hz or less that enters the vehicle interior from tires in contact with the ground. [Means for solving the problem]

[0022] The soundproofing structure of the present invention is arranged at least in part at a position separating the space in an automobile that accommodates front wheel tires from the passenger compartment, and comprises an elastic membrane portion, an elastic support wall portion standing on the membrane portion, and a weight portion standing on the membrane portion, the membrane portion being divided into a plurality of compartments by the support wall portions, the weight portion being located inside all of the plurality of compartments or inside some of the plurality of compartments, each of the weight portions being located in one of the compartments, the height of the support wall portion extending in a direction perpendicular to the membrane portion being greater than the height of the weight portion extending in a direction perpendicular to the membrane portion, and each of the weight portions constituting a spring-mass resonator having an elastic spring portion and a mass portion having a mass greater than that of the spring portion. The term "elasticity" used here refers to the property of a solid substance that has been deformed by an external force and then returns 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" if it has at least one of energy elasticity and rubber elasticity (entropy elasticity). The membrane portion, the support wall portion and the spring portion may all be made of 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. The film portion, the support wall portion, and the spring portion may all have a dynamic storage modulus of 0.01 MPa or more and 100 MPa or less at 23° C. and a frequency of 1 Hz to 1000 Hz. The film portion, the support wall portion, and the spring portion may 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. Specifically, the elasticity of the membrane, supporting wall, and spring portions is evaluated by measuring frequency dependency in tension or compression mode with a dynamic viscoelasticity measuring device in accordance with JIS K 7244, and determining a master curve based on 23° C., and the dynamic storage modulus (E') is 0.01 MPa or more and 100 MPa or less at 23° C. and frequencies of 1 Hz to 1000 Hz. Even more preferably, the membrane and supporting wall portions each have a dynamic storage modulus (E') of 0.05 MPa or more and 50 MPa or less at 23° C. and frequencies of 1 Hz to 1000 Hz, and a loss tangent of 0.05 to 0.45 at 23° C. and frequencies of 1 Hz to 1000 Hz. The spring portion may be located on the side of the weight portion attached to the membrane portion, and the mass portion may be located on the opposite side of the weight portion from the side attached to the membrane portion. The mass portion may have a larger volume than the spring portion. The mass portion may be made of a material having a higher density than the spring portion. Another soundproofing structure of the present invention is arranged in at least a portion of a position of an automobile separating a space that accommodates front wheel tires from the passenger compartment, and comprises an elastic membrane portion, an elastic support wall portion standing on the membrane portion, and a weight portion standing on the membrane portion, the membrane portion being divided into a plurality of compartments by the support wall portions, the weight portion being located inside all of the plurality of compartments or inside some of the plurality of compartments, each of the weight portions being located in one of the compartments, the height of the support wall portion extending in a direction perpendicular to the membrane portion being greater than the height of the weight portion extending in a direction perpendicular to the membrane portion, and the membrane portion acting as a spring portion and the weight portion acting as a mass portion constituting a spring-mass resonator. Both the membrane portion and the support wall portion may be made of 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. The membrane portion and the supporting wall portion may both have a dynamic storage modulus of 0.01 MPa or more and 100 MPa or less at a frequency of 1 Hz to 1000 Hz at 23° C. Furthermore, the membrane portion and the supporting wall portion may both have a loss tangent of 0.01 or more and 0.50 or less at a frequency of 1 Hz to 1000 Hz at 23° C. More preferably, the membrane portion and the supporting wall portion may both have a dynamic storage modulus (E') of 0.05 MPa or more and 50 MPa or less at a frequency of 1 Hz to 1000 Hz at 23° C., and a loss tangent of 0.05 or more and 0.45 or less at a frequency of 1 Hz to 1000 Hz at 23° C. In the soundproofing structure of the present invention and another soundproofing structure, the support wall portion may include a plurality of first wall portions extending in a direction perpendicular to the membrane portion and extending in a first direction parallel to the membrane portion, and a plurality of second wall portions extending in a direction perpendicular to the membrane portion and extending in a second direction perpendicular to the first direction. The support wall portion may be cylindrical with a circular, elliptical or oval cross-sectional shape that defines each of the compartments, or may be rectangular with a polygonal cross-sectional shape that defines each of the compartments, specifically a square, regular pentagon or regular hexagonal cross-sectional shape. The area of ​​each of the compartments is 100 mm 2 More than 1000mm 2 It may be the following: The area of ​​the membrane is 1000 cm 2 More preferably, the membrane portion has an area of ​​1000 cm or more and 1000 or less of the compartments. 2 There may be 50 to 500 of the compartments per unit area. The support wall portion may have a thickness of 0.5 mm or more and 5.0 mm or less. More preferably, the support wall portion may have a thickness of 1.0 mm or more and 3.0 mm or less. The membrane portion may have a thickness of 0.1 mm or more and 3.0 mm or less. The height in the direction perpendicular to the film portion may be 5 mm or more and 20 mm or less. The height of the support wall portion extending from the film portion in a direction perpendicular to the film portion may be 5 mm or more and 20 mm or less, and the height may vary in parts. The height of the weight portion extending from the film portion in a direction perpendicular to the film portion may be 1 mm or more. The film portion may have a durometer A hardness of 50 or more, and the support 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. The soundproofing structure may be formed so as to form part of a floor carpet laid from the floor surface of the vehicle compartment to a position that partially covers the space, or may be sandwiched between the floor carpet and a panel that partially covers the space or an automotive component placed on the panel. The acoustic structure may be located inside the electric vehicle. [Effects of the Invention]

[0023] According to the present invention, it is possible to provide a thin and lightweight soundproof structure that can provide sufficient soundproofing and can be easily and stably mounted on a curved or uneven automobile panel or automobile component, and that has good soundproofing properties, particularly in the low frequency range of 1000 Hz or less. [Brief explanation of the drawings]

[0024] [Figure 1] 1 is a side view of an automobile provided with a soundproof structure according to a first embodiment of the present invention. [Figure 2] FIG. 2 is an enlarged side view showing the main parts of the interior of the automobile shown in FIG. [Figure 3] 1 is a perspective view of a floor carpet including a soundproof structure according to a first embodiment of the present invention. [Figure 4] FIG. 4 is a schematic cross-sectional view of the floor carpet shown in FIG. 3. [Figure 5] 1A is a perspective view of a soundproof structure of the present invention, and FIG. 1B is a cross-sectional view taken along line AA thereof. [Figure 6] 6(A) is an exploded perspective view of one section of the soundproof structure shown in FIG. 5, and FIG. 6(B) is an exploded front view thereof. [Figure 7] FIG. 5 is a cross-sectional view showing a further enlarged view of a joint portion of the floor carpet shown in FIG. [Figure 8] FIG. 2 is a side view of an automobile provided with a soundproof structure according to a second embodiment of the present invention. [Figure 9] FIG. 9 is an enlarged side view showing the main parts of the interior of the automobile shown in FIG. 8. [Figure 10] FIG. 1A is a perspective view of another example of the soundproof structure of the present invention, and FIG. 1B is a cross-sectional view taken along line AA thereof. [Figure 11] FIG. 11 is a schematic cross-sectional view of a floor carpet including the soundproof structure shown in FIG. [Figure 12] 1A is a perspective view of a modified example of the soundproof structure of the present invention, and FIG. 1B is a cross-sectional view taken along line AA thereof. [Figure 13]FIG. 1(A) is a plan view schematically showing one section of a soundproof structure of the present invention, and FIG. 1(B) is a plan view schematically showing a plurality of sections. [Figure 14] FIG. 1(A) is a plan view schematically showing one section of another example of a soundproof structure of the present invention, and FIG. 1(B) is a plan view schematically showing a plurality of sections. [Figure 15] Graphs (A) to (C) show the sound insulation properties of Examples 1 to 4 of the present invention and Comparative Examples 1 to 4. [Figure 16] Graphs (A) to (C) show the sound insulation properties of Examples 1 and 5 to 8 of the present invention and Comparative Example 3. [Figure 17] Graphs (A) to (C) show the sound insulation properties of Examples 8 to 11 of the present invention. [Figure 18] Graphs (A) and (B) show the sound insulation properties of Examples 1 and 12 to 14 of the present invention and Comparative Examples 5 and 6. [Figure 19] 3A is a perspective view of a soundproof structure according to a third embodiment of the present invention, and FIG. 3B is a cross-sectional view taken along line AA thereof. [Figure 20] 6A is a perspective view of a soundproof structure according to a sixth embodiment of the present invention, and FIG. 6B is a cross-sectional view taken along line AA thereof. [Figure 21] FIG. 13 is a cross-sectional view of a soundproof structure according to a tenth embodiment of the present invention. [Figure 22] 11(A) is a perspective view of a soundproof structure according to an eleventh embodiment of the present invention, and FIG. 11(B) is a cross-sectional view taken along line BB thereof. [Figure 23] 1A is a perspective view of the soundproof structure of Comparative Example 3, and FIG. 1B is a cross-sectional view taken along line AA thereof. DETAILED DESCRIPTION OF THE INVENTION

[0025] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. [First embodiment] FIG. 1 shows a side view of an automobile equipped with a soundproof structure 1a according to a first embodiment of the present invention, and FIG. 2 is an enlarged side view showing a main portion of the interior of the automobile. FIG. 3 is a perspective view of a floor carpet 1 including the soundproof structure 1a according to this embodiment, and FIG. 4 is a schematic cross-sectional view thereof. In this automobile, the soundproof structure 1a according to the present invention is arranged so as to overlap a panel 14 provided at the boundary between a space 12 in which a front tire 11 is housed and a passenger compartment 13, or an automobile component (e.g., a dash insulator 10) placed on the panel 14. Specifically, the soundproof structure 1a according to this embodiment is formed so as to constitute a part of the floor carpet 1. The floor carpet 1 is laid from the floor surface of the passenger compartment 13 to a position that partially covers the space 12 in which the front tire 11 is housed. The soundproof structure 1a is incorporated into the floor carpet 1 at a portion on the front side of the vehicle, in a position that partially covers the space 12 in which the front tire 11 is housed. As shown schematically in Figure 2, the soundproofing structure 1a is provided at a position where the feet of an occupant P seated in a seat 15 are placed, or at a position further forward. Note that the panel referred to here is a general term for plate-like members located inside an automobile, including parts of the frame, chassis, etc., and the automobile member referred to here is a general term for members placed on the panel, such as the dash insulator 10.

[0026] The floor carpet 1 of this embodiment is a floor carpet having a similar structure to a conventional floor carpet, with a soundproof structure 1a incorporated into the floor carpet. The specific structure of this soundproof structure 1a is shown in FIGS. 5 and 6. FIG. 5(A) is a perspective view of the soundproof structure 1a, and FIG. 5(B) is a cross-sectional view taken along line AA in FIG. 5(A) and inverted. FIG. 6(A) is an exploded perspective view of one section of the soundproof structure 1a shown in FIG. 5, and FIG. 6(B) is an exploded front view of the soundproof structure 1a. The soundproof structure 1a includes an elastic sheet-like film portion 2, an elastic support wall portion 3 extending substantially perpendicularly from the film portion 2, and a weight portion 4 extending substantially perpendicularly from the film portion 2. The film portion 2 may be joined to and integrated with the floor carpet body. Alternatively, the film portion 2 may be a part of a floor carpet having a similar structure to a conventional floor carpet body, and the soundproof structure 1a may be formed by providing the support wall portion 3 and the weight portion 4 to a portion of the floor carpet body (the film portion 2). The membrane 2 is divided into multiple compartments (unit structures) 5 by support walls 3. A weight 4 is located in each of the compartments 5, or in some of the compartments 5. Each compartment 5 with a weight 4 located therein has one weight 4 located therein. The height H1 of the support walls 3 extending from the membrane 2 in a direction perpendicular to the membrane 2 is greater than the height H2 of the weight 4 extending from the membrane 2 in a direction perpendicular to the membrane 2. Each weight 4 constitutes a spring-mass resonator having an elastic spring 4a and a mass 4b having a greater mass than the spring 4a. Elasticity here refers to the property of a solid material that is deformed by an external force and returns to its original shape when the external force is removed, and includes energy elasticity and rubber elasticity (entropy elasticity). Here, the term "elastic" refers to the presence of at least one of energy elasticity and rubber elasticity (entropy elasticity). The configuration shown in Figures 5 and 6 can be employed not only in the soundproof structure 1a of the first embodiment shown in Figures 1 to 4, but also in the soundproof structure 6 of the second embodiment shown in Figures 8 and 9, which will be described later. Therefore, the soundproof structure shown in Figures 5 and 6 is given both the reference numeral 1a and the reference numeral 6.

[0027] The support wall 3 of the soundproof structure 1a of this embodiment includes a plurality of first walls 3a extending in a first direction D1 parallel to the membrane 2 and a plurality of second walls 3b extending in a second direction D2 perpendicular to the first direction D1. Specifically, the plurality of first walls 3a are arranged in parallel, and the plurality of second walls 3b are arranged in parallel, with the first walls 3a and the second walls 3b being integrated at their intersections. The plurality of first walls 3a and the plurality of second walls 3b thus form a lattice structure, and a plurality of compartments 5, each having a square planar shape and partitioned by the first walls 3a and the second walls 3b, are arranged in a matrix. In other words, the support wall 3 is structured by arranging a plurality of rectangular tubes, each with a square cross section, defining each compartment 5. The support wall 3 is preferably made of a flexible material such as rubber, elastomer, or resin foam. The flexible material referred to here is any of a material that has rubber elasticity but not energy elasticity, a material that has energy elasticity but not rubber elasticity, and a material that has both rubber elasticity and energy elasticity.

[0028] In this embodiment, the portion of the weight portion 4 attached to the membrane portion 2 is the spring portion 4a, and the portion opposite to the side attached to the membrane portion 2 is the mass portion 4b, which has a larger mass than the spring portion 4a. In the example shown in Figures 5 and 6, the spring portion 4a and the mass portion 4b have the same shape and dimensions but are made of different materials. The spring portion 4a is made of a flexible material, and the mass portion 4b is made of a material with a higher density than the material constituting the spring portion 4a. A spring-mass resonator is constructed in which the spring portion 4a functions as a spring and the mass portion 4b functions as a mass. Note that in addition to the spring portion 4a of the weight portion 4, the membrane portion 2 may also function as part of the spring of the spring-mass resonator. Furthermore, the air in the space surrounded by the membrane portion 2 and the support wall portion 3 may function as part of the spring of the spring-mass resonator (an 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.

[0029] In the soundproof structure 1a of this embodiment, the vibration of the membrane 2 is controlled by the action of a spring-mass resonator formed by the spring portion 4a and mass portion 4b of the weight portion 4. In particular, membrane vibration is significantly reduced in a specific frequency range (for example, frequencies below 1000 Hz, which are the main frequency bands of road noise and tire pattern noise in automobiles), resulting in a reduction in the sound radiated from the membrane 2 and a high level of sound insulation.

[0030] The section 5 of the soundproof structure 1a of this embodiment has a membrane part 2 with an area of ​​1000 cm 2 Preferably, 10 to 1000 compartments are provided per 1000 cm2 of the membrane part 2, and more preferably, 50 to 500 compartments are provided per 1000 cm2 of the membrane part 2. 2 By providing 10 or more sections 5 per membrane part 2, the entire soundproof structure 1a can be divided into a plurality of sections 5, and sound insulation effect can be exerted in each section, thereby improving the sound insulation of the entire soundproof structure 1a. 2 By limiting the number of pieces to 1,000 or less per section, the increase in the weight of the entire soundproof structure 1a can be suppressed. 2 More than 1000mm 2 Preferably, it is less than 200 mm 2 Over 800mm 2 It is more preferable that the area of ​​the planar shape of each of the sections 5 is 100 mm or less. 2 Therefore, it is easy to arrange the weight part 4 inside, and on the other hand, the area is 1000 mm 2Since the height of the weight 4 relative to the membrane 2 is less than or equal to 5 mm, the effect of the weight 4 on the membrane 2 is large, resulting in high sound insulation. The height of the entire soundproof structure 1a in the direction perpendicular to the membrane 2 is preferably 5 mm or more and 20 mm or less. When the height of the entire soundproof structure 1a is 5 mm or more, the weight 4 can have a sufficient height as a spring-mass resonator, and when the height is 20 mm or less, an increase in the weight of the entire soundproof structure 1a is suppressed. Note that each drawing shows each compartment 5 and supporting wall 3, etc., schematically, and the number and area of ​​compartments 5 and the height of supporting wall 3 may not be shown strictly accurately or may not be consistent across drawings. However, it is preferable that the number and area of ​​compartments 5 and the height of supporting wall 3 are appropriately designed so that they are within the aforementioned numerical ranges.

[0031] The film portion 2, supporting wall portion 3, and spring portion 4a of the soundproof structure 1a 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 frequency range of 1 Hz to 1000 Hz, and a loss tangent (tanδ) of 0.01 to 0.50 at 23° C. and a preferred dynamic storage modulus (E') of 0.05 MPa to 50 MPa at 23° C. and a loss tangent (tanδ) of 0.05 to 0.50 at 23° C. and a frequency range of 1 Hz to 1000 Hz. The dynamic storage modulus (E') and loss tangent (tanδ) are determined by creating a master curve based on 23° C. using a dynamic viscoelasticity tester. Since the dynamic storage modulus (E') at 23°C in the frequency range of 1 Hz to 1000 Hz is 0.01 MPa or more, sound insulation in the target frequency band is good, and the shape retention of the film portion 2 and the supporting wall portion 3 is good. Since the dynamic storage modulus (E') at 23°C in the frequency range of 1 Hz to 1000 Hz is 100 MPa or less, sound insulation in the target frequency band is good, and the soundproof structure 1a does not become rigid, making it easy to install. The film portion 2 and the supporting wall portion 3 may be made of the same material or different materials. It is preferable that the film portion 2 is also made of a flexible material, i.e., a material that has rubber elasticity but no energy elasticity, a material that has energy elasticity but no rubber elasticity, or a material that has both rubber elasticity and energy elasticity.

[0032] Since the weight 4 is attached to the film 2, it is preferable that the film 2 be a hard elastic film. The dynamic storage modulus (E') of the film 2 is preferably 15 MPa or more, and the thickness (film thickness) is preferably 0.1 mm to 3.0 mm, more preferably approximately 0.5 mm. When the film 2 is 0.1 mm or more, sufficient thickness is ensured, making it easy to handle. When the film 2 is 3.0 mm or less, the increase in the overall thickness and weight of the soundproof structure 1a is suppressed, and the entire soundproof structure 1a does not become too hard, making it easy to install. The material of the film 2 preferably has a durometer A hardness according to JIS K6253 of 50 or more, more preferably 70 or more. By setting the durometer A hardness of the film 2 within the above range, deterioration of the vibration of the film 2 is prevented, and sound insulation in the frequency band to be sound-insulated is improved. The rigidity (axial rigidity) k of the membrane part 2 is expressed as k = E' × A / L using the dynamic storage modulus E', the cross-sectional area A of the membrane part 2, and the thickness L of the membrane part 2. When the area of ​​the membrane part 2 to be evaluated for rigidity is 1000 cm 2 When the stiffness k is 10 6 N / mm or more 10 9 N / mm or less is preferable, and 3×10 6 N / mm or more 10 8 It is more preferable that the surface area of ​​the film portion 2 is 1000 cm or less. 2 When the stiffness is 10 6 When the surface area of ​​the film 2 is 1000 cm or more, the deterioration of the vibration of the film 2 can be suppressed, and the sound insulation performance in the frequency band to be insulated can be improved. 2 When the stiffness is 10 9 N / mm or less, the soundproof structure 1a becomes flexible and easy to install. The bending rigidity K of the film 2 is expressed as K=E'×I from the dynamic storage 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 film 2 and the width b of the film 2. 3 When the area of ​​the membrane part 2 to be evaluated is 1000 cm 2 When the bending stiffness K is 1N / mm 2 Over 10 5 N / mm 2 Preferably, it is 10 N / mm or less.2 5x10 or more 4 N / mm 2 It is more preferable that the area of ​​the membrane portion 2 is 1000 cm or less. 2 When the bending stiffness K is 1N / mm 2 By satisfying the above, the vibration of the film part 2 is improved, and it is possible to suppress deterioration of the sound insulation performance in the frequency band to be insulated. 2 When the bending stiffness K is 10 5 N / mm 2 When the thickness is as follows, the soundproof structure 1a becomes flexible and easy to install. The cross-sectional shape of the film portion 2 is not particularly limited, and may be flat or may have irregularities.

[0033] Materials for the film portion 2 include cross-linked (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. Examples of crosslinking (vulcanization) methods include a method of crosslinking (vulcanization) by heating using a crosslinking agent (vulcanizing agent) such as an organic peroxide, a phenolic resin, an oxime compound, sulfur, a sulfur-based compound, or a polyamine compound, or a method of crosslinking by irradiating with an electron beam. The crosslinked (vulcanized) rubber may contain various known compounding agents commonly used as rubber 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, mildew inhibitors, acid acceptors, silane coupling agents, antistatic agents, ultraviolet absorbers, etc.). These crosslinked (vulcanized) rubbers, crosslinking agents (vulcanizing agents), and compounding agents may be made from biomass materials.

[0034] Examples of thermoplastic elastomers include olefin-based thermoplastic elastomers, styrene-based thermoplastic elastomers, polyester-based thermoplastic elastomers, polyvinyl chloride-based thermoplastic elastomers, ethylene-vinyl acetate-based thermoplastic elastomers, and thermoplastic polyurethanes. Examples of plastics 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 film portion 2 is preferably ethylene-propylene-diene rubber, thermoplastic olefin-based elastomer, thermoplastic styrene-based elastomer, polyethylene, polypropylene, polyethylene terephthalate, thermoplastic polyurethane, or the like.

[0036] The support wall 3 is preferably made of a flexible material that is soft enough to support the membrane 2. The thickness of the support wall 3 is preferably 0.5 mm to 5.0 mm, and more preferably 1.0 mm to 3.0 mm. When the thickness of the support wall 3 is 0.5 mm or more, the shape retention of the soundproof structure 1a is improved. When the thickness of the support wall 3 is 5.0 mm or less, the vibration of the membrane 2 is improved, sound insulation in the frequency band to be insulated is improved, and an increase in the weight of the entire soundproof structure 1a can be suppressed. The height of the support wall 3 extending in a direction perpendicular to the membrane 2 is preferably 5 mm to 20 mm, and more preferably 10 mm to 20 mm. The height of the support wall 3 may vary partially. When the height of the support wall 3 varies partially, the higher part may be 10 mm to 20 mm, more preferably 12 mm to 20 mm, and even more preferably 14 mm to 20 mm. By ensuring that the height of the support wall portion 3 is not too low, the weight portion 4 can have a sufficient height as a spring-mass resonator. By ensuring that the height of the support wall portion 3 is not too high, the overall weight can be reduced. The material of the support wall portion 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. By ensuring that the durometer A hardness of the support wall portion 3 is 1 or more, the shape retention of the soundproof structure 1a can be maintained. By ensuring that the durometer A hardness of the support wall portion 3 is 90 or less, vibrations from the support wall portion 3 are prevented from being transmitted to the membrane portion 2, which would deteriorate the soundproofing performance. The soundproof structure 1a becomes flexible and easy to install. The stiffness k of the support wall portion 3 is expressed as k = E' × A / L, where E' is the dynamic storage modulus of elasticity, A is the cross-sectional area of ​​the support wall portion 3, and L is the height of the support wall portion 3. When the area of ​​the support wall portion 3 to be evaluated for stiffness is 1000 cm, the stiffness k is calculated as k = E' × A / L. 2 When the stiffness k is 10N / mm or more, 6 N / mm or less is preferable, and 10 2 N / mm or more 10 5 It is more preferable that the area of ​​the support wall 3 is 1000 cm or less. 2When the area of ​​the support wall portion 3 is 1000 cm, the stiffness k is 10 N / mm or more, so that the shape retention of the soundproof structure 1a can be maintained. 2 When the stiffness k is 10 6 By setting the resistance to N / mm or less, it is possible to prevent vibrations from the support wall portion 3 from being transmitted to the film portion 2, which would deteriorate the sound insulation performance, and the soundproof structure 1a does not become rigid, making it easy to install.

[0037] Examples of materials for the support wall portion 3 include cross-linked (vulcanized) rubber, thermoplastic elastomers, and resin foams. The cross-linked (vulcanized) rubber and thermoplastic elastomers may be the same as those listed as materials for the membrane portion 2. The resin foams may have either a closed-cell structure or an open-cell structure, and examples include polyurethane foam, polystyrene foam, polyethylene foam, and ethylene-vinyl acetate rubber (EVA) foam. Specifically, the materials for the support wall portion 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 from biomass materials.

[0038] The material of the spring portion 4a of the weight portion 4 is a flexible material such as cross-linked (vulcanized) rubber, thermoplastic elastomer, or resin foam. The cross-linked (vulcanized) rubber, thermoplastic elastomer, or resin foam may be the same as the materials listed as the materials of the support 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, or polyurethane foam. These materials may be made from biomass raw materials.

[0039] The material of the mass portion 4b is not particularly limited, but it may be 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. By making the weight of the mass portion 4b at least twice the mass of the spring portion 4a, the weight portion 4 can be made to resonate sufficiently in the frequency range to be sound-insulated, thereby achieving a good sound-insulating effect. When the material of the mass portion 4b is resin, the resin may be made from 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 that is the main target of sound insulation. For example, if the mass of the mass portion 4b is 1.0 g and the main target frequency of sound insulation is 1000 Hz or less, the spring constant of the spring portion 4a is 1 N / mm or more and 50 N / mm or less.

[0041] With this configuration, the film portion 2, the support wall portion 3, and the weight portion 4 are all relatively lightweight, and the dimensions in the direction perpendicular to the film portion 2 are relatively small. As described above, the soundproof structure 1a 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 bands of road noise and tire pattern noise in automobiles), as mentioned above. Furthermore, the support wall portion 3 made of a flexible material can be easily and stably installed on both flat panels 14 or automobile components and curved or uneven panels 14 or automobile components without being fixed by adhesive or the like.

[0042] The soundproofing structure 1a of this embodiment is located near the front end of the floor carpet 1, separating the passenger compartment 13 from a space 12 housing the front tires 11, a region of the vehicle where sound propagation is particularly strong. If the entire floor carpet 1 were made of the soundproofing structure 1a, the soundproofing effect would be high, but the weight of the floor carpet 1 would be large, potentially adversely affecting the vehicle's performance. In contrast, the soundproofing structure 1a with a high soundproofing effect is located in the floor carpet 1 of this embodiment, facing the front tires 11, which are in contact with the ground and where sound propagation is particularly strong. This effectively prevents sound from entering while minimizing weight gain. Furthermore, the soundproofing structure 1a can be easily and stably installed on panels 14 of various shapes or on automotive components (such as the dash insulator 10) placed on the panels 14, without the need for adhesive or other fastening. Therefore, the floor carpet 1 of this embodiment can be stably supported by being laminated on a complex-shaped panel 14 or an automotive component (such as a dash insulator 10) placed on the panel 14. Furthermore, since the soundproof structure 1a of this embodiment is integrated with the floor carpet 1, the number of components is not increased, and installation is simple. Methods for incorporating the soundproof structure 1a into the floor carpet 1 include ultrasonic welding, adhesion with a hot-melt adhesive, fastening with clips, bolts, rivets, and the like, and insert molding. As shown in the enlarged example in FIG. 7 , the film 2 and the floor carpet body may each be partially thinned, or the thinned portions may be overlapped and joined by any of the methods described above to integrate the film 2 and the floor carpet body, thereby incorporating the soundproof structure 1a into the floor carpet 1. The soundproof structure 1a, which constitutes part of the floor carpet 1, may be exposed within the vehicle interior 13, or may be covered with a sheet material (not shown) to prevent the soundproof structure 1a from being exposed within the vehicle interior.

[0043] The floor carpet 1 may have a similar structure to conventional carpets. Specifically, it may be made of porous materials such as felt or polyurethane foam, or resin foam, and may also contain sheets made of resin or rubber materials such as EPDM. These materials may also be made from biomass raw materials.

[0044] [Second embodiment] Fig. 8 shows a side view of an automobile equipped with a soundproofing structure 6 according to a second embodiment of the present invention, and Fig. 9 is an enlarged side view showing a main portion of the interior of the automobile. In this automobile, the soundproofing structure 6 according to the present invention is arranged so as to overlap a panel 14 provided at the boundary between a space 12 in which a front tire 11 is accommodated and a passenger compartment 13, or an automobile component (such as a dash insulator 10) placed on the panel 14. However, the soundproofing structure 6 according to this embodiment is formed as a separate component from a floor carpet 8. The floor carpet 8 is similar to a conventional floor carpet. The soundproofing structure 6 according to this embodiment is arranged between a portion of the floor carpet 8 on the front side of the vehicle that partially covers the space 12 in which the front tire 11 is accommodated, and the panel 14 or an automobile component (such as the dash insulator 10) placed on the panel 14. As in the first embodiment, as shown schematically in Figure 8, the soundproofing structure 6 is located in part of the area separating the space that houses the front tire 11 from the vehicle interior 13, generally at or further forward of the position where the feet of an occupant P sitting in a seat 15 are placed. The structure of the soundproofing structure 6 may be the same as that of the soundproofing structure 1a of the first embodiment shown in Figures 5 and 6, so a description thereof will be omitted. The film portion 2 of the soundproofing structure 6 and the floor carpet 8 overlap. The film portion 2 and the floor carpet 8 may be joined to each other, or may simply be placed one on top of the other without being joined to each other.

[0045] In both the first and second embodiments described above, the lightweight and thin soundproofing structures 1a, 6 provide high sound insulation in a specific frequency range (for example, frequencies below 1000 Hz, which are the main frequency bands of road noise and tire pattern noise in automobiles), and can be easily installed without the need for adhesive. In particular, they can efficiently block noise from the space 12 housing the front tires 11, which has a large sound propagation rate, from entering the passenger compartment 13, providing a significant soundproofing effect. Furthermore, in this embodiment, the existing floor carpet 8 can be used as is, thereby keeping costs low.

[0046] In both the first and second embodiments described above, the specific structure of the soundproofing structures 1a, 6 is not limited to the configuration shown in FIGS. 5 and 6. Other configuration examples of the soundproofing structures 1a, 6 will be described below. FIG. 10(A) is a perspective view showing another example of the soundproofing structures 1a, 6 of the present invention, and FIG. 10(B) is a cross-sectional view taken along line AA in FIG. 10(A) and inverted upside down. FIG. 11 is a schematic cross-sectional view of a floor carpet 1 similar to that of the first embodiment, including the soundproofing structure 1a shown in FIG. 10. In the following examples, the spring portion 4a and the mass portion 4b of the weight portion 4 of the soundproofing structures 1a, 6 have different shapes and dimensions. In the examples shown in FIGS. 10 and 11, the spring portion 4a is a small-diameter cylindrical portion, and the mass portion 4b is a large-diameter cylindrical portion. Alternatively, although not shown, the spring portion 4a may be elongated and cylindrical, and the mass portion 4b may be spherical, with the diameter of the cross-sectional shape of the cylindrical spring portion 4a being smaller than the diameter of the spherical mass portion 4b. In these examples, 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 may have a larger mass than the spring portion 4a, thereby forming a spring-mass resonator. However, in these examples, the spring portion 4a and the mass portion 4b may be made of different materials, with the mass portion 4b having a larger mass than the spring portion. Furthermore, although not shown, the spring portion 4a may be truncated conically, and the mass portion 4b may be cylindrically shaped, with the diameter of the smallest part of the truncated conical spring portion 4a substantially equal to the diameter of the cylindrical mass portion 4b. In this example, the spring portion 4a has a larger volume than the mass portion 4b. In this case, the mass portion 4b is formed of a material with a higher density than the spring portion 4a, and the mass portion 4b has a larger mass than the spring portion, thereby forming a spring-mass resonator. In this way, if the spring portion 4a has a truncated cone shape tapering away from the membrane portion 2, it is easy to release from a mold when the membrane portion 2 and the spring portion 4a are integrally molded. The shape and dimensions of the weight portion 4 of the present invention are not limited, and the shapes shown in Figures 5-6, 10-11, and various other shapes not shown can be used. 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 within the compartment 5.

[0047] In the soundproof structures 1a and 6 shown in Figures 5-6 and 10-11, the spring portion 4a and the mass portion 4b of the weight portion 4 are made of different materials and / or different volumes, thereby making the mass portion 4b larger than the spring portion 4a, thereby forming a spring-mass resonator and achieving a sufficient sound-proofing effect. In other words, the materials, shapes, and dimensions of the spring portion 4a and the mass portion 4b are determined so that a spring-mass resonator that can provide a sufficient sound-proofing effect can be formed. The materials, shapes, and dimensions of the spring portion 4a and the mass portion 4b can be freely selected as long as the mass of the mass portion 4b can be made larger than the spring portion 4a to the extent that a spring-mass resonator that can provide a sufficient sound-proofing effect can be formed. However, the spring portion 4a must be made of a flexible material in order to function as a spring.

[0048] [Modification of soundproof structure] FIG. 12(A) is a perspective view showing a modified example of the soundproof structure 1a, 6 used in the first and second embodiments of the present invention, and FIG. 12(B) is a cross-sectional view taken along line AA in FIG. 12(A) and inverted. The soundproof structure 1a, 6 has a single-structure weight portion 7 that is not divided into a spring portion and a mass portion. In this soundproof structure 1a, 6, the entire weight portion 7 functions as the mass portion, and a spring-mass resonator is configured in which the membrane portion 2 functions as the spring portion. As an example, the mass of the weight portion 7 is approximately 0.1 g to 2.0 g. The material of the weight portion 7 is not limited and may be formed from, for example, synthetic resin or metal. The rest of the configuration is similar to that of the first and second embodiments described above, so a description thereof will be omitted. In the soundproof structure 1a, 6 of this modified example, membrane vibration is controlled by the action of the spring-mass resonator formed by the weight portion 7 and the membrane portion 2. This significantly reduces membrane vibration in a specific frequency range (e.g., below 1000 Hz), thereby providing high sound insulation. In addition, together with the membrane portion 2, the air in the space surrounded by the membrane portion 2 and the support wall portion 3 may function as part of the spring (air spring) of the spring mass resonator.

[0049] In this modified example, the membrane part 2 and the supporting wall part 3 both preferably have a dynamic storage modulus of 0.01 MPa or more and 100 MPa or less at a frequency of 1 Hz to 1000 Hz at 23° C., and a loss tangent of 0.01 or more and 0.50 or less at a frequency of 1 Hz to 1000 Hz at 23° C. Furthermore, it is more preferable that the membrane part 2 and the supporting wall part 3 both have a dynamic storage modulus (E') of 0.05 MPa or more and 50 MPa or less at a frequency of 1 Hz to 1000 Hz at 23° C., and a loss tangent (tanδ) of 0.05 or more and 0.50 or less at a frequency of 1 Hz to 1000 Hz at 23° C.

[0050] The support wall 3 of this modified example is made of any one of a material that has rubber elasticity but not energy elasticity, a material that has energy elasticity but not rubber elasticity, and a material that has both rubber elasticity and energy elasticity. Similarly, the membrane 2 of this modified example is made of any one of a material that has rubber elasticity but not energy elasticity, a material that has energy elasticity but not rubber elasticity, and a material that has both rubber elasticity and energy elasticity.

[0051] Although not shown, as another modification of the soundproof structures 1a and 6 used in the first and second embodiments of the present invention, the weight portion 7 can be configured to have a truncated cone shape that tapers away from the film portion 2. This configuration allows for good releasability from a mold when the film portion 2 and the weight portion 7 are integrally molded. In this modification, the shape of the weight portion 7 can be determined arbitrarily and is not particularly limited.

[0052] In any of the soundproofing structures 1a, 6 described above, the film portion 2 and the support wall portion 3 can be formed by integral molding or two-color molding using the above-mentioned materials, such as injection molding, compression molding, press molding, extrusion molding, transfer molding, or cast molding. Furthermore, at least a portion of the weight portions 4, 7 can also be formed together with the film portion 2 and the support wall portion 3 by integral molding, two-color molding, or insert molding using the above-mentioned materials. However, the soundproofing structures 1a, 6 may also be assembled by forming the film portion 2, the support wall portion 3, and the weight portions 4, 7 separately and then joining them together by adhesive or heat fusion.

[0053] In the soundproof structures 1a and 6 described above, as shown in FIGS. 13(A) and 13(B), the support wall 3 includes a plurality of first walls 3a extending in a first direction D1 parallel to the membrane 2 and a plurality of second walls 3b extending in a second direction D2 perpendicular to the first direction D1, and each compartment 5 has a square planar shape. In other words, the support wall 3 is a rectangular tube having a square cross-section that defines each compartment 5, and a large number of rectangular support walls 3 are arranged side by side, with the support walls 3 of adjacent compartments 5 being integrated. However, this configuration is not limited to this. For example, although not shown, the planar shape of each compartment 5 may be triangular, and the support wall 3 may be a rectangular tube having a triangular cross-section that defines each compartment 5. Alternatively, although not shown, the planar shape of each compartment 5 may be pentagonal, and the support wall 3 may be a rectangular tube having a pentagonal cross-section that defines each compartment 5. As shown in Figures 14(A) and 14(B), the planar shape of each compartment 5 may be hexagonal, and the support wall 3 may be a rectangular tube with a hexagonal cross-section that defines each compartment 5, forming a so-called honeycomb structure. Furthermore, although not shown, the planar shape of each compartment 5 may be circular, and the support wall 3 may be a cylinder with a circular cross-section that defines each compartment 5. When the planar shape of each compartment 5 is pentagonal or circular, gaps will form between the compartments 5. Therefore, it is preferable to determine the shape and dimensions of the support wall 3 so as to minimize these gaps, and it is preferable that the membrane 2 expand to fill these gaps. When the planar shape of each compartment 5 is triangular, quadrangular, or hexagonal, no gaps will form between the compartments 5. Furthermore, each compartment 5 may have various shapes (not shown), such as a rectangle, parallelogram, trapezoid, polygon with seven or more sides, ellipse, oval, etc., or may be irregular. The support wall portion 3 is formed to have a shape and dimensions that match the planar shape of each compartment 5.

[0054] The soundproofing structures 1a, 6 of the present invention are thin and lightweight, and are used by being placed on a curved or uneven automobile panel 14 or an automobile component (e.g., a dash insulator 10 shown in FIGS. 1 to 2 and 8) that is placed on the panel 14. The automobile panel 14 is basically an impermeable plate, and examples thereof include a metal plate (iron plate, steel plate, or aluminum plate) and a resin plate. When the panel 14 on which the soundproofing structures 1a, 6 are 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. The automobile component that is placed on the panel 14 is not particularly limited, but an example thereof is a component such as a dash insulator 10. The dash insulator 10 is a component made of a porous material (felt or polyurethane foam) or a rubber material. It is preferable that the end face of the support wall portion 3 of the soundproofing structures 1a, 6 opposite to the side attached to the membrane portion 2 is placed on the automobile panel 14 or an automobile component (such as the dash insulator 10) that is placed on the panel 14. In this case, the support wall portion 3 of the soundproofing structures 1a, 6 and the panel 14 or the automobile component 10 that is placed on the panel 14 may or may not be bonded, but it is preferable that the support wall portion 3 is not bonded to the panel 14 or the automobile component (such as the dash insulator 10) and is placed on the panel 14 or the automobile component (such as the dash insulator 10) when used. [Example]

[0055] Specific examples and comparative examples of the soundproof structures 1a and 6 of the present invention will be described below. [Example 1] The soundproof structures 1a and 6 of Example 1 of the present invention have the same structure as the soundproof structure 1a shown in Figures 5 and 6. The film portion 2 is made of an elastic body having a dynamic storage modulus of 0.01 MPa or more and 100 MPa or less at 23°C and at frequencies of 1 Hz to 1000 Hz, and a loss tangent of 0.01 or more and 0.50 or less at 23°C and at frequencies of 1 Hz to 1000 Hz. More specifically, the film part 2 of this example has a dynamic storage modulus (E') of 20.4 MPa and a loss tangent (tanδ) of 0.12 at 23°C and a frequency of 1 Hz, a dynamic storage modulus (E') of 23.0 MPa and a loss tangent (tanδ) of 0.13 at 23°C and a frequency of 10 Hz, a dynamic storage modulus (E') of 25.4 MPa and a loss tangent (tanδ) of 0.16 at 23°C and a frequency of 100 Hz, and a dynamic storage modulus (E') of 28.8 MPa and a loss tangent (tanδ) of 0.14 at 23°C and a frequency of 1000 Hz, a durometer A hardness of 70 according to JIS K6253, and a film thickness of 0.5 mm. The planar shape of this film part 2 has an area of ​​1000 cm. 2 If the square is , the bending stiffness K is 67.2N / mm 2 The planar shape has an area of ​​400 cm 2 If the square is , the bending stiffness K is 42.5N / mm 2 If the same material as the film portion 2 is used, the film thickness is 3 mm, and the plane shape has an area of ​​1000 cm 2 When a square membrane portion 2 is formed, its bending stiffness K is about 1.5×10 4 N / mm 2 is.

[0056] The support wall portion 3 of this embodiment is made of an elastic body having 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, and 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. More specifically, the support wall 3 of this example has a dynamic storage modulus (E') of 13.2 MPa and a loss tangent (tanδ) of 0.12 at 23°C and a frequency of 1 Hz, a dynamic storage modulus (E') of 15.0 MPa and a loss tangent (tanδ) of 0.14 at 23°C and a frequency of 10 Hz, a dynamic storage modulus (E') of 17.4 MPa and a loss tangent (tanδ) of 0.17 at 23°C and a frequency of 100 Hz, and a dynamic storage modulus (E') of 20.2 MPa and a loss tangent (tanδ) of 0.16 at 23°C and a frequency of 1000 Hz, a durometer A hardness according to JIS K6253 of 65, a plate thickness of 1.6 mm, and a height of 10 mm in the direction perpendicular to the membrane 2. However, only the outermost support wall 3 has a plate thickness of half that, 0.8 mm. The compartments 5 defined by the multiple support walls 3 (first wall 3a and second wall 3b) are square, measuring 25 mm x 25 mm, and there are 49 compartments 5 in the 200 mm x 200 mm square area (evaluation surface) of the membrane 2. However, only a portion of this area is shown schematically in the drawing. The weight 4 is cylindrical, with a diameter of 6 mm and a height (dimension in the direction perpendicular to the membrane 2) of 6 mm.

[0057] Of this weight portion 4, the spring portion 4a, which is the portion attached to the membrane portion 2, is 3 mm high and is made of an elastic body having a dynamic storage modulus of 0.01 MPa or more and 100 MPa or less at 23°C and at frequencies of 1 Hz to 1000 Hz, and a loss tangent of 0.01 or more and 0.50 or less at 23°C and at frequencies of 1 Hz to 1000 Hz. More specifically, spring portion 4a in this embodiment has a dynamic storage modulus (E') of 0.60 MPa and a loss tangent (tanδ) of 0.17 at 23°C and a frequency of 1 Hz, a dynamic storage modulus (E') of 0.74 MPa and a loss tangent (tanδ) of 0.24 at 23°C and a frequency of 10 Hz, a dynamic storage modulus (E') of 0.97 MPa and a loss tangent (tanδ) of 0.17 at 23°C and a frequency of 100 Hz, and a dynamic storage modulus (E') of 1.31 MPa and a loss tangent (tanδ) of 0.16 at 23°C and a frequency of 1000 Hz, and is made of silicone rubber with a durometer A hardness of 10 according to JIS K6253. Mass portion 4b, which is the portion of weight portion 4 opposite the side attached to membrane portion 2, also has a height of 3 mm and is made of rigid stainless steel (SUS304). The mass of the weight 4 is approximately 0.8 g, and the soundproof structure 1a has a resonance frequency peak at 600 Hz to 650 Hz in the direction perpendicular to the installation surface of the weight 4. The height of the entire soundproof structure 1a is 10.5 mm, and the surface density of the entire structure including the membrane 2, the support wall 3, and the weight 4 in one section 5 is 2.97 kg / m 2 The surface density is a value calculated from the weight and area of ​​the sample.

[0058] The sound insulation of the soundproofing structures 1a and 6 of this embodiment was measured with the end face of the support wall 3 opposite to the side attached to the membrane 2 facing the incident sound side. Specifically, in accordance with the intensity method specified in JIS A1441-1, a test facility with a reverberation chamber as the sound source room and a semi-anechoic chamber as the sound receiving room was used to determine the sound transmission loss (transmission loss) [dB] versus the 1 / 3 octave band center frequency [Hz] by 1 / 3 octave band analysis. The relationship between the 1 / 3 octave band center frequency and the sound transmission loss was determined and is shown in Figures 15(A) to 15(C), 16(A) to 16(C), and 18(B). The larger the sound transmission loss, the higher the sound insulation. Note that in the 1 / 3 octave band center frequencies [Hz] shown in Figures 15(A) to 18(B), 1 kHz corresponds to 1000 Hz, and the prefix "k" means 1000.

[0059] [Example 2] The soundproof structures 1a and 6 of Example 2 of the present invention have the same structure as the soundproof structures 1a and 6 shown in Fig. 12. The film portion 2 and the support wall portion 3 of this example are the same as the film portion 2 and the support wall portion 3 of Example 1. The weight portion 7 is made of EPDM having a durometer A hardness of 65 according to JIS K6253-3, and is cylindrical with a diameter of 13 mm and a height (dimension in the direction perpendicular to the film portion 2) of 5 mm. The mass of the weight portion 7 is approximately 0.85 g, and the surface density of this configuration is 3.04 kg / m 2 The sound insulation properties of the soundproof structures 1a and 6 of this example were determined in the same manner as in Example 1, and are shown in FIG.

[0060] [Example 3] The soundproof structure 1a, 6 of Example 3 of the present invention shown in Figure 19 has the same structure as Example 2, but has a weight 7 that is smaller than the weight 7 of Example 2. Figure 19(A) is a perspective view of the soundproof structure 1a, 6, and Figure 19(B) is a cross-sectional view taken along line AA and turned upside down. The film portion 2 and supporting wall portion 3 of this example are the same as the film portion 2 and supporting wall portion 3 of Example 1. The weight portion 7 is made of EPDM with a durometer A hardness of 65 according to JIS K6253-3, and is cylindrical with a diameter of 6 mm and a height (dimension in the direction perpendicular to the film portion 2) of 5 mm. The mass of the weight portion 7 is approximately 0.15 g. The surface density of this configuration is 2.54 kg / m 2 The sound insulation properties of the soundproof structures 1a and 6 of this example were determined in the same manner as in Example 1, and are shown in FIG.

[0061] [Example 4] A soundproof structure 1a, 6 (not shown) of Example 4 of the present invention has the same structure as Example 1, but has a support wall portion 3 that is softer than the support wall portion 3 of Example 1. The film portion 2 and weight portion 4 of this Example are the same as the film portion 2 and weight portion 4 of Example 1. The support wall portion 3 of this Example is made of an elastic body having a dynamic storage modulus of 0.01 MPa or more and 100 MPa or less at 23°C and at frequencies of 1 Hz to 1000 Hz, and a loss tangent of 0.01 or more and 0.50 or less at 23°C and at frequencies of 1 Hz to 1000 Hz. More specifically, the support wall portion 3 of this example has a dynamic storage modulus (E') of 1.48 MPa and a loss tangent (tanδ) of 0.07 at 23°C and a frequency of 1 Hz, a dynamic storage modulus (E') of 1.72 MPa and a loss tangent (tanδ) of 0.12 at 23°C and a frequency of 10 Hz, a dynamic storage modulus (E') of 2.00 MPa and a loss tangent (tanδ) of 0.11 at 23°C and a frequency of 100 Hz, and a dynamic storage modulus (E') of 2.33 MPa and a loss tangent (tanδ) of 0.12 at 23°C and a frequency of 1000 Hz, a durometer A hardness according to JIS K6253-3 of 30, a plate thickness of 1.6 mm, and a height of 10 mm in the direction perpendicular to the membrane portion 2. However, only the outermost support wall portion 3 has a plate thickness of half that, 0.8 mm. The areal density of this configuration is 2.52 kg / m 2The sound insulation properties of the soundproof structures 1a and 6 of this example were determined in the same manner as in Example 1, and are shown in FIG.

[0062] [Example 5] The soundproof structure 1a, 6 (not shown) of Example 5 has the same structure as Example 1, but has a film portion 2 that is softer than the film portion 2 of Example 1. The support wall portion 3 and weight portion 4 of this example are the same as the support wall portion 3 and weight portion 4 of Example 1. The film portion 2 of this example is made of EPDM having a durometer A hardness of 30 according to IS K6253-3, the same material as the support wall portion 3 of Example 4, and its shape and dimensions are the same as the film portion 2 of Example 1. The surface density of this configuration is 2.83 kg / m 2 The sound insulation properties of the soundproof structures 1a and 6 of this example were determined in the same manner as in Example 1, and are shown in FIG.

[0063] [Example 6] The soundproof structures 1a and 6 of Example 6 shown in Figure 20 have the same structure as Example 1, but have compartments 5 that are wider than the compartments 5 of Example 1. Figure 20(A) is a perspective view of the soundproof structures 1a and 6, and Figure 20(B) is a cross-sectional view taken along line AA and turned upside down. The film portion 2 and weight portion 4 of this example are the same as the film portion 2 and weight portion 4 of Example 1. The support wall portions 3 of this example are the same as the support wall portions 3 of Example 1, but are arranged side by side at wider intervals than in Example 1. As a result, each compartment 5 of this example is a square of 50 mm x 50 mm, and its area is 2500 mm. 2 The areal density of this configuration is 1.60 kg / m 2 There are nine sections 5 in a 200 mm × 200 mm square area (evaluation surface) of the film part 2. However, only a part of this area is shown in the drawing. The sound insulation of the soundproof structure 1a, 6 of this example was determined in the same manner as in Example 1, and is shown in Figure 16(B).

[0064] [Example 7] The soundproof structure 1a, 6 (not shown) of Example 7 has the same structure as Example 1, but the weight portion 4 is cylindrical with a diameter of 13 mm and a height (dimension in the direction perpendicular to the film portion 2) of 9 mm. Of this weight portion 4, the spring portion 4a, which is the portion attached to the film portion 2, has a height of 4 mm and is made of an elastic body having a dynamic storage modulus of 0.01 MPa or more and 100 MPa or less at 23°C and at frequencies of 1 Hz to 1000 Hz, and a loss tangent of 0.01 or more and 0.50 or less at 23°C and at frequencies of 1 Hz to 1000 Hz. More specifically, the spring portion 4a in this embodiment is made of polyurethane foam having a dynamic storage modulus of 0.06 MPa and a loss tangent (tanδ) of 0.15 at 23°C and 1 Hz, a dynamic storage modulus (E') of 0.07 MPa and a loss tangent (tanδ) of 0.15 at 23°C and 10 Hz, a dynamic storage modulus (E') of 0.08 MPa and a loss tangent (tanδ) of 0.15 at 23°C and 100 Hz, and a dynamic storage modulus (E') of 0.10 MPa and a loss tangent (tanδ) of 0.15 at 23°C and 1000 Hz. The mass portion 4b, which is the portion of the weight portion 4 opposite the side attached to the membrane portion 2, is 5 mm high and made of EPDM having a durometer A hardness of 65 according to JIS K6253-3. The mass of the weight portion 4 is approximately 1.0 g.

[0065] The membrane part 2 and the support wall part 3 of this embodiment are the same as the membrane part 2 and the support wall part 3 of Example 1. The surface density of this structure is 3.08 kg / m 2 The sound insulation properties of the soundproof structures 1a and 6 of this example were determined in the same manner as in Example 1, and are shown in FIG.

[0066] [Example 8] The soundproof structures 1a and 6 (not shown) of Example 8 have the same structure as the soundproof structures 1a and 6 shown in Figures 10 and 11. The film portion 2 and support wall portion 3 of this example are the same as those of Example 1, but the weight portion 4 of this example consists of a small-diameter, cylindrical spring portion 4a and a large-diameter, cylindrical mass portion 4b. The spring portion 4a, which is the portion of the weight portion 4 attached to the film portion 2, is cylindrical with a diameter of 6 mm and a height (dimension perpendicular to the film portion 2) of 3 mm and is made of the same material as the spring portion 4a of the weight portion 4 of Example 1 (silicone rubber with a durometer A hardness of 10 according to JIS K6253-3). The mass portion 4b, which is the portion of the weight portion 4 opposite the side attached to the film portion 2, is cylindrical with a diameter of 13 mm and a height of 5 mm and is made of EPDM with a durometer A hardness of 65 according to JIS K6253-3. The mass of the weight 4 is approximately 1.0 g. The surface density of this structure is 3.13 kg / m 2 The sound insulation properties of the soundproof structures 1a and 6 of this example were determined in the same manner as in Example 1, and are shown in Figures 16(C) and 17(A).

[0067] [Example 9] The soundproof structures 1a and 6 (not shown) of Example 9 have the same structure as the soundproof structures 1a and 6 shown in Figures 10 and 11. The film portion 2 and weight portion 4 of this example are the same as the film portion 2 and weight portion 4 of Example 8, but the support wall portion 3 of this example is made of EPDM with a durometer A hardness of 30 according to JIS K6253, a plate thickness of 1.6 mm, and a height of 10 mm in the direction perpendicular to the film portion 2. The surface density of this structure is 2.81 kg / m 2 The sound insulation properties of the soundproof structures 1a and 6 of this example were determined in the same manner as in Example 1, and are shown in Figures 17(A) to 17(C).

[0068] [Example 10] The soundproof structure 1a, 6 of Example 10 shown in Fig. 21 has the same structure as the soundproof structure 1a, 6 shown in Figs. 10-11. Fig. 21 is a cross-sectional view of the soundproof structure 1a, 6. The film portion 2 and weight portion 4 of this example are the same as the film portion 2 and weight portion 4 of Example 9, but the support wall portion 3 of this example is made of EPDM with a durometer A hardness of 30 according to JIS K6253, a plate thickness of 1.6 mm, and a height of 14 mm in the direction perpendicular to the film portion 2. The surface density of this configuration is 3.16 kg / m 2 The sound insulation properties of the soundproof structures 1a and 6 of this example were determined in the same manner as in Example 1, and are shown in FIG.

[0069] [Example 11] The soundproof structure 1a, 6 of Example 11 shown in Figure 22 has the same structure as the soundproof structure 1a, 6 shown in Figures 10 to 11. Figure 22(A) is a perspective view of the soundproof structure 1a, 6, and Figure 22(B) is a cross-sectional view taken along line BB and inverted upside down. The film portion 2 and weight portion 4 of this example are the same as the film portion 2 and weight portion 4 of Example 9, but in this example, some support wall portions 3d of the multiple support wall portions are taller in the direction perpendicular to the film portion 2 than other support wall portions 3c. That is, the soundproof structure 1a, 6 of this example has support wall portions (some support wall portions) 3d that are tall like the support wall portions 3 of Example 10, and support wall portions (other support wall portions) 3c that are short like the support wall portions 3 of Example 9. Specifically, the support wall portion 3c is made of EPDM having a durometer A hardness of 30 according to JIS K6253, a plate thickness of 1.6 mm, and a height of 10 mm in a direction perpendicular to the membrane portion 2, while the support wall portion 3d is made of EPDM having a durometer A hardness of 30 according to JIS K6253, a plate thickness of 1.6 mm, and a height of 15 mm in a direction perpendicular to the membrane portion 2. The support wall portion 3d has a height 1.5 times that of the support wall portion 3c. In this embodiment, as shown in Figures 22(A) and 22(B), rows in which high-height support wall portions 3d are arranged alternate with rows in which only low-height support wall portions 3c are arranged. As a result, of the 49 square compartments 5 arranged in a 7x7 grid, 16 compartments 5 are surrounded by high-height support wall portions 3d. The surface density of this configuration is 3.02 kg / m 2The sound insulation properties of the soundproof structures 1a and 6 of this example were determined in the same manner as in Example 1, and are shown in FIG.

[0070] [Example 12] The soundproof structure 1a, 6 (not shown) of Example 12 has the same structure as the soundproof structure 1a, 6 shown in Figures 10 and 11. The weight portion 4 of this example is the same as the weight portion 4 of Example 8. The membrane portion 2 and supporting wall portion 3 of this embodiment are formed by integral molding of a styrene-based thermoplastic elastomer (TPS) with a dynamic storage modulus (E') of 7.81 MPa and a loss tangent (tanδ) of 0.06 at 23°C and a frequency of 1 Hz, a dynamic storage modulus (E') of 8.62 MPa and a loss tangent (tanδ) of 0.08 at 23°C and a frequency of 10 Hz, a dynamic storage modulus (E') of 9.19 MPa and a loss tangent (tanδ) of 0.11 at 23°C and a frequency of 100 Hz, and a dynamic storage modulus (E') of 10.3 MPa and a loss tangent (tanδ) of 0.08 at 23°C and a frequency of 1000 Hz, a durometer A hardness of 50 according to JIS K6253, a membrane portion 2 thickness of 1.0 mm, a supporting wall portion 3 thickness of 1.2 mm, and a height perpendicular to the membrane portion 2 of 10 mm. The areal density of this configuration is 2.56 kg / m 2 The sound insulation properties of the soundproof structures 1a and 6 of this example were determined in the same manner as in Example 1, and are shown in FIG.

[0071] [Example 13] The soundproofing structures 1a and 6 (not shown) of Example 13 have the same structure as the soundproofing structures 1a and 6 shown in Figures 10 and 11. The film portion 2 and the support wall portion 3 of this example are the same as the film portion 2 and the support wall portion 3 of Example 12. The weight portion 4 of this example is made up of a small-diameter cylindrical spring portion 4a and a large-diameter cylindrical mass portion 4b. The spring portion 4a, which is the part of the weight portion 4 that is attached to the membrane portion 2, is cylindrical with a diameter of 6 mm and a height (dimension perpendicular to the membrane portion 2) of 3 mm, and is made of TPS with a dynamic storage modulus (E') of 0.19 MPa and a loss tangent (tanδ) of 0.03 at 23°C and a frequency of 1 Hz, a dynamic storage modulus (E') of 0.19 MPa and a loss tangent (tanδ) of 0.04 at 23°C and a frequency of 10 Hz, a dynamic storage modulus (E') of 0.19 MPa and a loss tangent (tanδ) of 0.25 at 23°C and a frequency of 100 Hz, and a dynamic storage modulus (E') of 0.23 MPa and a loss tangent (tanδ) of 0.04 at 23°C and a frequency of 1000 Hz, and a durometer A hardness of 5 according to JIS K6253. The mass portion 4b, which is the portion of the weight portion 4 opposite to the side attached to the membrane portion 2, is cylindrical with a diameter of 11 mm and a height of 6 mm, and is made of EPDM having a durometer A hardness of 70 according to JIS K6253-3. The surface density of this structure is 2.50 kg / m 2 The sound insulation properties of the soundproof structures 1a and 6 of this example were determined in the same manner as in Example 1, and are shown in FIG.

[0072] [Example 14] The soundproof structures 1a and 6 (not shown) of Example 14 have the same structure as the soundproof structures 1a and 6 shown in Figures 10 and 11. The film portion 2 and support wall portion 3 of this example are the same as the film portion 2 and support wall portion 3 of Example 12. The weight portion 4 of this example is composed of a small-diameter cylindrical spring portion 4a and a large-diameter cylindrical mass portion 4b. The spring portion 4a, which is the portion of the weight portion 4 attached to the film portion 2, is cylindrical with a diameter of 6 mm and a height (dimension in the direction perpendicular to the film portion 2) of 3 mm. The mass portion 4b, which is the portion of the weight portion 4 opposite to the side attached to the film portion 2, is cylindrical with a diameter of 9 mm and a height of 6 mm. The spring portion 4a and mass portion 4b of the weight portion 4 in this embodiment are made of TPS having a dynamic storage modulus (E') of 0.21 MPa and a loss tangent (tanδ) of 0.04 at 23°C and a frequency of 1 Hz, a dynamic storage modulus (E') of 0.23 MPa and a loss tangent (tanδ) of 0.03 at 23°C and a frequency of 10 Hz, a dynamic storage modulus (E') of 0.29 MPa and a loss tangent (tanδ) of 0.05 at 23°C and a frequency of 100 Hz, and a dynamic storage modulus (E') of 0.25 MPa and a loss tangent (tanδ) of 0.17 at 23°C and a frequency of 1000 Hz, and a durometer A hardness of 5 according to JIS K6253. The areal density of this configuration is 2.14 kg / m 2 The sound insulation properties of the soundproof structures 1a and 6 of this example were determined in the same manner as in Example 1, and are shown in FIG.

[0073] [Comparative Example 1] As Comparative Example 1, when a member having the same mass as the soundproof structure 1a and 6 of Example 1 is placed, the theoretical sound insulation value calculated based on the mass law is obtained, and the relationship between the 1 / 3 octave band center frequency and the sound transmission loss is shown in Figure 15(A). The surface density of this structure is 2.90 kg / m 2 is.

[0074] Comparative Example 2 As Comparative Example 2, the sound insulation of only the film portion 2 was measured in the same manner as in Example 1, and the relationship between the 1 / 3 octave band center frequency and the sound transmission loss is shown in Figure 15(A). The film portion 2 of this Comparative Example is the same as the film portion 2 of Example 1, and does not have the support wall portion 3 and weight portion 4 as in Example 1. The surface density of this configuration is 0.68 kg / m 2 is.

[0075] Comparative Example 3 As Comparative Example 3, a soundproof structure consisting only of a film portion 2 and a supporting wall portion 3 was fabricated as shown in Figure 23. Figure 23(A) is a perspective view of this soundproof structure, and Figure 23(B) is a cross-sectional view taken along line AA and turned upside down. The sound insulation of the soundproof structure was measured using the same method as in Example 1, and the relationship between the 1 / 3 octave band center frequency and the sound transmission loss is shown in Figures 15(A) to 15(B) and 16(C). The film portion 2 and supporting wall portion 3 of this comparative example are the same as those of Example 1, but there is no weight portion 4. The surface density of this structure is 2.43 kg / m 2 is.

[0076] Comparative Example 4 The soundproof structure of Comparative Example 4 (not shown) has substantially the same structure as that of Example 1, but has a support wall portion 3 that is harder and less flexible than the support wall portion 3 of Example 1. The film portion 2 and weight portion 4 of this comparative example are the same as the film portion 2 and weight portion 4 of Example 1. The support wall 3 of this comparative example is made of polylactic acid (PLA resin) having a dynamic storage modulus (E') of 2.03 GPa and a loss tangent (tan δ) of 0.0045 at 23°C and a frequency of 1 Hz, a dynamic storage modulus (E') of 2.04 GPa and a loss tangent (tan δ) of 0.000060 at 23°C and a frequency of 10 Hz, a dynamic storage modulus (E') of 2.05 GPa and a loss tangent (tan δ) of 0.045 at 23°C and a frequency of 100 Hz, and a dynamic storage modulus (E') of 2.07 GPa and a loss tangent (tan δ) of 0.0079 at 23°C and a frequency of 1000 Hz, and its shape and dimensions are the same as those of the support wall 3 of Example 1. The areal density of this configuration is 2.63 kg / m 2The sound insulation of the soundproof structure of this comparative example was determined in the same manner as in Example 1, and the results are shown in FIG.

[0077] Comparative Example 5 As Comparative Example 5, a soundproof structure consisting only of a film portion 2 and a supporting wall portion 3 was fabricated in the same manner as in Comparative Example 3, and its sound insulation was measured in the same manner as in Example 1. Figure 18(A) shows the relationship between the 1 / 3 octave band center frequency and the sound transmission loss. The film portion 2 and supporting wall portion 3 of this comparative example are different from the film portion 2 and supporting wall portion 3 of Example 1 and Comparative Example 3, but are the same as the film portion 2 and supporting wall portion 3 of Example 12. Furthermore, the soundproof structure of this comparative example does not have a weight portion 4. The surface density of this configuration is 1.88 kg / m 2 is.

[0078] Comparative Example 6 The soundproof structure of Comparative Example 6 (not shown) has the same structure as Example 1, but has a film portion 2 made of a resin material with a thinner film thickness than the film portion 2 of Example 1. The supporting wall portion 3 and weight portion 4 of this comparative example are the same as the supporting wall portion 3 and weight portion 4 of Example 1. The film portion 2 of this comparative example is made of low-density polyethylene (LDPE) with a film thickness of 0.05 mm. The surface density of this structure is 2.25 kg / m 2 The sound insulation of the soundproof structure of this comparative example was determined in the same manner as in Example 1, and the results are shown in FIG.

[0079] [result] The results of comparing the above-mentioned Examples 1 to 14 of the present invention with Comparative Examples 1 to 6 will be explained. Referring to Fig. 15(A), it can be seen that the soundproofing structures 1a and 6 of the present invention improve the soundproofing effect. In particular, the soundproofing structures 1a and 6 of Example 1 provide a soundproofing effect significantly greater than the theoretical value based on the mass law (Comparative Example 1) in the frequency band higher than 630 Hz, demonstrating the great effect of the present invention. Furthermore, it can be seen that Example 1, which has a film portion 2, a support wall portion 3, and a weight portion 4, has greater soundproofing properties than Comparative Examples 2 and 3, particularly in the frequency band lower than 1.25 kHz.

[0080] Referring to FIG. 15(B), it can be seen that the soundproofing structures 1a and 6 of Example 1 and the soundproofing structures 1a and 6 of Examples 2 and 3, which are modifications thereof, provide similarly favorable sound insulation effects. When the weight 4 itself constitutes a spring-mass resonator, as in Example 1, particularly favorable sound insulation is achieved near frequencies (e.g., 630 Hz to 1000 Hz) where the vibration of the membrane 2 is reduced by the resonance of the spring-mass resonator. On the other hand, when the spring-mass resonator is formed by the weight 7 and the membrane 2, as in Examples 2 and 3, the frequency band where sound insulation is particularly favorable can be adjusted by adjusting the weight of the weight 7. For example, if the weight 7 has a mass similar to that of the weight 4 of Example 1, the frequency band where sound insulation is particularly favorable is around 1000 Hz. By reducing the weight of the weight 7, the frequency band where sound insulation is particularly favorable can be shifted to a higher frequency.

[0081] 15(C), it can be seen that if the support wall 3 of the soundproof structure is not made of a flexible material, the sound insulation is poor, but if the support wall 3 is made of a flexible material, good sound insulation can be obtained. This is thought to be because if the support wall 3 is made of a hard material rather than a flexible material, vibrations are easily transmitted to the membrane 2 via the support wall 3, whereas if the support wall 3 is made of a flexible material, vibrations are less likely to be transmitted to the membrane 2 via the support wall 3. Note that the frequency band in which sound insulation is particularly good can be adjusted by changing the hardness of the support wall 3. For example, if the support wall 3 is made softer, the frequency band in which sound insulation is particularly good can be shifted to a lower frequency side.

[0082] 16(A), it can be seen that if the film portion 2 of the soundproof structure is too soft, the sound insulation performance will be slightly reduced. This is thought to be because if the film portion 2 is too soft, vibrations of a degree sufficient for the spring mass resonator to function properly will not be transmitted to the spring mass resonator.

[0083] Referring to Figure 16(B), it can be seen that if each section 5 of the membrane section 2 defined by the support wall section 3 of the soundproof structure is too large, the sound insulation performance will be slightly reduced. This is thought to be because if each section 5 is too large, the spring mass resonator will not function sufficiently, and the vibration reduction effect will be reduced. Therefore, each section 5 should be made small to some extent (for example, 1000 mm 2 ) is preferred.

[0084] 16(C) shows that even if the material and shape of the weight 4 of the soundproof structure are different, as long as the material and shape are within the preferred ranges, the soundproofing function of the present invention will be exhibited. Therefore, it is clear that the material and shape of the weight 4, etc. can be freely set within the preferred ranges.

[0085] 17(A) shows that a similar sound-insulating effect can be obtained even if the durometer A hardness according to JIS K6253-3 of the support wall portion 3 differs to some extent. And, referring to FIG. 17(B) shows that a similar sound-insulating effect can be obtained even if the height of the support wall portion 3 extending in the direction perpendicular to the film portion 2 differs to some extent.

[0086] 18(C), it can be seen that a good soundproofing effect can be obtained even when only some of the support walls 3d among the multiple support walls are increased in height in the direction perpendicular to the film 2, while the heights of the other support walls 3c are decreased. When the sound source or the soundproofing structure 1a, 6 is supported by an external member (not shown), if there are too few high support walls 3d, it becomes difficult to stably support the soundproofing structure 1a, 6. If there are too many high support walls 3d, the weight of the entire soundproofing structure 1a, 6 increases. Therefore, it is preferable that the compartments 5 surrounded by the high support walls 3d account for 5% or more of the total compartments 5 of the soundproofing structure 1a, 6. Furthermore, when viewing a cross section of each support wall 3c, 3d parallel to the film 2, it is preferable that the total cross-sectional area of ​​the high support walls 3d be 10% or more of the total cross-sectional area of ​​all the support walls 3c, 3d of the soundproofing structure 1a, 6. In Example 11, the planar shape of the film part 2 was a square of 25 mm × 25 mm, and the 20 mm × 20 mm (area: 400 cm) 2) there are 7 x 7 = 49 compartments 5, of which 16 compartments 5 are compartments 5 surrounded by high support wall portions 3d, which is a preferable proportion of 32.6%.

[0087] In addition, even if the height of all support wall portions 3 is high as in Example 10, or even if the height of only some support wall portions 3d is high as in Example 11, it is preferable to keep the overall height of soundproof structures 1a, 6 to 20 mm or less, as mentioned above, in order to prevent an increase in the overall weight of soundproof structures 1a, 6 and to prevent installation restrictions.

[0088] Referring to FIG. 18(A), it can be seen that even if the membrane portion 2 and the support wall portion 3 are formed by integral molding of a thermoplastic material, the provision of the weight portion 4 provides good sound insulation. In a spring-mass resonator consisting of the spring portion 4a and the mass portion 4b of the weight portion 4, as in Example 13, it can be seen that if the spring portion 4a is softer, the resonant frequency shifts to the lower frequency side, and a greater sound insulation effect can be obtained at the lower frequency side. In this way, by changing the configuration of the weight portion 4, it is possible to adjust the sound insulation frequency band. Furthermore, it can be seen that good sound insulation can be obtained even if the weight portion 4 is made of a single material, as in Example 14. Therefore, productivity can be improved by manufacturing the weight portion 4 from a single material.

[0089] In the present invention, by incorporating the soundproofing structures 1a, 6 as exemplified in Examples 1 to 14 described above into the floor carpet 1 (see FIGS. 1 to 4 and 7) or by overlapping them with the floor carpet 8 (see FIGS. 8 and 9), it is possible to effectively reduce the intrusion of noise from the front tires 11 that contact the ground into the vehicle interior 13. In particular, in electric vehicles, although not shown, a heavy motor located in the floor of the vehicle interior may be effective in reducing vibrations in the floor, but it is not very effective in reducing noise from areas other than the floor, particularly noise from the tires that contact the ground. Therefore, reducing the intrusion of noise from the front tires into the vehicle interior using the present invention is extremely effective in quieting the vehicle interior of an electric vehicle.

[0090] The present invention may have the following configuration. [1] The vehicle is arranged at least in part at a position separating the space in which the front tires are accommodated from the passenger compartment, The device has an elastic membrane portion, an elastic support wall portion erected on the membrane portion, and a weight portion erected on the membrane portion, the membrane portion is divided into a plurality of compartments by the support wall portion, and the weight portion is located inside each of the plurality of compartments or inside some of the plurality of compartments, In the compartments in which the weight portions are located, one weight portion is disposed in one compartment, a height of the support wall portion extending in a direction perpendicular to the membrane portion is greater than a height of the weight portion extending in a direction perpendicular to the membrane portion; A soundproof structure, characterized in that each of the weight portions constitutes a spring-mass resonator having an elastic spring portion and a mass portion having a mass greater than that of the spring portion. [2] The soundproof structure described in [1], wherein the membrane portion, the support wall portion, and the spring portion are all made of either 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. [3] The soundproof structure according to [1] or [2], wherein the membrane portion, the support 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 a frequency of 1 Hz to 1000 Hz. [4] A soundproof structure according to any one of [1] to [3], wherein the film portion, the support 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. [5] A soundproof structure described in any one of [1] to [4], wherein the spring portion is located on the side of the weight portion attached to the membrane portion, and the mass portion is located on the side opposite to the side of the weight portion attached to the membrane portion. [6] The vehicle is arranged at least in part at a position separating the space in which the front tires are accommodated from the passenger compartment, The device has an elastic membrane portion, an elastic support wall portion erected on the membrane portion, and a weight portion erected on the membrane portion, the membrane portion is divided into a plurality of compartments by the support wall portion, and the weight portion is located inside each of the plurality of compartments or inside some of the plurality of compartments, In the compartments in which the weight portions are located, one weight portion is disposed in one compartment, a height of the support wall portion extending in a direction perpendicular to the membrane portion is greater than a height of the weight portion extending in a direction perpendicular to the membrane portion; A soundproof structure, characterized in that the film portion serves as a spring portion and the weight portion serves as a mass portion, thereby forming a spring-mass resonator. [7] The soundproof structure described in [6], wherein both the membrane portion and the supporting wall portion are made of either 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. [8] The soundproof structure according to [6] or [7], wherein the film portion and the supporting wall portion each have a dynamic storage modulus of 0.01 MPa or more and 100 MPa or less at 23°C and a frequency of 1 Hz to 1000 Hz. [9] The soundproof structure according to any one of [6] to [8], wherein the film portion and the supporting wall portion each 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.

[10] A soundproof structure as described in any of [1] to [9], wherein the soundproof structure is formed to constitute part of a floor carpet laid from the floor surface of the vehicle compartment to a position that partially covers the space, or is sandwiched between the floor carpet and a panel that partially covers the space or an automotive component placed on the panel.

[11] A soundproof structure according to any one of [1] to

[10] , which is arranged inside an electric vehicle. [Explanation of symbols]

[0091] 1 Floor carpet 1a Soundproof structure 2 Membrane part 3 Support wall section 3a 1st wall 3b 2nd wall part 4 Weight part 4a Spring part 4b Mass part 5 plots 6 Soundproofing structure 7 Weight 8 Floor carpet 10 Dash insulator (automotive parts) 11 Front tire 12 Space for accommodating front tire 13 Cabin 14 Panels 15 sheets P crew

Claims

1. The vehicle is disposed at least in part at a position separating a space for accommodating front tire from a passenger compartment, The device has an elastic membrane portion, an elastic support wall portion erected on the membrane portion, and a weight portion erected on the membrane portion, the membrane portion is divided into a plurality of compartments by the support wall portion, and the weight portion is located inside each of the plurality of compartments or inside some of the plurality of compartments, In the compartments in which the weight portions are located, one weight portion is disposed in one compartment, a height of the support wall portion extending in a direction perpendicular to the membrane portion is greater than a height of the weight portion extending in a direction perpendicular to the membrane portion; A soundproof structure, characterized in that each of the weight portions constitutes a spring-mass resonator having an elastic spring portion and a mass portion having a mass greater than that of the spring portion.

2. 2. The soundproof structure of claim 1, wherein the membrane portion, the support wall portion, and the spring portion are all made of 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.

3. 3. The soundproof structure according to claim 1, wherein the membrane portion, the support 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 a frequency of 1 Hz to 1000 Hz.

4. 4. The soundproof structure according to claim 3, wherein the film portion, the support 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.

5. 3. The soundproof structure according to claim 1, wherein the spring portion is located on the side of the weight portion attached to the membrane portion, and the mass portion is located on the opposite side of the weight portion from the side attached to the membrane portion.

6. The vehicle is disposed at least in part at a position separating a space for accommodating front tire from a passenger compartment, The device has an elastic membrane portion, an elastic support wall portion erected on the membrane portion, and a weight portion erected on the membrane portion, the membrane portion is divided into a plurality of compartments by the support wall portion, and the weight portion is located inside each of the plurality of compartments or inside some of the plurality of compartments, In the compartments in which the weight portions are located, one weight portion is disposed in one compartment, a height of the support wall portion extending in a direction perpendicular to the membrane portion is greater than a height of the weight portion extending in a direction perpendicular to the membrane portion; A soundproof structure, characterized in that the film portion serves as a spring portion and the weight portion serves as a mass portion, thereby forming a spring-mass resonator.

7. 7. The soundproof structure according to claim 6, wherein the membrane portion and the support wall portion are made of 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.

8. 8. The soundproof structure according to claim 6, wherein the film portion and the supporting wall portion each have a dynamic storage modulus of 0.01 MPa or more and 100 MPa or less at 23° C. and a frequency of 1 Hz to 1000 Hz.

9. 9. The soundproof structure according to claim 8, wherein the film portion and the support wall portion each 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.

10. 10. The soundproof structure according to claim 1, wherein the soundproof structure is formed so as to constitute part of a floor carpet laid from the floor surface of the vehicle compartment to a position that partially covers the space, or is sandwiched between the floor carpet and a panel that partially covers the space or an automotive component placed on the panel.

11. The soundproof structure according to claim 1 or 6, which is disposed inside an electric vehicle.

Images