Sound insulation member, sound insulation sheet member, and sound insulation structure equipped therewith

Abstract

Provided are a sound-insulating sheet member and a sound-insulating structure that comprises the sound-insulating sheet member that can be installed where there is limited installation space and are capable of low-frequency sound insulation.　A sound-insulating sheet member according to the present invention includes a sheet that has rubber elasticity and one or more protrusions that have rubber elasticity and are provided to at least one surface of the sheet. There is a space at at least a portion of the periphery of the protrusions, and the protrusions have a slit at a tip-side inner wall surface thereof.

Description

Sound-insulating sheet member and sound-insulating structure including the same

[0001] The present invention relates to a sound-insulating sheet member and a sound-insulating structure including the same.

[0002] Buildings such as apartment complexes, office buildings, and hotels require quietness suitable for indoor use by blocking outdoor noise from automobiles, trains, airplanes, ships, and the like, as well as equipment noise and human voices generated inside the building. Furthermore, vehicles such as automobiles, trains, airplanes, and ships require reducing indoor noise by blocking wind noise and engine noise to provide a quiet and comfortable space for occupants. Therefore, research and development has been conducted on means for blocking the transmission of noise and vibration from the outdoors to the interior, or from the exterior of a vehicle to the interior, i.e., vibration-damping means and sound-insulating means. In recent years, lightweight vibration-damping and sound-insulating members are required for buildings due to the increasing number of taller buildings, and lightweight vibration-damping and sound-insulating members are also required for vehicles to improve energy efficiency. Furthermore, to increase the design flexibility of buildings, vehicles, and their facilities, vibration-damping and sound-insulating members that can accommodate complex shapes are required.

[0003] Generally, the properties of sound-insulating materials, which reduce transmitted sound by reflecting sound, follow the so-called mass law. That is, the transmission loss, which is an indicator of the amount of noise reduction, is determined by the logarithm of the product of the mass of the sound-insulating material and the frequency of the elastic wave or sound wave. Therefore, in order to increase the amount of noise reduction at a certain frequency, the mass of the sound-insulating material must be increased. However, increasing the mass of the sound-insulating material limits the amount of noise reduction due to the mass constraints of buildings, vehicles, etc.

[0004] To solve the problem of increased mass of sound-insulating members, improvements have been made to the structure of the members, such as a method of combining multiple rigid flat plates such as gypsum board, concrete, steel plate, glass plate, or resin plate, or a method of forming a hollow double-wall structure or hollow triple-wall structure using gypsum board or the like.

[0005] In addition, the present applicants have previously proposed a sound-insulating sheet member that includes a rubber-elastic sheet and a resonating portion that includes a base and a weight portion in order to achieve sound-insulating performance that surpasses the mass law (Patent Document 1).

[0006] International Publication No. 2017 / 135409

[0007] The sound-insulating sheet member described in Patent Document 1 has a high degree of design freedom and is highly versatile. However, there are design limitations that can be achieved by simply changing the size or material of the resonating part, making it difficult to apply the sheet member to places with limited installation space or to soundproof low frequencies.

[0008] The present invention has been made in view of the above background art, and has an object to provide a sound-insulating sheet member and a sound-insulating structure including the same that can be installed in places with limited installation space and can insulate low-frequency sounds.

[0009] In addition to the objectives stated here, the present invention can also be positioned as another objective of achieving effects that cannot be obtained by conventional technologies, which are derived from the various components shown in the detailed description of the invention described below.

[0010] As a result of intensive research into solving the above-mentioned problems, the inventors discovered that the above-mentioned problems could be solved by providing a convex portion on a sheet having rubber elasticity and employing a sheet member in which a specific space portion is provided in the convex portion, and thus completed the present invention.

[0011] That is, the present invention provides various specific aspects as follows. [1] A sound-insulating sheet member comprising: a sheet portion having rubber elasticity; and at least one protruding portion having rubber elasticity, the protruding portion being provided on at least one surface of the sheet portion, the protruding portion having a space portion, and the protruding portion having a slit portion on an inner wall surface on a tip side of the protruding portion. [2] The sound-insulating sheet member according to [1] above, in which the slit portion is formed circumferentially on the inner wall on a tip side of the protruding portion. [3] The sound-insulating sheet member according to [2] above, in which the sheet portion has a space portion, and the space portion of the sheet portion is provided so as to penetrate from the surface of the sheet portion opposite to the side on which the protruding portion is provided to the space portion of the protruding portion. [4] The protruding portion is configured such that, at a natural frequency, the displacement field Z component of the outer periphery of the tip of the protruding portion is d Ｐ , the displacement field Z component at the center of the tip of the convex portion is d Ｑ When this is the case, d Ｐ / dＱ ≦0.8. [5] The sound-insulating sheet member according to [1], wherein the convex portion has a weight portion on the inner wall at the tip end thereof, and the slit portion is formed circumferentially around the weight portion. [6] The sound-insulating sheet member according to [5], wherein the slit portion is formed circumferentially along the shape of the outer wall of the convex portion. [7] The sound-insulating sheet member according to any one of [2] to [6], wherein the area ratio occupied by the space portion is 90% or less in a cross section of the convex portion in the sheet portion planar direction, at which the area ratio is greatest. [8] The sound-insulating sheet member according to any one of [2] to [7], wherein the volume ratio occupied by the space portion in the convex portion is 10% or more. [9] The sound-insulating sheet member according to any one of [2] to [8], wherein a part of the space portion in the convex portion is provided so as to reach at least one of the tip surface and the side surface of the convex portion.

[10] The sound-insulating sheet member according to any one of [1] to [9], wherein a part of the space of the convex portion is provided so as to reach at least one of the tip surface and the side surface of the convex portion.

[11] The equivalent diameter D of the weight portion, which is expressed by the following formula: Ｗ The equivalent diameter D of the convex portion is expressed by the following formula Ｐ The ratio (D Ｐ / D Ｗ ) is 1.25 or more. Ｐ = 4A Ｐ / p Ｐ D Ｗ = 4A Ｗ / p Ｗ D Ｐ : Equivalent diameter of the convex part DW: Equivalent diameter of the weight part A Ｐ A: Area of ​​the region formed from the outer periphery of the cross section of the convex portion in the planar direction of the seat portion Ｗ : Area of ​​the region formed from the outer periphery of the cross section of the weight portion in the planar direction of the seat portion p Ｐ : The outer periphery length of the cross section of the convex portion in the planar direction of the seat portion p Ｗ : The length of the circumference of the cross section of the weight portion in the plane direction of the seat portion

[12] D represented by the following formula ＰThe ratio of the height of the convex portion to the thickness of the sheet portion (H / D Ｐ The sound-insulating sheet member according to

[10] or

[11] above, wherein D is 2.1 or less. Ｐ = 4A Ｐ / p Ｐ D Ｐ : Equivalent diameter of the convex part A Ｐ p: Area of ​​the region formed from the outer periphery of the cross section of the convex portion in the planar direction of the seat portion Ｐ : the length of the periphery of the cross section of the convex portion in the planar direction of the sheet portion

[13] The sound-insulating sheet member according to any one of

[10] to

[12] above, wherein at least a portion of the weight portion is embedded in the convex portion.

[14] The sound-insulating sheet member according to any one of [1] to

[13] above, which is an integrally molded product.

[15] A sound-insulating structure comprising at least the sound-insulating sheet member according to any one of [1] to

[14] above, and a support body that supports the sound-insulating sheet member.

[16] The sound-insulating structure according to

[15] above, wherein the sheet portion and the convex portion independently contain at least one selected from the group consisting of a thermosetting elastomer, a photocurable elastomer, and a thermoplastic elastomer.

[0012] According to the present invention, it is possible to provide a sound-insulating sheet member and a sound-insulating structure including the same, which can be installed in places with limited installation space and can insulate low-frequency sounds.

[0013] 7 is a schematic perspective view showing a sound-insulating sheet member of the first embodiment. A cross-sectional view taken along the arrows II-II in FIG. 1. A cross-sectional view of the sound-insulating sheet member of the first embodiment. A cross-sectional view of the sound-insulating sheet member showing one aspect of a space. A diagram showing a simple model illustrating the operating principle of the sound-insulating structure of the present embodiment. A diagram showing a simple model illustrating the operating principle of the sound-insulating structure of the present embodiment. A schematic perspective view showing a sound-insulating sheet member of the second embodiment. A cross-sectional view taken along the arrows II-II in FIG. 7. A cross-sectional view of the sound-insulating sheet member showing one aspect of a space. A diagram for explaining a longitudinal extension vibration mode and a trampoline vibration mode. A diagram showing a simple model illustrating the operating principle of the sound-insulating structure of the present embodiment. A diagram showing a simple model illustrating the operating principle of the sound-insulating structure of the present embodiment. A schematic perspective view showing a sound-insulating structure including the sound-insulating sheet member of the first embodiment. A schematic perspective view showing a sound-insulating structure including the sound-insulating sheet member of the second embodiment. A cross-sectional view of an example of a support body, and a sound-insulating structure including the support body and the sound-insulating sheet member. A schematic configuration diagram of a unit cell used in calculating the natural frequency. A schematic configuration diagram of a unit cell without a weight portion. A graph showing the results of a protrusion vibration experiment in the examples. A graph showing the results of a protrusion vibration experiment in the examples.

[0014] Hereinafter, each embodiment of the present invention will be described with reference to the drawings. Note that the following embodiments are examples for explaining the present invention, and the present invention is not limited to these embodiments. Furthermore, hereinafter, unless otherwise specified, positional relationships such as up, down, left, and right will be based on the positional relationships shown in the drawings. Furthermore, the dimensional ratios of the drawings are not limited to the ratios shown. Note that in this specification, the notation of a numerical range, for example, "1 to 100," includes both the lower limit "1" and the upper limit "100." The same applies to notations of other numerical ranges.

[0015] <Sound-insulating sheet member> A sound-insulating sheet member (also simply referred to as a "sound-insulating sheet member") according to one embodiment of the present invention is a sound-insulating sheet member comprising a sheet portion having rubber elasticity and at least one convex portion having rubber elasticity provided on at least one surface of the sheet portion, with a space in at least a portion of the area surrounding the convex portion and a slit in the inner wall surface at the tip end of the convex portion. Specific aspects of this embodiment will be described below with reference to the drawings, but the present invention is not limited thereto. In this specification, "plurality" means two or more.

[0016] <First embodiment> An example (first embodiment) of a sound-insulating sheet member according to this embodiment is shown in Fig. 1. The sound-insulating sheet member 100 shown in Fig. 1 has a sheet portion 11 having rubber elasticity and at least one protruding portion 21 having rubber elasticity provided on one surface of the sheet portion 11, and at least the protruding portion 21 has a space portion 12. The sheet portion 11 has a sheet surface 11a and a sheet surface 11b. Fig. 2 is a cross-sectional view taken along the line I-I in Fig. 1.

[0017] The sound-insulating sheet member 100 shown in FIG. 2 has a configuration in which both the sheet portion 11 and the protruding portion 21 have a space 12. The protruding portion 21 is composed of the space 12 and a convex forming portion 22 surrounding the space 12 to form a convex shape. The space 12 is composed of a space 12r and a slit portion (also referred to as "space 12t") in the protruding portion 21, and a space 12s in the sheet portion. The space 12t is formed on the tip-side inner wall surface 22', which is the inner wall surface on the tip side of the protruding portion 21 (opposite the sheet portion 11). The formation of the space 12t facilitates trampoline vibration, as described below, and contributes to low-frequency sound insulation and a low profile. The dotted line B in FIG. 2 indicates the boundary between the sheet portion 11 and the protruding portion 21. 2, t1 is the height of the protrusion 21, t2 is the thickness of the sheet portion 11, t3 is the height of the space 12t (groove depth of the slit), w1 is the width of the protrusion 21, w2 is the cross-sectional width of the space 12 in the planar direction of the sheet portion, and w3 is the cross-sectional width of the space 12t. Also, dotted line C in Fig. 2 is a line indicating the boundary between the space 12t and the space 12r.

[0018] The region of the sheet portion 11 where the convex portion 21 is provided is the region of the sheet portion 11 that overlaps with the convex portion 21 when the sound-insulating sheet member 100 is viewed in plan, and in Figure 2 is the region of the sheet portion 11 having the width indicated by w1. Furthermore, in this specification, the space portion 12 is treated as a general term for the space portion 12r, the space portion 12s, and the space portion 12t. In other words, the space portion 12 in the description of the convex portion 21 refers to the space portion 12r and the space portion 12t, the space portion 12 in the description of the sheet portion 11 refers to the space portion 12s, and the description of the space portion 12 unless otherwise distinguished applies to any of the space portion 12r, the space portion 12s, and the space portion 12t.

[0019] Examples of embodiments of the sound-insulating sheet member 100 are shown in Figures 3(a) to (d). The sound-insulating sheet member 100 shown in Figure 3(a) is an embodiment in which both the sheet portion 11 and the convex portions 21 have spaces 12, as in Figure 2. The sound-insulating sheet member 100 shown in Figure 3(b) is an embodiment in which only the convex portions 21 have spaces 12. The sound-insulating sheet member 100 shown in Figure 3(c) is an embodiment in which both the sheet portion 11 and the convex portions 21 have spaces 12, and the spaces 12 are provided so as to penetrate from the surface of the sheet portion 11 opposite the side on which the convex portions 21 are provided to the spaces 12 in the convex portions 21. From the viewpoint of achieving both ease of molding and sound-insulating performance, this embodiment is preferred. The sound-insulating sheet member 100 shown in Figure 3(d) has a configuration similar to that of the sound-insulating sheet member 100 in Figure 3(c) above, and has a cross-sectional width w2-2 of the space 12s of the sheet portion in the planar direction of the sheet portion that is smaller than the cross-sectional width w2-1 of the space 12r of the convex portion in the planar direction of the sheet portion. Furthermore, when the convex portion has a space, the convex portion may not have a through-hole connecting the space to the outside. This through-hole is a through-hole that directly connects the convex portion to the outside, and does not include a through-hole that connects the space of the convex portion to the outside via the sheet portion, as shown in Figure 3(c). From the viewpoint of improving sound insulation performance, this embodiment is preferred.

[0020] In this sound-insulating sheet member 100, for example, when sound waves are incident from a noise source on the sheet portion 11 side, vibrations occur in the sheet portion 11 and / or the convex portions 21. When the frequency of the incident sound waves and the natural frequency of the convex portions 21 are close to or coincident with each other, the convex portions resonate and vibrate violently. At this time, two forces acting on the sheet portion 11—1) the force generated by the sound waves and 2) the force generated by the vibration of the convex portions 21—are in opposite directions, suppressing the vibration of the sheet portion 11. As a result, high sound-insulating performance that surpasses the mass law is achieved. The sound-insulating sheet member 100 according to this embodiment achieves good sound-insulating performance at a smaller size than typical sound-insulating members, making it easy to reduce its height. Furthermore, the size and shape of the convex portions, spaces, and sheet portion can be appropriately adjusted depending on the installation environment and conditions, allowing it to be installed in places with limited installation space. Each component of the sound-insulating sheet member 100 is described in detail below.

[0021] [Sheet portion] The sheet portion 11 is a sheet portion having rubber elasticity, and its form is not particularly limited, but it may have rubber elasticity due to molecular motion of a resin (organic polymer), etc. This sheet portion 11 can also function as an oscillator (resonator) that vibrates at a certain frequency when sound waves are incident from a noise source. The sheet portion 11 may have a space portion 12. The space portion 12 may be integrated with the space portion of the protrusion 21 as shown in FIG. 3( a).

[0022] From the viewpoint of imparting rubber elasticity to the sheet portion, it is preferable that the material constituting the sheet portion 11 contains at least one selected from the group consisting of a thermosetting elastomer, a photocurable elastomer, and a thermoplastic elastomer. When manufacturing by casting using a metal mold or the like, it is necessary to fill the cavity on the mold surface with an elastomer, but a photocurable elastomer is preferable because it can fill the cavity in a liquid state with a relatively low viscosity before curing, thereby increasing the filling rate.

[0023] Specific examples of materials constituting the sheet portion 11 include: thermosetting resin elastomers such as vulcanized thermosetting resin elastomers such as chemically crosslinked natural rubber or synthetic rubber, urethane thermosetting resin elastomers, silicone thermosetting resin elastomers, fluorine thermosetting resin elastomers, and acrylic thermosetting resin elastomers; photocurable elastomers such as acrylic photocurable elastomers, silicone photocurable elastomers, and epoxy photocurable elastomers; and thermoplastic elastomers such as olefin thermoplastic elastomers, styrene thermoplastic elastomers, PVC thermoplastic elastomers, urethane thermoplastic elastomers, ester thermoplastic elastomers, amide thermoplastic elastomers, silicone thermoplastic elastomers, and acrylic thermoplastic elastomers.

[0024] Further specific examples of the thermosetting elastomer, photocurable elastomer, and thermoplastic elastomer include rubber. Specific examples include natural rubber, isoprene rubber, butadiene rubber, styrene-butadiene rubber, chloroprene rubber, nitrile rubber, polyisobutylene rubber, ethylene-propylene rubber, chlorosulfonated polyethylene rubber, acrylic rubber, fluororubber, epichlorohydrin rubber, polyester rubber, urethane rubber, silicone rubber, and modified products thereof, but are not particularly limited to these. These may be used alone or in combination of two or more.

[0025] Among these, natural rubber, isoprene rubber, butadiene rubber, styrene-butadiene rubber, chloroprene rubber, nitrile rubber, polyisobutylene rubber, ethylene propylene rubber, chlorosulfonated polyethylene rubber, acrylic rubber, fluororubber, epichlorohydrin rubber, polyester rubber, urethane rubber, silicone rubber, and modified products thereof are preferred, with silicone rubber, acrylic rubber, or modified products thereof being more preferred. Use of these materials tends to result in excellent heat resistance and cold resistance.

[0026] As long as the sheet portion 11 has so-called rubber elasticity, it may contain various additives such as a flame retardant, an antioxidant, a plasticizer, or a colorant. Flame retardants are additives blended into flammable materials to make them less flammable or to prevent them from igniting. Specific examples of flame retardants include bromine compounds such as pentabromodiphenyl ether, octabromodiphenyl ether, decabromodiphenyl ether, tetrabromobisphenol A, hexabromocyclododecane, and hexabromobenzene; phosphorus compounds such as triphenyl phosphate; chlorine compounds such as chlorinated paraffins; antimony compounds such as antimony trioxide; metal hydroxides such as aluminum hydroxide; nitrogen compounds such as melamine cyanurate; and boron compounds such as sodium borate, but are not limited to these.

[0027] The antioxidant is an additive incorporated to prevent oxidative degradation. Specific examples thereof include, but are not limited to, phenolic antioxidants, sulfur-based antioxidants, and phosphorus-based antioxidants. Furthermore, the plasticizer is an additive incorporated to improve flexibility and weather resistance. Specific examples thereof include, but are not limited to, phthalate esters, adipate esters, trimellitate esters, polyesters, phosphate esters, citric acid esters, sebacate esters, azelaic acid esters, maleate esters, silicone oils, mineral oils, vegetable oils, and modified forms thereof. Furthermore, colorants include dyes and pigments. These various additives can be used alone or in combination of two or more.

[0028] 1, the sheet portion 11 is formed in a square shape in plan view, but the shape is not particularly limited to this. Any shape in plan view can be adopted, such as a triangular shape, a rectangular shape, a trapezoidal shape, a diamond shape, a polygonal shape such as a pentagonal shape or a hexagonal shape, a circular shape, an elliptical shape, or an irregular shape not classified into any of these.

[0029] The thickness t2 of the sheet portion 11 is not particularly limited and can be set as appropriate. If the thickness t2 of the sheet portion 11 is thick, the natural frequency of the convex portions 21 tends to shift toward lower frequencies. Conversely, if the thickness t2 of the sheet portion 11 is thin, the natural frequency of the convex portions 21 tends to shift toward higher frequencies. From the viewpoints of sound insulation performance, mechanical strength, flexibility, and handleability, the thickness of the sheet portion 11 is preferably 10 μm or more, more preferably 50 μm or more, and even more preferably 100 μm or more. The thickness of the sheet portion 11 is preferably 2 mm or less, more preferably 1 mm or less, and even more preferably 500 μm or less. The thickness of the sheet portion 11 does not have to be uniform throughout the entire sheet portion. For example, depending on the manner in which the sound-insulating sheet member 100 is installed or when it is desired to vary the sound insulation performance in certain areas, the sheet portion may be inclined within the range that is recognized as a sheet. If the thickness of the sheet portion 11 is not uniform, the thickness t2 of the sheet portion 11 is calculated as an average value. However, from the viewpoint of ease of molding and ensuring stable sound insulation performance, it is preferable that the thickness of the sheet portion 11 is uniform.

[0030] From the viewpoints of sound insulation performance, mechanical strength, flexibility, handleability, productivity, etc., the sheet portion 11 preferably has a Young's modulus of 0.01 MPa or more, more preferably 0.1 MPa or more, and preferably 100 MPa or less, more preferably 10 MPa or less. Here, Young's modulus in this specification means the ratio of the force (stress) acting per unit cross-sectional area of ​​a sample when an external force is applied in one axial direction to the deformation rate (strain), and refers to the value of the storage modulus of elasticity at 25°C and 10 Hz measured by the forced vibration non-resonance method of JIS K 6394:2007 "Vulcanized rubber and thermoplastic rubber - Determination of dynamic properties -".

[0031] Furthermore, from the viewpoint of reducing the temperature dependency of sound insulation properties at low temperatures, the sheet portion 11 preferably has a glass transition temperature of 0°C or lower. The lower the glass transition temperature of the sheet portion 11, the higher the cold resistance becomes, and the temperature dependency of the elastic modulus around 0°C decreases, tending to make the sound insulation performance less dependent on the ambient temperature. The glass transition temperature of the sheet portion 11 is more preferably -10°C or lower, even more preferably -20°C or lower, and particularly preferably -30°C or lower. In this specification, the glass transition temperature of the sheet portion 11 refers to the peak temperature of the loss tangent in the dynamic viscoelasticity measurement, particularly the temperature dependency measurement, at a frequency of 10 Hz as described above.

[0032] [Convex Portion] At least one convex portion 21 is provided on the sheet portion 11 and functions as a vibrator (resonator) that vibrates at a certain frequency when sound waves are incident from a noise source. The convex portion 21 has a space 12. For example, as in the sound-insulating sheet member 100 shown in FIG. 2, the convex portion 21 may be composed of a space 12 continuing from the sheet portion 11 and a convex forming portion 22 surrounding the space 12. The convex portion 21 effectively functions as a resonator in which the tip portion of the convex forming portion 22, particularly the portion tipward of the space 12r, acts as a weight, and the rear end portion of the convex forming portion 22 acts as a spring. Unless otherwise specified, each parameter of the convex portion 21 described below represents the average value of the parameters of all the convex portions provided. The tip side portion of the convex portion 21 (convex forming portion 22) may be the area in the range generally recognized as the tip side, and specifically, it may be 50% of the area of ​​the entire area of ​​the convex portion 21 toward the tip side in the height direction of the convex portion 21, and if the convex portion has a space portion, it may also be the area toward the tip side of the sheet side end of the space portion, but it is preferable to define it as the latter from the viewpoint of ensuring that the effects of the present invention are obtained.

[0033] The convex portions 21 may be provided on at least one side of the sheet portion 11, and may be provided on only one side or both sides. However, from the viewpoint of improving sound insulation performance, it is preferable that the convex portions 21 be provided on only one side of the sheet portion 11. However, when a sound insulation structure is formed by providing a support (described later), it is preferable that the convex portions 21 be provided on only one side of the sheet portion 11 from the viewpoint of ease of manufacturing and stable performance. Note that, when convex portions are provided on both sides of the sheet portion, parameters related to the convex portions in this specification are treated as parameters of the convex portions provided on one side unless otherwise specified. For example, the conditions for the height of the convex portions described later apply to the parameters of the convex portions provided on one side of the sheet portion (or the average value if multiple convex portions are provided). Furthermore, the parameters of the sound insulation sheet member in this embodiment are treated as parameters of the entire sound insulation sheet, including all of the convex portions on both sides of the sheet portion.

[0034] The arrangement, number, size, etc. of the convex portions 21 can be set appropriately depending on the desired performance and are not particularly limited. The convex portions 21 are provided in contact with at least one surface of the sheet portion 11. For example, in the sound-insulating sheet member 100 shown in FIG. 1 , the multiple convex portions 21 are arranged at equal intervals in a grid pattern, but the arrangement of the convex portions 21 is not particularly limited to this. The multiple convex portions 21 may be arranged, for example, in a staggered pattern or randomly. Because the sound-insulating mechanism using the sound-insulating sheet member according to this embodiment does not utilize Bragg scattering like so-called phononic crystals, the convex portions 21 do not necessarily have to be arranged at regular, periodic intervals.

[0035] The number of protrusions 21 to be installed per unit area is not particularly limited as long as the protrusions 21 can be arranged so as not to interfere with each other due to contact, etc. The maximum number of protrusions 21 per unit area varies depending on the shape of the protrusions 21, etc. For example, if the protrusions 21 are cylindrical, the height direction of the cylinder is arranged parallel to the normal direction of the sheet, and the cross-sectional diameter of the cylinder is 1 cm, the maximum number of protrusions 21 per unit area is 100 cm. 2 The minimum number of the protrusions 21 per unit area is preferably 100 or less. For example, when the protrusions 21 are cylindrical and are arranged so that the height direction of the cylinder is parallel to the normal direction of the sheet, and the cross-sectional diameter is 1 cm, the minimum number of the protrusions 21 per unit area is 100 cm.2 The number of protrusions 21 provided per sheet is preferably one or more, more preferably 10 or more, and even more preferably 50 or more. When the number of protrusions 21 provided is equal to or greater than the above-mentioned preferable lower limit, higher sound insulation performance tends to be obtained. Furthermore, when the number is equal to or less than the above-mentioned preferable upper limit, it becomes easier to reduce the weight of the entire sheet.

[0036] The heights of the multiple protrusions 21 (the lengths in the normal direction of the sheet portion 11) may or may not be uniform, but are preferably uniform from the viewpoints of ease of molding and ensuring stable sound insulation performance. The height of the tallest protrusion among the multiple protrusions 21 (maximum height of the protrusions 21) can be set appropriately depending on the desired performance and is not particularly limited. From the viewpoints of ease of molding and improved productivity, the maximum height of the protrusions 21 is preferably 100 μm or more, more preferably 500 μm or more, and even more preferably 1 mm or more. Furthermore, it is preferably 50 mm or less, more preferably 40 mm or less, and even more preferably 30 mm or less. By setting the height within the above preferred numerical range, the releasability of the sheet 11 provided with the protrusions 21 (i.e., the sound insulation sheet member 100) tends to be improved.

[0037] In a plane parallel to the seat surface 11a of the seat portion 11 at a height position where the sum of the cross-sectional areas of the plurality of protrusions 21 is maximum, the cross-sectional area of ​​the protrusion having the largest area among the cross sections of the protrusions included in the plane is 8000 mm ２ It is preferable that the length is 2000 mm or less. ２ More preferably, it is 500 mm or less. ２ It is more preferable that the cross-sectional area of ​​the convex portion having the smallest area is 50 μm or less. ２ It is preferable that the thickness is 8000 μm or more. ２ More preferably, it is 0.15 mm or more. ２ More preferably, it is equal to or greater than this.

[0038] 1, when the protrusions are cylindrical, in a plane parallel to the seat surface 11a of the seat portion 11 at a height position where the sum of the cross-sectional areas of the multiple protrusions 21 is greatest, the diameter of the largest circle among the cross sections of the protrusions included in the plane is preferably 100 mm or less, more preferably 50 mm or less, and even more preferably 25 mm or less. The diameter of the smallest circle is preferably 10 μm or more, more preferably 100 μm or more, and even more preferably 1 mm or more. By setting the cross-sectional area of ​​the protrusions 21 and the diameter of the circle in the case of a cylinder within the above-mentioned preferred numerical ranges, it is possible to ensure that a predetermined number or more of protrusions 21 are installed on the seat surface 11a of the seat portion 11, thereby achieving even better sound insulation performance and tending to further improve molding ease and productivity.

[0039] Furthermore, at least one protrusion 21 is provided on at least one surface of the sheet portion 11, but the material constituting the protrusions 21, the arrangement, shape, size, installation direction of the protrusions 21, etc. do not necessarily have to be the same for all of the multiple protrusions 21. By providing multiple types of protrusions 21 that are different in at least one of these, an effect such as expanding the frequency range in which high sound insulation performance is exhibited may be obtained.

[0040] The cross-sectional shape of the convex portion 21 is not particularly limited, and any shape can be adopted, such as a triangular prism, a rectangular prism, a trapezoidal prism, a polygonal prism such as a pentagonal prism or a hexagonal prism, a cylindrical prism, an elliptical prism, a truncated pyramid, a truncated cone, a pyramid, a cone, a cylinder, or an irregular shape not classified as any of the above. From the viewpoint of productivity, a rectangular prism or a cylindrical shape is preferable. The shape can be appropriately selected depending on the application from the viewpoints of sound insulation performance, manufacturing cost, handleability, etc.

[0041] [Space portion] It is sufficient that the space portion 12 is provided at least in the convex portion 21, but in order to obtain good sound insulation performance, it is preferable that the space portion 12 be provided in both the convex portion 21 and the region of the sheet portion 11 where the convex portion 21 is provided, and it is particularly preferable that one space portion 12 be provided that is connected across both the convex portion 21 and the region of the sheet portion 11 where the convex portion 21 is provided. For example, as shown in Fig. 1 , a space portion 12 having a substantially cylindrical shape may be provided continuously in the sheet portion 11 and the convex portion 21. In this specification, the region that combines each convex portion and the region of the sheet portion where the convex portion is provided is also referred to as a "composite region."

[0042] The shape of the space 12 is not particularly limited, and may be any shape, such as a triangular prism, a rectangular prism, a trapezoidal prism, a polygonal prism such as a pentagonal prism or a hexagonal prism, a cylindrical prism, an elliptical prism, a truncated pyramid, a truncated cone, a pyramid, a cone, a cylinder, or an indeterminate shape not classified as any of the above. The number of spaces 12 in each composite region is not limited to one, and may be divided, for example, as shown in FIG. 4( a). The space 12 does not need to be composed of air alone. For example, as shown in FIG. 4( b), a sound-absorbing material 24 such as foam or nonwoven fabric may be provided inside the space 12 as long as it does not inhibit the resonance of the protrusion 21. As shown in FIG. 1, a slit-shaped space 12t may be formed continuously from the tip of the space 12r of the protrusion 21.

[0043] The space 12t is formed on the tip-side inner wall surface 22', which is the inner wall surface on the tip side of the protrusion 21 (opposite the seat portion 11). The shape of the space 12t, which is a slit portion, is not particularly limited, but is preferably formed circumferentially. By forming it circumferentially, the thickness of the protrusion forming portion 22 at the portion where the slit is formed becomes thinner, making it easier to generate trampoline vibration, which will be described later. The circumferential shape is not particularly limited, but it can be formed circumferentially, for example, along the cross-sectional shape of the protrusion 21. In FIG. 1, the cross-sectional shape of the protrusion 21 is cylindrical, and the circumferential shape of the slit (space 12t) is also cylindrical.

[0044] The slit depth t3 is in the range of 99% or less of the height t1 of the convex portion 21, and preferably 85% or less of t1. If the slit depth t3 is more than 0% of the height t1 of the convex portion 21, the effect of lowering the natural frequency or reducing the profile can be obtained. However, for ease of manufacturing, it is preferably 0.05 mm or more, and more preferably 0.1 mm or more. The cross-sectional width w3 of the space portion 12 in the planar direction of the seat portion is in the range of 99% or less of the width w1 of the convex portion 21, and preferably 45% or less of w1. If the cross-sectional width w3 of the space portion 12 in the planar direction of the seat portion is more than 0% of the width w1 of the convex portion 21, the effect of lowering the natural frequency or reducing the profile can be obtained. However, for ease of manufacturing, it is preferably 0.05 mm or more, and more preferably 0.1 mm or more.

[0045] The sound-insulating sheet member 100 can obtain the effect of lowering the natural frequency or reducing the height by having a space portion, but further, as shown in Figure 3 (c) or Figure 3 (d), by configuring at least the sheet portion 11 to have a space portion 12 and having a portion of the space portion 12 reach the surface of the sheet portion 11 opposite the side on which the convex portion 21 is provided, further effects described below can be obtained.

[0046] When the sound-insulating sheet member 100 is provided on a support that supports the member, air may become trapped between the sheet portion 11 and the adherend. However, if the sound-insulating sheet member 100 is configured in such a manner that at least the sheet portion 11 has a space 12 and that part of the space 12 reaches the surface of the sheet portion 11 opposite the side on which the protrusions 21 are provided, as shown in Figure 3(c) or 3(d), a space exists in part of the contact area between the sound-insulating sheet member and the support, allowing air pockets to escape into the space and allowing adhesive to fill between the sound-insulating sheet member 100 and the adherend. This prevents the sound-insulating sheet member 100 from peeling off, resulting in superior stability compared to when there is no space in part of the contact area between the sound-insulating sheet member and the support.

[0047] Furthermore, when adhesive is applied to bond the sound-insulating sheet member and the support, the thickness of the adhesive may become uneven. However, with the sound-insulating sheet member 100 shown in Fig. 3(c) or 3(d), excess adhesive can escape into the recess under the sheet when leveling the thickness of the adhesive, making it possible to make the thickness of the adhesive layer uniform.

[0048] 3(c), there is no portion where the cross-sectional area of ​​the space 12 increases from the surface of the sheet portion 11 on the side opposite to the side where the protrusions 21 are provided to the space 12, which has the advantage of facilitating manufacturing. Since there is no portion where the cross-sectional area increases in this way, a manufacturing method using a mold having a concave shape and a mold having a convex shape can be used.

[0049] Furthermore, by forming the spaces 12 at positions corresponding to the convex portions on the sheet surface opposite to the convex portions 21, it is possible to lower the natural frequency of the convex portions 21 or reduce the height of the convex portions 21. Here, compared to convex portions 21 that do not have the spaces 12, this means that the natural frequency can be lowered when comparing the natural frequency with the same convex outer shape, and the height can be reduced when comparing the height with the convex shape that results in the same natural frequency. The effects are similar, and will be described in detail below.

[0050] This feature can be described using a spring-mass model in which the protrusion 21 is expressed as a resonator with a spring portion as a unit, as shown in Figure 5. The arrow in Figure 5 indicates the resonance direction. In Figure 5, the portion (mass) indicated by a circle corresponds to the tip side of the protrusion 21, particularly the portion of the protrusion 21 that is tip side of the space 12, the spring notation indicates the rear end portion of the protrusion 21, particularly the protruding portion 22 around the space 12 in cases where the protrusion 21 has a space 12 that reaches the seat portion 11, and the rectangular portion indicates the adherend. Here, if the mass of the tip side portion of the protrusion 21 is M and the spring constant of the rear end portion of the protrusion 21 is K, the natural frequency of the protrusion 21 is f∝(K / M). １／２ It can be seen that the natural frequency f of the protrusion 21 is proportional to the 1 / 2 power of the spring constant K.

[0051] In order to clarify the correspondence between the above spring mass model, the shape of the convex part, and the material properties, an explanation will be given using the model shown in Figure 6. First, let us assume that the convex part 21 is a rod-shaped spring with no space such as a cylinder or a rectangular pillar, and with a constant cross-sectional area of ​​the protrusion. In this case, the relationship between the load F and the elongation L of the rod-shaped spring is expressed by the following formula. The arrow in Figure 6 indicates the resonance direction. ΔF = (EAΔL / L) E (MPa): storage modulus A (mm2): cross-sectional area of ​​the convex part L (mm): height of the resin spring part ΔL (mm): elongation when load F is applied

[0052] In the above equation, the spring constant K is expressed as K = EA / L due to the relationship ΔF / ΔL = K. Therefore, it can be seen that the spring constant K is proportional to the cross-sectional area A of the convex portion 21. As described above, the natural frequency f of the convex portion 21 is proportional to the 1 / 2 power of the spring constant K, and therefore it can be seen that the natural frequency f of the convex portion 21 is proportional to the 1 / 2 power of the cross-sectional area A of the convex portion 21. Here, when the convex portion 21 has the space portion 12, the cross-sectional area A of the convex portion 21 becomes smaller in proportion to the proportion of the space portion 12, and therefore the natural frequency f of the convex portion 21 also decreases. Therefore, the presence of the space portion 12 can lower the natural frequency of the convex portion 21.

[0053] Furthermore, from the relationship K = EA / L, it can be seen that the spring constant K is inversely proportional to the height L of the resin spring portion. In other words, to lower the frequency by adjusting the outer shape of the convex portion, the height of the convex portion 21 must be increased. On the other hand, since the frequency can be lowered by providing the space portion 12 as described above, there is no need to change the height of the convex portion 21, and the height of the convex portion 21 can be reduced.

[0054] The ratio of the space 12 to the sheet portion 11 and the protrusions 21 is not particularly limited as long as it satisfies the range of this embodiment. The ratio of the space 12 can be appropriately set so that the natural frequency of the protrusions 21 matches the desired sound insulation frequency range. If the ratio of the space 12 is large, the natural frequency of the protrusions 21 tends to shift significantly to the low frequency side, but the ratio of the protrusion-forming portions 22 decreases, thereby reducing the strength of the protrusions 21. On the other hand, if the ratio of the space 12 is small, the ratio of the protrusion-forming portions 22 increases, thereby increasing the strength of the protrusions 21, but the shift of the natural frequency of the protrusions 21 to the low frequency side tends to be smaller.

[0055] The proportion of the area of ​​the space 12 in the horizontal cross section of the protrusion 21 at which the proportion is greatest is preferably 20% or more, more preferably 30% or more, and even more preferably 40% or more, from the viewpoint of sound insulation performance. Moreover, from the viewpoints of mechanical strength, handleability, etc., this proportion is preferably 90% or less, more preferably 85% or less, and even more preferably 80% or less.

[0056] From the viewpoint of sound insulation performance, the volume ratio of the spaces 12 in the convex portions 21 is preferably 10% or more, more preferably 20% or more, even more preferably 30% or more, and preferably 80% or less, more preferably 75% or less, and even more preferably 70% or less. Also, from the viewpoint of sound insulation performance, the volume ratio of the spaces 12 in the composite region, which is the region combining each convex portion 21 and the region in which the convex portion 21 is provided in the sheet portion 11, is preferably 10% or more, more preferably 20% or more, even more preferably 30% or more, and preferably 80% or less, more preferably 75% or less, and even more preferably 70% or less.

[0057] [Convex-forming portion] At least one convex-forming portion 22 is provided in contact with the sheet surface 11 a of the sheet portion 11, and is provided around the space portion 12 to form a convex shape. The outer shape and outer parameters of the convex-forming portion 22 are the same as the outer shape and outer parameters of the convex portion 21 described above.

[0058] The material of the convex-forming portion 22 (convex portion 21) is not particularly limited as long as it satisfies the required characteristics, and may be the same as or different from the material of the sheet portion, and the materials can be selected independently. For example, at least one selected from the group consisting of a thermosetting elastomer, a photocurable elastomer, a thermoplastic elastomer, a thermosetting resin, a photocurable resin, and a thermoplastic resin can be used.

[0059] Among these, from the viewpoint of imparting rubber elasticity, thermosetting elastomers, photocurable elastomers, and thermoplastic elastomers are preferred, and examples of such elastomers include those exemplified for the sheet portion 11. Examples of thermosetting resins or photocurable resins include acrylic thermosetting resins, urethane thermosetting resins, silicone thermosetting resins, and epoxy thermosetting resins. Examples of thermoplastic resins include polyolefin thermoplastic resins, polyester thermoplastic resins, acrylic thermoplastic resins, urethane thermoplastic resins, and polycarbonate thermoplastic resins.

[0060] Specific examples of the resin include polymers such as polyacrylonitrile, polyethylene terephthalate, polybutylene terephthalate, polyvinyl chloride, polychlorotrifluoroethylene, polyethylene, polypropylene, polynorbornene, polyether ether ketone, polyphenylene sulfide, polyarylate, polycarbonate, polystyrene, epoxy resin, and oxazine resin, but are not particularly limited to these.

[0061] Specific examples of elastomers include vulcanized rubber such as chemically crosslinked natural rubber or synthetic rubber, isoprene rubber, butadiene rubber, styrene-butadiene rubber, chloroprene rubber, nitrile rubber, polyisobutylene rubber, ethylene propylene rubber, chlorosulfonated polyethylene rubber, acrylic rubber, fluororubber, epichlorohydrin rubber, polyester rubber, urethane rubber, silicone rubber and modified products thereof, polyacrylonitrile, polyethylene terephthalate, polybutylene terephthalate, polyvinyl chloride, polychlorotrifluoroethylene, polyethylene, polypropylene, polynorbornene, polyether ether ketone, polyphenylene sulfide, polyarylate, polycarbonate, polystyrene, epoxy resin, oxazine resin, and the like, but are not particularly limited to these.

[0062] Among these, natural rubber, isoprene rubber, butadiene rubber, styrene-butadiene rubber, chloroprene rubber, nitrile rubber, polyisobutylene rubber, ethylene propylene rubber, chlorosulfonated polyethylene rubber, acrylic rubber, fluororubber, epichlorohydrin rubber, polyester rubber, urethane rubber, silicone rubber, and modified products thereof are preferred, and silicone rubber, acrylic rubber, and modified products thereof are more preferred from the viewpoint of excellent heat resistance and cold resistance, etc. The above materials can be used alone or in combination of two or more.

[0063] Among these, the material of the convex-forming portion 22 is preferably the same material as that of the sheet portion 11 described above, and elastomers are particularly preferred. If the sheet portion 11 and the convex-forming portion 22 contain the same elastomers, the sheet portion 11 and the convex-forming portion 22 can be easily molded integrally, dramatically improving productivity. In other words, one particularly preferred embodiment is when the sheet portion 11 and the convex portion 21 (convex-forming portion 22) are an integrally molded product that both contains at least one type selected from the group consisting of a thermosetting elastomer, a photocurable elastomer, and a thermoplastic elastomer.

[0064] The convex portion 22 may be a two-color molded body or a multi-color molded body made of two or more materials. In this case, by using the same elastomer as the sheet portion 11 for the convex portion 22 on the side (rear end side) that contacts the sheet portion 11, it becomes easy to integrally mold the sheet portion 11 and the convex portion 22.

[0065] Second Embodiment Another example (second embodiment) of the sound-insulating sheet member according to this embodiment is shown in Fig. 7. The sound-insulating sheet member 101 shown in Fig. 7 includes a sheet portion 11 having rubber elasticity and at least one protruding portion 21 having rubber elasticity and provided on one surface of the sheet portion 11, with at least the protruding portion 21 having a space 12 and further including a weight portion on the tip side of the protruding portion 21. Fig. 8 is a cross-sectional view taken along the arrows II-II in Fig. 7. This embodiment has the same configuration as the sound-insulating sheet member 100 of the first embodiment described above, except that a weight portion 23 is provided on the tip side of the protruding portion 21, and therefore a redundant description will be omitted here.

[0066] [Plummet] The weight 23 is not particularly limited as long as it has a density greater than that of the convex portion 22. The weight 23 in the sound-insulating sheet member 100 shown in FIG. 7 is formed in a generally cylindrical shape with a maximum diameter smaller than that of the convex portion 22 and is embedded in the convex portion 22 at the tip end of the convex portion 21. Because the weight 23, which functions as a weight for the resonator, is supported by the convex portion 22, which determines the spring constant, the natural frequency of the convex portion 21 can be controlled, for example, by changing the shape or material (elastic modulus, mass) of the convex portion 22 to adjust the spring constant or by changing the mass of the weight 23. Generally, as the elastic modulus of the convex portion 22 decreases, the natural frequency of the convex portion 21 tends to shift to a lower frequency. Furthermore, as the mass of the weight 23 increases, the natural frequency of the convex portion 21 tends to shift to a lower frequency.

[0067] The shape of the weight portion 23 is not particularly limited, but a plate-like shape is preferable in terms of adjusting the sound insulation performance and reducing the thickness. The plate-like shape of the weight portion 23 allows the center of gravity of the weight portion 23 to be positioned farther from the seat portion 11 than when the weight portion 23 is spherical or the like, which tends to increase the vibration moment of the convex portion 21. For example, when the vibration moment of the convex portion 21 is constant, the plate-like weight portion 23 can be made thinner than when the weight portion 23 is spherical or the like. On the other hand, when the height of the weight portion 23 is constant, a plate-like weight can obtain a larger vibration moment than when the weight portion 23 is spherical or the like. Furthermore, the weight portion 23 may have a through-hole, and examples of the shape of the through-hole include a donut shape, a washer shape, a nut shape, and the like.

[0068] The material for the weight portion 23 may be appropriately selected taking into consideration mass, cost, and the like, and the type of material is not particularly limited. From the viewpoint of miniaturizing the sound-insulating sheet member 101 and improving sound-insulating performance, the material for the weight portion 23 is preferably a material with a high specific gravity. Specific examples of the material for the weight portion 23 include, but are not limited to, metals or alloys such as aluminum, stainless steel, iron, tungsten, gold, silver, copper, lead, zinc, and brass; inorganic glasses such as soda glass, quartz glass, and lead glass; and composites containing powders of these metals or alloys or these inorganic glasses in the resin material of the convex-forming portion 22. The material, mass, and specific gravity of the weight portion 23 may be determined so that the natural frequency of the convex portion 21 matches the desired sound-insulating frequency range.

[0069] Among these, at least one selected from the group consisting of metals, alloys, and inorganic glasses is preferred from the viewpoints of low cost, high specific gravity, etc. Note that the specific gravity means the ratio of the mass of the material to the mass of pure water at 4°C under a pressure of 1013.25 hPa and the same volume, and in this specification, the value measured according to JIS K 0061 "Method for measuring density and specific gravity of chemical products" is used.

[0070] The surface of the weight portion 23 may be subjected to a surface treatment in order to improve process suitability and member strength. For example, it is possible to perform a chemical treatment using a solvent or the like to improve adhesion to the convex-forming portion 22, or to perform a physical treatment to increase member strength by providing irregularities on the surface, but the method of surface treatment is not particularly limited.

[0071] From the viewpoint of improving sound insulation performance, the volume ratio of the weight portion 23 in the convex portion 21 is typically 1 volume % or more, preferably 5 volume % or more, more preferably 10 volume % or more, and even more preferably 20 volume % or more, relative to 100 volume % of the convex portion, and is typically 90 volume % or less, preferably 80 volume % or less, more preferably 70 volume % or less, and even more preferably 50 volume % or less.

[0072] Although the weight 23 is embedded in the protruding portion 22 at the tip end side of the protruding portion 21 shown in FIG. 7 , its installation position is not particularly limited thereto. While it varies depending on the shape, mass, elastic modulus, etc. of the protruding portion 22 and the weight 23, from the viewpoint of reducing the thickness and weight of the sound-insulating sheet member 101 or improving the sound-insulating performance, it is preferable to position the protruding portion 22 and the weight 23 so that the center of gravity (center of mass) of the protruding portion 21 is located at least closer to the tip end than the center in the height direction of the protruding portion 21. Typically, the weight 23 is offset closer to the tip end than the center in the height direction of the protruding portion 21. The weight 23 may be completely embedded in the protruding portion 22 (protruding portion 21), or at least partially embedded, or may be provided on the protruding portion 22 without being embedded in the protruding portion 22. From the viewpoint of preventing the weight from falling off, it is preferable that at least a part of the weight 23 is embedded in the convex forming portion 22 (convex portion 21), and it is more preferable that the weight 23 is completely embedded. Furthermore, the shapes and heights of the multiple weights 23 included in the sound-insulating sheet member may be the same or different.

[0073] When the convex portion 21 has the weight portion 23, the space portion 12t, which is a slit portion, can be formed, for example, in a circumferential shape around the weight portion 23 so as to surround the weight portion 23. In this way, trampoline vibration can be effectively generated.

[0074] Furthermore, in the sound-insulating sheet member according to the second embodiment, when the convex portion 21 has a space 12, as shown in Figures 9(a) and 9(b), a part of the space 12 may be provided so as to reach at least one of the tip and side surface of the convex portion 21. This configuration is advantageous because it reduces the effect of the air inside on the resonance of the convex portion 21 compared to when air is sealed inside.

[0075] As shown in FIGS. 9(c) and 9(d), the protrusion 21 may have through holes on both the tip side and the sheet side.

[0076] The spring-mass model described above, which is expressed by a resonator having a spring portion as a unit, is a model for a longitudinal extension vibration mode, but below, a model for a trampoline vibration mode will be described. When the shape of the convex portion 21 having the space portion 12 satisfies certain conditions, the "trampoline vibration" which is a preferred vibration mode can be used to further lower the natural frequency of the convex portion 21 or to further reduce the height of the convex portion 21. In particular, the provision of the space portion 12t makes it easier for the trampoline vibration mode to occur, thereby making it possible to lower the natural frequency of the convex portion 21 or to reduce the height of the convex portion 21.

[0077] In this specification, the longitudinal stretching vibration refers to a mode in which the outer periphery P of the tip of the convex portion 21 and the center Q of the tip of the convex portion 21 vibrate up and down to the same extent, as shown in Fig. 10(a). In this specification, the trampoline vibration refers to a mode in which the center Q of the tip of the convex portion 21 vibrates up and down compared to the outer periphery P of the tip of the convex portion 21, as shown in Fig. 10(b). In this specification, as shown in Fig. 10, the displacement field Z component of the outer periphery P of the tip of the convex portion 21 in a certain vibration mode is defined as d Ｐ , the displacement field Z component of the center Q of the tip of the convex portion 21 is d Ｑ When this is the case, d Ｐ / d Ｑ ≦0.8, more preferably d Ｐ / d Ｑ The vibration mode that satisfies the condition ≦0.5 is defined as the trampoline vibration mode. The plane on which the seat part spreads is defined as the XY plane, and the direction perpendicular to the plane on which the seat part spreads is defined as the Z axis direction. The displacement field Z component d Ｐ and d Ｑ was obtained by calculating the natural vibration mode of the structure using COMSOL Multiphysics (manufactured by COMSOL), a physical simulation software using the finite element method. The conditions for this physical simulation will be described in detail in the explanation of <Experiment 3> below.

[0078] When trampoline vibration is occurring, the natural frequency can be lowered for the same height of the protrusions 21 compared to when vertical stretching vibration is occurring, and the height of the protrusions 21 that achieve the same natural frequency can be reduced (reduced in height). The effects are similar, and will be described in detail below.

[0079] This feature can be described using a spring-mass model in which the convex portion 21 is represented by a resonator having a spring portion as a unit, as shown in FIG. 11( a). The arrow in FIG. 11( a) indicates the resonance direction. Furthermore, when the convex portion 21 has a weight portion 23, in FIGS. 11( a) and 11( b), the portion (mass) indicated by a circle corresponds to the weight portion 23 on the tip side of the space 12 of the convex portion 21, the notation of a spring corresponds to a portion S (spring portion S) of the convex forming portion 22 on the tip side of the space 12 of the convex portion 21 that does not overlap with the weight portion 23 but overlaps with the space 12 when the sound insulation sheet member is viewed in a plane, and the portion (wall) indicated by a rectangle corresponds to a portion Q (square portion Q) consisting of a portion Q1 of the convex forming portion 22 that does not overlap with the space 12 when the sound insulation sheet member is viewed in a plane and a portion Q2 of the sheet portion 11 that overlaps with Q1 when the sound insulation sheet member is viewed in a plane. Here, if the mass of the weight portion 23 on the tip side of the space portion 12 of the convex portion 21 is M and the spring constant of the spring portion S is K, the natural frequency of the convex portion 21 is f∝(K / M). １／２ It can be seen that the natural frequency f of the protrusion 21 is proportional to the 1 / 2 power of the spring constant K.

[0080] In order to clarify the correspondence between the above spring mass model and the shape of the convex portion and the material properties, an explanation will be given using the model shown in Figure 12. First, let us assume that the shape of the portion consisting of the convex forming portion and weight portion 23 on the tip side of the space portion 12 of the convex portion 21 is a shape without a space portion such as a cylinder or a rectangular pillar, and that this convex forming portion is a rod-shaped spring with a constant cross-sectional area in the plane direction of the sheet portion. In this case, the relationship between the load F and the height L of the spring portion (extension of the spring portion) in the rod-shaped spring is expressed by the following formula. The white arrow in Figure 12 indicates the resonance direction, and the black arrow indicates the expansion / contraction direction. ΔF = (EAΔL / L) E (MPa): Storage modulus of spring portion S A (mm ２): Cross-sectional area of ​​a section perpendicular to the direction of expansion and contraction of a portion consisting of the weight portion 23 on the tip side of the space portion 12 of the convex portion 21 and the convex forming portion 22 on the tip side of the space portion 12 of the convex portion 21 L (mm): Length of the spring portion S in the expansion and contraction direction ΔL (mm): Elongation of the spring portion S in the expansion and contraction direction when a load F is applied

[0081] In the above equation, the spring constant K is expressed as K = EA / L due to the relationship ΔF / ΔL = K. By providing the space (slit) 12t, the cross-sectional area A in the above equation is reduced, which reduces the spring constant K and makes it possible to lower the natural frequency f of the convex portion 21. Furthermore, from the above equation, it can be seen that the spring constant K is inversely proportional to the length L of the spring portion S in the expansion / contraction direction. Here, when the diameter of the cross section of the convex portion 21 in the planar direction of the sheet portion increases, the length L of the spring portion S in the expansion / contraction direction increases, making it possible to lower the natural frequency f of the convex portion 21.

[0082] This tendency in the trampoline vibration mode is the opposite of that in the longitudinal stretching vibration mode model described above. In the longitudinal stretching vibration mode model, increasing the diameter of the cross section of the protrusion 21 in the planar direction of the seat increases the cross-sectional area A of the protrusion 21, which in turn increases K from the relationship K = EA / L, and shifts the natural frequency f of the protrusion 21 to a higher frequency.

[0083] Furthermore, in the longitudinal stretching vibration mode, if a lower frequency is achieved by changing the outer diameter shape of the convex portion 21, the height of the convex portion 21 must be increased, whereas in the trampoline vibration mode, a lower frequency is possible by increasing the diameter of the cross section of the convex portion 21 in the planar direction of the seat portion without changing the height of the convex portion 21. Therefore, even if the height of the convex portion 21 is lower than in the longitudinal stretching vibration mode, the same frequency can be achieved, and as a result, the height of the convex portion 21 can be reduced.

[0084] Trampoline vibration mode (d Ｐ / d Ｑ The structure of the convex portion 21 where the equivalent diameter D of the weight portion expressed by the following formula is likely to occur is a structure that satisfies the following (1) or (2), and more likely to occur is a structure that satisfies both of the following (1) and (2): ＷThe equivalent diameter D of the convex portion is expressed by the following formula Ｐ The ratio (D Ｐ / D Ｗ (2) The equivalent diameter D of the convex portion expressed by the following formula is 1.2 or more. Ｐ The ratio of the height H of the composite region (the total value of the height of the convex portion in the direction perpendicular to the plane direction of the sheet portion and the thickness of the sheet portion) to the height H (H / D Ｐ ) is 3.0 or less (more preferably 0.91 or less). Ｐ = 4A Ｐ / p Ｐ D Ｗ = 4A Ｗ / p Ｗ D Ｐ : Equivalent diameter of the convex part D Ｗ : Equivalent diameter of weight A Ｐ A: Area of ​​the region formed from the outer periphery of the cross section of the convex portion in the planar direction of the seat portion Ｗ : Area of ​​the region formed from the outer periphery of the cross section of the weight portion in the planar direction of the seat portion p Ｐ : The outer periphery length of the cross section of the convex portion in the planar direction of the seat portion p Ｗ : The length of the outer periphery of the cross section of the weight portion in the plane direction of the seat portion

[0085] If the outer diameter of the convex portion 21 is close to the outer diameter of the weight portion 23, only the weight portion 23 located on the tip side of the convex portion 21 cannot vibrate, and the vibration mode does not become the trampoline vibration mode. Also, if the height of the convex portion 21 is large relative to the outer diameter of the convex portion 21, only the weight portion 23 located on the tip side of the convex portion 21 cannot vibrate, and the vibration mode does not become the trampoline vibration mode.

[0086] [Sound-insulating structure] Another embodiment of the sound-insulating structure of the present invention (also simply referred to as "sound-insulating structure") includes at least the sound-insulating sheet member according to each of the above-described embodiments and a support member supporting the sound-insulating sheet member. The above-described sound-insulating sheet member can be installed appropriately depending on the environment in which sound-insulating performance is desired. For example, the sound-insulating sheet member may be installed directly on a device, structure, etc. An adhesive layer or the like may be provided between the sound-insulating sheet member and the device, structure, etc. Alternatively, as in this embodiment, the sound-insulating sheet member may be used together with a support member supporting the sound-insulating sheet member to form a sound-insulating structure. Note that the support member only needs to support the sound-insulating sheet member when the sound-insulating sheet member is used to insulate sound; it does not have to support the sound-insulating sheet member during manufacturing, storage, or other stages. An example of a sound-insulating structure is shown in Figures 13 and 14. Figure 13 shows a sound-insulating structure 200 including the sound-insulating sheet member 100 according to the first embodiment and a support member 51 supporting the sound-insulating sheet member 100. FIG. 14 shows a sound insulating structure 201 including the sound insulating sheet member 101 according to the second embodiment described above and a support body 51 that supports the sound insulating sheet member 101 .

[0087] [Support] The support is not particularly limited as long as it is provided on the sound-insulating sheet member. However, from the viewpoint of ease of manufacturing and structural stability, it is preferable that the support be provided in contact with the surface opposite to the surface on which the convex portions are provided in a sound-insulating sheet member having convex portions provided only on one side of the sheet member. Furthermore, when convex portions are formed on both sides of the sheet portion, a support with holes may be used and provided on the sheet surface on which the convex portions are provided, as shown in FIG. 15(a). The support shown in FIG. 15(a) may be provided on the side on which the convex portions are provided in a mode in which convex portions are provided only on one side of the sheet portion. A cross-sectional view of a sound-insulating sheet member having the support shown in FIG. 15(a) is shown.

[0088] The material constituting the support is not particularly limited as long as it can support the sound-insulating sheet member, but from the viewpoint of improving sound-insulating performance, it is preferable that the material be more rigid than the material constituting the sheet portion and the protrusions. Specifically, the support 51 preferably has a Young's modulus of 1 GPa or more, more preferably 1.5 GPa or more, and although there is no particular upper limit, it can be, for example, 1000 GPa or less. Furthermore, when the sound-insulating sheet member is directly installed on a device, structure, etc., it is preferable that the surface on which the sound-insulating sheet member is installed has the same rigidity as the support from the viewpoint of supporting the sheet and improving sound-insulating performance, etc.

[0089] Examples of materials constituting the support include a photocurable resin sheet, a thermosetting resin sheet, a thermoplastic resin sheet, a metal plate, an alloy plate, etc. Examples of the photocurable resin sheet, the thermosetting resin sheet, and the thermoplastic resin sheet include sheets using the photocurable resin, the thermosetting resin, and the thermoplastic resin listed in the sheet portion 11 above. Specific examples of materials constituting the support include polyester resins such as polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, and polybutylene succinate; poly(meth)acrylate resins such as polymethyl methacrylate; polycarbonate resins such as polycarbonate made primarily from isosorbide; polyolefin resins such as polyethylene, polypropylene, and polynorbornene; organic materials such as vinyl chloride resin, polyacrylonitrile, polyvinylidene chloride, polyethersulfone, polyphenylene sulfide, polyarylate, polyamide, polyimide, triacetyl cellulose, polystyrene, epoxy resin, and oxazine resin; and composite materials containing metals such as aluminum, stainless steel, iron, copper, zinc, and brass, inorganic glass, or inorganic particles or fibers in these organic materials.

[0090] Among these, from the viewpoints of sound insulation, rigidity, formability, cost, etc., the support is preferably at least one selected from the group consisting of a photocurable resin sheet, a thermosetting resin sheet, a thermoplastic resin sheet, a metal plate, and an alloy plate. Here, the thickness of the support is not particularly limited, but from the viewpoints of sound insulation performance, rigidity, formability, weight reduction, cost, etc., it is usually preferably 0.05 mm or more and 0.5 mm or less. Furthermore, from the viewpoints of light transmittance, adhesion to the sound insulation sheet member, etc., the support may have a coating layer provided on its surface.

[0091] The shape of the support body is not particularly limited and can be set appropriately depending on the installation surface of the sound-insulating structure. For example, the support body may be in the form of a flat sheet, a curved sheet, or a special shape processed to have curved or bent portions. Furthermore, from the viewpoint of weight reduction, etc., cuts, punched portions, etc. may be provided at any location on the support body.

[0092] The surface density of the support (mass per unit area) can also be set appropriately depending on the desired performance, and is not particularly limited. From the viewpoint of enhancing the effects of the present invention, the surface density of the support is preferably 80% or less of the surface density of the sound-insulating sheet member, more preferably 30% or less, and even more preferably 10% or less. There is no particular upper limit, but it may be, for example, 1% or more.

[0093] The sound-insulating structure may be a laminate including the sound-insulating sheet member of this embodiment. For example, sound-insulating sheet members may be provided on both sides of a support. Alternatively, multiple sound-insulating structures each having a sound-insulating sheet member provided on a support may be stacked and used. By combining multiple sound-insulating sheet members, it is possible to control the frequency position, etc. Furthermore, even in the case of a laminate having sound-insulating sheet members on both sides of a support, if the support, the housing including the laminate, etc. are flexible, it can conform to non-flat surfaces such as curved surfaces, and therefore the sound-insulating structure can be stably attached.

[0094] [Use of sound-insulating sheet members and sound-insulating structures] One example of how the sound-insulating sheet members and sound-insulating structures can be used is by attaching them to the inside or outside of small electronic devices to reduce or muffle motor noise and switching noise in electronic circuits.

[0095] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples. Various conditions can be adopted in the present invention as long as they do not deviate from the gist of the present invention and the object of the present invention is achieved.

[0096] <Experiment 1> [Calculation of Natural Frequency] In the examples described below, the natural frequency of the structure was calculated using COMSOL Multiphysics (manufactured by COMSOL), a physical simulation software using the finite element method. The conditions for this physical simulation are described in detail below. The finite element method was used for the physical simulation. The finite element method is a numerical analysis technique for approximately solving differential equations that cannot be solved analytically with high accuracy. It is a method of dividing a complex object to be analyzed into simple small parts (elements) and approximately calculating the overall behavior. The natural frequency of the protrusion in the examples described below was calculated using the following procedure. Figure 16 shows an embodiment in which a perforated nut (hexagonal plate) is used as the weight part. For each of the portions i to v of the sound insulation structure in Figure 16, the physical properties (specific gravity, storage modulus (Young's modulus), Poisson's ratio) listed in Table 1 and the material dimensions (r, h, a) listed in Table 1 and Figure 16 were substituted into the equations of the solid mechanics module of COMSOL Multiphysics (COMSOL), and the natural vibration mode was calculated under the condition that the bottom surface of sheet portion v was completely fixed. This calculation assumes an ideal state where there is no influence from the adhesive, so the natural frequency was calculated under the condition that the bottom surface of portion v was completely fixed.

[0097] The ratio of the area occupied by the space (part iii) in the horizontal cross section of the convex part at the cross section where the ratio is the largest is determined as follows: Space area ratio [%] = (radius of part iii) ２ / (radius of part i) ２Furthermore, in order to clarify the magnitude of the shift amount of the natural frequency due to the space portion (portion iii) and the slit portion (portion iv), the normalized shift amount of the natural frequency is defined as follows: Frequency shift amount [%] = ((natural frequency in an embodiment without portions iii and iv) - (natural frequency)) / (natural frequency in an embodiment without portions iii and iv).

[0098] <Aspects using a perforated nut (hexagonal plate) as the weight portion> [Examples 1 to 4] Examples 1 to 4 are unit cells including the sound-insulating sheet member shown in Fig. 16. The sizes, materials, and physical properties of the constituent members of the unit cell are shown in Table 1. The natural frequency of the longitudinal stretching vibration of the protrusions in this unit cell was calculated based on the calculation method described above, and the results are shown in Table 1.

[0099] Comparative Examples 1 and 2 are also unit cells including the sound-insulating sheet member shown in Fig. 16. The sizes, materials, and physical properties of the constituent members of the unit cell are shown in Table 1. The natural frequency of the longitudinal stretching vibration of the protrusions in this unit cell was calculated based on the calculation method described above, and the results are shown in Table 1.

[0100]

[0101] [Examples 1-2, Comparative Example 1] and [Examples 3-4, Comparative Example 2] have the same outer shape of the unit cell, and are a comparison of the presence or absence of portion iv. Despite the same protrusion dimensions, the natural frequency was 525 Hz in Example 1, 46 Hz in Example 3, and 699 Hz in Comparative Example 1, confirming that portion iv significantly lowered the natural frequency. Similarly, the natural frequency was 256 Hz in Example 3, 169 Hz in Example 4, and 355 Hz in Comparative Example 2, confirming that portion iv significantly lowered the natural frequency.

[0102] <Aspects without weight portion> [Examples 5 to 8] Examples 5 to 8 are unit cells including the sound-insulating sheet member shown in Fig. 17. The sizes, materials, and physical properties of the constituent members of the unit cells are shown in Table 2. The natural frequency of the longitudinal stretching vibration of the protrusions in this unit cell was calculated based on the calculation method described above, and the results are shown in Table 2.

[0103] Comparative Examples 3 and 4 are also unit cells including the sound-insulating sheet member shown in Fig. 17. The sizes, materials, and physical properties of the constituent members of the unit cells are shown in Table 2. The natural frequencies of the longitudinal stretching vibrations of the protrusions in this unit cell were calculated based on the above calculation method, and the results are shown in Table 2.

[0104] [Examples 5-6, Comparative Example 3] and [Examples 7-8, Comparative Example 4] each have the same outer shape of the unit cell, and are a comparison of the presence or absence of portion iv. Despite the same protrusion dimensions, the natural frequency was 811 Hz in Example 5, 621 Hz in Example 6, and 997 Hz in Comparative Example 3, confirming that portion iv significantly lowers the natural frequency. Similarly, the natural frequency was 404 Hz in Example 7, 314 Hz in Example 8, and 498 Hz in Comparative Example 4, confirming that portion iv significantly lowers the natural frequency.

[0105]

[0106] <Experiment 2> Silicone sound-insulating sheets were fabricated under the molding conditions of Examples 1' to 4' and Comparative Examples 1' to 2'. KE-941-U (manufactured by Shin-Etsu Silicone Co., Ltd.) was used as the silicone, and a nut (made of stainless steel) was used as the weight. A6-sized sound-insulating sheets for Examples 1' to 4' and Comparative Examples 1' to 2' were fabricated according to the convex dimensions shown in Table 1. Fabrication was carried out through the following steps (1) to (4): (1) preparing a mold with multiple cavities and placing weights in the multiple cavities formed in the mold; (2) pouring a resin material into the cavities; (3) curing the poured resin material (curing temperature: 165°C, heating time: 12 minutes); and (4) peeling the resulting cured product from the mold to obtain a sound-insulating sheet member. The Young's modulus of the fabricated silicone rubber was measured using a dynamic viscoelasticity analyzer DMS6100 and was 7.2 MPa at 25°C and 10 Hz.

[0107] (Examples 1' to 4', Comparative Examples 1' to 2') [Projection Vibration Experiment] A vibration experiment was conducted on the projections of the silicone sound-insulating sheet prepared above. First, one projection was cut out from the sound-insulating sheet, and the cut-out projection was adhered to a cylindrical base (dimensions: φ30 mm, thickness: 10 mm, material: A5250) using adhesive: D434-EL (manufactured by Toagosei Co., Ltd.) to prepare a measurement sample. The prepared measurement sample was vibrated using a small vibrator: K2007E01 (manufactured by The Modal Shop), and the force and velocity signals applied to the base were analyzed using an FFT analyzer: OR34 (manufactured by OROS). The vibration conditions were such that the base was subjected to a sweep vibration at 10 Hz to 1000 Hz using a sine signal, and the aforementioned force and velocity output signals were obtained. The analysis conditions were a frequency resolution of 1.25 Hz, and FFT was performed. The force was divided by the velocity to calculate the impedance (dB). The impedance of the measurement sample alone was obtained by subtracting the impedance measured with only the base from the impedance of the base and measurement sample. The measurement results are shown in Figures 18 and 19, and the frequency at which the impedance of the measurement sample was maximum is indicated in the figures.

[0108] 18 shows the measurement results for Examples 1' and 2' and Comparative Example 1', comparing the presence and absence of a space, with the same external shape. Despite the same protrusion dimensions, the frequency at which the impedance is maximized, i.e., the natural frequency, was 522 Hz for Example 1', 349 Hz for Example 2', and 693 Hz for Comparative Example 1', confirming that the natural frequency was lower, as in the simulation results.

[0109] Figure 19 shows the measurement results for Examples 3' to 4' and Comparative Example 2', comparing the presence and absence of a space, with the same external shape. Despite the same protrusion dimensions, the frequency at which the impedance is maximum, i.e., the natural frequency, was 258 Hz for Example 3', 174 Hz for Example 4', and 356 Hz for Comparative Example 2', confirming that the natural frequency was lowered, just as in the simulation results. From these results, it was possible to confirm that the natural frequency of the protrusions was lowered in the actual measurements, just as in the simulations.

[0110] <Experiment 3> <Study on trampoline vibration> Examples A-1 to A-6 and Comparative Examples B-1 to B-3 are unit cells including the sound-insulating sheet member shown in Fig. 16. The sizes, materials, and physical properties of the constituent members of the unit cells are shown in Tables 3 and 4. Table 4 shows the sizes, materials, and physical properties of the constituent members common to Examples A-1 to A-6 and Comparative Examples B-1 to B-3. The natural frequency (resonance frequency) of the longitudinal stretching vibration or trampoline vibration of the protrusions in this unit cell, and the Z component d of the displacement field of the outer periphery P of the tip of the convex portion 21 Ｐ and the Z component d of the displacement field at the center Q of the tip of the convex portion 21 Ｑ Ratio d to Ｐ / d Ｑ , were calculated using the above-mentioned COMSOL Multiphysics (manufactured by COMSOL), and the results are shown in Table 3. The conditions for the physical simulation will be described in detail below.

[0111] As in Experiment 1, the finite element method was used for this physical simulation. For each of the portions i to v of the sound insulation structure in Figure 16, the physical properties (specific gravity, storage modulus (Young's modulus), Poisson's ratio) listed in Table 4 and the material dimensions (r, h, a) listed in Tables 3, 4, and Figure 16 were substituted into the equations of the solid mechanics module of COMSOL Multiphysics (manufactured by COMSOL), and the natural vibration mode was calculated under the condition that the bottom surface of the sheet portion v was completely fixed. Note that Figure 16 shows an embodiment in which a perforated nut (hexagonal plate) was used as the weight portion. Since this calculation assumes an ideal state where there is no influence from the adhesive, the natural frequency was calculated under the condition that the bottom surface of the portion v was completely fixed.

[0112] In Table 3, "displacement field Z component ratio d Ｐ / d Ｑ " is the Z component d of the displacement field of the outer periphery P of the tip of the convex portion 21 Ｐ and the Z component d of the displacement field at the center Q of the tip of the convex portion 21 Ｑ It represents the ratio of Ｐ / d Ｑ The closer the value of d is to 1, the more the outer periphery P of the tip of the protrusion 21 and the center Q of the tip of the protrusion 21 vibrate to the same extent, that is, the stronger the properties of the longitudinal stretching vibration mode. Ｐ / d ＱThe closer the value of is to 0, the greater the movement of the center Q of the tip of the protrusion 21 relative to the outer periphery P of the tip of the protrusion 21, that is, the stronger the characteristics of the trampoline vibration mode.

[0113]

[0114]

[0115] Comparative Examples B-1 to B-3 show the configurations of Examples A-1 to A-4, A-5, and A-6, respectively, without the space portion iii and slit portion iv, and are used as reference for calculating the amount of frequency shift. In Examples A-1 to A-4, the radius of the convex portion, the height of the convex portion, and the space portion area ratio of the unit cell are the same, and the slit portion height h ｉｖ In Examples A-1 and A-2, which show the longitudinal stretching vibration mode, the natural frequencies are 757 Hz and 580 Hz, respectively, but in Examples A-3 and A-4, which show the trampoline vibration mode, the natural frequencies are 410 Hz and 316 Hz, respectively, and the slit height h ｉｖ It was confirmed that as the vibration intensity increases, the vibration mode shifts from the longitudinal vibration mode to the trampoline mode, and the natural frequency decreases. The trampoline vibration mode has a larger frequency shift rate of the natural frequency than the longitudinal extension vibration mode, and is therefore a mode more suitable for lowering the frequency.

[0116] A comparison between Example A-4 and Example A-5 shows that the slit height h is set so that the natural frequencies of the vertical stretching vibration and the trampoline vibration are almost equal. ｉｖ This is a comparison in which the height of the convex portion was adjusted. Although both have almost the same natural frequency, the height of the convex portion in Example A-5, which shows the longitudinal extension vibration mode, is 10.2 mm, and the height of the convex portion in Example A-4, which shows the trampoline vibration mode, is 4.5 mm, and it was confirmed that the height of the convex portion required to cause resonance at a specific natural frequency is lower in the trampoline vibration mode. From the above, it was confirmed that when designing the shape of the convex portion of the same frequency, the height of the convex portion can be made lower by using the trampoline vibration mode than in the longitudinal extension vibration mode.

[0117] 11: Sheet portion 11a: Sheet surface 11b: Sheet surface 12: Space portion 12r: Space portion (convex portion) 12s: Space portion (seat portion) 12t: Space portion (slit portion) 21: Convex portion 22: Convex forming portion 22': Tip side inner wall surface 23: Weight portion 23': Weight 24: Sound absorbing material 51: Support body 100: Sound insulating sheet member 101: Sound insulating sheet member 200: Sound insulating structure 201: Sound insulating structure S: Spring portion Q: Square portion

Claims

1. Having a protrusion that has rubber elasticity, The aforementioned protrusion has a space, The aforementioned protrusion is a sound-insulating member having a slit on the inner wall surface at the tip of the protrusion.

2. The sound-insulating member according to claim 1, wherein the slit portion is formed circumferentially on the inner wall on the tip side of the protrusion.

3. The aforementioned protrusion, at its natural frequency, has a displacement field Z component of the outer circumference of the tip of the protrusion that is d Ｐ , the Z component of the displacement field at the center of the tip of the convex portion is d Ｑ When that happens, d Ｐ / d Ｑ The sound-insulating member according to claim 1, having vibration modes that satisfy ≤0.

8.

4. The aforementioned protrusion has a weight portion on its inner wall at its tip, The sound-insulating member according to claim 1, wherein the slit portion is formed circumferentially around the weight portion.

5. The sound-insulating member according to claim 1, wherein the slit portion is formed circumferentially on the inner wall on the tip side of the protrusion.

6. The sound-insulating member according to Claim 1, wherein in the cross-section of the convex portion, the proportion of the area occupied by the space portion is 90% or less in the cross-section where the proportion is greatest.

7. The sound-insulating member according to Claim 1, wherein in the cross-section of the convex portion, the proportion of the area occupied by the space portion is 20% or more in the cross-section where the proportion is greatest.

8. The sound-insulating member according to claim 1, wherein the proportion of the volume occupied by the space in the protrusion is 10% or more.

9. The sound-insulating member according to claim 1, wherein a portion of the space of the protrusion is provided to reach at least one of the tip surface and side surface of the protrusion.

10. The equivalent diameter D of the weight portion is represented by the following formula. Ｗ The equivalent diameter D of the protrusion is expressed by the following formula. Ｐ The ratio (D Ｐ / D Ｗ The sound-insulating member according to claim 4, wherein the ratio is 1.20 or greater. D Ｐ =4A Ｐ / p Ｐ D Ｗ =4A Ｗ / p Ｗ D Ｐ : Equivalent diameter of the protrusion D Ｗ : Equivalent diameter of the weight A Ｐ : Area of ​​the region formed from the outer circumference of the cross-section of the protrusion in the transverse direction of the protrusion. A Ｗ : Area of ​​the region formed from the outer circumference of the cross-section of the convex portion in the transverse direction of the convex portion. p Ｐ : Length of the outer circumference of the cross-section of the protrusion in the transverse direction of the protrusion p Ｗ : The length of the outer circumference of the cross-section of the weight portion in the transverse direction of the convex portion.

11. The sound-insulating member according to claim 4, wherein at least a portion of the weight portion is embedded in the protrusion portion.

12. A sound-insulating member according to any one of claims 1 to 11, and a sheet portion having rubber elasticity, The aforementioned protrusion is a sound-insulating sheet member provided on at least one surface of the sheet portion.

13. The sound-insulating sheet member according to claim 12, wherein the sheet portion has a space, and the space of the sheet portion is provided so as to penetrate from the side of the sheet portion opposite to the side on which the protrusion is provided to the space of the protrusion.

14. D is represented by the following formula Ｐ The ratio of the sum of the height of the protrusion and the thickness of the sheet portion H to (H / D Ｐ The sound insulation sheet member according to claim 12, wherein the value of ) is 3.0 or less. D Ｐ =4A Ｐ / p Ｐ D Ｐ : Equivalent diameter of the protrusion A Ｐ : Area of ​​the region formed from the outer circumference of the cross-section of the protrusion in the transverse direction of the protrusion. p Ｐ : Length of the outer circumference of the cross-section of the protrusion in the transverse direction of the protrusion

15. The sound-insulating sheet member according to claim 12, which is a single-piece molded product.

16. A sound insulation structure comprising at least a sound insulation sheet member according to claim 12 and a support for supporting the member.

17. The sound-insulating structure according to claim 16, wherein the sheet portion and the protrusion portion independently contain at least one selected from the group consisting of thermosetting elastomers, photocurable elastomers, and thermoplastic elastomers.

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