JP2019089491A - Sound absorption structure - Google Patents

Abstract

To provide a sound absorption structure having excellent sound absorption performance though being thin and lightweight.SOLUTION: An attenuation layer 12 positioned at an interval in a fender 15 is composed of any of forms including a fiber layer containing heat-adhesive fiber, a polymer layer, and a complex of them. A large number of recessed parts 14, which communicate with an air layer S formed in a space with the fender 15 and film-vibrate at their bottoms, are provided on a side surface of the fender 15 of the attenuation layer 12, and a resonator is constituted of the recessed parts 14 of the attenuation layer 12 and the space S.SELECTED DRAWING: Figure 2

Description

  The present invention is, for example, fender liners, rear liners, dash silencers, floor carpets, floor mats, door trims, pillars, ceiling materials, interiors and exterior materials such as automobiles, railways and aircrafts such as luggage trims, or floorings and ceilings of houses. The present invention relates to a sound absorbing structure suitable as an interior material such as wood and wall materials. In particular, the present invention relates to a sound absorbing structure that is thin and light and yet has excellent sound absorption.

  In the past, for example, in applications of interior and exterior materials such as fender liners for automobiles, indoor noise has also been used as engine noise in the process of developing automobiles powered by motors such as hybrid cars, electric cars, and fuel cell cars in recent years. The wind noise, road noise and stone horns that were hidden in the close up, and it is desirable to take measures.

  Patent Document 1 proposes a sound absorbing structure in which a low density non-woven fabric and a high density fiber structure are laminated and integrated for the purpose of reducing road noise and stone humming noise.

Unexamined-Japanese-Patent No. 2004-145180

  In the case of the conventional sound absorbing structure, in order to secure sufficient performance, a certain thickness has been required. However, there are severe limitations on fender liners and other interior and exterior materials such as automobiles, railroads, and aircraft, and when applied to such applications, the sound absorption is reduced somewhat to make the thickness thinner, and the thickness limitations You need to clear it. For this reason, as a sound absorbing fiber to be applied to interior and exterior materials of automobiles, railways, aircrafts, and the like having a strict thickness limitation, a thin, lightweight and sufficiently sound absorbing material is required.

  The present invention has been made in view of such circumstances, and it is an object of the present invention to provide a sound absorbing structure having excellent sound absorbing performance despite being thin and lightweight.

  In order to achieve the above object, the invention according to claim 1 comprises a panel, a carpet, an exterior wall or an interior wall (hereinafter referred to as a panel or the like) comprising a damping layer spaced apart, and the panel of the damping layer The sound absorption structure is characterized in that the equal side is provided with a large number of concave portions which are in communication with the space between the panel and the like and the bottom portion vibrates in a film.

  The invention according to claim 2 is characterized in that the sound absorbing structure according to claim 1 is characterized in that the bottom of the recess is made of a thin portion or a film.

  The invention according to claim 3 is characterized in that the sound absorbing structure according to claim 1 or 2 is provided such that the recess has a smaller diameter in the thickness direction.

  The invention according to claim 4 is characterized in that the damping layer comprises any of a fiber layer containing heat-adhesive fibers, a polymer layer, and a composite thereof. The sound absorbing structure is the summary.

  The invention according to claim 5 is characterized in that the damping layer comprises p- (p-toluenesulfonylamide) diphenylamine, 4,4′-bis (α, α-dimethylbenzyl) diphenylamine, octylated diphenylamine, 2,2′-methylene bis (4-ethyl-6-tert-butylphenol), 4,4'-thiobis (3-methyl-6-tert-butylphenol), and selected from N, N'-di-2-naphthyl-p-phenylenediamine The sound absorbing structure according to claim 4, characterized in that it comprises an organic damping filler consisting of one or more compounds.

  The invention according to claim 6 is the gist of a fender liner characterized in that the sound absorbing structure according to any one of claims 1 to 5 is used.

  The invention according to claim 7 is a floor mat characterized in that the sound absorbing structure according to any one of claims 1 to 5 is used.

The invention according to claim 8 is a floor mat installed on a carpet, wherein
It consists of a skin layer and a backing layer,
The backing layer is provided with a number of non-slip projections which act as a support to form a space between the floor mat and the floor carpet when the floor mat is placed on the floor carpet, and a thin-walled membrane at the bottom. 8. The floor mat according to claim 7, characterized in that the floor mat is provided with a plurality of recesses and connected to a space between the floor mat and the furo carpet.

  In the invention according to claim 9, the outer periphery of the floor mat is edged with an overlocking yarn, and when the floor mat is installed on a carpet, the overlocking portion hits the carpet and the backing layer and the carpet The floor mat according to claim 8, characterized in that the space is sealed.

  In the sound absorbing structure of the present invention, the membrane vibrates when a sound strikes the bottom of the recess connected to the space between the panel and the like provided on the side surface of the panel of the damping layer, etc. And an air layer formed in a space between the panel and the like constitute a vibration system, and the noise reduction effect is achieved by the sound absorption effect.

  Further, in the sound absorbing structure of the present invention, a large number of recesses having a bottom portion that vibrates in a film when sound is applied are connected to an air layer formed in the space between the attenuation layer and the panel etc. A resonator is configured by air in a plurality of recesses provided on the side surfaces of the layer and the panel of the damping layer. For this reason, noises such as road noises, stone splashes, rains and wind noises are effectively reduced by the sound absorption effect by Helmholtz resonance.

  In the sound absorbing structure of the present invention, when a fiber layer to which a polymer containing an organic damping filler is attached or a polymer layer containing an organic damping filler is used as the damping layer, the organic damping included in the damping layer Fillers convert sound and vibration energy into heat and electricity energy to attenuate noise.

BRIEF DESCRIPTION OF THE DRAWINGS The perspective view which shows the fender liner to which this invention is applied. The principal part expanded sectional view when the fender liner of FIG. 1 is attached to a vehicle body. The disassembled perspective view which shows another form of the fender liner to which this invention is applied. The principal part expanded sectional view of the floor mat to which the present invention is applied. The principal part expansion schematic diagram of the recessed part shown in FIG. The enlarged schematic diagram which shows the engraving roll which forms a recessed part.

  Hereinafter, the present invention will be described in detail according to an example applied to a fender liner shown in the drawings. The liner 11 shown in FIGS. 1 and 2 comprises a damping layer 12 and is spaced from the fender 15.

  The damping layer may take the form of any of a fiber layer containing heat-adhesive fibers, a polymer layer and a composite thereof. When the form of a fiber layer is employed as the damping layer, examples of the fiber layer include woven fabric, knitted fabric, paper, non-woven fabric, film and composites thereof. The fiber material constituting the fiber layer is not particularly limited, and polyolefin fibers such as polypropylene and polyethylene, polyester fibers such as polyethylene terephthalate, polyamide fibers such as nylon 6 and nylon 66, acrylic fibers such as polyacrylonitrile, Or synthetic fibers such as polyvinyl alcohol fibers, regenerated fibers such as rayon fibers, semi-synthetic fibers such as acetate fibers, vegetable fibers such as cotton and hemp, and animal fibers such as wool fibers and feather fibers The above can be mentioned.

  Moreover, when the form of a fiber layer is taken as a damping layer, a thermoadhesive fiber is contained in a fiber layer. As the heat-adhesive fiber, a low melting fiber consisting of a resin component having a melting point of 140 ° C. or less or a composite fiber in which a low melting resin component and a high melting resin component are combined can be used. Specifically, for example, polyester-polypropylene, polypropylene-low melting point polypropylene, polypropylene-polyethylene, polyethylene vinyl acetate copolymer-polypropylene, polyester-low melting point polyester, polyamide-low melting point polyamide, polyester-polyamide, etc. can be mentioned. .

  The content of the heat-adhesive fiber in the fiber layer may be appropriately determined in consideration of the application and the state of use. Specifically, it is 20 to 100% by weight, preferably 40 to 80% by weight. If it is less than 20% by weight, the shape retention property is poor, the formation of the recess to be described later becomes difficult, and there is a possibility that the bottom portion of the recess where the film vibrates can not be formed.

  When taking the form of a polymer layer as the damping layer, examples of the polymer constituting the polymer layer include polyvinyl chloride, polyvinylidene chloride, methyl polyacrylate, methyl polymethacrylate, ethylene-vinyl acetate copolymer, polyethylene, polypropylene , Acrylonitrile-styrene copolymer, acrylonitrile-butadiene-styrene copolymer, polyamide, polyester, polycarbonate, polyacetal, fluorocarbon resin, unsaturated polyester, epoxy, phenol, melamine, urethane and silicone resin, styrene-butylene-styrene copolymer At least one or two or more selected from among combined (SBS) and styrene-ethylene-butylene-styrene copolymer (SEBS) are desirable.

  On the side surface of a fender 15 of the liner 11 shown in FIG. A vibration system is formed by the air layer S formed in the space between the film portion at the bottom of the concave portion 14 and the fender 15, and the noise absorption effect is made to reduce noise.

  In addition, the liner 11 is configured of a resonator by the air in the many concave portions 14 having the bottom portion that vibrates in a film when a sound strikes and the air layer S formed in the space between the fender 15 to which the concave portions 14 are connected. The Helmholtz resonance produces an excellent sound absorption effect, and noises such as road noise, stone splashes, rain and wind noise can be effectively reduced.

  The recess may be formed, for example, as shown in FIG. 6, after heating to a temperature slightly higher than or equal to the melting point of the heat-adhesive fibers contained in the fiber layer, or in the heated state, if the damping layer is a fiber layer. The fiber is formed by cold-pressing with an engraving roll having a large number of pins on the outer peripheral surface corresponding to the shape of the above and passing the coolant through the inside and a pressure roll (not shown) for pressing the same. It is possible to form a recess in the layer. At this time, the heat-adhesive fiber of the tip portion (corresponding to the bottom of the recess) of the pin of the engraving roll to be drilled is formed into a film by heat and pressure at the time of pressing, and the bottom of the film vibrating recess is formed. become.

  When taking the form of a polymer layer as the damping layer, as shown in FIG. 6, for example, the resin extruded from the extruder has a large number of pins corresponding to the shape of the recess on the outer peripheral surface, It is possible to form a damping layer having a large number of recesses by performing a hole forming process by cold pressing with a roll and a pressing roll (not shown) that presses the roll. At this time, by pressing so that the pins on the outer peripheral surface of the engraving roll do not penetrate, the tip portion (corresponding to the bottom of the recess) is thinned, and the bottom of the recess capable of vibrating the membrane is formed.

  The shape of the concave portion 14 is not particularly limited, such as conical, pyramidal, hemispherical, cylindrical, square prism, etc. However, in the point that one provided so as to have a small diameter in the thickness direction is likely to cause Holmhertz resonance. preferable. By changing the size of the recess 14 (the cross-sectional area of the recess), the frequency of the sound causing the Holtz Hertz resonance changes, so the size of the recess may be appropriately determined according to the frequency of the sound to be absorbed.

  The bottom of the recess 14 is formed of a thin portion or film as described above, and the membrane portion 17 vibrates when sound is applied to the bottom of the recess 14. In this case, the thicker the film thickness, the easier it is to catch low frequency sound, and the thinner the film thickness works for high frequency sound. Also, the type of sound to be absorbed changes depending on the degree of tension of the film. That is, the loosely stretched membrane absorbs low frequency sound, and the strongly stretched membrane captures high frequency sound and absorbs sound.

  The damping layer 12 can be composed of a fiber layer to which a polymer containing an organic damping filler is attached or a polymer layer blended with an organic damping filler. Specifically, a polymer such as a thermoplastic elastomer compounded with an organic damping filler or a water-based emulsion resin is applied or impregnated to a fiber layer for adhesion, or the polymer constituting the polymer layer is blended with an organic damping filler to be molded. Can be produced by

  The organic damping filler is a compound capable of converting sound, vibration, shock, electromagnetic waves, electricity and heat energy into heat or electricity energy and attenuating. Specifically, p- (p-toluenesulfonylamido) diphenylamine, 4,4'-bis (α, α-dimethylbenzyl) diphenylamine, octylated diphenylamine, 2,2'-methylenebis (4-ethyl-6-tert- Butyl phenol), 4,4′-thiobis (3-methyl-6-tert-butylphenol), and N, N′-di-2-naphthyl-p-phenylenediamine selected from one or more compounds It can be mentioned.

  In addition to compatibility with the above-mentioned organic damping filler, in the selection of the polymer, the handling property, the moldability, the availability, the temperature performance (heat resistance and cold resistance), and the weather resistance according to the application and the use form It is desirable to consider price, etc.

  The compounding amount of the organic damping filler to the polymer is preferably 1 to 200 parts by weight with respect to 100 parts by weight of the polymer. When the content of the organic damping filler is less than 1 part by weight, sufficient energy damping property can not be obtained, and when it is more than 200 parts by weight, the damping property exceeding the range can not be obtained and it is uneconomical It is because

  The polymer may further contain at least one of a phthalocyanine compound, an iodine compound and a metal ion in addition to the organic damping filler. These phthalocyanine compounds, iodine compounds and metal ions are more preferable because they exhibit multiple functions such as antibacterial, antiviral, deodorizing, and allergen reducing effects alone.

  In the above-mentioned polymers, substances such as mica flakes, glass pieces, glass fibers, carbon fibers, calcium carbonate, barite, precipitated barium sulfate, corrosion inhibitors, dyes, antioxidants, antistatic agents, stabilizers, wetting agents An agent etc. can be suitably added as needed.

  The liner 11 shown in FIG. 1 uses a damping layer 12 in which an emulsion resin containing an organic damping filler is attached to a fiber layer, and a surface layer (not shown) made of non-woven fabric is provided on the outer surface.

  In addition to the sound absorption effect by the film vibration of the bottom of the recess 14 and the back air layer S, and the sound absorption effect by the Helmholtz of the recess 14 and the air layer S, the damping layer 12 has a sound absorbing property, a damping property, The combination of performances such as vibration resistance, shock absorption, electromagnetic wave absorption, antistaticity and heat insulation can be used for applications where multiple performances are required simultaneously.

  Next, another embodiment in which the sound absorbing structure of the present invention shown in FIG. 3 is applied to a fender liner will be described. The liner 21 is attached to a fender (not shown) with a gap. This liner 21 uses a damping layer composed of two non-woven fabrics 22 having different basis weights and a film 24 sandwiched between the plurality of non-woven fabrics 22, and a large number of through holes 23 are formed in the two non-woven fabrics 22. These two non-woven fabrics 22 are laminated such that the plurality of through holes 23 overlap, so that the films 24 are exposed to the respective through holes 23.

  In this liner 21, the film 24 is exposed to a large number of through holes 23 provided in the two laminated non-woven fabrics 22, and the through holes 22 on the fender (not shown) side constitute a recess. The film 24 exposed in each through hole 22 constitutes the film portion of the bottom of the recess. Then, sound intrudes through the film 24 exposed to the through hole 22, and the air in the through hole 22 on the fender (not shown) side and the air layer formed in the gap between the fender function as a resonator, and the sound is generated by Helmholtz resonance. Attenuation is to be made. In addition, the film 24 exposed to a large number of through holes 23 vibrates as a result of sound collision, and the sound is attenuated by the action of the vibration system constituted by the film 24 and the air layer formed in the gap between the fenders (not shown). It is supposed to be done.

  Next, an embodiment in which the sound absorbing structure of the present invention shown in FIGS. 4 and 5 is applied to a floor mat will be described. The floor mat 31 shown in FIGS. 4 and 5 comprises a skin layer 33 and a backing layer 32.

  The surface layer 33 may have various forms such as Wilton carpet, tufted carpet, needle punched carpet, and tread. The surface layer 33 of the floor mat shown in FIG. 4 is a base fabric 33a made of non-woven fabric, paper, cloth, felt, or a composite thereof, in which pile yarns 33b are punched into a substantially U shape in a predetermined volume. is there. The skin layer may be made of only a base fabric into which pile yarns are not driven, like a needle punched carpet.

  The backing layer 32 constitutes the damping layer of the sound absorbing structure according to the present invention, and a large number of non-slip projections 35 are provided at predetermined intervals on the back surface side (the carpet 36 side). For this reason, when the floor mat 31 is installed on the carpet 36 as shown in FIG. 4, a large number of non-slip projections 35 act as a support to create a gap between the backing layer 32 and the carpet 36, thereby (Air layer S) is formed.

  Further, the backing layer 32 is provided with a large number of substantially conical concave portions 34 as shown in FIG. 5 alternately with the non-slip protrusions 35, and a thin film portion 37 is formed on the bottom portion thereof. There is. As shown in FIG. 6, the backing layer 32 includes a large number of pins corresponding to the shape of the recess 34 shown in FIGS. 4 and 5 and a large number of holes corresponding to the shape of the non-slip projections 35. The surface layer 33 is sandwiched with a molten resin (semi-gelled state) extruded from the die of the extruder between the engraving roll through and the pressing roll (not shown) for pressing the same, and cold pressing is performed. By laminating, it is possible to form a backing layer 32 provided with a large number of recesses 34 having a substantially conical cross section alternately with the non-slip projections 35 shown in FIG. 4. At this time, by pressing so that the pins of the engraving roll do not penetrate, the tip portion (corresponding to the bottom of the recess) is thinned, and the film portion 37 at the bottom of the recess 34 capable of membrane vibration is formed.

  In the floor mat 31, the pile portion 33b (porous material) of the skin layer 33 effectively absorbs the sound in the high frequency region. In addition, the sound passing through the skin layer 33 hits the recess 34 of the backing layer 32 so that the membrane portion 37 at the bottom vibrates and the space formed between the membrane portion 37 and the carpet 36 behind (air The layer S) constitutes a vibration system so as to effectively absorb the sound in the middle and low frequency regions. Furthermore, the recess 34 (the air inside) of the backing layer 32 and the space (air layer S) connected thereto constitute a resonator, so that the sound in the middle and low frequency regions is effectively absorbed by Helmholtz resonance. .

  Also, the outer periphery of this floor mat is edged with overlock yarn, and when the floor mat is installed on a carpet, the overlock portion hits the carpet, and the air layer S of the backing layer 32 and the carpet 36 As a result, the sound absorption effect by the above-mentioned membrane vibration and the sound absorption effect of the resonator can be further improved.

  In addition, the polymer constituting the backing layer 32 is blended with an organic damping filler, and the energy of sound is converted to the energy of heat or electricity and attenuated by the organic damping filler. In addition to the sound absorption effect by the pile portion 33b, the sound absorption effect by the film vibration of the concave portion 34 of the backing layer 32, and the sound absorption effect by Helmholtz resonance by the concave portion 34 and the air layer S, further effective noise reduction is realized. Can.

  The present invention is not limited to the above example. For example, when the sound absorbing structure of the present invention is applied to a fender liner, the fender of the liner 11 is used to ensure the air tightness of the air layer S on the back of the liner 11. It can be freely changed and implemented in the range described in the claim, such as providing the convex part which divides the air layer S on the 15 side.

  The sound absorbing structure of the present invention can be applied to, for example, roof panels, floor panels, floor panels, door panels, front panels, rear panels, bonnets and the like, and panel structures of automobiles, railways and aircrafts, and further floor mats, first carpets, sheets, door trims. In addition to interior materials such as instrument panels, exterior materials such as ceiling interior materials, floor interior materials, bumpers, fender liners, engine covers, interior materials such as ceilings and walls of houses, roofing roofs, exterior materials such as doors And the like.

11, 21 ··· Liner 12 · · · Attenuation layer 13 · · · surface layer 14 · · · recess 15 · · · fender S · · · air layer

Claims (9)

  It consists of a damping layer arranged at intervals on a panel, a carpet, an exterior wall or an interior wall (hereinafter referred to as a panel etc.), and the side surface of the damping layer communicates with the space between the panel etc. What is claimed is: 1. A sound absorbing structure comprising: a plurality of concave portions in which the membrane vibrates.   The sound absorbing structure according to claim 1, wherein the bottom of the recess is formed of a thin portion or a film.   The sound absorption structure according to claim 1 or 2, wherein the recess is provided to be smaller in diameter in the thickness direction.   The sound absorbing structure according to any one of claims 1 to 3, wherein the damping layer comprises any of a fiber layer containing a heat-adhesive fiber, a polymer layer and a composite thereof.   Decaying layers are p- (p-toluenesulfonylamido) diphenylamine, 4,4'-bis (α, α-dimethylbenzyl) diphenylamine, octylated diphenylamine, 2,2'-methylenebis (4-ethyl-6-tert- Butyl phenol), 4,4'-thiobis (3-methyl-6-tert-butylphenol), and one or more compounds selected from N, N'-di-2-naphthyl-p-phenylenediamine A sound absorbing structure according to claim 4, comprising an organic damping filler.   A fender liner characterized by using the sound absorbing structure according to any one of claims 1 to 5.   A floor mat comprising the sound absorbing structure according to any one of claims 1 to 5. A floor mat installed on a carpet,
It consists of a skin layer and a backing layer,
The backing layer is provided with a number of non-slip projections which act as a support to form a space between the floor mat and the floor carpet when the floor mat is placed on the floor carpet, and a thin-walled membrane at the bottom. 8. A floor mat according to claim 7, characterized in that it has a plurality of recesses and a number of recesses leading to the space between said floor carpet and said furo carpet.   The outer periphery of the floor mat is edged with an overlocking thread, and when the floor mat is placed on a carpet, the overlocking portion hits the carpet and the space between the backing layer and the carpet is sealed. The floor mat according to claim 8, characterized in that