JP2007145056A - Roof part structure of automobile - Google Patents

Roof part structure of automobile Download PDF

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JP2007145056A
JP2007145056A JP2005338533A JP2005338533A JP2007145056A JP 2007145056 A JP2007145056 A JP 2007145056A JP 2005338533 A JP2005338533 A JP 2005338533A JP 2005338533 A JP2005338533 A JP 2005338533A JP 2007145056 A JP2007145056 A JP 2007145056A
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absorbing material
sound
sound absorbing
roof
layer
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JP4561611B2 (en
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Chie Fukuhara
千絵 福原
Kenichi Yamamoto
研一 山本
Takanobu Kamura
孝信 加村
Naoko Yorozu
菜穂子 萬
Hidetoshi Yamamoto
秀俊 山本
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Mazda Motor Corp
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Mazda Motor Corp
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Abstract

<P>PROBLEM TO BE SOLVED: To provide a roof part structure of an automobile, capable of efficiently and rationally absorbing and reducing sound of various frequency covering a wide range from low frequency to high frequency generated at the roof part of the automobile. <P>SOLUTION: In the roof part 2 structure of the automobile arranged with fiber sound absorbing materials 21, 22 under a roof panel 11, the first sound absorbing material 21 having a fiber direction which is a direction intersecting a direction along a roof surface is arranged at a center part of the roof part 2, and a second sound absorbing material 22 having the fiber direction generally along the roof surface is arranged on a peripheral edge portion of the roof part 2. Bulkhead layers 31, 32 partitioning the sound absorbing materials 21, 22 and a cabin are provided under the first and second sound absorbing materials 21, 22. Of the bulkhead layers 31, 32, air permeability of the bulkhead layer 32 under the second sound absorbing material is made to be higher than that of the bulkhead layer 31 under the first sound absorbing material 21. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

本発明は自動車のルーフ部構造に関し、走行中の自動車の車室内の騒音をルーフ部に内装した吸音材で低減する技術分野に属する。   The present invention relates to a structure of a roof part of an automobile, and belongs to a technical field in which noise in a vehicle interior of a running automobile is reduced by a sound absorbing material provided in a roof part.

一般に、自動車の走行中は、エンジン音、こもり音、ギヤノイズ、ロードノイズ、風切音等に起因する様々な騒音が車室内に伝達される。この車室内の騒音をできるだけ低減して、車室の静粛性を高め、乗員の居住性を向上することは、自動車の商品性を改良する観点から極めて重要な課題である。例えば、特許文献１には、ルーフパネルに、フェルトやポリエチレンテレフタレート等でなる繊維質の吸音材と、空気の音圧を反射する反射板とを備えた構成の自動車のルーフ構造が開示されている。これによれば、反射板により空気の音圧の減衰が防がれ、その結果、吸音材を通過する空気の粒子速度を高速に維持することができて、車室内の騒音をルーフ部の吸音材で効率よく低減することが可能となる。
特開２００５−２４７２６７号公報 In general, during driving of an automobile, various noises due to engine noise, booming noise, gear noise, road noise, wind noise, and the like are transmitted into the passenger compartment. Reducing the noise in the passenger compartment as much as possible, increasing the quietness of the passenger compartment, and improving the comfort of passengers is an extremely important issue from the viewpoint of improving the commerciality of automobiles. For example, Patent Document 1 discloses an automobile roof structure having a structure in which a roof panel is provided with a fibrous sound absorbing material made of felt, polyethylene terephthalate, or the like, and a reflector that reflects the sound pressure of air. . According to this, attenuation of the sound pressure of the air is prevented by the reflector, and as a result, the particle velocity of the air passing through the sound absorbing material can be maintained at a high speed, and the noise in the vehicle interior is reduced by the sound absorption It becomes possible to reduce efficiently with a material.
JP 2005-247267 A

ところで、走行中における車室内の騒音といっても、１００Ｈｚほどの低周波数の音から、１０００Ｈｚを越える高周波数の音まで、広範囲に亘る様々な周波数の音が混在しているのが現状である。例えば、本発明の発明者等は、図１に示すように、自動車１の走行中は、ルーフ部２の中央部では、例えばルーフパネルやトップシーリング材の振動等に起因して、相対的に低い周波数の音が多く発生する一方、ルーフ部２の周縁部では、例えばドアやコーナー部の風切音等に起因して、相対的に高い周波数の音が多く発生する傾向にあることを見い出した。そして、このように、広範囲に亘る様々な周波数の騒音を効率よくかつ合理的に吸音・低減する技術の提案は今のところ見当たらないのである。   By the way, even if it is the noise in the passenger compartment during traveling, the sound of various frequencies ranging from a low frequency sound of about 100 Hz to a high frequency sound exceeding 1000 Hz is mixed. . For example, as shown in FIG. 1, the inventors of the present invention are relatively in the center portion of the roof portion 2 due to, for example, vibrations of a roof panel and a top sealing material while the vehicle 1 is running. While many low-frequency sounds are generated, it is found that a relatively high-frequency sound tends to be generated at the peripheral portion of the roof portion 2 due to, for example, wind noise at the doors and corners. It was. As described above, there is no proposal for a technique for efficiently and rationally absorbing and reducing noise having various frequencies over a wide range.

そこで、本発明は、自動車のルーフ部で発生する低周波数から高周波数までの広範囲に亘る様々な周波数の音を効率よく合理的に吸音・低減することが可能な自動車のルーフ部構造の提供を課題とする。   Accordingly, the present invention provides an automobile roof structure that can efficiently and rationally absorb and reduce sounds of various frequencies ranging from a low frequency to a high frequency generated in the automobile roof. Let it be an issue.

前記課題を解決するため、本願の請求項１に記載の発明は、ルーフパネルの下方に繊維質の吸音材が配設された自動車のルーフ部構造であって、ルーフ部中央部に吸音材の繊維方向がルーフ面に沿った方向に対して交差した方向である第１吸音材が配設され、ルーフ部周縁部に吸音材の繊維方向がルーフ面に略沿った方向である第２吸音材が配設され、これらの第１、第２吸音材の下方に該吸音材と車室とを仕切る隔壁層が設けられて、該隔壁層のうち第２吸音材の下方部分の通気性が第１吸音材の下方部分の通気性よりも高くされていることを特徴とする。   In order to solve the above problems, the invention according to claim 1 of the present application is a roof structure of an automobile in which a fibrous sound absorbing material is disposed below the roof panel, and the sound absorbing material is disposed at the center of the roof portion. A first sound-absorbing material in which the fiber direction intersects the direction along the roof surface is disposed, and a second sound-absorbing material in which the fiber direction of the sound-absorbing material is substantially along the roof surface at the periphery of the roof portion And a partition layer for partitioning the sound absorbing material and the passenger compartment is provided below the first and second sound absorbing materials, and the air permeability of the lower portion of the second sound absorbing material in the partition layer is the first. It is characterized by being higher than the air permeability of the lower part of one sound-absorbing material.

次に、請求項２に記載の発明は、前記請求項１に記載の自動車のルーフ部構造において、前記隔壁層のうち第１吸音材の下方部分の剛性が第２吸音材の下方部分の剛性よりも低くされていることを特徴とする。   Next, the invention according to claim 2 is the vehicle roof structure according to claim 1, wherein the rigidity of the lower part of the first sound absorbing material is the rigidity of the lower part of the second sound absorbing material in the partition wall layer. It is characterized by being lowered.

次に、請求項３に記載の発明は、前記請求項１又は２に記載の自動車のルーフ部構造において、前記第１吸音材は、面状の吸音材がルーフ面に略沿った方向に折り重ねられ、ルーフパネルと隔壁層との間に収容されたものであることを特徴とする。   Next, according to a third aspect of the present invention, in the roof structure of an automobile according to the first or second aspect, the first sound absorbing material is folded in a direction in which the planar sound absorbing material is substantially along the roof surface. It is characterized by being stacked and housed between the roof panel and the partition wall layer.

そして、請求項４に記載の発明は、前記請求項１から３のいずれかに記載の自動車のルーフ部構造において、前記隔壁層のうち第１吸音材の下方部分は、第２吸音材の下方部分の通気性よりも低い通気性のシート部材を含み、該シート部材がルーフ部周縁部まで延設され、第２吸音材の上方に敷設されていることを特徴とする。   According to a fourth aspect of the present invention, in the roof structure of an automobile according to any one of the first to third aspects, a lower portion of the first sound absorbing material is below the second sound absorbing material in the partition wall layer. An air-permeable sheet member lower than the air permeability of the portion is included, the sheet member extends to the periphery of the roof portion, and is laid above the second sound absorbing material.

まず、請求項１に記載の自動車のルーフ部構造によれば、後述する本発明の最良の実施形態において明らかになるように、相対的に低い周波数の音が多く発生するルーフ部中央部では、吸音材の繊維方向がルーフ面に沿った方向に対して交差した方向である第１吸音材を配設し、かつ、この第１吸音材の下方に存在する隔壁層の通気性を相対的に低くする（通気性の無い場合を含む）一方で、相対的に高い周波数の音が多く発生するルーフ部周縁部では、吸音材の繊維方向がルーフ面に略沿った方向である第２吸音材を配設し、かつ、この第２吸音材の下方に存在する隔壁層の通気性を第１吸音材の下方に存在する隔壁層の通気性よりも高くすることによって、自動車のルーフ部で発生する低周波数から高周波数までの広範囲に亘る様々な周波数の音を簡単な構成によって極めて効率よくかつ合理的に吸音・低減することが可能となる。   First, according to the roof portion structure of an automobile according to claim 1, as will be apparent in the best embodiment of the present invention described later, in the central portion of the roof portion where a lot of relatively low frequency sounds are generated, A first sound-absorbing material in which the fiber direction of the sound-absorbing material intersects the direction along the roof surface is disposed, and the air permeability of the partition layer existing below the first sound-absorbing material is relatively On the other hand, the second sound-absorbing material in which the fiber direction of the sound-absorbing material is substantially along the roof surface at the periphery of the roof portion where a lot of relatively high-frequency sound is generated. And the air permeability of the partition layer existing below the second sound absorbing material is higher than the air permeability of the partition layer existing below the first sound absorbing material. A wide range of frequencies from low to high frequencies And well very efficiently the sound of several with a simple configuration becomes reasonably possible to sound absorption and reduction.

次に、請求項２に記載の自動車のルーフ部構造によれば、第１吸音材の下方に存在する隔壁層の剛性を第２吸音材の下方に存在する隔壁層の剛性よりも低くすることによって、車室側から第１吸音材の下方の隔壁層に音が衝突したときに、該隔壁層の振動が促進され、該隔壁層の上方空間内での水平方向の粒子速度がさらに速くなって、なお一層、第１吸音材による吸音効果が向上することとなる。   Next, according to the roof part structure of an automobile according to claim 2, the rigidity of the partition layer existing below the first sound absorbing material is made lower than the rigidity of the partition layer existing below the second sound absorbing material. By this, when sound collides with the partition layer below the first sound absorbing material from the vehicle compartment side, the vibration of the partition layer is promoted, and the horizontal particle velocity in the space above the partition layer is further increased. In addition, the sound absorption effect by the first sound absorbing material is further improved.

次に、請求項３に記載の自動車のルーフ部構造によれば、面状の吸音材をルーフ面に略沿った方向に折り重ね、ルーフパネルと隔壁層との間に収容することによって、繊維方向がルーフ面に沿った方向に対して交差した方向である第１吸音材を、極めて簡便に作製することができ、第１吸音材の施工性・成形性が向上することとなる。   Next, according to the roof part structure of an automobile according to claim 3, the sheet-like sound absorbing material is folded in a direction substantially along the roof surface and accommodated between the roof panel and the partition wall layer. The first sound-absorbing material whose direction intersects the direction along the roof surface can be produced very simply, and the workability and formability of the first sound-absorbing material are improved.

そして、請求項４に記載の自動車のルーフ部構造によれば、第１吸音材の下方に存在する隔壁層を、第２吸音材の下方に存在する隔壁層の通気性よりも低い通気性のシート部材を含む構成とし、該シート部材をルーフ部中央部からルーフ部周縁部まで延設して、ルーフ部周縁部では第２吸音材の上方に敷設することにより、第２吸音材の下方の隔壁層の通気性を第１吸音材の下方の隔壁層の通気性よりも極めて簡便に高くすることができ、隔壁層の施工性が向上することとなる。加えて、前記シート部材が隔壁層の上方を一面に覆うことになって、例えば、ルーフ部の最上部分に存在するルーフパネルの内面から、チリやホコリが、通気性を有する隔壁層をすり抜けて車室内に落下してくるのを防ぐことができ、ルーフ部の防塵性が維持されることとなる。以下、発明の最良の実施形態を通して本発明をさらに詳しく説明する。   According to the roof part structure of an automobile according to claim 4, the partition layer existing below the first sound absorbing material is made to be less breathable than the partition layer existing below the second sound absorbing material. The seat member includes a seat member, and the seat member extends from the center of the roof portion to the periphery of the roof portion, and is laid above the second sound absorbing material at the periphery of the roof portion. The air permeability of the partition wall layer can be made extremely simply higher than the air permeability of the partition wall layer below the first sound absorbing material, and the workability of the partition wall layer is improved. In addition, the sheet member covers the entire surface of the partition layer. For example, dust and dust pass through the partition layer having air permeability from the inner surface of the roof panel present at the uppermost portion of the roof portion. It can prevent falling into the passenger compartment, and the dustproof property of the roof portion is maintained. Hereinafter, the present invention will be described in more detail through the best mode for carrying out the invention.

図１は、本実施形態に係る自動車１の平面図である。前述したように、自動車１の走行中は、そのルーフ部２において、中央部では、相対的に低い周波数の音が多く発生する傾向にあり、周縁部では、相対的に高い周波数の音が多く発生する傾向にある。そこで、本実施形態では、図２に示すように、自動車１の車幅方向において、ルーフ部２の中央部を低周波数音吸音部とし、繊維質の吸音材の繊維層の方向がルーフ面に沿った方向に対して交差した方向、つまり図例では略上下方向（Ｚ軸方向）である第１吸音材２１を配設する一方、ルーフ部２の左右側縁部（周縁部の一部）を高周波数音吸音部として、繊維質の吸音材の繊維層の方向がルーフ面に略沿った方向、つまり図例では略水平方向（ＸＹ面方向）である第２吸音材２２を配設している。また、これと同様に、図３に示すように、自動車１の前後方向において、ルーフ部２の中央部を低周波数音吸音部とし、繊維質の吸音材の繊維層の方向がルーフ面に沿った方向に対して交差した方向、つまり図例では略上下方向（Ｚ軸方向）である第１吸音材２１を配設する一方（図は第１吸音材２１の１つの繊維層を正対視している）、ルーフ部２の前後側縁部（周縁部の一部）を高周波数音吸音部として、繊維質の吸音材の繊維層の方向がルーフ面に略沿った方向、つまり図例では略水平方向（ＸＹ面方向）である第２吸音材２２を配設している。   FIG. 1 is a plan view of an automobile 1 according to the present embodiment. As described above, when the automobile 1 is running, in the roof portion 2, there is a tendency that many sounds with relatively low frequencies are generated in the center portion, and there are many sounds with relatively high frequencies in the peripheral portion. Tend to occur. Therefore, in the present embodiment, as shown in FIG. 2, in the vehicle width direction of the automobile 1, the center portion of the roof portion 2 is a low frequency sound absorbing portion, and the fiber layer direction of the fibrous sound absorbing material is the roof surface. The first sound-absorbing material 21 that is in a direction intersecting with the direction along the direction, that is, in the example shown in FIG. Is a high-frequency sound absorbing portion, and a second sound absorbing material 22 is disposed in which the direction of the fiber layer of the fibrous sound absorbing material is substantially along the roof surface, that is, the substantially horizontal direction (XY surface direction) in the illustrated example. ing. Similarly, as shown in FIG. 3, in the longitudinal direction of the automobile 1, the center portion of the roof portion 2 is a low frequency sound absorbing portion, and the fiber layer direction of the fibrous sound absorbing material is along the roof surface. The first sound-absorbing material 21 that is in a direction intersecting with the first direction, that is, substantially in the vertical direction (Z-axis direction) in the example shown in FIG. The front and rear side edges (a part of the peripheral edge) of the roof part 2 are high frequency sound absorbing parts, and the direction of the fiber layer of the fibrous sound absorbing material is substantially along the roof surface. Then, the second sound absorbing material 22 which is substantially horizontal (XY plane direction) is disposed.

ここで、第１、第２吸音材２１，２２としては、例えば、フェルト等の天然繊維や、ポリエチレンテレフタレート（ＰＥＴ）等の合成繊維等からなる、吸音機能を有する、従来一般に使用される、繊維質の吸音材が広く用いられ得る。   Here, as the first and second sound-absorbing materials 21 and 22, for example, natural fibers such as felt, synthetic fibers such as polyethylene terephthalate (PET), etc., which have a sound-absorbing function and are generally used conventionally. Quality sound absorbing materials can be widely used.

その場合に、図２、図３において、第１、第２吸音材２１，２２は、ルーフパネル１１の下方に配設されている。また、第１、第２吸音材２１，２２の下方には、水平方向に広がる発泡ウレタン１４の層と不織布１３の層とが設けられている。さらに、第１吸音材２１と発泡ウレタン１４の層との間には、１枚の樹脂シート１５が介設されており、この樹脂シート１５は、ルーフ部２の左右側縁部及び前後側縁部まで延びて上方に曲折し、第２吸音材２２とルーフパネル１１との間に介設されている。この結果、第１吸音材２１の下方においては、上から順に、樹脂シート１５、発泡ウレタン１４層及び不織布１３層が積み重ねられた積層体が、第１吸音材２１と車室とを仕切る隔壁層３１を構成し、第２吸音材２２の下方においては、上から順に、発泡ウレタン１４層及び不織布１３層が積み重ねられた積層体が、第２吸音材２１と車室とを仕切る隔壁層３２を構成している。   In that case, in FIGS. 2 and 3, the first and second sound absorbing materials 21 and 22 are disposed below the roof panel 11. Further, below the first and second sound absorbing materials 21, 22, a layer of urethane foam 14 and a layer of nonwoven fabric 13 that are spread in the horizontal direction are provided. Further, a single resin sheet 15 is interposed between the first sound absorbing material 21 and the urethane foam 14 layer, and the resin sheet 15 includes the left and right side edges and the front and rear side edges of the roof portion 2. It extends to the section and bends upward, and is interposed between the second sound absorbing material 22 and the roof panel 11. As a result, in the lower part of the first sound absorbing material 21, a laminate in which the resin sheet 15, the urethane foam 14 layer, and the nonwoven fabric 13 layer are stacked in order from the top is a partition layer that partitions the first sound absorbing material 21 and the vehicle interior. In the lower part of the second sound absorbing material 22, the laminated body in which the urethane foam 14 layer and the nonwoven fabric 13 layer are stacked in order from the top forms a partition layer 32 that partitions the second sound absorbing material 21 and the vehicle interior. It is composed.

その場合に、不織布１３及び発泡ウレタン１４は通気性に富むものであるが、樹脂シート１５は、例えば塩化ビニルやポリエチレン等でなり、通気性に欠ける（あるいは通気性が無い）ものである。したがって、この樹脂シート１５を含む、第１吸音材２１の下方の隔壁層は、全体として、非通気性層３１であり、この樹脂シート１５を含まない、第２吸音材２２の下方の隔壁層は、全体として、通気性層３２である。なお、図３には、ルーフ部２の補強のために車幅方向に延設された複数のルーフレイン１２…１２が示されている。次に、図２、図３のような自動車１のルーフ部２の構造を採用した理由を図面を参照しながら説明する。   In this case, the nonwoven fabric 13 and the urethane foam 14 are rich in air permeability, but the resin sheet 15 is made of, for example, vinyl chloride or polyethylene, and lacks air permeability (or lacks air permeability). Therefore, the partition layer below the first sound absorbing material 21 including the resin sheet 15 is a non-breathable layer 31 as a whole, and the partition layer below the second sound absorbing material 22 not including the resin sheet 15. Is a breathable layer 32 as a whole. 3 shows a plurality of roof rains 12... 12 extended in the vehicle width direction for reinforcing the roof portion 2. Next, the reason why the structure of the roof portion 2 of the automobile 1 as shown in FIGS. 2 and 3 is adopted will be described with reference to the drawings.

図４は、音の周波数と、音の低減効果代との関係を表すグラフである。ここで、タイプ１は、図５（ａ）に示すように、吸音材の繊維層の方向が音の進行方向に対して垂直となるように吸音材を配置した場合であり、タイプ２は、図５（ｂ）に示すように、吸音材の繊維層の方向が音の進行方向に対して平行となるように吸音材を配置した場合である。その結果、図４に示したように、周波数の如何に拘らず、タイプ１がタイプ２よりも吸音効果の高いことが分かった。これは、およそ次のような理由によると考えられる。一般に、音の波のうち腹の部分はエネルギーが高いから、音の波の腹の部分が吸音材に衝突すると吸音率が向上することが知られている。そして、この観点より、タイプ１では、音の波の全部分が吸音材にぶつかるので、音の波の腹の部分が必ず吸音材に衝突するのに対し、タイプ２では、音の波の一部分が吸音材の繊維層の間をすり抜けるため、音の波の腹の部分が吸音材に衝突しないことがあると推察される。この知見により、吸音効果を高めるには、吸音材の繊維層の方向が音の進行方向に対して交差するように吸音材を配置するのがよいことが分かった。   FIG. 4 is a graph showing the relationship between the sound frequency and the sound reduction effect allowance. Here, type 1 is a case where the sound absorbing material is arranged so that the direction of the fiber layer of the sound absorbing material is perpendicular to the traveling direction of the sound, as shown in FIG. As shown in FIG. 5B, the sound absorbing material is arranged so that the direction of the fiber layer of the sound absorbing material is parallel to the sound traveling direction. As a result, as shown in FIG. 4, it was found that Type 1 has a higher sound absorption effect than Type 2 regardless of the frequency. This is probably due to the following reasons. In general, it is known that, since the antinode portion of the sound wave has high energy, the sound absorption rate is improved when the antinode portion of the sound wave collides with the sound absorbing material. From this point of view, in Type 1, the entire sound wave part hits the sound absorbing material, so that the antinode part of the sound wave always collides with the sound absorbing material, whereas in Type 2, part of the sound wave Since it passes through between the fiber layers of the sound absorbing material, it is presumed that the antinodes of the sound wave may not collide with the sound absorbing material. From this knowledge, it was found that the sound absorbing material should be arranged so that the direction of the fiber layer of the sound absorbing material intersects the sound traveling direction in order to enhance the sound absorbing effect.

図６は、トップシーリング材４１とルーフパネル１１との間の空間に吸音材を配設した場合における、トップシーリング材４１の種類と、音の低減効果代及び空気の粒子速度との関係を調べるための自動車１のレイアウト図である。自動車１は３列シートのミニバンを使用した。各列のシートのシートバックの上部に集音マイクを取り付けて音量観測点とした（四角記号）。また、車室の天井を構成するトップシーリング材４１の上方に各列のシートに対応させてセンサを配置して粒子速度観測点とした（黒丸記号）。その結果、図７に示すように、通気性の無いトップシーリング材４１を用いたときは、通気性の有るトップシーリング材４１を用いたときよりも、音の低減効果及び粒子速度ともに大きいことが分かった。ここで、音低減効果代は、３つの音量観測点の合計値であり、また粒子速度は、３つの粒子速度観測点における水平方向の粒子速度と上下方向の粒子速度との和の合計値である。   FIG. 6 shows the relationship between the type of the top sealing material 41, the sound reduction effect allowance, and the air particle velocity when the sound absorbing material is disposed in the space between the top sealing material 41 and the roof panel 11. 1 is a layout diagram of an automobile 1 for The automobile 1 used a three-row seat minivan. A sound collecting microphone was attached to the upper part of the seat back of each row of seats to provide a volume observation point (square symbol). In addition, sensors were arranged above the top sealing material 41 constituting the ceiling of the passenger compartment so as to correspond to the sheets in each row, and used as particle velocity observation points (black circle symbols). As a result, as shown in FIG. 7, when the non-breathable top sealing material 41 is used, both the sound reduction effect and the particle velocity are larger than when the breathable top sealing material 41 is used. I understood. Here, the sound reduction effect allowance is the total value of the three sound volume observation points, and the particle velocity is the sum of the sum of the horizontal particle velocity and the vertical particle velocity at the three particle velocity observation points. is there.

図７の実験結果は、およそ次のような理由によると考えられる。まず、トップシーリング材４１が非通気性であると、車室内の音波がトップシーリング材４１に衝突したときには、空気の粒子がトップシーリング材４１を通過せずにトップシーリング材４１を振動させる。そして、このトップシーリング材４１の振動により、トップシーリング材４１の上方空間、つまりトップシーリング材４１とルーフパネル１１との間の空間にある空気の粒子速度が増大するものと推察される。また、一般に、空気の粒子速度が高いほど吸音材による吸音効果が向上することが知られている。したがって、トップシーリング材４１が通気性を有していないときは、トップシーリング材４１が通気性を有しているときよりも、トップシーリング材４１とルーフパネル１１との間に配設した吸音材にぶつかる粒子速度が増大し、吸音効果が高まるものと考えられる。   The experimental result of FIG. 7 is considered to be due to the following reason. First, when the top sealing material 41 is non-breathable, when a sound wave in the vehicle interior collides with the top sealing material 41, air particles do not pass through the top sealing material 41 and vibrate the top sealing material 41. The vibration of the top sealing material 41 is presumed to increase the particle velocity of air in the space above the top sealing material 41, that is, the space between the top sealing material 41 and the roof panel 11. In general, it is known that the higher the particle velocity of air, the better the sound absorbing effect of the sound absorbing material. Accordingly, when the top sealing material 41 does not have air permeability, the sound absorbing material disposed between the top sealing material 41 and the roof panel 11 is more than when the top sealing material 41 has air permeability. It is considered that the particle velocity hitting the particle increases and the sound absorption effect increases.

さらに、本発明の発明者等は、トップシーリング材４１の種類と、トップシーリング材４１の上方空間内の空気の粒子速度との関係をより詳しく検討した。結果を図８〜図１１に示す。図８から明らかなように、非通気性のトップシーリング材４１が有るとき、換言すれば、車室内の空気の粒子がトップシーリング材４１を通過せず振動させる状態のときは、トップシーリング材４１が無いとき、換言すれば、トップシーリング材４１が振動する状態に無いときに比べて、特に符号アで示したように周波数が相対的に低い領域において、水平方向の粒子速度が増大することが分かった。また、図９から明らかなように、トップシーリング材４１が非通気性のときは、トップシーリング材４１が通気性のときよりも、特に符号イで示したようにやはり周波数が相対的に低い領域において、同様に水平方向の粒子速度が増大することが分かった。これらの知見から、相対的に低周波数の音をトップシーリング材４１の上方で吸音材を用いて効率よく吸音するには、非通気性のトップシーリング材（通気性の無いトップシーリング材や通気性の相対的に低いトップシーリング材を含む）４１を備えるとよいことが分かった。そして、この場合、水平方向の粒子速度が増大するのであるから、前述の図４、図５の知見に基き、吸音材の繊維層の方向が水平方向に対して交差するように、すなわち、吸音材の繊維層の方向が略上下方向に沿うように吸音材を配置すればよいことになる。   Furthermore, the inventors of the present invention examined the relationship between the type of the top sealing material 41 and the particle velocity of air in the space above the top sealing material 41 in more detail. The results are shown in FIGS. As is apparent from FIG. 8, when there is a non-breathable top sealing material 41, in other words, when air particles in the vehicle compartment vibrate without passing through the top sealing material 41, the top sealing material 41 is used. In other words, in other words, compared with the case where the top sealing material 41 is not in a vibrating state, the particle velocity in the horizontal direction is increased particularly in the region where the frequency is relatively low, as indicated by reference numeral a. I understood. Further, as apparent from FIG. 9, when the top sealing material 41 is non-breathable, it is a region where the frequency is also relatively low, as indicated by the symbol a, especially when the top sealing material 41 is breathable. It was found that the particle velocity in the horizontal direction increased as well. From these findings, in order to efficiently absorb relatively low frequency sound using the sound absorbing material above the top sealing material 41, a non-breathable top sealing material (a top sealing material having no air permeability or a breathable property). (Including a relatively low top sealant) 41. In this case, since the particle velocity in the horizontal direction is increased, the direction of the fiber layer of the sound absorbing material intersects the horizontal direction on the basis of the knowledge shown in FIGS. The sound absorbing material may be arranged so that the direction of the fiber layer of the material is substantially along the vertical direction.

これとは逆に、図１０から明らかなように、トップシーリング材４１が無いときは、非通気性のトップシーリング材４１が有るときに比べて、特に符号ウで示したように周波数が相対的に高い領域において、上下方向の粒子速度が増大することが分かった。また、図１１から明らかなように、トップシーリング材４１が通気性のときは、トップシーリング材４１が非通気性のときよりも、特に符号エで示したようにやはり周波数が相対的に高い領域において、同様に上下方向の粒子速度が増大することが分かった。これらの知見から、相対的に高周波数の音をトップシーリング材４１の上方で吸音材を用いて効率よく吸音するには、通気性のトップシーリング材（通気性の相対的に高いトップシーリング材を含む）４１を備えるとよいことが分かった。そして、この場合、上下方向の粒子速度が増大するのであるから、前述の図４、図５の知見に基き、吸音材の繊維層の方向が上下方向に対して交差するように、すなわち、吸音材の繊維層の方向が略水平方向に沿うように吸音材を配置すればよいことになる。   On the contrary, as is clear from FIG. 10, when the top sealing material 41 is not provided, the frequency is relatively higher than that when the non-breathable top sealing material 41 is provided, particularly as indicated by the symbol C. It was found that the particle velocity in the vertical direction increased in a very high region. Further, as apparent from FIG. 11, when the top sealing material 41 is air permeable, it is a region where the frequency is relatively high, as indicated by reference numeral D, particularly when the top sealing material 41 is non-air permeable. It was also found that the particle velocity in the vertical direction increased in the same manner. From these findings, in order to efficiently absorb a relatively high frequency sound using the sound absorbing material above the top sealing material 41, a breathable top sealing material (a top sealing material having a relatively high breathability is used). It was found to be good to include 41). In this case, since the particle velocity in the vertical direction increases, the direction of the fiber layer of the sound absorbing material intersects with the vertical direction based on the knowledge of FIG. 4 and FIG. The sound absorbing material may be arranged so that the direction of the fiber layer of the material is substantially in the horizontal direction.

以上のことから、相対的に低周波数の音が専ら発生する傾向にあるルーフ部２の中央部においては、前記図２、図３に示したように、低周波数の音を効率よく低減することを目的として、隔壁層（樹脂シート１５と発泡ウレタン１４層と不織布１３層とが積み重ねられた積層体）３１を非通気性（通気性の無い場合や通気性の相対的に低い場合を含む）とし、かつ、吸音材の繊維層の方向が略上下方向（Ｚ軸方向）に沿う構成の第１吸音材２１を配設するようにしたわけである。また、相対的に高周波数の音が専ら発生する傾向にあるルーフ部２の周縁部においては、前記図２、図３に示したように、高周波数の音を効率よく低減することを目的として、隔壁層（発泡ウレタン１４層と不織布１３層とが積み重ねられた積層体）３２を通気性（通気性の相対的に高い場合を含む）とし、かつ、吸音材の繊維層の方向が略水平方向（ＸＹ面方向）に沿う構成の第２吸音材２２を配設するようにしたわけである（以上、請求項１の構成に相当）。   From the above, in the central portion of the roof portion 2 where the relatively low frequency sound tends to be generated exclusively, the low frequency sound can be efficiently reduced as shown in FIGS. For the purpose, the partition wall layer (a laminate in which the resin sheet 15, the foamed urethane layer 14 and the nonwoven fabric 13 layer are stacked) 31 is non-breathable (including a case where there is no breathability or a case where the breathability is relatively low). In addition, the first sound absorbing material 21 having a configuration in which the direction of the fiber layer of the sound absorbing material is substantially along the vertical direction (Z-axis direction) is disposed. Moreover, in the peripheral part of the roof part 2 which tends to generate relatively high frequency sound, as shown in FIGS. 2 and 3, the purpose is to efficiently reduce high frequency sound. The partition wall layer (a laminated body in which the urethane foam 14 layer and the nonwoven fabric 13 layer are stacked) 32 is made to be air permeable (including the case where the air permeability is relatively high), and the direction of the fiber layer of the sound absorbing material is substantially horizontal. The second sound absorbing material 22 having a configuration along the direction (the XY plane direction) is disposed (corresponding to the configuration of claim 1 above).

この結果、図１２に拡大して例示するように、波長λが相対的に長く、周波数が相対的に低い音波（ｉ）が、樹脂シート１５と発泡ウレタン１４層と不織布１３層とからなる非通気性層３１に車室側から衝突したときには、空気の粒子が該非通気性層３１を通過せずに非通気性層３１を振動させ、非通気性層３１の上方空間内において水平方向の粒子速度が増大する。しかも、その粒子の進行方向である水平方向に対して第１吸音材２１の繊維層が略上下方向に広がっているので、音の波の全部分が第１吸音材２１にぶつかり、音の波の腹の部分が必ず第１吸音材２１に衝突することとなって、結果的に、前記低周波数の音（ｉ）の吸音率が向上する。   As a result, as illustrated in an enlarged manner in FIG. 12, the sound wave (i) having a relatively long wavelength λ and a relatively low frequency is formed of the resin sheet 15, the urethane foam 14 layer, and the nonwoven fabric 13 layer. When the air-permeable layer 31 collides from the passenger compartment side, air particles do not pass through the air-impermeable layer 31 and vibrate the air-impermeable layer 31, and particles in the horizontal direction in the space above the air-permeable layer 31. Increases speed. In addition, since the fiber layer of the first sound absorbing material 21 spreads in a substantially vertical direction with respect to the horizontal direction that is the traveling direction of the particles, the entire sound wave collides with the first sound absorbing material 21 and the sound wave. As a result, the sound absorption coefficient of the low frequency sound (i) is improved.

また、図１３に拡大して例示するように、波長λが相対的に短く、周波数が相対的に高い音波（ｉｉ）が、発泡ウレタン１４層と不織布１３層とからなる通気性層３２に車室側から衝突したときには、空気の粒子が該通気性層３２を通過して、通気性層３２の上方空間内において上下方向の粒子速度が増大する。しかも、その粒子の進行方向である上下方向に対して第２吸音材２２の繊維層が略水平方向に広がっているので、音の波（ｉｉ）の全部分が第２吸音材２２にぶつかり、音の波（ｉｉ）の腹の部分が必ず第２吸音材２２に衝突することとなって、結果的に、前記高周波数の音（ｉｉ）の吸音率が向上する。   Further, as illustrated in an enlarged manner in FIG. 13, a sound wave (ii) having a relatively short wavelength λ and a relatively high frequency is applied to the air-permeable layer 32 composed of the urethane foam 14 layer and the nonwoven fabric 13 layer. When colliding from the chamber side, air particles pass through the air-permeable layer 32, and the particle velocity in the vertical direction increases in the space above the air-permeable layer 32. And since the fiber layer of the 2nd sound absorption material 22 has spread in the substantially horizontal direction with respect to the up-down direction which is the advancing direction of the particle | grains, all the parts of the sound wave (ii) collide with the 2nd sound absorption material 22, The antinode portion of the sound wave (ii) always collides with the second sound absorbing material 22, and as a result, the sound absorption rate of the high frequency sound (ii) is improved.

このように、本実施形態においては、相対的に低い周波数の音が多く発生する傾向のルーフ部２の中央部では、吸音材の繊維方向がルーフ面に沿った方向に対して交差した方向である第１吸音材２１を配設し、かつ、この第１吸音材２１の下方に存在する隔壁層３１の通気性を相対的に低くする（通気性の無い場合を含む）一方で、相対的に高い周波数の音が多く発生する傾向のルーフ部２の周縁部では、吸音材の繊維方向がルーフ面に略沿った方向である第２吸音材２２を配設し、かつ、この第２吸音材２２の下方に存在する隔壁層３２の通気性を第１吸音材２１の下方に存在する隔壁層３１の通気性よりも高くすることによって、自動車１のルーフ部２で発生する低周波数から高周波数までの広範囲に亘る様々な周波数の音を簡単な構成によって極めて効率よくかつ合理的に吸音・低減することが可能となる。   Thus, in the present embodiment, in the central portion of the roof portion 2 that tends to generate a lot of relatively low-frequency sounds, the fiber direction of the sound absorbing material intersects the direction along the roof surface. A certain first sound absorbing material 21 is disposed, and the air permeability of the partition wall layer 31 existing below the first sound absorbing material 21 is relatively lowered (including the case where there is no air permeability), while the relative In the peripheral portion of the roof portion 2 that tends to generate a lot of high-frequency sound, a second sound absorbing material 22 in which the fiber direction of the sound absorbing material is substantially along the roof surface is disposed, and the second sound absorbing material is provided. By making the air permeability of the partition wall layer 32 existing below the material 22 higher than the air permeability of the partition wall layer 31 existing below the first sound absorbing material 21, the low frequency generated from the roof portion 2 of the automobile 1 is increased. Simple composition of sound of various frequencies over a wide range up to frequency Therefore and very efficiently it is reasonably possible to sound absorption and reduction.

ここで、第２吸音材２２の厚みと音の周波数との関係を考察する。図１４は、音の周波数と、音が吸音材へ垂直入射したときの吸音率との関係を表すグラフである。吸音材として厚みが２４ｍｍのものを用いた。その結果、周波数が高くなるほど吸音率が向上することが分かったが、この場合、特に、周波数が１６００Ｈｚと２０００Ｈｚとの間で最も吸音率の差が大きかったので、ここに着目した。すなわち、図示したように、音速を３４０ｍ／秒とすると、１６００Ｈｚの音の波長λは２１２ｍｍであり、その８分の１波長λは２７ｍｍとなって、これは吸音材の厚み２４ｍｍよりも大きい（図１３の音波（ｉｖ）参照）。一方、２０００Ｈｚの音の波長λは１７０ｍｍであり、その８分の１波長λは２１ｍｍとなって、これは吸音材の厚み２４ｍｍよりも小さい（図１３の音波（ｉｉｉ）参照）。したがって、８分の１波長λが吸音材の厚みよりも小さい音波（ｉｉｉ）は吸音率が良好となり、８分の１波長λが吸音材の厚みよりも大きい音波（ｉｖ）は吸音率が低調となると考えられる。このことに留意し、ルーフ部２に発生する音の周波数分布と、使用する第２吸音材２２の厚みとに応じて、第１吸音材２１の配設範囲及び第２吸音材２２の配設範囲をそれぞれ決定することが好ましい。   Here, the relationship between the thickness of the second sound absorbing material 22 and the frequency of sound will be considered. FIG. 14 is a graph showing the relationship between the frequency of sound and the sound absorption rate when the sound is perpendicularly incident on the sound absorbing material. A sound absorbing material having a thickness of 24 mm was used. As a result, it was found that the higher the frequency, the better the sound absorption rate. In this case, the difference in the sound absorption rate was particularly large between 1600 Hz and 2000 Hz. That is, as shown in the figure, when the sound speed is 340 m / sec, the wavelength λ of the sound of 1600 Hz is 212 mm, and the eighth wavelength λ is 27 mm, which is larger than the thickness of the sound absorbing material 24 mm ( Sound wave (iv) in FIG. 13). On the other hand, the wavelength λ of the sound of 2000 Hz is 170 mm, and the eighth wavelength λ thereof is 21 mm, which is smaller than the thickness of the sound absorbing material 24 mm (see sound wave (iii) in FIG. 13). Therefore, a sound wave (iii) having an eighth wavelength λ smaller than the thickness of the sound absorbing material has a good sound absorption rate, and a sound wave (iv) having an eighth wavelength λ larger than the thickness of the sound absorbing material has a low sound absorption rate. It is thought that it becomes. With this in mind, the arrangement range of the first sound absorbing material 21 and the arrangement of the second sound absorbing material 22 according to the frequency distribution of the sound generated in the roof portion 2 and the thickness of the second sound absorbing material 22 to be used. Preferably each range is determined.

また、図２、図３に明示したように、本実施形態においては、第１吸音材２１の下方の発泡ウレタン１４層の厚みを相対的に薄くし、第２吸音材２２の下方の発泡ウレタン１４層の厚みを相対的に厚くしている。つまり、第１吸音材２１の下方の隔壁層（非通気性層３１）の剛性を、第２吸音材２２の下方の隔壁層（通気性層３２）の剛性よりも、低く設定しているのである（以上、請求項２の構成に相当）。これにより、車室側から非通気性層３１に音が衝突したときに（図１２参照）、該非通気性層３１の振動が促進され、該非通気性層３１の上方空間内での水平方向の粒子速度がさらに速くなって、なお一層、第１吸音材２１の吸音性能の向上が図られることとなる。   2 and 3, in this embodiment, the thickness of the urethane foam layer 14 below the first sound absorbing material 21 is relatively reduced, and the urethane foam below the second sound absorbing material 22 is used. The 14 layers are relatively thick. That is, the rigidity of the partition layer (non-breathable layer 31) below the first sound absorbing material 21 is set lower than the rigidity of the partition layer (breathable layer 32) below the second sound absorbing material 22. There is (corresponding to the configuration of claim 2 above). Thereby, when a sound collides with the non-breathable layer 31 from the passenger compartment side (see FIG. 12), the vibration of the non-breathable layer 31 is promoted, and the horizontal direction in the space above the non-breathable layer 31 is accelerated. The particle speed is further increased, and the sound absorbing performance of the first sound absorbing material 21 is further improved.

また、図１２に明示したように、本実施形態においては、第１吸音材２１は、１枚の面状の吸音材をジグザグに蛇行させて折り重ね、その折り重ね方向をルーフ面に略沿った方向（図例では略水平方向）として、該吸音材をルーフパネル１１と非通気性層３１との間の空間内に収容・充填したものである（以上、請求項３の構成に相当）。これにより、繊維層の方向が略上下方向に沿う構成の第１吸音材２１を、極めて簡便に作製することができ、第１吸音材２１の施工性・成形性の向上が図られる。もちろん、これに限らず、複数枚の面状の吸音材をルーフパネル１１と非通気性層３１との間の空間内に順次縦に並べて収容・充填するようにしてもよい。   Further, as clearly shown in FIG. 12, in the present embodiment, the first sound absorbing material 21 is folded by zigzagging one sheet-like sound absorbing material, and the folding direction is substantially along the roof surface. The sound absorbing material is accommodated and filled in the space between the roof panel 11 and the non-breathable layer 31 as the direction (substantially horizontal direction in the figure) (this corresponds to the configuration of claim 3 above). . Thereby, the 1st sound-absorbing material 21 of the structure where the direction of a fiber layer follows a substantially up-down direction can be produced very simply, and the improvement of the workability and moldability of the 1st sound-absorbing material 21 is achieved. Of course, the present invention is not limited to this, and a plurality of planar sound absorbing materials may be accommodated and filled in the space between the roof panel 11 and the air-impermeable layer 31 one after another.

そして、図２、図３に明示したように、本実施形態においては、通気性の無いあるいは通気性の相対的に低い１枚の樹脂シート１５を、ルーフ部２の中央部では、第１吸音材２１の下面に敷設し、ルーフ部２の周縁部では、第２吸音材２２の上面に敷設している。その場合に、樹脂シート１５は、前述したように、ルーフ部２の中央部からルーフ部２の左右側縁部及び前後側縁部まで途切れることなく延びて、結果的に、不織布１３層及び発泡ウレタン１４層を上方から一面に被覆している（以上、請求項４の構成に相当）。これにより、極めて簡便に、第２吸音材２２の下方の隔壁層３２の通気性を第１吸音材２１の下方の隔壁層３１の通気性よりも高くすることができ、隔壁層３１，３２の施工性が向上することとなる。例えば、不織布１３、発泡ウレタン１４、周縁部の第２吸音材２２、樹脂シート１５、中央部の第１吸音材２１、及びルーフパネル１１を、この順に上に重ねていけば、本実施形態のルーフ部２が容易に得られる。   As shown in FIGS. 2 and 3, in the present embodiment, one resin sheet 15 having no air permeability or relatively low air permeability is disposed at the central portion of the roof portion 2 with the first sound absorption. It is laid on the lower surface of the material 21, and is laid on the upper surface of the second sound absorbing material 22 at the peripheral edge of the roof portion 2. In this case, as described above, the resin sheet 15 extends without interruption from the center portion of the roof portion 2 to the left and right side edges and the front and rear side edges of the roof portion 2, and as a result, the nonwoven fabric 13 layer and foam The urethane 14 layer is coated on the entire surface from above (corresponding to the structure of claim 4 above). Thereby, the air permeability of the partition wall layer 32 below the second sound absorbing material 22 can be made extremely simpler than the air permeability of the partition wall layer 31 below the first sound absorbing material 21. Workability will be improved. For example, if the nonwoven fabric 13, the urethane foam 14, the peripheral second sound absorbing material 22, the resin sheet 15, the central first sound absorbing material 21, and the roof panel 11 are stacked in this order, The roof part 2 is easily obtained.

加えて、樹脂シート１５が不織布１３層及び発泡ウレタン１４層の上方を一面に覆うことにより、例えば、ルーフ部２の最上部分に存在するルーフパネル１１の内面から、チリやホコリが、通気性に富む不織布１３層及び発泡ウレタン１４層をすり抜けて車室内に落下してくるのを防ぐことができ、トップシーリング材４１ないしルーフ部２の防塵性が維持されることとなる。   In addition, the resin sheet 15 covers the upper surface of the nonwoven fabric 13 layer and the foamed urethane 14 layer over the entire surface, so that, for example, dust and dust from the inner surface of the roof panel 11 existing at the uppermost portion of the roof portion 2 are made breathable. It is possible to prevent the nonwoven fabric 13 layer and the urethane foam 14 layer from slipping through and falling into the vehicle interior, and the dustproof property of the top sealing material 41 or the roof portion 2 is maintained.

なお、前記実施形態は、本発明の最良の実施形態ではあるが、特許請求の範囲を逸脱しない限り、なお種々の修正、変更が可能なことはいうまでもない。例えば、前記実施形態では、図２、図３において、第１吸音材２１の繊維層の重なり方向は車幅方向であったが、これに代えて、前後方向であってもよく、また、車幅方向と前後方向とを組み合わせてもよい。さらに、吸音材２１，２２と車室とを仕切る隔壁層３１，３２を構成する通気性の要素１３，１４及び非通気性の要素１５は、通気性又は非通気性でありさえすれば、他の素材で構成されたものであっても一向に構わない。さらに、前記実施形態では、車室の天井一面に不織布１３層と発泡ウレタン１４層と積層し、吸音材２１，２２の下方に樹脂シート１５が有るか無いかにより非通気性層３１と通気性層３２とを形成するようにしたが、もともと通気性の異なる隔壁層をルーフ部２中央部とルーフ部２周縁部とに区分して配設することも可能である。さらに、前記実施形態では、ルーフ部２の前後左右の全周を高周波数音吸音部とし、ルーフ部２の前後左右の全周に亘って第２吸音材２２及び通気性層３２を配設したが、ルーフ部２の左右側縁部のみ又はルーフ部２の前後側縁部のみを高周波数音吸音部としてもよい。   The above embodiment is the best embodiment of the present invention, but it goes without saying that various modifications and changes can be made without departing from the scope of the claims. For example, in the above embodiment, in FIG. 2 and FIG. 3, the overlapping direction of the fiber layers of the first sound absorbing material 21 is the vehicle width direction. You may combine the width direction and the front-back direction. Further, the breathable elements 13 and 14 and the non-breathable element 15 constituting the partition layers 31 and 32 that partition the sound absorbing materials 21 and 22 and the passenger compartment are only required to be breathable or non-breathable. Even if it is composed of the above materials, it does not matter. Furthermore, in the said embodiment, the nonwoven fabric 13 layer and the urethane foam 14 layer are laminated | stacked on the ceiling surface of a vehicle interior, and the air-impermeable layer 31 and air permeability are depended on whether the resin sheet 15 exists below the sound-absorbing materials 21 and 22. However, it is also possible to divide the partition wall layer having different air permeability into a central part of the roof part 2 and a peripheral part of the roof part 2 from the beginning. Furthermore, in the above-described embodiment, the entire circumference of the roof portion 2 in the front, rear, left, and right directions is a high frequency sound absorbing portion, and the second sound absorbing material 22 and the air permeable layer 32 are disposed over the entire circumference of the roof portion 2 in the front, rear, left, and right directions. However, it is good also considering only the right-and-left side edge part of the roof part 2, or only the front-and-back side edge part of the roof part 2 as a high frequency sound absorption part.

また、図１５に示すように、面状の吸音材をジグザグに折り重ねて第１吸音材２１を作製する際に、トップシーリング材４１に隣接する第１吸音材２１の下部を広げて、水平方向に延びる空気流路５１…５１を形成するようにしてもよい（第２実施形態）。この空気流路５１…５１は、例えばエアコンの冷房用エア又は暖房用エアの流路として利用することができ、効率のよい車室の温度調節が実現する。   Further, as shown in FIG. 15, when the first sound absorbing material 21 is produced by folding the planar sound absorbing material in a zigzag manner, the lower portion of the first sound absorbing material 21 adjacent to the top sealing material 41 is expanded to be horizontal. Air channels 51... 51 extending in the direction may be formed (second embodiment). The air flow paths 51... 51 can be used, for example, as a cooling air flow path or a heating air flow path of an air conditioner, thereby realizing efficient temperature adjustment of the passenger compartment.

また、図１６に示すように、第２吸音材２２と車室とを仕切る隔壁層を構成する発泡ウレタン１４層に水平方向に延びる空気流路６１…６１を穿設するようにしてもよい（第３実施形態）。   In addition, as shown in FIG. 16, air passages 61... 61 extending in the horizontal direction may be provided in the urethane foam 14 layer constituting the partition wall layer that partitions the second sound absorbing material 22 and the passenger compartment ( Third embodiment).

また、図１７に示すように、繊維層の方向が略上下方向に沿う構成の第１吸音材２１を、予め、非通気性の袋７１（樹脂製又はアルミ箔製等）に収容しておき、この袋７１…７１をルーフパネル１１とトップシーリング材４１との間の空間内に収容・充填するようにしてもよい（第４実施形態）。この場合は、袋７１が非通気性（通気性が無いあるいは通気性が相対的に低い）であるから、前述の樹脂シート１５に相当する部材は用いなくて済む。   In addition, as shown in FIG. 17, the first sound-absorbing material 21 having a configuration in which the direction of the fiber layer is substantially in the vertical direction is stored in advance in a non-breathable bag 71 (made of resin or aluminum foil, etc.). The bags 71... 71 may be accommodated and filled in the space between the roof panel 11 and the top sealing material 41 (fourth embodiment). In this case, since the bag 71 is non-breathable (no breathability or relatively low breathability), it is not necessary to use a member corresponding to the resin sheet 15 described above.

以上、具体例を挙げて詳しく説明したように、本発明は、自動車のルーフ部で発生する低周波数から高周波数までの広範囲に亘る様々な周波数の音を効率よく合理的に吸音・低減することが可能な技術であり、走行中の自動車の車室内の騒音をルーフ部に内装した吸音材で低減する技術分野において幅広い産業上の利用可能性を有するものである。   As described above in detail with reference to specific examples, the present invention efficiently and rationally absorbs and reduces sound of various frequencies ranging from low to high frequencies generated in the roof of an automobile. This technology has a wide range of industrial applicability in the technical field of reducing noise in the interior of a running automobile with a sound absorbing material installed in the roof.

本発明の最良の実施形態に係る自動車の平面図である。1 is a plan view of an automobile according to a best embodiment of the present invention. 図１のＩ−Ｉ線に沿う縦断面図である。It is a longitudinal cross-sectional view which follows the II line | wire of FIG. 図１のＩＩ−ＩＩ線に沿う縦断面図である。It is a longitudinal cross-sectional view which follows the II-II line | wire of FIG. 音の周波数と、音の低減効果代との関係を表すグラフである。It is a graph showing the relationship between a sound frequency and a sound reduction effect cost. （ａ）は、図４におけるタイプ１の説明図、（ｂ）は、図４におけるタイプ２の説明図である。(A) is explanatory drawing of type 1 in FIG. 4, (b) is explanatory drawing of type 2 in FIG. トップシーリング材の種類と、吸音材による音の低減効果代及び空気の粒子速度との関係を調べるための自動車のレイアウト図である。FIG. 4 is a layout diagram of an automobile for examining the relationship between the type of top sealing material, the noise reduction effect margin by the sound absorbing material, and the air particle velocity. トップシーリング材の種類と、吸音材による音の低減効果代及び空気の粒子速度との関係を表すグラフである。It is a graph showing the relationship between the kind of top sealing material, the noise reduction effect margin by a sound-absorbing material, and the particle velocity of air. トップシーリング材の有無に応じ、音の周波数と、トップシーリング材の上方空間内の空気の水平方向の粒子速度との関係を表すグラフである。It is a graph showing the relationship between the frequency of sound and the horizontal particle velocity of the air in the space above the top sealing material according to the presence or absence of the top sealing material. トップシーリング材の種類に応じ、音の周波数と、トップシーリング材の上方空間内の空気の水平方向の粒子速度との関係を表すグラフである。It is a graph showing the relationship between the sound frequency and the horizontal particle velocity of the air in the space above the top sealing material according to the type of the top sealing material. トップシーリング材の有無に応じ、音の周波数と、トップシーリング材の上方空間内の空気の上下方向の粒子速度との関係を表すグラフである。It is a graph showing the relationship between the frequency of sound and the particle velocity in the vertical direction of the air in the space above the top sealing material depending on the presence or absence of the top sealing material. トップシーリング材の種類に応じ、音の周波数と、トップシーリング材の上方空間内の空気の上下方向の粒子速度との関係を表すグラフである。It is a graph showing the relationship between the frequency of sound and the vertical particle velocity of air in the space above the top sealing material according to the type of the top sealing material. ルーフ部中央部における第１吸音材の吸音効果の説明図である。It is explanatory drawing of the sound absorption effect of the 1st sound absorption material in a roof part center part. ルーフ部周縁部における第２吸音材の吸音効果の説明図である。It is explanatory drawing of the sound absorption effect of the 2nd sound absorption material in a roof part peripheral part. 音の周波数と、音が吸音材へ垂直入射したときの吸音率との関係を表すグラフである。It is a graph showing the relationship between the frequency of sound and the sound absorption rate when the sound is perpendicularly incident on the sound absorbing material. 本発明の第２の実施形態の特徴部分の説明図である。It is explanatory drawing of the characteristic part of the 2nd Embodiment of this invention. 本発明の第３の実施形態の特徴部分の説明図である。It is explanatory drawing of the characteristic part of the 3rd Embodiment of this invention. 本発明の第４の実施形態の特徴部分の説明図である。It is explanatory drawing of the characteristic part of the 4th Embodiment of this invention.

符号の説明Explanation of symbols

１ 自動車
２ ルーフ部
１１ ルーフパネル
１３ 不織布
１４ 発泡ウレタン
１５ 樹脂シート（シート部材）
２１ 第１吸音材
２２ 第２吸音材
３１ 非通気性層（隔壁層）
３２ 通気性層（隔壁層）
４１ トップシーリング材 DESCRIPTION OF SYMBOLS 1 Car 2 Roof part 11 Roof panel 13 Nonwoven fabric 14 Urethane foam 15 Resin sheet (sheet member)
21 First sound absorbing material 22 Second sound absorbing material 31 Non-breathable layer (partition wall layer)
32 Breathable layer (partition wall layer)
41 Top sealing material

Claims (4)

ルーフパネルの下方に繊維質の吸音材が配設された自動車のルーフ部構造であって、
ルーフ部中央部に吸音材の繊維方向がルーフ面に沿った方向に対して交差した方向である第１吸音材が配設され、
ルーフ部周縁部に吸音材の繊維方向がルーフ面に略沿った方向である第２吸音材が配設され、
これらの第１、第２吸音材の下方に該吸音材と車室とを仕切る隔壁層が設けられて、
該隔壁層のうち第２吸音材の下方部分の通気性が第１吸音材の下方部分の通気性よりも高くされていることを特徴とする自動車のルーフ部構造。 A roof structure of an automobile in which a fibrous sound absorbing material is disposed below the roof panel,
A first sound-absorbing material that is a direction in which the fiber direction of the sound-absorbing material intersects the direction along the roof surface at the center of the roof portion;
A second sound-absorbing material in which the fiber direction of the sound-absorbing material is a direction substantially along the roof surface is disposed on the periphery of the roof portion;
A partition wall layer that partitions the sound absorbing material and the vehicle compartment is provided below the first and second sound absorbing materials,
The roof structure of an automobile, wherein the air permeability of the lower part of the second sound absorbing material in the partition layer is higher than the air permeability of the lower part of the first sound absorbing material. 前記請求項１に記載の自動車のルーフ部構造において、
前記隔壁層のうち第１吸音材の下方部分の剛性が第２吸音材の下方部分の剛性よりも低くされていることを特徴とする自動車のルーフ部構造。 In the roof part structure of the automobile according to claim 1,
A roof structure of an automobile, wherein a rigidity of a lower part of the first sound absorbing material in the partition wall layer is lower than a rigidity of a lower part of the second sound absorbing material. 前記請求項１又は２に記載の自動車のルーフ部構造において、
前記第１吸音材は、面状の吸音材がルーフ面に略沿った方向に折り重ねられ、ルーフパネルと隔壁層との間に収容されたものであることを特徴とする自動車のルーフ部構造。 In the automobile roof structure according to claim 1 or 2,
The roof structure of an automobile, wherein the first sound absorbing material is obtained by folding a planar sound absorbing material in a direction substantially along the roof surface and accommodated between a roof panel and a partition wall layer. . 前記請求項１から３のいずれかに記載の自動車のルーフ部構造において、
前記隔壁層のうち第１吸音材の下方部分は、第２吸音材の下方部分の通気性よりも低い通気性のシート部材を含み、該シート部材がルーフ部周縁部まで延設され、第２吸音材の上方に敷設されていることを特徴とする自動車のルーフ部構造。 In the roof part structure of the automobile according to any one of claims 1 to 3,
The lower part of the first sound-absorbing material in the partition layer includes a breathable sheet member lower than the breathability of the lower part of the second sound-absorbing material, and the sheet member extends to the periphery of the roof part. A roof structure of an automobile characterized by being laid above a sound absorbing material.
JP2005338533A 2005-11-24 2005-11-24 Automobile roof structure Expired - Fee Related JP4561611B2 (en)

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Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2009220775A (en) * 2008-03-18 2009-10-01 Yamaha Corp Vehicle body structure, vehicle roof and roof inner panel
JP2009219853A (en) * 2008-02-20 2009-10-01 Mitsubishi Electric Corp Vacuum cleaner
JP2010110395A (en) * 2008-11-05 2010-05-20 Mitsubishi Electric Corp Sound-deadening structure, vacuum cleaner, and air conditioner
CN106103196A (en) * 2014-03-25 2016-11-09 林天连布有限公司 Automobile damper element

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JPH05263345A (en) * 1991-09-12 1993-10-12 Nippon Felt Kogyo Kk Fibrous layer material and its production
JPH08132990A (en) * 1994-11-08 1996-05-28 Toyota Auto Body Co Ltd Silencer pad for automobile floor
JPH1058572A (en) * 1995-07-20 1998-03-03 Bridgestone Corp Laminated molding
JP2005226178A (en) * 2004-02-10 2005-08-25 Toray Ind Inc Interior substrate for automobile and interior material for automobile
JP2005227747A (en) * 2003-10-29 2005-08-25 Takehiro:Kk Ultralightweight soundproof material
JP2005247267A (en) * 2004-03-08 2005-09-15 Mazda Motor Corp Car roof structure

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH05263345A (en) * 1991-09-12 1993-10-12 Nippon Felt Kogyo Kk Fibrous layer material and its production
JPH08132990A (en) * 1994-11-08 1996-05-28 Toyota Auto Body Co Ltd Silencer pad for automobile floor
JPH1058572A (en) * 1995-07-20 1998-03-03 Bridgestone Corp Laminated molding
JP2005227747A (en) * 2003-10-29 2005-08-25 Takehiro:Kk Ultralightweight soundproof material
JP2005226178A (en) * 2004-02-10 2005-08-25 Toray Ind Inc Interior substrate for automobile and interior material for automobile
JP2005247267A (en) * 2004-03-08 2005-09-15 Mazda Motor Corp Car roof structure

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2009219853A (en) * 2008-02-20 2009-10-01 Mitsubishi Electric Corp Vacuum cleaner
JP2009220775A (en) * 2008-03-18 2009-10-01 Yamaha Corp Vehicle body structure, vehicle roof and roof inner panel
JP2010110395A (en) * 2008-11-05 2010-05-20 Mitsubishi Electric Corp Sound-deadening structure, vacuum cleaner, and air conditioner
CN106103196A (en) * 2014-03-25 2016-11-09 林天连布有限公司 Automobile damper element

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