JP2004148978A - Support body, and pneumatic run-flat tire - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To compose a pneumatic run-flat tire capable of reducing tire noise using a general rim and a pneumatic tire. <P>SOLUTION: The pneumatic run-flat tire 10 consists of the rim 12, the pneumatic tire 14, and a support body 16. The support body 16 is equipped with a support part 26 formed with a plate, and a rubber made leg part 28. A cover member 32 is fixedly provided on the inner peripheral surface of the support part 26 to compose a sub air chamber 34. The subsidiary air chamber 34 is divided into a plurality of small subsidiary air chambers 34A in a circumferential direction with partition walls 37. One communication hole 38 is formed with respect to respective small subsidiary air chambers 34A on the support part 26, and the small subsidiary air chamber 34A and the communication hole 38 compose a Helmholtz resonant absorber reducing tire noise. Since leg parts 28 at the both ends are formed with an elastic body, the support body 16 can be assembled to the general rim 12 along with the pneumatic tire 14 in the same procedure as a rim assembly of the pneumatic tire 14. <P>COPYRIGHT: (C)2004,JPO

Description

ｆ_０（Ｈｚ）：共鳴周波数
Ｖｎ（ｃｍ^３）：副気室の体積
Ｌｎ（ｃｍ）：連通部の長さ
Ｓｎ（ｃｍ^２）：連通部の断面積
Ｃ：音速（ｃｍ／ｓ）
ここで、ｎは複数個の副気室が有る場合の、それぞれの副気室の番号である。
【００５０】
また、各副気室に複数（ｉ）の連通部が存在する場合には、それぞれの連通部の断面積をＳｉ、長さをＬｉとすると、
Ｓｎ＝ΣＳｉ（ｉ＝２〜ｉ）
Ｌｎ＝ΣＳｉ・ Ｌｉ／ΣＳｉ
として計算すれば良い。
【００５１】
請求項５に記載の発明は、請求項１乃至請求項４の何れか１項に記載の支持体において、前記副気室の総容積が、前記タイヤ気室と前記副気室とを合わせたタイヤ気室総容積の２％以上５０％以下であることを特徴としている。
【００５２】
次に、請求項５に記載の支持体の作用を説明する。
【００５３】
副気室の総容積が、タイヤ気室と副気室とを合わせたタイヤ気室総容積の２％未満になると、空洞共鳴音低減の効果が小さくなる。
【００５４】
一方、副気室の総容積が、タイヤ気室と副気室とを合わせたタイヤ気室総容積の５０％を越えると、支持体の径が大きくなり過ぎ、通常走行時に空気入りタイヤと支持体とが接触する可能性がある。
【００５５】
なお、副気室の総容積は、タイヤ気室と副気室とを合わせたタイヤ気室総容積の１０〜４０％が更に好ましい。
【００５６】
請求項６に記載の空気入りランフラットタイヤは、一対のビードコア間にわたってトロイド状に形成されたカーカスと、前記カーカスのタイヤ軸方向外側に配置されてタイヤサイド部を構成するサイドゴム層と、前記カーカスのタイヤ径方向外側に配置されてトレッド部を構成するトレッドゴム層とを備え、リムに装着されるタイヤと、前記タイヤの内側に配設され、前記タイヤと共にリムに組み付けられる請求項１乃至請求項５の何れか１項に記載の支持体と、を備えることを特徴としている。
【００５７】
請求項６に記載の空気入りランフラットタイヤの作用は、請求項１乃至請求項５に記載の支持体をリムに装着した場合の説明と同じ内容であるので、説明は省略する。
【００５８】
【発明の実施の形態】
［第１の実施形態］
本発明の第１の実施形態に係る空気入りランフラットタイヤ１０について図１乃至図３を参照して説明する。
【００５９】
図１に示すように、空気入りランフラットタイヤ１０とは、リム１２に空気入りタイヤ１４と支持体１６を組み付けたものをいう。
【００６０】
なお、本実施形態の空気入りランフラットタイヤ１０は乗用車用である。
【００６１】
リム１２は、空気入りタイヤ１４のサイズに対応した標準リムである。
【００６２】
空気入りタイヤ１４は、図１に示すように、一対のビード部１８と、両ビード部１８に跨がって延びるトロイド状のカーカス２０と、カーカス２０のクラウン部に位置する複数（本実施形態では２枚）のベルト層２２と、ベルト層２２の上部に形成されたトレッド部２４とを備えた一般的なラジアル構造のタイヤである。
【００６３】
空気入りタイヤ１４の内部に配設される支持体１６は、図１に示す断面形状のものがリング状に形成されたものであり、支持部２６と、支持部２６の両端に加硫成形されたゴム製の脚部２８とを備える。
【００６４】
脚部２８は、支持体１６をリム組み付け時に空気入りタイヤ１４の内側でリム１２に組み付けられるものであり、乗用車用の場合は高さ（径方向高さ）が２０ｍｍ〜４０ｍｍ、好ましくは２５ｍｍ〜３５ｍｍが好適である。
【００６５】
一方、支持部２６は、１枚のプレートを成形することによって図２に示す断面形状としたものであり、径方向外側に凸となる凸部３０Ａ、３０Ｂ（曲率半径Ｒ１）と、その間に形成された径方向内側に凸となる凹部３０Ｃ（曲率半径Ｒ２）、さらには凸部３０Ａ、３０Ｂの幅方向（Ｘ方向）外側（凹部３０Ｃと反対側）に荷重を支持するサイド部３０Ｄ、３０Ｅが形成されている。
【００６６】
サイド部３０Ｄ、３０Ｅの径方向内側の端部（リム側端部）には略タイヤ回転軸方向に延在するフランジ部３０Ｆ、３０Ｇが形成されている。
【００６７】
なお、支持部２６の材料に特に制限はないが、軽量化のためにＳＵＳ、高張力鋼、アルミニウム、あるいは、カーボン、ケプラー、ガラス繊維のいずれか１つあるいはその組み合わせで補強された熱硬化樹脂、熱可塑性樹脂等から形成するのが好ましい。
【００６８】
また、本実施形態では、径方向断面において（曲率半径Ｒ１）の曲面とされた部分を凸部３０Ａ、３０Ｂ（矢印Ａ、Ｂの領域）、曲率半径Ｒ２の曲面とされた部分を凹部３０Ｃ（矢印Ｃの領域）、凸部３０Ａ、３０Ｂの幅方向外側に位置して直線形状とされた部分をサイド部３０Ｄ、３０Ｅ、サイド部３０Ｄ、３０Ｅよりもさらに幅方向外側に形成され幅方向外側に延びる直線状とされた部分をフランジ部３０Ｆ、３０Ｇとする。
【００６９】
凸部３０Ａ、３０Ｂのそれぞれ径方向において最も外側の位置（以下、ピークという）Ｐ１、Ｐ２の支持体の幅方向（矢印Ｘ方向）における間隔（ピーク間距離）Ｌ１が空気入りタイヤ１４とリム１２の内部にセットされた状態における支持体１６の一対の脚部２８間の幅方向距離（脚部間距離）Ｌ２（図１参照）に対して２５％以上６０％以下の範囲、例えば４０％とされている。
【００７０】
これは、ピーク間距離Ｌ１が脚部間距離Ｌ２に対して２５％未満であると、ランフラット走行時にトレッド部２４に接する支持部２６の矢印Ｘ方向の幅が狭くなり、トレッド部２４に狭い範囲に荷重が集中して作用することによって空気入りタイヤ１４が破壊されることを防止するためである。
【００７１】
また、ピーク間距離Ｌ１が脚部間距離Ｌ２に対して６０％を越えると、凹部３０Ｃの剛性不足のためにランフラット走行時の荷重の作用によって凹部３０Ｃが凹みやすくなるためである。
【００７２】
なお、ここで脚部間距離Ｌ２とは、空気入りタイヤ１４を標準リム（リム１２）に組み付けた状態で、標準空気圧とした空気入りタイヤ１４に標準荷重を付与した場合の支持体１６の一対の脚部２８間の幅方向距離（矢印Ｘ方向）のことである。
【００７３】
なお、本実施形態のリム１２は、標準リムである。
【００７４】
ここで、標準リムとはＪＡＴＭＡ（日本自動車タイヤ協会）のＹｅａｒ Ｂｏｏｋ２００２年度版規定のリムであり、標準空気圧とはＪＡＴＭＡ（日本自動車タイヤ協会）のＹｅａｒ Ｂｏｏｋ２００２年度版の最大負荷能力に対応する空気圧であり、標準荷重とはＪＡＴＭＡ（日本自動車タイヤ協会）のＹｅａｒ Ｂｏｏｋ２００２年度版の単輪を適用した場合の最大負荷能力に相当する荷重である。
【００７５】
日本以外では、荷重とは下記規格に記載されている適用サイズにおける単輪の最大荷重（最大負荷能力）のことであり、内圧とは下記規格に記載されている単輪の最大荷重（最大負荷能力）に対応する空気圧のことであり、リムとは下記規格に記載されている適用サイズにおける標準リム（または、”Ａｐｐｒｏｖｅｄ Ｒｉｍ” 、”Ｒｅｃｏｍｍｅｎｄｅｄ Ｒｉｍ”）のことである。
【００７６】
規格は、タイヤが生産又は使用される地域に有効な産業規格によって決められている。例えば、アメリカ合衆国では、”Ｔｈｅ Ｔｉｒｅ ａｎｄ Ｒｉｍ Ａｓｓｏｃｉａｔｉｏｎ Ｉｎｃ． のＹｅａｒ Ｂｏｏｋ ”であり、欧州では”Ｔｈｅ Ｅｕｒｏｐｅａｎ Ｔｉｒｅ ａｎｄ Ｒｉｍ Ｔｅｃｈｎｉｃａｌ ＯｒｇａｎｉｚａｔｉｏｎのＳｔａｎｄａｒｄｓ Ｍａｎｕａｌ”である。
【００７７】
支持部２６の内周面には、サイド部３０Ｄとサイド部３０Ｅとを連結するリング状の蓋部材３２が接着、または溶接等で固着されている。
【００７８】
蓋部材３２は、アルミニューム、鉄等の金属、またはアクリル、ＡＢＳ、ＰＰ、ＰＥＴ等の合成樹脂で形成される。
【００７９】
ここで、空気入りタイヤ１４とリム１２とで囲まれる空間の中で、支持部２６と蓋部材３２とで囲まれる空間は副気室３４とされ、副気室３４以外の部分（空気入りタイヤ１４の内面と支持体１６との間の空間、及び支持体１６とリム１２との間の空間）は副気室３４とは独立したタイヤ気室３６とされている。
【００８０】
この副気室３４は、隔壁３７によって周方向に複数の小副気室３４Ａに分割されている。
【００８１】
隔壁３７は、ゴム等の弾性体で形成されており、支持部２６、及び蓋部材３２に接着剤等で固着されている。
【００８２】
ここで、小副気室３４Ａは４個以上形成することが好ましく、５個以上形成することが更に好ましい。
【００８３】
また、隔壁３７は、回転バランスを考えると周方向に等間隔に配置することが好ましい。
【００８４】
図２に示すように、本実施形態では、４つの隔壁３７が周方向に等間隔に配置されており、これにより副気室３４は４つの小副気室３４Ａに分割されている。
【００８５】
図１及び図２に示すように、支持部２６には、各小副気室３４Ａに対応して１つの連通孔３８が形成されている。
【００８６】
連通孔３８は小副気室３４Ａとタイヤ気室３６とを連通しており、小副気室３４Ａと連通孔３８とでヘルムホルツ共鳴吸音器を構成している。
【００８７】
即ち、本実施形態では、４つのヘルムホルツ共鳴吸音器が構成されている。
【００８８】
図３に示すように、連通孔３８の形成位置は、パンク時にタイヤ内面と接触せず、かつ小副気室３４Ａの周方向中央付近４０から外れた位置に形成することが好ましい。
【００８９】
ここで、小副気室３４Ａの周方向中央付近とは、図３に示すように、小副気室３４Ａを周方向に沿った断面で見たときに、一方の隔壁３７から隣接する他方の隔壁３７までの円弧に沿った距離を１００％としたときに、一方の隔壁３７から他方の隔壁３７までの４９〜５１％の範囲内を指す。
【００９０】
ここで、空気入りランフラットタイヤ１０において、副気室３４の容積（小副気室３４Ａの４個分の容積）は、タイヤ気室３６の容積と副気室３４の容積とを合わせたタイヤ気室総容積の２％以上５０％以下に設定することが好ましく、中でも１０％以上４０％以下が更に好ましい。
（作用）
この空気入りランフラットタイヤ１０の作用について説明する。
【００９１】
本実施形態の支持体１６は、支持部２６の両端の径方向内側端部に設けられた脚部２８が弾性体から形成されており、空気入りタイヤ１４のビード部と同様に弾性変形可能である。またプレートで形成された支持部２６もある程度捩ることが出来る。
【００９２】
したがって、支持体１６は、空気入りタイヤ１４のリム組みと同様の手順で空気入りタイヤ１４と共にリム１２に組み付けることができる。
【００９３】
したがって、リム１２は一般の汎用品を用いることができる。
【００９４】
図４に示すように、空気入りランフラットタイヤ１０は、内圧が低下した場合、空気入りタイヤ１４のトレッド部２４を支持体１６の凸部３０Ａ、３０Ｂが支持するので車両の走行が可能となる。
【００９５】
また、この際、路面からの衝撃がトレッド部２４、支持体１６、リム１２を介して車体に伝達されるが、支持体１６のリム１２と当接する部分にはゴム製の脚部２８が設けられているため、路面からの衝撃が緩衝されてランフラット走行時の乗り心地が向上すると共に、路面からの衝撃によって支持体１６（支持部２６）のサイド部３０Ｄ、３０Ｅが塑性変形してしまうことを回避できる。
【００９６】
また、ランフラット走行時、トレッド部２４は、支持部２６の凸部３０Ａ、３０ＢのうちピークＰ１、Ｐ２間の部分と当接する。
【００９７】
この結果、支持体１６の支持部２６のうち２つの凸部３０Ａ、３０ＢのピークＰ１、Ｐ２間の部分に当接したトレッド部２４の一部に局部的に荷重が作用する。
【００９８】
したがって、ピークＰ１、Ｐ２間のタイヤ幅方向距離Ｌ１を脚部間距離Ｌ２に対して２５％以上とすることによって、トレッド部２４の一部に集中的に荷重が作用してトレッド部２４（タイヤ）が破壊してしまうことを回避できる。
【００９９】
また、ピークＰ１、Ｐ２間のタイヤ幅方向距離Ｌ１が大きくなり過ぎると、凹部３０Ｃの強度が低下してランフラット走行時に凹部３０Ｃが凹んでしまうおそれがあるが、ピークＰ１、Ｐ２間のタイヤ幅方向距離Ｌ１を脚部間距離Ｌ２に対して６０％以下とすることによって、凹部３０Ｃに所定の強度を確保してランフラット走行による支持部２６の塑性変形を回避できる。
【０１００】
すなわち、空気入りランフラットタイヤ１０は、支持部２６の両凸部３０Ａ、３０ＢのピークＰ１、Ｐ２間距離Ｌ１を脚部間距離Ｌ２の２５％以上６０％以下とすることによって、ランフラット走行時にトレッド部２４の一部に荷重が集中して作用してタイヤが破損することを回避する一方、支持部２６の塑性変形も回避できる。
【０１０１】
なお、ランフラット走行時、荷重によって支持部２６が弾性変形した場合、これに固着されている隔壁３７もゴム等の弾性変形可能な材料で形成されているため、弾性変形する。
【０１０２】
一方、通常の走行時においては、副気室３４と連通孔３８とがヘルムホルツ共鳴吸音器として機能する。
【０１０３】
例えば、一般的な乗用車用タイヤでは、およそ２５０Ｈｚ付近に空洞共鳴と考えられピークが存在しており、車内騒音の一因となっているが、本実施形態の空気入りランフラットタイヤ１０では、小副気室３４Ａの容積、連通孔３８の断面積、長さ等を適宜選択する事、即ち、ヘルムホルツ共鳴吸音器の共鳴周波数を空洞共鳴の周波数と一致させることにより、この空洞共鳴音を大巾に低減する事ができる。
【０１０４】
また、本実施形態では、小副気室３４Ａが周方向に連続していないので、新たな空洞共鳴を副気室内部で発生させることが無い。
【０１０５】
ここで、小副気室３４Ａの数が４個未満では、空洞共鳴音の改善効果が不足する。
【０１０６】
副気室３４の容積が、タイヤ気室３６と副気室３４とを合わせたタイヤ気室総容積の２％未満になると、空洞共鳴音低減の効果が小さくなる。
【０１０７】
一方、副気室３４の容積が、タイヤ気室３６と副気室３４とを合わせたタイヤ気室総容積の５０％を越えると、支持体１６の径が大きくなり過ぎ、通常走行時に空気入りタイヤ１４と支持体１６とが接触する可能性がある。
【０１０８】
また、ヘルムホルツ共鳴吸音器の機能を得るために連通孔３８の断面積は比較的小さく設定されるので、タイヤ変形時のタイヤ気室３６と小副気室３４Ａとの間の気体流通に対して抵抗を生じ、タイヤ変形に起因する振動の減衰性が向上する。
【０１０９】
このため、道路の突起を乗り越した際などに生じる振動の減衰性を高めることができ、急なハンドル操作や高速走行などの高周波の入力に対しては、見掛けのタイヤ動バネ定数が上がり、操縦安定性を向上できる。
【０１１０】
なお、低減させたい周波数の振動が複数ある場合（例えば、周波数特性に複数のピークがある場合）には、各小副気室３４Ａの容積、形状、各連通孔３８の断面積及び長さ等を適宜選択することにより、複数の周波数の振動に対応することもできる。
【０１１１】
本実施形態では、小副気室３４Ａは１つの連通孔３８でタイヤ気室３６と連通していたが、１つの小副気室３４Ａに対して２以上の連通孔３８を対応させても良い。
【０１１２】
また、本実施形態では、連通孔３８が円形であったが、円形以外であっても良いのは勿論であり、空気が通過できるものであれば、連通孔３８の代わりにスリット、パイプ等の管状体を用いてタイヤ気室３６と小副気室３４Ａとを連通させても良い。
【０１１３】
また、小副気室３４Ａの内部に、グラスウール、スポンジ等の綿状体やフォーム状の消音剤（吸音材）を充填することや、内壁に貼り付けることもでき、これにより吸音効果を更に高めることもできる。
【０１１４】
なお、本実施形態の空気入りランフラットタイヤ１０は乗用車用であるが、本発明は、トラック、バス等の他の車両用のランフラットタイヤにも適用可能であることは勿論である。
【０１１５】
空洞共鳴周波数が２５０Ｈｚである一般的な乗用車用タイヤの場合、ヘルムホルツ共鳴吸音器の共鳴周波数は１００〜５００Ｈｚの範囲内であれば、空洞共鳴音低減効果はある。
【０１１６】
また、現在のタイヤサイズの構成からすると、各タイヤの共鳴周波数はおおよそ１８０〜３００Ｈｚの範囲にあるので、ヘルムホルツ共鳴吸音器の共鳴周波数も、この範囲になるように各寸法を調整することがより大きな減音効果を得る為に好ましい。
［第２の実施形態］
次に、本発明の第２の実施形態に係る空気入りランフラットタイヤ４２を図５、及び図６にしたがって説明する。なお、第１の実施形態と同一構成には同一符号を付し、その説明は省略する。
【０１１７】
図５、及び図６に示すように、本実施形態の支持体４４は、支持部２６、脚部２８、及び後述する隔壁３７で構成されている。
【０１１８】
本実施形態では、支持体１６とリム１２とで囲まれる空間が副気室３４とされ、空気入りタイヤ１４と支持体１６とで囲まれるタイヤ気室３６とされている。
【０１１９】
本実施形態の副気室３４は、肉厚のゴム等の弾性体で形成された隔壁４６によって周方向に複数の小副気室３４Ａに分割されている。
【０１２０】
隔壁４６は、支持体１６の内周面に接着されている。
【０１２１】
なお、隔壁４６の内周側の端縁は、脚部２８と共にリム１２の外周面に圧接している。
【０１２２】
空気入りランフラットタイヤ４２においても、小副気室３４Ａと連通孔３８とでヘルムホルツ共鳴吸音器が構成されているので、第１の実施形態の空気入りランフラットタイヤ１０と同様の作用、効果が得られる。
【０１２３】
なお、本実施形態の空気入りランフラットタイヤ４２では、隔壁４６がゴム等の弾性体で形成されているため、パンク時には脚部２８と共に弾性変形してショックを吸収することができる。
（試験例）
本発明の効果を確かめるために、比較例（コントロール品：従来のリムホイールとタイヤとの組み合わせ品）の空気入りタイヤ１種類と、本発明の適用された実施例の空気入りランフラットタイヤ２種類を試作し、通常の路面を模したドラム上に押し付け、一定速度で走行させた際のタイヤ騒音を測定した。
【０１２４】
また、支持体の効果を確かめるために、比較例の空気入りタイヤを装着した乗用車と実施例の空気入りランフラットタイヤを装着した乗用車を用い、右前輪の空気圧を０としてパンク時の耐久試験を行った。
【０１２５】
走行は、速度９０ｋｍ／ｈで直線や緩やかなカーブを有する周回路で試験を実施した。
【０１２６】
比較例：リムサイズ６ＪＪ１４の通常のアルミホイールに１８５／６０Ｒ１４サイズの通常の乗用車用タイヤを装着したものである。
【０１２７】
タイヤ気室の容積は、３５０００ｃｍ^３である。
【０１２８】
実施例１：第１の実施形態（図１参照）で示した構造の空気入りランフラットタイヤであり、タイヤ、及びホイールは比較例と同一品である。
【０１２９】
副気室の総容積は、１２００ｃｍ^３であり、タイヤ気室総容積（タイヤ気室と副気室を合わせた容積）の３．４％である。
【０１３０】
各小副気室には、それぞれ直径０．５ｃｍ、長さ０．２ｃｍの連通孔を１個づつ設け、ヘルムホルツ共鳴吸音器の共鳴周波数を２３０Ｈｚに設定した。
【０１３１】
実施例２：第２の実施形態（図５参照）で示した構造の空気入りランフラットタイヤであり、タイヤは、及びホイールは比較例と同一品である。
【０１３２】
副気室の総容積は、３０００ｃｍ^３であり、タイヤ気室総容積（タイヤ気室と副気室を合わせた容積）の８．６％である。
【０１３３】
各小副気室には、それぞれ直径１．０ｃｍ、長さ０．２ｃｍの連通孔を１個づつ設け、ヘルムホルツ共鳴吸音器の共鳴周波数を２４０Ｈｚに設定した。。
【０１３４】
内圧は、比較例及び実施例１，２の何れも２００ｋＰａとした。
【０１３５】
試験は、空気入りランフラットタイヤを荷重４００ｋｇｆでドラムに押し付け、速度６０ｋｍ／ｈで走行させた際の、上下方向のドラム軸力を測定し、周波数解析を行った。なお、試験に用いたドラムは直径３ｍで、表面に一般的な道路形状を模したアスファルトが貼り付けてある。本試験は、振動として車内に伝わる、所謂ロードノイズの試験法である。
【０１３６】
以下の表１には、試験結果が示されている。
【０１３７】
【表１】

試験の結果、実施例１，２の空気入りランフラットタイヤは、比較例の空気入りタイヤ対比で空洞共鳴音が大巾に低減されている事が確かめられた。
【０１３８】
また、実施例１，２の空気入りランフラットタイヤは、故障までの走行距離が長く、耐久性が大幅に向上していることが分る。
【０１３９】
【発明の効果】
以上説明したように本発明の請求項１に記載の支持体は上記の構成としたので、汎用のリムに空気入りタイヤと共に装着して騒音の低減を可能とする空気入りランフラットタイヤを構成することができる、という優れた効果を有する。
【０１４０】
請求項２に記載の支持体は上記の構成としたので、汎用のリムに空気入りタイヤと共に装着して騒音の低減を可能とする空気入りランフラットタイヤを構成することができる、という優れた効果を有する。
【０１４１】
請求項３に記載の支持体は上記の構成としたので、区画した副気室の容積、連通部の寸法をそれぞれ変えて、共鳴周波数をずらす事が出来るようになり、広い周波数範囲に渡って騒音を低減できる、という優れた効果を有する。
【０１４２】
請求項４に記載の支持体は上記の構成としたので、１００〜５００Ｈｚの騒音を低減できる、という優れた効果を有する。
【０１４３】
請求項５に記載の支持体は上記の構成としたので、通常走行時に空気入りタイヤと支持体を接触させず、空洞共鳴音低減の効果を確実に得ることができる。
【０１４４】
請求項６に記載の空気入りランフラットタイヤは上記の構成としたので、汎用のリム及び空気入りタイヤを用いてタイヤ騒音の低減を図ることができる、という優れた効果を有する。
【図面の簡単な説明】
【図１】本発明の第１の実施形態に係る空気入りランフラットタイヤの一部を断面にした斜視図である。
【図２】第１の実施形態に係る空気入りランフラットタイヤの軸線に直角な断面図である。
【図３】第１の実施形態に係る空気入りランフラットタイヤに用いた支持体の軸線に直角な断面図である。
【図４】内圧零時の空気入りランフラットタイヤの断面図である。
【図５】本発明の第２の実施形態に係る空気入りランフラットタイヤの一部を断面にした斜視図である。
【図６】第２の実施形態に係る空気入りランフラットタイヤに用いた支持体の軸線に直角な断面図である。
【符号の説明】
１０ 空気入りランフラットタイヤ
１２ リム
１４ 空気入りタイヤ
１６ 支持体
２４ トレッド部
２６ 支持部
２８ 脚部
３２ 蓋部材（副気室形成部材）
３４ 副気室
３４Ａ 小副気室
３６ タイヤ気室
３７ 隔壁
３８ 連通孔（連通部）
４２ 空気入りランフラットタイヤ
４４ 支持体
４６ 隔壁[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an annular support disposed inside the tire so that it can travel a considerable distance in that state when punctured, and a pneumatic runflat tire in which the support is disposed inside. In addition, the present invention relates to a support capable of suppressing vibration transmitted to a vehicle, improving ride comfort, and reducing vehicle interior noise, and a pneumatic run-flat tire in which the support is disposed.
[0002]
[Prior art]
Run flat running is possible with pneumatic tires, that is, the tires are punctured and the tire internal pressure is 0 kg / cm ² As a tire (hereinafter referred to as a run-flat tire) that can travel with a certain distance without worry, a metal or synthetic resin annular support ( A core type with a core is known.
[0003]
As the core type, a type using a hollow support is known (for example, see Patent Document 1).
[0004]
This support pair functions as a Helmholtz resonance sound absorber, and can reduce tire noise during normal running.
[0005]
[Patent Document 1]
JP-A-2-234304 (specifications, pages 1 to 12; FIGS. 1 to 15).
[0006]
[Problems to be solved by the invention]
However, there has been a problem that the conventional support cannot be attached unless a special rim is used.
[0007]
In view of the above facts, the present invention provides a support capable of forming a pneumatic run-flat tire capable of reducing noise when mounted on a general-purpose rim together with a pneumatic tire, and a tire using a general-purpose rim and a pneumatic tire. It is an object of the present invention to provide a pneumatic run-flat tire capable of reducing noise.
[0008]
[Means for Solving the Problems]
The invention according to claim 1 is an annular support that is disposed inside a pneumatic tire, is assembled to the rim together with the pneumatic tire, and is capable of supporting a load during run-flat running. In cross section, a curved linear support including two projecting portions projecting radially outward and side portions extending radially inward outside the radial direction of the projecting portion from the radially outermost position. Part, an elastic body integrated with the radially inner end of the side part, a leg mounted on the rim when assembling the rim, and a sub-part that forms a discontinuous sub-air chamber with at least the support part. An air chamber forming member, and a sub air chamber with respect to a tire air chamber provided between at least one of the support portion and the leg portion and formed between the tire inner surface and the rim with at least the tire inner surface as a part of a partition wall And a communication unit that communicates Has the additional air chamber and said communicating portion functions as a Helmholtz resonator sound absorber is characterized by.
[0009]
The operation of the support according to claim 1 will be described.
[0010]
Since the leg provided at the radially inner end of the support is made of an elastic body, it can be elastically deformed similarly to the bead of a normal pneumatic tire. Accordingly, the support can be assembled to the rim together with the pneumatic tire in the same procedure as the rim assembly for the pneumatic tire.
[0011]
Therefore, a general-purpose general-purpose product can be used for the rim.
[0012]
When the run-flat tire thus assembled is mounted on a car and run, when the internal pressure decreases, the support disposed in the tire air chamber supports the load instead of the side rubber layer of the pneumatic tire, and the run flat Running becomes possible.
[0013]
Further, a sub-air chamber that is discontinuous in the circumferential direction is formed in the support disposed in the tire air chamber, and the sub-air chamber and the communication portion function as a Helmholtz resonance sound absorber.
[0014]
Therefore, by appropriately selecting the volume of the sub-air chamber, the cross-sectional area of the communication portion, the length, and the like for the sound of the specific frequency to be reduced, the resonance sound absorbing effect can be exhibited in the sub-air chamber.
[0015]
In addition, if the secondary air chamber is continuous in the circumferential direction, not only does not function as a Helmholtz resonance sound absorber, a new cavity resonance is generated inside the secondary air chamber, and the sound reduction effect cannot be exhibited, In the present invention, such a problem does not occur because the auxiliary air chamber is discontinuous in the circumferential direction.
[0016]
Since the internal sub air chamber must not be formed in an annular shape, it is preferable to provide a partition at any part in the circumferential direction.
[0017]
Passenger car tires have a peak at about 250 Hz which is considered to be cavity resonance, which contributes to in-vehicle noise. However, by appropriately setting the above factors, this cavity resonance is greatly reduced. You can do it.
[0018]
Further, the embodiment of the present invention also provides a favorable improvement effect on the damping of vibration caused by input to the tire.
[0019]
Since the cross-sectional area of the communication portion is set relatively small in order to obtain the function of the Helmholtz resonance sound absorber, resistance is generated with respect to the gas flow between the tire air chamber and the auxiliary air chamber when the tire is deformed.
[0020]
Therefore, the damping property of the vibration caused by the tire deformation is improved.
[0021]
For example, it is possible to enhance the damping of vibrations generated when the vehicle gets over a projection on a road.
[0022]
In addition, for a high-frequency input such as a sudden steering operation or a high-speed running, an apparent tire dynamic spring constant is increased, and steering stability can be improved.
[0023]
Further, it is preferable to apply a lubricant such as silicone oil to the surface of the support or the inner surface of the tire in order to suppress frictional heat between the inner surface of the tire and the support at the time of puncturing.
[0024]
As described above, the present invention provides a pneumatic pump that achieves good run-flat running resistance while reducing weight, suppresses vibration transmitted to the vehicle, improves ride comfort, and reduces vehicle interior noise. A support that can be applied to a run flat tire can be provided.
[0025]
The invention according to claim 2 is an annular support that is provided inside a pneumatic tire, is assembled to the rim together with the pneumatic tire, and can support a load during run-flat running, and the diameter of the support is In the cross-section in the direction, a curved linear shape including two convex portions protruding outward in the radial direction and side portions extending radially inward outside in the width direction than the radially outermost positions of the convex portions was formed. A support portion, an elastic body integrated with a radially inner end of the side portion, a leg portion mounted on the rim when assembling the rim, and the support portion and the leg when mounted on the rim. And a sub-air chamber forming member formed of an elastic body that forms a sub-air chamber that is discontinuous in the circumferential direction between the portion and the rim; As part of the tire inner surface and rim Anda communicating portion for communicating the sub air chamber with respect to the tire air chamber formed between the additional air chamber and said communicating portion functions as a Helmholtz resonator sound absorber is characterized by.
[0026]
The operation of the support according to claim 2 will be described.
[0027]
Since the leg provided at the radially inner end of the support is made of an elastic body, it can be elastically deformed similarly to the bead of a normal pneumatic tire. Further, a sub air chamber forming member that forms a sub air chamber between the support portion, the leg portion, and the rim is formed of an elastic body, and can be elastically deformed similarly to the leg portion.
[0028]
Therefore, the support according to claim 2 can be assembled to the rim together with the pneumatic tire in the same procedure as the rim assembly of the pneumatic tire, similarly to the support according to claim 1.
[0029]
Other functions and effects are the same as those of the support according to the first aspect.
[0030]
According to a third aspect of the present invention, in the support according to the first or second aspect, a plurality of partition walls for dividing the sub air chamber into a plurality of sections are provided.
[0031]
Next, the operation of the support according to the third aspect will be described.
[0032]
As described above, if the auxiliary air chamber is continuous in the circumferential direction, it will not function as a Helmholtz resonance sound absorber, and it will not be possible to reduce cavity resonance.
[0033]
Therefore, in order to make the auxiliary air chamber discontinuous in the circumferential direction, it is important as one means to provide a partition wall in the core in advance.
[0034]
Strict airtightness is not required between the sub air chambers of the present partition, but it is preferable to set the partition so that there is as little gap as possible in order to achieve a greater noise reduction effect.
[0035]
It is important to form a plurality of sub-air chambers by providing a plurality of partition walls in order to provide versatility in performance.
[0036]
For a specific rim size, it is assumed that tires of several sizes (heights) are mounted, but the frequency of cavity resonance is determined by the inner circumference of the tire tread and the outer circumference of the rim, and the same rim is used. However, if the height (flatness) of the mounted tire changes, the frequency of the cavity resonance sound changes.
[0037]
When the number of sub air chambers is increased, the resonance frequency can be shifted by changing the size of these communicating portions or the volume of the air chambers, so that versatility can be provided.
[0038]
It is preferable to shift the resonance frequency of each sub-air chamber by, for example, about 10 to 30 Hz.
[0039]
The number of sub air chambers is not particularly limited as long as it is plural, but is preferably three or more.
[0040]
Further, it is preferable that the positions of the partition walls are equally distributed on the circumference in terms of rotational balance.
[0041]
In addition, even if a certain tire size is determined, the frequency may change depending on the load conditions, etc., the peak may be broad, or there may be two peaks. It is preferable to shift the resonance frequency.
[0042]
According to a fourth aspect of the present invention, in the support according to any one of the first to third aspects, the resonance frequency of the Helmholtz resonance sound absorber including the sub air chamber and the communication portion is 100. The frequency is set within a range of up to 500 Hz.
[0043]
Next, the operation of the support according to claim 4 will be described.
[0044]
The cavity resonance frequency in the tire chamber is determined by the circumference of the tire and the rim. This frequency is high for small tires for mini vehicles and low for large truck tires.
[0045]
The present inventors have examined using a general passenger car tire having a cavity resonance frequency of 250 Hz, and confirmed that the cavity resonance sound reduction effect was obtained even when the setting was within a range of 100 to 500 Hz.
[0046]
Therefore, a relatively wide range setting as described above is allowed in a closed space called a tire.
[0047]
According to the configuration of the current tire size, the resonance frequency of each tire is in a range of approximately 180 to 300 Hz, and adjusting the respective dimensions so that the set frequency of the Helmholtz resonance sound absorber also falls in this range can greatly reduce the frequency. It is preferable to obtain a sound effect.
[0048]
In addition, the resonance frequency of the Helmholtz resonance sound absorber composed of the sub air chamber and the communication part can be obtained by the following equation (1), for example.
[0049]
(Equation 1)

f ₀ (Hz): resonance frequency
Vn (cm ³ ): Volume of secondary air chamber
Ln (cm): Length of communication part
Sn (cm ² ): Cross-sectional area of communication part
C: speed of sound (cm / s)
Here, n is the number of each sub air chamber when there are a plurality of sub air chambers.
[0050]
When a plurality of (i) communicating portions exist in each sub-air chamber, the cross-sectional area of each communicating portion is Si, and the length is Li.
Sn = ΣSi (i = 2 to i)
Ln = ΣSi ・ Li / ΣSi
It should be calculated as
[0051]
According to a fifth aspect of the present invention, in the support according to any one of the first to fourth aspects, a total volume of the sub air chamber is equal to a sum of the tire air chamber and the sub air chamber. It is characterized in that it is 2% or more and 50% or less of the total volume of the tire air chamber.
[0052]
Next, the operation of the support according to claim 5 will be described.
[0053]
When the total volume of the sub air chamber is less than 2% of the total volume of the tire air chamber including the tire air chamber and the sub air chamber, the effect of reducing the cavity resonance sound is reduced.
[0054]
On the other hand, if the total volume of the auxiliary air chamber exceeds 50% of the total volume of the tire air chamber including the tire air chamber and the auxiliary air chamber, the diameter of the support becomes too large and the pneumatic tire and the support during normal driving are too large. Contact with the body is possible.
[0055]
The total volume of the sub air chamber is more preferably 10 to 40% of the total volume of the tire air chamber combined with the tire air chamber and the sub air chamber.
[0056]
The pneumatic run-flat tire according to claim 6, wherein the carcass is formed in a toroidal shape between a pair of bead cores, a side rubber layer disposed outside the carcass in the tire axial direction to form a tire side portion, and the carcass. A tread rubber layer constituting a tread portion disposed outside the tire in the radial direction of the tire, the tire being mounted on a rim, and being disposed inside the tire and being assembled to the rim together with the tire. And a support according to any one of the above items (5).
[0057]
The operation of the pneumatic run-flat tire according to claim 6 is the same as the description of the case where the support according to claims 1 to 5 is mounted on the rim, and a description thereof will be omitted.
[0058]
BEST MODE FOR CARRYING OUT THE INVENTION
[First Embodiment]
A pneumatic run-flat tire 10 according to a first embodiment of the present invention will be described with reference to FIGS.
[0059]
As shown in FIG. 1, a pneumatic run-flat tire 10 is a rim 12 on which a pneumatic tire 14 and a support 16 are assembled.
[0060]
The pneumatic runflat tire 10 of the present embodiment is for a passenger car.
[0061]
The rim 12 is a standard rim corresponding to the size of the pneumatic tire 14.
[0062]
As shown in FIG. 1, the pneumatic tire 14 includes a pair of bead portions 18, a toroidal carcass 20 extending across both the bead portions 18, and a plurality of carcass 20 located in a crown portion of the carcass 20 (the present embodiment). This is a general radial tire having two (2) belt layers 22 and a tread portion 24 formed on the belt layer 22.
[0063]
The support 16 disposed inside the pneumatic tire 14 has the cross-sectional shape shown in FIG. 1 formed in a ring shape, and is vulcanized and formed at both ends of the support 26 and the support 26. Rubber legs 28.
[0064]
The leg 28 is mounted on the rim 12 inside the pneumatic tire 14 when the support 16 is mounted on the rim, and has a height (radial height) of 20 to 40 mm, preferably 25 to 40 mm for a passenger car. 35 mm is preferred.
[0065]
On the other hand, the support portion 26 has a cross-sectional shape shown in FIG. 2 by molding a single plate, and has convex portions 30A and 30B (radius of curvature R1) that protrude outward in the radial direction, and formed between them. The concave portion 30C (radius of curvature R2) which becomes convex inward in the radial direction, and the side portions 30D and 30E which support the load in the width direction (X direction) outside (the opposite side to the concave portion 30C) of the convex portions 30A and 30B. Is formed.
[0066]
Flanges 30F, 30G extending substantially in the tire rotation axis direction are formed at radially inner ends (rim-side ends) of the side portions 30D, 30E.
[0067]
There is no particular limitation on the material of the supporting portion 26, but a thermosetting resin reinforced with SUS, high-strength steel, aluminum, or one or a combination of carbon, Kepler, and glass fiber for weight reduction. , And a thermoplastic resin.
[0068]
Further, in the present embodiment, in the radial cross section, a portion having a curved surface (curvature radius R1) is a convex portion 30A, 30B (region of arrow A, B), and a portion having a curved surface with a curvature radius R2 is concave portion 30C ( (The region indicated by the arrow C), the linear portions located outside the protrusions 30A and 30B in the width direction are formed further outside in the width direction than the side portions 30D and 30E, and the side portions 30D and 30E, and are formed outward in the width direction. The extended linear portions are referred to as flange portions 30F and 30G.
[0069]
The distance (peak distance) L1 between the outermost positions (hereinafter, referred to as peaks) P1 and P2 in the width direction (arrow X direction) of the support body in the radial direction of the protrusions 30A and 30B is the pneumatic tire 14 and the rim 12. In a range of 25% or more and 60% or less, for example, 40% with respect to a width direction distance (a distance between the legs) L2 (see FIG. 1) between the pair of legs 28 of the support 16 in a state where the support 16 is set inside. Have been.
[0070]
This is because when the distance L1 between the peaks is less than 25% of the distance L2 between the legs, the width of the support portion 26 in contact with the tread portion 24 in the direction of the arrow X during run flat running becomes narrower and narrower than the tread portion 24. This is to prevent the pneumatic tire 14 from being broken due to a concentrated load acting on the range.
[0071]
If the distance L1 between the peaks exceeds 60% of the distance L2 between the legs, the concave portion 30C tends to be dented due to the action of a load during run flat running due to insufficient rigidity of the concave portion 30C.
[0072]
Here, the distance L2 between the legs is defined as a pair of the supports 16 when a standard load is applied to the pneumatic tire 14 with the standard pneumatic pressure in a state where the pneumatic tire 14 is mounted on the standard rim (rim 12). In the width direction between the legs 28 (in the direction of the arrow X).
[0073]
Note that the rim 12 of the present embodiment is a standard rim.
[0074]
Here, the standard rim is a rim specified in JATMA (Japan Automobile Tire Association) Year Book 2002 edition, and the standard air pressure is an air pressure corresponding to the maximum load capacity in JATMA (Japan Automobile Tire Association) Year Book 2002 edition. The standard load is a load corresponding to the maximum load capacity when a single wheel of the Year Book 2002 version of JATMA (Japan Automobile Tire Association) is applied.
[0075]
Outside Japan, the load is the maximum load (maximum load capacity) of a single wheel at the applicable size described in the following standard, and the internal pressure is the maximum load (maximum load of the single wheel) described in the following standard Rim) means a standard rim (or “Approved Rim” or “Recommended Rim”) in an applicable size described in the following standard.
[0076]
Standards are determined by industry standards that are in effect in the area where the tire is manufactured or used. For example, in the United States it is "The Book of The Tire and Rim Association Inc." and in Europe it is "Standards Manual of the European Tire and Rim Technical Organization".
[0077]
A ring-shaped lid member 32 for connecting the side portion 30D and the side portion 30E is fixed to the inner peripheral surface of the support portion 26 by bonding or welding.
[0078]
The lid member 32 is formed of a metal such as aluminum or iron, or a synthetic resin such as acrylic, ABS, PP, or PET.
[0079]
Here, in the space surrounded by the pneumatic tire 14 and the rim 12, the space surrounded by the support portion 26 and the lid member 32 is a sub air chamber 34, and a portion other than the sub air chamber 34 (the pneumatic tire 34). The space between the inner surface of the support 14 and the support 16 and the space between the support 16 and the rim 12) are tire air chambers 36 independent of the auxiliary air chamber 34.
[0080]
The sub air chamber 34 is divided into a plurality of small sub air chambers 34A in the circumferential direction by a partition wall 37.
[0081]
The partition wall 37 is formed of an elastic body such as rubber, and is fixed to the support portion 26 and the lid member 32 with an adhesive or the like.
[0082]
Here, it is preferable that four or more small auxiliary air chambers 34A be formed, and it is more preferable that five or more small auxiliary air chambers be formed.
[0083]
The partition walls 37 are preferably arranged at equal intervals in the circumferential direction in consideration of rotational balance.
[0084]
As shown in FIG. 2, in the present embodiment, four partition walls 37 are arranged at equal intervals in the circumferential direction, whereby the sub air chamber 34 is divided into four small sub air chambers 34A.
[0085]
As shown in FIGS. 1 and 2, one communication hole 38 is formed in the support portion 26 so as to correspond to each small auxiliary air chamber 34 </ b> A.
[0086]
The communication hole 38 communicates the small auxiliary air chamber 34A with the tire air chamber 36, and the small auxiliary air chamber 34A and the communication hole 38 constitute a Helmholtz resonance sound absorber.
[0087]
That is, in this embodiment, four Helmholtz resonance sound absorbers are configured.
[0088]
As shown in FIG. 3, it is preferable that the communication hole 38 be formed at a position that does not contact the inner surface of the tire at the time of puncturing and that is outside the vicinity 40 of the small auxiliary air chamber 34 </ b> A in the circumferential direction.
[0089]
Here, the vicinity of the center in the circumferential direction of the small auxiliary air chamber 34A is, as shown in FIG. 3, when the small auxiliary air chamber 34A is viewed in a cross section along the circumferential direction, the other adjacent to the other partition 37 from the other partition 37. Assuming that the distance along the arc to the partition 37 is 100%, the distance from one partition 37 to the other partition 37 is in the range of 49 to 51%.
[0090]
Here, in the pneumatic run-flat tire 10, the volume of the auxiliary air chamber 34 (the capacity of four small auxiliary air chambers 34 </ b> A) is a tire obtained by combining the volume of the tire air chamber 36 and the volume of the auxiliary air chamber 34. It is preferably set to 2% or more and 50% or less of the total volume of the air chamber, and more preferably 10% or more and 40% or less.
(Action)
The operation of the pneumatic run flat tire 10 will be described.
[0091]
In the support 16 of the present embodiment, legs 28 provided at radially inner ends at both ends of the support portion 26 are formed of an elastic body, and can be elastically deformed similarly to the bead portion of the pneumatic tire 14. is there. Further, the support portion 26 formed of a plate can be twisted to some extent.
[0092]
Therefore, the support 16 can be assembled to the rim 12 together with the pneumatic tire 14 in the same procedure as the rim assembly of the pneumatic tire 14.
[0093]
Therefore, a general-purpose product can be used for the rim 12.
[0094]
As shown in FIG. 4, in the pneumatic run-flat tire 10, when the internal pressure is reduced, the tread portion 24 of the pneumatic tire 14 is supported by the protrusions 30 </ b> A and 30 </ b> B of the support 16, so that the vehicle can run. .
[0095]
At this time, the impact from the road surface is transmitted to the vehicle body via the tread portion 24, the support 16 and the rim 12, and a rubber leg 28 is provided at a portion of the support 16 which contacts the rim 12. As a result, the impact from the road surface is buffered to improve the riding comfort during run-flat running, and the side portions 30D and 30E of the support 16 (support portion 26) are plastically deformed by the impact from the road surface. Can be avoided.
[0096]
Also, during run flat traveling, the tread portion 24 comes into contact with a portion between the peaks P1 and P2 of the convex portions 30A and 30B of the support portion 26.
[0097]
As a result, a load is locally applied to a part of the tread portion 24 abutting on a portion between the peaks P1 and P2 of the two convex portions 30A and 30B of the support portion 26 of the support 16.
[0098]
Therefore, by setting the distance L1 between the peaks P1 and P2 in the tire width direction to be 25% or more of the distance L2 between the legs, a load is concentrated on a part of the tread portion 24 and the tread portion 24 (the tire ) Can be prevented from being destroyed.
[0099]
If the distance L1 in the tire width direction between the peaks P1 and P2 is too large, the strength of the concave portion 30C may be reduced and the concave portion 30C may be dented during run flat running, but the tire width between the peaks P1 and P2 may be reduced. By setting the directional distance L1 to be equal to or less than 60% of the distance L2 between the legs, a predetermined strength is secured in the concave portion 30C, and the plastic deformation of the support portion 26 due to run flat traveling can be avoided.
[0100]
That is, the pneumatic run-flat tire 10 has a configuration in which the distance L1 between the peaks P1 and P2 of the biconvex portions 30A and 30B of the support portion 26 is not less than 25% and not more than 60% of the distance L2 between the legs, so that the run-flat running tire 10 can be used. While it is possible to prevent the load from being concentrated on a part of the tread portion 24 and acting on the tire to damage the tire, it is also possible to prevent the support portion 26 from being plastically deformed.
[0101]
Note that, when the support portion 26 is elastically deformed by a load during run flat running, the partition 37 fixed to the support portion 26 is also elastically deformed because it is formed of an elastically deformable material such as rubber.
[0102]
On the other hand, during normal traveling, the auxiliary air chamber 34 and the communication hole 38 function as a Helmholtz resonance sound absorber.
[0103]
For example, in a general passenger car tire, a peak is considered at about 250 Hz, which is considered to be a cavity resonance, and this contributes to the inside noise. However, in the pneumatic run-flat tire 10 of the present embodiment, a small By appropriately selecting the volume of the auxiliary air chamber 34A, the cross-sectional area of the communication hole 38, the length, and the like, that is, by matching the resonance frequency of the Helmholtz resonance sound absorber with the frequency of the cavity resonance, the cavity resonance Can be reduced.
[0104]
Further, in the present embodiment, since the small auxiliary air chamber 34A is not continuous in the circumferential direction, no new cavity resonance is generated inside the auxiliary air chamber.
[0105]
Here, when the number of the small auxiliary air chambers 34A is less than four, the effect of improving the cavity resonance sound is insufficient.
[0106]
When the volume of the sub air chamber 34 is less than 2% of the total volume of the tire air chambers including the tire air chamber 36 and the sub air chamber 34, the effect of reducing the cavity resonance sound is reduced.
[0107]
On the other hand, when the volume of the sub air chamber 34 exceeds 50% of the total volume of the tire air chambers including the tire air chamber 36 and the sub air chamber 34, the diameter of the support 16 becomes too large, and the pneumatic air enters during normal driving. The tire 14 may come into contact with the support 16.
[0108]
Further, since the cross-sectional area of the communication hole 38 is set relatively small in order to obtain the function of the Helmholtz resonance sound absorber, the gas flow between the tire air chamber 36 and the small auxiliary air chamber 34A when the tire is deformed is reduced. Resistance is generated, and the damping of vibrations caused by tire deformation is improved.
[0109]
As a result, it is possible to increase the damping of vibrations generated when the vehicle rides over a bump on the road, and the apparent tire dynamic spring constant increases for high-frequency input such as sudden steering operation or high-speed driving, resulting in increased steering. Stability can be improved.
[0110]
When there are a plurality of vibrations of the frequency to be reduced (for example, when there are a plurality of peaks in the frequency characteristic), the volume and shape of each small auxiliary air chamber 34A, the cross-sectional area and the length of each communication hole 38, and the like By appropriately selecting, vibrations at a plurality of frequencies can be handled.
[0111]
In the present embodiment, the small auxiliary air chamber 34A communicates with the tire air chamber 36 through one communication hole 38, but two or more communication holes 38 may correspond to one small auxiliary air chamber 34A. .
[0112]
Further, in the present embodiment, the communication hole 38 is circular. However, it is needless to say that the communication hole 38 may have a shape other than a circle. The tire air chamber 36 and the small auxiliary air chamber 34A may be communicated by using a tubular body.
[0113]
In addition, the inside of the small auxiliary air chamber 34A can be filled with a cotton-like body such as glass wool or sponge or a foam-like sound absorbing material (sound absorbing material) or attached to the inner wall, thereby further enhancing the sound absorbing effect. You can also.
[0114]
Although the pneumatic runflat tire 10 of the present embodiment is for a passenger car, the present invention is of course applicable to runflat tires for other vehicles such as trucks and buses.
[0115]
In the case of a general passenger car tire having a cavity resonance frequency of 250 Hz, if the resonance frequency of the Helmholtz resonance sound absorber is in the range of 100 to 500 Hz, there is an effect of reducing the cavity resonance sound.
[0116]
In addition, according to the configuration of the current tire size, since the resonance frequency of each tire is in a range of approximately 180 to 300 Hz, it is more preferable to adjust each dimension so that the resonance frequency of the Helmholtz resonance sound absorber also falls within this range. It is preferable to obtain a large noise reduction effect.
[Second embodiment]
Next, a pneumatic run-flat tire 42 according to a second embodiment of the present invention will be described with reference to FIGS. The same components as those in the first embodiment are denoted by the same reference numerals, and description thereof will be omitted.
[0117]
As shown in FIGS. 5 and 6, the support 44 of the present embodiment includes the support 26, the leg 28, and a partition 37 described later.
[0118]
In the present embodiment, a space surrounded by the support 16 and the rim 12 is defined as a sub air chamber 34 and a tire air chamber 36 surrounded by the pneumatic tire 14 and the support 16.
[0119]
The sub air chamber 34 of the present embodiment is divided into a plurality of small sub air chambers 34A in the circumferential direction by a partition wall 46 formed of an elastic body such as a thick rubber.
[0120]
The partition wall 46 is adhered to the inner peripheral surface of the support 16.
[0121]
The inner peripheral edge of the partition wall 46 is pressed against the outer peripheral surface of the rim 12 together with the leg 28.
[0122]
Also in the pneumatic run flat tire 42, since the Helmholtz resonance sound absorber is constituted by the small auxiliary air chamber 34A and the communication hole 38, the same operation and effect as those of the pneumatic run flat tire 10 of the first embodiment are obtained. can get.
[0123]
In the pneumatic run-flat tire 42 according to the present embodiment, since the partition wall 46 is formed of an elastic body such as rubber, it can be elastically deformed together with the leg 28 at the time of puncturing to absorb a shock.
(Test example)
In order to confirm the effects of the present invention, one type of pneumatic tire of a comparative example (control product: a combination product of a conventional rim wheel and a tire) and two types of pneumatic run-flat tires of the example to which the present invention is applied Was prototyped, pressed against a drum simulating a normal road surface, and the tire noise when running at a constant speed was measured.
[0124]
In addition, in order to confirm the effect of the support, a passenger car equipped with the pneumatic tire of the comparative example and a passenger car equipped with the pneumatic run-flat tire of the example were subjected to a puncture durability test with the right front wheel air pressure set to 0. went.
[0125]
The running was performed at a speed of 90 km / h using a circuit having a straight line or a gentle curve.
[0126]
Comparative Example: A 185 / 60R14 size normal passenger car tire is mounted on a normal rim size 6JJ14 aluminum wheel.
[0127]
Tire air chamber volume is 35000cm ³ It is.
[0128]
Example 1: A pneumatic run-flat tire having the structure shown in the first embodiment (see FIG. 1), in which the tire and the wheel are the same as the comparative example.
[0129]
The total volume of the sub air chamber is 1200 cm ³ And 3.4% of the total volume of the tire air chamber (the total volume of the tire air chamber and the sub air chamber).
[0130]
Each small auxiliary air chamber was provided with one communicating hole having a diameter of 0.5 cm and a length of 0.2 cm, and the resonance frequency of the Helmholtz resonance sound absorber was set to 230 Hz.
[0131]
Example 2: A pneumatic run-flat tire having the structure shown in the second embodiment (see FIG. 5), in which the tire and the wheel are the same as the comparative example.
[0132]
Total volume of sub air chamber is 3000cm ³ Which is 8.6% of the total volume of the tire air chamber (the total volume of the tire air chamber and the sub air chamber).
[0133]
Each small auxiliary air chamber was provided with one communicating hole having a diameter of 1.0 cm and a length of 0.2 cm, and the resonance frequency of the Helmholtz resonance sound absorber was set to 240 Hz. .
[0134]
The internal pressure was set to 200 kPa in both the comparative example and Examples 1 and 2.
[0135]
In the test, when the pneumatic run flat tire was pressed against the drum with a load of 400 kgf and was run at a speed of 60 km / h, the axial force in the vertical direction of the drum was measured, and frequency analysis was performed. The drum used in the test had a diameter of 3 m, and asphalt imitating a general road shape was attached to the surface. This test is a test method for so-called road noise transmitted to the inside of a vehicle as vibration.
[0136]
Table 1 below shows the test results.
[0137]
[Table 1]

As a result of the test, it was confirmed that the pneumatic run-flat tires of Examples 1 and 2 had significantly reduced cavity resonance sound as compared with the pneumatic tire of the comparative example.
[0138]
In addition, it can be seen that the pneumatic run-flat tires of Examples 1 and 2 have a long running distance up to the failure and have greatly improved durability.
[0139]
【The invention's effect】
As described above, since the support according to claim 1 of the present invention has the above-described configuration, the support is mounted together with the pneumatic tire on a general-purpose rim to form a pneumatic run-flat tire capable of reducing noise. Has an excellent effect that
[0140]
Since the support according to claim 2 is configured as described above, an excellent effect that a pneumatic run-flat tire capable of reducing noise can be configured by mounting the support on a general-purpose rim together with a pneumatic tire. Having.
[0141]
Since the support according to claim 3 is configured as described above, the resonance frequency can be shifted by changing the volume of the divided sub-air chamber and the dimensions of the communication portion, and can be shifted over a wide frequency range. It has an excellent effect that noise can be reduced.
[0142]
Since the support according to claim 4 has the above-described configuration, it has an excellent effect that noise at 100 to 500 Hz can be reduced.
[0143]
Since the support according to claim 5 has the above-described configuration, the pneumatic tire does not contact the support during normal running, and the effect of reducing cavity resonance can be reliably obtained.
[0144]
The pneumatic run-flat tire according to claim 6 has the above-described configuration, and thus has an excellent effect that tire noise can be reduced using a general-purpose rim and a pneumatic tire.
[Brief description of the drawings]
FIG. 1 is a perspective view showing a cross section of a part of a pneumatic run flat tire according to a first embodiment of the present invention.
FIG. 2 is a cross-sectional view of the pneumatic run-flat tire according to the first embodiment, which is perpendicular to the axis.
FIG. 3 is a cross-sectional view perpendicular to an axis of a support used in the pneumatic run-flat tire according to the first embodiment.
FIG. 4 is a cross-sectional view of a pneumatic run-flat tire when the internal pressure is zero.
FIG. 5 is a perspective view showing a cross section of a part of a pneumatic run flat tire according to a second embodiment of the present invention.
FIG. 6 is a cross-sectional view perpendicular to an axis of a support used for a pneumatic run-flat tire according to a second embodiment.
[Explanation of symbols]
10 Pneumatic run flat tire
12 Rim
14 Pneumatic tire
16 Support
24 tread section
26 Support
28 legs
32 lid member (sub air chamber forming member)
34 Secondary air chamber
34A Small auxiliary air chamber
36 Tire Chamber
37 Partition
38 Communication hole (communication part)
42 Pneumatic runflat tire
44 Support
46 Partition

Claims (6)

An annular support that is disposed inside the pneumatic tire and is attached to the rim together with the pneumatic tire, and is capable of supporting a load during run flat running,
In the radial cross section of the support, a curved portion including two convex portions protruding outward in the radial direction and side portions extending radially inward in the width direction outside than the radially outermost positions of the convex portions. A linear support portion, an elastic body integrated with the radially inner end of the side portion, a leg mounted on the rim when assembling the rim, and a sub-portion discontinuous with at least the support portion; A sub air chamber forming member that forms an air chamber, and a tire air chamber that is provided on at least one of the support portion and the leg portion and that is formed between the tire inner surface and the rim with at least the tire inner surface as a part of a partition wall. A communication unit for communicating the sub air chamber with the communication unit,
The support body, wherein the sub air chamber and the communication portion function as a Helmholtz resonance sound absorber. An annular support that is disposed inside the pneumatic tire and is attached to the rim together with the pneumatic tire, and is capable of supporting a load during run flat running,
In the radial cross section of the support, a curved portion including two convex portions protruding outward in the radial direction and side portions extending radially inward in the width direction outside than the radially outermost positions of the convex portions. A linear support portion, an elastic body integrated with a radially inner end of the side portion, a leg portion mounted on the rim when the rim is assembled, and the leg portion mounted on the rim. A sub-air chamber forming member formed of an elastic body that forms a sub-air chamber that is discontinuous in the circumferential direction between the support portion, the leg portion, and the rim, and is provided on at least one of the support portion and the leg portion. A communication portion that communicates the auxiliary air chamber to a tire air chamber formed between the tire inner surface and the rim as at least a part of the inner wall of the tire as a partition,
The support body, wherein the sub air chamber and the communication portion function as a Helmholtz resonance sound absorber. The support according to claim 1 or 2, further comprising a plurality of partition walls that partition the sub air chamber into a plurality of sections. The resonance frequency of the Helmholtz resonance sound absorber composed of the sub air chamber and the communication portion is set in a range of 100 to 500 Hz. The support according to 1. The total volume of the sub air chamber is 2% or more and 50% or less of the total volume of the tire air chamber combined with the tire air chamber and the sub air chamber. The support according to claim 1. A carcass formed in a toroidal shape between a pair of bead cores, a side rubber layer arranged outside the carcass in the tire axial direction to constitute a tire side portion, and a tread portion arranged outside the carcass in a tire radial direction to constitute a tread portion A tread rubber layer, and a tire mounted on the rim,
The support according to any one of claims 1 to 5, wherein the support is disposed inside the tire, and is attached to a rim together with the tire.
A pneumatic run-flat tire comprising:

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