JP2009029259A - Pneumatic tire - Google Patents

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JP2009029259A
JP2009029259A JP2007195030A JP2007195030A JP2009029259A JP 2009029259 A JP2009029259 A JP 2009029259A JP 2007195030 A JP2007195030 A JP 2007195030A JP 2007195030 A JP2007195030 A JP 2007195030A JP 2009029259 A JP2009029259 A JP 2009029259A
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Prior art keywords
branch groove
groove
branch
air chamber
circumferential
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Osamu Fujiwara
修 藤原
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Bridgestone Corp
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Bridgestone Corp
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Abstract

<P>PROBLEM TO BE SOLVED: To provide a pneumatic tire reducing columnar resonance sound caused by a circumferential groove at a wide frequency band area. <P>SOLUTION: The pneumatic tire is provided with: at least one circumferential groove extending along a tread circumferential line; and a branch groove separated/extended from the circumferential group on a tread surface of a tire. In the branch groove, a plurality of arrangements where a branch groove part and an air chamber part having a larger cross section than a cross section of the branch groove part are aligned in the order from the circumferential groove side, are continued. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

本発明は、タイヤの騒音を低減した空気入りタイヤ、特にトレッド踏面に形成した周方向溝に起因した気柱共鳴音を低減した空気入りタイヤに関するものである。   The present invention relates to a pneumatic tire with reduced tire noise, and more particularly to a pneumatic tire with reduced air column resonance caused by circumferential grooves formed on a tread surface.

近年の車両の静粛化に伴って、自動車騒音における、タイヤ騒音の占める割合が相対的に大きくなっているため、そのタイヤ騒音の低減が大きな課題となっている。なかでも、1000Hz前後のタイヤ騒音は車外騒音の主な要因となっており、この騒音は、環境問題の点からも早急な対策が望まれている。   With the recent quietness of vehicles, the proportion of tire noise in automobile noise has become relatively large, so reducing tire noise has become a major issue. Among these, tire noise around 1000 Hz is a major factor of noise outside the vehicle, and an immediate countermeasure is desired for this noise from the viewpoint of environmental problems.

ところで、一般的な乗用車において、800〜1200Hzの周波数帯域に属するタイヤ騒音は、タイヤの接地面内で、トレッドに形成した周方向溝と路面とによって区画される気柱が共鳴すること、いわゆる気柱共鳴によって発生することが一般に知られている。
すなわち、周方向溝を有するタイヤが接地した状態において、該周方向溝の溝壁と、接地面との間に接地長と同じ長さの管が形成され、タイヤの走行に伴い、気柱共鳴音と呼ばれるノイズが発生する。この気柱共鳴音の周波数fは、音速をcとし、管の長さ、すなわち、周方向溝の長さに開口端補正量を足したものをLとすると、
=c/2L
で表わされる一定の周波数である。なお、開口端補正量とは、通常は実験によって求められるものであり、管が円筒形の場合、管の内側の半径に定数を乗じたものとなる。
By the way, in a general passenger car, tire noise belonging to the frequency band of 800 to 1200 Hz is caused by resonance of air columns defined by circumferential grooves formed in a tread and a road surface within a tire contact surface, so-called air pressure. It is generally known that it occurs due to column resonance.
In other words, when a tire having a circumferential groove is in contact with the ground, a tube having the same length as the contact length is formed between the groove wall of the circumferential groove and the contact surface. Noise called sound is generated. The frequency f 0 of the air column resonance sound is defined as L, where the speed of sound is c, the length of the tube, that is, the length of the circumferential groove and the opening end correction amount is added.
f 0 = c / 2L
It is a constant frequency represented by The opening end correction amount is normally obtained by experiment, and when the tube is cylindrical, it is obtained by multiplying the radius inside the tube by a constant.

この気柱共鳴音は高いピークを有し、周波数帯域も広いため、騒音の中でもタイヤ起因の直接音となる主要な要因のひとつである。また、人間の聴覚は、人間の聴覚感度特性を反映したA特性と呼ばれる周波数補正特性で示されるように、1000Hz前後の周波数帯域で敏感であり、フィーリング面の静粛性を向上させる意味でもこの気柱共鳴音を低減することが望ましい。   This air column resonance sound has a high peak and a wide frequency band, and is one of the main factors that cause a direct sound due to tires among noises. In addition, human hearing is sensitive in a frequency band around 1000 Hz, as shown by a frequency correction characteristic called A characteristic that reflects human auditory sensitivity characteristics, and this also means that the quietness of the feeling surface is improved. It is desirable to reduce air column resonance.

このような気柱共鳴の抑制のために、特許文献1には、トレッドに、その周方向に直線状もしくはジグザグ状に連続する2本以上の周方向溝を設け、少なくとも1本の周方向溝に付き、一端がその周方向溝に開口し、他端が陸部内で終了する複数本の分岐溝を形成し、それぞれの分岐溝を、接地面内に常に1本以上が完全に含まれる配設態様とした、サイドブランチ型共鳴器を有するトレッドパターンが提案されている。   In order to suppress such air column resonance, in Patent Document 1, the tread is provided with two or more circumferential grooves continuous linearly or zigzag in the circumferential direction, and at least one circumferential groove is provided. And a plurality of branch grooves are formed with one end opening in the circumferential groove and the other end ending in the land. Each branch groove is always included in the ground plane so that at least one branch groove is completely included. There has been proposed a tread pattern having a side branch type resonator as an embodiment.

このように、周方向溝から枝分かれした分岐溝を設けることにより、気柱共鳴音の周波数を分散させることができる。この周波数の分散効果は、分岐溝の形状により変わる。具体的には、分岐溝の長さに開口端補正量を足したものをL、音速をcとすると、減音周波数fは、

Figure 2009029259
n:振動次数(n=1,3,5・・・)
で表されることがわかっている。 As described above, by providing the branch groove branched from the circumferential groove, the frequency of the air column resonance sound can be dispersed. This frequency dispersion effect varies depending on the shape of the branch groove. Specifically, if the length of the branch groove plus the opening end correction amount is L, and the sound speed is c, the sound reduction frequency f is
Figure 2009029259
n: vibration order (n = 1, 3, 5...)
It is known that

また、特許文献2には、この分岐溝を断面積が小さい枝溝部と断面積が大きい気室部とからなる、いわゆるヘルムホルツ共鳴器とすることによって気柱共鳴音を低減することが、提案されている。
この場合、音速をc、枝溝部の長さに開口端補正量を足したものをL、枝溝部の断面積をS、気室部の体積をVとすると、減音周波数fは、

Figure 2009029259
で表されることが分かっている。 Further, Patent Document 2 proposes to reduce the air column resonance sound by using a so-called Helmholtz resonator that includes a branch groove portion having a small cross-sectional area and an air chamber portion having a large cross-sectional area. ing.
In this case, if the sound velocity is c, the length of the branch groove portion plus the opening end correction amount is L, the sectional area of the branch groove portion is S, and the volume of the air chamber portion is V, the sound reduction frequency f is
Figure 2009029259
It is known that

あるいは、上述したようなヘルムホルツ型の共鳴器に代えて、図1に示すように、それぞれ、その長さ方向に一定の断面積S、Sを有する断面積の異なる管路を連結した段付き管型の共鳴器を適用することもできる。この場合には、それぞれの管路の長さに開口端補正量を足したものをL、L、音速をcとすると、共鳴周波数fは、

Figure 2009029259
Figure 2009029259
で表されることが分かっている。 Alternatively, instead of the Helmholtz type resonator as described above, as shown in FIG. 1, stages in which pipes having different cross-sectional areas having constant cross-sectional areas S 1 and S 2 are connected in the length direction, respectively. A tube-type resonator can also be applied. In this case, when L 1 and L 2 are obtained by adding the opening end correction amount to the length of each pipe line and the sound speed is c, the resonance frequency f is given by
Figure 2009029259
Figure 2009029259
It is known that

国際公開第2004/103737号パンフレットInternational Publication No. 2004/1037737 Pamphlet 特開平5−338411号公報Japanese Patent Laid-Open No. 5-338411

上述した共鳴器による気柱共鳴音の減音効果は、共鳴器の共鳴周波数では非常に大きいが、それ以外の周波数帯域ではほとんどみられない。それゆえ、幅広い周波数帯域での減音を所期したとき、周方向溝に起因した気柱共鳴音の低減は未だ不十分であった。   The above-described sound column resonance reduction effect by the resonator is very large at the resonance frequency of the resonator, but is hardly observed in other frequency bands. Therefore, when sound reduction in a wide frequency band is expected, the reduction of the air column resonance due to the circumferential groove is still insufficient.

そこで、本発明の目的は、上述した問題点を解消して、幅広い周波数帯域の気柱共鳴音の低減を達成する空気入りタイヤを提供することにある。   Therefore, an object of the present invention is to provide a pneumatic tire that solves the above-described problems and achieves reduction of air column resonance noise in a wide frequency band.

本発明の要旨は、以下のとおりである。
(1)タイヤのトレッド踏面に、トレッド周線に沿って延びる少なくとも1本の周方向溝と、該周方向溝から分かれて延びる分岐溝とを具える空気入りタイヤにおいて、
前記分岐溝は、前記周方向溝側から順に、枝溝部と該枝溝部の断面積より大きい断面積を有する気室部とが並ぶ配列を複数連ねてなる、
ことを特徴とする空気入りタイヤ。
The gist of the present invention is as follows.
(1) In a pneumatic tire comprising, on a tread surface of a tire, at least one circumferential groove extending along a tread circumferential line and a branch groove extending from the circumferential groove,
The branch groove is formed by connecting a plurality of arrays in which a branch groove portion and an air chamber portion having a cross-sectional area larger than the cross-sectional area of the branch groove portion are arranged in order from the circumferential groove side.
A pneumatic tire characterized by that.

ここで、トレッド踏面とは、タイヤを適用リムに装着するとともに、それに最高空気圧を充填して平板上に垂直に置き、そこへ最大負荷能力に相当する質量を負荷したときに平板と接触することになるトレッドゴムの表面領域をいうものとする。
また、枝溝部および気室部の断面積とは、枝溝部および気室部が直線的に延びている場合、管や室を区画する側壁に垂直な向きに枝溝部および気室部を切断した面の面積であり、枝溝部および気室部が曲線状に延びている場合、枝溝部および気室部それぞれの延在長さの中間点における側壁に対する法線で枝溝部および気室部を切断した面の面積のことである。
Here, the tread tread means that the tire is mounted on the applicable rim, filled with the highest air pressure, placed vertically on the flat plate, and brought into contact with the flat plate when a mass corresponding to the maximum load capacity is loaded thereon. The surface area of the tread rubber.
In addition, the cross-sectional area of the branch groove portion and the air chamber portion means that when the branch groove portion and the air chamber portion extend linearly, the branch groove portion and the air chamber portion are cut in a direction perpendicular to the side wall that divides the tube and the chamber. When the branch groove part and air chamber part extend in a curved shape, the branch groove part and air chamber part are cut along the normal to the side wall at the midpoint of the extension length of each branch groove part and air chamber part. It is the area of the finished surface.

(2)前記枝溝部の断面積は、前記周方向溝側に位置する枝溝部が大きい上記(1)に記載の空気入りタイヤ。 (2) The pneumatic tire according to (1), wherein a cross-sectional area of the branch groove portion is larger in a branch groove portion located on the circumferential groove side.

(3)前記気室部の体積は、前記周方向溝側に位置する気室部が大きい上記(1)または(2)に記載の空気入りタイヤ。 (3) The pneumatic tire according to (1) or (2), wherein the volume of the air chamber portion is larger in the air chamber portion located on the circumferential groove side.

本発明によれば、周方向溝から枝分かれさせた分岐溝に、ヘルムホルツ共鳴器を複数連ねた機能を持たせられるから、幅広い周波数帯域の気柱共鳴音の低減を達成する空気入りタイヤを提供することができる。   According to the present invention, a pneumatic tire that achieves a reduction in air column resonance noise in a wide frequency band can be provided because the branch groove branched from the circumferential groove has a function of connecting a plurality of Helmholtz resonators. be able to.

以下に、本発明の空気入りタイヤの実施形態を、図面を参照して詳しく説明する。
なお、タイヤの内部補強構造等は一般的なラジアルタイヤのそれと同様であるので図示を省略する。
Hereinafter, embodiments of the pneumatic tire of the present invention will be described in detail with reference to the drawings.
In addition, since the internal reinforcement structure of a tire is the same as that of a general radial tire, illustration is omitted.

図2は本発明の空気入りタイヤの一実施形態を示すトレッドパターンの展開図である。本実施形態の空気入りタイヤのトレッド踏面1には、タイヤ周方向に連続して延びる複数本の周方向溝2と、それら周方向溝2のうちトレッド中央部に配置した2本の周方向溝2から分かれて延びる分岐溝3とを設けている。
なお、図2においてはトレッド中央部に配置した2本の周方向溝2に分岐溝3を設けているが、その他の周方向溝2に分岐溝3を設けてもよく、1本の周方向溝2からその両側に向かう分岐溝3を設けてもよい。なお、分岐溝3を全ての周方向溝に対して設ける場合が最も好ましい。
FIG. 2 is a development view of a tread pattern showing an embodiment of the pneumatic tire of the present invention. The tread surface 1 of the pneumatic tire according to the present embodiment includes a plurality of circumferential grooves 2 continuously extending in the tire circumferential direction, and two circumferential grooves disposed in the center of the tread among the circumferential grooves 2. 2 and a branching groove 3 extending separately.
In FIG. 2, the branch grooves 3 are provided in the two circumferential grooves 2 disposed in the center of the tread. However, the branch grooves 3 may be provided in the other circumferential grooves 2. You may provide the branched groove | channel 3 which goes to the both sides from the groove | channel 2. FIG. It is most preferable that the branch grooves 3 are provided for all the circumferential grooves.

分岐溝3は、図示例において、周方向溝2に直接開口する第1枝溝部3a−1と、第1枝溝部3a−1に接続し第1枝溝部3a−1よりも断面積が大きい第1気室部3b−1と、第1気室部3b−1に連なる第2枝溝部3a−2と、第2枝溝部3a−2に接続し第2枝溝部3a−2よりも断面積が大きい第2気室部3b−2とからなる。ここで、第1枝溝部3a−1の断面積は、図2のA−A線に沿う断面積であり、第1気室部3b−1の断面積は、図2のB−B線に沿う断面積であり、第2枝溝部3a−2の断面積は、図2のC−C線に沿う断面積であり、第2気室部3b−2の断面積は、図2のD−D線に沿う断面積である。なお、枝溝部および気室部の断面積は、枝溝部および気室部が曲線状に延びているので、枝溝部および気室部それぞれの延在長さの中間点における側壁に対する法線で枝溝部および気室部を切断した面の面積のことである。   In the illustrated example, the branch groove 3 includes a first branch groove portion 3a-1 that directly opens in the circumferential groove 2, and a first cross groove area that is connected to the first branch groove portion 3a-1 and has a larger cross-sectional area than the first branch groove portion 3a-1. 1 air chamber portion 3b-1, a second branch groove portion 3a-2 connected to the first air chamber portion 3b-1, and a cross-sectional area connected to the second branch groove portion 3a-2 and larger than that of the second branch groove portion 3a-2. It consists of a large second air chamber 3b-2. Here, the cross-sectional area of the first branch groove portion 3a-1 is a cross-sectional area along the line AA in FIG. 2, and the cross-sectional area of the first air chamber portion 3b-1 is the line BB in FIG. 2, the cross-sectional area of the second branch groove portion 3 a-2 is a cross-sectional area along the line CC of FIG. 2, and the cross-sectional area of the second air chamber portion 3 b-2 is D- It is a cross-sectional area along the D line. Note that the cross-sectional areas of the branch groove portion and the air chamber portion are branched by a normal line to the side wall at the midpoint of the extending length of each of the branch groove portion and the air chamber portion because the branch groove portion and the air chamber portion extend in a curved line. It is the area of the surface which cut | disconnected the groove part and the air chamber part.

また、図2(b)に示すように、枝溝部と気室部は、気室部の枝溝幅に対して拡大する溝壁(拡大溝壁)を延長させた線によって区分けすることができる。すなわち、第1枝溝部と第1気室部は、第1枝溝部に接する第1気室部の拡大溝壁を延長させた線lによって区分けし、第1気室部と第2枝溝部は、第2枝溝部に接する第1気室部の拡大溝壁を延長させた線lによって区分けし、第2枝溝部と第2気室部は、第2枝溝部に接する第2気室部の拡大溝壁を延長させた線lによって区分けする。 Further, as shown in FIG. 2B, the branch groove portion and the air chamber portion can be divided by a line obtained by extending a groove wall (enlarged groove wall) that expands with respect to the branch groove width of the air chamber portion. . That is, the first branch groove and the first air chamber section, an enlarged groove wall of the first air chamber portion in contact with the first branch groove is divided by the line l 1 that is extended, and a second branch groove first air chamber is an enlarged groove wall of the first air chamber which is in contact with the second branch groove is divided by a line l 2 which is extended, the second branch groove and the second air chamber section, a second air chamber in contact with the second branch groove the expansion groove wall parts partitioning by a line l 3 which is extended.

ここで、周方向溝2から分岐させた分岐溝3は、第1枝溝部3a−1および第1気室部3b−1並びに第2枝溝部3a−2および第2気室部3b−2といった、枝溝部と気室部との組み合わせによるヘルムホルツ共鳴器を分岐溝3の延長方向に、複数直列に接続することが肝要である。なお、図2の例では2つのヘルムホルツ共鳴器を設けたが、図3(a)に示すように3つのヘルムホルツ共鳴器を設けて、分岐溝3を第1枝溝部3a−1、第1気室部3b−1、第2枝溝部3a−2、第2気室部3b−2、第3枝溝部3a−3、および第3気室部3b−3から構成してもよい。また、図3(a)に示したように、枝溝部が同じ向きで直線状に並ぶ配置に限定されることはなく、例えば、図3(b)に示すように、第1枝溝部3a−1と第2枝溝部3a−2とを直角に配置する、あるいは、図3(c)に示すように、第1枝溝部3a−1と第2枝溝部3a−2と逆向きに配置してもよい。   Here, the branch groove 3 branched from the circumferential groove 2 is a first branch groove portion 3a-1, a first air chamber portion 3b-1, a second branch groove portion 3a-2, and a second air chamber portion 3b-2. It is important to connect a plurality of Helmholtz resonators in combination with the branch groove part and the air chamber part in the extension direction of the branch groove 3 in series. In the example of FIG. 2, two Helmholtz resonators are provided. However, as shown in FIG. 3A, three Helmholtz resonators are provided, and the branch groove 3 is formed as the first branch groove portion 3 a-1 and the first air groove. You may comprise from chamber part 3b-1, 2nd branch groove part 3a-2, 2nd air chamber part 3b-2, 3rd branch groove part 3a-3, and 3rd air chamber part 3b-3. Further, as shown in FIG. 3 (a), the branch groove portions are not limited to the linear arrangement in the same direction. For example, as shown in FIG. 3 (b), the first branch groove portions 3a- 1 and the second branch groove part 3a-2 are arranged at right angles, or as shown in FIG. 3C, the first branch groove part 3a-1 and the second branch groove part 3a-2 are arranged in opposite directions. Also good.

さて、上述したように、ヘルムホルツ共鳴器はその共鳴周波数付近の音しか低減せず、それ以外の周波数帯域の音はほとんど低減できない。そこで、幅広い周波数帯域において音圧レベルの低減効果を得るために、共鳴周波数が異なる複数種の共鳴器、すなわち大きさの異なるヘルムホルツ共鳴器が同時に接地面内に入るようにトレッドパターンを設計することが有効であると考えられる。しかし、複数種の共鳴器を同一周方向溝に接続させて配置するには、通常トレッド周方向長さが100mm〜200mm程度のタイヤ接地面内に複数種の共鳴器を収めることになり、トレッドパターンのデザイン上大きな制約を設けなければならないことになる。
そこで、本発明者が鋭意検討を重ねた結果、周方向溝から枝分かれさせた分岐溝を、周方向溝側から順に、枝溝部と該枝溝部の断面積より大きい断面積を有する気室部とが並ぶ配列を複数連ねてなる、ヘルムホルツ共鳴器を複数連結させた形状とすることにより、周方向溝に起因する気柱共鳴音の周波数近傍で少なくとも2つの共鳴周波数を持たせることが可能であり、幅広い周波数帯域で音圧レベルを低減できることを知見した。これにより、共鳴周波数が異なる複数種の共鳴器を周方向溝に個別に接続させて配置し、これらの複数種の共鳴器が同時に接地面内に入るようにトレッドパターンを設計する場合と同等以上の騒音低減効果が、トレッドパターンのデザイン自由度を阻害することなく得られる。
As described above, the Helmholtz resonator reduces only the sound near the resonance frequency, and hardly reduces the sound in other frequency bands. Therefore, in order to obtain a sound pressure level reduction effect in a wide frequency band, the tread pattern should be designed so that multiple types of resonators with different resonance frequencies, that is, Helmholtz resonators with different sizes, enter the ground plane at the same time. Is considered effective. However, in order to place a plurality of types of resonators connected to the same circumferential groove, a plurality of types of resonators are usually housed in a tire contact surface having a tread circumferential length of about 100 mm to 200 mm. It will be necessary to place a great restriction on the design of the pattern.
Therefore, as a result of repeated studies by the inventor, the branch groove branched from the circumferential groove has, in order from the circumferential groove side, a branch groove portion and an air chamber portion having a cross-sectional area larger than the cross-sectional area of the branch groove portion. It is possible to have at least two resonance frequencies in the vicinity of the frequency of the air column resonance sound caused by the circumferential groove by forming a shape in which a plurality of Helmholtz resonators connected to each other are arranged in series. It has been found that the sound pressure level can be reduced in a wide frequency band. This is equivalent to or more than when tread patterns are designed so that multiple types of resonators with different resonance frequencies are individually connected to the circumferential groove and these multiple types of resonators enter the ground plane at the same time. The noise reduction effect can be obtained without hindering the design freedom of the tread pattern.

次に、図4(a)〜(c)を用いて分岐溝の詳細をより具体的に説明する。
図4(a)に示すように、分岐溝3は、周方向溝2に接続した第1枝溝部3a−1の断面積が、第2枝溝部3a−2の断面積より大きく、かつ、第1気室部3b−1の体積が第2気室部3b−2の体積より大きいことが好ましい。なぜなら、周方向溝2に起因する気柱共鳴音の周波数近傍で、分岐溝3による共鳴器の共鳴周波数を2つ持たせるためには、断面積および体積をそれぞれ変える必要があるからである。
したがって、枝溝部および気室部の組み合わせが3組以上の場合も、枝溝部の断面積は、周方向溝に接続した枝溝部の断面積が一番大きく、周方向溝から離れる方向に小さくなり、気室部の体積は、周方向溝に接続した枝溝部につながる気室部の体積が一番大きく、周方向溝から離れる方向に小さくなる。
また、図4(b)に示すように、第1枝溝部3a−1と第2枝溝部3a−2の断面積が等しく、第1気室部3b−1と第2気室部3b−2の体積が等しい場合、あるいは、図4(c)に示すように、第1枝溝部3a−1の断面積が、第2枝溝部3a−2の断面積より小さく、かつ、第1気室部3b−1の体積が第2気室部3b−2の体積より小さい場合も、騒音の低減効果が得られる。
Next, the details of the branch groove will be described more specifically with reference to FIGS.
As shown in FIG. 4A, the branch groove 3 has a cross-sectional area of the first branch groove part 3a-1 connected to the circumferential groove 2 larger than that of the second branch groove part 3a-2, and The volume of the first air chamber portion 3b-1 is preferably larger than the volume of the second air chamber portion 3b-2. This is because in order to have two resonance frequencies of the resonator formed by the branch groove 3 in the vicinity of the frequency of the air column resonance sound caused by the circumferential groove 2, it is necessary to change the cross-sectional area and the volume, respectively.
Therefore, even when there are three or more combinations of branch groove portions and air chamber portions, the cross sectional area of the branch groove portion is the largest in the cross sectional area of the branch groove portion connected to the circumferential groove and decreases in the direction away from the circumferential groove. The volume of the air chamber part is the largest in the air chamber part connected to the branch groove part connected to the circumferential groove, and decreases in the direction away from the circumferential groove.
Further, as shown in FIG. 4B, the first branch chamber portion 3a-1 and the second branch groove portion 3a-2 have the same cross-sectional area, and the first air chamber portion 3b-1 and the second air chamber portion 3b-2. Or the first branch chamber portion 3a-1 has a smaller cross-sectional area than the second branch groove portion 3a-2 and the first air chamber portion, as shown in FIG. 4 (c). Also when the volume of 3b-1 is smaller than the volume of the 2nd air chamber part 3b-2, the noise reduction effect is acquired.

次に、本発明に係る空気入りタイヤ、基準タイヤおよび従来例タイヤを試作し性能評価を行ったので以下に説明する。
上述したとおり、図2は、発明例タイヤのトレッドパターンの展開図を示し、図5は基準タイヤのトレッドパターンの展開図を示し、図6は従来例タイヤのトレッドパターンの展開図を示す。
図2に示す発明例タイヤの分岐溝3は、断面積8mm、長さ18.2mmの第1枝溝部3a−1と、体積1600mmの第1気室部3b−1と、断面積1mm、長さ19.4mmの第2枝溝部3a−2と、体積300mmの第2気室部3b−2とからなる。この分岐溝3による共鳴周波数は652Hzと990Hzである。
一方、図5に示す基準タイヤの分岐溝3Mは、断面積4mm、長さ10.0mmの枝溝部と、体積1000mmの気室部とからなり、上述の数2式より求まる共鳴周波数は1010Hzである。
また、図6に示す従来例タイヤは、枝溝部および気室部の異なる2種類のヘルムホルツ共鳴器である分岐溝3N1、3N2を周方向溝に交互に設けた構成であり、分岐溝3N1は、断面積3mm、長さ17.6mmの枝溝部と、体積1100mmの気室部とからなり、共鳴周波数は651Hzとなり、分岐溝3N2は、断面積5mm、長さ17.4mmの枝溝部と、体積850mmの気室部とからなり、共鳴周波数は950Hzとなる。
Next, a pneumatic tire, a reference tire, and a conventional tire according to the present invention were prototyped and performance evaluation was performed, which will be described below.
As described above, FIG. 2 shows a development view of the tread pattern of the inventive tire, FIG. 5 shows a development view of the tread pattern of the reference tire, and FIG. 6 shows a development view of the tread pattern of the conventional tire.
The branch groove 3 of the example tire shown in FIG. 2 includes a first branch groove portion 3a-1 having a cross-sectional area of 8 mm 2 and a length of 18.2 mm, a first air chamber portion 3b-1 having a volume of 1600 mm 3 and a cross-sectional area of 1 mm. 2 and a second branch groove portion 3a-2 having a length of 19.4 mm and a second air chamber portion 3b-2 having a volume of 300 mm 3 . The resonance frequencies of the branch groove 3 are 652 Hz and 990 Hz.
On the other hand, the branch groove 3M of the reference tire shown in FIG. 5 includes a branch groove portion having a cross-sectional area of 4 mm 2 and a length of 10.0 mm and an air chamber portion having a volume of 1000 mm 3. 1010 Hz.
Further, the conventional tire shown in FIG. 6 has a configuration in which branch grooves 3N1 and 3N2, which are two types of Helmholtz resonators having different branch groove portions and air chamber portions, are alternately provided in the circumferential groove. It consists of a branch groove part with a cross-sectional area of 3 mm 2 and a length of 17.6 mm and an air chamber part with a volume of 1100 mm 3 , a resonance frequency of 651 Hz, and the branch groove 3N2 has a cross-sectional area of 5 mm 2 and a length of 17.4 mm. And an air chamber having a volume of 850 mm 3 , and the resonance frequency is 950 Hz.

発明例タイヤ、基準タイヤおよび従来例タイヤは、タイヤサイズがともに195/65R15である。これらのタイヤを15×6Jのリムに組み付けてタイヤ車輪とし、タイヤ内圧を210kPaに調整した。そして、荷重4kNを適用し、80km/hにて室内ドラム試験機で走行させた際のタイヤ側方音を、JASO C606規格にて定める条件で測定し、1/3オクターブバンド分析によって各帯域を評価した。また、気柱管共鳴帯域の総合的な評価として、1/3オクターブ中心周波数800−1000−1250Hz帯域のパーシャルオーバーオール値を用いた。   The tire sizes of the inventive example tire, the reference tire, and the conventional example tire are both 195 / 65R15. These tires were assembled on a 15 × 6J rim to form tire wheels, and the tire internal pressure was adjusted to 210 kPa. The tire side sound when running with an indoor drum tester at 80 km / h with a load of 4 kN was measured under the conditions defined in the JASO C606 standard, and each band was measured by 1/3 octave band analysis. evaluated. Further, as a comprehensive evaluation of the air column resonance band, a partial overall value of a 1/3 octave center frequency 800-1000-1250 Hz band was used.

基準タイヤ対比の総合的な減音効果としては、従来例タイヤでは2.4dB、発明例タイヤでは3.0dBであった。発明例タイヤでは、従来例タイヤの場合に比べて、より狭い周方向幅内で2つの周波数における減音効果が得られているため、分岐溝3が共鳴器として作用する時間が長く(踏面内に存在する時間が長く)、大きな減音効果が得られたものと考えられる。   The overall sound reduction effect compared with the reference tire was 2.4 dB for the conventional tire and 3.0 dB for the inventive tire. In the tire of the invention, since the sound reduction effect at two frequencies is obtained within a narrower circumferential width than in the case of the conventional tire, the time for the branch groove 3 to act as a resonator is long (inside the tread) It is considered that a great sound reduction effect was obtained.

以上により、2つのヘルムホルツ共鳴器を連結させた分岐溝を周方向溝に設けることによって、トレッドパターンのデザイン自由度を阻害することなく、幅広い周波数帯域の気柱共鳴音の低減を高次元で達成されたことが分かる。   As described above, by providing a branch groove connecting two Helmholtz resonators in the circumferential groove, a reduction in air column resonance noise in a wide frequency band can be achieved at a high level without impairing the design freedom of the tread pattern. You can see that

段付き管型の共鳴器を模式的に示す図である。It is a figure which shows a stepped tube type resonator typically. 発明例タイヤのトレッドパターンの展開図を示す。The development view of the tread pattern of the tire of the inventive example is shown. (a)〜(c)は、分岐溝の構成例示す。(A)-(c) shows the structural example of a branch groove | channel. (a)〜(c)は、分岐溝の構成例を具体的に示す。(A)-(c) shows the example of composition of a branching groove concretely. 基準タイヤのトレッドパターンの展開図を示す。The development view of the tread pattern of the reference tire is shown. 従来例タイヤのトレッドパターンの展開図を示す。The development view of the tread pattern of the conventional tire is shown.

符号の説明Explanation of symbols

1 トレッド踏面
2 周方向溝
3、3M、3N1、3N2 分岐溝
3a−1 第1枝溝部
3a−2 第2枝溝部
3a−3 第3枝溝部
3b−1 第1気室部
3b−2 第2気室部
3b−3 第3気室部
1 tread surface 2 circumferential groove 3, 3M, 3N1, 3N2 branch groove 3a-1 first branch groove portion 3a-2 second branch groove portion 3a-3 third branch groove portion 3b-1 first air chamber portion 3b-2 second Air chamber 3b-3 Third air chamber

Claims (3)

タイヤのトレッド踏面に、トレッド周線に沿って延びる少なくとも1本の周方向溝と、該周方向溝から分かれて延びる分岐溝とを具える空気入りタイヤにおいて、
前記分岐溝は、前記周方向溝側から順に、枝溝部と該枝溝部の断面積より大きい断面積を有する気室部とが並ぶ配列を複数連ねてなる、
ことを特徴とする空気入りタイヤ。
In a pneumatic tire comprising at least one circumferential groove extending along a tread circumferential line and a branch groove extending from the circumferential groove on a tread surface of the tire,
The branch groove is formed by connecting a plurality of arrays in which a branch groove portion and an air chamber portion having a cross-sectional area larger than the cross-sectional area of the branch groove portion are arranged in order from the circumferential groove side.
A pneumatic tire characterized by that.
前記枝溝部の断面積は、前記周方向溝側に位置する枝溝部が大きい請求項1に記載の空気入りタイヤ。   2. The pneumatic tire according to claim 1, wherein a cross-sectional area of the branch groove portion is larger in a branch groove portion located on the circumferential groove side. 前記気室部の体積は、前記周方向溝側に位置する気室部が大きい請求項1または2に記載の空気入りタイヤ。   The pneumatic tire according to claim 1 or 2, wherein a volume of the air chamber portion is larger in an air chamber portion located on the circumferential groove side.
JP2007195030A 2007-07-26 2007-07-26 Pneumatic tire Withdrawn JP2009029259A (en)

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Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP4521473B1 (en) * 2009-05-29 2010-08-11 株式会社ブリヂストン tire
JP2010260413A (en) * 2009-04-30 2010-11-18 Bridgestone Corp Tire
US20130263984A1 (en) * 2010-10-14 2013-10-10 Michelin Recherche Et Technique S.A. Noise attenuator devices for tires
CN112606629A (en) * 2020-12-28 2021-04-06 合肥工业大学 Wide band low noise pneumatic tire tread pattern

Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2010260413A (en) * 2009-04-30 2010-11-18 Bridgestone Corp Tire
JP4521473B1 (en) * 2009-05-29 2010-08-11 株式会社ブリヂストン tire
WO2010137089A1 (en) * 2009-05-29 2010-12-02 株式会社ブリヂストン Tire
JP2010274860A (en) * 2009-05-29 2010-12-09 Bridgestone Corp Tire
KR101152099B1 (en) 2009-05-29 2012-06-08 가부시키가이샤 브리지스톤 Tire
US8397773B2 (en) 2009-05-29 2013-03-19 Bridgestone Corporation Tire with tread having circumferential grooves, first resonators and second resonators
US20130263984A1 (en) * 2010-10-14 2013-10-10 Michelin Recherche Et Technique S.A. Noise attenuator devices for tires
CN112606629A (en) * 2020-12-28 2021-04-06 合肥工业大学 Wide band low noise pneumatic tire tread pattern
CN112606629B (en) * 2020-12-28 2022-06-07 合肥工业大学 Wide band low noise pneumatic tire tread pattern

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