JP3357458B2 - Pneumatic radial tire - Google Patents
Pneumatic radial tireInfo
- Publication number
- JP3357458B2 JP3357458B2 JP12275694A JP12275694A JP3357458B2 JP 3357458 B2 JP3357458 B2 JP 3357458B2 JP 12275694 A JP12275694 A JP 12275694A JP 12275694 A JP12275694 A JP 12275694A JP 3357458 B2 JP3357458 B2 JP 3357458B2
- Authority
- JP
- Japan
- Prior art keywords
- tire
- groove
- reinforcing element
- lateral groove
- tread
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Fee Related
Links
Landscapes
- Tires In General (AREA)
- Soundproofing, Sound Blocking, And Sound Damping (AREA)
Description
【0001】[0001]
【産業上の利用分野】この発明は、空気入りラジアルタ
イヤにおいて、特にパターンノイズの改善と湿潤路走行
性の改良に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pneumatic radial tire, and more particularly to an improvement in pattern noise and an improvement in wet road running performance.
【0002】[0002]
【従来の技術】一般に、パターンノイズは、トレッド表
面に刻まれた周方向の繰返し模様、いわゆる“パター
ン”の繰り返しに発生原因があり、“パターン”の繰り
返し、即ちピッチが、タイヤの転動時に順次路面を衝撃
的に打つことで生じる。従ってパターンノイズは、この
ピッチ数とタイヤの回転数とで決まる周波数の振動がタ
イヤを振動せしめるため、この振動音が主体をなしてい
る。2. Description of the Related Art Generally, pattern noise is caused by repetition of a so-called "pattern", which is a circumferential repetitive pattern engraved on a tread surface. It is caused by striking the road surface sequentially. Therefore, the pattern noise is mainly composed of the vibration noise because the vibration of the frequency determined by the pitch number and the rotation speed of the tire causes the tire to vibrate.
【0003】従って、従来の騒音低減方策は、リブパタ
ーンでは、一般的に多く用いられている手段として、図
7に示す様に、縦溝1のジグザグを小さく或いは除去し
てストレート基調とし、振動発生の原因であるタイヤ回
転方向に直角な溝成分を小さくしたタイヤが提供されて
いる。図7中、3は縦溝1によって区分されたリブ状の
陸部である。Therefore, in the conventional noise reduction method, as a generally used means in a rib pattern, as shown in FIG. There is provided a tire in which a groove component perpendicular to the tire rotation direction, which is a cause of the occurrence, is reduced. In FIG. 7, reference numeral 3 denotes a rib-shaped land portion divided by the vertical groove 1.
【0004】またブロックを有するパターンでは、図8
に示す様に、横溝2の幅を狭く深さを小さくし、横溝2
を周方向に沿う方向に角度をかえて接地に要する時間を
長くして衝撃力を小さくし、又はトレッド部のゴムをや
わらかくして衝撃エネルギーを小さくする方法がとられ
てきた。In a pattern having blocks, FIG.
As shown in the figure, the width of the lateral groove 2 is reduced and the depth thereof is reduced.
In order to reduce the impact force by increasing the time required for ground contact by changing the angle in the direction along the circumferential direction, or to reduce the impact energy by softening the rubber of the tread portion.
【0005】このほかにも、例えば特開平2−4190
9号に開示されているように、横溝の方向(角度)を特
定して一方向性を持たせることにより低減させたタイヤ
がある。またパターンのピッチ長をランダム化したタイ
ヤも提供されている。In addition, for example, Japanese Patent Application Laid-Open No.
As disclosed in Japanese Patent No. 9, there is a tire in which the direction (angle) of the lateral groove is specified to have a unidirectional property to reduce the tire. Tires with randomized pattern pitch lengths are also provided.
【0006】[0006]
【発明が解決しようとする課題】しかし、縦溝を小さく
ストレート基調としたリブタイプのタイヤの場合、パタ
ーンノイズの低減、偏摩耗性の改良には有効なるも、湿
潤路での制動性が劣り、安全性に欠ける難点がある。ま
た横溝の幅を狭く深さを小さくしたブロックタイプのタ
イヤの場合は、排水性を不良にするためタイヤ〜路面間
に水膜を形成し易く、路面との摩擦係数を下げるため、
湿潤路での制動性能が低下する。またブロックタイプの
横溝をタイヤ周方向に沿う方向に角度をかえて配列する
と、横溝と縦溝との交差部に形成されるブロックの一部
が鋭角状となり、この部分で剛性が極端に変化して偏摩
耗が生じやすくなる。However, in the case of a rib type tire having a small longitudinal groove and a straight tone, it is effective for reducing pattern noise and improving uneven wear, but has poor braking performance on wet roads, There are disadvantages that lack security. In addition, in the case of a block type tire having a narrow width and a small width of the lateral groove, a water film is easily formed between the tire and the road surface to make the drainage performance inferior, and a coefficient of friction with the road surface is reduced,
The braking performance on wet roads decreases. Also, when the block type lateral grooves are arranged at different angles in the direction along the tire circumferential direction, part of the block formed at the intersection of the lateral groove and the vertical groove becomes an acute angle, and the rigidity changes extremely at this part. This tends to cause uneven wear.
【0007】ゴムを柔らかくして接地時の衝撃力を小さ
くしたタイヤでは、撓みに伴うトレッド表面の変形、ひ
いてはすべりを大きくするため偏摩耗の発生が助長され
る。またパターンが一方向性の形状を有するブロックパ
ターンについては、パターンも偏摩耗性も回転方向によ
って大幅に変化し、良好な結果を維持し続けるために
は、タイヤの回転方向を常に一定とする必要があり、こ
のことは車両管理者にとってはメンテナンス上極めて煩
雑となる。[0007] In a tire in which the rubber is softened to reduce the impact force at the time of contact with the ground, deformation of the tread surface due to bending and, consequently, slippage are increased, so that uneven wear is promoted. In the case of a block pattern having a unidirectional shape, both the pattern and the uneven wear vary greatly depending on the rotation direction, and in order to maintain good results, the rotation direction of the tire must be always constant. This is extremely complicated for the vehicle manager in terms of maintenance.
【0008】パターンのピッチ長をランダム化する方法
は、長さの比がノイズ低減に有効とするためには少なく
とも1:1.5以上が必要であり、この場合、ピッチの
大きさの差、即ち剛性差が直ちにトレッド表面のすべり
の差となるため、偏摩耗として出現する問題がある。The method of randomizing the pitch length of the pattern requires at least 1: 1.5 or more in order for the length ratio to be effective for noise reduction. In this case, the difference in pitch size, That is, since the difference in rigidity immediately becomes the difference in slip on the tread surface, there is a problem that it appears as uneven wear.
【0009】本発明の目的は、湿潤路でのトラクション
性、制動性を損なうことなく、パターンノイズの低減化
を図ることができる空気入りラジアルタイヤを提供する
点にある。An object of the present invention is to provide a pneumatic radial tire capable of reducing pattern noise without impairing traction and braking on wet roads.
【0010】[0010]
【課題を解決するための手段】パターンノイズの主要因
は、既述した様に、トレッド表面に形成されたパターン
の特に横溝或いは縦溝のトレッド幅方向成分(横溝成
分)によってタイヤ周方向に不連続となった陸部が路面
に対し不連続に接触して発生する衝撃力がタイヤを加振
する事による振動音にある。これは特に横溝の幅が広く
なるほど、また深く長くなるほど強くあらわれる。As described above, the main factor of the pattern noise is that the pattern formed on the surface of the tread has a problem in the circumferential direction of the tire due to the component in the tread width direction (horizontal groove component) particularly of the horizontal groove or the vertical groove. The impact force generated when the continuous land portion comes into discontinuous contact with the road surface is the vibration sound caused by exciting the tire. This is particularly apparent as the width of the lateral groove becomes wider and deeper and longer.
【0011】振動音の発生は、平歯車を硬い平面で転が
す事にたとえることが出来る。つまり、タイヤの外周を
形成する円が横溝で分断され、分断部分のタイヤ回転中
心軸〜路面間の距離が分断部以外より小さく、一ピッチ
毎の接地時にタイヤの回転中心が変わり、タイヤを上下
させることで生じる。従って溝幅は広いほどその影響が
強くなる。さらにこの溝幅の効果のほかに、図9に示す
如く、陸部3のトレッド部Tにおける溝開口端5は、陸
部3の内側よりもタイヤ補強層であるベルト層Bからの
拘束が横溝2で分断されるため弱くなり、タイヤ製造の
最終段階である加硫工程で、金型内で高温、高圧で成形
加硫した後、高温から室温に冷却するときに収縮がおこ
り、陸部の溝開口端5に形状的なはね上がりが生じ、こ
れによりタイヤ円周の不連続性が強くなるから、加振力
が増加するものである。なお、図中、鎖線はタイヤ成型
用金型Mの位置形状を示している。The generation of vibration noise can be compared to rolling a spur gear on a hard plane. In other words, the circle forming the outer circumference of the tire is divided by the lateral groove, the distance between the tire rotation center axis and the road surface of the divided part is smaller than that of the part other than the divided part, the rotation center of the tire changes at the time of ground contact at every pitch, and the tire This is caused by Therefore, the effect is stronger as the groove width is wider. Further, in addition to the effect of the groove width, as shown in FIG. 9, the groove opening end 5 in the tread portion T of the land portion 3 is more restrained by the belt layer B which is the tire reinforcing layer than the inner side of the land portion 3. In the vulcanization process, which is the final stage of tire production, after vulcanization at high temperature and high pressure in the mold, shrinkage occurs when cooling from high temperature to room temperature. The shape opening of the groove opening end 5 causes a discontinuity of the circumference of the tire, thereby increasing the excitation force. In addition, in the figure, the chain line shows the position shape of the tire molding die M.
【0012】そこで本発明は、この横溝の幅効果と溝開
口端のはね上がり効果を小さくし、振動音を抑制しよう
とするものであり、タイヤ周方向に延在する複数の縦溝
と該縦溝に開口する横溝とによってブロック状の陸部を
トレッド部に多数形成した空気入りタイヤにおいて、上
記陸部と横溝との境界部をなす陸部側壁面には、互いに
対向する陸部側壁面との間で、横溝の踏面部開口端から
溝底側に向かって漸次断面積が増大する複数個の補強要
素が、互いにいわばフォーク状にジグザグ状態において
入り込む状態、すなわち交互に入り込んで断面形状にお
いて互いに重なり合う状態で突出形成されている構成を
採用した。Accordingly, the present invention is intended to reduce the width effect of the lateral groove and the effect of the bounce of the groove opening end to suppress vibration noise, and to provide a plurality of longitudinal grooves extending in the tire circumferential direction and the longitudinal grooves. In a pneumatic tire in which a large number of block-shaped land portions are formed in a tread portion by a lateral groove that opens to a land portion side wall surface that defines a boundary between the land portion and the lateral groove, a land portion side wall surface facing each other is formed. In the meantime, a plurality of reinforcing elements whose cross-sectional area gradually increases from the tread portion opening end of the lateral groove toward the groove bottom side are in a zigzag state, that is, in a so-called fork-like state, that is, they alternately enter and overlap each other in a cross-sectional shape. A configuration in which the projection is formed in a state is adopted.
【0013】すなわち、前記補強要素で開口端と横溝底
とを連結して陸部に拘束性を与え、これにより横溝の踏
面部開口端の陸部の形状的なはね上がりを防止する構成
である。[0013] That is, the opening end and the bottom of the lateral groove are connected by the reinforcing element to give the land part a restraining property, thereby preventing the land part at the tread surface opening end of the lateral groove from bouncing up.
【0014】これは補強要素の溝底にむけての長さの拡
大が大きいほど、つまり補強要素の横溝の踏面部開口端
から溝底側に向かっての断面積の増大の程度が大きい程
いわゆるリブとしての補強効果が大きく、振動騒音の低
減につながる。振動騒音の低減に所望の効果を得るため
には、補強要素の断面形状において、踏面部開口端から
タイヤ中心方向に垂直に下ろした横溝底の地点aから補
強要素の最端地点bまでの補強要素の長さLが、少なく
とも横溝深さHの30%必要である。横溝深さHの30
%未満の場合、陸部の拘束性の点で必ずしも充分とはい
えず、陸部の形状的なはね上がりを防止する上で、振動
騒音の低減化につながりにくいためである。補強要素の
長さLの上限は、タイヤの生産工程上の問題とモールド
加工上の問題のほか、陸部の剛性低下にともなう偏摩耗
の増加から自ずと制限される。This is because the larger the length of the reinforcing element toward the groove bottom, that is, the larger the degree of increase in the cross-sectional area from the tread opening end of the lateral groove of the reinforcing element toward the groove bottom, the so-called. The reinforcing effect as a rib is large, leading to a reduction in vibration noise. In order to obtain the desired effect on the reduction of vibration noise, in the cross-sectional shape of the reinforcing element, the reinforcement from the point a at the bottom of the lateral groove lowered vertically from the tread opening end to the center of the tire to the end point b of the reinforcing element The element length L must be at least 30% of the lateral groove depth H. 30 of horizontal groove depth H
If it is less than%, it is not necessarily sufficient in terms of the restraint of the land portion, and it is difficult to reduce vibration noise in preventing the land portion from rising. The upper limit of the length L of the reinforcing element is naturally limited due to a problem in a tire production process and a problem in molding, and also an increase in uneven wear due to a decrease in rigidity of a land portion.
【0015】また振動騒音の低減を図るためには、横溝
の幅効果を小さくすることもまた重要であるが、補強要
素の溝底に向かっての拡大は、タイヤの摩耗に従って補
強要素の長さが大きく表れ、陸部端からフォーク状に突
出し、かつ対向陸部からの補強要素と重なるから、補強
要素で負荷を受け、横溝の幅効果に結びつくタイヤの回
転中心からの距離の変化を小さくし、加振力低減により
振動音を小さくする。In order to reduce the vibration noise, it is also important to reduce the width effect of the lateral groove. However, the expansion of the reinforcing element toward the groove bottom depends on the length of the reinforcing element according to the wear of the tire. Appears large and protrudes in a fork form from the end of the land, and overlaps with the reinforcing element from the opposite land, so that the load on the reinforcing element reduces the change in distance from the center of rotation of the tire, which leads to the width effect of the lateral groove. The vibration noise is reduced by reducing the excitation force.
【0016】この点で、横溝の幅効果を一層小さくする
ためには、横溝の幅が踏面部開口端から溝底側に向かっ
て漸次拡がる方向に、互いに対向する陸部側壁面を傾斜
して構成し、補強要素を、横溝の踏面部開口端から、対
向する当該陸部側壁面の溝底側端部にまで延びるように
することが適切である。In this respect, in order to further reduce the width effect of the lateral groove, the width of the lateral groove is increased from the tread opening end to the groove bottom side.
Progressively expanding direction Te, and configure inclined obliquely the land portion side wall facing each other, the reinforcing elements, so as to extend from the tread opening ends of the lateral grooves, to the groove bottom side end portion of the land portion side opposing wall surfaces Is appropriate.
【0017】なお、補強要素の形状は特に限定されず、
例えば3角形状、短形の補強要素が例示できる。また、
本発明の陸部は「ブロック状」の陸部であればよく、い
わゆるブロックパターンのみならず、リブパターンであ
っても差支えない。ブロックパターン、リブパターンの
区別は横溝の深さに応じておよそ定められる種別にすぎ
ないからである。The shape of the reinforcing element is not particularly limited.
For example, a triangular or short reinforcing element can be exemplified. Also,
The land portion of the present invention may be a “block-shaped” land portion, and may be not only a so-called block pattern but also a rib pattern. This is because the distinction between the block pattern and the rib pattern is only a type roughly determined according to the depth of the lateral groove.
【0018】横溝の幅はタイヤ接地時に容易に塞がるこ
とのない幅を有していることが好ましい。具体的には横
溝の踏面部開口端間の寸法で少なくとも2mm以上である
ことが望ましい。It is preferable that the width of the lateral groove has a width that does not easily block when the tire is in contact with the ground. Specifically, it is desirable that the dimension between the open ends of the treads of the lateral grooves is at least 2 mm or more.
【0019】[0019]
【作用】この発明は、タイヤ周方向に延在する複数の縦
溝と該縦溝に開口する横溝とによってブロック状の陸部
をトレッド部に多数形成した空気入りタイヤにおいて、
上記横溝はタイヤ接地時に塞がることのない幅を有して
おり、上記陸部と横溝との境界部をなす陸部側壁面に
は、対向する陸部側壁面との相互間で、横溝の踏面部開
口端から溝底側に向かって漸次断面積が増大する複数個
の補強要素が、互いにジグザグ状に入り込む状態で突出
形成されている空気入りラジアルタイヤであるので、補
強要素で陸部の開口端と横溝底とを連結して当該陸部に
拘束性を与えてタイヤ成形加硫後の高温からの冷却の際
に、横溝の踏面部開口端の陸部の形状的なはね上がりを
防止し、タイヤ円周の連続性を高めることができる。ま
た、補強要素の溝底に向かっての拡大は、タイヤの摩耗
に従って補強要素の長さが大きく表れ、陸部端からフォ
ーク状に突出し、かつ対向陸部からの補強要素と重なる
から、補強要素で負荷を受け、横溝の幅効果に結びつく
路面とタイヤの回転中心軸からの距離の変化を小さく
し、加振力低減により振動音を小さくする。According to the present invention, there is provided a pneumatic tire in which a large number of block-shaped land portions are formed in a tread portion by a plurality of vertical grooves extending in a tire circumferential direction and a horizontal groove opening in the vertical grooves.
The lateral groove has a width that does not block when the tire is in contact with the ground, and the lateral side wall surface defining the boundary between the land portion and the lateral groove has a step between the opposing land side wall surfaces. A plurality of reinforcing elements whose cross-sectional areas gradually increase from the surface opening end toward the groove bottom are pneumatic radial tires that are formed so as to protrude in a zigzag shape with respect to each other. At the time of cooling from a high temperature after vulcanization of the tire by connecting the end and the bottom of the lateral groove to provide a restraining property to the land, the shape of the land at the opening end of the tread opening of the lateral groove is prevented from rising, The continuity of the tire circumference can be improved. In addition, the expansion of the reinforcing element toward the groove bottom increases the length of the reinforcing element according to the wear of the tire, protrudes in a fork shape from the end of the land portion, and overlaps with the reinforcing element from the opposite land portion. And reduces the change in the distance from the center of rotation of the tire to the road surface, which is linked to the width effect of the lateral groove, and reduces vibration noise by reducing the excitation force.
【0020】また、従来の様に縦溝を小さくストレート
基調とするものではなく、横溝の幅を狭く深さを小さく
しない一方で、補強要素の存在は周方向のブロック剛性
を増すから、負荷がかかっても横溝が塞がることなく排
水性を確保出来るので、湿潤路でのトラクション性、制
動性を損なうことなく、パターンノイズの低減化を図る
ことができる。Further, the vertical grooves are not made smaller and straighter as in the prior art, and the width of the horizontal grooves is made smaller and the depth is not made smaller. On the other hand, the presence of the reinforcing element increases the block rigidity in the circumferential direction. Even if it is applied, the drainage can be ensured without blocking the lateral groove, so that the pattern noise can be reduced without impairing the traction and braking on wet roads.
【0021】[0021]
【実施例】図1は本発明に係る空気入りタイヤの一実施
例を示すトレッドパターンの概略図、2は同A−A線断
面図、図3は要部拡大概略斜視図である。FIG. 1 is a schematic view of a tread pattern showing an embodiment of a pneumatic tire according to the present invention, 2 is a sectional view taken along the line AA, and FIG. 3 is an enlarged schematic perspective view of a main part.
【0022】図において、1はタイヤトレッド部Tにお
いてタイヤ周方向に延在する複数の縦溝、2は該縦溝1
に開口する横溝、3は縦溝1と横溝2で区分されたブロ
ック状の陸部、Sはショルダー側の陸部、SEはショル
ダー端である。4は陸部3と横溝2との境界部をなす陸
部側壁面である。In the figure, reference numeral 1 denotes a plurality of longitudinal grooves extending in the tire circumferential direction in a tire tread portion T;
3 is a block-shaped land portion divided by the vertical groove 1 and the horizontal groove 2, S is a land portion on the shoulder side, and SE is a shoulder end. Reference numeral 4 denotes a land portion side wall surface which forms a boundary between the land portion 3 and the lateral groove 2.
【0023】横溝2はタイヤ接地時に容易に塞がること
のない幅Wを有しており、陸部側壁面4には、対向する
陸部側壁面4との相互間で、横溝2の踏面部開口端5か
ら溝底6側に向かって漸次断面積が増大する複数個の補
強要素7が、交互に入り込んで断面形状において重なり
合う状態で突出形成されている。The lateral groove 2 has a width W that does not easily close when the tire is in contact with the ground, and the land side wall surface 4 has a tread surface opening of the lateral groove 2 between the opposing land side wall surfaces 4. A plurality of reinforcing elements 7 having a gradually increasing cross-sectional area from the end 5 toward the groove bottom 6 are formed so as to alternately enter and overlap in cross-sectional shape.
【0024】特に本実施例では、互いに対向する陸部側
壁面4、4は、横溝2の幅1Wが横溝2の踏面部開口端
5から溝底6側に向かって漸次拡がる方向に傾斜してお
り、補強要素7は、横溝2の踏面部開口端5から、対向
する当該陸部側壁面4の溝底側端部8にまで三角状をし
て延びており、補強要素の断面形状において、踏面部開
口端5よりタイヤ中心方向に垂直に下ろした横溝底の地
点aから補強要素7の最端地点bまでの補強要素の長さ
Lが横溝深さHの35%となっている。In particular, in this embodiment, the land side wall surfaces 4, 4 facing each other are inclined in a direction in which the width 1W of the lateral groove 2 gradually expands from the tread opening end 5 of the lateral groove 2 toward the groove bottom 6. The reinforcing element 7 extends in a triangular shape from the tread opening end 5 of the lateral groove 2 to the groove bottom side end 8 of the land side wall surface 4 facing the same, and in the cross-sectional shape of the reinforcing element, The length L of the reinforcing element from the point a at the bottom of the lateral groove, which is vertically lowered from the tread surface opening end 5 in the tire center direction, to the end point b of the reinforcing element 7 is 35% of the lateral groove depth H.
【0025】従って、補強要素7で陸部3における横溝
2の踏面部開口端5と溝底6とを連結して当該陸部3に
拘束性を与えることができるので、タイヤ成型の際、高
温から室温に冷却するときに生じる熱収縮に起因して、
陸部端に形状的なはね上がりが生じることもなく、タイ
ヤ円周の連続性を高めることができる。また、補強要素
の溝底6に向かっての増加は、タイヤの摩耗に従って補
強要素の長さが大きく表れ、陸部3端からフォーク状に
突出し、かつ対向陸部3からの補強要素7と重なるか
ら、補強要素7で負荷を受け、横溝2の幅効果に結びつ
くタイヤの回転中心軸から路面までの距離の変化を小さ
くし、加振力の低減によって振動音を小さくする。Accordingly, the tread surface opening end 5 of the lateral groove 2 in the land portion 3 and the groove bottom 6 can be connected by the reinforcing element 7 so that the land portion 3 can be restrained. Due to the heat shrinkage that occurs when cooling from
The continuity of the circumference of the tire can be improved without the occurrence of a shape jump at the land portion end. In addition, the increase of the reinforcing element toward the groove bottom 6 indicates that the length of the reinforcing element increases as the tire wears, protrudes like a fork from the end of the land portion 3, and overlaps with the reinforcing element 7 from the opposite land portion 3. Therefore, a change in the distance from the center axis of rotation of the tire to the road surface, which is loaded with the reinforcing element 7 and leads to the width effect of the lateral groove 2, is reduced, and the vibration force is reduced by reducing the exciting force.
【0026】従ってこの補強要素7の存在は周方向のブ
ロック剛性を増すから、負荷がかかっても横溝2は塞が
ることなく排水性を確保出来るので、湿潤路でのトラク
ション性、制動性を損なうことなく、パターンノイズの
低減化を図ることができる。ところでこの発明は上記実
施例に限定されない。例えば、互いに対向する陸部側壁
面4、4は、横溝2の幅Wが横溝2の踏面部開口端5か
ら溝底6側に向かって漸次拡がる方向に傾斜することな
く、図4および図5に示す様に、陸部側壁面4、4と溝
底6とで形成する形状がU型又はV型をなし、これに応
じて、補強要素7を、横溝2の踏面部開口端5から、対
向する当該陸部側壁面4の溝底側端部8にまで延びるよ
うにしても差支えない。Therefore, the presence of the reinforcing element 7 increases the rigidity of the block in the circumferential direction, so that even when a load is applied, the lateral groove 2 can be secured without drainage, so that traction and braking on wet roads are impaired. In addition, pattern noise can be reduced. The present invention is not limited to the above embodiment. For example, the land side wall surfaces 4 and 4 facing each other are not inclined in a direction in which the width W of the lateral groove 2 gradually expands from the tread surface opening end 5 of the lateral groove 2 toward the groove bottom 6, and FIGS. As shown in the figure, the shape formed by the land side wall surfaces 4 and 4 and the groove bottom 6 is U-shaped or V-shaped, and accordingly, the reinforcing element 7 is moved from the tread surface opening end 5 of the lateral groove 2 to It can be extended to the groove bottom side end 8 of the land side wall surface 4 that faces the same.
【0027】また補強要素の形状も、横溝2の踏面部開
口端5から、対向する当該陸部側壁面4の溝底側端部8
にまで三角状をして延びる構成ではなく、図6に示す様
に、矩形状にして延びる構成でも差支えない。The shape of the reinforcing element is also changed from the tread surface opening end 5 of the lateral groove 2 to the groove bottom side end 8 of the land side wall surface 4 facing the same.
Instead of the configuration extending in a triangular shape, a configuration extending in a rectangular shape as shown in FIG.
【0028】次に、タイヤサイズ10,00R20 1
4PRである図1及び図4にそれぞれ相当するAパター
ン及びBパターンのタイヤを試作して、タイヤノイズ及
び制動性について評価した。比較のため、図1及び図4
においてそれぞれ補強要素を有しない図7及び図8に相
当するAパターン及びBパターン各々のタイヤについて
も評価した。Next, a tire size of 10,000 R20 1
A tire having an A pattern and a B pattern corresponding to 4PR in FIGS. 1 and 4, respectively, was prototyped and evaluated for tire noise and braking performance. For comparison, FIGS. 1 and 4
The tires of each of the A pattern and the B pattern corresponding to FIGS. 7 and 8 having no reinforcing element were also evaluated.
【0029】タイヤノイズは、JASO C606 タ
イヤ台上車体試験法によって騒音試験をした。なおノイ
ズレベルは、速度が20〜120km/h でのレベルの平
均値をとった。湿潤路制動性は、2−D車の6輪ともに
テストタイヤを装着し、定積等価負荷の条件下、湿潤テ
ストコースで実走テストした。For tire noise, a noise test was carried out by a JASO C606 tire base on-body test method. The noise level was an average of the levels at speeds of 20 to 120 km / h. For the wet road braking performance, a test tire was mounted on each of the six wheels of the 2-D vehicle, and an actual running test was performed on a wet test course under the condition of constant load equivalent load.
【0030】いずれの試験も、AパターンおよびBパタ
ーンの実施例タイヤそれぞれについて、補強要素を有し
ない図7及び図8に相当するAパターン及びBパターン
を各々100としての指数表示した。いずれも数字の小
さい方が良好であることを示している。なおいずれのタ
イヤも材質は同一である。In each of the tests, the A pattern and the B pattern corresponding to FIGS. 7 and 8 having no reinforcing element were indicated by an index of 100 for each of the example tires having the A pattern and the B pattern. In each case, the smaller the number, the better. The materials of all tires are the same.
【0031】図10はノイズレベル及び湿潤路制動性の
テスト結果を示している。FIG. 10 shows the test results of the noise level and wet road braking performance.
【0032】図10中、L/H=0が補強要素を有しな
い図7及び図8に相当するAパターン及びBパターン各
々の比較例タイヤであり、L/H≠0のプロットは補強
要素を有する実施例タイヤである。In FIG. 10, L / H = 0 is a comparative example tire of each of the A pattern and the B pattern corresponding to FIGS. 7 and 8 having no reinforcing element, and the plot of L / H ≠ 0 indicates the reinforcing element. It is an example tire having.
【0033】図10より、L/Hが大きくなればなるほ
ど、本発明のタイヤは比較例タイヤと比較していずれも
パターンノイズが良好であることが理解できる。特にパ
ターンノイズは、L/Hが20%を越えると急激にノイ
ズレベル指数がダウンし、L/Hが30%以上の場合
は、パターンノイズ及び湿潤路での走行性が顕著に良好
であることが認められる。From FIG. 10, it can be understood that the larger the L / H, the better the pattern noise of the tire according to the present invention as compared with the comparative tire. In particular, when the L / H exceeds 20%, the noise level index sharply decreases, and when the L / H is 30% or more, the pattern noise and running performance on wet roads are remarkably good. Is recognized.
【0034】一方、湿潤路での制動性能は、補強要素の
有無にかかわらず、ほとんど変化がなく、悪化すること
がない。On the other hand, the braking performance on a wet road hardly changes and does not deteriorate regardless of the presence or absence of the reinforcing element.
【0035】[0035]
【発明の効果】この発明は、上記横溝はタイヤ接地時に
塞がることのない幅を有しており、上記陸部と横溝との
境界部をなす陸部側壁面には、対向する陸部側壁面との
相互間で、横溝の踏面部開口端から溝底側に向かって漸
次断面積が増大する複数個の補強要素が、互いにジグザ
グ状に入り込む状態で突出形成されている空気入りタイ
ヤであるので、補強要素で陸部の開口端と横溝底とを連
結して当該陸部に拘束性が付与される結果、タイヤ成型
時の熱収縮の際に横溝の踏面部開口端に生じる陸部の形
状的なはね上がりを防止し、タイヤ円周の連続性を高め
てパターンノイズの低減化を図ることができる。According to the present invention, the lateral groove has a width which does not close when the tire is in contact with the ground, and the land side wall surface which forms the boundary between the land portion and the lateral groove has a land side wall surface facing the land portion. A plurality of reinforcing elements whose cross-sectional area gradually increases from the tread opening opening end of the lateral groove toward the groove bottom are pneumatic tires formed so as to protrude in a zigzag shape with each other. As a result, the reinforcing element connects the open end of the land portion and the bottom of the lateral groove to provide the land portion with the restraining property, and as a result, the shape of the land portion generated at the open end of the tread portion of the lateral groove during thermal contraction during tire molding. It is possible to prevent the target bounce and enhance the continuity of the tire circumference to reduce the pattern noise.
【0036】また、補強要素の溝底に向かっての拡大
は、タイヤの摩耗に従って補強要素の長さが大きく表
れ、陸部端からフォーク状に突出し、かつ対向陸部から
の補強要素と重なるから、補強要素で負荷を受け、横溝
の幅効果に結びつくタイヤの回転中心軸からの距離の変
化を小さくし、加振力低減により摩耗が進行していく過
程においても振動音を小さくする。Further, the expansion of the reinforcing element toward the groove bottom causes the length of the reinforcing element to be large as the tire wears, protruding in a fork shape from the land portion end, and overlapping with the reinforcing element from the opposite land portion. In addition, a change in the distance from the rotation center axis of the tire, which is loaded by the reinforcing element and leads to the width effect of the lateral groove, is reduced, and the vibration noise is reduced even in a process in which the wear progresses due to the reduction in the excitation force.
【0037】また、補強要素の存在は周方向のブロック
剛性を増すから、負荷がかかっても横溝は塞がることな
く排水性を確保出来るので、湿潤路でのトラクション
性、制動性を損なうことなく、パターンノイズの低減を
図ることができる。Further, since the presence of the reinforcing element increases the block rigidity in the circumferential direction, even if a load is applied, the drainage can be secured without closing the lateral groove, so that the traction and braking performance on wet roads are not impaired. Pattern noise can be reduced.
【0038】特に、補強要素の断面形状において、踏面
部開口端よりタイヤ中心方向に垂直に下ろした横溝底の
地点aから補強要素の最端地点bまでの補強要素の長さ
Lが横溝深さHとの関係で、L/Hが30%以上の場合
は、パターンノイズ及び湿潤路での走行性が顕著に良好
である。In particular, in the cross-sectional shape of the reinforcing element, the length L of the reinforcing element from the point a of the bottom of the lateral groove, which is lowered vertically from the opening end of the tread portion to the center of the tire, to the extreme point b of the reinforcing element is the lateral groove depth. When L / H is 30% or more in relation to H, pattern noise and running on wet roads are remarkably good.
【図1】本発明に係る空気入りタイヤの一実施例を示す
トレッドパターンの概略図である。FIG. 1 is a schematic view of a tread pattern showing one embodiment of a pneumatic tire according to the present invention.
【図2】同A−A線断面図である。FIG. 2 is a sectional view taken along line AA of FIG.
【図3】要部拡大概略斜視図である。FIG. 3 is an enlarged schematic perspective view of a main part.
【図4】本発明に係る空気入りタイヤの他実施例を示す
トレッドパターンの概略図である。FIG. 4 is a schematic view of a tread pattern showing another embodiment of the pneumatic tire according to the present invention.
【図5】同B−B線断面図である。FIG. 5 is a sectional view taken along line BB in FIG.
【図6】矩形状の補強要素を示す要部拡大概略斜視図で
ある。FIG. 6 is an enlarged schematic perspective view of a main part showing a rectangular reinforcing element.
【図7】従来タイヤのパターンを示す概略図である。FIG. 7 is a schematic view showing a pattern of a conventional tire.
【図8】ブロックパターンの従来タイヤを示す概略図で
ある。FIG. 8 is a schematic view showing a conventional tire having a block pattern.
【図9】タイヤ成型時の陸部の溝開口端のはね上がり状
態を示す要部拡大断面図である。FIG. 9 is an enlarged cross-sectional view of a main part showing a state in which a groove opening end of a land portion is raised when a tire is molded.
【図10】ノイズレベル指数及び制動性指数と、L/H
との関係を示すグラフである。FIG. 10 shows a noise level index and a damping index, and L / H.
6 is a graph showing a relationship with the graph.
1 縦溝 2 横溝 3 陸部 4 陸部側壁面 5 踏面部開口端 6 溝底 7 補強要素 8 溝底側端部 T トレッド部 L 補強要素の長さ H 横溝深さ W 横溝の幅 Reference Signs List 1 vertical groove 2 horizontal groove 3 land portion 4 land portion side wall surface 5 tread opening end 6 groove bottom 7 reinforcing element 8 groove bottom side end T tread part L reinforcing element length H horizontal groove depth W horizontal groove width
Claims (3)
溝に開口する横溝とによってブロック状の陸部をトレッ
ド部に多数形成した空気入りタイヤにおいて、上記陸部
と横溝との境界部をなす陸部側壁面には、互いに対向す
る陸部側壁面との間で、横溝の踏面部開口端から溝底側
に向かって漸次断面積が増大する複数個の補強要素が、
交互に入り込んで重なり合う状態で突出形成されている
ことを特徴とする空気入りラジアルタイヤ。1. A pneumatic tire in which a plurality of block-shaped land portions are formed in a tread portion by a plurality of vertical grooves extending in a tire circumferential direction and a horizontal groove opening in the vertical grooves. On the land side wall surface forming the boundary, between the land side wall surfaces facing each other, a plurality of reinforcing elements whose cross-sectional area gradually increases from the tread surface opening end of the lateral groove toward the groove bottom side,
A pneumatic radial tire characterized by being formed so as to alternately enter and overlap one another.
って漸次拡がる方向に、互いに対向する陸部側壁面は傾
斜しており、補強要素は、横溝の踏面部開口端から、対
向する当該陸部側壁面の溝底側端部にまで延びている請
求項1記載の空気入りラジアルタイヤ。2. The width of the lateral groove is from the tread opening end to the groove bottom side.
The land side walls opposing each other are inclined in the direction in which the side walls gradually incline, and the reinforcing element is provided at the groove bottom side end of the land side wall opposite to the tread surface opening end of the lateral groove. The pneumatic radial tire according to claim 1, which extends to:
端よりタイヤ中心方向に垂直に下ろした横溝底の地点a
から補強要素の最端地点bまでの補強要素の長さLが、
少なくとも横溝深さHの30%である請求項1又は2記
載の空気入りラジアルタイヤ。3. The cross-sectional shape of the reinforcing element, a point a at the bottom of the lateral groove which is lowered vertically from the tread opening end to the center of the tire.
The length L of the reinforcing element from the end point b of the reinforcing element to
The pneumatic radial tire according to claim 1 or 2, wherein the depth is at least 30% of the transverse groove depth H.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP12275694A JP3357458B2 (en) | 1994-06-03 | 1994-06-03 | Pneumatic radial tire |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP12275694A JP3357458B2 (en) | 1994-06-03 | 1994-06-03 | Pneumatic radial tire |
Publications (2)
Publication Number | Publication Date |
---|---|
JPH07329511A JPH07329511A (en) | 1995-12-19 |
JP3357458B2 true JP3357458B2 (en) | 2002-12-16 |
Family
ID=14843839
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
JP12275694A Expired - Fee Related JP3357458B2 (en) | 1994-06-03 | 1994-06-03 | Pneumatic radial tire |
Country Status (1)
Country | Link |
---|---|
JP (1) | JP3357458B2 (en) |
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP2010058568A (en) * | 2008-09-02 | 2010-03-18 | Yokohama Rubber Co Ltd:The | Pneumatic tire |
Families Citing this family (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US6412531B1 (en) * | 1999-07-15 | 2002-07-02 | Michelin Recherche Et Technique S.A. | Tire tread having groove walls with compound contours |
DE60218286T2 (en) * | 2001-01-29 | 2007-11-08 | Société de Technologie Michelin | ROLLER NOISE REDUCING RUNNING ROOF |
JP5455778B2 (en) * | 2010-05-13 | 2014-03-26 | 東洋ゴム工業株式会社 | Pneumatic tire |
EP3313672B1 (en) | 2015-06-29 | 2020-11-18 | Compagnie Générale des Etablissements Michelin | Tire tread for reducing noise |
-
1994
- 1994-06-03 JP JP12275694A patent/JP3357458B2/en not_active Expired - Fee Related
Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP2010058568A (en) * | 2008-09-02 | 2010-03-18 | Yokohama Rubber Co Ltd:The | Pneumatic tire |
JP4650540B2 (en) * | 2008-09-02 | 2011-03-16 | 横浜ゴム株式会社 | Pneumatic tire |
Also Published As
Publication number | Publication date |
---|---|
JPH07329511A (en) | 1995-12-19 |
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