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JP3606459B2 - Pneumatic tire - Google Patents

Pneumatic tire Download PDF

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Publication number
JP3606459B2
JP3606459B2 JP2001271329A JP2001271329A JP3606459B2 JP 3606459 B2 JP3606459 B2 JP 3606459B2 JP 2001271329 A JP2001271329 A JP 2001271329A JP 2001271329 A JP2001271329 A JP 2001271329A JP 3606459 B2 JP3606459 B2 JP 3606459B2
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JP
Japan
Prior art keywords
sipe
tire
respect
width direction
block
Prior art date
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JP2001271329A
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Japanese (ja)
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JP2003072324A (en
Inventor
稔之 大橋
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Toyo Tire Corp
Original Assignee
Toyo Tire and Rubber Co Ltd
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Priority to JP2001271329A priority Critical patent/JP3606459B2/en
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    • BPERFORMING OPERATIONS; TRANSPORTING
    • B60VEHICLES IN GENERAL
    • B60CVEHICLE TYRES; TYRE INFLATION; TYRE CHANGING; CONNECTING VALVES TO INFLATABLE ELASTIC BODIES IN GENERAL; DEVICES OR ARRANGEMENTS RELATED TO TYRES
    • B60C11/00Tyre tread bands; Tread patterns; Anti-skid inserts
    • B60C11/03Tread patterns
    • B60C11/12Tread patterns characterised by the use of narrow slits or incisions, e.g. sipes
    • B60C11/1204Tread patterns characterised by the use of narrow slits or incisions, e.g. sipes with special shape of the sipe
    • B60C2011/1213Tread patterns characterised by the use of narrow slits or incisions, e.g. sipes with special shape of the sipe sinusoidal or zigzag at the tread surface

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  • Tires In General (AREA)

Description

【0001】
【発明の属する技術分野】
本発明は、波状部分又はジグザグ状部分を含むサイプを形成した複数のブロックを有するトレッドパターンを備えた空気入りタイヤに関し、特にスタッドレスタイヤとして有用である。
【0002】
【従来の技術】
従来より、スタッドレスタイヤのアイス性能を向上させる目的で、タイヤパターンの各部(センター部、メディエイト部、ショルダー部)に数多くのサイプを配置した例が知られている。そして、アイス制動性能を向上させる目的で、タイヤ幅方向に延びるサイプを数多く配置して、前後方向のエッジ効果を向上させてきた。また、アイス旋回性能を向上させる目的で、タイヤ周方向に近づくような角度のサイプ成分を増加させて、横方向のエッジ効果を向上させてきた。
【0003】
このようなアイス制動性能とアイス旋回性能との両者を向上させる方法として、タイヤ幅方向の直線サイプに代えて、波状又はジグザグ状のサイプをタイヤ幅方向に形成することが一般に行われてきた。このような波型サイプ等では、タイヤ幅方向に近い角度の部分に加えて、タイヤ幅方向から約45°に近い角度の部分が存在するため、直線サイプに比べてアイス旋回性能を向上させることができる。
【0004】
しかし、上記の波型サイプ等では、タイヤ幅方向の成分の減少が避けられず、また、タイヤ周方向の成分も約45°の角度では十分とは言えず、アイス制動性能とアイス旋回性能との向上効果がいずれも不十分であった。
【0005】
【発明が解決しようとする課題】
一方、特開2000−94909号公報には、タイヤ幅方向に延びるジグザグ状のサイプの短辺と長辺の比(短辺/長辺)を0.25〜0.75にすると共に、長辺の傾斜角度をタイヤ周方向に対して65〜90°にし、長辺と短辺との交差角度を90〜130°にし、かつ横溝と長辺との傾斜方向を反対にした空気入りタイヤが提案されている。そして、このようなサイプ形成により、アイス制動性能、アイス走行安定性、耐辺摩耗性が改善される旨が開示されている。
【0006】
しかしながら、上記のサイプは、タイヤ幅方向に延びるものであり、短辺の長さが小さく、その角度もタイヤ周方向からのズレを大幅に許容するため、サイプ短辺によるアイス走行安定性の改善効果は殆どないと考えられる。そして、上記公報では、アイス走行安定性の改善効果が、横溝の傾斜方向とサイプ長辺の傾斜方向を反対にしたことによる効果と位置づけている。
【0007】
そこで、本発明の目的は、横方向及び前後方向のエッジ成分が大きく、アイス制動性能とアイス旋回性能の両者の改善効果が大きい空気入りタイヤを提供することにある。
【0008】
【課題を解決するための手段】
上記目的は、下記の如き本発明により達成できる。即ち、本発明は、波状部分を含むサイプを形成した複数のブロックを有するトレッドパターンを備えた空気入りタイヤにおいて、前記サイプは、接線がタイヤ幅方向に対して−20〜20°の角度の第1部分と、接線がタイヤ周方向に対して−20〜20°の角度の第2部分とを、両部分の長さの比率(第1部分/第2部分)が0.9〜1.1になるように、且つ、1周期内にそれぞれ40%以上の長さで含む波状部分を、同一周期で繰り返して形成されたことを特徴とする。
【0010】
また、前記サイプは、その波状部分又はジグザグ状部分の少なくとも一端からブロックの側壁又はその近傍まで延び、方向がタイヤ幅方向に対して−20〜20°の角度の略直線部分を含むことが好ましい。
【0011】
[作用効果]
本発明によると、接線がタイヤ幅方向に対して−20〜20°の角度の第1部分をサイプの1周期内に40%以上の長さで含むため、前後方向のエッジ成分が多くなり、アイス制動性などの前後性能が向上する。また、接線がタイヤ周方向に対して−20〜20°の角度の第2部分をサイプの1周期内に40%以上の長さで含むため、横方向のエッジ成分が多くなり、アイス旋回性が向上する。そして、両部分の長さの比率(第1部分/第2部分)を0.9〜1.1とすることにより、バランス良くアイス制動性能とアイス旋回性能の両者を改善することができる。また、タイヤ幅方向に対して約45°のサイプ成分が少なくなるため、前後力や横力が生じた際にブロック片が開きにくく、ブロック片の倒れ込みが少なくなり、サイプに隣接するブロック片の段差摩耗も生じにくくすることができる。
【0013】
前記サイプは、その波状部分又はジグザグ状部分の少なくとも一端からブロックの側壁又はその近傍まで延び、方向がタイヤ幅方向に対して−20〜20°の角度の略直線部分を含む場合、ブロックの側壁に対する角度が小さくなりにくいため、サイプ端近傍でのブロック片の破損などを起こしにくくすることができる。
【0014】
【発明の実施の形態】
以下、本発明の実施の形態について、図面を参照しながら説明する。図1は、本発明の空気入りタイヤの一例のトレッド面を示す平面図である。また、図2(a)は、図1のトレッド面のブロックを示す要部拡大図であり、図2(b)は、そのサイプの要部拡大図である。
【0015】
本発明の空気入りタイヤは、図1に示すように、波状部分又はジグザグ状部分を含むサイプ10を形成した複数のブロック1を有するトレッドパターンTを備える。本実施形態では、周方向溝2と横溝3とにより区分されて長方形のブロック1が形成され、タイヤセンターCLを対象に5列のブロック1が配列されている例を示す。この例では、各ブロック1におけるサイプ10の方向が、各ブロックごとに逆向きになるように配列されているが、同じ向きで配列されていてもよい。
【0016】
本発明におけるサイプ10は、図2(a)〜(b)に示すように、サイプ10の波状部分11又はジグザグ状部分は、接線がタイヤ幅方向WDに対して−20〜20°の角度の第1部分11aを1周期内に20〜70%の長さで含み、また接線がタイヤ周方向PDに対して−20〜20°の角度の第2部分11bを1周期内に20〜70%の長さで含むことを特徴とする。図2(b)には、ピッチPIに対応する1周期内に、第1部分11aの長さ42%、第2部分11bの長さ42%にて含有するサイプ10が示されている。なお、サイプ10の接線はサイプ中央線を基準として決定する。
【0017】
本発明では、アイス制動性能とアイス旋回性能のバランスを高めながら、両者の性能を一定以上にする上で、第1部分11aの1周期内の長さを40〜60%、第2部分11bの1周期内の長さを40〜60%とするのが好ましい。
【0018】
また、第1部分11aと第2部分11bの長さの比率(第1部分/第2部分)は0.8〜1.2であるのが好ましく、より好ましくは0.9〜1.1である。最も好ましいのは、第1部分11aと第2部分11bの長さの比率を略同じにして、これを同一周期で繰り返すことにより、サイプ10の波状部分11を形成したものである。
【0019】
本発明では、図2に示すような波状部分11を設ける代わりに、ジグザグ状部分を設けてもよいが、屈曲部の耐摩耗性を高める上で、図2に示すようにサイプ10の屈曲部11cが円弧部を有していることが好ましい。また、屈曲部は円弧のみで形成されている必要はなく楕円弧や放物線の一部などでもよい。
【0020】
一方、本実施形態におけるサイプ10は、図2(a)に示すように、波状部分11の少なくとも一端からブロックの側壁又はその近傍まで延び、方向がタイヤ幅方向WDに対して−20〜20°の角度の略直線部分12を含んでいる。
【0021】
また、複数のサイプ10を片側閉塞サイプとして、その閉塞側を左右交互に配置して、ブロック側壁においてサイプ10の解放側と閉塞側とが交互になるようにしている。これによって、ブロック側壁付近でのブロック剛性を維持することで、その部分での偏摩耗を効果的に防止している。
【0022】
図2に示す例では、サイプ10が各ブロック1に対して8本づつ配列してあるが、本発明では各ブロック1に対してサイプ10を複数配列するのが好ましい。このようにサイプ10の本数を増やすことにより、サイプ密度を高めることができるが、サイプ密度は0.1mm/mm 以上が好ましい。
【0023】
複数のサイプ10は、その波状部分11又はジグザグ状部分をその基準方向が略平行になるように配置するのが好ましい。更に、隣接するサイプ10の周期を同期させておくのが好ましい。
【0024】
なお、サイプの深さは1〜8mm程度が好ましく、サイプの溝幅は0.1〜0.5mm程度が好ましい。
【0025】
本発明の空気入りタイヤは、上記の如きトレッドパターンTを備える以外は、通常の空気入りタイヤと同等であり、従来公知の材料、形状、構造、製法などが何れも本発明に採用できる。
【0026】
本発明の空気入りタイヤは、いわゆる夏用タイヤにも適用できるが、前述の如き作用効果を奏するため、特にスタッドレスタイヤとして有用である。
【0027】
[他の実施形態]
以下、本発明の他の実施の形態について説明する。
【0028】
(1)前述の実施形態では、図1〜図2に示すサイプ10が形成されている例を示したが、本発明におけるサイプは、例えば図3(a)〜(c)に示すようなものでもよい。
【0029】
図3(a)に示すサイプ10は、波状部分11から延びるタイヤ幅方向に対して−20〜20°の角度の略直線部分を設けずに、波状部分11のみでサイプ10を形成した例である。この場合おいても、波状部分11の端部がブロック側壁に対して−20〜20°の角度になるようにするのが好ましく、これを達成すべく波状部分11の端部の周期性を若干変更してもよい。
【0030】
図3(b)に示すサイプ10は、図2(a)に示すものに対して全体を少し傾斜させて、若干角度を変化させたものである。その結果、波状部分11又はジグザグ状部分の少なくとも一端からブロックの側壁又はその近傍まで延びる略直線部分12の方向が、タイヤ幅方向に対して略0°となっている。
【0031】
図3(c)に示すサイプ10は、方形波に近い波状部分11又はジグザグ状部分を含むサイプを形成したものである。このような形状のサイプ10でも、接線がタイヤ幅方向に対して−20〜20°の角度の第1部分を1周期内に20〜70%の長さで含み、また接線がタイヤ周方向に対して−20〜20°の角度の第2部分を1周期内に20〜70%の長さで含むことが可能となる。
【0032】
(2)前述の実施形態では、サイプ形状が深さ方向に変化しないものの例を示したが、両者が係合する凹部及び凸部を対向するサイプ内面に形成してもよい。その場合、凹部及び凸部の形状としては、半球状、円錐状、又は角錐状の凹凸などが挙げられる。
【0033】
(3)前述の実施形態では、サイプの基準面がブロック表面に対して垂直になるように形成された例を示したが、ブロック表面の法線に対してサイプの基準面が若干(例えば15°以下)傾斜していてもよい。
【0034】
(4)前述の実施形態では、図1に示すようなブロックパターンの例を示したが、長方形のブロックに限らず、平行四辺形、V字型、5角形、又は曲線基調のブロックでもよい。また、中央付近や端部近傍まで溝の入ったブロックや一部の陸部が周方向に連続するものでもよい。
【0035】
【実施例】
以下、本発明の構成と効果を具体的に示す実施例等について説明する。なお、タイヤの各性能評価は、次のようにして行った。
【0036】
(1)アイス制動性能
タイヤを実車(国産2000ccクラスのFFセダン)に装着し、1名乗車の荷重条件にて、凍結した路面を走行させ、速度40km/hで制動力をかけてフルロックした際の制動距離を指数で評価した。なお、評価は従来品(比較例1)を100としたときの指数表示で示し、数値が大きいほど良好な結果を示す。
【0037】
(2)アイス旋回性能
タイヤを上記と同じ実車に装着し、1名乗車の荷重条件で同じ路面をレムニスケート曲線(8の字曲線:R=25m円)にて走行し、そのラップタイムを指数で評価した。なお、評価は従来品(比較例1)を100としたときの指数表示で示し、数値が大きいほど良好な結果を示す。
【0038】
(3)耐摩耗性能
舗装道路を8000km走行したときの段差摩耗量(摩耗によるサイプ両側のブロック片の段差)を測定し、指数で評価した。なお、評価は従来品(比較例1)を100としたときの指数表示で示し、数値が大きいほど良好な結果を示す。
【0039】
実施例1〜3
図1に示すようなトレッドパターンにおいて、表1のような条件で深さ7mm、幅0.3mm、波状部分の周期2.5mm、振幅2.25mmのサイプを形成してサイズ185/70R14のラジアルタイヤを製造し、上記の各性能評価を行った。その結果を表1に示す。なお、実施例3のサイプは、図3(a)に対応している。
【0040】
比較例1(従来品)
図1に示すようなトレッドパターンにおいて、タイヤ幅方向に延びる従来の波型サイプ(タイヤ幅方向に対して約45°の傾斜部分が主体)を形成してサイズ185/70R14のラジアルタイヤを製造し、上記の各性能評価を行った。その結果を表1に示す。
【0041】
比較例2
実施例1において、表1のようにサイプの第2部分の長さなどを変更すること以外は、実施例1と同様にしてサイズ185/70R14のラジアルタイヤを製造し、上記の各性能評価を行った。その結果を表1に示す。
【0042】
【表1】

Figure 0003606459
表1の結果が示すように、実施例では横方向及び前後方向のエッジ成分が大きいため、アイス制動性能、アイス旋回性能及び耐摩耗性能が従来品と比較して大幅に改善されていた。これに対して、サイプの第2部分の長さが小さい比較例2では、アイス旋回性能の改善効果が殆どなかった。
【図面の簡単な説明】
【図1】本発明の空気入りタイヤの一例のトレッド面を示す平面図
【図2】図1のトレッド面のブロックを示す要部拡大図
【図3】本発明におけるサイプの他の例を示す要部拡大図
【符号の説明】
1 ブロック
10 サイプ
11 サイプの波状部分
11a 第1部分
11b 第2部分
12 略直線部分
PI ピッチ
WD タイヤ幅方向
PD タイヤ周方向[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a pneumatic tire including a tread pattern having a plurality of blocks in which a sipe including a wavy portion or a zigzag portion is formed, and is particularly useful as a studless tire.
[0002]
[Prior art]
Conventionally, in order to improve the ice performance of a studless tire, an example in which a large number of sipes are arranged in each part (center part, mediate part, shoulder part) of a tire pattern is known. For the purpose of improving the ice braking performance, many sipes extending in the tire width direction have been arranged to improve the edge effect in the front-rear direction. For the purpose of improving the ice turning performance, the sipe component having an angle approaching the tire circumferential direction has been increased to improve the lateral edge effect.
[0003]
As a method for improving both the ice braking performance and the ice turning performance, it has been generally performed to form a wave-shaped or zigzag-shaped sipe in the tire width direction instead of the straight sipe in the tire width direction. In such a wave-shaped sipe, in addition to a portion with an angle close to the tire width direction, there is a portion with an angle close to about 45 ° from the tire width direction. Can do.
[0004]
However, in the above-mentioned wave type sipe, etc., the decrease in the component in the tire width direction is unavoidable, and the component in the tire circumferential direction cannot be said to be sufficient at an angle of about 45 °. The improvement effects were not sufficient.
[0005]
[Problems to be solved by the invention]
On the other hand, in JP-A-2000-94909, the ratio of short side to long side (short side / long side) of the zigzag sipe extending in the tire width direction is set to 0.25 to 0.75, and the long side Proposed pneumatic tires with an inclination angle of 65 to 90 ° with respect to the tire circumferential direction, an intersection angle between the long side and the short side of 90 to 130 °, and an inclination direction of the lateral groove and the long side opposite to each other. Has been. And it is disclosed that ice braking performance, ice running stability, and edge wear resistance are improved by such sipe formation.
[0006]
However, the above sipe extends in the tire width direction, the length of the short side is small, and the angle also allows a large deviation from the tire circumferential direction. There seems to be little effect. And in the said gazette, the improvement effect of ice running stability is positioned as the effect by having made the inclination direction of a horizontal groove and the inclination direction of a sipe long side opposite.
[0007]
Therefore, an object of the present invention is to provide a pneumatic tire having large edge components in the lateral direction and the front-rear direction and having a large improvement effect on both ice braking performance and ice turning performance.
[0008]
[Means for Solving the Problems]
The above object can be achieved by the present invention as described below. That is, the present invention relates to a pneumatic tire having a tread pattern having a plurality of blocks each having a sipe including a wavy portion, wherein the sipe has a tangent of -20 to 20 ° with respect to the tire width direction. One portion and a second portion whose tangent is at an angle of -20 to 20 ° with respect to the tire circumferential direction, and the ratio of the lengths of both portions (first portion / second portion) is 0.9 to 1.1. And a wavy portion including a length of 40% or more in one cycle is repeatedly formed in the same cycle.
[0010]
Moreover, it is preferable that the sipe includes a substantially straight portion extending from at least one end of the wavy portion or the zigzag portion to the side wall of the block or the vicinity thereof and having an angle of -20 to 20 ° with respect to the tire width direction. .
[0011]
[Function and effect]
According to the present invention, since the tangent line includes the first portion having an angle of -20 to 20 ° with respect to the tire width direction with a length of 40% or more in one cycle of the sipe, the edge component in the front-rear direction increases. Front and rear performance such as ice braking performance is improved. In addition, since the tangent includes the second portion having an angle of -20 to 20 ° with respect to the tire circumferential direction with a length of 40% or more in one cycle of the sipe, the edge component in the lateral direction is increased, and the ice turning property is increased. Will improve. And both the ice braking performance and ice turning performance can be improved in a well-balanced manner by setting the ratio of the lengths of both portions (first portion / second portion) to 0.9 to 1.1. In addition, since the sipe component of about 45 ° with respect to the tire width direction is reduced, the block piece is difficult to open when a longitudinal force or a lateral force is generated, and the block piece is less likely to fall down. Step wear can also be made difficult to occur.
[0013]
The sipe extends from at least one end of the wavy portion or zigzag portion to the side wall of the block or the vicinity thereof, and when the direction includes a substantially straight portion having an angle of -20 to 20 ° with respect to the tire width direction, the side wall of the block Therefore, it is possible to prevent the block piece from being damaged near the sipe end.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a plan view showing a tread surface of an example of the pneumatic tire of the present invention. 2A is an enlarged view of a main part showing a block of the tread surface of FIG. 1, and FIG. 2B is an enlarged view of a main part of the sipe.
[0015]
As shown in FIG. 1, the pneumatic tire of the present invention includes a tread pattern T having a plurality of blocks 1 each having a sipe 10 including a wavy portion or a zigzag portion. In the present embodiment, an example is shown in which rectangular blocks 1 are formed by being divided by circumferential grooves 2 and lateral grooves 3, and five rows of blocks 1 are arranged for the tire center CL. In this example, the sipes 10 in each block 1 are arranged so that the directions of the sipes 10 are opposite to each other, but they may be arranged in the same direction.
[0016]
In the sipe 10 according to the present invention, as shown in FIGS. 2A to 2B, the wavy portion 11 or the zigzag portion of the sipe 10 has a tangent of -20 to 20 ° with respect to the tire width direction WD. The first portion 11a is included in a length of 20 to 70% in one cycle, and the second portion 11b whose tangent is at an angle of -20 to 20 ° with respect to the tire circumferential direction PD is 20 to 70% in one cycle. It is characterized by including in length. FIG. 2B shows the sipe 10 that is contained in the length 42% of the first portion 11a and the length 42% of the second portion 11b in one period corresponding to the pitch PI. The tangent line of the sipe 10 is determined with reference to the sipe center line.
[0017]
In the present invention, while improving the balance between the ice braking performance and the ice turning performance, while maintaining the performance of both of them at a certain level or more, the length of the first portion 11a in one cycle is 40 to 60%, and the second portion 11b The length within one period is preferably 40 to 60%.
[0018]
The ratio of the length of the first portion 11a and the second portion 11b (first portion / second portion) is preferably 0.8 to 1.2, more preferably 0.9 to 1.1. is there. Most preferably, the wavy portion 11 of the sipe 10 is formed by making the ratio of the lengths of the first portion 11a and the second portion 11b substantially the same and repeating this in the same cycle.
[0019]
In the present invention, a zigzag portion may be provided instead of providing the wavy portion 11 as shown in FIG. 2, but in order to improve the wear resistance of the bent portion, the bent portion of the sipe 10 as shown in FIG. It is preferable that 11c has a circular arc part. Further, the bent portion need not be formed only by an arc, and may be an elliptical arc or a part of a parabola.
[0020]
On the other hand, as shown in FIG. 2A, the sipe 10 in the present embodiment extends from at least one end of the corrugated portion 11 to the side wall of the block or the vicinity thereof, and the direction is -20 to 20 ° with respect to the tire width direction WD. And a substantially straight portion 12 having an angle of.
[0021]
Moreover, the several sipe 10 is made into the one-side obstruction | occlusion sipe, the obstruction | occlusion side is arrange | positioned alternately right and left, and the release side and obstruction | occlusion side of the sipe 10 are made to alternate in a block side wall. Thus, by maintaining the block rigidity in the vicinity of the block side wall, uneven wear at that portion is effectively prevented.
[0022]
In the example shown in FIG. 2, eight sipes 10 are arranged for each block 1. However, in the present invention, it is preferable to arrange a plurality of sipes 10 for each block 1. Thus, the sipe density can be increased by increasing the number of the sipe 10, but the sipe density is preferably 0.1 mm / mm 2 or more.
[0023]
The plurality of sipes 10 are preferably arranged such that the wavy portions 11 or zigzag portions thereof are substantially parallel to each other. Furthermore, it is preferable to synchronize the periods of adjacent sipes 10.
[0024]
The sipe depth is preferably about 1 to 8 mm, and the sipe groove width is preferably about 0.1 to 0.5 mm.
[0025]
The pneumatic tire of the present invention is the same as a normal pneumatic tire except that it includes the tread pattern T as described above, and any conventionally known material, shape, structure, manufacturing method, and the like can be employed in the present invention.
[0026]
The pneumatic tire of the present invention can be applied to so-called summer tires, but is particularly useful as a studless tire because it exhibits the effects as described above.
[0027]
[Other Embodiments]
Hereinafter, other embodiments of the present invention will be described.
[0028]
(1) In the above-described embodiment, an example is shown in which the sipe 10 shown in FIGS. 1 to 2 is formed, but the sipe in the present invention is as shown in FIGS. 3 (a) to 3 (c), for example. But you can.
[0029]
The sipe 10 shown in FIG. 3 (a) is an example in which the sipe 10 is formed only by the undulating portion 11 without providing a substantially straight portion having an angle of −20 to 20 ° with respect to the tire width direction extending from the undulating portion 11. is there. Even in this case, it is preferable that the end of the wavy portion 11 is at an angle of -20 to 20 ° with respect to the block side wall. To achieve this, the periodicity of the end of the wavy portion 11 is slightly changed. It may be changed.
[0030]
The sipe 10 shown in FIG. 3B is obtained by slightly tilting the whole with respect to that shown in FIG. As a result, the direction of the substantially straight portion 12 extending from at least one end of the wavy portion 11 or the zigzag portion to the side wall of the block or the vicinity thereof is substantially 0 ° with respect to the tire width direction.
[0031]
A sipe 10 shown in FIG. 3C is formed by forming a sipe including a wave-like portion 11 or a zigzag-like portion close to a square wave. Even in the sipe 10 having such a shape, the tangent includes a first portion having an angle of -20 to 20 ° with respect to the tire width direction in a length of 20 to 70% in one cycle, and the tangent is in the tire circumferential direction. On the other hand, the second portion having an angle of -20 to 20 ° can be included in a period of 20 to 70%.
[0032]
(2) In the above-described embodiment, an example is shown in which the sipe shape does not change in the depth direction. However, a concave portion and a convex portion that engage with each other may be formed on the sipe inner surface facing each other. In that case, examples of the shape of the concave portion and the convex portion include hemispherical, conical, or pyramidal irregularities.
[0033]
(3) In the above-described embodiment, an example in which the sipe reference plane is formed so as to be perpendicular to the block surface is shown. ° or less) may be inclined.
[0034]
(4) In the above-described embodiment, an example of the block pattern as shown in FIG. 1 is shown. However, the block pattern is not limited to a rectangular block, and may be a parallelogram, V-shaped, pentagonal, or curved block. In addition, a grooved block or a part of land portion may be continuous in the circumferential direction near the center or near the end.
[0035]
【Example】
Examples and the like specifically showing the configuration and effects of the present invention will be described below. In addition, each performance evaluation of the tire was performed as follows.
[0036]
(1) Ice braking performance tires were mounted on a real vehicle (domestic 2000cc class FF sedan), and the vehicle was fully frozen by applying braking force at a speed of 40km / h while running on a frozen road under the load conditions of one passenger. The braking distance was evaluated with an index. In addition, evaluation is shown by an index display when the conventional product (Comparative Example 1) is set to 100, and a larger value indicates a better result.
[0037]
(2) Ice turning performance tires are mounted on the same actual vehicle as above, running on the same road surface under the load conditions of one person riding on the Lemnis skating curve (eight curve: R = 25m yen), and the lap time is evaluated as an index did. In addition, evaluation is shown by an index display when the conventional product (Comparative Example 1) is set to 100, and a larger value indicates a better result.
[0038]
(3) Abrasion resistance performance The amount of step wear when traveling on a paved road for 8000 km (step difference between block pieces on both sides of the sipe due to wear) was measured and evaluated by an index. In addition, evaluation is shown by an index display when the conventional product (Comparative Example 1) is set to 100, and a larger value indicates a better result.
[0039]
Examples 1-3
In the tread pattern as shown in FIG. 1, a sipe having a depth of 7 mm, a width of 0.3 mm, a wavy portion period of 2.5 mm, and an amplitude of 2.25 mm is formed under the conditions shown in Table 1, and a radial of size 185 / 70R14. A tire was manufactured and each performance evaluation was performed. The results are shown in Table 1. In addition, the sipe of Example 3 respond | corresponds to Fig.3 (a).
[0040]
Comparative example 1 (conventional product)
In the tread pattern as shown in FIG. 1, a conventional corrugated sipe extending mainly in the tire width direction (mainly an inclined portion of about 45 ° with respect to the tire width direction) is formed to produce a radial tire of size 185 / 70R14. Each of the above performance evaluations was performed. The results are shown in Table 1.
[0041]
Comparative Example 2
In Example 1, a radial tire of size 185 / 70R14 was manufactured in the same manner as in Example 1 except that the length of the second part of the sipe was changed as shown in Table 1, and the above performance evaluations were performed. went. The results are shown in Table 1.
[0042]
[Table 1]
Figure 0003606459
As shown in the results of Table 1, in the examples, the edge components in the lateral direction and the front-rear direction are large, so that the ice braking performance, the ice turning performance, and the wear resistance performance are greatly improved as compared with the conventional product. On the other hand, in Comparative Example 2 in which the length of the second part of the sipe was small, there was almost no effect of improving the ice turning performance.
[Brief description of the drawings]
FIG. 1 is a plan view showing a tread surface of an example of a pneumatic tire of the present invention. FIG. 2 is an enlarged view of a main part showing a block of the tread surface of FIG. 1. FIG. 3 shows another example of a sipe in the present invention. Enlarged view of main parts [Explanation of symbols]
1 block 10 sipe 11 sipe wavy portion 11a first portion 11b second portion 12 substantially straight portion PI pitch WD tire width direction PD tire circumferential direction

Claims (2)

波状部分を含むサイプを形成した複数のブロックを有するトレッドパターンを備えた空気入りタイヤにおいて、
前記サイプは、接線がタイヤ幅方向に対して−20〜20°の角度の第1部分と、接線がタイヤ周方向に対して−20〜20°の角度の第2部分とを、両部分の長さの比率(第1部分/第2部分)が0.9〜1.1になるように、且つ、1周期内にそれぞれ40%以上の長さで含む波状部分を、同一周期で繰り返して形成されたことを特徴とする空気入りタイヤ。
In a pneumatic tire provided with a tread pattern having a plurality of blocks formed with sipes including wavy portions,
The sipe includes a first portion having a tangent angle of -20 to 20 ° with respect to the tire width direction and a second portion having a tangent angle of -20 to 20 ° with respect to the tire circumferential direction. Repeating the wavy portions including the length ratio (first portion / second portion) of 0.9 to 1.1 with a length of 40% or more in one cycle in the same cycle A pneumatic tire characterized by being formed.
前記サイプは、その波状部分の少なくとも一端からブロックの側壁又はその近傍まで延び、方向がタイヤ幅方向に対して−20〜20°の角度の略直線部分を含む請求項1記載の空気入りタイヤ。2. The pneumatic tire according to claim 1, wherein the sipe extends from at least one end of the wavy portion to a side wall of the block or the vicinity thereof, and includes a substantially straight portion whose direction is -20 to 20 ° with respect to the tire width direction.
JP2001271329A 2001-09-07 2001-09-07 Pneumatic tire Expired - Lifetime JP3606459B2 (en)

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