JP2754227B2 - Pneumatic tire - Google Patents
Pneumatic tireInfo
- Publication number
- JP2754227B2 JP2754227B2 JP1007325A JP732589A JP2754227B2 JP 2754227 B2 JP2754227 B2 JP 2754227B2 JP 1007325 A JP1007325 A JP 1007325A JP 732589 A JP732589 A JP 732589A JP 2754227 B2 JP2754227 B2 JP 2754227B2
- Authority
- JP
- Japan
- Prior art keywords
- rubber layer
- groove
- tire
- pneumatic tire
- rubber
- 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 - Lifetime
Links
- 238000005187 foaming Methods 0.000 claims description 17
- 239000011248 coating agent Substances 0.000 claims description 5
- 238000000576 coating method Methods 0.000 claims description 5
- 239000010410 layer Substances 0.000 description 74
- 230000000052 comparative effect Effects 0.000 description 6
- 230000000694 effects Effects 0.000 description 6
- 208000035874 Excoriation Diseases 0.000 description 5
- 238000005299 abrasion Methods 0.000 description 5
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 4
- 239000011247 coating layer Substances 0.000 description 3
- 238000004073 vulcanization Methods 0.000 description 3
- 238000005452 bending Methods 0.000 description 2
- 150000001875 compounds Chemical class 0.000 description 1
- 230000007423 decrease Effects 0.000 description 1
- 230000008034 disappearance Effects 0.000 description 1
- 239000004088 foaming agent Substances 0.000 description 1
- 238000010438 heat treatment Methods 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 238000005259 measurement Methods 0.000 description 1
- 239000007790 solid phase Substances 0.000 description 1
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B60—VEHICLES IN GENERAL
- B60C—VEHICLE TYRES; TYRE INFLATION; TYRE CHANGING; CONNECTING VALVES TO INFLATABLE ELASTIC BODIES IN GENERAL; DEVICES OR ARRANGEMENTS RELATED TO TYRES
- B60C11/00—Tyre tread bands; Tread patterns; Anti-skid inserts
- B60C11/03—Tread patterns
- B60C11/13—Tread patterns characterised by the groove cross-section, e.g. for buttressing or preventing stone-trapping
- B60C11/1307—Tread patterns characterised by the groove cross-section, e.g. for buttressing or preventing stone-trapping with special features of the groove walls
- B60C11/1346—Tread patterns characterised by the groove cross-section, e.g. for buttressing or preventing stone-trapping with special features of the groove walls covered by a rubber different from the tread rubber
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B60—VEHICLES IN GENERAL
- B60C—VEHICLE TYRES; TYRE INFLATION; TYRE CHANGING; CONNECTING VALVES TO INFLATABLE ELASTIC BODIES IN GENERAL; DEVICES OR ARRANGEMENTS RELATED TO TYRES
- B60C11/00—Tyre tread bands; Tread patterns; Anti-skid inserts
- B60C11/0041—Tyre tread bands; Tread patterns; Anti-skid inserts comprising different tread rubber layers
- B60C11/005—Tyre tread bands; Tread patterns; Anti-skid inserts comprising different tread rubber layers with cap and base layers
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B60—VEHICLES IN GENERAL
- B60C—VEHICLE TYRES; TYRE INFLATION; TYRE CHANGING; CONNECTING VALVES TO INFLATABLE ELASTIC BODIES IN GENERAL; DEVICES OR ARRANGEMENTS RELATED TO TYRES
- B60C11/00—Tyre tread bands; Tread patterns; Anti-skid inserts
- B60C11/03—Tread patterns
- B60C11/12—Tread patterns characterised by the use of narrow slits or incisions, e.g. sipes
- B60C11/1204—Tread patterns characterised by the use of narrow slits or incisions, e.g. sipes with special shape of the sipe
- B60C2011/1231—Tread patterns characterised by the use of narrow slits or incisions, e.g. sipes with special shape of the sipe being shallow, i.e. sipe depth of less than 3 mm
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B60—VEHICLES IN GENERAL
- B60C—VEHICLE TYRES; TYRE INFLATION; TYRE CHANGING; CONNECTING VALVES TO INFLATABLE ELASTIC BODIES IN GENERAL; DEVICES OR ARRANGEMENTS RELATED TO TYRES
- B60C11/00—Tyre tread bands; Tread patterns; Anti-skid inserts
- B60C11/03—Tread patterns
- B60C11/12—Tread patterns characterised by the use of narrow slits or incisions, e.g. sipes
- B60C11/1272—Width of the sipe
- B60C2011/1277—Width of the sipe being narrow, i.e. less than 0.3 mm
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B60—VEHICLES IN GENERAL
- B60C—VEHICLE TYRES; TYRE INFLATION; TYRE CHANGING; CONNECTING VALVES TO INFLATABLE ELASTIC BODIES IN GENERAL; DEVICES OR ARRANGEMENTS RELATED TO TYRES
- B60C11/00—Tyre tread bands; Tread patterns; Anti-skid inserts
- B60C11/14—Anti-skid inserts, e.g. vulcanised into the tread band
- B60C2011/147—Foamed rubber or sponge rubber on the tread band
Landscapes
- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Tires In General (AREA)
Description
【発明の詳細な説明】 産業上の利用分野 この発明は、特に冬期の氷雪路面上における駆動性
能、制動性能、操縦性能等の氷雪性能を向上させた空気
入りタイヤに関する。Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pneumatic tire having improved ice and snow performance, such as driving performance, braking performance, and steering performance, particularly on ice and snowy road surfaces in winter.
従来の技術 従来、前述したような氷雪性能が良好な空気入りタイ
ヤとしては、例えば発泡ゴムをトレッドに用いた空気入
りタイヤが知られており、このような空気入りタイヤ
は、氷雪面上に存在している水分を接地時に気泡内に吸
込んで氷雪面を直接露出させ、これにより、氷雪性能を
向上させるようにしている。2. Description of the Related Art Conventionally, as a pneumatic tire having good ice and snow performance as described above, for example, a pneumatic tire using a foamed rubber as a tread is known, and such a pneumatic tire exists on an ice and snow surface. When the ground is in contact with the water, the moisture is sucked into the bubbles to directly expose the ice and snow surface, thereby improving the ice and snow performance.
発明が解決しようとする課題 しかしながら、このような空気入りタイヤにあって
は、発泡ゴム内に存在する各々の気泡が応力集中核とな
り易く、ゴムの耐引き裂き性が低くなっているため、細
溝底や細溝端等の繰り返し応力が働く部位で亀裂が発
生、伝幡し易いという問題点がある。Problems to be Solved by the Invention However, in such a pneumatic tire, each air bubble present in the foamed rubber tends to become a stress concentration nucleus, and the tear resistance of the rubber is low, so that the narrow groove is formed. There is a problem that a crack is generated in a portion where a repeated stress acts, such as a bottom or a narrow groove end, and propagation is easy.
課題を解決するための手段 このような問題点を解決するため、本出願人は鋭意研
究を重ね、特願昭63−146649号（昭和63年６月13日出
願）において溝底等の亀裂を効果的に阻止することがで
きる空気入りタイヤを提案した。Means for Solving the Problems In order to solve such problems, the present applicant has conducted intensive studies and found cracks such as groove bottoms in Japanese Patent Application No. 63-146649 (filed on June 13, 1988). A pneumatic tire that can be effectively blocked has been proposed.
その空気入りタイヤは、半径方向外方に位置する外側
ゴム層および内方に位置する内側ゴム層の少なくとも２
層のゴム層からなるトレッドを有し、該トレッドの少な
くとも一部分にブロック状の陸部を形成する複数の溝を
有する空気入りタイヤにおいて、前記内側ゴム層はショ
アーＡ硬度が54゜〜80゜でかつ前記外側ゴム層に比して
より高く、前記外側ゴム層は発泡率Ｖが５％〜50％の範
囲の発泡ゴムからなり前記トレッドの体積に占める割合
は少なくとも10％であり、前記外側ゴム層の外表面が外
側ゴム層の発泡ゴムの発泡率より小さいゴムシートから
なる厚さ1mm以下の被覆層により被覆されてなる空気入
りタイヤである。The pneumatic tire has at least two outer rubber layers located radially outward and an inner rubber layer located inward.
A pneumatic tire having a plurality of grooves forming a block-like land portion in at least a part of the tread, wherein the inner rubber layer has a Shore A hardness of 54 ° to 80 °. The outer rubber layer is higher than the outer rubber layer, and the outer rubber layer is made of foamed rubber having a foaming ratio V in a range of 5% to 50%, and a proportion of the volume of the tread is at least 10%; A pneumatic tire in which the outer surface of the layer is covered with a coating layer having a thickness of 1 mm or less made of a rubber sheet having a foaming rate smaller than that of the foamed rubber of the outer rubber layer.
しかしながら、このような空気入りタイヤは、発泡ゴ
ムからなる外側ゴム層の外表面を、発泡率の低い、一般
には無発泡の通常ゴムからなる被覆層により被覆してい
るので、摩耗の極く初期において、即ち被覆層が摩耗で
消失するまでの間、滑らかな表面が露出し、この結果、
氷雪面上に存在している水分を充分に排除することがで
きなくなって氷雪性能が低下してしまうという問題点が
ある。However, in such a pneumatic tire, since the outer surface of the outer rubber layer made of foamed rubber is covered with a coating layer made of a low-foaming, generally non-foamed, normal rubber, the wear is extremely low in the initial stage. In, that is, until the coating layer disappears by abrasion, a smooth surface is exposed, and as a result,
There is a problem that the water existing on the ice and snow surface cannot be sufficiently removed and the ice and snow performance is reduced.
このため、本出願人は鋭意研究を重ね、以下のような
空気入りタイヤを案出した。For this reason, the present applicant has conducted intensive studies and devised the following pneumatic tires.
即ち、半径方向外方に位置する外側ゴム層および半径
方向内方に位置する内側ゴム層の少なくとも２層のゴム
層からなり、その表面に溝および陸部が形成されたトレ
ッドを有する空気入りタイヤにおいて、前記内側ゴム層
をショアーＡ硬度が外側ゴム層のショアーＡ硬度より高
いゴムから構成するとともに、前記外側ゴム層を発泡ゴ
ムから構成し、かつ、前記外側ゴム層の表面を発泡率が
外側ゴム層の発泡率より小さいゴムからなる被覆ゴム層
により被覆するとともに、前記陸部表面に溝深さが4.5m
m以下の多数の細溝を形成した空気入りタイヤである。That is, a pneumatic tire including a tread having at least two rubber layers, an outer rubber layer positioned radially outward and an inner rubber layer positioned radially inward, and having grooves and land portions formed on the surface thereof. In the above, the inner rubber layer is composed of rubber having a Shore A hardness higher than the Shore A hardness of the outer rubber layer, the outer rubber layer is composed of foamed rubber, and the surface of the outer rubber layer has a foaming rate of outside. While covered with a covering rubber layer made of rubber smaller than the foaming rate of the rubber layer, the land portion surface has a groove depth of 4.5 m.
This is a pneumatic tire having a large number of narrow grooves of not more than m.
ここで、前記細溝の溝深さを1.0mm以上とするとよ
い。Here, it is preferable that the depth of the narrow groove is 1.0 mm or more.
作用 今、この発明の空気入りタイヤが氷雪面上を走行し、
また、この空気入りタイヤの最外層には摩耗の極く初期
であるため、被覆ゴム層が残存しているとする。ここ
で、被覆ゴム層はその発泡率が外側ゴム層の発泡率より
小さいゴムから構成されているため、前述のように被覆
ゴム層が残存していると、氷雪面上に存在している水分
を充分に排除することができないと考えられるが、この
発明のように陸部表面に多数の細溝を形成すれば、これ
ら細溝が路面接地域に到達したとき、氷雪面上の水分を
効果的に排除することができる。その理由は、水分が細
溝内に毛細管現象により吸上げられて貯込まれるととも
に、細溝の開口エッジによって掻き除かれるからである
と考えられる。この結果、前述したような被覆ゴム層に
より被覆された空気入りタイヤであっても、摩耗の極く
初期における氷雪性能を良好なものとすることができ
る。ここで、細溝の溝深さが4.5mmを超えると、トレッ
ドの陸部の曲げ剛性が低下して摩耗が促進してしまうの
で、細溝の溝深さは4.5mm以下でなければならない。そ
して、このような被覆ゴム層が摩耗により全て消失する
と外側ゴム層が露出するが、このときには外側ゴム層の
外表面に露出している気泡に吸込まれて水分が氷雪面上
から排除される。Now, the pneumatic tire of the present invention runs on ice and snow,
It is also assumed that the outermost layer of the pneumatic tire is in the very early stage of abrasion, so that the covering rubber layer remains. Here, since the covering rubber layer is made of rubber whose foaming rate is smaller than the foaming rate of the outer rubber layer, if the covering rubber layer remains as described above, the moisture existing on the ice and snow surface However, if a large number of narrow grooves are formed on the land surface as in the present invention, when these narrow grooves reach the road contact area, the moisture on the ice and snow surface is effectively prevented. Can be eliminated. It is considered that the reason is that moisture is sucked up and stored in the narrow groove by capillary action, and is removed by the opening edge of the narrow groove. As a result, even in the case of the pneumatic tire covered with the covering rubber layer as described above, the ice and snow performance in the very early stage of wear can be improved. Here, if the groove depth of the narrow groove exceeds 4.5 mm, the bending rigidity of the land portion of the tread is reduced and wear is promoted. Therefore, the groove depth of the narrow groove must be 4.5 mm or less. Then, when such a coated rubber layer is completely lost due to abrasion, the outer rubber layer is exposed. At this time, moisture is removed from the ice and snow surface by being sucked into bubbles exposed on the outer surface of the outer rubber layer.
また、前述のように細溝の溝深さを1.0mm以上とすれ
ば、前述の効果を確実に発揮することができるが、1.0m
m未満であると、前記効果が弱くなる。Further, when the groove depth of the narrow groove is set to 1.0 mm or more as described above, the above-described effect can be surely exhibited.
If it is less than m, the effect is weakened.
実施例 以下、この発明の一実施例を図面に基づいて説明す
る。Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
第１図において、１は空気入りタイヤであり、このタ
イヤ１はトロイダル状をした少なくとも１層のカーカス
プライ２からなるカーカス層３と、このカーカス層３の
半径方向外側に配置され、少なくとも１層、この実施例
では３層のベルトプライ４からなるベルト層５と、この
ベルト層５の半径方向外側に配置されたトレッド６と、
を有する。前記トレッド６はタイヤ１の半径方向外方に
位置する外側ゴム層11と、半径方向内方に位置する内側
ゴム層12と、の少なくとも２層のゴム層から構成されて
いる。前記外側ゴム層11は発泡率Ｖが５％〜50％の範囲
の発泡ゴムから構成するとともに、前記トレッド６の体
積に占める割合を少なくとも10％としている。ここで、
外側ゴム層11に用いる発泡ゴムは、通常のゴム配合物に
発泡剤を加えて通常のタイヤ製造方法に従って加熱、加
圧することにより形成される。また、前述のように外側
ゴム層11の発泡率Ｖを５％〜50％の範囲としたのは、５
％未満では低温時の発泡ゴムの柔軟性が得られず、ま
た、50％を超えると耐摩耗性能が低下して氷雪路面、湿
潤路面以外の乾燥路面での耐摩耗性が実用的に不充分で
あるからである。ここで、発泡ゴムの発泡率Ｖは次式 Ｖ＝（a/b−１）×100（％） で表すことができる。上記式において、ａは発泡ゴムの
ゴム固相部の密度（g/Cm2）、ｂは発泡ゴムの密度（g/C
m2）である。さらに、前記外側ゴム層11のトレッド６の
体積に占める割合を少なくとも10％としたのは、10％未
満であると氷雪性能の改良効果が少ないためである。一
方、前記内側ゴム層12は、ショアーＡ硬度が前記外側ゴ
ム層11のショアーＡ硬度より高く、かつ、その発泡率が
前記外側ゴム層11の発泡率より小さい（発泡率が零の無
発泡ゴムでもよい）ゴムから構成している。ここで、前
述のように内側ゴム層12のショアーＡ硬度を外側ゴム層
11のショアーＡ硬度より高くすれば、前述したような加
硫圧力の除去時における外側ゴム層11（発泡ゴム）の膨
張を抑制することができ、これにより、トレッド６に形
成された溝の幅が狭小化するのを抑制することができ
る。ここで、この内側ゴム層12のショアーＡ硬度は54度
〜80度の範囲内であることが好ましい。その理由は54度
未満であると、前記溝幅の変化を抑制する効果が小さ
く、一方、80度を超えると氷雪性能が低下するからであ
る。そして、これらトレッド６の表面には主溝、横溝等
の接地時に閉じることのない幅広の広溝16が形成され、
これら広溝16によりトレッド６の表面にはブロック、リ
ブ、ラグ等の陸部18が画成される。また、この陸部18の
表面にはサイプ等の接地時に閉じる幅狭の狭溝17が複数
本形成されている。この実施例では、前記広溝16は外側
ゴム層11を貫通して内側ゴム層12の厚さ方向中央部まで
到達し、一方、狭溝17は内側ゴム層12の外表面近傍まで
到達している。前記トレッド６の表面、詳しくは外側ゴ
ム層11の表面（広溝16、狭溝17の表面も含む）は発泡率
が外側ゴム層１の発泡率より小さいゴムからなる（発泡
率は零でもよい）被覆ゴム層21により被覆されている。
ここで、被覆ゴム層21の厚さは、前記狭溝17の溝底を亀
裂が生じない程度に強化する厚さとする。また、この外
側ゴム層21を含む陸部18の表面にはタイヤ１の軸線方向
と略平行な多数の細溝22が形成され、これらの細溝22
は、例えばナイフカットあるいは加硫モールドの内面に
設けられた多数の薄肉ブレードにより形成される。ここ
で、細溝22の溝幅を狭くするほど路面接地域における接
地圧が均一となるため、細溝22は薄肉ブレードで形成す
るよりナイフカットで形成するほうがよい。そして、こ
れら細溝22はその溝深さＤが4.5mm以下でなければなら
ない。その理由は、細溝22の溝深さＤが4.5mmを超える
と、トレッド６の陸部18の曲げ剛性が低下して摩耗が促
進してしまうからである。また、この細溝22の溝深さＤ
は1.0mm以上であることが好ましい。その理由は、1.0mm
未満であると、溝深さＤが浅過ぎて氷雪面上の水分を排
除する効果が弱くなるからである。さらに、前記細溝22
の溝深さＤは、被覆ゴム層21の厚さＴの80％から120％
の範囲内であることがさらに好ましい。その理由は、80
％未満であると、細溝22が被覆ゴム層21と共に消失した
後、若干の期間滑らかな表面が露出して氷雪性能が低下
するからであり、一方、120％を超えると、細溝22の溝
底が発泡ゴムからなる外側ゴム層11に達し、亀裂発生の
おそれがあるからである。また、この細溝22は溝底23か
ら溝開口24に向かうに従い、即ち、半径方向外側に向か
いに従い回転方向前方へ傾斜していることが好ましい。
このように細溝22の延在方向をトレッド６の表面の垂線
Ｓに対して角度ａだけ回転方向前方へ傾斜させてやる
と、制動力を受けたとき、陸部18が変形して路面接地域
の接地面積が増大し、制動性能が向上する。In FIG. 1, reference numeral 1 denotes a pneumatic tire. The tire 1 has a carcass layer 3 composed of at least one carcass ply 2 having a toroidal shape, and at least one carcass layer 3 disposed radially outside the carcass layer 3. In this embodiment, a belt layer 5 including three belt plies 4, a tread 6 disposed radially outside the belt layer 5,
Having. The tread 6 is composed of at least two rubber layers: an outer rubber layer 11 located radially outward of the tire 1 and an inner rubber layer 12 located radially inward. The outer rubber layer 11 is made of a foamed rubber having a foaming ratio V in the range of 5% to 50%, and the ratio of the tread 6 to the volume is at least 10%. here,
The foamed rubber used for the outer rubber layer 11 is formed by adding a foaming agent to a usual rubber compound, and heating and pressurizing according to a usual tire manufacturing method. Further, as described above, the foaming ratio V of the outer rubber layer 11 is set in the range of 5% to 50%.
If it is less than 50%, the flexibility of the foamed rubber at low temperature cannot be obtained, and if it exceeds 50%, the abrasion resistance is deteriorated, and the abrasion resistance on dry road surfaces other than ice and snow road surfaces and wet road surfaces is practically insufficient. Because it is. Here, the foaming rate V of the foamed rubber can be represented by the following equation: V = (a / b-1) × 100 (%). In the above formula, a is the density of the rubber solid phase portion of the foamed rubber (g / Cm 2 ), and b is the density of the foamed rubber (g / Cm 2 ).
m 2 ). Furthermore, the reason that the ratio of the outer rubber layer 11 to the volume of the tread 6 is at least 10% is that if it is less than 10%, the effect of improving the ice and snow performance is small. On the other hand, the inner rubber layer 12 has a Shore A hardness higher than the Shore A hardness of the outer rubber layer 11 and a foaming rate smaller than that of the outer rubber layer 11 (a non-foamed rubber having a foaming rate of zero). It may be made of rubber. Here, as described above, the Shore A hardness of the inner rubber
When the hardness is higher than the Shore A hardness of 11, the expansion of the outer rubber layer 11 (foamed rubber) at the time of removing the vulcanization pressure as described above can be suppressed, and thereby, the width of the groove formed in the tread 6 can be reduced. Can be suppressed from becoming narrower. Here, the Shore A hardness of the inner rubber layer 12 is preferably in the range of 54 to 80 degrees. The reason is that if it is less than 54 degrees, the effect of suppressing the change in the groove width is small, while if it exceeds 80 degrees, the ice and snow performance is reduced. On the surface of these treads 6, wide grooves 16 such as main grooves, lateral grooves, etc., which are not closed at the time of contact with the ground, are formed.
Lands 18 such as blocks, ribs and lugs are defined on the surface of the tread 6 by these wide grooves 16. A plurality of narrow grooves 17 are formed on the surface of the land portion 18 so as to be closed when the sipe or the like touches the ground. In this embodiment, the wide groove 16 penetrates through the outer rubber layer 11 and reaches the center in the thickness direction of the inner rubber layer 12, while the narrow groove 17 reaches near the outer surface of the inner rubber layer 12. I have. The surface of the tread 6, more specifically, the surface of the outer rubber layer 11 (including the surfaces of the wide groove 16 and the narrow groove 17) is made of rubber having a foaming rate smaller than that of the outer rubber layer 1 (the foaming rate may be zero). ) It is covered with the covering rubber layer 21.
Here, the thickness of the covering rubber layer 21 is set to a thickness that reinforces the groove bottom of the narrow groove 17 to such an extent that cracks do not occur. On the surface of the land portion 18 including the outer rubber layer 21, a number of narrow grooves 22 substantially parallel to the axial direction of the tire 1 are formed.
Is formed by, for example, a number of thin blades provided on the inner surface of a knife cut or vulcanization mold. Here, the narrower the groove width of the narrow groove 22, the more uniform the ground contact pressure in the road contact area, and therefore, it is better to form the narrow groove 22 with a knife cut than with a thin blade. These grooves 22 must have a groove depth D of 4.5 mm or less. The reason for this is that if the groove depth D of the narrow groove 22 exceeds 4.5 mm, the bending rigidity of the land portion 18 of the tread 6 is reduced and wear is accelerated. The groove depth D of the narrow groove 22
Is preferably 1.0 mm or more. The reason is 1.0mm
If it is less than this, the groove depth D is too shallow and the effect of removing moisture on the ice and snow surface is weakened. Further, the narrow groove 22
Is 80% to 120% of the thickness T of the covering rubber layer 21.
Is more preferably within the range. The reason is 80
%, The fine groove 22 disappears together with the covering rubber layer 21 and then the smooth surface is exposed for a short period of time, and the ice and snow performance is reduced. On the other hand, when the fine groove 22 exceeds 120%, the fine groove 22 This is because the groove bottom reaches the outer rubber layer 11 made of foamed rubber, and there is a possibility that cracks may occur. Further, it is preferable that the narrow groove 22 is inclined forward in the rotation direction as it goes from the groove bottom 23 toward the groove opening 24, that is, toward the outside in the radial direction.
As described above, when the extending direction of the narrow groove 22 is inclined forward in the rotation direction by the angle a with respect to the perpendicular S of the surface of the tread 6, when receiving a braking force, the land portion 18 is deformed to contact the road surface. The contact area of the area is increased, and the braking performance is improved.
次に、この発明の一実施例の作用について説明する。 Next, the operation of the embodiment of the present invention will be described.
今、前述したようなタイヤ１によって。氷雪面上を走
行しているとする。このとき、外側ゴム層11および内側
ゴム層12を前述したようなゴムから構成したので、陸部
18の剛性が向上して広溝16、狭溝17の溝幅の変化が抑制
され、この結果、これら広溝16、狭溝17の溝底の曲率半
径が好適な値に維持されて、溝底の動的歪が小さくな
る。しかも、外側ゴム層11の表面を被覆ゴム層21によっ
て被覆したので、広溝16、狭溝17の表面の強度が大きく
なり、特に狭溝17の溝底における亀裂の発生が阻止され
る。また、前述したようなタイヤ１の走行が摩耗の極く
初期である場合には、被覆ゴム層21が外側ゴム層11の表
面を被覆した状態で残存しているが、この被覆ゴム層21
はその発泡率が外側ゴム層11の発泡率より小さいゴムか
ら構成されているため、トレッド６の表面が滑らかとな
って氷雪面上での制動性能が低下すると考えられる。し
かしながら、この実施例においては、前述のように陸部
18の表面に多数の細溝22を形成しているので、これら細
溝22が路面接地域に到達したとき、氷雪面上に存在して
いる水分を排除し、これにより氷雪性能は良好となる。
ここで、前述のように水分が排除できるのは、水分が細
溝内に毛細管現象により吸上げられて貯込まれるととも
に、細溝の開口エッジによって掻き除かれるからである
と考えられている。そして、前記被覆ゴム層21が全て消
失し、外側ゴム層11が露出すると、該外側ゴム層11内に
気泡が氷雪面上の水分を吸込んで排除し、本来の氷雪面
上での性能を発揮する。Now, with tire 1 as described above. Suppose you are traveling on ice and snow. At this time, since the outer rubber layer 11 and the inner rubber layer 12 were made of the above-described rubber,
The rigidity of 18 is improved, and the change in the groove width of the wide groove 16 and the narrow groove 17 is suppressed.As a result, the radius of curvature of the bottom of the wide groove 16 and the narrow groove 17 is maintained at a suitable value, Bottom dynamic strain is reduced. Moreover, since the surface of the outer rubber layer 11 is covered with the coating rubber layer 21, the strength of the surface of the wide groove 16 and the narrow groove 17 is increased, and the generation of cracks at the bottom of the narrow groove 17 is particularly prevented. When the running of the tire 1 as described above is very early in wear, the covering rubber layer 21 remains in a state of covering the surface of the outer rubber layer 11.
It is considered that, since is formed of rubber whose foaming ratio is smaller than the foaming ratio of the outer rubber layer 11, the surface of the tread 6 becomes smooth and the braking performance on the ice and snow surface decreases. However, in this embodiment, the land
Since a large number of narrow grooves 22 are formed on the surface of 18, when these narrow grooves 22 reach the road contact area, moisture existing on the ice and snow surface is eliminated, thereby improving the ice and snow performance .
Here, it is considered that the reason why the water can be removed as described above is that the water is sucked up and stored in the narrow groove by capillary action and is scraped off by the opening edge of the narrow groove. When the coating rubber layer 21 is completely lost and the outer rubber layer 11 is exposed, air bubbles in the outer rubber layer 11 absorb and remove moisture on the ice and snow surface, and exhibit the original performance on the ice and snow surface. I do.
次に、試験例を説明する。この試験にあたっては、比
較タイヤと、この発明を実施した供試タイヤ１および供
試タイヤ２と、を準備した。ここで、比較タイヤは、第
２、３図に示すように、トレッド６を外側ゴム層11およ
び内側ゴム層12の２層のゴム層から構成するとともに、
該トレッド６に広溝16として溝深さが20mmである３本の
主溝および複数本の横溝を形成し、矩形をした複数のブ
ロック状陸部18を画成している。また、各ブロック状陸
部18の表面は深さが10mmで周方向に等距離離れた軸方向
に延びる３本の狭溝17を形成するとともに、前記外側ゴ
ム層11の表面を、厚さＴが2.5mmに無発泡ゴムからなる
被覆ゴム層21によって被覆している。また、前記供試タ
イヤ１は第１、４図に示すように、前記比較タイヤにお
けるブロック状陸部18の表面に、狭溝17と平行な８本の
細溝22をナイフカットによりさらに形成したタイヤであ
る。ここで、各細溝22の深さは、2.5mmであり、前記垂
線Ｓに対する傾斜角ａは20度である。なお、他の構成は
前記比較タイヤと同様である。さらに、前記供試タイヤ
２は、第５図に示すように、細溝22をナイフカットでは
なく加硫モールドの内面に設けた多数の薄肉ブレードに
よって形成するようにしたタイヤであり、この供試タイ
ヤ２の他の構成は前記供試タイヤ１と同一である。ここ
で、各タイヤのサイズは10.00R20であった。次に、この
ような各タイヤを車両に装着した後、該タイヤに正規荷
重を負荷しながら氷上において時速20Km/hで走行してい
るときに急ブレーキをかけ、該ブレーキをかけた地点か
ら停止した地点までの距離を測定した。その測定結果の
逆数を指数で示すと、比較タイヤにあっては100であっ
たが、供試タイヤ１では128、供試タイヤ２では123であ
った。また、前記供試タイヤ１、２における細溝22の垂
線Ｓに対する傾斜角ａを０度とした供試タイヤ３、４を
用いて前述と同様の試験を行なったところ、供試タイヤ
３では126、供試タイヤ４では121であった。ここで、指
数100での制動距離は40mであった。このように本発明を
適用とした空気入りタイヤは、摩耗の極く初期において
も充分な氷雪性能を得ることができる。Next, test examples will be described. In this test, a comparative tire and a test tire 1 and a test tire 2 embodying the present invention were prepared. Here, in the comparative tire, as shown in FIGS. 2 and 3, the tread 6 is composed of two rubber layers, an outer rubber layer 11 and an inner rubber layer 12.
In the tread 6, three main grooves having a groove depth of 20 mm and a plurality of lateral grooves are formed as wide grooves 16 to define a plurality of rectangular block-shaped land portions. The surface of each block-shaped land portion 18 has three narrow grooves 17 which are 10 mm in depth and extend in the axial direction at equal distances in the circumferential direction, and the surface of the outer rubber layer 11 has a thickness T. Is covered with a covering rubber layer 21 made of non-foamed rubber to 2.5 mm. As shown in FIGS. 1 and 4, the test tire 1 further has eight narrow grooves 22 parallel to the narrow grooves 17 formed on the surface of the block-shaped land portion 18 of the comparative tire by knife cutting. Tires. Here, the depth of each narrow groove 22 is 2.5 mm, and the inclination angle a with respect to the perpendicular S is 20 degrees. The other configuration is the same as that of the comparative tire. Further, as shown in FIG. 5, the test tire 2 is a tire in which the narrow groove 22 is formed not by knife cutting but by a large number of thin blades provided on the inner surface of the vulcanization mold. Other configurations of the tire 2 are the same as those of the test tire 1. Here, the size of each tire was 10.00R20. Next, after each such tire is mounted on the vehicle, a sudden brake is applied when the vehicle is running on ice at a speed of 20 km / h while applying a regular load to the tire, and the vehicle stops at the point where the brake is applied. The distance to the point was measured. When the reciprocal of the measurement result was indicated by an index, it was 100 for the comparative tire, but was 128 for the test tire 1 and 123 for the test tire 2. The same test as described above was performed using the test tires 3 and 4 in which the inclination angle a of the narrow groove 22 in the test tires 1 and 2 with respect to the perpendicular S to the perpendicular S was 0 degree. In the test tire 4, the value was 121. Here, the braking distance at an index of 100 was 40 m. Thus, the pneumatic tire to which the present invention is applied can obtain sufficient ice and snow performance even at the very beginning of wear.
発明の効果 以上説明したように、この発明によれば、摩耗の極く
初期、即ち被覆ゴム層の消失以前における氷雪性能をも
良好とすることができる。Effect of the Invention As described above, according to the present invention, the ice and snow performance at the very beginning of wear, that is, before the disappearance of the coating rubber layer can be improved.
第１図はこの発明の一実施例を示すトレッド近傍の子午
線断面図、第２図は試験に使用した比較タイヤのトレッ
ドの平面図、第３図は第２図のＩ−Ｉ矢視断面図、第４
図は試験に使用した供試タイヤ１のトレッドの平面図、
第５図は試験に使用した供試タイヤ２の第１図と同様の
断面図である。 ６……トレッド、11……外側ゴム層 12……内側ゴム層、16、17……溝 18……陸部、21……被覆ゴム層 22……細溝FIG. 1 is a meridian sectional view in the vicinity of a tread showing one embodiment of the present invention, FIG. 2 is a plan view of a tread of a comparative tire used for a test, and FIG. 3 is a sectional view taken along line II of FIG. , Fourth
The figure is a plan view of the tread of the test tire 1 used for the test,
FIG. 5 is a sectional view similar to FIG. 1 of the test tire 2 used in the test. 6 ... tread, 11 ... outer rubber layer 12 ... inner rubber layer, 16, 17 ... groove 18 ... land, 21 ... coating rubber layer 22 ... narrow groove
フロントページの続き (56)参考文献 特開 昭62−283001（ＪＰ，Ａ) 特開 昭63−90402（ＪＰ，Ａ) 特開 昭61−64503（ＪＰ，Ａ) 特開 昭62−39304（ＪＰ，Ａ) 実開 昭60−105502（ＪＰ，Ｕ) 実開 昭61−39604（ＪＰ，Ｕ) 実公 平１−9682（ＪＰ，Ｙ２) 特許2568502（ＪＰ，Ｂ２) 特許2568520（ＪＰ，Ｂ２)Continuation of the front page (56) References JP-A-62-283001 (JP, A) JP-A-63-90402 (JP, A) JP-A-61-64503 (JP, A) JP-A-62-39304 (JP, A) , A) Japanese Utility Model Application Showa 60-105502 (JP, U) Japanese Utility Model Application Showa 61-39604 (JP, U) Japanese Utility Model Application 1-9682 (JP, Y2) Patent 2568502 (JP, B2) Patent 2568520 (JP, B2)
Claims (2)
半径方向内方に位置する内側ゴム層の少なくとも２層の
ゴム層からなり、その表面に溝および陸部が形成された
トレッドを有する空気入りタイヤにおいて、前記内側ゴ
ム層をショアーＡ硬度が外側ゴム層のショアーＡ硬度よ
り高いゴムから構成するとともに、前記外側ゴム層を発
泡ゴムから構成し、かつ、前記外側ゴム層の表面を発泡
率が外側ゴム層の発泡率より小さいゴムからなる被覆ゴ
ム層により被覆するとともに、前記陸部表面に溝深さが
4.5mm以下の多数の細溝を形成したことを特徴とする空
気入りタイヤ。1. A tread comprising at least two rubber layers, an outer rubber layer located radially outward and an inner rubber layer located radially inward, and having grooves and land portions formed on the surface thereof. In the pneumatic tire, the inner rubber layer is made of rubber having a Shore A hardness higher than the Shore A hardness of the outer rubber layer, the outer rubber layer is made of foamed rubber, and the surface of the outer rubber layer is foamed. While the outer rubber layer is covered with a coating rubber layer made of a rubber smaller than the foaming rate of the outer rubber layer, and a groove depth is formed on the land portion surface.
A pneumatic tire having a large number of narrow grooves of 4.5 mm or less.
項１記載の空気入りタイヤ。2. The pneumatic tire according to claim 1, wherein the narrow groove has a groove depth of 1.0 mm or more.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP1007325A JP2754227B2 (en) | 1989-01-13 | 1989-01-13 | Pneumatic tire |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP1007325A JP2754227B2 (en) | 1989-01-13 | 1989-01-13 | Pneumatic tire |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH02189203A JPH02189203A (en) | 1990-07-25 |
| JP2754227B2 true JP2754227B2 (en) | 1998-05-20 |
Family
ID=11662814
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP1007325A Expired - Lifetime JP2754227B2 (en) | 1989-01-13 | 1989-01-13 | Pneumatic tire |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2754227B2 (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20140034200A1 (en) * | 2012-07-31 | 2014-02-06 | Bridgestone Americas Tire Operations, Llc | Tire with laminate |
Families Citing this family (18)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH0781315A (en) * | 1993-09-20 | 1995-03-28 | Sumitomo Rubber Ind Ltd | Pneumatic tire |
| JP3360921B2 (en) * | 1994-03-25 | 2003-01-07 | 株式会社ブリヂストン | Pneumatic tire |
| DE102004014006A1 (en) | 2004-03-23 | 2005-10-13 | Continental Ag | Vehicle tires |
| JP4632756B2 (en) * | 2004-11-16 | 2011-02-16 | 株式会社ブリヂストン | Pneumatic tire manufacturing method |
| DE102005042569A1 (en) * | 2005-09-08 | 2007-03-22 | Continental Aktiengesellschaft | Vehicle tires |
| JP4750524B2 (en) * | 2005-10-11 | 2011-08-17 | 株式会社ブリヂストン | Pneumatic tire |
| FR2918314B1 (en) | 2007-07-02 | 2009-08-21 | Michelin Soc Tech | PNEUMATIC COMPRISING A TREAD WITH RUBBER FOAM. |
| FR2918313B1 (en) | 2007-07-02 | 2009-08-21 | Michelin Soc Tech | PNEUMATIC COMPRISING A HIGH ADHESIVE BEARING BAND. |
| FR2962372B1 (en) | 2010-07-06 | 2014-05-02 | Michelin Soc Tech | BEARING BAND PROTECTION DEVICE |
| JP5715452B2 (en) * | 2011-03-11 | 2015-05-07 | 株式会社ブリヂストン | Pneumatic tire |
| US20140034199A1 (en) * | 2012-07-31 | 2014-02-06 | Bridgestone Americas Tire Operations, Llc | Tire with laminate |
| DE102017211128A1 (en) * | 2017-06-30 | 2019-01-03 | Continental Reifen Deutschland Gmbh | Vehicle tires |
| DE102017211129A1 (en) * | 2017-06-30 | 2019-01-03 | Continental Reifen Deutschland Gmbh | Vehicle tires |
| JP2021519724A (en) * | 2018-03-30 | 2021-08-12 | コンパニー ゼネラール デ エタブリッスマン ミシュラン | Tires including tread |
| US20210053397A1 (en) * | 2018-03-30 | 2021-02-25 | Compagnie Generale Des Etablissements Michelin | A tire comprising a tread |
| US11767417B2 (en) | 2018-03-30 | 2023-09-26 | Compagnie Generale Des Etablissements Michelin | Tire comprising a tread |
| DE102019204326A1 (en) * | 2019-03-28 | 2020-10-01 | Continental Reifen Deutschland Gmbh | Pneumatic vehicle tires |
| KR102280795B1 (en) * | 2020-01-21 | 2021-07-22 | 넥센타이어 주식회사 | Tire |
-
1989
- 1989-01-13 JP JP1007325A patent/JP2754227B2/en not_active Expired - Lifetime
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20140034200A1 (en) * | 2012-07-31 | 2014-02-06 | Bridgestone Americas Tire Operations, Llc | Tire with laminate |
Also Published As
| Publication number | Publication date |
|---|---|
| JPH02189203A (en) | 1990-07-25 |
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