JP5288781B2 - Pneumatic tire - Google Patents

Pneumatic tire Download PDF

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JP5288781B2
JP5288781B2 JP2007312266A JP2007312266A JP5288781B2 JP 5288781 B2 JP5288781 B2 JP 5288781B2 JP 2007312266 A JP2007312266 A JP 2007312266A JP 2007312266 A JP2007312266 A JP 2007312266A JP 5288781 B2 JP5288781 B2 JP 5288781B2
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tread
tire
sipe
land portion
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JP2009137315A (en
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秀敏 依田
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Bridgestone Corp
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Bridgestone Corp
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    • 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
    • B60C11/0311—Patterns comprising tread lugs arranged parallel or oblique to the axis of rotation
    • 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
    • B60C2200/00—Tyres specially adapted for particular applications
    • B60C2200/06—Tyres specially adapted for particular applications for heavy duty vehicles
    • B60C2200/065—Tyres specially adapted for particular applications for heavy duty vehicles for construction vehicles

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Tires In General (AREA)

Description

本発明は、トレッドにラグ溝を有する重荷重用タイヤに関し、主に鉱山などで鉱石や表土を運搬する車両に装着される空気入りタイヤに関するものである。   The present invention relates to a heavy duty tire having a lug groove in a tread, and more particularly to a pneumatic tire mounted on a vehicle that transports ore and topsoil in a mine or the like.

トレッドにラグ溝を有する従来の重荷重用タイヤにおいて、トレッドの耐摩耗性を向上させるために、トレッドゲージ（溝の位置におけるトレッド表面からベルト層までの間隔）の増加やネガティブ比（トレッドの溝が占める面積の割合）の減少等、トレッドの体積を増加させる方法が用いられてきた。しかし、ラグ溝が深いトレッドにおいては、ラグ溝に挟まれた陸部の踏み込み側に対して蹴り出し側の摩耗が早く進む偏摩耗、いわゆるヒールアンドトウ摩耗が発生していた。ここで、踏み込み側とは、タイヤ幅方向に延びる溝によって区画された陸部を有するタイヤを装着した車両が走行し、タイヤが回転する際、陸部内の最初に接地する部分を指し、蹴り出し側とは、当該陸部内の最後まで接地している部分を指す。
このヒールアンドトウ摩耗によって、トレッドの体積を増加させたことによるトレッドの耐摩耗効果は相殺されるため、ヒールアンドトウ摩耗の発生を抑制しトレッドの耐摩耗性を向上させることが求められていた。 In conventional heavy-duty tires with lug grooves on the tread, an increase in tread gauge (distance from the tread surface to the belt layer at the groove position) and negative ratio (the tread groove is increased) in order to improve the wear resistance of the tread. A method of increasing the volume of the tread has been used, such as a reduction in the ratio of the area occupied. However, in a tread having a deep lug groove, uneven wear, that is, so-called heel and toe wear, occurs in which wear on the kicking side quickly proceeds with respect to the stepping side of the land portion sandwiched between the lug grooves. Here, the stepping-on side refers to the part of the land portion that contacts the ground first when the vehicle equipped with the tire having the land portion partitioned by the groove extending in the tire width direction rotates, and kicks out. The side refers to a portion that is grounded to the end in the land portion.
Since the heel and toe wear offsets the wear resistance effect of the tread due to the increase in the tread volume, it has been required to suppress the occurrence of heel and toe wear and improve the tread wear resistance. .

トレッドにラグ溝を有する従来の重荷重用タイヤにおいて、ヒールアンドトウ摩耗の発生を抑制した例として、タイヤ赤道からトレッドの接地端までのタイヤ軸方向距離をＬとしたときに、少なくともタイヤ赤道からタイヤ軸方向外側への距離が０．４５Ｌ〜０．５５Ｌの領域内において、接地端に向けて幅が増加すると共に、踏み込み側の溝壁と蹴り出し側の溝壁とがタイヤ軸方向に対して互いに反対方向に傾斜し、踏み込み側の溝壁、および蹴り出し側の溝壁のタイヤ周方向に対する角度が７０〜８５°の範囲内に設定されているラグ溝を有するタイヤが提案されている（例えば、特許文献１）。   As an example of suppressing heel and toe wear in a conventional heavy duty tire having a lug groove on a tread, when the distance in the tire axial direction from the tire equator to the ground contact end of the tread is L, at least from the tire equator to the tire In the region where the distance to the outside in the axial direction is 0.45L to 0.55L, the width increases toward the ground contact end, and the groove wall on the stepping side and the groove wall on the kicking side are in the tire axial direction. There has been proposed a tire having lug grooves that are inclined in opposite directions and in which the angle of the groove wall on the stepping side and the groove wall on the kicking side with respect to the tire circumferential direction is set within a range of 70 to 85 ° ( For example, Patent Document 1).

特開２００６−２１３１７７号公報JP 2006-213177 A

しかし、上述したタイヤでも、ヒールアンドトウ摩耗の発生が十分に抑制されているとは言えず、更なる抑制に対する要求があった。   However, even in the above-described tire, it cannot be said that the occurrence of heel and toe wear is sufficiently suppressed, and there is a demand for further suppression.

そこで、本発明の目的は、上述した問題点を解消して、ヒールアンドトウ摩耗の発生を抑制して、トレッドの耐摩耗性をさらに向上したタイヤを提供することにある。   Accordingly, an object of the present invention is to provide a tire that solves the above-described problems, suppresses the occurrence of heel and toe wear, and further improves the wear resistance of the tread.

本発明の要旨は、以下のとおりである。
（１）タイヤのトレッドに、各トレッド端からタイヤ赤道に向かって延びる複数本のラグ溝と、前記ラグ溝によって区画された複数の陸部とを有するタイヤにおいて、
各陸部のタイヤ周方向端部のいずれか一方の側に、一端がラグ溝に連通し、他端が陸部内で終了する複数本のサイプを、陸部相互間で同じ側の端部に設けてなり、
前記サイプは、トレッド幅の２％以上６％以下の間隔をもって配置され、
前記陸部の、サイプが配置された部分がタイヤを車両に装着した際の踏み込み側であることを特徴とする空気入りタイヤ。 The gist of the present invention is as follows.
(1) In a tire having a plurality of lug grooves extending from each tread end toward the tire equator and a plurality of land portions partitioned by the lug grooves on the tread of the tire,
A plurality of sipes having one end communicating with the lug groove and the other end ending in the land portion on either side of the tire circumferential end of each land portion are arranged on the same side between the land portions. Established
The sipes are arranged at intervals of 2% to 6% of the tread width ,
The pneumatic tire according to claim 1, wherein a portion of the land portion where the sipes are disposed is a stepping side when the tire is mounted on the vehicle .

（２）トレッドを、タイヤ赤道を含み、トレッド幅の２０％以上４０％以下の幅にまたがるトレッド中央領域と、該トレッド中央領域の両側のトレッド側方領域とに区画すると、
前記ラグ溝は、両トレッド側方領域に配置され、かつ
前記トレッド中央領域の両側の各トレッド側方領域に配置されたラグ溝が、互いに交差する向きに延び、
さらに溝深さが、タイヤ断面高さの６％以上１５％以下である、
ことを特徴とする上記（１）に記載の空気入りタイヤ。 ( 2 ) When the tread is divided into a tread central region that includes the tire equator and spans a width of 20% to 40% of the tread width, and tread side regions on both sides of the tread central region,
The lug grooves are arranged in both tread side areas, and the lug grooves arranged in the tread side areas on both sides of the tread central area extend in a direction intersecting each other,
Further, the groove depth is 6% or more and 15% or less of the tire cross-section height.
The pneumatic tire according to (1 ) above, wherein

（３）前記サイプの幅が、１．５ｍｍ以上３．５ｍｍ以下であることを特徴とする上記（１）または（２）に記載の空気入りタイヤ。 ( 3 ) The pneumatic tire according to (1) or (2) above, wherein the width of the sipe is 1.5 mm or more and 3.5 mm or less.

（４）前記サイプの長さは、前記サイプが配置された陸部の周方向の長さの１０％以上３０％以下であることを特徴とする上記（１）〜（３）のいずれかに記載の空気入りタイヤ。 ( 4 ) The length of the sipe is not less than 10% and not more than 30% of the circumferential length of the land portion where the sipe is arranged. Any one of the above (1) to ( 3 ) The described pneumatic tire.

（５）前記サイプが連通するラグ溝に対する前記サイプの角度は、４５°以上１３５°以下であることを特徴とする上記（１）〜（４）のいずれかに記載の空気入りタイヤ。 ( 5 ) The pneumatic tire according to any one of (1) to ( 4 ), wherein an angle of the sipe with respect to a lug groove with which the sipe communicates is 45 ° or more and 135 ° or less.

（６）トレッドのネガティブ比が３０％以下であることを特徴とする上記（１）〜（５）のいずれかに記載の空気入りタイヤ。 ( 6 ) The pneumatic tire according to any one of (1) to ( 5 ) above, wherein the tread negative ratio is 30% or less.

本発明によれば、タイヤのトレッドのラグ溝で挟まれた陸部に、一端が一方のラグ溝に連通し、他端が陸部内で終了する複数本のサイプをトレッド幅の２％以上６％以下の間隔をもって配置することにより、このタイヤを、陸部のサイプが配置された部分が踏み込み側となるように車両に装着した際に、ヒールアンドトゥ摩耗の発生を抑制することが可能となるから、トレッドの耐摩耗性をさらに向上した空気入りタイヤを提供することができる。 According to the present invention, a plurality of sipes having one end communicating with one lug groove and the other end ending in the land portion in the land portion sandwiched between the lug grooves of the tread of the tire are 2% or more of the tread width. By arranging the tires with an interval of% or less, it is possible to suppress the occurrence of heel and toe wear when the tire is mounted on the vehicle so that the portion where the land sipe is located is on the stepping side. A pneumatic tire with further improved tread wear resistance can be provided.

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

図１は、本発明の空気入りタイヤの実施形態を示すトレッドパターンの展開図である。
図示のトレッドパターンは、タイヤのトレッド１に、一方のトレッド端Ｅからタイヤ赤道ＣＬに向かって延びるラグ溝２ａと、他方のトレッド端Ｅからタイヤ赤道ＣＬに向かって延びるラグ溝２ｂと、ラグ溝２ａおよび２ｂをつなぐ傾斜溝３とを有し、ラグ溝２ａ、２ｂおよび傾斜溝３によってトレッド１を複数の陸部４に区画している。各陸部４には、一端がラグ溝２ａ、２ｂに連通し、他端が陸部４内で終了する複数本のサイプ５が、各陸部４のタイヤ周方向の同一側に配置されており、陸部４のサイプ５が配置された部分が踏み込み側となるようにタイヤを車両に装着した際、以下に示す作用・効果が期待できる。なお、図中に示した矢印はタイヤ回転方向を表す。 FIG. 1 is a development view of a tread pattern showing an embodiment of a pneumatic tire of the present invention.
The illustrated tread pattern includes a lug groove 2a extending from one tread end E toward the tire equator CL, a lug groove 2b extending from the other tread end E toward the tire equator CL, and a lug groove. The tread 1 is divided into a plurality of land portions 4 by the lug grooves 2 a, 2 b and the inclined grooves 3. In each land portion 4, a plurality of sipes 5 having one end communicating with the lug grooves 2 a and 2 b and the other end ending in the land portion 4 are arranged on the same side in the tire circumferential direction of each land portion 4. Thus, when the tire is mounted on the vehicle so that the portion where the sipe 5 of the land portion 4 is disposed is on the stepping side, the following actions and effects can be expected. In addition, the arrow shown in the figure represents the tire rotation direction.

まず、タイヤを車両に装着するに当たり、前記陸部４のサイプ５を設けた側が踏み込み側に配置される装着姿勢とする。かように装着されたタイヤが回転する際、陸部４の蹴り出し側においては、蹴り出し時にブレーキング方向のすべりが発生している。耐摩耗性の向上を所期して陸部のタイヤ周方向長さに比しラグ溝の深さを大きくした場合、ブレーキング方向のすべりがさらに増大して、ヒールアンドトゥ摩耗の程度が大きくなることが分かっている。
そこで、本発明者は、蹴り出し時に陸部４の蹴り出し側に発生するブレーキング方向の動きを低減することを検討したところ、陸部４の蹴り出し側の反対側にある踏み込み側の剛性を高くすると、蹴り出し側のブレーキング方向のすべりが大きくなり、この剛性を低くすると、蹴り出し側のブレーキング方向のすべりが小さくなることを知見した。この理由を図１のラグ溝２ａを挟む一方の陸部４の踏み込み側と他方の陸部４の蹴り出し側に注目して説明する。タイヤの回転に伴い、踏み込み側から蹴り出し側に荷重が移動するが、路面から離れていく蹴り出し側は、踏み込み側からの荷重移動の影響で変形し、蹴りだす際にブレーキング方向のすべりを発生させている。そこで、踏み込み側の陸部４の剛性を下げることで、原因となる変形を減少させることができる。
それゆえ、サイプ５を、タイヤのトレッド１のラグ溝２ａ、２ｂで挟まれた陸部４に、一端が一方のラグ溝に連通し、他端が陸部内で終了するように配置することにより、各陸部のタイヤ周方向端部域の一方の剛性を低くする。そして、このタイヤを、陸部４のサイプ５が配置された部分が踏み込み側となるように車両に装着した際に、サイプを設けた部分の剛性が低いため、前記ブレーキング方向のすべりは小さくなり、その結果、ヒールアンドトゥ摩耗の発生が抑制され、トレッドの耐摩耗性を向上することができる。 First, when the tire is mounted on the vehicle, the mounting posture is such that the side of the land portion 4 where the sipe 5 is provided is disposed on the stepping side. When the tire thus mounted rotates, on the kicking side of the land portion 4, slipping in the braking direction occurs during kicking. If the depth of the lug groove is increased compared to the land circumferential length of the tire for the purpose of improving wear resistance, the slipping in the braking direction may further increase and the degree of heel and toe wear may increase. I know.
Therefore, the present inventor examined reducing the movement in the braking direction that occurs on the kicking side of the land portion 4 during kicking, and found that the rigidity on the stepping side on the opposite side of the kicking side of the land portion 4 was reduced. It has been found that when the height is increased, the slipping in the braking direction on the kicking side increases, and when the rigidity is lowered, the slipping in the braking direction on the kicking side decreases. The reason for this will be described by paying attention to the stepping side of one land portion 4 and the kicking side of the other land portion 4 sandwiching the lug groove 2a of FIG. As the tire rotates, the load moves from the stepping side to the kicking side, but the kicking side that moves away from the road surface is deformed by the load movement from the stepping side and slips in the braking direction when kicking out. Is generated. Therefore, the cause deformation can be reduced by lowering the rigidity of the land portion 4 on the stepping side.
Therefore, by arranging the sipe 5 in the land portion 4 sandwiched between the lug grooves 2a and 2b of the tread 1 of the tire so that one end communicates with one lug groove and the other end ends in the land portion. The rigidity of one of the end portions in the tire circumferential direction of each land portion is lowered. And when this tire is mounted on the vehicle so that the portion where the sipe 5 of the land portion 4 is located is on the stepping side, the rigidity of the portion provided with the sipe is low, so that the slip in the braking direction is small. As a result, the occurrence of heel and toe wear is suppressed, and the wear resistance of the tread can be improved.

ここで、図１に示すように、トレッド１を、タイヤ赤道ＣＬを含むトレッド中央領域１Ｃと、このトレッド中央領域１Ｃの両側のトレッド側方領域１Ｓａ、１Ｓｂとに区画すると、ラグ溝２ａ、２ｂはトレッド側方領域１Ｓａ、１Ｓｂにそれぞれ設けることが好ましい。ここでいうトレッド中央領域１Ｃの幅ＣＷはトレッド幅ＴＷの２０％以上４０％以下である。
まず、トレッド中央領域１Ｃの幅ＣＷがトレッド幅ＴＷの２０％未満になると、すなわち、ラグ溝２ａ、２ｂがタイヤ赤道ＣＬ付近まで延在すると、陸部４の剛性が低下するため、タイヤ赤道Ｃの陸部の摩耗が早く進行し、摩耗末期に、タイヤ赤道Ｃの陸部以外のトレッドゲージを残した状態で、タイヤ赤道Ｃの陸部でベルトが露出し、タイヤを取り外さなければいけないというおそれが生ずる。
一方、トレッド中央領域１Ｃの幅ＣＷがトレッド幅ＴＷの４０％超になると、すなわち、ラグ溝２ａ、２ｂが短い場合、ラグ溝のエッジ部の領域が幅方向に短くなりすぎ、タイヤが滑りやすくなり、駆動力や制動力がかかった際のスリップ量が増加し、摩耗が早く進行するおそれがある。
また、サイプ５を各トレッド側方領域１Ｓａ、１Ｓｂの外側のショルダー部にまで配置すると、ショルダー部で石を踏んだ際に陸部のもげの起点となるという問題が生ずる。 Here, as shown in FIG. 1, when the tread 1 is divided into a tread central region 1C including the tire equator CL and tread side regions 1Sa, 1Sb on both sides of the tread central region 1C, lug grooves 2a, 2b Are preferably provided in the tread side regions 1Sa and 1Sb, respectively. The width CW of the tread central region 1C here is 20% or more and 40% or less of the tread width TW.
First, when the width CW of the tread central region 1C becomes less than 20% of the tread width TW, that is, when the lug grooves 2a and 2b extend to the vicinity of the tire equator CL, the rigidity of the land portion 4 decreases. There is a risk that the wear of the land portion of the tire will progress quickly, and at the end of the wear, with the tread gauge other than the land portion of the tire equator C left, the belt will be exposed at the land portion of the tire equator C and the tire must be removed Will occur.
On the other hand, when the width CW of the tread central region 1C exceeds 40% of the tread width TW, that is, when the lug grooves 2a and 2b are short, the edge region of the lug groove is too short in the width direction, and the tire is slippery. Therefore, the slip amount when the driving force or the braking force is applied increases, and there is a possibility that the wear progresses quickly.
Further, when the sipe 5 is disposed up to the shoulder portions outside the respective tread side regions 1Sa and 1Sb, there arises a problem that when the stone is stepped on the shoulder portions, it becomes a starting point for baldness of the land portion.

また、ラグ溝２ａと２ｂとは、図１に示すようにタイヤ赤道ＣＬに集束する向きに延びる配置とすることが好適である。
なぜなら、ラグ溝を略平行に揃えて配置すると、タイヤの回転によりトレッド踏面内に出入りする陸部とラグ溝の変化による接地面積変化が大きくなり、その影響で振動が発生するおそれがあるためである。 Further, the lug grooves 2a and 2b are preferably arranged so as to extend in a direction converging on the tire equator CL as shown in FIG.
This is because if the lug grooves are arranged substantially parallel to each other, the ground contact area changes due to changes in the land and lug grooves that enter and exit the tread surface due to the rotation of the tire, and there is a possibility that vibrations may occur due to the influence. is there.

また、ラグ溝２ａ、２ｂの深さが、タイヤ断面高さの６％以上１５％以下であることが好適である。
なぜなら、ラグ溝２ａ、２ｂの深さが、タイヤ断面高さの６％未満の場合、ラグ溝２ａ、２ｂが浅すぎて、悪路走行でのラグ溝内への泥詰まりによるタイヤの駆動力や制動力が低下するおそれや、フロント装着時、石を踏んだ際にタイヤがバーストするおそれがあるからである。
一方、ラグ溝２ａ、２ｂの深さが、タイヤ断面高さの１５％超の場合、ラグ溝２ａ、２ｂが深すぎて、タイヤに対し、トレッド体積が多くなりすぎ、発熱に起因したセパレーション（ヒートセパレート）などの故障を発生させるおそれがある。 Moreover, it is preferable that the depth of the lug grooves 2a and 2b is 6% or more and 15% or less of the tire cross-sectional height.
This is because when the depth of the lug grooves 2a and 2b is less than 6% of the tire cross-sectional height, the lug grooves 2a and 2b are too shallow, and the driving force of the tire due to mud clogging in the lug grooves on rough roads This is because there is a risk that the braking force may be reduced or the tire may burst when a stone is stepped on when wearing the front.
On the other hand, when the depth of the lug grooves 2a and 2b is more than 15% of the tire cross-sectional height, the lug grooves 2a and 2b are too deep, and the tread volume is too large for the tire, resulting in separation caused by heat generation ( There is a risk of causing a failure such as heat separation.

サイプ５の幅ＳＷが、１．５ｍｍ以上３．５ｍｍ以下であることが好適である。
なぜなら、サイプ５の幅ＳＷが１．５ｍｍ未満の場合、陸部４の踏み込み側の剛性低減効果が小さく、一方３．５ｍｍ超の場合、陸部の体積が減少し、踏み込み側の摩耗が進行し易くなるためである。 It is preferable that the width SW of the sipe 5 is 1.5 mm or more and 3.5 mm or less.
This is because if the width SW of the sipe 5 is less than 1.5 mm, the effect of reducing the rigidity of the land portion 4 on the stepping side is small, while if it exceeds 3.5 mm, the volume of the land portion decreases and wear on the stepping side proceeds. It is because it becomes easy to do.

サイプ５の長さＳＬは、この１本のサイプ５が配置された陸部４の周方向の長さＬＬの１０％以上３０％以下であることが好適である。
なぜなら、サイプ５の長さＳＬが陸部４の周方向の長さＬＬの１０％未満の場合、陸部４の踏み込み側の剛性低減効果が小さく、一方３０％超の場合、陸部４全体としての剛性が低下し、耐摩耗性が低下するためである。 The length SL of the sipe 5 is preferably 10% or more and 30% or less of the circumferential length LL of the land portion 4 where the single sipe 5 is arranged.
This is because when the length SL of the sipe 5 is less than 10% of the circumferential length LL of the land portion 4, the effect of reducing the rigidity on the stepping side of the land portion 4 is small, whereas when it exceeds 30%, the entire land portion 4 This is because the rigidity of the material decreases and the wear resistance decreases.

サイプ５が連通するラグ溝２ａ、２ｂに対するサイプ５の角度ＳＡは、４５°以上１３５°以下であることが好適である。
なぜなら、角度ＳＡが４５°未満あるいは１３５°超の場合、すなわち、サイプ５が陸部４を４５°未満の鋭角に切断する場合、陸部４のゴムのもげが発生するおそれがあるためである。 The angle SA of the sipe 5 with respect to the lug grooves 2a and 2b with which the sipe 5 communicates is preferably 45 ° or more and 135 ° or less.
This is because when the angle SA is less than 45 ° or more than 135 °, that is, when the sipe 5 cuts the land portion 4 into an acute angle of less than 45 °, there is a possibility that the rubber baldness of the land portion 4 may occur. .

サイプ５は、トレッド幅ＴＷの２％以上６％以下の間隔ＳＩをもって配置することが肝要である。
サイプ５の間隔ＳＩがトレッド幅ＴＷの２％未満の場合、サイプ５を設けた箇所の陸部４の動きが大きくなり、その結果サイプ５の底部にクラックが発生し、それがもとで陸部端部のもげが発生するおそれがある。一方６％超の場合、陸部の剛性低減効果が小さくなるおそれがある。 It is important to arrange the sipe 5 with an interval SI of 2% to 6% of the tread width TW .
When the interval SI between the sipe 5 is less than 2% of the tread width TW, the movement of the land portion 4 where the sipe 5 is provided increases, and as a result, a crack is generated at the bottom of the sipe 5, and the land There is a risk of baldness at the end of the part. On the other hand, if it exceeds 6%, the effect of reducing the rigidity of the land may be reduced.

トレッド１のネガティブ比が３０％以下であることが好適である。
なぜなら、３０％超の場合、溝の占める割合が大きくなり、接地面積が減少し、陸部の剛性が低下するおそれがあるためである。 The negative ratio of tread 1 is preferably 30% or less.
This is because if it exceeds 30%, the ratio of the groove increases, the contact area decreases, and the rigidity of the land portion may decrease.

トレッド中央領域ＣＷの陸部４は傾斜溝３によって区画され、傾斜溝３の溝幅ＧＨはピッチ長ＰＬの３％以上８％以下であることが好適である。
なぜなら、溝幅ＧＨがピッチ長ＰＬの３％未満の場合、トレッド踏面内で、傾斜溝３が閉じることにより、トレッド中央領域ＣＷとそれ以外の領域の径差吸収が不充分となり、径差による摩耗進行のおそれがあるためである。
一方、８％超の場合、トレッド中央領域ＣＷの陸部４の剛性が低下し、トレッド中央領域ＣＷの摩耗が進行するためである。
また、この傾斜溝３を設けずにトレッド中央領域ＣＷの陸部４を周方向に連続させてもよい。 The land portion 4 of the tread central region CW is partitioned by the inclined groove 3, and the groove width GH of the inclined groove 3 is preferably 3% or more and 8% or less of the pitch length PL.
This is because when the groove width GH is less than 3% of the pitch length PL, the inclined groove 3 is closed in the tread surface, so that the difference in diameter difference between the tread central area CW and the other areas becomes insufficient, resulting in the difference in diameter. This is because wear may occur.
On the other hand, if it exceeds 8%, the rigidity of the land portion 4 in the tread central region CW is lowered, and wear of the tread central region CW proceeds.
Moreover, you may make the land part 4 of the tread center area | region CW continue in the circumferential direction, without providing this inclination groove | channel 3. As shown in FIG.

サイプ５を設けた陸部４の壁面、すなわちラグ溝２ａおよび２ｂの溝壁の、タイヤ赤道ＣＬに対する角度Ａｎ１およびＡｎ２が同一であることが好適である。
なぜなら、角度Ａｎ１およびＡｎ２を変えると、摩耗量に差が出て、タイヤ赤道Ｃを挟んで一方と他方で不均一な摩耗が生じるおそれがあるためである。 It is preferable that the angles An1 and An2 of the wall surface of the land portion 4 provided with the sipe 5, that is, the groove walls of the lug grooves 2a and 2b, with respect to the tire equator CL are the same.
This is because, if the angles An1 and An2 are changed, there is a possibility that a difference in the amount of wear occurs and uneven wear occurs on one side and the other side across the tire equator C.

図１に示す発明例タイヤおよび比較例タイヤを試作し、各試作タイヤを鉱山で走行中の積載量２４０ｔのダンプカーに装着し、ラグ溝の深さの略１／２までの耐摩耗（走行時間／（ＯＴＤ−ＲＴＤ：Overall Tread Depth-Residual Tread Depth））を評価したので、以下に説明する。
発明例タイヤおよび比較例タイヤはいずれも、タイヤサイズ４６／９０Ｒ５７、タイヤ外径３５７５ｍｍ、トレッド幅１０４５ｍｍ、ラグ溝深さ（ＯＴＤ）９７ｍｍ、ネガティブ比１８％を有する。
発明例タイヤ１〜５は、表１に示すようにサイプの幅（ＳＷ）、長さ（ＳＬ）、角度（ＳＡ）、間隔（ＳＩ）、配置範囲および、ラグ溝の向きと深さを変化させたものであり、比較例タイヤはサイプを設けていない点以外は発明例タイヤと同様の構造である。なお、表１において、サイプの長さ（ＳＬ）とは、サイプが配置された陸部の周方向の長さに対する割合を％で示している。サイプの角度（ＳＡ）とは、サイプが連通するラグ溝に対する角度を示している。サイプの間隔（ＳＩ）とは、トレッド幅に対する割合を％で示している。サイプの配置範囲に関して、トレッド中央領域とは、タイヤ赤道を含み、トレッド幅の２０％以上４０％以下の幅にまたがるトレッド部分であり、トレッド側方領域とは、このトレッド中央領域の両側のトレッド部分を示す。ラグ溝の向きに関して、交差とは、トレッド側方領域に配置された各ラグ溝が、タイヤ赤道に対して互いに交差する向きに延びていることを示し、平行とは、トレッド側方領域に配置された各ラグ溝が、平行に延びていることを示す。ラグ溝の深さとは、タイヤ断面高さに対する割合を％で示す。 Inventive tires and comparative tires shown in FIG. 1 were prototyped, and each prototype tire was mounted on a dump truck having a loading capacity of 240 t while traveling in a mine, and the wear resistance (running time up to approximately ½ of the depth of the lug groove) / (OTD-RTD: Overall Tread Depth-Residual Tread Depth)) was evaluated, and will be described below.
Each of the inventive tire and the comparative tire has a tire size of 46 / 90R57, a tire outer diameter of 3575 mm, a tread width of 1045 mm, a lug groove depth (OTD) of 97 mm, and a negative ratio of 18%.
Inventive tires 1 to 5 change sipe width (SW), length (SL), angle (SA), spacing (SI), arrangement range, and lug groove direction and depth as shown in Table 1. The comparative example tire has the same structure as the invention example tire except that no sipes are provided. In Table 1, the length of the sipe (SL) indicates a ratio with respect to the length in the circumferential direction of the land portion where the sipe is arranged in%. The sipe angle (SA) indicates an angle with respect to the lug groove with which the sipe communicates. The sipe interval (SI) indicates the ratio to the tread width in%. Regarding the sipe arrangement range, the tread central region is a tread portion that includes the tire equator and spans 20% to 40% of the tread width, and the tread side region is a tread on both sides of the tread central region. Indicates the part. Concerning the direction of the lug groove, crossing means that each lug groove arranged in the tread side region extends in a direction crossing each other with respect to the tire equator, and parallel means arranging in the tread side region It shows that each made lug groove extends in parallel. The depth of the lug groove indicates a ratio with respect to the tire cross-section height in%.

Figure 0005288781
Figure 0005288781

表１に示すヒールアンドトゥ摩耗は、トレッド踏面に定規をあて、蹴り出し部の落ち高を測定し、ヒールアンドトゥ摩耗なしを「０」とし、現行品の落ち高（ヒールアンドトゥ摩耗量）を「大」とし、その間の落ち高を「中」として示す。
また、耐摩耗性は比較例タイヤを１００としたときの指数で表し数値が大きいほど耐摩耗性が高いことを示す。 The heel and toe wear shown in Table 1 applies a ruler to the tread tread, measures the drop height of the kicked-out part, sets "0" to no heel and toe wear, and sets the drop height (heel and toe wear amount) of the current product to "large" The fall height during that time is shown as “medium”.
The wear resistance is expressed as an index when the comparative tire is set to 100, and the larger the value, the higher the wear resistance.

表１の結果より、比較例タイヤと比較して、陸部の踏み込み側にサイプを設けた発明例タイヤの方が、ヒールアンドトゥ摩耗の発生が抑制され、耐摩耗性が向上していることが分かった。   From the results in Table 1, it can be seen that the invention example tires provided with sipes on the stepping side of the land portion have reduced heel and toe wear and improved wear resistance compared to the comparative example tires. It was.

以上により、タイヤのトレッドの陸部にサイプを配置することにより、陸部のサイプが配置された部分が踏み込み側となるように車両に装着した際に、ヒールアンドトゥ摩耗の発生が抑制され、耐摩耗性をさらに向上した空気入りタイヤを提供することができる。   As described above, by arranging sipes in the land portion of the tread of the tire, the occurrence of heel and toe wear is suppressed and the wear resistance is reduced when the tire is mounted on the vehicle so that the portion where the sipes of the land portion are located on the stepping side. A pneumatic tire with further improved performance can be provided.

本発明の空気入りタイヤの実施形態を示すトレッドパターンの展開図である。It is a development view of a tread pattern showing an embodiment of a pneumatic tire of the present invention.

符号の説明Explanation of symbols

１ トレッド
１Ｃ トレッド中央領域
１Ｓａ、１Ｓｂ トレッド側方領域
２ａ、２ｂ ラグ溝
３ 傾斜溝
４ 陸部
５ サイプ
ＣＬ タイヤ赤道
Ｅ トレッド端 1 tread 1C tread central area 1Sa, 1Sb tread side area 2a, 2b lug groove 3 inclined groove 4 land 5 sipe CL tire equator E tread edge

Claims (6)

タイヤのトレッドに、各トレッド端からタイヤ赤道に向かって延びる複数本のラグ溝と、前記ラグ溝によって区画された複数の陸部とを有するタイヤにおいて、
各陸部のタイヤ周方向端部のいずれか一方の側に、一端がラグ溝に連通し、他端が陸部内で終了する複数本のサイプを、陸部相互間で同じ側の端部に設けてなり、
前記サイプは、トレッド幅の２％以上６％以下の間隔をもって配置され、
前記陸部の、サイプが配置された部分がタイヤを車両に装着した際の踏み込み側であることを特徴とする空気入りタイヤ。 In a tire having a plurality of lug grooves extending from the respective tread ends toward the tire equator and a plurality of land portions partitioned by the lug grooves on the tread of the tire,
A plurality of sipes having one end communicating with the lug groove and the other end ending in the land portion on either side of the tire circumferential end of each land portion are arranged on the same side between the land portions. Established
The sipes are arranged at intervals of 2% to 6% of the tread width ,
The pneumatic tire according to claim 1, wherein a portion of the land portion where the sipes are disposed is a stepping side when the tire is mounted on the vehicle . トレッドを、タイヤ赤道を含み、トレッド幅の２０％以上４０％以下の幅にまたがるトレッド中央領域と、該トレッド中央領域の両側のトレッド側方領域とに区画すると、
前記ラグ溝は、両トレッド側方領域に配置され、かつ
前記トレッド中央領域の両側の各トレッド側方領域に配置されたラグ溝が、互いに交差する向きに延び、
さらに溝深さが、タイヤ断面高さの６％以上１５％以下である、
ことを特徴とする請求項１に記載の空気入りタイヤ。 When the tread is partitioned into a tread central region that includes the tire equator and spans a width of 20% to 40% of the tread width, and tread side regions on both sides of the tread central region,
The lug grooves are arranged in both tread lateral regions, and
The lug grooves arranged in the respective tread side regions on both sides of the tread central region extend in directions intersecting each other,
Further, the groove depth is 6% or more and 15% or less of the tire cross-section height.
The pneumatic tire according to claim 1. 前記サイプの幅が、１．５ｍｍ以上３．５ｍｍ以下であることを特徴とする請求項１または２に記載の空気入りタイヤ。 The pneumatic tire according to claim 1 or 2, wherein a width of the sipe is 1.5 mm or more and 3.5 mm or less . 前記サイプの長さは、前記サイプが配置された陸部の周方向の長さの１０％以上３０％以下であることを特徴とする請求項１〜３のいずれか１項に記載の空気入りタイヤ。 The length of the said sipe is 10% or more and 30% or less of the circumferential length of the land part where the said sipe is arrange | positioned , The pneumatic of any one of Claims 1-3 characterized by the above-mentioned. tire. 前記サイプが連通するラグ溝に対する前記サイプの角度は、４５°以上１３５°以下であることを特徴とする請求項１〜４のいずれか１項に記載の空気入りタイヤ。 The pneumatic tire according to any one of claims 1 to 4, wherein an angle of the sipe with respect to a lug groove with which the sipe communicates is 45 ° or more and 135 ° or less . トレッドのネガティブ比が３０％以下であることを特徴とする請求項１〜５のいずれか１項に記載の空気入りタイヤ。 The pneumatic tire according to any one of claims 1 to 5, wherein a negative ratio of the tread is 30% or less .
JP2007312266A 2007-12-03 2007-12-03 Pneumatic tire Expired - Fee Related JP5288781B2 (en)

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