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JPH071918A - Heavy duty radial tire - Google Patents

Heavy duty radial tire

Info

Publication number
JPH071918A
JPH071918A JP5143168A JP14316893A JPH071918A JP H071918 A JPH071918 A JP H071918A JP 5143168 A JP5143168 A JP 5143168A JP 14316893 A JP14316893 A JP 14316893A JP H071918 A JPH071918 A JP H071918A
Authority
JP
Japan
Prior art keywords
tire
sipe
closed
bent
closed end
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.)
Withdrawn
Application number
JP5143168A
Other languages
Japanese (ja)
Inventor
Hiroshi Nakamura
博司 中村
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
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Toyo Tire and Rubber Co Ltd filed Critical Toyo Tire and Rubber Co Ltd
Priority to JP5143168A priority Critical patent/JPH071918A/en
Publication of JPH071918A publication Critical patent/JPH071918A/en
Withdrawn legal-status Critical Current

Links

Classifications

    • 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
    • B60C11/1218Three-dimensional shape with regard to depth and extending direction
    • 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
    • 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
    • B60C11/1236Tread patterns characterised by the use of narrow slits or incisions, e.g. sipes with special arrangements in the tread pattern
    • B60C2011/1254Tread patterns characterised by the use of narrow slits or incisions, e.g. sipes with special arrangements in the tread pattern with closed sipe, i.e. not extending to a groove

Landscapes

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

Abstract

PURPOSE:To provide a heavy duty radial tire where the stress concentration due to the vertical load during the traveling is suppressed by providing a number of sipings with one end open and the other end closed with keeping the space parallel to the direction of the tire rotating shaft, and providing roundness to the closed ends of the sipings at a large bending angle. CONSTITUTION:Small grooves 6 provided at the wheel print end 2 of the shoulder and in the tire circumferential direction are provided on both sides of a shoulder rib 5 of a tire tread part 1. A siping 7 of H in length is cut in the shoulder rib 5, one end is opened in the groove wall of the small grooves 6, and the other end is closed in a dead-end manner. The closed end 8 of the siping 7 is bent with smooth roundness at the bending angle exceeding 90 deg. and the siping 7 is passed from the open end 9 to the groove wall of the small grooves through a linear part 10 and a bent part 11 and terminated at the closed end 8. Even when the load is applied to the tire tread part during the traveling, and the transverse force caused by the slip of the tire surface and the deflection due to the vertical load of the rubber may be applied to the siping 7 as the resultant, the resultant may be applied to the whole bent part 11, causing no stress concentration.

Description

【発明の詳細な説明】Detailed Description of the Invention

【0001】[0001]

【産業上の利用分野】この発明は、重荷重用ラジアルタ
イヤにおいて、特にそのタイヤ踏面部に形成されたサイ
プの耐クラック寿命の改良に関する。
BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a radial tire for heavy loads, and more particularly to improvement of crack resistance life of sipes formed on the tread surface of the tire.

【0002】[0002]

【従来の技術】従来、タイヤ踏面部において、タイヤ周
方向に形成された主溝、副溝、細溝などの縦溝の溝壁、
或いはバットレス部からショルダー部の領域内に、一端
が開口し、他端が行き止まり状態で閉止したサイプが、
タイヤ回転軸方向にほぼ平行にかつタイヤ周方向に間隔
を置いて多数設置されているタイヤがある。
2. Description of the Related Art Conventionally, on a tire tread, a groove wall of vertical grooves such as a main groove, a sub groove, and a narrow groove formed in the tire circumferential direction,
Or, from the buttress portion to the area of the shoulder portion, a sipe that has one end opened and the other end closed in a dead end state,
There are many tires that are installed substantially parallel to the tire rotation axis direction and at intervals in the tire circumferential direction.

【0003】[0003]

【発明が解決しようとする課題】しかし従来のこの種の
タイヤは、走行中、タイヤ踏面部の摩耗寿命が尽きるま
での間に、当該サイプの行き止まりの閉止端からクラッ
クが発生する問題があった。そしてこれが成長すると、
そのサイプを含むその周辺部が一部欠けるといういわゆ
るサイプティアーが発生していた。
However, the conventional tire of this type has a problem that a crack is generated from the closed end of the dead end of the sipe until the wear life of the tire tread portion is exhausted during running. . And when this grows,
There was a so-called sipe tear that a part of the surrounding area including the sipe was missing.

【0004】従来、この種のサイプクラック及びサイプ
ティアーに対しては、格別有効な対策がとられてはおら
ず、寿命、耐久性の点で好ましくなかった。
Conventionally, no particularly effective countermeasure has been taken against this type of sipe crack and sipe tear, and it is not preferable in terms of life and durability.

【0005】この発明の目的は、走行中、サイプクラッ
ク及びサイプティアーの発生を有効に防止し、耐クラッ
ク寿命の向上を図ることができる重荷重用ラジアルタイ
ヤを提供する点にある。
An object of the present invention is to provide a heavy-duty radial tire capable of effectively preventing the occurrence of sipe cracks and sipe tears while traveling and improving the crack resistance life.

【0006】[0006]

【課題を解決するための手段】上記のサイプクラックお
よびサイプティアーが生じる原因を究明するため、サイ
プクラックおよびチッピングが生じたタイヤを鋭意観察
した。それによれば、クラックの発生方向は、タイヤ表
面のアブレージョンパターンから、タイヤ表面の応力
(摩擦力)の向きと同じ方向か、直角方向であること、
そしてほとんどの場合サイプ閉止端のコーナーから発生
していることを見出だした。
In order to investigate the cause of the above-mentioned sipe cracks and sip tears, the tires in which the sipe cracks and chippings have occurred were earnestly observed. According to it, the crack generation direction is the same direction as the direction of the stress (friction force) on the tire surface from the abrasion pattern on the tire surface, or the perpendicular direction,
And most of the time, I found that it originated from the corner of the closed end of the sipe.

【0007】このことから、タイヤ踏面部のサイプクラ
ックは、タイヤ踏面部に負荷が加わり、タイヤ表面の周
差に基づく周方向すべりによる力と、ゴムの垂直負荷に
より生じる撓みによるゴムの横方向移動に伴う横方向力
との合力が、タイヤ1回転ごとにサイプ閉止端のコーナ
ーに加わり、走行距離に比例する繰り返しでゴムが疲労
して生じるものと考えられる。またサイプ閉止端のコー
ナーは、サイプ幅が薄いこともあって、丸みが小さく、
応力の集中を起こし易い。応力集中はタイヤ踏面部のみ
ならず、サイプの底部にも生じる。
Therefore, the sipe crack on the tire tread portion causes a load to be applied to the tire tread portion, a force due to a circumferential slip caused by a circumferential difference of the tire surface, and a lateral movement of the rubber due to bending caused by a vertical load of the rubber. It is considered that the resultant force with the lateral force is applied to the corner of the closed end of the sipe every one rotation of the tire and the rubber fatigues due to repetition in proportion to the traveling distance. Also, the corner of the sipe closing end has a small roundness because the sipe width is thin,
It is easy to cause stress concentration. The stress concentration occurs not only on the tread surface of the tire but also on the bottom of the sipe.

【0008】この発明は、サイプクラック及びチッピン
グの生じる原因が、サイプ閉止端のコーナーに加わる応
力集中に起因することに鑑み、かかる応力集中を回避す
る手段として、サイプの閉止端を、90°を越える曲げ
角度θでなめらかな丸みをつけて曲げる構成を採用し
た。ここで曲げ角度θとは、折れ曲ったサイプ閉止端の
中央を通る仮想中心線が、サイプ開口端の中央を通るタ
イヤ回転軸方向の仮想中心線と交わる外角をいうものと
する。
In view of the fact that the cause of sipe cracking and chipping is due to the stress concentration applied to the corners of the sipe closing end, the present invention avoids such stress concentration by setting the closing end of the sipe to 90 °. We adopted a configuration that bends with a smooth roundness at a bending angle θ that exceeds. Here, the bending angle θ means an outer angle at which a virtual center line passing through the center of the bent sipe closed end intersects with a virtual center line in the tire rotation axis direction passing through the center of the sipe opening end.

【0009】他に応力集中を回避する手段として、サイ
プの閉止端を膨大して孔部を設ける構成も考えられる
が、タイヤ性能及び加工面から、孔の大きさにも限界が
あり、上記応力集中を回避する上で充分大きなアールを
得ることは困難である。
As another means for avoiding stress concentration, it is conceivable to construct a hole by enlarging the closed end of the sipe, but there is a limit to the size of the hole from the viewpoint of tire performance and processing, and the stress It is difficult to get a radius that is large enough to avoid concentration.

【0010】従って上述の通り、サイプの閉止端を、9
0°を越える曲げ角度θでなめらかな丸みをつけて曲げ
る構成が、タイヤ性能面及び加工面での要求も充足する
ことが同時にできるため最も有効な手段である。
Therefore, as described above, the closed end of the sipe is
The configuration of bending with a smooth roundness at a bending angle θ exceeding 0 ° is the most effective means because it can simultaneously satisfy the requirements in terms of tire performance and processing.

【0011】またサイプの閉止端を二股に分岐し、互い
に反対方向に、90°を越える曲げ角度θで、なめらか
な丸みをつけて曲げたサイプも採用できる。
Further, it is also possible to adopt a sipe which has a closed end which is bifurcated and which is bent in opposite directions at a bending angle θ of more than 90 ° with a smooth roundness.

【0012】ただ、分岐、非分岐のいずれの丸曲げサイ
プであっても、サイプの閉止端を90°以下の曲げ角度
θで曲げたサイプで構成した場合は、タイヤ周方向にお
いて隣接する他のサイプとの間にできた小ブロックに周
方向力が加わったとき、負荷はサイプ閉止端のコーナー
の小さなアール部分に加わり、従来と同様にタイヤ寿命
を下げる。
However, in both branched and non-branched round bending sipes, when the closing end of the sipes is formed by bending the sipes at a bending angle θ of 90 ° or less, the other sipes adjacent to each other in the tire circumferential direction are used. When a circumferential force is applied to the small block formed between the sipes, the load is applied to the small radius portion at the corner of the sipes closing end, and the tire life is shortened as in the conventional case.

【0013】また、上記いずれの丸曲げサイプも、サイ
プの閉止端における曲げ半径Rは、当該サイプのタイヤ
回転軸方向の長さHとの関係からは、サイプの閉止端が
0.08<R/H<0.3の範囲で設定することが望ま
しい。これは、このサイプをタイヤ踏面部に多数個、間
隔を置いて並べると、R/Hが0.08以下の場合で
は、サイプ長さあたりの曲げが不十分となり、負荷時、
疲労によるクラックが発生し易い。一方、R/Hが0.
3を越えた場合は、曲げ半径Rが大きくなる割に比べて
寿命の向上が少ない。
Further, in any of the above-described round bending sipes, the bending radius R at the closed end of the sipe is 0.08 <R at the closed end of the sipe from the relationship with the length H of the sipe in the tire rotation axis direction. It is desirable to set in the range of /H<0.3. This is because, when a large number of these sipes are arranged on the tire tread portion at intervals, when R / H is 0.08 or less, bending per sipe length becomes insufficient, and at the time of loading,
Cracks easily occur due to fatigue. On the other hand, R / H is 0.
When it exceeds 3, the life is not improved as much as the bending radius R increases.

【0014】なおこのサイプは、先端が曲がったブレー
ドをモールドに設置するだけで得られる。二股の両曲げ
サイプは、先端が曲がったブレードを、曲げ方向を反対
にして合わせてモールドに設置することで容易に成型で
きる。
This sipe can be obtained simply by installing a blade having a bent tip on the mold. The bifurcated bifurcated sipe can be easily molded by installing a blade having a bent tip in the mold with the bending directions reversed.

【0015】[0015]

【作用】この発明は、一端が開口し、他端が閉止するサ
イプを、タイヤ回転軸方向にほぼ平行に、かつタイヤ周
方向に間隔を置いて多数設置した重荷重用ラジアルタイ
ヤにおいて、上記サイプの閉止端が、90°を越える曲
げ角度θでなめらかな丸みをつけて曲げられている重荷
重用ラジアルタイヤであるので、走行中、タイヤ踏面部
に負荷が加わり、タイヤ表面の周差に基づく周方向すべ
りによる力と、ゴムの垂直負荷により生じる撓みによる
ゴムのタイヤ外向きの軸方向移動に伴う横方向力が合力
として作用しても、サイプ閉止端のコーナーへの応力集
中が著しく緩和され、ゴム疲労の発生を押さえることが
でき、サイプクラック及びサイプティアーの発生を防止
することができる。
The present invention provides a heavy-load radial tire in which a large number of sipes, one end of which is open and the other end of which is closed, are installed substantially parallel to the tire rotation axis direction and at intervals in the tire circumferential direction. The closed end is a heavy-duty radial tire that is bent with a smooth roundness at a bending angle θ of more than 90 °. Therefore, a load is applied to the tire tread during running, and the circumferential direction is based on the circumferential difference of the tire surface. Even if the force due to slippage and the lateral force due to the outward movement of the rubber in the tire axial direction due to the bending caused by the vertical load of the rubber act as the resultant force, the stress concentration at the corner of the sipe closing end is significantly alleviated, and the rubber It is possible to suppress the occurrence of fatigue and prevent the occurrence of sipe cracks and sipe tears.

【0016】[0016]

【実施例】図1はこの発明に係る重荷重用ラジアルタイ
ヤの一実施例を示すリブパターンの概略図であり、図2
はその要部拡大平面図である。
1 is a schematic view of a rib pattern showing an embodiment of a heavy duty radial tire according to the present invention.
[FIG. 3] is an enlarged plan view of a main part thereof.

【0017】図において、1はタイヤ踏面部、2はショ
ルダー接地端であり、タイヤ踏面部1にはタイヤ周方向
に連続して連なる主溝3が形成されている。4は、この
主溝3、3間に挟まれたリブ、5は主溝3とショルダー
接地端2に挟まれたショルダーリブである。6はショル
ダーリブ5のショルダー接地端2側にタイヤ周方向に設
けられた細溝である。
In the figure, 1 is a tire tread portion, 2 is a shoulder ground contact end, and a tire tread portion 1 is formed with a main groove 3 which is continuous in the tire circumferential direction. Reference numeral 4 is a rib sandwiched between the main grooves 3 and 3, and 5 is a shoulder rib sandwiched between the main groove 3 and the shoulder ground contact end 2. Reference numeral 6 denotes a narrow groove provided in the tire circumferential direction on the shoulder ground contact end 2 side of the shoulder rib 5.

【0018】7はショルダーリブ5に切り込まれたサイ
プであり、一端が細溝6の溝壁に開口し、他端が行き止
まり状態で閉止されている。該サイプ7の当該閉止端8
は、図2に示す通り、曲げ角度θ=170°、曲げ半径
R=0.6mmで、なめらかな丸みをつけて曲げられてお
り、このサイプ7は、細溝6の溝壁への開口端9から直
線部10、曲げ部11を経て閉止端8で終端している。
なおHはこのサイプのタイヤ回転軸方向の長さを示して
いる。
Reference numeral 7 is a sipe cut into the shoulder rib 5, one end of which is opened in the groove wall of the narrow groove 6 and the other end is closed in a dead end state. The closed end 8 of the sipe 7
2, is bent with a bending angle θ = 170 ° and a bending radius R = 0.6 mm with a smooth roundness, and this sipe 7 has an opening end of the narrow groove 6 to the groove wall. 9 through a straight line portion 10 and a bent portion 11 to terminate at a closed end 8.
H indicates the length of the sipe in the tire rotation axis direction.

【0019】従って、走行中、タイヤ踏面部に負荷が加
わり、タイヤ表面の周差に基づく周方向すべりによる力
と、ゴムの垂直負荷により生じる撓みによるゴムの横方
向移動に伴う横方向力が合力として当該サイプに作用し
ても、周方向力及び横方向力は、該サイプの曲げ部11
全体に作用するので、従来の様に、サイプ閉止端のコー
ナーに応力が集中することがなく、因ってゴム疲労の発
生を押さえることができ、サイプクラック及びチッピン
グを防止することができる。
Therefore, during running, a load is applied to the tire tread surface, and the force due to the circumferential slip due to the circumferential difference of the tire surface and the lateral force due to the lateral movement of the rubber due to the bending caused by the vertical load of the rubber are the resultant force. Even when acting on the sipe as a circumferential force and a lateral force, the bending portion 11 of the sipe is affected.
Since it acts on the whole, stress does not concentrate at the corner of the sipe closing end as in the prior art, and as a result, rubber fatigue can be suppressed and sipe cracking and chipping can be prevented.

【0020】因みに、上記実施例と同構造のタイサイズ
11R22.5のタイヤを用いて、それに曲げ半径Rと
サイプの長さHとの比(R/H)の異なる種々のサイプ
を設置し、その種々のサイプに対するクラックの発生の
し易さ又はし難さのテストを行った。すなわち直径の大
きい(約2m)、V=60Km/hで回転しているドラム
に、内圧700KPaで、使用リムサイズ7.5×2
2.5のタイヤを、規定負荷80%負荷(約2050K
g)、スリップ角0.5°にて押し付け、ドラムとの摩
擦力によってタイヤを回転せしめるドラムテストを実施
した。同テストの評価は、その優劣をクラック発生に至
るまでの走行距離(km)を測定し、従来サイプのタイ
ヤの走行距離に対する比をもって評価した。
By the way, using a tire of tie size 11R22.5 having the same structure as that of the above-mentioned embodiment, various sipes having different ratios (R / H) of the bending radius R and the length H of the sipes are installed on the tire. Tests were conducted on the ease or difficulty of crack formation for the various sipes. That is, a drum with a large diameter (about 2 m), rotating at V = 60 Km / h, an internal pressure of 700 KPa, and a rim size of 7.5 × 2 used.
2.5 tires, 80% load (about 2050K
g), a drum test was carried out in which the tire was rotated by pressing with a slip angle of 0.5 ° and frictional force with the drum. In the evaluation of the same test, the superiority or inferiority was measured by measuring the traveling distance (km) until the occurrence of cracks, and the ratio was compared with the traveling distance of the tire of the conventional sipe.

【0021】なおサイプは、タイヤ回転軸方向長さHが
3mm、深さが10mmであり、片側細溝サイドあたりのタ
イヤ1周に含まれる総数Nを470本としている。タイ
ヤに設置接地されたサイプには、そのタイヤ1回転ごと
に必ず1回接地(テストでは回転ドラム表面)すること
で負荷が与えれることになり、延べ回転数の増加と共
に、すなわち走行距離の増加と共に、ゴムが疲労し、R
/Hの小さい程、少ない走行距離でクラックの発生に至
る。
The sipes have a length H in the tire rotation axis direction of 3 mm and a depth of 10 mm, and the total number N of tires per one narrow groove side is 470. A load is applied to the sipe that is installed on the tire and is grounded once for each revolution of the tire (in the test, the surface of the rotating drum), so a load is applied, and as the total number of revolutions increases, that is, the mileage increases. At the same time, the rubber becomes tired and R
The smaller the value of / H, the smaller the distance traveled and the more cracks are generated.

【0022】その結果を図3に示す。図3はサイプ閉止
端における曲げ半径Rとサイプの長さHとの比(R/
H)とクラック発生に至るまでの走行距離(Km)との
関係を示す図である。図において、○は実施例、△は比
較例(R/H=0.03)を示している。
The results are shown in FIG. FIG. 3 shows the ratio (R / R) of the bending radius R and the length H of the sipe at the closed end of the sipe.
It is a figure which shows the relationship between H) and the traveling distance (Km) until it cracks. In the figure, ◯ indicates an example, and Δ indicates a comparative example (R / H = 0.03).

【0023】図3より、本実施例のタイヤは、比較例タ
イヤに比して、サイプの耐クラック性能が飛躍的に向上
することが認められる。また曲げ半径Rが大きくなるに
つれて耐クラック性能が向上することが認められる。
From FIG. 3, it can be seen that the tire of this example has a dramatically improved sipe crack resistance as compared with the comparative tire. It is also recognized that the crack resistance performance improves as the bending radius R increases.

【0024】次に図3に示された試験曲線により、実験
式を決定した結果、以下の通りとなった。
Next, as a result of determining the empirical formula from the test curve shown in FIG. 3, the results are as follows.

【0025】[0025]

【数1】N=32.9−89.5e-1/(1+R/H) ## EQU1 ## N = 32.9-89.5e -1 / (1 + R / H)

【0026】ここでNは、従来の比較例タイヤ(R/H
=0.03)の場合におけるクラック発生時の走行距離
を1としたときの、実施例タイヤの走行距離の倍率を示
している。
Here, N is a conventional comparative tire (R / H
= 0.03), the magnification of the running distance of the example tire is shown, where the running distance when cracks occur is 1.

【0027】従来の比較例タイヤの場合、サイプクラッ
クは、市場においてはおよそタイヤの摩耗寿命の1/4
〜1/8で発生していることから、少なくともタイヤの
摩耗寿命が尽きるまでの間、耐クラック寿命を延ばす必
要があり、それには少なくとも2.5〜8倍の耐クラッ
ク寿命とする必要がある(良路、定積以下、長時間走
行)。そこで上記の実験式を参考にして実用価値のある
R/Hを算定すると、R/Hは0.08、好ましくは
0.1以上あることが望ましいことになる。一方、R/
Hが0.3を越えた場合は、曲げ半径Rが大きくなる割
に比べて寿命の向上が少ない。
In the case of the conventional comparative tire, the sipe crack is about 1/4 of the wear life of the tire in the market.
Since it occurs at ~ 1/8, it is necessary to extend the crack resistance life at least until the wear life of the tire is exhausted, and it is necessary to make the crack resistance life at least 2.5 to 8 times. (Good road, less than constant volume, long running). Therefore, when R / H having practical value is calculated with reference to the above empirical formula, it is desirable that R / H is 0.08, preferably 0.1 or more. On the other hand, R /
When H exceeds 0.3, the life is not improved as much as the bending radius R increases.

【0028】ところでこの発明は上記の実施例に限定さ
れるものではない。例えば上記の実施例のサイプは、リ
ブパターンの重荷重用ラジアルタイヤを例にしている
が、ブロックパターン、リブブロックパターンなどのタ
イヤでも適用可能である。また上記サイプは細溝に開口
するサイプに対して適用した例であるが、主溝や副溝な
どの他の縦溝にも適用することができる。またバットレ
ス部からショルダー部の領域内に一端が開口するサイプ
にも適用できる。
The present invention is not limited to the above embodiment. For example, the sipe of the above-described embodiment is an example of a heavy tire radial tire having a rib pattern, but a tire having a block pattern, a rib block pattern, or the like is also applicable. Further, the sipe is an example applied to a sipe that opens in a narrow groove, but it can also be applied to other vertical grooves such as a main groove and a sub groove. It can also be applied to sipes whose one end opens from the buttress portion to the shoulder region.

【0029】また上記実施例は、閉止端を一方方向に曲
げた片曲げサイプとなっているが、図4および図5に示
す様に、サイプの閉止端12、13が、二股に分岐し、
互いに反対方向に、90°を越える曲げ角度θで、なめ
らかな丸みをつけて曲げられた両曲げサイプ14、15
であっても差支えない。なお、5、6は、前記実施例と
同符号で、それぞれ、ショルダーリブ、細溝である。
Further, in the above embodiment, the closed end is bent in one direction to form a one-sided sipe, but as shown in FIGS. 4 and 5, the closed ends 12 and 13 of the sipe are bifurcated,
Both bending sipes 14, 15 bent in opposite directions at a bending angle θ exceeding 90 ° with a smooth roundness
But it doesn't matter. Note that reference numerals 5 and 6 are the same as in the above-described embodiment, and are a shoulder rib and a narrow groove, respectively.

【0030】[0030]

【発明の効果】この発明は、一端が縦溝の溝壁等に開口
し、他端が閉止するサイプにおいて、当該サイプの閉止
端が、90°を越える曲げ角度θでなめらかな丸みをつ
けて曲げられているサイプを有する重荷重用ラジアルタ
イヤであるので、走行中、タイヤ踏面部に負荷が加わ
り、タイヤ表面の周差に基づく周方向すべりによる力
と、ゴムの垂直負荷により生じる撓みによるゴムの横方
向移動に伴う横方向力が作用しても、ゴム疲労の発生を
押さえることができ、サイプクラック及びサイプティア
ーの発生を防止することができる。
As described above, according to the present invention, in a sipe whose one end is opened to a groove wall of a vertical groove and the other end is closed, the closed end of the sipe is rounded smoothly with a bending angle θ exceeding 90 °. Since it is a heavy-duty radial tire with a bent sipe, a load is applied to the tire tread during running, and the force due to circumferential slip due to the circumferential difference of the tire surface and the rubber due to bending caused by vertical load on the rubber Even if a lateral force is applied along with the lateral movement, the occurrence of rubber fatigue can be suppressed, and the occurrence of sipe cracks and sipe tears can be prevented.

【図面の簡単な説明】[Brief description of drawings]

【図1】この発明に係る重荷重用ラジアルタイヤの一実
施例を示すリブパターンの概略図である。
FIG. 1 is a schematic view of a rib pattern showing an embodiment of a heavy duty radial tire according to the present invention.

【図2】同要部拡大平面図である。FIG. 2 is an enlarged plan view of the relevant part.

【図3】サイプ閉止端における曲げ半径Rとサイプの長
さHとの比(R/H)とクラック発生に至るまでの走行
距離との関係を示す図である。
FIG. 3 is a diagram showing a relationship between a ratio (R / H) of a bending radius R and a length H of a sipe at a closed end of a sipe, and a traveling distance until a crack is generated.

【図4】閉止端が二股に曲げられたサイプの一例を示す
要部拡大平面図である。
FIG. 4 is an enlarged plan view of an essential part showing an example of a sipe whose closed end is bent in two.

【図5】閉止端が二股に曲げられたサイプの他例を示す
要部拡大平面図である。
FIG. 5 is an enlarged plan view of an essential part showing another example of a sipe whose closed end is bent into two.

【符号の説明】[Explanation of symbols]

1 タイヤ踏面部 6 細溝 7 サイプ 8 閉止端 R サイプの曲げ半径 H サイプの長さ 12 閉止端 13 閉止端 14 サイプ 15 サイプ 1 Tire Tread 6 Small Groove 7 Sipe 8 Closed End R Sipe Bending Radius H Sipe Length 12 Closed End 13 Closed End 14 Sipe 15 Sipe

Claims (3)

【特許請求の範囲】[Claims] 【請求項1】タイヤ踏面部の縦溝、或はバットレス部か
らショルダー部の領域内に一端が開口し、他端が行き止
まり状態で閉止するサイプを、タイヤ回転軸方向にほぼ
平行に、かつタイヤ周方向に間隔を置いて多数設置した
重荷重用ラジアルタイヤにおいて、上記サイプの閉止端
が、90°を越える曲げ角度θでなめらかな丸みをつけ
て曲げられていることを特徴とする重荷重用ラジアルタ
イヤ。
1. A sipe whose one end opens in the vertical groove of the tire tread portion or in the region of the shoulder portion from the buttress portion, and the other end closes in a dead end, substantially parallel to the tire rotation axis direction, and the tire. A heavy-load radial tire having a large number of radial tires arranged at intervals in the circumferential direction, wherein the closed end of the sipe is bent with a smooth roundness at a bending angle θ exceeding 90 °. .
【請求項2】サイプの閉止端が二股に分岐し、互いに反
対方向に、90°を越える曲げ角度θで、なめらかな丸
みをつけて曲げられている請求項1記載の重荷重用ラジ
アルタイヤ。
2. The radial tire for heavy load according to claim 1, wherein the closed end of the sipe is bifurcated and bent in opposite directions at a bending angle θ of more than 90 ° with a smooth roundness.
【請求項3】サイプの閉止端における曲げ半径をR、当
該サイプのタイヤ回転軸方向の長さをHとした場合、サ
イプの閉止端が0.08<R/H<0.3の範囲で曲げ
られている請求項1又は2記載の重荷重用ラジアルタイ
ヤ。
3. When the bending radius at the closed end of the sipe is R and the length of the sipe in the tire rotation axis direction is H, the closed end of the sipe is in the range of 0.08 <R / H <0.3. The heavy-duty radial tire according to claim 1 or 2, which is bent.
JP5143168A 1993-06-15 1993-06-15 Heavy duty radial tire Withdrawn JPH071918A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP5143168A JPH071918A (en) 1993-06-15 1993-06-15 Heavy duty radial tire

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP5143168A JPH071918A (en) 1993-06-15 1993-06-15 Heavy duty radial tire

Publications (1)

Publication Number Publication Date
JPH071918A true JPH071918A (en) 1995-01-06

Family

ID=15332505

Family Applications (1)

Application Number Title Priority Date Filing Date
JP5143168A Withdrawn JPH071918A (en) 1993-06-15 1993-06-15 Heavy duty radial tire

Country Status (1)

Country Link
JP (1) JPH071918A (en)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2002055324A1 (en) * 2001-01-10 2002-07-18 Societe De Technologie Michelin Directional running tread comprising sipes with variable inclination
WO2010039148A1 (en) * 2008-10-03 2010-04-08 Societe De Technologie Michelin Undulated progressive tire mold element
US8869318B2 (en) 2007-12-12 2014-10-28 Hygie Canada Inc. Bedpan having a handle defined therein

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2002055324A1 (en) * 2001-01-10 2002-07-18 Societe De Technologie Michelin Directional running tread comprising sipes with variable inclination
US8869318B2 (en) 2007-12-12 2014-10-28 Hygie Canada Inc. Bedpan having a handle defined therein
WO2010039148A1 (en) * 2008-10-03 2010-04-08 Societe De Technologie Michelin Undulated progressive tire mold element

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