JP3329536B2 - Pneumatic radial tire for heavy loads - Google Patents
Pneumatic radial tire for heavy loadsInfo
- Publication number
- JP3329536B2 JP3329536B2 JP28663793A JP28663793A JP3329536B2 JP 3329536 B2 JP3329536 B2 JP 3329536B2 JP 28663793 A JP28663793 A JP 28663793A JP 28663793 A JP28663793 A JP 28663793A JP 3329536 B2 JP3329536 B2 JP 3329536B2
- Authority
- JP
- Japan
- Prior art keywords
- bead
- rubber
- bead portion
- ply
- pneumatic radial
- 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
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
- B60C15/00—Tyre beads, e.g. ply turn-up or overlap
- B60C15/06—Flipper strips, fillers, or chafing strips and reinforcing layers for the construction of the bead
- B60C15/0603—Flipper strips, fillers, or chafing strips and reinforcing layers for the construction of the bead characterised by features of the bead filler or apex
- B60C15/0607—Flipper strips, fillers, or chafing strips and reinforcing layers for the construction of the bead characterised by features of the bead filler or apex comprising several parts, e.g. made of different rubbers
-
- 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
- B60C15/00—Tyre beads, e.g. ply turn-up or overlap
- B60C15/06—Flipper strips, fillers, or chafing strips and reinforcing layers for the construction of the bead
- B60C2015/0614—Flipper strips, fillers, or chafing strips and reinforcing layers for the construction of the bead characterised by features of the chafer or clinch portion, i.e. the part of the bead contacting the rim
Landscapes
- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Tires In General (AREA)
Description
【０００１】[0001]
【産業上の利用分野】この発明は、重荷重用空気入りラ
ジアルタイヤに関し、特にトラック・バスなどの重車両
に使用される該タイヤが重荷重負荷の下で長距離、長時
間にわたる高速走行を度重ねることによりビ─ド部に生
じ勝ちなセパレ─ションなどの故障に対する抵抗力の増
強を、ビ─ド部に補強部材を追加することなく、したが
ってタイヤの重量増加なしに、タイヤの適合リムに接触
するビ─ド部区域に形成したゴムチェ─ファに工夫を加
えることにより有利に達成することを可能とする開発成
果を提案するものである。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pneumatic radial tire for heavy loads, and more particularly to a tire used for heavy vehicles such as trucks and buses, which is capable of running at high speed over a long distance and for a long time under heavy load. Increased resistance to failures such as separation, which are likely to occur in the bead due to overlapping, can be added to the compatible rim of the tire without adding reinforcing members to the bead, and therefore without increasing the weight of the tire. The present invention proposes a development result that can be advantageously achieved by devising a rubber chamfer formed in a contacting bead section area.
【０００２】[0002]
【従来の技術】トラック・バスなどの重車両に使用され
る重荷重用空気入りラジアルタイヤは、一対のビ─ド部
を有し、該ビ─ド部内に埋設したビ─ドコア相互間にわ
たってトロイド状に連なる、ラジアル配列のスチ─ルコ
─ドからなる少なくとも１プライのカ─カスと、該カ─
カスの外周に配設したベルトとを、上記ビ─ド部と、そ
れらに連なる一対のサイドウォ─ル部と、両サイドウォ
─ル部に連なるトレッド部とのボディ補強として具備
し、また上記ビ─ド部は、ビ─ドコアの周りを内側から
外側に折返したカ─カスのタ─ンアッププライと、ビ─
ドコアの外周側でカ─カスに沿って配設したスティフナ
─ゴムと、少なくともタ─ンアッププライの外面に沿っ
て配置した１層以上のコ─ド層からなるビ─ド部補強レ
イヤと、ビ─ド部に適合するリムに少なくとも接触する
区域に形成したゴムチェ─ファとを備えるのを慣例とし
ている。2. Description of the Related Art A heavy-duty pneumatic radial tire used for heavy vehicles such as trucks and buses has a pair of beads, and a toroidal shape extends between the bead cores embedded in the beads. At least one ply of a radially arranged steel cord connected to the carcass;
A belt disposed on the outer periphery of the waste as a body reinforcement for the bead portion, a pair of side wall portions connected to the bead portion, and a tread portion connected to both side wall portions; The bead part is a turn-up ply of a carcass that is folded around the bead core from inside to outside, and a bead.
A stiffener rubber disposed along the carcass on the outer peripheral side of the core, and a bead reinforcing layer comprising at least one or more code layers disposed at least along the outer surface of the turn-up ply; It is customary to have a rubber chamfer formed at least in the area of contact with the rim that fits the bead.
【０００３】ここに上記ゴムチェ─ファは、タイヤの重
荷重使用による負荷転動下でラジアルカ─カスの故にバ
イアスタイヤに比し変形がより一層激しくなることが余
儀なくされるビ─ド部の、タイヤに組合わせた適合リム
と接触する区域の磨滅（リム擦れ）量を極力抑制して、
ビ─ド部内における部材の露出阻止を専ら役務とするも
のであり、従ってゴムチェ─ファに対する要求特性は第
一に優れた耐磨耗性（耐リム擦れ性）であるとされてい
る。[0003] Here, the rubber chafer is a tire of a bead portion in which the deformation is further intensified as compared with a bias tire due to a radial arc under load rolling due to heavy use of the tire. Minimize the amount of wear (rim rubbing) in the area that comes in contact with the compatible rim combined with
The sole purpose of the service is to prevent the members from being exposed in the bead portion. Therefore, the characteristic required for the rubber chamfer is considered to be firstly excellent abrasion resistance (rim abrasion resistance).
【０００４】さらに上述したように、重荷重使用により
大変形が余儀なくされるビ─ド部は、カ─カスのタ─ン
アッププライ端部におけるセパレ─ションなどの故障発
生を阻止すべく、スティフナ─ゴムやビ─ド部補強レイ
ヤなどを配設して強化することを要し、その結果リムの
フランジに接触するビ─ド部部分は特に厚肉となり、こ
の部分の大変形と厚肉とがあいまって高温となる故、ゴ
ムチェ─ファには上記の優れた耐リム擦れ性と併せ十分
な耐熱劣化性を兼ね備えた物性を有するゴムストックの
適用が慣例とされ、これらの両物性を十分満たすゴムチ
ェ─ファであれば足りるとされていた。Further, as described above, the bead portion which is forced to undergo large deformation due to the use of a heavy load is provided with a stiffener in order to prevent a failure such as separation at the end of the turn-up ply of the carcass. It is necessary to arrange and strengthen rubber and bead reinforcing layers, and as a result, the bead portion that comes into contact with the rim flange is particularly thick, and large deformation and thick wall of this portion are required. As a result, it is customary to apply rubber stock to the rubber chair, which has physical properties that combine the above-mentioned excellent rim abrasion resistance with sufficient heat deterioration resistance, and sufficiently satisfy both of these physical properties. A rubber chef was said to be sufficient.
【０００５】ところが主としてタ─ンアッププライ端部
又はビ─ド部補強レイヤ端部における耐セパレ─ション
性に代表される重荷重用空気入りラジアルタイヤのビ─
ド部耐久性は必ずしも十分とは言えず、この耐久性向上
に対し一般にはスティフナ─ゴムの増量やビ─ド部補強
レイヤの層数増加により対処することを通例としてい
た。なおこの補強レイヤには有機繊維コ─ド層又はスチ
─ルコ─ド層を前者は複数層で、後者は単一層乃至前者
との複合層として充当するものである。However, a bead of a pneumatic radial tire for heavy load typified by separation resistance mainly at an end of a turn-up ply or an end of a bead reinforcing layer.
The durability of the bead portion is not always sufficient, and it is customary to cope with the improvement in durability by increasing the amount of stiffener rubber and increasing the number of bead portion reinforcing layers. The reinforcing layer is an organic fiber code layer or a steel code layer, the former being a plurality of layers, and the latter being a single layer or a composite layer with the former.
【０００６】[0006]
【発明が解決しようとする課題】反面上記のビ─ド部耐
久性の向上策はビ─ド部の重量増加を招くのは不可避で
あり、これは近来ますます強まるタイヤ軽量化要求にそ
ぐわない上発熱量の増加をもたらす不利を伴う。そこで
タイヤ軽量化を前提としてビ─ド部耐久性向上を図る対
象にスティフナ─ゴムの物性を取りあげ、ビ─ドコアの
直上に位置する硬質のスティフナ─ゴムの硬度を一層高
くしてビ─ド部の剛性を高めることや、この硬質スティ
フナ─ゴムに沿って配置する軟質のスティフナ─ゴムを
一層低ロス化することでビ─ド部温度の上昇を抑制する
ことが試みられたものの、何れの対策も要望に沿うビ─
ド部耐久性を達成するには至らなかった。On the other hand, the above measures for improving the durability of the bead portion inevitably cause an increase in the weight of the bead portion, which does not meet the increasing demand for lighter tires. With the disadvantage of increasing the heat value. Therefore, the physical properties of the stiffener rubber are taken as an object to improve the durability of the bead portion on the premise of reducing the weight of the tire, and the hardness of the hard stiffener rubber located immediately above the bead core is further increased to increase the bead portion. It has been attempted to increase the rigidity of the stiffener and to suppress the rise in the bead temperature by further reducing the loss of the soft stiffener rubber disposed along the hard stiffener rubber. Also meet demand
It did not reach to achieve the durability of the corner portion.
【０００７】上述した諸点に鑑み従来のビ─ド部耐久性
向上手段の延長から離れて発明者はゴムチェ─ファに着
目し、試みにゴムチェ─ファの内部に有機繊維コ─ド層
又はスチ─ルコ─ド層を埋設してビ─ド部耐久性を評価
したところ一段と優れた成績が得られることを見出し
た。そこでビ─ド部の軽量構造を保持した上で、ゴムチ
ェ─ファの物性に工夫を加えることによりビ─ド部耐久
性の向上を図ることがこの発明の目的である。In view of the above-mentioned points, apart from the conventional extension of the bead portion durability improving means, the inventor has focused on the rubber chafer, and tried to put an organic fiber code layer or a steeper inside the rubber chafer. When the bead durability was evaluated by embedding the record layer, it was found that superior results could be obtained. Accordingly, it is an object of the present invention to improve the durability of the bead portion by maintaining the lightweight structure of the bead portion and modifying the physical properties of the rubber chafer.
【０００８】[0008]
【課題を解決するための手段】上記目的を達成するため
この発明における重荷重用空気入りラジアルタイヤは、
一対のビ─ド部を有し、該ビ─ド部内に埋設したビ─ド
コア相互間にわたってトロイド状に連なる、ラジアル配
列のスチ─ルコ─ドからなる少なくとも１プライのカ─
カスと、該カ─カスの外周に配設したベルトとをボディ
補強として具備し、上記ビ─ド部が、ビ─ドコアの周り
を内側から外側に折返したカ─カスのタ─ンアッププラ
イと、ビ─ドコアの外周側でカ─カスに沿って配設した
スティフナ─ゴムと、少なくともタ─ンアッププライの
外面に沿って配置した１層以上のコ─ド層からなるビ─
ド部補強レイヤと、ビ─ド部に適合するリムに少なくと
も接触する区域に形成したゴムチェ─ファとを備えてな
る重荷重用空気入りラジアルタイヤにおいて、上記ゴム
チェ─ファが、２５℃、１００％伸長下において５５〜
９０kgf/cm2の範囲内である弾性率の値を有するゴムス
トックからなることを特徴とする。In order to achieve the above object, a heavy duty pneumatic radial tire according to the present invention comprises:
At least one ply of radially arranged steel cords having a pair of bead portions and extending in a toroidal manner between bead cores embedded in the bead portions.
A body and a belt disposed on the outer periphery of the carcass as a body reinforcement, and the bead portion turns up around the bead core from inside to outside. And a stiffener rubber disposed along the carcass on the outer peripheral side of the bead core, and at least one or more code layers disposed along the outer surface of the turn-up ply.
In a heavy-duty pneumatic radial tire comprising a bead portion reinforcing layer and a rubber chamfer formed at least in an area in contact with a rim adapted to the bead portion, the rubber chafer has a 100% elongation at 25 ° C. 55 below
It is characterized by comprising a rubber stock having a modulus of elasticity in the range of 90 kgf / cm 2 .
【０００９】図１にこの発明の重荷重用空気入りラジア
ルタイヤのビ─ド部断面の要部を示す。図において１は
ビ─ド部、２はビ─ド部１内に埋設した一対のビ─ドコ
ア（片側のみ示す）、３はビ─ドコア相互間にわたって
トロイド状に連なる、ラジアル配列のスチ─ルコ─ドか
らなる少なくとも１プライ（図の例は１プライ）のカ─
カス、３ｔはビ─ドコア２の周りを内側から外側に折返
したカ─カス３のタ─ンアッププライ、３ｔｅはその端
部を示す。ここにカ─カス３と、図示は省略したがカ─
カス３の外周に配設したベルト（２層以上のスチ─ルコ
─ド交差層からなる）とをボディ補強とし、このボディ
補強は一対のビ─ド部１と、やはり図示を省略した一対
のサイドウォ─ル部及びそれに連なるトレッド部とを補
強するものである。FIG. 1 shows an essential part of a bead section of a heavy-duty pneumatic radial tire according to the present invention. In the drawing, 1 is a bead portion, 2 is a pair of bead cores embedded in the bead portion 1 (only one side is shown), and 3 is a radially-arranged steel core connected in a toroidal shape between the bead cores. At least one ply of card (one ply in the example in the figure)
Reference numeral 3t denotes a turn-up ply of the carcass 3 which is turned around the bead core 2 from inside to outside, and reference numeral 3te denotes an end thereof. Here, the carcass 3 and the carcass 3, although not shown, are omitted.
A belt (consisting of two or more steel code cross layers) disposed on the outer periphery of the waste 3 is used as a body reinforcement, and the body reinforcement is made up of a pair of bead portions 1 and a pair of bead portions also not shown. It reinforces the side wall portion and the tread portion connected thereto.
【００１０】また図１において、４及び５はビ─ドコア
２の外周側にてカ─カス３に沿って配設したスティフナ
─ゴムであり、４は硬質スティフナ─ゴム、５が軟質ス
ティフナ─ゴムである。６は少なくともタ─ンアッププ
ライ３ｔの外面に沿って配置した１層以上のコ─ド層か
らなるビ─ド部補強レイヤであり、この図示例では２層
の有機繊維コ─ド層をカ─カス３本体の内面に沿う位置
まで巻上げた配置になる。７がゴムチェ─ファであり、
このゴムチェ─ファ７はビ─ド部１に適合する、換言す
ればこのビ─ド部１を有するタイヤに適合するリム１０
に少なくとも接触する区域に形成するものとする。ここ
に接触する区域とはタイヤ負荷の下でビ─ド部１がリム
のフランジ１０ｆに沿って外側に撓曲した状態において
接触する区域を含む。なお８はゴムチェ─ファ７と接合
されるサイドウォ─ルゴムであり、９はインナ─ライナ
である。In FIG. 1, reference numerals 4 and 5 denote stiffener rubber disposed along the carcass 3 on the outer peripheral side of the bead core 2. Reference numeral 4 denotes a hard stiffener rubber, and reference numeral 5 denotes a soft stiffener rubber. It is. Numeral 6 is a bead portion reinforcing layer composed of at least one code layer disposed at least along the outer surface of the turn-up ply 3t. In the illustrated example, two organic fiber code layers are formed.配置 It is arranged to be wound up to a position along the inner surface of the waste 3 main body. 7 is a rubber chef,
The rubber chamfer 7 is adapted to the bead portion 1, in other words, the rim 10 adapted to the tire having the bead portion 1.
Shall be formed at least in an area in contact with. The contact area includes an area where the bead portion 1 is bent outwardly along the rim flange 10f under a tire load. Reference numeral 8 denotes a side wall rubber to be joined to the rubber chamber 7, and 9 denotes an inner liner.
【００１１】ここにゴムチェ─ファ７は、２５℃、１０
０％伸長下における弾性率（以降Ｍ 100 と略す）の値が
５５〜９０kgf/cm2 の範囲内であるゴムストックからな
ることを要する。さらにこのゴムストックはＭ100 の値
が６５〜８０kgf/cm2 の範囲内であれば殊更望ましい。[0011] Here, the rubber chamber 7 is set at 25 ° C, 10
Elastic modulus under 0% elongation (hereinafter M 100Abbreviated)
55-90kgf / cmTwoFrom rubber stock that is in the range of
I need to do that. Furthermore, this rubber stock is M100The value of the
Is 65-80kgf / cmTwoIt is particularly desirable if the value is within the range of.
【００１２】上記Ｍ100 の値の範囲を有するゴムストッ
クは、ゴム単体１００PHR に対し例えばＨＡＦ級のカ─
ボンブラックを５０〜８５PHR （重量部）まで増量する
こと、硫黄を０．５〜６PHR 、より望ましくは０．７〜
４PHR 配合すること、そして例えばフェノ─ル樹脂、メ
ラミン樹脂などの熱硬化性樹脂を添加配合することによ
り好適に実現できる。なお硫黄の配合量については６PH
R が限界であり、この値をこえるとゴムストックが硬化
し過ぎてクラックや割れを惹起する不利がもたらされる
ので不所望である。The rubber stock having the above-mentioned range of M100 is, for example, a HAF grade of rubber per 100 PHR of rubber alone.
Bonbon black is increased to 50 to 85 PHR (parts by weight), sulfur is 0.5 to 6 PHR, more preferably 0.7 to
It can be suitably realized by blending 4 PHR and adding and blending a thermosetting resin such as a phenol resin or a melamine resin. The amount of sulfur is 6PH
R is the limit, and exceeding this value is undesirable because the rubber stock becomes too hard and gives rise to the disadvantage of causing cracks and cracks.
【００１３】[0013]
【作用】重荷重負荷の下、比較的高速で転動するタイヤ
のビ─ド部１は、全体として高温度となるのは避けがた
く、さらに常時高内圧（例えば７kgf/cm2 以上）が作用
している上、接地域においてはリム１０に強力に圧しつ
けられるため、車両の走行距離の増加に伴い、リム１０
と接触する区域のゴムチェ─ファ７には著しく大きなク
リ─プ歪εC が生じ勝ちになる。このクリ─プ歪εC の
うち特にリム１０のフランジ１０ｆに接触するゴムチェ
─ファ７部分におけるクリ─プ歪εC と、タ─ンアップ
プライ端部３ｔｅの歪との間に最も強い正相関の関係が
あることを発明者は見出した。[Action] It is unavoidable that the bead portion 1 of the tire, which rolls at a relatively high speed under heavy load, becomes high temperature as a whole, and furthermore, always has a high internal pressure (for example, 7 kgf / cm 2 or more). In addition, the rim 10 is strongly pressed against the rim 10 in the contact area.
The rubber chaper 7 in the area where it comes into contact with the substrate tends to generate a remarkably large clip strain ε C. The chestnut ─ strongest positive correlation between the chestnut ─ flop strain epsilon C in Gomuche ─ file 7 parts particularly in contact with the flange 10f of the rim 10 of the flop strain epsilon C, a distortion of the data ─ emissions up ply ends 3te The inventor has found that there is a relationship of
【００１４】上述したところはとりもなおさず、特にリ
ム１０のフランジ１０ｆに接触するゴムチェ─ファ７部
分におけるクリ─プ歪εC の抑制がタ─ンアッププライ
端部３ｔｅの歪を有利に抑制することに通じ、これは該
端部３ｔｅの耐セパレ─ション性の向上につながること
に他ならない。これは同時に、ビ─ド部１の補強レイヤ
６の端部についても同じ効果が得られることを意味す
る。In particular, the suppression of the creep strain ε C at the rubber chamfer 7 in contact with the flange 10f of the rim 10 advantageously suppresses the distortion of the turn-up ply end 3te. This leads to improvement of the separation resistance of the end 3te. This means that the same effect can be obtained at the end of the reinforcing layer 6 of the bead portion 1 at the same time.
【００１５】そこでゴムチェ─ファ７のＭ100 値に着目
し、それぞれ異なるＭ100 の値をもつゴムストックをゴ
ムチェ─ファ７に適用した、サイズが１０. ００Ｒ２０
１４ＰＲのトラック・バス用空気入りラジアルタイヤ
を、内圧９．０kgf/cm2 、負荷５０００kgの試験条件に
より５０００Ｋｍドラム走行させる実験を実施した後リ
ム解きし、図１にインフレート前の新品タイヤにおける
ゲ─ジＡにて示した位置の上記走行後ゴムチェ─ファ７
の肉厚Ａ′を測定したところ、Ｍ100 の値が５５kgf/cm
2 以上であればゴムチェ─ファ７は十分なゲ─ジを保持
し得ること、換言すれば上記クリ─プ歪εC は有効に抑
制可能であることが明らかなった。なお上記実験結果に
基づくＭ100 の値とゴムチェ─ファ７のゲ─ジＡ′との
関係を図２（ａ）のグラフに示す。[0015] Therefore, focusing on the M 100 value of Gomuche ─ file 7, the application of the rubber stock with a value of different M 100 each to Gomuche ─ file 7, size 10. 00R20
An experiment was conducted in which a 14 PR pneumatic radial tire for trucks and buses was run on a 5000 Km drum under a test condition of an internal pressure of 9.0 kgf / cm 2 and a load of 5000 kg, and then the rim was released. The rubber chef 7 after the running at the position indicated by page A
Measurement of the wall thickness A ', the value of M 100 is 55kgf / cm
If it is 2 or more, it is clear that the rubber chaper 7 can hold a sufficient gauge, in other words, the above-mentioned creep strain ε C can be effectively suppressed. Incidentally shown in the graph shown in FIG. 2 (a) the relationship between the M 100 value and Gomuche ─ fan 7 of gate ─ di A 'based on the above experimental results.
【００１６】上記クリ─プ歪εC が有効に抑制される結
果、図２（ｂ）のグラフに示すように、ビ─ドコア２と
リム１０のフランジ１０ｆとの間の隔たりＢの、走行初
期からの変位量ΔＢが小さく抑えられる。ここに変位量
ΔＢはタイヤの接地域にてタ─ンアッププライ端部３ｔ
ｅに発生する歪に顕著な影響を及ぼし、該端部３ｔｅに
おける歪は、相対的に大きな変位量ΔＢの場合は著しく
増加し、小さな変位量ΔＢではこの増加が低く抑えられ
る傾向を示す。なお上記隔たりＢ及び変位量ΔＢは、タ
イヤをリム組みしインフレートした状態で例えばＣＴス
キャンなどにより測った値を用いたもので、以降も同様
である。As a result of the effective suppression of the above-mentioned creep strain ε C , as shown in the graph of FIG. 2 (b), the distance B between the bead core 2 and the flange 10 f of the rim 10 increases at the beginning of traveling. The amount of displacement ΔB from is reduced. Here, the displacement amount ΔB is 3 tons of the turn-up ply end in the contact area of the tire.
This has a remarkable effect on the distortion generated in e, and the distortion at the end 3te increases remarkably when the displacement ΔB is relatively large, and tends to be suppressed low when the displacement ΔB is small. Note that the distance B and the displacement amount ΔB use values measured by, for example, a CT scan or the like in a state where the tire is mounted on a rim and inflated, and the same applies to the following description.
【００１７】よってＭ100 の値が５５kgf/cm2 以上、よ
り望ましくは６５kgf/cm2 以上であるゴムストックをゴ
ムチェ─ファ７に適用することにより、小さな変位量Δ
Ｂを保持し、タ─ンアッププライ端部３ｔｅに発生する
歪の増加を有効に抑制することができるので、その結果
補強部材の追加によらず、従って重量を増すことなくビ
─ド部のセパレ─ション耐久性の格段の向上が達成でき
る。なおＭ100 の値が９０kgf/cm2 をこえると切断伸び
が小さくなり過ぎる結果、クラックや割れが生じ勝ちに
なり、これが耐セパレ─ション性に対し悪影響を及ぼす
ので不所望である。Therefore, by applying a rubber stock having a value of M 100 of 55 kgf / cm 2 or more, more desirably 65 kgf / cm 2 or more, to the rubber chamber 7, a small displacement Δ
B can be effectively suppressed from increasing the distortion generated at the end 3te of the turn-up ply. As a result, the bead portion can be formed without increasing the weight of the reinforcing member and thus without increasing the weight. Dramatic improvement in separation durability can be achieved. Incidentally result the value of M 100 there is an elongation at break exceeds 90 kgf / cm 2 becomes too small, it becomes a crack and breakage occur wins, this is undesirable is because an adverse effect to the anti-separator ─ Deployment properties.
【００１８】[0018]
【実施例】サイズが１０．００Ｒ２０ １４ＰＲであ
り、ラジアル配列のスチ─ルコ─ドからなる１プライの
カ─カス３と、４層のスチ─ルコ─ド交差層からなるベ
ルトとをボディ補強とし、ビ─ド部１は図１に準じ、硬
質スティフナ─ゴム４はJIS硬度８４のゴムストック、
軟質スティフナ─ゴム５はJIS 硬度６５のゴムストック
からなり、ビ─ド部補強レイヤ６は１層のスチ─ルコ─
ド交差層からなる。ゴムチェ─ファ７は図１に示すゲ─
ジＡを３ｍｍ、ビ─ドコア２とフラン１０ｆとの隔たり
Ｂを６ｍｍとした。DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A 1 ply carcass 3 consisting of radially arranged steel cords and a belt consisting of four layers of steel cord cross layers are used as a body reinforcement. The bead portion 1 is as shown in FIG. 1, and the hard stiffener rubber 4 is a rubber stock of JIS hardness 84,
The soft stiffener rubber 5 is made of rubber stock having a JIS hardness of 65, and the bead reinforcing layer 6 is a one-layer steel core.
It consists of a crossing layer. The rubber buffer 7 is a gate shown in FIG.
The gap A was 3 mm, and the gap B between the bead core 2 and the furan 10f was 6 mm.
【００１９】上記を共通としゴムチェ─ファ７のゴムス
トックの配合組成のみ異なる実施例１〜５及び比較例
１、２、３のタイヤを準備した。これらのゴムストック
の配合例を表１に示す。なお表中、各配合剤につき示し
た数値は重量部数（PHR)であり、中段に示したＭ100 は
２５℃における１００％伸長時弾性率である。Tires of Examples 1 to 5 and Comparative Examples 1, 2, and 3 having the same components as above but differing only in the composition of the rubber stock of the rubber buffer 7 were prepared. Table 1 shows examples of the composition of these rubber stocks. In the table, the numerical values shown for each compounding agent are parts by weight (PHR), and M 100 shown in the middle row is the elastic modulus at 25 ° C. at 100% elongation.
【００２０】[0020]
【表１】 [Table 1]
【００２１】この発明の効果を検証するため上記実施例
１〜５及び比較例１、２、３の各タイヤを供試タイヤと
して、内圧９．０kgf/cm2 、負荷５０００Ｋｇ、速度６
０Km/hの試験条件にてドラム走行試験を実施し、まず５
０００Ｋｍ走行後におけるゲ─ジＡ部分の残ゲ─ジＡ′
（ｍｍ）、ビ─ドコア２のリムフランジ１０ｆに向かう
変位量ΔＢ（ｍｍ）及びタ─ンアッププライ端部３ｔｅ
の歪を測定した。なおこれらの測定はビ─ド部１をその
円周まわりにほぼ８等分した各位置にて実施し、得られ
た値の平均値を取り上げた。次に別途、上記と同じ供試
タイヤを上記と同一試験条件下でビ─ド部１にセパレ─
ションが発生するまで走行させるビ─ド部耐久試験を実
施した。なお耐久試験が終了した各供試タイヤは全数ゴ
ムチェ─ファ７のクラック又は割れの有無をチェックし
た。In order to verify the effects of the present invention, the tires of Examples 1 to 5 and Comparative Examples 1, 2, and 3 were used as test tires, with an internal pressure of 9.0 kgf / cm 2 , a load of 5000 kg, and a speed of 6 kg.
A drum running test was performed under the test conditions of 0 km / h.
Remaining gage A 'of gage A after running 000 km
(Mm), the displacement amount ΔB (mm) of the bead core 2 toward the rim flange 10f, and the turn-up ply end 3te
Was measured. Note that these measurements were performed at each position where the bead portion 1 was divided into approximately eight equal parts around the circumference thereof, and the average value obtained was taken. Next, separately, the same test tire as above is separated into the bead portion 1 under the same test conditions as above.
A bead endurance test was conducted to run the vehicle until a collision occurred. Each of the test tires for which the durability test was completed was checked for cracks or cracks in all the rubber chafers 7.
【００２２】上記の試験結果を表１の下欄に示す。表
中、タ─ンアッププライ端部３ｔｅの歪及びセパレ─シ
ョン発生までに走行した距離は比較例１を１００とする
指数にてあらわし、前者は数値が小さいほど良く、後者
は大きいほど良いことを示す。またクラック又は割れに
ついては、無しを○、有りを×にてあらわし、後者は何
れも深くかつ多数のクラック又は割れが観察されてい
る。The test results are shown in the lower column of Table 1. In the table, the distortion of the turn-up ply end 3te and the distance traveled before the occurrence of separation are represented by an index with Comparative Example 1 being 100. The former is better as the numerical value is smaller, and the latter is better as the value is larger. Is shown. Regarding cracks or cracks, the absence and the presence of a crack are represented by ○ and ×, respectively, and in each case, a large number of cracks or cracks are observed.
【００２３】表１が示すように、比較例１に対しビ─ド
コア２の変位量ΔＢが少ない各実施例のタイヤはビ─ド
部１のセパレ─ション耐久性が一段と向上し、この点で
は比較例２、３のタイヤも同様に向上している反面、ゴ
ムチェ─ファ７にクラックや割れの発生が認められた。
このクラックや割れがそれ自体の故障に止まっているの
は、短時間でビ─ド部セパレ─ション故障を発生させる
ドラム試験によるものであり、実際の長距離、長期間に
わたる重車両使用ではビ─ド部補強レイヤ６などのセパ
レ─ションに発展してビ─ド部１の耐久性を大きく損な
う故不可である。これに対しＭ100 の値を９０kgf/cm2
以下に抑えた実施例のタイヤにはこのうれいはない。As shown in Table 1, in each of the tires of the examples in which the displacement amount ΔB of the bead core 2 was smaller than that of the comparative example 1, the separation durability of the bead portion 1 was further improved. The tires of Comparative Examples 2 and 3 were similarly improved, but cracks and cracks were observed in the rubber buffer 7.
The reason why these cracks and cracks are not limited to the failure itself is due to a drum test that causes a bead separation failure in a short time. This is not possible because it develops into a separation such as the bead portion reinforcing layer 6 and the durability of the bead portion 1 is greatly impaired. 90kgf the value of the M 100 the other hand / cm 2
The tires of the embodiments described below do not have this joy.
【００２４】[0024]
【発明の効果】この発明によれば、ビ─ド部に補強部材
を付加することなくタイヤの軽量化を保持して、ビ─ド
部のセパレ─ション耐久性を有利に向上することが可能
な重荷重用空気入りラジアルタイヤを提供できる。According to the present invention, it is possible to maintain the weight reduction of the tire without adding a reinforcing member to the bead portion and to advantageously improve the separation durability of the bead portion. A heavy pneumatic radial tire for heavy loads can be provided.
【図１】この発明の要部を示す断面図である。FIG. 1 is a sectional view showing a main part of the present invention.
【図２】ゴムチェ─ファの１００％伸長時弾性率と変形
との関係を説明する線図である。FIG. 2 is a diagram illustrating the relationship between the elastic modulus at 100% elongation and deformation of a rubber chafer.
１ ビ─ド部 ２ ビ─ドコア ３ カ─カス ７ ゴムチェ─ファ 1 bead section 2 bead core 3 carcass 7 rubber chair
───────────────────────────────────────────────────── フロントページの続き (56)参考文献 特開 平２−53614（ＪＰ，Ａ) 特開 平２−179515（ＪＰ，Ａ) 特開 平３−125612（ＪＰ，Ａ) 特開 平５−320423（ＪＰ，Ａ) 特開 平７−172118（ＪＰ，Ａ) 特開 昭60−38213（ＪＰ，Ａ) 特開 昭59−84608（ＪＰ，Ａ) 米国特許5085260（ＵＳ，Ａ) (58)調査した分野(Int.Cl.7，ＤＢ名) B60C 15/00,15/06 ────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-2-53614 (JP, A) JP-A-2-179515 (JP, A) JP-A-3-125612 (JP, A) JP-A-5-205 320423 (JP, A) JP-A-7-172118 (JP, A) JP-A-60-38213 (JP, A) JP-A-59-84608 (JP, A) US Patent 5,085,260 (US, A) (58) Field surveyed (Int. Cl. 7 , DB name) B60C 15/00, 15/06
Claims (1)
埋設したビ─ドコア相互間にわたってトロイド状に連な
る、ラジアル配列のスチ─ルコ─ドからなる少なくとも
１プライのカ─カスと、該カ─カスの外周に配設したベ
ルトとをボディ補強として具備し、上記ビ─ド部が、ビ
─ドコアの周りを内側から外側に折返したカ─カスのタ
─ンアッププライと、ビ─ドコアの外周側でカ─カスに
沿って配設したスティフナ─ゴムと、少なくともタ─ン
アッププライの外面に沿って配置した１層以上のコ─ド
層からなるビ─ド部補強レイヤと、ビ─ド部に適合する
リムに少なくとも接触する区域に形成したゴムチェ─フ
ァとを備えてなる重荷重用空気入りラジアルタイヤにお
いて、 上記ゴムチェ─ファが、２５℃、１００％伸長下におい
て５５〜９０kgf/cm2の範囲内である弾性率の値を有す
るゴムストックからなることを特徴とする重荷重用空気
入りラジアルタイヤ。1. A car having at least one ply of radially arranged steel cords having a pair of bead portions and extending in a toroidal manner between bead cores embedded in the bead portions. A body and a belt disposed on the outer periphery of the carcass as a body reinforcement, and the bead portion turns up around the bead core from inside to outside. A stiffener rubber disposed along the carcass on the outer peripheral side of the bead core; and a bead portion comprising at least one or more code layers disposed at least along the outer surface of the turn-up ply. A heavy-duty pneumatic radial tire comprising a reinforcing layer and a rubber chamfer formed at least in an area in contact with a rim adapted to a bead portion, wherein the rubber chafer is at 25 ° C and 100% elongation. 55-9 heavy duty pneumatic radial tire characterized by comprising a rubber stock having a value of elastic modulus in the range of kgf / cm 2.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP28663793A JP3329536B2 (en) | 1993-11-16 | 1993-11-16 | Pneumatic radial tire for heavy loads |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP28663793A JP3329536B2 (en) | 1993-11-16 | 1993-11-16 | Pneumatic radial tire for heavy loads |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH07137507A JPH07137507A (en) | 1995-05-30 |
| JP3329536B2 true JP3329536B2 (en) | 2002-09-30 |
Family
ID=17706999
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP28663793A Expired - Lifetime JP3329536B2 (en) | 1993-11-16 | 1993-11-16 | Pneumatic radial tire for heavy loads |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP3329536B2 (en) |
Families Citing this family (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US7819155B2 (en) | 2004-03-25 | 2010-10-26 | Sumitomo Rubber Industries, Ltd. | Rubber composition for tire and pneumatic tire using the same |
| JP5201941B2 (en) * | 2007-10-19 | 2013-06-05 | 株式会社ブリヂストン | Pneumatic radial tire for heavy loads |
| FR2948605B1 (en) * | 2009-07-30 | 2011-08-12 | Michelin Soc Tech | PNEUMATIC VEHICLE FOR HEAVY WEIGHT HAVING REINFORCED BOURRELET. |
| JP7181159B2 (en) * | 2019-06-21 | 2022-11-30 | 株式会社ブリヂストン | tire |
Family Cites Families (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5984608A (en) * | 1982-11-04 | 1984-05-16 | Sumitomo Rubber Ind Ltd | Radial tire |
| JPS6038213A (en) * | 1983-08-09 | 1985-02-27 | Sumitomo Rubber Ind Ltd | Radial tire for heavy vehicle |
| JPH0253614A (en) * | 1988-08-18 | 1990-02-22 | Bridgestone Corp | Large vehicle tire |
| US5085260A (en) * | 1988-12-28 | 1992-02-04 | Sumitomo Rubber Industries, Ltd. | Heavy duty radial tire with a carcass turnup portion having specific dimensions |
| JPH02179515A (en) * | 1988-12-30 | 1990-07-12 | Yokohama Rubber Co Ltd:The | Radial tire |
| JPH03125612A (en) * | 1989-10-11 | 1991-05-29 | Yokohama Rubber Co Ltd:The | Pneumatic tire for passenger car |
| JPH05320423A (en) * | 1992-05-27 | 1993-12-03 | Bridgestone Corp | Pneumatic low-noise tire |
| JP3437235B2 (en) * | 1993-12-21 | 2003-08-18 | 株式会社ブリヂストン | Aircraft radial tires |
-
1993
- 1993-11-16 JP JP28663793A patent/JP3329536B2/en not_active Expired - Lifetime
Also Published As
| Publication number | Publication date |
|---|---|
| JPH07137507A (en) | 1995-05-30 |
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