JPH08113017A - Pneumatic radial tire - Google Patents
Pneumatic radial tireInfo
- Publication number
- JPH08113017A JPH08113017A JP6250987A JP25098794A JPH08113017A JP H08113017 A JPH08113017 A JP H08113017A JP 6250987 A JP6250987 A JP 6250987A JP 25098794 A JP25098794 A JP 25098794A JP H08113017 A JPH08113017 A JP H08113017A
- Authority
- JP
- Japan
- Prior art keywords
- tire
- cord
- carcass
- carcass layer
- layer
- 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.)
- Pending
Links
Landscapes
- Tires In General (AREA)
- Artificial Filaments (AREA)
Abstract
Description
【0001】[0001]
【産業上の利用分野】本発明は、カ−カス層を構成する
コ−ド材としてモノフィラメントコ−ドを用いた空気入
りラジアルタイヤに関し、特にモノフィラメントコ−ド
の特質に由来する耐久性の低下を防止するタイヤに関す
る。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pneumatic radial tire using a monofilament code as a cord material for forming a carcass layer, and particularly, the durability is lowered due to the characteristics of the monofilament code. For tires to prevent.
【0002】[0002]
【従来の技術】高弾性率と低熱収縮率との両特性を具え
た有機繊維コ−ドをカ−カス材として用いた空気入りラ
ジアルタイヤは、優れた操縦安定性の発揮や内圧充填時
のサイドウオ−ル部表面の凹凸抑制に有利であることが
良く知られている。このような特性を持つ有機繊維コ−
ドとして、レ−ヨンコ−ド(但し、多数のフィラメント
撚り合わせた所謂マルチフィラメントコ−ド)を使用し
たラジアルタイヤが提供されている。しかるに、レ−ヨ
ンコ−ドの使用の場合、原料パルプの省資源問題やコ−
ド生産工程での環境保全上の問題やレ−ヨンコ−ドの高
い吸湿性に由来するタイヤ製造時の工程管理の煩雑さな
どの不利な面が存在する。2. Description of the Related Art A pneumatic radial tire using as a carcass material an organic fiber cord having both a high elastic modulus and a low heat shrinkage rate is excellent in steering stability and in filling with internal pressure. It is well known that it is advantageous for suppressing unevenness on the surface of the side wall portion. Organic fiber core with such characteristics
As a cord, a radial tire using a rayon cord (however, a so-called multifilament cord in which a large number of filaments are twisted) is provided. However, when using rayon cords, the resource saving problem of raw pulp and cord
There are disadvantages such as environmental conservation problems in the production process and complexity of process control during tire production due to the high hygroscopicity of the rayon cord.
【0003】そこで、レ−ヨン代替えコ−ドの開発が進
められ各種の新規高分子繊維材が提案されたが、現状で
は高弾性率及び低熱収縮性の特性を持つ繊維剤としては
ポリエステル系合成繊維のみがタイヤカ−カス用コ−ド
材料として実用に供されている。しかも、タイヤカ−カ
ス用コ−ドに使用する際は、フイラメント(極細繊維
糸)を束ねて3〜6デニ−ル(符号Dで表し、繊維90
00m当たりのグラム数)のヤ−ンとしたものを多数本
集束して例えば1000D以上のマルチヤ−ン集束体の
下撚糸とし、更にこの下撚糸2本を方向を変えて撚り合
わせ1000D/2のコ−ドとするか又は下撚糸3本を
方向を変えて撚り合わせ1000D/3のコ−ドとする
のが従来一般的である。Under the circumstances, development of a rayon-replacement cord has been promoted and various new polymer fiber materials have been proposed. At present, polyester-based synthetic materials are used as a fiber agent having high elastic modulus and low heat shrinkability. Only fibers have been put to practical use as a cord material for tire carcass. Moreover, when it is used for a tire carcass cord, filaments (ultrafine fiber yarns) are bundled to form 3 to 6 denier (denoted by symbol D, fiber 90).
A large number of yarns (grams per 00 m) are bundled to form a lower twisted yarn of a multi-yarn bundle of, for example, 1000D or more, and the two twisted yarns are changed in direction and twisted for 1000D / 2. It has been customary to use a cord or a twist of three lower twisted yarns in different directions to form a cord of 1000D / 3.
【0004】一方、フィラメントの収束体を上述の如く
撚り合わせる工程を省略し製造能率向上と製造コスト低
減を図ろうとする意図の基に、一本のフィラメントから
成るコ−ド、所謂モノフィラメントコ−ドの開発が行わ
れている。このモノフィラメントコ−ドは、コ−ド構造
上の特質から前記のマルチフィラメントコ−ドに比較し
て高弾性率及び低熱収縮性の特性を更に高めることが予
想されることから、タイヤカ−カスコ−ドへの採用が試
みられ、当初は疲労性に優れるナイロンのモノフィラメ
ントコ−ドが検討されたが、所望の高弾性率及び低熱収
縮性の特性が得られず、やはり材質はポリエステル系の
ものが適していることが確認され、例えば、特開平3−
185111号公報では低カルボキシル基ポリエステル
繊維材を適用したポリエステルモノフィラメントコ−ド
を、また特開平4−232102号公報ではスチ−ム加
熱延伸により得たポリエステルモノフィラメントコ−ド
をタイヤに適用する旨の開示が見られる。On the other hand, a cord made of one filament, a so-called monofilament cord, is intended to improve the production efficiency and reduce the production cost by omitting the step of twisting the filament bundles as described above. Is being developed. This monofilament code is expected to further enhance the characteristics of high elastic modulus and low heat shrinkability as compared with the above-mentioned multifilament code due to the characteristics of the code structure. At first, a nylon monofilament cord having excellent fatigue properties was studied, but the desired high elastic modulus and low heat shrinkability were not obtained, and the polyester material was also used. It was confirmed to be suitable, and for example, Japanese Patent Laid-Open No.
Japanese Patent No. 185111 discloses a polyester monofilament cord applied with a low carboxyl group polyester fiber material, and Japanese Laid-Open Patent Publication No. 4-232102 discloses a polyester monofilament cord obtained by steam heat drawing applied to a tire. Can be seen.
【0005】[0005]
【発明が解決しようとする課題】しかるに、ポリエステ
ルを主体とするモノフィラメントコ−ドは確かに優れた
高弾性率及び低熱収縮性の特性を示すものの、一方でこ
の種のコ−ドでは、分子鎖間力が著しく小さいことに由
来するフィブリル化(ささくれだち)によってタイヤコ
−ドに圧縮歪みを受けた場合にコ−ドが疲労破壊を起こ
し易いことと、マルチフィラメント撚りコ−ドの場合に
撚り角度をもつ一本毎の極細フィラメントが撓曲変形に
よってタイヤコ−ドに入力される圧縮歪みを吸収緩和す
る機能を持つのに対しこの様な機能がコ−ド構造上期待
できないことから、結局マルチフィラメントの撚りコ−
ドに比較してモノフィラメントコ−ドの耐走行疲労性は
著しく劣ると言う問題があってカ−カスプライにポリエ
ステルモノフィラメントコ−ドを適用したタイヤは未だ
実用化がなされていないのが現状である。However, while the monofilament cord mainly composed of polyester certainly exhibits excellent characteristics of high elastic modulus and low heat shrinkage, on the other hand, in this type of cord, the molecular chain is When the tire cord is subjected to compressive strain due to fibrillation due to the extremely small inter-force, the cord is prone to fatigue fracture and twisting in the case of a multi-filament twist cord While each angled ultrafine filament has the function of absorbing and relaxing the compressive strain input to the tire code due to flexural deformation, such a function cannot be expected due to the code structure. Filament twist
The running fatigue resistance of the monofilament cord is remarkably inferior to that of the cord, so that the tire in which the polyester monofilament cord is applied to the carcass ply has not yet been put to practical use.
【0006】従って、本発明の目的は、ポリエステルモ
ノフィラメントコ−ドをタイヤカ−カスプライに適用し
た場合のポリエステルコ−ド固有の欠点であるタイヤ走
行による耐疲労性の低下を防止して、タイヤの操縦安定
性や転がり抵抗等のタイヤ性能を向上し又サイドウオ−
ル部表面の内圧充填時の凹凸を抑制してタイヤ外観を改
良する空気入りラジアルタイヤを提供することである。Therefore, an object of the present invention is to prevent the deterioration of fatigue resistance due to running of the tire, which is a drawback peculiar to the polyester cord when the polyester monofilament cord is applied to the tire carcass ply, and to control the tire. Improves tire performance such as stability and rolling resistance.
It is an object of the present invention to provide a pneumatic radial tire that improves the tire appearance by suppressing the unevenness on the surface of the inner surface of the inner wall during filling with internal pressure.
【0007】[0007]
【課題を解決するための手段】上記の目的を達成するた
めに、本発明の空気入りラジアルタイヤでは、特許請求
項1に記載の如く、左右に間隔をとって配置される一対
のリング状ビ−ドコアと、両端が該ビ−ドコアに巻回さ
れて折り返され中央部が円環体状に形成されたカ−カス
層と、該カ−カス層中央部の頭頂部のタイヤ径方向外側
に複数枚積層された帯状のベルト層とを主補強構造とし
て、前記帯状のベルト層のタイヤ径方向外側にリング状
のトレッドゴムが配置され、該トレッドゴムの両側に前
記カ−カス層を覆って左右一対のサイドゴムが配置さ
れ、しかも、前記カ−カス層が複数のポリエステルモノ
フィラメントコ−ドがタイヤの赤道面に対してほぼ直角
方向に並列されて被覆ゴム中に埋設されて成る空気入り
ラジアルタイヤであって、タイヤの回転軸方向の内側か
ら外側に向かってビ−ドコア回りに巻回し折り返された
カ−カス層折り返し部のビ−ド部分の形状が、タイヤの
ト−タル厚さをAとしタイヤの外壁からカ−カス層折り
返し部のコ−ドまでの距離をBとする時、B/A>0.
5を満足する様に形成され、且つ前記カ−カス層が固有
粘度が0.75以上のポリエステルモノフィラメントコ
−ドから成ることを特徴とするとしている。また、強度
上タイヤカ−カスプライの枚数が増加してタイヤ重量の
増加をもたらさない様にするために、カ−カスを構成す
る前記ポリエステルモノフィラメントコ−ドの繊度が1
000デニ−ル以上である特許請求項1に記載の空気入
りラジアルタイヤとしている。In order to achieve the above object, in the pneumatic radial tire of the present invention, as described in claim 1, a pair of ring-shaped belts arranged at right and left intervals are provided. -A core, a carcass layer whose both ends are wound around the bead core and folded back, and a central portion of which is formed in an annular shape, and a crown portion of the central portion of the carcass layer on the tire radial outside. As a main reinforcing structure with a plurality of belt-shaped belt layers laminated, a ring-shaped tread rubber is arranged on the outer side in the tire radial direction of the belt-shaped belt layer, and the carcass layer is covered on both sides of the tread rubber. A pneumatic radial tire in which a pair of left and right side rubbers are arranged, and further, the carcass layer is embedded in a coated rubber by arranging a plurality of polyester monofilament cords in a direction substantially perpendicular to the equatorial plane of the tire. And Thus, the shape of the bead portion of the carcass layer turnback portion, which is wound around the bead core and turned back from the inner side to the outer side in the rotation axis direction of the tire, has a total thickness of the tire as A and the tire Where B is the distance from the outer wall to the cord of the carcass layer turnaround portion, B / A> 0.
5, the carcass layer is made of a polyester monofilament cord having an intrinsic viscosity of 0.75 or more. In order to prevent the increase in the number of tire carcass plies and the increase in tire weight in terms of strength, the polyester monofilament cord constituting the carcass has a fineness of 1 or less.
The pneumatic radial tire according to claim 1, which has a denier of 000 or more.
【0008】なお、カ−カスプライ層に使用されるポリ
エステルモノフィラメントコ−ドは、ポリエステル単体
から構成されたものでも又2層構造以上の所謂芯鞘構造
をとるものであっても構わない。但し、前述した如く、
高モジュラス、低熱収縮特性がモノフィラメントコ−ド
の特長であるので、タイヤから取り出したコ−ドモジュ
ラスが成るべく高いモノフィラメントコ−ドが好まし
い。The polyester monofilament cord used for the carcass ply layer may be composed of a single polyester or may have a so-called core-sheath structure having two or more layers. However, as mentioned above,
Since the monofilament code has the characteristics of high modulus and low heat shrinkage, the monofilament code having a high code modulus taken out from the tire is preferable.
【0009】また、本発明においては、前記カ−カス層
折り返し部のビ−ド部分とは、ホイ−ルに装着されて規
格等に設定された標準空気圧を充填されたタイヤにおい
て、タイヤ最大幅の下部の部位からビ−ドコア上面の部
位までのカ−カスプライの範囲としている。そして、前
記タイヤ最大幅の下部の部位(図1上、100)とは、
タイヤ回転軸に直角方向の直線距離で測定した前記ホイ
−ルのフランジ部の頂点(101)から前記タイヤの最
大幅(102)までの距離のほぼ1/4を前記タイヤ最
大幅(102)からビ−ドコア方向に取った位置として
いる。Further, in the present invention, the bead portion of the carcass layer folded-back portion means a tire maximum width in a tire mounted on a wheel and filled with standard air pressure set to a standard or the like. The range of the carcass ply from the lower part to the upper part of the bead core. And the lower part of the tire maximum width (100 in FIG. 1) is
Approximately ¼ of the distance from the apex (101) of the flange portion of the wheel to the maximum width (102) of the tire measured with a straight line distance in the direction perpendicular to the tire rotation axis is approximately 1/4 of the maximum tire width (102). The position is taken in the direction of the bead core.
【0010】[0010]
【作用】本発明者等は、ポリエステルモノフィラメント
コ−ドをカ−カスプライコ−ドとして使用した通常構造
のタイヤを試作してタイヤへの負荷条件の過酷な室内ド
ラム試験及び10万Km以上の長距離実車走行試験を行
って、走行後のタイヤ各部位におけるカ−カスプライコ
−ドの残存強力を詳細に測定した結果より、カ−カスプ
ライ層折り返し部のビ−ド部分では走行前に対して走行
後のコ−ド引張強力は著しく低下(一部にコ−ド破断が
認められた)するが、その他の部位ではコ−ド引張強力
の低下率(走行前に対する走行後のコ−ド強力)は高々
10%以内であって殆どコ−ド強力が低下しないとの知
見を得た。更に、カ−カスプライ層折り返し部のビ−ド
部分のモノフィラメントコ−ドの破断故障部分を詳細に
観察した結果、該破断故障の程度はタイヤ接地時のタイ
ヤビ−ド部分の曲げ変形に基づく圧縮歪み量の大きさに
依存していることが判明した。換言すれば、カ−カスプ
ライ層折り返し部のビ−ド部分にかかる前記圧縮歪み量
を低減すればコ−ド破断に至るタイヤ寿命を伸ばすこと
ができるとの知見を得た。The present inventors prototyped a tire having a normal structure using a polyester monofilament cord as a carcass ply cord, and conducted an indoor drum test under severe tire load conditions and a long distance of 100,000 km or more. From the results of detailed measurements of the remaining strength of the carcass ply cord at each part of the tire after running by running the actual vehicle test, the bead portion of the folded portion of the carcass ply layer after running was compared to before running. The code tensile strength is remarkably reduced (cord rupture is observed in some areas), but the rate of decrease in code tensile strength (code strength after running compared to before running) is high in other areas. It was found that it was within 10% and the code strength was hardly reduced. Further, as a result of observing in detail the fracture failure portion of the monofilament code in the bead portion of the carcass ply layer folded-back portion, the degree of the fracture failure is the compressive strain based on the bending deformation of the tire bead portion when the tire touches the ground. It turned out to be dependent on the size of the quantity. In other words, it was found that if the amount of compressive strain applied to the bead portion of the carcass ply layer turnback portion is reduced, the tire life leading to code breakage can be extended.
【0011】上記の知見に基づいて発明者等は、前記圧
縮歪みを低減するビ−ド部の構造を検討して特許請求項
1に記載する構造を得た。即ち、カ−カス層(プライ)
折り返し部のビ−ド部分の形状が、タイヤのト−タル厚
さをAとしタイヤの外壁からカ−カス層折り返し部のコ
−ドまでの距離をBとする時、B/A>0.5を満足す
る様に形成されるものである。Based on the above findings, the inventors studied the structure of the bead portion for reducing the compressive strain and obtained the structure described in claim 1. That is, the carcass layer (ply)
When the shape of the bead portion of the folded portion is A and the total thickness of the tire is A, and the distance from the tire outer wall to the cord of the carcass layer folded portion is B, B / A> 0. It is formed so as to satisfy 5.
【0012】この様にビ−ド部の構造を設定すると、カ
−カスプライ層折り返し部のビ−ド部分は、ビ−ド部の
横断面において各位置の肉厚の中心位置(即ち、0.5
×Aの位置)を結ぶ線に相当する所謂中立軸線のタイヤ
軸方向内側に配置されることとなる。従って、タイヤが
内圧を充填されて走行することによってタイヤビ−ド部
分はこれをタイヤ軸方向の外側に倒す様な曲げ変形を繰
り返し受けて、ビ−ド部横断面の前記中立軸線のタイヤ
軸方向の外側部分には圧縮歪みが繰り返し発生するが、
前述の如く、本発明のビ−ド構造ではこの部分にカ−カ
スプライ層が配置されておらずこの圧縮歪みを被ること
がない。従って、従来構造のポリエステルモノフィラメ
ントコ−ドタイヤで致命的であったカ−カスプライ層折
り返し部のコ−ド疲労及びコ−ド破断が防止されタイヤ
の耐久性が格段に向上される。When the structure of the bead portion is set in this manner, the bead portion of the folded back portion of the carcass ply layer is located at the center position of the wall thickness at each position (that is, 0 .. 5
It is arranged on the inner side in the tire axial direction of the so-called neutral axis corresponding to the line connecting the positions (xA). Therefore, when the tire runs while being filled with the internal pressure, the tire bead portion is repeatedly subjected to bending deformation so as to incline it to the outside in the tire axial direction, and the tire axial direction of the neutral axis of the cross section of the bead portion. Compressive strain is repeatedly generated on the outer part of
As described above, in the bead structure of the present invention, the carcass ply layer is not arranged in this portion, so that it does not suffer from this compressive strain. Therefore, the cord fatigue and the code breakage at the folded portion of the carcass ply layer, which are fatal in the conventional polyester monofilament code tire, are prevented, and the durability of the tire is remarkably improved.
【0013】又、一般に高分子材料では材料がより高分
子であるほど耐疲労性が良いことが分子力学的に考えら
れるので、分子量の高低の目安となる固有粘度[η]の
値を変更したポリエステルモノフィラメントコ−ドをカ
−カスに用いたタイヤを数種類試作してタイヤ走行後の
カ−カスコ−ドの強力低下を調査した結果、前記の固有
粘度が0.75未満であるとカ−カスプライ層折り返し
部のビ−ド部分以外のカ−カスプライ層でも走行後のコ
−ド強力の低下が顕著に認められることが判明したの
で、本発明においてはカ−カスプライ層のコ−ドの固有
粘度を0.75以上としている。また、使用条件のバラ
ツキを考慮して、この値を0.85以上に設定すること
が好ましい。In general, in a polymer material, the higher the material is, the better the fatigue resistance is considered to be in terms of molecular mechanics. Therefore, the value of the intrinsic viscosity [η], which is a measure of the molecular weight, is changed. As a result of investigating a decrease in strength of the carcass cord after running the tire by prototyping several kinds of tires using a polyester monofilament cord as a carcass, it is found that the above-mentioned intrinsic viscosity is less than 0.75. Since it was found that the cord strength after running was remarkably reduced even in the carcass ply layer other than the bead portion of the layer turn-back portion, the intrinsic viscosity of the cord of the carcass ply layer was found in the present invention. Is set to 0.75 or more. In addition, it is preferable to set this value to 0.85 or more in consideration of variations in usage conditions.
【0014】又、ポリエステルモノフィラメントコ−ド
の織度(即ち、デニ−ル数)の選択については、100
0デニ−ル未満では、カ−カスプライ層が1プライでは
充填内圧に対する強度(安全率)不足となるためプライ
数の増加を要し、その結果タイヤ重量の増加ひいては転
がり抵抗の増加となる他、製造能率の低下とコストの上
昇を招き好ましくない。The selection of the weaving degree (that is, the number of denier) of the polyester monofilament cord is 100.
If it is less than 0 denier, the carcass ply layer is insufficient in strength (safety factor) against the filling internal pressure with 1 ply, so that an increase in the number of plies is required, resulting in an increase in tire weight and in turn an increase in rolling resistance. This is not preferable because it leads to a decrease in manufacturing efficiency and an increase in cost.
【0015】更に、本発明に係る空気入りラジアルタイ
ヤでは、従来汎用とされるマルチフィラメント撚りコ−
ドの空気入りラジアルタイヤに比較して極めて高モジュ
ラス及び低熱収縮の特性を有するために、従来のマルチ
フィラメント撚りコ−ドの空気入りラジアルタイヤと同
等の打ち込み数または同一のデニ−ル数にした場合は、
タイヤの剛性が大幅に向上して操縦安定性に優れしかも
カ−カスコ−ド配列の不均一に起因する内圧充填時のタ
イヤサイドの凹凸を小さく抑制するタイヤを得ることが
出来る。Further, in the pneumatic radial tire according to the present invention, a multifilament twisted cord which is conventionally used in general is used.
In order to have characteristics of extremely high modulus and low heat shrinkage as compared with the pneumatic radial tire of the conventional type, the same number of denier or the same number of denier as the pneumatic radial tire of the conventional multi-filament twisted cord was used. If
It is possible to obtain a tire in which the rigidity of the tire is significantly improved, the steering stability is excellent, and the unevenness on the tire side at the time of filling the internal pressure due to the nonuniform carcass arrangement is suppressed.
【0016】また一方、本発明に係る空気入りラジアル
タイヤにおいて、このタイヤのカ−カス剛性を従来のマ
ルチフィラメント撚りコ−ドの空気入りラジアルタイヤ
と略同等に設定することによって、カ−カスプライの打
ち込み数(単位幅当たりのコ−ド本数)の低減やコ−ド
自体のデニ−ル数(即ち、コ−ドの太さ)の減少が可能
となってタイヤ重量が減少し、タイヤの転がり抵抗の低
減従ってタイヤの燃費性能の向上を図ることが出来る。On the other hand, in the pneumatic radial tire according to the present invention, the carcass rigidity of this tire is set to be substantially the same as that of the conventional pneumatic radial tire of multifilament twist code, so that The number of driving (the number of cords per unit width) and the number of denier of the cord itself (that is, the thickness of the cord) can be reduced, the tire weight is reduced, and the rolling of the tire Therefore, the resistance can be reduced, and the fuel efficiency of the tire can be improved.
【0017】尚、若し、これと同等の打ち込み低減やデ
ニ−ル数の低減を従来のマルチフィラメント撚りコ−ド
の空気入りラジアルタイヤで実施しようとすると、タイ
ヤ剛性低下を補うために、フィラメント材としてポリエ
ステルより更に高モジュラスの別種類の高分子繊維材料
を用いることが必要となり、同時にタイヤの耐サイドカ
ット性(路面上の異物がタイヤサイド部を貫通しようと
するのを防止する能力)が低下する傾向が生ずることが
発明者等の別の実験によって確かめられており、タイヤ
の安全上の問題から実用化は非常に困難となる。Incidentally, if it is attempted to reduce the driving force and the number of deniers equivalent to these with a conventional radial radial tire having a multifilament twist cord, in order to make up for a decrease in tire rigidity, the filament is reduced. It is necessary to use another type of polymeric fiber material with a higher modulus than polyester as the material, and at the same time the side cut resistance of the tire (the ability to prevent foreign matter on the road surface from trying to penetrate the tire side part) It has been confirmed by another experiment by the inventors that the tendency to decrease is caused, and it is very difficult to put it into practical use due to safety problems of tires.
【0018】[0018]
【実施例】以下に本発明の実施例を説明する。タイヤサ
イズをラジアルタイヤ195/70R14としタイヤの
基本的構造を一層のカ−カスプライと2枚のスチ−ルベ
ルトとした実施例、比較例の各々についてそれぞれ数本
ずつのタイヤを試作して下記に説明する各種の試験を実
施した。Embodiments of the present invention will be described below. Several tires were manufactured as prototypes for each of the examples of the tire size of the radial tire 195 / 70R14, the basic structure of the tire was one layer of the carcass ply and the two steel belts, and the comparative example. Various tests were conducted.
【0019】表1にコ−ドの物性試験の結果を示す。こ
の試験結果に明らかの如く、本発明に係るポリエステル
モノフィラメントコ−ドでは、従来タイヤに使用されて
来たポリエステルマルチフィラメントコ−ドに比較し
て、コ−ド一本当たり負荷荷重が比較的大きな所謂中間
伸度(コ−ド一本当たり荷重6.75kg時の伸び)で
の伸びはあまり変わらないが、タイヤが実際に使用され
る際にタイヤコ−ドが受ける負荷荷重に相当する応力範
囲でのモジュラス即ち、初期モジュラスの値が大きく
(143%)、従って内圧充填時のタイヤの変形や操縦
安定性能に影響を及ぼすタイヤ剛性が高くなり、しかも
熱収縮率が極めて小さい。Table 1 shows the results of the physical property test of the cord. As is clear from the test results, the polyester monofilament cord according to the present invention has a relatively large load load per cord as compared with the polyester multifilament cord which has been conventionally used for tires. The elongation at the so-called intermediate elongation (elongation at a load of 6.75 kg per cord) does not change much, but in the stress range corresponding to the load applied to the tire code when the tire is actually used. The value of the initial modulus is large (143%), and therefore the tire rigidity which affects the deformation of the tire and the steering stability at the time of filling with internal pressure is high, and the heat shrinkage is extremely small.
【0020】[0020]
【表1】 [Table 1]
【0021】表2の実施例のタイヤ及び表3の各試験タ
イヤは、全て、カ−カスプライの材質として表1右欄に
示す物性を持つ3000デニ−ルの断面楕円形(短径
0.33mm、長径0.83mm)のポリエステルモノ
フィラメントコ−ドを使用し、一方表2の比較例のタイ
ヤは、カ−カスプライの材質として表1左欄に示す物性
を持つ1500デニ−ルのマルチヤ−ン集束体2本を下
撚り上撚りを各々長さ10cm当たり40回の撚り数で
より撚り合わせた(即ち、1500D/2本撚りの)ポ
リエステルマルチフィラメントコ−ドを使用している。The tires of the examples of Table 2 and the test tires of Table 3 are all 3,000 denier elliptical cross sections (minor diameter 0.33 mm) having the physical properties shown in the right column of Table 1 as the material of the carcass ply. , Long diameter 0.83 mm) polyester monofilament cord, while the tire of the comparative example in Table 2 is a 1500 denier multi-yarn bundle having the physical properties shown in the left column of Table 1 as the material of the carcass ply. A polyester multi-filament cord is used in which two bodies are twisted with the lower twist and the upper twist at a twist number of 40 times per 10 cm length (that is, 1500 D / 2-twist).
【0022】表2は、表1に示す物性でしかも固有粘度
[η]を0.83としたポリエステルモノフィラメント
コ−ドを用いたカ−カスプライコ−ドの打ち込みを変更
して、特に操縦安定性の向上を狙った本発明に係る実施
例1のタイヤと、特にタイヤの転がり抵抗を低減して燃
費特性の向上を狙った本発明に係る実施例2のタイヤと
を試作して、別に試作した従来のポリエステルマルチフ
ィラメントコ−ドをカ−カスプライに用いた比較例1の
タイヤと共にタイヤ性能試験を実施し比較したものであ
る。Table 2 shows the physical properties shown in Table 1 and changes in the driving of the carcass ply cord using a polyester monofilament cord having an intrinsic viscosity [η] of 0.83 to improve the steering stability. The tire of Example 1 according to the present invention aiming at improvement and the tire of Example 2 according to the present invention aiming at improvement of fuel consumption characteristics by reducing rolling resistance of the tire were prototyped and separately prototyped conventionally. A tire performance test was carried out and compared with the tire of Comparative Example 1 in which the polyester multifilament cord of No. 1 was used for the carcass ply.
【0023】なお、実施例1及び実施例2のビ−ド部1
の構造は、図1に示す如く、カ−カス層折り返し部3
は、ビ−ドコア2の回りに巻回して折り返されビ−ドコ
アの上面付近でカ−カス層の本体側に接近し以後カ−カ
ス層の本体側と並列してタイヤ径方向上方に延設されて
いる。また、該折り返し部3の端末4は、前記タイヤ最
大幅の下部の部位の下方において止められている。そし
て、前記折り返し部3のビ−ド部の形状は、タイヤのト
−タル厚さをAとしタイヤの外壁5からカ−カス層折り
返し部のコ−ド6までの距離をBとする時、B/Aの値
がそれぞれ0.55及び0.75を満足する様に形成さ
れている。実施例2の場合は、実施例1に比べ打ち込み
を減少した分だけサイド部の剛性が低いのでB/Aの値
を大きく設定している。なお、上記のB/Aの値を変更
するには、前記カ−カス層折り返し部3を挟む左右の補
強ゴム7、7’の断面積の比率及び形状を変更して行わ
れる。The bead portion 1 of the first and second embodiments
As shown in FIG. 1, the structure of FIG.
Is wound around the bead core 2 and folded back to approach the body side of the carcass layer in the vicinity of the upper surface of the bead core and thereafter extend in the tire radial direction in parallel with the body side of the carcass layer. Has been done. Further, the terminal 4 of the folded-back portion 3 is stopped below the lower portion of the tire maximum width. When the total thickness of the tire is A and the distance from the outer wall 5 of the tire to the cord 6 of the carcass layer folding portion is B, the shape of the bead portion of the folding portion 3 is B, The B / A values are formed to satisfy 0.55 and 0.75, respectively. In the case of the second embodiment, the rigidity of the side portion is lower than that of the first embodiment by the amount of reduced driving, so the value of B / A is set to a large value. The value of B / A is changed by changing the cross-sectional area ratios and shapes of the left and right reinforcing rubbers 7 and 7 ′ sandwiching the carcass layer turn-back portion 3.
【0024】表2から明らかなように、打ち込みの多い
実施例1のタイヤは、耐サイドカット性を表すサイドプ
ランジャ−値が非常に大きくなってタイヤサイド部の剛
性が極めて高く、操縦安定性能に優れている。一方、打
ち込み数を減らしてタイヤサイド部の剛性(即ち、サイ
ドプランジャ−値)が比較例タイヤ並となっている実施
例2のタイヤでは、操縦安定性能が比較例タイヤ(即
ち、従来タイヤ)並に維持されながらも転がり抵抗が低
減され燃費性能の向上が得られている。また、内圧充填
時のタイヤサイド部表面の凹凸も実施例のタイヤでは殆
ど感知し得ない程度のものに抑えられている。As is clear from Table 2, in the tire of Example 1 with a large amount of driving, the side plunger value indicating the side cut resistance is very large, the rigidity of the tire side portion is extremely high, and the steering stability performance is improved. Are better. On the other hand, in the tire of Example 2 in which the number of driving is reduced and the rigidity of the tire side portion (that is, the side plunger value) is comparable to that of the comparative example tire, the steering stability performance is comparable to that of the comparative example tire (that is, the conventional tire). The rolling resistance is reduced and the fuel economy performance is improved while being maintained at. Further, the unevenness of the tire side surface at the time of filling with the internal pressure is suppressed to a level that is almost undetectable by the tires of the examples.
【0025】[0025]
【表2】 [Table 2]
【0026】次に、表3に示される如く、カ−カスプラ
イコ−ドとして前記表1に記した本発明に係るポリエス
テルモノフィラメントコ−ドを用いて、カ−カス層折り
返し部のビ−ド部分の形状を規定する前記B/Aの値及
びカ−カスプライコ−ドの固有粘度の値の影響度を確認
するために、ビ−ド耐久ドラム試験を実施した。また同
時に、前述した実施例1及び実施例2のタイヤのビ−ド
部の耐久性についてもその耐久性を確認した。尚、従来
のタイヤ即ち前記表2の比較例のタイヤのビ−ド部の耐
久性は、2万km走行し故障なしのレベルであって、過
去の市場実績から2万km走行し故障なしのレベルを合
格レベルとしている。Next, as shown in Table 3, the polyester monofilament cord according to the present invention described in Table 1 was used as the carcass ply code, and the bead portion of the folded portion of the carcass layer was used. A bead endurance drum test was conducted to confirm the degree of influence of the B / A value which defines the shape and the intrinsic viscosity value of the carcass plycode. At the same time, the durability of the bead portions of the tires of Examples 1 and 2 described above was also confirmed. The durability of the bead portion of the conventional tire, that is, the tire of the comparative example shown in Table 2 above, is a level of no failure after running 20,000 km, which is 20,000 km after running in the past market. The level is regarded as a passing level.
【0027】表3に示される結果から、カ−カス層折り
返し部のビ−ド部分の形状を規定する前記B/Aの値が
0.5以下では十分な耐久性が期待できず、また固有粘
度が0.70と0.83の中間の値付近(即ち、約0.
75)未満では耐久性が不充分と判断することが出来
る。また、前記表2で検討した実施例1及び2のタイヤ
については、共に2万kmを完走して合格レベルの耐久
性を具えていることが確認された。From the results shown in Table 3, when the value of B / A which defines the shape of the bead portion of the carcass layer folded-back portion is 0.5 or less, sufficient durability cannot be expected, and the peculiarity is unique. Viscosity is near an intermediate value between 0.70 and 0.83 (that is, about 0.
If it is less than 75), it can be judged that the durability is insufficient. In addition, it was confirmed that the tires of Examples 1 and 2 examined in Table 2 both completed the 20,000 km and had a pass level durability.
【0028】[0028]
【表3】 [Table 3]
【0029】尚、上記実施例ではタイヤの基本構造とし
てカ−カスプライを一層とし、ベルトをスチ−ルベルト
2層としたが、本発明は、これに限定されることなく、
これらの構造を必要に応じて変更アレンジしたものにも
適用出来る。Although the carcass ply is one layer and the belt is two layers of the steel belt as the basic structure of the tire in the above embodiment, the present invention is not limited to this.
It is also applicable to those structures that are modified and arranged as necessary.
【0030】[0030]
【発明の効果】本発明の空気入りラジアルタイヤによっ
て、ポリエステルモノフィラメントコ−ドをカ−カスプ
ライに適用したラジアルタイヤの走行疲労に対する耐久
性が大幅に改良され、操縦安定性の向上やタイヤ重量の
軽量化による転がり抵抗の低減などタイヤ性能が著しく
向上でき、更に内圧充填時のタイヤサイドの凹凸が抑制
され良好な外観を得ることが出来る。The pneumatic radial tire of the present invention greatly improves the durability against running fatigue of a radial tire in which a polyester monofilament cord is applied to a carcass ply, improves steering stability, and reduces the weight of the tire. As a result, the tire performance can be remarkably improved by reducing the rolling resistance due to the increase in pressure, and further, the unevenness on the tire side at the time of filling with internal pressure is suppressed, and a good appearance can be obtained.
【図面の簡単な説明】[Brief description of drawings]
【図1】実施例のビ−ド部の構造を示すタイヤビ−ド部
の横断面図である。FIG. 1 is a cross-sectional view of a tire bead portion showing a structure of a bead portion of an embodiment.
1 ビ−ド部 2 ビ−ドコア 3 カ−カス層折り返し部 4 カ−カス層折り返し部の端末 5 タイヤの外壁 6 カ−カス層折り返し部のコ−ド 7、7’ 補強ゴム 100 タイヤ最大幅の下部の部位 101 フランジ部の頂点 102 タイヤの最大幅 DESCRIPTION OF SYMBOLS 1 bead part 2 bead core 3 carcass layer folded part 4 end of carcass layer folded part 5 tire outer wall 6 cord of carcass layer folded part 7, 7'reinforcement rubber 100 tire maximum width Lower part 101 Top of flange 102 Maximum tire width
Claims (2)
ング状ビ−ドコアと、両端が該ビ−ドコアに巻回されて
折り返され中央部が円環体状に形成されたカ−カス層
と、該カ−カス層中央部の頭頂部のタイヤ径方向外側に
複数枚積層された帯状のベルト層とを主補強構造とし
て、前記帯状のベルト層のタイヤ径方向外側にリング状
のトレッドゴムが配置され、該トレッドゴムの両側に前
記カ−カス層を覆って左右一対のサイドゴムが配置さ
れ、しかも、前記カ−カス層が複数のポリエステルモノ
フィラメントコ−ドがタイヤの赤道面に対してほぼ直角
方向に並列されて被覆ゴム中に埋設されて成る空気入り
ラジアルタイヤであって、タイヤの回転軸方向の内側か
ら外側に向かってビ−ドコア回りに巻回し折り返された
カ−カス層折り返し部のビ−ド部分の形状が、タイヤの
ト−タル厚さをAとしタイヤの外壁からカ−カス層折り
返し部のコ−ドまでの距離をBとする時、B/A>0.
5を満足する様に形成され、且つ前記カ−カス層が固有
粘度が0.75以上のポリエステルモノフィラメントコ
−ドから成ることを特徴とする空気入りラジアルタイ
ヤ。1. A pair of ring-shaped bead cores arranged at right and left intervals, and a carcass having both ends wound around the bead core and folded back to form a central portion in an annular shape. Layer and a plurality of belt-shaped belt layers laminated on the tire radial direction outer side of the top of the center portion of the carcass layer as a main reinforcing structure, and the ring-shaped tread of the belt shaped belt layer on the tire radial direction outer side. A rubber is disposed, and a pair of left and right side rubbers are disposed so as to cover the carcass layer on both sides of the tread rubber, and the carcass layer has a plurality of polyester monofilament cords with respect to the equatorial plane of the tire. A pneumatic radial tire which is juxtaposed in a substantially perpendicular direction and embedded in a coated rubber, wherein a carcass layer is folded back around a bead core from an inner side to an outer side in a rotation axis direction of the tire. Part of When the total thickness of the tire is A and the distance from the outer wall of the tire to the cord of the carcass layer folding portion is B, the shape of the cord portion is B / A> 0.
5. A pneumatic radial tire characterized in that the carcass layer is formed of a polyester monofilament cord having an intrinsic viscosity of 0.75 or more.
ノフィラメントコ−ドの繊度が1000デニ−ル以上で
ある特許請求項1に記載の空気入りラジアルタイヤ。2. The pneumatic radial tire according to claim 1, wherein the polyester monofilament cord constituting the carcass has a fineness of 1000 denier or more.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP6250987A JPH08113017A (en) | 1994-10-17 | 1994-10-17 | Pneumatic radial tire |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP6250987A JPH08113017A (en) | 1994-10-17 | 1994-10-17 | Pneumatic radial tire |
Publications (1)
Publication Number | Publication Date |
---|---|
JPH08113017A true JPH08113017A (en) | 1996-05-07 |
Family
ID=17215988
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
JP6250987A Pending JPH08113017A (en) | 1994-10-17 | 1994-10-17 | Pneumatic radial tire |
Country Status (1)
Country | Link |
---|---|
JP (1) | JPH08113017A (en) |
-
1994
- 1994-10-17 JP JP6250987A patent/JPH08113017A/en active Pending
Similar Documents
Publication | Publication Date | Title |
---|---|---|
US7484545B2 (en) | Radial tire for aircraft with specified merged cords | |
KR100532177B1 (en) | Reinforcement fabrics for elastic material products and elastic material products including this reinforcement fabric | |
US7063116B2 (en) | Pneumatic tire with monofilament metallic belt cords | |
US7316254B2 (en) | Pneumatic tire | |
US20090090447A1 (en) | Tire cord reinforcement | |
EP2261059B1 (en) | Pneumatic tire with an overlay reinforcement | |
CN104228465B (en) | Mixing cord for pneumatic tire | |
EP2604448B1 (en) | Composite cord and overlay ply for a pneumatic tire | |
EP2380756A1 (en) | Carcass ply for a pneumatic tire | |
US20110259501A1 (en) | Hybrid cord in a belt ply for a pneumatic tire | |
JP2009091713A (en) | Tyre code reinforcement | |
US6926053B2 (en) | Pneumatic tire variable elasticity modules metallic band cord | |
US20100065178A1 (en) | Carcass ply for a pneumatic tire | |
EP2806057A2 (en) | Hybrid cord and tire comprising a hybrid cord | |
KR920004694B1 (en) | Tire construction utilizing low-twist body ply yarn with low turn-up ends | |
US20120067487A1 (en) | Tires with high strength reinforcement | |
EP3950385A1 (en) | Tire with a shearband structure | |
JP4153127B2 (en) | Pneumatic tire | |
JP5305389B2 (en) | Pneumatic radial tire | |
EP2380755B1 (en) | Overlay ply covering the belt ply for a pneumatic tire | |
JPH08113017A (en) | Pneumatic radial tire | |
JP3532969B2 (en) | Pneumatic radial tire | |
US20120067488A1 (en) | Tires with high strength reinforcement | |
JP2001039108A (en) | Pneumatic radial tire | |
JP6092058B2 (en) | Pneumatic radial tire |