JP2004189156A

JP2004189156A - Pneumatic tire and manufacturing method thereof

Info

Publication number: JP2004189156A
Application number: JP2002361233A
Authority: JP
Inventors: Yuji Sato; 有二佐藤; Toshihiko Take; 武　　敏彦
Original assignee: Yokohama Rubber Co Ltd
Current assignee: Yokohama Rubber Co Ltd
Priority date: 2002-12-12
Filing date: 2002-12-12
Publication date: 2004-07-08
Anticipated expiration: 2022-12-12
Also published as: JP4060173B2

Abstract

<P>PROBLEM TO BE SOLVED: To provide a pneumatic tire and a manufacturing method thereof to improve uniformity. <P>SOLUTION: In a belt cover, a strip material is wound at a constant pitch on an edge part forming both side ends of a belt. On a central part, the strip material is wound at a pitch of the same length as the width of the strip material. Also, the strip material is wound so that a winding starting position and a winding ending position of the strip material on the edge part, and a pitch changing position on the boundary between the edge part and the central part can be settled within a prescribed range in a circumferential direction. The strip material is wound in one direction, i.e. from the left to the right, in a width direction of the belt. As described above, when the strip material is wound and the belt cover is formed, strip material component of an RFV waveform can be reduced. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

【０００１】
【発明の属する技術分野】
この発明は、空気入りタイヤ、および空気入りタイヤの製造方法に関し、更に詳しくは、タイヤのユニフォーミティの向上に資するベルトカバーを有する空気入りタイヤ、および空気入りタイヤの製造方法に関する。
【０００２】
【従来の技術】
図１７は、従来の空気入りタイヤを示す説明図である。ここでは、典型的なラジアルタイヤについて説明する。タイヤ１０１は、カーカス１０２に複数のスチール製のベルト１０３、１０４、がタイヤの半径方向に重ねられて構成される。また、タイヤは、高速特性を高めるためにベルト１０３、１０４とトレッド１０６の間にベルトカバー１０５が配置される。
【０００３】
このベルトカバー１０５は、シート状のものを周上一カ所でつなぎ合わせると、その部分が不連続点となりユニフォーミティ（以下ＵＦと略する。）、特にＵＦ試験におけるＲＦＶ（Radial Force Variation半径方向力変動）、ＲＲＯ（Radial Run Out半径方向振れ）に悪影響を及ぼすことが知られている。このため、ベルトカバー１０５は、有機繊維コードをゴムで覆った細い帯材（ストリップ材）を螺旋に巻き付けることにより形成されているのが一般的である（たとえば、特許文献１、２参照。）。
【０００４】
図１８は、従来のベルトカバーの例を示す外観図である。この図は、３６０度分のベルトカバーを平面に展開したものである。同図下部にはベルトカバーを半径方向で切ったときの断面図を示した。同図に示したように、従来のベルトカバーは、ベルトのエッジから所定寸法だけ内側に入った所を開始位置として帯材１０７を巻き始め、紙面右から左に巻いた後、折り返して左から右、さらに折り返して右から左と螺旋状に巻く。そして、上記開始位置とは反対側のベルトのエッジから所定寸法内側で巻き終わる。
【０００５】
上記のように帯材１０７を巻くと、ベルトのエッジ部に帯材１０７が２重に巻かれることになり、ベルトのエッジ部を頑丈に補強できると共に、中心部も１重の帯材１０７で補強できる。なお、この巻き方はタイヤの制限速度規格（ＪＩＳＤ４２０１、Ｄ４２０２）でいうところのＶ規格（最大２４０ｋｍ／ｈまで）やＷ、Ｙ規格（２４０ｋｍ／ｈ以上）で用いられることが多い。
【０００６】
上記の他にも、Ｈ規格（最大２１０ｋｍ／ｈまで）等では、ベルトのエッジ部分のみ帯材１０７を巻く２重エッジカバー形式や、エッジ部から中心部にかけて１重の帯材１０７で巻くフルカバー形式もある。これらのベルトカバーは、タイヤの高速性能を左右する因子の一つであるベルトの剛性を高めるために、適当な形式が選択・採用される。
【０００７】
図１９は、従来のベルトカバーの例を示す外観図である。同図は、図１８と同様に、３６０度分のベルトカバーを平面に展開したものであり、下部にはベルトカバーを半径方向で切ったときの断面図を示した。図中、上に示したのが、２重フルカバー＋エッジカバー形式で、図１８のフルカバー＋エッジカバー形式の下層に帯材を１重に巻いたものである。これらは、ベルト剛性のさらなる向上を目的として用いられる。
【０００８】
具体的な巻き方は、左右どちらか一方からほぼ全面に対して帯材を１重に巻き、次に既述したフルカバー＋エッジカバー形式のように、ベルトのエッジから所定寸法内側を開始位置として帯材を巻き始め、紙面右から左に巻いた後、折り返して左から右、さらに折り返して右から左と螺旋状に巻く。そして、上記開始位置とは反対側のベルトのエッジから所定寸法内側で巻き終わる。
【０００９】
さらに、同図下に示したのがエッジ部を３重にすると共に中央部を１重に巻く形式で、２重のエッジカバー形式の上層にフルカバー形式の１重帯材を巻いたものである。具体的な巻き方は、まず左右のベルトエッジ部に対して内側から巻き始め、外側で折り返し、再び内側に戻し巻く。その上から、左右どちらか一方からほぼ全面に対して帯材を１重に巻く。
【００１０】
【特許文献１】
特開平４−３５５１２１号公報（第２〜４頁、第２、４図）
【特許文献２】
実開昭６２−１７８２０１号公報（第６頁、第４、５図）
【００１１】
【発明が解決しようとする課題】
しかしながら、上記従来技術に係る空気入りタイヤのベルトカバーは、剛性及び高速特性という観点では向上し得るが、その一方で、タイヤの振動特性に影響するＵＦという観点から見た場合、帯材を螺旋に巻き、折り返すことから、ベルトカバー自体の周上の均一性を常に確保することは困難であるという問題点があった。具体的には、ベルトカバー自体の総幅、２重以上の重ね巻き部分の幅、タイヤ赤道線から重ね巻き部分までの距離の左右和、又、ベルトエッジのみをカバーする構造の場合に、タイヤ赤道線からカバー内側までの距離の左右和に周上バラツキが発生する。ＵＦに欠けているタイヤは、特に高速回転したときの車輌の振動や騒音に悪影響を及ぼしてしまう。
【００１２】
そこで、この発明は、上記に鑑みてなされたものであって、タイヤのユニフォーミティの向上に資するベルトカバーを有する空気入りタイヤ、および空気入りタイヤの製造方法を提供することを目的とする。
【００１３】
【課題を解決するための手段】
上述の目的を達成するために、請求項１に係る空気入りタイヤは、カーカスの外側に設けられるベルトの半径方向外側に当該ベルトの少なくとも両エッジ部を覆うように、それぞれのエッジ部分で帯材の巻き付けによるベルトカバーを有する空気入りタイヤにおいて、前記ベルトカバーは、前記帯材が一定ピッチで重ね巻かれると共に、双方の前記帯材の巻き始め位置と巻き終わり位置がすべて周方向における所定範囲に収まるように巻かれ、かつ、双方の前記帯材が、ベルトの幅方向における同一方向に巻かれるようにしたものである。
【００１４】
ベルトカバーを形成する帯材の巻き付けピッチを一定にしてベルトエッジ部に重ね巻き部分、すなわち複数回の重ね巻き部分を形成すると、当該複数回の重ね巻き部分の幅が周上で均一になる。また、帯材の左右の巻き始め、巻き終わり位置を周方向における所定範囲に収め、かつ、ベルトの幅方向の一方向（左右どちらか一方から他方に向かう方向）に帯材を巻き付けると、エッジ部における帯材の最内側とタイヤ赤道面との距離及び複数回の重ね巻き部分の最内側と赤道面からの距離の左右和が周上で均一になる。
【００１５】
また、請求項２に係る空気入りタイヤは、前記空気入りタイヤにおいて、前記一定ピッチは、前記帯材の幅の１／２が重ね合わさるピッチであるようにしたものである。
【００１６】
また、請求項３に係る空気入りタイヤは、前記空気入りタイヤにおいて、双方の前記帯材の最内側に、さらに環状の帯材一巻きを加えたものである。
【００１７】
また、請求項４に係る空気入りタイヤは、カーカスの外側に設けられるベルトの半径方向外側であって、当該ベルトの少なくとも両エッジ部を覆う位置で帯材の巻き付けによる２重以上の部分が形成され、中央部には前記帯材の巻き付けによる１重部分が形成されるベルトカバーを有する空気入りタイヤにおいて、前記２重以上の部分は、前記帯材が一定ピッチで重ね巻かれ、前記１重部分では、前記帯材の幅と同一長さのピッチで前記帯材が巻かれ、かつ、前記２重以上の部分における前記帯材の巻き始め位置と巻き終わり位置、および前記２重以上の部分と前記１重部分との境界でのピッチ変更位置がすべて周方向における所定範囲内に収まるように巻かれ、かつ、前記帯材が、前記ベルトの幅方向において一方向に巻かれるようにしたものである。
【００１８】
また、請求項５に係る空気入りタイヤは、前記空気入りタイヤにおいて、前記一定ピッチは、前記帯材の幅の１／２が重ね合わさるピッチであるようにしたものである。
【００１９】
また、請求項６に係る空気入りタイヤは、請求項１乃至５に係る空気入りタイヤの前記ベルトカバーの下層、または上層として、１重に巻かれた帯材が重ねられるものである。
【００２０】
この発明では、請求項１乃至５に係る空気入りタイヤにフルカバー形式の１重の帯材を組み合わせたものである。したがって、全体としては、３重以上の部分と１重部分、または３重以上の部分と２重部分を有するベルトカバーが形成され、ＵＦを向上させつつベルトを強固に補強する。
【００２１】
また、請求項７に係る空気入りタイヤの製造方法は、カーカスの外側に設けられるベルトの半径方向外側に当該ベルトの少なくとも両エッジ部を覆うように、それぞれのエッジ部分で帯材を巻き付けてベルトカバーを形成する空気入りタイヤの製造方法において、前記ベルトカバーは、前記帯材を一定ピッチで重ね巻くと共に、双方の前記帯材の巻き始め位置と巻き終わり位置がすべて周方向における所定範囲に収まるように巻き、かつ、双方の前記帯材を、前記ベルトの幅方向における同一方向に巻くようにしたものである。
【００２２】
ベルトカバーを形成する帯材の巻き付けピッチを一定にしてベルトエッジ部に重ね巻き部分、すなわち２重巻き以上の部分を形成すると、当該２重巻き以上の部分の幅が周上で均一になる。また、帯材の左右の巻き始め、巻き終わり位置、およびピッチ変更位置をすべて周方向における所定範囲に収め、かつ、ベルトの幅方向の一方向（左右どちらか一方から他方に向かう方向）に帯材を巻き付けると、エッジ部における帯材の最内側とタイヤ赤道面との距離及び２重巻き以上の部分の最内側と赤道面からの距離の左右和が周上で均一になる。
【００２３】
また、請求項８に係る空気入りタイヤの製造方法は、前記空気入りタイヤの製造方法において、前記一定ピッチは、前記帯材の幅の１／２が重ね合わさるピッチであるようにしたものである。
【００２４】
また、請求項９に係る空気入りタイヤの製造方法は、前記空気入りタイヤの製造方法において、双方の前記帯材の最内側に、さらに環状の帯材一巻きを加えるようにしたものである。
【００２５】
また、請求項１０に係る空気入りタイヤの製造方法は、カーカスの外側に設けられるベルトの半径方向外側であって、当該ベルトの少なくとも両エッジ部を覆う位置で帯材の巻き付けによる２重以上の部分を形成し、中央部には前記帯材の巻き付けによる１重部分を形成するベルトカバーを有する空気入りタイヤの製造方法において、前記２重以上の部分は、前記帯材を一定ピッチで重ね巻き、前記１重部分では、前記帯材の幅と同一長さのピッチで前記帯材を巻き、かつ、前記エッジ部の前記帯材の巻き始め位置と巻き終わり位置、および前記一重部分と前記２重以上の部分との境界でのピッチ変更位置がすべて周方向における所定範囲内に収まるように巻き、かつ、前記帯材を、前記ベルトの幅方向において一方向に巻くようにしたものである。
【００２６】
また、請求項１１に係る空気入りタイヤの製造方法は、前記空気入りタイヤの製造方法において、前記一定ピッチは、前記帯材の幅の１／２が重ね合わさるピッチとしたものである。
【００２７】
また、請求項１２に係る空気入りタイヤの製造方法は、空気入りタイヤを半径方向から見たときにタイヤ赤道面を境として左側に巻かれる帯材の幅合計と、右側に巻かれる帯材の幅合計との左右和を０にすると共に、タイヤ赤道面を境として左側に帯材が２重以上に巻かれる幅合計と、右側に２重以上に巻かれる幅合計との左右和を０にし、かつ、帯材が２重以上となる部分の最内側に対するタイヤ赤道面からの距離の左右和を０にして、ベルトカバーを形成するようにしたものである。
【００２８】
ベルトカバーは、帯材を螺旋状に巻いて形成するので、帯材が２重以上となる部分の最内側に対するタイヤ赤道面からの距離は、周上３６０度にわたって増減する。この発明では、そのように周上で増減する赤道面からの距離を左右相殺させることにより、帯材のアンバランスを解消させる。これにより、ＵＦの向上に資する空気タイヤを製造することができる。
【００２９】
また、請求項１３に係る空気入りタイヤの製造方法は、請求項７乃至１２に係る空気入りタイヤの製造方法に係る空気入りタイヤの前記ベルトカバーの下層、または上層として、１重に巻かれた帯材を重ねるようにしたものである。
【００３０】
【発明の実施の形態】
以下、この発明につき図面を参照しつつ詳細に説明する。なお、この実施の形態によりこの発明が限定されるものではない。また、この実施の形態の構成要素には、当業者が置換可能かつ容易なもの、或いは実質的に同一のものを含む。
【００３１】
（実施の形態１）
図１は、この発明の実施の形態１に係る空気入りタイヤのベルトカバーを示した説明図である。この図の上図は、３６０度分のベルトカバーを平面に展開したものである。上図下部にはベルトカバーを半径方向で切ったときの断面図を示した。下図は、上図の角度に対応したタイヤ特性を示したグラフ図である。縦軸は、周上の角度、横軸は左からそれぞれ総幅、２重部分幅、タイヤ赤道面から２重部分内側までの距離の左右和（以下、２重部分内側アパートと称する）、および帯材成分ＲＦＶ波形である。
【００３２】
同図上に示すように、このベルトカバーは、ベルト（図示省略）の両側端であるエッジ部でそれを覆うように前記帯材が一定ピッチで重ね巻かれる。ここでは、当該一定ピッチを帯材の幅の１／２が重なるピッチにしている。中央部では、帯材の幅と同一長さのピッチで帯材が巻かれる。つまり、エッジ部には帯材の２重巻き部分、中央部には１重巻き部分が形成される。また、エッジ部の帯材の巻き始め位置と巻き終わり位置、およびエッジ部と中央部との境界でのピッチ変更位置がすべて周方向における同一位置となるように帯材が巻かれる。そして、帯材は、さらにベルトの幅方向において一方向、ここでは左から右に巻かれる。
【００３３】
上記のように帯材を巻いてベルトカバーを形成すると、同図下の総幅および２重部分幅に示した通り、総幅、および２重部分の幅における変動の左右和が周上一定になる。なお、当該グラフ図では、左右のエッジ部それぞれの総幅、２重部分幅を点線で示しており、実線がその左右の和である。また、帯材の巻き始め位置、巻き終わり位置、およびピッチ変更位置を周方向における同一位置に配置し、かつ、ベルトの幅方向の一方向（ここでは左から右）に帯材を巻き付けると、２重部分内側アパートの左右和が周上３６０度を通して一定になる。
【００３４】
そして、最終的にＵＦのうち、ＲＦＶ波形の帯材成分は、１３Ｎと後述する他の形式のものに比べて低く抑えることができた。なお、帯材成分ＲＦＶ波形は、所定の条件で製造した空気入りタイヤを複数用意して、それぞれＲＦＶを測定し、帯材成分の影響のみを抽出したものである。このように、帯材の不連続点である帯材巻き始め位置と巻き終わり位置をすべて周方向における同一位置となるように帯材を巻くことは、ＲＦＶ波形のピークを招くということでこれまで避けられてきたものである。
【００３５】
この発明では、帯材の巻き方における他の条件と相まって、ＲＦＶを低く抑えることができた点に特徴がある。つぎに、発明者の創意と工夫によりこの発明に至るまでの経過を説明する。これにより、この発明の優れた着目点およびその効果が理解可能となる。
【００３６】
図２は、帯材の幅と同一ピッチで重ね巻きしたときのベルトカバーを示す説明図である。この図の上図は、３６０度分のベルトカバーを平面に展開したものである。上図下部にはベルトカバーを半径方向で切ったときの断面図を示した。下図は、上図の角度に対応したタイヤ特性を示したグラフ図である。縦軸は、周上の角度、横軸は左からそれぞれ総幅、２重部分幅、２重部分内側アパート、および帯材成分ＲＦＶ波形である。以後同様な図を用いて説明する。
【００３７】
同図に示すように、このベルトカバーは、帯材をその幅と同一ピッチ（以後１／１ピッチと称する。）でエッジ部を重ね巻きする。また、帯材の巻き始め位置および巻き終わり位置も周上の異なる位置にし、巻き始めから左に巻き、折り返した後右に巻き、再度折り返して左に巻く。このようにすると、同図下のグラフ図に示したように、２重部分幅、２重部分内側アパートとも３６０度を通しての左右の和が大きく乱れたものになる。その結果、帯材成分ＲＦＶ波形も大きくなり、最大２６Ｎと大きな値になった。
【００３８】
図３は、図２の帯材の巻き始め位置と巻き終わり位置を周上同一位置にしたときベルトカバーを示す説明図である。なお、帯材の総巻き数を１／２巻き増やして整数巻きとしたので、ベルトカバーの右端の形状は帯材１／２巻き分だけ異なる。このように帯材の巻き始め位置と巻き終わり位置を周上同一位置にすると、２重部分内側アパートの左右和こそ３６０度を通して一定になるものの、総幅、２重部分幅が大きく乱れる。その結果、帯材成分ＲＦＶ波形も２１Ｎと小さくすることができなかった。
【００３９】
図４は、図１の２重部分を帯材の１／２ピッチの重ね巻きで実現したときのベルトカバーを示す説明図である。なお、帯材の総巻き数は非整数巻きとした。このように帯材を幅方向において一方向で、重ね巻いても、巻き始め位置と巻き終わり位置が周上同一位置でないので、総幅、２重部分幅、および２重部分内側アパートが大きく乱れる。その結果、帯材成分ＲＦＶ波形も２８Ｎと小さくすることができなかった。なお、帯材を整数巻きにしても同様な結果となる。
【００４０】
図５は、図４のベルトカバーを帯材のセンター振り分けで実現したときのベルトカバーを示す説明図である。このように帯材をセンター振り分けにすると３６０度を通して総幅、２重部分幅、および２重部分内側アパートが大きく乱れる。その結果、帯材成分ＲＦＶ波形も１８Ｎと小さくすることができなかった。なお、このＲＦＶを求めるＵＦ試験では、タイヤサイズが異なったため、既述したベルトカバーと厳密には同列に論じることができないが、総幅等がいずれも大きく乱れていることから結果を推測できる。
【００４１】
以上説明したように、この発明の実施の形態１に係る空気入りタイヤによれば、帯材を用いてベルトエッジ部に複数に重なったベルトカバーを形成するときに発生する複数の重ね巻き部分幅、複数の重ね巻き部分内側アパートの左右和の周上バラツキを常に一定にすることができる。その結果、ベルトカバーのＵＦ、特にＲＦＶ、ＲＲＯへの影響を極めて小さくすることが出来ることがわかった。これにより、タイヤの高速特性を向上させることができる。なお、この発明における帯材のエッジ部の巻き付けピッチは、生産性や厚みの不均一を考慮すれば、帯材の幅の１／２、１／３、１／４、１／５、１／６ピッチ程度が望ましい。
【００４２】
また、この発明では、上記の様なベルトカバーの周上バラツキを０にする為に、巻き始め位置と巻き終わり位置、およびピッチ変更位置が周上同一位置であることが最も望ましいが、厳密に同一でなければ直ちに効果を失うものではない。つまり、巻き始め位置と巻き終わり位置は、所定範囲、具体的にはタイヤ中心角３０度以内程度であればある程度の効果は得られる。理想的にはタイヤ中心角１０度以内に収まることが望ましい。また、この発明は、ラジアルタイヤのみならず、ベルトを有するバイアスタイヤにも適用可能である。
【００４３】
（実施の形態２）
図６は、この発明の実施の形態２に係る空気入りタイヤのベルトカバーを示した説明図である。なお、同図は、図１〜５と異なり、下部のグラフ図は後述する内側アパート、２重部分幅、２重部分内側アパートの順に示した。このベルトカバーは、ベルト（図示省略）の両側端であるエッジ部で帯材が一定ピッチで重ね巻かれると共に、双方の帯材の巻き始め位置と巻き終わり位置がすべて周方向における同一位置となるように巻かれる。なお、ここでは、上記一定ピッチを１／２ピッチとした。また、双方の帯材が、ベルトの幅方向における同一方向、ここでは右から左に巻かれることをこの発明は特徴とする。
【００４４】
ベルトカバーを形成する帯材の巻き付けピッチを一定にしてベルトエッジ部に重ね巻き部分、すなわち２重巻き以上の部分を形成すると、当該２重巻き以上の部分の幅における左右和が周上３６０度を通して一定になる。また、帯材の左右の巻き始め位置、巻き終わり位置を周方向における同一位置に配置し、かつ、ベルトの幅方向の一方向に帯材を巻き付けると、双方のエッジ部における帯材の最内側とタイヤ赤道面からの距離、すなわち内側アパート、及び２重部分内側アパートの左右和が周上３６０度を通して一定になる。これにより、ＵＦに対して悪影響を及ぼす要因を無くすことができる。
【００４５】
このように、この実施の形態２に係るベルトカバーは、両エッジ部の帯材の巻き始め位置および巻き終わり位置を同一位置となるように帯材を巻く。このことは、実施の形態１と同様にＲＦＶ波形のピークを招くということでこれまで避けられてきたものである。ここで、実施の形態１と同様に、発明者の創意と工夫によりこの発明に至るまでの経過を説明する。
【００４６】
図７は、帯材を１／１ピッチで重ね巻きしたときのベルトカバーを示す説明図である。同図に示すように、このベルトカバーは、エッジ部において帯材を１／１ピッチで重ね巻きする。また、両帯材の巻き始め位置および巻き終わり位置も互いに周上の異なる位置にし、左の帯材では、巻き始めから左に巻き、折り返した後右に巻き、右の帯材はその逆とした。このようにすると、同図下のグラフ図に示したように、内側アパート、２重部分幅、２重部分内側アパートとも周上３６０度を通しての左右和が大きく偏ったものになる。これでは、ＵＦが低下してしまう。
【００４７】
図８は、図７のベルトカバーにおいて右の帯材の巻き始め位置と巻き終わり位置を周上１８０度ずらしたときのベルトカバーを示す説明図である。このようにすると、同図下のグラフ図に示したように、内側アパート、２重部分幅、２重部分内側アパートとも周上３６０度を通しての左右和が一定になるものの、２重部分幅のばらつきが蛇行成分をもち、さらに内側アパートの蛇行成分が大きくなり、図６の場合に比べて劣ってしまう。
【００４８】
図９は、図７の２重部分を帯材の１／２ピッチの重ね巻きで実現したときのベルトカバーを示す説明図である。両エッジ部での帯材の巻き方向はそれぞれ内側から外側へむかう方向とした。２重部分幅は周上３６０度を通して左右和が一定になるものの、内側アパート、および２重部分内側アパートが大きく乱れ、これがＵＦの低下につながってしまう。
【００４９】
図１０は、図９における右の帯材の巻き始め位置と巻き終わり位置を１８０度ずらしたときのベルトカバーを示した説明図である。このようにすると、同図下のグラフ図に示したように、２重部分幅は、周上３６０度を通しての左右和が一定になるものの、内側アパート、および２重部分内側アパートが大きく乱れ、ＵＦの低下につながる。
【００５０】
以上のように、この発明の実施の形態２に係る空気入りタイヤによれば、帯材を用いてベルトエッジ部に複数重ね巻きのベルトカバーを形成するときに発生する複数重ね部分幅、複数重ね部分内側アパート、および内側アパートの周上バラツキの左右和を常に一定にすることができる。その結果、ベルトカバーのＵＦ、特にＲＦＶ、ＲＲＯへの影響を極めて小さくすることが出来ることがわかった。これにより、タイヤの高速特性を向上させることができる。なお、実施の形態１と同様に、この発明における帯材のエッジ部の巻き付けピッチは、生産性や厚みの不均一等を考慮すれば、帯材の幅の１／２、１／３、１／４、１／５、１／６ピッチ程度が望ましい。
【００５１】
また、この発明も、上記ベルトカバーの周上バラツキを０にするために、巻き始め位置と巻き終わり位置、およびピッチ変更位置が周上同一位置であることが最も望ましいが、厳密に同一でなければ直ちに効果を失うものではない。つまり、巻き始め位置と巻き終わり位置は、所定範囲、具体的にはタイヤ中心角３０度以内程度であればある程度の効果は得られる。理想的にはタイヤ中心角１０度以内に収まることが望ましい。
【００５２】
（実施の形態３）
図１１は、この発明の実施の形態３に係る空気入りタイヤのベルトカバーを示した説明図である。なお、同図の下部のグラフ図は内側アパート、２重部分幅、２重部分内側アパートの順に示した。このベルトカバーは、実施の形態２のベルトカバーにおける双方の帯材の最内側に、さらに環状の帯材一巻きを加えたものである。この環状一巻きを加えることにより、内側アパートは、常に一定となる。
【００５３】
そして、当該ベルトカバーは、実施の形態２で説明したベルトカバーの特徴を承継し、２重部分幅、２重部分内側アパートの周上３６０度の総計が０となる。つぎに、実施の形態１、２と同様に、発明者の創意と工夫によりこの発明に至るまでの経過を説明する。
【００５４】
図１２は、帯材を１／１ピッチで重ね巻きしたときのベルトカバーを示す説明図である。同図に示すように、このベルトカバーは、最初に、双方の帯材の最内側に、環状の帯材を一巻きし、その上に帯材を１／１ピッチで重ね巻きする。また、両帯材の巻き始め位置および巻き終わり位置も互いに周上の異なる位置にし、左の帯材では、巻き始めから左に巻き、折り返した後右に巻き、右の帯材はその逆とした。このようにすると、同図下のグラフ図に示したように、内側アパートは当然一定になるが、２重部分幅、２重部分内側アパートとも周上３６０度を通しての左右和が大きく乱れたものになる。帯材成分ＲＦＶを測定したところ、３８Ｎと大きなものとなった。
【００５５】
図１３は、図１２における右の帯材の巻き始め位置と巻き終わり位置を周上１８０度ずらしたときのベルトカバーを示す説明図である。このようにすると、同図下のグラフ図に示したように、内側アパート、２重部分幅、２重部分内側アパートとも周上３６０度を通しての左右和が一定になるものの、２重部分内側アパートの蛇行成分が大きくなり、図１１の場合に比べて劣ってしまう。
【００５６】
図１４は、図１１の２重部分を帯材の１／２ピッチの重ね巻きで実現したときのベルトカバーを示す説明図である。両エッジ部での帯材の巻き方向はそれぞれ内側から外側へむかう方向とした。このようにすると、内側アパート、および２重部分幅は周上３６０度を通して左右和が一定になるものの、２重部分内側アパートが大きく乱れてしまった。このため、帯材成分ＲＦＶも３０Ｎと大きなものとなった。
【００５７】
図１５は、図１４における右の帯材の巻き始め位置と巻き終わり位置を周上１８０度ずらしたときのベルトカバーを示す説明図である。このようにすると、同図下のグラフ図に示したように、内側アパート、および２重部分幅は、周上３６０度を通しての左右和が一定になるものの、２重部分内側アパートが大きく乱れ、ＵＦの低下につながってしまう。
【００５８】
以上のように、この発明の実施の形態３に係る空気入りタイヤによれば、帯材を用いてベルトエッジ部に２重のベルトカバーを形成するときに発生する２重部分幅、２重部分内側アパート、および内側アパートの周上バラツキの左右和を常に一定にすることができる。その結果、ベルトカバーのＵＦ、特にＲＦＶ、ＲＲＯへの影響を極めて小さくすることが出来ることがわかった。これにより、タイヤの高速特性を向上させることができる。なお、実施の形態１、２と同様に、この発明における帯材のエッジ部の巻き付けピッチは、生産性や厚みの不均一等を考慮すれば、帯材の幅の１／２、１／３、１／４、１／５、１／６ピッチ程度が望ましい。
【００５９】
また、この発明も、巻き始め位置と巻き終わり位置、およびピッチ変更位置が周上同一位置であることが最も望ましいが、厳密に同一でなければ直ちに効果を失うものではない。つまり、巻き始め位置と巻き終わり位置は、所定範囲、具体的にはタイヤ中心角３０度以内程度であればある程度の効果は得られる。理想的にはタイヤ中心角１０度以内に収まることが望ましい。
【００６０】
（変形例）
図１６は、実施の形態１および２の変形例を示す説明図である。同図上部は、いわゆるフルカバー＋エッジカバー形式とフルカバー形式とを組み合わせた形式で、実施の形態１で説明したベルトカバーの下層に帯材を１重に巻いたものである。このような形式にしても、実施の形態１で説明した発明の効果は承継され、ＵＦを向上させると共に、ベルト剛性の向上させることができる。
【００６１】
また、同図下部に示したのが２重のエッジカバーとフルカバーを組み合わせた形式で、実施の形態２で説明したベルトカバーの上層に帯材を１重に巻いたものである。このような形式にしても、実施の形態２で説明した発明の効果は承継され、ＵＦを向上させると共に、ベルト剛性の向上させることができる。
【００６２】
【発明の効果】
以上説明したように、この発明に係る空気入りタイヤ（請求項１）によれば、帯材を用いてベルトエッジ部に２重以上のベルトカバーを形成するときに発生する２重巻き以上の部分の幅における周上バラツキを常に０にすることができる。その結果、ベルトカバーのＵＦ、特にＲＦＶ、ＲＲＯへの影響を極めて小さくすることが出来る。
【００６３】
また、この発明に係る空気入りタイヤ（請求項２）によれば、上記の効果に加え、帯材の巻き付けピッチを帯材の幅の１／２としたので、２重部分でベルトを適度に補強できると共に、使用する帯材の量も適当に収めることができる。
【００６４】
また、この発明に係る空気入りタイヤ（請求項３）によれば、上記の効果に加え、両帯材の最内側に、さらに環状の帯材一巻きを加えたので、赤道面から帯材内側までの距離が周上常に一定となり、これもＵＦの向上に資する。これらの結果、タイヤが高速回転したときの振動特性が向上する。
【００６５】
また、この発明に係る空気入りタイヤ（請求項４）によれば、帯材を用いてベルトエッジ部に２重以上のベルトカバーを形成するときに発生する２重巻き以上の部分の幅における周上バラツキを常に０にすることができる。その結果、ベルトカバーのＵＦ（特にＲＦＶ、ＲＲＯ）への影響を極めて小さくすることが出来る。したがって、タイヤの高速性能を向上させることができる。
【００６６】
また、この発明に係る空気入りタイヤ（請求項５）によれば、上記の効果に加え、帯材の巻き付けピッチを帯材の幅の１／２としたので、２重部分でベルトを適度に補強できると共に、使用する帯材の量も適当に収めることができる。
【００６７】
また、この発明に係る空気入りタイヤ（請求項６）によれば、請求項1乃至５に係る空気入りタイヤの効果を維持しつつ、ベルトカバーのベルト補強効果が向上する。
【００６８】
また、この発明に係る空気入りタイヤの製造方法（請求項７）によれば、製造する空気入りタイヤにおいて、帯材を用いてベルトエッジ部に２重巻き以上のベルトカバーを形成するときに発生する２重巻き以上の部分の幅における周上バラツキを常に０にすることができる。その結果、ベルトカバーのＵＦ、特にＲＦＶ、ＲＲＯへの影響を極めて小さくすることが出来る。
【００６９】
また、この発明に係る空気入りタイヤの製造方法（請求項８）によれば、上記の効果に加え、帯材の巻き付けピッチを帯材の幅の１／２としたので、タイヤは当該２重部分でベルトを適度に補強できると共に、使用する帯材の量も適当に収めることができる。
【００７０】
また、この発明に係る空気入りタイヤの製造方法（請求項９）によれば、空気入りタイヤにおいて、両帯材の最内側に、さらに環状の帯材一巻きを加えたので、赤道面から帯材内側までの距離が周上常に一定となり、これもＵＦの向上に資する。これらの結果、タイヤが高速回転したときの振動特性が向上する。
【００７１】
また、この発明に係る空気入りタイヤの製造方法（請求項１０）によれば、製造したタイヤにおいて、帯材を用いてベルトエッジ部に２重以上のベルトカバーを形成するときに発生する２重巻き以上の部分の幅における周上バラツキを常に０にすることができる。その結果、ベルトカバーのＵＦ、特にＲＦＶ、ＲＲＯへの影響を極めて小さくすることが出来る。したがって、タイヤの高速特性を向上させることができる。
【００７２】
また、この発明に係る空気入りタイヤの製造方法（請求項１１）によれば、上記の効果に加え、帯材の巻き付けピッチを帯材の幅の１／２としたので、２重部分でベルトを適度に補強できると共に、使用する帯材の量も適当に収めることができるタイヤを製造することができる。
【００７３】
また、この発明に係る空気入りタイヤの製造方法（請求項１２）によれば、帯材の総幅、２重以上の部分の総幅、および、帯材の２重以上部分の最内側に対する赤道面からの距離を左右相殺させることにより、帯材のアンバランスを解消させる。これにより、ＵＦの向上に資する空気タイヤを製造することができる。
【００７４】
また、この発明に係る空気入りタイヤの製造方法（請求項１３）によれば、請求項７乃至１２に係る空気入りタイヤの効果を維持しつつ、ベルトカバーのベルト補強効果が向上する。
【図面の簡単な説明】
【図１】この発明の実施の形態１に係る空気入りタイヤのベルトカバーを示した説明図である。
【図２】帯材の幅と同一ピッチで重ね巻きしたときのベルトカバーを示す説明図である。
【図３】図２の帯材の巻き始め位置と巻き終わり位置を周上同一位置にしたときベルトカバーを示す説明図である。
【図４】図１の２重部分を帯材の１／２ピッチの重ね巻きで実現したときのベルトカバーを示す説明図である。
【図５】図４のベルトカバーを帯材のセンター振り分けで実現したときのベルトカバーを示す説明図である。
【図６】実施の形態２に係る空気入りタイヤのベルトカバーを示した説明図である。
【図７】帯材を１／１ピッチで重ね巻きしたときのベルトカバーを示す説明図である。
【図８】図７の帯材の巻き始め位置と巻き終わり位置を周上同一位置にしたときのベルトカバーを示す説明図である。
【図９】図７の２重部分を帯材の１／２ピッチの重ね巻きで実現したときのベルトカバーを示す説明図である。
【図１０】図９の帯材の巻き始め位置と巻き終わり位置を周上１８０度ずらしたときのベルトカバーを示した説明図である。
【図１１】実施の形態３に係る空気入りタイヤのベルトカバーを示した説明図である。
【図１２】帯材を１／１ピッチで重ね巻きしたときのベルトカバーを示す説明図である。
【図１３】図１２の帯材の巻き始め位置と巻き終わり位置を周上１８０度ずらしたときのベルトカバーを示す説明図である。
【図１４】図１１の２重部分を帯材の１／２ピッチの重ね巻きで実現したときのベルトカバーを示す説明図である。
【図１５】図１４の帯材の巻き始め位置と巻き終わり位置を周上１８０度ずらしたときのベルトカバーを示す説明図である。
【図１６】実施の形態１および２の変形例を示す説明図である。
【図１７】従来の空気入りタイヤを示す説明図である。
【図１８】従来のベルトカバーの例を示す外観図である。
【図１９】従来のベルトカバーの例を示す外観図である。
【符号の説明】
１０１タイヤ
１０２カーカス
１０３ベルト
１０５ベルトカバー
１０６トレッド
１０７帯材[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a pneumatic tire and a method for manufacturing a pneumatic tire, and more particularly to a pneumatic tire having a belt cover that contributes to improvement of tire uniformity and a method for manufacturing the pneumatic tire.
[0002]
[Prior art]
FIG. 17 is an explanatory view showing a conventional pneumatic tire. Here, a typical radial tire will be described. The tire 101 is configured by a plurality of steel belts 103 and 104 overlapped with a carcass 102 in a radial direction of the tire. Further, in the tire, a belt cover 105 is disposed between the belts 103 and 104 and the tread 106 in order to improve high speed characteristics.
[0003]
The belt cover 105 is a discontinuity point when sheet-like ones are joined at one place on the circumference, and the portion becomes a discontinuity point (hereinafter abbreviated as UF), particularly RFV (Radial Force Variation radial force in the UF test). Fluctuation), RRO (Radial Run Out radial runout) is known to have an adverse effect. For this reason, the belt cover 105 is generally formed by winding a thin strip (strip material) in which an organic fiber cord is covered with rubber around a spiral (see, for example, Patent Documents 1 and 2). .
[0004]
FIG. 18 is an external view showing an example of a conventional belt cover. In this figure, a belt cover for 360 degrees is developed on a plane. A cross-sectional view when the belt cover is cut in the radial direction is shown in the lower part of the figure. As shown in the figure, the conventional belt cover starts to wind the belt material 107 starting from the position inside the belt edge by a predetermined dimension, winds from the right to the left on the paper, and then turns back from the left. Turn right, then turn back and spiral from right to left. Then, the winding ends on the inner side of a predetermined dimension from the edge of the belt opposite to the start position.
[0005]
When the belt material 107 is wound as described above, the belt material 107 is wound twice on the edge portion of the belt, the belt edge portion can be reinforced firmly, and the central portion is also formed of a single belt material 107. Can be reinforced. This winding method is often used in the V standard (up to a maximum of 240 km / h) and the W and Y standards (240 km / h or more) in the tire speed limit standards (JIS D4201, D4202).
[0006]
In addition to the above, in the H standard (up to a maximum of 210 km / h), etc., a double edge cover type in which the belt material 107 is wound only at the belt edge portion, or a full belt 107 wound from the edge portion to the center portion. There is also a cover type. For these belt covers, an appropriate type is selected and adopted in order to increase the rigidity of the belt, which is one of the factors affecting the high speed performance of the tire.
[0007]
FIG. 19 is an external view showing an example of a conventional belt cover. In the same figure as FIG. 18, the belt cover for 360 degrees is developed in a plane, and a sectional view when the belt cover is cut in the radial direction is shown in the lower part. In the figure, the upper part shows a double full cover + edge cover type, and a band material is wound on the lower layer of the full cover + edge cover type shown in FIG. 18 in a single layer. These are used for the purpose of further improving the belt rigidity.
[0008]
The specific winding method is to wrap the band material almost on the entire surface from either the left or right side, and then start the inner side of the specified dimension from the belt edge as in the full cover + edge cover type described above. After starting to wind the band material, wind it from right to left on the page, then turn it back and turn left to right, then turn back and turn right to left. Then, the winding ends on the inner side of a predetermined dimension from the edge of the belt opposite to the start position.
[0009]
Furthermore, the lower part of the figure shows a triple edge part and a central part wound in a single layer with a full cover type single band wound on the upper layer of the double edge cover type. is there. As a specific winding method, first, the left and right belt edge portions are wound from the inner side, folded back at the outer side, and then wound back to the inner side again. From there, the strip is wound once on almost the entire surface from either the left or right side.
[0010]
[Patent Document 1]
JP-A-4-355121 (pages 2-4, FIGS. 2, 4)
[Patent Document 2]
Japanese Utility Model Publication No. 62-178201 (page 6, FIGS. 4, 5)
[0011]
[Problems to be solved by the invention]
However, the belt cover of the pneumatic tire according to the above prior art can be improved in terms of rigidity and high speed characteristics, but on the other hand, when viewed from the viewpoint of UF which affects the vibration characteristics of the tire, the belt material is spirally wound. The belt cover itself has a problem that it is difficult to always ensure uniformity on the circumference of the belt cover. Specifically, in the case of a structure that covers only the belt width itself, the total width of the belt cover itself, the width of two or more overlapping winding portions, the right and left sum of the distance from the tire equator line to the overlapping winding portion, or the belt edge only. Circumferential variation occurs in the left-right sum of the distance from the equator line to the inside of the cover. Tires lacking in UF adversely affect vehicle vibration and noise, particularly when rotating at high speeds.
[0012]
Therefore, the present invention has been made in view of the above, and an object thereof is to provide a pneumatic tire having a belt cover that contributes to improvement of tire uniformity and a method for manufacturing the pneumatic tire.
[0013]
[Means for Solving the Problems]
In order to achieve the above-mentioned object, the pneumatic tire according to claim 1 is a band member at each edge portion so as to cover at least both edge portions of the belt on the radially outer side of the belt provided outside the carcass. In the pneumatic tire having a belt cover formed by winding the belt material, the belt material is wound around the belt material at a constant pitch, and the winding start position and the winding end position of both the belt material are all within a predetermined range in the circumferential direction. The belt material is wound so as to be accommodated, and both the band members are wound in the same direction in the width direction of the belt.
[0014]
When the wrapping portion, that is, the lap winding portion of a plurality of times, is formed on the belt edge portion with the winding pitch of the belt material forming the belt cover being constant, the width of the lap winding portion becomes uniform on the circumference. In addition, when the belt material is wound in one direction of the belt width direction (the direction from the left or right to the other) while the winding start and the winding end position of the belt on the left and right are within a predetermined range in the circumferential direction, The left-right sum of the distance between the innermost side of the band material and the tire equatorial plane and the distance between the innermost side of the plurality of overlapping winding portions and the equatorial plane becomes uniform on the circumference.
[0015]
In the pneumatic tire according to claim 2, in the pneumatic tire, the constant pitch is a pitch at which a half of the width of the strip is overlapped.
[0016]
In the pneumatic tire according to claim 3, in the pneumatic tire, an annular strip is further added to the innermost side of both the strips.
[0017]
Further, in the pneumatic tire according to claim 4, a double or more portion is formed by winding a band material at a position covering at least both edge portions of the belt provided on the outer side of the carcass in the radial direction. In the pneumatic tire having a belt cover in which a single portion is formed by winding the band material at a central portion, the double or more portions are formed by overlapping the band material at a constant pitch, In the portion, the strip is wound at a pitch of the same length as the width of the strip, and the winding start position and winding end position of the strip in the double or more portions, and the double or more portions Is wound so that all the pitch change positions at the boundary between the belt and the single portion are within a predetermined range in the circumferential direction, and the belt is wound in one direction in the width direction of the belt. Than it is.
[0018]
Further, in the pneumatic tire according to claim 5, in the pneumatic tire, the constant pitch is a pitch at which a half of the width of the strip is overlapped.
[0019]
A pneumatic tire according to a sixth aspect is a pneumatic tire according to any one of the first to fifth aspects, wherein a belt material wound in a single layer is stacked as a lower layer or an upper layer of the belt cover.
[0020]
In the present invention, the pneumatic tire according to any one of claims 1 to 5 is combined with a single full-band material. Therefore, as a whole, a belt cover having three or more portions and a single portion, or three or more portions and a double portion is formed, and the belt is strongly reinforced while improving UF.
[0021]
According to a seventh aspect of the present invention, there is provided a pneumatic tire manufacturing method in which a belt is wound around a belt member at each edge portion so as to cover at least both edge portions of the belt on a radially outer side of the belt provided on the outer side of the carcass. In the method for manufacturing a pneumatic tire for forming a cover, the belt cover is formed by overlappingly winding the band material at a constant pitch, and the winding start position and the winding end position of both the band materials are all within a predetermined range in the circumferential direction. In addition, both the belt members are wound in the same direction in the width direction of the belt.
[0022]
When a winding portion of the belt material forming the belt cover is made constant and a lap winding portion, that is, a portion of double winding or more is formed on the belt edge portion, the width of the portion of double winding or more becomes uniform on the circumference. Also, the start and end winding positions and the pitch change position on the left and right sides of the belt material are all within a predetermined range in the circumferential direction, and the belt is banded in one direction (the direction from the left or right to the other) in the belt width direction. When the material is wound, the distance between the innermost side of the belt and the tire equatorial plane at the edge portion and the left-right sum of the distance from the innermost side and the equatorial plane of the double winding or more becomes uniform on the circumference.
[0023]
Moreover, the manufacturing method of the pneumatic tire according to claim 8 is such that, in the manufacturing method of the pneumatic tire, the constant pitch is a pitch at which ½ of the width of the strip is overlapped. .
[0024]
According to a ninth aspect of the present invention, there is provided a method for manufacturing a pneumatic tire, wherein in the method for manufacturing a pneumatic tire, a further annular strip is added to the innermost side of both the strips.
[0025]
Moreover, the manufacturing method of the pneumatic tire according to claim 10 is the outer side in the radial direction of the belt provided on the outer side of the carcass, and at least two edge portions of the belt are covered with the belt material wound at a position that covers at least both edges. In the method of manufacturing a pneumatic tire having a belt cover that forms a portion by forming a single portion by winding the band material at a central portion, the double or more portions are formed by wrapping the band material at a constant pitch. In the single portion, the strip is wound at a pitch having the same length as the width of the strip, and the winding start position and end position of the strip at the edge portion, and the single portion and the 2 Wound so that all the pitch change positions at the boundary with the heavy or more portion are within the predetermined range in the circumferential direction, and the belt is wound in one direction in the width direction of the belt A.
[0026]
Further, in the method for manufacturing a pneumatic tire according to claim 11, in the method for manufacturing a pneumatic tire, the constant pitch is a pitch at which ½ of the width of the strip is overlapped.
[0027]
Moreover, the pneumatic tire manufacturing method according to claim 12 includes the total width of the strip wound on the left side when the pneumatic tire is viewed from the radial direction, and the width of the strip wound on the right side. The left-right sum of the total width is set to 0, and the left-right sum of the total width in which the strip is wound more than twice on the left side of the tire equator and the total width in which the width is wound more than twice on the right side is set to 0. In addition, the belt cover is formed by setting the right and left sum of the distance from the tire equatorial plane to the innermost side of the portion where the belt material is double or more to 0.
[0028]
Since the belt cover is formed by spirally winding the band material, the distance from the tire equatorial plane to the innermost portion of the portion where the band material is doubled or larger increases or decreases over 360 degrees on the circumference. In the present invention, the imbalance of the strip is eliminated by canceling the distance from the equatorial plane that increases or decreases on the circumference in this way. Thereby, the pneumatic tire which contributes to improvement of UF can be manufactured.
[0029]
Further, the pneumatic tire manufacturing method according to claim 13 is wound in a single layer as a lower layer or an upper layer of the belt cover of the pneumatic tire according to the pneumatic tire manufacturing method according to claims 7 to 12. It is made up of overlapping strips.
[0030]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the present invention will be described in detail with reference to the drawings. Note that the present invention is not limited to the embodiments. The constituent elements of this embodiment include those that can be easily replaced by those skilled in the art or those that are substantially the same.
[0031]
(Embodiment 1)
1 is an explanatory view showing a belt cover of a pneumatic tire according to Embodiment 1 of the present invention. The upper figure in this figure is a 360 degree belt cover developed on a plane. The lower part of the upper figure shows a sectional view when the belt cover is cut in the radial direction. The lower figure is a graph showing the tire characteristics corresponding to the angles in the upper figure. The vertical axis is the circumferential angle, the horizontal axis is the total width from the left, the double part width, the left-right sum of the distance from the tire equatorial plane to the double part inside (hereinafter referred to as the double part inside apartment), and It is a strip material component RFV waveform.
[0032]
As shown in the figure, this belt cover is formed by wrapping the belt material at a constant pitch so as to cover it with edge portions which are both ends of a belt (not shown). Here, the fixed pitch is a pitch that overlaps half the width of the strip. In the central portion, the strip is wound at a pitch having the same length as the width of the strip. That is, a double winding portion of the band material is formed at the edge portion, and a single winding portion is formed at the center portion. In addition, the band material is wound so that the winding start position and the winding end position of the band material at the edge part and the pitch change position at the boundary between the edge part and the central part are all the same position in the circumferential direction. The strip is further wound in one direction in the width direction of the belt, here from left to right.
[0033]
When the belt cover is formed by winding the belt material as described above, as shown in the total width and the double portion width in the lower part of the figure, the left and right sum of the fluctuations in the total width and the width of the double portion becomes constant on the circumference. Become. In the graph, the total width and double portion width of each of the left and right edge portions are indicated by dotted lines, and the solid line is the sum of the left and right sides. Also, when the belt material winding start position, the winding end position, and the pitch change position are arranged at the same position in the circumferential direction, and the belt material is wound in one direction (here, left to right) in the belt width direction, The sum of the left and right sides of the apartment inside the double part is constant throughout the 360 degrees.
[0034]
Finally, the band material component of the RFV waveform in the UF could be kept lower than 13N and other types described later. The strip material component RFV waveform is obtained by preparing a plurality of pneumatic tires manufactured under a predetermined condition, measuring RFV, and extracting only the influence of the strip material component. Thus, winding the strip so that the strip winding start position and the winding end position, which are discontinuous points of the strip, are all in the same position in the circumferential direction causes a peak of the RFV waveform so far. It has been avoided.
[0035]
The present invention is characterized in that RFV can be kept low in combination with other conditions for winding the strip. Next, the process up to the present invention will be described by the inventor's inventive idea and device. This makes it possible to understand the outstanding points of interest and the effects of the present invention.
[0036]
FIG. 2 is an explanatory view showing the belt cover when it is overlapped and wound at the same pitch as the width of the strip. The upper figure in this figure is a 360 degree belt cover developed on a plane. The lower part of the upper figure shows a sectional view when the belt cover is cut in the radial direction. The lower figure is a graph showing the tire characteristics corresponding to the angles in the upper figure. The vertical axis represents the circumferential angle, and the horizontal axis represents the total width, double part width, double part inside apartment, and strip material component RFV waveform from the left, respectively. Hereinafter, description will be made with reference to the same figure.
[0037]
As shown in the figure, this belt cover is formed by winding an edge portion of a belt member at the same pitch as the width (hereinafter referred to as 1/1 pitch). Also, the winding start position and the winding end position of the band material are also set at different positions on the circumference, wound left from the start of winding, folded back, wound right, folded back, and wound left. In this case, as shown in the graph below the figure, the left and right sums through 360 degrees are greatly disturbed in both the double part width and the double part inside apartment. As a result, the strip material component RFV waveform also increased and became a maximum value of 26N.
[0038]
FIG. 3 is an explanatory view showing the belt cover when the winding start position and the winding end position of the strip of FIG. 2 are set to the same position on the circumference. In addition, since the total number of windings of the strip is increased by 1/2 to obtain an integer winding, the shape of the right end of the belt cover is different by 1/2 of the strip. In this way, when the winding start position and winding end position of the strip are set to the same position on the circumference, the left-right sum of the double-part inner apartment is constant throughout 360 degrees, but the total width and double-part width are greatly disturbed. As a result, the strip component RFV waveform could not be reduced to 21N.
[0039]
FIG. 4 is an explanatory diagram showing a belt cover when the double portion of FIG. 1 is realized by lap winding of a band material at 1/2 pitch. The total number of windings of the band material was non-integer winding. Thus, even if the strip is wound in one direction in the width direction, the winding start position and the winding end position are not the same position on the circumference, so the total width, the double portion width, and the double portion inner apartment are greatly disturbed. . As a result, the band component RFV waveform could not be reduced to 28N. It should be noted that the same result is obtained even if the strip is wound into an integer.
[0040]
FIG. 5 is an explanatory view showing the belt cover when the belt cover of FIG. 4 is realized by center distribution of the band material. When the strips are centered in this way, the total width, double portion width, and double portion inside apartment are greatly disturbed through 360 degrees. As a result, the strip material component RFV waveform could not be as small as 18N. In the UF test for obtaining this RFV, since the tire sizes are different, it cannot be discussed strictly in the same row as the belt cover described above, but the result can be estimated from the fact that the total width and the like are greatly disturbed.
[0041]
As described above, according to the pneumatic tire according to the first embodiment of the present invention, a plurality of overlapping winding part widths that are generated when a belt cover is formed on the belt edge portion using a belt material. In addition, it is possible to always keep the variation in the circumference of the right and left sum of the apartments inside the plurality of wrap-up portions constant. As a result, it was found that the influence of the belt cover on UF, particularly RFV and RRO, can be extremely reduced. Thereby, the high-speed characteristic of a tire can be improved. Note that the winding pitch of the edge portion of the strip in the present invention is 1/2, 1/3, 1/4, 1/5, 1 / of the width of the strip in consideration of productivity and uneven thickness. About 6 pitches are desirable.
[0042]
Further, in the present invention, it is most desirable that the winding start position, the winding end position, and the pitch change position are the same position on the circumference in order to make the belt cover circumferential dispersion as described above zero. If it is not the same, the effect is not lost immediately. That is, a certain degree of effect can be obtained if the winding start position and the winding end position are within a predetermined range, specifically, within about 30 degrees of the tire center angle. Ideally, it should be within 10 degrees of the tire center angle. Moreover, this invention is applicable not only to a radial tire but also to a bias tire having a belt.
[0043]
(Embodiment 2)
FIG. 6 is an explanatory view showing a belt cover of a pneumatic tire according to Embodiment 2 of the present invention. In addition, the figure differs from FIGS. 1-5, and the lower graph was shown in order of the inner apartment, double part width, and double part inner apartment which will be described later. In this belt cover, the band material is overlapped and wound at a constant pitch at the edge portions that are both ends of the belt (not shown), and the winding start position and the winding end position of both the band materials are all in the same position in the circumferential direction. Rolled up like so. Here, the fixed pitch is ½ pitch. In addition, the present invention is characterized in that both strips are wound in the same direction in the width direction of the belt, here from right to left.
[0044]
When the belt winding forming the belt cover has a constant winding pitch, and the overlapped portion, that is, the portion of the double winding or more is formed on the belt edge portion, the sum of the left and right in the width of the portion of the double winding or more is 360 degrees in the circumference. It becomes constant through. Also, when the winding start position and the winding end position on the left and right sides of the band material are arranged at the same position in the circumferential direction and the band material is wound in one direction in the width direction of the belt, the innermost side of the band material at both edge portions And the distance from the tire equatorial plane, that is, the left-right sum of the inner apartment and the double-part inner apartment is constant throughout 360 degrees on the circumference. Thereby, the factor which has a bad influence with respect to UF can be eliminated.
[0045]
As described above, the belt cover according to the second embodiment winds the band material so that the winding start position and the winding end position of the band material at both edge portions are the same position. This has been avoided so far as it causes a peak of the RFV waveform as in the first embodiment. Here, as in the first embodiment, the process up to the present invention will be described by the inventor's inventiveness and device.
[0046]
FIG. 7 is an explanatory view showing a belt cover when the belt is overlapped and wound at a 1/1 pitch. As shown in the figure, this belt cover is formed by overlapping and winding a band material at a 1/1 pitch at an edge portion. Also, the winding start position and winding end position of both strips should be different from each other on the circumference, with the left strip being wound from the start to the left, folded back and wound to the right, and the right strip being the opposite did. In this way, as shown in the graph below the figure, the left and right sums through 360 degrees in the circumference are greatly biased for the inner apartment, the double part width, and the double part inner apartment. This will decrease the UF.
[0047]
FIG. 8 is an explanatory view showing the belt cover when the winding start position and winding end position of the right belt member are shifted 180 degrees in the circumference in the belt cover of FIG. In this way, as shown in the graph below the figure, the inner part, the double part width, and the double part inner apartment both have a uniform left and right sum through 360 degrees, but the double part width The variation has a meandering component, and the meandering component of the inner apartment becomes larger, which is inferior to the case of FIG.
[0048]
FIG. 9 is an explanatory view showing a belt cover when the double portion of FIG. 7 is realized by lap winding of a band material at 1/2 pitch. The winding direction of the strips at both edge portions was the direction from the inside to the outside. Although the width of the double portion is constant through 360 degrees on the circumference, the inside apartment and the inside of the double portion are greatly disturbed, which leads to a decrease in UF.
[0049]
FIG. 10 is an explanatory view showing the belt cover when the winding start position and winding end position of the right band in FIG. 9 are shifted by 180 degrees. In this way, as shown in the graph below the figure, the double part width is constant in the lateral sum through 360 degrees on the circumference, but the inner apartment and the double part inner apartment are greatly disturbed. This leads to a decrease in UF.
[0050]
As described above, according to the pneumatic tire according to the second embodiment of the present invention, the multiple overlap portion width and the multiple overlap generated when the belt cover is formed on the belt edge portion using the belt material. The left-right sum of the partial inner apartment and the variation in the circumference of the inner apartment can always be made constant. As a result, it was found that the influence of the belt cover on UF, particularly RFV and RRO, can be extremely reduced. Thereby, the high-speed characteristic of a tire can be improved. As in the first embodiment, the winding pitch of the edge portion of the strip in the present invention is 1/2, 1/3, 1 of the width of the strip in consideration of productivity, thickness non-uniformity, and the like. / 4, 1/5, and 1/6 pitch are desirable.
[0051]
Also in this invention, it is most desirable that the winding start position, the winding end position, and the pitch change position are the same position on the circumference in order to reduce the circumferential variation of the belt cover to 0, but it must be exactly the same. If it does not immediately lose its effectiveness. That is, a certain degree of effect can be obtained if the winding start position and the winding end position are within a predetermined range, specifically, within about 30 degrees of the tire center angle. Ideally, it should be within 10 degrees of the tire center angle.
[0052]
(Embodiment 3)
FIG. 11 is an explanatory view showing a belt cover of a pneumatic tire according to Embodiment 3 of the present invention. In the lower part of the figure, the inner apartment, the double part width, and the double part inner apartment are shown in this order. This belt cover is obtained by further adding one roll of an annular strip to the innermost side of both strips of the belt cover of the second embodiment. By adding this one turn, the inner apartment is always constant.
[0053]
The belt cover inherits the characteristics of the belt cover described in the second embodiment, and the total of 360 degrees on the circumference of the double part width and double part inside apartment becomes zero. Next, as in Embodiments 1 and 2, the process up to the present invention will be described by the inventor's inventiveness and ingenuity.
[0054]
FIG. 12 is an explanatory view showing a belt cover when the belt is overlapped and wound at a 1/1 pitch. As shown in the figure, in this belt cover, first, an annular strip is wound on the innermost side of both strips, and the strip is wound on the belt with a 1/1 pitch. Also, the winding start position and winding end position of both strips should be different from each other on the circumference, with the left strip being wound from the start to the left, folded back and wound to the right, and the right strip being the opposite did. In this case, as shown in the graph below the figure, the inside apartment is naturally constant, but the double part width and the double part inside apartment are greatly disturbed in the left-right sum through 360 degrees on the circumference. become. When the strip material component RFV was measured, it was as large as 38N.
[0055]
FIG. 13 is an explanatory view showing the belt cover when the winding start position and winding end position of the right band member in FIG. 12 are shifted by 180 degrees in the circumference. In this way, as shown in the graph below, the inner apartment, the double part width, the double part inner apartment, the left and right sum through 360 degrees on the circumference is constant, but the double part inner apartment The meandering component becomes larger and inferior to the case of FIG.
[0056]
FIG. 14 is an explanatory view showing a belt cover when the double portion of FIG. 11 is realized by lap winding of a band material at 1/2 pitch. The winding direction of the strips at both edge portions was the direction from the inside to the outside. In this way, the inner apartment and the double part width are constant in the left-right sum through 360 degrees on the circumference, but the double part inner apartment is greatly disturbed. For this reason, the strip material component RFV was as large as 30N.
[0057]
FIG. 15 is an explanatory view showing the belt cover when the winding start position and winding end position of the right band member in FIG. 14 are shifted by 180 degrees in the circumference. In this way, as shown in the lower graph, the inner apartment and the double part width are constant in the left and right sum through 360 degrees on the circumference, but the double part inner apartment is greatly disturbed. This leads to a decrease in UF.
[0058]
As described above, according to the pneumatic tire according to the third embodiment of the present invention, the double portion width and the double portion that are generated when the double belt cover is formed on the belt edge portion using the belt material. The left-right sum of the inner apartment and the variation in the circumference of the inner apartment can always be made constant. As a result, it was found that the influence of the belt cover on UF, particularly RFV and RRO, can be extremely reduced. Thereby, the high-speed characteristic of a tire can be improved. As in the first and second embodiments, the winding pitch of the edge portion of the strip in the present invention is 1/2 or 1/3 of the width of the strip in consideration of productivity, uneven thickness, and the like. 1/4, 1/5, and 1/6 pitch are desirable.
[0059]
In the present invention, it is most desirable that the winding start position, the winding end position, and the pitch change position are the same position on the circumference, but the effect is not immediately lost unless they are exactly the same. That is, a certain degree of effect can be obtained if the winding start position and the winding end position are within a predetermined range, specifically, within about 30 degrees of the tire center angle. Ideally, it should be within 10 degrees of the tire center angle.
[0060]
(Modification)
FIG. 16 is an explanatory diagram showing a modification of the first and second embodiments. The upper part of the figure is a combination of a so-called full cover + edge cover type and a full cover type, in which a belt material is wound on the lower layer of the belt cover described in the first embodiment in a single layer. Even in such a format, the effect of the invention described in the first embodiment is inherited, and the UF can be improved and the belt rigidity can be improved.
[0061]
In the lower part of the figure, a double edge cover and a full cover are combined, and a belt material is wound on the upper layer of the belt cover described in the second embodiment in a single layer. Even in such a form, the effect of the invention described in the second embodiment is inherited, and the UF can be improved and the belt rigidity can be improved.
[0062]
【The invention's effect】
As described above, according to the pneumatic tire according to the present invention (Claim 1), the portion of the double winding or more generated when the belt cover is formed on the belt edge portion using the belt material. The circumferential variation in the width can be always zero. As a result, the influence of the belt cover on UF, particularly RFV and RRO can be extremely reduced.
[0063]
Further, according to the pneumatic tire according to the present invention (Claim 2), in addition to the above-described effect, the winding pitch of the band material is set to ½ of the width of the band material, so that the belt is moderately formed in the double portion. In addition to being able to reinforce, the amount of strip used can also be properly accommodated.
[0064]
Moreover, according to the pneumatic tire according to the present invention (Claim 3), in addition to the above-described effect, a further annular belt is added to the innermost side of the two belt members, so that the inner side of the belt member from the equator surface. The distance is always constant on the circumference, which also contributes to the improvement of UF. As a result, vibration characteristics when the tire rotates at high speed are improved.
[0065]
Further, according to the pneumatic tire according to the present invention (Claim 4), the circumference in the width of the portion of the double winding or more generated when the belt cover is formed on the belt edge portion using the belt material. The upper variation can always be zero. As a result, the influence of the belt cover on the UF (especially RFV and RRO) can be extremely reduced. Therefore, the high speed performance of the tire can be improved.
[0066]
Further, according to the pneumatic tire according to the present invention (Claim 5), in addition to the above-described effect, the winding pitch of the strip is set to ½ of the width of the strip, so that the belt is moderately secured in the double portion. In addition to being able to reinforce, the amount of strip used can also be properly accommodated.
[0067]
According to the pneumatic tire of the present invention (Claim 6), the belt reinforcing effect of the belt cover is improved while maintaining the effect of the pneumatic tire according to Claims 1 to 5.
[0068]
Further, according to the method for manufacturing a pneumatic tire according to the present invention (Claim 7), in the manufactured pneumatic tire, the belt tire is formed when a belt cover having a double winding or more is formed on the belt edge portion. The circumferential variation in the width of the portion of the double winding or more to be made can always be zero. As a result, the influence of the belt cover on UF, particularly RFV and RRO can be extremely reduced.
[0069]
According to the method for manufacturing a pneumatic tire according to the present invention (Claim 8), in addition to the above effect, the winding pitch of the strip is set to ½ of the width of the strip. The belt can be properly reinforced at the portion, and the amount of band material to be used can be appropriately accommodated.
[0070]
According to the method for manufacturing a pneumatic tire according to the present invention (Claim 9), in the pneumatic tire, since one further turn of the annular band material is added to the innermost side of both the band members, The distance to the inside of the material is always constant on the circumference, which also contributes to the improvement of UF. As a result, vibration characteristics when the tire rotates at high speed are improved.
[0071]
Further, according to the method for manufacturing a pneumatic tire according to the present invention (claim 10), in the manufactured tire, a double is generated when a belt cover is used to form a double or more belt cover at the belt edge portion. The circumferential variation in the width of the portion beyond the winding can always be zero. As a result, the influence of the belt cover on UF, particularly RFV and RRO can be extremely reduced. Therefore, the high speed characteristics of the tire can be improved.
[0072]
According to the method for manufacturing a pneumatic tire according to the present invention (claim 11), in addition to the above effect, the winding pitch of the strip is set to ½ of the width of the strip. Can be properly reinforced, and a tire that can appropriately accommodate the amount of band material to be used can be manufactured.
[0073]
According to the pneumatic tire manufacturing method of the present invention (Claim 12), the total width of the strip material, the total width of the double or more portion, and the equator with respect to the innermost side of the double or more portion of the strip material By canceling the distance from the surface to the left and right, the imbalance of the strip is eliminated. Thereby, the pneumatic tire which contributes to improvement of UF can be manufactured.
[0074]
According to the method for manufacturing a pneumatic tire according to the present invention (claim 13), the belt reinforcing effect of the belt cover is improved while maintaining the effect of the pneumatic tire according to claims 7 to 12.
[Brief description of the drawings]
FIG. 1 is an explanatory view showing a belt cover of a pneumatic tire according to Embodiment 1 of the present invention.
FIG. 2 is an explanatory view showing a belt cover when it is lap-wound at the same pitch as the width of the strip.
FIG. 3 is an explanatory view showing a belt cover when the winding start position and winding end position of the band shown in FIG. 2 are set to the same position on the circumference.
4 is an explanatory view showing a belt cover when the double portion of FIG. 1 is realized by lap winding of a band material at 1/2 pitch. FIG.
FIG. 5 is an explanatory view showing the belt cover when the belt cover of FIG. 4 is realized by center distribution of the belt material.
6 is an explanatory view showing a belt cover of a pneumatic tire according to Embodiment 2. FIG.
FIG. 7 is an explanatory view showing a belt cover when a belt is overlapped and wound at a 1/1 pitch.
8 is an explanatory view showing a belt cover when the winding start position and the winding end position of the band material of FIG. 7 are set to the same position on the circumference.
FIG. 9 is an explanatory view showing a belt cover when the double portion of FIG. 7 is realized by lap winding of a band material at 1/2 pitch.
10 is an explanatory view showing a belt cover when the winding start position and winding end position of the band shown in FIG. 9 are shifted by 180 degrees on the circumference. FIG.
FIG. 11 is an explanatory view showing a belt cover of a pneumatic tire according to a third embodiment.
FIG. 12 is an explanatory view showing a belt cover when a belt is overlapped and wound at a 1/1 pitch.
13 is an explanatory view showing the belt cover when the winding start position and winding end position of the band shown in FIG. 12 are shifted by 180 degrees on the circumference.
14 is an explanatory view showing a belt cover when the double portion of FIG. 11 is realized by lap winding of a band material at 1/2 pitch. FIG.
15 is an explanatory view showing the belt cover when the winding start position and winding end position of the band shown in FIG. 14 are shifted by 180 degrees on the circumference.
FIG. 16 is an explanatory diagram showing a modification of the first and second embodiments.
FIG. 17 is an explanatory view showing a conventional pneumatic tire.
FIG. 18 is an external view showing an example of a conventional belt cover.
FIG. 19 is an external view showing an example of a conventional belt cover.
[Explanation of symbols]
101 tires
102 Carcass
103 belt
105 belt cover
106 tread
107 Band material

Claims

In a pneumatic tire having a belt cover by wrapping a band material at each edge portion so as to cover at least both edge portions of the belt on the radially outer side of the belt provided outside the carcass,
The belt cover is wound so that the band material is rolled over at a constant pitch, and the winding start position and the winding end position of both the band materials are all within a predetermined range in the circumferential direction, and both the band covers are wound. A pneumatic tire, wherein the material is wound in the same direction in the width direction of the belt.

2. The pneumatic tire according to claim 1, wherein the constant pitch is a pitch at which half of the width of the strip is overlapped.

The pneumatic tire according to any one of claims 1 and 2, further comprising an annular band wound on the innermost side of both the band members.

Two or more portions are formed by winding the belt material at a position covering at least both edge portions of the belt provided on the outer side of the carcass, and the belt is wound around the central portion by winding the belt material In a pneumatic tire having a belt cover formed with a single portion,
In the two or more portions, the band material is overlapped and wound at a constant pitch. In the single portion, the band material is wound at a pitch having the same length as the width of the band material, and the double or more portions are wound. The belt material is wound so that the winding start position and the winding end position of the band material and the pitch change position at the boundary between the double part and the single part are all within a predetermined range in the circumferential direction, The pneumatic tire is wound around in one direction in the width direction of the belt.

5. The pneumatic tire according to claim 4, wherein the constant pitch is a pitch at which half of the width of the strip is overlapped. 6.

The pneumatic tire according to any one of claims 1 to 5, wherein a belt material wound in a single layer is stacked as a lower layer or an upper layer of the belt cover of the pneumatic tire according to any one of claims 1 to 5.

In the method of manufacturing a pneumatic tire in which a belt cover is formed by wrapping a band member at each edge portion so as to cover at least both edge portions of the belt on the outer side in the radial direction of the belt provided outside the carcass,
The belt cover is wound so that the strips are wound at a constant pitch, and the winding start position and the winding end position of both the strips are all within a predetermined range in the circumferential direction, and both the strips are wound. A method for producing a pneumatic tire, wherein the pneumatic tire is wound in the same direction in the width direction of the belt.

The method for manufacturing a pneumatic tire according to claim 7, wherein the constant pitch is a pitch at which ½ of the width of the strip is overlapped.

The method for manufacturing a pneumatic tire according to any one of claims 7 and 8, further comprising adding an annular belt to the innermost side of both the band members.

The belt is provided outside the carcass in the radial direction, and at least a portion covering both edge portions of the belt is formed with two or more portions wound around the belt, and the belt is wound around the central portion. In the manufacturing method of the pneumatic tire which has a belt cover which forms a single part,
The two or more portions are overlapped with the strip at a constant pitch, the single portion is wound with the strip at a pitch equal to the width of the strip, and the band of the edge portion Winding so that the pitch start position and the winding end position of the material, and the pitch change position at the boundary between the single part and the double part or more are all within a predetermined range in the circumferential direction, and the band material, A method for manufacturing a pneumatic tire, characterized by winding in one direction in the width direction of the belt.

The method for manufacturing a pneumatic tire according to claim 10, wherein the constant pitch is a pitch at which a half of the width of the strip is overlapped.

When the pneumatic tire is viewed from the radial direction, the left-right sum of the width of the strip wound on the left side of the tire equator and the width of the strip wound on the right side is set to 0, and the tire equatorial plane The left and right sum of the total width in which the strip is wound more than twice on the left side and the total width in which the strip is wound more than twice on the right side is 0, and the innermost part of the portion where the strip is more than double A method for manufacturing a pneumatic tire, characterized in that a belt cover is formed by setting a right and left sum of a distance from a tire equatorial plane to zero.

A method for manufacturing a pneumatic tire, wherein a belt material wound in a single layer is stacked as a lower layer or an upper layer of the belt cover of the pneumatic tire according to the method for manufacturing a pneumatic tire according to claim 7 to 12. .