JP4367593B2

JP4367593B2 - Tire vulcanizer and tire vulcanizing method

Info

Publication number: JP4367593B2
Application number: JP2000134974A
Authority: JP
Inventors: 英一飯田
Original assignee: Yokohama Rubber Co Ltd
Current assignee: Yokohama Rubber Co Ltd
Priority date: 2000-05-08
Filing date: 2000-05-08
Publication date: 2009-11-18
Anticipated expiration: 2020-05-08
Also published as: JP2001315128A

Description

【０００１】
【発明の属する技術分野】
本発明は、空気入りタイヤを加硫するための加硫機及び加硫方法に関し、さらに詳しくは、ブラダーレス構造を有し、しかもビード形状の再現性を高めるようにしたタイヤ加硫機及びタイヤ加硫方法に関する。
【０００２】
【従来の技術】
通常のタイヤ加硫では、加硫機に投入されたグリーンタイヤ（未加硫タイヤ）の内側にブラダーと呼ばれるゴム製の袋を挿入し、このブラダーの内部に加熱媒体としてスチームや温水を導入し、この状態でタイヤを加硫している。ところが、ブラダーを用いる従来の加硫方法では、ブラダーの作製や加硫機へのセットに多大な工数を要するだけでなく、エネルギーロスが大きくて加硫に時間が掛かるため、タイヤ生産効率の向上やコストの低減にとって障害となる点が多い。
【０００３】
上記ブラダーを用いた加硫方法における不都合を解消するために、例えば、特開平２−２１２１０５号公報や特開平６−７１６５２号公報には、ブラダーレス加硫機が提案されている。これらブラダーレス加硫機は、ゴム製のブラダーの替わりに、タイヤビード部を押さえ込む機械的な手段を備えている。
【０００４】
しかしながら、ブラダーレス加硫機では、タイヤビード部を押さえ込む機械的な手段がグリーンタイヤのビード部のボリュームに応じて柔軟に変位することができないので、そのボリュームが大きいときにはビード部を押し潰し、ボリュームが小さいときには空隙が残存し、その結果、ビード形状の再現性が低くなるという問題があった。
【０００５】
【発明が解決しようとする課題】
本発明の目的は、ブラダーレス構造を有し、しかもビード形状の再現性を高めることを可能にしたタイヤ加硫機及びタイヤ加硫方法を提供することにある。
【０００６】
【課題を解決するための手段】
上記目的を達成するための本発明のタイヤ加硫機は、グリーンタイヤを収容する金型の中心位置に、一対のタイヤビード部をそれぞれ前記金型のビードリングに対して抑えつける一対の把持部材をタイヤ径方向及びタイヤ軸方向に変位させる中心機構を配設し、前記ビードリングと前記把持部材とをタイヤ軸方向に延びる円筒状の摺動面に沿って互いに摺動自在に構成し、前記ビードリングに対する前記把持部材の押し込み量を、把持部材に負荷するタイヤ軸方向の圧力に基づいて制御することにより、前記タイヤビード部の体積に応じて変更自在にして、タイヤビード部の体積が大きい場合は、把持部材の押し込み量を少なくし、タイヤビード部の体積が小さい場合は、把持部材の押し込み量を大きくするタイヤ加硫機であり、前記中心機構が、内側中心軸を外側中心軸に内挿するとともに外側中心軸から上方に突出させた二重管構造であり、それぞれの中心軸がタイヤ軸方向の移動量を制御可能に構成され、それぞれの中心軸の外周面に円盤状の支持盤を取り付け、内側中心軸に取り付けた上側の支持盤の上面に前記一対の把持部材の一方の把持部材を構成する複数の円弧状の分割体を配置して、内側中心軸に沿ってタイヤ軸方向に移動する駆動部材と、それぞれの分割体とをリンク部材を介して連結し、駆動部材の移動によりそれぞれの分割体を、タイヤ径方向に移動させて拡張時には環状の一方の把持部材を形成するように構成し、外側中心軸に取り付けた下側の支持盤の下面に前記一対の把持部材の他方の把持部材を構成する複数の円弧状の分割体を配置して、外側中心軸に沿ってタイヤ軸方向に移動する駆動部材と、それぞれの分割体とをリンク部材を介して連結し、駆動部材の移動によりそれぞれの分割体を、タイヤ径方向に移動させて拡張時には環状の他方の把持部材を形成するように構成し、前記内側中心軸および外側中心軸をタイヤ軸方向に移動させて、上側の支持盤と下側の支持盤との間隔を拡大することにより、環状のそれぞれの把持部材をそれぞれのタイヤビード部に押し付ける構成にしたことを特徴とするものである。
【０００７】
また、上記目的を達成するための本発明のタイヤ加硫方法は、上記タイヤ加硫機を使用し、金型内にグリーンタイヤを挿入し、タイヤビード部のヒール側にテーパー面を成形し、該タイヤビード部のトウ側に円筒面を成形した状態でグリーンタイヤを加硫することを特徴とするものである。
【０００８】
本発明では、タイヤ加硫機をブラダーレス構造とし、ビードリングと把持部材とをタイヤ軸方向に延びる円筒状の摺動面に沿って互いに摺動自在に構成し、ビードリングに対する把持部材の押し込み量をタイヤビード部の体積に応じて変更自在にしたことにより、従来のブラダーレス構造を有するタイヤ加硫機では一義的に決定していたビード部の断面積をグリーンタイヤの状態に応じて柔軟に変更することを可能にし、その結果、ビード形状の再現性を高めることができる。なお、把持部材の押し込み量は空気圧や油圧等の圧力に基づいて容易に制御することができる。
【０００９】
本発明において、ビードリングの非摺動面がタイヤビード部のヒール側にテーパー面を成形し、ビードリング及び把持部材のいずれか一方の摺動面がタイヤビード部のトウ側に円筒面を成形する。特に、加硫機下側では、ビードリングの非摺動面がタイヤビード部のヒール側にテーパー面を成形し、ビードリングの摺動面がタイヤビード部のトウ側に円筒面を成形する一方で、加硫機上側では、ビードリングの非摺動面がタイヤビード部のヒール側にテーパー面を成形し、把持部材の摺動面がタイヤビード部のトウ側に円筒面を成形する構成にすれば、グリーンタイヤのセンタリングを良好に行うことができる。
【００１０】
タイヤビード部のトウ側に円筒面を形成するに際し、円筒面のタイヤ軸方向の長さを３〜１０ｍｍに設定することが好ましい。また、タイヤビード部の円筒面のタイヤ軸方向に対する角度は０°にし、テーパー面のタイヤ軸方向に対する立ち上がり角度は５〜２５°することが好ましい。更に、タイヤビード部の円筒面の内径をタイヤ規格に定められたリム径の基準値以下に設定し、該リム径の基準値と円筒面の内径との差を８ｍｍ以下にすることが好ましい。タイヤビード部の円筒面及びテーパー面の寸法を上記の如く設定することにより、ビード形状の再現性を向上しながら加硫後のタイヤ性能を保障することができる。なお、リム径の基準値としては、ＪＡＴＭＡイヤーブック（２０００年度版）に定められた基準値を用いれば良い。
【００１１】
グリーンタイヤ及び加硫タイヤと把持部材との干渉を回避するために、把持部材を複数の分割片から構成し、中心機構が把持部材を複数の分割片に分解した状態でタイヤビード部の最小径より内側に収納することが好ましい。
【００１２】
【発明の実施の形態】
以下、本発明の構成について添付の図面を参照して詳細に説明する。
【００１３】
図１〜図９は本発明の実施形態からなるタイヤ加硫機について説明するものである。図６に示すように、本発明のタイヤ加硫機は、グリーンタイヤＴを収容する金型として、タイヤサイド部を成形する下側プレート１及び上側プレート２と、タイヤビード部を成形する下側ビードリング３及び上側ビードリング４と、タイヤトレッド部を成形する複数のセクター５とを備えている。ビードリング３，４はそれぞれ下側プレート１及び上側プレート２に固定されている。上側プレート２はタイヤ軸方向（上下方向）に開閉し、複数のセクター５はそれぞれタイヤ径方向（水平方向）に開閉するようになっている。
【００１４】
金型の中心位置には、タイヤ軸方向に延長する二重管構造の中心軸７ａ，７ｂを備えた中心機構６が設けられている。これら中心軸７ａ，７ｂはタイヤ軸方向の移動量を制御可能に構成されている。中心軸７ａ，７ｂの外周面にはそれぞれ円盤状の支持盤８ａ，８ｂが取り付けられ、これら支持盤８ａ，８ｂに放射状に延びる複数のレール９ａ，９ｂが形成されている。レール９ａ，９ｂにはそれぞれ把持部材１０ａ，１０ｂを構成する複数の円弧状の分割片１１ａ，１１ｂが摺動自在に設けられている。これら分割片１１ａ，１１ｂはそれぞれリンク部材１２ａ，１２ｂを介して駆動部材１３ａ，１３ｂに連結されている。そのため、駆動部材１３ａ，１３ｂを中心軸７ａ，７ｂに沿って移動させることにより、分割片１１ａ，１１ｂがタイヤ径方向に移動する。
【００１５】
図９に示すように、複数の円弧状の分割片１１ａは、拡張時に環状の把持部材１０ａを形成し、収縮時にはタイヤビード部Ｂの最小径より内側に収納される。上記収納形態を実施にするには、隣り合う分割片１１ａ，１１ａについてリンク部材１２ａの長さを異ならせ、収縮時におけるタイヤ径方向の位置を互いに異ならせるようにすれば良い。また、加硫機上側の把持部材１０ｂについても、上記と同様のリンク機構を形成すれば良い。これにより、中心機構６の把持部材１０ａ，１０ｂがグリーンタイヤＴの投入時や加硫タイヤの搬出時に障害になることを回避できる。また、グリーンタイヤＴ内で環状に形成された把持部材１０ａ，１０ｂは、中心軸７ａ，７ｂの操作によりグリーンタイヤＴの一対のタイヤビード部Ｂ，Ｂをそれぞれビードリング３，４に対して抑えつける。
【００１６】
図７はビードリングと把持部材を拡大して示すものであり、図８はタイヤビード部を拡大して示すものである。但し、図７及び図８では、図面の縦方向をタイヤ径方向とし、図面の横方向をタイヤ軸方向としている。
【００１７】
図７（ａ）に示すように、下側ビードリング３はタイヤ軸方向に対して傾斜する非摺動面Ｘ₁と、タイヤ径方向外側に面してタイヤ軸方向に対して０°となる摺動面Ｙ₁とを備えている。一方、把持部材１０ａはタイヤ径方向に延びる非摺動面Ｘ₂と、タイヤ径方向内側に面してタイヤ軸方向に対して０°となる摺動面Ｙ₂とを備えている。そのため、加硫機下側では、ビードリング３のテーパー状の非摺動面Ｘ₁がタイヤビード部Ｂのヒール側にテーパー面Ｓ₁を成形し、ビードリング３の円筒状の摺動面Ｙ₁がタイヤビード部Ｂのトウ側に円筒面Ｓ₂を成形する。
【００１８】
図７（ｂ）に示すように、上側ビードリング４はタイヤ軸方向に対して傾斜する非摺動面Ｘ₃と、タイヤ径方向内側に面してタイヤ軸方向に対して０°となる摺動面Ｙ₃とを備えている。一方、把持部材１０ｂはタイヤ径方向に延びる非摺動面Ｘ₄と、タイヤ径方向外側に面してタイヤ軸方向に対して０°となる摺動面Ｙ₄とを備えている。そのため、加硫機上側では、ビードリング４のテーパー状の非摺動面Ｘ₃がタイヤビード部Ｂのヒール側にテーパー面Ｓ₁を成形し、把持部材１０ｂの円筒状の摺動面Ｙ₄がタイヤビード部Ｂのトウ側に円筒面Ｓ₂を成形する。
【００１９】
次に、上述したタイヤ加硫機を用いて空気入りタイヤを加硫する方法について説明する。先ず、図１に示すように、グリーンタイヤＴを搬送具１４により搬送し、金型を開けた状態でグリーンタイヤＴを下側プレート１の上にセットする。このとき、中心機構６は把持部材１０ａ，１０ｂを縮径状態にし、かつ把持部材１０ａ，１０ｂを下側に寄せた状態で保持する。グリーンタイヤＴのセット後、図２に示すように、複数のセクター５をグリーンタイヤＴの外周側に配置するように移動させる。
【００２０】
次に、図３に示すように、中心機構６の駆動部材１３ａ，１３ｂを中心軸７ａ，７ｂに沿って移動させることにより、分割片１１ａ，１１ｂをタイヤ径方向外側に拡張して環状の把持部材１０ａ，１０ｂを形成する。次いで、図４に示すように、上側プレート２をグリーンタイヤＴの上方に配置するように移動させる一方で、中心軸７ａ，７ｂをタイヤ軸方向に沿って移動させて中心機構６のベース幅を拡大することにより、把持部材１０ａ，１０ｂをそれぞれタイヤビード部Ｂ，Ｂに押し付ける。
【００２１】
このとき、下側のタイヤビード部Ｂは下側ビードリング３によってセンタリングされ、上側のタイヤビード部Ｂは上側の把持部材１０ｂによってセンタリングされる。即ち、加硫機下側のビードリング３にはタイヤ径方向外側に面した円筒状の摺動面Ｙ₁を設け、加硫機上側の把持部材１０ｂにはタイヤ径方向外側に面した円筒状の摺動面Ｙ₄を設けているので、グリーンタイヤＴのセンタリングを良好に行うことができる（図７参照）。
【００２２】
次に、図５に示すように、複数のセクター５を更にタイヤ径方向内側に移動させると共に、上側プレート２を更に下方に移動させて金型を閉める。そして、図６に示すように、グリーンタイヤＴに内圧Ｐ₁を負荷すると共に、把持部材１０ａ，１０ｂに対してタイヤ軸方向の押し込み圧Ｐ₂を負荷し、その状態でグリーンタイヤＴを加硫する。このとき、ビードリング３，４に対する把持部材１０ａ，１０ｂの押し込み量をグリーンタイヤＴにおけるビード部Ｂの体積に応じて適宜設定する。即ち、タイヤビード部Ｂのボリュームが大きいときには押し込み量を少なくし、ボリュームが小さいときには押し込み量を大きくする。このようにしてビードリング３，４及び把持部材１０ａ，１０ｂで規定されるタイヤビード部Ｂの断面積をグリーンタイヤＴの状態に応じて柔軟に変更することにより、ビード形状の再現性を高めることができる。
【００２３】
把持部材１０ａ，１０ｂの押し込み量は、把持部材１０ａ，１０ｂに負荷する押し込み圧Ｐ₂に基づいて設定することができる。この押し込み圧Ｐ₂は空気圧や油圧等の圧力を利用して容易に制御することが可能である。上記押し込み圧Ｐ₂を適切に制御すれば、グリーンタイヤＴの内面に形成される把持界面の段差を最小限に抑制することができる。
【００２４】
上述のようにして加硫された空気入りタイヤにおいては、タイヤビード部Ｂのヒール側にテーパー面Ｓ₁が成形され、タイヤビード部Ｂのトウ側に円筒面Ｓ₂が成形される（図８参照）。
【００２５】
図８に示すように、タイヤビード部Ｂのトウ側に円筒面Ｓ₂を設けるに際し、円筒面Ｓ₂のタイヤ軸方向の長さＬが３〜１０ｍｍになるようにビードリング３，４と把持部材１０ａ，１０ｂの寸法及び位置関係を設定すると良い。この長さＬが３ｍｍ未満であるとビードリング３，４に対する把持部材１０ａ，１０ｂの押し込み量を十分に確保することが困難になり、逆に１０ｍｍを超えるとタイヤの嵌合性が低下する。把持部材１０ａ，１０ｂをビードリング３，４に対して押し込んでいくと最終的には機械的な当て止めになるが、円筒面Ｓ₂長さＬを上記範囲に設定しておけば機械的な当て止めに至ることはない。
【００２６】
また、タイヤビード部Ｂの円筒面Ｓ₂のタイヤ軸方向に対する角度は０°にし、テーパー面Ｓ₁のタイヤ軸方向に対する立ち上がり角度θは５〜２５°すると良い。円筒面Ｓ₂のタイヤ軸方向に対する角度が実質的に０°でないとビードリングと把持部材とが摺動する際に界面にゴムが流入する恐れがある。また、テーパー面Ｓ₁の立ち上がり角度θが上記範囲から外れるとタイヤの嵌合性が低下する。
【００２７】
更に、タイヤビード部Ｂの円筒面Ｓ₂の内径Ｄはタイヤ規格に定められたリム径の基準値以下に設定し、該リム径の基準値と円筒面の内径Ｄとの差を８ｍｍ以下にすると良い。この内径Ｄがリム径の基準値を超えるとタイヤの嵌合性が低下し、逆に内径Ｄがリム径の基準値に比べて８ｍｍを超えて小さくなるとリム組み作業が困難になる。
【００２８】
【発明の効果】
以上説明したように本発明によれば、グリーンタイヤを収容する金型の中心位置に、一対のタイヤビード部をそれぞれ金型のビードリングに対して抑えつける一対の把持部材をタイヤ径方向及びタイヤ軸方向に変位させる中心機構を配設し、ビードリングと把持部材とをタイヤ軸方向に延びる円筒状の摺動面に沿って互いに摺動自在に構成し、ビードリングに対する把持部材の押し込み量を、把持部材に負荷するタイヤ軸方向の圧力に基づいて制御することにより、前記タイヤビード部の体積に応じて変更自在にして、タイヤビード部の体積が大きい場合は、把持部材の押し込み量を少なくし、タイヤビード部の体積が小さい場合は、把持部材の押し込み量を大きくするタイヤ加硫機を用いることにより、ブラダーレス構造を備えながら、ビード形状の再現性を高めることができる。
【００２９】
従って、ブラダーに起因する生産性の低下や加硫故障、熱効率の低下、更にはブラダー製造コストの負担を受けることなく、良好なビード形状を有する高品質の空気入りタイヤを提供することが可能になる。
【図面の簡単な説明】
【図１】本発明の実施形態からなるタイヤ加硫機を用いた加硫方法の第１工程を示す断面図である。
【図２】本発明の実施形態からなるタイヤ加硫機を用いた加硫方法の第２工程を示す断面図である。
【図３】本発明の実施形態からなるタイヤ加硫機を用いた加硫方法の第３工程を示す断面図である。
【図４】本発明の実施形態からなるタイヤ加硫機を用いた加硫方法の第４工程を示す断面図である。
【図５】本発明の実施形態からなるタイヤ加硫機を用いた加硫方法の第５工程を示す断面図である。
【図６】本発明の実施形態からなるタイヤ加硫機を用いた加硫方法の第６工程を示す断面図である。
【図７】（ａ），（ｂ）はそれぞれ本発明の実施形態からなるタイヤ加硫機の要部を示す断面図である。
【図８】本発明の実施形態からなるタイヤ加硫機で成形されるタイヤビード部を示す断面図である。
【図９】本発明の実施形態からなるタイヤ加硫機の要部を示す平面図である。
【符号の説明】
１下側プレート
２上側プレート
３下側ビードリング
４上側ビードリング
５セクター
６中心機構
７ａ，７ｂ中心軸
８ａ，８ｂ支持盤
９ａ，９ｂレール
１０ａ，１０ｂ把持部材
１１ａ，１１ｂ分割片
１２ａ，１２ｂリンク部材
１３ａ，１３ｂ駆動部材
１４搬送具
Ｘ₁〜Ｘ₄ 非摺動面
Ｙ₁〜Ｙ₄ 摺動面
Ｓ₁ テーパー面
Ｓ₂ 円筒面
Ｌ円筒面の長さ
Ｄ円筒面の内径
θ テーパー面の立ち上がり角度
Ｔグリーンタイヤ
Ｂタイヤビード部[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a vulcanizer and a vulcanization method for vulcanizing a pneumatic tire. More specifically, the present invention relates to a tire vulcanizer and a tire vulcanizer having a bladderless structure and improving bead shape reproducibility. It relates to a sulfur process.
[0002]
[Prior art]
In normal tire vulcanization, a rubber bag called a bladder is inserted inside a green tire (unvulcanized tire) that has been put into a vulcanizer, and steam or hot water is introduced into the bladder as a heating medium. In this state, the tire is vulcanized. However, the conventional vulcanization method using a bladder not only requires a great amount of man-hours for the production of the bladder and the setting to the vulcanizer, but also increases energy loss and takes time to vulcanize, improving tire production efficiency. There are many obstacles to cost reduction.
[0003]
In order to eliminate the inconvenience in the vulcanization method using the bladder, a bladderless vulcanizer is proposed in, for example, Japanese Patent Application Laid-Open Nos. 2-212105 and 6-71652. These bladderless vulcanizers are provided with mechanical means for pressing the tire bead portion instead of the rubber bladder.
[0004]
However, in the bladderless vulcanizer, the mechanical means for pressing the tire bead portion cannot be flexibly displaced according to the volume of the bead portion of the green tire, so when the volume is large, the bead portion is crushed and the volume is reduced. When it is small, there is a problem that voids remain, and as a result, the reproducibility of the bead shape is lowered.
[0005]
[Problems to be solved by the invention]
An object of the present invention is to provide a tire vulcanizer and a tire vulcanization method that have a bladderless structure and can improve the reproducibility of a bead shape.
[0006]
[Means for Solving the Problems]
In order to achieve the above object, a tire vulcanizer according to the present invention includes a pair of gripping members that respectively hold a pair of tire bead portions against the bead ring of the mold at a center position of a mold that houses a green tire. A central mechanism that displaces the tire in the tire radial direction and the tire axial direction, and the bead ring and the gripping member are configured to be slidable with each other along a cylindrical sliding surface extending in the tire axial direction, By controlling the pushing amount of the gripping member against the bead ring based on the pressure in the tire axial direction applied to the gripping member, the volume of the tire bead portion can be increased according to the volume of the tire bead portion. If, to reduce the pushing amount of the gripping member, when the volume of the tire bead portion is small, a tire vulcanizer to increase the pushing amount of the gripping member, said central unit Is a double tube structure in which the inner central axis is inserted into the outer central axis and protrudes upward from the outer central axis, and each central axis is configured to be able to control the amount of movement in the tire axial direction. A disc-shaped support plate is attached to the outer peripheral surface of the central shaft, and a plurality of arc-shaped divided bodies constituting one grip member of the pair of grip members are arranged on the upper surface of the upper support plate attached to the inner central shaft. The drive member that moves in the tire axial direction along the inner central axis and the respective divided bodies are connected via a link member, and the respective divided bodies are moved in the tire radial direction by the movement of the drive member. A plurality of arc-shaped divided bodies that are formed so as to form one annular gripping member at the time of expansion, and constitute the other gripping member of the pair of gripping members on the lower surface of the lower support plate attached to the outer central shaft Place the outer center The drive members that move in the tire axial direction along the tires and the respective divided bodies are connected via link members, and each divided body is moved in the tire radial direction by the movement of the drive member, and the other ring that is annular when expanded. Each of the annular members is formed by moving the inner central shaft and the outer central shaft in the tire axial direction to increase the distance between the upper support plate and the lower support plate. The gripping member is pressed against each tire bead portion .
[0007]
In addition, the tire vulcanization method of the present invention for achieving the above object uses the tire vulcanizer, inserts a green tire into a mold, and forms a tapered surface on the heel side of the tire bead portion. The green tire is vulcanized with a cylindrical surface formed on the toe side of the tire bead portion.
[0008]
In the present invention, the tire vulcanizer has a bladderless structure, and the bead ring and the gripping member are configured to be slidable with each other along a cylindrical sliding surface extending in the tire axial direction. Can be changed according to the volume of the tire bead, and the cross-sectional area of the bead, which has been uniquely determined in a conventional tire vulcanizer with a bladderless structure, can be flexibly changed according to the state of the green tire. As a result, the reproducibility of the bead shape can be improved. The pushing amount of the gripping member can be easily controlled based on pressure such as air pressure or hydraulic pressure.
[0009]
In the present invention, the non-sliding surface of the bead ring forms a tapered surface on the heel side of the tire bead portion, and one of the sliding surfaces of the bead ring and the gripping member forms a cylindrical surface on the toe side of the tire bead portion. To do. In particular, on the lower side of the vulcanizer, the non-sliding surface of the bead ring forms a tapered surface on the heel side of the tire bead portion, and the sliding surface of the bead ring forms a cylindrical surface on the toe side of the tire bead portion. On the upper side of the vulcanizer, the non-sliding surface of the bead ring forms a tapered surface on the heel side of the tire bead portion, and the sliding surface of the gripping member forms a cylindrical surface on the toe side of the tire bead portion. Then, the centering of the green tire can be performed satisfactorily.
[0010]
When forming the cylindrical surface on the toe side of the tire bead portion, it is preferable to set the length of the cylindrical surface in the tire axial direction to 3 to 10 mm. The angle of the cylindrical surface of the tire bead portion with respect to the tire axial direction is preferably 0 °, and the rising angle of the tapered surface with respect to the tire axial direction is preferably 5 to 25 °. Further, it is preferable that the inner diameter of the cylindrical surface of the tire bead portion is set to be equal to or smaller than the reference value of the rim diameter defined in the tire standard, and the difference between the reference value of the rim diameter and the inner diameter of the cylindrical surface is set to 8 mm or less. By setting the dimensions of the cylindrical surface and the tapered surface of the tire bead portion as described above, the tire performance after vulcanization can be ensured while improving the reproducibility of the bead shape. As the rim diameter reference value, the reference value defined in the JATMA Yearbook (2000 version) may be used.
[0011]
In order to avoid interference between the green tire and vulcanized tire and the gripping member, the gripping member is composed of a plurality of divided pieces, and the minimum diameter of the tire bead portion in a state where the central mechanism disassembles the gripping member into the plurality of divided pieces. It is preferable to store it inside.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the configuration of the present invention will be described in detail with reference to the accompanying drawings.
[0013]
FIGS. 1-9 demonstrates the tire vulcanizer which consists of embodiment of this invention. As shown in FIG. 6, the tire vulcanizer according to the present invention includes a lower plate 1 and an upper plate 2 that form a tire side portion as a mold for housing a green tire T, and a lower side that forms a tire bead portion. A bead ring 3 and an upper bead ring 4 and a plurality of sectors 5 for forming a tire tread portion are provided. The bead rings 3 and 4 are fixed to the lower plate 1 and the upper plate 2, respectively. The upper plate 2 opens and closes in the tire axial direction (vertical direction), and the plurality of sectors 5 open and close in the tire radial direction (horizontal direction).
[0014]
At the center position of the mold, there is provided a center mechanism 6 having center axes 7a and 7b having a double pipe structure extending in the tire axial direction. These central shafts 7a and 7b are configured to be able to control the amount of movement in the tire axial direction. Disc-shaped support plates 8a and 8b are attached to the outer peripheral surfaces of the central shafts 7a and 7b, respectively, and a plurality of rails 9a and 9b extending radially are formed on the support plates 8a and 8b. The rails 9a and 9b are provided with a plurality of arc-shaped divided pieces 11a and 11b that slidably form the gripping members 10a and 10b, respectively. These divided pieces 11a and 11b are connected to driving members 13a and 13b via link members 12a and 12b, respectively. Therefore, by moving the drive members 13a and 13b along the central axes 7a and 7b, the divided pieces 11a and 11b move in the tire radial direction.
[0015]
As shown in FIG. 9, the plurality of arc-shaped divided pieces 11a form an annular gripping member 10a when expanded, and are housed inside the minimum diameter of the tire bead portion B when contracted. In order to implement the storage mode, the length of the link member 12a may be made different between the adjacent divided pieces 11a and 11a, and the positions in the tire radial direction at the time of contraction may be made different from each other. Moreover, what is necessary is just to form the link mechanism similar to the above also about the holding member 10b of a vulcanizer upper side. Thereby, it can avoid that the holding members 10a and 10b of the center mechanism 6 become an obstacle when the green tire T is inserted or when the vulcanized tire is carried out. Further, the gripping members 10a and 10b formed in an annular shape in the green tire T hold the pair of tire bead portions B and B of the green tire T against the bead rings 3 and 4 by operating the central shafts 7a and 7b, respectively. Put on.
[0016]
FIG. 7 is an enlarged view of the bead ring and the gripping member, and FIG. 8 is an enlarged view of the tire bead portion. However, in FIG.7 and FIG.8, the vertical direction of drawing is made into the tire radial direction, and the horizontal direction of drawing is made into the tire axial direction.
[0017]
As shown in FIG. 7A, the lower bead ring 3 has a non-sliding surface X ₁ that is inclined with respect to the tire axial direction, and faces the outer side in the tire radial direction and is 0 ° with respect to the tire axial direction. and a sliding surface Y _1. On the other hand, the gripping member 10a is provided with a non-sliding surface X ₂ extending in the tire radial direction, and a sliding surface Y ₂ which becomes 0 ° with respect to the tire axial direction facing the inner side in the tire radial direction. Therefore, on the lower side of the vulcanizer, the tapered non-sliding surface X ₁ of the bead ring 3 forms a tapered surface S ₁ on the heel side of the tire bead portion B, and the cylindrical sliding surface Y of the bead ring 3 is formed. ₁ forms the cylindrical surface S ₂ on the toe side of the tire bead portion B.
[0018]
As shown in FIG. 7 (b), and the non-sliding surface X ₃ upper bead ring 4 is inclined to the tire axial direction and 0 ° with respect to the tire axial direction facing the inner side in the tire radial direction sliding and a sliding surface Y _3. On the other hand, the gripping member 10b is provided with a non-sliding surface X ₄ extending in the tire radial direction, and a sliding surface Y ₄ which is 0 ° with respect to the tire axial direction facing the outer side in the tire radial direction. Therefore, on the upper side of the vulcanizer, the tapered non-sliding surface X ₃ of the bead ring 4 forms a tapered surface S ₁ on the heel side of the tire bead portion B, and the cylindrical sliding surface Y _{4 of the} gripping member 10b. The cylindrical surface S ₂ is formed on the toe side of the tire bead portion B.
[0019]
Next, a method for vulcanizing a pneumatic tire using the above-described tire vulcanizer will be described. First, as shown in FIG. 1, the green tire T is transported by the transport tool 14, and the green tire T is set on the lower plate 1 with the mold opened. At this time, the center mechanism 6 holds the gripping members 10a and 10b in a reduced diameter state and keeps the gripping members 10a and 10b close to the lower side. After the green tire T is set, the plurality of sectors 5 are moved so as to be arranged on the outer peripheral side of the green tire T as shown in FIG.
[0020]
Next, as shown in FIG. 3, by moving the drive members 13a and 13b of the central mechanism 6 along the central axes 7a and 7b, the divided pieces 11a and 11b are expanded outward in the tire radial direction, and are held in an annular shape. Members 10a and 10b are formed. Next, as shown in FIG. 4, the upper plate 2 is moved so as to be disposed above the green tire T, while the central shafts 7 a and 7 b are moved along the tire axial direction to increase the base width of the central mechanism 6. By enlarging, the gripping members 10a and 10b are pressed against the tire bead portions B and B, respectively.
[0021]
At this time, the lower tire bead portion B is centered by the lower bead ring 3, and the upper tire bead portion B is centered by the upper gripping member 10b. That is, pressing the vulcanizer lower bead ring 3 provided a cylindrical sliding surface Y ₁ facing outward in the tire radial direction, a cylindrical facing outward in the tire radial direction in the vulcanizer above the gripping member 10b since is provided a sliding surface Y _4, it can be performed well centering of the green tire T (see FIG. 7).
[0022]
Next, as shown in FIG. 5, the plurality of sectors 5 are further moved inward in the tire radial direction, and the upper plate 2 is further moved downward to close the mold. Then, as shown in FIG. 6, while applying an internal pressure P ₁ to the green tire T, a pressing pressure P ₂ in the tire axial direction is applied to the gripping members 10a and 10b, and the green tire T is vulcanized in this state. To do. At this time, the pressing amount of the gripping members 10a and 10b with respect to the bead rings 3 and 4 is appropriately set according to the volume of the bead portion B in the green tire T. That is, when the volume of the tire bead portion B is large, the pushing amount is decreased, and when the volume is small, the pushing amount is increased. Thus, the reproducibility of the bead shape is enhanced by flexibly changing the cross-sectional area of the tire bead portion B defined by the bead rings 3 and 4 and the gripping members 10a and 10b according to the state of the green tire T. Can do.
[0023]
Push-in amount of the gripping member 10a, 10b may be set based on the pushing pressure P ₂ which load the gripping member 10a, 10b. The pushing pressure P ₂ is able to easily control by using the pressure of such a pneumatic or hydraulic pressure. By appropriately controlling the indentation pressure P ₂ , the level difference of the grip interface formed on the inner surface of the green tire T can be suppressed to the minimum.
[0024]
In the pneumatic tire vulcanized as described above, the tapered surface S ₁ is formed on the heel side of the tire bead portion B, and the cylindrical surface S ₂ is formed on the toe side of the tire bead portion B (FIG. 8). reference).
[0025]
As shown in FIG. 8, when the cylindrical surface S ₂ is provided on the toe side of the tire bead portion B, the bead rings 3 and 4 are gripped so that the length L in the tire axial direction of the cylindrical surface S ₂ is 3 to 10 mm. The dimensions and positional relationship of the members 10a and 10b may be set. If the length L is less than 3 mm, it becomes difficult to ensure a sufficient amount of pressing of the gripping members 10a and 10b with respect to the bead rings 3 and 4. Conversely, if the length L exceeds 10 mm, the fitting property of the tire decreases. Gripping member 10a, becomes a mechanical stoppers are 10b to push in going the final against bead rings 3 and 4, the mechanical if the cylindrical surface S ₂ length L by setting the above range There is no end to it.
[0026]
The angle with respect to the tire axial direction of the cylindrical surface S ₂ of the tire bead portion B to 0 °, rising angle θ with respect to the tire axial direction of the tapered surface S ₁ is 5 to 25 ° Then good. Angle with respect to the tire axial direction of the cylindrical surface S ₂ is likely to have a grip substantially 0 ° not equal bead ring member rubber flows into the interface when the slide. Further, when the rising angle θ of the tapered surface S ₁ is out of the above range, the fitting property of the tire is deteriorated.
[0027]
Furthermore, the inner diameter D of the cylindrical surface S ₂ of the tire bead portion B is set equal to or less than the reference value of rim diameter defined in the tire standard, the difference between the inner diameter D of the reference value and the cylindrical surface of the rim diameter 8mm or less Good. When the inner diameter D exceeds the rim diameter reference value, the fitting property of the tire is lowered, and conversely, when the inner diameter D becomes smaller than the rim diameter reference value by more than 8 mm, the rim assembling work becomes difficult.
[0028]
【The invention's effect】
As described above, according to the present invention, the pair of gripping members that respectively hold the pair of tire bead portions against the bead ring of the mold at the center position of the mold that accommodates the green tire are provided in the tire radial direction and the tire. A central mechanism for axial displacement is provided, and the bead ring and the gripping member are configured to be slidable with each other along a cylindrical sliding surface extending in the tire axial direction. By controlling based on the pressure in the tire axial direction applied to the gripping member, it can be changed according to the volume of the tire bead portion, and when the volume of the tire bead portion is large, the pushing amount of the gripping member is reduced. and, when the volume of the tire bead portion is small, by using a tire vulcanizer to increase the pushing amount of the gripping member, while including Buradaresu structure, bi- It is possible to improve the reproducibility of the de shape.
[0029]
Accordingly, it is possible to provide a high-quality pneumatic tire having a good bead shape without suffering from a decrease in productivity, a vulcanization failure, a decrease in thermal efficiency, and a burden of manufacturing costs of the bladder due to the bladder. Become.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view showing a first step of a vulcanization method using a tire vulcanizer according to an embodiment of the present invention.
FIG. 2 is a cross-sectional view showing a second step of the vulcanization method using the tire vulcanizer according to the embodiment of the present invention.
FIG. 3 is a cross-sectional view showing a third step of a vulcanization method using a tire vulcanizer according to an embodiment of the present invention.
FIG. 4 is a sectional view showing a fourth step of a vulcanization method using a tire vulcanizer according to an embodiment of the present invention.
FIG. 5 is a cross-sectional view showing a fifth step of the vulcanizing method using the tire vulcanizer according to the embodiment of the present invention.
FIG. 6 is a sectional view showing a sixth step of the vulcanizing method using the tire vulcanizer according to the embodiment of the present invention.
FIGS. 7A and 7B are cross-sectional views showing a main part of a tire vulcanizer according to an embodiment of the present invention, respectively.
FIG. 8 is a cross-sectional view showing a tire bead portion formed by a tire vulcanizer according to an embodiment of the present invention.
FIG. 9 is a plan view showing a main part of the tire vulcanizer according to the embodiment of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Lower plate 2 Upper plate 3 Lower bead ring 4 Upper bead ring 5 Sector 6 Center mechanism 7a, 7b Center shaft 8a, 8b Supporting board 9a, 9b Rail 10a, 10b Grasp member 11a, 11b Split piece 12a, 12b Link member 13a, the rising angle of 13b drive member 14 conveying device X ₁ to X ₄ non sliding surface Y ₁ to Y ₄ sliding surface S ₁ tapered surface S inner diameter θ tapered surface length D cylindrical surface of the _second cylindrical surface L cylindrical surface T Green tire B Tire bead part

Claims

A central mechanism that displaces a pair of gripping members that hold the pair of tire bead portions against the bead ring of the mold in the tire radial direction and the tire axial direction is disposed at the center position of the mold for housing the green tire. The bead ring and the gripping member are configured to be slidable along a cylindrical sliding surface extending in the tire axial direction, and the pressing amount of the gripping member against the bead ring is loaded on the gripping member. By controlling based on the pressure in the tire axial direction, it can be changed according to the volume of the tire bead portion, and when the volume of the tire bead portion is large, the pushing amount of the gripping member is reduced, and the tire bead portion when the volume is small, a tire vulcanizer to increase the pushing amount of the gripping member, the outer the central mechanism, with interpolate inner center axis to the outer central axis Double pipe structure projecting upward from the central axis, each central axis is configured to be able to control the amount of movement in the tire axial direction, a disk-shaped support disk is attached to the outer peripheral surface of each central axis, and the inside A drive that moves in the tire axial direction along the inner central axis by arranging a plurality of arcuate segments constituting one gripping member of the pair of gripping members on the upper surface of the upper support plate attached to the central axis The member and each divided body are connected via a link member, and each divided body is moved in the tire radial direction by the movement of the drive member to form one annular gripping member at the time of expansion. A plurality of arc-shaped segments constituting the other gripping member of the pair of gripping members are disposed on the lower surface of the lower support plate attached to the outer center shaft, and are arranged along the outer center axis in the tire axial direction. Moving drive member and it The divided members are connected to each other via a link member, and each divided member is moved in the tire radial direction by movement of the driving member to form the other annular gripping member at the time of expansion. By moving the central axis and the outer central axis in the tire axial direction to increase the distance between the upper support plate and the lower support plate, the annular gripping members are pressed against the respective tire bead portions. Tire vulcanizer .

A central mechanism that displaces a pair of gripping members that hold the pair of tire bead portions against the bead ring of the mold in the tire radial direction and the tire axial direction is disposed at the center position of the mold for housing the green tire. The bead ring and the gripping member are configured to be slidable with each other along a cylindrical sliding surface extending in the tire axial direction, and the central mechanism interpolates the inner central axis with the outer central axis. It is a double tube structure that protrudes upward from the outer central axis, each central axis is configured to be able to control the amount of movement in the tire axial direction, and a disk-shaped support disk is attached to the outer peripheral surface of each central axis, A plurality of arc-shaped segments constituting one gripping member of the pair of gripping members are arranged on the upper surface of the upper support plate attached to the inner central shaft and moved in the tire axial direction along the inner central shaft. Drive part And each divided body is connected via a link member, and each divided body is moved in the tire radial direction by movement of the drive member to form one annular gripping member at the time of expansion, A plurality of arc-shaped segments constituting the other gripping member of the pair of gripping members are arranged on the lower surface of the lower support plate attached to the outer center shaft, and moved in the tire axial direction along the outer center shaft The drive member to be connected to each divided body via a link member, and by moving the drive member, each divided body is moved in the tire radial direction to form the other annular gripping member at the time of expansion. The inner center axis and the outer center axis are moved in the tire axial direction to increase the distance between the upper support plate and the lower support plate, thereby allowing each of the annular gripping members to be connected to each tire bead. As it pressed against the de section, the push-in amount of the gripping member with respect to the bead ring, by controlling on the basis of the pressure in the tire axial direction to the load on the gripping member, and freely changed according to the volume of the tire bead portion When the tire bead volume is large, use a tire vulcanizer that reduces the pushing amount of the gripping member, and when the tire bead volume is small, increase the pushing amount of the gripping member. A tire vulcanizing method in which a green tire is inserted into the tire bead, a tapered surface is formed on the heel side of the tire bead portion, and the green tire is vulcanized in a state where a cylindrical surface is formed on the toe side of the tire bead portion.