JP3754517B2 - Partially unconstrained laminated rubber bearing - Google Patents

Partially unconstrained laminated rubber bearing Download PDF

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Publication number
JP3754517B2
JP3754517B2 JP929497A JP929497A JP3754517B2 JP 3754517 B2 JP3754517 B2 JP 3754517B2 JP 929497 A JP929497 A JP 929497A JP 929497 A JP929497 A JP 929497A JP 3754517 B2 JP3754517 B2 JP 3754517B2
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Prior art keywords
rubber
bearing
unconstrained
hard plate
rubber layer
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JPH10205165A (en
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藤 元 佐
村 幸 夫 中
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Yokohama Rubber Co Ltd
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Yokohama Rubber Co Ltd
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Description

【0001】
【発明の属する技術分野】
本発明は、構造物の免震等に利用される部分非拘束型積層ゴム支承に関する。
【0002】
【従来の技術】
近年、振動エネルギーの吸収装置、すなわち、防振、除振、免震装置等が急速に普及しつつある。このような吸収装置の一形態として、鋼板とゴム層を交互に積層した免震用積層ゴムが挙げられる。免震用積層ゴムは、鉛直方向には非常に硬い物体として振る舞い、水平方向に対しては単体のゴム塊の場合と同様に大きくずれて、柔らかい物体として振る舞うことから、例えば建物等の支承として用いた場合には、地面の揺れが直接建物等に伝わるのを抑制し、また、橋梁等の支承として用いた場合には、橋梁の地震動による振動を緩和し、共に建物、橋梁等の建造物を保護する。
【0003】
今日、免震用の積層ゴム支承は、鋼板とゴム層の接合面を完全に接着した両面完全接着型ともいえるタイプが標準的である。このタイプの積層ゴム支承は、鋼板とゴム層の接合面の両面が完全に接着されているため安定性に優れるが、ゴム層にかかる水平変位がある限界を越えると、それに伴う水平荷重が急激に増大するいわゆるハードニング現象の効果が大きい。すなわち、積層ゴム支承としての水平剛性が急激に増大し、その結果、建造物の免震効果が十分得られない。また振動減衰性能、すなわちダンピングの効果は一般にあまり高くはない。
このような鋼板とゴム層を完全に接着したタイプの免震用積層ゴム支承の対極に、鋼板とゴム層を完全に非接着にしたタイプ、例えば、鋼板の周りに薄いゴムを加硫接着したものと加硫ゴムシートを完全に非接着で積層する積層ゴム支承(特開平6−50025号公報参照)が提案されている。しかしながら、各層間が建物等の荷重のみで密着させた非接着構造のため、震動が加わった時に、非接着である接合面がずれてゴムが面板端部から外へはみ出してしまう。また、震動により積層ゴム支承上の建造物全体がロッキングを生じると、建造物の片側が浮く状態になってしまい、接合面がはずれてしまう。この鋼板とゴム層を完全に非接着にしたタイプの積層ゴム支承の改良方式として、鋼板とゴム層の外周のみを接着して拘束する積層ゴム支承が提案されている。これらの積層ゴム支承は、製造工程が簡略化できるものの、鉛直剛性やその他の剪断特性等の力学的特性が不安定となり易く、性能面で劣っている。減衰性能、すなわちダンピング効果の上昇が時に発現することもあるが、その現れ方は荷重条件や繰り返しによって安定性を欠いているので、免震システムの設計に生かすことはできない。
【0004】
また、鋼板とゴム層を積層した筒型の拘束体の中空部に、別の構造体として硬質板と粘弾塑性体との積層物を充填し外周を加硫ゴムで被覆した構造の周囲拘束型積層ゴムが提案されている(特開平6−137378号公報参照)。鋼板とゴム層の一部が非接着となっているタイプの支承であるが、支承の外周部と中央部が異なった構造となっており、構造が複雑であり製造工程が複雑である。
【0005】
【発明が解決しようとする課題】
本発明は、上記実情に鑑みてなされたもので、その目的は、両面完全接着型の積層ゴム支承の安定性を維持しながら、同時に剪断剛性が低く、ハードニング現象が抑制され、減衰性能の向上した部分非拘束型積層ゴム支承を提供することである。
【0006】
【課題を解決するための手段】
すなわち、本発明は、ゴム層と硬質板とが交互に積層してなる免震用の積層ゴム支承において、前記ゴム層と前記硬質板の接合面に、接合面積に対して20〜50%の面積で、偏ることなく均一に、複数の互いに離隔した非接着面を有する部分非拘束型積層ゴム支承を提供する。
【0007】
前記非接着面の最大長さは、前記ゴム層1層当たりの厚みの1〜10倍であることが好ましい。
【0008】
さらに、前記非接着面の全部が前記接合面の外周に接していないことが好ましい。
【0009】
【発明の実施の形態】
以下に、本発明についてさらに詳細に説明する。
本発明の部分非拘束型積層ゴム支承(以下、支承と記す)は、特定の部分非拘束パターンを、ゴム層と硬質板との接合面に導入することを特徴とする。
ここで、部分非拘束パターンとは、各々の重心位置が異なる複数の離隔した部分からなる非接着面すなわち非拘束面と、連続した接着面とからなる、非拘束な部分が複数ある非拘束パターンをいう。
【0010】
本発明の非拘束パターンは、以下に記す特徴を持つ。
▲1▼本発明の非拘束パターンは、従来の接着面、すなわちゴム層と硬質板との接合面上に非接着部分のパターンとして形成される。
図1に、ゴム層と硬質板との接合面に非拘束パターンを有する本発明の支承の断面の概念図を示す。図中、ゴム層と硬質板との間の太線は拘束面を、細い線は非拘束面を示す。拘束面では、ゴム層と硬質板の接合面が、例えば、加硫接着等により強固に接着している。一方、非拘束面では、ゴム層と硬質板とが密接はしていても接着はしておらず、相互に摩擦力を働かせながら相対的なすべりが可能である。
図2に、本発明の非拘束パターンの具体例を示す。
【0011】
2)本発明の非拘束パターンは、その合計面積がゴム層と硬質板との接合面積の70%以下である。
元来、積層ゴム支承はゴム弾性により水平方向に振動可能であり、水平方向の固有振動周期を破壊の原因となる地震等の横波の最大振幅成分の振動周期より長くできるので、これにより地震等の振動の速度や加速度を低減して伝える免震機能を持つ。また、長周期でゆれる建物等の震動を、減少させる減衰機能も重要な性能である。ゴム層と硬質板の接合面を完全接着した支承と、ゴム層と硬質板の接合面に部分非拘束パターンを導入した支承とを減衰性能で比較すると、後述の実施例1で作成した部分非拘束パターンを有する支承の等価粘性減衰定数の測定に示すように、大きい揺れ(例えば、剪断歪みが200%以上に達する揺れ)で、部分非拘束パターンを有する支承のほうが向上していることがわかった。
図3に、非拘束パターンの面積比率に対する安定性と減衰性能の変化(等価粘性減衰定数の変化)を概念的にグラフにして示す。グラフの横軸は接合面における非拘束パターンの占める面積、すなわち非拘束パターンの面積比率である。左の縦軸は、積層ゴム支承の安定性、具体的には鉛直方向の引張り剛性の値を、ゴム層と硬質板の接合面が完全に接着している積層ゴム支承における鉛直方向の引張り剛性の値を100%として相対値で示している。右の縦軸は、積層ゴム支承の減衰性能を表す等価粘性減衰定数を示している。積層ゴム支承は、非拘束パターンの面積を変えた以外はすべて同一構造とした。
図3から分かるように、非拘束パターン導入による減衰性能の向上(等価粘性減衰定数の増加)は、ある程度非拘束パターンの面積比率に比例する。しかし、不安定さは、或る敷居値を境に急激に増す(安定性が急激に減る)ことが分かるまた、減衰性能の効果が現れるのは、非拘束パターンの面積比率が20%程度からである。従って、非拘束パターンの面積比率は、20〜50%、好ましくは30〜50%である。
個々の非接着部分の合計は、積層ゴム支承が用いられる建造物、例えば建物と橋梁とでは異なる。すなわち、建物では、地震等の振動を緩衝するため水平方向の剛性は低い方が好ましく、ゴム層と硬質板の接合面の非接着部分は大きい方がよい。橋梁では、上を走る車両からの振動を緩衝するため鉛直方向の剛性は低い必要があるが、水平方向には、橋梁が外れる危険性がないよう剛性をある程度高くする必要がある。このため橋梁では、建物に用いられる積層ゴム支承に比べ、ゴム層と硬質板の接合面の非接着部分は小さい。
【0012】
▲3▼本発明の非拘束パターンは、各々に重心位置が異なる複数の離隔した非接着面から構成されている。
本発明の非拘束パターンは、ゴム層と硬質板の接合面に、好ましくは偏ることなく均一に、複数離隔して配置されている。このような配置により振動を受けた際、接合面に発生するすべりが接合面の特定部分に集中することなく、接合面全体に均一に分散され安定性が高い。従って、本発明の非拘束パターンは、非接着面が1つだけの非拘束パターンは含まない。
非拘束パターンが離隔することなく連続していると、ゴム層と硬質板の接合面に、例えば、水が入った場合、硬質板が特に鉄板等であると、連続して錆びが広がってしまうという問題がある。しかし非拘束パターンが複数、離隔していれば、水がはいっても接合面によってさえぎられ硬質板が錆びる面積を少なく抑えることができる。
このような本発明の非拘束パターンとして、図2に示す非拘束パターン、および図4に示す非拘束パターンを例示することができる。
【0013】
▲4▼本発明の非拘束パターンを構成する各々の非接着部分の最大長さは、ゴム層1層当たりの厚みの1〜10倍が好ましい。
ここで、最大長さとは、例えば、矩形であれば図5に示すように対角線dの長さ、また、非拘束部分が円であれば直径、楕円であれば長軸をいう。
非接着部分がゴム層と硬質板の接合面の中央に大きく開いていると、接合面の周縁部分と中央部分の拘束状態が大きく異なり、この差が違いすぎると、振動エネルギーが加わった際に接合面は破壊される。したがって、一つの接合面に発生する拘束状態が部分により大きく異ならないよう、個々の離隔した非接着部分の大きさをある一定の大きさよりも小さく抑えることが必要である。
本発明の非拘束パターンを構成する各々の非接着部分の最大長さは、ゴム層1層当たりの厚みの1〜10倍、好ましくは3〜8倍である。1未満であると、減衰性能等の効果が現れない。10倍超であると、非接着部分と接着部分との拘束状態に差がありすぎ不安定となる。
【0014】
▲5▼本発明の非拘束パターンを構成する離隔した非接着面の大方あるいは全部はゴム層および硬質板の周縁部分に接さないよう配置するのが好ましい。
具体例を図6に示す。例えば図6では周縁部分に接する非接着面が、合計16個のうち11個あり好ましくない。周縁部分に接する非接着面が多いと、繰り返し変形が加えられたときに、非接着部分のゴムが膨出してしまう。
【0015】
▲6▼本発明の非拘束パターンに方向性はない方が好ましいが、あってもよい。
例えば、建物用の積層ゴム支承では、地震の揺れがくる方向が全方位に渡ると考えられるので、全方位に免震性等の効果があることが必要であり、図4(a)のように非拘束パターンに方向性はない方が好ましい。一方、橋梁のような長尺物では抑制したい揺れの方向が予想でき、設計上の要求から図4(b)のように非拘束パターンに方向性があってもよい。
【0016】
▲7▼本発明の非拘束パターンは、ゴム層と硬質板の各接合面に均質に存在してもよいが、必要に応じて各接合面で変えてもよい。
すなわち、1枚の硬質板の両面のうち、一方は完全に接着された面、他方は非拘束パターンを導入してもよい。また、一連の異なった非拘束パターンを積層ゴム支承の上下に規則的に繰り返してもよい。この場合でも、非拘束状態が積層ゴム支承の各層により大きく異ならないようにするのがよい。
【0017】
次に、上述した本発明の非拘束パターンの製造方法、および、本発明の部分非拘束型積層ゴム支承について説明する。
本発明の非拘束パターンの効果は、その製造方法によらず、従って製造方法としては特に限定はなく、既存の技術により製造することができる。例えば、非拘束パターンの製造方法の例として、ゴム層と硬質板の接合面において接着する部分にのみゴム層もしくは硬質板に加硫接着用接着剤、常温硬化型接着剤等の接着剤を塗布しゴム層と硬質板を接着する方法、ゴム層と硬質板の接合面において非接着とする部分に離形剤を塗布、あるいはテフロンフィルム等の樹脂マスクを貼り、その他の部分にゴムセメント等の接着剤を塗布しゴム層と硬質板を接着する方法等を挙げることができる。
【0018】
本発明の部分非拘束型積層ゴム支承は、非拘束パターンを有する接合面を持つ安定板としての硬質板とゴム層とが、加硫接着用接着剤、常温硬化型接着剤等を介して接着され、このゴム層と硬質板とが繰り返し単位として積層されたことを特徴とする免震用支承である。ゴム層と硬質板との接合面は、少なくとも1層、好ましくは全層に非拘束パターンを有する。本発明の支承は、その形状や構造は施工される構造物の大きさや形状、施工場所に応じて種々のものが考えられ、特に限定されないが、橋梁用の場合は角柱状、建物用の場合には円柱状とするのが一般的である。また、ゴム層と硬質板の厚さ、大きさおよび形状は、支承が適用される用途に応じて適宜決定されるものであり、特に限定されない。
【0019】
硬質板は、支承内に安定板として用いるもので、従来公知の各種鋼板等が使用でき、特に限定されるものではないが、例えば、一般構造用鋼板、冷間圧延鋼板等が挙げられる。
【0020】
ゴム層としては公知の組成物を用いることができ、加硫ゴム、エステル系、アミド系、ウレタン系、スチレン系、オレフィン系、塩化ビニル系のエラストマー、さらにはこれらにゴムを分散させたエラストマー等の熱可塑性エラストマー、熱硬化性エラストマー等を用いることができる。
加硫ゴムに原料として用いる未加硫ゴムとしては、天然ゴム(NR)系、イソプレンゴム(IR)系、スチレン・ブタジエン共重合ゴム(SBR)系、天然ゴム/スチレン・ブタジエン共重合ゴム(NR/SBR)系、天然ゴム/ブタジエンゴム(NR/BR)系、天然ゴム/アクリロニトリルブタジエンゴム(NR/NBR)系等が好適に例示される。この未加硫ゴムには、必要に応じて、充填剤、可塑剤、老化防止剤、加硫剤、加硫促進剤、加硫助剤等の種々の添加剤を配合することができる。充填剤としては、HAFカーボン、SAFカーボン等のカーボンブラック等が、可塑剤としては、アロマオイル、ワックス等が、加硫剤としては、硫黄、亜鉛華等が、加硫促進剤としては、N−シクロヘキシル−2−ベンゾチアゾールスルフェンアミド(CBS)、ジベンゾチアジルジスルフィド(MBTS)等が、加硫助剤としては、ステアリン酸等が挙げられる。
【0021】
ゴム層と硬質板の非接着面以外の接着面は、加硫接着用接着剤、常温硬化型接着剤等の接着剤を介して加硫、接着しても、また、介さずに加硫してもよい。
常温硬化型接着剤は、フェノール系接着剤、ウレタン系接着剤、変性シリコーン接着剤、ゴム系接着剤、シアノアクリレート系接着剤、エポキシ系接着剤が挙げられるが、用いるゴムおよび硬質板の種類、必要とされる接着力等に応じて適宜決定すればよく、支承とした場合に圧縮破壊してもゴム破壊となる接着力とするのが好ましい。特に硬質板側には硬質板とのぬれ性の良い接着剤を用い、ゴム側にはゴムとのぬれ性の良い接着剤を用いて、この2層の接着剤間を強固に接着すれば高い接着力が得られる。好ましい硬質板とゴムと常温硬化型接着剤との組合せの例は、鋼板とエステル系ゴムとウレタン/ゴム系接着剤、鋼板とアミド系ゴムとフェノール/ゴム系接着剤が好適に例示される。
【0022】
フェノール系接着剤としては、ビニルフェノリック型、エポキシフェノリック型、ニトリルフェノリック型等が挙げられる。
ウレタン系接着剤としては、ポリイソシアネートとポリエーテルあるいはポリエステルポリオールを主原料とするプレポリマーをベースに、炭酸カルシウム、カーボンブラック等のフィラーと三級アミン、錫触媒等の添加剤を配合したものが挙げられる。ポリオールとしてエポキシ変性、ゴム変性体、ゴムの末端や内部に水酸基を付加したもの、フェノール樹脂等も接着向上のために好適に用いられる。
【0023】
変性シリコーン系接着剤は、ポリオールの末端をアルコキシシリル化したポリマーであり、一般的には鐘淵化学工業のMSポリマーが好適に用いられる。前記同様、フィラー、触媒等の添加剤を配合したもの、また、ポリオールは変性したものを用いることが好ましい。
ゴム系接着剤は、塩素化天然ゴム、クロロプレン、ポリブタジエン等のゴムと、テトラメチルチウラムジスルフィド(TT)やテトラメチルチウラムモノスルフィド(TS)等の低温硬化剤、フェノール樹脂、レゾール樹脂、イソシアネート等が添加された溶液タイプのものを用いればよい。フィラーを加えたものを用いるのが好ましい。
【0024】
シアノアクリレート系接着剤は、東亜合成化学(株)等から市販されている2−シアノアクリレート並びにその誘導体をベースとしたものを用いればよい。
エポキシ系接着剤は、グリシジルエーテル型、グリシジルエステル型、グリシジルアミン型、脂環型等のエポキシ樹脂と、ポリアミドアミン、ポリチオール、酸無水物等の硬化剤、触媒、フィラー等から構成されるものを用いればよい。
【0025】
支承の製造方法の一例について説明する。
まず、硬質板は、予め機械的処理、化学的処理、機械的加工等による表面処理をしてもよく、さらに表面を脱脂し、接着剤を塗布する。この際、プライマーを塗布してもよい。接着剤が乾燥した後、所定の厚さに圧延し、所定の形状に打ち抜かれた未加硫ゴムシートを積層する。この時、前述した非拘束パターンをゴムシートと硬質板の接合面に導入する。すなわち、ゴムシートと硬質板の接合面において接着する部分にのみ硬質板に接着剤等を塗布しゴムシートと硬質板を接着する。あるいは、ゴムシートと硬質板の接合面において非接着とする部分にのみ離形剤を塗布、もしくは、テフロンテープ等の樹脂マスクを貼り、その他の部分に接着剤を塗布しゴムシートと硬質板を接着する。このようにして非拘束パターンをゴムシートと硬質板の接合面に導入し、ゴムシートと硬質板の積層を繰り返して一体的に加硫した後、支承を得る。
【0026】
上述のようにして得られた本発明の部分非拘束型積層ゴム支承には、ゴム層と硬質板の接合面における非拘束パターンに由来する以下のような効果がある。
▲1▼ 支承の剪断剛性が減少する。
支承は、剪断剛性が小さいことにより、水平方向に柔らかい物体として振る舞うことから、地面の揺れが直接建物に伝わるのを抑制し建物等を保護する。したがって、剪断剛性が低いほうが好ましい。支承を構成するゴム自体の剪断剛性を小さくするのは現在すでに行われているが、ゴム自体の剪断剛性の低下には限界がある。また、ゴムがあまり柔らかいと他の機械的特性にマイナスの効果も出てくる。本発明では、ゴム層と硬質板の接合面に非拘束パターンを導入することにより、ゴムの性質の違いからでなく、構造の違いから、剪断剛性を減少させることができる。
【0027】
▲2▼ハードニング現象が抑制される。
ハードニング現象とは、ゴム層にかかる水平変位がある限界を越えると、それに伴う水平荷重が急激に増大する現象である。すなわち、積層ゴム支承としての剪断剛性値が急激に増大し、その結果、建造物の免震効果が大きな影響を受ける。また、建物の設計の際、ハードニング現象を考慮して設計するため設計が煩雑になる。
図7に、ゴム層として高減衰ゴム(HDR、High Damping Rubber )を用いた積層ゴム支承を例にとり、ゴム層と硬質板の接合面を完全加硫接着した従来の支承(□)と、ゴム層と硬質板の接合面に図2(e)に示す非拘束パターンをゴム層の片面に導入した本発明の支承(■)の、剪断歪み(横軸)に対する剪断弾性係数(縦軸)の値をプロットしたグラフを示す。剪断弾性係数は硬さを示す指標で、値が大きいほど硬いことを示す。従来の支承(□)も本発明の支承(■)も、歪みが小さい場合は硬く、歪みが大きくなると次第に柔らかく振る舞うようになる。しかし、さらに歪みが大きくなると、従来の支承(□)では、歪みに対し剪断弾性が軟化せず、それ以上柔らかくならず逆に硬くなる。すなわちハードニング現象が起こる。此れに対し、本発明の支承(■)では、ゴム層と硬質板の接合面の非拘束な部分が水平方向にある程度滑ることができるので、歪みがさらに大きくなってもハードニング現象が緩衝され水平方向の柔らかさを保持できる。
【0028】
▲3▼減衰性能(ダンピング効果)が向上する。
ゴム層と硬質板の接合面を完全加硫接着した従来の支承では、1度揺れだすと支承上の建造物のゆれがなかなかとまらず、揺れを吸収する減衰性能、即ちダンピング効果があまり高くない。しかしながら本発明の支承では、ゴム層と硬質板の接合面に非拘束パターンを導入しておりこの非拘束の部分でゴムと硬質板が密着しつつ滑るため、固体摩擦によるエネルギー吸収が起こり、ダンピング効果が向上、改善される。
【0029】
▲4▼非拘束面が離隔しているので、変形による応力集中が起こらない。
ゴム層と硬質板の外周部分のみ接着した支承では、ゴム層と硬質板の周縁部に応力が集中し、破断の危険が大きい。非拘束面が離隔・分散していると、応力の掛かり方はゴム層と硬質板の接合面に均一に分散し、応力集中が起きずより安全な支承となる。
▲5▼従来、提案されている両面非接着型の支承と比較して、支承としての基本的な機械的特性(鉛直剛性等)が良好且つ安定に維持されている。
両面非接着型の支承では、製作工程が減少できるものの、多くの基本的な機械的特性、例えば、鉛直方向の引張り特性等が犠牲となっている。
▲6▼さらに、本発明の支承の非拘束パターンの形成は、支承製作の製造工程に一工程を挿入するのみであるので容易に達成でき、本発明の支承製造は従来方法以上の複雑な工程を必要としない。
【0030】
本発明の支承は、上述の効果を有するので、例えば大型道路橋の支承や、ビルの基礎支承等に好適に使用可能である。
【0031】
【実施例】
以下、実施例により本発明をさらに具体的に説明する。
積層ゴム支承の製造
(実施例1)
ゴム層には、天然ゴムを使用した。ゴム一層は13.0cm角、厚さ0.54cmとした。硬質板には、鋼板(13.0cm角)を使用した。このゴム層4層と硬質板3層を交互に積層し、硬質板とゴム層は加硫接着し、硬質板とゴム層の接合面に図2(e)に示す非拘束パターンを導入して、部分非拘束型積層ゴム支承の実験用模型を作成した。非拘束パターンを構成する各円の直径は25mmとした。この非接着面のしめる面積は、全接合面の26%であった。
(比較例1)
接合面を100%接着した以外は、実施例1と同様にして、積層ゴム支承の実験用模型を作成した。
【0032】
積層ゴム支承の特性の評価
実施例1、比較例1で作成した支承について、剪断弾性係数(Gs)(ハードニング現象)と等価粘性減衰定数(heq)(ダンピング効果)を測定、評価した。測定方法と測定の結果を以下に示す。
1.剪断弾性係数(Gs)の測定
2軸剪断試験機により、面圧60kgf/cm2 、0.5Hzの条件にて繰り返し剪断変形を与え、剪断力の応答より剪断弾性係数(Gs)を求めた。結果を図8に示す。図中、横軸は剪断歪みの大きさ(%)、縦軸は、剪断弾性係数(Gs)(kgf/cm2 )、■は実施例1で作成した本発明の支承、□は比較例1で作成したゴム層と硬質板を完全接着した支承の測定値を示す。
図8から分かるように、部分非拘束型の積層ゴム支承である実施例1の本発明の支承では、比較例1の支承に比較して、剪断歪みが200%を越える大きな歪みを与えたところ、剪断弾性係数の減少が大きく、ハードニング現象が有効に抑制された。
【0033】
2.等価粘性減衰定数(heq)の測定
2軸剪断試験機により、面圧60kgf/cm2 、0.5Hzの条件にて繰り返し剪断変形を与え、ヒステリシスロス、剪断弾性係数(Gs)、最大変位振幅により等価粘性減衰定数(heq)を求めた。結果を図9に示す。図中、横軸は剪断歪みの大きさ(%)、縦軸は、等価粘性減衰定数(heq)、■は実施例1で作成した本発明の支承、□は比較例1で作成したゴム層と硬質板を完全接着した支承の測定値を示す。
図9から分かるように、部分非拘束型の積層ゴム支承である実施例1の本発明の支承では、比較例1の支承に比較して、剪断歪みが200%を越える大きな歪みを与えたところ、等価粘性減衰定数(heq)の増加が大きく、ダンピング効果が高かった。
【0034】
【発明の効果】
本発明の部分非拘束型積層ゴム支承は、ゴム層と硬質板の接合面において特定の非拘束パターンを導入することにより、従来の両面完全接着型積層ゴム支承の持つ安定性を維持しながら、従来の支承では得られない低い剪断剛性を有し、ハードニング現象が抑制され、同時に、減衰性能(ダンピング効果)に優れる。また、本発明の部分非拘束型積層ゴム支承において、非拘束パターンの形成は極めて容易である。従って、橋梁、建物等の建造物の免震用積層ゴム支承として好適に用いることができる。
【図面の簡単な説明】
【図1】 ゴム層と硬質板の間に非拘束パターンを有する本発明の支承の断面の概念図である。
【図2】 (a)〜(e)は本発明の支承が有する非拘束パターンの具体例を示す平面図である。
【図3】 支承のゴム層と硬質板の接合面における非拘束パターンの面積比率に対する安定性と減衰性能を表す等価粘性減衰定数の変化を概念的に示すグラフである。
【図4】 (a)〜(c)は本発明の支承が有する非拘束パターンの具体例を示す平面図である。
【図5】 本発明の非拘束パターンにおける最大長さの一例を示す平面図である。
【図6】 ゴム層と硬質板の接合面における非拘束パターンにおいて、非接着面の一部がゴム層と硬質板の周縁部分に接している非拘束パターンの一例を示す平面図である。
【図7】 部分非接着型積層ゴム支承と完全接着型積層ゴム支承における剪断歪みに対する剪断弾性係数の変化を示すグラフである。
【図8】 本発明の支承(実施例1)と完全接着型積層ゴム支承(比較例1)における剪断歪みに対する剪断弾性係数の変化を示すグラフである。
【図9】 本発明の支承(実施例1)と完全接着型積層ゴム支承(比較例1)における剪断歪みに対する等価粘性減衰定数の変化を示すグラフである。
[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a partially unconstrained laminated rubber bearing used for seismic isolation of structures.
[0002]
[Prior art]
In recent years, vibration energy absorbing devices, that is, anti-vibration, anti-vibration, seismic isolation devices and the like are rapidly spreading. As one form of such an absorption device, there is a laminated rubber for seismic isolation in which steel plates and rubber layers are alternately laminated. The seismic isolation laminated rubber behaves as a very hard object in the vertical direction and deviates greatly in the horizontal direction as in the case of a single rubber lump and behaves as a soft object. When used, it suppresses the ground shaking from being transmitted directly to buildings, etc., and when used as a support for bridges, etc., alleviates the vibration caused by the earthquake motion of the bridges. Protect.
[0003]
Today, a standard type of laminated rubber bearing for seismic isolation is a double-sided fully adhesive type in which the joining surface of a steel plate and a rubber layer is completely bonded. This type of laminated rubber bearing is excellent in stability because both sides of the joining surface of the steel plate and rubber layer are completely bonded. However, if the horizontal displacement on the rubber layer exceeds a certain limit, the horizontal load associated therewith suddenly increases. The effect of so-called hardening phenomenon that increases rapidly is great. That is, the horizontal rigidity as a laminated rubber bearing increases rapidly, and as a result, the seismic isolation effect of the building cannot be obtained sufficiently. Moreover, the vibration damping performance, that is, the damping effect is generally not so high.
On the other side of the laminated rubber bearing for seismic isolation, where the steel plate and rubber layer are completely bonded, a type in which the steel plate and rubber layer are completely non-bonded, for example, thin rubber is vulcanized and bonded around the steel plate A laminated rubber bearing (see Japanese Patent Application Laid-Open No. 6-50025) in which a vulcanized rubber sheet and a vulcanized rubber sheet are laminated completely without bonding has been proposed. However, because the non-adhesive structure in which the respective layers are brought into close contact with each other only with a load of a building or the like, when a vibration is applied, the non-adhesive joining surface is displaced and the rubber protrudes from the end of the face plate. In addition, when the entire building on the laminated rubber bearing is rocked by vibration, one side of the building is in a floating state, and the joint surface is removed. As an improved method of a laminated rubber bearing of the type in which the steel plate and the rubber layer are completely non-adhered, a laminated rubber bearing in which only the outer periphery of the steel plate and the rubber layer is bonded and restrained has been proposed. Although these laminated rubber bearings can simplify the manufacturing process, mechanical properties such as vertical rigidity and other shearing characteristics tend to be unstable, and are inferior in performance. Damping performance, that is, an increase in the damping effect, sometimes appears, but its appearance is not stable due to load conditions and repetition, so it cannot be used in the design of seismic isolation systems.
[0004]
In addition, the hollow restraint of a cylindrical restraint body in which a steel plate and a rubber layer are laminated is filled with a laminate of a hard plate and a viscoelastic plastic body as another structure, and the perimeter restraint of a structure in which the outer periphery is covered with vulcanized rubber A mold laminated rubber has been proposed (see JP-A-6-137378). This is a type of bearing in which a part of the steel plate and the rubber layer are non-adhered, but the outer peripheral part and the central part of the support are different, and the structure is complicated and the manufacturing process is complicated.
[0005]
[Problems to be solved by the invention]
The present invention has been made in view of the above circumstances, and its purpose is to maintain the stability of a double-sided fully-adhesive laminated rubber bearing while at the same time having low shear rigidity, suppressing the hardening phenomenon, and reducing the damping performance. It is to provide an improved partially unconstrained laminated rubber bearing.
[0006]
[Means for Solving the Problems]
  That is, the present invention provides a seismic isolation laminated rubber bearing in which rubber layers and hard plates are alternately laminated, with respect to the joining area on the joining surface of the rubber layer and the hard plate.20-50%In areaMultiple, evenly, without biasProvided is a partially unconstrained laminated rubber bearing having non-adhesive surfaces spaced apart from each other.
[0007]
The maximum length of the non-adhesive surface is preferably 1 to 10 times the thickness of the rubber layer.
[0008]
Furthermore, it is preferable that the entire non-adhesive surface is not in contact with the outer periphery of the bonding surface.
[0009]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the present invention will be described in more detail.
The partially unconstrained laminated rubber bearing (hereinafter referred to as a bearing) according to the present invention is characterized in that a specific partially unconstrained pattern is introduced into the joint surface between the rubber layer and the hard plate.
Here, the partial unconstrained pattern is a non-constrained pattern having a plurality of non-constrained portions each composed of a non-adhesive surface consisting of a plurality of spaced apart portions having different center positions, that is, a non-constrained surface and a continuous adhesive surface. Say.
[0010]
The unconstrained pattern of the present invention has the following features.
(1) The unconstrained pattern of the present invention is formed as a pattern of a non-adhesive portion on a conventional adhesive surface, that is, a joint surface between a rubber layer and a hard plate.
In FIG. 1, the conceptual diagram of the cross section of the support of this invention which has a non-restraining pattern in the joint surface of a rubber layer and a hard board is shown. In the figure, a thick line between the rubber layer and the hard plate indicates a constraining surface, and a thin line indicates a non-constraining surface. On the restraint surface, the joint surface between the rubber layer and the hard plate is firmly bonded by, for example, vulcanization bonding. On the other hand, on the non-constrained surface, even if the rubber layer and the hard plate are in close contact with each other, they are not bonded, and relative sliding is possible while exerting frictional force on each other.
FIG. 2 shows a specific example of the unconstrained pattern of the present invention.
[0011]
  2)The total area of the unconstrained pattern of the present invention is 70% or less of the bonding area between the rubber layer and the hard plate.
  Originally, laminated rubber bearings can vibrate in the horizontal direction due to rubber elasticity, and the natural vibration period in the horizontal direction can be longer than the vibration period of the maximum amplitude component of transverse waves such as earthquakes that cause destruction. It has a seismic isolation function that reduces and transmits the vibration speed and acceleration. In addition, a damping function that reduces the vibrations of buildings and the like that sway in a long cycle is also an important performance. Comparing the bearing in which the joining surface of the rubber layer and the hard plate is completely bonded to the bearing in which the partial unrestrained pattern is introduced into the joining surface of the rubber layer and the hard plate in terms of damping performance, As shown in the measurement of the equivalent viscous damping constant of a bearing having a constrained pattern, it is found that a bearing having a partially unconstrained pattern is improved with a large shaking (for example, a shearing strain reaching 200% or more). It was.
  FIG. 3 conceptually shows a graph of the change in stability and damping performance (change in equivalent viscous damping constant) with respect to the area ratio of the unconstrained pattern. The horizontal axis of the graph represents the area occupied by the unconstrained pattern on the joint surface, that is, the area ratio of the unconstrained pattern. The vertical axis on the left shows the stability of the laminated rubber bearing, specifically the value of the tensile rigidity in the vertical direction, and the vertical tensile rigidity in the laminated rubber bearing where the joint surface of the rubber layer and the hard plate is completely bonded. Is shown as a relative value with 100% as the value. The right vertical axis represents an equivalent viscous damping constant representing the damping performance of the laminated rubber bearing. The laminated rubber bearings all had the same structure except that the area of the unconstrained pattern was changed.
  As can be seen from FIG. 3, the improvement in damping performance (increase in equivalent viscous damping constant) by introduction of the unconstrained pattern is proportional to the area ratio of the unconstrained pattern to some extent. However, it can be seen that instability suddenly increases (stability decreases sharply) at a certain threshold..The effect of the attenuation performance appears when the area ratio of the unconstrained pattern is about 20%. Therefore, the area ratio of the unconstrained pattern is20-50%, preferably30 to 50%.
  The sum of the individual non-bonded parts is different for structures where laminated rubber bearings are used, for example buildings and bridges. That is, in a building, in order to buffer vibrations such as earthquakes, it is preferable that the rigidity in the horizontal direction is low, and the non-bonded portion of the joint surface between the rubber layer and the hard plate is preferably large. The bridge needs to have low rigidity in the vertical direction in order to buffer vibrations from vehicles traveling on the bridge. However, in the horizontal direction, it is necessary to increase the rigidity to some extent so that there is no risk of the bridge coming off. For this reason, the non-adhesive portion of the joint surface between the rubber layer and the hard plate is smaller in the bridge than in the laminated rubber bearing used in the building.
[0012]
(3) The unconstrained pattern of the present invention is composed of a plurality of spaced non-adhesive surfaces each having a different center of gravity.
The unconstrained pattern of the present invention is arranged on the joint surface of the rubber layer and the hard plate, preferably evenly spaced apart from each other. When vibration is received by such an arrangement, the slip generated on the joint surface is not uniformly concentrated on a specific portion of the joint surface, but is uniformly distributed over the entire joint surface, resulting in high stability. Therefore, the unconstrained pattern of the present invention does not include an unconstrained pattern having only one non-adhesive surface.
If the unconstrained pattern is continuous without being separated, for example, when water enters the bonding surface of the rubber layer and the hard plate, the rust spreads continuously if the hard plate is an iron plate or the like. There is a problem. However, if a plurality of unconstrained patterns are separated from each other, even if water enters, the area where the hard plate is rusted by the joint surface can be reduced.
As such an unconstrained pattern of the present invention, the unconstrained pattern shown in FIG. 2 and the unconstrained pattern shown in FIG. 4 can be exemplified.
[0013]
(4) The maximum length of each non-adhered portion constituting the non-restraining pattern of the present invention is preferably 1 to 10 times the thickness per rubber layer.
Here, the maximum length means, for example, the length of the diagonal line d as shown in FIG. 5 if it is a rectangle, the diameter if the unconstrained portion is a circle, and the long axis if it is an ellipse.
If the non-adhesive part is wide open in the center of the joint surface between the rubber layer and the hard plate, the restrained state of the peripheral part and the center part of the joint surface will be greatly different, and if this difference is too different, vibration energy will be applied. The joint surface is destroyed. Therefore, it is necessary to suppress the size of each separated non-bonded portion to be smaller than a certain size so that the constrained state generated on one joining surface does not vary greatly depending on the portion.
The maximum length of each non-adhered portion constituting the unconstrained pattern of the present invention is 1 to 10 times, preferably 3 to 8 times the thickness per rubber layer. If it is less than 1, effects such as attenuation performance do not appear. If it is more than 10 times, there is too much difference in the restrained state between the non-adhered part and the adhesive part, and it becomes unstable.
[0014]
(5) It is preferable that most or all of the separated non-adhesive surfaces constituting the unconstrained pattern of the present invention are arranged so as not to contact the peripheral portion of the rubber layer and the hard plate.
A specific example is shown in FIG. For example, in FIG. 6, there are 11 non-adhesive surfaces in contact with the peripheral portion out of 16 in total, which is not preferable. If there are many non-adhesive surfaces in contact with the peripheral portion, the rubber in the non-adhesive portion swells when repeated deformation is applied.
[0015]
(6) Although it is preferable that the unconstrained pattern of the present invention has no directionality, it may be present.
For example, in the case of laminated rubber bearings for buildings, it is considered that the direction in which the earthquake oscillates is omnidirectional, so it is necessary to have seismic isolation effects in all directions, as shown in Fig. 4 (a). It is preferable that the unconstrained pattern has no directionality. On the other hand, in the case of a long object such as a bridge, the direction of vibration to be suppressed can be predicted, and the unconstrained pattern may have directionality as shown in FIG.
[0016]
(7) The unconstrained pattern of the present invention may be present uniformly on each joint surface of the rubber layer and the hard plate, but may be changed on each joint surface as necessary.
That is, of both surfaces of one hard plate, one surface may be completely bonded, and the other surface may be introduced with an unconstrained pattern. Also, a series of different unconstrained patterns may be regularly repeated above and below the laminated rubber bearing. Even in this case, it is preferable that the unconstrained state is not greatly different for each layer of the laminated rubber bearing.
[0017]
Next, the manufacturing method of the above-mentioned unconstrained pattern of the present invention and the partially unconstrained laminated rubber bearing of the present invention will be described.
The effect of the unconstrained pattern of the present invention does not depend on the manufacturing method, and therefore the manufacturing method is not particularly limited, and can be manufactured by existing techniques. For example, as an example of a method for producing an unconstrained pattern, an adhesive such as a vulcanizing adhesive or a room temperature curable adhesive is applied to a rubber layer or a hard plate only on a portion where the rubber layer and the hard plate are bonded to each other. A method of adhering the rubber layer and the hard plate, applying a release agent to the non-adhering part on the joint surface of the rubber layer and the hard plate, or attaching a resin mask such as a Teflon film, and other parts such as rubber cement The method etc. which apply | coat an adhesive agent and adhere | attach a rubber layer and a hard board can be mentioned.
[0018]
In the partially unconstrained laminated rubber bearing of the present invention, a hard plate as a stabilizing plate having a joining surface having an unconstrained pattern and a rubber layer are bonded via an adhesive for vulcanization adhesion, a room temperature curing adhesive, or the like. And a base for seismic isolation characterized in that this rubber layer and a hard plate are laminated as a repeating unit. The joint surface between the rubber layer and the hard plate has an unconstrained pattern in at least one layer, preferably all layers. The support of the present invention may have various shapes and structures depending on the size, shape and construction location of the structure to be constructed, and is not particularly limited, but for a bridge, a prismatic shape, for a building In general, a cylindrical shape is used. Further, the thickness, size, and shape of the rubber layer and the hard plate are appropriately determined according to the application to which the support is applied, and are not particularly limited.
[0019]
The hard plate is used as a stabilizing plate in the support, and various conventionally known steel plates can be used. Although not particularly limited, for example, a general structural steel plate, a cold rolled steel plate, and the like can be given.
[0020]
Known compositions can be used as the rubber layer, such as vulcanized rubber, ester-based, amide-based, urethane-based, styrene-based, olefin-based, vinyl chloride-based elastomers, and elastomers in which rubber is dispersed. These thermoplastic elastomers and thermosetting elastomers can be used.
Unvulcanized rubber used as raw material for vulcanized rubber includes natural rubber (NR), isoprene rubber (IR), styrene / butadiene copolymer rubber (SBR), natural rubber / styrene / butadiene copolymer rubber (NR). / SBR), natural rubber / butadiene rubber (NR / BR) system, natural rubber / acrylonitrile butadiene rubber (NR / NBR) system and the like are preferable examples. Various additives such as a filler, a plasticizer, an anti-aging agent, a vulcanizing agent, a vulcanization accelerator, and a vulcanization aid can be blended with the unvulcanized rubber as necessary. As filler, carbon black such as HAF carbon, SAF carbon, etc., as plasticizer, aroma oil, wax, etc., as vulcanizing agent, sulfur, zinc white etc., as vulcanization accelerator, N -Cyclohexyl-2-benzothiazole sulfenamide (CBS), dibenzothiazyl disulfide (MBTS) and the like, and vulcanization aids include stearic acid and the like.
[0021]
Adhesive surfaces other than the non-adhesive surface of the rubber layer and the hard plate can be vulcanized or bonded via an adhesive such as a vulcanizing adhesive or a room-temperature curable adhesive, or not. May be.
Room temperature curable adhesives include phenolic adhesives, urethane adhesives, modified silicone adhesives, rubber adhesives, cyanoacrylate adhesives, epoxy adhesives, the types of rubber and hard plates used, What is necessary is just to determine suitably according to the adhesive force etc. which are required, and when setting it as a bearing, it is preferable to set it as the adhesive force which becomes rubber destruction even if it compresses and fractures. In particular, if the adhesive between the two layers is firmly adhered by using an adhesive with good wettability with the hard plate on the hard plate side and an adhesive with good wettability with rubber on the rubber side, it is high. Adhesive strength is obtained. Preferable examples of the combination of a hard plate, rubber and a room temperature curable adhesive are preferably a steel plate, an ester rubber, a urethane / rubber adhesive, a steel plate, an amide rubber and a phenol / rubber adhesive.
[0022]
Examples of phenolic adhesives include vinyl phenolic type, epoxy phenolic type, and nitrile phenolic type.
Urethane adhesives are based on prepolymers based on polyisocyanates and polyethers or polyester polyols, and contain fillers such as calcium carbonate and carbon black and additives such as tertiary amines and tin catalysts. Can be mentioned. As the polyol, epoxy-modified, modified rubber, those having a hydroxyl group added to the end or inside of the rubber, a phenol resin, and the like are also preferably used for improving adhesion.
[0023]
The modified silicone-based adhesive is a polymer obtained by alkoxysilylating the end of a polyol. In general, an MS polymer manufactured by Kaneka Chemical Industry is suitably used. As described above, it is preferable to use a compound in which additives such as a filler and a catalyst are blended, and a modified polyol.
Rubber adhesives include chlorinated natural rubber, chloroprene, polybutadiene, and other low temperature curing agents such as tetramethylthiuram disulfide (TT) and tetramethylthiuram monosulfide (TS), phenolic resins, resole resins, and isocyanates. An added solution type may be used. It is preferable to use a filler added.
[0024]
As the cyanoacrylate-based adhesive, those based on 2-cyanoacrylate and its derivatives commercially available from Toa Synthetic Chemical Co., Ltd. may be used.
Epoxy adhesives consist of epoxy resins such as glycidyl ether type, glycidyl ester type, glycidyl amine type, and alicyclic type, curing agents such as polyamidoamine, polythiol, acid anhydride, catalyst, filler, etc. Use it.
[0025]
An example of a method for manufacturing a bearing will be described.
First, the hard plate may be subjected to surface treatment by mechanical treatment, chemical treatment, mechanical processing or the like in advance, and the surface is degreased and an adhesive is applied. At this time, a primer may be applied. After the adhesive has dried, it is rolled to a predetermined thickness and an unvulcanized rubber sheet punched into a predetermined shape is laminated. At this time, the aforementioned unconstrained pattern is introduced into the joint surface between the rubber sheet and the hard plate. That is, an adhesive or the like is applied to the hard plate only at a portion where the rubber sheet and the hard plate are bonded to bond the rubber sheet and the hard plate. Alternatively, apply a release agent only to the non-adhesive part of the joint surface between the rubber sheet and the hard plate, or apply a resin mask such as Teflon tape, and apply an adhesive to the other part to attach the rubber sheet and the hard plate. Glue. In this way, the unconstrained pattern is introduced into the joint surface between the rubber sheet and the hard plate, and the support is obtained after the rubber sheet and the hard plate are repeatedly laminated and integrally vulcanized.
[0026]
The partially unconstrained laminated rubber bearing of the present invention obtained as described above has the following effects derived from the unconstrained pattern on the joint surface between the rubber layer and the hard plate.
(1) The shear rigidity of the bearing is reduced.
Since the bearing behaves as a soft object in the horizontal direction due to its low shear rigidity, it suppresses the ground shaking from being transmitted directly to the building and protects the building and the like. Therefore, it is preferable that the shear rigidity is low. Although reducing the shear rigidity of the rubber itself that constitutes the bearing has already been performed, there is a limit to lowering the shear rigidity of the rubber itself. Also, if the rubber is too soft, it will have a negative effect on other mechanical properties. In the present invention, by introducing an unconstrained pattern on the joint surface between the rubber layer and the hard plate, the shear rigidity can be reduced not only from the difference in rubber properties but also from the difference in structure.
[0027]
(2) Hardening phenomenon is suppressed.
The hardening phenomenon is a phenomenon in which, when the horizontal displacement applied to the rubber layer exceeds a certain limit, the accompanying horizontal load increases rapidly. That is, the shear rigidity value as a laminated rubber bearing increases rapidly, and as a result, the seismic isolation effect of the building is greatly affected. In addition, when designing a building, the design is complicated because it takes into account the hardening phenomenon.
Fig. 7 shows an example of a laminated rubber bearing using high damping rubber (HDR) as the rubber layer. The conventional bearing (□) with the rubber layer and hard plate joined together is completely vulcanized and bonded. 2 (e) of the present invention in which the unconstrained pattern shown in FIG. 2 (e) is introduced on one side of the rubber layer on the joining surface of the layer and the hard plate, the shear elastic modulus (vertical axis) of the shear strain (horizontal axis) The graph which plotted the value is shown. The shear elastic modulus is an index indicating hardness, and the larger the value, the harder. Both the conventional bearing (□) and the bearing (■) of the present invention are hard when the distortion is small, and gradually become soft when the distortion is large. However, when the strain is further increased, in the conventional bearing (□), the shear elasticity is not softened against the strain, and is not softened any more and is hardened. That is, a hardening phenomenon occurs. On the other hand, in the support (■) of the present invention, the non-restrained portion of the joint surface between the rubber layer and the hard plate can slide to some extent in the horizontal direction, so that the hardening phenomenon is buffered even if the strain further increases. The horizontal softness can be maintained.
[0028]
(3) Damping performance (damping effect) is improved.
In conventional bearings where the joint surface of the rubber layer and the hard plate is completely vulcanized and bonded, once the structure begins to sway, the structure of the structure on the bearing does not sway easily, and the damping performance that absorbs the vibration, that is, the damping effect is not very high. . However, in the support of the present invention, a non-restraining pattern is introduced on the joint surface between the rubber layer and the hard plate, and the rubber and the hard plate slide in close contact with each other. The effect is improved and improved.
[0029]
(4) Since non-restraining surfaces are separated, stress concentration due to deformation does not occur.
In a bearing in which only the outer peripheral portion of the rubber layer and the hard plate is bonded, stress concentrates on the peripheral portion of the rubber layer and the hard plate, and the risk of breakage is great. When the unconstrained surfaces are separated and dispersed, the stress is uniformly distributed on the joint surface between the rubber layer and the hard plate, and stress concentration does not occur, and the bearing becomes safer.
(5) Compared with the conventionally proposed double-sided non-adhesive type bearings, the basic mechanical properties (vertical rigidity, etc.) as the bearings are kept good and stable.
In the double-sided non-adhesive type bearing, although the manufacturing process can be reduced, many basic mechanical characteristics such as vertical tensile characteristics are sacrificed.
(6) Furthermore, the formation of the unconstrained pattern of the bearing according to the present invention can be easily achieved since only one step is inserted into the manufacturing process of the bearing manufacturing, and the bearing manufacturing according to the present invention is more complicated than the conventional method. Do not need.
[0030]
Since the bearing of the present invention has the above-described effects, it can be suitably used for, for example, a bearing on a large road bridge, a foundation bearing of a building, and the like.
[0031]
【Example】
Hereinafter, the present invention will be described more specifically with reference to examples.
Manufacture of laminated rubber bearings
(Example 1)
Natural rubber was used for the rubber layer. The rubber layer was 13.0 cm square and had a thickness of 0.54 cm. A steel plate (13.0 cm square) was used as the hard plate. 4 layers of rubber layers and 3 layers of hard plates are laminated alternately, the hard plates and the rubber layers are vulcanized and bonded, and an unconstrained pattern shown in FIG. An experimental model for partially unconstrained laminated rubber bearings was created. The diameter of each circle constituting the unconstrained pattern was 25 mm. The area to be bonded to the non-bonded surface was 26% of the total bonded surface.
(Comparative Example 1)
A laminated rubber bearing experimental model was prepared in the same manner as in Example 1 except that the bonded surfaces were bonded 100%.
[0032]
Evaluation of characteristics of laminated rubber bearings
About the bearing created in Example 1 and Comparative Example 1, the shear elastic modulus (Gs) (hardening phenomenon) and the equivalent viscous damping constant (heq) (Damping effect) was measured and evaluated. The measurement method and measurement results are shown below.
1. Measurement of shear modulus (Gs)
Using a biaxial shear tester, the surface pressure is 60 kgf / cm.2Shear deformation was repeatedly applied under the condition of 0.5 Hz, and the shear elastic modulus (Gs) was determined from the response of the shear force. The results are shown in FIG. In the figure, the horizontal axis is the shear strain magnitude (%), and the vertical axis is the shear elastic modulus (Gs) (kgf / cm2), ▪ indicate the measured value of the bearing of the present invention prepared in Example 1, and □ indicates the value of the bearing completely bonded to the rubber layer prepared in Comparative Example 1.
As can be seen from FIG. 8, in the bearing of the present invention of Example 1 which is a partially unconstrained laminated rubber bearing, compared with the bearing of Comparative Example 1, a shear strain exceeding 200% was given. The shear modulus was greatly reduced, and the hardening phenomenon was effectively suppressed.
[0033]
2. Equivalent viscous damping constant (heq) Measurement
Using a biaxial shear tester, the surface pressure is 60 kgf / cm.2, Repeated shear deformation under the condition of 0.5 Hz, equivalent viscosity damping constant (heq) The results are shown in FIG. In the figure, the horizontal axis is the shear strain magnitude (%), and the vertical axis is the equivalent viscous damping constant (heq), ▪ indicate the measured value of the bearing of the present invention prepared in Example 1, and □ indicates the value of the bearing completely bonded to the rubber layer prepared in Comparative Example 1.
As can be seen from FIG. 9, in the bearing of the present invention of Example 1 which is a partially unconstrained laminated rubber bearing, compared with the bearing of Comparative Example 1, a shear strain exceeding 200% was given. , Equivalent viscosity damping constant (heq) And the damping effect was high.
[0034]
【The invention's effect】
The partially unconstrained laminated rubber bearing of the present invention introduces a specific unconstrained pattern at the joint surface between the rubber layer and the hard plate, while maintaining the stability of the conventional double-sided fully adhered laminated rubber bearing, It has a low shear stiffness that cannot be obtained by conventional bearings, suppresses the hardening phenomenon, and at the same time has excellent damping performance (damping effect). In the partially unconstrained laminated rubber bearing of the present invention, it is very easy to form an unconstrained pattern. Accordingly, it can be suitably used as a laminated rubber bearing for seismic isolation of structures such as bridges and buildings.
[Brief description of the drawings]
FIG. 1 is a conceptual view of a cross section of a bearing of the present invention having an unconstrained pattern between a rubber layer and a hard plate.
FIGS. 2A to 2E are plan views showing specific examples of unconstrained patterns possessed by the support of the present invention.
FIG. 3 is a graph conceptually showing a change in an equivalent viscous damping constant representing stability and damping performance with respect to an area ratio of an unconstrained pattern at a joint surface between a rubber layer of a bearing and a hard plate.
FIGS. 4A to 4C are plan views showing a specific example of an unconstrained pattern included in the support of the present invention.
FIG. 5 is a plan view showing an example of a maximum length in an unconstrained pattern according to the present invention.
FIG. 6 is a plan view showing an example of a non-constraint pattern in which a part of a non-adhesive surface is in contact with a peripheral portion of a rubber layer and a hard plate in a non-constraint pattern on a joint surface between a rubber layer and a hard plate.
FIG. 7 is a graph showing changes in shear elastic modulus with respect to shear strain in a partially non-adhesive laminated rubber bearing and a fully adhered laminated rubber bearing.
FIG. 8 is a graph showing the change in the shear elastic modulus with respect to the shear strain in the bearing of the present invention (Example 1) and the fully bonded laminated rubber bearing (Comparative Example 1).
FIG. 9 is a graph showing a change in equivalent viscous damping constant with respect to shear strain in a bearing of the present invention (Example 1) and a fully bonded laminated rubber bearing (Comparative Example 1).

Claims (3)

ゴム層と硬質板とが交互に積層してなる免震用の積層ゴム支承において、前記ゴム層と前記硬質板の接合面に、接合面積に対して20〜50%の面積で、偏ることなく均一に、複数の互いに離隔した非接着面を有することを特徴とする部分非拘束型積層ゴム支承。In the laminated rubber bearing for seismic isolation formed by alternately laminating the rubber layer and the hard plate, the joint surface of the rubber layer and the hard plate has an area of 20 to 50% with respect to the joint area and is not biased. A partially unconstrained laminated rubber bearing having a plurality of non-adhesive surfaces spaced apart from each other uniformly . 前記非接着面の最大長さが、前記ゴム層1層当たりの厚みの1〜10倍である請求項1に記載の部分非拘束型積層ゴム支承。  2. The partially unconstrained laminated rubber bearing according to claim 1, wherein a maximum length of the non-adhesive surface is 1 to 10 times a thickness per one rubber layer. 前記非接着面の全部が前記接合面の外周に接していないことを特徴とする請求項1または2に記載の部分非拘束型積層ゴム支承。  3. The partially unconstrained laminated rubber bearing according to claim 1, wherein the entire non-adhesive surface is not in contact with the outer periphery of the joint surface.
JP929497A 1997-01-22 1997-01-22 Partially unconstrained laminated rubber bearing Expired - Fee Related JP3754517B2 (en)

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JP3754517B2 true JP3754517B2 (en) 2006-03-15

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