JP3733306B2

JP3733306B2 - Cylindrical vibration isolator

Info

Publication number: JP3733306B2
Application number: JP2001279012A
Authority: JP
Inventors: 隆志吉田; 勉田村; 益弘小川
Original assignee: Honda Motor Co Ltd; Sumitomo Riko Co Ltd
Current assignee: Honda Motor Co Ltd; Sumitomo Riko Co Ltd
Priority date: 2001-09-14
Filing date: 2001-09-14
Publication date: 2006-01-11
Anticipated expiration: 2021-09-14
Also published as: JP2003090375A

Description

【０００１】
【技術分野】
本発明は、主として軸直角方向の入力振動に対して防振効果を発揮し得る筒型防振装置に係り、特に、自動車用のエンジンマウントやボデーマウント，デフマウント，サスペンションブッシュ等として好適に用いられる筒型防振装置に関するものである。
【０００２】
【背景技術】
従来から、上述の如きエンジンマウント等として用いられる筒型防振装置の一種として、互いに径方向に離隔配置されたインナ軸部材とアウタ筒部材を本体ゴム弾性体で弾性的に連結すると共に、インナ軸部材を主たる振動入力方向となる軸直角方向一方向で挟んだ両側に、インナ軸部材とアウタ筒部材の間をそれぞれ軸方向に貫通して延びる一対の肉抜孔を設けることにより、ばね特性を調節すると共に本体ゴム弾性体への過大な引張応力の発生を回避するようにした構造のものが知られている。
【０００３】
ところで、このような筒型防振装置では、過大な荷重入力時にインナ軸部材とアウタ筒部材の相対的変位量を緩衝的に制限するストッパ機構を実現するために、貫通孔内に位置してアウタ筒部材からインナ軸部材に向かって突出するストッパゴムが好適に採用されるが、かかるストッパ機構においては、入力荷重が小さい条件下で発揮される初期ばねを柔らかく設定しつつ、ばね特性を非線形的に立ち上げて大荷重入力時にインナ軸部材とアウタ筒部材の相対的変位量を確実に制限することが要求される。
【０００４】
そこで、本出願人は、先に特開平１１−３３６８１７号公報において、ストッパゴムの軸方向両側でアウタ筒部材からインナ軸部材に向かって、ストッパゴムよりも小さな高さで突出して、ストッパゴムの基端部分を軸方向両側から拘束する一対の拘束凸部をアウタ筒部材に固設した筒型防振装置を、提案した。このような拘束凸部を設けることにより、ストッパゴムの全体ゴムボリュームを確保して、初期ばね特性を低く設定することが出来ると共に、過大な荷重入力時におけるストッパゴムの弾性変形量が制限されて、非線形的なばね特性が有利に実現され得るのである。
【０００５】
ところが、本発明者が更なる検討および研究を加えたところ、上述の如き一対の拘束凸部を設けたストッパゴムにおいては、過大な荷重の入力によってストッパゴムの突出方向先端面の中央部分に対して破裂状に亀裂が発生し易く、大きな耐荷重性能を実現することが難しいという、新たな課題を内在することが、明らかとなった。
【０００６】
【解決課題】
ここにおいて、本発明は、上述の如き事情を背景として為されたものであって、その解決課題とするところは、ストッパゴムの軸方向両側に一対の拘束凸部が形成されたストッパ機構において、柔らかい初期ばね特性と荷重増大に伴う非線形的なばね特性を十分に確保しつつ、大荷重入力時におけるストッパゴムの損傷が防止され得て、優れた耐荷重性能を発揮し得る、新規な構造の筒型防振装置を提供することにある。
【０００７】
【解決手段】
以下、このような課題を解決するために為された本発明の態様を記載する。なお、以下に記載の各態様において採用される構成要素は、可能な限り任意の組み合わせで採用可能である。また、本発明の態様乃至は技術的特徴は、以下に記載のものに限定されることなく、明細書全体および図面に記載され、或いはそれらの記載から当業者が把握することの出来る発明思想に基づいて認識されるものであることが理解されるべきである。
【０００８】
先ず、上述の如き従来構造の筒型防振装置におけるストッパゴムの損傷原因を究明すべく、本発明者が実験や解析を行って鋭意検討した結果、大荷重の入力に際してストッパゴムの突出先端部がインナ部材側に当接せしめられると、ポアソン比が略０．５であるストッパゴムは、高さ方向に圧縮変形せしめられた容積分だけ軸方向および周方向に拡がるが、その際ストッパゴムの軸方向両側が一対の拘束凸部によって構成されていることから、ストッパゴムには、周方向両側に逃げるように拡がる大きな変形が惹起されるのであり、その結果、ストッパゴムの中央部分には、周方向両側に引っ張る引張応力が集中的に作用し、以て、ストッパゴムの周方向中央部分に対して破裂的な損傷が生ぜしめられ易いのであろうことが明らかとなった。
【０００９】
そして、本発明は、このようにして得られた新たな知見に基づいて為されたものであって、本発明の第一の態様の特徴とするところは、円筒状外周面を有するインナ軸部材と、該インナ軸部材の外周側に離隔配置されたアウタ筒部材とに対して、それらインナ軸部材とアウタ筒部材の軸直角方向対向面間に介在せしめられた本体ゴム弾性体を直接に加硫接着せしめて、該インナ軸部材と該アウタ筒部材を該本体ゴム弾性体で弾性的に連結すると共に、該インナ軸部材を挟んだ軸直角方向両側に、該インナ軸部材と該アウタ筒部材の間をそれぞれ軸方向に貫通して延びる一対の肉抜孔を設け、更に該一対の肉抜孔の少なくとも一方に位置して、該アウタ筒部材から該インナ軸部材に向かって突出するストッパゴムを突出形成すると共に、該ストッパゴムの軸方向両側において該アウタ筒部材から該インナ軸部材に向かって該ストッパゴムよりも小さな高さで突出して、該ストッパゴムの基端部分を軸方向両側から拘束する一対の拘束凸部を設けた筒型防振装置において、前記ストッパゴムの突出先端面を中央部分よりも周方向両側で突出させて一対の先端突部を該ストッパゴムに一体形成し、これら一対の先端突部の各頂点を、該ストッパゴムの突出方向での投影において前記インナ軸部材の円筒状外周面に重なるように、該インナ軸部材の軸直角方向幅寸法よりも該各頂点間の周方向離隔距離を小さくしたことにある。
【００１０】
このような本態様に係る筒型防振装置においては、ストッパゴムの突出方向に振動荷重が入力されてストッパゴムの突出先端面インナ軸部材側に当接せしめられる際に、ストッパゴムの突出先端面に突設された一対の先端突部がインナ軸部材側に当接することにより、ストッパゴムの周方向両側部分に対して圧縮力が及ぼされるのであり、かかる周方向両側部分の圧縮力がストッパゴムの周方向中央部分に対して引張応力を軽減し或いは解消せしめるように作用せしめられることから、ストッパゴムに惹起される引張力が分散されて引張応力の最大値が低減され得て、ストッパ機構における耐荷重性能が有利に向上され得るのである。
【００１１】
しかも、本態様に係る筒型防振装置においては、ストッパゴムの全体ボリュームを確保して初期ばね特性を柔らかく設定しつつ、一対の拘束凸部でストッパゴムの軸方向両側への膨出変形を制限することにより、入力荷重の増大に伴う非線形的なばね特性が有利に発現され得るのである。
【００１２】
また、本態様に係る筒型防振装置においては、ストッパゴムの表面積が大きくなるので、入力荷重の増大に伴う表面応力を低くすることができ、亀裂の発生の防止ひいては耐久性の向上が図られる。
【００１３】
なお、本態様において、ストッパゴムの突出先端面の中央部分と一対の先端凸部との突出高さの差は、要求されるストッパ特性等に応じて適宜に決定されるものであって限定されるものでない。また、一対の先端凸部の具体的形状は特に限定されるものでないが、例えば、円弧形の山形断面形状で軸方向に延びる全体として蒲鉾形状等として有利に形成され得る。更にまた、一対の先端凸部を含むストッパゴムの突出先端部分は、全体として先細形状とされることが望ましく、それによって、初期ばね特性の更なる低減や耐久性の更なる向上が図られ得る。
【００１４】
また、本発明の第二の態様は、前記第一の態様に係る筒型防振装置において、前記一対の拘束凸部において前記インナ軸部材に対向位置せしめられた突出先端面上に、それぞれ、緩衝ゴム層を形成すると共に、該緩衝ゴム層の該インナ軸部材側への突出高さを、前記ストッパゴムの突出先端面の中央部分よりも小さくしたことを、特徴とする。このような本態様においては、入力荷重の増大に伴って、インナ軸部材に側に対してストッパゴムが当接せしめられて所定量だけ弾性変形せしめられた後に、緩衝ゴムがインナ軸部材に当接せしめられることとなる。その結果、入力荷重が大きくなった場合に、ストッパ機構におけるインナ軸部材が当接する受圧面積が、ストッパゴムの受圧面積に緩衝ゴムの受圧面積が加えられるのであり、受圧面積の急激な増大に基づいて、段階的な非線形ばね特性が実現されることにより、柔らかい初期ばね特性を確保しつつ、インナ軸部材とアウタ筒部材の相対的変位量をより確実に且つ緩衝的に制限することが可能となるのである。
【００１５】
更にまた、本発明の第三の態様は、前記第一又は第二の態様に係る筒型防振装置において、前記一対の拘束凸部間に位置せしめられて、前記ストッパゴムを支持する前記アウタ筒部材の内周面を、所定幅で周方向に直線的に延びる平坦面形状としたことを、特徴とする。このような本態様においては、アウタ筒部材におけるストッパゴムの支持面を有利に形成することが出来ると共に、ストッパゴムとして機能し得るボリュームを周方向で有利に確保することも可能となる。
【００１６】
また、本発明の第四の態様は、前記第一乃至第三の何れかの態様に係る筒型防振装置において、前記インナ軸部材の外周面を円筒形状とすると共に、該インナ軸部材の外周面を、前記本体ゴム弾性体によって全周に亘って被覆せしめたことを、特徴とする。このような本態様においては、インナ軸部材を被覆する本体ゴム弾性体に対してストッパゴムが当接せしめられることから、本体ゴム弾性体のばね特性もストッパ特性に利用することが出来るのであり、その分、ストッパゴムのゴムボリュームが小さくても初期のばね特性を柔らかく設定することが可能となる。特に、インナ軸部材の外周面が円筒形状とされていることから、ストッパゴムにおける一対の先端凸部が当接せしめられる部分において、インナ軸部材を被覆する本体ゴム弾性体の肉厚寸法が一層有利に確保され得る。
【００１７】
更にまた、本発明の第五の態様は、前記第一乃至第四の何れかの態様に係る筒型防振装置において、前記ストッパゴムにおける先端部分の軸方向寸法を、前記アウタ筒部材に設けられた前記一対の拘束凸部の先端部分における軸方向対向幅寸法よりも小さくしたことを、特徴とする。このような本態様においては、ストッパゴムに形成された先端部分の全体が一対の拘束凸部間で突出位置せしめられることとなり、かかる先端部分の全体において、荷重入力方向の有効寸法が大きく設定されることから、先端部分のインナ軸部材側への当接時の初期ばね特性が一層柔らかく設定され得る。
【００１８】
また、本発明の第六の態様は、前記第一乃至第五の何れかの態様に係る筒型防振装置において、前記ストッパゴムを、前記本体ゴム弾性体から独立して形成したことを特徴とする。このような本態様においては、ストッパゴムの存在やその弾性変形に伴う本体ゴム弾性体への影響が回避され得て、筒型防振装置における本来の防振性能が安定して発揮され得る。なお、ストッパゴムは、本体ゴム弾性体との間での応力の伝達が回避される状態であれば良く、例えば、ストッパゴムを本体ゴム弾性体から完全に独立して形成する他、アウタ筒部材の内周面を被覆する薄肉の被覆ゴム層によって相互に連結された構造をもって本体ゴム弾性体とストッパゴムを一体加硫成形することも可能である。
【００１９】
更にまた、本発明の第七の態様は、前記第一乃至第六の何れかの態様に係る筒型防振装置であって、前記一対の肉抜孔の一方の側だけに前記ストッパゴムが突出形成されていると共に、前記インナ軸部材が前記アウタ筒部材に対して該ストッパゴムの突出方向となる軸直角方向で該ストッパゴムと反対側に偏心位置せしめられており、前記本体ゴム弾性体が軸直角方向でＶ字形の断面形状とされて、該インナ軸部材から該ストッパゴムを挟んだ周方向両側にそれぞれ延び出す一対の弾性連結脚部によって該本体ゴム弾性体が構成されていることを、特徴とする。このような本態様に従えば、インナ軸部材がアウタ筒部材に対して、ストッパゴムの配設方向と反対側に偏心位置せしめられていることから、ストッパゴムが配設された方の肉抜孔を大きな断面形状として、ストッパゴムのゴムボリュームを一層有利に確保することが可能となる。また、このような本態様に従えば、例えば自動車用のエンジンマウント等のように装着状態下で静的な初期荷重が及ぼされる筒型防振装置が、有利に実現可能となる。
【００２０】
また、本発明の第八の態様は、前記第一乃至第七の何れかの態様に係る筒型防振装置であって、前記アウタ筒部材を合成樹脂製として、前記本体ゴム弾性体および前記ストッパゴムの存在下で該本体ゴム弾性体の表面を成形面の一部として該アウタ筒部材を成形することによって、該アウタ筒部材の成形と同時に該本体ゴム弾性体および該ストッパゴムが該アウタ筒部材に組み付けられていることを、特徴とする。このような本態様においては、本体ゴム弾性体やストッパゴムをアウタ筒部材に対して容易に組み付けることが可能となるのであり、特に、アウタ筒部材における一対の拘束凸部の間に嵌め込まれた状態で、ストッパゴムが容易に組み付けられるのである。なお、本態様において、好ましくは、本体ゴム弾性体と一体成形されたストッパゴムが採用されると共に、アウタ筒部材の内周面を周方向の全周に亘って被覆する被覆ゴム層が、それら本体ゴム弾性体およびストッパゴムと一体形成されることとなる。
【００２１】
【発明の実施形態】
以下、本発明を更に具体的に明らかにするために、本発明の実施形態について、図面を参照しつつ、詳細に説明する。
【００２２】
先ず、図１〜３には、本発明の一実施形態としての筒型防振装置である自動車用エンジンマウント１０が、示されている。このエンジンマウント１０は、インナ軸部材としての内筒部材１２と、該内筒部材１２の外周側に離隔配置されたアウタ筒部材としての外筒部材１４が、本体ゴム弾性体１６によって弾性的に連結された構造とされており、図示しない自動車のボデーとパワーユニットの間に介装されることにより、主として図１中の上下方向となる軸直角方向で内外筒部材１２，１４間に及ぼされる振動に対して有効な防振効果を発揮し得るようになっている。なお、以下の説明中、上下方向とは、原則として図１中の上下方向を言うものとする。
【００２３】
より詳細には、内筒部材１２は、金属製の管体によって形成されており、ストレートな厚肉円筒形状を有している。また、内筒部材１２の外周領域には、径方向外方に離隔して外筒部材１４が配設されている。かかる外筒部材１４は、例えば繊維補強されたポリアミド樹脂等の合成樹脂材によって形成されており、略一定幅寸法で周方向の全周に亘って延びる厚肉の略円筒体形状を有する本体筒部１８を備えている。
【００２４】
なお、本実施形態では、かかる本体筒部１８の底部２０が扁平状とされており、この底部２０の内周面が、主たる振動入力方向に対して略直交して拡がるストッパ支持面２２とされている。また、本体筒部１８は、主たる振動入力方向となる図１中の上下方向に延びる一つの径方向線を対称軸として左右両側が略線対称形状とされている。
【００２５】
また、本体筒部１８には、底部２２の軸方向両側部分において、それぞれ、内筒部材１２に向かって内周面上に突出する一対の拘束凸部２４，２４が一体成形されており、これら一対の拘束凸部２４，２４の対向面間には、底部２２上で所定幅をもって周方向に直線的に延びる凹所２６が形成されている。なお、拘束凸部２４，２４は、底部２２の周方向中央部分だけに周方向所定長さで一体成形されており、凹所２６の周方向両端部は、底部２２上で軸方向両側に開放されている。また、各拘束凸部２４は、周方向の全長に亘って高さが略一定とされており、その突出先端面２３が、軸方向所定幅で周方向に延びる平坦面形状とされている。更にまた、両拘束凸部２４，２４の軸方向対向面は、内筒部材１２側に向かって次第に拡開し、拘束凸部２４，２４の突出先端側に行くに従って次第に対向面間距離が大きくなる傾斜面２５とされている。
【００２６】
更にまた、外筒部材１４には、本体筒部１８における底部２０の軸方向両端面から斜め下方に延び出して軸方向外方に拡がる一対の取付脚部２８，２８が一体成形されており、両取付脚部２８，２８には、それぞれ、ボルト挿通用の金属スリーブ３０が厚さ方向に貫通状態で組み付けられている。
【００２７】
そして、かくの如き外筒部材１４に対して、内筒部材１２が、本体筒部１８の中空内部に挿通配置されており、本体筒部１８の中心軸に対して所定量だけ上方に偏心位置せしめられている。
【００２８】
而して、これら内筒部材１２と外筒部材１４（本体筒部１８）の間には、本体ゴム弾性体１６が介在せしめられており、本体ゴム弾性体１６によって内筒部材１２と外筒部材１４が弾性的に連結されている。かかる本体ゴム弾性体１６は、全体として逆向きの略Ｖ字形の断面形状で軸方向に延びており、Ｖ字の中央屈曲部に対して内筒部材１２が貫通配置されており、本体ゴム弾性体１６が内筒部材１２の外周面に対して加硫接着されている一方、Ｖ字の両先端部は、外筒部材１４の本体筒部１８の内周面に固着されている。なお、内筒部材１２の軸方向中間部分は、本体ゴム弾性体１６に埋設状態とされており、内筒部材１２の外周面が、本体ゴム弾性体１６によって全周に亘って被覆されている。
【００２９】
換言すれば、本体ゴム弾性体１６は、内筒部材１２から外筒部材１４に向かってそれぞれ延び出す一対の弾性連結脚部３２，３２によって構成されているのであり、特に本実施形態では、これら一対の弾性連結脚部３２，３２が、外筒部材１４に対する内筒部材１２の偏心方向と反対側（図１中の下方向）に向かって拡開する所定の中心角度をもって斜め下方に延び出して形成されており、内筒部材１２の中心軸を通って上下方向に延びる一つの径方向線を対称軸として左右両側が略線対称形状とされている。なお、各弾性連結脚部３２，３２にあっては、内筒金具１２の中心軸回りの肉厚寸法が、内筒部材１２から外筒部材１４に行くに従って次第に小さくされている。
【００３０】
また一方、外筒部材１４の本体筒部１８の内周面には、周方向全周に亘って略一定の肉厚寸法で連続して延びて、該本体筒部１８の内周面を略全面に亘って覆う被覆ゴム層３４が形成されて固着されており、この被覆ゴム層３４に対して、本体ゴム弾性体１６を構成する弾性連結脚部３２，３２の外方先端部が一体的に連結されている。要するに、本体ゴム弾性体１６は、被覆ゴム層３４と一体成形されているのである。
【００３１】
これにより、内筒部材１２と外筒部材１４の間には、本体ゴム弾性体１６を挟んだ上下両側において、それぞれ軸方向に貫通して延びる上側肉抜孔３６と下側肉抜孔３８が設けられている。そして、上側肉抜孔３６には、内筒部材１２から外筒部材１４に向かって上方に突出するリバウンドストッパ４０が配設されている。このリバウンドストッパ４０は、本体ゴム弾性体１６と一体成形されており、内筒部材１２の軸方向中央部分において、略山形断面で軸方向に所定長さで延びて形成されている。
【００３２】
また一方、下側肉抜孔３８には、外筒部材１４から内筒部材１２に向かって上方に突出するストッパゴムとしてのバウンドストッパ４２が配設されている。なお、このバウンドストッパ４２は、外筒部材１４における本体筒部１８の内周面を被覆する被覆ゴム層３４と一体成形されている。要するに、本実施形態では、上述の本体ゴム弾性体１６が、被覆ゴム層３４やリバウンドストッパ４０，バウンドストッパ４２を含む一体加硫成形品として形成されているのである。なお、本体筒部１８の内周面を被覆する被覆ゴム層３４は、本体筒部１８に突設された一対の拘束凸部２４，２４の突出先端面２３，２３にまで延び出しており、それによって、拘束凸部２４，２４の突出先端面２３，２３上には、略一体の肉厚寸法で拡がる緩衝ゴム層４４が被着形成されている。
【００３３】
そして、バウンドストッパ４２は、本体筒部１８の底部２０に形成されたストッパ支持面２２の周方向中央部分において、ストッパ支持面２２よりも僅かに短い周方向長さを有している。また、バウンドストッパ４２の突出高さは、底部２０に突設された拘束凸部２４，２４の突出高さよりも大きく設定されている。これにより、バウンドストッパ４２の基端部分が、拘束凸部２４，２４間の凹所２６内に埋め込まれた状態で位置せしめられて、凹所２６の底面（ストッパ支持面２２）や拘束凸部２４，２４の傾斜面２５，２５に対して固着されている一方、バウンドストッパ４２の先端部分は、拘束凸部２４，２４間の凹所２６から下側肉抜孔３８内に突出して、内筒部材１２に向かって延び出している。なお、図２から明らかなように、バウンドストッパ４２は、一対の拘束凸部２４，２４の上端開口部における対向面間距離よりも小さな軸方向寸法をもって下側肉抜孔３８内に突設されている。
【００３４】
さらに、バウンドストッパ４２において、拘束凸部２４，２４間の凹所２６から突出せしめられた部分は、軸方向及び周方向において突出先端側に行くに従って先細形状となるように、外周面が軸方向および周方向で傾斜せしめられている。また、バウンドストッパ４２の突出先端面は、軸方向において、凹所２６の底面と同じか僅かに小さな寸法を有すると共に、周方向において、拘束凸部２４，２４よりも僅かに小さな寸法を有し、本体ゴム弾性体１６における内筒部材１２の埋設部位に対して上下方向に所定距離を隔てて対向位置せしめられている。
【００３５】
また、バウンドストッパ４２の突出先端面には、周方向の両端部分において、略円弧形で一定の断面形状をもって軸方向に延びる、全体として蒲鉾形状を有する一対の先端突部４６，４６が、一体的に形成されている。そして、バウンドストッパ４２の突出先端面の周方向中央部分は、これら一対の先端突部４６，４６の間に位置せしめられることにより、谷形状の中央谷部４８とされており、中央谷部４８の突出高さよりも、周方向両側に形成された先端突部４６，４６の突出高さの方が大きくされている。
【００３６】
なお、これら先端突部４６，４６の各突出頂点は、図１に示されているように、何れも、主たる振動入力方向となる上下方向の投影において、内筒部材１２に重なるように位置決めされている。また、中央谷部４８は、外筒部材１４の拘束凸部２４，２４上に形成された緩衝ゴム層４４の表面よりも、所定量だけ内筒部材１２側に突出した位置に設定されている。
【００３７】
ところで、上述の如き構造とされたエンジンマウント１０は、内筒部材１２に対して加硫接着された本体ゴム弾性体１６の一体加硫成形品と、外筒部材１４とを、それぞれ別体形成せしめた後に、外筒部材１４に本体ゴム弾性体１６を組み付けて接着等を施すことも可能であるが、好適には、例えば（ａ）本体ゴム弾性体１６の加硫成形型の成形キャビティに、別途製作した内筒部材１２と外筒部材１４を位置決めセットせしめた状態下で、かかる成形キャビティに所定のゴム材料を充填し、本体ゴム弾性体１６を加硫成形すると同時に、内外筒部材１２，１４に組み付けて加硫接着せしめる方法や、（ｂ）外筒部材１４の樹脂成形型の成形キャビティに、予め加硫成形して内筒部材１２に加硫接着せしめた本体ゴム弾性体１６の一体加硫成形品を位置決めセットせしめた状態下で、かかる成形キャビティに所定の樹脂材料を充填し、外筒部材１４の成形と同時に、本体ゴム弾性体１６を外筒部材１４に接着して組み付ける方法などが、採用される。特に、後者（ｂ）の製造方法に従えば、本体ゴム弾性体１６の加硫収縮等に起因する引張応力の発生を軽減乃至は解消せしめて耐久性の向上を図ることも可能となる。
【００３８】
そして、上述の如き構造とされたエンジンマウント１０は、図面上に明示はされていないが、外筒部材１４の取付脚部２８，２８が、金属スリーブ３０に挿通されるボルトにより自動車のボデーに固着される一方、内筒部材１２が、その中心孔に挿通されるロッドにより自動車のパワーユニットに固着されることによって、自動車のパワーユニットとボデーの間に装着されることとなり、それによって、パワーユニットをボデーに対して防振支持せしめるようにされる。なお、このような装着状態下では、内外筒部材１２，１４間に対して、パワーユニットの静的な分担支持荷重が上下方向に及ぼされることにより、本体ゴム弾性体１６が所定量だけ弾性変形せしめられて、内外筒部材１２，１４が略同軸上に位置せしめられることとなる。
【００３９】
また、かかる装着状態下では、バウンドストッパ４２およびリバウンドストッパ４０と、それらの突出先端面に対して上下方向で対向位置せしめられた内筒部材１２上の本体ゴム弾性体１６および外筒部材１４上の被覆ゴム層３４の間には、何れも、所定量の間隙が存在せしめられるようになっている。そして、車両の走行に際して大きな振動荷重が入力されて本体ゴム弾性体１６の弾性変形に伴って内外筒部材１２，１４が上下方向で相対変位せしめられた場合に、バウンドストッパ４２が内筒部材１２上の本体ゴム弾性体１６に当接せしめられることにより、或いはリバウンドストッパ４０が外筒部材１４上の被覆ゴム層３４に当接せしめられることにより、内外筒部材１２，１４におけるバウンド方向およびリバウンド方向の相対的変位量が緩衝的に制限されるようになっているのである。
【００４０】
ここにおいて、バウンドストッパ４２は、軸方向両側を一対の拘束凸部２４，２４で拘束されていることから、大荷重入力時における過大な弾性変形量や歪みを抑えつつ、外筒部材１４におけるストッパ支持面２２からの突出高さ寸法を大きく設定することが出来るのであり、それによって、バウンドストッパ４２の内筒部材１２側への当接初期におけるばね特性を十分に柔らかく設定することが出来ると共に、大きな振動荷重の入力時に発揮されるばね剛性を大きく設定して、内外筒部材１２，１４の相対的変位量を確実に安定して制限することが可能となるのであり、全体として非線形的な荷重−撓み特性、即ち非線形的なばね特性が、有利に実現され得て、ショック感や打音が無く、有効な変位量制限効果を発揮し得るストッパ機構が実現され得るのである。
【００４１】
しかも、かかるバウンドストッパ４２においては、内筒部材１２に対して主たる振動の入力中心軸上で対向位置する中央谷部４８よりも、周方向両側に離隔した位置で内筒部材に１２に対して対向位置せしめられた先端突部４６，４６の方が、内筒部材１２側に向かって大きく突出せしめられており、振動入力時において、中央谷部４８よりも先端突部４６，４６の方が、小さな入力荷重で先に内筒部材１２側の本体ゴム弾性体１６に対して当接せしめられることとなる。それ故、両先端突部４６，４６が圧縮変形せしめられることにより、バウンドストッパ４２には、周方向の両側部分において有効な圧縮力が生ぜしめられるのであり、この圧縮力がバウンドストッパ４２の周方向中央部分に対しても圧縮力として及ぼされることとなる。
【００４２】
従って、バウンドストッパ４２が大きく圧縮変形せしめられた場合にも、バウンドストッパ４２における発生応力が全体として分散され易くなって、バウンドストッパ４２の周方向中央部分に対して集中的に生ぜしめられる周方向両側への引張応力が軽減乃至は解消され得るのであり、その結果、バウンドストッパ４２の耐荷重強度や耐久性が有利に向上され得るのである。
【００４３】
しかも、バウンドストッパ４２における一対の先端突部４６，４６の各突出頂点が、荷重入力方向で内筒部材１２に対して重なり合うように形成されていることから、これら先端突部４６，４６を通じてバウンドストッパ４２に圧縮荷重が効率的に及ぼされ得るのであり、先端突部４６，４６の周方向離隔方向への倒れ込み的な変形も防止されて、両先端突部４６，４６の圧縮変形に基づく上述の如き中央谷部４８の引張応力の軽減効果がより効果的に発揮され得るのである。
【００４４】
加えて、バウンドストッパ４２は、一対の先端突部４６，４６と中央谷部４８により内筒部材１２側への当接面に凹凸が付されて波状面とされ、その表面積が大きくされていることから、内筒部材１２側への当接に伴って生ぜしめられるバウンドストッパ４２の表面応力が低減されることとなり、それによって、バウンドストッパ４２における亀裂の発生防止や耐久性の向上が、より有効に達成され得るのである。
【００４５】
また、本実施形態では、内筒部材１２の外周面が円筒形状とされていることから、内筒部材１２を被覆する本体ゴム弾性体１６によって形成されて、バウンドストッパ４２の先端突部４６，４６が当接せしめられる内筒部材１２側の被当接部位におけるゴム厚が有利に確保され得るのであり、それによって、バウンドストッパ４２の当接に際しての初期ばね特性を、バウンドストッパ４２の突出高さを大きくすることなく、より柔らかく設定することが可能となる。
【００４６】
さらに、本実施形態では、大きな振動荷重の入力に際して、内筒部材１２側が、初めにバウンドストッパ４２の先端凸部４６，４６に当接した後、中央谷部４８を潰すようにして、バウンドストッパ４２の突出先端面の略前端に亘って当接し、その後、緩衝ゴム層４４，４４を介して拘束凸部２４，２４に当接せしめられるようにされているのであり、それによって、初期に柔らかくて入力荷重が大きくなるに従って非線形的に硬くなり、最終的には内外筒部材１２，１４の相対的変位量を確実に規制し得る、目的とするストッパ機構が、一層有利に実現され得るのである。
【００４７】
以上、本発明の実施形態について詳述してきたが、これはあくまでも例示であって、本発明は、かかる実施形態における具体的な記載によって、何等、限定的に解釈されるものではない。
【００４８】
例えば、前記実施形態では、バウンド方向のストッパ機構だけが、本発明に従うストッパゴムによって構成されていたが、バウンド方向のストッパ機構に加えて、或いはバウンド方向のストッパ機構に代えて、リバウンド方向のストッパ機構を、本発明に従うストッパゴムによって構成することも、勿論、可能である。
【００４９】
また、前記実施形態では、拘束凸部２４，２４が、外筒部材１４における本体筒部１８の底部２０の中央部分だけに所定長さで形成されていたが、拘束凸部２４，２４の周方向長さや突出高さ等は、要求されるストッパ機構の特性等に応じて適宜に変更されるものであって、限定されるものではない。具体的には、例えば、図４〜５に示すように、拘束凸部２４，２４を本体筒部１８の底部の全長に亘って形成して、バウンドストッパ４２の基端部分を周方向の略全部に亘って拘束した構成等も採用可能であり、このような構成によれば、バウンドストッパ４２によるばね特性の立ち上がりを一層大きくしたり、耐久性の更なる向上を図ることが可能となる。なお、図４〜５においては、その理解を容易とするために、前記実施形態と同様な構造とされた部材および部位に対して、それぞれ、図中に、前記実施形態と同一の符号を付しておく。また、図４〜５に示されたエンジンマウントにおける縦断面図は、前記実施形態の縦断面図と略同一に表されることから、図示を省略する。
【００５０】
また、前記実施形態では、略Ｖ字形の断面形状で軸方向に延びる本体ゴム弾性体１６が採用されていたが、本体ゴム弾性体の具体的形状は、要求される防振特性や耐荷重性能等を考慮して適宜に決定されるものであって、限定されるものでない。具体的には、例えば、内外筒部材１２，１４を同一中心軸上に配置せしめて、それら内外筒部材１２，１４の対向面間で、内筒部材１２を挟んだ両側に直径方向一方向で直線的に延びる断面形状を有する本体ゴム弾性体を採用することも可能であり、このような本体ゴム弾性体は、例えばサスペンションブッシュやエンジンロールマウント等、装着状態下で及ぼされる静的な初期荷重が極めて小さいか略０である場合に有利に採用され得る。
【００５１】
さらに、前記実施形態では、金属製の内筒部材と合成樹脂製の外筒部材が採用されていたが、内外筒部材の材質に制限はなく、要求される強度や特性，使用条件等を考慮して適宜に選定され得る。
【００５２】
また、外筒部材１４における取付脚部２８，２８は、必ずしも必要ではなく、例えば円筒形の外周面を有する外筒部材を採用して、自動車のサスペンション機構等において、アームアイ等の装着用孔に外筒部材を圧入して組み付けることも可能である。
【００５３】
更にまた、前記実施形態では、一対の拘束凸部２４，２４が外筒部材１４の本体筒部１８に一体形成されていたが、これら拘束部材を外筒部材１４と別体形成して本体筒部１８に後固定して形成することも可能である。
【００５４】
加えて、前記実施形態では、本発明を自動車用のエンジンマウントに対して適用したものの具体例を示したが、本発明は、自動車用のボデーマウントやデフマウント，サスペンションブッシュ、或いは自動車以外の各種装置に用いられる筒型防振装置に対して、何れも、適用可能である。
【００５５】
その他、一々列挙はしないが、本発明は、当業者の知識に基づいて種々なる変更，修正，改良等を加えた態様において実施され得るものであり、また、そのような実施態様が、本発明の趣旨を逸脱しない限り、何れも、本発明の範囲内に含まれるものであることは、言うまでもない。
【００５６】
【発明の効果】
上述の説明から明らかなように、本発明に従う構造とされた筒型防振装置においては、大きな荷重が入力されてストッパゴムがインナ軸部材側に当接せしめられた際に、ストッパゴムの周方向両側に突設された一対の先端凸部がインナ軸部材に対して当接せしめられて、ストッパゴムの周方向両側に有効な圧縮力が及ぼされることとなり、この圧縮力が、ストッパゴムの周方向中間部分に生ぜしめられる引張力を軽減するように作用せしめられることによって、ストッパゴムの周方向中間部分における破裂的な損傷が効果的に軽減乃至は回避され得るのであり、それによって、ストッパゴム、延いては防振装置において、優れた耐荷重性能と耐久性が実現され得るのである。
【図面の簡単な説明】
【図１】本発明の一実施形態としてのエンジンマウントを示す横断面図である。
【図２】図１におけるII−II断面図である。
【図３】図２における左側面図である。
【図４】本発明の別の実施形態としてのエンジンマウントを示す、図３に対応した左側面図である。
【図５】図４に示されたエンジンマウントを示す、図１に対応した横断面図である。
【符号の説明】
１０エンジンマウント
１２内筒部材
１４外筒部材
１６本体ゴム弾性体
１８本体筒部
２２ストッパ支持面
２４拘束凸部
２６凹所
３２弾性連結脚部
３４被覆ゴム層
３６上側肉抜孔
３８下側肉抜孔
４０リバウンドストッパ
４２バウンドストッパ
４４緩衝ゴム層
４６先端突部
４８中央谷部[0001]
【Technical field】
The present invention relates to a cylindrical vibration isolator capable of exhibiting an anti-vibration effect mainly against an input vibration in a direction perpendicular to the axis, and particularly suitably used as an engine mount, body mount, differential mount, suspension bush, etc. for an automobile. The present invention relates to a cylindrical vibration isolator.
[0002]
[Background]
Conventionally, as a type of cylindrical vibration isolator used as an engine mount as described above, an inner shaft member and an outer cylinder member that are spaced apart from each other in the radial direction are elastically connected by a main rubber elastic body, and an inner By providing a pair of hollow holes extending in the axial direction between the inner shaft member and the outer cylinder member on both sides of the shaft member sandwiched in one direction perpendicular to the axis that is the main vibration input direction, the spring characteristics are improved. There is known a structure that adjusts and avoids generation of excessive tensile stress on the main rubber elastic body.
[0003]
By the way, in such a cylindrical vibration isolator, in order to realize a stopper mechanism for buffering the relative displacement amount of the inner shaft member and the outer cylinder member when an excessive load is input, it is located in the through hole. A stopper rubber that protrudes from the outer cylinder member toward the inner shaft member is preferably used. However, in such a stopper mechanism, the initial spring exerted under a condition where the input load is small is set softly, and the spring characteristics are nonlinear. Therefore, it is required to reliably limit the relative displacement between the inner shaft member and the outer cylinder member when a large load is input.
[0004]
In view of this, the present applicant previously disclosed in Japanese Patent Application Laid-Open No. 11-336817 that the stopper rubber protrudes from the outer cylindrical member toward the inner shaft member at both sides in the axial direction of the stopper rubber at a height smaller than the stopper rubber. A cylindrical vibration isolator has been proposed in which a pair of constraining projections that constrain the proximal end portion from both sides in the axial direction are fixed to the outer tubular member. By providing such constraining convex portions, the entire rubber volume of the stopper rubber can be secured, the initial spring characteristics can be set low, and the amount of elastic deformation of the stopper rubber when an excessive load is input is limited. A non-linear spring characteristic can be advantageously realized.
[0005]
However, as a result of further investigation and research by the present inventor, in the stopper rubber provided with a pair of restraining protrusions as described above, an excessive load is applied to the central portion of the front end surface of the stopper rubber in the protruding direction. As a result, it has become clear that there is a new problem that cracks tend to occur and it is difficult to achieve large load-bearing performance.
[0006]
[Solution]
Here, the present invention was made against the background as described above, and the solution to the problem is a stopper mechanism in which a pair of restraining protrusions are formed on both sides in the axial direction of the stopper rubber. A new structure with a soft initial spring characteristic and a non-linear spring characteristic that accompanies an increase in load, while preventing damage to the stopper rubber at the time of heavy load input and exhibiting excellent load bearing performance. The object is to provide a cylindrical vibration isolator.
[0007]
[Solution]
Hereinafter, the aspect of this invention made | formed in order to solve such a subject is described. In addition, the component employ | adopted in each aspect as described below is employable by arbitrary combinations as much as possible. In addition, aspects or technical features of the present invention are not limited to those described below, but are described in the entire specification and drawings, or can be understood by those skilled in the art from those descriptions. It should be understood that it is recognized on the basis of.
[0008]
First, in order to investigate the cause of damage to the stopper rubber in the cylindrical vibration isolator having the conventional structure as described above, the present inventor conducted an experiment and analysis, and as a result of extensive studies, as a result of the protruding tip of the stopper rubber when inputting a large load. Is brought into contact with the inner member side, the stopper rubber having a Poisson's ratio of approximately 0.5 expands in the axial direction and the circumferential direction by the volume compressed and deformed in the height direction. Since both sides in the axial direction are constituted by a pair of constraining convex portions, the stopper rubber is caused to undergo a large deformation spreading so as to escape to both sides in the circumferential direction.As a result, in the central portion of the stopper rubber, It has been clarified that the tensile stress pulling on both sides in the circumferential direction acts intensively, so that it is likely to cause bursting damage to the circumferential central portion of the stopper rubber.
[0009]
And this invention was made based on the new knowledge acquired in this way, Comprising: The place made into the characteristics of the 1st aspect of this invention is the following. Has a cylindrical outer peripheral surface An inner shaft member, and an outer cylinder member spaced apart on the outer peripheral side of the inner shaft member; Against The rubber elastic body of the main body interposed between the opposed surfaces of the inner shaft member and the outer cylinder member in the direction perpendicular to the axis The inner shaft member and the outer cylinder member are bonded to the main rubber elastic body by directly vulcanizing and bonding And a pair of hollow holes extending in the axial direction between the inner shaft member and the outer cylinder member are provided on both sides in the direction perpendicular to the axis across the inner shaft member. A stopper rubber that protrudes from the outer cylindrical member toward the inner shaft member is formed to protrude from the outer cylindrical member on both sides of the stopper rubber in the axial direction. In the cylindrical vibration isolator provided with a pair of restraining protrusions that project toward a member at a height smaller than the stopper rubber and restrain the base end portion of the stopper rubber from both sides in the axial direction, the stopper rubber projects A pair of tip protrusions are formed integrally with the stopper rubber by projecting the tip surfaces on both sides in the circumferential direction from the central portion, and the vertices of the pair of tip protrusions are projected in the protrusion direction of the stopper rubber. Oite the inner shaft member Cylindrical outer peripheral surface The circumferential distance between the vertices is made smaller than the width perpendicular to the axis of the inner shaft member.
[0010]
In such a cylindrical vibration isolator according to this aspect, when a vibration load is input in the stopper rubber protruding direction and brought into contact with the protruding tip surface of the stopper rubber on the inner shaft member side, the protruding tip of the stopper rubber When a pair of tip protrusions projecting from the surface abuts on the inner shaft member side, a compressive force is exerted on both sides in the circumferential direction of the stopper rubber, and the compressive forces on both sides in the circumferential direction are applied to the stopper. Since it acts to reduce or eliminate the tensile stress with respect to the central part in the circumferential direction of the rubber, the tensile force induced in the stopper rubber can be dispersed and the maximum value of the tensile stress can be reduced, and the stopper mechanism Thus, the load bearing performance can be advantageously improved.
[0011]
In addition, in the cylindrical vibration isolator according to this aspect, the stopper rubber is bulged and deformed in the axial direction on both sides of the stopper rubber while securing the entire volume of the stopper rubber and setting the initial spring characteristics softly. By limiting, a non-linear spring characteristic with an increase in input load can be advantageously developed.
[0012]
Further, in the cylindrical vibration isolator according to this aspect, since the surface area of the stopper rubber is increased, the surface stress accompanying an increase in the input load can be reduced, and the occurrence of cracks can be prevented, thereby improving the durability. It is done.
[0013]
In this aspect, the difference in protrusion height between the central portion of the protruding front end surface of the stopper rubber and the pair of front end protruding portions is appropriately determined according to the required stopper characteristics and the like, and is limited. It is not something. In addition, the specific shape of the pair of tip protrusions is not particularly limited, but for example, it can be advantageously formed as a bowl shape as a whole extending in the axial direction with an arcuate chevron cross-sectional shape. Furthermore, it is desirable that the protruding tip end portion of the stopper rubber including the pair of tip convex portions be tapered as a whole, thereby further reducing the initial spring characteristics and further improving the durability. .
[0014]
Further, according to a second aspect of the present invention, in the cylindrical vibration isolator according to the first aspect, each of the pair of constraining convex portions on the projecting tip surface positioned opposite to the inner shaft member, The shock absorbing rubber layer is formed, and the protruding height of the shock absorbing rubber layer toward the inner shaft member is smaller than the central portion of the protruding front end surface of the stopper rubber. In this embodiment, as the input load increases, after the stopper rubber is brought into contact with the inner shaft member and elastically deformed by a predetermined amount, the buffer rubber is applied to the inner shaft member. It will be touched. As a result, when the input load increases, the pressure receiving area with which the inner shaft member contacts the stopper mechanism is such that the pressure receiving area of the buffer rubber is added to the pressure receiving area of the stopper rubber. As a result, the stepwise nonlinear spring characteristic is realized, and the relative displacement amount of the inner shaft member and the outer cylinder member can be more reliably and buffered while ensuring the soft initial spring characteristic. It becomes.
[0015]
Furthermore, a third aspect of the present invention is the cylindrical vibration isolator according to the first or second aspect, wherein the outer rubber is positioned between the pair of restraining convex portions and supports the stopper rubber. The inner circumferential surface of the cylindrical member extends linearly in the circumferential direction with a predetermined width. Ruhei It is characterized by having a carrier surface shape. In this embodiment, it is possible to advantageously form a support surface for the stopper rubber in the outer cylinder member, and it is also possible to advantageously secure a volume that can function as the stopper rubber in the circumferential direction.
[0016]
According to a fourth aspect of the present invention, in the cylindrical vibration isolator according to any one of the first to third aspects, the outer peripheral surface of the inner shaft member is cylindrical, and the inner shaft member The outer peripheral surface is covered with the main rubber elastic body over the entire circumference. In this embodiment, since the stopper rubber is brought into contact with the main rubber elastic body covering the inner shaft member, the spring characteristic of the main rubber elastic body can also be used for the stopper characteristics. Accordingly, even if the rubber volume of the stopper rubber is small, the initial spring characteristics can be set softly. In particular, since the outer peripheral surface of the inner shaft member has a cylindrical shape, the thickness of the main rubber elastic body covering the inner shaft member is further increased at the portion where the pair of front end convex portions of the stopper rubber are brought into contact with each other. It can be advantageously secured.
[0017]
Furthermore, a fifth aspect of the present invention is the cylindrical vibration damping device according to any one of the first to fourth aspects, wherein the outer cylindrical member is provided with an axial dimension of a tip portion of the stopper rubber. It is characterized in that it is smaller than the axially opposed width dimension at the tip portion of the pair of restraining convex portions. In this embodiment, the entire tip portion formed on the stopper rubber is projected between the pair of restraining convex portions, and the effective dimension in the load input direction is set large in the whole tip portion. Therefore, the initial spring characteristic at the time of contact of the tip portion with the inner shaft member side can be set to be softer.
[0018]
The sixth aspect of the present invention provides the first to the second aspects. Five In the cylindrical vibration isolator according to any one of the aspects, the stopper rubber may be the main rubber elastic body. German It is characterized by being formed upright. In this aspect, the presence of the stopper rubber and the influence on the main rubber elastic body due to its elastic deformation can be avoided, and the original vibration-proof performance in the cylindrical vibration-proof device can be stably exhibited. The stopper rubber only needs to be in a state in which the transmission of stress to and from the main rubber elastic body is avoided. For example, the stopper rubber is formed completely independently from the main rubber elastic body. It is also possible to integrally vulcanize and mold the main rubber elastic body and the stopper rubber with a structure in which they are connected to each other by a thin covering rubber layer covering the inner peripheral surface.
[0019]
Furthermore, a seventh aspect of the present invention is the first to the second aspect. Six In the cylindrical vibration isolator according to any one of the above, the stopper rubber protrudes from only one side of the pair of lightening holes, and the inner shaft member is opposed to the outer cylinder member. It is eccentrically positioned on the opposite side of the stopper rubber in the direction perpendicular to the axis that is the protruding direction of the stopper rubber, and the main rubber elastic body is in the direction perpendicular to the axis. At V The main rubber elastic body is constituted by a pair of elastic connecting legs each having a letter-shaped cross-sectional shape and extending from the inner shaft member to both sides in the circumferential direction sandwiching the stopper rubber. According to this aspect, since the inner shaft member is positioned eccentrically with respect to the outer cylindrical member on the side opposite to the stopper rubber disposition direction, the hole in which the stopper rubber is disposed is provided. With a large cross-sectional shape, it is possible to more advantageously secure the rubber volume of the stopper rubber. In addition, according to this aspect, it is possible to advantageously realize a cylindrical vibration isolator that is subjected to a static initial load in a mounted state, such as an engine mount for an automobile.
[0020]
An eighth aspect of the present invention is the cylindrical vibration isolator according to any one of the first to seventh aspects, wherein the outer cylindrical member is made of a synthetic resin, and the main rubber elastic body and the By molding the outer cylindrical member with the surface of the main rubber elastic body as a part of the molding surface in the presence of the stopper rubber, the main rubber elastic body and the stopper rubber are simultaneously formed with the outer cylindrical member. It is characterized by being assembled to the cylindrical member. In this aspect, the main rubber elastic body and the stopper rubber can be easily assembled to the outer cylinder member, and particularly, the rubber elastic body and the stopper rubber are fitted between the pair of restraining convex portions in the outer cylinder member. In this state, the stopper rubber can be easily assembled. In this aspect, preferably, a stopper rubber integrally formed with the main rubber elastic body is employed, and a covering rubber layer covering the inner peripheral surface of the outer cylinder member over the entire circumference is provided. The main rubber elastic body and the stopper rubber are integrally formed.
[0021]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, in order to clarify the present invention more specifically, embodiments of the present invention will be described in detail with reference to the drawings.
[0022]
First, FIGS. 1 to 3 show an automobile engine mount 10 that is a cylindrical vibration isolator as one embodiment of the present invention. The engine mount 10 has an inner cylinder member 12 as an inner shaft member and an outer cylinder member 14 as an outer cylinder member spaced apart on the outer peripheral side of the inner cylinder member 12 elastically by a main rubber elastic body 16. Vibrations exerted between the inner and outer cylinder members 12 and 14 mainly in the direction perpendicular to the vertical axis in FIG. 1 by being interposed between an automobile body and a power unit (not shown). The anti-vibration effect effective against the above can be demonstrated. In the following explanation, the vertical direction means the vertical direction in FIG. 1 in principle.
[0023]
More specifically, the inner cylinder member 12 is formed of a metal tube and has a straight thick cylindrical shape. Further, an outer cylinder member 14 is disposed in the outer peripheral area of the inner cylinder member 12 so as to be spaced outward in the radial direction. The outer cylinder member 14 is formed of, for example, a synthetic resin material such as a fiber reinforced polyamide resin, and has a thick, substantially cylindrical body extending over the entire circumference in the circumferential direction with a substantially constant width. A portion 18 is provided.
[0024]
In the present embodiment, the bottom portion 20 of the main body cylinder portion 18 has a flat shape, and the inner peripheral surface of the bottom portion 20 is a stopper support surface 22 that extends substantially orthogonally to the main vibration input direction. ing. The main body cylinder portion 18 has a substantially line-symmetric shape on both the left and right sides with a single radial line extending in the vertical direction in FIG. 1 as the main vibration input direction as the axis of symmetry.
[0025]
In addition, a pair of constraining convex portions 24 and 24 projecting on the inner peripheral surface toward the inner cylindrical member 12 are integrally formed on the main body cylindrical portion 18 at both side portions of the bottom portion 22 in the axial direction. A recess 26 that extends linearly in the circumferential direction with a predetermined width on the bottom 22 is formed between the opposing surfaces of the pair of constraining convex portions 24, 24. The constraining convex portions 24, 24 are integrally formed with a predetermined length in the circumferential direction only at the central portion in the circumferential direction of the bottom portion 22, and both circumferential end portions of the recess 26 are open on both sides in the axial direction on the bottom portion 22. Has been. Each constraining convex portion 24 has a substantially constant height over the entire length in the circumferential direction, and the protruding tip surface 23 has a flat surface shape extending in the circumferential direction with a predetermined axial width. Furthermore, the opposing surfaces in the axial direction of the both restraining convex portions 24, 24 are gradually expanded toward the inner cylinder member 12, and the distance between the opposing surfaces is gradually increased toward the projecting tip side of the restraining convex portions 24, 24. It becomes the inclined surface 25 which becomes.
[0026]
Furthermore, the outer cylinder member 14 is integrally formed with a pair of mounting leg portions 28, 28 that extend obliquely downward from both axial end surfaces of the bottom portion 20 of the main body cylindrical portion 18 and expand outward in the axial direction. A metal sleeve 30 for inserting a bolt is assembled to both the mounting legs 28, 28 in a penetrating state in the thickness direction.
[0027]
The inner cylinder member 12 is inserted into the hollow interior of the main body cylinder portion 18 with respect to the outer cylinder member 14 as described above, and is eccentrically positioned upward by a predetermined amount with respect to the central axis of the main body cylinder portion 18. I'm hurt.
[0028]
Thus, the main rubber elastic body 16 is interposed between the inner cylinder member 12 and the outer cylinder member 14 (main body cylinder portion 18), and the inner rubber member 16 and the outer cylinder are interposed by the main rubber elastic body 16. The member 14 is elastically connected. The main rubber elastic body 16 has an approximately V-shaped cross section extending in the axial direction and extends in the axial direction as a whole, and the inner cylinder member 12 is disposed to penetrate the central bent portion of the V-shape. While the body 16 is vulcanized and bonded to the outer peripheral surface of the inner cylinder member 12, both V-shaped tip portions are fixed to the inner peripheral surface of the main body cylinder portion 18 of the outer cylinder member 14. The intermediate portion of the inner cylinder member 12 in the axial direction is embedded in the main rubber elastic body 16, and the outer peripheral surface of the inner cylinder member 12 is covered by the main rubber elastic body 16 over the entire circumference. .
[0029]
In other words, the main rubber elastic body 16 is constituted by a pair of elastic connecting legs 32 and 32 extending from the inner cylinder member 12 toward the outer cylinder member 14, respectively. The pair of elastic connecting legs 32, 32 extend obliquely downward with a predetermined center angle that expands toward the opposite side (downward direction in FIG. 1) of the inner cylinder member 12 with respect to the outer cylinder member 14. The left and right sides are substantially line-symmetrical with one radial line extending in the vertical direction passing through the central axis of the inner cylinder member 12 as the axis of symmetry. In each of the elastic connecting legs 32, 32, the wall thickness around the central axis of the inner cylinder fitting 12 is gradually reduced from the inner cylinder member 12 to the outer cylinder member 14.
[0030]
On the other hand, on the inner peripheral surface of the main body cylinder portion 18 of the outer cylinder member 14, the inner peripheral surface of the main body cylinder portion 18 extends substantially continuously with a substantially constant thickness over the entire circumference. A covering rubber layer 34 covering the entire surface is formed and fixed, and the outer end portions of the elastic connecting legs 32, 32 constituting the main rubber elastic body 16 are integrated with the covering rubber layer 34. It is connected to. In short, the main rubber elastic body 16 is integrally formed with the covering rubber layer 34.
[0031]
Thereby, between the inner cylinder member 12 and the outer cylinder member 14, an upper side wall hole 36 and a lower side wall hole 38 that extend in the axial direction are provided on both upper and lower sides sandwiching the main rubber elastic body 16. ing. A rebound stopper 40 that protrudes upward from the inner cylinder member 12 toward the outer cylinder member 14 is disposed in the upper side hollow hole 36. The rebound stopper 40 is integrally formed with the main rubber elastic body 16 and is formed in the central portion of the inner cylinder member 12 in the axial direction so as to extend in a predetermined length in the axial direction with a substantially chevron cross section.
[0032]
On the other hand, a bound stopper 42 as a stopper rubber that protrudes upward from the outer cylinder member 14 toward the inner cylinder member 12 is disposed in the lower side wall 38. The bound stopper 42 is integrally formed with a covering rubber layer 34 that covers the inner peripheral surface of the main body cylinder portion 18 of the outer cylinder member 14. In short, in the present embodiment, the main rubber elastic body 16 is formed as an integrally vulcanized molded product including the covering rubber layer 34, the rebound stopper 40, and the bound stopper 42. The covering rubber layer 34 that covers the inner peripheral surface of the main body cylindrical portion 18 extends to the protruding tip surfaces 23 and 23 of the pair of restraining convex portions 24 and 24 that protrude from the main body cylindrical portion 18. As a result, a buffer rubber layer 44 is formed on the projecting tip surfaces 23 and 23 of the constraining convex portions 24 and 24 so as to expand in a substantially integral thickness.
[0033]
The bound stopper 42 has a circumferential length that is slightly shorter than the stopper support surface 22 at the center portion in the circumferential direction of the stopper support surface 22 formed on the bottom 20 of the main body cylindrical portion 18. The protruding height of the bound stopper 42 is set to be larger than the protruding height of the restraining convex portions 24, 24 protruding from the bottom portion 20. As a result, the base end portion of the bound stopper 42 is positioned in a state of being embedded in the recess 26 between the constraining convex portions 24, 24, and the bottom surface (stopper support surface 22) or constraining convex portion of the recess 26. 24, 24 is fixed to the inclined surfaces 25, 25, while the tip portion of the bound stopper 42 protrudes from the recess 26 between the constraining projections 24, 24 into the lower side wall 38, and the inner cylinder It extends toward the member 12. As apparent from FIG. 2, the bound stopper 42 protrudes into the lower side wall 38 with an axial dimension smaller than the distance between the opposing surfaces at the upper end opening of the pair of restraining convex portions 24, 24. Yes.
[0034]
Furthermore, the outer peripheral surface of the bound stopper 42 is axially oriented so that the portion projected from the recess 26 between the constraining convex portions 24, 24 has a tapered shape as it goes toward the projecting tip side in the axial direction and circumferential direction. And is inclined in the circumferential direction. Further, the protruding front end surface of the bound stopper 42 has the same or slightly smaller dimension as the bottom surface of the recess 26 in the axial direction, and has a slightly smaller dimension than the constraining convex portions 24 and 24 in the circumferential direction. The main rubber elastic body 16 is opposed to the embedded portion of the inner cylinder member 12 at a predetermined distance in the vertical direction.
[0035]
In addition, a pair of tip protrusions 46, 46 having a generally arcuate shape and extending in the axial direction with a constant cross-sectional shape at both end portions in the circumferential direction are formed on the protruding tip surface of the bound stopper 42, It is integrally formed. The central portion in the circumferential direction of the protruding tip surface of the bound stopper 42 is positioned between the pair of tip protrusions 46, 46, thereby forming a valley-shaped central valley portion 48. The protrusion heights of the tip protrusions 46 and 46 formed on both sides in the circumferential direction are made larger than the protrusion height.
[0036]
As shown in FIG. 1, the projecting vertices of the tip protrusions 46 and 46 are positioned so as to overlap the inner cylinder member 12 in the vertical projection that is the main vibration input direction. ing. Further, the central valley portion 48 is set at a position that protrudes toward the inner cylinder member 12 by a predetermined amount from the surface of the cushioning rubber layer 44 formed on the restraining convex portions 24, 24 of the outer cylinder member 14. .
[0037]
By the way, the engine mount 10 having the above-described structure is formed by separately forming an integrally vulcanized molded product of the main rubber elastic body 16 vulcanized and bonded to the inner cylinder member 12 and the outer cylinder member 14. After the caulking, it is possible to attach the main rubber elastic body 16 to the outer cylinder member 14 for adhesion, but preferably, for example, (a) in the molding cavity of the vulcanization mold of the main rubber elastic body 16 In a state where the separately manufactured inner cylinder member 12 and outer cylinder member 14 are positioned and set, the molding cavity is filled with a predetermined rubber material, and the main rubber elastic body 16 is vulcanized and molded at the same time. , 14 and vulcanized and bonded, or (b) the main rubber elastic body 16 vulcanized and molded into the inner cylinder member 12 in advance in the molding cavity of the resin mold of the outer cylindrical member 14. Integrated vulcanization In a state where the product is positioned and set, a method of filling the molding cavity with a predetermined resin material, and bonding the main rubber elastic body 16 to the outer cylinder member 14 and assembling simultaneously with the molding of the outer cylinder member 14, etc. Adopted. In particular, according to the manufacturing method of the latter (b), it is possible to reduce or eliminate the generation of tensile stress due to vulcanization shrinkage of the main rubber elastic body 16 and improve durability.
[0038]
The engine mount 10 having the above-described structure is not clearly shown in the drawing, but the mounting legs 28 and 28 of the outer cylinder member 14 are attached to the body of the automobile by bolts inserted into the metal sleeve 30. On the other hand, the inner cylinder member 12 is fixed between the power unit and the body of the automobile by being fixed to the power unit of the automobile by the rod inserted through the center hole thereof. Against vibration isolation. Under such a mounted state, the main rubber elastic body 16 is elastically deformed by a predetermined amount due to the static shared support load of the power unit exerted between the inner and outer cylinder members 12 and 14 in the vertical direction. Thus, the inner and outer cylinder members 12, 14 are positioned substantially on the same axis.
[0039]
Further, under such a mounted state, the bounce stopper 42 and the rebound stopper 40 and the main rubber elastic body 16 and the outer cylinder member 14 on the inner cylinder member 12 that are opposed to each other in the vertical direction with respect to the protruding tip surfaces thereof. In any case, a predetermined amount of gap is present between the covered rubber layers 34. When a large vibration load is input when the vehicle travels and the inner and outer cylindrical members 12 and 14 are relatively displaced in the vertical direction as the main rubber elastic body 16 is elastically deformed, the bound stopper 42 is moved to the inner cylindrical member 12. The bounce direction and the rebound direction in the inner and outer cylinder members 12, 14 by being brought into contact with the upper main rubber elastic body 16 or by being brought into contact with the covering rubber layer 34 on the outer cylinder member 14. The relative displacement amount is limited in a buffering manner.
[0040]
Here, since the bound stopper 42 is restrained on both sides in the axial direction by a pair of restraining convex portions 24, 24, the stopper in the outer cylinder member 14 is suppressed while suppressing an excessive amount of elastic deformation and distortion when a large load is input. The protrusion height dimension from the support surface 22 can be set large, and thereby the spring characteristic at the initial contact of the bound stopper 42 to the inner cylinder member 12 side can be set sufficiently soft, By setting a large spring stiffness that is exhibited when a large vibration load is input, the relative displacement amount of the inner and outer cylinder members 12 and 14 can be reliably and stably limited. -A stopper mechanism that can advantageously realize a deflection characteristic, that is, a non-linear spring characteristic, has no shock feeling or a hitting sound, and can exert an effective displacement amount limiting effect. It's revealed that may be.
[0041]
In addition, in the bound stopper 42, the inner cylinder member 12 is spaced from the inner cylinder member 12 at a position spaced apart on both sides in the circumferential direction from the central valley portion 48 that is opposed to the inner cylinder member 12 on the main axis of vibration input. The tip protrusions 46 and 46 positioned opposite to each other are protruded largely toward the inner cylinder member 12 side, and the tip protrusions 46 and 46 are more than the central valley portion 48 when vibration is input. Thus, the main rubber elastic body 16 on the inner cylinder member 12 side is first brought into contact with the main cylindrical rubber member 16 with a small input load. Therefore, by compressing and deforming both end protrusions 46, 46, an effective compressive force is generated in the bounce stopper 42 at both sides in the circumferential direction. It is exerted as a compressive force also on the central portion in the direction.
[0042]
Therefore, even when the bound stopper 42 is greatly compressed and deformed, the stress generated in the bound stopper 42 is easily dispersed as a whole, and the circumferential direction in which the bound stopper 42 is intensively generated with respect to the central portion in the circumferential direction. The tensile stress on both sides can be reduced or eliminated. As a result, the load bearing strength and durability of the bound stopper 42 can be advantageously improved.
[0043]
In addition, since the protruding vertices of the pair of tip protrusions 46 and 46 in the bound stopper 42 are formed so as to overlap the inner cylinder member 12 in the load input direction, the bounding through the tip protrusions 46 and 46. A compressive load can be efficiently applied to the stopper 42, and the tip protrusions 46, 46 are prevented from being collapsed in the circumferentially spaced direction, and the above-described based on the compressive deformation of the both tip protrusions 46, 46. Thus, the effect of reducing the tensile stress of the central valley portion 48 can be more effectively exhibited.
[0044]
In addition, the bounce stopper 42 has a corrugated surface with an uneven surface on the inner cylinder member 12 side by a pair of tip protrusions 46, 46 and a central valley 48, and its surface area is increased. Therefore, the surface stress of the bound stopper 42 caused by the contact with the inner cylinder member 12 side is reduced, thereby preventing the occurrence of cracks in the bound stopper 42 and improving the durability. It can be achieved effectively.
[0045]
Further, in the present embodiment, since the outer peripheral surface of the inner cylinder member 12 is cylindrical, it is formed by the main rubber elastic body 16 that covers the inner cylinder member 12, and the tip protrusions 46 of the bound stopper 42, The rubber thickness at the abutted portion on the inner cylinder member 12 side on which the abutment 46 is abutted can be advantageously ensured, whereby the initial spring characteristics upon the abutment of the bound stopper 42 can be determined by the protrusion height of the bound stopper 42. It is possible to set more softly without increasing the size.
[0046]
Furthermore, in this embodiment, when a large vibration load is input, the inner cylindrical member 12 side first abuts against the tip protrusions 46, 46 of the bound stopper 42, and then the central valley portion 48 is crushed so that the bound stopper 42 abuts substantially over the front end of the projecting tip surface, and then abuts against the restraining convex portions 24, 24 via the cushioning rubber layers 44, 44, thereby softening initially. As the input load increases, the objective stopper mechanism that becomes non-linearly hard and finally can reliably regulate the relative displacement amount of the inner and outer cylinder members 12, 14 can be realized more advantageously. .
[0047]
As mentioned above, although embodiment of this invention was explained in full detail, this is an illustration to the last, Comprising: This invention is not limited at all by the specific description in this embodiment.
[0048]
For example, in the above-described embodiment, only the stopper mechanism in the bound direction is configured by the stopper rubber according to the present invention. However, in addition to the stopper mechanism in the bound direction or instead of the stopper mechanism in the bound direction, the stopper in the rebound direction. It is of course possible to configure the mechanism with a stopper rubber according to the invention.
[0049]
Further, in the above embodiment, the constraining convex portions 24, 24 are formed with a predetermined length only in the central portion of the bottom portion 20 of the main body cylindrical portion 18 in the outer cylinder member 14. The direction length, the protrusion height, and the like are appropriately changed according to the required characteristics of the stopper mechanism, and are not limited. Specifically, for example, as shown in FIGS. 4 to 5, the constraining convex portions 24, 24 are formed over the entire length of the bottom portion of the main body cylindrical portion 18, and the base end portion of the bound stopper 42 is substantially in the circumferential direction. It is also possible to adopt a configuration that is constrained over the whole, and according to such a configuration, it is possible to further increase the rise of the spring characteristics by the bound stopper 42 and to further improve the durability. 4 to 5, in order to facilitate understanding thereof, the same reference numerals as those of the above embodiment are given to members and parts having the same structure as that of the above embodiment. Keep it. Moreover, since the longitudinal cross-sectional view in the engine mount shown by FIGS. 4-5 is represented substantially the same as the longitudinal cross-sectional view of the said embodiment, illustration is abbreviate | omitted.
[0050]
Further, in the above embodiment, the main rubber elastic body 16 having an approximately V-shaped cross section and extending in the axial direction has been adopted. However, the specific shape of the main rubber elastic body is required to have vibration-proof characteristics and load resistance performance. It is determined appropriately in consideration of the above, and is not limited. Specifically, for example, the inner and outer cylinder members 12 and 14 are arranged on the same central axis, and the inner cylinder member 12 is sandwiched between the opposing surfaces of the inner and outer cylinder members 12 and 14 in one diametrical direction. It is also possible to adopt a main rubber elastic body having a linearly extending cross-sectional shape, and such a main rubber elastic body is a static initial load exerted in a mounted state such as a suspension bush or an engine roll mount. Can be advantageously employed when is very small or substantially zero.
[0051]
Further, in the embodiment, the metal inner cylinder member and the synthetic resin outer cylinder member are employed, but the material of the inner and outer cylinder members is not limited, and the required strength, characteristics, use conditions, etc. are taken into consideration. And can be selected appropriately.
[0052]
Further, the mounting leg portions 28 and 28 in the outer cylinder member 14 are not necessarily required. For example, an outer cylinder member having a cylindrical outer peripheral surface is adopted to be used as a mounting hole such as an arm eye in an automobile suspension mechanism or the like. It is also possible to press-fit and assemble the outer cylinder member.
[0053]
Furthermore, in the above-described embodiment, the pair of constraining convex portions 24, 24 are integrally formed with the main body cylinder portion 18 of the outer cylinder member 14. However, these constraining members are formed separately from the outer cylinder member 14, and the main body cylinder It can also be formed by being fixed to the portion 18 afterward.
[0054]
In addition, in the above-described embodiment, a specific example of applying the present invention to an engine mount for automobiles has been shown. However, the present invention can be applied to body mounts, differential mounts, suspension bushings for automobiles, and various types other than automobiles. Any can be applied to the cylindrical vibration isolator used in the apparatus.
[0055]
In addition, although not enumerated one by one, the present invention can be carried out in a mode to which various changes, modifications, improvements and the like are added based on the knowledge of those skilled in the art. It goes without saying that all are included in the scope of the present invention without departing from the spirit of the present invention.
[0056]
【The invention's effect】
As is clear from the above description, in the cylindrical vibration isolator constructed according to the present invention, when a large load is input and the stopper rubber is brought into contact with the inner shaft member side, the periphery of the stopper rubber is A pair of tip projections projecting on both sides in the direction are brought into contact with the inner shaft member, and an effective compressive force is exerted on both sides in the circumferential direction of the stopper rubber. By acting so as to reduce the tensile force generated in the circumferential intermediate portion, the bursting damage in the circumferential intermediate portion of the stopper rubber can be effectively reduced or avoided, whereby the stopper Excellent load-bearing performance and durability can be realized in rubber, and thus in vibration isolator.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view showing an engine mount as an embodiment of the present invention.
FIG. 2 is a cross-sectional view taken along the line II-II in FIG.
FIG. 3 is a left side view in FIG. 2;
FIG. 4 is a left side view corresponding to FIG. 3, showing an engine mount as another embodiment of the present invention.
5 is a cross-sectional view corresponding to FIG. 1, showing the engine mount shown in FIG. 4;
[Explanation of symbols]
10 Engine mount
12 Inner cylinder member
14 Outer cylinder member
16 Body rubber elastic body
18 Body cylinder
22 Stopper support surface
24 Constrained convex part
26 recess
32 Elastic connecting legs
34 Coated rubber layer
36 Upper side hole
38 Lower side hole
40 Rebound stopper
42 Bound stopper
44 Buffer rubber layer
46 Tip protrusion
48 Chuo Valley

Claims

An inner shaft member having a cylindrical outer peripheral surface, relative to the outer tubular member which is spaced on the outer peripheral side of the inner shaft member, is allowed to intervene between the axis-perpendicular direction facing surface thereof the inner shaft member and the outer tubular member The main rubber elastic body is directly vulcanized and bonded to elastically connect the inner shaft member and the outer cylinder member with the main rubber elastic body, and on both sides in the direction perpendicular to the axis across the inner shaft member, The inner shaft member and the outer cylinder member are each provided with a pair of lightening holes extending in the axial direction, and further positioned at at least one of the pair of lightening holes from the outer cylinder member to the inner shaft member. A stopper rubber that protrudes toward the inner side of the stopper rubber and protrudes at a height smaller than the stopper rubber from the outer cylindrical member toward the inner shaft member on both axial sides of the stopper rubber. In cylindrical vibration damping device provided with a pair of restraining protrusions for restraining the proximal portion of the arm from both axial sides,
A protruding tip surface of the stopper rubber protrudes on both sides in the circumferential direction from the central portion, and a pair of tip protrusions are formed integrally with the stopper rubber, and each vertex of the pair of tip protrusions is formed in the protruding direction of the stopper rubber. The circumferential separation distance between the vertices is smaller than the width dimension in the direction perpendicular to the axis of the inner shaft member so as to overlap the cylindrical outer peripheral surface of the inner shaft member in projection at Shaker.

A cushioning rubber layer is formed on each of the pair of constraining convex portions on the projecting front end face facing the inner shaft member, and the projecting height of the buffer rubber layer toward the inner shaft member is The cylindrical vibration isolator according to claim 1, which is smaller than a central portion of a protruding tip surface of the stopper rubber.

The pair of being brought located between restraining protrusions, the inner peripheral surface of the outer tubular member and stopper rubber supporting, according to claim 1 or a flat Tanmen shape Ru extending linearly in the circumferential direction at a predetermined width 2. The cylindrical vibration isolator according to 2.

4. The outer peripheral surface of the inner shaft member has a cylindrical shape, and the outer peripheral surface of the inner shaft member is covered over the entire periphery by the main rubber elastic body. 5. Cylindrical anti-vibration device.

The axial dimension of the front-end | tip part in the said stopper rubber is made smaller than the axial direction opposing width dimension in the front-end | tip part of the said pair of restraint convex part provided in the said outer cylinder member. Cylindrical vibration isolator.

The stopper rubber, cylindrical vibration damping device according to any one of claims 1 to 5 is formed with the main rubber elastic body or RaDoku standing.

The stopper rubber protrudes only on one side of the pair of cutout holes, and the inner shaft member extends in a direction perpendicular to the axis that is the protrusion direction of the stopper rubber with respect to the outer cylinder member. A pair of elastic members that are eccentrically positioned on the opposite side, have a V- shaped cross-sectional shape in the direction perpendicular to the axis of the main rubber elastic body, and extend from the inner shaft member to both sides in the circumferential direction with the stopper rubber interposed therebetween. The cylindrical vibration isolator according to any one of claims 1 to 6, wherein the main rubber elastic body is constituted by a connecting leg portion.

The outer cylinder member is formed of a synthetic resin material, and the outer cylinder member is molded using the surface of the main rubber elastic body as a part of the molding surface in the presence of the main rubber elastic body and the stopper rubber. The cylindrical vibration isolator according to any one of claims 1 to 7, wherein the main rubber elastic body and the stopper rubber are assembled to the outer cylinder member simultaneously with the molding of the outer cylinder member.