JP4126597B2

JP4126597B2 - Liquid seal vibration isolator

Info

Publication number: JP4126597B2
Application number: JP2002264361A
Authority: JP
Inventors: 和俊佐鳥; 徹坂本
Original assignee: Yamashita Rubber Co Ltd
Current assignee: Yamashita Rubber Co Ltd
Priority date: 2002-05-20
Filing date: 2002-09-10
Publication date: 2008-07-30
Anticipated expiration: 2022-09-10
Also published as: JP2004044774A

Description

【０００１】
【発明の属する技術分野】
この発明はエンジンマウント等に使用する液封防振装置であって、主たる振動の入力方向（以下、これをＺ軸方向及び縦方向という）における入力振動を主として防振する縦方向防振部と、Ｚ軸方向と直交する方向（以下、これをＸ・Ｙ軸方向及び横方向という）の入力振動を主として防振する横方向防振部とを一体化し、縦方向及び横方向のいずれの方向からの入力振動にも対応できるようにした液封防振装置に係り、特に、液室の内圧を制御することにより、入力振動に応じてバネ特性及び減衰特性を可変にしたものに関する。
【０００２】
【先行技術】
振動発生側へ取付けられる第１の取付部材と、振動受け側へ取付けられる第２の取付部材と、これら第１の取付部材と第２の取付部材を連結する略円錐状をなす弾性体本体部材とを備え、弾性本体部の内側にこの弾性本体部を弾性壁部の一部とする液室を設け、この液室を仕切り部材により２つに区画して両液室を第１のオリフィス通路で連絡することにより、Ｚ軸方向に主液室と副液室を配設した円錐型マウントは周知である。また、円筒状の内外筒間を弾性部材で連結するとともに、内外筒間を弾性部材によって周方向へ区画された複数の液室を設け、これらの液室間をオリフィス通路で結んだ円筒ブッシュも周知である。
【０００３】
さらに、このような円筒型ブッシュと円錐型マウントを複合一体化してエンジンマウントとした液封防振装置は公知である。このようにすると、主たる振動を円錐マウント部で吸収し、これに直交する方向の振動を円筒型ブッシュ部で吸収できるので、単一装置で直交する３軸、ＸＹＺ軸方向、すなわち縦及び横方向のすべての振動を吸収可能になる。このような構造の例として、特公昭６３−６１５３３、特開昭６１−２６２２４４、特開２００２−２１９１４、特開２００１−３４９３６９、特開２００２−３９３５５、特開２００２−８９６１３、特開２００２−９８１５５、特開２００２−１２２１７５がある。
また、縦方向振動部における液室に臨む弾性壁の一部を弾性変形可能な弾性膜とし、この弾性変形を制御することにより、液室内の内圧を制御する内圧制御手段を設けたものも種々公知である。このような構造の例として、特開平１０−３８０１７、特開平１０−２８１２１４、特開２００２−０７０９３１がある。
さらに、縦方向振動部における液室に臨む弾性壁の一部を薄肉にしてその膜共振を利用することにより低動バネ化させるとともにその範囲をブロード化することも公知である。このような構造の例として、特開平１１−３５１３１１がある。
【０００４】
【発明が解決しようとする課題】
ところで、上記のような縦方向防振部と横方向防振部を一体化したものであっても、それぞれの部分において入力振動に対応して発生する内圧は弾性部材の形状等によって決まってしまうから、バネ特性や減衰特性も入力振動に応じて決まってしまう。しかし液室の内圧を制御できれば、共振効率を大きくしたいときは内圧を上げ、逆に低動バネを必要とするときには内圧を下げることにより、バネ特性や減衰特性を入力振動に応じて最適に変化させることが可能になる。
【０００５】
このような内圧制御は縦方向防振部においては上記に例示したように公知であるが、縦方向防振部と横方向防振部を複合一体化した液封防振装置において、縦方向並びに横方向のいずれでもこのような内圧制御を行おうとすれば、縦方向防振部と横方向防振部のそれぞれに内圧制御手段を設けなければならず、装置の複雑・大型化並びにコストの大幅アップを招くことになる。
【０００６】
そこで、縦方向防振部と横方向防振部を複合一体化した防振装置において、縦方向並びに横方向いずれの振動に対しても内圧制御でき、しかも装置の簡単・小型化並びにコストダウンを可能にすることが望まれることになる。本願発明は係る要請の実現を目的とする。
【０００７】
【課題を解決するための手段】
上記課題を解決するため請求項１に係る液封防振装置は、主たる振動を主として防振する縦方向防振部と、主たる振動の入力方向と直交する方向の振動を主として防振する横方向防振部とを一体化した液封防振装置であって、縦方向防振部は主たる振動の入力方向に、弾性部材と、この弾性部材を壁の一部とする縦主液室と、この縦主液室にオリフィス通路を介して連通する縦副液室とを配設し、横方向防振部は主たる振動の入力方向と直交する平面内に複数の横液室を配置してこれら横液室間をオリフィス通路で連通したものにおいて、前記縦方向防振部の縦主液室を構成する弾性壁が前記横方向防振部の各液室を構成する弾性壁の一部をなすとともに、前記横方向防振部を構成する横液室の少なくとも一つに、その内圧を制御するための内圧制御手段を設けたことを特徴とする。
【０００８】
また、前記内圧制御手段は、前記横液室の内圧変動によって弾性変形する可動膜と、この可動膜の変形を規制する可動膜ストッパとを備え、前記可動膜を自由に弾性変形するフリー状態又は前記可動膜ストッパ上へ固定する拘束状態に切り換えることを特徴とする。
【０００９】
請求項２は上記請求項１において、前記可動膜ストッパは、前記可動膜の非拘束状態において、前記可動膜を当接させてそのバネ定数を変化させることにより前記可動膜に非線形のバネ特性を与えることを特徴とする。
【００１０】
請求項３は上記請求項１において、前記内圧制御手段は、前記可動膜と可動膜ストッパ間に形成される作動室を大気又は吸気負圧に切り換えることにより制御するものであることを特徴とする。
【００１１】
請求項４は上記請求項１において、前記内圧制御手段は、前記可動膜をソレノイド又はモーターにより駆動して制御するものであることを特徴とする。
【００１２】
請求項５は上記請求項１〜４のいずれかにおいて、前記可動膜が前記横液室を構成する他の弾性部材と別体に形成されていることを特徴とする。
【００１４】
請求項６は上記請求項１において、前記横方向防振部における前記オリフィス通路は、少なくとも共振周波数の異なる第１及び第２のオリフィス通路を備えることを特徴とする。
【００１５】
請求項７は上記請求項１において、前記縦方向防振部及び横方向防振部の各液室を構成する弾性壁のうち少なくとも一部の液室を構成する弾性壁の厚さを他の液室を構成する弾性壁の厚さと異ならせたことを特徴とする。
【００１６】
【発明の効果】
請求項１によれば、横方向防振部を構成する複数の横液室の少なくとも一つに内圧制御手段を設けたので、低動バネが要求されるような振動に対しては、内圧制御手段によって横液室の内圧を下げることにより全体を低バネ化する。また、高減衰が要求されるような振動に対しては、内圧制御手段によって横液室の内圧を上げることにより共振効率を高めて高減衰を実現する。
【００１７】
しかも、横方向防振部の横液室を構成する弾性壁の一部を、縦方向防振部の縦主液室を構成する弾性壁となるようにして縦方向防振部と横方向防振部を複合一体化したものであるから、横液室と縦主液室は共通の弾性壁を介して相互に連係し、横液室に対して行う内圧制御の結果が縦主液室に及ぶようになる。したがって、内圧制御手段は横液室の少なくとも一つに設ければ足り、縦方向防振部側への設置を省略できるから、縦方向防振部と横方向防振部を複合一体化した液封防振装置であるにもかかわらず、縦方向並びに横方向いずれの振動に対しても内圧制御でき、しかも装置の簡単・小型化並びにコストダウンが可能になる。
【００１８】
また、内圧制御手段が可動膜と可動膜ストッパを備えるので、低動バネが要求されるような振動に対しては、可動膜をフリー状態にすることによって内圧を吸収させて低動バネ化する。また、高減衰が要求されるような振動に対しては、可動膜ストッパ上へ可動膜を固定して拘束状態とすることにより、横液室の壁剛性を高くして横液室間のオリフィス通路に流入する液量を多くして高減衰を実現する。
【００１９】
請求項２によれば、入力振動が大きくなると可動膜が可動膜ストッパへ当接することにより自由な弾性変形が規制されて可動膜のバネが高くなるので、可動膜が可動膜ストッパへ当接する前後でバネ定数を非線形に変化させることができ、入力振動の大きさに応じて適正なバネ特性を実現できる。
【００２０】
請求項３によれば、可動膜の制御を、大気開放と吸気負圧による吸引の切り換えにより行うようにしたので、可動膜と可動膜ストッパ間に形成される作動室を大気開放すると可動膜をフリー状態とし、吸気負圧で吸引すると、可動膜を可動膜ストッパへ吸着固定して拘束状態にする。したがってエンジンの吸気負圧等を利用して内圧制御手段を容易に実現できる。
【００２１】
請求項４によれば、可動膜の制御をソレノイド又はモーターによる駆動で行うので、これらの電気的駆動制御により内圧制御手段を容易に実現できる。
【００２２】
請求項５によれば、可動膜を横液室を構成する他の弾性部材別体に構成したので、可動膜のみを他の弾性部材と異なる物性材料にでき、必要な部分のみへ最適物性の材料を限定使用できることになり、他の弾性壁を通常の材料のまま使用できるので、全体のコストを抑え、かつ最適性能を得ることができる。
【００２４】
請求項６によれば、横方向防振部におけるオリフィス通路として、少なくとも第１及び第２のオリフィス通路を設け、かつそれぞれの共振周波数を異ならせたから、複数の周波数で液柱共振を発生させるとともに、それぞれの共振効率を向上させることができる。
【００２５】
請求項７によれば、縦方向防振部及び横方向防振部の各液室を構成する弾性壁の少なくとも一部の液室を構成する弾性壁の厚さを他の液室を構成する弾性壁の厚さを異ならせたことにより、膜共振を異なる複数の周波数で発生させることができ、その結果、これら複数の膜共振を連成してより広範囲の周波数域を低動バネ化できる。
【００２６】
【発明の実施の形態】
以下、図面に基づいて車両のエンジンマウントに構成された一実施例を説明する。図１はこのエンジンマウントの全体断面図（図２の１−１線断面図）、図２はＺ軸方向の車体取付時上方となる側から示す平面図、図３は９０°違いの全体断面図（図２の１−３線断面図）、図４は図１の４−４線断面図、図５は第１の取付部と弾性部材が一体化された内挿体の斜視図、図６は内圧制御の説明図、図７〜図１０はバネ特性を示すグラフ、図１１は弾性壁の肉厚変化の組合せを示す略図である。
【００２７】
なお、以下の説明において、図２の図示状態における左右方向、上下方向及び図１における上下方向を、それぞれＸ軸方向、Ｙ軸方向及びＺ軸方向とする。これらのＸ軸方向、Ｙ軸方向及びＺ軸方向は、それぞれ車体取付時の前後方向、左右方向）及び上下方向にも相当する。
【００２８】
これらの図において、このエンジンマウントは円錐型マウントに相当する部分である縦方向防振部１と円筒型ブッシュに相当する部分である横方向防振部２を一体的に形成したものであり、縦方向防振部１は、エンジン側へ取付けられる第１の取付部材３と、その周囲を間隔をもって囲む剛性のある円筒状外枠として構成された第２の取付部材４と、これら第１の取付部材３と第２の取付部材４間を連結する弾性本体部５を有する。
【００２９】
第１の取付部材３は、その軸心方向が縦方向防振部１における主たる振動の入力方向であるＺ軸方向と一致し、弾性本体部５中に埋設されている部分は下方が細径化されＺ軸方向に添って下方へ長く延びる円柱状をなしている。第１の取付部材３の弾性本体部５から上方へ突出する部分は扁平部をなしてエンジンのブラケット（図示省略）に取付けられる。
【００３０】
弾性本体部５の一部である略円錐状のドーム部６によって形成される略円錐型の空間は液室をなし、図１の下方へ開放され、この開放部へ仕切り部材８及びダイアフラム９が取付けられ、ドーム部６の内壁と仕切り部材８の間に形成される部分を縦主液室１０とし、仕切り部材８とダイアフラム９の間を縦副液室１１とし、仕切り部材８により液室内を縦主液室１０と縦副液室１１に区画している。ダイアフラム９はこのエンジンマウントの動特性にとって殆ど無視できる程度の弱いバネを有する可撓性膜部材である。ドーム部６は横液室２０を構成する弾性壁の一部をなし、縦主液室１０と縦副液室１１はＺ軸方向へ並べて配設され、各液室にはそれぞれ公知の非圧縮性液体が封入されている。
【００３１】
仕切り部材８は、適宜樹脂等からなる円筒部１２とこれより小径でかつその内側へ縦副液室１１側から嵌合する押さえプレート１３とで構成され、円筒部１２の外周部に第１のオリフィス通路１５が形成され、縦主液室１０と縦副液室１１を常時連通し、所定の低周波数にて液柱共振を発生して高減衰を実現するダンピングオリフィスとして機能する。仕切り部材８は、縦主液室１０の内圧を吸収する弾性膜８ａを有する。この弾性膜８ａは平面視略円形であり、周囲を円筒部１２と押さえプレート１３の間に固定されている。
【００３２】
円筒部１２と押さえプレート１３の各中央部分は縦主液室１０側へ突出する円形の段部１２ｂ，１３ｂをなし、各段部１２ｂ，１３ｂは弾性膜８ａの上下に所定間隔をもって平行するように設けられ、各々に貫通穴１２ａ及び１３ａが設けられ、弾性膜８ａが縦主液室１０の液圧に応じて弾性変形可能になっている。但し、円筒部１２と押さえプレート１３の段部１２ｂ，１３ｂは弾性膜８ａの中心部８ｂに当接して弾性膜８ａの上下を支持している。これにより、弾性膜８ａは中心部８ｂと外周部の各固定部間における比較的短いスパンで弾性変形して縦主液室１０の内圧を吸収するようになっている。
【００３３】
ドーム部６は、縦主液室１０を覆う弾性壁であって、横方向防振部２は、ドーム部６の上にその外壁を弾性壁の一部とする複数の横主液室（本実施例では前後一対をなす２０Ａ及び２０Ｂ）が形成されている。これら前後の横主液室２０Ａ及び２０Ｂは、それぞれ側方へ開放されて図１に示す断面で略三角形の空間をなすとともに、弾性本体部５と一体に形成されて略水平の前後方向へ広がる前後の端部壁２１Ａ、２１Ｂとドーム部６及び液室カバー２２又は横膜５０で密閉される。
本実施例においては、車体取付時後側となる横主液室（以下、後側横主液室という）２０Ｂに対して液室カバー２２が取付けられ、車体取付時前側となる横主液室（以下、前側横主液室という）２０Ａには横膜５０が取付けられている。
【００３４】
図４に示すように、液室カバー２２は第２の取付部材４の内周面へ略１／４円周の円弧状をなし、後側横主液室２０Ｂへ嵌合されその開口縁部へ密接される。液室カバー２２の第２の取付部材４と接触する外表面には周方向へ延びる溝２３が上下２段に設けられて第２の取付部材４側へ開放され、この溝２３により第２の取付部材４との間にダンピングオリフィス通路２４及びアイドルオリフィス通路２６が形成されている。アイドルオリフィス通路２６は、後側横主液室２０Ｂと横副液室２５を連通している。
【００３５】
横副液室２５は、前後の横主液室２０Ａ，２０Ｂ間に左右一対で設けられたすぐり部２７Ｒ、２７Ｌのうちの一方である左側のすぐり部２７Ｌに対して、その内部をダイアフラム２８で区画することにより形成され、本実施例の場合は、ダイアフラム２８と第２の取付部材４との間に形成される。ダイアフラム２８は縦方向防振部１におけるダイアフラム９と同様の可撓性膜部材である。図中の符号２９はダイアフラム２８の座部に埋設された略四辺形の枠金具であり、ダイアフラム２８の取付時における位置決め並びに横副液室２５を液密にシールすることに役立っている。
【００３６】
横方向防振部２におけるダンピングオリフィス通路２４は前側横主液室２０Ａと入り口３０で通じ、右側のすぐり部２７Ｒを構成する弾性仕切壁３６の外側面に形成された溝３１（図４）及び液室カバー２２の外側面に形成された下側の溝２３を経て横副液室２５と出口（図４にてアイドルオリフィス通路２６の出口３３の下方に重なっている）で通じる。同様にアイドルオリフィス通路２６は後側横主液室２０Ｂと入り口３２で通じ、横副液室２５と出口３３で通じる。出口３３とアイドルオリフィス通路２６は弾性仕切壁３５の外側面に形成された溝３５ａを介して連通する（図４）。
【００３７】
但し、これらダンピングオリフィス通路２４及びアイドルオリフィス通路２６は、互いに長さや通路断面積等の通路特性を異にしており、その結果、ダンピングオリフィス通路２４は一般走行時の低周波振動（例えば、７〜１５Ｈｚ程度）に対して共振点を有し、アイドルオリフィス通路２６はこれよりも高周波数側（例えば、１５〜４０Ｈｚ程度）のアイドル振動に対して共振点を有する。本実施例ではダンピングオリフィス通路２４がアイドルオリフィス通路２６よりも長くなっている。ダンピングオリフィス通路２４は本願発明の横方向防振部２における第１のオリフィス通路であり、アイドルオリフィス通路２６は同じく第２のオリフィス通路である。
【００３８】
左右のすぐり部２７Ｒ、２７Ｌは図３及び図５に示すように、これらの図の上方へ向かって大気開放された凹部状の空間であり、それぞれの底部をドーム部６の薄肉部３４とし、かつ隣り合うすぐり部２７Ｒ又は２７Ｌとの間を弾性仕切壁３５で囲まれている。また、右側のすぐり部２７Ｒは図４に示すように、外側を弾性本体部５と一体の外側面壁３６で囲まれている。但し、外側面壁３６は横副液室２５が設けられる左側のすぐり部２７Ｌには形成されず、その代わりに別体に形成されて取付けられたダイアフラム２８で覆われている。
【００３９】
薄肉部３４は左右のすぐり部２７Ｒ、２７Ｌの底部をなすとともにドーム部６の一部を特別薄肉部化したものであり、中周波領域の振動入力によって膜共振を発生する。弾性仕切壁３５は横主液室２０とすぐり部２７との間を仕切り、左右に斜め前方及び斜め後方へ向かってそれぞれ放射方向へ形成される。
【００４０】
図１に明らかなように、ドーム部６の先端には断面コ字状をなすリング３７が埋設一体化されている。このリング３７は下面のみが露出して仕切り部材８を構成する円筒部１２の外周に形成されている段部３８上へ当接して位置決めしている。第２の取付部材４の内面及び液室カバー２２の下端部にはドーム部６の先端が密着してシールする。また、端部壁２１の外周部にもリング３９が埋設一体化され、第２の取付部材４の上端を内側へ折り曲げたカシメ部４０で固定されている。
【００４１】
第２の取付部材４のうち仕切り部材８の近傍部側となる下方部分は小径部４１をなし、この小径部４１とその上方部分の境界部に形成された段部４２へドーム部６の先端でリング３７の上部側外周部近傍部分を乗せている。上下のリング３７，３９間に液室カバー２２を挟んで上部のカシメ部４０により固定している。小径部４１の内側には、予め固定リング４３が溶接されており、この固定リング４３の上へ、ダイアフラム９の外周に形成された肥大部、押さえプレート１３、円筒部１２及びリング３７を順に重ねることにより、仕切り部材８とダイアフラム９が一緒に固定されている。
【００４２】
横方向防振部２を構成する弾性本体部５、前側端部壁２１Ａ、後側端部２１Ｂ及び弾性仕切壁３５は全て同じ単一の弾性部材で連続一体に構成される。但し、前側端部壁２１Ａ、後側端部２１Ｂ、弾性仕切壁３５及び弾性本体部５のうち少なくともいずれかを部分的に特性の異なる弾性材料で構成して全体として単一の弾性部材に一体化することは任意にできる。また、これらの弾性材料を縦方向防振部１と共通にするから、ダイアフラム９を除く縦方向防振部１の弾性材料部分と横方向防振部２の弾性材料部分が一体に形成される単一の内挿体７（図５）となり、このエンジンマウント組立時に単品として扱うことができる。
【００４３】
図１及び図４に示すように、横方向防振部２において、前側横主液室２０Ａ内に横膜５０が設けられている。横膜５０は弾性本体部５と別体に構成され、後述する吸気負圧により弾性変形されるため、構成材料もヒドリンゴムなどの耐ガソリン性及び耐熱性に優れたものとなっており、周囲に一体化されたリング状のインサート５１に囲まれた内側部分が弾性変形自在になっている。
【００４４】
横膜５０は前側横主液室２０Ａの側方開放部へ嵌合されて前側横主液室２０Ａを覆うようになっている。横膜５０を弾性本体部５と別体に形成することによって、高価な耐ガソリン性ゴムを最小部分に限定でき、トータルコストを低減できる。また必要な部分のみへ最適物性の材料を限定使用でき、かつ取付も開放部へ嵌合するだけのため容易になる。
【００４５】
第２の取付部材４のうち前側横主液室２０Ａの部分に横穴５２が形成され、ここに横膜ストッパ５３が嵌合されている。横膜ストッパ５３は耐ガソリン性及び耐熱性に優れたポリプロピレンのような適宜樹脂製であって、パイプ部５４が一体に形成され、その軸部を通る通気路５５が貫通し、横膜ストッパ５３と横膜５０の間に形成される作動室５６と連通している。通気路５５の他端はパイプ部５４を介して切り換えバルブ５７に接続し、切り換えバルブ５７を大気又は負圧源のいずれかへ接続切り換えすることにより、作動室５６を大気開放又は負圧に切り換えるようになっている。
【００４６】
作動室５６に臨む横膜ストッパ５３の表面には、中央側で通気路５５が開口するシート面５８が設けられ、その周囲をリング状に囲んで突起部５９が一体に形成され、さらにその外周側は横膜５０と密着するシール部になっている。
【００４７】
横膜５０が例えば、振幅が０．０３〜０．３ｍｍ程度の微少入力振動で弾性変形するときにはシート面５８及び突起部５９のいずれとも非接触で自由に弾性変形でき、例えば、振幅０．５〜数ｍｍ程度のサスペンションを介して路面から入力するような大きな振動になると、突起部５９だけがシート面５８より先に接触して、横膜５０が突起部５９を支点とする弾性変形を行い、さらに大振動になるとシート面５８へ横膜５０が接触するように設定し、横膜５０のバネを多段階かつ非線形に変化させる設定になっている。なお、作動室５６を負圧にしたときは横膜５０がシート面５８へ吸引密着され、弾性変形不能な拘束状態になる。
【００４８】
図１に示すように、横膜ストッパ５３には取付部材６０の上端部側がインサートされて一体化しており、取付部材６０の下端部側は外向きフランジ６１をなして取付金具６２のフランジ部６３と重ねられ、リベット６４で結合一体化されている。取付金具６２は第２の取付部材４の下部外周へ溶接されている。横膜ストッパ５３はこのリベット６４のみにより第２の取付部材４へ固定される。
【００４９】
次に、本実施例の作用を説明する。横方向防振部２において、上記のように前後の横主液室２０Ａ，２０Ｂを左側のすぐり部２７Ｌに設けた横副液室２５と、ダンピングオリフィス通路２４及びアイドルオリフィス通路２６によって連通させれば、前後方向（Ｘ軸方向）における一般走行時の振動に対してダンピングオリフィス通路２４の液柱共振による高減衰を実現でき、これよりも高周波数側のアイドル振動に対してアイドルオリフィス通路２６の液柱共振により低動バネを実現できる。
【００５０】
しかも横方向防振部２と縦方向防振部１の間には、すぐり部２７の底部をなす薄肉部３４が形成されているので、この薄肉部３４が膜共振することにより、縦方向防振部１における上下方向（Ｚ軸方向）の振動に対して低動バネ化を実現できる。そのうえ、ダンピングオリフィス通路１５により一般走行時における上下方向の振動に対して高減衰となり、かつ弾性膜８ａの存在によって上下方向の振動全体を広範囲の周波数域で低動バネ化できる。
【００５１】
したがって、前後方向及び上下方向の各振動について、一般走行時の低周波大振幅振動に対する高減衰と、これより高周波数側の振動に対する低動バネ化を同時に実現できる。しかも、一対のすぐり部２７のうち、その一方内に横副液室２５を設ければ、すぐり部２７の空間を有効に活用でき、装置の小型化が可能になる。
【００５２】
なお、Ｙ軸方向の振動に対しては、一種のゴムバネをなす弾性仕切壁３５の弾性変形により吸収する。その結果、Ｘ軸方向はダンピングオリフィス通路２４とアイドルオリフィス通路２６の液柱共振により、Ｙ軸方向は弾性仕切壁３５により、Ｚ軸方向は縦方向防振部１によりそれぞれ吸収でき、ＸＹＺ、３軸方向の各振動を効果的に防振できる。
【００５３】
また、弾性仕切壁３５の肉厚等を変更してバネ定数を調整すれば、Ｙ軸方向の振動吸収性能を自由に調整できる。本実施例ではすぐり部２７の形成により、弾性仕切壁３５は柔らかめに設定され、かつ一方のすぐり部２７内に横副液室２５を設けたことにより左右非対称のバネ定数になる。
【００５４】
次に内圧制御について説明する。図６は横膜５０の動作を説明する図であり、そのＡに示すように、作動室５６を大気開放すると、横膜５０は弾性変形自由のフリー状態となる。このため、横膜５０のバネが低くなり、トータルバネも低くなる。したがって、前後又は上下方向の振動が入力することにより、横主液室２０の内圧が変動すると、この内圧変動を横膜５０の弾性変形により吸収して低バネとなる。
【００５５】
このとき、小振幅振動であれば、横膜５０の弾性変形は全くフリーであるから最も低バネの状態となり、多少振動が大きくなって突起部５９と接触すると横膜５０は突起部５９に囲まれた小さな範囲で弾性変形するため、横膜５０のバネが上がる。さらに大振動になると、横膜５０がシート面５８に接触して弾性変形を規制されるのでさらにバネが上がる。したがって、入力振動の大きさによって多段階にバネ定数が変化する非線形のバネ特性を発揮する。
【００５６】
特に、７〜１５Ｈｚ程度の通常走行時における低周波数かつ大振幅振動に対して、横膜５０がシート面５８へ接続して変形規制されたときは、横膜５０が剛体化（本願ではフリー状態より硬くなる状態をいう、以下同）して前側横主液室２０Ａの壁剛性が上がるため、ダンピングオリフィス通路２４へ流れる液量を増大させ、その結果ダンピングオリフィス通路２４の共振効率を上げてより高減衰にすることができる。そのうえ大振動入力に対して横膜５０の弾性変形を規制するから耐久性を向上できる。
【００５７】
図７は横方向防振部２における前後方向振動に対する減衰性能について示すため、横軸に周波数、縦軸に減衰係数Ｃをとったグラフである。このグラフに明らかなように、横膜５０を欠く比較例（破線）に比べて、本実施例（実線）の方が高い減衰係数Ｃを示す。上記低周波数域において本実施例の方が高減衰を実現して乗り心地を向上できる。
【００５８】
なお、このグラフは横方向防振部２における特性である。縦方向防振部１においても、横膜５０の剛体化により、上下振動に対してダンピングオリフィス通路１５の共振効率が向上する。したがって、縦方向防振部１による上下方向振動及び横方向防振部２による前後振動のいずれかにおいても高減衰を得ることができる。
【００５９】
次に、図６のＢに示すように、アイドル周波数（例えば１５〜４０Ｈｚ程度）になると、切り換えバルブ５７により作動室５６を負圧にして、横膜５０をシート面５８へ吸引密着させる。これにより、横膜５０は剛体化するので、トータルバネが高くなり、アイドルオリフィス通路２６の共振効率が向上し、低動バネ化する。
【００６０】
図８はこれを示し、動バネ定数Ｋを比較例（破線）に比べて本実施例（実線）の方がアイドル周波数にて低動バネ化できる。なお、このグラフも横方向防振部２における前後方向振動に対する特性であり、横軸に周波数、縦軸に動バネ定数（絶対バネＫ）をとったものである（以下の図９、１０も同様）。
【００６１】
さらに加速時の振動による中高周波数（５０〜１ＫＨｚ）の振動に対しては、図６のＣに示すように、作動室５６を大気開放する。しかもこの振動は比較的小さな振幅であるため、横膜５０は横膜ストッパ５３による変形規制を受けずフリーとなり、横膜５０のバネが最も低くなるから、トータルバネも低バネ化する。
【００６２】
図９は中高周波数における横膜５０の及ぼす効果を示すため装置全体における上下振動に対する動バネ特性を示し、本実施例（実線）の動バネ定数Ｋは比較例（破線）よりも全体的に低くなり、図示の中高周波数域全体で低動バネを実現できる。
【００６３】
図１０は、膜共振の影響を説明するため、縦軸に動バネ定数（絶対バネ定数）Ｋ、横軸に周波数をとったグラフであり、図９と同様の中高周波数（５０〜１ＫＨｚ）域における上下振動に対する動バネ特性を示す。なお、このグラフ中には上部として横方向防振部２における各液室にのみ液体を封入し、縦方向防振部１の各液室には液体を封入しない状態で測定した、主として端壁部２１Ａ及び２１Ｂの膜共振の効果を示すものと、下部として縦方向防振部１における各液室にのみ液体を封入し、横方向防振部２の各液室には液体を封入しない状態で測定した、主としてドーム部６の膜共振の効果を示すものと、縦方向防振部１及び横方向防振部２の各液室に液体を封入した状態で測定したトータルバネを示すものを併記してある。
【００６４】
この例では、上部における前側の端壁部２１Ａと後側の端壁部２１Ｂのバネを代えてある。具体的には前側の端壁部２１Ａよりも後側の端壁部２１Ｂを肉厚にし、膜共振周波数を、前側の端壁部２１Ａ＜後側の端壁部２１Ｂ＜ドーム部のうち例えば左側の薄肉部３４＜ドーム部の例えば右側の薄肉部３４、
となるように設定する。これにより上部である横方向防振部２は、前側の端壁部２１Ａによる膜共振に基づくピークＰ１とこれよりも高周波側において後側の端壁部２１Ｂによる膜共振に基づくピークＰ２を形成する。さらに下部である縦方向防振部１では左側の薄肉部３４の膜共振によるピークＰ３がＰ２よりも高周波側に生じ、さらにこれよりも高周波側に右側の薄肉部３４の膜共振によるピークＰ４が生じる。
【００６５】
この例によれば、上部の動バネ特性における端壁部２１Ａ及び２１Ｂによる膜共振のピークＰ１，Ｐ２の発生後、下部の動バネ特性における左右のドーム部６の薄肉部３４による膜共振のピークＰ３，Ｐ４が発生するようになっているが、これらを連成した状態となるトータルバネのグラフは、各膜共振のピークＰ１，Ｐ２及びＰ３、Ｐ４の相互作用により、実線で示すように広範囲においてより低動バネを実現できている。
【００６６】
本実施例におけるこのような低動バネ化の現象に対する理論的な解明はなされていないが、縦方向防振部１及び横方向防振部２の双方へ液体を封入した実際の使用状態では、横方向防振部２へ振動が入力することにより、その液圧変化がドーム部６へ及ぼされて縦主液室１０の内圧に影響を与える結果、これによって低動バネ化を実現するものと考えられる。
【００６７】
また、縦方向防振部１への振動入力によってドーム部６より横方向防振部２における各液室の内圧へ影響が与えられる結果、トータルバネの低動バネ化を実現するものと考えられる。いずれにしろ、縦方向防振部１と横方向防振部２の相互作用によって、それぞれの膜共振を利用してトータルバネの低動バネ化を達成させることができる。縦方向防振部１と横方向防振部２におけるそれぞれの膜共振を複数の周波数で発生させるようにしたので、広範囲における低動バネ化を実現するブロード化が可能になっている。
【００６８】
しかも、横膜５０を設けて全体を低バネにしたので、従来と同程度のトータルバネに設定する場合には、前後の端壁部２１Ａ、２１Ｂ及び左右の薄肉部３４、のいずれかもしくは全体をより厚肉にして高バネにできる。その結果、これらの膜共振周波数をより高周波側へ移すことができ、さらに広範囲の周波数域において低動バネを可能にする。
【００６９】
なお、上記実施例の他に種々なバリエーションが可能である。例えば前後の端壁部２１Ａ、２１Ｂ及びドーム部６、特に薄肉部３４の厚さを調整した種々の組合せが可能である。図１１はこの略図であり、便宜上端壁部２１のうち前側を２１Ａ，後ろ側を２１Ｂ、ドーム部６の薄肉部３４のうち右側を３４Ｒ，左側を３４Ｌとする。図１１の上部は前後方向にて端壁部２１Ａ、２１Ｂを示し、下部は左右方向にて左右の薄肉部３４Ｒ，３４Ｌを同時に示す。
【００７０】
このとき、まず、薄肉部の厚さの関係において、３４Ａ＞３４Ｂ，３４Ａ＝３４Ｂ，３４Ａ＜３４Ｂの３通りが可能である。同様に端壁部の厚さの関係も２１Ａ＞２１Ｂ，２１Ａ＝２１Ｂ，２１Ａ＜２１Ｂの３通りが可能である。したがって、薄肉部と端壁部の組合せにおいては計９通りが可能となる。
【００７１】
このように、種々の厚さを変化すると、前後、左右並びに上下の各振動方向に対する方向性を自在に設定できるとともに膜共振周波数を種々に異なった組合せにでき、その結果、これらの連成効果のため防振すべき振動の方向を自由に設定でき、かつより広範囲の低動バネ化を実現できる。
【００７２】
さらに、横膜５０は前側横主液室２０Ａだけではなく、後ろ側もしくは前後それぞれに設けることができる。そのうえ、前後の横主液室２０Ａ、２０Ｂは一例であって、これを左右とすることもできる。また、上記実施例のように、主液室を前後（又は左右）の２室ではなく、より多数にすることもでき、この場合には横膜５０も２以上の複数を設けることができる。また、内圧制御手段として吸気負圧を利用するものだけではなく、ソレノイドやモーターの駆動により横膜５０を強制的に弾性変形させてもよい。このようにすれば応答性に優れた電気的制御が可能になる。
【００７３】
次に、第２実施例を説明する。なお前実施例と共通する部分には共通符号を用い、原則として重複した説明は省略する。図面に基づいて車両のエンジンマウントに構成された一実施例を説明する。図１２は図２と対応する図、図１３は図４と対応する図、図１４は図５と対応する図である。
【００７４】
図１２に明らかなように、横方向防振部２の端部壁２１が全体として略円盤状をなし、前実施例のようなすぐり部２７Ｒ、２７Ｌが形成されていない点で相違する。また図１３に示すように、前側横主液室２０Ａと後側横主液室２０Ｂを構成する４つの弾性仕切壁３５のうち、右側の前後２つの間に横弾性仕切壁７０Ｒが設けられ、左側の前後２つの間に横弾性仕切壁７０Ｌが設けられている。両横弾性仕切壁７０Ｒ、７０Ｌは、第１の取付部材３を挟んで左右方向反対側へ延出し、弾性仕切壁３５と同様に弾性本体部５の一部として一体に形成されている。
【００７５】
両横弾性仕切壁７０Ｒ、７０Ｌの断面積は弾性仕切壁３５と比べて数倍大きなものであって、左右方向を著しく高バネにし、Ｙ軸方向の振動を主として両横弾性仕切壁７０Ｒ、７０Ｌの弾性変形により吸収する。両横弾性仕切壁７０Ｒ、７０Ｌの各先端は液室カバー７１Ｒ、７１Ｌのそれぞれに一体形成されている連結凸部７２Ｒ、７２Ｌと嵌合し、右側における前後２つの弾性仕切壁３５と横弾性仕切壁７０Ｒの間で右側前横液室２０Ｃ及び右側後横液室２０Ｄと、左側における前後２つの弾性仕切壁３５と横弾性仕切壁７０Ｌの間で左側前横液室２０Ｅ及び左側後横液室２０Ｆとを区画する。
【００７６】
右液室カバー７１Ｒ、左液室カバー７１Ｌは樹脂等の適当な材料からなる略半円弧状の部材であって、第２の取付部材４の内周面へ密に嵌合し、横膜５０と共に全体として一つの円弧を形成する。右液室カバー７１Ｒ、左液室カバー７１Ｌには、各弾性仕切壁３５の先端もそれぞれ密接し、その密接部と連結凸部７２Ｒ、７２Ｌとの間に、右側前横液室２０Ｃへの連通口７３Ｒ及び右側後横液室２０Ｄへの連通口７４Ｒ、並びに左側前横液室２０Ｅへの連通口７３Ｌ及び左側後横液室２０Ｆへの連通口７４Ｌが形成されている。
【００７７】
連通口７３Ｒと７４Ｒの間は右アイドルオリフィス通路７５Ｒで連通され、右側前横液室２０Ｃと右側後横液室２０Ｄの間で液体流動を可能とし、かつアイドル周波数に共振点をチューニングさせてある。連通口７３Ｌと７４Ｌの間も左アイドルオリフィス通路７５Ｌで連通され、左側前横液室２０Ｅと左側後横液室２０Ｆの間で液体流動を可能とし、かつアイドル周波数に共振点をチューニングさせてある。
【００７８】
これらの右アイドルオリフィス通路７５Ｒ及び左アイドルオリフィス通路７５Ｌは、それぞれ右液室カバー７１Ｒと左液室カバー７１Ｌの各外周部に形成された溝と第２の取付部材４の内周面との間に形成されている。
【００７９】
一方、これらの右アイドルオリフィス通路７５Ｒ及び左アイドルオリフィス通路７５Ｌの図示状態で下方位置には、右ダンピングオリフィス通路７６Ｒ及び左ダンピングオリフィス通路７６Ｌが重なって設けられる。右ダンピングオリフィス通路７６Ｒは、横膜５０の右側端部近傍における右液室カバー７１Ｒの前端部と前側の弾性仕切壁３５との接続部に形成された連通口７７Ｒで前側横主液室２０Ａと連通し、右液室カバー７１Ｒの後端部に設けられた連通口７８Ｒで後側横主液室２０Ｂと連通する。
【００８０】
左ダンピングオリフィス通路７６Ｌは、横膜５０の左側端部近傍における左液室カバー７１Ｌの前端部と前側の弾性仕切壁３５との接続部に形成された連通口７７Ｌで前側横主液室２０Ａと連通し、左液室カバー７１Ｌの後端部に設けられた連通口７８Ｌで後側横主液室２０Ｂと連通する。右液室カバー７１Ｒと左液室カバー７１Ｌの各後端部は、パイプ部５４の延長上となる後側横主液室２０Ｂの中間部で接し、連通口７８Ｒと連通口７８Ｌは一体化している。
【００８１】
なお、右ダンピングオリフィス通路７６Ｒ及び左ダンピングオリフィス通路７６Ｌは、右アイドルオリフィス通路７５Ｒ及び左アイドルオリフィス通路７５Ｌに比べて、いずれも通路断面積が小さくかつ長いことにより、右アイドルオリフィス通路７５Ｒ及び左アイドルオリフィス通路７５Ｌの各共振点より低い一般走行時における低周波数域の入力振動に共振点が合うようになっている。
【００８２】
図１４に示すように、左横弾性仕切壁７０Ｌの先端は凹部７９をなし、この凹部７９に連結凸部７２Ｌが嵌合し、図の上下方向へ一体に形成されたシール８０によって液密に接合し、かつ左横弾性仕切壁７０Ｌの先端が連結凸部７２Ｌ上を摺動可能になっている。なお右横弾性仕切壁７０Ｒと連結凸部７２Ｒの関係も同様である。また、各弾性仕切壁３５の先端面にもシール８１が上下方向に形成され、右液室カバー７１右又は左液室カバー７１Ｌに対して液密に接合するようになっている。
【００８３】
本実施例では、主として前後方向の振動を防振するものであって、前後方向の振動が発生すると、液体は左右のアイドルオリフィス通路７５Ｌ及び７５Ｒを通って右側前横液室２０Ｃ及び右側後横液室２０Ｄの間、並びに左側前横液室２０Ｅ及び左側後横液室２０Ｆの間を移動し、アイドルオリフィス周波数で液柱共振して低動バネになる。また、左右のダンピングオリフィス通路７６Ｌ及び７６Ｒを通って前側横主液室２０Ａと後側横主液室２０Ｂの間に流動し、やはり所定の低周波数で液柱共振を生じて高減衰となる。
【００８４】
このとき、横膜５０及び内圧制御手段は前実施例と全く同じ構成であり、前実施例同様に機能する。すなわち内圧制御はアイドルオリフィス通路７５Ｌ及び７５Ｒの共振周波数のとき横膜５０を拘束する。すると前側横主液室２０Ａの壁剛性は高くなるため、前側横主液室２０Ａと右側前横液室２０Ｃ及び左側前横液室２０Ｅとの間の弾性仕切壁３５の壁剛性も高くなることになり、その結果、右側前横液室２０Ｃ及び左側前横液室２０Ｅの各壁剛性が高くなって、アイドルオリフィス通路７５Ｌ及び７５Ｒの共振効率を向上させる。
【００８５】
さらに、ダンピングオリフィス通路７６Ｌ及び７６Ｒの共振周波数でも横膜５０を拘束してもよい。なお、端部壁２１が略円盤状であるため、前後の端壁部２１Ａ及び２１Ｂはそれぞれ、前側横主液室２０Ａ及び後側横主液室２０Ｂの上方となる部分とし、ドーム部６の薄肉部３４は、前実施例の左右に代わって前側横主液室２０Ａ及び後側横主液室２０Ｂを構成するドーム部６の前部又は後部とする。
【００８６】
また、本実施例では液室２０Ａと２０Ｂを主液室とし、他の液室２０Ｃ〜２０Ｆと異なる名称にしてあるが、これは液室２０Ａと２０Ｂについて特に前実施例との対応上同じ表現を用いただけであり、各液室２０Ａ〜２０Ｆはいずれも機能上において主副の差がない横液室を構成する。
【図面の簡単な説明】
【図１】実施例に係るエンジンマウントの図２における１−１線断面図
【図２】実施例に係るエンジンマウントの平面図
【図３】図２の１−３線断面図
【図４】図１の４−４線断面図
【図５】内挿体の斜視図
【図６】横膜の動作説明図
【図７】減衰特性を示すグラフ
【図８】アイドル時の動バネ特性を示すグラフ
【図９】中高周波数域の動バネ特性を示すグラフ
【図１０】各部の動バネ特性をあわせて示すグラフ
【図１１】弾性壁の肉厚変化の組合せを示す略図
【図１２】第２実施例に係る図２と対応する図
【図１３】第２実施例に係る図４と対応する図
【図１４】第２実施例に係る図５と対応する図
【符号の説明】
１：縦方向防振部、２：横方向防振部、３：第１の取付部材、４：第２の取付部材，５：弾性本体部、６：ドーム部、７：弾性本体部、８：仕切り部材、８ａ：弾性膜、１０：縦主液室、１１：縦副液室、１５：ダンピングオリフィス通路、２０Ａ：前側主液室、２０Ｂ：後側主液室、２１Ａ：前側端部壁、２１Ｂ：後側端部壁、２２：液室カバー、２４：ダンピングオリフィス通路、２５：横副液室、２６：アイドルオリフィス通路、２７：すぐり部、３４：薄肉部、３５：弾性仕切壁、３６：外側面壁、５０：横膜、５３：横膜ストッパ、５６：作動室[0001]
BACKGROUND OF THE INVENTION
The present invention is a liquid seal vibration isolator used for an engine mount or the like, and a vertical vibration isolator for mainly isolating input vibration in a main vibration input direction (hereinafter referred to as a Z-axis direction and a vertical direction); , Integrated with a horizontal vibration isolator that mainly dampens input vibration in a direction orthogonal to the Z-axis direction (hereinafter referred to as the X / Y-axis direction and the horizontal direction). In particular, the present invention relates to a device for making a spring characteristic and a damping characteristic variable according to an input vibration by controlling an internal pressure of a liquid chamber.
[0002]
[Prior art]
A first attachment member attached to the vibration generating side, a second attachment member attached to the vibration receiving side, and a substantially conical elastic body member connecting the first attachment member and the second attachment member A liquid chamber having the elastic main body portion as a part of the elastic wall portion is provided inside the elastic main body portion, the liquid chamber is divided into two by a partition member, and the two liquid chambers are divided into the first orifice passage. The conical mount in which the main liquid chamber and the sub liquid chamber are arranged in the Z-axis direction is known. Also, a cylindrical bush that connects the cylindrical inner and outer cylinders with an elastic member, and has a plurality of liquid chambers partitioned between the inner and outer cylinders in the circumferential direction by an elastic member, and these liquid chambers are connected by an orifice passage. It is well known.
[0003]
Furthermore, a liquid seal vibration isolator having an engine mount obtained by combining and integrating such a cylindrical bush and a conical mount is known. In this way, the main vibration can be absorbed by the conical mount portion, and the vibration in the direction orthogonal to the conical mount portion can be absorbed by the cylindrical bush portion. Can absorb all vibrations. Examples of such a structure include JP-B-63-61533, JP-A-61-262244, JP-A-2002-21914, JP-A-2001-349369, JP-A-2002-39355, JP-A-2002-89613, JP-A-2002-98155. JP 2002-122175A.
In addition, there are various types in which a part of the elastic wall facing the liquid chamber in the longitudinal vibration portion is an elastic film that can be elastically deformed and provided with an internal pressure control means for controlling the internal pressure in the liquid chamber by controlling this elastic deformation. It is known. Examples of such a structure include JP-A-10-38017, JP-A-10-281214, and JP-A-2002-070931.
Furthermore, it is also known that a part of the elastic wall facing the liquid chamber in the longitudinal vibration portion is thinned to make a low dynamic spring by utilizing the membrane resonance and broaden the range. As an example of such a structure, there is JP-A-11-351311.
[0004]
[Problems to be solved by the invention]
By the way, even if the vertical vibration isolator and the horizontal vibration isolator as described above are integrated, the internal pressure generated corresponding to the input vibration in each portion is determined by the shape of the elastic member, etc. Therefore, the spring characteristic and the damping characteristic are also determined according to the input vibration. However, if the internal pressure of the liquid chamber can be controlled, the spring pressure and damping characteristics change optimally according to the input vibration by increasing the internal pressure when you want to increase the resonance efficiency and conversely reducing the internal pressure when you need a low dynamic spring. It becomes possible to make it.
[0005]
Such internal pressure control is well known in the vertical vibration isolator as exemplified above, but in the liquid seal vibration isolator in which the vertical vibration isolator and the horizontal vibration isolator are combined and integrated, If such internal pressure control is to be performed in any of the lateral directions, internal pressure control means must be provided in each of the vertical vibration isolation unit and the horizontal vibration isolation unit, which increases the complexity and size of the device and greatly increases the cost. Will invite up.
[0006]
Therefore, in a vibration isolator that combines a vertical vibration isolator and a horizontal vibration isolator, the internal pressure can be controlled for both vertical and horizontal vibrations, and the device can be simplified, downsized, and cost reduced. It would be desirable to make it possible. The object of the present invention is to realize such a demand.
[0007]
[Means for Solving the Problems]
In order to solve the above-described problem, a liquid seal vibration isolator according to claim 1 includes a longitudinal vibration isolator that mainly isolates main vibrations, and a lateral direction that mainly isolates vibrations in a direction orthogonal to the input direction of the main vibrations. A liquid seal vibration isolator integrated with a vibration isolator, wherein the longitudinal vibration isolator is in the main vibration input direction, an elastic member, and a vertical main liquid chamber having the elastic member as a part of a wall; A vertical auxiliary liquid chamber communicating with the vertical main liquid chamber via an orifice passage is provided, and the horizontal vibration isolator is provided with a plurality of horizontal liquid chambers in a plane perpendicular to the input direction of the main vibration. In the case where the transverse liquid chambers communicate with each other through an orifice passage, the elastic wall constituting the vertical main liquid chamber of the vertical vibration isolating portion forms part of the elastic wall constituting each liquid chamber of the horizontal vibration isolating portion. And at least one of the lateral liquid chambers constituting the lateral vibration isolator for controlling the internal pressure It is characterized in that a pressure control meansThe
[0008]
Also,The internal pressure control means includes a movable film that is elastically deformed by fluctuations in the internal pressure of the lateral liquid chamber, and a movable film stopper that regulates deformation of the movable film, and is free or movable when the movable film is freely elastically deformed. It switches to the restraint state fixed on a film | membrane stopper, It is characterized by the above-mentioned.
[0009]
Claim2Is the above claim1The movable film stopper provides the movable film with a non-linear spring characteristic by changing the spring constant by bringing the movable film into contact with the movable film when the movable film is not restrained.
[0010]
Claim3Is the above claim1The internal pressure control means controls the operation chamber by switching the working chamber formed between the movable film and the movable film stopper to the atmospheric pressure or the intake negative pressure.
[0011]
Claim4Is the above claim1The internal pressure control means controls the movable film by driving it with a solenoid or a motor.
[0012]
Claim5Is the above claim1-4In any one of the above, the movable film is formed separately from other elastic members constituting the transverse liquid chamber.
[0014]
Claim6In the first aspect of the present invention, the orifice passage in the lateral vibration isolating portion includes at least first and second orifice passages having different resonance frequencies.
[0015]
Claim7In claim 1, the thickness of the elastic wall constituting at least a part of the elastic walls constituting the liquid chambers of the longitudinal vibration isolating portion and the lateral vibration isolating portion is set to be different from that of the other liquid chambers. The thickness is different from the thickness of the elastic wall.
[0016]
【The invention's effect】
According to the first aspect, since the internal pressure control means is provided in at least one of the plurality of horizontal liquid chambers constituting the lateral vibration isolator, the internal pressure control is performed for vibrations requiring a low dynamic spring. By lowering the internal pressure of the lateral liquid chamber by means, the whole spring is reduced. For vibrations that require high damping, the internal pressure control means increases the internal pressure of the lateral liquid chamber to increase the resonance efficiency and realize high damping.
[0017]
In addition, a part of the elastic wall constituting the horizontal liquid chamber of the horizontal vibration isolating part becomes an elastic wall constituting the vertical main liquid chamber of the vertical vibration isolating part so that the vertical vibration isolating part and the horizontal anti-vibration part Since the vibrator is combined and integrated, the horizontal liquid chamber and the vertical main liquid chamber are linked to each other via a common elastic wall, and the result of internal pressure control performed on the horizontal liquid chamber is the result of the vertical main liquid chamber. It reaches. Therefore, it is sufficient to provide the internal pressure control means in at least one of the horizontal liquid chambers, and the installation on the vertical vibration isolator side can be omitted. In spite of the seal vibration isolator, the internal pressure can be controlled with respect to both vertical and horizontal vibrations, and the apparatus can be easily and miniaturized and the cost can be reduced.
[0018]
Also,Since the internal pressure control means includes the movable film and the movable film stopper, the vibration is reduced to a low dynamic spring by absorbing the internal pressure by placing the movable film in a free state against vibration that requires a low dynamic spring. For vibrations that require high damping, the movable film is fixed on the movable film stopper to be in a restrained state, thereby increasing the wall rigidity of the horizontal liquid chamber and increasing the orifice between the horizontal liquid chambers. High attenuation is achieved by increasing the amount of liquid flowing into the passage.
[0019]
Claim2According to the above, when the input vibration increases, the movable film abuts on the movable film stopper, so that free elastic deformation is restricted and the movable film spring increases, so the spring constant before and after the movable film abuts on the movable film stopper. Can be changed nonlinearly, and appropriate spring characteristics can be realized according to the magnitude of the input vibration.
[0020]
Claim3Therefore, the movable film is controlled by switching between opening to the atmosphere and suction by suction negative pressure, so that the opening of the working chamber formed between the moving film and the movable film stopper is made free. When the suction is performed by the negative suction pressure, the movable film is attracted and fixed to the movable film stopper to be in a restrained state. Therefore, the internal pressure control means can be easily realized by utilizing the intake negative pressure of the engine.
[0021]
Claim4Accordingly, since the movable film is controlled by driving with a solenoid or a motor, the internal pressure control means can be easily realized by the electric drive control.
[0022]
Claim5According to the above, since the movable membrane is configured as another elastic member constituting the transverse liquid chamber, only the movable membrane can be made of a different physical property material from other elastic members, and the material having the optimum physical properties is limited to only necessary portions. Since other elastic walls can be used as they are, the entire cost can be suppressed and optimum performance can be obtained.
[0024]
Claim6According to the above, since at least the first and second orifice passages are provided as the orifice passages in the lateral vibration isolator and the respective resonance frequencies are made different, liquid column resonance is generated at a plurality of frequencies, and The resonance efficiency can be improved.
[0025]
Claim7According to the above, the thickness of the elastic wall constituting the liquid chamber of at least a part of the elastic wall constituting each liquid chamber of the vertical direction vibration isolating portion and the horizontal direction vibration isolating portion is set to the thickness of the elastic wall constituting the other liquid chamber. By making the thicknesses different, it is possible to generate membrane resonances at a plurality of different frequencies, and as a result, these plurality of membrane resonances can be coupled to reduce the frequency range over a wider frequency range.
[0026]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an embodiment configured as an engine mount of a vehicle will be described with reference to the drawings. FIG. 1 is an overall cross-sectional view of the engine mount (cross-sectional view taken along line 1-1 of FIG. 2), FIG. 2 is a plan view showing the upper side when the vehicle body is mounted in the Z-axis direction, and FIG. FIG. 4 is a sectional view taken along line 4-4 of FIG. 1, FIG. 5 is a perspective view of an insertion body in which the first mounting portion and the elastic member are integrated, and FIG. 6 is an explanatory diagram of internal pressure control, FIGS. 7 to 10 are graphs showing spring characteristics, and FIG. 11 is a schematic diagram showing a combination of wall thickness changes of the elastic wall.
[0027]
In the following description, the left-right direction, the up-down direction, and the up-down direction in FIG. 1 in the illustrated state of FIG. 2 are the X-axis direction, the Y-axis direction, and the Z-axis direction, respectively. These X-axis direction, Y-axis direction, and Z-axis direction correspond to the front-rear direction and the left-right direction when the vehicle body is mounted, and the vertical direction, respectively.
[0028]
In these drawings, this engine mount is formed by integrally forming a longitudinal vibration isolating portion 1 that is a portion corresponding to a conical mount and a lateral vibration isolating portion 2 that is a portion corresponding to a cylindrical bush. The vertical vibration isolator 1 includes a first attachment member 3 attached to the engine side, a second attachment member 4 configured as a rigid cylindrical outer frame surrounding the periphery of the first attachment member 3 with a space therebetween, and the first attachment member 3. It has an elastic main body portion 5 that connects between the attachment member 3 and the second attachment member 4.
[0029]
The first mounting member 3 has an axial center direction that coincides with the Z-axis direction, which is the main vibration input direction in the longitudinal vibration isolator 1, and the portion embedded in the elastic body 5 has a small diameter at the bottom. It is formed into a cylindrical shape that extends downward along the Z-axis direction. A portion of the first mounting member 3 that protrudes upward from the elastic main body portion 5 forms a flat portion and is mounted on an engine bracket (not shown).
[0030]
A substantially conical space formed by a substantially conical dome portion 6 which is a part of the elastic main body portion 5 forms a liquid chamber and is opened downward in FIG. 1, and the partition member 8 and the diaphragm 9 are provided in the open portion. A portion formed between the inner wall of the dome portion 6 and the partition member 8 is a vertical main liquid chamber 10, and a portion between the partition member 8 and the diaphragm 9 is a vertical auxiliary liquid chamber 11. A vertical main liquid chamber 10 and a vertical auxiliary liquid chamber 11 are partitioned. The diaphragm 9 is a flexible membrane member having a weak spring that is almost negligible for the dynamic characteristics of the engine mount. The dome portion 6 forms part of an elastic wall constituting the horizontal liquid chamber 20, and the vertical main liquid chamber 10 and the vertical auxiliary liquid chamber 11 are arranged side by side in the Z-axis direction. Sex liquid is enclosed.
[0031]
The partition member 8 is configured by a cylindrical portion 12 made of resin or the like and a pressing plate 13 having a smaller diameter and fitting to the inside from the side of the vertical sub-liquid chamber 11. An orifice passage 15 is formed and functions as a damping orifice that constantly communicates the vertical main liquid chamber 10 and the vertical auxiliary liquid chamber 11 and generates liquid column resonance at a predetermined low frequency to realize high attenuation. The partition member 8 has an elastic film 8 a that absorbs the internal pressure of the vertical main liquid chamber 10. The elastic film 8 a has a substantially circular shape in plan view, and is fixed between the cylindrical portion 12 and the pressing plate 13.
[0032]
The central portions of the cylindrical portion 12 and the pressing plate 13 form circular step portions 12b and 13b that protrude toward the vertical main liquid chamber 10, and the step portions 12b and 13b are parallel to each other at a predetermined interval above and below the elastic film 8a. The through-holes 12a and 13a are provided in each, and the elastic membrane 8a is elastically deformable according to the hydraulic pressure of the vertical main liquid chamber 10. However, the stepped portions 12b and 13b of the cylindrical portion 12 and the pressing plate 13 are in contact with the central portion 8b of the elastic film 8a and support the upper and lower sides of the elastic film 8a. As a result, the elastic film 8a is elastically deformed with a relatively short span between the central portion 8b and the fixed portions of the outer peripheral portion, and absorbs the internal pressure of the vertical main liquid chamber 10.
[0033]
The dome portion 6 is an elastic wall that covers the vertical main liquid chamber 10, and the lateral vibration isolating portion 2 is formed on a plurality of horizontal main liquid chambers (the main wall on the dome portion 6, the outer wall of which is a part of the elastic wall). In the embodiment, a pair of front and rear 20A and 20B) is formed. These front and rear horizontal main liquid chambers 20A and 20B are opened laterally to form a substantially triangular space in the cross section shown in FIG. 1, and are formed integrally with the elastic main body 5 and spread in a substantially horizontal front-rear direction. The front and rear end walls 21 A and 21 B are sealed with the dome 6 and the liquid chamber cover 22 or the lateral membrane 50.
In this embodiment, a liquid chamber cover 22 is attached to a lateral main liquid chamber (hereinafter referred to as a rear lateral main liquid chamber) 20B which is the rear side when the vehicle body is mounted, and the horizontal main liquid chamber which is the front side when the vehicle body is mounted. A transverse membrane 50 is attached to 20A (hereinafter referred to as a front side main liquid chamber).
[0034]
As shown in FIG. 4, the liquid chamber cover 22 has an arc shape with a substantially ¼ circumference on the inner peripheral surface of the second mounting member 4, and is fitted to the rear side main liquid chamber 20 B and has an opening edge thereof. Closely to. Grooves 23 extending in the circumferential direction are provided on the outer surface of the liquid chamber cover 22 that comes into contact with the second mounting member 4 in two upper and lower stages and are opened to the second mounting member 4 side. A damping orifice passage 24 and an idle orifice passage 26 are formed between the mounting member 4 and the mounting member 4. The idle orifice passage 26 communicates the rear side main liquid chamber 20 B and the side sub liquid chamber 25.
[0035]
The lateral auxiliary liquid chamber 25 has a diaphragm 28 in the interior thereof with respect to the left side straight part 27L which is one of the right and left side straight parts 27R and 27L provided between the front and rear horizontal main liquid chambers 20A and 20B. In the case of the present embodiment, it is formed between the diaphragm 28 and the second mounting member 4. The diaphragm 28 is a flexible membrane member similar to the diaphragm 9 in the vertical vibration isolator 1. Reference numeral 29 in the drawing is a substantially quadrilateral frame bracket embedded in the seat portion of the diaphragm 28, which serves to position the diaphragm 28 when it is attached and to seal the lateral auxiliary liquid chamber 25 in a liquid-tight manner.
[0036]
The damping orifice passage 24 in the lateral vibration isolating section 2 communicates with the front lateral main liquid chamber 20A and the entrance 30 and a groove 31 (FIG. 4) formed on the outer surface of the elastic partition wall 36 constituting the right side straight section 27R and It communicates with the lateral auxiliary liquid chamber 25 through the lower groove 23 formed on the outer surface of the liquid chamber cover 22 and at the outlet (overlapping the outlet 33 of the idle orifice passage 26 in FIG. 4). Similarly, the idle orifice passage 26 communicates with the rear side main liquid chamber 20 B through the inlet 32, and communicates with the side auxiliary liquid chamber 25 and the outlet 33. The outlet 33 and the idle orifice passage 26 communicate with each other via a groove 35a formed on the outer surface of the elastic partition wall 35 (FIG. 4).
[0037]
However, the damping orifice passage 24 and the idle orifice passage 26 have different passage characteristics such as length and passage cross-sectional area. As a result, the damping orifice passage 24 has a low frequency vibration (for example, 7 to The idle orifice passage 26 has a resonance point for idle vibration on a higher frequency side (for example, about 15 to 40 Hz). In this embodiment, the damping orifice passage 24 is longer than the idle orifice passage 26. The damping orifice passage 24 is a first orifice passage in the lateral vibration isolator 2 of the present invention, and the idle orifice passage 26 is also a second orifice passage.
[0038]
As shown in FIGS. 3 and 5, the right and left straight portions 27 R and 27 L are recessed spaces that are open to the atmosphere upward in these drawings, and the bottom portions thereof are the thin portions 34 of the dome portion 6. In addition, an elastic partition wall 35 surrounds the adjacent straight portion 27R or 27L. Further, as shown in FIG. 4, the right side straight portion 27 R is surrounded by an outer surface wall 36 that is integral with the elastic main body portion 5. However, the outer side wall 36 is not formed in the left side straight portion 27L where the transverse auxiliary liquid chamber 25 is provided, but instead is covered with a diaphragm 28 which is formed separately and attached.
[0039]
The thin portion 34 forms the bottom of the right and left straight portions 27R and 27L, and a part of the dome portion 6 is specially thinned. The membrane resonance is generated by vibration input in the middle frequency region. The elastic partition wall 35 partitions the horizontal main liquid chamber 20 and the straight portion 27, and is formed in a radial direction diagonally forward and diagonally rearward to the left and right.
[0040]
As apparent from FIG. 1, a ring 37 having a U-shaped cross section is embedded and integrated at the tip of the dome portion 6. Only the lower surface of the ring 37 is exposed and positioned on the stepped portion 38 formed on the outer periphery of the cylindrical portion 12 constituting the partition member 8. The tip of the dome 6 is in close contact with the inner surface of the second mounting member 4 and the lower end of the liquid chamber cover 22 for sealing. A ring 39 is also embedded and integrated in the outer peripheral portion of the end wall 21, and is fixed by a caulking portion 40 in which the upper end of the second mounting member 4 is bent inward.
[0041]
The lower part of the second mounting member 4 on the side near the partition member 8 forms a small-diameter part 41, and the tip of the dome part 6 extends to a stepped part 42 formed at the boundary between the small-diameter part 41 and the upper part. Thus, the vicinity of the outer periphery of the upper side of the ring 37 is placed. The liquid chamber cover 22 is sandwiched between the upper and lower rings 37 and 39 and fixed by an upper caulking portion 40. A fixing ring 43 is welded in advance to the inside of the small diameter portion 41, and an enlarged portion formed on the outer periphery of the diaphragm 9, the pressing plate 13, the cylindrical portion 12, and the ring 37 are sequentially stacked on the fixing ring 43. Thus, the partition member 8 and the diaphragm 9 are fixed together.
[0042]
The elastic main body 5, the front end wall 21 A, the rear end 21 B, and the elastic partition wall 35 constituting the lateral vibration isolator 2 are all continuously and integrally formed of the same single elastic member. However, at least one of the front end wall 21A, the rear end wall 21B, the elastic partition wall 35, and the elastic main body 5 is partially made of an elastic material having different characteristics, and is integrated into a single elastic member as a whole. It can be arbitrarily made. Further, since these elastic materials are shared with the longitudinal vibration isolator 1, the elastic material portion of the vertical vibration isolator 1 excluding the diaphragm 9 and the elastic material portion of the lateral vibration isolator 2 are integrally formed. It becomes a single insert 7 (FIG. 5) and can be handled as a single item when the engine mount is assembled.
[0043]
As shown in FIGS. 1 and 4, in the lateral vibration isolator 2, a lateral membrane 50 is provided in the front lateral main liquid chamber 20 A. The transverse membrane 50 is configured separately from the elastic main body 5 and is elastically deformed by the intake negative pressure described later, so that the constituent material is also excellent in gasoline resistance and heat resistance such as hydrin rubber, An inner portion surrounded by the integrated ring-shaped insert 51 is elastically deformable.
[0044]
The horizontal membrane 50 is fitted to a side opening portion of the front horizontal main liquid chamber 20A so as to cover the front horizontal main liquid chamber 20A. By forming the transverse membrane 50 separately from the elastic main body 5, the expensive gasoline-resistant rubber can be limited to the minimum portion, and the total cost can be reduced. In addition, the material having the optimum physical properties can be limitedly used only in the necessary part, and the mounting is facilitated because it is only fitted into the open part.
[0045]
A lateral hole 52 is formed in the front lateral main liquid chamber 20 A portion of the second mounting member 4, and a lateral membrane stopper 53 is fitted therein. The lateral membrane stopper 53 is made of an appropriate resin such as polypropylene having excellent gasoline resistance and heat resistance, and the pipe portion 54 is integrally formed, and the air passage 55 passing through the shaft portion passes therethrough. And a working chamber 56 formed between the lateral membrane 50 and the lateral membrane 50. The other end of the air passage 55 is connected to the switching valve 57 via the pipe portion 54, and the switching chamber 57 is switched to either the atmosphere or the negative pressure source to switch the working chamber 56 to the atmosphere open or negative pressure. It is like that.
[0046]
The surface of the lateral membrane stopper 53 facing the working chamber 56 is provided with a seat surface 58 in which the air passage 55 opens on the center side, and a protrusion 59 is integrally formed surrounding the periphery in a ring shape. The side is a seal portion that is in close contact with the lateral membrane 50.
[0047]
For example, when the transverse membrane 50 is elastically deformed by minute input vibration having an amplitude of about 0.03 to 0.3 mm, the sheet surface 58 and the protrusion 59 can be freely elastically deformed without contact, for example, an amplitude of 0.5 When a large vibration is input from the road surface through a suspension of about several millimeters, only the projection 59 comes into contact with the seat surface 58 earlier, and the lateral membrane 50 performs elastic deformation with the projection 59 as a fulcrum. Further, when the vibration becomes larger, the setting is made so that the lateral membrane 50 comes into contact with the seat surface 58, and the spring of the lateral membrane 50 is changed in a multi-stage and non-linear manner. When the working chamber 56 is set to a negative pressure, the lateral membrane 50 is attracted and brought into contact with the seat surface 58, and is in a restrained state that cannot be elastically deformed.
[0048]
As shown in FIG. 1, the upper end side of the mounting member 60 is inserted into and integrated with the transverse membrane stopper 53, and the lower end side of the mounting member 60 forms an outward flange 61 and the flange portion 63 of the mounting bracket 62. And are combined and integrated with a rivet 64. The mounting bracket 62 is welded to the lower outer periphery of the second mounting member 4. The transverse membrane stopper 53 is fixed to the second mounting member 4 only by the rivets 64.
[0049]
Next, the operation of this embodiment will be described. In the lateral vibration isolator 2, the front and rear horizontal main liquid chambers 20A and 20B are communicated with each other by the transverse auxiliary liquid chamber 25 provided in the left side straight portion 27L, the damping orifice passage 24, and the idle orifice passage 26. For example, it is possible to realize high damping due to liquid column resonance of the damping orifice passage 24 with respect to vibration during general traveling in the front-rear direction (X-axis direction), and the idle orifice passage 26 with respect to idle vibration on a higher frequency side than this. A low dynamic spring can be realized by liquid column resonance.
[0050]
In addition, since the thin portion 34 that forms the bottom of the straight portion 27 is formed between the lateral vibration isolating portion 2 and the vertical vibration isolating portion 1, the thin portion 34 undergoes membrane resonance, thereby causing the vertical vibration isolating portion. A low dynamic spring can be realized with respect to the vibration in the vertical direction (Z-axis direction) in the vibration part 1. In addition, the damping orifice passage 15 provides high attenuation with respect to vertical vibrations during general travel, and the presence of the elastic film 8a makes it possible to reduce the overall vertical vibrations to a low dynamic spring in a wide frequency range.
[0051]
Therefore, for each vibration in the front-rear direction and the vertical direction, it is possible to simultaneously realize high attenuation with respect to low-frequency large-amplitude vibration during general traveling and low dynamic springs with respect to vibration on the higher frequency side. In addition, if the transverse auxiliary liquid chamber 25 is provided in one of the pair of the straight portions 27, the space of the straight portion 27 can be used effectively, and the apparatus can be downsized.
[0052]
The vibration in the Y-axis direction is absorbed by elastic deformation of the elastic partition wall 35 that forms a kind of rubber spring. As a result, the X-axis direction can be absorbed by the liquid column resonance of the damping orifice passage 24 and the idle orifice passage 26, the Y-axis direction can be absorbed by the elastic partition wall 35, and the Z-axis direction can be absorbed by the longitudinal vibration isolator 1, respectively. Each vibration in the axial direction can be effectively prevented.
[0053]
Further, if the spring constant is adjusted by changing the thickness of the elastic partition wall 35, the vibration absorption performance in the Y-axis direction can be freely adjusted. In the present embodiment, the elastic partition wall 35 is set to be soft due to the formation of the straight portion 27, and the lateral auxiliary liquid chamber 25 is provided in one of the straight portions 27, so that the spring constant is asymmetrical.
[0054]
Next, the internal pressure control will be described. FIG. 6 is a diagram for explaining the operation of the lateral membrane 50. As shown in FIG. 6A, when the working chamber 56 is opened to the atmosphere, the lateral membrane 50 is in a free state free from elastic deformation. For this reason, the spring of the transverse membrane 50 is lowered, and the total spring is also lowered. Therefore, when the internal pressure of the horizontal main liquid chamber 20 fluctuates due to input of vibrations in the front-rear direction or the vertical direction, this internal pressure fluctuation is absorbed by the elastic deformation of the lateral membrane 50 to form a low spring.
[0055]
At this time, if the vibration is small, the elastic deformation of the lateral membrane 50 is completely free, so that the state of the lowest spring is obtained. When the vibration slightly increases and contacts the projection 59, the lateral membrane 50 is surrounded by the projection 59. In order to elastically deform within a small range, the spring of the transverse membrane 50 goes up. When the vibration is further increased, the transverse membrane 50 comes into contact with the seat surface 58 and elastic deformation is restricted, so that the spring is further raised. Therefore, it exhibits a non-linear spring characteristic in which the spring constant changes in multiple steps depending on the magnitude of the input vibration.
[0056]
In particular, when the transverse membrane 50 is connected to the seat surface 58 and the deformation is restricted with respect to low frequency and large amplitude vibration during normal running of about 7 to 15 Hz, the transverse membrane 50 becomes rigid (in the present application, a free state). Since the wall rigidity of the front side main liquid chamber 20A is increased due to a stiffer state, the same applies hereinafter, the amount of liquid flowing into the damping orifice passage 24 is increased, and as a result, the resonance efficiency of the damping orifice passage 24 is increased. High attenuation can be achieved. In addition, since the elastic deformation of the transverse membrane 50 is restricted against large vibration input, durability can be improved.
[0057]
FIG. 7 is a graph in which the horizontal axis represents the frequency and the vertical axis represents the damping coefficient C in order to show the damping performance with respect to the longitudinal vibration in the lateral vibration isolator 2. As is apparent from this graph, the present example (solid line) shows a higher attenuation coefficient C than the comparative example (broken line) lacking the transverse membrane 50. In this low frequency range, the present embodiment can achieve higher attenuation and improve ride comfort.
[0058]
This graph shows the characteristics in the horizontal vibration isolator 2. Also in the vertical vibration isolator 1, the resonance efficiency of the damping orifice passage 15 is improved with respect to vertical vibrations by making the transverse membrane 50 rigid. Therefore, high attenuation can be obtained in either the vertical vibration by the vertical vibration isolator 1 or the longitudinal vibration by the horizontal vibration isolator 2.
[0059]
Next, as shown in B of FIG. 6, when the idle frequency (for example, about 15 to 40 Hz) is reached, the working chamber 56 is set to a negative pressure by the switching valve 57, and the lateral membrane 50 is sucked and adhered to the seat surface 58. As a result, the transverse membrane 50 becomes rigid, so that the total spring is increased, the resonance efficiency of the idle orifice passage 26 is improved, and the dynamic spring is reduced.
[0060]
FIG. 8 shows this, and the dynamic spring constant K can be lowered at the idle frequency in the present embodiment (solid line) compared to the comparative example (broken line). This graph is also a characteristic with respect to the longitudinal vibration in the lateral vibration isolator 2, with the horizontal axis representing the frequency and the vertical axis representing the dynamic spring constant (absolute spring K) (see also FIGS. 9 and 10 below). The same).
[0061]
Further, as shown in FIG. 6C, the working chamber 56 is opened to the atmosphere against medium-high frequency (50 to 1 KHz) vibration due to vibration during acceleration. Moreover, since this vibration has a relatively small amplitude, the transverse membrane 50 is free from deformation restriction by the transverse membrane stopper 53, and the spring of the transverse membrane 50 becomes the lowest, so that the total spring is also lowered.
[0062]
FIG. 9 shows the dynamic spring characteristics with respect to vertical vibrations in the entire apparatus to show the effect of the transverse membrane 50 at medium and high frequencies, and the dynamic spring constant K of this example (solid line) is generally lower than that of the comparative example (dashed line). Thus, a low dynamic spring can be realized in the entire middle and high frequency range shown in the figure.
[0063]
FIG. 10 is a graph in which the vertical axis represents the dynamic spring constant (absolute spring constant) K and the horizontal axis represents the frequency in order to explain the influence of the membrane resonance, and the medium and high frequency (50 to 1 KHz) region similar to FIG. The dynamic spring characteristic with respect to the vertical vibration in is shown. In this graph, liquid was sealed only in each liquid chamber in the horizontal vibration isolator 2 as an upper portion, and the end wall was measured mainly with no liquid sealed in each liquid chamber in the vertical vibration isolator 1. The liquid resonance is sealed only in the liquid chambers of the vertical vibration isolator 1 as the lower part and the liquid chambers of the horizontal vibration isolator 2 are not sealed with the liquid resonance effect of the parts 21A and 21B. What shows the effect of the membrane resonance of the dome part 6 measured mainly in FIG. 5 and what shows the total spring measured in a state where liquid is sealed in the liquid chambers of the longitudinal vibration isolating part 1 and the lateral vibration isolating part 2 It is written together.
[0064]
In this example, the springs of the front end wall 21A and the rear end wall 21B in the upper part are replaced. Specifically, the rear end wall portion 21B is made thicker than the front end wall portion 21A, and the membrane resonance frequency is set such that the front end wall portion 21A <the rear end wall portion 21B <the dome portion, for example, the left side. Thin wall portion 34 <the thin wall portion 34 on the right side of the dome portion, for example.
Set to be. As a result, the upper lateral vibration isolator 2 forms a peak P1 based on the membrane resonance by the front end wall 21A and a peak P2 based on the membrane resonance by the rear end wall 21B on the higher frequency side. . Furthermore, in the vertical vibration isolator 1 which is the lower part, a peak P3 due to the film resonance of the left thin part 34 occurs on the higher frequency side than P2, and further, a peak P4 due to the film resonance of the right thin part 34 on the higher frequency side. Arise.
[0065]
According to this example, after the occurrence of the membrane resonance peaks P1 and P2 due to the end wall portions 21A and 21B in the upper dynamic spring characteristics, the peak of the membrane resonance due to the thin portions 34 of the left and right dome portions 6 in the lower dynamic spring characteristics. P3 and P4 are generated, but the graph of the total spring in which these are coupled is a wide range as shown by the solid line due to the interaction of the peaks P1, P2 and P3, P4 of each membrane resonance. A lower dynamic spring can be realized.
[0066]
Although the theoretical elucidation for the phenomenon of the low dynamic spring in the present embodiment has not been made, in an actual use state in which liquid is sealed in both the vertical vibration isolator 1 and the horizontal vibration isolator 2, When vibration is input to the lateral vibration isolator 2, the change in the hydraulic pressure is exerted on the dome 6 to affect the internal pressure of the vertical main fluid chamber 10, thereby realizing a low dynamic spring. Conceivable.
[0067]
Further, the vibration input to the longitudinal vibration isolator 1 affects the internal pressure of each liquid chamber in the lateral vibration isolator 2 from the dome 6, so that it is considered that the total spring is reduced in dynamic spring. . In any case, due to the interaction between the vertical vibration isolator 1 and the horizontal vibration isolator 2, it is possible to achieve a low dynamic spring of the total spring using the respective membrane resonances. Since the respective membrane resonances in the vertical vibration isolator 1 and the horizontal vibration isolator 2 are generated at a plurality of frequencies, it is possible to achieve broadening that realizes a low dynamic spring in a wide range.
[0068]
Moreover, since the transverse membrane 50 is provided to make the whole as a low spring, when setting the total spring to the same level as the conventional one, either the front and rear end wall portions 21A, 21B and the left and right thin wall portions 34 or the whole Can be made thicker and higher spring. As a result, these membrane resonance frequencies can be shifted to higher frequencies, and a low dynamic spring is possible in a wider frequency range.
[0069]
In addition to the above embodiments, various variations are possible. For example, various combinations in which the thicknesses of the front and rear end wall portions 21A and 21B and the dome portion 6, particularly the thin portion 34 are adjusted are possible. FIG. 11 is a schematic diagram of this embodiment. For convenience, the front side of the end wall 21 is 21A, the rear side is 21B, and the right side of the thin portion 34 of the dome 6 is 34R and the left side is 34L. The upper part of FIG. 11 shows end wall parts 21A and 21B in the front-rear direction, and the lower part shows left and right thin parts 34R and 34L at the same time in the left-right direction.
[0070]
At this time, first, in relation to the thickness of the thin portion, three types of 34A> 34B, 34A = 34B, and 34A <34B are possible. Similarly, the thickness relationship of the end wall portions can be three ways: 21A> 21B, 21A = 21B, 21A <21B. Therefore, a total of nine combinations are possible in the combination of the thin wall portion and the end wall portion.
[0071]
Thus, by changing various thicknesses, it is possible to freely set the directivity with respect to the vibration directions of the front and rear, left and right, and top and bottom, as well as various combinations of the membrane resonance frequencies. As a result, these coupled effects Therefore, the direction of vibration to be damped can be freely set, and a wider range of low dynamic springs can be realized.
[0072]
Further, the lateral membrane 50 can be provided not only on the front lateral main liquid chamber 20A but also on the rear side or front and rear. In addition, the front and rear horizontal main liquid chambers 20A and 20B are merely examples, and can be left and right. Further, as in the above-described embodiment, the main liquid chambers may be more than the front and rear (or left and right) two chambers, and in this case, the transverse membrane 50 may be provided with a plurality of two or more. Further, the lateral membrane 50 may be forcibly elastically deformed by driving a solenoid or a motor as well as the internal pressure control means using the intake negative pressure. This makes it possible to perform electrical control with excellent responsiveness.
[0073]
Next, a second embodiment will be described. In addition, the same code | symbol is used for the part which is common in the previous Example, and the overlapping description is abbreviate | omitted in principle. An embodiment constructed in an engine mount of a vehicle will be described based on the drawings. 12 is a diagram corresponding to FIG. 2, FIG. 13 is a diagram corresponding to FIG. 4, and FIG. 14 is a diagram corresponding to FIG.
[0074]
As is apparent from FIG. 12, the end wall 21 of the lateral vibration isolator 2 is substantially disk-shaped as a whole, and is different in that the straight portions 27R and 27L as in the previous embodiment are not formed. As shown in FIG. 13, a lateral elastic partition wall 70R is provided between the front and rear two of the four elastic partition walls 35 constituting the front lateral main liquid chamber 20A and the rear lateral main liquid chamber 20B. A lateral elastic partition wall 70L is provided between the left and right front and rear two. Both lateral elastic partition walls 70 R and 70 L extend to the opposite side in the left-right direction across the first mounting member 3, and are integrally formed as a part of the elastic main body 5, like the elastic partition wall 35.
[0075]
The cross-sectional areas of the lateral elastic partition walls 70R and 70L are several times larger than the elastic partition wall 35, the left and right directions are made extremely high springs, and vibrations in the Y-axis direction are mainly used for the lateral elastic partition walls 70R and 70L. Absorbs due to elastic deformation. The front ends of both lateral elastic partition walls 70R and 70L are fitted with connecting convex portions 72R and 72L formed integrally with the liquid chamber covers 71R and 71L, respectively, and the two front and rear elastic partition walls 35 and the lateral elastic partition are formed on the right side. The right front lateral liquid chamber 20C and the right rear lateral liquid chamber 20D between the walls 70R, and the left front lateral liquid chamber 20E and the left rear lateral liquid chamber between the two front and rear elastic partition walls 35 and the lateral elastic partition wall 70L. 20F.
[0076]
The right liquid chamber cover 71R and the left liquid chamber cover 71L are substantially semicircular arc members made of a suitable material such as a resin, and are closely fitted to the inner peripheral surface of the second mounting member 4, and the lateral membrane 50 Together with this, one arc is formed as a whole. The right liquid chamber cover 71R and the left liquid chamber cover 71L are also in close contact with the ends of the elastic partition walls 35, and the communication with the right front lateral liquid chamber 20C is established between the close portions and the connecting convex portions 72R and 72L. A communication port 74R to the port 73R and the right rear lateral liquid chamber 20D, a communication port 73L to the left front lateral liquid chamber 20E, and a communication port 74L to the left rear lateral liquid chamber 20F are formed.
[0077]
The communication ports 73R and 74R communicate with each other through a right idle orifice passage 75R, permitting liquid flow between the right front lateral liquid chamber 20C and the right rear lateral liquid chamber 20D, and tuning the resonance point to the idle frequency. . The communication ports 73L and 74L are also communicated with each other through the left idle orifice passage 75L, allowing liquid flow between the left front lateral liquid chamber 20E and the left rear lateral liquid chamber 20F, and tuning the resonance point to the idle frequency. .
[0078]
The right idle orifice passage 75R and the left idle orifice passage 75L are respectively formed between grooves formed in the outer peripheral portions of the right liquid chamber cover 71R and the left liquid chamber cover 71L and the inner peripheral surface of the second mounting member 4. Is formed.
[0079]
On the other hand, in the illustrated state of the right idle orifice passage 75R and the left idle orifice passage 75L, the right damping orifice passage 76R and the left damping orifice passage 76L are provided to overlap each other. The right damping orifice passage 76R communicates with the front side main liquid chamber 20A through a communication port 77R formed at a connection portion between the front end portion of the right liquid chamber cover 71R and the front elastic partition wall 35 in the vicinity of the right end portion of the transverse membrane 50. The communication is communicated with the rear lateral main liquid chamber 20B through a communication port 78R provided at the rear end of the right liquid chamber cover 71R.
[0080]
The left damping orifice passage 76L is connected to the front side main liquid chamber 20A through a communication port 77L formed at a connection portion between the front end portion of the left liquid chamber cover 71L and the front elastic partition wall 35 in the vicinity of the left end portion of the lateral membrane 50. It communicates with the rear lateral main liquid chamber 20B through a communication port 78L provided at the rear end of the left liquid chamber cover 71L. The rear ends of the right liquid chamber cover 71R and the left liquid chamber cover 71L are in contact with an intermediate portion of the rear side main liquid chamber 20B that is an extension of the pipe portion 54, and the communication port 78R and the communication port 78L are integrated. Yes.
[0081]
The right damping orifice passage 76R and the left damping orifice passage 76L are both smaller and longer than the right idle orifice passage 75R and the left idle orifice passage 75L. The resonance point is adapted to the input vibration in the low frequency range during general traveling lower than each resonance point of the orifice passage 75L.
[0082]
As shown in FIG. 14, the front end of the left lateral elastic partition wall 70L has a concave portion 79, and a coupling convex portion 72L is fitted in the concave portion 79, and is made fluid-tight by a seal 80 integrally formed in the vertical direction in the figure. It joins and the front-end | tip of the left side elastic partition wall 70L is slidable on the connection convex part 72L. The same applies to the relationship between the right lateral elastic partition wall 70R and the connecting projection 72R. In addition, a seal 81 is also formed on the front end surface of each elastic partition wall 35 in the vertical direction so as to be liquid-tightly joined to the right or left liquid chamber cover 71L.
[0083]
In the present embodiment, the vibration in the front-rear direction is mainly prevented, and when the vibration in the front-rear direction occurs, the liquid passes through the left and right idle orifice passages 75L and 75R and the right front lateral liquid chamber 20C and the right rear lateral It moves between the liquid chambers 20D and between the left front horizontal liquid chamber 20E and the left rear horizontal liquid chamber 20F, and the liquid column resonates at the idle orifice frequency to become a low dynamic spring. Further, the fluid flows between the front lateral main liquid chamber 20A and the rear lateral main liquid chamber 20B through the left and right damping orifice passages 76L and 76R, and also causes liquid column resonance at a predetermined low frequency, resulting in high attenuation.
[0084]
At this time, the lateral membrane 50 and the internal pressure control means have the same configuration as in the previous embodiment and function in the same manner as in the previous embodiment. That is, the internal pressure control restrains the transverse membrane 50 at the resonance frequency of the idle orifice passages 75L and 75R. Then, since the wall rigidity of the front side main liquid chamber 20A is increased, the wall rigidity of the elastic partition wall 35 between the front side main liquid chamber 20A, the right side front liquid chamber 20C, and the left side front liquid chamber 20E is also increased. As a result, the wall rigidity of the right front lateral liquid chamber 20C and the left front lateral liquid chamber 20E is increased, and the resonance efficiency of the idle orifice passages 75L and 75R is improved.
[0085]
Further, the transverse membrane 50 may be constrained even at the resonance frequency of the damping orifice passages 76L and 76R. Since the end wall 21 has a substantially disk shape, the front and rear end wall portions 21A and 21B are portions that are located above the front side main liquid chamber 20A and the rear side main liquid chamber 20B, respectively. The thin portion 34 is a front portion or a rear portion of the dome portion 6 constituting the front side main liquid chamber 20A and the rear side main liquid chamber 20B instead of the left and right of the previous embodiment.
[0086]
Further, in this embodiment, the liquid chambers 20A and 20B are designated as main liquid chambers, and the names are different from those of the other liquid chambers 20C to 20F. However, this is the same for the liquid chambers 20A and 20B particularly in correspondence with the previous embodiment. Each of the liquid chambers 20A to 20F constitutes a horizontal liquid chamber having no difference between main and sub functions.
[Brief description of the drawings]
1 is a cross-sectional view taken along line 1-1 of FIG. 2 of an engine mount according to an embodiment.
FIG. 2 is a plan view of an engine mount according to the embodiment.
3 is a sectional view taken along line 1-3 of FIG.
4 is a cross-sectional view taken along line 4-4 of FIG.
FIG. 5 is a perspective view of an insertion body.
FIG. 6 is a diagram for explaining the operation of the transverse membrane
FIG. 7 is a graph showing attenuation characteristics.
FIG. 8 is a graph showing dynamic spring characteristics during idling
FIG. 9 is a graph showing dynamic spring characteristics in the middle and high frequency range.
FIG. 10 is a graph showing dynamic spring characteristics of each part together
FIG. 11 is a schematic diagram showing combinations of wall thickness changes of elastic walls.
FIG. 12 is a diagram corresponding to FIG. 2 according to the second embodiment.
FIG. 13 is a diagram corresponding to FIG. 4 according to the second embodiment.
FIG. 14 is a diagram corresponding to FIG. 5 according to the second embodiment.
[Explanation of symbols]
1: vertical vibration isolator, 2: horizontal vibration isolator, 3: first mounting member, 4: second mounting member, 5: elastic main body, 6: dome, 7: elastic main body, 8 : Partition member, 8a: elastic membrane, 10: vertical main liquid chamber, 11: vertical sub liquid chamber, 15: damping orifice passage, 20A: front main liquid chamber, 20B: rear main liquid chamber, 21A: front end wall , 21B: rear end wall, 22: liquid chamber cover, 24: damping orifice passage, 25: transverse auxiliary liquid chamber, 26: idle orifice passage, 27: straight portion, 34: thin portion, 35: elastic partition wall, 36: outer side wall, 50: lateral membrane, 53: lateral membrane stopper, 56: working chamber

Claims

A liquid seal anti-vibration device in which a vertical vibration isolator that mainly isolates main vibration and a horizontal anti-vibration unit that mainly anti-vibrates in a direction orthogonal to the input direction of the main vibration. The directional vibration isolator has an elastic member in the main vibration input direction, a vertical main liquid chamber having the elastic member as a part of a wall, and a vertical auxiliary liquid chamber communicating with the vertical main liquid chamber via an orifice passage. Arrange
In the lateral vibration isolator, a plurality of horizontal liquid chambers are arranged in a plane perpendicular to the main vibration input direction, and these horizontal liquid chambers communicate with each other through an orifice passage.
The elastic wall constituting the vertical main liquid chamber of the vertical vibration isolator forms part of the elastic wall constituting each horizontal liquid chamber of the horizontal vibration isolator,
At least one of the lateral liquid chambers constituting the lateral vibration isolating portion is provided with an internal pressure control means for controlling the internal pressure ,
The internal pressure control means includes a movable film that is elastically deformed by fluctuations in the internal pressure of the lateral liquid chamber, and a movable film stopper that restricts deformation of the movable film, and is free or movable to freely elastically deform the movable film. A liquid seal vibration isolator which is switched to a constrained state to be fixed on a film stopper .

Said movable membrane stopper, in unconstrained state of the movable film, by changing the spring constant is brought into contact with said movable membrane, according to claim 1, characterized in that impart spring characteristics of the nonlinear said movable membrane Liquid seal vibration isolator as described in 1.

2. The liquid seal vibration-proofing according to claim 1 , wherein the internal pressure control means controls the working chamber formed between the movable film and the movable film stopper by switching to an atmospheric pressure or an intake negative pressure. apparatus.

2. The liquid seal vibration isolator according to claim 1 , wherein the internal pressure control means controls the movable film by driving it with a solenoid or a motor.

The liquid seal vibration isolator according to any one of claims 1 to 4 , wherein the movable film is formed separately from another elastic member constituting the horizontal liquid chamber.

2. The liquid seal vibration isolator according to claim 1, wherein the orifice passage in the lateral vibration isolator includes at least first and second orifice passages having different resonance frequencies.

The thickness of the elastic wall constituting at least a part of the elastic walls constituting the liquid chambers of the vertical vibration isolator and the horizontal vibration isolator is the thickness of the elastic wall constituting the other liquid chamber. The liquid seal vibration isolator according to claim 1, wherein the liquid seal vibration isolator is different.