JP2592077C

JP2592077C -

Info

Publication number: JP2592077C
Authority: JP
Original assignee: Kinugawa Rubber Industrial Co Ltd
Current assignee: Kinugawa Rubber Industrial Co Ltd
Publication date: 1998-09-24

Description

【発明の詳細な説明】産業上の利用分野この発明は、主に自動車のエンジンマウント等として用いられる流体封入型防
振装置に関する。従来の技術エンジンマウントに好適な流体封入型防振装置として、例えば特開昭５６−１
２４７３９号公報に記載のものが知られている。これは、例えば車体側に固定さ
れる軸部材と、これを囲んで配設され、かつ例えばエンジン側に固定される外筒
部材と、両者間に挿填されたゴム体とを有し、上記ゴム体の内部に３個の液室が
画成されているとともに、これらの液室を、軸部材内部のオリフィス通路で互い
に連通した構成となっている。すなわち、軸部材と外筒部材とが相対変位すると、ゴム体の弾性変形に伴って
各液室の容積が変化し、これにより各液室内に封入されたエチレングリコール等
の液体が上記オリフィス通路を通して移動する結果、単にゴム体のみを備えた防
振装置に比べて非常に大きな減衰作用が得られるのである。発明が解決しようとする問題点ところで、一般にエンジンマウントにおいては、低周波域での振幅の大きな振
動に対して十分な減衰作用を果たすべく低周波域でのロスファクタが大きいことが望ましく、他方、高周波の微小振動を車体側に伝達しないように、高周波域で
の動ばね定数が小さいことが望ましい。すなわち、低周波域でロスファクタが大
きく、かつ高周波域で動ばね定数が小さい特性が望まれる。しかしながら、上記従来の流体封入型防振装置においては、３個の液室が全て
同一のオリフィス通路を介して互いに連通しており、ロスファクタや動ばね定数
の特性をある一つの周波数に対してしかチューニングすることができない。通常
は、低周波域での振動減衰特性が重視されるため、１０Ｈｚ程度の低周波数にチ
ューニングされることになり、従って、第１１図に示すように、例えば１００Ｈ
ｚ以上の高周波域での動ばね定数Ｋｄがかなり大きくなってしまう。そのため、
この高周波域での微小なエンジン振動を十分に遮断できないという欠点があった
。問題点を解決するための手段上記の問題点を解決するために、この発明に係る流体封入型防振装置は、軸部
材とこれを囲む外筒部材との間に挿填されたゴム体の内部に、少なくとも３個の
液室を画成するとともに、これらの液室を個々にオリフィス通路を介して連通さ
せて少なくとも２つの振動系を構成し、かつ各振動系を構成するオリフィス通路
の通路断面積および通路長で定まる等価質量を各振動系で異なる値に設定したも
のである。すなわち、第１の発明は、軸部材とこれを囲む外筒部材との間にゴム体が挿填
されてなる液体封入型防振装置であって、上記ゴム体の一部をなし、かつ上記軸
部材と上記外筒部材とを互いに支持するように、上記軸部材から放射状に延びた
一対の主弾性部と、上記ゴム体の内部で上記主弾性部の挟角側に形成された主液
室と、上記軸部材を挟んで上記主液室と対称となる位置に設けられ、かつゴム体
を軸方向に貫通した空隙部と、上記ゴム体の内部で上記空隙部に隣接する位置に
形成された第１および第２の副液室と、上記外筒部材に周方向に沿って形成され
、上記主液室と第１の副液室とを連通する第１のオリフィス通路と、上記外筒部
材に周方向に沿って形成され、上記主液室と第２の副液室とを連通するとともに
、上記第１のオリフィス通路よりも通路長が短く通路断面積が大きい第２のオリ
フィス通路と、を備え、上記第１のオリフィス通路は、主液室の上記第１の副液
室寄りとなる周方向の一端部に接続され、かつここから主液室の外周側ならびに
第２の副液室の外周側を通って延びており、また上記第２のオリフィス通路は、主
液室の上記第２の副液室寄りとなる周方向の他端部に接続され、第１の副液室の
外周側を通ることなく該主液室と第２の副液室とを連通している。また第２の発明は、軸部材とこれを囲む外筒部材との間にゴム体が挿填されて
なる液体封入型防振装置であって、上記ゴム体の一部をなし、かつ上記軸部材と
上記外筒部材とを互いに支持するように、上記軸部材から放射状に延びた一対の
主弾性部と、同じく上記ゴム体の一部をなし、かつ上記一対の主弾性部に挟まれ
た挟角側の部分に形成された隔壁と、上記ゴム体の内部で上記主弾性部と上記隔
壁との間にそれぞれ形成された一対の主液室と、上記軸部材を挟んで上記主液室
と対称となる位置に設けられ、かつゴム体を軸方向に貫通した空隙部と、上記ゴ
ム体の内部で上記空隙部に隣接する位置に形成された一対の副液室と、一つの主
液室と一つの副液室とを連通する第１のオリフィス通路と、他の主液室と他の副
液室とを連通し、かつ上記第１のオリフィス通路よりも通路長が短く通路断面積
が大きい第２のオリフィス通路と、を備えている。作用一般に流体封入型防振装置は、液柱の共振現象を利用したものであり、その共
振周波数はオリフィス通路の等価質量と液室の拡張ばね定数によって定まるので
、上記のようにオリフィス通路の等価質量を異ならせることにより、各振動系の
共振周波数は異なるものとなる。すなわち、ある１つのオリフィス通路の通路断面積を比較的小さく、かつ通路
長を比較的長く設定すれば、等価質量は大となり、その振動系は低周波域で共振
する。従って、低周波域でのロスファクタが大きく得られる。また、他の１つのオリフィス通路の通路断面積を比較的大きく、かつ通路長を
比較的短く設定すれば、等価質量は小となり、その振動系は高周波域で共振する
。従って、高周波域での動ばね定数が非常に小さなものとなる。ここで、上記構成では、軸部材と外筒部材とが相対的に変位すると、略Ｖ字形
をなす主弾性部の内側に形成された主液室の容積が変化し、副液室との間で各オ
リフィス通路を介して液体が確実に移動する。実施例第１図〜第５図は、例えばエンジンマウントとして用いられる本発明の流体封
入型防振装置の一実施例を示している。図において、１は例えば車体側に固定される金属製の軸部材、２はこの軸部材
１を囲むように配設され、かつ例えばエンジン側に固定される円筒状をなす金属
製の外筒部材、３は両者間に挿填されたゴム体である。この実施例では、上記外筒部材２は、インナカラー４とアウタカラー５と両者
間に介在する中間カラー６との三重構造となっている。そして、上記インナカラ
ー４と中間カラー６は互いに密に圧入固定されており、またアウタカラー５は、
中間カラー６の外周に圧入された上で、両端縁５ａをかしめて固定してある（第
２図参照）。上記ゴム体３は、その内周側が上記軸部材１に加硫接着されており、かつ外周
側が上記外筒部材２、詳しくはインナカラー４に加硫接着されている。そして、
このゴム体３の内部に、３個の液室、つまり主液室となる第１液室７と、第１の
副液室となる第２液室８および第２の副液室となる第３液室９が画成されている
。詳しくは、第１液室７は、ゴム体３の下部中央に比較的大きく形成されており
、また第２，第３液室８，９は、上記第１液室７よりも容積が小さく、それぞれ
軸部材１の両側に対称形状に形成されていて、第１液室７と第２，第３液室８，
９との間に、逆Ｖ字形の主弾性部３ａが残るようにしてある。つまり、上記軸部
材１は主に上記主弾性部３ａを介して外筒部材２に支持されるのであり、エンジ
ンの荷重が作用した状態で軸部材１と外筒部材２とがちょうど同心状となるよう
に構成されている。また、上記ゴム体３の上部には、円弧状に空隙部１０が貫通
形成されている。なお、１１は上記ゴム体３の中心部分を補強するとともに、過
大な変位を阻止すべくゴム体３内に埋設された金属製のストッパである。一方、上記インナカラー４においては、第５図に示すように、各液室７，８，
９に対応する部分が矩形の窓状に開口形成されている。つまり、この各液室７，
８，９の部分では、側端部４ａのみが帯状に残されている（第２図参照）。そし
て、上記インナカラー４の外周に嵌合する中間カラー６の外周面に、第１オリフ
ィス通路１２と第２オリフィス通路１３とが凹設されている。上記第１オリフィス通路１２は、第１図に示すように、中間カラー６の略全周近くに亘って形成され、つまり通路長が十分に長く形成されており、一端が開口
部１４を介して第１液室７に連通し、かつ他端が開口部１５を介して第２液室８
に連通している。そして、この第１液室７と第２液室８とを連通した第１オリフ
ィス通路１２は、第２図に示すように、その通路断面積が比較的小さく設定され
ている。なお、上記開口部１４，１５は、上記第１オリフィス通路１２の通路長
が最も長くなるように、それぞれ第１液室７，第２液室８の端部に開口している
。従って、上記第１オリフィス通路１２の等価質量は非常に大きなものとなる。また上記第２オリフィス通路１３は、第３図に示すように、第１液室７と第３
液室９とを直接につなぐ形に、つまり通路長が短く形成されており、一端が開口
部１６を介して第１液室７に連通し、かつ他端が開口部１７を介して第３液室９
に連通している。そして、第４図に示すように、この第２オリフィス通路１３は
広い幅に形成されており、つまりその通路断面積が比較的大きく設定されている
。なお、上記開口部１６，１７は、上記第２オリフィス通路１３が最も短くなる
ような位置に開口している。従って、上記第２オリフィス通路１３の等価質量は
非常に小さなものとなる。上記のように第１オリフィス通路１２，第２オリフィス通路１３によって連通
された各液室７，８，９の内部には、適宜な粘度、例えば２００ＣＰ程度のエチ
レングリコール等が密に充填されている。さて上記のように構成された流体封入型防振装置においては、軸部材１が外筒
部材２に対し相対変位すると、各液室７，８，９内の容積が変化し、第１液室７
と第２液室８との間、および第１液室７と第３液室９との間で液体が移動する。
このとき、第１液室７と第２液室８とは、等価質量が大きいオリフィス通路つま
り通路断面積が小さく、かつ通路長が長い第１オリフィス通路１２で連通されて
いるため、低周波域で共振して第１オリフィス通路１２内を多量の液体が通過す
る。従って、第１２図の破線に示すように、１０Ｈｚ前後の低周波域で非常に大
きなロスファクタlが得られ、エンジンの大振幅の振動を効果的に抑制できる。一方、第１液室７と第３液室９とは、等価質量が小さなオリフィス通路つまり
通路断面積が大きく、かつ通路長が短い第２オリフィス通路１３で連通されてい
るため、高周波域で共振して第２オリフィス通路１３内を多量の液体が通過する
。従って、第１２図の実線に示すように、高周波域での動ばね定数Ｋｄを小さなも
のとすることができ、車体への微小振動の伝達を効果的に阻止できる。なお、第
１２図の例では、高周波側のピークが２００Ｈｚ前後にチューニングされている
が、これは第２オリフィス通路１３の通路断面積や通路長によって適宜変更し得
るのは勿論である。因みに、上記実施例においては、第１オリフィス通路１２の断面積は７mm²、
長さは１５０mm程度に設定されており、また第２オリフィス通路１３の断面積は
５０mm²、長さは１５mm程度に設定されている。第１０図は、上述した作用の理解を助けるために、上記流体封入型防振装置の
振動系をモデル化して示したものである。ここで、ｋはゴム体３のばね定数、ｋ
₁は第１液室７の拡張ばね定数、ｋ₂は第２液室８および第３液室９の拡張ばね定
数を示している。次に、第６図〜第９図は、この発明に係る流体封入型防振装置の異なる実施例
を示している。この実施例は、外筒部材２がインナカラー４とアウタカラー１８
との二重構造となっており、両者は密に圧入されて互いに固定されている。そし
て、上記アウタカラー１８の内周面に第１オリフィス通路１９および第２オリフ
ィス通路２０が凹設されている。第１液室７と第２液室８とを連通する第１オリフィス通路１９は、やはり通路
断面積が比較的小さく設定され（第７図参照）、かつ通路長を長く確保すべくア
ウタカラー１８を略一周するように形成されているもので、特に第７図に示すよ
うに、インナカラー４の帯状の側端部４ａによって覆われ得る位置に形成されて
いる。そして、その両端部に、アウタカラー１８の軸方向に折曲した折曲部２１
，２２が設けられており、該折曲部２１，２２を介して第１液室７および第２液
室８にそれぞれ連通している。また、第１液室７と第３液室９とを連通する第２オリフィス通路２０は、イン
ナカラー４の第１液室７，第３液室９に対応した窓状開口部と両端が一部ラップ
するように形成されており、この結果、液室７，９内に露出した端部２０ａ，２
０ｂを介して第１液室７および第３液室９にそれぞれ連通している。なお、上記
第２オリフィス通路２０は、第９図に示すように、十分に大きな通路断面積を有している。この実施例では、アウタカラー１８に対する第１オリフィス通路１９，第２オ
リフィス通路２０の溝加工が若干面倒になるものの、外筒部材２が二重構造とな
り、部品点数を削減できる利点がある。次に、第１３図に示す実施例は、ゴム体３内部に４個の液室を画成した実施例
を示している。すなわち、逆Ｖ字形をなす主弾性部３ａの下部に、略垂直な隔壁
２３を挟んで第１液室２４と第２液室２５とが対称形状に形成されているととも
に、主弾性部３ａの上部に、第３液室２６と第４液室２７とが対称形状に形成さ
れている。そして、主液室となる第１液室２４と副液室となる第３液室２６とが
細くかつ長い第１オリフィス通路２８を介して連通しており、かつ主液室となる
第２液室２５と副液室となる第４液室２７とが太くかつ短い第２オリフィス通路
２９を介して連通している。従って、上記実施例では、第１液室２４と第３液室２６と第１オリフィス通路
２８とによって一方の振動系が構成され、かつ第２液室２５と第４液室２７と第
２オリフィス通路２９とによって他方の振動系が構成される。そして、第１オリ
フィス通路２８の等価質量が第２オリフィス通路２９の等価質量よりも大となり
、この結果、第１オリフィス通路２８側の振動系が比較的低周波域で共振し、か
つ第２オリフィス通路２９側の振動系が比較的高周波域で共振することになる。なお、上記のように多数の液室を備えたものにおいては、各液室の連通の態様
を変えることで種々の組み合わせが可能である。発明の効果以上の説明で明らかなように、この発明に係る流体封入型防振装置によれば、
低周波域でのロスファクタを十分に大きく確保できると同時に、高周波域での動
ばね定数を小さく抑制することができる。従って、低周波域にチューニングした
従来の防振装置に比べて、高周波振動を一層効果的に遮断でき、例えばエンジン
マウントとしてエンジン振動に起因する騒音の低減が図れる。特に、主液室が略
Ｖ字形をなす主弾性部の挟角側に配置され、その対称位置に空隙部が位置するの
で、入力に対し主液室が確実に容積変化し、液柱振動による振動抑制作用が一層
良好に得られる。 Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fluid filled type vibration damping device mainly used as an engine mount of an automobile. 2. Description of the Related Art As a fluid-filled vibration isolator suitable for an engine mount, for example,
No. 24739 is known. This includes, for example, a shaft member fixed to the vehicle body side, an outer cylinder member arranged around the shaft member and fixed to the engine side, for example, and a rubber body inserted therebetween. Three liquid chambers are defined inside the rubber body, and these liquid chambers are configured to communicate with each other through an orifice passage inside the shaft member. That is, when the shaft member and the outer cylinder member are relatively displaced, the volume of each liquid chamber changes due to the elastic deformation of the rubber body, whereby the liquid such as ethylene glycol sealed in each liquid chamber passes through the orifice passage. As a result of the movement, an extremely large damping effect can be obtained as compared with a vibration isolator having only a rubber body. Problems to be Solved by the Invention By the way, in general, in an engine mount, it is desirable that a loss factor in a low frequency range is large in order to perform a sufficient damping action against a large amplitude vibration in a low frequency range. It is desirable that the dynamic spring constant in a high frequency range be small so that high-frequency minute vibrations are not transmitted to the vehicle body. That is, it is desired that the loss factor be large in a low frequency range and the dynamic spring constant be small in a high frequency range. However, in the above-mentioned conventional fluid-filled type vibration damping device, all three liquid chambers communicate with each other through the same orifice passage, and the characteristics of the loss factor and the dynamic spring constant for a certain frequency. You can only tune. Normally, since the vibration damping characteristics in the low frequency range are emphasized, tuning to a low frequency of about 10 Hz is performed. Therefore, as shown in FIG.
The dynamic spring constant Kd in the high frequency range of z or more becomes considerably large. for that reason,
There is a drawback that the minute engine vibration in this high frequency range cannot be cut off sufficiently. Means for Solving the Problems In order to solve the above problems, a fluid-filled type vibration damping device according to the present invention includes a rubber member inserted between a shaft member and an outer cylinder member surrounding the shaft member. Inside, at least three liquid chambers are defined, and these liquid chambers are individually communicated via orifice passages to form at least two vibration systems, and passages of the orifice passages constituting each vibration system The equivalent mass determined by the cross-sectional area and the passage length is set to a different value for each vibration system. That is, a first invention is a liquid-enclosed type vibration damping device in which a rubber member is inserted between a shaft member and an outer cylindrical member surrounding the shaft member, and forms a part of the rubber member. A pair of main elastic portions radially extending from the shaft member so as to support the shaft member and the outer cylindrical member with each other; and a main liquid formed inside the rubber body on a narrow angle side of the main elastic portion. Chamber, a gap portion provided symmetrically with the main liquid chamber with the shaft member interposed therebetween, and a gap portion penetrating the rubber body in the axial direction, and formed at a position adjacent to the gap portion inside the rubber body. A first orifice passage formed in the outer cylinder member along the circumferential direction, and communicating with the main liquid chamber and the first sub liquid chamber; The first orifice is formed in the cylinder member along the circumferential direction to communicate the main liquid chamber and the second sub liquid chamber. A second orifice passage having a passage length shorter than the passage and having a larger passage cross-sectional area, wherein the first orifice passage is provided at one end in a circumferential direction of the main liquid chamber which is closer to the first sub liquid chamber. And the second orifice passage extends from the main liquid chamber to the outer peripheral side of the main liquid chamber and the outer peripheral side of the second sub liquid chamber. The main liquid chamber and the second sub liquid chamber communicate with each other without passing through the outer peripheral side of the first sub liquid chamber. Further, a second invention is a liquid-filled type vibration damping device in which a rubber member is inserted between a shaft member and an outer cylindrical member surrounding the shaft member, wherein the rubber member is a part of the rubber member, and A pair of main elastic portions radially extending from the shaft member and also form a part of the rubber body, and are sandwiched between the pair of main elastic portions so as to support the member and the outer cylinder member with each other. A partition wall formed at the included angle side, a pair of main liquid chambers respectively formed between the main elastic portion and the partition wall inside the rubber body, and the main liquid chamber sandwiching the shaft member And a pair of sub-liquid chambers formed at positions adjacent to the gap inside the rubber body, and a single main liquid. A first orifice passage communicating the chamber with one auxiliary liquid chamber, another main liquid chamber and another auxiliary liquid chamber, and Serial passage length than the first orifice passage is provided with a second orifice passage is large short cross-sectional area, the. Function Generally, the fluid-filled type vibration damping device utilizes the resonance phenomenon of the liquid column, and its resonance frequency is determined by the equivalent mass of the orifice passage and the expansion spring constant of the liquid chamber. By making the mass different, the resonance frequency of each vibration system becomes different. That is, if the cross-sectional area of one orifice passage is set relatively small and the passage length is set relatively long, the equivalent mass becomes large and the vibration system resonates in a low frequency range. Therefore, a large loss factor in a low frequency range can be obtained. If the cross-sectional area of the other orifice passage is set relatively large and the passage length is set relatively short, the equivalent mass becomes small, and the vibration system resonates in a high frequency range. Therefore, the dynamic spring constant in a high frequency range becomes very small. Here, in the above configuration, when the shaft member and the outer cylinder member are relatively displaced, the volume of the main liquid chamber formed inside the substantially elastic V-shaped main elastic portion changes, and the volume between the main liquid chamber and the sub liquid chamber changes. As a result, the liquid reliably moves through each orifice passage. Embodiment FIGS. 1 to 5 show an embodiment of a fluid filled type vibration damping device of the present invention used as, for example, an engine mount. In the drawing, reference numeral 1 denotes a metal shaft member fixed to, for example, a vehicle body side, and 2 denotes a cylindrical metal outer cylinder member disposed around the shaft member 1 and fixed to, for example, an engine side. Reference numeral 3 denotes a rubber body inserted between the two. In this embodiment, the outer cylinder member 2 has a triple structure of an inner collar 4, an outer collar 5, and an intermediate collar 6 interposed therebetween. The inner collar 4 and the intermediate collar 6 are tightly press-fitted and fixed to each other, and the outer collar 5 is
After being pressed into the outer periphery of the intermediate collar 6, both end edges 5a are caulked and fixed (see FIG. 2). The rubber body 3 has an inner peripheral side vulcanized and bonded to the shaft member 1 and an outer peripheral side vulcanized and bonded to the outer cylindrical member 2, specifically, the inner collar 4. And
Inside the rubber body 3, three liquid chambers, that is, a first liquid chamber 7 serving as a main liquid chamber, a second liquid chamber 8 serving as a first auxiliary liquid chamber, and a second liquid chamber 8 serving as a second auxiliary liquid chamber are provided. A three-liquid chamber 9 is defined. Specifically, the first liquid chamber 7 is formed relatively large in the lower center of the rubber body 3, and the second and third liquid chambers 8 and 9 have a smaller volume than the first liquid chamber 7, The first liquid chamber 7 and the second and third liquid chambers 8 are formed symmetrically on both sides of the shaft member 1, respectively.
9, the main elastic portion 3a having an inverted V-shape remains. That is, the shaft member 1 is mainly supported by the outer cylinder member 2 via the main elastic portion 3a, and when the load of the engine is applied, the shaft member 1 and the outer cylinder member 2 are just concentric. It is configured to be. In the upper part of the rubber body 3, a gap 10 is formed in an arc shape so as to penetrate therethrough. Reference numeral 11 denotes a metal stopper embedded in the rubber body 3 to reinforce the center portion of the rubber body 3 and prevent excessive displacement. On the other hand, in the inner collar 4, as shown in FIG.
The portion corresponding to No. 9 is formed in the shape of a rectangular window. That is, each of the liquid chambers 7,
In portions 8 and 9, only the side end 4a is left in a band shape (see FIG. 2). A first orifice passage 12 and a second orifice passage 13 are recessed on the outer peripheral surface of the intermediate collar 6 fitted on the outer periphery of the inner collar 4. As shown in FIG. 1, the first orifice passage 12 is formed over substantially the entire circumference of the intermediate collar 6, that is, the passage length is formed sufficiently long, and one end is formed through the opening 14. The second liquid chamber 8 communicates with the first liquid chamber 7 and has the other end through the opening 15.
Is in communication with As shown in FIG. 2, the first orifice passage 12 communicating the first liquid chamber 7 and the second liquid chamber 8 has a relatively small cross-sectional area. The openings 14 and 15 are opened at the ends of the first liquid chamber 7 and the second liquid chamber 8, respectively, so that the path length of the first orifice path 12 is the longest. Therefore, the equivalent mass of the first orifice passage 12 becomes very large. Further, as shown in FIG. 3, the second orifice passage 13 is connected to the first liquid chamber 7 and the third
The liquid chamber 9 is directly connected to the liquid chamber 9, that is, the passage length is short. One end communicates with the first liquid chamber 7 through the opening 16, and the other end communicates with the third liquid through the opening 17. Liquid chamber 9
Is in communication with As shown in FIG. 4, the second orifice passage 13 is formed to have a wide width, that is, the passage cross-sectional area is set to be relatively large. The openings 16 and 17 are open at positions where the second orifice passage 13 is the shortest. Therefore, the equivalent mass of the second orifice passage 13 is very small. As described above, the inside of each of the liquid chambers 7, 8, and 9 communicated by the first orifice passage 12 and the second orifice passage 13 is densely filled with an appropriate viscosity, for example, ethylene glycol of about 200 CP. . In the fluid filled type vibration damping device configured as described above, when the shaft member 1 is relatively displaced with respect to the outer cylinder member 2, the volumes in the respective liquid chambers 7, 8, 9 change, and the first liquid chamber is changed. 7
The liquid moves between the first liquid chamber 8 and the second liquid chamber 8 and between the first liquid chamber 7 and the third liquid chamber 9.
At this time, the first liquid chamber 7 and the second liquid chamber 8 communicate with each other through the orifice passage having a large equivalent mass, that is, the first orifice passage 12 having a small passage cross-sectional area and a long passage length. And a large amount of liquid passes through the first orifice passage 12. Therefore, as shown by the broken line in FIG. 12, a very large loss factor 1 is obtained in a low frequency range of about 10 Hz, and large-amplitude vibration of the engine can be effectively suppressed. On the other hand, the first liquid chamber 7 and the third liquid chamber 9 communicate with each other through the orifice passage 13 having a small equivalent mass, that is, the second orifice passage 13 having a large passage cross-sectional area and a short passage length. As a result, a large amount of liquid passes through the second orifice passage 13. Therefore, as shown by the solid line in FIG. 12, the dynamic spring constant Kd in the high frequency range can be reduced, and the transmission of minute vibration to the vehicle body can be effectively prevented. In the example shown in FIG. 12, the peak on the high frequency side is tuned to around 200 Hz. However, it is needless to say that this can be changed as appropriate according to the passage sectional area and passage length of the second orifice passage 13. Incidentally, in the above embodiment, the sectional area of the first orifice passage 12 is 7 mm ² ,
The length is set to about 150 mm, the sectional area of the second orifice passage 13 is set to 50 mm ² , and the length is set to about 15 mm. FIG. 10 shows a model of the vibration system of the fluid-filled type vibration damping device in order to help understand the above-mentioned operation. Here, k is the spring constant of the rubber body 3, k
₁ extended spring constant of the first fluid chamber 7, k ₂ represents the expansion spring constant of the second liquid chamber 8 and the third liquid chamber 9. 6 to 9 show different embodiments of the fluid filled type vibration damping device according to the present invention. In this embodiment, the outer cylinder member 2 has an inner collar 4 and an outer collar 18.
, And both are pressed tightly and fixed to each other. A first orifice passage 19 and a second orifice passage 20 are formed in the inner peripheral surface of the outer collar 18. The first orifice passage 19 which communicates the first liquid chamber 7 and the second liquid chamber 8 also has a relatively small passage cross-sectional area (see FIG. 7), and an outer collar 18 for ensuring a long passage length. And is formed at a position where it can be covered by the band-shaped side end 4a of the inner collar 4, as shown in FIG. A bent portion 21 bent in the axial direction of the outer collar 18 is provided at both ends thereof.
, 22 are provided and communicate with the first liquid chamber 7 and the second liquid chamber 8 via the bent portions 21 and 22, respectively. The second orifice passage 20 communicating the first liquid chamber 7 and the third liquid chamber 9 has a window-shaped opening corresponding to the first liquid chamber 7 and the third liquid chamber 9 of the inner collar 4 at one end. As a result, the ends 20a, 2 exposed in the liquid chambers 7, 9 are formed.
Ob communicates with the first liquid chamber 7 and the third liquid chamber 9, respectively. The second orifice passage 20 has a sufficiently large passage cross-sectional area as shown in FIG. In this embodiment, although the groove processing of the first orifice passage 19 and the second orifice passage 20 with respect to the outer collar 18 becomes slightly troublesome, the outer cylinder member 2 has a double structure, and there is an advantage that the number of parts can be reduced. Next, the embodiment shown in FIG. 13 shows an embodiment in which four liquid chambers are defined inside the rubber body 3. That is, the first liquid chamber 24 and the second liquid chamber 25 are formed symmetrically with the substantially vertical partition wall 23 interposed therebetween under the inverted V-shaped main elastic part 3a. At the upper part, a third liquid chamber 26 and a fourth liquid chamber 27 are formed symmetrically. The first liquid chamber 24 serving as the main liquid chamber and the third liquid chamber 26 serving as the sub liquid chamber communicate with each other through a thin and long first orifice passage 28, and the second liquid chamber serving as the main liquid chamber is provided. The chamber 25 and the fourth liquid chamber 27 serving as a sub liquid chamber communicate with each other through a thick and short second orifice passage 29. Therefore, in the above embodiment, one of the vibration systems is constituted by the first liquid chamber 24, the third liquid chamber 26, and the first orifice passage 28, and the second liquid chamber 25, the fourth liquid chamber 27, and the second orifice The other vibration system is constituted by the passage 29. Then, the equivalent mass of the first orifice passage 28 becomes larger than the equivalent mass of the second orifice passage 29. As a result, the vibration system on the side of the first orifice passage 28 resonates in a relatively low frequency range, and the second orifice 28 The vibration system on the side of the passage 29 resonates in a relatively high frequency range. In the case where a large number of liquid chambers are provided as described above, various combinations are possible by changing the communication mode of each liquid chamber. Effects of the Invention As is clear from the above description, according to the fluid filled type vibration damping device according to the present invention,
A sufficiently large loss factor in the low frequency range can be ensured, and the dynamic spring constant in the high frequency range can be suppressed to a small value. Therefore, compared to a conventional vibration isolator tuned to a low frequency range, high frequency vibration can be more effectively cut off, and noise caused by engine vibration can be reduced, for example, as an engine mount. In particular, since the main liquid chamber is arranged on the narrow angle side of the main elastic portion having a substantially V-shape, and the gap is located at a symmetrical position, the volume of the main liquid chamber is surely changed with respect to the input, and the main liquid chamber changes due to vibration of the liquid column. The vibration suppressing action can be obtained more favorably.

【図面の簡単な説明】第１図〜第４図はこの発明に係る流体封入型防振装置の一実施例を示す断面図
であって、第１図は第２図のＩ−Ｉ線に沿った断面図、第２図は第１図のII−II
線に沿った断面図、第３図は第２図のIII−III線に沿った要部のみの断面図、第
４図は第３図のIV−IV線に沿った要部のみの断面図、第５図はこの実施例の分解
斜視図、第６図〜第９図はこの発明の異なる実施例を示す断面図であって、第６
図は第７図のVI−VI線に沿った断面図、第７図は第６図のVII−VII線に沿った断
面図、第８図は第７図のVIII−VIII線に沿った断面図、第９図は第６図のIX−IX
線に沿った要部のみの断面図、第１０図はこの発明の流体封入型防振装置の振動
モデルを示す説明図、第１１図は従来における流体封入型防振装置の周波数特性
図、第１２図はこの発明に係る流体封入型防振装置の周波数特性図、第１３図は
４個の液室を備えた実施例を示す断面図である。１…軸部材、２…外筒部材、３…ゴム体、７…第１液室、８…第２液室、９…
第３液室、１２…第１オリフィス通路、１３…第２オリフィス通路。BRIEF DESCRIPTION OF THE DRAWINGS FIGS. 1 to 4 are cross-sectional views showing an embodiment of a fluid-filled type vibration damping device according to the present invention. FIG. 1 is a sectional view taken along line II of FIG. 2 is a sectional view taken along the line II-II in FIG.
FIG. 3 is a cross-sectional view of only the main part along line III-III in FIG. 2, and FIG. 4 is a cross-sectional view of only the main part along line IV-IV in FIG. FIG. 5 is an exploded perspective view of this embodiment, and FIGS. 6 to 9 are sectional views showing different embodiments of the present invention.
7 is a sectional view taken along the line VI-VI in FIG. 7, FIG. 7 is a sectional view taken along the line VII-VII in FIG. 6, and FIG. 8 is a sectional view taken along the line VIII-VIII in FIG. FIG. 9 is IX-IX of FIG.
10 is an explanatory view showing a vibration model of the fluid filled type vibration damping device of the present invention, FIG. 11 is a frequency characteristic diagram of the conventional fluid filled type vibration damping device, FIG. FIG. 12 is a frequency characteristic diagram of the fluid filled type vibration damping device according to the present invention, and FIG. 13 is a sectional view showing an embodiment having four liquid chambers. DESCRIPTION OF SYMBOLS 1 ... shaft member, 2 ... outer cylinder member, 3 ... rubber body, 7 ... 1st liquid chamber, 8 ... 2nd liquid chamber, 9 ...
Third liquid chamber, 12: first orifice passage, 13: second orifice passage.

Claims

Claims (1) A liquid-filled type vibration damping device in which a rubber member is inserted between a shaft member and an outer cylinder member surrounding the shaft member, wherein the vibration member forms a part of the rubber member, and A pair of main elastic portions extending radially from the shaft member so as to mutually support the shaft member and the outer cylindrical member; and a main elastic member formed inside the rubber body at a narrow angle side of the main elastic portion. A liquid chamber, a gap provided symmetrically with the main liquid chamber with the shaft member interposed therebetween, and a gap penetrating the rubber body in the axial direction, and a position adjacent to the gap inside the rubber body. First and second sub-liquid chambers formed, a first orifice passage formed in the outer cylinder member along a circumferential direction, and communicating the main liquid chamber and the first sub-liquid chamber; The main liquid chamber and the second sub liquid chamber are formed in the outer cylinder member along the circumferential direction, and communicate with the first sub chamber. A second orifice passage having a shorter passage length than the fiss passage and a larger passage cross-sectional area, wherein the first orifice passage is a circumferential one end of the main liquid chamber closer to the first sub liquid chamber. And extends therefrom through the outer peripheral side of the main liquid chamber and the outer peripheral side of the second sub liquid chamber, and the second orifice passage is provided with the second sub liquid chamber of the main liquid chamber. A liquid filling device which is connected to the other end in the circumferential direction which is closer to the main liquid chamber and communicates with the second sub liquid chamber without passing through the outer peripheral side of the first sub liquid chamber. Type anti-vibration device. (2) A liquid-filled type vibration damping device in which a rubber member is inserted between a shaft member and an outer cylindrical member surrounding the shaft member, wherein the vibration member forms a part of the rubber member, and the shaft member and the outer member A pair of main elastic portions extending radially from the shaft member so as to mutually support the cylindrical member, and a pair of main elastic portions, which also form a part of the rubber body, and on a narrow angle side interposed between the pair of main elastic portions. A partition formed at the portion, a pair of main liquid chambers formed respectively between the main elastic portion and the partition inside the rubber body, and the main liquid chamber is symmetrical with the shaft member interposed therebetween. A gap provided at a position and penetrating the rubber body in the axial direction, a pair of sub-liquid chambers formed at a position adjacent to the gap inside the rubber body, one main liquid chamber and one A first orifice passage communicating with the sub liquid chamber, another main liquid chamber communicating with another sub liquid chamber, and And a second orifice passage having a shorter passage length and a larger cross-sectional area than the orifice passage of (1).