FLUID SEALING TYPE VIBRATION ISOLATOR

To provide a fluid sealing type vibration isolator having a novel structure which can tune a switching characteristic or the like for opening and closing a communication port while suppressing an influence to a fluid pressure absorption function of a rubber elastic plate.SOLUTION: In a fluid sealing type vibration isolator 10 in which a communication port 52 for making a pressure receiving chamber 90 and a balance chamber 92 communicate with each other is covered with a rubber elastic plate 66, and a minute pressure variation absorption function is exerted on the basis of an elastic deformation of the rubber elastic plate 66, an external peripheral abutment holding part 72 which is held in a state of being superimposed on a partitioning member 40 is arranged at the rubber elastic plate 66 partially on a circumference, an elastic deformation region 76 for allowing fluid circulation from the balance chamber 92 to the pressure receiving chamber 90 through the communication port 52 by being separated from the partitioning member 40 is arranged between peripheral directions of the external peripheral abutment holding parts 72, 72 of the rubber elastic plate 66, and a radial reinforcing rib 88 extending to an external peripheral side from an internal peripheral abutment holding part 70 which is held in a state of being superimposed on the partitioning member 40 toward the elastic deformation region 76 is protrusively formed at the rubber elastic plate 66.SELECTED DRAWING: Figure 1 【課題】ゴム弾性板の液圧吸収機能への影響を抑えつつ、連通口の開閉の切替特性等をチューニングすることができる、新規な構造の流体封入式防振装置を提供する。【解決手段】受圧室９０と平衡室９２を連通する連通口５２がゴム弾性板６６で覆われており、ゴム弾性板６６の弾性変形に基づいて微小圧力変動吸収機能が発揮される流体封入式防振装置１０において、ゴム弾性板６６には仕切部材４０への重ね合わせ状態に保持される外周当接保持部７２が周上部分的に設けられていると共に、ゴム弾性板６６における外周当接保持部７２，７２の周方向間には、仕切部材４０から離隔することで連通口５２を通じて平衡室９２から受圧室９０への流体流動を許容する弾性変形領域７６が設けられており、ゴム弾性板６６には仕切部材４０への重ね合わせ状態に保持される内周当接保持部７０から弾性変形領域７６に向かって外周側へ延びる放射状補強リブ８８が突出形成されている。【選択図】図１