Abstract: A valve member formed of an elastomeric membrane for opening and closing a second orifice flow passage is mounted on a partition element such that the valve member is arranged orthogonal to the flow direction of the second orifice flow passage. A valve portion for closing openings of the second orifice flow passage due to flexural deformation of a flexible membrane portion caused by liquid flow in the second orifice flow passage is arranged on the flexible membrane, and communication holes for bring the second orifice flow passage into communication are formed in the flexible membrane portion. A cylindrical buffer portion projecting from the flexible membrane portion for surrounding the openings when the flexible membrane portion is deformed by flexure is provided to the valve portion, and a projection height of the cylindrical buffer portion is set larger than a wall thickness thereof.

Abstract: In a liquid-sealed antivibration device 10 which includes: a main liquid chamber 34A where a vibration-isolating base 16 forms a portion of a chamber wall thereof; a subsidiary liquid chamber 34B where a diaphragm 36 forms a portion of a chamber wall thereof; a partition element 38 by which the main liquid chamber 34A and the subsidiary liquid chamber 34A are partitioned from each other; and an orifice flow passage 40 which allows the main liquid chamber 34A and the subsidiary liquid chamber 34B to be communicated with each other, an elastic membrane 42 is formed on the partition element 38, and the elastic membrane 42 is formed of rubber composition containing butyl rubber or halogenated butyl rubber. Due to such a constitution, an abnormal sound generated by collision of the elastic membrane 42 is reduced.

Abstract: A partition element partitions a liquid-sealed chamber into a main liquid chamber and a first sub liquid chamber. A first orifice flow passage for connecting both liquid chambers is provided. A second diaphragm is formed in the partition element. The partition element includes a second sub liquid chamber partitioned from the main liquid chamber by the second diaphragm and a second orifice flow passage for connecting the first and second sub liquid chambers to each other. A valve portion brought into contact with a periphery around an opening of the second orifice flow passage is formed on a flexible membrane portion of the second diaphragm into a surrounding wall shape. A through hole is formed outside the valve portion, and a projection compressed by a counter wall is formed on a membrane surface of the flexible membrane portion on a main liquid chamber side.

Abstract: A partition element partitions a liquid-sealed chamber into a main liquid chamber and a first sub liquid chamber. A first orifice flow passage for connecting both liquid chambers is provided. A second diaphragm is formed in the partition element. The partition element includes a second sub liquid chamber partitioned from the main liquid chamber by the second diaphragm and a second orifice flow passage for connecting the first and second sub liquid chambers to each other. A valve portion brought into contact with a periphery around an opening of the second orifice flow passage is formed on a flexible membrane portion of the second diaphragm into a surrounding wall shape. A through hole is formed outside the valve portion, and a projection compressed by a counter wall is formed on a membrane surface of the flexible membrane portion on a main liquid chamber side.

Abstract: A valve member formed of an elastomeric membrane for opening and closing a second orifice flow passage is mounted on a partition element such that the valve member is arranged orthogonal to the flow direction of the second orifice flow passage. A valve portion for closing openings of the second orifice flow passage due to flexural deformation of a flexible membrane portion caused by liquid flow in the second orifice flow passage is arranged on the flexible membrane, and communication holes for bring the second orifice flow passage into communication are formed in the flexible membrane portion. A cylindrical buffer portion projecting from the flexible membrane portion for surrounding the openings when the flexible membrane portion is deformed by flexure is provided to the valve portion, and a projection height of the cylindrical buffer portion is set larger than a wall thickness thereof.

Abstract: In a liquid-sealed antivibration device 10 which includes: a main liquid chamber 34A where a vibration-isolating base 16 forms a portion of a chamber wall thereof; a subsidiary liquid chamber 34B where a diaphragm 36 forms a portion of a chamber wall thereof; a partition element 38 by which the main liquid chamber 34A and the subsidiary liquid chamber 34A are partitioned from each other; and an orifice flow passage 40 which allows the main liquid chamber 34A and the subsidiary liquid chamber 34B to be communicated with each other, an elastic membrane 42 is formed on the partition element 38, and the elastic membrane 42 is formed of rubber composition containing butyl rubber or halogenated butyl rubber. Due to such a constitution, an abnormal sound generated by collision of the elastic membrane 42 is reduced.