Patent ID: 6648312
Filing Date: 2003-11-18
Classification: F16F

Abstract:
A liquid-sealed antivibration device comprising a cylindrical main body fitting assuming a generally cup shape and having an open top, a boss fitting arranged inboard of the main body fitting in its axial center part, a vibration-isolating base of rubber elastomer interconnecting a lower part of the main body fitting and the boss fitting, a diaphragm of a rubber membrane connected to the main body fitting at its upper extremity so as to cover the open top, an interior room enclosed by the cylindrical main body fitting, the boss fitting, the vibration-isolating base, and the diaphragm and sealed with a liquid, and a partition element arranged between the vibration-isolating base and the diaphragm to compart the interior room into a main liquid chamber on the boss fitting side and a first subsidiary chamber on the diaphragm side, both chambers communicating through an orifice with each other,wherein the partition element includes a partition plate member having an elastic membrane at the central Part of the partition plate member and an orifice member disposed on the first subsidiary chamber side so as to contact with a peripheral edge portion of the elastic membrane in an opposed manner thereto; a first orifice of a generally ring shape is formed by the orifice member, an outer peripheral portion of the partition plate member and a cylindrical rubber portion linking to the diaphragm; a space enclosed by a central plate section of the orifice member and a top surface of the partition plate member is formed as a second subsidiary liquid chamber; the central plate section of the orifice member is formed with a single opening as a second orifice for a muffled sound communicating from the first subsidiary chamber to the second subsidiary chamber, wherein the second orifice is disposed at an eccentric position opposite to an opening of the first orifice, wherein the first orifice is formed in such that a part of its circumferential path enclosed by outer peripheral portions of the partition plate member and the orifice member and the cylindrical rubber portion is closed by a blocking wall portion; the blocking wall portion is formed by a part of the orifice member and a rubber portion adhered by vulcanization to the partition plate member.