Patent ID: 7216858

Claim:
A fluid-filled vibration damping device for connecting two members in a vibration-damping fashion, comprising: a first mounting member which is to be fixed to one of the two members; a cylindrical second mounting member which is disposed so as to be spaced apart from the first mounting member and which is to be fixed to the other of the two members; an elastic body which is interposed between the first mounting member and the second mounting member for connecting the first mounting member and the second mounting member integrally to each other; a diaphragm whose peripheral portion is retained by the second mounting member so that the diaphragm cooperates with the elastic body to define therebetween a fluid chamber which is filled with a fluid; and a partition structure, which includes an annular metallic partition member and a flexible movable plate disposed in a central opening of the annular metallic partition member, wherein a peripheral portion of the partition structure is retained by the second mounting member, a peripheral portion of the movable plate is fixed to the annular metallic portion member, and the movable plate divides the fluid chamber into a primary fluid chamber and an auxiliary fluid chamber which communicate with each other through an orifice passage, wherein the movable plate has a primary-fluid-chamber-side recess, which consists of a single recess formed in one of opposite surfaces thereof located on the side of the primary fluid chamber and which has a predetermined depth, and an auxiliary-fluid-chamber-side groove, which consists of a single groove formed in the other of the opposite surfaces located on the side of the auxiliary fluid chamber so as to be positioned radially outwardly of the primary-fluid-chamber-side recess and which continuously or discontinuously extends in the circumferential direction, wherein when a positive pressure is generated in the primary fluid chamber, the single auxiliary-fluid-chamber-side groove is deformed such that the groove is collapsed with its space being narrowed, whereby a rigidity of the flexible movable plate is increased, and wherein when a negative pressure is generated in the primary fluid chamber, the single primary-fluid-chamber-side recess is subjected to a compressive shearing deformation, whereby the rigidity of the flexible movable plate is decreased.