Fluid-filled type vibration-damping device

A fluid-filled type vibration-damping device for elastically connecting two components making up a vibration transmission system in a vibration damping fashion, the device comprising:

• a first mounting member adapted to be attached to one of the two components;
• a second mounting member adapted to be attached to an other one of the two components;
• a main rubber elastic body elastically connecting the first and second mounting members;
• a primary fluid chamber whose wall is partially constituted by the main rubber elastic body having a non-compressible fluid sealed therein;
• an auxiliary fluid chamber whose wall is partially constituted by a flexible film having the non-compressible fluid sealed therein;
• a partition member supported by the second mounting member and positioned such that the primary fluid chamber and the auxiliary fluid chamber are disposed on either side thereof;
• an orifice passage for permitting a fluid communication between the primary and auxiliary fluid chambers;
• and
• an elastic rubber film partially defining the wall of the primary fluid chamber at one of opposite surfaces thereof, and partially defining a pressure action chamber at an other one of opposite surfaces thereof, the elastic rubber film being varied in a rigidity by means of negative pressure acting on the pressure action chamber;
• wherein the elastic rubber film is of generally disk shape and bonded at an outer circumferential surface thereof to a fastener sleeve by vulcanization, the fastener sleeve being fastened to the partition member in order to form the pressure action chamber between the partition member and the elastic rubber film, and
• wherein the elastic rubber film includes a plurality of thick reinforcing ribs that are spaced apart from one another in a circumferential direction and extend in a radial direction from an outside peripheral edge over a length not reaching a center so that areas situated between pairs of adjacent reinforcing ribs in the circumferential direction constitutes thin portions formed by a thin rubber elastic body, while the center portion of the elastic rubber film situated between distal ends of the plurality of reinforcing ribs constitutes a bowed center portion that is thinner than the reinforcing ribs and convex towards a pressure action chamber side.