Fluid-filled vibration damping device

Abstract

In a fluid-filled vibration damping device, a rubber material is injection molded in the upper half of an inner space of a cylindrical insert plate 1 to form a damping rubber member 2 through which an inner tube 3 is retained. A concave 21 is formed in the center of the damping rubber member 2 in such a way that it extends from the periphery to a point close to the inner tube 3 such that both sidewalls thereof are left intact. The concave 21 provides a main fluid compartment A when the insert plate 1 is pressed and fixed in the outer tube. The insert plate 1 has a large concave in the lower half thereof and a plurality of openings are made in the sidewall of the concave 12 except for the bottom wall 121 thereof. A rubber layer 5, injection molded in the concave, has a central part of its width left intact in block form and part of this rubber layer provides a thin rubber wall that covers the openings in the sidewall of the concave 12 which face a cavity 53. When the insert plate 1 is pressed and fixed in the outer tube 4, a sub-fluid compartment B is formed between the outer tube 4 and the thin rubber wall which serves as a defining wall of the compartment B, and this compartment communicates with the main fluid compartment A via a flow constricting channel F around the insert plate 1.