Patent ID: 7334783
Filing Date: 2008-02-26
Classification: F16F

Abstract:
1. A fluid filled vibration damping device comprising: a first mounting member attachable to one of two members coupled together in a vibration damping manner; a second mounting member attachable to an other of the two members and having a cylindrical portion one opening of which is axially opposed to the first mounting member with a gap therebetween; a rubber elastic body elastically connecting the first and second mounting members so that the rubber elastic body closes off the one opening of the cylindrical portion of the second mounting member with a fluid-tight seal; a flexible layer closing off an other opening of the cylindrical portion with a fluid-tight seal; a partition member disposed within and rigidly supported by the cylindrical portion so that a pressure-receiving chamber having a non-compressible fluid sealed therein and partially defined by the rubber elastic body is formed on one side of the partition member, and an equilibrium chamber having the non-compressible fluid sealed therein and partially defined by the flexible layer is formed on an other side of the partition member; and a low-frequency orifice passage interconnecting the pressure-receiving chamber and the equilibrium chamber, wherein the partition member includes: a first orifice member disposed in a space between the rubber elastic body and the flexible layer and is rigidly supported by the cylindrical portion of the second mounting member at an outer edge thereof, and having a center concavity that opens toward the pressure-receiving chamber; and a second orifice member securely fitted into the center concavity of the first orifice member, wherein the low-frequency orifice passage is formed so as to run circumferentially around an outer circumferential surface of the first orifice member, and ends of the low-frequency orifice passage open directly toward the pressure-receiving chamber and the equilibrium chamber at either axial end surface of the first orifice member, wherein a rubber partition plate is disposed between a bottom wall of the center concavity of the first orifice member and a bottom end surface of the second orifice member to create a seal mechanism that grasps an outer perimeter edge and a center diameter section of the rubber partition plate with a fluid-tight seal between the bottom wall of the center concavity of the first orifice member and the bottom end surface of the second orifice member, wherein semicircular sections of the rubber partition plate surrounded by areas grasped by the seal mechanism constitute a first deformable membrane section and a second deformable membrane section that respectively allow prescribed amounts of elastic deformation along a direction of thickness of the rubber partition plate, such that the first deformable membrane section comprises a first flow restricting assembly disposed in a fluid flow path in a middle-frequency orifice passage and the second deformable membrane section comprises a second flow restricting assembly disposed in a fluid flow path in a high-frequency orifice passage, and wherein a first through-hole that links the first deformable membrane section to the equilibrium chamber and a second through-hole that links the second deformable membrane section to the equilibrium chamber are formed in the first orifice member, and a first through-passage that links the first deformable membrane section to the pressure-receiving chamber and a second through-passage that links the second deformable membrane section to the pressure-receiving chamber are formed in the second orifice member, such that the first through-passage constitutes the middle-frequency orifice passage tuned to a higher range of vibration than the low-frequency orifice passage and the second through-passage constitutes the high-frequency orifice passage tuned to a higher range of vibration than the middle-frequency orifice passage.