Fluid filled type vibration damping device

A fluid filled type vibration damping device comprising:

• a rubber elastic body elastically connecting a first mounting member and a second mounting member;
• a partition member supported on the second mounting member;
• a pressure receiving chamber whose wall is partly defined by the rubber elastic body;
• an equilibrium chamber whose wall is partly defined by a flexible film;
• the pressure receiving chamber and the equilibrium chamber being filled with a non-compressible fluid, and the pressure receiving chamber and the equilibrium chamber communicating with each other through an orifice passage,
• the partition member that partitions the pressure receiving chamber and the equilibrium chamber being provided with a communication passage that connects the pressure receiving chamber and the equilibrium chamber;
• an obstructing rubber elastic plate being juxtaposed against the communication passage from a pressure receiving chamber side, being adapted to obstruct the communication passage, and being arranged such that pressure of the pressure receiving chamber acts upon a first face of the obstructing rubber elastic plate while pressure of the equilibrium chamber acts on another face thereof;
• and
• a constraining member being provided for retaining an outer peripheral section of the obstructing rubber elastic plate in a state of localized contact against the partition member at multiple locations on a circumference, wherein
• the constraining member provides an opening/closing control member such that positive pressure of the pressure receiving chamber acting on the obstructing rubber elastic plate induces the obstructing rubber elastic plate to push against the partition member and close off the communication passage, whereas negative pressure of the pressure receiving chamber acting on the obstructing rubber elastic plate induces zones situated in an outer peripheral section of the obstructing rubber elastic plate but away from retained sections by the constraining member to undergo elastic deformation in a direction of separation from the partition member, and open up the communication passage, the constraining member is formed such that a plurality of thick retaining portions extending in a circumferential direction are formed at a plurality of locations on the outer peripheral section of the obstructing rubber elastic plate, and the obstructing rubber elastic plate is attached to the partition member with grip portions that are provided on the partition member and that sandwich the thick retaining portions from either side in a thickness direction and retain outside peripheral faces thereof in a state of contact,
• the opening/closing control member comprises elastic deformation zones adapted to undergo elastic deformation on a basis of pressure differential between the pressure receiving chamber and the equilibrium chamber to cause the communication passage to open up, and being defined circumferentially between the thick retaining portions that are adjacently situated in the circumferential direction, and
• open windows that extend further towards the outer peripheral section of the obstructing rubber elastic plate beyond outside peripheral edges of the elastic deformation zones are formed in the partition member in sections thereof that cover a pressure receiving chamber side of the elastic deformation zones.