Vibration-damping device

A vibration-damping device comprising:

• a tubular first attachment member configured to be connected to any one of a vibration generating part and a vibration receiving part, and a second attachment member configured to be connected to the other thereof;
• an elastic body configured to connect the first attachment member and the second attachment member to each other;
• and
• a partition member configured to partition a liquid chamber in the first attachment member into a main liquid chamber having the elastic body as a portion of a barrier wall thereof, and an auxiliary liquid chamber,
• wherein the partition member includes
• a membrane that forms part of the barrier wall of the main liquid chamber and is elastically deformably provided, and
• an orifice that allows the main liquid chamber and the auxiliary liquid chamber to communicate with each other,
• the orifice includes
• a first communication hole that is open toward the main liquid chamber,
• at least one second communication hole that is open toward the auxiliary liquid chamber,
• an intermediate chamber that is located opposite to the main liquid chamber across the membrane and has the membrane as a portion of the barrier wall,
• a restriction passage that extends in a circumferential direction, and
• a communication hole that allows the intermediate chamber and the restriction passage to communicate with each other,
• the restriction passage includes
• a main liquid chamber-side passage that is located on a main liquid chamber side, and
• an auxiliary liquid chamber-side passage that extends from the main liquid chamber-side passage toward an auxiliary liquid chamber side,
• the main liquid chamber-side passage and the auxiliary liquid chamber-side passage extend in the circumferential direction and are disposed to be connected to each other in a radial direction,
• when a liquid flows through the restriction passage from any one of the first communication hole and the at least one second communication hole toward the other, a flow direction in the main liquid chamber-side passage and a flow direction in the auxiliary liquid chamber-side passage are opposite to each other,
• the membrane is provided to be elastically deformed toward the main liquid chamber side and an intermediate chamber side, with an outer peripheral edge portion of the membrane as a fixed end, thereby a whole portion except the outer peripheral edge portion being provided to be elastically deformed toward the main liquid chamber side and the intermediate chamber side,
• a first end portion of the main liquid chamber-side passage in the circumferential direction communicates with the main liquid chamber through the first communication hole,
• a second end portion of the main liquid chamber-side passage in the circumferential direction communicates with the first end portion of the auxiliary liquid chamber-side passage in the circumferential direction through a connection hole,
• the second end portion of the auxiliary liquid chamber-side passage in the circumferential direction communicates with the auxiliary liquid chamber through the at least one second communication hole,
• the partition member includes a partition wall that partitions the intermediate chamber and the auxiliary liquid chamber from each other,
• the at least one second communication hole penetrates the partition wall,
• the at least one second communication hole comprises a plurality of second communication holes, and the plurality of second communication holes are formed in the partition wall, and
• a total sum of respective flow passage cross-sectional areas of the plurality of second communication holes is smaller than a minimum value of a flow passage cross-sectional area of the restriction passage.