Vibration-damping device

1. A vibration-damping device comprising:

a tubular first attachment member that is coupled to any one of a vibration generating part and a vibration receiving part, and a second attachment member that is coupled to the other thereof;

an elastic body that couples the first attachment member and the second attachment member to each other; and

a partition member that partitions a liquid chamber within the first attachment member into a main liquid chamber having the elastic body in a portion of a barrier wall thereof, and an auxiliary liquid chamber,

wherein the partition member includes

a membrane that forms a portion of the barrier wall of the main liquid chamber,

a first orifice passage that is configured to allow the main liquid chamber and an opposite liquid chamber, which is located opposite to the main liquid chamber side with the membrane therebetween and has the membrane as a portion of a barrier wall thereof, to communicate with each other and in which a flow resistance of a liquid in an opposite liquid chamber-side passage located on the opposite liquid chamber side is different from a flow resistance of the liquid in a main liquid chamber-side passage located on the main liquid chamber side,

a damping force difference increasing part that restrains any one of swelling deformation of the membrane toward the main liquid chamber side and swelling deformation of the membrane toward the opposite liquid chamber and increases a difference between a damping force generated when a bound load is input and a damping force generated when a rebound load is input,

wherein the partition member further includes

an intermediate liquid chamber that is the opposite liquid chamber, and

a second orifice passage that is configured to allow the intermediate liquid chamber and the auxiliary liquid chamber to communicate with each other,

wherein the first orifice passage includes the main liquid chamber-side passage, and an intermediate liquid chamber-side passage that is located on the intermediate liquid chamber side as the opposite liquid chamber-side passage,

wherein the damping force difference increasing part includes an uneven swelling part that is formed in the membrane and makes, compared to the swelling deformation of the membrane toward any one liquid chamber side of the main liquid chamber and the intermediate liquid chamber, the swelling deformation of the membrane toward a second liquid chamber side larger when the same pressing force is applied to the membrane, and

wherein the one liquid chamber is located on one passage side with the liquid flow resistance smaller than on a second passage side, out of the main liquid chamber-side passage and the intermediate liquid chamber-side passage, in a flow direction of the liquid in the first orifice passage, and

wherein an other passage having a larger liquid flow resistance than the one passage out of the main liquid chamber-side passage and the intermediate liquid chamber-side passage is a passage having a longer channel length than a channel diameter.

2. The vibration-damping device according to claim 1 ,

wherein the uneven swelling part is curved so as to project toward the one liquid chamber side.

3. The vibration-damping device according to claim 2 ,

wherein the damping force difference increasing part further includes

a sandwiching member that sandwiches an outer peripheral edge of the membrane from both directions of the main liquid chamber side and the intermediate liquid chamber side, and

wherein the uneven swelling part is integrally formed over an entire region of a portion of the membrane located radially inside the outer peripheral edge.

4. The vibration-damping device according to claim 1 ,

wherein the damping force difference increasing part includes a sandwiching member that sandwiches an outer peripheral edge of the membrane from both directions of the main liquid chamber side and the intermediate liquid chamber side,

wherein the sandwiching member includes a first sandwiching part that supports the membrane from one liquid chamber side, which is located on the one passage side in the flow direction of the liquid in the first orifice passage, out of the main liquid chamber and the intermediate liquid chamber, and a second sandwiching part that supports the membrane from the second liquid chamber side located on the second passage side in the flow direction of the liquid in the first orifice passage, and

wherein the first sandwiching part protrudes longer inward in a radial direction than the second sandwiching part.

5. The vibration-damping device according to claim 4 ,

wherein a portion of an inner peripheral edge of the first sandwiching part, which abuts against the membrane, is gradually inclined so as to be spaced away from the second liquid chamber as going inward in the radial direction.

6. The vibration-damping device according to claim 4 ,

wherein the membrane includes an outer peripheral edge that is sandwiched by the sandwiching member, and a body part that is located radially inside the outer peripheral edge and is formed to be thick, and

wherein a gap is provided in the radial direction between an outer peripheral surface of a portion of the body part located closer to the second liquid chamber side than the outer peripheral edge, and an inner peripheral surface of the second sandwiching part.

7. The vibration-damping device according to claim 4 ,

wherein the uneven swelling part is formed in a curved surface shape that projects toward the one liquid chamber side.

8. The vibration-damping device according to claim 7 ,

wherein the uneven swelling part overhangs to an inside of the first sandwiching part.

9. The vibration-damping device according to claim 4 ,

wherein at least one of the first sandwiching part and the outer peripheral edge of the membrane is provided with a plurality of support projections that protrude toward and abuts against an other thereof.