Vibration-damping device

1. A vibration-damping device in which at least one of a first liquid chamber and a second liquid chamber has an elastic body as a portion of a wall surface, the vibration-damping device comprising:

a tubular first attachment member joined to one of a vibration generating unit and a vibration receiving unit;

a second attachment member joined to an other of the vibration generating unit and the vibration receiving unit;

an elastic body which joins the first attachment member to the second attachment member; and

a partition member which partitions a liquid chamber in the first attachment member in which a liquid is sealed into a first liquid chamber and a second liquid chamber,

wherein the partition member is provided with a communicating passage through which the first liquid chamber communicates with the second liquid chamber,

the communicating passage is provided with a branching section which branches a flow of the liquid flowing between the first liquid chamber and the second liquid chamber via the communicating passage and a confluence section which joins at least a portion of flows of the liquid which is branched by the branching section to a flow of another portion of the liquid flowing in the communicating passage,

a branching body disposed in the communicating passage is provided as the branching section, and

the branching body is formed as a rigid body with sufficient rigidity that the branching body is not deformed when the branching body receives the flow of the liquid.

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

first confluence sections which join the flows of the liquid which is branched by the branching section to each other is provided as the confluence section.

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

a passage gap through which the liquid passes in a passage axial direction of the communicating passage is provided between an outer circumferential surface of the branching body and an inner circumferential surface of the communicating passage to surround the branching body, and

the first confluence sections protrude from positions of the inner circumferential surface of the communicating passage which are shifted with respect to the branching body in the passage axial direction thereof and change the flows of the liquid which is branched by the branching body and passes through the passage gap inward in a surrounding direction in which the passage gap surrounds the branching body.

4. The vibration-damping device according to claim 2 , wherein

a plurality of branching passages which constitute the communicating passage and are provided independently of each other as the branching section, and

the first confluence sections connect ends of the plurality of branching passages in a passage axial direction as a single body.

5. The vibration-damping device according to claim 1 , wherein

a second confluence section which is provided at the branching section, reverses directions of the flows of the liquid which is branched by the branching section in a flow passage axial direction of the communicating passage, and joins the flows of the liquid to a flow of another portion of the liquid is provided as the confluence section.

6. The vibration-damping device according to claim 5 , wherein

a branching body disposed in the communicating passage is provided as the branching section,

a passage gap through which the liquid passes in a passage axial direction of the communicating passage is provided between an outer circumferential surface of the branching body and an inner circumferential surface of the communicating passage to surround the branching body,

the branching body flows the liquid on the branching body outward in a surrounding direction in which the passage gap surrounds the branching body to branch a flow of the liquid, and

the second confluence section is provided at an end of the branching body of an outside in the surrounding direction and joins a flow of the liquid flowing on the branching body to a flow of the liquid flowing toward the passage gap along an inner circumferential surface of the communicating passage among the liquid flowing in the communicating passage.

7. The vibration-damping device according to claim 1 , wherein

a branching body disposed in the communicating passage is provided as the branching section,

the branching body is disposed on a flow passage axis of the communicating passage.

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

the branching body is provided with a turning section which directs the liquid flowing on the branching body toward an outside in a radial direction of the communicating passage and turns the liquid in a flow passage circumferential direction about the flow passage axis.

9. The vibration-damping device according to claim 1 , wherein

the plurality of communicating passages are provided in the partition member in a circumferential direction of the partition member and pass through the partition member in an axial direction of the partition member.

10. The vibration-damping device according to claim 1 , wherein

the partition member is provided with a restricting passage which is provided independently from the communicating passage and in which the first liquid chamber communicates with the second liquid chamber.

11. The vibration-damping device according to claim 1 , wherein the branching body is integrally formed with the partition member.