Vibration damping device
A restricted passageway ( 24 ) is provided with a first communication part ( 26 ) which is formed in a first barrier wall ( 34 ) facing a first liquid chamber and opens to the first liquid chamber, a second communication part ( 27 ) which is formed in a second barrier wall ( 35 ) facing a second liquid chamber and opens to the second liquid chamber, and a main body flow path ( 25 ) that is configured to cause the first communication part ( 26 ) and the second communication part ( 27 ) to communicate with each other. At least one of the first communication part ( 26 ) and the second communication part ( 27 ) includes a plurality of fine holes ( 26 a ) that pass through the first barrier wall ( 34 ) or the second barrier wall ( 35 ). A vortex chamber ( 29 ) is disposed in a connection portion with at least one of the first communication part ( 26 ) and the second communication part ( 27 ) on the main body flow path ( 25 ), figured to form the swirling flow of a liquid depending on a flow velocity of the liquid from the other of the first communication part ( 26 ) and the second communication part ( 27 ), and is configured to cause the liquid to flow out through the fine holes ( 26 a ).
1. A vibration damping device that is a liquid-sealed vibration damping device, comprising:
a first mounting member having a tubular shape coupled to any one of a vibration generating part or a vibration receiving part, and a second mounting member coupled to the other rest of the vibration generating part or the vibration receiving part that is not coupled to the first mounting member;
an elastic body elastically coupling the first and second mounting members; and
a partition member partitioning a liquid chamber that is inside the first mounting member and is sealed with a liquid into a first liquid chamber and a second liquid chamber,
wherein the partition member is formed with a restricted passageway that causes the first liquid chamber and the second liquid chamber to communicate with each other,
the restricted passageway includes a first communication part that is formed in a first barrier wall facing the first liquid chamber and opens to the first liquid chamber, a second communication part that is formed in a second barrier wall facing the second liquid chamber and opens to the second liquid chamber, and a main body flow path that causes the first communication part and the second communication part to communicate with each other,
at least one of the first communication part and the second communication part includes a plurality of fine holes that pass through the first barrier wall or the second barrier wall,
a vortex chamber is disposed in a connection portion of the main body flow path with at least one of the first communication part and the second communication part, forms a swirling flow of the liquid depending on a flow velocity of the liquid from the other of the first communication part and the second communication part, and is configured to cause the liquid to flow out through the fine holes, and
the main body flow path opens from a circumferential direction of the vortex chamber.
2. The vibration damping device according to claim 1 , wherein:
the plurality of fine holes are disposed in the first barrier wall or the second barrier wall in parallel to a swirling direction of the swirling flow of the liquid which is formed in the vortex chamber; and
a ratio of an opening area or a projection area of a minimum cross section in the fine holes occupied per a predetermined area in the first or second barrier wall gradually increases from a rear side to a front side in the swirling direction.
3. The vibration damping device according to claim 1 , wherein:
the main body flow path extends to a circumferential direction of the vibration damping device.
4. The vibration damping device according to claim 1 , wherein:
the plurality of fine holes are formed in the lateral surface of the vortex chamber.