Vibration damping device
A limiting passage ( 24 ) includes: a first communication section ( 26 ) that opens to a first liquid chamber; a second communication section ( 27 ) that opens to a second liquid chamber; and a main body flow passage ( 25 ) that is configured to provide communication between the first and second communication sections. At least one of the first and second communication sections includes a plurality of fine holes ( 31 ). A vortex chamber ( 25 b ) is disposed at a portion of the main body flow passage, which is connected to at least one of the first and second communication sections, is configured to form a swirling flow of liquid according to a flow velocity of liquid flowing from the other of the first and second communication sections, and causes the liquid of the swirling flow to flow out through the plurality of fine holes. A barrier wall ( 36 a ) in which the plurality of fine holes are formed extends in a direction across a vortex axis along a central axis (O 2 ) of the vortex chamber. Among the plurality of fine holes, fine holes located on an inner side in a swirl radial direction across the vortex axis in a top view of the barrier wall have a lower flow resistance than fine holes located on an outer side in the swirl radial direction.
1. A vibration damping device that is a liquid-sealed vibration damping device, comprising:
a first mounting member coupled to either one of a vibration generator and a vibration receiver and having a tubular shape, and a second mounting member coupled to the other of the vibration generator and the vibration receiver;
an elastic body configured to elastically couple the first and second mounting members; and
a partition member configured to partition a liquid chamber, which is inside the first mounting member and in which a liquid is sealed, into a first liquid chamber and a second liquid chamber,
wherein a limiting passage that is configured to provide communication between the first liquid chamber and the second liquid chamber is formed in the partition member,
the limiting passage includes a first communication section that opens to the first liquid chamber, a second communication section that opens to the second liquid chamber, and a main body flow passage that is configured to provide communication between the first communication section and the second communication section,
at least one of the first and second communication sections includes a plurality of fine holes,
a vortex chamber is disposed at a portion of the main body flow passage which is connected to at least one of the first and second communication sections, is configured to form a swirling flow of the liquid according to a flow velocity of the liquid from the other of the first and second communication sections, and to cause the liquid of the swirling flow to flow out through the plurality of fine holes,
a barrier wall in which the plurality of fine holes are formed extends in a direction across a vortex axis along a central axis of the vortex chamber, and
among the plurality of fine holes, fine holes located on an inner side in a swirl radial direction across the vortex axis in a top view of the barrier wall have a lower flow resistance than fine holes located on an outer side in the swirl radial direction.
2. The vibration damping device according to claim 1 , wherein, among the plurality of fine holes, the fine holes located on the inner side in the swirl radial direction have a larger inner diameter than the fine holes located on the outer side in the swirl radial direction.
3. The vibration damping device according to claim 2 , wherein, among the plurality of fine holes, the fine holes located on the inner side in the swirl radial direction have a shorter flow passage length than the fine holes located on the outer side in the swirl radial direction.
4. The vibration damping device according to claim 3 , wherein flow resistances of the plurality of fine holes gradually decrease from the fine holes located on the outer side to the fine holes located on the inner side in the swirl radial direction.
5. The vibration damping device according to claim 2 , wherein flow resistances of the plurality of fine holes gradually decrease from the fine holes located on the outer side to the fine holes located on the inner side in the swirl radial direction.
6. The vibration damping device according to claim 1 , wherein, among the plurality of fine holes, the fine holes located on the inner side in the swirl radial direction have a shorter flow passage length than the fine holes located on the outer side in the swirl radial direction.
7. The vibration damping device according to claim 6 , wherein flow resistances of the plurality of fine holes gradually decrease from the fine holes located on the outer side to the fine holes located on the inner side in the swirl radial direction.
8. The vibration damping device according to claim 1 , wherein flow resistances of the plurality of fine holes gradually decrease from the fine holes located on the outer side to the fine holes located on the inner side in the swirl radial direction.