US 12,257,958 B2
Silencing member for electrified vehicle
Shinya Hakuta, Ashigara-kami-gun (JP); Takafumi Hosokawa, Ashigara-kami-gun (JP); and Shogo Yamazoe, Ashigara-kami-gun (JP)
Assigned to FUJIFILM Corporation, Tokyo (JP)
Filed by FUJIFILM Corporation, Tokyo (JP)
Filed on Jul. 9, 2021, as Appl. No. 17/371,639.
Application 17/371,639 is a continuation of application No. PCT/JP2019/049456, filed on Dec. 17, 2019.
Claims priority of application No. 2019-003108 (JP), filed on Jan. 11, 2019.
Prior Publication US 2021/0331630 A1, Oct. 28, 2021
Int. Cl. B60R 13/08 (2006.01); B62D 25/10 (2006.01); G10K 11/172 (2006.01)
CPC B60R 13/0838 (2013.01) [G10K 11/172 (2013.01); B62D 25/10 (2013.01)] 22 Claims
OG exemplary drawing
 
1. A silencing member for an electrified vehicle, the silencing member comprising a film type resonance structure which silences a sound generated from a sound source which is disposed in an electrified vehicle,
wherein the sound source generates a narrow band sound,
the film type resonance structure is disposed in the same space as the sound source or in a vehicle cabin of the electrified vehicle,
the film type resonance structure includes at least one film-like member, a frame which supports the film-like member to allow vibration thereof, and a back plate which is installed in the frame to face the film-like member,
the film-like member, the frame, and the back plate form a back space surrounded by the film-like member, the frame, and the back plate,
the sound generated from the sound source is silenced by film vibration due to the film-like member of the film type resonance structure,
a sound absorption coefficient of film vibration of the film-like member at a frequency in a third or higher order vibration mode is higher than a sound absorption coefficient at a frequency in a fundamental vibration mode,
the sound absorption coefficient is 20% or more over an entire frequency band between adjacent high-order vibration modes, and
a hardness of the film-like member, E×t3 (Pa·m3), is equal to or less than 21.6×d−1.25×Φ4.15,
where:
E represents a Young's modulus of the film-like member;
t represents a thickness of the film-like member,
d represents a thickness of the back space; and
Φ represents a circle equivalent diameter of the region in which the film-like member vibrates.