US 11,869,473 B2
Hollow structure and resonant sound reducing body
Yoshikazu Honji, Hamamatsu (JP); and Azumi Yoshida, Hamamatsu (JP)
Assigned to Yamaha Corporation, Hamamatsu (JP)
Filed by Yamaha Corporation, Hamamatsu (JP)
Filed on Dec. 21, 2020, as Appl. No. 17/128,899.
Application 17/128,899 is a continuation of application No. PCT/JP2019/003368, filed on Jan. 31, 2019.
Prior Publication US 2021/0110807 A1, Apr. 15, 2021
Int. Cl. G10K 11/172 (2006.01); B60C 19/00 (2006.01); B60B 21/12 (2006.01)
CPC G10K 11/172 (2013.01) [B60C 19/002 (2013.01); B60B 21/12 (2013.01)] 13 Claims
OG exemplary drawing
 
1. A hollow structure comprising:
a hollow body with an annular first space; and
at least one resonator in which there is formed an elongated second space with a pair of openings at two ends thereof, each of the pair of openings comprising an opening that opens inwardly toward an interior of the first space, wherein:
a ratio of a length of a centerline of the second space to a length of a centerline of the first space is within a range of from 0.45 to 0.55, and
the second space is disposed in a curve along a circumferential surface of the first space and is shaped such that one of the two ends of the second space is folded back toward the other end.