US 11,798,771 B2
Adjustable frequency tube resonators
Taehwa Lee, Ann Arbor, MI (US); Hideo Iizuka, Ann Arbor, MI (US); and Ryohei Tsuruta, Ann Arbor, MI (US)
Assigned to Toyota Motor Engineering & Manufacturing North America, Inc., Plano, TX (US)
Filed by Toyota Motor Engineering & Manufacturing North America, Inc., Plano, TX (US)
Filed on Feb. 1, 2021, as Appl. No. 17/163,705.
Prior Publication US 2022/0246382 A1, Aug. 4, 2022
Int. Cl. G10K 11/172 (2006.01); H01J 23/18 (2006.01); H01J 25/58 (2006.01)
CPC H01J 23/18 (2013.01) [G10K 11/172 (2013.01); H01J 25/58 (2013.01)] 20 Claims
OG exemplary drawing
 
1. A variable-frequency, curved tube acoustic resonator comprising:
a side wall forming a tube defining a cylindrical resonance chamber and having an open end configured to receive an incident acoustic wave, and a distal end opposite the open end, the tube defining a curvilinear axis extending along the middle of the resonance chamber from the open end to the distal end, the curvilinear axis having at least one curved region;
a sphere comprising a ferromagnetic material positioned within the tube, defining an end wall, the sphere movable along the curvilinear axis to vary a resonance frequency of the resonator; and
an external magnetic element configured to move and impel a corresponding movement of the sphere.
 
14. A variable-frequency, curved tube acoustic resonator comprising:
a side wall forming a tube defining a cylindrical resonance chamber and having an open end configured to receive an incident acoustic wave, and a distal end opposite the open end, the tube defining a curvilinear axis extending along the middle of the resonance chamber from the open end to the distal end, the curvilinear axis having a helical shape; and
a sphere positioned within the tube, defining an end wall, the sphere movable along the curvilinear axis to vary a resonance frequency of the resonator.