Adjustable frequency tube resonators
AssigneeToyota Motor Engineering & Manufacturing North America, Inc.
InventorsTaehwa Lee, Hideo Iizuka, Ryohei Tsuruta
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Abstract
Frequency adjustable quarter-wavelength resonators have a movable end wall defined by a surface of a sphere that is moved within the resonator tube. The sphere can be ferromagnetic, enabling it to be moved by magnetic interactions with moving external magnetic elements, or by a variable external magnetic field, controlled by power modulation to external electromagnets. The resonators can optionally be helical or otherwise curved, and the spherical shape of the structure forming the end wall enables it to navigate curves in the resonator tube.
Claims20
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.
A variable-frequency, 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;
- a sphere, defining an end wall, the sphere comprising a ferromagnetic material, and positioned within the tube, movable along a longitudinal tube axis to vary a resonance frequency of the resonator;
- a first electromagnet positioned adjacent to the open end;
- and
- a second electromagnet positioned adjacent to the distal end,
- wherein power modulation to the first and second electromagnets enables a variable magnetic field to impel the sphere along the longitudinal axis.
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.
Dependencies are inferred from the claim text.