A vehicle wheel includes: a rim including a well portion with an outer circumferential surface, the well portion having a recessed portion formed on the outer circumferential surface; a sub-air chamber member serving as a Helmholtz resonator; and a joining member including a joining portion disposed in the recessed portion. The sub-air chamber member is attached to the outer circumferential surface of the well portion via the joining member.

Provided is a vehicle wheel with which manufacturing costs can be reduced. The vehicle wheel includes a sub air chamber member as a Helmholtz resonator on a well portion of a rim. The sub air chamber member includes a protrusion portion which protrudes toward the rim, and the rim has a hole portion into which the protrusion portion is inserted to engage with the sub air chamber.

Provided is a vehicle wheel with which manufacturing costs can be reduced. The vehicle wheel includes a sub air chamber member as a Helmholtz resonator on a well portion of a rim. The sub air chamber member includes a protrusion portion which protrudes toward the rim, and the rim has a hole portion into which the protrusion portion is inserted to engage with the sub air chamber.

Acoustic impedance matching devices and related methods are disclosed. An acoustic impedance matching device includes a first face for facing an acoustic transducer, a second face opposite the first face, and a lattice structure between the first face and the second face. The second is face curved to at least substantially conformally engage an inner surface of a tubing. An effective acoustic impedance of the lattice structure substantially matches a transducer acoustic impedance of the acoustic transducer to a tubing acoustic impedance of the tubing. A material acoustic impedance of a material of the lattice structure is greater than the effective acoustic impedance. A method of manufacturing an acoustic impedance matching device includes providing, to an additive manufacturing apparatus, a digital design defining the lattice structure, providing an additive manufacturing material to a material intake of the additive manufacturing apparatus, and manufacturing the lattice structure using the additive manufacturing material.

An acoustic metamaterial structure acts as a sound reducing filter in that the level of sound that exits the structure is much less than the magnitude of sound that enters the structure. In forming the structure, modular stages of a given geometry are stacked upon one another to create a cell. Each stage of the cell is provided with a nozzle that is acoustically connected to the nozzles of other stages of the cell. The stages have chambers that are positioned radially or laterally outside of the respective nozzles, with the chambers of the cell being acoustically connected to one another. An amalgamation of cells are arranged in an adjacent formation, with chambers of the cells being acoustically connected to one another for purposes of protecting items, components and people from destructive levels of sound. The geometry of the nozzles and chambers are designed for economical additive manufacture with acoustic infills.

An acoustic-metamaterial acts as a sound reducing filter in that the level of sound that exits the structure is much less than the magnitude of sound that enters the structure. In forming the structure, modular stages of a given geometry are stacked upon one another to create a cell. Each stage of the cell is provided with a nozzle that is acoustically connected to the nozzles of other stages of the cell. The stages have chambers that are positioned radially or laterally outside of the respective nozzles, with the chambers of the cell being acoustically connected to one another. An amalgamation of cells are arranged in an adjacent formation, with chambers of the cells being acoustically connected to one another for purposes of protecting items, components and people from destructive levels of sound.

A muffler comprises a housing enclosed to form a hollow cavity, the cavity comprises a cylindrical chamber and a rectangular parallelepiped chamber, wherein one of bottom surfaces of the cylindrical chamber is connected with a first surface of the rectangular parallelepiped chamber, the cylindrical chamber communicates with an interior of the rectangular parallelepiped chamber, and the cylindrical chamber is provided with an air inlet and an air outlet.

A soundproof structure includes one or more soundproof cells. Each of the one or more soundproof cells includes a frame having a hole portion, a vibratable film fixed to the frame so as to cover the hole portion, and one or more through holes drilled in the film. Both end portions of the hole portion of the frame are not closed, and the frame and the film are formed of the same material and are integrally formed. Therefore, it is possible to provide a soundproof structure and a soundproof structure manufacturing method capable of not only stably insulating sound due to increased resistance to environmental change or aging but also avoiding problems in manufacturing, such as uniform adhesion or bonding of a film to a frame.

A soundproof structure includes one or more soundproof cells. Each of the one or more soundproof cells includes a frame having a hole portion, a vibratable film fixed to the frame so as to cover the hole portion, and one or more through holes drilled in the film. Both end portions of the hole portion of the frame are not closed, and the frame and the film are formed of the same material and are integrally formed. Therefore, it is possible to provide a soundproof structure and a soundproof structure manufacturing method capable of not only stably insulating sound due to increased resistance to environmental change or aging but also avoiding problems in manufacturing, such as uniform adhesion or bonding of a film to a frame.

A noise reduction structure for a ventilation treatment device and the ventilation treatment device are provided. The noise reduction structure comprises a first micropore plate; the first micropore plate has a first plate surface and a second plate surface which are opposite to each other, the first plate surface is used for forming a first chamber; the second plate surface is used for forming an air passage such that air in the air passage flows along the second plate surface; the first micropore plate has a plurality of first micro-vias through which the first chamber communicates with the air passage. The noise reduction structure is wide in noise reduction frequency band, may effectively reduce aerodynamic noise in the air passage, and improves the satisfaction degree of a patient using the ventilation treatment device.