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 sound insulation structure for an internal combustion engine that facilitates the assembly work, and minimizes the transmission vibrations and noises. The sound insulation structure for an internal combustion engine comprises a cover main body (21) disposed outside of a main body (10) of the internal combustion engine and covering at least a part of the engine main body, and a foam sound insulation member (22) made of a foam material and attached to an inner surface (21a) of the cover main body facing the engine main body. The foam sound insulation member covers a noise source (11) of the engine main body and abuts the engine main body or a component part (12, 14) attached to the engine main body at an outer periphery thereof so as to interpose the noise source. The engine main body or the component part includes a sound insulation wall (31-33) projecting therefrom so as to shield a junction part at which the foam sound insulation member abuts or adjoins the engine main body or the component part thereof and the sound insulation wall is covered by the cover main body.

A housing, a vibration assembly, and a vehicle including the vibration assembly is provided, wherein the housing includes a polymer layer and a metal layer. The metal layer is located at an innermost layer of the housing. A material used for the metal layer includes a metal material. The polymer layer is located on an outer side of the metal layer. A material used for the polymer layer includes a polymer material. The housing can convert mechanical vibration energy into heat energy for dissipation, thereby achieving a noise reduction effect.

A fastening device for fastening a shielding part to a partnered fastening part, having: a sleeve with a through opening for a fastener; at least two bridging elements, which are equipped with outer regions in a radial direction for indirect or direct contact with the opposing outsides of the shielding part and are fastened to the sleeve with inner regions in the radial direction; a damping element is positioned between the bridging elements in an axial direction and outside of the sleeve in the radial direction, characterized in that the damping element is embodied as a spring element and has at least one spring arm, which is resiliently flexible in the radial direction and is equipped to cooperate in a supporting way with a hole rim of a hole of the shielding part.

A work machine includes: a partition member provided with an intake port and an exhaust port and forming an engine room; an engine disposed in the engine room; a cooling fan disposed on an intake port side of the engine in the engine room; an exhaust pipe discharging exhaust gas from the engine; and an exhaust duct disposed in the engine room and having an inflow port into which air from the cooling fan flows, and an outflow port. At least a portion of the exhaust duct is disposed above the engine and has a facing surface facing the engine and a through-hole provided in the facing surface. At least a portion of the exhaust pipe is disposed in the through-hole. A gap is formed between an outer surface of the exhaust pipe and an inner surface of the through-hole.

A vibration reduction device having an acoustic meta structure mounted to a vehicle body and configured to block a structure-borne noise transmitted through the vehicle body may include a plurality of unit structures arranged at a predetermined interval therebetween, wherein each of the unit structures includes frame mounted to the vehicle body and configured to separate a predetermined space into a predetermined number of separate sections formed by walls of the frame; and a vibrator formed at a corner portion of each of the separate sections and each of which has a natural frequency to block a vibration transmitted from the vehicle body through the frame.

A vehicle wheel has a Helmholtz resonator (sub-air chamber member) mounted thereon with an adhesive material, and a thickness of the adhesive material on a part (adhesive strength increasing part) of the Helmholtz resonator on which centrifugal force acts strongly during rotation of the wheel is set to be thicker than a thickness of the adhesive material on other parts (regular part) of the Helmholtz resonator. When the thickness of the adhesive material is increased, peel strength of the adhesive material is enhanced accordingly.

A sound-absorbing cover comprises a first sound-absorbing layer and a second sound-absorbing layer made of foam, a first skin layer of the first sound-absorbing layer and a second skin layer of the second sound-absorbing layer are layered in a state of being made to face each other, and an air layer is provided between the facing surfaces of the first skin layer and the second skin layer. The rigidity of the first skin layer of the first sound-absorbing layer is different from the rigidity of the second skin layer of the second sound-absorbing layer.

The present invention relates to a slide-topper anti-flapping and noise silencer device. The anti-flapping device features a folding hinge-like component and a pair of spring clamps. The folding hinge-like component has a pivotally connected rectangular upper panel and rectangular lower panel. The folding hinge-like component is secured along a leading edge of a slide-topper with the upper panel adhered to the top surface of the slide-topper and the lower panel adhered to the bottom surface of the slide-topper. Spring clamps are then used to secure the upper panel and the lower panel to the slide-topper. The anti-flapping device secures and stabilizes the leading edge of the slide-topper to eliminate flapping and any other associated noises.

The present invention aims to provide a sound-absorbing material having sound absorption performance with an average sound absorption coefficient of 0.65 or more in the frequency domain of 800 to 2000 Hz. The present invention relates to a sound-absorbing material including: a fiber layer including a plurality of holes open to a surface thereof and having a thickness of 3 mm or more; and an inorganic material layer formed on the surface of the fiber layer, the holes being blind holes each penetrating through the inorganic material layer and having a bottom inside the fiber layer.