7results about How to "Effective sound absorption" patented technology

The invention discloses a ventilation-sound insulation integrated ultrathin metasurface grating and a using method thereof. The grating is composed of a perforated cover plate, a bottom plate, a plurality of slender cavities with different lengths formed by separating the perforated cover plate and the bottom plate through wall plates, and a peripheral grid-shaped ventilation area. According to the grille, the excellent broadband sound insulation performance can be achieved on the premise that the high ventilation quantity is guaranteed through a thin layer structure with the thickness as low as about 20 mm. The folded labyrinth resonance sound absorption units with gradient lengths are arranged in the non-ventilation area, broadband continuous sound absorption peaks can be generated, and sound absorption replaces sound insulation, so that broadband sound attenuation performance is obtained. Compared with an existing ventilation and sound insulation grille, the grille structure is thinner, larger in ventilation area and wider in working frequency band, the wide engineering application value of the grille structure is shown, a light-weight and low-frequency broadband noise reduction solution is provided for mechanical equipment such as airplanes, warships, high-speed rails and automobiles, and the mechanical equipment can be widely applied to mechanical equipment such as the airplanes, the warships, the high-speed rails and the automobiles. And the method also has wide application prospects in ventilation and sound insulation systems in green buildings.

The invention discloses a sound absorber based on an Archimedes spiral curled acoustic metamaterial and a preparation method, the sound absorber comprises a sound absorption metamaterial cell element, a sound absorption channel is formed in the sound absorption metamaterial cell element, the sound absorption channel vertically penetrates through the sound absorption metamaterial cell element in the z-axis direction, the sound absorption channel is a spiral channel on the xy two-dimensional section, and the spiral channel is a spiral channel. One end of the spiral channel is opened in the side face of the sound absorption metamaterial cell element, the other end of the spiral channel is a blind end located in the center of the sound absorption metamaterial cell element, and the spiral channel is composed of two Archimedes spiral curves. According to the invention, a brand new sound absorption mechanism is adopted, the problems of strong dispersion and narrow bandwidth which are difficult to solve by a conventional resonance type structure are solved, and effective sound absorption (more than 0.5) of a broadband frequency band (2000Hz) can be realized in a range of 0-6000Hz.

This utility model discloses a polishing mechanism for the production of automotive semi-circular chuck parts, relating to the field of automotive semi-circular chuck part production technology. It includes a placement frame; a buffer base fixed to the lower inner side of the placement frame; a polishing body fixed to the upper end of the buffer base; a lifting mechanism installed and connected to the upper inner side of the placement frame; and a sound-absorbing closing mechanism installed and connected to the lower end of the lifting mechanism, located above the polishing body. When the lifting mechanism extends or retracts, it can change the position of the sound-absorbing closing mechanism to engage and close at the upper end of the polishing body, thereby reducing the noise caused by internal vibrations of the polishing body.

The invention discloses a slit type multi-temperature acoustic metamaterial based on a porous substrate, and particularly relates to the technical field of metamaterials, the metamaterial is a three-dimensional structure formed by combining and arranging a plurality of unit cell structures, and the edge part of the metamaterial is a half unit cell structure; the unit cell structure comprises an inner base body and an outer base body, a slit type perforation channel is formed between the inner base body and the outer base body, and the inner base body and the outer base body are of a unit cell structure. The slit-type multi-temperature acoustic metamaterial based on the multi-scale design of the porous matrix has the advantage of good designability, the geometrical shape and the material of the metamaterial can be customized and designed to a certain extent according to requirements, and the physical geometrical parameters of the metamaterial can be adjusted according to specific requirements, so that the reasonable and excellent sound absorption effect in different temperature environments can be achieved.

The utility model relates to the technical field of bridge and culvert construction, in particular to a convenient-to-assemble sound insulation building board for bridge and culvert construction, and solves the technical problems that during bridge and culvert construction, sound insulation protection needs to be carried out on part of areas, but most of the sound insulation building boards for bridge and culvert construction are complex in assembly step, large in assembly difficulty, and need to consume certain manpower resources. More assembling time is wasted, and the efficient operation of sound insulation building board assembling work is influenced; according to the technical scheme, the convenient-to-assemble sound insulation building board for bridge and culvert construction comprises a sound insulation assembly, an assembling assembly, a telescopic assembly, an adjusting assembly and a limiting assembly; compared with a traditional sound insulation building board which is time-consuming and labor-consuming in assembly operation, tedious in assembly operation steps, difficult to complete installation operation quickly and delayed in construction progress, the sound insulation building board has the advantages that the assembly steps of the sound insulation building board are optimized in an automatic connecting and fixing mode, manpower resources are saved, installation operation time is saved, and construction efficiency is improved. The practical value of the building board is enhanced.

The present invention discloses a low-frequency sound absorption structure and a sound absorption method, comprising a sound absorption unit, wherein the sound absorption unit comprises a base, a cover plate, and an annular nested structure arranged between the base and the cover plate, wherein the annular nested structure comprises a plurality of layers of split resonant cavities from the outside to the inside, and the split resonant cavities are provided with longitudinal openings. The present invention has the advantage of being able to adjust internal components according to the noise spectrum of the actual environment to absorb noises of different frequencies, overcoming the technical bottleneck that the existing acoustic metamaterial cannot change the sound absorption frequency band once printed; the overall structure is compact, the low-frequency sound absorption performance is good, and the sound waves incident at different angles can be absorbed, and the sound absorption and noise reduction of small integrated equipment are suitable.

The invention relates to the technical field of noise reduction for shock absorbers, in particular to a low-noise electromagnetic shock absorber and a noise reduction method. The low-noise electromagnetic shock absorber comprises a push rod, a ball screw nut and a ball screw, the ball screw nut and the ball screw are in threaded engagement, the low-noise electromagnetic shock absorber further comprises a noise reduction cylindrical shell, a center hole is formed in the center of the noise reduction cylindrical shell, and the end, fixedly connected with the ball screw nut, of the push rod is arranged in the center hole in a sliding mode; the noise reduction column shell comprises an inner noise reduction column shell body and an outer noise reduction column shell body, a plurality of counter bores are formed in the outer wall face of the inner noise reduction column shell body and communicated with the center hole through round through holes, grooves corresponding to the counter bores are formed in the inner wall face of the outer noise reduction column shell body, and the grooves and the counter bores form a cavity. And an elastic film layer is arranged between the inner noise reduction cylindrical shell and the outer noise reduction cylindrical shell. Noise can be reduced through the local resonance effect, so that the effects of noise elimination and noise reduction are achieved.