33results about How to "Anechoic frequency bandwidth" patented technology

The invention provides a high-pressure liquid charging pipeline integrated active silencer. The high-pressure liquid charging pipeline integrated active silencer mainly comprises a cylindrical housing, an actuator arranged in the middle of the housing and based on tubular piezoelectric ceramics, sensors on the inner side of upstream and downstream pipe sections, and a signal pick-up and conditioning system, a power amplifying system and a DSP-based high-speed signal processing system between the housing and the pipe section of the actuator. The high-pressure liquid charging pipeline integrated active silencer is usable for a high-pressure liquid charging pipeline, based on the tubular piezoelectric ceramic-based actuator, and highly integrated. The active pipeline silencer is capable of providing counter noise to counteract the original noise in the pipeline according to the frequency, the size and the phase of the internal flow noise in the pipeline measured in real time, and therefore, the silencer is capable of adapting to the change of the noise frequency, wide in silencing bandwidth and good in silencing effect.

A ventilation and air change sound insulation window is composed of an inner sound insulation window, an outer sound insulation window, a sound absorption structure, air outtake mufflers and air intake mufflers. A window frame of the inner sound insulation window is flush with an internal wall face, a window frame of the outer sound insulation window is arranged on an external wall face, the sound absorption structure is arranged between an upper window frame of the inner sound insulation window and an upper window frame of the outer sound insulation window, the air outtake mufflers are arranged between the upper border of a window hole and the upper window frames, and air intake mufflers are arranged between the lower border of a window hole and lower window frames. Having a wider sound insulation frequency band and greater amount of sound insulation capacity, the mufflers have the advantages of being large in cross-sectional areas of effective sound insulation channels, low in air speed and low in air pressure loss, so that indoor air circulation can be sustained in normal circumstances, and fresh air volume requirements per capita can be met in case of normal population living indoors. The ventilation and air change sound insulation window is compact in structure and convenient to mount.

The invention discloses a broadband multi-cavity resonance-type air intake muffler. The broadband multi-cavity resonance-type air intake muffler comprises a penetrating cylindrical muffler shell, wherein a perforated tube is connected with the interior of the muffler shell in a penetrating manner; an inner cavity is formed between the muffler shell and the perforated tube; a plurality of partition plates are arranged in the inner cavity in the direction perpendicular to the axis; the inner cavity is divided by the partition plates into a plurality of resonant cavities; and a plurality of lines of noise-eliminating through holes which are distributed circumferentially are formed in the perforated tube, and correspondingly positioned at the middles of the resonant cavities. The broadband multi-cavity resonance-type air intake muffler disclosed by the invention is wide in noise-eliminating frequency band, large in noise-eliminating amount, small air intake backpressure, low in engine power loss, small in size, light in weight, simple in structure, convenient to mount, and easy to machine, and has the advantages that engineering is easy to achieve and the application prospect is wide.

The invention provides a multi-cavity direct-through dual-layer perforating silencer capable of eliminating wide-band noise. The multi-cavity direct-through dual-layer perforating silencer capable of eliminating the wide-band noise comprises an inlet end, a silencer body and an outlet end. At least two dual-layer perforating pipes are arranged in the silencer body. The dual-layer perforating pipes are connected in series and separated through partition plates. Each dual-layer perforating pipe comprises an outer pipe body and an inner pipe body, wherein through holes are distributed in the outer pipe body and the inner pipe body, a closed cavity is defined by the outer pipe body, the silencer body and the corresponding partition plate, and another closed cavity is defined by the inner pipe body, the outer pipe body and the corresponding partition plate. The silencer has the advantages that airflow circulates directly from the inlet end to the outlet end, the pressure loss is low, the size is small, the structure is simple, cost is low, and by designing the structure parameters through a multi-cavity one-dimension transfer matrix method, the high-amplitude and wide-band silencing effect can be achieved.

The invention discloses a motor cover for accommodating a motor, which comprises a motor front cover and an air filter hood; wherein the air filter hood comprises a cylindrical meshed exhaust part on which a ventilation hole is formed; an end part of the exhaust part is provided with a fixed baffle and an exhaust hole, and the outside of the end part is fixedly connected with an annular resonant chamber; a cyclone former is arranged between the motor and the motor front cover. The inhaled air stream forms cyclone by arranging the cyclone former between the motor and the motor front cover; wind power is consumed in the cyclone manner and a trace quantity of dust in the wind power is led to the inner side of the resonant chamber, such that the reduction of wind power results in reduction of volume of noise; meanwhile, through holes with different diameters are formed on the inner side surface of the resonant chamber to broaden the effective silence frequency band of the resonant chamber; furthermore, a frequency-lowering groove is arranged in the inner side of the ventilation hole of the meshed exhaust part, so that the divergence of air stream is improved, the air outlet frequency is altered and the voice quality of the vacuum cleaner is greatly improved.

The invention relates to a fan silencer which can be used in inlets, outlets, and ventilation exhaust channels of centrifugal fans, axial flow fans, and fan turbine engines, and can be used in outlets of cooling tower fans; and the fan silencer is excellent in sound attenuation and noise reduction, is large in acoustical absorption coefficient, is wide in noise elimination frequency band, is shock resistant, is small in wind resistance, is high temperature resistant, high pressure resistance, high humidity resistant, and is anti-freeze. The fan silencer is characterized in that a skeleton is properly welded to an inner wall of an outer cylinder; an outer cylindrical sound absorber is assembled and formed by welding and riveting fixation; the center of the outer cylinder is provided with a central cylindrical sound absorber attached to the skeleton; more than two radical radiation sheet type sound absorbers and more than two radical radiation sheet type sound eliminators are arranged between the central cylindrical sound absorber and the outer cylindrical sound absorber, the sheet type sound absorbers and the sheet type sound eliminators are evenly and alternatively arranged, the skeleton at two ends of the sheet type sound absorbers and the sheet type sound eliminators are tightly fixed on a central cylindrical sound absorber skeleton and an outer cylindrical sound absorber skeleton through fasteners, and are fixed and assembled with the central cylindrical sound absorber skeleton and the outer cylindrical sound absorber skeleton through welding and rivets to form a set of product.

The invention relates to an automobile electrical machine heat dissipation fan noise-reduction and anti-vibration system. An electrical machine includes a pedestal, an electrical machine housing which is arranged on the pedestal, a rear cover which is in fixed connection to the electrical machine housing, heat dissipation fins which are evenly disposed on the electrical machine housing, a drive shaft which is disposed inside the electrical machine housing and an electromagnetic coil. An apparatus includes a hydraulic coupler which is in transmission connection to the drive shaft, heat dissipation blades which are evenly disposed in the periphery of a turbine of the hydraulic coupler, an electromagnetic clutch which brings a pump impeller of the hydraulic coupler and the drive shaft into transmission connection, a bypass cooling pipeline which is arranged in the electromagnetic coil, an electromagnetic valve which is disposed in the bypass cooling pipeline, and an ECU controller which is separate and electrical connection to the hydraulic coupler, the electromagnetic coupler and the electromagnetic valve. Compared with prior art, according to the invention, the system herein realizes heat dissipation by combining oil cooling and air cooling, in combination with a micropunch noise elimination structure, can effectively noise of an automobile electrical machine heat dissipation fan and reduce self vibration.

The invention discloses a frequency-adjustable type single-pole multi-frequency resonance muffler. According to the frequency-adjustable type single-pole multi-frequency resonance muffler, a pluralityof noise elimination peak values are in a concerned frequency band, and the noise elimination frequency range can be adjusted. According to the single-pole muffler, a shell part is composed of a fixed shell and a movable shell, and the movable shell can move in a certain range. An even number of pieces of fixed inserting plates and movable inserting plates (above six pieces) are axially insertedin a hollow cavity formed by an exhaust pipe and the two shells, the fixed inserting plates and the movable inserting plates are tightly attached to one another to divide the hollow cavity into an even number (above six) of parallel resonant cavities, a different number of noise elimination holes are formed in the exhaust pipe in the axial direction to form an even number (above six) of parallel resonant cavities, and the number of the cavities is equal to the number of the resonant frequencies. A plurality of coupled holes are formed in the fixed inserting plates, and the fixed inserting plates with the coupled holes and the fixed inserting plates without the coupled holes are arranged at intervals. According to the design, the movable shell can be adjusted to change the range of the noise elimination frequency band. According to the frequency-adjustable type single-pole multi-frequency resonance muffler, a serial-parallel resonant noise elimination structure is constructed in a limited space of the single-pole muffler, and the noise elimination effect is greatly improved.

A draught fan silencer comprises an outer wall, an inner wall, a sound insulation packing material, a supporting base, silencing interlayers, resistance type silencing sheets, lifting rings and reinforcing ribs. The supporting base is arranged at the lower end of the outer wall. The silencing interlayers are connected with the inner wall and internally provided with the resistance type silencing sheets. The lifting rings are arranged at the upper end of the outer wall. The outer wall is made of stainless steel. The sound insulation packing material is arranged between the outer wall and the inner wall. The multiple silencing interlayers are arranged in parallel at equal intervals. The reinforcing ribs are arranged on the outer wall. The draught fan silencer has the beneficial effects that air power noise generated by draught fans of various types is lowered, the silencing amount is large, the silencing band width is high, resistance loss is small, and the structure is simple, installation is convenient; the strength of a shell is enhanced through the reinforcing ribs, the overall strength of the product is enhanced, and the silencer is prevented from being scattered in the transportation or installation process.

The invention relates to a fan sound eliminator which comprises a housing, sound elimination pieces, a sound absorbing material, installing flanges and an interface flange. Two ends of the housing are respectively and fixedly connected with the interface flanges, the sound elimination pieces and the sound absorbing material are located in the housing, the sound elimination pieces are arranged at intervals, two ends of each sound elimination piece are respectively and fixedly connected with the installing flanges, the sound absorbing material is filled in each sound elimination piece, and the installing flanges are fixed to the interface flanges. The fan sound eliminator has the advantages of being simple in structure and convenient to install.

The invention relates to a multi-cavity insert tube type double-layer perforated silencer capable of eliminating broadband noise of a supercharging air intake system. The silencer comprises an inlet end, silencer main bodies and an outlet end. The silencer main bodies are internally provided with at least two double-layer perforated tubes. All the double-layer perforated tubes are connected in series and partitioned through partition plates. Each double-layer perforated tube comprises an outer tube body and an inner tube body which are provided with perforated holes, the outer tube bodies, the corresponding silencer main body and the corresponding partition plate form a closed cavity, the inner tube body extends from the inlet side to the outlet side, and the inner tube body, the corresponding outer tube body and the corresponding partition plate form an unclosed cavity. The silencer is low in pressure loss, compact in structure and low in manufacturing cost, and structural parameters are designed through a multi-cavity one-dimensional transfer matrix method to achieve the high-amplitude broadband silencing effect.

The invention provides a simple foamed aluminum silencer. The simple foamed aluminum silencer comprises a hollow cylindrical housing. A silencer inlet is formed in one end of the cylindrical housing, and a silencer outlet is formed in the other end of the cylindrical housing. A perforated pipe and two foamed aluminum plates are arranged in the cylindrical housing. The foamed aluminum plates are provided with holes and are both perpendicular to the axis of the cylindrical housing. The two foamed aluminum plates are fixed to the inner wall of the cylindrical housing in a sealed mode. The perforated pipe and the cylindrical housing are coaxially arranged. The two ends of the perforated pipe penetrate through the two foamed aluminum plates respectively. Silencing holes are formed in the portion, between the two foamed aluminum plates, of the perforated pipe. The simple foamed aluminum silencer aims to solve the problem that existing silencer materials can cause environment pollution and endanger human health, are prone to moisture absorption and weathering, and are short in service life and poor in effect. The invention belongs to the technical field of silencers.

The invention provides a resonance structure and a silencer comprising the resonance structure, the resonance structure comprises peripheral sealing plates, at least one group of internal side type resonance plates and two side surface resonance plates, and the arrangement direction of the internal side type resonance plates is consistent with the sound propagation direction; the two side surface resonance plates are composed of micropore sound absorption plates, and/or panels, and/or perforated plates. According to the silencer comprising the resonance structure, the low-frequency and high-frequency silencing effects can be greatly improved while it is guaranteed that the intermediate-frequency silencing effect meets the requirement, and the silencing frequency band is widened; a resistive sound absorption material can be filled in the resonance structure as required, so that the high-frequency and medium-frequency noise elimination effects are further improved; in addition, the applicability of different silencing frequencies can be improved by adjusting the internal structure of the resonance structure.

The invention provides a low-noise pneumatic tire tread pattern which comprises a longitudinal groove extending in the circumferential direction of a tire crown and a plurality of resonators connected to one side of the longitudinal groove in parallel at intervals, and each resonator comprises two adjacent narrow grooves. Each narrow groove extends along the surface, far away from the longitudinal groove, of the tire crown to form multiple sections of transverse channels and vertical channels which are connected end to end, the included angle of the transverse channels extending for the first time and deviating from the longitudinal groove direction is A, the vertical channels are distributed in parallel with the longitudinal groove, and the adjacent transverse channels are arranged in parallel; wherein the number of end-to-end connection points of the transverse channel and the vertical channel is at least one. According to the pneumatic tire tread pattern provided by the invention, on one hand, the peak value of a first-order lumen resonance main peak caused by the longitudinal grooves can be well reduced, and on the other hand, the peak values of two secondary split peaks caused by the longitudinal grooves beside the resonators can be effectively reduced. On the other hand, the tread patterns can disperse concentrated tube cavity resonance noise in a wide frequency band, and the purpose of tire noise reduction is well achieved.