242 results about "Sound energy" patented technology

The invention discloses an earth and rockfill dam material seepage deformation inspection system and method, and relates to the technical field of earth and rockfill dam engineering.The method comprises the steps that a sample of an earth and rockfill dam material is prepared and arranged in a test cavity of a permeameter; maintaining a steady-state seepage field in the sample; in the maintaining process of the steady-state seepage field, acoustic response signals and thermal response signals excited in the sample due to the seepage effect are synchronously collected through a distributed sensing system arranged around the sample; analyzing the acquired acoustic response signal and thermal response signal, and identifying and positioning an acoustic abnormal area with abnormal sound energy release and a thermal abnormal area with abnormal thermal change; and after the early warning signal is generated, the spatial and temporal distribution characteristics of the acoustic abnormal region and the thermal abnormal region are used as input, a parameter distribution field representing the damage evolution of the microstructure in the sample is calculated through a coupled physical inversion algorithm, and the permeability stability of the sample is evaluated based on the parameter distribution field.

The present invention relates to the technical field of sound energy conversion, and disclosed are a sound production apparatus and an electronic device. The sound production apparatus comprises a magnetic circuit system, a first vibration system, a second vibration system, and a housing; the magnetic circuit system is used for forming a first magnetic gap and a second magnetic gap; the first vibration system comprises a first annular diaphragm and a first voice coil, wherein the first voice coil is arranged corresponding to the first magnetic gap; the second vibration system comprises a second diaphragm and a second voice coil; the housing and the first vibration system define a first sound cavity; a side sound outlet hole communicated with the first sound cavity is formed in a side wall of the housing; the housing and the second vibration system define a second sound cavity; and a front sound outlet hole communicated with the second sound cavity is formed in the housing, such that the sound production apparatus can be adapted to a use scenario in which a front sound outlet tube and a side sound outlet tube are provided. Because both the first vibration system and the second vibration system can produce sound, the total radiation area of the sound production apparatus is increased, and the performance of the sound production apparatus is improved.

The invention relates to the technical field of oil sludge resource regeneration, and discloses a water oil sludge resource regeneration device based on a composite ultrasonic field and application. The device comprises an oil sludge parameter acquisition module, a resonant frequency analysis module, a sound field coupling control module, a phase shift interference analysis module and a separation strengthening execution module. The oil sludge parameter acquisition module acquires a rheological characteristic data set of the oil-containing sludge in real time; the resonance frequency analysis module generates a dual-target resonance frequency parameter based on the data set; the sound field coupling control module drives the piezoelectric transducer array to generate a focused ultrasonic field, and a sound field coupling model is constructed; the phase shift interference analysis module corrects the phase offset of the model and outputs a multi-band sound energy injection sequence; and the separation strengthening execution module regulates and controls the rotating speed gradient of the mechanical centrifugal unit, triggers membrane stack pulse backwashing, and finally generates regenerated base oil and a purified water phase product. According to the device, efficient regeneration of water-oil sludge resources is realized through cooperation of multiple modules.

The invention discloses a college dormitory noise multi-dimensional evaluation method based on psychoacoustic and sound field simulation, and belongs to the field of building environment and noise control. The objective of the invention is to solve the problem that an existing dormitory noise evaluation method is single in index and neglects subjective perception and spatial distribution heterogeneity. The method comprises the following steps: acquiring physical data and original audio of dormitory noise through multi-point synchronous acquisition; calculating loudness, sharpness, roughness, fluctuation intensity and comprehensive psychoacoustic annoyance (PA) by using a psychoacoustic model, and scientifically quantifying subjective interference of noise; meanwhile, sound field simulation is carried out based on the accurately established three-dimensional dormitory model, a sound pressure level distribution cloud picture is generated, and a standing wave phenomenon and a sound energy accumulation area are visually revealed; and finally, generating a targeted noise reduction optimization strategy by integrating subjective and objective and spatial analysis results. According to the method, full-chain diagnosis of physical characteristics-subjective perception-spatial distribution of dormitory noise is realized, and a scientific basis is provided for accurate and efficient noise treatment.

The invention relates to the technical field of building materials, in particular to a building sound insulation material based on nano material modification. Comprising the following raw materials in parts by weight: 30-50 parts of matrix resin, 8-15 parts of composite filler, 5-10 parts of a composite foaming agent, 4-8 parts of a curing agent, 3-8 parts of a fiber reinforcement, 3-6 parts of an epoxy toughening agent, 3-6 parts of a coupling agent, 2-5 parts of a plasticizer, 1-4 parts of a flame retardant, 0.5-2 parts of an antioxidant and 0.5-2 parts of a curing accelerator. According to the invention, by solving the problem of agglomeration of nanoparticles, uniform dispersion of carbon nanotubes and nano-silica is realized, the uniformly dispersed carbon nanotubes construct a continuous sound energy conduction dissipation channel by virtue of a high length-diameter ratio, incident sound energy is converted into heat energy through multiple reflections and friction, and the nano-silica cooperates with the composite foaming agent to form a uniform porous structure, so that the sound energy can be converted into heat energy. Sound energy transmission is further blocked, and the sound insulation performance is remarkably improved.

The invention provides a method and system for measuring the sound source radiation sound power level in a reverberation pool, and the method comprises the steps: constructing a reverberation test system according to a preset standard, laying a hydrophone array and a to-be-measured sound source in the reverberation pool, and enabling the array element spacing of the hydrophone array to be smaller than or equal to the minimum half-wavelength; enabling the to-be-detected sound source to emit a to-be-detected signal, and collecting complete time domain sound pressure data of the to-be-detected signal; calculating the mean square sound pressure level of the measuring point in the reverberation control area based on the steady-state time domain sound pressure data of the sound signal; calculating complete time domain sound pressure data of all array elements based on Fourier transform to obtain a sound energy density change curve, and fitting the sound energy density change curve to obtain reverberation time; sound field correction is obtained through calculation according to the reverberation time, and the radiation sound power level of the sound source to be measured is obtained according to the sound field correction. According to the invention, the experiment process is simplified, the measurement efficiency is obviously improved, the experiment cost is reduced, and a new technical approach is provided for the rapid measurement of the water pool of the sound source radiation sound power level.

The invention provides a Helmholtz silencer with broadband sound absorption performance, and belongs to the technical field of silencers. Comprising a tubular neck and a cylindrical back cavity, a plurality of annular thin plates are evenly arranged and fixed on the inner wall of the cylindrical back cavity in the length direction, the distance between every two adjacent annular thin plates is larger than 0 and smaller than 3 mm, and the inner diameters of the annular thin plates are gradually reduced from the tubular neck to the interior of the cylindrical back cavity. A plurality of annular thin plates are fixed in the cylindrical back cavity, so that a gap between two adjacent annular thin plates forms a sound absorption unit, and the inner diameters of the plurality of annular thin plates are gradually reduced from the tubular neck part to the interior of the cylindrical back cavity according to index change; the sound absorption frequency band of the sound absorption device does not completely depend on the inherent frequency generated by resonance of an air column at the neck of the Helmholtz silencer, the structure is simple, the cost is low, the sound energy dissipation when sound waves enter the Helmholtz silencer can be increased, and the sound absorption device has good broadband sound absorption performance.

The utility model relates to a phase change thermo-acoustic engine experimental device which comprises a thermo-acoustic conversion system and an acoustic-electric conversion system. The thermo-acoustic conversion system comprises a sound production module and a Helmholtz resonant cavity, a ceramic plate stack soaked with water exists in the sound production module, and the stable temperature difference needed for generating the thermo-acoustic effect at the two ends of the ceramic plate stack is reduced. Sound waves generated by the thermoacoustic effect form standing waves in the Helmholtz resonant cavity, and the sound intensity is amplified; the acoustic-electric conversion system comprises piezoelectric ceramics and a triode common-emitter amplification circuit, the piezoelectric ceramics are arranged at the tail end of the resonant cavity and convert acoustic energy into electric energy, and the electric energy is amplified by the triode common-emitter amplification circuit and then drives a nixie tube to display. The experimental device integrates thermodynamics, fluid mechanics, acoustics, material science and electronic technology, has the characteristics of simple structure, low cost, rich physical process and strong exploration, is suitable for experimental teaching, particularly suitable for new engineering teaching requirements, and is beneficial to improving the multidisciplinary cross practice ability of students.

The invention discloses an unmanned aerial vehicle precipitation enhancement system and method based on compressed gas sound wave driving, and relates to the technical field of artificial precipitation enhancement, and the method comprises the steps that an unmanned aerial vehicle aircraft provides flight support needed by system high-altitude operation, and supports fixed-height cruise and dual-mode positioning; the high-pressure gas supply module stores compressed gas and provides a continuous and controllable energy source for sound wave generation; the sound wave generation module converts the air pressure energy into sound energy and generates directional low-frequency sound waves, and the directional low-frequency sound waves act on a target cloud area to achieve precipitation enhancement catalysis; the control module is used for unmanned aerial vehicle flight state regulation and control, gas path on-off and pressure adjustment, sound wave frequency closed-loop control, receiving feedback data of all the modules and dynamically adjusting operation parameters through an algorithm. The damping suspension module absorbs counter-acting force generated when sound waves are generated, and interference on the flight attitude of the unmanned aerial vehicle is counteracted. Based on the design, light-weight, low-power-consumption, pollution-free and efficient artificial rainfall enhancement operation can be realized.

The invention relates to the technical field of railway vehicles, and provides a sound absorption device and a railway vehicle. In the sound absorption device, a surrounding plate structure and a flexible film in sealed connection form a closed cavity, at least one through hole is formed in the flexible film, hollow pipes and the through holes are arranged in a one-to-one correspondence mode, one ends of the hollow pipes are inserted into the corresponding through holes, and the other ends of the hollow pipes penetrate through a sound absorption structure and extend to an interval space between the sound absorption structure and a cavity bottom. And a coupling resonance sound absorption system of the flexible film, the hollow pipe, the interval space and the closed cavity is formed. According to the sound absorption device, the sound resistance and the sound quality are improved through the hollow pipe, the resonance frequency is made to move to the low frequency in cooperation with dual coupling resonance of the flexible film and the hollow pipe and dual coupling resonance of the hollow pipe and the cavity, and low-and-medium-frequency noise of 100-500 Hz is efficiently absorbed; the two types of coupling resonance cooperate to broaden the sound absorption frequency band, and the sound absorption structure is attached to the flexible film to enhance the sound energy dissipation efficiency. Efficient low-frequency sound absorption can be achieved without increasing the size, the requirements for light weight and thinness of railway vehicles are met, and the noise control effect is improved.

The invention relates to the technical field of mining machinery intelligent monitoring, and discloses a remote monitoring system and method based on a crusher. According to the system, an original current waveform and a bearing voiceprint signal in a starting stage are collected through an initial state sensing unit, a current waveform deviation spectrum is generated, sound energy of a specific frequency band is extracted, and an initial state data set is formed through fusion; the dynamic operation analysis unit monitors a power fluctuation period, a torque change slope and a material flow noise spectrum in a steady state, and generates a real-time operation state flow; the self-adaptive regulation and control unit identifies an abnormal correlation mode of power and torque, starts fine adjustment of the feeding speed when the torque slope exceeds a threshold, and dynamically adjusts an instruction according to real-time feedback of noise characteristic frequency band energy. According to the scheme, early diagnosis of hidden faults of the equipment and predictive smooth control of the material blocking risk are realized, and the equipment reliability and the production continuity are improved.

The utility model discloses a kind of transcranial ultrasound stimulation devices, it is related to medical instrument and ultrasonic treatment technical field, comprising: ultrasonic transducer;Tightening assembly, it is set to the bottom outside of ultrasonic transducer, and the quick disassembly and installation of ultrasonic transducer are realized by tightening assembly;Ultrasonic coupling assembly, it is set to the bottom of tightening assembly and is matched with ultrasonic transducer, and by ultrasonic coupling assembly, air gap when fitting is reduced to reduce sound energy loss.The utility model is matched by ultrasonic transducer, tightening assembly and ultrasonic coupling assembly, not only can realize accurate ultrasonic wave conduction, can also adapt to complex head shape, especially at complex target point such as binaural area, the flexible characteristic of its soft bag guarantees close fitting with head tissue, so that it can provide consistent sound wave conduction, avoid the interference of air or other material, significantly improve the effect of treatment.

The utility model provides a thermal insulation layer pressurized anti-corrosion chimney, which relates to the technical field of anti-corrosion chimneys and comprises a chimney body, a chimney cap and a chassis, the chimney cap is arranged at the top of the chimney body, the chassis is fixedly connected to the bottom end of the chimney body, an air inlet is arranged on one side of the bottom end of the chimney body, and an air outlet is arranged on the other side of the chimney body. An air supply mechanism is arranged on one side of the air inlet, a noise elimination mechanism is arranged between the air supply mechanism and the air inlet, and the chimney body comprises an outer cylinder, a heat insulation layer and a lining; the fan is communicated with the connecting cover through the ventilation pipe, the connecting cover is installed at one end of the fixing sleeve, the fan conveys air pressure into the fixing sleeve through the ventilation pipe, and the silencing cylinder is clamped into the fixing sleeve through the clamping ring. The sound waves can excite air molecules in countless small holes in the silencing cylinder and the sound absorption sleeve to vibrate, and part of sound energy is consumed to overcome friction force and viscous force, so that silencing is achieved, and noise generated by conveying air pressure is reduced.

This invention discloses a reconstituted bamboo sound barrier and its manufacturing method, relating to the field of sound barrier technology. Specifically, it is a reconstituted bamboo sound barrier comprising spaced, inclined columns, with standard modular screen bodies fixed between the columns by clamping angle steel. The screen body uses a reconstituted bamboo main screen body as the core sound-absorbing body, combined with reconstituted bamboo panels, reconstituted bamboo cavities, reinforcing frames, and other components. The reconstituted bamboo panels have 0.3mm-1.0mm micro-perforations, forming an auxiliary sound-absorbing structure with the sealed reconstituted bamboo cavities, enhancing the sound absorption effect of the reconstituted bamboo main screen body. The diffusion texture of the reconstituted bamboo main screen body disperses reflected sound waves, improving the uniformity of the sound field, allowing more sound energy to "penetrate" into the sound-absorbing material and be consumed. The manufacturing process involves bamboo bundle pretreatment, shaping, and assembly, resulting in a product with low cost, light weight, good durability, environmental friendliness, and excellent acoustic performance, suitable for noise control on highways, railways, and other road sections.

The application discloses a sound production monomer and a sound production module, and relates to the technical field of sound energy conversion. The sound production monomer comprises a magnetic circuit system and a vibration system. The magnetic circuit system is formed with a first magnetic gap and a second magnetic gap which are arranged at intervals along a second direction. The vibration system vibrates along a first direction. The first direction and the second direction are perpendicular to each other. The vibration system comprises a diaphragm, a first voice coil, a second voice coil and a magnetic assembly. The first voice coil is located in the first magnetic gap, and the second voice coil is located in the second magnetic gap. One side of the first voice coil is connected with the diaphragm, and the other side of the first voice coil is connected with the magnetic assembly. One side of the second voice coil is connected with the diaphragm, and the other side of the second voice coil is connected with the magnetic assembly. The current directions of the first voice coil and the second voice coil are the same. The magnetic assembly can provide an acting force opposite to the restoring force direction of the diaphragm for the first voice coil and the second voice coil. The driving force of the first voice coil and the second voice coil on the diaphragm is effectively increased, and the performance of the sound production monomer is improved.

The invention provides a spiral-like sensing assembly and an imaging system thereof, and belongs to the technical field of sensing and detection. The sensing assembly comprises a bottom lining layer and a vibration diaphragm layer, the bottom lining layer is of a spiral-like cavity structure, the vibration diaphragm layer comprises a supporting layer, a plurality of electrode layers and at least one piezoelectric layer, and the positions of the supporting layer, the electrode layers and the piezoelectric layer correspond to each other and are geometrically matched. The plurality of sensing units with different sizes are arranged according to a spiral-like path, and the wave crests and the wave troughs of sensitivity curves are mutually compensated and coupled; the imaging system is composed of a spiral array formed by the sensing assembly, a sound wave emission unit, a central processing module and a display device, and the array further comprises a sound impedance matching layer to improve the sound energy transmission efficiency. The response bandwidth of the sensing assembly is effectively widened, the detection sensitivity and precision of the imaging system are remarkably improved, and the method can be applied to target detection, position calibration and route planning, underwater acoustic communication transmission, fishery breeding monitoring, geological structure exploration and the like; and a certain reference is provided for exploration of light weight and informatization of future equipment.

The invention belongs to the technical field of transformers, and particularly relates to a dry-type transformer which comprises a shell, a sealing door is arranged on one side of the shell, and a transformer body is mounted in the shell; a water storage tank is formed in the shell and used for storing water, and the water is used for reducing noise when the transformer body works; a water inlet groove is formed in the top surface of the shell, and the water inlet groove is communicated with the water storage groove; the water storage tank is filled with water, then the end opening of the water storage tank is sealed by means of the sealing plate, at the moment, when noise generated during working of the transformer body is spread in water, a large amount of sound energy is consumed through friction and viscous effects of sound waves and water molecules, spreading of the sound waves can be greatly hindered, and therefore the noise reduction effect is achieved; and meanwhile, the water can absorb heat generated when the transformer body works, so that the cooling effect is achieved.

The application provides an artificial sound structure lens ultrasonic physiotherapy transducer, an ultrasonic output end of the transducer (2) is fixed at a positioning groove at a bottom end of an artificial sound structure lens, and the ultrasonic output end is closely combined with the artificial sound structure lens; a ring-shaped groove is distributed at an output end of the artificial sound structure lens; epoxy resin (4) is filled in the ring-shaped groove, and the filling height of the epoxy resin is different between different regions of the filling area; the artificial sound structure lens takes the epoxy resin filled in the ring-shaped groove as a phase adjusting medium, adjusts the phase delay of ultrasonic waves by changing the filling height proportion of the phase adjusting medium in the ring-shaped groove, and changes the focal point position of the artificial sound structure lens; and the application can solve the problems of insufficient sound energy of the ultrasonic physiotherapy focal point position, the shallow ultrasonic physiotherapy focal point position, the relatively fixed focal point position of the ultrasonic physiotherapy transducer, and the heating of the contact surface after long-time use.

The invention relates to the technical field of improvement of electroacoustic devices, and discloses a sound guide method for a non-in-ear earphone and a sound guide accessory thereof, and the method comprises the steps: collecting the spatial parameters of the earphone and an ear canal; the optimal gathering angle theta opt is calculated through the sound energy gathering angle optimization model, the sound guide path shape is optimized through the path loss minimization model so as to minimize Lpath, and finally sound guide accessories are manufactured and installed; the fitting comprises an adaptive interface part, an acoustic gathering part and a flexible sound conducting part, directional gathering and efficient conduction of sound energy are accurately controlled through a mathematical model, and on the premise that the non-in-ear earphone is kept painless and comfortable to wear, low-frequency response is remarkably improved, sound leakage is reduced, and sound quality details are improved; the technical contradiction between the poor tone quality of an open earphone and the strong discomfort of an in-ear earphone is effectively solved; the scheme is simple in structure, can be used as a universal accessory or integrally designed, and has wide applicability.

The utility model discloses a kind of surface sound source auxiliary sound systems, including frame, vibrating sound board, driver, sound insulation board and backboard being set to the rear side of the frame;The driver is set on the vibrating sound board, the vibrating sound board and the sound insulation board are set in the frame, the sound insulation board is set between the vibrating sound board and the backboard;First shock absorber is arranged between the vibrating sound board and the frame, second shock absorber is arranged between the sound insulation board and the frame.The surface sound source auxiliary sound system of the utility model passes through reasonable structural design, effectively blocks and absorbs the sound diffused to back, reduces the waste of sound energy, improves the propagation efficiency and directivity of sound, improves tone quality and sound propagation effect.

The application discloses a method for improving focusing efficiency of a ring-shaped ultrasonic transducer array, comprising the following steps: firstly, collecting two groups of echo signals of single emission and multiple reception and self emission and self reception of the ring-shaped ultrasonic transducer array, calculating positions of each transducer element, completing position calibration of the ring-shaped ultrasonic transducer array, and reducing focusing deviation caused by transducer assembly error; and secondly, using the ring-shaped ultrasonic transducer array to perform ultrasonic imaging on a target to be heated, analyzing imaging results, and adjusting transmission delay of the transducer element to reduce focusing deviation caused by uneven medium of the object to be heated. Through the above two steps, the ring-shaped ultrasonic transducer array can maximize the concentration of sound energy on the position to be heated in the focusing process, and the purpose of improving the focusing efficiency of the ring-shaped ultrasonic transducer array is achieved.

The bistable pulse valve with the noise reduction capacity comprises a valve shell, a flushing water flow channel is arranged in the valve shell, and the flushing water flow channel comprises a water inlet channel, a backpressure cavity, a first water outlet channel and a second water outlet channel which are sequentially communicated in the water flow direction, and the first water outlet channel and the second water outlet channel are arranged in parallel. The first pressure relief assembly is connected with the back pressure cavity; a sealing upper cover assembly is fixedly arranged at the top of the valve shell, the sealing upper cover assembly is provided with a pressure relief cavity, and the pressure relief cavity is provided with a first opening communicated with the flushing water flow channel and a second opening communicated with the outside; when the filtering and noise reduction piece blocks the first opening, water flow impacts the inserting part of the filtering and noise reduction piece when flowing from the first water outlet channel to the second water outlet channel, kinetic energy of the water flow is converted into internal energy through the noise reduction holes, sound energy is reduced, and therefore the noise reduction effect is achieved.

The utility model provides an electric control box of a refrigerator and the refrigerator, the electric control box comprises a box body, a cover body and a plurality of mass blocks, the box body forms a containing space with an opening, and the containing space is used for containing an electric control board of the refrigerator; the cover body detachably covers the box body and is used for sealing the opening, and the cover body comprises a mounting wall facing the accommodating space; the plurality of mass blocks are suitable for being connected with the mounting wall and are used for generating resonance under the excitation action of sound waves, and at least two of the plurality of mass blocks have different inherent frequencies. When the electric control board in the box body works and makes noise, the mass block makes contact with sound waves to generate local resonance, so that sound energy radiated outwards by the cover body is reduced, and the noise reduction effect is achieved. In addition, the mass blocks with different inherent frequencies are arranged on the cover body at the same time, the noise elimination frequency band of the electric control box can be widened, and the noise elimination effect of the electric control box is improved.

The application provides an autoclaved aerated concrete board with a fireproof structure, and relates to the technical field of building materials.The autoclaved aerated concrete board comprises a main plate, auxiliary sub-plates fixedly installed on the front end face and the rear end face of the main plate through an adhesive agent, a row of sound-absorbing reflection cavities are evenly arranged in the auxiliary sub-plates, sound waves enter the cavities and are reflected on the cylindrical arc surfaces multiple times, the sound wave energy is attenuated along with the extension of the propagation path due to the divergence and focusing effect of the arc surfaces, the cotton balls made of porous fiber materials cause the sound waves to rub and stick in the fiber pores, the sound energy is converted into heat energy, the sound waves are reflected and attenuated on the cylindrical arc surfaces, the sound waves are absorbed by the cotton balls through the friction of the pores, and the remaining sound waves continue to be reflected and dissipated along the propagation path, so that efficient sound absorption and noise reduction are achieved, and the problem that the autoclaved aerated concrete board cannot form a continuous fireproof barrier at the building joint splicing position and the sound absorption performance cannot meet the noise reduction demand in a high-noise environment is solved.

The invention discloses a vehicle-mounted miniaturized directional strong sound device based on a double-membrane transducer, and the device employs the rear-mounted direct-drive layout of the double-membrane transducer, enables sound waves to directly enter a horn structure, avoids the path loss and energy attenuation caused by the multiple reflection of the sound waves in a conventional reflective structure, and remarkably improves the electroacoustic conversion efficiency. Under the same input power, higher sound pressure level output can be realized, through the synergistic effect of the three-section horn structure with the gradually changing section and the built-in phase cone, the form and the propagation phase of a sound wave wavefront are effectively controlled, sound energy is gradually converged in the propagation process, the sound beam diffusion angle is greatly compressed, the directivity and the propagation distance of sound are enhanced, and the sound quality is improved. In addition, by means of precise integration of the acoustic cavity and vertical installation of the circuit board, high-density layout is achieved in a limited space, and the device is suitable for a vehicle-mounted environment, supports multi-device cascading and matrix deployment, is easy and convenient to install and maintain and has outstanding engineering practicability and reliability.

Provided are a fan with a silencer and a silencer, with which a reduction in silencing performance on the low-frequency side can be suppressed, and the silencer is capable of silencing in a wide band even when a resonance-type silencer is brought close to the fan, which is the sound source.　This fan with a silencer comprises: a fan; and a silencer that silences, by resonance, sound generated by rotation of the fan, the silencer being provided with a wall with an opening, in which a silencer-side opening is provided, and a back space partitioned by the wall with the opening and continuous with the silencer-side opening, the distance between the end of the fan located on the silencer side and the end of the silencer-side opening located on the fan side being the distance at which Fano resonance occurs for the silencer and the sound generated by rotation of the fan, and a conversion mechanism that converts sound energy into thermal energy being provided in at least one of the silencer-side opening and the back space.

This invention relates to the field of bearings, specifically to a noise-reducing bearing with an integrated micro-perforated plate sound-absorbing structure. Rolling elements are disposed between the inner and outer rings of the bearing, and these rolling elements are positioned at intervals by a cage. A sealing ring is disposed on one side of the outer ring. The sealing ring has a mounting structure for installing the micro-perforated plate. The micro-perforated plate is annular and installed at the sealing ring, with a uniform array of micropores. An air cavity is formed between the micro-perforated plate and the sealing ring, constituting the back cavity of the sound-absorbing structure. In this invention, by setting a micro-perforated plate sound-absorbing structure at the bearing's sealing structure, the bearing maintains its original sealing function while possessing active sound absorption capability. When noise generated during bearing operation propagates to the micro-perforated plate, sound waves enter the micropores, generating viscous friction and heat exchange between the air and the pore walls within the micropore channels, thereby converting some of the sound energy into heat energy and dissipating it.

The utility model relates to the technical field of motors, and discloses a mute type permanent magnet fan motor, which structurally comprises a permanent magnet motor, a sealing end cover, a motor seat, a main shaft and a composite shell, and has the beneficial effects that noise can be prevented from leaking from gaps of the motor through a rubber sealing ring arranged at the joint of the sealing end cover and a shell of the permanent magnet motor; and the rotation direction of the plurality of spiral sound absorption blocks on the sound insulation layer on the inner wall of the motor shell is the same as that of the fan impeller in the motor, so that the air flow can be guided to flow orderly when the impeller rotates, the original disordered air flow is adjusted into ordered laminar flow, the wind noise is reduced, and the noise reduction effect of the motor is improved. After sound waves enter the grooves of the spiral sound absorption blocks, the propagation path of the sound waves can be lengthened, the sound waves can be reflected in the spiral grooves for multiple times, sound energy of the sound waves can be absorbed by the sound absorption materials, and therefore noise radiated to the outside can be weakened.