Sound acquisition device and range hood

Abstract

The sound collection device comprises a sound collection element and further comprises a shell, a sound transmission channel is defined on the shell and comprises a first channel section and a second channel section which are sequentially connected, the sound collection element is located in the first channel section, and the sound collection element is located in the second channel section. The first channel section is provided with a first sound inlet communicated with the second channel section, the second channel section is provided with a second sound inlet for external sound to enter, and the opening direction of the second sound inlet is upward. The opening direction of the first sound inlet intersects with the extending direction of the main body of the second channel section to form a first included angle, and the first included angle is larger than 0 degree. The oil-proof and wind-proof sound collector has the advantages that the oil-proof and wind-proof purposes can be achieved, noise signals can be fully collected, and then the accuracy of sound collection is guaranteed.

Description

Technical Field

[0001] The present invention relates to the technical field of range hoods, and particularly to a sound collection device and a range hood. Background Art

[0002] A range hood is a kitchen appliance for purifying the kitchen environment. The noise of the range hood has always been one of the main problems troubling users. As a new noise reduction technology, active noise reduction is also considered to be applied to the range hood for noise reduction. The active noise reduction device usually includes a microphone and a speaker, that is, the microphone collects the noise generated when the range hood is working, and the collected noise sound wave is transmitted to the controller in the form of an electrical signal. After being analyzed and processed by the controller, an instruction is sent to the speaker to control the speaker to emit a sound wave matching the noise sound wave to neutralize the noise sound wave, thereby achieving the noise reduction effect. For example, the Chinese invention patent application with the application number CN202010935185.0 (the application publication number: CN111928310A) discloses such a range hood with an active noise reduction function. The microphone of this range hood is arranged in the housing and surrounds the blower in an array distribution manner, and the speaker assembly is distributed below the blower. Another example is the "Range Hood and Its Active Noise Reduction Device" with the application number CN202221822214.3 and the "Low-Noise Range Hood" with the application number CN202222650354.3, which also have similar disclosures.

[0003] To ensure the noise reduction effect, in the prior art, the microphones and speakers used in the active noise reduction system are often arranged inside the air duct of the range hood. However, due to the oily environment of the range hood, the microphones and speakers are often contaminated, resulting in a reduction in the noise reduction effect of the active noise reduction system over time and even malfunction. For this reason, the Chinese utility model patent application with the application number CN201820250745.7 discloses an active noise reduction device for a range hood with an oil prevention device, which includes an incoming device, a central data processor, and a noise reduction unit. The incoming device includes a microphone, which is arbitrarily installed at a place on the range hood. The noise reduction unit includes at least two noise reduction boxes, which are arranged at the bottom of the volute of the range hood, facing the air inlet. An oil prevention device is provided below the noise reduction box, and the oil prevention device is also arranged at the bottom of the volute and covers the noise reduction box. The oil prevention device includes a porous sound-permeable shell and an oil-proof sound-permeable film attached to the surface of the porous sound-permeable shell. At least one noise reduction speaker is arranged in the noise reduction box. Both the microphone and the noise reduction speaker are connected to the central data processor. The central data processor loads a self-check module and an oil pollution detection module for the noise reduction device. The oil pollution detection module detects the oil pollution of the oil prevention device, and the self-check module receives and processes the self-system signals reported by the device to determine whether there is an increase in the microphone and the noise reduction speaker. At the same time, a timing detection module is arranged in the self-check module. However, the oil prevention device of the active noise reduction device in this patent application still has certain deficiencies. The oil prevention device realizes sound transmission and oil prevention through the porous sound-permeable shell and the oil-proof film attached to the surface of the porous sound-permeable shell, without considering the influence of wind noise in the air duct of the range hood, that is, without effective wind noise prevention treatment. On the other hand, for the above-mentioned porous sound-permeable shell, if the number of openings is large, it will have an adverse effect on oil prevention and wind prevention. If the number of openings is small, more noise will be lost during the propagation process, resulting in a reduction in the accuracy of sound collection being affected.

[0004] For another example, a Chinese invention patent application with the application number CN202210185663.X (application publication number: CN114648973A) discloses an active noise reduction device, a range hood, and an active noise reduction method. The active noise reduction device includes a sound signal acquisition device, a processor, a sound signal transmission device, a first housing, and a second housing. The processor is respectively connected to the sound signal acquisition device and the sound signal transmission device. Each housing forms a cavity. The first end of each cavity is open, and the second end of the cavity is closed. The sound signal acquisition device and the sound signal transmission device are respectively located in the corresponding cavities, and the openings of the two cavities are arranged back to back. When the fluid enters any one of the cavities through the opening of any one of the above cavities, an air pressure mass is formed in the any one of the cavities. The air pressure mass located in the cavity cannot continue to be discharged from its closed second end, preventing the subsequent fluid from continuing to flow into the cavity through the cavity opening, achieving the protection of the sound signal acquisition device or the sound signal transmission device in each cavity, and avoiding the pollution and adverse effects of oil fume or water vapor on the devices in the cavity.

[0005] For another example, a Chinese invention patent application with the application number CN202111048335.7 (application publication number: CN113739232A) discloses a protection device, a range hood, and a control method for a range hood. The protection device includes: a connecting pipe adapted to be installed in the housing of the range hood, the connecting pipe having a first end and a second end; a first housing provided at the second end, the first housing being adapted for sound to pass through and not for oil fume to pass through; a second housing provided at the first end, the second housing being adapted to install an active noise reduction device inside, and the second housing is in internal communication with the connecting pipe. The sound generated during the operation of the range hood will pass through the first housing and enter the connecting pipe, and then enter the active noise reduction device. The active noise reduction device operates to reduce noise. The oil fume generated during the operation of the range hood cannot pass through the first housing and cannot pollute the active noise reduction device. [[ID=*]]

[0006] As can be seen from the above, for the protective devices in the prior art, the sound propagation channels formed inside them are divided into two cases: one is like the prior art CN114648973A, where the sound propagation channel does not turn. This form is not conducive to weakening high-frequency sounds, cannot improve the collection accuracy of low-frequency sounds, and the sound collection element is easily contaminated by oil stains. The other is like the prior art CN113739232A, where the sound propagation channel turns, which is conducive to the collection of low-frequency sounds. However, due to two turns, the sound pressure loss on the propagation path is large, affecting the accuracy of sound collection. The sound collection device with multiple turns also makes its volume relatively large, affecting the stability of the air flow at the installation position of the sound collection device. In particular, secondary noise (wind noise) will be generated due to air flow disturbance, further reducing the accuracy of sound collection. Most importantly, the existing sound collection devices basically only perform anti-oil stain treatment and do not consider the impact of wind noise in the air duct of the range hood, that is, they do not perform effective anti-wind noise treatment. In particular, the setting of the connecting pipe in the prior art CN113739232A will occupy a large space in the air duct, and the air flow in the air duct will generate a large amount of wind noise at the connecting pipe. The wind noise will pass through the connecting pipe and enter the position where the microphone is located, causing a great impact on the accuracy of the microphone to collect the target noise. Summary of the Invention

[0007] The first technical problem to be solved by the present invention is, in view of the current situation of the prior art, to provide a sound collection device that can not only achieve the purposes of anti-oil and anti-wind, but also enable the noise signal to be fully collected, thereby ensuring the accuracy of sound collection.

[0008] The second technical problem to be solved by the present invention is, in view of the current situation of the prior art, to provide a range hood applying the above-mentioned sound collection device.

[0009] The technical solution adopted by the present invention to solve the above first technical problem is: The sound collection device includes a sound collection element and also includes a housing. A sound propagation channel is defined on the housing. The sound propagation channel includes a first channel segment and a second channel segment connected in sequence. The sound collection element is located in the first channel segment. The first channel segment has a first sound inlet communicating with the second channel segment. The second channel segment has a second sound inlet for external sounds to enter. The opening direction of the second sound inlet is upward. The opening direction of the first sound inlet intersects with the extension direction of the main body of the second channel segment to form a first included angle, and this first included angle is greater than 0°.

[0010] As an improvement, the above-mentioned sound collection device is arranged in the air duct of the oil fume suction device. The second channel segment is arranged along the extension direction of the air duct, and the second sound inlet is formed at the end of the housing facing away from the wind.

[0011] The above-mentioned "air duct" is understood as any section of the flow path from the air inlet of the smoke collecting hood of the self-priming smoke exhaust device (which can be a range hood or an integrated stove) to the location of the fan system. For example, it can refer to the inner cavity space of the smoke collecting hood, or the space inside the fan frame where the fan system is located, or the channel structure between the fan system and the air outlet of the smoke collecting hood.

[0012] The above-mentioned "the second channel section is arranged along the extension direction of the air duct" can be understood as that the overall extension direction of the second channel section is the same as or parallel to the extension direction of the air duct, or it can also be understood that the overall extension direction of the second channel section has a certain inclination angle relative to the extension direction of the air duct. Considering that a sufficient length of sound propagation channel needs to be set on the sound propagation path for wind noise prevention to reduce the influence of the air flow in the air duct on sound collection, arranging the second channel section in the extension direction of the air duct can make the size of the entire collection device in the direction perpendicular to the extension direction of the air duct smaller, that is, it occupies less space in the air duct of the range hood, and thus makes the air resistance at the location of the collection device in the air duct smaller, so it will not affect the stability of the air flow in the air duct, and at the same time, it also reduces the generation of wind noise to a certain extent. The above-mentioned "the end part of the housing facing away from the wind" can be understood as: along the extension direction of the air duct, the end of the housing adjacent to the fan system.

[0013] In order to avoid an increase in sound pressure loss due to excessive turning during the propagation of sound in the second channel section, the opening direction of the second sound inlet is the same as the extension direction of the main body of the second channel section, that is, the second channel section can be understood as a straight-line channel.

[0014] The housing can be designed with an integral structure, such as a bent pipe structure with an integral design. However, for the convenience of installing components such as sound collection elements, the housing is preferably designed with a split structure assembled by fasteners. Specifically, the housing includes a mounting frame and a wind shield. A receiving groove is formed on the front side wall of the mounting frame, and the sound collection element is placed in the receiving groove. The receiving groove constitutes the first channel section, and the front opening of the receiving groove is the first sound inlet. The wind shield covers the outside of the mounting frame and defines a sound collection channel that is connected to the first sound inlet of the receiving groove and is located in front of the receiving groove between the wind shield and the mounting frame. This sound collection channel constitutes the second channel section.

[0015] The sound collection channel can be a straight channel structure or a non - straight channel structure with local bends or curves. To avoid adverse effects on sound propagation due to excessive turns in the sound propagation path within the sound collection device and to consider the convenience of installing components such as the wind - proof sound - permeable part within the sound collection channel, the extension direction of the main body of the sound collection channel is the same as the extension direction of the air duct. Generally speaking, to minimize the contamination of the sound collection elements on the mounting rack by oil stains, the orientation of the first sound inlet on the mounting rack should be avoided to be the same as the extension direction of the sound collection channel, that is, the opening direction of the first sound inlet and the extension direction of the sound collection channel should be set at an angle. However, the angle formed between the orientation of the first sound inlet and the extension direction of the sound collection channel also needs to be reasonably designed. If the angle formed between the orientation of the first sound inlet and the extension direction of the sound collection channel is too small, the oil fluid will still enter the accommodation groove through the first sound inlet and contaminate the sound collection elements. If the angle formed between the orientation of the first sound inlet and the extension direction of the sound collection channel is too large, the sound propagation path will turn too much, which will have an adverse effect on sound propagation, that is, a part of the sound pressure will be lost, and it is not conducive to the accurate collection of noise by the sound collection elements. Therefore, preferably, the first angle formed by the intersection of the opening direction of the first sound inlet and the extension direction of the main body of the second channel segment is denoted as M, and the value range of M is: 5° ≤ M ≤ 180°. More preferably, considering better avoiding the contact of the sound collection elements with oil stains and improving the wind - proof effect, the main body of the second channel segment extends vertically, and the opening direction of the first sound inlet is horizontally set, that is, the opening direction of the first sound inlet is perpendicular to the extension direction of the main body of the second channel segment; or

[0016] the main body of the second channel segment extends vertically, and the opening direction of the first sound inlet is obliquely upward, that is, the value range of the first angle formed by the intersection of the opening direction of the first sound inlet and the extension direction of the main body of the second channel segment is: 5° ≤ M < 90°; or

[0017] the main body of the second channel segment extends vertically, and the opening direction of the first sound inlet is obliquely downward, that is, the value range of the first angle formed by the intersection of the opening direction of the first sound inlet and the extension direction of the main body of the second channel segment is: 90° < M < 180°; or

[0018] the second channel segment includes a vertically extending segment and a horizontal segment connected to the bottom of the vertically extending segment, and the opening direction of the first sound inlet faces downward and is connected to the horizontal segment.

[0019] The "vertical extension" in the above-mentioned "the main body of the second channel section extends vertically" is not limited to the vertical direction, and can also be inclined at a certain angle (such as 0°-30°) relative to the "vertical direction".

[0020] In a preferred embodiment, the main body of the second channel section extends vertically, the opening direction of the first sound inlet is arranged obliquely upward, and the value range of the first included angle formed by the opening direction of the first sound inlet and the extension direction of the main body of the second channel section is: 30°≤M≤80°. When the first included angle M is in the range of 30°≤M≤80°, it can not only prevent oil stains from flowing down along the side wall of the sound collection channel to contaminate the sound collection element, but also enable the target noise to be smoothly transmitted to the position where the sound collection element is located, that is, to avoid the loss of sound due to too large a turning angle during the transmission of the sound in the second channel section, and not meet the sound pressure requirements for sound collection.

[0021] In another preferred embodiment, the main body of the second channel section extends vertically, the opening direction of the first sound inlet is arranged obliquely downward, and the value range of the first included angle formed by the opening direction of the first sound inlet and the extension direction of the main body of the second channel section is: 100°<M<150°. When the first included angle M is in the range of 100°<M<150°, a better anti-oil stain effect can be achieved to avoid oil stains from contaminating the sound collection element. However, due to too large a turning angle of the sound during the transmission in the second channel section, a certain loss is caused, thus having a certain impact on the accuracy of sound collection.

[0022] As an improvement, the second channel section includes a vertical section arranged successively from top to bottom and an inclined section inclined from the bottom of the vertical section toward the side where the receiving groove is located. The opening of the first sound inlet is communicated with the inclined section of the second channel section. The front wall surface of the mounting frame includes a vertical surface corresponding to the vertical section of the second channel section and an inclined surface corresponding to the inclined section of the second channel section. The vertical surface and the inclined surface intersect to form a second included angle. The vertical surface of the mounting frame and the receiving groove are arranged offset in the up and down direction. The bottom of the vertical surface of the mounting frame also has a hanging edge extending downward.

[0023] Considering that as the turning angle of the sound propagation path increases, certain losses in sound propagation will also increase. Therefore, the turning angle of the second channel section should be minimized as much as possible. Due to the viscosity, surface tension of the oil droplets themselves, and the difference in wall material roughness, the oil droplets are subject to gravity, adhesion force, surface tension, and friction force on the inclined plane. When the inclination angle of the inclined plane is different, the combined action of different forces results in different movement conditions of the oil droplets. For example, when the value of the second included angle N is N ≤ 30°, since the component forces of the adhesion force and friction force resisting gravity in the vertical direction are relatively large, the oil stain will flow down from the vertical surface through the corner and along the inclined surface to reach the sound collection element. Therefore, it is necessary to increase a hanging smoke baffle to prevent the oil liquid from flowing onto the inclined surface. After adding a section of hanging baffle along the corner where the vertical surface and the inclined surface of the mounting frame are joined, the oil droplets will gradually accumulate along the hanging baffle and drip vertically, and will not fall on the sound collection element, thus playing a protective role for the sound collection element.

[0024] To improve the windproof effect of the windproof sound-permeable member, the windproof sound-permeable member extends from the position where the first sound inlet is located to the position where the second sound inlet is located in the sound collection channel. The leeward end of the windproof cover also has an extension wall that extends upward from the position where the second sound inlet is located, and the top edge of this extension wall is higher than the top surface of the windproof sound-permeable member. Affected by the airflow in the air duct, an airflow vortex will be formed at the leeward end of the windproof cover (i.e., at the second sound inlet). The setting of the extension wall of the above-mentioned windproof cover can make the airflow vortex as far away from the second sound inlet as possible, avoiding the influence of the wind noise generated by the airflow vortex on the target noise entering through the second sound inlet.

[0025] To achieve the diversion of the airflow and improve the windproof effect, the windward end of the windproof cover has a diversion surface that gradually inclines towards the inside of the air duct along the direction of the airflow in the air duct. The design of the diversion surface can avoid large airflow disturbances caused by the direct impact of the airflow on the windproof cover, affecting the stability of the airflow.

[0026] Considering that if the inclination angle of the diversion surface towards the inside of the air duct is too large, it will also affect the airflow in the air duct to a certain extent, such as affecting the air volume flowing in the air duct or generating additional noise problems. Therefore, the inclination angle of the diversion surface of the windproof cover needs to be reasonably designed. The mounting frame and the windproof cover are installed on the side wall of the air duct. The included angle formed between the diversion surface of the windproof cover and the side wall of the air duct used to install this windproof cover is denoted as A, and the value range of A is: A ≤ 60°.

[0027] In order to improve the air guiding effect on the air flow, along the air flow direction in the air duct, the position of the guiding surface of the wind shield is upstream of the position of the receiving groove of the mounting bracket. The above structural design also enables there to be sufficient space at the position inside the wind shield opposite to the front part of the receiving groove for arranging components such as the windproof and sound-permeable member and the oil-proof and sound-permeable film.

[0028] In order to wrap and shield components such as the mounting bracket and the windproof and sound-permeable member to achieve the protection purpose, the wind shield includes a first side wall and a second side wall that are opposite to each other left and right and arranged at intervals, and a third side wall connected between the front side edges of the first side wall and the second side wall. The third side wall is opposite to the first sound inlet on the mounting bracket, and the guiding surface is provided at one end of the third side wall facing the wind.

[0029] In a preferred embodiment, it further includes a windproof and sound-permeable member, which is arranged in the second channel section and shields the first sound inlet. After the windproof and sound-permeable member is arranged in the sound collection channel formed between the mounting bracket and the wind shield, wind noise can be effectively eliminated. Even if a small amount of air flow enters the sound collection channel, the pressure pulsation can be weakened in the windproof and sound-permeable member, thereby reducing the influence on the accuracy of the microphone's sound collection. On the other hand, more importantly, considering that the windproof and sound-permeable member is the main windproof component, it should be set to a sufficient length in the sound propagation path to achieve the purpose of effective wind noise prevention, thereby reducing the influence of the air duct air flow on the sound collection. In order to install the windproof and sound-permeable member, choosing to arrange the sound collection channel in the air duct extension direction can make the size of the entire sound collection device in the direction perpendicular to the air duct extension smaller, that is, it occupies less space in the air duct of the range hood, and further makes the wind resistance at the position of the sound collection device in the air duct smaller, so it will not affect the stability of the air flow in the air duct, and at the same time, it also reduces the generation of wind noise to a certain extent.

[0030] Further improvement, the windproof and sound-permeable member is a sound-permeable member made of porous sound-absorbing material. Using a sound-permeable member made of a damping material such as porous sound-absorbing material as the windproof and sound-permeable member can slow down the air flow, eliminate the air flow impact, and also ensure that the sound to be collected can pass through. Specifically, the windproof and sound-permeable member can be made of polyurethane foam, melamine foam sponge, etc. The windproof and sound-permeable member can not only prevent the air flow from impacting the oil-proof and sound-permeable film and generating additional noise, but also the property of its porous material itself can absorb the high-frequency components in the sound energy, realizing the function of filtering the noise signal.

[0031] In order to further improve the oil-proof effect and prevent the sound collection element from being contaminated by oil, an oil-proof and sound-permeable film that shields the front side of the sound collection element is also provided in the receiving groove. There is a fourth distance between the oil-proof and sound-permeable film and the sound collection element, and this fourth distance is denoted as f, where the value range of f is: f≥2mm.

[0032] In order to ensure the oil-proof performance of the oil-proof sound-transmitting film and enable it to effectively transmit sound waves, the oil-proof sound-transmitting film is a polyethylene film.

[0033] In order to avoid the influence of the contact between the oil-proof sound-transmitting film and the wind-proof sound-transmitting member on the sound transmission effect here, the oil-proof sound-transmitting film and the wind-proof sound-transmitting member have a sixth spacing in the front-back direction.

[0034] In order to facilitate the installation of the oil-proof sound-transmitting film, an annular step portion is formed on the side wall of the receiving groove, and the oil-proof sound-transmitting film is disposed on the annular step portion. The four peripheral edges of the oil-proof sound-transmitting film can be fitted and installed on the annular step portion to ensure the sealing performance of the installation of the oil-proof sound-transmitting film.

[0035] While the above-mentioned sound collection device realizes the suppression of wind noise by the sound collection element, it is also necessary to ensure the passage of noise signals. Since the structural design of the sound collection device forms a semi-closed cavity, that is, it itself will form a low-pass filter. Therefore, it is necessary to make the cut-off frequency f of the structure itself c greater than the upper frequency limit f a of the active noise reduction concerned, so as to accurately collect all the original noise frequencies concerned by the active noise reduction. Specifically, the corresponding structural design parameters of the sound collection device must meet the following conditions: the volume of the inner cavity surrounded by the oil-proof sound-transmitting film and the inner wall of the receiving groove is denoted as V, the dimension of the main body of the wind-proof sound-transmitting member in the front-back direction is denoted as e, and the dimension of the wind-proof sound-transmitting member in the up-down direction is denoted as g, where:

[0036] Since there is a large difference in wavelength between high-frequency sound waves and low-frequency sound waves, high-frequency noise can decay rapidly as the propagation distance increases or encounters obstacles. Since the wavelength of low-frequency noise is longer, low-frequency noise is relatively stable during propagation and can penetrate obstacles. Therefore, in the preferred solution, the sound propagation path in the sound collection device adopts a turning design to increase the reflection and scattering of high-frequency sound waves and increase their propagation resistance. For low-frequency sound waves, due to their larger wavelength, they are not affected by the turning of the sound propagation path. Therefore, it is equivalent to adjusting the propagation characteristics of noise in different frequency bands in the channel, thereby achieving the purpose of weakening high-frequency noise and ensuring the propagation of low-frequency noise. To attenuate high-frequency noise above frequency f0, the sound propagation path within the sound collection device is divided into three regions. The horizontal plane passing through the upper edge of the first sound inlet is designated as a first reference plane k1, the horizontal plane passing through the lower edge of the second sound inlet is designated as a second reference plane k2, the vertical plane at the first sound inlet is designated as a third reference plane k3, the horizontal plane at the second sound inlet is designated as a fourth reference plane k4, and the vertical plane passing through the location of the sound collection element is designated as a fifth reference plane. The area of the region between the first and fourth reference planes on a vertical cross-section of the second channel segment taken along the front-to-back direction is designated as S. 01 The area between the first reference plane and the second reference plane is denoted as S 02 The area between the third reference plane and the fifth reference plane on the vertical cross section of the receiving groove cut along the front-to-back direction is recorded as S 03 , where the values of the above areas meet the conditions:

[0037]

[0038] The size of the first sound inlet in the vertical direction is denoted as m, the size of the second sound inlet in the horizontal direction is denoted as d1, and the size of the second sound inlet in the front-back direction is denoted as e. The above three satisfy the following conditions:

[0039]

[0040] Among them, f0 is the lowest noise frequency of the high-frequency noise that needs to be weakened, and v is the speed of sound propagation.

[0041] The technical solution adopted by the present invention to solve the second technical problem is: a range hood, including an air duct for smoke to pass through and a sound collection device arranged in the air duct, wherein the sound collection device adopts the above-mentioned sound collection device.

[0042] As an improvement, the sound collecting element is a microphone.

[0043] Compared with the prior art, the advantages of the present invention are as follows: The sound collection element is placed in the first channel section of the housing, which can effectively isolate the interference of the air flow in the air duct on the sound collection element and prevent the oil stain in the air flow from contaminating the sound collection element. The opening direction of the first sound inlet is set to intersect with the extending direction of the second channel section of the housing to form a first included angle, and the first included angle is greater than 0°. This can make the whole path for the external noise to enter the second channel section from the second sound inlet and then propagate to the position of the sound collection element in the first channel section a turning path. This turning path can avoid too much oil stain directly passing through the second channel section and contacting the sound collection element, but make most of the oil stain adhere to the side wall of the second channel section, so that the sound collection element can be as far away from the oil stain as possible and the service life of the sound collection element can be extended. On the other hand, the sound propagation path in the collection device adopts a turning path design, which has a weakening effect on high-frequency sounds (such as the high-frequency sound components in wind noise and the high-frequency sound components generated by the fan system and other non-target noises), and has little influence on low-frequency sounds. Therefore, it can be better applied to the propagation of low-frequency noises in the sound collection device, which is conducive to the accurate collection of the sound collection element. Considering the installation environment of the sound collection device (usually located below the fan system), the second sound inlet is set upward, so that the external noise can smoothly enter the second channel section from top to bottom through the second sound inlet, avoiding the loss of sound pressure due to too many turns in the sound propagation path and ensuring the accuracy of sound collection. Description of the Drawings

[0044] Figure 1 Schematic perspective view of the sound collection device according to Embodiment 1 of the present invention;

[0045] Figure 2 Exploded view of the sound collection device according to Embodiment 1 of the present invention;

[0046] Figure 3 Vertical sectional view of the sound collection device according to Embodiment 1 of the present invention;

[0047] Figure 4 For Figure 3 Schematic structural view after removing the windproof sound-permeable member in;

[0048] Figure 5 For along Figure 3 Cross-sectional view taken along the A-A direction in;

[0049] Figure 6 Schematic perspective view of the sound collection device according to Embodiment 1 of the present invention installed in the air duct;

[0050] Figure 7 For Figure 6 Cross-sectional view taken along the front-back direction;

[0051] Figure 8 Schematic diagram of the sound propagation process at the first sound inlet of the mounting bracket

[0052] Figure 9 Vertical sectional view of the sound collection device according to Embodiment 2 of the present invention

[0053] Figure 10 For Figure 9 Schematic diagram of the structure after removing the windproof sound-permeable member in

[0054] Figure 11 Vertical sectional view of the sound collection device according to Embodiment 3 of the present invention (the mounting bracket does not have a hanging edge)

[0055] Figure 12 For Figure 11 Schematic diagram of the structure after removing the windproof sound-permeable member in

[0056] Figure 13 Vertical sectional view of another structure of the sound collection device according to Embodiment 3 of the present invention (the mounting bracket has a hanging edge)

[0057] Figure 14 For Figure 13 Schematic diagram of the structure after removing the windproof sound-permeable member in

[0058] Figure 15 Vertical sectional view of the sound collection device according to Embodiment 4 of the present invention

[0059] Figure 16 For Figure 15 Schematic diagram of the structure after removing the windproof sound-permeable member in

[0060] Figure 17 Vertical sectional view of the sound collection device according to Embodiment 5 of the present invention

[0061] Figure 18 For Figure 17 Schematic diagram of the structure after removing the windproof sound-permeable member in Detailed implementation manners

[0062] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments.

[0063] In the description and claims of the present invention, directional terms such as "front", "rear", "upper", "lower", "left", "right", "side", "top", "bottom", etc. are used to describe various exemplary structural parts and elements of the present invention. However, these terms are used here only for the purpose of convenience of description and are determined based on the exemplary orientations shown in the drawings. Since the embodiments disclosed in the present invention can be arranged in different directions, these directional terms are used only for illustration and should not be regarded as limitations. For example, "upper" and "lower" are not necessarily limited to the directions opposite to or consistent with the direction of gravity.

[0064] Embodiment 1

[0065] Figures 1 - 7 A preferred embodiment of the sound collection device and the range hood of the present invention is shown.

[0066] The sound collection device includes a sound collection element 11 and a housing 2. A sound propagation channel is defined on the housing 2. Among them, the sound propagation channel includes a first channel segment and a second channel segment connected in sequence. Among them, the sound collection element 11 is located in the first channel segment. The first channel segment has a first sound inlet 211 communicating with the second channel segment. The second channel segment has a second sound inlet 45 for external sound to enter therein. The extension line of the opening direction of the first sound inlet 211 intersects with the extension line of the opening direction of the second sound inlet 45. In a preferred embodiment, both the first channel segment and the second channel segment are straight-line channels. Among them, the extension line of the first channel segment intersects with the extension line of the second channel segment. The extension line of the first channel segment can be understood as the connection line between the position where the sound inlet of this channel segment is located and the position where the sound collection element 11 is located. The extension line of the second channel segment can be understood as the connection line between the position where the sound inlet of this channel segment is located and the position where the sound outlet is located.

[0067] The active noise reduction system is usually arranged in the air duct 10 of an oil fume suction device (such as a range hood or an integrated stove with an oil fume suction function, etc., which are kitchen appliances), and the sound collection device is an important part of the active noise reduction system and is also correspondingly arranged in the air duct 10 of the oil fume suction device. Taking a range hood as an example, the above-mentioned "air duct" can refer to the housing of the range hood or a box structure with a "channel" for the oil fume to pass through alone, such as the channel between the fan system and the smoke collecting hood of a ceiling-mounted range hood. The active noise reduction system generally includes a sound collection element 11 (microphone) and a speaker, that is, the microphone collects the noise generated when the range hood is working, and the collected noise sound wave is transmitted to the controller in the form of an electrical signal. After being analyzed and processed by the controller, an instruction is sent to the speaker to control the speaker to emit a sound wave matching the noise sound wave to neutralize the noise sound wave, thereby achieving the noise reduction effect. The sound collection device of this embodiment can be used to install the above-mentioned sound collection element 11 and provide protection against oil and wind.

[0068] The sound collection device is located below the fan system, that is, the noise generated by the fan system propagates downward along the air duct 10, and the sound collection device is exactly arranged on the downward propagation path in the air duct 10. In addition to the housing, the sound collection device also includes an oil-proof sound-permeable membrane 28 and a wind-proof sound-permeable member 30. The housing includes a mounting bracket 20 and a wind-proof cover 40.

[0069] In this embodiment, taking the box body 1 with a "channel" for the oil fume to pass through alone as an example, the installation structure of the sound collection device is described, and the channel in the box body 1 serves as the air duct 10. The mounting bracket 20 can be installed on the rear side wall of the air duct 10, and a receiving groove 21 for placing the sound collection element 11 is formed on its front side wall, and this receiving groove constitutes the first channel section of the above-mentioned housing 2. The front part of the receiving groove 21 has an opening as the first sound inlet 211 for the sound to enter the receiving groove 21. Among them, the first sound inlet 211 should be understood as an opening for the sound from the outside (the second channel section in this embodiment) to enter the receiving groove 21 and be effectively collected by the sound collection element, such as Figure 8 the opening defined by the boundary points such as A1 and A2 of the receiving groove 21 in the circumferential direction, and it does not necessarily refer to the largest opening at the front part of the receiving groove 21. In the state where the mounting bracket 20 is installed in place on the rear side wall of the air duct 10, the rear wall of the part of the mounting bracket 20 where the receiving groove 21 is located is attached to the rear side wall of the air duct 10. In order to improve the accuracy of sound collection of the active noise reduction system, generally two or more sound collection elements 11 are arranged, and for this reason, components such as the mounting bracket 20, the wind-proof sound-permeable member 30, and the wind-proof cover 40 are also correspondingly provided with two or more.

[0070] The mounting bracket 20 further has a third mounting portion 263 extending respectively to the left and right sides and exposing outside the wind shield 40, and a fourth mounting portion 264 extending downward at the bottom of the mounting bracket 20 and exposing outside the wind shield 40. Both the third mounting portion 263 and the fourth mounting portion 264 are connected to the side wall of the air duct 10 by screws. In the lower region of the receiving groove 21 of the mounting bracket 20, there is a connecting post 265 extending forward, and the wind shield 40 can be connected to the connecting post 265 of the mounting bracket 20 by screws 50.

[0071] The wind shield 40 includes a first side wall 411 and a second side wall 412 that are opposite to each other left and right and arranged at intervals, and a third side wall 413 connected between the front side edges of the first side wall 411 and the second side wall 412. The third side wall 413 of the wind shield 40 is located at the front side of the receiving groove 21 of the mounting bracket 20. On the third side wall 413 of the wind shield 40, there is a guiding surface 4130 that gradually inclines towards the inside of the air duct 10 along the airflow direction in the air duct 10 (as shown by the hollow arrow in Figure 3 ). Specifically, the guiding surface 4130 is located at the lower part of the third side wall 413, that is, at the windward end of the third side wall 413, and it inclines forward from bottom to top, while the upper part of the third side wall 413 is basically vertically extended and is opposite to the part where the receiving groove 21 of the mounting bracket 20 is located in the front-rear direction. Along the airflow direction in the air duct 10, the position where the guiding surface 4130 of the wind shield 40 is located is upstream of the position where the receiving groove 21 of the mounting bracket 20 is located. Arranging the guiding surface 4130 of the wind shield 40 at a lower position also makes there be enough space to arrange components such as the wind-proof sound-transmitting member 30 and the oil-proof sound-transmitting film 28 at the position in the wind shield 40 opposite to the front part of the receiving groove 21. In addition, considering that if the inclination angle of the guiding surface 4130 towards the inside of the air duct 10 is too large, it will also affect the airflow in the air duct 10 to a certain extent, such as affecting the air volume flowing in the air duct 10 or generating additional noise problems. Therefore, the inclination angle of the guiding surface 4130 of the wind shield 40 needs to be reasonably designed. The included angle formed between the guiding surface 4130 of the wind shield 40 and the side wall of the air duct 10 for mounting the wind shield 40 is denoted as A, and the value range of A is: A ≤ 60°. In order to reduce the influence of the installation of the sound collection device on the flow field in the air duct 10, the dimension of the air duct 10 in the front-rear direction in this embodiment is denoted as a, and the distance that the wind shield 40 protrudes forward relative to the side wall of the air duct 10 for mounting the wind shield 40 is denoted as b. Considering that if the distance that the wind shield 40 protrudes forward is too large, such as b / a > 0.35, on the one hand, it will affect the air volume flowing in the air duct 10, and on the other hand, it will also cause a turbulence problem of the airflow at the position of the sound collection device in the air duct 10, generating additional noise and affecting the accuracy of sound collection. Therefore, the value of b / a needs to be reasonably limited. In this embodiment, preferably, b / a ≤ 0.35, as detailed in Figure 7 .

[0072] To improve the anti-oil pollution effect, the wind shield 40 of this embodiment can be made of plastic or metal parts.

[0073] A gap channel extending vertically in the front-rear direction is formed between the front side surface of the wind shield 40 and the mounting frame 20 of this embodiment. The upper end (i.e., the end close to the noise source) of the gap channel is open, and the lower end (i.e., the end far from the noise source) is closed, which is the sound collection channel 200. The sound collection channel 200 is located on the front side of the mounting frame 20, that is, it constitutes the second channel section of the above-mentioned housing 2. More specifically, a second sound inlet 45 communicating with the above-mentioned sound collection channel 200 is defined between the windward end portion of the wind shield 40 (i.e., a section along the extension direction of the air duct, close to the fan system of the range hood) and the front side wall of the mounting frame 20. The air duct 10 and the sound collection channel 200 of this embodiment both extend vertically, that is, the extension direction of the sound collection channel 200 is the same as the extension direction B2 of the air duct 10. The opening direction of the above-mentioned second sound inlet 45 is upward. The opening direction B1 of the first sound inlet 211 intersects with the extension direction B3 of the sound collection channel 200 to form a first angle. Considering that if the angle formed between the orientation B1 of the first sound inlet 211 and the extension direction B3 of the sound collection channel 200 is too small, the oil liquid will still enter the accommodation groove 21 through the first sound inlet 211 to pollute the sound collection element 11. If the angle formed between the orientation B1 of the first sound inlet 211 and the extension direction B3 of the sound collection channel 200 is too large, the sound propagation path turns too much, which will have an adverse effect on sound propagation, that is, a part of the sound pressure will be lost, which is not conducive to the accurate collection of noise by the sound collection element. Therefore, the angle formed between the orientation of the first sound inlet 211 and the extension direction B3 of the sound collection channel 200 also needs to be reasonably designed. The value range of this first angle is: 0° < M < 180°. More preferably, the value of the first angle in this embodiment is 90°, that is, the opening direction B1 of the first sound inlet 211 is perpendicular to the extension direction B3 of the sound collection channel 200.

[0074] The lower part of the sound collection channel 200 is opposite to the first sound inlet 211 at the front of the accommodation groove 21 of the mounting bracket 20 in the front-rear direction. After the wind shield 40 is installed, it can effectively prevent the high-speed oil fume airflow from directly impacting the wind-proof sound-transmitting member 30, greatly reducing the pollution of the oil fume to the wind-proof sound-transmitting member 30. At the same time, after the wind shield 40 is combined with the mounting bracket 20, only the second sound inlet 45 at the upper part is reserved, directly isolating the lower airflow noise and the noise interference of the secondary turbulent flow, so that the noise entering the wind-proof sound-transmitting member 30 mainly comes from above, that is, the direction of the main noise source of the range hood, thus ensuring the accuracy of noise collection. In a preferred embodiment, in order to improve the protection effect of the wind shield 40 on the wind-proof sound-transmitting member 30 and minimize the contact between the wind-proof sound-transmitting member 30 and the flue gas in the air duct, an extension wall 46 extends upward from the upper edge of the wind shield 40 relative to the top surface of the wind-proof sound-transmitting member 30, that is, the top edge of the extension wall 46 is higher than the top surface of the wind-proof sound-transmitting member 30. Affected by the airflow in the air duct 10, an airflow vortex will be formed at the leeward end of the wind shield 40 (that is, at the second sound inlet 45), which will generate obvious wind noise. The setting of the extension wall 46 of the wind shield 40 can make the airflow vortex as far away from the second sound inlet 45 as possible, avoiding the influence of the airflow vortex on the target noise to be collected entering from the second sound inlet 45.

[0075] Since the sound collection element 11 is installed in the receiving groove 21 of the mounting bracket 20 and a windproof cover 40 is provided outside the mounting bracket 20, it is possible to effectively isolate the interference of the airflow in the air duct 10 on the sound collection element 11, prevent the oil stain in the airflow from contaminating the sound collection element 11, and at the same time, a windproof and sound-permeable member 30 is provided in the sound collection channel formed between the mounting bracket 20 and the windproof cover 40, which can effectively reduce the influence of wind noise. Even if a small amount of airflow enters the sound collection channel 200, the pressure pulsation can be weakened in the windproof and sound-permeable member 30, thereby reducing the influence on the sound collection accuracy of the microphone. In addition, considering that the noise in the air duct 10 (mainly from the fan system) propagates along the extension direction of the air duct 10 and the propagation direction is opposite to the airflow direction in the air duct 10, therefore, arranging the sound collection channel 200 along the extension direction of the air duct can make the second sound inlet 45 of the sound collection channel 200 face the sound source so as to directly receive the noise. And considering that it is necessary to set a windproof and sound-permeable member 30 with a sufficient length on the sound propagation path to prevent wind noise, thereby reducing the influence of the airflow in the air duct 10 on sound collection. In this embodiment, the sound collection channel 200 for placing the windproof and sound-permeable member 30 is arranged in the extension direction of the air duct 10, so that the size of the entire sound collection device in the direction perpendicular to the air duct extension direction can be made smaller, that is, it occupies less space in the air duct 10 of the range hood, and further makes the wind resistance at the position where the sound collection device is located in the air duct 10 smaller. Therefore, it will not affect the stability of the airflow in the air duct 10 and at the same time reduces the generation of wind noise to a certain extent. On this basis, considering that the air duct environment of the range hood is full of oil stains, if the opening direction B1 of the first sound inlet 211 is consistent with the extension direction B3 of the sound collection channel 200, then the sound collection element 11 is easily contaminated by the oil stains flowing down along the air duct 10. Therefore, in this embodiment, the opening direction B1 of the first sound inlet 211 of the receiving groove 21 and the extension direction B3 of the sound collection channel 200 are set at a certain angle, which makes the entire sound propagation path from the noise in the air duct 10 entering the sound collection channel 200 from the second sound inlet 45 and then propagating to the position of the sound collection element 11 in the receiving groove 21 a turning path. This turning path can prevent too much oil stain from directly passing through the sound collection channel 200 and contacting the sound collection element 11, but makes most of the oil stains adhere to the side wall of the sound collection channel 200 or the windproof and sound-permeable member 30, thereby enabling the sound collection element 11 to be as far away from the oil stains as possible and extending the service life of the sound collection element 11.Furthermore, considering that the target noise to be collected by the active noise cancellation system (mainly from the fan system) is low-frequency noise, the sound propagation path in the sound collection device is designed with a turning path, which has a weakening effect on high-frequency sounds (such as the high-frequency sound components in wind noise and the high-frequency sound components generated by the fan system, etc., which are non-target noises), and has little impact on low-frequency sounds. Therefore, it can be better applied to the propagation of low-frequency noise in the sound collection device, which is beneficial for the sound collection element 11 to accurately collect it. The main reason is that the wavelength of low-frequency noise is longer, and it can better adapt to the bending and irregular shapes of the pipeline. When low-frequency noise propagates in a bent pipeline, due to its longer wavelength, it is not easily blocked and reflected by the pipeline, so it can better propagate and spread. While the wavelength of high-frequency noise is shorter, it is easily reflected and absorbed by the shape and bending of the pipeline, so it is more difficult to propagate and spread in the pipeline compared to low-frequency noise.

[0076] The oil-proof sound-permeable membrane 28 covers the first sound inlet 211 of the receiving groove 21 of the mounting bracket 20, specifically at the position where the edge of the front opening of the receiving groove 21 of the mounting bracket 20 is located. More specifically, in order to facilitate the installation of the oil-proof sound-permeable membrane 28 and ensure its sealing performance after installation, an annular step portion 210 is further formed at the edge position of the first sound inlet 211 of the receiving groove 21, and the oil-proof sound-permeable membrane 28 is disposed on the annular step portion 210. In order to ensure the oil-proof performance of the oil-proof sound-permeable membrane 28 and enable it to effectively transmit sound waves, the oil-proof sound-permeable membrane 28 of this embodiment is preferably a polyethylene film. Among them, as Figure 3 shown, there is a fourth distance between the oil-proof sound-permeable membrane 28 and the sound collection element 11, which is denoted as f. Among them, the value range of f is: f≥0.1mm, the preferred range is: 0.5 - 3mm, and the more preferred range is: 2 - 3mm. Thus, it avoids the contact between the film vibration or micro-deformation and the sound collection element 11, resulting in sound propagation variation and affecting the accuracy of sound collection. It can be understood that the fourth distance f between the above-mentioned oil-proof sound-permeable membrane 28 and the sound collection element 11 should refer to the distance between the oil-proof sound-permeable membrane 28 and the microphone chip on the sound collection element 28, that is, the oil-proof sound-permeable membrane 28 can have partial contact with other components (such as solder joints or fixing screws, etc.) on the circuit board where the microphone chip is located.

[0077] In order to effectively slow down the airflow and eliminate the airflow impact, the windproof sound-permeable member 30 is a sleeve member made of porous sound-absorbing material. For example, the windproof sound-permeable member 30 can be made of polyurethane foam, melamine foam sponge, etc. Among them, the porosity of the windproof sound-permeable member 30 is greater than 70%. The windproof sound-permeable member 30 of this embodiment can not only prevent the airflow from impacting the oil-proof sound-permeable film 28 and generating additional noise, but also, due to the property of its porous material itself, can absorb the high-frequency components in the sound energy and achieve the filtering function of filtering the noise signal. More specifically, the front side wall of the windproof sound-permeable member 30 is attached to the rear side wall of the third side wall 413 of the windproof cover 40, so that the windproof sound-permeable member 30 is in a compressed state. By compression, the material density can be increased, and the possibility of the penetration of the airflow pressure pulsation can be effectively reduced, thereby further improving the windproof effect. In order to prevent the oil-proof sound-permeable film 28 from contacting the windproof sound-permeable member 30 and affecting the sound transmission effect here, the sixth distance n between the oil-proof sound-permeable film 28 and the windproof sound-permeable member 30 should be greater than 0.1 mm, and the preferred range is 0.5 mm to 3 mm.

[0078] The windproof sound-permeable member 30 of this embodiment includes an extension section 301 extending upward from the top edge of the first sound inlet 211 of the accommodation groove 21, and the length of the extension section 301 of the windproof sound-permeable member 30 is denoted as h, and the size of the first sound inlet 211 of the accommodation groove 21 in the up-down direction is m. Among them, the value range of h / m is: 0.125 ≤ h / m ≤ 0.6. Since the sound collection channel 200 has a vertical section extending vertically and a horizontal section extending front and back, that is, there is a turning part at the first sound inlet 211 of the accommodation groove 21. If the extension length of the outer peripheral edge part of the windproof sound-permeable member 30 relative to the edge of the first sound inlet 211 of the accommodation groove 21 is too short (such as h / m is less than 0.125), it will also be affected by relatively large wind noise. After the above parameter design, the windproof effect of the windproof sound-permeable member is effectively guaranteed, and the accuracy of sound collection is prevented from being affected due to the too short extension length of the outer peripheral edge of the windproof sound-permeable member. Of course, considering the adverse effect of the windproof sound-permeable member 30 on sound attenuation, the length dimension of the extension section 301 of the windproof sound-permeable member 30 should not be too large. If h / m is greater than 0.6, it will cause the sound not to effectively meet the sound pressure requirements of the sound collection element 11 when propagating to the accommodation groove 21, and reduce the accuracy of noise collection.

[0079] To avoid the windproof sound-permeable member 30 from contacting the oil flowing continuously on the side wall of the air duct 10, after being installed on the mounting bracket 20, there is a first spacing between the windproof sound-permeable member 30 and the rear side wall of the air duct 10, which is denoted as d. Among them, the value range of d is: d≥4mm. Similarly, to ensure the windproof effect, the dimension (i.e., thickness) of the main body of the windproof sound-permeable member 30 in the front-rear direction is denoted as e. Among them, the value range of e is: 40mm≥e≥3mm. Specifically, when e≥3mm, it can ensure that the windproof sound-permeable member 30 effectively avoids the airflow in the air duct from directly impacting the sound collection element 11. Of course, considering the adverse effect of the windproof ball 30 (generally made of porous materials that can prevent airflow disturbance and transmit sound) on sound attenuation, the dimension (i.e., thickness) of the windproof sound-permeable member 30 in the front-rear direction cannot be too large, and e≤40mm is required. At the same time, when the dimension (i.e., thickness) of the windproof sound-permeable member 30 in the front-rear direction is fixed, the dimension d1 of the main body of the windproof sound-permeable member 30 in the left-right direction also needs to be adapted to it, that is, it is necessary to reasonably limit e / d1. Specifically, if e / d1 is too small (such as e / d1<0.2), it means that the dimension of the main body of the windproof sound-permeable member 30 in the left-right direction is large, and the area of its upper part in contact with oil stains increases, which will directly affect the service life of the windproof sound-permeable member 30. If e / d1 is too large (such as e / d1>0.5), it means that the dimension of the main body of the windproof sound-permeable member 30 in the left-right direction is small, which is not conducive to the sound being transmitted into the sound collection channel 200 from a large angle range in the horizontal direction above, affecting the accuracy of sound collection.

[0080] Due to the setting of the windproof sound-permeable member 30 in the sound collection channel 200, there will be a certain loss in the propagation path of the sound from the second sound inlet 45 to the position where the sound collection element 11 is located, that is, a part of the sound pressure will be lost. Therefore, it is necessary to ensure that a sufficient amount of noise to be collected enters the receiving groove 21 of the mounting bracket 20 to be received by the sound collection element 11 and achieve the purpose of accurately collecting the noise signal. Specifically, the principles of sound attenuation and compensation are as follows:

[0081] L w =L1 - ΔL + 10lgS0

[0082] Among them, the noise energy that the sound collection component can collect per unit time is the sound power L w ;

[0083] The sound pressure when the sound reaches the top surface of the windproof sound-permeable member 30 is L1;

[0084] Due to the attenuation effect of the windproof sound-permeable member 30, the lost noise sound pressure is ΔL;

[0085] The cross-sectional area S0 of the second sound inlet 45 of the sound collection channel 200;

[0086] Therefore, if the thickness of the windproof sound transmission member 30 or the length dimension in the sound propagation path is too large, resulting in serious sound attenuation, then by increasing S0, the sound power L collected by the sound collection element can be ensured w will not become smaller, thereby ensuring the accuracy of sound collection. Specifically, the ratio of the area S0 of the cross-section at the second sound inlet 45 of the sound collection channel 200 of this embodiment to the opening area S of the first sound inlet 211 at the front part of the accommodation groove 210 needs to be reasonably limited. Among them, S0 / S≥0.18, so that it can be ensured that enough noise can pass through the sound collection channel 200 of the sound collection device, compensating for the sound pressure loss caused by the setting of the windproof sound transmission member 30, and further ensuring that the sound can meet the sound pressure requirements of the sound collection element 11 when propagating to the second sound inlet 45, further improving the accuracy of noise collection.

[0087] On the other hand, the dimension of the main body of the windproof sound transmission member 30 in the up-down direction in this embodiment is denoted as g. In order to adapt to the dimension of the first sound inlet 211 at the front part of the accommodation groove 210 and ensure the windproof effect, 100mm≥g≥10mm. The cross-sectional area of the main body of the windproof sound transmission member 30 near the second sound inlet 45 is S1. Among them, g / 2+e / 2 represents the sound propagation path length in the windproof sound transmission member. When the propagation path is long, the sound loss is more. According to the sound propagation principle L w =L1+10lgS (L W is the sound power, L1 is the sound pressure, and S is the area of the sound inlet), it can be seen that the sound pressure decreases during the sound propagation due to the sound loss. As a compensation, S1 should be increased at this time to ensure that enough sound is collected by the sound collection element. Therefore, considering the sound propagation loss and compensation, the value of S1 / (g / 2+e / 2) should be greater than 8mm, and the preferred value range is: 10mm~15mm. If S1 / (g / 2+e / 2) is too small, such as S1 / (g / 2+e / 2)≤8, it means that the inlet area for the sound to effectively transmit from top to bottom at the end position of the windproof sound transmission member near the second sound inlet is small, and the amount of sound entering is not enough to balance the adverse effects of the windproof sound transmission member 30 on the sound loss in the up-down direction and the front-back direction, reducing the accuracy of the sound collection element 11. If S1 / (g / 2+e / 2) is too large, such as S1 / (g / 2+e / 2)≥15, it means that the inlet area for the sound to effectively transmit from top to bottom at the end position of the windproof sound transmission member 30 near the second sound inlet 45 is large. Similarly, the area of the upper part of the windproof sound transmission member 30 in contact with the oil stain increases, affecting the service life of the windproof sound transmission member 30.

[0088] In this embodiment, since the windproof sound-permeable member 30 is filled in the sound collection channel 200, that is, there is no gap between the front side of the windproof sound-permeable member 30 and the windproof cover 40, the cross-sectional area S1 of the main body of the windproof sound-permeable member 30 near the second sound inlet 45 is substantially the same as the area S0 of the cross-section of the second sound inlet 45 of the sound collection channel 200.

[0089] While the protection structure of this embodiment realizes the suppression of wind noise by the sound collection element, it also needs to ensure the passage of noise signals. According to the sound propagation theory, the protection structure consists of acoustic mass M a and acoustic compliance C a to form a low-pass filter. Therefore, it is necessary to make the cut-off frequency f c of the structure itself greater than the upper frequency limit f a concerned by active noise reduction, so as to accurately collect all the original noise frequencies concerned by active noise reduction.

[0090] Where:

[0091]

[0092] V is the volume of the cavity in the protection structure, specifically the volume of the inner cavity formed by the oil-proof sound-permeable membrane and the inner wall of the receiving groove of the mounting bracket; ρ0 is the air density; c0 is the speed of sound in air, 343 m / s; L is the path length of sound propagation;

[0093] S0 is the effective area of sound propagation in the pipeline, which can be simplified to take the minimum cross-sectional area of the pipeline during sound propagation. In this embodiment, S0 is the area of the cross-section of the second sound inlet 45 of the sound collection channel 200;

[0094]

[0095] The applicant's research found that due to the structural limitations of the range hood and the noise source and its propagation characteristics, for the upper frequency limit f a concerned by the active noise reduction of the range hood, it should be 1200 - 2000 Hz. Therefore, it can be obtained that:

[0096]

[0097] After simplification, it is:

[0098]

[0099] The protection structure of this embodiment must meet the requirements of the above formula.

[0100] More specifically, in this embodiment, S0 is the area of the cross-section of the second sound inlet 45 of the sound collection channel 200, where the second sound inlet 45 is a strip-shaped opening. Thus:

[0101] S0=ed;

[0102] L is the path length of sound propagation. Since the sound collection channel 200 in this embodiment is not a regular pipe, it can be simplified as follows:

[0103]

[0104] The size of the windproof and sound-permeable member 30 in the vertical direction is recorded as g, and the size of the main body of the windproof and sound-permeable member 30 in the front-to-back direction (ie, thickness) is recorded as e.

[0105] The above

[0106] Further simplification:

[0107]

[0108] Since there is a large difference in wavelength between high-frequency sound waves and low-frequency sound waves, high-frequency noise can be rapidly attenuated as the propagation distance increases or when encountering obstacles. Since the wavelength of low-frequency noise is longer, low-frequency noise is relatively stable during the propagation process and can penetrate obstacles. Therefore, the sound propagation path in the sound collection device of this embodiment adopts a turning design to increase the reflection and scattering of high-frequency sound waves and increase their propagation resistance. For low-frequency sound waves, due to their larger wavelength, they are not affected by the turning of the sound propagation path. Therefore, it is equivalent to adjusting the propagation characteristics of noise in different frequency bands in the channel, thereby achieving the purpose of weakening high-frequency noise and ensuring the propagation of low-frequency noise. In order to achieve the purpose of weakening high-frequency noise above frequency f0, see Figure 4 The sound propagation path in the sound collection device is divided into three regions. The horizontal plane passing through the upper edge of the first sound inlet 211 is used as the first reference plane k1, the horizontal plane passing through the lower edge of the first sound inlet 211 is used as the second reference plane k2, the vertical plane where the first sound inlet 211 is located is used as the third reference plane k3, the horizontal plane where the second sound inlet 45 is located is used as the fourth reference plane k4, and the vertical plane passing through the location of the sound collection element 11 is used as the fifth reference plane k5. The area of the region between the first reference plane k1 and the fourth reference plane k4 on a vertical cross-section of the sound collection channel 200 taken along the front-to-back direction is recorded as S. 01 The area between the first reference plane k1 and the second reference plane k2 is denoted as S 02 The area of the vertical cross section of the receiving groove 21 cut along the front-to-back direction between the third reference plane k2 and the fifth reference plane k5 is recorded as S 03 , where the values of the above areas meet the conditions:

[0109]

[0110] The dimension of the first sound inlet 211 in the up-down direction is denoted as m, the dimension of the second sound inlet 45 in the left-right direction is denoted as d1, and the dimension of the second sound inlet 45 in the front-back direction is denoted as e. The following conditions are satisfied among the above three:

[0111]

[0112] where f0 is the lowest noise frequency of the high-frequency noise to be attenuated, and v is the sound propagation speed.

[0113] After installing the sound collection element 11 in the accommodation groove 21 of the mounting rack 20 in this embodiment, an oil-proof sound-transmitting film 28 is provided at the first sound inlet 211 thereof, a wind-proof sound-transmitting member 30 is provided outside thereof, and a wind-proof cover 40 is provided outside the wind-proof sound-transmitting member 30. This kind of sound collection device adopts the above three-layer protection to effectively eliminate wind noise and achieve the purpose of preventing oil pollution. After the wind-proof cover 40 covers the wind-proof sound-transmitting member 30, a second sound inlet 45 communicating with the outside is reserved at the leeward end. According to the air flow law, the flow in the area of the wind-proof sound-transmitting member 30 adjacent to the second sound inlet 45 is a low-speed and high-static-pressure area. The existence of the low-speed and high-static-pressure area reduces the wind noise here, and further ensures that the target noise to be collected (i.e., the noise of the fan system) can be effectively transmitted to the accommodation groove 21 of the mounting rack 20 through the above second sound inlet 45, ensuring the accuracy of noise data collection. On the other hand, considering the influence of the wind-proof sound-transmitting member 30 and the wind-proof cover 40 on the sound propagation obstruction and loss, the ratio of the opening area S at the first sound inlet of the accommodation groove 21 to the opening area S0 at the second sound inlet 45 of the sound collection channel 200 is limited within a reasonable value range, which can ensure that enough noise passes through this sound collection device and is received by the sound collection element, further improving the accuracy of noise collection.

[0114] This embodiment also relates to an oil fume extractor, which includes a flue 10 for the passage of flue gas and an active noise reduction system provided in the flue 10. The active noise reduction system includes a sound collection element 11 for collecting sound signals. The sound collection element 11 adopts a microphone, and the microphone is arranged in the accommodation groove 21 of the mounting rack 20 of the above sound collection device, and then is installed on the side wall of the flue 10 through this sound collection device.

[0115] Embodiment 2

[0116] Figure 9 and Figure 10Another preferred embodiment of the sound collection device and range hood of the present invention is shown. This embodiment differs from the first embodiment in that the entire sound collection channel 200 is a vertically extending linear channel. The sound collection channel 200 has a certain inclination angle relative to the vertical direction. Specifically, the opening direction of the first sound inlet 211 of the receiving slot 21 of the mounting frame 20 is horizontal. The sound collection channel 200 is inclined from top to bottom toward the location of the receiving slot 21 of the mounting frame 20. The first angle M formed between the direction of the first sound inlet 211 and the extension direction of the sound collection channel 200 is an acute angle, with a value range of 5°≤M<90°. Preferably, the value range of the first angle M is 30°≤M≤80°, wherein the magnitude of the first angle M is consistent with the deflection angle of the path during sound propagation. Figure 9 It can be seen that the propagation path of the sound in the sound collection device of this embodiment is a turning path, such as Figure 9 The turning path S is shown in FIG. Since the turning angle of the sound propagation path of this embodiment is relatively gentle compared to that of (Example 1), while achieving the purpose of oil prevention, it can also avoid as much as possible the target noise loss caused by excessive turning angles, which affects the accuracy of sound collection.

[0117] This embodiment also relates to a range hood, comprising an air duct 10 for smoke to pass through and an active noise reduction system provided in the air duct 10. The active noise reduction system includes a sound collecting element 11 for collecting sound signals. The sound collecting element 11 is a microphone. The microphone is provided in a receiving groove 21 of a mounting bracket 20 of the above-mentioned sound collecting device, and then mounted on the side wall of the air duct 10 through the sound collecting device.

[0118] Example 3

[0119] Figures 11 - 14Another preferred embodiment of the sound collection device and the range hood of the present invention is shown. The difference between this embodiment and Embodiment 1 is that: the sound collection channel 200 extends vertically as a whole, and it includes two sections arranged in sequence from top to bottom, specifically including an upper section 201 (i.e., a vertical section) extending vertically and a lower section 202 (i.e., an inclined section) inclined downward from top to bottom toward the accommodation groove 21 of the mounting bracket 20. Among them, the upper section 201 of the sound collection channel 200 is the main part of the sound collection channel 200. The opening direction B1 of the first sound inlet 211 of the accommodation groove 21 of the mounting bracket 20 is set obliquely upward, and its inclination direction is the same as the inclination direction of the lower section 202 of the sound collection channel 200. More specifically, the first included angle M formed between the opening direction B1 of the first sound inlet 211 and the extension direction of the upper section 201 of the sound collection channel 200 is also an acute angle, and the value range is: 5° ≤ M < 90°. Preferably, the value range of the first included angle M is: 30° ≤ M ≤ 80°. The parts of the front wall surface of the mounting bracket 20 corresponding to the upper section 201 and the lower section 202 of the sound collection channel 200 are a vertical surface 20a and an inclined surface 20b respectively. In addition, through Figure 12 It can be seen that the position of the vertical surface 20a of the mounting bracket 20 is displaced in the vertical direction from the position of the accommodation groove 21 (i.e., the position where the sound collection element 11 is located), that is, the sound collection element 11 is closer to the side wall of the air duct 10 for mounting the mounting bracket 20, while the vertical surface 20a of the mounting bracket 20 is relatively far from the side wall of the air duct 10 for mounting the mounting bracket 20.

[0120] In this embodiment, the vertical surface 20a and the inclined surface 20b of the mounting bracket 20 intersect to form a second included angle N. Due to the differences in the viscosity, surface tension of the oil droplets themselves and the roughness of the wall material, the oil droplets are subject to gravity, adhesion force, surface tension, and friction force on the inclined surface. When the inclination angle of the inclined surface 20b is different (i.e., the second included angle N), the combined action of different forces results in different movement conditions of the oil droplets. As shown in Fig. 12, when the value of the second included angle N is 80° ≥ N ≥ 30°, since the components of the adhesion force and the friction force resisting gravity in the vertical direction are small, the oil stain flows down from the vertical surface 20a and accumulates at the corner. After increasing to a certain extent, it directly drops, and due to the misaligned design in the structure, the oil droplets will not drip onto the sound collection element 11. And as Figure 14As shown, when the second angle N is 30° > N ≥ 5°, due to the greater vertical component of adhesion and friction forces resisting gravity, oil will flow down vertical surface 20a, past the corner, and along inclined surface 20b, reaching sound collecting element 11. Therefore, the lower end of vertical surface 20a of mounting bracket 20, where it meets inclined surface 20b, is provided with a downwardly extending overhanging edge 20c. By adding an overhanging edge 20c at the corner where vertical surface 20a and inclined surface 20b meet, oil droplets gradually accumulate along overhanging edge 20c and drip vertically, preventing them from falling onto sound collecting element 11.

[0121] The propagation path of the sound in the sound collecting device of this embodiment is a turning path, such as Figure 11 and Figure 13 Path S is shown in Figure 1. Because the sound propagation path of this embodiment has a gentler turning angle than that of Example 1, it achieves oil protection while minimizing target noise loss caused by excessive turning angles, which could affect the accuracy of sound collection. Furthermore, compared to Example 2, the sound collection channel 200 of this embodiment is positioned as close as possible to the sidewall of the air duct 10, preventing the sound collection device from protruding excessively from the sidewall within the air duct 10 and potentially affecting the stability of the airflow within the air duct 10.

[0122] This embodiment also relates to a range hood, comprising an air duct 10 for smoke to pass through and an active noise reduction system provided in the air duct 10. The active noise reduction system includes a sound collecting element 11 for collecting sound signals. The sound collecting element 11 is a microphone. The microphone is provided in a receiving groove 21 of a mounting bracket 20 of the above-mentioned sound collecting device, and then mounted on the side wall of the air duct 10 through the sound collecting device.

[0123] Example 4

[0124] Figure 15 and Figure 16 Another preferred embodiment of the sound collection device and range hood of the present invention is shown. This embodiment differs from the first embodiment in that the sound collection channel 200 is a vertically extending linear channel, while the opening of the first sound inlet 211 of the receiving slot 21 of the mounting frame 20 is oriented diagonally downward. The sound collection element 11 in the receiving slot 21 is located at a higher height than the opening of the first sound inlet 211. The first angle M formed between the opening direction of the first sound inlet 211 and the extension direction of the sound collection channel 200 is an obtuse angle, with a value range of 90° < M < 180°. Preferably, the value range of the first angle M is 100° < M < 150°. Figure 15As can be seen, the propagation path of sound in the sound collection device of this embodiment is a turning path of "first downward and then obliquely upward", as Figure 15 The path S shown therein. Since the turning angle of the sound propagation path in this embodiment is relatively large (compared with Embodiment 1), especially, the opening of the first sound inlet 211 is set obliquely downward, so a better oil prevention purpose can be achieved. However, due to the excessive turning angle, certain losses are caused to the target noise, which has a certain impact on the accuracy of sound collection.

[0125] This embodiment also relates to a range hood, which includes a flue 10 for the passage of flue gas and an active noise reduction system provided in the flue 10. The active noise reduction system includes a sound collection element 11 for collecting sound signals. The sound collection element 11 uses a microphone, and the microphone is disposed in the receiving groove 21 of the mounting bracket 20 of the above-mentioned sound collection device, and then is installed on the side wall of the flue 10 through this sound collection device.

[0126] Embodiment 5

[0127] Figure 17 and Figure 18 shows another preferred embodiment of the sound collection device and the range hood of the present invention. The difference between this embodiment and Embodiment 1 is that: the sound collection channel 200 includes a vertically extending section 203 and a horizontal section 204 connected to the bottom of the vertically extending section 203. The vertically extending section 203 is the main part of the sound collection channel, and it is a straight channel extending vertically. The lower end of the main body of the sound collection channel 200 is connected to one end of the horizontal section 204, and the opening direction of the first sound inlet 211 of the receiving groove 21 of the mounting bracket 20 faces downward and is connected to the other end of the horizontal section 204 of the sound collection channel 200. The first included angle M formed between the orientation of the first sound inlet 211 and the extending direction of the main body of the sound collection channel 200 is a flat angle, that is, the value range of the first included angle M is 180°. As can be seen from Figure 17 As can be seen, the propagation path of sound in the sound collection device of this embodiment is a turning path of "first propagating downward, then propagating horizontally, and finally propagating upward", as Figure 17 The turning path S shown therein. Since the sound collection channel of this embodiment is divided into two sections, a vertically arranged section and a horizontally arranged section, and the opening direction of the first sound inlet 211 faces downward, the sound propagation path in the sound collection device of this embodiment has undergone two "turns". Therefore, a better oil prevention purpose can also be achieved. However, due to the excessive turning angle and the large number of turns, certain losses are caused to the target noise, which has a certain impact on the accuracy of sound collection.

[0128] This embodiment also relates to a range hood, which includes an air duct 10 for flue gas to pass through and an active noise reduction system disposed in the air duct 10. The active noise reduction system includes a sound collection element 11 for collecting sound signals. The sound collection element 11 is a microphone, and the microphone is disposed in the receiving groove 21 of the mounting bracket 20 of the above-mentioned sound collection device, and then is mounted on the side wall of the air duct 10 through this sound collection device.

Claims

1. A sound collection device, comprising a sound collection element (11), characterized in that: It further includes a housing (2) on which a sound propagation channel is defined. The sound propagation channel includes a first channel section and a second channel section connected in sequence. The sound collection element (11) is located in the first channel section. The first channel section has a first sound inlet (211) communicating with the second channel section. The second channel section has a second sound inlet (45) for external sound to enter therein. The opening direction of the second sound inlet (45) is upward. The opening direction of the first sound inlet (211) intersects with the extending direction of the main body of the second channel section to form a first included angle, and this first included angle is greater than 0°.

2. The sound collection device according to claim 1, wherein: The above-mentioned sound collection device is arranged in the air duct (10) of the oil fume extraction device. The second channel section is arranged along the extending direction of the air duct (10), and the second sound inlet (45) is formed at the windward end of the housing (2).

3. The sound collection device according to claim 2, characterized in that: The opening direction of the second sound inlet (45) is consistent with the extending direction of the main body of the second channel section.

4. The sound collection device according to any one of claims 1 to 3, characterized in that: The housing (2) includes a mounting bracket (20) and a wind shield (40). A receiving groove (21) is formed on the front side wall of the mounting bracket (20). The sound collection element (11) is placed in the receiving groove (21). The receiving groove (21) constitutes the first channel section. The front opening of the receiving groove (21) is the first sound inlet (211). The wind shield (40) covers outside the mounting bracket (20), and a sound collection channel (200) communicating with the first sound inlet (211) of the receiving groove (21) and located on the front side of the receiving groove (21) is defined between the wind shield (40) and the mounting bracket (20). The sound collection channel (200) constitutes the second channel section.

5. The sound collection device according to claim 4, wherein: The first included angle formed by the opening direction (B1) of the first sound inlet (211) and the extending direction of the main body of the second channel section is denoted as M, and its value range is: 5° ≤ M ≤ 180°.

6. The sound collection device according to claim 5, characterized in that: The main body of the second channel section extends vertically, and the opening direction (B1) of the first sound inlet (211) is horizontally arranged, that is, the opening direction (B1) of the first sound inlet (211) is perpendicular to the extending direction of the main body of the second channel section; or The main body of the second channel section extends vertically, and the opening direction (B1) of the first sound inlet (211) is obliquely upward, that is, the value range of the first included angle formed by the opening direction (B1) of the first sound inlet (211) and the extending direction of the main body of the second channel section is: 5° ≤ M < 90°; or The main body of the second channel section extends vertically, and the opening direction (B1) of the first sound inlet (211) is obliquely downward, that is, the value range of the first included angle formed by the opening direction (B1) of the first sound inlet (211) and the extending direction of the main body of the second channel section is: 90° < M < 180°; or The second channel section includes a vertically extending section and a horizontal section (204) connected to the bottom of the vertically extending section. The opening direction (B1) of the first sound inlet (211) faces downward and is connected to the horizontal section (204).

7. The sound collection device according to claim 6, characterized in that: The main body of the second channel section extends vertically. The opening direction (B1) of the first sound inlet (211) is set obliquely upward. The value range of the first included angle formed by the opening direction (B1) of the first sound inlet (211) and the extending direction of the main body of the second channel section is: 30° ≤ M ≤ 80°; or The main body of the second channel section extends vertically. The opening direction (B1) of the first sound inlet (211) is set obliquely downward. The value range of the first included angle formed by the opening direction (B1) of the first sound inlet (211) and the extending direction of the main body of the second channel section is: 100° < M < 150°.

8. The sound collection device according to claim 6, wherein: The second channel section includes a vertical section (201) arranged successively from top to bottom and an inclined section (202) inclined from the bottom of the vertical section (201) toward the side where the receiving groove (21) is located. The opening of the first sound inlet (211) is connected to the inclined section (202) of the second channel section. The front wall surface of the mounting bracket (20) includes a vertical surface (20a) corresponding to the vertical section (201) of the second channel section and an inclined surface (20b) corresponding to the inclined section (202) of the second channel section. The vertical surface and the inclined surface intersect to form a second included angle. The vertical surface (20a) of the mounting bracket (20) is arranged out of alignment with the receiving groove in the vertical direction. The bottom of the vertical surface (20a) of the mounting bracket (20) also has a downward-extending overhanging edge (20c).

9. The sound collection device according to claim 4, wherein: One end of the wind shield (40) facing the wind has a guiding surface (4130) that gradually inclines toward the inside of the air duct (10) along the air flow direction inside the air duct (10).

10. The sound collection device according to claim 9, characterized in that: The mounting bracket (20) and the wind shield (40) are mounted on the side wall of the air duct (10). The included angle formed between the guiding surface (4130) of the wind shield (40) and the side wall of the air duct (10) for mounting the wind shield (40) is denoted as A, and the value range of A is: A ≤ 60°.

11. The sound collection device according to claim 9, wherein: Along the air flow direction inside the air duct (10), the position where the guiding surface (4130) of the wind shield (40) is located is upstream of the position where the receiving groove (21) of the mounting bracket (20) is located.

12. The sound collection device according to claim 9, wherein: The wind shield (40) includes a first side wall (411) and a second side wall (412) that are opposite and spaced apart from each other left and right, and a third side wall (413) connected between the front side edges of the first side wall (411) and the second side wall (412). The third side wall (413) is opposite to the first sound inlet (211) on the mounting bracket (20). The guiding surface (4130) is provided at one end of the third side wall (413) facing the wind.

13. The sound collection device according to any one of claims 1 to 12, characterized in that: It further includes a windproof and sound-permeable member (30), which is arranged in the second channel section and blocks the first sound inlet (211).

14. The sound collection device according to claim 6, characterized in that: The main body of the second channel section extends vertically, with the horizontal plane passing through the upper edge of the first sound inlet (211) as the first reference plane, the horizontal plane passing through the lower edge of the first sound inlet (211) as the second reference plane, the vertical plane where the first sound inlet (211) is located as the third reference plane, the horizontal plane where the second sound inlet (45) is located as the fourth reference plane, and the vertical plane passing through the location of the sound collecting element (11) as the fifth reference plane. The area of the region between the first reference plane and the fourth reference plane on the vertical cross section of the second channel section cut along the front-to-back direction is recorded as S 01 The area between the first reference plane and the second reference plane is denoted as S 02 The area of the vertical cross section of the receiving groove (21) cut along the front-to-back direction between the third reference plane and the fifth reference plane is recorded as S 03 , where S 01 、S 02 、S 03 The value of satisfies the conditions: The size of the first sound inlet (211) in the up-down direction is denoted as m, the size of the second sound inlet (45) in the left-right direction is denoted as d1, and the size of the second sound inlet (45) in the front-back direction is denoted as e. m, d1, and e satisfy the condition: Where f0 is the lowest noise frequency of the high-frequency noise that needs to be attenuated, and v is the sound propagation speed.

15. A range hood, comprising an air duct (10) for flue gas to pass through and a sound collection device disposed in the air duct (10), characterized in that: The sound collection device adopts the sound collection device described in any one of claims 1 to 14.

16. The range hood according to claim 15, characterized in that: The sound collection element (11) is a microphone.

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