Sound acquisition device and range hood

Abstract

The utility model relates to a sound acquisition device and a range hood, the sound acquisition device comprises a sound acquisition element and also comprises a shell, the sound acquisition element is arranged in the shell, and a sound transmission channel for transmitting external sound to the position of the sound acquisition element is defined on the shell. An oil-proof sound transmission film and a windproof sound transmission part are further arranged in the sound transmission channel, and the oil-proof sound transmission film is arranged close to the sound collection element relative to the windproof sound transmission part in the extension direction of the sound transmission channel and is spaced from the sound collection element and the windproof sound transmission part by a certain distance. The sound collection element is not in contact with the oil-proof sound transmission film, so that sound transmission variation caused by vibration or micro-deformation of the oil-proof sound transmission film in contact with the sound collection element is avoided, and the sound collection accuracy is not influenced. And the windproof sound-transmitting piece is not in contact with the oil-proof sound-transmitting film, so that oil stains attached to the oil-proof sound-transmitting film are reduced, and the service life of the oil-proof sound-transmitting film is prolonged.

Description

Technical Field

[0001] The utility model relates to the technical field of range hoods, in particular 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, so as to achieve 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 outer shell and surrounds the blower in an array distribution manner, and the speaker assembly is distributed below the blower.

[0003] However, in the prior art, the microphones and speakers used in the active noise reduction system are often arranged in the internal air duct of the range hood. Due to the oil pollution environment of the range hood, the microphones and speakers are often polluted, resulting in the reduction of the noise reduction effect of the active noise reduction system over time and even the occurrence of failures. On the other hand, the microphone of the active noise reduction system is arranged in the air duct through the installation component, which will generate a large amount of wind noise around the microphone collection area. However, the microphone installation device in the prior art of the active noise reduction system does not consider the influence of the wind noise in the air duct of the range hood, that is, no effective anti-wind noise treatment is carried out, thus greatly affecting the accuracy of the sound collection of the microphone of the active noise reduction system. Summary of the Utility Model

[0004] The first technical problem to be solved by the utility model is to provide a sound collection device according to the current situation of the prior art, which can effectively reduce the erosion of the sound collection element by oil pollution and has a good anti-wind noise effect.

[0005] The second technical problem to be solved by the utility model is to provide a range hood applying the above sound collection device according to the current situation of the prior art.

[0006] The technical solution adopted by the present utility model to solve the first technical problem is as follows: A sound collection device includes a sound collection element and also includes a housing. The sound collection element is arranged inside the housing. A sound propagation channel for transmitting external sound to the position of the sound collection element is defined on the housing. An oil-proof sound-transmitting membrane and a wind-proof sound-transmitting member are also provided in the sound propagation channel. Along the extending direction of the sound propagation channel, the above-mentioned oil-proof sound-transmitting membrane is arranged adjacent to the sound collection element relative to the wind-proof sound-transmitting member, and is spaced apart from both the above-mentioned sound collection element and the wind-proof sound-transmitting member by a certain distance.

[0007] The sound collection element is arranged inside the housing, which can prevent the sound collection element from being directly impacted by external airflows and isolate wind noise. On this basis, after the wind-proof sound-transmitting member is arranged in the sound propagation channel, it can prevent the oil and dirt in the airflows from contaminating the sound collection element. In particular, it can effectively isolate wind noise. Even if a small amount of airflows enter the sound propagation channel, the pressure pulsation can be weakened in the wind-proof sound-transmitting member, thereby reducing the impact on the sound collection accuracy of the microphone. The oil-proof sound-transmitting membrane can effectively isolate oil and dirt and prevent the oil and dirt from entering the position where the sound collection element is located. A certain distance is set between the oil-proof sound-transmitting membrane and the sound collection element, and also between the oil-proof sound-transmitting membrane and the wind-proof sound-transmitting member. That is, the sound collection element does not contact the oil-proof sound-transmitting membrane, avoiding the variation of sound propagation caused by the vibration or micro-deformation of the oil-proof sound-transmitting membrane contacting the sound collection element and affecting the accuracy of sound collection. The wind-proof sound-transmitting member also does not contact the oil-proof sound-transmitting membrane, reducing the adhesion of oil and dirt to the oil-proof sound-transmitting membrane and prolonging the service life of the oil-proof sound-transmitting membrane.

[0008] As an improvement, the sound propagation channel includes a first channel section and a second channel section connected in sequence. The first channel section has a first sound inlet communicating with the second channel section. The sound collection element is located in the first channel section. The oil-proof sound-transmitting membrane is arranged in the first channel section and is spaced apart from the sound collection element by a certain distance. The second channel section has a second sound inlet for external sound to enter. The wind-proof sound-transmitting member is arranged in the second channel section and does not contact the oil-proof sound-transmitting membrane.

[0009] The first channel section is arranged at an angle to the second channel section, which makes the entire path of the noise in the air duct entering the second channel section from the second sound inlet and then propagating to the position of the sound collection element in the first channel section a turning path. This turning path can prevent excessive oil stains from directly passing through the sound propagation channel and contacting the sound collection element. Instead, most of the oil stains adhere to the side wall of the second channel section or the windproof sound-permeable member, so that the sound collection element can be as far away from the oil stains as possible, extending the service life of the sound collection element. On the other hand, considering that the target noise (mainly from the fan system) that the active noise reduction system needs to collect is low-frequency noise, the sound propagation path in the sound collection device adopts a turning path design, which has a weakening effect on high-frequency sounds (such as the high-frequency sound part of the 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 conducive to the accurate collection of the sound collection element. 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 curved pipeline, due to its longer wavelength, it is not easily blocked and reflected by the pipeline, so it can better propagate and spread. The wavelength of high-frequency noise is shorter, and 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 than low-frequency noise.

[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 section 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 "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 of the range 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 (such as an inclination angle of 0-30°) relative to the extension direction of the air duct.

[0013] Considering that the noise in the air duct (mainly from the fan system) propagates along the extension direction of the air duct, and the propagation direction is opposite to the air flow direction in the air duct. Therefore, the second channel section is arranged along the extension direction of the air duct, and the second sound inlet of the second channel section faces the sound source, so as to directly receive the noise in the air duct. On the other hand, considering that a windproof and sound-permeable component with a sufficient length needs to be provided on the second channel section to prevent wind noise and reduce the influence of the air duct air flow on sound collection, in the present invention, the second channel section is arranged in the extension direction of the air duct. Therefore, the size of the entire sound collection device in the direction perpendicular to the extension direction of the air duct can be made smaller, that is, it occupies less space in the air duct of the range hood, and further makes the air resistance at the position where the sound collection device in the air duct is smaller, so that 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.

[0014] Generally speaking, in order to minimize the contamination of the sound collection element in the first channel section by oil stains as much as possible, the orientation of the first sound inlet should be avoided to be the same as the extension direction of the second channel section, that is, the opening direction of the first sound inlet and the extension direction of the second channel section should preferably be set at an angle. However, the angle formed between the orientation of the first sound inlet and the extension direction of the second channel section also needs to be reasonably designed. For example, if the angle formed between the orientation of the first sound inlet and the extension direction of the second channel section is too small, the oil liquid will still enter the first channel section through the first sound inlet and contaminate the sound collection element. If the angle formed between the orientation of the first sound inlet and the extension direction of the second channel section is too large, the sound propagation path will turn too much, which will have an adverse impact 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, preferably, the extension line of the opening direction of the first sound inlet is perpendicular to the extension direction of the second channel section.

[0015] 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 the sound collection element, the housing is preferably designed with a split structure assembled by fasteners. Specifically, the housing includes a mounting frame and a windproof cover. 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 windproof cover covers outside 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 windproof cover and the mounting frame. The sound collection channel constitutes the second channel section.

[0016] As an improvement, the oil-proof sound-transmitting membrane is disposed adjacent to the first sound inlet, and the wind-proof sound-transmitting member is located on the front side of the first sound inlet. Since the turning joint position between the first channel section and the second channel section is at the first sound inlet position, disposing the oil-proof sound-transmitting membrane adjacent to the first sound inlet can directly prevent oil stains from entering the first channel section.

[0017] The "front" in the above "the wind-proof sound-transmitting member is located in front of the oil-proof sound-transmitting membrane" is not limited to the front-back direction in the actual installation environment of the range hood or the air duct, but should be understood as: the position where the wind-proof sound-transmitting member is located is also closer to the sound collection channel relative to the position where the oil-proof sound-transmitting membrane is located. For example, when the sound collection device in the present invention is installed on the left side wall of the air duct, the "the oil-proof sound-transmitting membrane is located in front of the sound collection element" at this time should be understood as: the oil-proof sound-transmitting membrane is more to the right relative to the sound collection element, that is, closer to the sound collection channel.

[0018] The setting of the wind shield can prevent the sound collection element from being directly impacted by the air flow in the air duct and isolate the wind noise. On this basis, after the wind-proof sound-transmitting member is arranged in the sound collection channel, it can prevent the oil stains in the air flow from contaminating the sound collection element. In particular, it can effectively isolate the wind noise. Even if a small amount of air flow enters the sound collection channel, the pressure pulsation can be weakened in the wind-proof sound-transmitting member, thereby reducing the impact on the sound collection accuracy of the microphone. There is also a certain distance between the oil-proof sound-transmitting membrane and the sound collection element, and between the oil-proof sound-transmitting membrane and the wind-proof sound-transmitting member. That is, the sound collection element does not contact the oil-proof sound-transmitting membrane, avoiding the variation of sound transmission caused by the vibration or micro-deformation of the oil-proof sound-transmitting membrane contacting the sound collection element and affecting the accuracy of sound collection. The wind-proof sound-transmitting member also does not contact the oil-proof sound-transmitting membrane, reducing the attachment of oil stains to the oil-proof sound-transmitting membrane and prolonging the service life of the oil-proof sound-transmitting membrane.

[0019] Considering that there may be differences in the relative front-back positions of the oil-proof sound-transmitting membrane during the installation process, in order to avoid the adverse effects caused by installation errors, the distance between the oil-proof sound-transmitting membrane and the sound collection element cannot be too small. If the distance between the two is too small, the oil-proof sound-transmitting membrane may contact the sound collection element, affecting the sound collection accuracy of the sound collection element. At the same time, in order to make the front-back size of the sound collection device as small as possible and avoid affecting the air flow stability in the air duct, the distance between the oil-proof sound-transmitting membrane and the sound collection element needs to be reasonably designed. Specifically, there is a fourth distance between the oil-proof sound-transmitting membrane and the sound collection element, and this fourth distance is denoted as f. Among them, the value range of f is: 3≥f≥0.5mm. Preferably, 3mm≥f≥2mm.

[0020] Also considering that there may be differences in the relative positions of the front and rear of the oil-proof sound-transmitting film during the installation process, in order to avoid the adverse effects caused by installation errors, the distance between the oil-proof sound-transmitting film and the wind-proof sound-transmitting member cannot be too small. If the distance between the two is too small, the oil-proof sound-transmitting film may come into contact with the wind-proof sound-transmitting member, which will affect the sound transmission effect here. At the same time, in order to make the front and rear dimensions of the sound collection device as small as possible and avoid affecting the stability of the air flow in the air duct, the distance between the oil-proof sound-transmitting film and the sound collection element needs to be reasonably designed. Specifically, the oil-proof sound-transmitting film and the wind-proof sound-transmitting member have a sixth distance in the front-rear direction, which is denoted as n. Among them, the value range of n is: 3≥n≥0.5mm.

[0021] To facilitate the installation of the oil-proof sound-transmitting film, the receiving groove is arranged in a stepped shape with a larger front and a smaller rear, and an annular step portion is formed on the side wall, and the outer peripheral edge of the oil-proof sound-transmitting film is arranged on the annular step portion. The outer peripheral edge of the oil-proof sound-transmitting film can be adhesively installed on the annular step portion to ensure the reliability and sealing of the installation of the oil-proof sound-transmitting film. On the other hand, the receiving groove is arranged in a stepped shape with a larger front and a smaller rear, which also enables the target noise to enter the receiving groove more smoothly from the sound collection channel, reducing the problem of sound pressure loss caused by too large a turning angle during the sound propagation process and improving the accuracy of sound collection. At the same time, after the relative position of the annular step portion in the receiving groove is determined, after the oil-proof sound-transmitting film is adhesively installed on the above-mentioned annular step portion, it naturally can also ensure that the distances between the oil-proof sound-transmitting film and the wind-proof sound-transmitting member and the sound collection element meet the corresponding dimensional requirements, improving the installation efficiency.

[0022] As an improvement, the sound collection channel is located on the front side of the receiving groove, and the receiving groove has a first sound inlet communicating with the sound collection channel, and the opening direction of the first sound inlet is perpendicular to the extension direction of the sound collection channel. The above structural design makes the entire path of the noise in the air duct entering the sound collection channel from the second sound inlet and then propagating to the position of the sound collection element in the receiving groove a turning path. This turning path can prevent too much oil stain from directly passing through the sound collection channel and contacting the sound collection element, but make most of the oil stain adhere to the side wall of the sound collection channel or the wind-proof sound-transmitting member. As a result, the sound collection element can be as far away from the oil stain as possible, extending the service life of the sound collection element. On the other hand, the sound propagation path in the sound collection device adopts a turning path design, which has a weakening effect on high-frequency sounds (such as the high-frequency sound part in wind noise and the high-frequency sound components generated by the fan system, etc., non-target noises), and has little impact on low-frequency sounds. Therefore, it can be better applied to the propagation of low-frequency noises in the sound collection device, facilitating the accurate collection of the sound collection element.

[0023] As an improvement, the extending direction of the sound collection channel is the same as that of the air duct. Along the direction of the air flow channel in the air duct, a second sound inlet communicating with the sound collection channel is defined between the windward end of the wind shield and the mounting bracket. Considering that the noise in the air duct (mainly from the fan system) propagates along the extending direction of the air duct and the propagation direction is opposite to the air flow direction in the air duct, therefore, arranging the sound collection channel along the extending direction of the air duct and forming the structure of the second sound inlet at the windward end of the wind shield can make the second sound inlet of the sound collection channel face the sound source so as to directly receive the noise in the air duct. On the other hand, according to the air flow law, since the second sound inlet is located at the windward end of the wind shield, a low-speed and high-static-pressure area is formed in the air duct adjacent to the second sound inlet. 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 receiving groove of the mounting bracket through the above-mentioned second sound inlet, ensuring the accuracy of noise data collection.

[0024] Considering that the extending direction of the air duct is mostly vertical, for adaptation, the sound collection channel is arranged to extend vertically, and the opening direction of the second sound inlet is upward.

[0025] As an improvement, the oil-proof sound-permeable film is a polyethylene film, and the wind-proof sound-permeable member is a sound-permeable member made of a porous sound-absorbing material. Using a polyethylene film can ensure the oil-proof performance of the oil-proof sound-permeable film, extend the service life, and enable it to effectively transmit sound waves. Using a sound-permeable member made of a damping material such as a porous sound-absorbing material as the wind-proof 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 wind-proof sound-permeable member can be made of polyurethane foam, melamine foam sponge, etc. The wind-proof sound-permeable member can not only prevent the air flow from impacting the oil-proof sound-permeable film to generate additional noise, but also absorb the high-frequency components in the sound energy due to its porous material property, realizing the function of filtering the noise signal.

[0026] The technical solution adopted by the present utility model to solve the second technical problem is: The technical solution adopted by the present invention to solve the second technical problem is: An oil fume extractor includes an air duct for flue gas to pass through and a sound collection device arranged in the air duct, and the sound collection device adopts the above-mentioned sound collection device.

[0027] As an improvement, the sound collection element is a microphone.

[0028] Compared with the prior art, the advantages of the present utility model are:

[0029] First, the sound collection component is disposed within the housing, which can prevent the sound collection component from being directly impacted by external airflows and isolate wind noise. On this basis, after a windproof sound-permeable component is arranged in the sound propagation channel, it can prevent the oil stains in the airflows from contaminating the sound collection component. In particular, it can effectively isolate wind noise. Even if a small amount of airflows enter the sound propagation channel, the pressure pulsation can be weakened in the windproof sound-permeable component, thereby reducing the impact on the accuracy of the microphone's sound collection.

[0030] Secondly, the oil-proof sound-permeable membrane can effectively isolate oil stains and prevent them from entering the position where the sound collection component is located. A certain distance is set between the oil-proof sound-permeable membrane and the sound collection component, as well as between the oil-proof sound-permeable membrane and the windproof sound-permeable component. That is to say, the sound collection component does not contact the oil-proof sound-permeable membrane, avoiding sound propagation variation caused by the vibration or micro-deformation of the oil-proof sound-permeable membrane contacting the sound collection component and affecting the accuracy of sound collection. The windproof sound-permeable component also does not contact the oil-proof sound-permeable membrane, reducing the attachment of oil stains to the oil-proof sound-permeable membrane and prolonging the service life of the oil-proof sound-permeable membrane.

[0031] Furthermore, in the preferred solution, the sound propagation channel is designed with a structure in which the first channel section and the second channel section are arranged at an angle. The entire path of the noise in the air duct from the second sound inlet entering the second channel section and then propagating to the position of the sound collection component in the first channel section is a turning path. This turning path can prevent excessive oil stains from directly passing through the sound propagation channel and contacting the sound collection component. Instead, most of the oil stains adhere to the side wall of the corresponding channel section or the windproof sound-permeable component. Thus, the sound collection component can be as far away from the oil stains as possible, prolonging the service life of the sound collection component. On the other hand, 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 part in wind noise and the high-frequency sound components generated by the fan system, etc., which are non-target noises), and has less impact on low-frequency sounds. Therefore, it can be better applied to the propagation of low-frequency noises in the sound collection device, facilitating the accurate collection of low-frequency noises by the sound collection component. Description of the Drawings

[0032] Figure 1 is a three-dimensional structural schematic diagram of the sound collection device according to Embodiment 1 of the present utility model;

[0033] Figure 2 is an exploded view of the sound collection device according to Embodiment 1 of the present utility model;

[0034] Figure 3 is a vertical cross-sectional view of the sound collection device according to Embodiment 1 of the present utility model cut along the front-back direction;

[0035] Figure 4 is Figure 3 a structural schematic diagram after omitting the windproof sound-permeable component in

[0036] Figure 5 is a cross-sectional view taken along the Figure 3 A-A direction in the middle;

[0037] Figure 6 is a three-dimensional structural schematic diagram of the sound collection device according to Embodiment 1 of the present utility model installed in the air duct;

[0038] Figure 7 is Figure 6 a transverse cross-sectional view taken along the front-rear direction;

[0039] Figure 8 is a schematic diagram of the sound propagation process at the first sound inlet of the mounting bracket. Detailed implementation manners

[0040] The present utility model will be further described in detail below in conjunction with the embodiments with reference to the drawings.

[0041] In the description and claims of the present utility model, terms indicating directions 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 utility model. However, these terms are used here only for the convenience of description and are determined based on the exemplary orientations shown in the drawings. Since the embodiments disclosed by the present utility model can be arranged in different directions, these terms indicating directions are 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.

[0042] Figures 1-7 shows a preferred embodiment of the sound collection device and the range hood of the present invention.

[0043] 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 section and a second channel section connected in sequence. Among them, 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 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 section and the second channel section are straight channels. Among them, the extension line of the first channel section intersects with the extension line of the second channel section. The extension line of the first channel section can be understood as the connection line between the position where the sound inlet of this channel section is located and the position where the sound collection element 11 is located. The extension line of the second channel section can be understood as the connection line between the position where the sound inlet of this channel section is located and the position where the sound outlet is located.

[0044] The active noise reduction system is usually arranged in the air duct 10 of an oil fume extraction device (such as a range hood or an integrated stove with an oil fume extraction 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 extraction 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.

[0045] 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-transmitting membrane 28 and a wind-proof sound-transmitting member 30. The housing includes a mounting frame 20 and a wind-proof cover 40.

[0046] In this embodiment, taking the box 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. The channel in the box 1 serves as the air duct 10. The mounting frame 20 can be installed on the rear side wall of the air duct 10, and it has a receiving groove 21 for placing the sound collection element 11, 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 sound collection channel 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 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 open mouth at the front part of the receiving groove 21. In the state where the mounting frame 20 is installed in place on the rear side wall of the air duct 10, the rear wall of the part of the mounting frame 20 where the receiving groove 21 is located is attached to the rear side wall of the air duct 10.

[0047] The mounting bracket 20 further has a third mounting portion 263 that extends respectively to the left and right sides and exposes outside the wind shield 40, and a fourth mounting portion 264 that extends downward at the bottom of the mounting bracket 20 and exposes 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. At the lower region of the receiving groove 21 of the mounting bracket 20, there is a connecting column 265 that extends forward. The wind shield 40 can be connected to the connecting column 265 of the mounting bracket 20 by screws 50.

[0048] 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 that is 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 direction of the air flow in the air duct 10 (such as Figure 3 the direction indicated by the hollow arrow in the figure). 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. The upper part of the third side wall 413 is basically arranged to extend vertically 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 direction of the air flow 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 at the position in the wind shield 40 opposite to the front part of the receiving groove 21 to arrange components such as the wind-proof and sound-permeable member 30 and the oil-proof and sound-permeable film 28. 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 air flow 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 installing 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 installing 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 in the air flow 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, see Figure 7 .

[0049] To improve the anti-oil pollution effect, the wind shield 40 of this embodiment can be made of plastic or metal parts.

[0050] In this embodiment, a gap channel extending vertically is formed between the front side surface of the wind shield 40 and the mounting bracket 20 in the front-rear direction. 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 bracket 20, that is, it constitutes the second channel section of the above-mentioned housing 2. Specifically, a second sound inlet 45 communicating with the above-mentioned sound collection channel 200 is defined between the windward end 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 bracket 20. The air duct 10 of this embodiment also extends 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 B1 of the first sound inlet 211 intersects with the extension direction B3 of the sound collection channel 200 to form a first included angle. Considering that if the included 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 included 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, and it is not conducive to the accurate collection of noise by the sound collection element. Therefore, the first included angle formed between the orientation B1 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 included angle is: 5° < M < 180°. More preferably, the value of the first included 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.

[0051] 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 retained, directly isolating the lower airflow noise and the noise interference of the secondary turbulence, 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 relatively 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.

[0052] Since the sound collection element 11 is installed in the accommodation groove 21 of the mounting bracket 20 and a windproof cover 40 is provided outside the mounting bracket 20, the interference of the airflow in the air duct 10 to the sound collection element 11 can be effectively isolated, and the sound collection element 11 can be prevented from being polluted by the oil stain in the airflow. 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 a windproof and sound-permeable member 30 with a sufficient length needs to be provided 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 of the sound collection device 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 reduce 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 the same as the extension direction B3 of the sound collection channel 200, that is, the opening direction B1 of the first sound inlet 211 faces upward, then the sound collection element 11 is easily polluted by the oil stain flowing down along the air duct 10. Therefore, in this embodiment, the opening direction B1 of the first sound inlet 211 of the accommodation groove 21 and the extension direction B3 of the sound collection channel 200 are set at a certain angle, preferably a vertical design. This makes the entire sound propagation path from the noise in the air duct 10 entering the sound collection channel 200 through the second sound inlet 45 and then propagating to the position of the sound collection element 11 in the accommodation 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 make most of the oil stain 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 stain 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 curved 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.

[0053] The oil-proof sound-permeable membrane 28 covers the first sound inlet 211 of the accommodation groove 21 of the mounting frame 20. 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. The wind-proof sound-permeable member 30 is a laminated structure with a uniform thickness, which is arranged in the sound collection channel 200 and is located on the front side of the oil-proof sound-permeable membrane 28.

[0054] 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, f should be greater than 0.1 mm, and the preferred value range is: 3 mm ≥ f ≥ 0.5 mm. More preferably, 3 ≥ f ≥ 2 mm. Thus, it is avoided that the film vibrates or undergoes micro-deformation and contacts the sound collection element 11, resulting in sound propagation variation and affecting the accuracy of sound collection. It can be understood that the above-mentioned fourth distance f between the 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. The wind-proof sound-permeable member 30 in this embodiment does not contact the oil-proof sound-permeable membrane 28, reducing the attachment of oil stains to the oil-proof sound-permeable membrane 28 and extending the service life of the oil-proof sound-permeable membrane 28. Specifically, there is a sixth distance between the main body of the oil-proof sound-permeable membrane 28 and the wind-proof sound-permeable member 30 in the front-rear direction, which is denoted as n, and n should be greater than 0.1 mm. The preferred value range of n is: 3 mm ≥ n ≥ 0.5 mm. More preferably, 3 ≥ n ≥ 2 mm.

[0055] More specifically, the receiving groove 21 is arranged in a stepped shape with a larger front and a smaller rear, and an annular stepped portion 210 is formed on the side wall. The outer peripheral edge of the oil-proof sound-transmitting film 28 is arranged on the annular stepped portion 210, thereby ensuring the reliability and sealing of the installation of the oil-proof sound-transmitting film 28 and improving the oil-proof effect. On the other hand, the receiving groove 21 in this embodiment is arranged in a stepped shape with a larger front and a smaller rear, which also enables the target noise to enter the receiving groove 21 more smoothly from the sound collection channel 200, reducing the problem of sound pressure loss caused by too large a turning angle during the sound propagation process and improving the accuracy of sound collection. At the same time, after the relative position of the annular stepped portion 210 in the receiving groove 21 is determined, directly pasting and installing the oil-proof sound-transmitting film 28 on the above-mentioned annular stepped portion 210 can naturally ensure that the distance between the oil-proof sound-transmitting film 28, the wind-proof sound-transmitting member 30, and the sound collection element 11 meets the corresponding dimensional requirements, improving the installation efficiency.

[0056] In order to effectively slow down the airflow and eliminate the airflow impact, the wind-proof sound-transmitting member 30 is a sleeve member made of a porous sound-absorbing material. For example, the wind-proof sound-transmitting member 30 can be made of polyurethane foam, melamine foam sponge, etc. Among them, the porosity of the wind-proof sound-transmitting member 30 is greater than 70%. The wind-proof sound-transmitting member 30 in this embodiment can not only prevent the airflow from impacting the oil-proof sound-transmitting 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, realizing the filtering function of filtering the noise signal. More specifically, the front side wall of the wind-proof sound-transmitting member 30 is attached to the rear side wall of the third side wall 413 of the wind-proof cover 40, so that the wind-proof sound-transmitting member 30 is in a compressed state. By compression, the material density can be increased, effectively reducing the possibility of the penetration of the airflow pressure pulsation, thereby further improving the wind-proof effect.

[0057] The windproof sound-transmitting 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. The length of the extension section 301 of the windproof sound-transmitting member 30 is denoted as h, and the dimension 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 to 0.6. Since the sound collection channel 200 is arranged at an angle to the opening direction of the first sound inlet 211, that is, there is a turning part at the first sound inlet 211 of the accommodation groove 21. If the length of the outward extension of the outer peripheral edge part of the windproof sound-transmitting member 30 relative to the edge of the first sound inlet 211 of the accommodation groove 21 is too short (such as h / m being 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-transmitting member 30 is effectively guaranteed, and the influence on the accuracy of sound collection caused by the too short outward extension length of the outer peripheral edge of the windproof sound-transmitting member 30 is avoided. Of course, considering the adverse effect of the windproof sound-transmitting member 30 on sound attenuation, the length dimension of the extension section 301 of the windproof sound-transmitting 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, reducing the accuracy of noise collection.

[0058] To avoid the windproof and sound-permeable component 30 coming into contact with the oil flowing continuously down the side wall of the air duct 10, after being installed on the mounting bracket 20, there is a first spacing between the windproof and sound-permeable component 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 and sound-permeable component 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 and sound-permeable component 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 and sound-permeable component 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 and sound-permeable component 30 in the front-rear direction is fixed, the dimension d1 of the main body of the windproof and sound-permeable component 30 in the left-right direction also needs to be adapted to it, that is, it is necessary to reasonably limit e / d1. In this embodiment, the value range of e / d1 is: 0.2 - 0.5. 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 and sound-permeable component 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 and sound-permeable component 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 and sound-permeable component 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 angular range in the horizontal direction above, affecting the accuracy of sound collection.

[0059] Due to the setting of the windproof and sound-permeable component 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 accommodation groove 21 of the mounting bracket 20 to be received by the sound collection element 11 and achieve the purpose of accurately collecting noise signals. Specifically, the principles of sound attenuation and compensation are as follows:

[0060] L w =L1 - ΔL + 10lgS0

[0061] Among them, the noise energy that the sound collection component can collect per unit time is the sound power L w ;

[0062] The sound pressure when the sound reaches the top surface of the windproof and sound-permeable component 30 is L1;

[0063] Due to the attenuation effect of the windproof and sound-permeable component 30, the lost noise sound pressure is ΔL;

[0064] The area S0 of the cross-section at the second sound inlet 45 of the sound collection channel 200;

[0065] Therefore, if the sound is severely attenuated due to the excessive thickness or the length dimension in the sound propagation path of the windproof sound-permeable member 30, the sound power L collected by the sound collection element can be ensured by increasing S0. 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 in this embodiment to the opening area S at 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, which can ensure that enough noise can pass through the sound collection channel 200 of the sound collection device, compensate for the sound pressure loss caused by the setting of the windproof sound-permeable member 30, and further ensure that the sound can meet the sound pressure requirements of the sound collection element 11 when it propagates to the second sound inlet 45, further improving the accuracy of noise collection.

[0066] On the other hand, the dimension of the main body of the windproof sound-permeable member 30 in the up-down direction in this embodiment is denoted as l. In order to adapt to the dimension of the first sound inlet 211 at the front part of the accommodation groove and ensure the windproof effect, 100mm≥l≥10mm. The cross-sectional area of the main body of the windproof sound-permeable 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-permeable 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 11. 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)≤10, it means that the inlet area for the sound to effectively pass from top to bottom at the end position of the windproof sound-permeable 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-permeable 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 pass from top to bottom at the end position of the windproof sound-permeable member 30 near the second sound inlet 45 is large. Similarly, the area of the upper part of the windproof sound-permeable member 30 in contact with the oil stain increases, affecting the service life of the windproof sound-permeable member 30.

[0067] In the present embodiment, since the windproof and sound-permeable member 30 is filled in the sound collecting channel 200, that is, there is no gap between the front side of the windproof and sound-permeable member 30 and the wind shield 40, the cross-sectional area S1 of the main body of the windproof and sound-permeable member 30 adjacent to the second sound inlet 45 is substantially consistent with the cross-sectional area S0 of the second sound inlet 45 of the sound collecting channel 200.

[0068] The area of ​​the cross section formed by cutting the windproof sound-permeable member 30 in the extension direction of the sound collecting channel 200 (i.e., the cross section cut vertically along the left-right direction) of this embodiment is recorded as S3, and the opening area of ​​the first sound inlet 211 at the front of the receiving groove 21 of the mounting frame 20 is recorded as S, where S 3 / The value range of S is: 13.5≥S3 / S≥1.5. If S3 / S is too small (such as less than 1.5), it means that the size of the windproof sound-permeable component 30 is small, and the area of ​​the first sound inlet 211 of the receiving slot 21 is too large, the windproof effect is not good, and the accuracy of sound collection will be affected; if S3 / S is too large (such as greater than 13.5), it means that the size of the windproof sound-permeable component 30 is large, and the area of ​​the first sound inlet 211 of the receiving slot 21 is too small, which will cause more sound loss when passing through the windproof sound-permeable component 30, and it is difficult for the sound to meet the sound pressure requirement of the sound collection element 11 when the sound is transmitted to the receiving slot 211. Since the windproof sound-permeable member 30 is provided in the sound collection channel 200, it will have an adverse effect on the sound propagation, that is, it will lose a part of the sound pressure. Therefore, the size of the windproof sound-permeable member 30 cannot be designed to be too large. Of course, in order to ensure the windproof performance of the windproof sound-permeable member 30 and ensure that the airflow pressure pulsation does not affect the sound collection element 11, the size of the windproof sound-permeable member 30 cannot be designed to be too small. For this reason, on the basis of ensuring that the windproof sound-permeable member 30 covers the first sound inlet 211 of the receiving groove 21, the windproof sound-permeable member 30 is extended in the direction of the sound collection channel 200. The ratio of the area S3 of the cross section formed by cutting upward to the opening area S at the first sound entrance 211 at the front of the receiving groove 21 needs to be limited to the above-mentioned reasonable value range (13.5≥S3 / S≥1.5). In this way, it can ensure that the windproof and sound-permeable component 30 has a relatively good windproof effect, while avoiding the loss of sound when passing through the windproof and sound-permeable component 30 due to the excessive size of the windproof and sound-permeable component 30. This ensures that the sound pressure requirement of the sound collecting element 11 can be met when the sound is propagated to the receiving groove, thereby improving the accuracy of noise collection.

[0069] The cross section of the windproof and sound-permeable member 30 of this embodiment cut along the extension direction of the sound collecting channel 200 is a rectangle, so S3 = d1*l.

[0070] The protective structure of this embodiment can realize the sound collection element to suppress wind noise while also ensuring that the noise signal passes through. According to the sound propagation theory, the protective structure consists of a sound mass M aHarmonic content C a forms a low-pass filter. Therefore, it is necessary to make the cut-off frequency f of the structure itself c greater than the upper limit frequency f a of the active noise cancellation concerned, so as to accurately collect all the original noise frequencies concerned by the active noise cancellation.

[0071] Wherein:

[0072]

[0073] V is the volume of the cavity in the protection structure, specifically the volume of the inner cavity formed by the oil-proof sound-transmitting 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;

[0074] S0 is the effective area of sound propagation in the pipeline, and can be simplified to take the minimum cross-sectional area of the pipeline during the sound propagation process. In this embodiment, S0 is the area of the cross-section at the second sound inlet 45 of the sound collection channel 200;

[0075]

[0076] 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 limit frequency f a concerned by the active noise cancellation of the range hood, it should be 1200-2000 Hz. Therefore, it can be obtained that:

[0077]

[0078] After simplification, it is:

[0079]

[0080] The protection structure of this embodiment must meet the requirements of the above formula.

[0081] More specifically, in this embodiment, S0 is the area of the cross-section at the second sound inlet 45 of the sound collection channel 200, wherein the second sound inlet 45 is a strip-shaped opening. Therefore:

[0082] S0 = ed;

[0083] L is the path length of sound propagation. Since the sound collection channel 200 in this embodiment is not a regular pipeline, it can be simplified as:

[0084]

[0085] Among them, the dimension of the wind-proof sound-transmitting member 30 in the up and down direction is denoted as g, and the dimension (i.e., thickness) of the main body of the wind-proof sound-transmitting member 30 in the front and back direction is denoted as e,

[0086] The above-mentioned

[0087] Further simplified to get:

[0088]

[0089] After the sound collection element 11 of this embodiment is installed in the accommodation groove 21 of the mounting bracket 20, an oil-proof sound-transmitting membrane 28 is provided at its first sound inlet 211, a wind-proof sound-transmitting member 30 is provided outside it, 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 airflow movement 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 (that is, the noise of the fan system) can be effectively transmitted to the accommodation groove 21 of the mounting bracket 20 through the above-mentioned 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.

[0090] This embodiment also relates to a range hood, including a flue 10 for the flue gas to pass through 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 arranged in the accommodation 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.

Claims

1. A sound collection device, comprising a sound collection element (11), characterized in that: It further includes a housing (2), the sound collection element (11) is arranged inside the housing (2), a sound propagation channel for external sound to be transmitted to the position of the sound collection element (11) is defined on the housing (2), an oil-proof sound-permeable membrane (28) and a wind-proof sound-permeable member (30) are also arranged in the sound propagation channel, along the extension direction of the sound propagation channel, the above-mentioned oil-proof sound-permeable membrane (28) is arranged adjacent to the sound collection element (11) relative to the wind-proof sound-permeable member (30), and is spaced from both the above-mentioned sound collection element (11) and the wind-proof sound-permeable member (30) by a certain distance.

2. The sound collection device according to claim 1, wherein: The sound propagation channel includes a first channel segment and a second channel segment connected in sequence. The first channel segment has a first sound inlet (211) communicating with the second channel segment. The sound collection element (11) is located in the first channel segment. The oil-proof sound-permeable membrane is arranged in the first channel segment and is spaced from the sound collection element (11) by a certain distance. The second channel segment has a second sound inlet (45) for external sound to enter. The wind-proof sound-permeable member (30) is arranged in the second channel segment and does not contact the oil-proof sound-permeable membrane (28).

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

4. The sound collection device according to claim 3, wherein: The extension line of the opening direction of the second sound inlet (45) is consistent with the extension direction of the air duct (10), and the extension line of the opening direction of the first sound inlet (211) is arranged at an angle with the extension direction of the second channel segment.

5. The sound collection device according to claim 4, characterized in that: The extension line of the opening direction of the first sound inlet (211) is perpendicular to the extension direction of the second channel segment.

6. The sound collection device according to any one of claims 3-5, characterized in that: The housing (2) includes a mounting bracket (20) and a wind-proof cover (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 segment. The front opening of the receiving groove (21) is the first sound inlet (211). The wind-proof cover (40) covers outside the mounting bracket (20), and a sound collection channel (200) that is connected to the first sound inlet (211) of the receiving groove (21) and is located in front of the receiving groove (21) is defined between the wind-proof cover (40) and the mounting bracket (20). The sound collection channel (200) constitutes the second channel segment. A second sound inlet (45) that is connected to the sound collection channel (200) is defined between the wind-proof cover (40) and the mounting bracket (20) at the windward end.

7. The sound collection device according to claim 6, characterized in that: The oil-proof sound-permeable membrane (28) is arranged adjacent to the first sound inlet (211), and the wind-proof sound-permeable member is located in front of the first sound inlet (211).

8. The sound collection device according to claim 6, wherein: There is a fourth spacing between the oil-proof sound-transmitting film (28) and the sound collection element (11), and this fourth spacing is denoted as f. Among them, the value range of f is: 3≥f≥0.5mm.

9. The sound collection device according to claim 8, wherein: There is a sixth spacing between the oil-proof sound-transmitting film (28) and the wind-proof sound-transmitting member (30) in the front-rear direction, and this sixth spacing is denoted as n. Among them, the value range of n is: 3≥n≥0.5mm.

10. The sound collection device according to claim 7, wherein: The accommodation groove (21) is arranged in a stepped shape with a larger front and a smaller rear, and an annular stepped portion (210) is formed on the side wall. The outer peripheral edge of the oil-proof sound-transmitting film (28) is arranged on the annular stepped portion (210).

11. The sound collection device according to claim 6, wherein: The sound collection channel (200) is arranged to extend vertically, and the opening direction of the second sound inlet (45) is upward.

12. The sound collection device according to any one of claims 1 to 5, characterized in that: The oil-proof sound-transmitting film (28) is a polyethylene film, and the wind-proof sound-transmitting member (30) is a sound-transmitting member made of a porous sound-absorbing material.

13. An oil fume suction machine, comprising an air duct (10) for the passage of flue gas and a sound collection device arranged in the air duct (10), characterized in that: The described sound collection device adopts the sound collection device described in any one of claims 1 to 12.

14. The range hood according to claim 13, wherein: The described sound collection element (11) is a microphone.

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