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, the sound transmission channel comprises a first channel section and a second channel section, and the first channel section and the second channel section are connected in sequence and arranged at an included angle. The sound collection element is located in the first 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, a windproof sound transmission part is further arranged in the second channel section, the area of the first sound inlet is recorded as S, and the area of the second sound inlet is recorded as S; the area of the second sound inlet is recorded as S0, and the value range of S0 / S is that S0 / S is greater than or equal to 0.18. 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 problem of range hoods has always been one of the main problems troubling users. Active noise reduction, as a new type of noise reduction technology, has also been considered for application on range hoods for noise reduction. An 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 is: CN111928310A) discloses such a range hood with an active noise reduction function. The microphone of this range hood is arranged inside 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] In order 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 oil and grease environment of the range hood, the microphones and speakers are often contaminated, resulting in the reduction of the noise reduction effect of the active noise reduction system as the use time increases, 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-proof device, including an incoming device, a central data processor, and a noise reduction unit. The incoming device includes a microphone, and the microphone is arbitrarily installed at a place of the range hood. The noise reduction unit includes at least two noise reduction boxes, and the noise reduction boxes are arranged at the bottom of the volute of the range hood, facing the air inlet. An oil-proof device is arranged below the noise reduction box, and the oil-proof device is also arranged at the bottom of the volute and covers the noise reduction box. The oil-proof 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. The microphone and the noise reduction speaker are both connected to the central data processor. The central data processor loads a self-check module and an oil contamination detection module for the noise reduction device. The oil contamination detection module detects the oil contamination of the oil-proof 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.

[0004] However, the oil-proof device of the active noise reduction device of the above-mentioned patent application still has certain deficiencies. The oil-proof device achieves sound transmission and oil prevention through a porous sound-permeable shell and an oil-proof film attached to the surface of the porous sound-permeable shell. The influence of wind noise in the air duct of the range hood is not taken into consideration, that is, no effective wind noise prevention treatment is performed. On the other hand, if the porous sound-permeable shell set above has a large number of openings, it will have an adverse effect on oil and wind prevention. If the number of openings is small, the noise will be lost more during the propagation process, resulting in the accuracy of sound collection being affected. Therefore, how to provide a sound collection device that can effectively prevent oil and achieve the purpose of wind noise prevention, thereby ensuring the accuracy of sound collection has become a technical problem that needs to be urgently solved by those skilled in the art. Summary of the Invention

[0005] The first technical problem to be solved by the present invention is to provide a sound collection device that can achieve the purpose of oil and wind protection and can fully collect target noise signals, thereby ensuring the accuracy of sound collection, based on the current status of the existing technology.

[0006] The second technical problem to be solved by the present invention is to provide a range hood using the above-mentioned sound collection device in view of the current status of the existing technology.

[0007] The technical solution adopted by the present invention to solve the first technical problem mentioned above is: a sound collecting device, including a sound collecting element and a shell, the shell defining a sound propagation channel, the sound propagation channel including a first channel section and a second channel section connected in sequence and arranged at an angle, the sound collecting element is located in the first channel section, the first channel section has a first sound inlet connected to the second channel section, the second channel section has a second sound inlet for external sound to enter, and the second channel section is also provided with a windproof and sound-permeable component, the area at the above-mentioned first sound inlet is denoted as S, the area at the second sound inlet is denoted as S0, and the value range of S0 / S is: S0 / S≥0.18.

[0008] The sound propagation channel of the sound collection device is designed as a first channel section and a second channel section arranged at an angle, and the sound collection element is placed in the first channel section of the sound collection device, which can effectively isolate the interference of the airflow in the air duct to the sound collection element and prevent the oil stain in the airflow from contaminating the sound collection element. At the same time, a windproof sound-permeable component is arranged in the second channel section of the housing, which can effectively eliminate wind noise. Even if a small amount of airflow enters the sound collection channel, the pressure pulsation can be weakened in the windproof sound-permeable component, thereby reducing the impact on the sound collection accuracy of the microphone. Considering that the air duct environment of the range hood is full of oil stains, in order to prevent the sound collection element from being contaminated by the oil stains flowing down along the air duct, therefore, in the present invention, the first channel section and the second channel section are arranged at an angle, which makes the whole 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 too much oil stain from directly passing through the sound propagation channel and contacting the sound collection element, but make most of the oil stains adhere to the side wall of the second channel section or the windproof sound-permeable component, so that the sound collection element can be as far away from the oil stains as possible and the service life of the sound collection element can be extended. On the other hand, considering that the target noise (mainly from the fan system) to be collected by the active noise reduction system is low-frequency noise, and 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 and other 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 and 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 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 and 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. Finally, because a windproof sound-permeable component is arranged in the second channel section, and the sound propagation path in the collection device is a turning path, it will have an adverse impact on sound propagation, that is, a part of the sound pressure will be lost. According to the sound propagation principle L w = L1 + 10lgS (L Wwhere \(W\) is the sound power, \(L_1\) is the sound pressure, and \(S\) is the area of the sound inlet. When the sound pressure \(L_1\) is lost, as compensation, the sound power collected by the sound collection element can be maintained by increasing the area \(S_0\) of the second sound inlet of the sound collection channel. Therefore, limiting the ratio of the area \(S_0\) of the second sound inlet of the sound collection channel to the area \(S\) of the first sound inlet of the accommodation groove within a reasonable value range (\(S_0 / S\geq0.18\)) can ensure that sufficient noise can pass through the sound propagation channel of the sound collection device to compensate for the sound pressure loss caused by the setting of the windproof sound-permeable member. Furthermore, it can ensure that when the sound propagates to the first channel section, it can meet the sound pressure requirements of the sound collection element, further improving the accuracy of noise collection.

[0009] When the second sound inlet is relatively small, such as when \(S_0 / S\lt0.18\), it cannot well ensure that sufficient noise can pass through the sound collection channel of the sound collection device to compensate for the sound pressure loss caused by the setting of the windproof sound-permeable member. In this case, the accuracy of sound collection is lower than 80%. On the other hand, if the opening area of the second sound inlet is relatively large, such as when \(S_0 / S\gt1.5\), the accuracy of sound collection basically fluctuates around 98% - 99%. In this case, the improvement in the accuracy of noise collection is small, the improvement in the active noise reduction effect is weak, but the installation space requirement for the sound collection device is larger. Therefore, the preferred value range of \(S_0 / S\) is: \(0.18\leq S_0 / S\leq1.5\).

[0010] As an improvement, when \(0.18\leq S_0 / S\lt0.3\), since the second sound inlet is relatively enlarged, the sound collection channel can be made relatively unobstructed, and the accuracy of sound collection is improved, generally reaching within the range of 80% - 88%. When \(0.3\leq S_0 / S\leq1.5\), within this range, the accuracy of noise collection is optimal, generally reaching around 91% - 98%. Moreover, the installation space requirement for the sound collection device is also relatively reasonable and will not overly occupy the space in the air duct. Therefore, the preferred value range of \(S_0 / S\) is: \(0.3\leq S_0 / S\leq1.5\).

[0011] 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 windward end of the housing. The opening direction of the second sound inlet is consistent with the extension direction of the air duct.

[0012] The above-mentioned "windward end of the housing" 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.

[0013] The above-mentioned "the second channel section is arranged along the extending direction of the air duct" can be understood as that the overall extending direction of the second channel section is the same as or parallel to the extending direction of the air duct, or it can also be understood as that the overall extending direction of the second channel section has a certain inclination angle (such as an inclination angle of 0-30°) relative to the extending direction of the air duct.

[0014] The second channel section can be a straight channel structure, or a non-straight channel structure with local bends or curves. In order to avoid adverse effects on sound propagation due to excessive turns in the sound propagation path within the sound collection device, and considering the convenience of installing components such as the windproof sound-permeable member within the second channel section, the main body of the second channel section will adopt a straight channel that is the same as the extending direction of the air duct. Generally speaking, in order to minimize the contamination of the sound collection element in the first channel section by oil stains, the orientation of the first sound inlet should be avoided to be the same as the extending direction of the second channel section, that is, the opening direction of the first sound inlet and the extending 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 extending 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 extending 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 extending direction of the second channel section is too large, the sound propagation path will have too large a turn, 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 value range of the first angle formed by the intersection of the opening direction of the first sound inlet and the extending direction of the second channel section is: 5° ≤ M ≤ 180°.

[0015] In order to better avoid the sound collection element from contacting oil stains and improve the windproof effect, both the second channel section and the extending direction of the air duct extend vertically, the opening of the second sound inlet faces upward, and the opening direction of the first sound inlet is perpendicular to the extending direction of the second channel section, that is, the first angle is a right angle.

[0016] 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 together 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. This sound collection channel constitutes the second channel section.

[0017] As an improvement, the front side wall of the windproof sound-permeable member is attached to the rear side wall of the windproof cover. The above structural design can make the windproof sound-permeable member in a compressed state. By compression, the material density can be increased, which can effectively reduce the possibility of the penetration of the airflow pressure pulsation, thereby further improving the windproof effect.

[0018] To ensure the windproof effect, the thickness of the windproof sound-permeable member (i.e., the dimension in the front-back direction) needs to be reasonably designed. At the same time, to reduce the influence of the windproof sound-permeable member on the sound propagation loss, the dimension of the part of the windproof sound-permeable member adjacent to the second sound inlet in the left-right direction also needs to be reasonably designed. Specifically, the second channel section extends vertically. The dimension of the part of the windproof sound-permeable member adjacent to the second sound inlet in the front-back direction is denoted as e, and the dimension in the left-right direction is denoted as d1. Among them, the value range of e / d1 is: 0.2 ≤ e / d1 ≤ 0.5, and the value range of e is 3 mm ≤ e ≤ 40 mm. Among them, to ensure that the windproof sound-permeable member can effectively prevent the airflow in the air duct from directly impacting the sound collection element, the dimension of the windproof sound-permeable member in the front-back direction (i.e., the thickness) needs to be e ≥ 3 mm. Of course, considering the adverse impact of the existence of the windproof sound-permeable member (generally made of porous materials that can prevent airflow disturbance and transmit sound) on sound propagation, so the dimension of the windproof sound-permeable member in the front-back direction (i.e., the thickness) cannot be too large, and it needs to be e ≤ 40 mm. At the same time, when the dimension of the windproof sound-permeable member in the front-back direction (i.e., the thickness) is certain, the dimension d1 of the main body of the windproof sound-permeable member in the left-right direction also needs to be adapted to it. If e / d1 is too small, it means that the dimension of the main body of the windproof sound-permeable member in the left-right direction is larger, and the area of its upper part in contact with the oil stain increases, affecting the service life of the windproof sound-permeable member. If e / d1 is too large, it means that the dimension of the main body of the windproof sound-permeable member in the left-right direction is smaller, which is not conducive to the sound being transmitted from the upper part to the sound collection channel within a relatively large angular range in the horizontal direction, affecting the accuracy of sound collection.

[0019] The increase in the size of the windproof sound transmission component in the up and down direction increases the windproof effect, but it also means an increase in the loss during the propagation of sound in the sound collection device. Therefore, on the basis that the size of the windproof sound transmission component in the up and down direction meets the conditions, the sound transmission area of the windproof sound transmission component should be adapted to the size range of the windproof sound transmission component in the up and down direction to ensure that enough noise to be collected enters the sound collection channel, thereby further reducing the impact of the windproof sound transmission component on the sound propagation loss. Specifically, the cross-sectional area of the main body of the windproof sound transmission component near the second sound inlet is S1, the size of the part of the windproof sound transmission component near the second sound inlet in the front and back direction is denoted as e, and the size of the main body of the windproof sound transmission component in the up and down direction is denoted as g. g / 2 + e / 2 represents the sound propagation path length in the windproof sound transmission component. 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 at the sound inlet), due to the sound loss causing the reduction of the sound pressure during the sound propagation process, 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 8 mm, and the preferred value range is: 10 mm ≤ S1 / (g / 2 + e / 2) ≤ 15 mm. 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 component 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 component on the sound loss in the up and down direction and the front and back direction, reducing the accuracy of the sound collected by the sound collection element. 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 component near the second sound inlet is large. Similarly, the area of the upper part of the windproof sound transmission component in contact with the oil stain increases, affecting the service life of the windproof sound transmission component.

[0020] As an improvement, the second channel section extends vertically. The windproof sound-permeable member includes an extension section extending upward from the top edge of the first sound inlet of the accommodation groove, and the length of the extension section of the windproof sound-permeable member is denoted as h. The size of the first sound inlet of the accommodation groove in the vertical direction is m. Wherein, the value range of h / m is: 0.125 ≤ h / m ≤ 0.6. If the value of h / m is too small (such as less than 0.125), it means that the upward extension length of the windproof sound-permeable member is small and insufficient to offset the influence of the air flow pulsation pressure, and the windproof effect is not good. If the value of h / m is too large (such as greater than 0.6), it means that the upward extension length of the windproof sound-permeable member is large. Although the windproof requirement is met, it will have an adverse impact on sound propagation, that is, a part of the sound pressure will be lost, resulting in not enough noise passing through the sound collection channel of the sound collection device and propagating to the accommodation groove, making it difficult to meet the sound pressure requirement of the sound collection element and affecting the accuracy of noise collection.

[0021] For further improvement, the windproof sound-permeable member is a sound-permeable member made of porous sound-absorbing material. Using a sound-permeable member made of damping materials such as porous sound-absorbing materials as the windproof 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 sound-permeable member can be made of polyurethane foam, melamine foam sponge, etc. The windproof sound-permeable member can not only prevent the air flow from impacting the oil-proof sound-permeable membrane 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.

[0022] In order to further improve the oil-proof effect and prevent the sound collection element from being contaminated by oil, an oil-proof sound-permeable membrane is provided in the accommodation groove to block the front side of the sound collection element. There is a fourth distance between the oil-proof sound-permeable membrane and the sound collection element, and this fourth distance is denoted as f. Wherein, the value range of f is: f ≥ 2mm.

[0023] In order to ensure the oil-proof performance of the oil-proof sound-permeable membrane and enable it to effectively transmit sound waves, the oil-proof sound-permeable membrane is a polyethylene film.

[0024] In order to prevent the oil-proof sound-permeable membrane from contacting the windproof sound-permeable member and affecting the sound transmission effect here, there is a sixth distance between the oil-proof sound-permeable membrane and the windproof sound-permeable member in the front-rear direction.

[0025] In order to facilitate the installation of the oil-proof sound-permeable membrane, an annular step portion is formed on the side wall of the accommodation groove, and the oil-proof sound-permeable membrane is provided on the annular step portion. The four peripheral edges of the oil-proof sound-permeable membrane can be fitted and installed on the annular step portion to ensure the sealing performance of the installation of the oil-proof sound-permeable membrane.

[0026] While the above-mentioned sound collection device realizes the suppression of wind noise by the sound collection element, it is also necessary to ensure that the noise signal passes through. Since the structural design of the sound collection device forms a semi-closed cavity, that is, it itself 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. Only in this way can the original noise frequencies concerned by all active noise cancellations be accurately collected. Specifically, the corresponding structural design parameters of the sound collection device must meet the following conditions: The volume of the inner cavity formed by the oil-proof sound-permeable membrane and the inner wall of the accommodation groove is denoted as V, the dimension of the main body of the wind-proof sound-permeable member in the front-rear direction is denoted as e, and the dimension of the wind-proof sound-permeable member in the up-down direction is denoted as g, where:

[0027] The technical solution adopted by the present invention to solve the second technical problem is: An oil fume extractor includes a duct for flue gas to pass through and a sound collection device provided in the duct, and the sound collection device adopts the above-mentioned sound collection device.

[0028] As an improvement, the sound collection element is a microphone.

[0029] Compared with the prior art, the advantages of the present invention are:

[0030] First, the sound propagation channel of the sound collection device is designed as a first channel section and a second channel section arranged at an angle, and the sound collection element is placed in the first channel section of the sound collection device, which can effectively isolate the interference of the air flow in the duct on the sound collection element and prevent the oil and dirt in the air flow from polluting the sound collection element. At the same time, a wind-proof sound-permeable member is also provided in the second channel section of the housing, which can effectively eliminate 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-permeable member, thereby reducing the influence on the sound collection accuracy of the microphone.

[0031] Secondly, considering that the duct environment of the range hood is full of oil stains, in order to prevent the sound collection element from being contaminated by the oil stains flowing down along the duct, in the present invention, the first channel section and the second channel section are arranged at an angle (that is, the structural design where the sound collection channel is located on the front side of the accommodation groove). This makes the entire path of the noise in the 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, but instead allows most of the oil stains to adhere to the side wall of the second channel section or the windproof sound-transmitting member. Thereby, the sound collection element can be kept 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 is designed as 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, facilitating the accurate collection of the low-frequency noise by 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 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. Finally, since a windproof sound-transmitting member is provided in the second channel section, and the sound propagation path in the collection device is a turning path, it will have an adverse effect on sound propagation, that is, a part of the sound pressure will be lost. 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 at the sound inlet), when the sound pressure L1 is lost, as a compensation, the sound inlet area S0 can be increased to maintain the sound power collected by the sound collection element. Therefore, limiting the ratio of the area S0 of the second sound inlet of the sound collection channel to the area S of the first sound inlet of the accommodation groove within a reasonable value range (S0 / S ≥ 0.18) can ensure that there is enough noise passing through the sound propagation channel of the sound collection device to compensate for the sound pressure lost due to the setting of the windproof sound-transmitting member, and further ensure that the sound pressure requirement of the sound collection element can be met when the sound propagates to the first channel section, further improving the accuracy of noise collection.

[0032] Furthermore, in the preferred embodiment, 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 member with a sufficient length needs to be provided on the second channel section to reduce wind noise and minimize 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, so that 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 reduces the wind resistance at the position where the sound collection device is located in the air duct, thus not affecting the stability of the air flow in the air duct and reducing the generation of wind noise to a certain extent. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 Schematic perspective view of the sound collection device according to Embodiment 1 of the present invention;

[0034] Figure 2 Exploded view of the sound collection device according to Embodiment 1 of the present invention;

[0035] Figure 3 Vertical sectional view of the sound collection device according to Embodiment 1 of the present invention;

[0036] Figure 4 is Figure 3 Schematic structural view after removing the windproof and sound-permeable member in;

[0037] Figure 5 is along Figure 3 Cross-sectional view taken along the A-A direction in;

[0038] Figure 6 Schematic perspective view of the sound collection device according to Embodiment 1 of the present invention installed in the air duct;

[0039] Figure 7 is Figure 6 Cross-sectional view taken along the front-rear direction;

[0040] Figure 8 Schematic view of the sound propagation process at the first sound inlet of the mounting bracket;

[0041] Figure 9 Vertical sectional view of the sound collection device according to Embodiment 2 of the present invention;

[0042] Figure 10 is Figure 9 Schematic structural view after removing the windproof and sound-permeable member in;

[0043] Figure 11Vertical sectional view of the sound collection device according to Embodiment 3 of the present invention (the mounting bracket is not provided with a hanging edge);

[0044] Figure 12 is Figure 11 Schematic structural view after omitting the windproof sound-permeable member in

[0045] Figure 13 Vertical sectional view of another structure of the sound collection device according to Embodiment 3 of the present invention (the mounting bracket is provided with a hanging edge);

[0046] Figure 14 is Figure 13 Schematic structural view after omitting the windproof sound-permeable member in

[0047] Figure 15 Vertical sectional view of the sound collection device according to Embodiment 4 of the present invention;

[0048] Figure 16 is Figure 15 Schematic structural view after omitting the windproof sound-permeable member in

[0049] Figure 17 Vertical sectional view of the sound collection device according to Embodiment 5 of the present invention;

[0050] Figure 18 is Figure 17 Schematic structural view after omitting the windproof sound-permeable member in Specific embodiments

[0051] The present invention will be further described in detail below in conjunction with the embodiments with reference to the drawings.

[0052] In the description and claims of the present invention, 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 invention. 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 invention 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.

[0053] Embodiment 1

[0054] Figures 1 - 7 A preferred embodiment of the sound collection device and the range hood of the present invention is shown.

[0055] 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 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.

[0056] 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 a kitchen appliance like an integrated stove with an oil fume suction function). 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 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 noise generated when the range hood works is collected by the microphone, 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.

[0057] 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 just 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 bracket 20 and a wind-proof cover 40.

[0058] In this embodiment, taking the box body 1 with a "channel" for the separate passage of oil fumes as an example, the specific structure of the sound collection device will be described. The channel inside the box body 1 serves as the air duct 10. The mounting bracket 20 can be mounted on the rear side wall of the air duct 10, and a receiving groove 21 for placing the sound collection element 11 is provided on its front side wall. 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 serving as the first sound inlet 211 for sound to enter the receiving groove 21. Among them, this 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. For example, Figure 8 the openings defined by boundary points such as A1 and A2 of the receiving groove 21 in the circumferential direction are not necessarily the largest open openings at the front part of the receiving groove 21. In the state where the mounting bracket 20 is mounted 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 in contact with the rear side wall of the air duct 10. To improve the accuracy of sound collection of the active noise reduction system, generally two or more sound collection elements 11 are arranged. For this reason, components such as the mounting bracket 20, the windproof sound-permeable member 30, and the windproof cover 40 are also correspondingly provided with two or more.

[0059] The mounting bracket 20 also has a third mounting portion 263 extending respectively to the left and right sides and exposed outside the windproof cover 40, and a fourth mounting portion 264 extending downward at the bottom of the mounting bracket 20 and exposed outside the windproof cover 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. A connecting post 265 extending forward is provided at the lower region position of the receiving groove 21 of the mounting bracket 20, and the windproof cover 40 can be connected to the connecting post 265 of the mounting bracket 20 by screws 50.

[0060] The windproof cover 40 includes a first side wall 411 and a second side wall 412 that are opposite and spaced apart from each other on the 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 of the windproof cover 40 is located in front of the receiving groove 21 of the mounting bracket 20. The third side wall 413 of the windproof cover 40 has a direction along the airflow in the air duct 10 (such as Figure 3The deflector surface 4130 gradually inclines towards the inside of the air duct 10 (in the direction indicated by the hollow arrow in the middle). Specifically, the deflector 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. 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 of the receiving groove 21 of the mounting frame 20 in the front-rear direction. Along the air flow direction in the air duct 10, the position where the deflector surface 4130 of the wind shield 40 is located is upstream of the position where the receiving groove 21 of the mounting frame 20 is located. Arranging the deflector surface 4130 of the wind shield 40 at a lower position also enables sufficient space to arrange components such as the windproof and sound-permeable member 30 and the oil-proof and sound-permeable film 28 at a position opposite to the front part of the receiving groove 21 inside the wind shield 40. In addition, considering that if the inclination angle of the deflector 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 deflector surface 4130 of the wind shield 40 needs to be reasonably designed. The included angle formed between the deflector 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 forward protrusion distance of the wind shield 40 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 turbulent flow problem of 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 。

[0061] To improve the anti-oil and anti-fouling effect, the wind shield 40 in this embodiment can be made of a plastic part or a metal part.

[0062] In this embodiment, a gap channel extending vertically in the front-rear direction is formed between the wind shield 40 and the front side surface of the mounting frame 20. The upper end of the gap channel (i.e., the end close to the noise source) 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 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 lower section of the sound collection channel 200 is opposite to the first sound inlet 211 at the front part of the accommodation groove 21 of the mounting frame 20 in the front-rear direction. The air duct 10 and the sound collection channel 200 in 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 B1 of the first sound inlet 211 intersects with the extension direction of the sound collection channel 200 to form a first angle M, and the value range of the first angle M is: 5° ≤ M ≤ 180°. Considering that if the angle formed between the opening direction B1 of the first sound inlet 211 and the extension direction 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 contaminate the sound collection element 11. If the angle formed between the opening direction 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 opening direction of the first sound inlet 211 and the extension direction B3 of the sound collection channel 200 also needs to be reasonably designed. Preferably, the value of the first angle M is 90°. In addition, the opening direction B4 of the second sound inlet 45 in this embodiment faces upward, that is, the opening direction of the second sound inlet 45 is also perpendicular to the opening direction B1 of the first sound inlet 211.

[0063] After the wind shield 40 is installed, it can effectively prevent the high-speed oil fume airflow from directly impacting the wind-proof sound-permeable member 30, greatly reducing the pollution of the oil fume to the wind-proof sound-permeable 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 airflow noise at the lower part and the noise interference of the secondary turbulent flow, so that the noise entering the wind-proof sound-permeable 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-permeable member 30 and minimize the contact between the wind-proof sound-permeable member 30 and the flue gas in the air duct, an extension wall 46 is provided on the upper edge of the wind shield 40 extending upward relative to the top surface of the wind-proof sound-permeable member 30, that is, the top edge of the extension wall 46 is higher than the top surface of the wind-proof sound-permeable 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 sound entering the second sound inlet 45.

[0064] Since the sound collection element 11 is installed in the receiving groove 21 of the mounting bracket 20 and a wind shield 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 and prevent the oil stain in the airflow from contaminating the sound collection element 11. At the same time, a windproof and sound-permeable element 30 is provided in the sound collection channel 200, effectively eliminating 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 element 30, thereby reducing the impact 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 extending 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 extending 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. On the other hand, considering that a windproof and sound-permeable element 30 with a sufficient length needs to be provided on the sound propagation path to prevent wind noise, thereby reducing the impact 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 element 30 is arranged in the extending direction of the air duct 10, and the sound propagation path has a turning design, so the size of the entire sound collection device in the direction perpendicular to the extending direction of the air duct 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 and also 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 orientation of the first sound inlet 211 is consistent with the extending direction of the sound collection channel, then the sound collection element 11 is easily contaminated by the oil stains flowing down along the air duct 10. Therefore, this embodiment adopts the structural design that the sound collection channel 200 is located in the front side of the receiving groove, that is, the opening orientation B1 of the first sound inlet 211 of the receiving groove 21 has a certain included angle with the extending direction of the sound collection channel. This makes the path for the noise in the air duct 10 to propagate from the second sound inlet 45 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 make most of the oil stains adhere to the side wall of the sound collection channel 200 or the windproof and sound-permeable element 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.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 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, 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.

[0065] The oil-proof sound-transmitting membrane 28 covers the first sound inlet 211 of the receiving groove 21 of the mounting frame 20, specifically at the position of the edge of the front opening of the receiving groove 21 of the mounting frame 20. More specifically, in order to facilitate the installation of the oil-proof sound-transmitting 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-transmitting membrane 28 is arranged on the annular step portion 210. In order to ensure the oil-proof performance of the oil-proof sound-transmitting membrane 28 and enable it to effectively transmit sound waves, the oil-proof sound-transmitting 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-transmitting membrane 28 and the sound collection element 11, which is denoted as f. Among them, the value range of f is: f≥2mm. 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-transmitting membrane 28 and the sound collection element 11 should refer to the distance between the oil-proof sound-transmitting membrane 28 and the microphone chip on the sound collection element 28, that is, the oil-proof sound-transmitting membrane 28 and other components (such as solder joints or fixing screws, etc.) on the circuit board where the microphone chip is located can have partial contact. The wind-proof sound-transmitting member 30 does not directly contact the oil-proof sound-transmitting membrane 28 to ensure the oil-proof effect. Specifically, there is a sixth distance between the oil-proof sound-transmitting membrane 28 and the main body of the wind-proof sound-transmitting member 30 in the front-rear direction, which is denoted as n. In order to avoid the oil-proof sound-transmitting membrane 28 contacting the wind-proof sound-transmitting member 30 and affecting the sound transmission effect here, the sixth distance n between the oil-proof sound-transmitting membrane 28 and the wind-proof sound-transmitting member 30 should be greater than 0.1mm, and the preferred range is 0.5mm - 3mm.

[0066] 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, realizing 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, which can effectively reduce the possibility of the penetration of the airflow pressure pulsation, thereby further improving the windproof effect.

[0067] 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. 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 there is a turning part in the sound propagation path of the sound collection device at the first sound inlet 211 of the accommodation groove 21, if the upward 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 influence on the accuracy of sound collection caused by the too short upward extension length of the outer peripheral edge of the windproof sound-permeable member is avoided. 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 requirement of the sound collection element 11 when propagating to the accommodation groove 21, reducing the accuracy of noise collection.

[0068] To avoid the windproof 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 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 ≥ 4 mm. Similarly, to ensure the windproof effect, the dimension (i.e., thickness) of the main body of the windproof sound-permeable component 30 in the front-rear direction is denoted as e. Among them, the value range of e is: 40 mm ≥ e ≥ 3 mm. Specifically, when e ≥ 3 mm, it can ensure that the windproof 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, therefore, the dimension (i.e., thickness) of the windproof sound-permeable component 30 in the front-rear direction cannot be too large, and e ≤ 40 mm is required. At the same time, when the dimension (i.e., thickness) of the windproof sound-permeable component 30 in the front-rear direction is certain, the dimension d1 of the main body of the windproof 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, and the value range is: 0.2 ≤ e / d1 ≤ 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 sound-permeable component 30 in the left-right direction is relatively large, and the area of its upper part in contact with the oil stain increases, which will directly affect the service life of the windproof 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 sound-permeable component 30 in the left-right direction is relatively small, which is not conducive to the sound being transmitted into the sound collection channel 200 from a relatively large angular range in the horizontal direction above, affecting the accuracy of sound collection.

[0069] Due to the setting of the windproof 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 the noise signal. Specifically, the principles of sound attenuation and compensation are as follows:

[0070] L w = L1 - ΔL + 10lgS0

[0071] Among them, the noise energy that the sound collection component can collect per unit time is the sound power L w ;

[0072] The sound pressure when the sound reaches the top surface of the windproof sound-permeable component 30 is L1;

[0073] Due to the attenuation effect of the windproof sound-permeable component 30, the lost noise sound pressure is ΔL;

[0074] The area S0 of the cross-section at the second sound inlet 45 of the sound collection channel 200;

[0075] 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 area S at the first sound inlet 211 at the front of the accommodation groove 210 needs to be reasonably limited. When the second sound inlet 45 is relatively small, such as when S0 / S is less than 0.18, it is not possible to better ensure that there is enough noise passing through the sound collection channel of the sound collection device to compensate for the sound pressure loss caused by the setting of the windproof sound-permeable member. In this case, the accuracy of sound collection is lower than 80%. Therefore, the value range of S0 / S is S0 / S ≥ 0.18. Thus, it can be ensured that there is enough noise passing through the sound collection channel 200 of the sound collection device to compensate for the sound pressure loss caused by the setting of the windproof sound-permeable member 30 and the turning of the sound propagation path, thereby ensuring that the sound pressure requirement of the sound collection element 11 can be met when the sound propagates into the accommodation groove 211, and further improving the accuracy of noise collection. On the other hand, if the opening area of the second sound inlet 45 is relatively large, such as when S0 / S is greater than 1.5, the accuracy of sound collection basically fluctuates around 98% - 99%. In this case, the improvement of the accuracy of noise collection is small, and the improvement of the active noise reduction effect is weak, but the installation space requirement for the sound collection device is larger. For this reason, the preferred value range of S0 / S is: 0.18 ≤ S0 / S ≤ 1.5. More specifically, when 0.18 ≤ S0 / S < 0.3, since the second sound inlet 45 is relatively enlarged, the sound collection channel can be made relatively unobstructed, and the accuracy of sound collection is improved, generally reaching within the range of 80 - 88%. When 0.3 ≤ S0 / S ≤ 1.5, within this range, the accuracy of noise collection is optimal, generally reaching about 91% - 98%. And the installation space requirement for the sound collection device is also relatively reasonable, and it will not overly occupy the space in the air duct 10. Therefore, the preferred value range of S0 / S is: 0.3 ≤ S0 / S ≤ 1.5.

[0076] The above-mentioned sound collection accuracy mainly refers to the degree of conformity between the noise collected by the microphone and the original noise. The specific calculation method is as follows: The collection accuracy S is the average value of the accuracy S in different one-third octave center frequency bands within the selected noise frequency range. i of the mean.

[0077]

[0078] Where: n is the number of octaves at the center of the frequency range of interest:

[0079] Accuracy S in a certain center frequency band i Calculation method:

[0080]

[0081] Where: The sound pressure value L of the collected noise at this center frequency ic ;

[0082] The sound pressure value L of the original noise at this center frequency iy ;

[0083] The dimension of the main body of the windproof sound-permeable member 30 in this embodiment in the up-down direction 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 and ensure the windproof effect, 100 mm ≥ g ≥ 10 mm. The cross-sectional area of the main body of the windproof sound-permeable member 30 near the second sound inlet 45 is S1. As shown in Figure 3 The cross-section cut along the S1-S1 direction in is the cross-sectional area of the main body of the windproof sound-permeable member 30 near the second sound inlet 45. 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 at the sound inlet), it can be known that due to the sound loss, the sound pressure decreases during the sound propagation process. 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 8 mm, and the preferred value range is: 10 mm ≤ S1 / (g / 2 + e / 2) ≤ 15 mm. 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 pass through 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 incoming sound 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 collected by 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 through 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.

[0084] 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.

[0085] 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 capacitance 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.

[0086] Among them:

[0087]

[0088] V is the volume of the cavity in the protection structure, specifically the volume of the inner cavity surrounded by the oil-proof sound-permeable membrane and the inner wall of the receiving groove of the mounting rack; ρ0 is the air density; c0 is the speed of sound in air, 343 m / s; L is the path length of sound propagation;

[0089] S0 is the effective area of sound propagation in the pipeline, and can be simplified as 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;

[0090]

[0091] 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:

[0092]

[0093] After simplification, it is:

[0094]

[0095] The protection structure of this embodiment must meet the requirements of the above formula.

[0096] 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:

[0097] S0 = ed;

[0098] 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 follows:

[0099]

[0100] Wherein, the dimension of the windproof sound-permeable member 30 in the up-down direction is denoted as g, and the dimension (i.e., thickness) of the main body of the windproof sound-permeable member 30 in the front-back direction is denoted as e.

[0101] The above-mentioned

[0102] Further simplified to:

[0103]

[0104] After installing the sound collection element 11 in the accommodation groove 21 of the mounting bracket 20 in this embodiment, an oil-proof sound-permeable membrane 28 is provided at its first sound inlet 211, a windproof sound-permeable member 30 is provided outside it, and a windproof cover 40 is provided outside the windproof sound-permeable 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 windproof cover 40 covers the windproof sound-permeable member 30, a second sound inlet 45 communicating with the outside is reserved at the leeward end. According to the law of air flow, the flow in the area of the windproof sound-permeable member 30 adjacent to the second sound inlet 45 is a low-speed and high-static-pressure area, which also effectively reduces the oil fume adhesion on the windproof sound-permeable member 30. On the other hand, it also enables noise to be effectively transmitted to the accommodation groove 21 of the mounting bracket 20 through the second sound inlet 45, ensuring the accuracy of noise data collection. On the other hand, considering the influence of the windproof sound-permeable member 30 and the windproof cover 40 on the sound propagation obstruction and loss, the ratio of the area S of the first sound inlet of the accommodation groove 21 to the area S0 of 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.

[0105] This embodiment also relates to a range hood, including a flue 10 for flue gas to pass through and an active noise reduction system provided in the flue 10. The active noise reduction system includes the above-mentioned sound collection device.

[0106] Embodiment 2

[0107] 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.

[0108] 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.

[0109] Example 3

[0110] 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 from top to bottom toward the position of the receiving 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 receiving groove 21 of the mounting bracket 20 is set obliquely upward, and its inclined direction is the same as the inclined 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 extending 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 corresponding to the upper section 201 and the lower section 202 of the sound collection channel 200 on the front wall surface of the mounting bracket 20 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 receiving 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 installing 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 installing the mounting bracket 20.

[0111] As Figure 12 shown, a second included angle N is formed at the intersection of the vertical surface 20a and the inclined surface 20b of the mounting bracket 20 in this embodiment. 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 subjected 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 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.

[0112] 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.

[0113] 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.

[0114] Example 4

[0115] 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 in it. 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 it can achieve a better oil prevention purpose, but due to the too large turning angle, certain losses are caused to the target noise, which has a certain impact on the accuracy of sound collection.

[0116] 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 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.

[0117] Embodiment 5

[0118] 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 main body 203 of the sound collection channel 200 is a vertically extending straight channel. Among them, the lower part of the sound collection channel 200 also has a horizontal section 204 extending horizontally. 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 accommodation 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 it, the propagation path of sound in the sound collection device of this embodiment is a turning path of "first downward propagation, then horizontal propagation, and finally upward propagation", as Figure 17 the turning path S shown in it. Since the sound collection channel of this embodiment is divided into two sections, a vertical section and a horizontal 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", so it can also achieve a better oil prevention purpose, but due to the too large 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.

[0119] 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 provided 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 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 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 that are sequentially connected and arranged at an angle. 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. A windproof and sound-permeable member (30) is also provided in the second channel section. The area at the above-mentioned first sound inlet (211) is denoted as S, and the area at the second sound inlet (45) is denoted as S0. The value range of S0 / S is: S0 / S ≥ 0.

18.

2. The sound collection device according to claim 1, wherein: The value range of S0 / S is: 0.18 ≤ S0 / S ≤ 1.

5.

3. The sound collection device according to claim 2, wherein: The value range of S0 / S is: 0.3 ≤ S0 / S ≤ 1.

5.

4. The sound collection device according to any one of claims 1 to 3, characterized in that: The above-mentioned sound collection device is arranged in the air duct (10) of the oil fume suction device. The second channel section 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). The opening direction (B4) of the second sound inlet (45) is consistent with the extension direction of the air duct.

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

6. The sound collection device according to claim 5, wherein: Both the second channel section and the extension direction of the air duct (10) extend vertically. The opening of the second sound inlet (45) faces upward. The opening direction (B1) of the first sound inlet (211) is perpendicular to the extension direction of the second channel section, that is, the above-mentioned first included angle is a right angle.

7. The sound collection device according to claim 4, characterized in that: The housing (2) includes a mounting frame (20) and a windproof cover (40). A receiving groove (21) is formed on the front side wall of the mounting frame (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 windproof cover (40) covers outside the mounting frame (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 windproof cover (40) and the mounting frame (20). The sound collection channel (200) constitutes the second channel section. The windward end of the windproof cover (40) and the mounting frame (20) define the second sound inlet (45).

8. The sound collection device according to claim 7, characterized in that: The front side wall of the windproof and sound-permeable member (30) is attached to the rear side wall of the windproof cover (40).

9. The sound collection device according to claim 4, characterized in that: The second channel section extends vertically. The dimension of the part of the windproof sound-permeable member (30) adjacent to the second sound inlet (45) in the front-rear direction is denoted as e, and the dimension in the left-right direction is denoted as d1. Among them, the value range of e / d1 is: 0.2 ≤ e / d1 ≤ 0.5, and the value range of e is 3 mm ≤ e ≤ 40 mm.

10. The sound collection device according to claim 7, wherein: The second channel section extends vertically. The windproof sound-permeable member (30) includes an extension section extending upward from the top edge of the first sound inlet (211) of the accommodation groove (21), and the length of the extension section of the windproof sound-permeable member (30) is denoted as h. 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 ≤ h / m ≤ 0.

6.

11. The sound collection device according to any one of claims 1 to 3, characterized in that: The windproof sound-permeable member (30) is a sound-permeable member made of porous sound-absorbing material.

12. An oil fume suction machine, comprising a duct (10) for flue gas to pass through and a sound collection device disposed in the duct (10), characterized in that: The described sound collection device adopts the sound collection device described in any one of claims 1 to 11.

13. The range hood according to claim 12, wherein: The described sound collection element (11) is a microphone.

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