Sound acquisition device and range hood

Abstract

The sound acquisition device comprises a sound acquisition 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, the first channel section and the second channel section are sequentially connected, and an included angle is formed between the first channel section and the second channel section. 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 utility model relates to the technical field of range hoods, in particular to a sound collection device and a range hood. Background Art

[0002] A range hood is a kitchen appliance that purifies the kitchen environment. The noise problem of range hoods has always been one of the main problems that bother users. Active noise reduction, as a new noise reduction technology, is also being considered for use in range hoods to reduce noise. 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 waves are transmitted to the controller in the form of electrical signals. After analysis and processing, the controller sends instructions to the speaker to control the speaker to emit sound waves that match the noise sound waves to neutralize the noise sound waves, thereby achieving the effect of noise reduction. For example, the Chinese invention patent application with application number CN202010935185.0 (application publication number: CN111928310A) discloses a range hood with active noise reduction function. The microphone of the range hood is arranged in the casing and is distributed around the fan in an array, and the speaker assembly is distributed below the fan. For example, similar disclosures were made in the “Ranger hood and its active noise reduction device” with application number CN202221822214.3 and the “Low-noise range hood” with application number CN202222650354.3.

[0003] In order to ensure the noise reduction effect, all microphones and speakers used in the active noise reduction system in the existing technology are often arranged in the internal air duct of the range hood. However, due to the oily environment of the range hood, the microphones and speakers are often contaminated, resulting in the active noise reduction system's noise reduction effect decreasing as the use time increases, or even causing failure. To this end, Chinese utility model patent application number CN201820250745.7 discloses an active noise reduction device for a range hood with an oil prevention device, comprising an input device, a central data processor, and a noise reduction unit. The input device includes a microphone, which is arbitrarily installed at any location on the range hood. The noise reduction unit includes at least two noise reduction boxes, which are located at the bottom of the range hood's volute, facing the air inlet. An oil prevention device is located below the noise reduction box, which is also located at the bottom of the volute and covers the noise reduction box. The oil prevention device includes a porous sound-transmitting shell and an oil-proof and sound-transmitting film attached to the surface of the porous sound-transmitting shell. At least one noise reduction speaker is located in the noise reduction box. Both the microphone and the noise reduction speaker are connected to the central data processor. The central data processor loads a noise reduction device self-test module and an oil pollution detection module. The oil pollution detection module detects oil pollution damage to the oil prevention device. The self-test module receives and processes the system signal reported by the device to determine whether the microphone and the noise reduction speaker have been added. At the same time, a timing detection module is provided in the self-test 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. Utility Model Content

[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 defines a sound propagation channel, the sound propagation channel includes a first channel section and a second channel section that are 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 collecting device is designed to be a first channel section and a second channel section arranged at an angle, and the sound collecting element is placed in the first channel section of the sound collecting device. This can effectively isolate the airflow in the air duct from interfering with the sound collecting element and prevent oil pollution in the airflow from contaminating the sound collecting element. At the same time, a windproof and sound-permeable component is also provided in the second channel section of the shell to effectively prevent wind noise. Even if a small amount of airflow enters the sound collecting channel, the pressure pulsation can be weakened in the windproof and sound-permeable component, thereby reducing the impact on the accuracy of microphone sound collection. Considering that the range hood air duct is often filled with oil, to prevent the sound collection element from being contaminated by oil flowing down the duct, the first and second channel sections of the present invention are arranged at an angle. This creates a curved path for the noise in the air duct, from the second sound inlet to the second channel section and then to the location of the sound collection element in the first channel section. This curved path prevents excessive oil from directly passing through the sound propagation channel and coming into contact with the sound collection element. Instead, it directs most of the oil to the sidewalls of the second channel section or the windproof and sound-permeable member, thereby keeping the sound collection element as far away from the oil as possible and extending its service life. Furthermore, considering that the target noise to be collected by the active noise reduction system (primarily from the fan system) is low-frequency noise, the curved path design of the sound propagation path within the sound collection device attenuates high-frequency sounds (such as the high-frequency portion of wind noise and non-target noise such as high-frequency sound components generated by the fan system) while having minimal impact on low-frequency sounds. Therefore, it is well suited for propagating low-frequency noise within the sound collection device, facilitating accurate collection by the sound collection element. The main reason is that low-frequency noise has a longer wavelength and can better adapt to the bends and irregular shapes of the pipe. When low-frequency noise propagates in a curved pipe, due to its longer wavelength, it is not easily obstructed and reflected by the pipe, so it can propagate and diffuse better. High-frequency noise has a shorter wavelength and is easily reflected and absorbed by the shape and bend of the pipe, so it is more difficult to propagate and diffuse in the pipe than low-frequency noise. Finally, since windproof and sound-permeable parts are provided in the second channel section, and the propagation path of sound in the collection device is a turning path, it will have an adverse effect on sound propagation, that is, some sound pressure will be lost. According to the sound propagation principle, L w =L1+101gS(L Wis sound power, L1 is sound pressure, and S is the area at the sound entrance). When the sound pressure L1 is lost, the sound power collected by the sound collecting element can be maintained by increasing the sound entrance area S0 as compensation. Therefore, the ratio of the area S0 of the second sound entrance of the sound collecting channel to the area S of the first sound entrance of the accommodating groove is limited to a reasonable value range (S0 / S≥0.18). This can ensure that sufficient noise can pass through the sound propagation channel of the sound collecting device to compensate for the sound pressure loss caused by the provision of the windproof and sound-permeable component, thereby ensuring that the sound can meet the sound pressure requirement of the sound collecting element when propagating to the first channel section, thereby further improving the accuracy of noise collection.

[0009] When the second sound entrance is relatively small, such as when S0 / S is less than 0.18, it cannot be ensured that sufficient noise can pass through the sound collection channel of the sound collection device to compensate for the sound pressure loss due to the setting of the windproof and sound-permeable component. In this case, the accuracy of sound collection is less than 80%; on the other hand, if the opening area of the second sound entrance is relatively large, such as when S0 / S is greater than 1.5, the accuracy of sound collection basically fluctuates around 98% to 99%. In this case, the accuracy of noise collection is improved less, 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.

[0010] As an improvement, when 0.18≤S0 / S<0.3, due to the relative increase in the second sound inlet, the sound collection channel can be made relatively unobstructed, and the accuracy of sound collection is improved, generally reaching 80% to 88%. When 0.3≤S0 / S≤1.5, within this range, the accuracy of noise collection is optimal, generally reaching about 91% to 98%. In addition, the installation space requirements of the sound collection device are relatively reasonable, and will not excessively occupy the space in the air duct. Therefore, the preferred value range of S0 / S is: 0.3≤S0 / S≤1.5.

[0011] As an improvement, the above-mentioned sound collection device is arranged in the air duct of the range fumes extraction device, the second channel section is arranged along the extension direction of the air duct, and the second sound inlet is formed at the leeward end of the shell, and the opening direction of the second sound inlet is consistent with the extension direction of the air duct.

[0012] The above-mentioned “end portion of the housing facing leeward” may be understood as: an end of the housing adjacent to the fan system of the range hood along the extension direction of the air duct.

[0013] The above-mentioned "the second channel section is arranged along the extension direction of the air duct" can be understood as the overall extension direction of the second channel section being consistent with or parallel to the extension direction of the air duct, or it can be understood as the overall extension direction of the second channel section having a slight inclination angle relative to the extension direction of the air duct (such as an inclination angle of 0-30°).

[0014] The second channel section can be a straight channel structure, or a non-straight channel structure with partial bends or curves. In order to avoid the adverse effect on sound propagation caused by too many turns in the sound propagation path of the sound collection device, and taking into account the convenience of installing components such as windproof and sound-permeable parts in the second channel section, the main body of the second channel section will adopt a straight channel consistent with the extension direction of the air duct. Generally speaking, in order to minimize the oil contamination of the sound collection elements in the first channel section, the direction of the first sound inlet should avoid being consistent with the extension direction of the second channel section, that is, the opening direction of the first sound inlet should be set at an angle to the extension direction of the second channel section, but the first sound inlet is preferably set at an angle to the extension direction of the second channel section. The angle formed between the direction and the extension direction of the second channel segment also needs to be reasonably designed. If the angle formed between the direction of the first sound inlet and the extension direction of the second channel segment is too small, the oil will still enter the first channel segment through the first sound inlet and contaminate the sound collecting element. If the angle formed between the direction of the first sound inlet and the extension direction of the second channel segment is too large, the sound propagation path will turn too much, which will have an adverse effect on sound propagation, that is, part of the sound pressure will be lost, which is not conducive to the accurate collection of noise by the sound collecting element. For this reason, preferably, the value range of the first angle formed by the intersection of the opening direction of the first sound inlet and the extension direction of the second channel segment is: 5°≤M≤180°.

[0015] In order to better prevent the sound collecting elements from contacting oil and improve the windproof effect, the extension direction of the second channel section and the air duct are both vertically extended, the opening of the second sound inlet is upward, and the opening of the first sound inlet is perpendicular to the extension direction of the second channel section, that is, the first angle is a right angle.

[0016] The shell can be designed with an integrated structure, such as an integrated curved pipe structure, but in order to facilitate the installation of components such as sound collecting elements, the shell preferably adopts a split structure design assembled together by fasteners. Specifically, the shell includes a mounting frame and a windshield. A receiving groove is provided on the front side wall of the mounting frame. The sound collecting element is placed in the receiving groove. The receiving groove constitutes the first channel section. The front opening of the receiving groove is the first sound inlet. The windshield is arranged outside the mounting frame and defines a sound collecting channel between the mounting frame and the mounting frame, which is connected to the first sound inlet of the receiving groove and is located on the front side of the receiving groove. The sound collecting channel constitutes the second channel section.

[0017] As an improvement, the front sidewall of the windproof and sound-permeable member is in contact with the rear sidewall of the windshield. This structural design compresses the windproof and sound-permeable member, which increases the material density and effectively reduces the possibility of airflow pressure pulsation penetrating the member, thereby further improving the windproof effect.

[0018] To ensure effective wind protection, the thickness (i.e., the dimension in the front-to-back direction) of the windproof and sound-permeable member must be appropriately designed. Furthermore, to minimize the impact of the windproof and sound-permeable member on sound transmission loss, the left-to-right dimension of the portion of the windproof and sound-permeable member adjacent to the second sound inlet must also be appropriately designed. Specifically, the second channel section extends vertically. The front-to-back dimension of the portion of the windproof and sound-permeable member adjacent to the second sound inlet is denoted by e, and the left-to-right dimension is denoted by d1. 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. To ensure that the windproof and sound-permeable member effectively prevents airflow in the air duct from directly impacting the sound collecting element, the front-to-back dimension (i.e., thickness) of the windproof and sound-permeable member must be e ≥ 3 mm. Furthermore, considering the adverse effects of the windproof and sound-permeable member (typically made of a porous material that is both airflow-resistant and sound-permeable) on sound transmission, the front-to-back dimension (i.e., thickness) of the windproof and sound-permeable member must be limited to a value of e ≤ 40 mm. At the same time, when the size of the windproof and sound-permeable component in the front-to-back direction (that is, the thickness) is constant, the size d1 of the main body of the windproof and sound-permeable component in the left-to-right direction must also be adapted thereto. If e / d1 is too small, it means that the main body of the windproof and sound-permeable component is larger in the left-to-right direction, and the area of its upper part in contact with oil and dirt increases, affecting the service life of the windproof and sound-permeable component. If e / d1 is too large, it means that the main body of the windproof and sound-permeable component is smaller in the left-to-right direction, which is not conducive to the transmission of sound from a larger lateral angle range above to the sound collection channel, affecting the accuracy of sound collection.

[0019] As the size of the windproof and sound-permeable part in the up-down direction increases, the windproof effect increases, but it also means that the loss of sound during the propagation process in the sound collecting device increases. Therefore, on the basis that the size of the windproof and sound-permeable part in the up-down direction meets the conditions, the sound transmission area of the windproof and sound-permeable part must be adapted to the size range of the windproof and sound-permeable part in the up-down direction to ensure that there are enough noises to be collected to enter the sound collecting channel, thereby further reducing the influence of the windproof and sound-permeable part on the sound propagation loss. Specifically, the cross-sectional area of the main body of the windproof and sound-permeable part adjacent to the second sound inlet is S1, the size of the part of the windproof and sound-permeable part adjacent to the second sound inlet in the front-to-back direction is denoted as e, and the size of the main body of the windproof and sound-permeable part in the up-down direction is denoted as g, g / 2+e / 2 represents the length of the sound propagation path in the windproof and sound-permeable part. When the propagation path is longer, the sound loss is greater. According to the sound propagation principle L w =L1+101gS(L W is sound power, L1 is sound pressure, and S is the area at the sound entrance). Due to sound loss, the sound pressure decreases during sound propagation. As compensation, S1 should be increased to ensure that enough sound is collected by the sound collecting element. Therefore, considering the sound propagation loss and compensation, the value of S1 / (g / 2+e / 2) should be greater than 8mm, and the preferred value range is: 10mm≤S1 / (g / 2+e / 2)≤15mm. If S1 / (g / 2+e / 2) is too small, such as S1 / (g / 2+e / 2)≤8, it means that the entrance area of the windproof and sound-permeable component at the end position adjacent to the second sound entrance for effective sound transmission from top to bottom is small, and the amount of sound entering is insufficient to balance the adverse effects of the windproof and sound-permeable component on sound loss in the up-down and front-to-back directions, thereby reducing the accuracy of sound collection by the sound collecting element. If S1 / (g / 2+e / 2) is too large, such as S1 / (g / 2+e / 2)≥15, it means that the entrance area of the windproof and sound-permeable component at the end position adjacent to the second sound entrance for effective transmission of sound from top to bottom is large. Similarly, the area of the upper part of the windproof and sound-permeable component that contacts oil and dirt increases, affecting the service life of the windproof and sound-permeable component.

[0020] As an improvement, the second channel section extends vertically, and the windproof sound-permeable member includes an extension section extending upward from the top edge of the first sound inlet of the receiving slot, with the length of the extension section of the windproof sound-permeable member being denoted as h, and the vertical dimension of the first sound inlet of the receiving slot being denoted as m. The value range of h / m is 0.125 ≤ h / m ≤ 0.6. If the value of h / m is too small (e.g., less than 0.125), the upward extension length of the windproof sound-permeable member is too small to offset the influence of airflow pulsation pressure, resulting in poor windproof effect. If the value of h / m is too large (e.g., greater than 0.6), the upward extension length of the windproof sound-permeable member is too large. Although the windproof requirement is met, it will have an adverse effect on sound propagation, that is, a portion of sound pressure will be lost, resulting in insufficient noise from passing through the sound collection channel of the sound collection device to be transmitted to the receiving slot, making it difficult to meet the sound pressure requirement of the sound collection element, thereby affecting the accuracy of noise collection.

[0021] A further improvement is that the windproof and sound-permeable member is made of a porous sound-absorbing material. Using a damping material such as a porous sound-absorbing material as a windproof and sound-permeable member can slow down airflow, eliminate airflow impact, and ensure that the collected sound can pass through. Specifically, polyurethane foam, melamine foam, or the like can be used for the windproof and sound-permeable member. This windproof and sound-permeable member prevents airflow from impacting the oil-proof sound-permeable membrane and generating additional noise. Furthermore, the porous nature of the material absorbs high-frequency components of sound energy, thereby filtering out noise signals.

[0022] In order to further improve the oil-proof effect and prevent the sound collecting element from being contaminated by oil, the accommodating groove is further provided with an oil-proof sound-permeable membrane that blocks the front side of the sound collecting element. A fourth distance is provided between the oil-proof sound-permeable membrane and the sound collecting element. The fourth distance is denoted as f, where 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 there, the oil-proof sound-permeable membrane and the windproof sound-permeable member have a sixth distance in the front-to-back direction.

[0025] To facilitate installation of the oil-proof acoustic membrane, an annular step is formed on the sidewall of the receiving groove, and the oil-proof acoustic membrane is mounted on the annular step. The four edges of the oil-proof acoustic membrane can be fitted onto the annular step to ensure a tight seal during installation.

[0026] The above-mentioned sound collection device can suppress wind noise while ensuring that the noise signal passes through. Since the structure design of the sound collection device forms a semi-enclosed cavity, that is, it forms a low-pass filter, it is necessary to make the cutoff frequency f of the structure itself c Greater than the upper frequency limit f of active noise reduction a , in order to accurately collect all the original noise frequencies of interest for active noise reduction, specifically, the corresponding structural design parameters of the sound collection device must meet the following conditions: the volume of the inner cavity enclosed by the oil-proof sound-permeable membrane and the inner wall of the receiving groove is denoted as V, the dimension of the main body of the windproof sound-permeable member in the front-to-back direction is denoted as e, and the dimension of the windproof sound-permeable member in the vertical direction is denoted as g, where:

[0027] The technical solution adopted by the present invention to solve the second technical problem is: a range hood, including an air duct for smoke to pass through and a sound collection device arranged in the air duct, and the sound collection device adopts the above-mentioned sound collection device.

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

[0029] Compared with the prior art, the advantages of this utility model are:

[0030] First, the sound propagation channel of the sound collecting device is designed to be a first channel section and a second channel section arranged at an angle, and the sound collecting element is placed in the first channel section of the sound collecting device, which can effectively isolate the interference of the airflow in the air duct on the sound collecting element and prevent the oil in the airflow from contaminating the sound collecting element. At the same time, a windproof and sound-permeable component is also provided in the second channel section of the shell, which can effectively prevent wind noise. Even if a small amount of airflow enters the sound collecting channel, the pressure pulsation can be weakened in the windproof and sound-permeable component, thereby reducing the impact on the accuracy of microphone sound collection.

[0031] Secondly, considering that the air duct environment of the range hood is full of oil and dirt, in order to prevent the sound collecting element from being contaminated by the oil and dirt flowing down the air duct, the first channel section and the second channel section in the utility model are arranged at an angle (that is, the structural design of the sound collecting channel is located on the front side of the accommodating groove). This makes the entire path of the noise in the air duct from the second sound inlet into the second channel section and then propagating to the position of the sound collecting element in the first channel section a turning path. This turning path can prevent excessive oil and dirt from directly passing through the sound propagation channel and contacting the sound collecting element, but instead makes most of the oil and dirt adhere to the side wall of the second channel section or the windproof and sound-permeable component, thereby keeping the sound collecting element as far away from the oil and dirt as possible, thereby extending the service life of the sound collecting element. On the other hand, considering that the target noise (mainly from the fan system) that the active noise reduction system needs to collect is low-frequency noise, the sound propagation path in the sound collection device adopts a turning path design, which has a weakening effect on high-frequency sounds (such as the high-frequency sound part of wind noise and non-target noise such as the high-frequency sound components generated by the fan system), but has less impact on low-frequency sounds. Therefore, it is well suited for the propagation of low-frequency noise in the sound collection device, which is conducive to the accurate collection of it by the sound collection element. The main reason is that the wavelength of low-frequency noise is longer and can better adapt to the bends and irregular shapes of the pipe. When low-frequency noise propagates in a curved pipe, due to its longer wavelength, it is not easily obstructed and reflected by the pipe, so it can be better propagated and diffused. High-frequency noise has a shorter wavelength and is easily reflected and absorbed by the shape and bend of the pipe. Therefore, it is more difficult to propagate and diffuse in the pipe than low-frequency noise. Finally, since a windproof and sound-permeable component is set 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, some sound pressure will be lost. According to the sound propagation principle, L w =L1+101gS(L W is sound power, L1 is sound pressure, and S is the area at the sound entrance). When the sound pressure L1 is lost, the sound power collected by the sound collecting element can be maintained by increasing the sound entrance area S0 as compensation. Therefore, the ratio of the area S0 of the second sound entrance of the sound collecting channel to the area S of the first sound entrance of the accommodating groove is limited to a reasonable value range (S0 / S≥0.18). This can ensure that sufficient noise can pass through the sound propagation channel of the sound collecting device to compensate for the sound pressure loss caused by the provision of the windproof and sound-permeable component, thereby ensuring that the sound can meet the sound pressure requirement of the sound collecting element when propagating to the first channel section, thereby 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) is propagated along the extension direction of the air duct, and the propagation direction is opposite to the flow direction of the airflow in the air duct, the second channel section is arranged along the extension direction of the air duct, and the second sound inlet of the second channel section is directed towards the sound source so as to directly receive the noise in the air duct. On the other hand, considering that a windproof and sound-permeable component of sufficient length needs to be provided on the second channel section to prevent wind noise in order to reduce the influence of the airflow in the air duct on sound collection, the utility model arranges the second channel section in the extension direction of the air duct, so that the size of the entire sound collection device perpendicular to the extension direction of the air duct can be made smaller, that is, the space occupied in the air duct of the range hood is smaller, thereby making the wind resistance at the position where the sound collection device is located in the air duct smaller, so that it will not affect the stability of the airflow in the air duct, and at the same time, the generation of wind noise is reduced to a certain extent. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 This is a schematic diagram of the three-dimensional structure of the sound collection device of Example 1 of the present utility model;

[0034] Figure 2 This is an exploded view of the sound collection device of Example 1 of the present utility model;

[0035] Figure 3 This is a vertical cross-sectional view of the sound collection device of Example 1 of the present utility model;

[0036] Figure 4 for Figure 3 The schematic diagram of the structure after omitting the windproof and sound-permeable parts;

[0037] Figure 5 For the Figure 3 Sectional view cut along the AA direction;

[0038] Figure 6 This is a schematic diagram of the three-dimensional structure of the sound collection device of Example 1 of the utility model installed in the air duct;

[0039] Figure 7 for Figure 6 a transverse cross-sectional view cut along the anterior-posterior direction;

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

[0041] Figure 9 This is a vertical cross-sectional view of the sound collection device of Example 2 of the present utility model;

[0042] Figure 10 for Figure 9 The schematic diagram of the structure after omitting the windproof and sound-permeable parts;

[0043] Figure 11 This is a vertical cross-sectional view of the sound collection device of Example 3 of the present utility model (the mounting frame does not have a hanging edge);

[0044] Figure 12 for Figure 11 The middle diagram is a structural diagram after omitting the windproof and sound-permeable components;

[0045] Figure 13 This is a vertical sectional view of another structure of the sound collection device of Example 3 of the present utility model (with a hanging retaining edge on the mounting frame);

[0046] Figure 14 for Figure 13 The middle diagram is a structural diagram after omitting the windproof and sound-permeable components;

[0047] Figure 15 This is a vertical cross-sectional view of the sound collection device of Example 4 of the present utility model;

[0048] Figure 16 for Figure 15 The middle diagram is a structural diagram after omitting the windproof and sound-permeable components;

[0049] Figure 17 This is a vertical cross-sectional view of the sound collection device of Example 5 of the present utility model;

[0050] Figure 18 for Figure 17 The schematic diagram of the structure after omitting the windproof and sound-permeable parts. DETAILED DESCRIPTION

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

[0052] In the specification and claims of the present invention, directional terms such as "front," "back," "up," "down," "left," "right," "side," "top," and "bottom" are used to describe various exemplary structural parts and components of the present invention. However, these terms are used herein for convenience of description only and are based on the exemplary orientations shown in the accompanying drawings. Since the embodiments disclosed in the present invention can be arranged in different orientations, these directional terms are intended for illustrative purposes only and should not be construed as limiting. For example, "up" and "down" are not necessarily limited to directions opposite to or consistent with the direction of gravity.

[0053] Example 1

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

[0055] The sound collection device includes a sound collection element 11 and a housing 2. The housing 2 defines a sound propagation channel, which includes a first channel section and a second channel section connected in sequence. The sound collection element 11 is located in the first channel section. The first channel section has a first sound inlet 211 connected to the second channel section. The second channel section has a second sound inlet 45 for external sound to enter. The extension line of the opening direction of the first sound inlet 211 intersects the extension line of the opening direction of the second sound inlet 45. In a preferred embodiment, the first and second channel sections are both linear channels, wherein the extension line of the first channel section intersects the extension line of the second channel section. The extension line of the first channel section can be understood as the line connecting the location of the sound inlet of the channel section to the location of the sound collection element 11, and the extension line of the second channel section can be understood as the line connecting the location of the sound inlet of the channel section to the location of the sound outlet.

[0056] An active noise reduction system is typically installed in the air duct 10 of a range hood (such as a range hood or a kitchen appliance with a range hood extraction function, such as an integrated stove). The sound collection device, a key component of the active noise reduction system, is also installed in the range hood's air duct 10. Taking a range hood as an example, the "air duct" mentioned above can refer to the range hood's casing or a box structure with a separate "channel" for oil fumes to pass through, such as the channel between the fan system and the range hood's fume collection hood in a ceiling-mounted range hood. The active noise reduction system generally includes a sound collection element 11 (microphone) and a speaker. The microphone collects the noise generated by the range hood during operation and transmits the collected noise waves as electrical signals to a controller. The controller analyzes and processes the noise and issues a command to the speaker, controlling it to emit sound waves that match the noise waves, thereby neutralizing the noise and achieving the desired noise reduction effect. The sound collection device of this embodiment can be used to mount the sound collection element 11 and provide protection against oil and wind.

[0057] The sound collection device is located below the fan system. This means that the noise generated by the fan system propagates downward along the air duct 10, and the sound collection device is positioned precisely along this path within the duct 10. In addition to the housing, the sound collection device also includes an oil-proof, sound-permeable membrane 28 and a windproof, sound-permeable member 30. The housing also includes a mounting bracket 20 and a windshield 40.

[0058] This embodiment takes the case 1 having a "channel" for oil smoke to pass through separately as an example to illustrate the specific structure of the sound collection device. The channel in the case 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 the front side wall thereof. The receiving groove constitutes the first channel section of the above-mentioned shell 2. The front portion of the receiving groove 21 has an opening as a first sound inlet 211 for sound to enter the receiving groove 21. The first sound inlet 211 should be understood as an opening for sound from the outside (the sound collection channel in this embodiment) to enter the receiving groove 21 and be effectively collected by the sound collection element, such as Figure 8 The circumferential opening defined by boundary points A1 and A2 of the middle receiving slot 21 is not necessarily the maximum opening at the front of the receiving slot 21. When the mounting bracket 20 is properly installed on the rear wall of the air duct 10, the rear wall of the portion of the mounting bracket 20 where the receiving slot 21 is located abuts against the rear wall of the air duct 10. To improve the accuracy of sound collection in the active noise reduction system, two or more sound collection elements 11 are typically provided. To this end, two or more components, such as the mounting bracket 20, the windproof and sound-permeable member 30, and the windshield 40, are also provided.

[0059] The mounting frame 20 also has third mounting portions 263 extending to the left and right, respectively, to expose the exterior of the wind shield 40. A fourth mounting portion 264 extending downward from the bottom of the mounting frame 20 to expose the exterior of the wind shield 40 is also provided. Both the third mounting portion 263 and the fourth mounting portion 264 are screwed to the sidewalls of the air duct 10. The lower area of the receiving slot 21 of the mounting frame 20 has forward-extending connecting posts 265, to which the wind shield 40 is connected via screws 50.

[0060] The wind shield 40 includes a first side wall 411 and a second side wall 412 that are arranged opposite to each other and spaced apart, and a third side wall 413 that is connected between the front edge of the first side wall 411 and the front edge of the second side wall 412. The third side wall 413 of the wind shield 40 is located in front of the receiving slot 21 of the mounting bracket 20. The third side wall 413 of the wind shield 40 has a shape that is arranged along the direction of airflow in the air duct 10 (e.g., Figure 3The guide surface 4130 (in the direction indicated by the hollow arrow) gradually tilts toward the interior of the air duct 10. Specifically, the guide surface 4130 is located at the lower portion of the third side wall 413, that is, at the end of the third side wall 413 that faces the wind. It tilts forward from bottom to top, while the upper portion of the third side wall 413 extends substantially vertically and is opposite to the portion of the mounting bracket 20 where the receiving slot 21 is located in the front-to-back direction. Along the direction of airflow within the air duct 10, the guide surface 4130 of the wind shield 40 is located upstream of the receiving slot 21 of the mounting bracket 20. Positioning the guide surface 4130 of the wind shield 40 downward also allows sufficient space within the wind shield 40, opposite the front portion of the receiving slot 21, to accommodate components such as the windproof and sound-permeable member 30 and the oil-proof and sound-permeable membrane 28. Furthermore, considering that an excessively large inclination angle of the guide surface 4130 toward the interior of the air duct 10 could affect the flow of air within the air duct 10 to a certain extent, such as affecting the air volume flowing within the air duct 10 or generating additional noise, the inclination angle of the guide surface 4130 of the wind shield 40 needs to be appropriately designed. The angle formed between the guide surface 4130 of the wind shield 40 and the sidewall of the air duct 10 on which the wind shield 40 is mounted is denoted as A, with a value range of A ≤ 60°. To reduce the impact of the installation of the sound collection device on the flow field within the air duct 10, the dimension of the air duct 10 in the front-to-back direction of this embodiment is denoted as a, and the distance that the wind shield 40 protrudes forward relative to the sidewall of the air duct 10 on which the wind shield 40 is mounted is denoted as b. Considering that if the distance that the wind shield 40 protrudes forward is too large, such as b / a>0.35, on the one hand, it will affect the air volume flowing in the air duct 10, and on the other hand, it will also cause the air flow to be disturbed at the position where the sound collection device is located in the air duct 10, generating additional noise and affecting the accuracy of sound collection, the value of b / a needs to be reasonably limited. In this embodiment, preferably, b / a≤0.35, see Figure 7 .

[0061] In order to improve the oil-proof effect, the windshield 40 of this embodiment can be made of plastic or metal.

[0062] In this embodiment, the windshield 40 and the front side of the mounting frame 20 form a vertically extending gap channel in the front-to-back direction. This gap channel is open at its upper end (i.e., the end closest to the noise source) and closed at its lower end (i.e., the end further from the noise source). This gap channel serves as the sound collection channel 200. Located on the front side of the mounting frame 20, it constitutes the second channel section of the housing 2. More specifically, a second sound inlet 45, communicating with the sound collection channel 200, is defined between the leeward end of the windshield 40 (i.e., the section near the range hood's fan system along the air duct's extension direction) and the front sidewall of the mounting frame 20. The lower section of the sound collection channel 200 is aligned with the first sound inlet 211 at the front of the receiving slot 21 of the mounting frame 20 in the front-to-back direction. In this embodiment, the air duct 10 and the sound collection channel 200 both extend vertically, meaning that the sound collection channel 200 extends in the same direction (B2) as the air duct 10. The opening direction B1 of the first sound inlet 211 intersects the extension direction of the sound collection channel 200 to form a first angle M. The range of the first angle M is 5°≤M≤180°. Considering that if the angle between the orientation B1 of the first sound inlet 211 and the extension direction of the sound collection channel 200 is too small, oil may still enter the receiving groove 21 through the first sound inlet 211 and contaminate the sound collection element 11. If the angle between the orientation B1 of the first sound inlet 211 and the extension direction B3 of the sound collection channel 200 is too large, the sound propagation path will bend too sharply, which will adversely affect sound propagation. In other words, some sound pressure will be lost, which is not conducive to the sound collection element's accurate noise collection. Therefore, the angle between the orientation of the first sound inlet 211 and the extension direction B3 of the sound collection channel 200 should also be reasonably designed. Preferably, the first angle M is 90°. In addition, the opening direction B4 of the second sound entrance 45 of this embodiment is upward, that is, the opening direction of the second sound entrance 45 is also perpendicular to the opening direction B1 of the first sound entrance 211 .

[0063] After the windshield 40 is installed, it can effectively prevent high-speed oil smoke airflow from directly impacting the windproof and sound-permeable member 30, greatly reducing the pollution of the windproof and sound-permeable member 30 by oil smoke. At the same time, after the windshield 40 is matched with the mounting bracket 20, only the second sound inlet 45 at the top is retained, directly isolating the noise of the lower airflow and the noise interference of the secondary turbulence, so that the noise entering the windproof and sound-permeable member 30 mainly comes from above, that is, the direction of the main noise source of the range hood, thereby ensuring the accuracy of noise collection. In a preferred embodiment, in order to improve the protective effect of the windshield 40 on the windproof and sound-permeable member 30 and minimize the contact of the windproof and sound-permeable member 30 with the smoke in the air duct, an extension wall 46 is extended upward from the upper edge of the windshield 40 relative to the top surface of the windproof and sound-permeable member 30, that is, the top edge of the extension wall 46 is higher than the top surface of the windproof and sound-permeable member 30. Affected by the air flow in the air duct 10, an air vortex will be formed at the leeward end of the wind shield 40 (that is, the second sound inlet 45), which will produce more obvious wind noise. The setting of the extension wall 46 of the above-mentioned wind shield 40 can make the air vortex as far away from the second sound inlet 45 as possible, thereby avoiding the air vortex from affecting the sound entering the second sound inlet 45.

[0064] Since the sound collecting element 11 is installed in the receiving groove 21 of the mounting frame 20 and a windproof cover 40 is provided outside the mounting frame 20, the interference of the airflow in the air duct 10 on the sound collecting element 11 can be effectively isolated, and the oil in the airflow is prevented from contaminating the sound collecting element 11. At the same time, a windproof and sound-permeable member 30 is provided in the sound collecting channel 200 to effectively prevent wind noise. Even if a small amount of airflow enters the sound collecting channel 200, the pressure pulsation can be weakened in the windproof and sound-permeable member 30, thereby reducing the impact on the accuracy of the microphone sound collection. Furthermore, considering that the noise within the air duct 10 (primarily originating from the fan system) propagates along the extension direction of the air duct 10 and in a direction opposite to the direction of airflow within the air duct 10, arranging the sound collection channel 200 along the extension direction of the air duct allows the second sound inlet 45 of the sound collection channel 200 to face the sound source so as to directly receive the noise. Furthermore, considering that a sufficiently long windproof and sound-permeable member 30 is required along the sound propagation path to prevent wind noise and thereby reduce the impact of airflow within the air duct 10 on sound collection, in this embodiment, the sound collection channel 200 for accommodating the windproof and sound-permeable member 30 is arranged along the extension direction of the air duct 10, and the sound propagation path has a bend design. This allows the entire sound collection device to be made smaller in the direction perpendicular to the extension direction of the air duct, i.e., it occupies less space within the air duct 10 of the range hood. This, in turn, reduces wind resistance at the location of the sound collection device within the air duct 10. Consequently, the stability of the airflow within the air duct is not affected, while also reducing wind noise generation to a certain extent. On this basis, considering that the range hood air duct environment is filled with oil, if the orientation of the first sound inlet 211 is consistent with the extension direction of the sound collection channel, the sound collection element 11 is easily contaminated by the oil flowing down the air duct 10. Therefore, this embodiment adopts a structural design in which the sound collection channel 200 is located at the front side of the receiving tank. That is, the opening direction B1 of the first sound inlet 211 of the receiving tank 21 forms a certain angle with the extension direction of the sound collection channel. This results in a curved path for the noise in the air duct 10 to propagate from the second sound inlet 45 to the location of the sound collection element 11 in the receiving tank 21. This curved path prevents excessive oil from directly passing through the sound collection channel 200 and coming into contact with the sound collection element 11. Instead, most of the oil adheres to the sidewalls of the sound collection channel 200 or the windproof and sound-permeable member 30. This keeps the sound collection element 11 as far away from the oil as possible, thereby extending the service life of the sound collection element 11.Considering that the target noise (primarily from the fan system) that the active noise reduction system needs to collect is low-frequency noise, the sound propagation path within the sound collection device adopts a curved path design. This path attenuates high-frequency sounds (such as the high-frequency sound portion of wind noise and non-target noise such as the high-frequency sound components generated by the fan system) while having less impact on low-frequency sounds. Therefore, it is well suited to the propagation of low-frequency noise within the sound collection device, facilitating accurate collection of low-frequency noise by the sound collection element 11. This is primarily due to the longer wavelength of low-frequency noise, which can better adapt to the bends and irregular shapes of the pipe. When low-frequency noise propagates in a curved pipe, due to its longer wavelength, it is less likely to be obstructed or reflected by the pipe, and thus can be better propagated and diffused. High-frequency noise, on the other hand, has a shorter wavelength and is easily reflected and absorbed by the shape and curvature of the pipe, making it more difficult for it to propagate and diffuse within the pipe than low-frequency noise.

[0065] The oil-proof sound-permeable membrane 28 covers the first sound inlet 211 of the receiving groove 21 of the mounting frame 20, specifically, it is installed at 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-permeable membrane 28 and ensure its sealing after installation, the receiving groove 21 is further formed with an annular step portion 210 at the edge of its first sound inlet 211, and the oil-proof sound-permeable membrane 28 is arranged on the annular step portion 210. In order to ensure the oil-proof performance of the oil-proof sound-permeable membrane 28 and enable it to effectively transmit sound waves, the oil-proof sound-permeable membrane 28 of this embodiment is preferably a polyethylene film. Among them, Figure 3 As shown, there is a fourth distance, denoted as f, between the oil-proof sound-permeable membrane 28 and the sound collecting element 11. This fourth distance is denoted as f, with a value range of f ≥ 2 mm. This prevents contact with the sound collecting element 11 due to membrane vibration or micro-deformation, which could cause variations in sound transmission and affect sound collection accuracy. It should be understood that the fourth distance f between the oil-proof sound-permeable membrane 28 and the sound collecting element 11 should refer to the distance between the oil-proof sound-permeable membrane 28 and the microphone chip on the sound collecting element 28. In other words, the oil-proof sound-permeable membrane 28 may partially contact other components of the circuit board where the microphone chip resides (such as solder joints or fixing screws). The windproof sound-permeable member 30 does not directly contact the oil-proof sound-permeable membrane 28 to ensure oil-proofing. Specifically, there is a sixth distance, denoted as n, between the oil-proof sound-permeable membrane 28 and the main body of the windproof sound-permeable member 30 in the front-to-back direction. In order to avoid the oil-proof sound-permeable membrane 28 from contacting the windproof sound-permeable component 30 and affecting the sound transmission effect there, the sixth distance n between the oil-proof sound-permeable membrane 28 and the windproof sound-permeable component 30 should be greater than 0.1mm, preferably in the range of 0.5mm to 3mm.

[0066] To effectively slow airflow and eliminate airflow impact, the windproof and sound-permeable member 30 is a sleeve made of a porous, sound-absorbing material. For example, polyurethane foam or melamine foam can be used, and the porosity of the windproof and sound-permeable member 30 is greater than 70%. The windproof and sound-permeable member 30 of this embodiment not only prevents airflow from impacting the oil-proof sound-permeable membrane 28 and generating additional noise, but also, due to its porous nature, absorbs high-frequency components of sound energy, thereby filtering out noise signals. More specifically, the front sidewall of the windproof and sound-permeable member 30 abuts against the rear sidewall of the third sidewall 413 of the windshield 40, compressing the windproof and sound-permeable member 30. This compression increases the material density, effectively reducing the possibility of airflow pressure pulsations penetrating the windproof and sound-permeable member 30, thereby further enhancing the windproof effect.

[0067] The windproof and sound-permeable component 30 of this embodiment includes an extension section 301 extending upward from the top edge of the first sound inlet 211 of the accommodating groove 21, and the length of the extension section 301 of the windproof and sound-permeable component 30 is recorded as h, and the dimension of the first sound inlet 211 of the accommodating groove 21 in the up and down directions is m, wherein the value range of h / m is: 0.125≤h / m≤0.6. Since the sound propagation path of the sound collection device has a turning portion at the first sound inlet 211 of the receiving groove 21, if the upward extension length of the outer peripheral edge portion of the windproof and sound-permeable component 30 relative to the edge of the first sound inlet 211 of the receiving groove 21 is too short (such as h / m is less than 0.125), it will also be affected by a large amount of wind noise. After the above-mentioned parameter design, the windproof effect of the windproof and sound-permeable component is effectively guaranteed, and the accuracy of sound collection is avoided due to the short extension length of the outer peripheral edge of the windproof and sound-permeable component. Of course, considering the adverse effect of the windproof and sound-permeable component 30 on sound attenuation, the length of the extension section 301 of the windproof and sound-permeable component 30 should not be too large. If h / m is greater than 0.6, the sound will not be able to effectively meet the sound pressure requirements of the sound collection element 11 when it propagates to the receiving groove 21, thereby reducing the accuracy of noise collection.

[0068] To prevent the windproof and sound-permeable member 30 from contacting the oil continuously flowing down the sidewall of the air duct 10, a first spacing is provided between the windproof and sound-permeable member 30 and the rear sidewall of the air duct 10 after being installed on the mounting bracket 20. This first spacing is denoted as d, where the value range of d is d ≥ 4 mm. Similarly, to ensure windproofing, the main body of the windproof and sound-permeable member 30 has a front-to-back dimension (i.e., thickness) denoted as e, where the value range of e is 40 mm ≥ e ≥ 3 mm. Specifically, when e ≥ 3 mm, the windproof and sound-permeable member 30 can effectively prevent the airflow in the air duct from directly impacting the sound collecting element 11. Of course, considering the adverse effect of the windproof ball 30 (generally made of a porous material that is resistant to airflow disturbances and is sound-permeable) on sound attenuation, the front-to-back dimension (i.e., thickness) of the windproof and sound-permeable member 30 cannot be too large, and needs to be e ≤ 40 mm. At the same time, when the size (i.e., thickness) of the windproof and sound-permeable component 30 in the front-to-back direction is constant, the size d1 of the main body of the windproof and sound-permeable component 30 in the left-to-right direction must also be adapted thereto, that is, e / d1 needs to be reasonably limited, 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 main body of the windproof and sound-permeable component 30 is larger in the left-to-right direction, and the area of its upper part in contact with oil and dirt increases, which will directly affect the service life of the windproof and sound-permeable component 30. If e / d1 is too large (such as e / d1>0.5), it means that the main body of the windproof and sound-permeable component 30 is smaller in the left-to-right direction, which is not conducive to the transmission of sound from a larger lateral angle range above to the sound collection channel 200, affecting the accuracy of sound collection.

[0069] Due to the placement of the windproof, sound-permeable member 30 in the sound collection channel 200, there is a certain amount of loss in the sound propagation path from the second sound inlet 45 to the location of the sound collection element 11. This results in a loss of sound pressure. Therefore, it is necessary to ensure that a sufficient amount of the noise to be collected enters the receiving slot 21 of the mounting bracket 20 to be received by the sound collection element 11 and accurately capture the noise signal. Specifically, the principles of sound attenuation and compensation are as follows:

[0070] L w =L1-ΔL+10lgS0

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

[0072] When the sound reaches the top surface of the windproof and sound-permeable member 30, the sound pressure is L1;

[0073] Due to the weakening effect of the windproof and sound-permeable member 30, the sound pressure of the loss noise is ΔL;

[0074] an area S0 of a cross section at the second sound inlet 45 of the sound collecting channel 200;

[0075] Therefore, if the thickness of the windproof sound-permeable member 30 or the length thereof in the sound propagation path is too large, resulting in serious sound attenuation, the sound power L collected by the sound collecting element can be guaranteed by increasing S0. w Specifically, the ratio of the cross-sectional area S0 of the second sound inlet 45 of the sound collection channel 200 to the area S of the first sound inlet 211 at the front of the receiving slot 210 in this embodiment 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 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 installation of the windproof sound-permeable member. In this case, the sound collection accuracy is less than 80%. Therefore, the value range of S0 / S is S0 / S ≥ 0.18. This ensures that sufficient noise can pass through the sound collection channel 200 of the sound collection device to compensate for the sound pressure loss caused by the installation of the windproof sound-permeable member 30 and the bend in the sound propagation path. This ensures that the sound meets the sound pressure requirements of the sound collection element 11 when the sound propagates into the receiving slot 211, 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 generally fluctuates between 98% and 99%. In this case, the improvement in noise collection accuracy is minimal, and the improvement in active noise reduction is weak, but the installation space requirement for the sound collection device is larger. Therefore, the preferred range of S0 / S is: 0.18 ≤ S0 / S ≤ 1.5. More specifically, when 0.18 ≤ S0 / S < 0.3, the second sound inlet 45 is relatively large, which can make the sound collection channel more unobstructed, and the accuracy of sound collection is improved, generally reaching a range of 80% to 88%. When 0.3 ≤ S0 / S ≤ 1.5, the noise collection accuracy is optimal within this range, generally reaching a range of 91% to 98%. In addition, the installation space requirement for the sound collection device is relatively reasonable, and the space within the air duct 10 is not excessively occupied. Therefore, the preferred range of S0 / S is: 0.3 ≤ S0 / S ≤ 1.5.

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

[0077]

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

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

[0080]

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

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

[0083] The vertical dimension of the main body of the windproof and sound-permeable member 30 in this embodiment is denoted as g. In order to match the dimension of the first sound inlet 211 at the front of the receiving slot and ensure the windproof effect, 100mm ≥ g ≥ 10mm. The cross-sectional area of the main body of the windproof and sound-permeable member 30 adjacent to the second sound inlet 45 is S1. Figure 3 The cross section along the S1-S1 direction is the cross-sectional area of the main body of the windproof sound-permeable member 30 adjacent to the second sound inlet 45. Among them, g / 2+e / 2 represents the length of the sound propagation path in the windproof sound-permeable member. When the propagation path is long, the sound loss is greater. According to the sound propagation principle, L w =L1+101gS(L W (where L1 is the sound power, L2 is the sound pressure, and S is the area at the sound entrance) It can be seen that due to sound loss, the sound pressure decreases during sound propagation. As compensation, S1 should be increased to ensure that enough sound is collected by the sound collection element. Therefore, considering the sound propagation loss and compensation, the value of S1 / (g / 2+e / 2) should be greater than 8mm, and the preferred value range is: 10mm≤S1 / (g / 2+e / 2)≤15mm. If S1 / (g / 2+e / 2) is too small, such as S1 / (g / 2+e / 2)≤8, it means that the entrance area of the windproof and sound-permeable member near the end of the second sound entrance for effective sound transmission from top to bottom is small, and the amount of sound entering is insufficient to offset the adverse effects of the windproof and sound-permeable member 30 on sound loss in the vertical and front-to-back directions, thereby reducing the accuracy of sound collection 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 entrance area of the windproof and sound-permeable component 30 at the end position adjacent to the second sound entrance 45 for effective transmission of sound from top to bottom is large. Similarly, the area of the upper part of the windproof and sound-permeable component 30 that contacts oil and dirt increases, affecting the service life of the windproof and sound-permeable component 30.

[0084] In this embodiment, since the windproof and 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 and sound-permeable member 30 and the wind shield 40, the cross-sectional area S1 of the main body of the windproof and sound-permeable member 30 adjacent to the second sound inlet 45 is substantially consistent with the cross-sectional area S0 of the second sound inlet 45 of the sound collection channel 200.

[0085] The protective structure of this embodiment can realize the sound collection element to suppress wind noise while also ensuring that the noise signal passes through. According to the sound propagation theory, the protective structure is composed of sound mass M a Harmony C a It forms a low-pass filter, so it is necessary to make the cutoff frequency f of the structure itself c Greater than the upper frequency limit f of active noise reduction a , in order to accurately collect all the original noise frequencies that active noise reduction is concerned about.

[0086] in:

[0087]

[0088] V is the volume of the cavity in the protective structure, specifically the volume of the inner cavity enclosed by the oil-proof sound-permeable membrane and the inner wall of the mounting bracket's receiving groove; 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 pipe, which can be simplified to the minimum cross-sectional area of the pipe during the sound propagation process. In this embodiment, S0 is the cross-sectional area at the second sound inlet 45 of the sound collection channel 200;

[0090]

[0091] The applicant has found that due to the structural limitations of the range hood and the noise source and its propagation characteristics, the upper frequency limit f for active noise reduction of the range hood is a , should be 1200~2000Hz, so we can get:

[0092]

[0093] After simplification, it becomes:

[0094]

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

[0096] More specifically, in this embodiment, S0 is the cross-sectional area of the second sound inlet 45 of the sound collection channel 200, wherein 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 pipe, it can be simplified as follows:

[0099]

[0100] The size of the windproof and sound-permeable member 30 in the vertical direction is recorded as g, and the size of the main body of the windproof and sound-permeable member 30 in the front-to-back direction (ie, thickness) is recorded as e.

[0101] The above

[0102] Further simplification:

[0103]

[0104] In this embodiment, after the sound collection element 11 is installed in the receiving slot 21 of the mounting frame 20, an oil-proof sound-permeable membrane 28 is installed at the first sound inlet 211 thereof. A windproof sound-permeable member 30 is installed outside the first sound inlet 211, and a windshield 40 is installed outside the windproof sound-permeable member 30. This sound collection device utilizes these three layers of protection to effectively eliminate wind noise and prevent oil contamination. After the windshield 40 covers the windproof sound-permeable member 30, a second sound inlet 45 is reserved at the leeward end, communicating with the outside world. Due to airflow patterns, the flow near the windproof sound-permeable member 30 is low-speed and high-static-pressure, effectively reducing the adhesion of oil smoke to the windproof sound-permeable member 30. Furthermore, this allows noise to be effectively transmitted through the second sound inlet 45 to the receiving slot 21 of the mounting frame 20, ensuring the accuracy of noise data collection. On the other hand, considering the impact of the windproof and sound-permeable component 30 and the windproof cover 40 on the obstruction and loss of sound propagation, the ratio of the area S at the first sound entrance of the accommodating groove 21 to the area S0 at the second sound entrance 45 of the sound collection channel 200 is limited within a reasonable value range, which can ensure that enough noise passes through the 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, comprising an air duct 10 for smoke to pass through and an active noise reduction system provided in the air duct 10, wherein the active noise reduction system comprises the above-mentioned sound collection device.

[0106] Example 2

[0107] Figure 9 and Figure 10Another preferred embodiment of the sound collection device and range hood of the present invention is shown. The difference between this embodiment and embodiment 1 is 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, and the value range is: 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 to 14Another 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 extends vertically as a whole and comprises two sections arranged sequentially from top to bottom: a vertically extending upper section 201 (also known as the vertical section) and a lower section 202 (also known as the inclined section) that slopes downward toward the location of the receiving slot 21 of the mounting bracket 20. The upper section 201 of the sound collection channel 200 constitutes the main body of the sound collection channel 200. The opening of the first sound inlet 211 of the receiving slot 21 of the mounting bracket 20 is arranged obliquely upward toward B1, and its inclination direction is consistent with the inclination direction of the lower section 202 of the sound collection channel 200. More specifically, the first angle M formed between the opening direction B1 of the first sound inlet 211 and the extension direction of the upper section 201 of the sound collection channel 200 is also an acute angle, with a value range of 5°≤M<90°. Preferably, the value range of the first angle M is 30°≤M≤80°. The portions of the front wall of the mounting frame 20 corresponding to the upper section 201 and the lower section 202 of the sound collection channel 200 are respectively a vertical surface 20a and an inclined surface 20b. In addition, by Figure 12 It can be seen that the position of the vertical surface 20a of the mounting bracket 20 and the position of the accommodating groove 21 (that is, the position of the sound collecting element 11) are offset in the upper and lower directions, that is, the sound collecting element 11 is closer to the side wall of the air duct 10 for placing the mounting bracket 20, while the vertical surface 20a of the mounting bracket 20 is relatively far away from the side wall of the air duct 10 for placing the mounting bracket 20.

[0111] like Figure 12 As shown in FIG12 , the vertical surface 20a and the inclined surface 20b of the mounting bracket 20 of this embodiment intersect to form a second angle N. Due to the differences in viscosity, surface tension, and roughness of the wall material of the oil droplets themselves, the oil droplets are subjected to gravity, adhesion, surface tension, and friction on the inclined surface. When the inclined surface 20b has different inclination angles (i.e., the second angle N), the combined effect of different forces causes the movement of the oil droplets to be different. As shown in FIG12 , when the second angle N is 80° ≥ N ≥ 30°, since the adhesion and friction forces in the vertical direction resisting gravity are relatively small, the oil will flow down from the vertical surface 20a and accumulate at the corners to a certain extent, and then directly fall down. Due to the structural staggered design, the oil droplets will not drip onto the sound collecting element 11. However, as shown in FIG12 , 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 15It can be seen from FIG that the propagation path of the sound in the sound collecting device in this embodiment is a turning path of "first propagating downward and then obliquely upward", such as Figure 15 The path S shown in FIG. Since the turning angle of the sound propagation path of this embodiment is relatively large compared to that of (Example 1), especially, the opening of the first sound inlet 211 is set obliquely downward, it can achieve a better oil-proof purpose. However, the large turning angle also causes a certain loss of target noise, which has a certain impact on the accuracy of sound collection.

[0116] 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.

[0117] Example 5

[0118] Figure 17 and Figure 18 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 main body 203 of the sound collection channel 200 is a vertically extending linear channel. The lower portion of the sound collection channel 200 further includes a horizontally extending transverse section 204. The lower end of the main body of the sound collection channel 200 connects to one end of the transverse section 204. The first sound inlet 211 of the receiving slot 21 of the mounting frame 20 faces downward and connects to the other end of the transverse section 204 of the sound collection channel 200. The first angle M formed between the orientation of the first sound inlet 211 and the extension direction of the main body of the sound collection channel 200 is a straight angle, that is, the value range of the first angle M is 180°. Figure 17 As can be seen from FIG, the propagation path of the sound in the sound collection device of this embodiment is a turning path of "first propagating downward, then propagating horizontally, and finally propagating upward", as shown in FIG. Figure 17 The turning path S is shown in FIG. Since the sound collection channel of this embodiment is divided into two sections, one vertically and one horizontally, and the opening of the first sound inlet 211 faces downward, the sound propagation path within the sound collection device of this embodiment undergoes two "turns," thereby achieving good oil protection. However, the large turning angle and the large number of turns also result in a certain loss of target noise, which has a certain impact on the accuracy of sound collection.

[0119] 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.

Claims

1. A sound collection device, comprising a sound collection element (11), characterized in that: The invention also includes a shell (2), which defines a sound propagation channel. The sound propagation channel includes a first channel section and a second channel section that are connected in sequence and arranged at an angle. The sound collecting element (11) is located in the first channel section. The first channel section has a first sound inlet (211) that is connected to the second channel section. The second channel section has a second sound inlet (45) for external sound to enter. The second channel section is also provided with a windproof and sound-permeable member (30). The area at the first sound inlet (211) is recorded as S, and the area at the second sound inlet (45) is recorded 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, characterized in that: 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 range fumes extraction 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 leeward end of the shell (2), and the opening direction 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, characterized in that: The main body of the second channel section extends vertically, and the first angle formed by the opening direction of the first sound inlet (211) and the extension direction of the second channel section is recorded as M, and the value range of the first angle is: 5°≤M≤180°.

6. The sound collection device according to claim 5, characterized in that: The extension direction of the second channel section and the air duct (10) are both vertical, the opening of the second sound inlet (45) faces upward, and the opening direction of the first sound inlet (211) is perpendicular to the extension direction of the second channel section, that is, the first angle is a right angle.

7. The sound collection device according to claim 4, characterized in that: The shell (2) includes a mounting frame (20) and a windshield (40). A receiving groove (21) is provided on the front side wall of the mounting frame (20). The sound collecting 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 windshield (40) is arranged outside the mounting frame (20) and defines a sound collecting channel (200) between the windshield (40) and the mounting frame (20). The sound collecting channel (200) is connected to the first sound inlet (211) of the receiving groove (21) and is located in front of the receiving groove (21). The second channel section is defined by the leeward end of the windshield (40) and the mounting frame (20).

8. The sound collection device according to claim 7, characterized in that: The front side wall of the windproof and sound-permeable component (30) is in contact with 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, and the dimension of the portion of the windproof and sound-permeable component (30) adjacent to the second sound inlet (45) in the front-to-back direction is recorded as e, and the dimension in the left-to-right direction is recorded as d1, wherein the value range of e / d1 is: 0.2≤e / d1≤0.5, and the value range of e is 3mm≤e≤40mm.

10. The sound collection device according to claim 7, characterized in that: The second channel section extends vertically, and the windproof and sound-permeable component (30) includes an extension section extending upward from the top edge of the first sound inlet (211) of the accommodating groove (21), and the length of the extension section of the windproof and sound-permeable component (30) is recorded as h, and the size of the first sound inlet (211) of the accommodating groove (21) in the vertical direction is m, wherein 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 component (30) is a sound-permeable component made of porous sound-absorbing material.

12. A range hood comprising an air duct (10) for smoke to pass through and a sound collecting device arranged in the air duct (10), characterized in that: The sound collection device is the sound collection device according to any one of claims 1 to 11.

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

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