Noise reduction device and range hood

Abstract

The utility model relates to the technical field of kitchen electric products, and discloses a noise reduction device and a range hood. The noise reduction device comprises a connecting shell and a noise reduction structure, an oil smoke flow channel is formed in the connecting shell, and the inner cavity wall part of the connecting shell is sunken outwards to form an expansion cavity; the silencing structure is arranged in the expansion cavity, a sound absorption cavity is formed in the silencing structure, a noise inlet communicated with the sound absorption cavity is formed in the side, facing the oil smoke flow channel, of the silencing structure, a plurality of resonant cavities distributed in an array mode are formed in the side, deviating from the oil smoke flow channel, of the silencing structure, and the multiple resonant cavities are all communicated with the sound absorption cavity. After entering the oil smoke flow channel of the connecting shell, noise sound waves can enter the sound absorption cavity through the noise inlet when passing through the noise reduction structure, and can be reflected in the noise reduction cavity, so that the noise energy is reduced; in addition, sound waves can enter the resonant cavity through the silencing cavity to generate resonance, and the noise energy is further reduced.

Description

Technical Field

[0001] The utility model relates to the technical field of kitchen electrical products, in particular to a noise reduction device and a range hood. Background Art

[0002] A lot of oil smoke is generated during the cooking process. If you are in an oil smoke environment for a long time, it will damage your health. The oil smoke generated by cooking will adhere to the kitchen utensils and walls, making it difficult to clean. Therefore, most families will install a range hood to alleviate this situation. The range hood is a common kitchen appliance used to purify the kitchen environment. It quickly extracts the exhaust gas generated by the gas stove and the oil smoke generated during the cooking process and discharges them to the outside to purify the kitchen air and improve the user's cooking comfort.

[0003] In order to reduce the space occupied by the range hood in the kitchen, a top-mounted range hood is proposed in the prior art. The top-mounted range hood usually includes a chassis, a smoke collecting chamber and a connecting pipe. The chassis contains a fan and is located inside the ceiling, so that the chassis can be hidden and the kitchen can be kept beautiful and tidy. The smoke collecting chamber is located above the stove, one end of the connecting pipe is connected to the outlet of the smoke collecting chamber, and the other end of the connecting pipe is connected to the inlet of the chassis. When the fan is working, negative pressure can be generated in the chassis, the connecting pipe and the smoke collecting chamber, and the oil smoke generated by the stove can be discharged into the public exhaust duct after the smoke collecting chamber, the connecting pipe and the chassis in sequence, so as to purify the kitchen air. Since the fan is located in the chassis and is far away from the user's ears, the noise generated when using the range hood can be reduced to a certain extent. Specifically, compared with the traditional range hood, the noise of the fan of the top-mounted range hood can be reduced by 2dB when it is working, and the noise of the whole machine is expected to be reduced by 60dB.

[0004] However, the noise generated by the fan when it is working is generated by the impeller. The impeller rotates to generate aerodynamic noise, which is transmitted through the volute inlet of the fan, enters the smoke collecting chamber through the air duct, and then is transmitted to the user. In other words, the air duct is the main path for the transmission of aerodynamic noise. In the prior art, only sound-absorbing materials are arranged in the smoke collecting chamber to solve the problem of the loud noise generated by the fan when it is working. When the resistance of the public smoke exhaust air duct is large, the fan speed is large, and the range hood still produces loud noise.

[0005] Therefore, it is urgent to provide a noise reduction device to solve the above problems. Utility Model Content

[0006] Based on the above problems, the purpose of the present utility model is to provide a noise reduction device and a range hood, which can reduce the transmission of the range hood air duct noise while ensuring the smoking effect.

[0007] In order to achieve the above purpose, the utility model adopts the following technical solutions:

[0008] A noise reduction device, comprising:

[0009] A connecting shell is provided with an oil smoke flow channel in the connecting shell, and the inner cavity wall part of the connecting shell is recessed outward to form an expansion chamber;

[0010] The silencer structure is arranged in the expansion chamber, and a sound absorbing chamber is arranged in the silencer structure. A noise inlet connected to the sound absorbing chamber is arranged on the side of the silencer structure facing the oil fume flow channel, and a plurality of resonance chambers distributed in an array are arranged on the side of the silencer structure away from the oil fume flow channel, and the plurality of resonance chambers are all connected to the sound absorbing chamber.

[0011] As a preferred solution of the noise reduction device provided by the utility model, the noise reduction structure includes:

[0012] The silencer shell is a hollow structure, the hollow cavity of the silencer shell forms a sound-absorbing cavity, and the noise inlet is arranged on the side of the silencer shell facing the oil smoke flow channel;

[0013] Resonance protrusions: a plurality of resonance protrusions distributed in an array are protruded on the side of the silencer shell away from the oil smoke flow channel. The resonance protrusions are hollow structures, and the hollow cavities of the resonance protrusions form resonance cavities.

[0014] As a preferred solution of the noise reduction device provided by the utility model, the heights of the multiple resonant protrusions are not all equal.

[0015] As a preferred solution of the noise reduction device provided by the utility model, the sound-absorbing housing includes a micro-perforated plate and a mounting bracket which are arranged in parallel and at intervals in the expansion chamber, a sound-absorbing chamber is formed between the micro-perforated plate, the mounting bracket and the cavity wall of the expansion chamber, a noise inlet is arranged on the micro-perforated plate, and a resonant protrusion is arranged on the mounting bracket; or

[0016] The silencer shell includes a micro-perforated plate, a mounting bracket and a plurality of connecting side panels. The micro-perforated plate and the mounting bracket are arranged in parallel and at intervals. The plurality of connecting side panels are connected end to end in sequence and are arranged between the micro-perforated plate and the mounting bracket. The plurality of connecting side panels are all connected to the cavity wall of the expansion chamber. A noise inlet is arranged on the micro-perforated plate, and a resonant protrusion is arranged on the mounting bracket.

[0017] As a preferred solution of the noise reduction device provided by the utility model, expansion chambers are arranged on both sides of the connecting shell along the extension direction of the oil smoke flow channel, and a sound-absorbing structure is arranged in each expansion chamber.

[0018] As a preferred solution of the noise reduction device provided by the utility model, at least two expansion chambers are spaced apart on both sides of the connecting shell along the extension direction of the oil smoke flow channel, and a sound-absorbing structure is arranged in each expansion chamber.

[0019] The utility model also provides a range hood, comprising a smoke collecting chamber, a chassis and the above noise reduction device, wherein one end of the connecting shell of the noise reduction device is connected to the outlet of the smoke collecting chamber, and the other end of the connecting shell is connected to the inlet of the chassis.

[0020] As a preferred solution of the range hood provided by the utility model, one end of the connecting shell is detachably connected to the outlet of the smoke collecting chamber; and / or the other end of the connecting shell is detachably connected to the inlet of the chassis.

[0021] The number of the range hood noise reduction devices is at least two, and the at least two noise reduction devices are arranged in sequence along a direction perpendicular to the flow direction of the oil smoke.

[0022] The range hood also includes a connecting pipe, which is sleeved outside the noise reduction device.

[0023] The beneficial effects of the utility model are:

[0024] The noise reduction device provided by the utility model includes a connecting shell and a silencer structure. A fume flow channel is arranged in the connecting shell, and the inner cavity wall of the connecting shell is partially recessed outward to form an expansion chamber; the silencer structure is arranged in the expansion chamber, and a sound absorption chamber is arranged in the silencer structure. A noise inlet connected to the sound absorption chamber is arranged on the side of the silencer structure facing the fume flow channel, and a plurality of resonance chambers distributed in an array are arranged on the side of the silencer structure away from the fume flow channel, and the plurality of resonance chambers are all connected to the sound absorption chamber. After the noise sound wave enters the fume flow channel of the connecting shell, it can enter the sound absorption chamber through the noise inlet when passing through the silencer structure, and can be reflected in the silencer chamber, thereby reducing the noise energy; in addition, the sound wave can also enter the resonance chamber through the silencer chamber to resonate, further reducing the noise energy. The noise reduction device can reduce the transmission of the noise of the range hood air duct while ensuring the smoking effect, thereby improving the user experience.

[0025] The range hood provided by the utility model can reduce the transmission of noise in the range hood air duct while ensuring the smoking effect by applying the above-mentioned noise reduction device. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments of the present invention. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the contents of the embodiments of the present invention and these drawings without paying any creative work.

[0027] Figure 1 It is a structural schematic diagram of a form of a range hood provided by an embodiment of the utility model;

[0028] Figure 2 It is a perspective schematic diagram of the sound-absorbing structure provided by an embodiment of the utility model at a viewing angle;

[0029] Figure 3 is a perspective schematic diagram of the sound-absorbing structure provided by an embodiment of the utility model at another viewing angle;

[0030] Figure 4 It is a structural schematic diagram of another form of a range hood provided by an embodiment of the utility model.

[0031] In the figure:

[0032] 100-smoke collecting chamber; 200-chassis;

[0033] 1-connecting housing; 11-expansion chamber;

[0034] 2-silencing structure; 201-sound absorbing chamber; 21-silencing shell; 211-micro-perforated plate; 2111-noise inlet; 212-mounting bracket; 2121-noise outlet; 213-connecting side panel; 22-resonance protrusion. DETAILED DESCRIPTION

[0035] The present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It is to be understood that the specific embodiments described herein are only used to explain the present invention, rather than to limit the present invention. It should also be noted that, for ease of description, only the parts related to the present invention, rather than all structures, are shown in the accompanying drawings.

[0036] In the description of the present invention, unless otherwise clearly specified and limited, the terms "connected", "connected", and "fixed" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0037] In the present utility model, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may include that the first and second features are in direct contact, or may include that the first and second features are not in direct contact but are in contact through another feature between them. Moreover, a first feature being "above", "above" and "above" a second feature includes that the first feature is directly above and obliquely above the second feature, or simply indicates that the first feature is higher in level than the second feature. A first feature being "below", "below" and "below" a second feature includes that the first feature is directly below and obliquely below the second feature, or simply indicates that the first feature is lower in level than the second feature.

[0038] In the description of this embodiment, the terms "upper", "lower", "left", "right" and other directions or positional relationships are based on the directions or positional relationships shown in the drawings, and are only for the convenience of description and simplified operation, rather than indicating or implying that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore cannot be understood as a limitation of the present invention. In addition, the terms "first" and "second" are only used to distinguish in the description and have no special meaning.

[0039] Embodiment 1

[0040] Figure 1 The schematic diagram of the structure of the range hood provided in this embodiment is shown. Figure 2 A perspective schematic diagram of the sound-absorbing structure 2 provided in this embodiment at a viewing angle is shown. Figure 3 FIG. 2 shows a perspective schematic diagram of the sound-absorbing structure 2 provided in this embodiment at another viewing angle. Figure 1-Figure 3 As shown, this embodiment provides a noise reduction device, which includes a connecting shell 1 and a muffler structure 2. The connecting shell 1 is provided with an oil fume flow channel, and the inner cavity wall of the connecting shell 1 is partially recessed outward to form an expansion chamber 11; the muffler structure 2 is provided in the expansion chamber 11, and a sound absorption chamber 201 is provided in the muffler structure 2. The side of the muffler structure 2 facing the oil fume flow channel is provided with a noise inlet 2111 connected to the sound absorption chamber 201, and the side of the muffler structure 2 facing away from the oil fume flow channel is provided with a plurality of resonance chambers distributed in an array, and the plurality of resonance chambers are all connected to the sound absorption chamber 201. When the fan is started, after the generated noise sound wave enters the oil fume flow channel of the connecting shell 1, it can enter the sound absorption chamber 201 through the noise inlet 2111 when passing through the muffler structure 2, and can be reflected in the muffler chamber 201, thereby reducing the noise energy; in addition, the sound wave can also enter the resonance chamber through the muffler chamber 201 to resonate, further reducing the noise energy. The noise reduction device can reduce the transmission of range hood duct noise while ensuring the smoking effect, thereby improving the user experience.

[0041] Furthermore, there are multiple noise inlets 2111, and the multiple noise inlets 2111 are arranged in an array on the noise reduction structure 2. The multiple noise inlets 2111 will generate impedance to the noise passing through the noise reduction structure 2, thereby reducing the noise energy.

[0042] The silencer structure 2 includes a silencer shell 21 and a resonant protrusion 22. The silencer shell 21 is a hollow structure. The hollow cavity of the silencer shell 21 forms the above-mentioned sound absorption cavity 201. The noise inlet 2111 is arranged on the side of the silencer shell 21 facing the oil fume flow channel. A plurality of resonant protrusions 22 distributed in an array are protruded on the side of the silencer shell 21 away from the oil fume flow channel. The resonant protrusion 22 is a hollow structure. The hollow cavity of the resonant protrusion 22 forms the above-mentioned resonant cavity.

[0043] Specifically, the sound-absorbing housing 21 includes a micro-perforated plate 211, a mounting bracket 212 and a plurality of connecting side panels 213. The micro-perforated plate 211 and the mounting bracket 212 are arranged in parallel and at intervals. The plurality of connecting side panels 213 are connected end to end in sequence and are arranged between the micro-perforated plate 211 and the mounting bracket 212. The micro-perforated plate 211, the mounting bracket 212 and the plurality of connecting side panels 213 are arranged to form a hollow rectangular parallelepiped structure, and the hollow structure of the rectangular parallelepiped forms the above-mentioned sound-absorbing cavity 201. The micro-perforated plate 211 is provided with a plurality of noise inlets 2111 arranged in an array. The mounting bracket 212 is used to install the resonant protrusion 22, and the mounting bracket 212 is provided with a noise outlet 2121 corresponding to and connected to the resonant cavity one by one. This embodiment does not limit the aperture of the noise inlet 2111. Designers can select a noise inlet 2111 with a suitable aperture according to the results of experiments and simulations to achieve the best noise reduction effect.

[0044] Optionally, the heights of the plurality of resonant protrusions 22 are not all equal. This design enables the noise reduction structure 2 to eliminate noises of different frequency bands, further improving the noise reduction effect.

[0045] In this embodiment, the muffler housing 21 is an integrated structure to save the steps of assembling multiple parts and improve processing efficiency. Of course, in other embodiments, the micro-perforated plate 211, the mounting bracket 212 and the multiple connecting side panels 213 can also be separately set and connected by riveting, gluing, etc. The resonant protrusion 22 is formed separately and installed at the corresponding position of the mounting bracket 212 according to the preset arrangement according to actual needs. Optionally, the resonant protrusion 22 can be connected to the mounting bracket 212 by riveting, gluing, etc.

[0046] It is understandable that, in some other embodiments, the sound-absorbing shell 21 may not include the connecting side panel 213, and the micro-perforated plate 211 and the mounting bracket 212 are arranged in parallel and at intervals in the expansion chamber 11. The micro-perforated plate 211, the mounting bracket 212 and the cavity wall of the expansion chamber 11 are arranged to form the above-mentioned sound-absorbing cavity 201. This arrangement can also achieve the above-mentioned effect.

[0047] Optionally, the sound-absorbing structure 2 can be connected to the connecting shell 1 by means of clamping, bolting, riveting, bonding, etc., which ensures a stable connection and facilitates assembly.

[0048] Continue as Figure 1-Figure 2As shown, in some embodiments, expansion chambers 11 are provided on both sides of the connecting housing 1 along the extension direction of the oil fume flow channel, and a muffler structure 2 is provided in each expansion chamber 11. This arrangement can achieve a uniform noise reduction effect on the noise entering the oil fume flow channel. It has been verified by experiments and simulations that the noise reduction device of this arrangement can reduce narrowband noise.

[0049] Combine the following Figure 1-Figure 3 The design method of various parameters of the noise reduction device in this embodiment is introduced in detail.

[0050] The calculation formula of the noise reduction amount of the silencing structure 2 is:

[0051]

[0052] k = 2πf / c (2);

[0053]

[0054] In formula (1), TL is the noise reduction amount of the silencer structure 2; m is the expansion ratio; l0 is the length of the expansion chamber 11; k is a constant; f is the noise frequency; c is the propagation speed of sound waves in the air; S1 is the cross-sectional area of ​​the expansion chamber 11 along the horizontal direction; S2 is the cross-sectional area at the inlet of the connecting shell 1.

[0055] It can be seen from the above formula that the expansion ratio determines the noise reduction amount of the noise reduction structure 2 , and the length of the expansion chamber 11 determines the noise reduction frequency band of the noise reduction structure 2 .

[0056] For example, when the noise reduction structure 2 needs to reduce the noise of f=100 Hz and ensure the maximum noise reduction, the following formula needs to be satisfied:

[0057]

[0058] Where n = 0, 1, 2, 3, etc., and the appropriate length of the expansion chamber 11, l0 = 85 cm, is deduced. After the length l0 of the expansion chamber 11 is determined, the expansion ratio m is adjusted to achieve the best noise reduction. It should be noted that when formula (4) is satisfied, in formula (1), the following formula (5) is satisfied:

[0059] sin 2 (kl0)=1 (5).

[0060] After the length l0 of the expansion chamber 11 and the expansion ratio m are determined, the height of the resonant protrusion 22 also needs to be determined according to the following formula (6):

[0061]

[0062] Wherein, A is the cross-sectional area at the entrance of the resonant cavity of the resonant protrusion 22; V is the volume of the resonant cavity; l1 is the length of the entrance of the resonant cavity; and c is the propagation speed of sound waves in the air.

[0063] It can be seen from formula (6) that the larger the volume V of the resonant cavity, the larger the cross-sectional area A at the entrance of the resonant cavity, and the lower the resonant frequency.

[0064] It should be noted that the resonant protrusion 22 is not a cylindrical structure, but a bottle-shaped structure with a constricted mouth. The resonant protrusion 22 includes a resonant body and a resonant bottleneck connected in sequence. The cross-sectional area A at the entrance of the resonant cavity is the cross-sectional area at the resonant bottleneck, and the length l1 of the entrance of the resonant cavity is the length of the resonant bottleneck.

[0065] According to the above formulas (1) to (6), the size range of each parameter of the noise reduction device can be obtained. Designers can achieve noise reduction effects in different frequency bands or increase the noise reduction amount in the same frequency band by changing the size of each parameter. Among them, the sizes of the two expansion chambers 11 symmetrically arranged on both sides of the extension direction of the oil fume flow channel and the silencer structure 2 arranged in each expansion chamber 11 can be set to be the same to achieve an increase in the noise reduction amount in the same frequency band; or the sizes of the two expansion chambers 11 symmetrically arranged on both sides of the extension direction of the oil fume flow channel and the silencer structure 2 arranged in each expansion chamber 11 can be set to be different to achieve noise reduction processing for noises in different frequency bands.

[0066] Embodiment 2

[0067] Figure 4 FIG. 2 shows a schematic diagram of the structure of the range hood provided in this embodiment. Figure 4 Combined with Figure 2 As shown, this embodiment provides a noise reduction device, the specific structure of which is roughly the same as that of the first embodiment, except that at least two expansion chambers 11 are arranged at intervals on both sides of the connecting shell 1 along the extension direction of the oil fume flow channel, and each expansion chamber 11 is provided with a silencer structure 2. With this arrangement, the noise will undergo multiple levels of noise reduction in the process of passing through the oil fume flow channel, thereby improving the noise reduction effect. It has been verified through experiments and simulations that the noise reduction device with this arrangement can reduce broadband noise, compared with Figure 1 The noise reduction effect is better.

[0068] In this embodiment, the number of expansion chambers 11 provided in the connection housing 1 is four, and the four expansion chambers 11 are divided into two expansion chamber groups in pairs, and the two expansion chamber groups are arranged at intervals along the extension direction of the oil smoke flow channel, and the two expansion chambers 11 in each expansion chamber group are symmetrically arranged on both sides along the extension direction of the oil smoke flow channel, while ensuring the noise reduction effect, reducing the number of sound absorbing structures 2, thereby reducing the manufacturing cost. Of course, in other embodiments, the number of expansion chambers 11 provided in the connection housing 1 can also be six, eight, etc., and this embodiment does not limit this.

[0069] In this embodiment, the various parameter dimensions of the multiple expansion chambers 11 and the muffler structure 2 in each expansion chamber 11 can be calculated according to formulas (1) to (6) in the first embodiment, which will not be described in detail in this embodiment.

[0070] Embodiment 3

[0071] Continue as Figure 1 As shown, this embodiment provides a range hood, which includes a smoke collecting chamber 100, a case 200 and a noise reduction device (the noise reduction device provided in the first embodiment or the second embodiment can be used), a fan is placed in the case 200, one end of the noise reduction device is connected to the outlet of the smoke collecting chamber 100, and the other end of the noise reduction device is connected to the inlet of the case 200, and the smoke collecting chamber 100 is located above the stove. When the fan is working, negative pressure can be generated in the case 200, the noise reduction device and the smoke collecting chamber 100, and the oil smoke generated by the stove can be discharged into the public exhaust duct after passing through the smoke collecting chamber 100, the noise reduction device and the case 200 in sequence, so as to achieve the effect of purifying the kitchen air.

[0072] The range hood in this embodiment mainly refers to a ceiling-mounted range hood, that is, the chassis 200 is located inside the ceiling, which can hide the chassis 200 and keep the kitchen beautiful and tidy, and can keep the fan away from human ears, reducing the noise generated when using the range hood to a certain extent. Of course, in other embodiments, the range hood can also be an ordinary range hood with the chassis 200 placed outside the ceiling.

[0073] Furthermore, the range hood further comprises a connecting pipe, which is sleeved outside the noise reduction device to protect the noise reduction device and maintain the overall appearance of the range hood. Of course, in other embodiments, the connecting pipe may not be provided, and this embodiment is not limited to this.

[0074] Optionally, one end of the connecting shell 1 can be detachably connected to the outlet of the smoke collecting chamber 100; the other end of the connecting shell 1 can be detachably connected to the inlet of the chassis 200. Specifically, the connecting shell 1 is connected to the smoke collecting chamber 100 by screws, and the connecting shell 1 is connected to the chassis 200 by screws. The screw connection has the advantages of stable connection, convenient processing and convenient disassembly. Of course, in other embodiments, one end of the connecting shell 1 can also be plugged into the outlet of the smoke collecting chamber 100, and the other end of the connecting shell 1 can be plugged into the inlet of the chassis 200, which can also achieve the above effect.

[0075] To further improve the noise reduction effect, in this embodiment, the number of noise reduction devices is at least two, and at least two noise reduction devices are arranged in sequence along a direction perpendicular to the direction of oil smoke flow, which is equivalent to connecting multiple noise reduction devices in parallel between the smoke collecting chamber 100 and the chassis 200.

[0076] Note that the above are only preferred embodiments of the present invention and the technical principles used. Those skilled in the art will understand that the present invention is not limited to the specific embodiments described herein, and that various obvious changes, readjustments and substitutions can be made by those skilled in the art without departing from the scope of protection of the present invention. Therefore, although the present invention is described in more detail through the above embodiments, the present invention is not limited to the above embodiments, and may include more other equivalent embodiments without departing from the concept of the present invention, and the scope of the present invention is determined by the scope of the appended claims.

Claims

1. A noise reduction device, characterized in that: include: A connecting shell (1), wherein a fume flow channel is arranged in the connecting shell (1), and an inner cavity wall portion of the connecting shell (1) is recessed outwards to form an expansion chamber (11); A silencer structure (2) is arranged in the expansion chamber (11), a sound absorption chamber (201) is arranged in the silencer structure (2), a noise inlet (2111) connected to the sound absorption chamber (201) is arranged on the side of the silencer structure (2) facing the oil fume flow channel, and a plurality of resonance chambers distributed in an array are arranged on the side of the silencer structure (2) facing away from the oil fume flow channel, and the plurality of resonance chambers are all connected to the sound absorption chamber (201).

2. The noise reduction device according to claim 1, characterized in that: The noise reduction structure (2) comprises: A silencer shell (21), the silencer shell (21) being a hollow structure, the hollow cavity of the silencer shell (21) forming the sound absorption cavity (201), and the noise inlet (2111) being arranged on a side of the silencer shell (21) facing the oil smoke flow channel; A resonant protrusion (22), wherein a plurality of the resonant protrusions (22) distributed in an array are protruded on the side of the muffler housing (21) facing away from the oil smoke flow channel, the resonant protrusion (22) being a hollow structure, and the hollow cavity of the resonant protrusion (22) forming the resonant cavity.

3. The noise reduction device according to claim 2, characterized in that: The heights of the plurality of resonant protrusions (22) are not all equal.

4. The noise reduction device according to claim 2, characterized in that: The sound-absorbing housing (21) comprises a micro-perforated plate (211) and a mounting bracket (212) which are arranged in parallel and at intervals in the expansion chamber (11); the micro-perforated plate (211), the mounting bracket (212) and the cavity wall of the expansion chamber (11) enclose the sound-absorbing cavity (201); the micro-perforated plate (211) is provided with the noise inlet (2111); and the resonant protrusion (22) is provided on the mounting bracket (212); or The sound-absorbing shell (21) comprises a micro-perforated plate (211), a mounting bracket (212) and a plurality of connecting side plates (213); the micro-perforated plate (211) and the mounting bracket (212) are arranged in parallel and at intervals; the plurality of connecting side plates (213) are connected end to end in sequence and are arranged between the micro-perforated plate (211) and the mounting bracket (212); the plurality of connecting side plates (213) are all connected to the cavity wall of the expansion chamber (11); the noise inlet (2111) is arranged on the micro-perforated plate (211); and the resonant protrusion (22) is arranged on the mounting bracket (212).

5. The noise reduction device according to any one of claims 1 to 4, characterized in that: The expansion chambers (11) are arranged on both sides of the connecting shell (1) along the extension direction of the oil smoke flow channel, and the sound-absorbing structure (2) is arranged in each expansion chamber (11).

6. The noise reduction device according to any one of claims 1 to 4, characterized in that: At least two expansion chambers (11) are arranged at intervals on both sides of the connecting shell (1) along the extension direction of the oil smoke flow channel, and each expansion chamber (11) is provided with the muffler structure (2).

7. A range hood, characterized in that: It comprises a smoke collecting chamber (100), a chassis (200) and a noise reduction device according to any one of claims 1 to 6, wherein one end of a connecting shell (1) of the noise reduction device is connected to an outlet of the smoke collecting chamber (100), and the other end of the connecting shell (1) is connected to an inlet of the chassis (200).

8. The range hood according to claim 7, characterized in that: One end of the connecting shell (1) is detachably connected to the outlet of the smoke collecting chamber (100); and / or the other end of the connecting shell (1) is detachably connected to the inlet of the chassis (200).

9. The range hood according to claim 7, characterized in that: The number of the noise reduction devices is at least two, and at least two of the noise reduction devices are arranged in sequence along a direction perpendicular to the flow direction of the oil smoke.

10. The range hood according to any one of claims 7 to 9, characterized in that: The range hood further comprises a connecting pipe, and the connecting pipe is sleeved outside the noise reduction device.

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