Centrifugal fan, fresh air module, air conditioner indoor unit and air conditioner

Abstract

The invention discloses a centrifugal fan, a fresh air module, an air conditioner indoor unit and an air conditioner, and belongs to the technical field of fan equipment.The centrifugal fan comprises a volute and a sound absorption structure, an air flue is arranged in the volute, the volute is provided with an air inlet, a plurality of through holes are formed in the side, away from the air inlet, of the volute, and the sound absorption structure is connected to the side wall where the through holes are located; the sound absorption structure comprises a plurality of sound attenuation cavities arranged at intervals, the multiple layers of sound attenuation cavities are arranged in the radial direction of the volute, and each layer is provided with at least one sound attenuation cavity, so that the sound attenuation cavities are distributed in the side wall of the volute, and the sound attenuation cavities communicate with the through holes in a one-to-one correspondence mode. Sound waves can enter the noise reduction cavity through the through holes, the noise reduction effect can be achieved through the noise reduction cavity, and noise generated by the centrifugal fan is effectively reduced; the volume of the centrifugal fan is not obviously increased by the sound absorption structure, the installation compatibility is higher, the filling of resistive noise elimination materials is not needed, and the safety and the reliability are higher.

Description

Technical Field

[0001] The present invention relates to the technical field of air conditioning equipment, and in particular to a centrifugal fan, a fresh air module, an indoor air conditioner, and an air conditioner. Background Art

[0002] The fresh air module of the indoor air conditioner uses a centrifugal fan to send air from the outside to the inside. At present, the main noise reduction means of the centrifugal fan are to wrap the outside of the fan or expand the volute to fill sound-absorbing cotton and other resistive sound-absorbing materials. The above means will significantly increase the volume of the centrifugal fan, thereby reducing the installation compatibility of the centrifugal fan. The resistive sound-absorbing materials are also prone to bring derivative safety and reliability problems, which is not conducive to the stable operation of the centrifugal fan. Summary of the Invention

[0003] The present invention aims to solve at least one of the technical problems existing in the prior art. For this reason, the present invention provides a centrifugal fan applicable to an indoor air conditioner, which has an effective noise reduction effect and higher safety and reliability.

[0004] The present invention also provides a fresh air module, an indoor air conditioner, and an air conditioner applying the above centrifugal fan.

[0005] The centrifugal fan according to the first aspect of the embodiments of the present invention includes a volute and a sound-absorbing structure. A air duct is provided in the volute. The volute is provided with an air inlet. A plurality of through holes are provided on a side of the volute away from the air inlet. The air inlet and the plurality of through holes are both communicated with the air duct; the sound-absorbing structure is connected to the volute and is located on the side wall where the through holes are located. The sound-absorbing structure includes a plurality of sound-absorbing cavities arranged at intervals. The plurality of sound-absorbing cavities are arranged in multiple layers along the radial direction of the volute, and each layer has at least one sound-absorbing cavity. The sound-absorbing cavity is in one-to-one correspondence and communication with the through hole.

[0006] The centrifugal fan according to the embodiments of the present invention has at least the following beneficial effects:

[0007] By adding a sound-absorbing structure to the volute of the centrifugal fan, a plurality of through holes communicated with the air duct are provided on the side of the volute away from the air inlet. The sound-absorbing structure is connected to the side wall where the through holes are located. The sound-absorbing structure includes a plurality of sound-absorbing cavities arranged at intervals. The plurality of sound-absorbing cavities are arranged in multiple layers along the radial direction of the volute, and each layer has at least one sound-absorbing cavity. In this way, the sound-absorbing cavities are arranged on the side wall of the volute, and the sound-absorbing cavities are in one-to-one correspondence and communication with the through holes; when the centrifugal fan works, sound waves will enter the sound-absorbing cavities through the through holes, and the sound-absorbing cavities can play a role in noise reduction, effectively reducing the noise generated by the centrifugal fan; the sound-absorbing structure does not significantly increase the volume of the centrifugal fan, has higher installation compatibility, and does not need to be filled with resistive sound-absorbing materials, so the safety and reliability are higher, and the centrifugal fan runs more stably.

[0008] According to some embodiments of the present invention, the centrifugal fan further includes:

[0009] A motor is arranged on a side of the volute opposite to the air inlet;

[0010] A wind wheel, located in the wind duct and connected to the motor;

[0011] The sound absorbing structure is located on the side of the volute away from the motor, each layer has a plurality of silencer cavities arranged in an annular structure along the circumference of the volute, and the annular structure is coaxially arranged with the wind wheel.

[0012] According to some embodiments of the present invention, along the radial direction of the volute, the outer diameter of the outermost annular structure is greater than or equal to the diameter of the wind wheel, and the inner diameter of the innermost annular structure is greater than or equal to the diameter of the motor.

[0013] According to some embodiments of the present invention, the width of the muffler cavity is w c , there are isolation ribs between adjacent silencing cavities, the thickness of the isolation ribs is h, the outer diameter of the outermost annular structure is D, the inner diameter of the innermost annular structure is d, the number of layers of the silencing cavity is N, and N is a positive integer greater than or equal to 4, satisfying: Nw c +(N+1)h=0.5(Dd).

[0014] According to some embodiments of the present invention, along the direction away from the axis of the wind wheel, the number of layers of each layer of the annular structure is a level, the level is x and x is greater than or equal to 1 and less than or equal to N, and the inner diameter of each layer of the annular structure satisfies: r 1 =(x-1)w c +xh, outer diameter meets: r 2 =xw c +xh.

[0015] According to some embodiments of the present invention, the width of the silencing cavity ranges from 4 mm to 14 mm, and the thickness of the isolation rib ranges from 0.6 mm to 2.5 mm.

[0016] According to some embodiments of the present invention, at least a portion of the muffler cavity is bent along the radial direction of the volute to form a bent portion, and the bent portion is arranged side by side with the muffler cavity of an adjacent layer.

[0017] According to some embodiments of the present invention, at least two sound absorbing structures are provided, and at least two of the sound absorbing structures are arranged sequentially in a direction away from the air duct, and the silencer cavities of all the sound absorbing structures are connected to the through holes in a one-to-one correspondence.

[0018] According to some embodiments of the present invention, at least two of the sound absorption structures include a first sound absorption structure and a second sound absorption structure. The second sound absorption structure is disposed on a side of the first sound absorption structure away from the volute. A partition is provided between the first sound absorption structure and the second sound absorption structure. The partition is provided with a plurality of openings, and the openings are in one-to-one correspondence and communication with the sound absorption cavities in the second sound absorption structure. The first sound absorption structure is further provided with a channel for communicating the openings with the through holes.

[0019] According to some embodiments of the present invention, at least part of the sound absorption cavities are bent along the radial direction of the volute to form a bent portion. The bent portion is arranged side by side with the sound absorption cavities of adjacent layers. Each sound absorption structure is provided with at least 10 sound absorption cavities with a length greater than or equal to 25 mm.

[0020] According to some embodiments of the present invention, the sound absorption cavities in the first sound absorption structure and the sound absorption cavities in the second sound absorption structure have the same height, and the height is 2 mm to 20 mm. The thickness range of the partition is 1 mm to 2.5 mm.

[0021] According to some embodiments of the present invention, there is a high-speed air flow area in the volute. The high-speed air flow area includes:

[0022] A fan-shaped area, with the central axis of the wind wheel as the center of the circle, a straight line drawn from the center of the circle is tangent to the volute tongue of the volute, and the area formed by rotating the line segment between the tangent point and the center of the circle by 60° along the rotation direction of the wind wheel;

[0023] An annular area, with the central axis of the wind wheel as the center of the circle, and an area formed with a first length as the inner diameter and a second length as the outer diameter. The ratio of the first length to the diameter of the wind wheel is 0.9, and the ratio of the second length to the diameter of the wind wheel is 1.1;

[0024] On the projection plane perpendicular to the axial direction of the wind wheel, the number of the through holes located within the projection of the high-speed air flow area is less than or equal to 15% of the total number of the through holes.

[0025] According to some embodiments of the present invention, the maximum width of the through hole is greater than or equal to 1 / 4 of the width of the sound absorption cavity and less than or equal to the width of the sound absorption cavity.

[0026] According to some embodiments of the present invention, the through hole is a square hole with a length of 1 mm to 5 mm, or the through hole is a fan-shaped hole with an arc length of 1 mm to 5 mm.

[0027] According to a second aspect of the embodiments of the present invention, a fresh air module includes:

[0028] The centrifugal fan described in the embodiments of the first aspect above;

[0029] An air guiding part, which is connected to the outside of the volute and covers the air inlet, and the air guiding part is provided with an air inlet passage communicating with the air inlet.

[0030] The fresh air module according to the embodiment of the present invention has at least the following beneficial effects:

[0031] The fresh air module adopts the centrifugal fan of the embodiment. The centrifugal fan is communicated with the outside through the air guiding part, and outdoor air can enter the centrifugal fan through the air inlet passage, and the centrifugal fan sends air to the room; a sound absorption structure is added to the volute, and the sound absorption structure can play a role in noise reduction, effectively reducing the noise generated by the centrifugal fan; the sound absorption structure does not significantly increase the volume of the centrifugal fan, has higher installation compatibility, and does not need to be filled with resistive sound absorption materials, so the safety and reliability are higher, which is beneficial to improving the operation stability of the fresh air module.

[0032] The air conditioner indoor unit according to the third aspect of the embodiment of the present invention includes the fresh air module described in the second aspect of the embodiment.

[0033] The air conditioner indoor unit according to the embodiment of the present invention has at least the following beneficial effects:

[0034] The air conditioner indoor unit adopts the fresh air module of the embodiment. The centrifugal fan of the fresh air module adds a sound absorption structure to the volute. The sound absorption structure does not significantly increase the volume of the centrifugal fan, and does not need to be filled with resistive sound absorption materials, so the safety and reliability are higher, which is beneficial to improving the operation stability of the air conditioner indoor unit.

[0035] The air conditioner according to the fourth aspect of the embodiment of the present invention includes the air conditioner indoor unit described in the second aspect of the above embodiment.

[0036] Since the air conditioner adopts all the technical solutions of the above all embodiments, it has at least all the beneficial effects brought by the technical solutions of the above embodiments, which will not be elaborated one by one here.

[0037] Other features and advantages of the present invention will be described in the subsequent description, and part of them will become obvious from the description, or will be understood by implementing the present invention. Description of the Drawings

[0038] Figure 1 is an exploded structural view (right side view) of the fresh air module in an embodiment of the present invention;

[0039] Figure 2 is an exploded structural view (left side view) of the fresh air module in an embodiment of the present invention;

[0040] Figure 3 is a three-dimensional schematic view of the first sound absorption structure in an embodiment of the present invention;

[0041] Figure 4 is the front schematic view of the first sound absorption structure in an embodiment of the present invention;

[0042] Figure 5 is Figure 4 the partial enlarged structural schematic view of part A in

[0043] Figure 6 is the three-dimensional schematic view of the second sound absorption structure in an embodiment of the present invention;

[0044] Figure 7 is the front schematic view of the second sound absorption structure in an embodiment of the present invention;

[0045] Figure 8 is Figure 7 the partial enlarged structural schematic view of part C in

[0046] Figure 9 is Figure 4 the partial sectional schematic view in the B-B direction of

[0047] Figure 10 is the outer side structural schematic view of the right housing in an embodiment of the present invention;

[0048] Figure 11 is the inner side structural schematic view of the right housing in an embodiment of the present invention;

[0049] Figure 12 is the schematic diagram of the sound absorption rate - frequency simulation result of the sound absorption structure in an embodiment of the present invention.

[0050] Reference numerals:

[0051] Centrifugal fan 100; volute 101; left housing 110; right housing 120; through hole 121; right side wall 122; fixed seat 123; air outlet 130; volute tongue 140; high-speed air flow area 150; fan-shaped area 151; annular area 152;

[0052] Sound absorption structure 200; first sound absorption structure 201; second sound absorption structure 202; sound insulation cavity 210; bending part 211; first-stage cavity 212; second-stage cavity 213; isolation rib 220; central hole 230; partition plate 240; opening 241; sealing plate 250; channel 260;

[0053] Air guiding part 300; air inlet channel 310;

[0054] Fresh air module 1000. Detailed implementation manners

[0055] In order to more clearly understand the above-mentioned objects, features, and advantages of the present invention, the present invention will be further described in detail below in conjunction with the accompanying drawings and specific embodiments. It should be noted that, without conflict, the embodiments of the present application and the features in the embodiments can be combined with each other.

[0056] The embodiments of the present invention will be described in detail below. The examples of the embodiments are shown in the accompanying drawings, where the same or similar reference numerals represent the same or similar elements or elements with the same or similar functions from beginning to end. The embodiments described below by referring to the accompanying drawings are exemplary and are only used to explain the present invention and should not be construed as a limitation of the present invention.

[0057] In the description of the present invention, it should be understood that the orientation or positional relationships indicated by terms such as "front", "rear", "upper", "lower", "axial direction", "circumferential direction", "radial direction", etc. are based on the orientation or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus should not be construed as a limitation of the present invention.

[0058] In the description of the present invention, if terms such as "first" and "second" are described, they are only for the purpose of distinguishing technical features, and should not be construed as indicating or implying relative importance or implicitly indicating the quantity of the indicated technical features or implicitly indicating the sequence relationship of the indicated technical features.

[0059] In the description of the present invention, it should be noted that terms such as "set", "installed", "connected", etc. should be understood in a broad sense, and those skilled in the art can reasonably determine the specific meanings of the above terms in the present invention in combination with the specific content of the technical solution.

[0060] The technical solution of the present invention will be clearly and completely described below in conjunction with the accompanying drawings. Obviously, the following described embodiments are some embodiments of the present invention, not all embodiments.

[0061] The fresh air module is usually composed of accessories such as a fan and a pipeline. The outdoor air is purified by the fan and introduced into the room, and it is applicable to the indoor unit of an air conditioner. The fresh air module of the indoor unit of an air conditioner usually uses a centrifugal fan for air supply. Since noise is generated when the centrifugal fan operates, in the related art, in order to achieve the purpose of noise reduction, a resistive sound-absorbing material such as sound-absorbing cotton is wrapped outside the centrifugal fan, or the volute is enlarged to fill the above-mentioned resistive sound-absorbing material. However, the above means will significantly increase the volume of the centrifugal fan, thereby reducing the installation compatibility of the centrifugal fan, and the resistive sound-absorbing material is prone to bring derivative safety and reliability problems, which is not conducive to the stable operation of the centrifugal fan.

[0062] In the related art, a traditional perforated muffler can also be used to reduce the noise of a centrifugal fan, which will also significantly increase the volume of the fan. Moreover, since the main noise frequency in the normal working state of most centrifugal fans is around 1000 Hz, the noise reduction performance of the traditional perforated muffler in this frequency range is not ideal.

[0063] To solve the above problems, an embodiment of the present invention provides a centrifugal fan 100, which is applicable to a fresh air module 1000. The following will refer to Figures 1 to 11 As shown, taking the fresh air module 1000 of an air conditioner indoor unit as an example, the centrifugal fan 100 of the embodiment of the present invention will be introduced specifically.

[0064] Refer to Figure 1 As shown, the centrifugal fan 100 provided by the embodiment of the present invention includes a volute 101, an impeller and a motor. The volute 101 is provided with an air inlet and an air outlet 130, and a air duct communicating the air inlet and the air outlet 130 is arranged in the volute 101. Among them, the air inlet is located on one side of the volute 101 along the width direction of the volute 101, the motor is installed on the other side, and the impeller is located in the air duct and connected to the motor. Taking Figure 1 the direction shown as the reference direction, the air inlet is opened on the left side wall of the volute 101, the motor is connected to the inner wall on the right side of the volute 101, and the air outlet 130 is located on the upper side of the volute 101.

[0065] It can be understood that in the embodiment, the impeller is a centrifugal impeller (not shown in the drawings), and the axial direction of the impeller is consistent with the width direction of the volute 101. That is to say, the air inlet and the motor are respectively located on both sides of the impeller along its axial direction. During operation, the motor drives the impeller to rotate to drive the air flow to enter the volute 101 from the air inlet and flow along the air duct to the air outlet 130.

[0066] The centrifugal fan 100 of the embodiment of the present invention is applicable to the fresh air module 1000. The fresh air module 1000 can introduce outdoor air into the room through the centrifugal fan 100 to update the indoor air. The fresh air module 1000 can be used independently or applied to an air conditioner indoor unit. While the air conditioner indoor unit adjusts the indoor temperature, it can provide fresh air to the room, thereby improving the indoor air quality. It should be noted that the air conditioner indoor unit can be a wall-mounted unit, a cabinet-type unit, etc.

[0067] Refer to Figure 1 and Figure 2As shown in the figure, the centrifugal fan 100 according to the embodiment of the present invention further includes a sound-absorbing structure 200. The sound-absorbing structure 200 is connected to the volute 101 and is located on the side of the volute 101 away from the motor, that is, the sound-absorbing structure 200 is located on the outer wall of the right side of the volute 101. In this way, the air inlet, the impeller, the motor and the sound-absorbing structure 200 are all arranged along the axial direction of the impeller. In the embodiment, a plurality of through holes 121 are provided on the right side wall 122 of the volute 101. The plurality of through holes 121 are respectively communicated with the air duct. The sound-absorbing structure 200 includes a plurality of sound-absorbing cavities 210. The plurality of sound-absorbing cavities 210 are in one-to-one correspondence and communication with the plurality of through holes 121. The sound-absorbing cavity 210 plays a role in noise reduction. The noise of the centrifugal fan 100 can be reduced through the sound-absorbing cavity 210, thereby improving the noise environment of the fresh air module 1000.

[0068] In the embodiment, the plurality of sound-absorbing cavities 210 are arranged on the outer side wall of the volute 101 according to a certain rule, and the adjacent sound-absorbing cavities 210 are arranged at intervals, that is, each sound-absorbing cavity 210 is an independent cavity structure. Specifically, the plurality of sound-absorbing cavities 210 are arranged in multiple layers along the radial direction of the volute 101, and each layer has at least one sound-absorbing cavity 210, so that the plurality of sound-absorbing cavities 210 can be distributed on the outer side wall of the volute 101. The sound-absorbing cavity 210 itself has a noise reduction effect and does not need to be filled with resistive sound-absorbing materials, effectively solving the safety and reliability problems caused by the resistive sound-absorbing materials, which is beneficial to the stable operation of the centrifugal fan 100.

[0069] For example, the sound-absorbing structure 200 can be arranged in four layers, each layer has one sound-absorbing cavity 210, and each sound-absorbing cavity 210 can have different lengths, and can be arranged in a stacked structure in the shape of a triangle, a sector or other shapes; it can also be that each layer has a plurality of sound-absorbing cavities 210, and the plurality of sound-absorbing cavities 210 are arranged along the circumferential direction of the volute 101, so that a plurality of sound-absorbing cavities 210 can be reasonably arranged on the outer side wall of the volute 101.

[0070] Refer to Figure 1 As shown in the figure, it should be noted that the volute 101 includes a left housing 110 and a right housing 120. The left housing 110 and the right housing 120 are connected to form the volute 101 and define an air duct. A circumferential wall is formed at the connection position between the left housing 110 and the right housing 120. The air inlet is provided on the left housing 110, the motor is installed on the right housing 120, and the through hole 121 is formed on the bottom wall of the right housing 120.

[0071] It can be understood that the shapes of both sides of the volute 101 along its width are close to circular. Since the motor is installed at the middle position of the right housing 120 and the wind wheel is coaxially arranged with the motor, the position of the central axis of the wind wheel is the same as or close to the position of the central axis of the volute 101. Therefore, the radial direction of the volute 101 can be understood as the radial direction of the wind wheel or the motor. A plurality of sound absorption cavities 210 are arranged in a direction away from the central axis on the plane where the right side wall 122 is located, forming a multi-layer sound absorption cavity 210 structure.

[0072] In addition, the circumferential direction of the volute 101 can be understood as the circumferential direction of the wind wheel or the motor. That is to say, a plurality of sound absorption cavities 210 are arranged on the outer wall surface of the volute 101 in a direction perpendicular to the central axis. Without increasing the volume of the volute 101, only slightly increasing the overall volume of the centrifugal fan 100, it has a higher installation compatibility with the air conditioner indoor unit. Under the condition of the same air volume, the centrifugal fan 100 of the embodiment of the present invention can have a better noise reduction effect.

[0073] For example, the sound absorption structure 200 is provided with 8 sound absorption cavities 210. The sound absorption cavities 210 are distributed in two layers along the radial direction of the volute 101, and each layer has 4 sound absorption cavities 210. The 4 sound absorption cavities 210 are arranged along the circumferential direction of the volute 101, and are the first layer and the second layer in sequence along the direction away from the axis of the volute 101. It can be understood that the more the number of layers of the sound absorption cavities 210, the larger the plane occupied by them along the radial direction; the more the number of sound absorption cavities 210 in each layer, the larger the plane occupied by them along the circumferential direction. In this way, the sound absorption cavities 210 will not significantly increase the axial dimension of the centrifugal fan 100, and the layout is more reasonable. The specific number of the sound absorption cavities 210 is set according to actual requirements.

[0074] Refer to Figure 2 As shown, the number of through holes 121 is the same as the number of sound absorption cavities 210, and the distribution positions of the through holes 121 correspond to the positions of the sound absorption cavities 210 one by one, so that each sound absorption cavity 210 can communicate with the corresponding through hole 121. Specifically, a plurality of through holes 121 are distributed along the radial and circumferential directions of the volute 101. The front end or the tail end of each sound absorption cavity 210 is communicated with the through hole 121, and the through hole 121 is the inlet for the air flow to enter the sound absorption cavity 210. When the centrifugal fan 100 works, the sound waves in the air duct will enter the sound absorption cavity 210 through the through hole 121, and the energy of the sound waves can be consumed through the sound absorption cavity 210, so as to achieve the purpose of reducing noise.

[0075] Refer to Figure 2 and Figure 3As shown, in some embodiments, each sound-absorbing cavity 210 has a certain curvature, and each sound-absorbing cavity 210 has a different length. When a plurality of sound-absorbing cavities 210 are arranged radially along the volute 101, the adjacent layers of sound-absorbing cavities 210 are in contact with each other, and the arrangement is more compact, capable of forming a stacked structure in a fan shape or other shapes; moreover, when each layer of sound-absorbing cavities 210 is arranged circumferentially, they can also match each other, enabling the entire sound-absorbing structure 200 to be circular or fan-shaped, and making it easier to cooperate and connect with the side wall of the volute 101.

[0076] Specifically, one side of the sound-absorbing structure 200 facing the volute 101 is an open structure, and the side away from the volute 101 is covered with a sealing plate 250. The inner cavity of the sound-absorbing structure 200 is divided into a plurality of sound-absorbing cavities 210 by a plurality of partition ribs 220. One side of each sound-absorbing cavity 210 facing the volute 101 is open. Therefore, after connecting the sound-absorbing structure 200 with the volute 101, each sound-absorbing cavity 210 can be directly communicated with the corresponding through hole 121.

[0077] Refer to Figure 3 As shown, in the embodiment, the cross-section of the sound-absorbing cavity 210 is square, and the width of each sound-absorbing cavity 210 is the same. The sound-absorbing structure 200 has five layers of sound-absorbing cavities 210, and each layer of sound-absorbing cavities 210 is arranged circumferentially along the volute 101 in an annular structure, that is, there are five annular structures, and they are arranged radially along the volute 101. The annular structure is coaxially arranged with the wind wheel and the motor. In this way, the sound-absorbing cavities 210 are distributed layer by layer radially outward from the central axial position, achieving the maximum utilization rate of the side space of the volute 101. Compared with the layout method on the annular wall of the volute 101, it will not significantly increase the volume of the volute 101, and the layout design is reasonable.

[0078] It can be understood that if the annular structure deviates from the axis of the wind wheel, the number of sound-absorbing cavities 210 arranged in the manner of the above embodiment is relatively small, and the remaining area on the side wall of the volute 101 is large, reducing the utilization rate of the side space, and the noise reduction effect is also relatively poor.

[0079] Refer to Figure 3 As shown, in the radial direction of the volute 101, the first layer of sound-absorbing cavities 210 is close to the central axis, and the fifth layer of sound-absorbing cavities 210 is located at the outermost layer of the sound-absorbing structure 200. Therefore, the first layer can be understood as the innermost annular structure, and the fifth layer can be understood as the outermost annular structure. In the embodiment, the outer diameter of the outermost annular structure is set slightly larger than the diameter of the wind wheel. It can be understood that the outer diameter of the wind wheel is larger than the diameter of the motor and not greater than the radial dimension of the annular wall. Through the above settings, the radial dimension of the sound-absorbing structure 200 can be effectively increased, so that more sound-absorbing cavities 210 can be arranged, which is beneficial to improving the noise reduction effect.

[0080] In addition, considering that the motor is installed at the central position of the right housing 120, in the embodiment, the inner diameter of the innermost ring structure is set to be slightly larger than the diameter of the motor, so that the sound absorption structure 200 is separated from the motor without affecting the layout of the sound insulation cavity 210. As Figure 2 and Figure 3 shown, the middle position of the sound absorption structure 200 is a hollow structure. The innermost ring structure surrounds and forms a central hole 230, and the axis of the central hole 230 coincides with the axis of the motor, ensuring that the sound absorption structure 200 is coaxially arranged with the motor.

[0081] Combined with Figure 1 it can be understood that a fixing seat 123 for installing the motor is provided at the middle position of the right housing 120. The fixing seat 123 protrudes from the bottom wall of the right housing 120, and reinforcing ribs are distributed on the fixing seat 123. The installation structure of the motor can be strengthened through the fixing seat 123, and the structure is more reliable. The sound absorption structure 200 can avoid the fixing seat 123 through the above-mentioned central hole 230, which not only improves the installation strength of the motor but also does not affect the installation of the sound absorption structure 200 without increasing the overall axial dimension of the centrifugal fan 100.

[0082] Of course, this is only an example. In some embodiments, the outer diameter of the outermost ring structure can be set to be equal to the diameter of the wind wheel, and the inner diameter of the innermost ring structure can also be set to be equal to the diameter of the motor, meeting the requirements of the above installation structure.

[0083] Referring to Figure 4 shown, the outer diameter of the outermost ring structure is D, the inner diameter of the innermost ring structure is d, the width of the sound insulation cavity 210 is w c , the thickness of the isolation rib 220 between adjacent sound insulation cavities 210 is h, the number of layers of the sound insulation cavity 210 is N, and N is a positive integer greater than or equal to 4. That is, the sound absorption structure 200 has at least 4 layers of sound insulation cavities 210. The above parameters satisfy: Nw c +(N + 1)h = 0.5(D - d), where Nw c +(N + 1)h represents the sum of the total widths of N layers of sound insulation cavities 210 and the thicknesses of N + 1 layers of isolation ribs 220, and 0.5(D - d) represents half of the difference between the outer diameter and the inner diameter of the sound absorption structure 200. That is to say, multiple sound insulation cavities 210 are separated from each other by isolation ribs 220 and are arranged in a stacked manner in a circular ring shape.

[0084] Taking a specific example for illustration, when the outer diameter of the outermost ring structure is equal to the diameter of the wind wheel and the inner diameter of the innermost ring structure is equal to the diameter of the motor, D and d in the above formula can be determined. According to the requirements for the width of the sound insulation cavity 210 and the thickness of the isolation rib 220, the specific number of layers can be determined to make the layout more reasonable.

[0085] In some embodiments, the width range of each sound-absorbing cavity 210 is 4 mm to 14 mm, and the thickness range of the isolation rib 220 is 0.6 mm to 2.5 mm. For example, the width of the sound-absorbing cavity 210 can be 4 mm, 8 mm, 10 mm, 14 mm, etc., and the thickness of the isolation rib 220 can be 0.6 mm, 1 mm, 1.5 mm, 2.5 mm, etc. Through the above settings, as many sound-absorbing cavities 210 as possible can be designed in the sound-absorbing structure 200, and the width of the sound-absorbing cavity 210 will not be too narrow to affect the noise reduction effect, ensuring that each sound-absorbing cavity 210 can play an effective sound-absorbing role. The width of the sound-absorbing cavity 210 and the thickness of the isolation rib 220 are specifically selected according to actual requirements and are not limited here.

[0086] It should be noted that the sound-absorbing structure 200 has isolation ribs 220 extending circumferentially and isolation ribs 220 extending radially, so that the sound-absorbing cavities 210 can be separated in the circumferential and radial directions respectively. In this way, the sound-absorbing cavities 210 in the same layer are separated by the isolation ribs 220, and the sound-absorbing cavities 210 between adjacent layers are also separated by the isolation ribs 220.

[0087] In addition, the height range of each sound-absorbing cavity 210 is 2 mm to 20 mm, and can specifically be 2 mm, 10 mm, 20 mm, etc. The sound-absorbing cavity 210 can play an effective sound-absorbing effect within the above size range, avoiding the overall volume of the sound-absorbing structure 200 being affected by too high a height. The specific size is set according to actual requirements.

[0088] Refer to Figure 4 As shown, it can be understood that along the direction away from the wind wheel axis, the number of layers where each annular structure is located is the layer level. The layer level is x and x is greater than or equal to 1 and less than or equal to N. The inner diameter of each annular structure is: r 1 =(x - 1)w c + xh, and the outer diameter is: r 2 = xw c + xh. Taking a specific example for illustration, as Figure 5 shown, the width w c of the sound-absorbing cavity 210 is 10 mm, the thickness h of the isolation rib 220 is 1.2 mm, the inner diameter r 1 of the third-layer annular structure is (3 - 1)*10 + 3*1.2 = 23.6 mm, and the outer diameter r 2 of the third-layer annular structure is 3*10 + 3*1.2 = 33.6 mm. Therefore, when arranging the sound-absorbing cavities 210, the dimensions of each layer can be determined according to the above calculation method.

[0089] Refer to Figure 4As shown, it can be understood that a part of the sound-absorbing cavity 210 in the embodiment is bent along the radial direction of the volute 101 to form a bent portion 211, and another part of the sound-absorbing cavity 210 does not have a bent portion 211; the bent portion 211 can change the extending direction of the sound-absorbing cavity 210, and the bent portion 211 is arranged side by side with the sound-absorbing cavity 210 of the adjacent layer. Combining Figure 5 It can be understood that taking a sound-absorbing cavity 210 in the third layer as an example, one end of the sound-absorbing cavity 210 is bent towards the fourth layer, and its bent portion 211 is arranged side by side with the sound-absorbing cavity 210 of the fourth layer along the circumferential direction. That is to say, the sound-absorbing cavity 210 can extend to different layers through the bent portion 211, making the layout of the sound-absorbing cavity 210 more flexible and increasing the length of the sound-absorbing cavity 210. When the sound-absorbing cavity 210 changes from radial extension to circumferential extension or from circumferential extension to radial extension, it can be understood that one bending occurs, and the number of bending segments is one.

[0090] It should be noted that the width dimension of the sound-absorbing cavity 210 is uniformly set along the length direction, and the width of the non-bent part is approximately the same as that of the bent portion 211. The number of bending segments of the bent portion 211 is not limited to one, and can also be two or more. For example, Figure 5 In the shown example, the bent portion 211 of the above-mentioned sound-absorbing cavity 210 has two bending segments, and the sound-absorbing cavity 210 extends into the annular structures of the fourth layer and the fifth layer in sequence, so as to make more reasonable use of the inner cavity space of the sound-absorbing structure 200 and make the arrangement of the sound-absorbing cavity 210 more compact.

[0091] In some embodiments, all the sound-absorbing cavities 210 are provided with bent portions 211. One end of the sound-absorbing cavity 210 can be bent to form a bent portion 211, or both ends of the sound-absorbing cavity 210 can be bent to form bent portions 211, which are specifically set according to requirements.

[0092] It can be understood that the longer the wavelength of the sound wave, the lower the corresponding frequency. By using sound-absorbing cavities 210 with different lengths, different frequencies of sound waves can be corresponding for noise reduction, and the noise reduction bandwidth of the sound-absorbing structure 200 can be broadened. The specific noise reduction principle of the sound-absorbing cavity 210 is as follows: the sound wave enters the sound-absorbing cavity 210 through the through hole 121, and after reflection, a standing wave is formed. The standing wave has a certain amplitude in space, and the amplitude is the largest at a position far from the through hole 121 in the sound-absorbing cavity 210. Since the air produces a damping effect in a narrow area, the faster the vibration speed, the greater the internal energy consumption. Therefore, the mechanical energy of the sound wave is converted into internal energy through the sound-absorbing cavity 210, consuming the energy of the sound wave, so as to achieve the effect of reducing noise.

[0093] It should be noted that a protruding air outlet passage 260 is formed near the air outlet 130. The air outlet passage 260 extends outward from the position of the volute tongue 140 of the volute 101. That is, the volute 101 is not a standard circle. Therefore, after arranging the sound absorption cavity 210 in the largest possible contour concentric with the impeller, there is still a considerable remaining area on the side close to the air outlet 130 but far from the volute tongue 140. In some embodiments, in this remaining area, an extension layer concentric with the impeller is continuously expanded according to the above layout method. This extension layer is roughly fan-shaped until N reaches the maximum.

[0094] Referring to Figure 1 and Figure 2 As shown, in some embodiments, two sound absorption structures 200 are provided. The two sound absorption structures 200 are stacked together along the axial direction of the volute 101. The sound absorption structure 200 connected to the volute 101 is the first sound absorption structure 201, and the other is the second sound absorption structure 202. The second sound absorption structure 202 is arranged on the side of the first sound absorption structure 201 away from the volute 101. The first sound absorption structure 201 and the second sound absorption structure 202 are arranged at intervals, and a plurality of sound absorption cavities 210 are respectively provided. The layout structures of the sound absorption cavities 210 in the two sound absorption structures 200 can be arranged according to the above examples.

[0095] Referring to Figure 3 and Figure 6 As shown, specifically, the sound absorption cavities 210 of the first sound absorption structure 201 are arranged according to the embodiment shown in Figure 3 The sound absorption cavities 210 of the second sound absorption structure 202 are arranged according to the embodiment shown in Figure 6 The number of through holes 121 provided on the volute 101 is the same as the number of sound absorption cavities 210 in the two sound absorption structures 200, so that all the sound absorption cavities 210 are in one-to-one correspondence and communication with the through holes 121. In this way, the number of sound absorption cavities 210 can be effectively increased. Compared with a single sound absorption structure 200, the noise reduction bandwidth of the sound absorption structure 200 is more effectively broadened. The effective bandwidth near 1000 Hz reaches 800 Hz. Therefore, the noise reduction performance for the noise with the main frequency of 1000 Hz is relatively ideal, and the noise reduction effect is better.

[0096] It can be understood that the noise reduction principle of each sound absorption cavity 210 can refer to the description of the above embodiments. That is to say, the sound absorption cavities 210 in the first sound absorption structure 201 and the second sound absorption structure 202 both play a similar noise reduction effect. Taking a specific sound absorption cavity 210 as an example for illustration, Figure 5 shows the sound wave propagation paths of two sound absorption cavities 210 in the first sound absorption structure 201, Figure 8 shows the sound wave propagation paths of two sound absorption cavities 210 in the second sound absorption structure 202. The direction indicated by the arrow is the direction of the sound wave.

[0097] Referring toFigure 4 and Figure 7 As shown in Figure 7 , a partition 240 is provided between the first sound absorption structure 201 and the second sound absorption structure 202. The partition 240 is provided with a plurality of openings 241. The openings 241 penetrate through the partition 240 and are in one-to-one correspondence and communication with the sound absorption cavities 210 in the second sound absorption structure 202. In addition, a channel 260 is provided in the first sound absorption structure 201. The channel 260 is used to connect the openings 241 and the through holes 121, so that the sound absorption cavities 210 of the second sound absorption structure 202 are connected to the through holes 121, and sound waves can sequentially pass through the through holes 121, the channel 260, and the openings 241 and enter the sound absorption cavities 210 of the second sound absorption structure 202.

[0098] It can be understood that the channel 260 is formed in the first sound absorption structure 201 and is arranged at intervals with each sound absorption cavity 210. Specifically, the channel 260 is separated from the sound absorption cavity 210 by a partition rib 220, and each channel 260 is connected to the corresponding through hole 121. In addition, the position of the opening 241 is at the front end or the tail end of the sound absorption cavity 210 of the second sound absorption structure 202. At the same time, a sealing plate 250 is provided on the side of the second sound absorption structure 202 away from the first sound absorption structure 201 to form a closed structure.

[0099] Combined with Figure 9 it can be understood that Figure 9 FIG. Figure 9 shows a partial cross-sectional schematic view of two sound absorption structures 200. Among them, the lower side is the first sound absorption structure 201, and the upper side is the second sound absorption structure 202. The sound absorption cavity 210 of the second sound absorption structure 202 is connected to the channel 260 through the opening 241, and the positions of the opening 241 and the channel 260 correspond one by one. In addition, the heights of the sound absorption cavities 210 on the upper side and the lower side are substantially the same, and the height h c is in the range of 2 mm to 20 mm. In this way, when two sound absorption structures 200 are stacked together, the volume of the centrifugal fan 100 will not be significantly increased, and the noise reduction effect is also guaranteed. In addition, in the embodiment, the thickness h w of the partition 240 ranges from 1 mm to 2.5 mm. By setting the above thickness, the partition 240 can satisfy the separation of the first sound absorption structure 201 and the second sound absorption structure 202, and will not significantly increase the overall height dimension.

[0100] Referring to Figure 1 and Figure 2As shown, it should be noted that the first sound-absorbing structure 201 and the second sound-absorbing structure 202 are integrally formed with the partition plate 240. The partition ribs 220 in the two sound-absorbing structures 200 are both connected to the partition plate 240, and the whole has sufficient structural strength. Only by fixedly connecting the sealing plate 250 to the volute 101 can the sound-absorbing cavities 210 of the two sound-absorbing structures 200 form independent spaces, and the installation is more convenient. In some embodiments, the sound-absorbing structure 200 can also be integrally formed with the volute 101 or the sealing plate 250 to further simplify the structure.

[0101] Of course, this is only an example here. The number of the sound-absorbing structures 200 is not limited to two, and can also be three or more. For example, three sound-absorbing structures 200 can be stacked on the outer wall of the volute 101 in sequence. Channels 260 are respectively arranged in the two sound-absorbing structures 200 close to the volute 101. In this way, the sound-absorbing cavities 210 of the sound-absorbing structure 200 far from the volute 101 are respectively communicated to the through holes 121 through the channels 260. In this way, more sound-absorbing structures 200 can be expanded, and specific selection can be made according to practical requirements.

[0102] It can be understood that in the embodiments of the present invention, different sound-absorbing cavities 210 are separated by partition ribs 220. In this way, at least 10 sound-absorbing cavities 210 with a length greater than or equal to 25 mm are formed in each sound-absorbing structure 200. The length of the sound-absorbing cavity 210 is understood as the length of the midline in the sound-absorbing cavity 210. For example, 12 sound-absorbing cavities 210 with a length greater than or equal to 25 mm are arranged in the first sound-absorbing structure 201. Each sound-absorbing cavity 210 has a bending part 211. The specific length can be 25 mm, 30 mm, 32 mm, etc. Each sound-absorbing cavity 210 can have different lengths. In this way, different sound-absorbing cavities 210 have different acoustic impedance characteristics, broadening the noise reduction bandwidth of the sound-absorbing structure 200 and achieving better noise reduction effect.

[0103] Refer to Figure 4 As shown, it should be noted that the length of each channel 260 is less than or equal to 15 mm, and the width is the same as that of the sound-absorbing cavity 210. Since the sound-absorbing cavity 210 in the second sound-absorbing structure 202 is communicated with the corresponding channel 260, when calculating its acoustic impedance characteristics, the sum of the length of the sound-absorbing cavity 210 and the length of the channel 260 is taken as the standard. In the embodiment, at least 8 channels 260 are provided in the channel 260 of the first sound-absorbing structure 201, and the number of the channels 260 is the same as the number of the sound-absorbing cavities 210 in the second sound-absorbing structure 202.

[0104] The inventors found that in the related art, it was also proposed to use an ultra-thin metamaterial muffler to reduce the noise of the centrifugal fan 100. However, there is a situation where the through holes 121 inside the volute 101 cannot avoid the high-speed airflow area 150. Secondary aerodynamic noise will be generated at high wind speeds, resulting in a significant decrease in the noise reduction effect at high air volumes compared to low air volumes. Based on this, for the ultra-thin metamaterial muffler with a bendable cavity, the additional noise reduction benefit of continuing to increase the thickness is not significant, and the use effect is not good.

[0105] In response to this, in the embodiments of the present invention, the distribution position of the through holes 121 on the volute 101 is optimized to reduce the influence of secondary aerodynamic noise. In the embodiments, it is necessary to refer to the airflow velocity field on the plane near the right side wall 122 inside the volute 101, that is, within 1 mm of the bottom wall on the inner side of the right housing 120. When arranging the sound-absorbing cavity 210, it should be made as far as possible that the front or rear end position of the vertical projection of the sound-absorbing cavity 210 on this plane is far from the high-speed airflow area 150 near the bottom wall.

[0106] Referring to Figure 10 and Figure 11 as shown, Figure 10 shows the outer structure of the right housing 120, Figure 11 shows the inner structure of the right housing 120. Specifically, the volute 101 has a high-speed airflow area 150, and the high-speed airflow area 150 includes a fan-shaped area 151 and an annular area 152. Among them, with the center axis of the wind wheel as the center P, a straight line tangent to the volute tongue 140 of the volute 101 is drawn from the center P. The area formed by rotating the line segment PE from the center P to the tangent point E by 60° along the rotation direction of the wind wheel is the fan-shaped area 151; the area formed with the center axis of the wind wheel as the center P and with the first length L1 as the inner diameter and the second length L2 as the outer diameter is the annular area 152. Among them, the ratio of the first length L1 to the diameter of the wind wheel is 0.9, and the ratio of the second length L2 to the diameter of the wind wheel is 1.1. That is, the inner diameter of the annular area 152 is 90% of the diameter of the wind wheel, and the outer diameter of the annular area 152 is 110% of the diameter of the wind wheel.

[0107] On the projection plane perpendicular to the axial direction of the wind wheel, the number of through holes 121 located within the projection of the high-speed airflow area 150 is less than or equal to 15% of the total number of through holes 121. Figure 11 In the shown example, a total of 39 through holes 121 are provided on the volute 101, and 4 of them are located in the high-speed airflow area 150. That is, the number of through holes 121 located in the high-speed airflow area 150 accounts for 10% of the total number, that is, the proportion does not exceed 15%. In this way, the appearance of through holes 121 in the high-speed airflow area 150 of the volute 101 is reduced, thereby reducing the generation of secondary aerodynamic noise and having a better noise reduction effect.

[0108] Referring to Figure 10 andFigure 11 As shown, in the embodiment, the through hole 121 is generally rectangular, and the depth h of the through hole 121 ORF is the same as the thickness of the right side wall 122 of the volute 101. The width w of the through hole 121 ORF is greater than or equal to 1 / 4 of the width of the corresponding sound absorption cavity 210 and less than or equal to the width of the sound absorption cavity 210, so that the through hole 121 will not be too small to affect the noise reduction effect and will not exceed the width of the sound absorption cavity 210. Specifically, the length of the through hole 121 is 1 mm to 5 mm, and can be 1 mm, 2 mm or 5 mm, etc.

[0109] In some embodiments, the through hole 121 is a fan-shaped hole, and the inner arc length of the fan-shaped hole is 1 mm to 5 mm, and can be 1 mm, 2 mm or 5 mm, etc. In addition, the above-mentioned rectangular hole or fan-shaped hole can be a straight hole, or a straight inclined hole with a maximum inclination angle of 45°, or a spiral inclined hole with a maximum spiral inclination angle of 45°. By setting the above-mentioned through hole 121, it is beneficial to reduce the high-speed airflow from entering the through hole 121, further reduce the generation of secondary aerodynamic noise, and have less influence on the air volume of the centrifugal fan 100.

[0110] Next, by calculating the acoustic impedance of the entire sound absorption structure 200, its noise reduction effect can be determined. Specifically, according to the sound absorption rate α = 1 - ((Z - Z 0 ) / (Z + Z 0 )) 2 , where Z 0 is the acoustic impedance of air, which is a constant, and Z is the acoustic impedance of the sound absorption structure 200; thus, it can be seen that by obtaining the acoustic impedance Z of the sound absorption structure 200, the sound absorption rate α can be obtained, and thus its noise reduction effect can be evaluated.

[0111] Considering that in the embodiment of the present invention, the sound absorption cavity 210 may have a bending portion 211, and each sound absorption cavity 210 has a different length, so different sound absorption cavities 210 have different acoustic impedances; in addition, since the through hole 121 has a certain depth, it has a certain acoustic impedance, and by increasing the acoustic impedance of the through hole 121, the accuracy can be improved.

[0112] Referring to Figure 8 as shown, specifically, the part of the sound absorption cavity 210 directly connected to the through hole 121 is the first-stage cavity 212, and the first-stage cavity 212 does not bend; according to its level, multiply (x i - 0.5)w c + x i h by the fan angle occupied by this first-stage cavity 212 and denote it as l ci . After bending occurs, the part at a different level from the previous cavity is the second-stage cavity 213, and so on. According to the number of bends, it can be deduced to the Mth-stage cavity.

[0113] The acoustic impedance Z of the sound absorption structure 200 satisfies: where Z OC represents the acoustic impedance of the through-hole 121 and a single sound absorption cavity 210, and n represents the ordinal number of the unit formed by the combination of the through-hole 121 and the sound absorption cavity 210.

[0114] The acoustic impedance Z of the unit formed by the combination of the above-mentioned through-hole 121 and the sound absorption cavity 210 OC satisfies:

[0115]

[0116] where, Z ORF is the acoustic impedance of the through-hole 121, φ is the area correction coefficient, is the acoustic impedance of the first-stage cavity 212 communicated with the through-hole 121. The acoustic impedance Z of the through-hole 121 can be calculated according to the following formula ORF and the acoustic impedance of the sound absorption cavity 210

[0117]

[0118] where, h ORF is the depth of the through-hole 121, w ORF is the width of the through-hole 121, j is the imaginary part of the complex number, i is the i-th cavity, M is the number of bent segments of the sound absorption cavity 210, i = 1 represents the first-stage cavity 212, and i = M represents the cavity of the sound absorption cavity 210 far from the through-hole 121; l i is the equivalent length (diagonal length) of the i-th cavity, μ is the air dynamic viscosity, is the local area correction coefficient, ΔNL is the non-linear effect correction coefficient, ΔAM is the acoustic mass correction coefficient, is the local equivalent wavelength, is the local air equivalent characteristic impedance;

[0119] Then the corresponding parameters above can be obtained according to the following formula;

[0120]

[0121]

[0122] where, is the equivalent air density, is the equivalent sound speed, ρ 0 is the air density, μ′ is the air thermal viscosity, ω is the working angular frequency, γ is the specific heat ratio, P 0 is the atmospheric pressure.

[0123] Combined Figure 12 It can be understood that Figure 12 The sound absorption rate - frequency simulation results of the sound absorption structure 200 of the centrifugal fan 100 in the embodiment are shown. By adopting the above - mentioned sound absorption structure 200, the centrifugal fan 100 plays an effective noise reduction role in the frequency band range of 800 Hz to 1600 Hz. It can reach the sound absorption peak at specific frequencies. For example, there are sound absorption peaks between 1100 Hz and 1200 Hz and between 1300 Hz and 1400 Hz. Through the formation of acoustic coupling by multiple sound - absorbing cavities 210 in space and frequency domain, a broadband sound absorption effect with a bandwidth exceeding 500 Hz is achieved.

[0124] In addition, the sound absorption structure 200 of the embodiment has the advantage of small volume, only slightly increasing the volume of the centrifugal fan 100. The centrifugal fan 100 equipped with the above - mentioned sound absorption structure 200 has a better air volume - noise curve than the original machine (without the sound absorption structure 200). Moreover, two sound absorption structures 200 can be arranged, greatly increasing the number of sound - absorbing cavities 210, with a more flexible layout and better noise reduction effect.

[0125] Referring to Figure 1 and Figure 2 As shown, an embodiment of the present invention also proposes a fresh - air module 1000, which includes the centrifugal fan 100 of the above - mentioned embodiment. The centrifugal fan 100 is provided with a wind - guiding part 300. The wind - guiding part 300 is connected to the outside of the volute 101 and covers the air inlet. An air inlet channel 310260 is arranged in the wind - guiding part 300, and the air inlet channel 310260 is communicated with the air inlet. The centrifugal fan 100 is communicated with the outside through the wind - guiding part 300, and outdoor air can enter the centrifugal fan 100 through the air inlet channel 310260, and the centrifugal fan 100 supplies air to the room, enabling the indoor environment to obtain fresh air. Figure 2 The direction indicated by the arrow in is the direction of air flow in the fresh - air module 1000. The air sequentially passes through the air inlet channel 310260, the air inlet, the air duct and the air outlet 130 and enters the room.

[0126] The fresh - air module 1000 can be used alone, or the fresh - air module 1000 can be used in combination with an air - conditioner indoor unit. By adding the sound absorption structure 200 on the volute 101, the sound absorption structure 200 can play a noise reduction role, effectively reducing the noise generated by the fresh - air module 1000; and the sound absorption structure 200 does not significantly increase the volume of the centrifugal fan 100, has higher installation compatibility, and does not require filling resistive sound - absorbing materials, with higher safety and reliability, which is beneficial to improving the operation stability of the fresh - air module 1000.

[0127] An embodiment of the present invention further provides an indoor air conditioner, which includes the fresh air module 1000 of the above embodiment. The indoor air conditioner can be a wall-mounted unit, a cabinet-type unit, etc. The fresh air module 1000 adds a sound absorption structure 200 to the volute 101. The sound absorption structure 200 does not significantly increase the volume of the centrifugal fan 100, and there is no need to fill resistive sound absorption materials, so the safety and reliability are higher, which is beneficial to improving the operation stability of the indoor air conditioner.

[0128] An embodiment of the present invention further provides an air conditioner, which includes the indoor air conditioner of the above embodiment, and the indoor air conditioner is installed with the fresh air module 1000 of the above embodiment.

[0129] Since the air conditioner adopts all the technical solutions of all the above embodiments, it has at least all the beneficial effects brought by the technical solutions of the above embodiments, which will not be elaborated here one by one.

[0130] The above has described the embodiments of the present invention in detail with reference to the drawings. However, the present invention is not limited to the above embodiments. Within the scope of knowledge possessed by those of ordinary skill in the art, various changes can be made without departing from the gist of the present invention.

Claims

1. A centrifugal fan, It is characterized in that include: A volute, wherein an air duct is provided therein, the volute is provided with an air inlet, a side of the volute away from the air inlet is provided with a plurality of through holes, the air inlet and the plurality of through holes are both in communication with the air duct; A sound absorbing structure is connected to the volute and is located on the side wall where the through hole is located. The sound absorbing structure includes a plurality of silencer cavities arranged at intervals. The plurality of silencer cavities are arranged in multiple layers along the radial direction of the volute. Each layer has at least one silencer cavity. The silencer cavities are connected to the through holes in a one-to-one correspondence.

2. The centrifugal fan according to claim 1, It is characterized in that The centrifugal fan also includes: A motor is arranged on a side of the volute opposite to the air inlet; A wind wheel, located in the wind duct and connected to the motor; The sound absorbing structure is located on the side of the volute away from the motor, each layer has a plurality of silencer cavities arranged in an annular structure along the circumference of the volute, and the annular structure is coaxially arranged with the wind wheel.

3. The centrifugal fan according to claim 2, It is characterized in that Along the radial direction of the volute, the outer diameter of the outermost annular structure is greater than or equal to the diameter of the wind wheel, and the inner diameter of the innermost annular structure is greater than or equal to the diameter of the motor.

4. The centrifugal fan according to claim 3, It is characterized in that The width of the sound absorption cavity is w c , there are isolation ribs between adjacent sound absorption cavities, the thickness of the isolation ribs is h, the outer diameter of the outermost ring structure is D, the inner diameter of the innermost ring structure is d, the number of layers of the sound absorption cavity is N, and N is an integer greater than or equal to 4, satisfying: Nw c +(N + 1)h = 0.5(D - d).

5. The centrifugal fan according to claim 4, It is characterized in that In the direction away from the axis of the wind wheel, the layer number of each layer of the annular structure is the hierarchy level, the hierarchy level is x and x is greater than or equal to 1 and less than or equal to N, and the inner diameter of each layer of the annular structure satisfies: r 1 =(x - 1)w c + xh, and the outer diameter satisfies: r 2 = xw c + xh.

6. The centrifugal fan according to claim 4, It is characterized in that The width of the muffler cavity ranges from 4 mm to 14 mm, and the thickness of the isolation rib ranges from 0.6 mm to 2.5 mm.

7. The centrifugal fan according to claim 1, It is characterized in that At least a portion of the muffler cavity is bent along the radial direction of the volute to form a bent portion, and the bent portion is arranged side by side with the muffler cavity of an adjacent layer.

8. The centrifugal fan according to claim 1, It is characterized in that At least two sound absorbing structures are provided, and the at least two sound absorbing structures are arranged in sequence along a direction away from the air duct, and the silencer cavities of all the sound absorbing structures are connected to the through holes in a one-to-one correspondence.

9. The centrifugal fan according to claim 8, It is characterized in that At least two of the sound absorbing structures include a first sound absorbing structure and a second sound absorbing structure, the second sound absorbing structure is arranged on a side of the first sound absorbing structure away from the volute, a partition is arranged between the first sound absorbing structure and the second sound absorbing structure, the partition is provided with a plurality of openings, the openings are connected one-to-one with the silencer chamber in the second sound absorbing structure, and the first sound absorbing structure is also provided with a channel for connecting the openings with the through holes.

10. The centrifugal fan according to claim 9, It is characterized in that At least part of the silencer cavity is bent along the radial direction of the volute to form a bending portion, and the bending portion is arranged side by side with the silencer cavity of the adjacent layer. Each of the sound absorbing structures is provided with at least 10 silencer cavities with a length greater than or equal to 25 mm.

11. The centrifugal fan according to claim 9, It is characterized in that The height of the sound-absorbing cavity in the first sound-absorbing structure is the same as that of the sound-absorbing cavity in the second sound-absorbing structure, and the height is 2 mm to 20 mm, and the thickness range of the partition is 1 mm to 2.5 mm.

12. The centrifugal fan according to claim 2, wherein, a high-speed air flow area is provided in the volute, and the high-speed air flow area includes: a fan-shaped area, which is centered on the central axis of the impeller, and a straight line drawn from the center intersects the volute tongue of the volute, and a region formed by rotating the line segment between the tangent point and the center by 60° along the rotation direction of the impeller; an annular area, which is centered on the central axis of the impeller and formed with an inner diameter of a first length and an outer diameter of a second length, and the ratio of the first length to the diameter of the impeller is 0.9, and the ratio of the second length to the diameter of the impeller is 1.1; On the projection plane perpendicular to the axial direction of the impeller, the number of the through holes located within the projection of the high-speed air flow area is less than or equal to 15% of the total number of the through holes.

13. The centrifugal fan according to claim 1 or 12, wherein, the maximum width of the through hole is greater than or equal to 1 / 4 of the width of the sound-absorbing cavity and less than or equal to the width of the sound-absorbing cavity.

14. The centrifugal fan according to claim 13, wherein, the through hole is a square hole with a length of 1 mm to 5 mm, or the through hole is a fan-shaped hole with an arc length of 1 mm to 5 mm.

15. A fresh air module, wherein, comprising: the centrifugal fan according to any one of claims 1 to 14; a wind guiding part, which is connected to the outside of the volute and covers the air inlet, and the wind guiding part is provided with an air inlet channel communicated with the air inlet.

16. An air conditioner indoor unit, wherein, comprises the fresh air module according to claim 15.

17. An air conditioner, wherein, comprises the air conditioner indoor unit according to claim 16.

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