Impeller, cross-flow fan, and air conditioner

Abstract

An impeller, a cross-flow fan, and an air conditioner. The impeller comprises a disc (3); the disc (3) is provided with a first side (31) and a second side (32) opposite to each other; blades (4) are arranged on the first side (31), and welding grooves (2) used for being welded to the blades (4) on another impeller are formed on the second side (32); two or more welding grooves (2) are formed and sequentially arranged at intervals in the circumferential direction of the disc (3); silencing grooves (1) are also formed on the second side (32), and each silencing groove (1) is located between every two adjacent welding grooves (2). The impeller can change the frequency of collision between an airflow and a wall surface of the disc, and also can define a silencing cavity structure for silencing the airflow flowing therethrough, thus reducing the generation and propagation of noise.

Description

Middle section fan blade, cross flow fan blade and air conditioner

[0001] This disclosure claims priority to a Chinese patent application filed with the Patent Office of China on August 18, 2023, with application number 202311052482.0 and invention name “A mid-section fan blade, a cross-flow fan blade and an air conditioner”, the entire contents of which are incorporated by reference into this disclosure. Technical Field

[0002] The present disclosure relates to the technical field of air conditioning, and in particular to a mid-section fan blade, a cross-flow fan blade and an air conditioner. Background Art

[0003] As shown in Figure 1, a crossflow blade includes a shaft cover 1, an end cover 3, and multiple mid-section blades 2. As shown in Figure 2, a mid-section blade 2 includes a disk 21 and blades 22 disposed on one side of the disk 21. A welding groove 211 is provided on the side of the disk 21 facing away from the blades 22. The disk 21 is welded to the blades 22 of another mid-section blade 2 through the welding groove 211. Blades 22 are welded by manually rotating the mid-section blade 2 to locate the welding groove 211.

[0004] During the rotation of the crossflow blades, the airflow periodically impacts the surrounding solid surfaces, resulting in gas pressure pulsations and aerodynamic rotational noise. These solid surfaces include the surfaces of the blades 22 and the disk 21 that secures them. Existing crossflow blades have been designed to mitigate aerodynamic noise by modifying the blade surface structure. Given that the existing blade structure mold is fixed, further improving the aerodynamic noise of crossflow blades has become an urgent challenge in the field.

[0005] Summary of the Invention

[0006] In view of this, the present disclosure provides a mid-section fan blade, a cross-flow fan blade and an air conditioner, the main technical problem to be solved is: how to further reduce the aerodynamic noise when the cross-flow fan blade rotates.

[0007] To achieve the above objectives, the present disclosure mainly provides the following technical solutions:

[0008] In a first aspect, embodiments of the present disclosure provide a mid-section wind blade, comprising a circular disc having a first side and a second side opposite to each other, the first side being provided with a blade, the second side being provided with a welding groove for welding to a blade on another mid-section wind blade, the number of the welding grooves being two or more and being sequentially spaced apart along the circumference of the circular disc;

[0009] Wherein, the second side is further provided with a silencer groove, and the silencer groove is located between two adjacent welding grooves.

[0010] In some embodiments, the number of the muffler grooves is two or more, and they are arranged in sequence and spaced apart along the circumference of the disc;

[0011] In a cross section perpendicular to the axial direction of the middle-section fan blade, the cross-sectional profile areas of the silencer grooves are different.

[0012] In some embodiments, the angle between the center of each of two adjacent welding grooves and the center of the middle section blade is β, wherein the muffler groove is provided only between two welding grooves where β is greater than or equal to 9°;

[0013] Alternatively, the aforementioned silencer groove is provided between each two adjacent welding grooves.

[0014] In some embodiments, the three welding grooves sequentially arranged along the circumference of the disk are respectively a first welding groove, a second welding groove, and a third welding groove;

[0015] The muffler groove includes a first muffler groove located between the first welding groove and the second welding groove and a second muffler groove located between the second welding groove and the third welding groove;

[0016] In a cross section perpendicular to the axial direction of the middle section fan blade, the angle between the center of the first silencer groove and the second silencer groove and the center of the middle section fan blade is θ, the angle between the center of the first welding groove and the second welding groove and the center of the middle section fan blade is β1, and the angle between the center of the second welding groove and the third welding groove and the center of the middle section fan blade is β2; wherein, θ = (β1+β2) / 2.

[0017] In some embodiments, the depth h of the muffler groove satisfies: 0.5 mm ≤ h ≤ 2 mm;

[0018] And / or, the distance d between the silencer groove and the adjacent welding groove satisfies: 1 mm ≤ d ≤ 1.2 mm.

[0019] In some embodiments, in a cross section perpendicular to the axial direction of the middle-node fan blade, the cross-sectional profile of the muffler groove has a first curve and a second curve opposite to each other, the first curve and the second curve being connected by a first arc on a side close to the center of the middle-node fan blade, and the first curve and the second curve being connected by a second arc on a side away from the center of the middle-node fan blade;

[0020] The distance between the center of the first arc and the center of the middle section fan blade is equal to the inner diameter D1 of the blade, the distance between the center of the second arc and the center of the middle section fan blade is D2, and the outer diameter of the blade is D3, wherein D2≤0.95D3.

[0021] In some embodiments, the first curve is a convex curve, and the convex curve and the convex surface of the blade have the same convex direction;

[0022] And / or, the second curve is a concave curve, and the concave direction of the concave curve and the concave surface of the blade are consistent.

[0023] In some embodiments, the distance L between the first curve and the second curve gradually increases in a direction approaching the center of the middle-node blade, and the distance L between the first curve and the second curve satisfies: 0.6 mm ≤ L ≤ 2.85 mm.

[0024] In some embodiments, in a cross section perpendicular to the axial direction of the mid-section wind blade, the center line of the cross-sectional profile of the blade includes two or more arcs connected in sequence, and the radius and central angle of each arc are different, wherein the center of the maximum thickness of the blade is located on the arc on the side of the center line away from the center of the mid-section wind blade; and along the direction approaching the center of the mid-section wind blade, the thickness of the blade gradually increases to a maximum and then gradually decreases.

[0025] In a second aspect, an embodiment of the present disclosure provides a cross-flow fan blade, which may include any of the above-mentioned mid-section fan blades.

[0026] In a third aspect, an embodiment of the present disclosure provides an air conditioner, which may include any of the above-mentioned cross-flow blades.

[0027] By means of the above technical solution, the section blade, crossflow blade and air conditioner disclosed in the present invention have at least the following beneficial effects:

[0028] 1. In the technical solution provided by the present invention, a silencer groove is provided between two adjacent welding grooves so that the airflow can flow through the silencer groove when the cross-flow fan blade rotates. The silencer groove can change the frequency of the airflow colliding with the wall surface of the disc, thereby reducing the aerodynamic noise when the cross-flow fan blade rotates. When the cross-flow fan blade is applied to an air conditioner, the noise quality of the air conditioner can be improved. In addition, the center line of the silencer groove is parallel to the axis of the middle section fan blade. When the cross-flow fan blade rotates, the airflow flows radially into the interior of the cross-flow fan blade. The center line of the silencer groove intersects perpendicularly with the direction of the airflow, so that the silencer groove can form a silencer cavity structure to silence the airflow passing through, thereby further reducing the propagation of noise. In addition, by providing a silencer groove on the disc, the weight of the disc is reduced, thereby reducing the power consumption of the cross-flow fan blade. When the cross-flow fan blade is applied to an air conditioner, the power of the air conditioner can be reduced.

[0029] 2. By designing the shape of the blades, the airflow angle can be changed and the separation vortex on the blade surface can be reduced, thereby reducing power loss and increasing air volume, reducing the vortex noise on the blade surface, and further improving the noise effect.

[0030] The above description is only an overview of the technical solution of the present disclosure. In order to more clearly understand the technical means of the present disclosure and to implement them according to the contents of the specification, the following is a detailed description of the preferred embodiments of the present disclosure with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] In order to more clearly illustrate the technical solutions in the embodiments of the present disclosure or related technologies, the following briefly introduces the drawings required for use in the embodiments or related technical descriptions. Obviously, the drawings described below are only some embodiments of the present disclosure. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without paying any creative work.

[0032] FIG1 is a schematic structural diagram of a cross-flow fan blade in the related art;

[0033] FIG2 is a schematic structural diagram of a middle section fan blade in the related art;

[0034] FIG3 is a schematic structural diagram of a mid-section wind blade provided by an embodiment of the present disclosure;

[0035] Figure 4 is a top view of the middle section of the fan blade;

[0036] FIG5 is an enlarged schematic diagram of point A in FIG4 ;

[0037] FIG6 is a cross-sectional view taken along line CC in FIG4 ;

[0038] FIG7 is an enlarged schematic diagram of point B in FIG6;

[0039] Figure 8 is a schematic diagram of the structure of the blade;

[0040] FIG9 shows a comparison diagram of the noise effects of a conventional crossflow fan blade and the crossflow fan blade disclosed herein.

[0041] Figure markings: 1. Silencing groove; 2. Welding groove; 3. Disc; 4. Blade; 11. First silencing groove; 12. Second silencing groove; 21. First welding groove; 22. Second welding groove; 23. Third welding groove; 31. First side; 32. Second side; 41. First a-arc; 42. Second a-arc; 43. Convex surface of blade; 44. Concave surface of blade; 101. First curve; 102. Second curve; 103. First arc; 104. Second arc. DETAILED DESCRIPTION

[0042] The following will clearly and completely describe the technical solutions in the embodiments of the present disclosure in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present disclosure, not all of the embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present disclosure without making any creative efforts shall fall within the scope of protection of the present disclosure.

[0043] It should be noted that if the embodiments of the present disclosure involve directional indications (such as up, down, left, right, front, back, etc.), the directional indications are only used to explain the relative position relationship, movement status, etc. between the various components under a certain specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indications will also change accordingly.

[0044] In addition, if there are descriptions involving "first", "second", etc. in the embodiments of the present disclosure, the descriptions of "first", "second", etc. are only for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of such features. In addition, the technical solutions between the various embodiments can be combined with each other, but they must be based on the fact that they can be implemented by ordinary technicians in this field. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such a combination of technical solutions does not exist and is not within the scope of protection required by the present disclosure.

[0045] As shown in Figures 3 and 6, an embodiment of the present disclosure provides a mid-section wind blade, which includes a disk 3 having a first side 31 and a second side 32 opposite to each other. The first side 31 is provided with a blade 4, which can be integrally formed on the disk 3. The second side 32 is provided with a welding groove 2 for welding to the blade 4 on another mid-section wind blade. The number of welding grooves 2 is two or more, and they are arranged in sequence along the circumference of the disk 3. In some embodiments, the sizes of the welding grooves 2 are the same, and the number of welding grooves 2 is the same as the number of blades 4.

[0046] The second side 32 is further provided with a silencer groove 1 , which is located between two adjacent welding grooves 2 .

[0047] In the above example, by providing a silencer groove 1 between two adjacent welding grooves 2, the airflow can flow through the silencer groove 1 when the cross-flow blade rotates. The silencer groove 1 can change the frequency of the airflow colliding with the wall surface of the disc 3, thereby reducing the aerodynamic noise when the cross-flow blade rotates. When the cross-flow blade is applied to an air conditioner, the noise quality of the air conditioner can be improved. In addition, the center line of the silencer groove 1 is parallel to the axis of the middle section blade. When the cross-flow blade rotates, the airflow flows radially into the interior of the cross-flow blade. The center line of the silencer groove 1 intersects perpendicularly with the direction of the airflow, so that the silencer groove 1 can form a silencer cavity structure to silence the airflow passing through, thereby further reducing the propagation of noise. In addition, by providing the silencer groove 1 on the disc 3, the weight of the disc 3 is reduced, thereby reducing the power consumption of the cross-flow blade. When the cross-flow blade is applied to an air conditioner, the power of the air conditioner can be reduced.

[0048] It should be noted here that: in the case where the existing blade structure mold is already fixed, in order to maintain the structure of the existing blade structure mold and reduce the cost of mold modification, the above-mentioned silencer groove 1 is preferably a cutout provided on the disc 3. Specifically, the existing blade structure mold can be used to integrally injection mold the middle section fan blade, and then the injection-molded middle section fan blade can be sent to a milling machine or other equipment for cutting processing to cut the above-mentioned silencer groove 1 on the second side 32 of the disc 3. Therefore, the above-mentioned silencer groove 1 is sometimes also referred to as a silencer cutout or cutout.

[0049] As shown in Figure 3, the number of the aforementioned silencer grooves 1 can be more than two, and they are arranged in sequence along the circumference of the disk 3. In the cross section perpendicular to the axial direction of the middle section blade, the cross-sectional profile area of ​​each silencer groove 1 is different.

[0050] In the above example, providing a greater number of silencer grooves 1 can further reduce the aerodynamic noise of the rotating crossflow blade. Furthermore, by varying the cross-sectional area of ​​each silencer groove 1, the frequency of airflow impacting the wall surface of disk 3 during rotation of the crossflow blade can be further varied, thereby further reducing the aerodynamic noise of the rotating crossflow blade.

[0051] In a specific application example, as shown in Figure 4, the centers of two adjacent weld grooves 2 are connected to the center of the middle section blade, and the angle between the two connecting lines is β. The aforementioned silencer groove 1 is only provided between two weld grooves 2 where β is greater than or equal to 9°. In other words, no silencer groove 1 is provided between two weld grooves 2 where β is less than 9°.

[0052] In the above example, when the angle β between the two welding grooves 2 is ≥9°, the area between the two welding grooves 2 is relatively spacious, thereby making it more convenient to process the silencer groove 1 .

[0053] It should be noted here that the center of the above-mentioned welding groove 2 may refer to the center of the arc of the welding groove 2 on the side close to the center of the middle-section wind blade.

[0054] In another example, while ensuring the overall strength of the middle-section fan blade and the distance d between the silencer groove 1 and the welding groove 2, the aforementioned silencer groove 1 can be set between each two adjacent welding grooves 2, so that a larger number of silencer grooves 1 can further reduce the aerodynamic noise when the cross-flow fan blade rotates.

[0055] It should be noted here that: for the convenience of processing, only one silencer groove 1 is provided between the two adjacent welding grooves 2 .

[0056] In a specific application example, as shown in FIG4 , the three welding grooves 2 arranged sequentially along the circumference of the disk 3 are respectively a first welding groove 21, a second welding groove 22, and a third welding groove 23. The muffler groove 1 includes a first muffler groove 11 located between the first and second welding grooves 2, and a second muffler groove 12 located between the second and third welding grooves 2.

[0057] In a cross section perpendicular to the axial direction of the middle section fan blade, the centers of the first silencer groove 11 and the second silencer groove 12 are connected to the center of the middle section fan blade, and the angle between the two lines is θ. The centers of the first welding groove 21 and the second welding groove 22 are connected to the center of the middle section fan blade, and the angle between the two lines is β1. The centers of the second welding groove 22 and the third welding groove 23 are connected to the center of the middle section fan blade, and the angle between the two lines is β2. Wherein, θ = (β1 + β2) / 2.

[0058] In the above example, the angle arrangement allows the silencer groove 1 to be located centrally between two adjacent weld grooves 2, with the distance between the silencer groove 1 and the two adjacent weld grooves 2 being equal. This improves the uniformity of mass distribution on the disk 3, further reducing aerodynamic noise during the rotation of the crossflow impeller. Furthermore, positioning the silencer groove 1 centrally between two adjacent weld grooves 2 also facilitates machining of the silencer groove 1.

[0059] It should be noted that the center of each of the aforementioned silencer grooves 1 may refer to the center of the arc of the silencer groove 1 on the side close to the center of the middle section fan blade. The center of each of the aforementioned welding grooves 2 may refer to the center of the arc of the welding groove 2 on the side close to the center of the middle section fan blade.

[0060] As shown in Figures 6 and 7, the cross-sectional profile of the muffler groove 1, taken parallel to the axial direction of the mid-section blade, is U-shaped. In a specific application example, the depth h of the muffler groove 1 satisfies the following conditions: 0.5mm ≤ h ≤ 2mm. This design ensures that the depth h of the muffler groove 1 is neither too small to significantly reduce aerodynamic noise, nor too large to affect the strength of the disc 3 and the mid-section blade.

[0061] As shown in FIG5 , the distance d between the aforementioned silencer groove 1 and the adjacent welding groove 2 satisfies the following condition: 1 mm ≤ d ≤ 1.2 mm. In this way, the distance d between the silencer groove 1 and the adjacent welding groove 2 is neither too small to be easily deformed nor too large to make the silencer groove 1 have an insignificant effect in reducing aerodynamic noise.

[0062] As shown in FIG5 , in a cross section perpendicular to the axial direction of the middle section fan blade, the cross-sectional profile of the aforementioned silencer groove 1 has a relative first curve 101 and a second curve 102. The first curve 101 and the second curve 102 are connected by a first arc 103 on the side close to the center of the middle section fan blade. The first curve 101 and the second curve 102 are connected by a second arc 104 on the side away from the center of the middle section fan blade. As shown in FIG4 , the distance between the center of the first arc 103 and the center of the middle section fan blade is equal to the inner diameter D1 of the blade 4, that is, the center of the first arc 103 of the cross-sectional profile of each silencer groove 1 is located on the circle of the inner diameter D1 of the blade 4. The distance between the center of the aforementioned second arc 104 and the center of the middle section fan blade is D2, and the outer diameter of the blade 4 is D3, wherein D2≤0.95D3.

[0063] In the above example, when there are two or more silencer grooves 1, the center of the first arc 103 of the cross-sectional profile of each silencer groove is located on the circle of the inner diameter D1 of the blade 4. In this way, when machining each silencer groove 1, machining can be started from the circle of the inner diameter D1 of the blade 4, so that the machining starting point of each silencer groove 1 is consistent, thereby facilitating the machining of each silencer groove 1. In addition, by ensuring that D2 ≤ 0.95D3, the machining position of the second arc 104 can be controlled to prevent the second arc 104 from being over-machined and deformed.

[0064] It should be noted here that: in the cross-section perpendicular to the axial direction of the middle-section fan blade, the distance D2 between the center of the second arc 104 of the cross-sectional contour of each of the two silencer grooves 1 and the center of the middle-section fan blade is not equal, so that the area of ​​the cross-sectional contour of each silencer groove 1 is different, thereby achieving the purpose of further changing the frequency of the airflow colliding with the wall of the disk 3 when the cross-flow fan blade rotates, and further reducing the aerodynamic noise when the cross-flow fan blade rotates.

[0065] In a specific application example, as shown in FIG5 , the first curve 101 is a convex curve, and the convex curve and the convex surface 43 of the blade are both convex in the same direction. The second curve 102 can be a concave curve, and the concave curve and the concave surface 44 of the blade are both concave in the same direction.

[0066] In the above example, through the above arrangement, the silencer groove 1 can have an outer shape similar to that of the blade 4. Since the outer shape of the blade 4 can silence and reduce the noise of the airflow passing through, the silencer groove 1 having a similar shape can cooperate with the outer shape of the blade 4 to further silence and reduce the noise of the airflow passing through. FIG9 shows a comparison of the noise effects of an existing crossflow fan blade and a crossflow fan blade of the present disclosure using a silencer groove of the above shape. As can be seen from FIG9, under the same air volume, the crossflow fan blade of the present disclosure using a silencer groove of the above shape has lower noise, and can generally reduce the fan blade noise by at least 1-1.5dBA.

[0067] As shown in Figure 5, in the direction close to the center of the middle section of the fan blade, the distance L between the first curve 101 and the second curve 102 gradually increases. In this way, on the path of the airflow passing through the silencer groove 1, the volume of the silencer groove 1 gradually increases, which can play a role in gradually expanding the airflow, thereby further silencing and reducing the noise of the airflow passing through.

[0068] In a specific application example, the distance L between the first curve 101 and the second curve 102 satisfies: 0.6mm≤L≤2.85mm, so that the distance L between the first curve 101 and the second curve 102 is neither too large to affect the strength of the blade 4 nor too small to make the muffler groove 1 have an insignificant effect on reducing aerodynamic noise.

[0069] As shown in Figure 8, in a cross-section perpendicular to the axial direction of the mid-section blade, the centerline of the cross-sectional profile of blade 4 comprises two or more consecutively connected arcs, each with a different radius and central angle. The center O of blade 4 at its maximum thickness lies on the arc facing away from the center of the mid-section blade. Furthermore, as it approaches the center of the mid-section blade, the thickness of blade 4 gradually increases to a maximum and then gradually decreases.

[0070] In a specific application example, as shown in Figure 8, in a cross section perpendicular to the axial direction of the mid-section wind blade, the center line of the cross-sectional profile of the aforementioned blade 4 is composed of a first a-arc 41 and a second a-arc 42 connected in sequence. The center angle of the first a-arc 41 is θ1, and the radius of the first a-arc 41 is r1. The center angle of the second a-arc 42 is θ2, and the radius of the first a-arc 41 is r2. Among them, the radii and center angles of the first a-arc 41 and the second a-arc 42 are different. That is, θ1 is not equal to θ2, and r1 is not equal to r2. The first a-arc 41 is away from the center of the mid-section wind blade relative to the second a-arc 42, and the center of the maximum thickness of the blade 4 is located on the first a-arc 41.

[0071] In the above example, by designing the shape of the blade 4, the airflow inlet angle can be changed and the separation vortex on the surface of the blade 4 can be reduced, thereby reducing power loss and increasing air volume, reducing the vortex noise on the surface of the blade 4, and further improving the noise effect.

[0072] One embodiment of the present disclosure also provides a crossflow blade, which may include any of the aforementioned mid-section blades. Because the crossflow blade utilizes the aforementioned mid-section blade, a silencer groove 1 is provided between two adjacent weld grooves 2, allowing airflow to flow through the silencer groove 1 during rotation. This silencer groove 1 can change the frequency of airflow collisions with the wall surface of the disc 3, reducing aerodynamic noise during rotation. When the crossflow blade is used in an air conditioner, this can improve the noise and sound quality of the air conditioner. Furthermore, the centerline of the silencer groove 1 is parallel to the axis of the mid-section blade. When the crossflow blade rotates, airflow flows radially into the interior of the blade. The centerline of the silencer groove 1 intersects perpendicularly with the direction of airflow, forming a silencer cavity structure that silences the airflow passing through it, further reducing noise transmission. Furthermore, by providing the silencer groove 1 in the disc 3, the weight of the disc 3 is reduced, thereby reducing the power consumption of the crossflow blade. When the crossflow blade is used in an air conditioner, the power of the air conditioner can be reduced.

[0073] An embodiment of the present disclosure further provides an air conditioner, which may include any of the above-mentioned cross-flow blades. Because the air conditioner uses the above-mentioned cross-flow blades, aerodynamic noise can be reduced.

[0074] For ease of understanding, the overall structure of the present disclosure is described below, and its working principle is explained.

[0075] The present disclosure is to design a mid-section fan blade and a cross-flow fan blade using the mid-section fan blade, and the cross-flow fan blade can be used on an air conditioner. The mid-section fan blade disclosed in the present disclosure is provided with a plurality of spaced silencer grooves 1 on the side of the disc 3 away from the blade 4. The silencer grooves 1 are of different sizes. The silencer grooves 1 can be a cut structure formed by cutting. The silencer groove 1 is an inward concave structure on the disc 3 except for the welding groove 2. The silencer groove 1 is arranged between two adjacent welding grooves 2. The angle between the centers of the two adjacent welding grooves 2 and the line connecting the center of the mid-section fan blade is β, wherein the silencer groove 1 is only arranged between two welding grooves 2 with β≥9°. The angle between the two silencer grooves 1 is designed in association with the angle between the three adjacent front and rear welding grooves 2. The silencer groove 1 is stretched to a depth h along the axis direction of the cross-flow fan blade toward the side of the disc 3 close to the blade 4. In a cross section perpendicular to the axial direction of the mid-section fan blade, the cross-sectional profile of the silencer groove 1 has a first curve 101 and a second curve 102 relative to each other. The first curve 101 and the second curve 102 are connected by a first arc 103 on the side close to the center of the mid-section fan blade, and the first curve 101 and the second curve 102 are connected by a second arc 104 on the side away from the center of the mid-section fan blade. The first curve 101 is a convex curve, and the second curve 102 is a concave curve. The shapes of the first curve 101 and the second curve 102 are designed to be irregular curves. The distance between the center of the second arc 104 and the center of the mid-section fan blade is less than the outer diameter of the outer circle of the welding groove 2.

[0076] A blade 4 is provided on the side of the aforementioned disk 3 facing away from the silencer groove 1. In a cross-section perpendicular to the axial direction of the mid-section blade, the centerline of the cross-sectional profile of blade 4 is a non-circular structure consisting of two or more circular arcs. The center of blade 4 at its maximum thickness is located near the front end of the centerline, which is the end of the centerline away from the center of the mid-section blade. The weld groove 2 is designed to have the same external structure as blade 4, and the silencer groove 1 and weld groove 2 are spaced apart.

[0077] The newly designed blade structure can improve the boundary layer and surface airflow separation of the blade surface, thereby reducing power loss, increasing air volume, and reducing eddy current noise of the air conditioner.

[0078] By adopting the crossflow fan blade designed in the present disclosure and designing the silencer groove 1 structure, the weight of the crossflow fan blade itself can be reduced, thereby reducing the power of the air conditioner and at the same time reducing the fan blade noise by at least 1-1.5dBA.

[0079] The above description is only a preferred embodiment of the present disclosure and does not limit the patent scope of the present disclosure. All equivalent structural transformations made by using the contents of the present disclosure and the drawings under the inventive concept of the present disclosure, or direct / indirect application in other related technical fields are included in the patent protection scope of the present disclosure.

Claims

1. A mid-section wind blade, comprising a disc (3), the disc (3) having a first side (31) and a second side (32) opposite to each other, the first side (31) being provided with a blade (4), the second side (32) being provided with a welding groove (2) for welding with a blade (4) on another mid-section wind blade, the number of the welding grooves (2) being more than two and being arranged in sequence and spaced apart along the circumference of the disc (3); in, The second side (32) is also provided with a silencer groove (1), and the silencer groove (1) is located between two adjacent welding grooves (2).

2. The middle section wind blade according to claim 1, wherein: The number of the muffler grooves (1) is more than two, and they are arranged in sequence and at intervals along the circumference of the disc (3); In a cross section perpendicular to the axial direction of the middle-section fan blade, the cross-sectional profile areas of each noise-absorbing groove (1) are different.

3. The middle section wind blade according to claim 2, wherein: The angle between the center of two adjacent welding grooves (2) and the connecting line of the center of the middle section wind blade is β, wherein the muffler groove (1) is provided only between two welding grooves (2) with β≥9°; Alternatively, the above-mentioned sound-absorbing groove (1) is provided between each two adjacent welding grooves (2).

4. The middle section wind blade according to claim 1, wherein: The three welding grooves (2) arranged in sequence along the circumference of the disc (3) are respectively a first welding groove (21), a second welding groove (22) and a third welding groove (23); The muffler groove (1) comprises a first muffler groove (11) located between a first welding groove (21) and a second welding groove (22), and a second muffler groove (12) located between the second welding groove (22) and a third welding groove (23); In a cross section perpendicular to the axial direction of the middle section fan blade, the angle between the center of the first silencer groove (11) and the center of the second silencer groove (12) and the center of the middle section fan blade is θ, the angle between the center of the first welding groove (21) and the center of the second welding groove (22) and the center of the middle section fan blade is β1, and the angle between the center of the second welding groove (22) and the center of the third welding groove (23) and the center of the middle section fan blade is β2; wherein θ=(β1+β2) / 2.

5. The middle section wind blade according to claim 1, wherein: The depth h of the noise reduction groove (1) satisfies: 0.5 mm ≤ h ≤ 2 mm.

6. The middle section wind blade according to claim 1, wherein: The distance d between the silencer groove (1) and the adjacent welding groove (2) satisfies: 1 mm ≤ d ≤ 1.2 mm.

7. The middle section wind blade according to claim 1, wherein: The depth h of the silencer groove (1) satisfies: 0.5 mm ≤ h ≤ 2 mm, and the distance d between the silencer groove (1) and an adjacent welding groove (2) satisfies: 1 mm ≤ d ≤ 1.2 mm.

8. The middle section wind blade according to claim 1, wherein: In a cross section perpendicular to the axial direction of the middle-section fan blade, the cross-sectional profile of the silencer groove (1) has a first curve (101) and a second curve (102) opposite to each other, the first curve (101) and the second curve (102) being connected by a first arc (103) on a side close to the center of the middle-section fan blade, and the first curve (101) and the second curve (102) being connected by a second arc (104) on a side away from the center of the middle-section fan blade; The distance between the center of the first arc (103) and the center of the middle-section fan blade is equal to the inner diameter D1 of the blade (4), the distance between the center of the second arc (104) and the center of the middle-section fan blade is D2, and the outer diameter of the blade (4) is D3, wherein D2≤0.95D3.

9. The middle section wind blade according to claim 8, wherein: The first curve (101) is a convex curve, and the convex curve and the convex surface of the blade (4) have the same convex direction.

10. The middle section wind blade according to claim 8, wherein: The second curve (102) is a concave curve, and the concave directions of the concave curve and the concave surface of the blade (4) are consistent.

11. The middle section wind blade according to claim 8, wherein: The first curve (101) is a convex curve, and the convex direction of the convex curve is consistent with the convex surface of the blade (4); and the second curve (102) is a concave curve, and the concave direction of the concave curve is consistent with the concave surface of the blade (4).

12. The middle section wind blade according to claim 8, wherein: In the direction close to the center of the middle-section wind blade, the first curve (101) is The distance L between the first curve (101) and the second curve (102) gradually increases, and the distance L between the first curve (101) and the second curve (102) satisfies: 0.6 mm≤L≤2.85 mm.

13. The middle section wind blade according to any one of claims 1 to 12, wherein: In a cross section perpendicular to the axial direction of the middle-section wind blade, the center line of the cross-sectional profile of the blade (4) includes more than two arcs connected in sequence, and the radius and central angle of each arc are different, wherein the center of the maximum thickness of the blade (4) is located on the arc on the side of the center line away from the center of the middle-section wind blade; and along the direction approaching the center of the middle-section wind blade, the thickness of the blade (4) gradually increases to a maximum and then gradually decreases.

14. A crossflow fan blade, comprising the middle-section fan blade according to any one of claims 1 to 13.

15. An air conditioner comprising the cross-flow blade according to claim 14.

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