Air outlet grille, axial flow fan and household appliance

Abstract

The invention relates to the technical field of axial flow fans, in particular to an air outlet grille, an axial flow fan and a household appliance. The air outlet grille aims at solving the problems that air flow resistance can be increased by the air outlet grille in the related technology, air volume loss of the axial flow fan is serious, and noise is increased. Therefore, the air outlet grille comprises a grille body provided with a fixing area extending in the circumferential direction of the grille body; the multiple flow guide ribs are arranged in the fixed area at intervals in the circumferential direction of the grille body; wherein the inclination angle of the flow guide rib and the air inlet direction of the air outlet grid form a preset angle, the upper surface of the flow guide rib is a concave arc-shaped surface, the flow guide rib comprises a windward end face and a leeward end face, the thickness of the flow guide rib is gradually increased from the windward end face to the leeward end face, and the flow guide rib is gradually narrowed at the leeward end face. According to the air outlet grille, the air outlet flow direction of the fan blades can be well guided, the resistance of the air outlet grille to airflow is reduced, and therefore the air volume loss and noise are reduced.

Description

Technical Field

[0001] The present application relates to the technical field of axial flow fans, and in particular to an air outlet grille, an axial flow fan and household electrical appliances. Background Art

[0002] At present, most axial flow fans of household appliances are equipped with air outlet grilles. For example, the axial flow fan of an air conditioner outdoor unit is provided with an air outlet grille. The fan blades of the axial flow fan rotate to drive the air flow through the outdoor heat exchanger of the air conditioner outdoor unit and then flow out of the air conditioner outdoor unit through the air outlet grille.

[0003] The air outlet grille in the related art is mainly used to enhance safety and prevent users from contacting the high-speed rotating fan blades. However, the air outlet grille in the related art increases the resistance of the air flow, causing serious air volume loss of the axial flow fan and increasing noise, which affects the user experience.

[0004] Accordingly, the art needs a new technical solution to solve the above problems. Summary of the invention

[0005] In order to solve at least one of the above problems in the prior art, that is, to solve the problem that the air outlet grille in the related art increases the resistance of the air flow, resulting in serious air volume loss of the axial flow fan and increased noise.

[0006] In a first aspect, the present application provides an air outlet grille, comprising: a grille body, provided with a fixed area extending along the circumference of the grille body; a plurality of guide ribs, arranged in the fixed area at intervals along the circumference of the grille body; wherein the inclination angle of the guide rib is a preset angle with the air inlet direction of the air outlet grille, the upper surface of the guide rib is an inwardly concave arc surface, the guide rib comprises a windward end face and a leeward end face, and the thickness of the guide rib gradually increases from the windward end face to the leeward end face, and gradually narrows at the leeward end face.

[0007] In some embodiments, the windward end surface of the guide rib and the leeward end surface of the guide rib are both convex arc surfaces, and the radius of the arc corresponding to the windward end surface is smaller than the radius of the arc corresponding to the leeward end surface.

[0008] In some embodiments, the guide rib includes a strip cross section perpendicular to the length direction of the guide rib; the strip cross section includes a windward leading edge, a maximum thickness position, and a gradually thickening section located between the windward leading edge and the maximum thickness position; wherein the length of the orthographic projection of the gradually thickening section in the axial direction of the air outlet grille is L 1 The length of the orthographic projection of the strip cross section in the axial direction is L 2 , L 1 / L 2 =(0.5~1).

[0009] In some embodiments, the maximum thickness of the strip cross section is B 1 , B 1 / L 2 =(0.2~0.5); and / or, the strip cross-section includes a first curve located on the windward side and an upper curve connected to the first curve; the tangent at the connection between the first curve and the upper curve is a first tangent, and the angle between the first tangent and the wind inlet direction is in the range of [-10°, 10°]; and / or, the strip cross-section includes a second curve close to the leeward side, the tangent at the connection between the second curve and the upper curve is a second tangent, and the angle between the second tangent and the axial direction is in the range of 0°~10°.

[0010] In some embodiments, the strip-shaped cross-section includes a lower mold line, and the lower mold line is a straight line or a convex curve.

[0011] In some embodiments, the center of the air outlet grille protrudes toward the leeward side; or, the center of the air outlet grille protrudes toward the leeward side, and the angle between the radial direction and the vertical direction of the air outlet grille ranges from 1° to 5°.

[0012] In some embodiments, the grille body includes a central disk, an outer frame, and a plurality of annular ribs with different inner diameters arranged between the outer frame and the central disk, wherein the plurality of annular ribs are arranged concentrically with the outer frame, wherein the fixed area is defined between the central disk and the annular ribs, between adjacent annular ribs, and between the annular ribs and the outer frame.

[0013] In some embodiments, the outer frame is configured to be circular or square; and / or, the annular rib is configured to be circular, square or semi-enclosed; and / or, the air outlet grille is configured to be a plane or an arc surface; and / or, fixing holes and buckles are provided on the outer frame.

[0014] In a second aspect, the present application provides an axial flow fan, comprising an axial flow fan and the above-mentioned air outlet grille, wherein the air outlet grille is arranged on the air outlet side of the axial flow fan.

[0015] In a third aspect, the present application provides a household appliance, which includes an axial flow fan and the above-mentioned air outlet grille, and the air outlet grille is arranged on the air outlet side of the axial flow fan.

[0016] The air inlet direction of the air outlet grille is the air outlet direction of the blades of the axial flow fan. The inclination angle of the guide ribs of the air outlet grille is a preset angle with the air inlet direction of the air outlet grille, which can make the guide ribs adapt to the air outlet angle of the blades and reduce the resistance of the guide ribs to the air outlet of the blades. The upper surface of the guide rib is a concave arc surface, which can better guide the direction of the airflow. From the windward end face of the guide rib to the leeward end face of the guide rib, the thickness of the guide rib gradually increases, that is, the thickness of the windward end face is relatively small, which can not only further reduce the resistance to the air outlet of the blades and maximize the effective air inlet area of ​​the air outlet grille, but also better adapt to the air outlet angle of the blades and guide the airflow more smoothly to the guide ribs. The thickness of the guide ribs near the leeward end face is larger and gradually narrows at the leeward end face, which can guide the flow direction of the airflow, so that the airflow flows out smoothly, thereby reducing the trailing edge shedding vortex. In addition, the greater thickness of the leeward end surface can prevent users from inserting fingers or foreign objects into the axial flow fan, which is beneficial to improving the safety of the axial flow fan. Under the premise of adopting the above technical solution, the air outlet grille provided in this application can better guide the flow direction of the fan blades, reduce the resistance of the air outlet grille to the airflow, thereby reducing air volume loss and noise. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The air outlet grille, battery pack, locking mechanism and vehicle of the present application are described below with reference to the accompanying drawings. In the accompanying drawings:

[0018] Figure 1 A schematic diagram of the structure of the air outlet grille of the present application;

[0019] Figure 2 A schematic diagram of the structure of the guide rib of the present application;

[0020] Figure 3 for Figure 1 A partially enlarged structural schematic diagram of the center air outlet grille;

[0021] Figure 4 for Figure 3 Schematic diagram of the structure of the middle section BB;

[0022] Figure 5 for Figure 1 A side view of the center air grille;

[0023] Figure 6 Another structural schematic diagram of the air outlet grille of the present application;

[0024] Figure 7 Another structural schematic diagram of the air outlet grille of the present application;

[0025] Figure 8 Another structural schematic diagram of the air outlet grille of the present application;

[0026] Fig. 9 for Figure 1 Schematic diagram of the structure of the center air grille from another perspective.

[0027] Reference numerals list

[0028] 100, grille body; 101, fixed area; 102, center disk; 103, outer frame; 104, annular ribs; 200, guide ribs; 201, windward end face; 202, leeward end face; 203, strip section; 2031, windward leading edge; 2032, maximum thickness position; 2033, gradually thickening section; 2034, first curve; 2035, upper curve; 2036, second curve; 2037, lower profile line. DETAILED DESCRIPTION

[0029] The preferred embodiments of the present application are described below with reference to the accompanying drawings. It should be understood by those skilled in the art that these embodiments are only used to explain the technical principles of the present application and are not intended to limit the scope of protection of the present application. For example, although the following embodiments of the present application are described in conjunction with an air conditioner outdoor unit, this is not intended to limit the scope of protection of the present application. Without departing from the principles of the present application, the air outlet grille and axial flow fan of the present application can also be applied to other household appliances.

[0030] It should be noted that in the description of the present application, the terms "middle", "upper", "lower", "vertical", "inner", "outer" and the like indicating directions or positional relationships are based on the directions or positional relationships shown in the drawings, which are only for the convenience of description, and do not indicate or imply that the device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present application. In addition, the terms "first" and "second" are used for descriptive purposes only and cannot be understood as indicating or implying relative importance. "Multiple" means two or more.

[0031] In addition, it should be noted that in the description of this application, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For those skilled in the art, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0032] At present, most axial flow fans of household appliances are equipped with air outlet grilles. For example, the axial flow fan of an air conditioner outdoor unit is provided with an air outlet grille. The fan blades of the axial flow fan rotate to drive the air flow through the outdoor heat exchanger of the air conditioner outdoor unit and then flow out of the air conditioner outdoor unit through the air outlet grille.

[0033] The air outlet grille in the related art is mainly used to enhance safety and prevent users from contacting the high-speed rotating fan blades. However, the air outlet grille in the related art increases the resistance of the air flow, causing serious air volume loss of the axial flow fan and increasing noise, which affects the user experience.

[0034] In order to reduce the resistance of the air outlet grille to the air flow and reduce noise, the present application provides an air outlet grille, an axial flow fan and a household appliance.

[0035] In a first aspect, the present application provides an air outlet grille.

[0036] Combination Figure 1 and Figure 2 As shown, the air outlet grille provided in the present application includes a grille body 100 and a plurality of guide ribs 200 .

[0037] The grille body 100 is provided with a fixing area 101 extending along the circumference of the grille body 100. A plurality of guide ribs 200 are arranged in the fixing area 101 at intervals along the circumference of the grille body 100.

[0038] Among them, the inclination angle of the guide rib 200 is a preset angle with the air inlet direction of the air outlet grille, the upper surface of the guide rib 200 is a concave arc surface, the guide rib 200 includes a windward end face 201 and a leeward end face 202, and the thickness of the guide rib 200 gradually increases from the windward end face 201 to the leeward end face 202, and gradually narrows at the leeward end face 202.

[0039] The air inlet direction of the air outlet grille is the air outlet direction of the blades of the axial flow fan. The inclination angle of the guide rib 200 of the air outlet grille is a preset angle with the air inlet direction of the air outlet grille, which can make the guide rib 200 adapt to the air outlet angle of the blades and reduce the resistance of the guide rib 200 to the air outlet of the blades. The upper surface of the guide rib 200 is a concave arc surface, which can better guide the flow direction of the airflow. From the windward end surface 201 of the guide rib 200 to the leeward end surface 202 of the guide rib 200, the thickness of the guide rib 200 gradually increases, that is, the thickness of the windward end surface 201 is relatively small, which can not only further reduce the resistance to the air outlet of the blades and maximize the effective air inlet area of ​​the air outlet grille, but also better adapt to the air outlet angle of the blades and guide the airflow to the guide rib 200 more smoothly. The guide rib 200 has a larger thickness near the leeward end surface 202 and gradually narrows at the leeward end surface 202, which can guide the flow direction of the airflow so that the airflow flows out smoothly, thereby reducing the trailing edge shedding vortex. In addition, the larger thickness of the leeward end surface 202 can prevent users from inserting their fingers or foreign objects into the axial flow fan, which is beneficial to improving the safety of the axial flow fan. Under the premise of adopting the above technical solution, the air outlet grille provided in this application can better guide the flow direction of the fan blade air outlet, reduce the resistance of the air outlet grille to the airflow, thereby reducing the air volume loss and noise.

[0040] In some embodiments, in combination Figure 2 As shown, the windward end surface 201 of the guide rib 200 and the leeward end surface 202 of the guide rib 200 are both convex arc surfaces, and the radius of the arc corresponding to the windward end surface 201 is smaller than the radius of the arc corresponding to the leeward end surface 202 .

[0041] After the airflow contacts the curved windward end face 201, it begins to split. The separated airflow flows along the curved surface to the upper and lower sides of the guide rib 200 under the action of the wall attachment effect. By designing the windward end face 201 as a convex curved surface, the airflow can be better guided. By designing the leeward end face 202 as a convex curved surface, it is beneficial to improve safety and prevent users from being scratched by contacting the air outlet grille. The radius of the arc corresponding to the windward end face 201 is smaller than the radius of the arc corresponding to the leeward end face 202. The guide rib 200 has a structure in which the windward end face 201 is thin and the leeward end face 202 is thick. The thin windward end face 201 can adapt to a variety of wind outlet angles and reduce the resistance to the airflow. The thick leeward end face 202 can prevent users from inserting their fingers into the air outlet grille and pass the safety finger test experiment.

[0042] In some embodiments, in combination Figure 3 and Figure 4 As shown, the guide rib 200 includes a strip cross section 203 perpendicular to the length direction of the guide rib 200. The strip cross section 203 includes a windward leading edge 2031, a maximum thickness position 2032, and a gradually thickening section 2033 located between the windward leading edge 2031 and the maximum thickness position 2032. The length of the orthographic projection of the gradually thickening section 2033 in the axial direction of the air outlet grille is L. 1 , the length of the orthographic projection of the strip section 203 in the axial direction is L 2 , L 1 / L 2 =(0.5~1).

[0043] By adding L 1 and L 2 If the ratio of is limited to the above range, the thickness of the guide rib 200 can gradually increase from the windward end to the leeward end and gradually narrow at the leeward end, thereby reducing the resistance to the airflow and reducing the trailing edge vortex. If the maximum thickness position 2032 is too close to the windward end of the strip section 203, it will cause serious wind blocking and excessive wind resistance. If the maximum thickness position 2032 is too close to the leeward end of the strip section 203, it will cause a large trailing edge vortex. For example, L 1 / L 2 =0.5, 0.6, 0.7, 0.8, 0.9 or 1, etc.

[0044] In some embodiments, the maximum thickness of the strip cross-section 203 is B 1 , B1 / L 2 =(0.2-0.5). By setting the maximum thickness B of the strip section 203 1 and the length L of the orthographic projection of the strip section 203 in the axial direction 2 Limiting to the above range is helpful to reduce air volume loss and noise.

[0045] For example, B 1 / L 2 =0.2, 0.3, 0.4 or 0.5, etc.

[0046] In some embodiments, in combination Figure 4 As shown, the strip cross section 203 includes a first curve 2034 located on the windward side and an upper curve 2035 connected to the first curve 2034. The tangent line at the connection between the first curve 2034 and the upper curve 2035 is the first tangent line l 1 , the first tangent line l 1 The angle α between the wind direction 1 The value range of is [-10°, 10°]. Such an arrangement can make the windward end surface of the guide rib 200 as parallel to the air inlet direction of the air outlet grille as possible, thereby reducing the resistance of the air outlet grille to the airflow.

[0047] For example, the first tangent line l 1 The angle α between the wind direction 1 The values ​​can be -10°, -7°, -5°, -3°, -1°, -0°, 2°, 5°, 6°, -8° or 10° etc.

[0048] In some embodiments, in combination Figure 4 As shown, the strip cross section 203 includes a second curve 2036 close to the leeward side, and the tangent line at the connection between the second curve 2036 and the upper curve 2035 is the second tangent line l 2 , the second tangent l 2 The angle α with the axis 2 The value range of is 0°~10°. 2 The angle α with the axis 2 Limiting the range to the above is beneficial to making the air flow flow out along the axial direction of the air outlet grille and reducing the trailing edge vortex shedding.

[0049] In some embodiments, in combination Figure 4 As shown, the strip cross section 203 includes a lower mold line 2037, which is a straight line or a convex curve. By setting the lower mold line 2037 as a straight line or a convex curve, the air conditioner ensures that the airflow flows along the lower mold line 2037 and will not separate from the guide rib 200.

[0050] In some embodiments, in combination Figure 1 and Figure 5 As shown, the center of the air outlet grille protrudes toward the leeward side. By setting the air outlet grille to be convex, the strength of the air outlet grille can be improved, and the air outlet grille is prevented from being depressed toward the side where the fan blades are located due to force, which affects the normal operation of the fan blades.

[0051] In some embodiments, in combination Figure 1 and Figure 5 As shown, the center of the air outlet grille protrudes toward the leeward side, and the angle α between the radial direction and the vertical direction of the air outlet grille 3 The value range of is 1°~5°. By setting the air outlet grille to a convex shape and α 3 Limiting the air outlet grille to the above range can not only improve the strength of the air outlet grille, prevent the air outlet grille from being depressed toward the side where the fan blades are located due to force, thereby affecting the normal operation of the fan blades, but also avoid occupying too large an area.

[0052] For example, the angle α between the radial direction and the vertical direction of the air outlet grille is 3 The value can be 1°, 2°, 3°, 4° or 5°, etc.

[0053] In some embodiments, in combination Figure 1 As shown, the grille body 100 includes a central disc 102, an outer frame 103, and a plurality of annular ribs 104 with different inner diameters arranged between the outer frame 103 and the central disc 102, and the plurality of annular ribs 104 are arranged concentrically with the outer frame 103. Among them, a fixing area 101 is defined between the central disc 102 and the annular ribs 104, between adjacent annular ribs 104, and between the annular ribs 104 and the outer frame 103. The central disc 102, the outer frame 103, and the outer frame 103 and the central disc 102 constitute the grille body 100, which plays the role of supporting and fixing the guide ribs. Since the guide ribs 200 are arranged in a divergent shape, the distance between two adjacent guide bars 200 becomes larger and larger along the edge of the air outlet grille from the center of the air outlet grille. By arranging multiple annular ribs 200 to enclose multiple fixed areas 101, it is convenient to make the guide ribs 200 evenly spread over the grille body 100. At the same time, the maximum distance between two adjacent guide bars 200 is controlled within a certain range to prevent users from putting their hands into the grille body.

[0054] In some embodiments, in combination Figure 1 , Figure 6 and Figure 7 As shown, the outer frame 103 is set to be circular or square, and can be flexibly set according to needs.

[0055] In some embodiments, in combination Figure 1 , Figure 6 and Figure 7 As shown, the annular rib is set to be circular, square or semi-enclosed, and can be flexibly set according to needs.

[0056] In some embodiments, in combination Figure 1 and Figure 8 As shown, the air outlet grille is set to a plane or an arc surface. In this way, it can be adapted to various shapes of home appliances, improving the universality of the air outlet grille. Here, the plane is relative to the arc surface, and the center of the air outlet grille slightly protruding toward the leeward side is also called a plane.

[0057] In some embodiments, the outer frame is provided with fixing holes and buckles, so as to facilitate fixing the air outlet grille to the air outlet side of the axial flow fan.

[0058] Specifically, combined Figure 1 and Fig. 9 As shown, two recessed parts are symmetrically arranged on the outer frame 103, each recessed part is formed with a groove, and a through hole is opened in the groove for screws to pass through. The recessed part is integrally formed with the outer frame 103 and a supporting rib is formed at the bottom, and the recessed part is flush with the windward side of the outer frame 103. A plurality of buckles are protruding outwardly on the windward side of the outer frame 103, and the buckles are used to rotate and snap with the outdoor unit housing. There are 6 buckles, and the 6 buckles are evenly distributed along the circumference of the outer frame 103. A plurality of protruding structures integrally formed with the outer frame 103 are also arranged on the windward side of the outer frame 103 along the circumference, and the support and clamping between the outer frame 103 and the front panel after the rotational snap connection are realized by the protruding structure. The height of the protruding structure is less than 2mm.

[0059] When applied to an air conditioner outdoor unit, the air outlet grille is installed on the front panel of the air conditioner outdoor unit housing, and an air outlet is provided on the front panel. The air outlet grille is provided on the arc-shaped clamping hole provided at the air outlet by means of a buckle, and is fastened to the studs symmetrically provided at the air outlet of the front panel by means of screws passing through the through holes of the recessed portion. There are 6 arc-shaped clamping holes, and the 6 clamping holes are evenly distributed along the air outlet.

[0060] The air outlet grille of this application was experimentally tested, as follows: Table 1

[0061] Table 1 Figure 1 The air outlet grille shown is used in the outdoor unit of the air conditioner. Figure 1 As shown, the air volume loss is reduced from 3% to 14% to 0.5% to 1%, and the noise is reduced by 0.5dB to 1dB. Table 2 plan Speed, rpm <![CDATA[Air volume, m 3 / h]]> Air volume loss percentage compared to no air grille No air grille 500 404.3 Original plan 500 340.8 15.7％ This program 500 396.2 2.0％

[0062] Table 2 Figure 8 The air outlet grille shown is applied to a heat pump water heater, combined with Figure 8 As shown, the air volume loss is reduced from 15.7% to 2.0%.

[0063] In the second aspect, the present application provides an axial flow fan, which includes an axial flow fan and the above-mentioned air outlet grille, which is arranged on the air outlet side of the axial flow fan. Under the premise of adopting the above-mentioned air outlet grille, the axial flow fan provided by the present application can better guide the flow direction of the air outlet of the fan blades, reduce the resistance of the air outlet grille to the airflow, thereby reducing the air volume loss and noise.

[0064] In a third aspect, the present application provides a household appliance, wherein the axial flow fan comprises an axial flow fan and the above-mentioned air outlet grille, and the air outlet grille is arranged on the air outlet side of the axial flow fan. Under the premise of adopting the above-mentioned air outlet grille, the household appliance provided by the present application can better guide the flow direction of the air outlet of the fan blades, reduce the resistance of the air outlet grille to the airflow, thereby reducing the air volume loss and noise.

[0065] The household appliances provided in this application include air conditioners and heat pump water heaters, etc.

[0066] It should be noted that the above preferred implementations are only used to illustrate the principles of the present application and are not intended to limit the scope of protection of the present application. Without departing from the principles of the present application, those skilled in the art may adjust the above settings so that the present application can be applied to more specific application scenarios.

[0067] Those skilled in the art will appreciate that, although some embodiments herein include certain features included in other embodiments but not other features, the combination of features of different embodiments is meant to be within the scope of the present application and form different embodiments. For example, in the claims of the present application, any one of the claimed embodiments may be used in any combination.

[0068] So far, the technical solutions of the present application have been described in conjunction with the preferred embodiments shown in the accompanying drawings. However, it is easy for those skilled in the art to understand that the protection scope of the present application is obviously not limited to these specific embodiments. Without departing from the principles of the present application, those skilled in the art can make equivalent changes or substitutions to the relevant technical features, and the technical solutions after these changes or substitutions will fall within the protection scope of the present application.

Claims

1. An air outlet grille, characterized in that: The air outlet grille comprises: A grille body is provided with a fixing area extending along the circumference of the grille body; A plurality of guide ribs are arranged at intervals in the fixing area along the circumference of the grille body; Among them, the inclination angle of the guide rib is a preset angle with the air inlet direction of the air outlet grille, the upper surface of the guide rib is a concave arc surface, the guide rib includes a windward end face and a leeward end face, and the thickness of the guide rib gradually increases from the windward end face to the leeward end face, and gradually narrows at the leeward end face.

2. The air outlet grille according to claim 1, characterized in that: The windward end surface of the guide rib and the leeward end surface of the guide rib are both convex arc-shaped surfaces, and the radius of the arc corresponding to the windward end surface is smaller than the radius of the arc corresponding to the leeward end surface.

3. The air outlet grille according to claim 1, characterized in that: The guide rib includes a strip section perpendicular to the length direction of the guide rib; the strip section includes a windward leading edge, a maximum thickness position, and a gradually thickening section located between the windward leading edge and the maximum thickness position; wherein the length of the orthographic projection of the gradually thickening section in the axial direction of the air outlet grille is L1, the length of the orthographic projection of the strip section in the axial direction is L2, and L1 / L2=(0.5~1).

4. The air outlet grille according to claim 3, characterized in that: The maximum thickness of the strip cross section is B1, B1 / L2=(0.2-0.5); and / or, The strip cross section includes a first curve located on the windward side and an upper curve connected to the first curve; a tangent line at the connection between the first curve and the upper curve is a first tangent line, and a value range of an angle between the first tangent line and the wind inlet direction is [-10°, 10°]; and / or, The strip cross section includes a second curve close to the leeward side, a tangent at a connection between the second curve and the upper curve is a second tangent, and a value range of an angle between the second tangent and the axial direction is 0° to 10°.

5. The air outlet grille according to claim 3, characterized in that: The strip-shaped cross section includes a lower mold line, and the lower mold line is a straight line or a convex curve.

6. The air outlet grille according to any one of claims 1 to 5, characterized in that: The center of the air outlet grille protrudes toward the leeward side; or, The center of the air outlet grille protrudes toward the leeward side, and the angle between the radial direction and the vertical direction of the air outlet grille is in the range of 1° to 5°.

7. The air outlet grille according to any one of claims 1 to 5, characterized in that: The grille body includes a central disk, an outer frame, and a plurality of annular ribs with different inner diameters arranged between the outer frame and the central disk, wherein the plurality of annular ribs are arranged concentrically with the outer frame, wherein the fixing area is defined between the central disk and the annular ribs, between adjacent annular ribs, and between the annular ribs and the outer frame.

8. The air outlet grille according to claim 7, characterized in that: The outer frame is configured as a circle or a square; and / or, The annular rib is configured in a circular, square or semi-enclosed shape; and / or, The air outlet grille is configured as a flat surface or an arc surface; and / or, The outer frame is provided with fixing holes and buckles.

9. An axial flow fan, characterized in that: The axial flow fan comprises an axial flow fan and an air outlet grille according to any one of claims 1 to 8, wherein the air outlet grille is arranged on the air outlet side of the axial flow fan.

10. A household appliance, characterized in that: The household appliance comprises an axial flow fan and an air outlet grille according to any one of claims 1 to 8, wherein the air outlet grille is arranged on an air outlet side of the axial flow fan.

Images