Fans and range hoods

Abstract

The present invention discloses a fan and a range hood, which include an impeller and a plurality of blades spaced apart along the circumference of the impeller. The blades are provided with a plurality of through holes, each of which penetrates the blade along the thickness direction of the blade, and the plurality of through holes are spaced apart along the length direction of the blade. The blade includes a leading edge and a trailing edge that are oppositely disposed along the width direction, the leading edge of the blade being disposed near the inner ring of the impeller, and the distance from the center of each through hole to the leading edge of the blade is less than or equal to half the width of the blade. In this solution, the through holes penetrate the blade along the thickness direction of the blade, and the pressure transmission through the through holes can reduce the pressure difference between the pressure surface and the non-pressure surface of the blade. The distribution of the holes is arranged according to the pressure difference distribution law on the blade, which can effectively reduce the pressure difference at different positions, improve the internal vortex, thereby reducing aerodynamic noise and improving the user experience.

Description

Technical Field

[0001] The present invention relates to the technical field of kitchen appliances, and in particular to a fan and a range hood. Background Art

[0002] Existing range hoods generate high operating noise levels, impacting user experience and comfort. To reduce noise, optimizing the existing fan system or the entire unit, or upgrading the product, is necessary. However, this approach doesn't directly improve the performance of existing products. Furthermore, product upgrades typically require changes to the fan system's dimensions, requiring re-molding and other processes, resulting in high R&D costs. Summary of the Invention

[0003] The technical problem to be solved by the present invention is to overcome the problems in the prior art of high noise in range hoods and high cost of upgrading the fan system, and to provide a fan and a range hood.

[0004] The present invention solves the above technical problems through the following technical solutions:

[0005] A fan comprises an impeller and a plurality of blades spaced apart along the circumference of the impeller, wherein the blades are provided with a plurality of through holes, each of the through holes passing through the blade along the thickness direction of the blade, and the plurality of through holes are spaced apart along the length direction of the blade;

[0006] The blade includes a leading edge and a trailing edge that are oppositely arranged along the width direction, and the leading edge of the blade is arranged close to the inner ring of the impeller;

[0007] The distance from the center of each through hole to the leading edge of the blade is less than or equal to half the width of the blade; and along the length direction of the blade, for any first area and second area where the through holes are provided, the first area is closer to the center line of the length direction of the blade relative to the second area, and the spacing between two adjacent through holes in the first area is less than the spacing between two adjacent through holes in the second area.

[0008] In this solution, the pressure distribution on the pressure side and non-pressure side of the blade is irregular. The maximum pressure difference on the blade occurs in the front half of the blade near the leading edge. The pressure is significantly higher at the center of the blade along its length, and the closer to the ends of the blade, the lower the pressure on the blade. In this solution, the through-holes penetrate the blade along its thickness. The pressure transfer through the through-holes can reduce the pressure difference between the pressure side and the non-pressure side of the blade. The distribution of the holes is set according to the pressure difference distribution pattern on the blade, which can effectively reduce the pressure difference at different positions, improve internal vortex, thereby reducing aerodynamic noise and improving user experience.

[0009] Preferably, the vertical distance from the center of the through hole to the leading edge of the blade is positively correlated with the vertical distance from the center of the through hole to the center line of the blade.

[0010] In this solution, the distribution of the through holes conforms to the distribution law of the pressure difference on the blade, which can reduce the pressure difference, improve the internal vortex, thereby reducing aerodynamic noise and improving user experience.

[0011] Preferably, the through holes are arranged along the length direction of the blade, from the center line of the blade to the end of the blade, and the distance between two adjacent through holes gradually increases.

[0012] In this solution, the pressure difference is large at the center line of the blade, and the closer to the two ends of the blade, the smaller the pressure difference. The distribution of the through holes is set according to the distribution law of the pressure difference on the blade, which can effectively reduce the pressure difference at different positions of the blade, improve the internal vortex, thereby reducing aerodynamic noise and improving user experience.

[0013] Preferably, the positions of the through holes are described using a Cartesian coordinate system, wherein the x-axis is on the center line of the blade, the y-axis is on the leading edge of the blade, the intersection of the x-axis and the y-axis is the coordinate origin, and the position distribution of the through holes satisfies the following formula:

[0014] x n =m+(n-1)D,y n =y1*Q (n-1) ;

[0015] Among them, the coordinates of the initial through hole center are (m, 0), the coordinates of the nth through hole center are (xn, yn), n is a positive integer; the value range of m is 4mm-9mm; the range of y1 is 6mm-10mm; Q is the geometric coefficient, the value range is 1-1.5, excluding 1; D is the arithmetic coefficient, the value range is 0.4-1.2.

[0016] In this solution, the through holes are distributed in a geometric progression in the y-axis direction and in an arithmetic progression in the x-axis direction. This arrangement conforms to the distribution law of the pressure difference on the blade and can effectively reduce the pressure difference of the blade.

[0017] Preferably, the through holes are symmetrically distributed along the midline of the length direction of the blade.

[0018] In this solution, the through holes are symmetrically distributed along the center of the blade, which can adapt to the distribution of the pressure difference of the blade and is conducive to reducing the pressure difference of the blade.

[0019] Preferably, along the length direction of the blade, the distance between the centers of two adjacent through holes is between 1 / 20L and 1 / 8L, wherein L is the length of the blade.

[0020] In this solution, the spacing between adjacent through holes is limited so that the through holes can reduce the pressure difference and reduce noise without affecting the strength of the blade body. If the spacing is too small, the through holes will be too densely distributed, affecting the strength of the blade. If the spacing is too large, it will not be conducive to reducing noise.

[0021] Preferably, the diameter of the through hole is 1.5 mm-3 mm.

[0022] In this solution, the diameter of the through hole is limited to between 1.5 mm and 3 mm, which effectively reduces the pressure difference and reduces noise without affecting the strength of the blade body.

[0023] Preferably, the blade further comprises a plurality of convex hulls, the through hole is provided at the bottom of the convex hull, the convex hull is provided with an opening on one side close to the leading edge of the blade, and the opening is connected to the through hole, and the plurality of convex hulls are spaced apart along the length direction of the blade;

[0024] The distance from the center of each convex hull to the leading edge of the blade is less than or equal to half the width of the blade; and along the length direction of the blade, for any first area and second area where the convex hull is provided, wherein the first area is closer to the midline of the length direction of the blade relative to the second area, the spacing between two adjacent convex hulls in the first area is smaller than the spacing between two adjacent convex hulls in the second area.

[0025] In this solution, a convex hull is provided according to the distribution law of the pressure difference on the blade, and a through hole is provided at the bottom of the convex hull, which can prevent the airflow from flowing back in the blade and further reduce the pressure difference of the blade.

[0026] Preferably, the outer periphery of the through hole is located within the orthographic projection of the convex hull on the upper surface of the blade.

[0027] In this solution, effective pressure transmission through the through hole can be ensured.

[0028] Preferably, the vertical distance from the center of the convex hull to the leading edge of the blade is positively correlated with the vertical distance from the center of the convex hull to the midline of the blade.

[0029] In this solution, the distribution of the convex hull conforms to the distribution law of the pressure difference on the blade, which can reduce the pressure difference, improve the internal vortex, thereby reducing aerodynamic noise and improving user experience.

[0030] Preferably, the convex hulls are arranged along the length direction of the blade, from the center line of the blade to the end of the blade, and the distance between two adjacent convex hulls gradually increases.

[0031] In this solution, the pressure difference is large at the center line of the blade, and the closer to the two ends of the blade, the smaller the pressure difference. The distribution of the convex hull is set according to the distribution law of the pressure difference on the blade, which can effectively reduce the pressure difference at different positions of the blade, improve the internal vortex, thereby reducing aerodynamic noise and improving user experience.

[0032] Preferably, the position of the convex hull is described using a Cartesian coordinate system, wherein the x-axis is on the center line of the blade, the y-axis is on the leading edge of the blade, the intersection of the x-axis and the y-axis is the coordinate origin, and the position distribution of the convex hull satisfies the following formula:

[0033] xn=m+(n-1)D,yn=y1*Q^ ( n- 1 );

[0034] Among them, the coordinates of the initial convex hull center are (m, 0), the coordinates of the nth convex hull center are (xn, yn), n is a positive integer; the value range of m is 4mm-9mm; the range of y1 is 6mm-10mm; Q is the geometric coefficient, the value range is 1-1.5, excluding 1; D is the arithmetic coefficient, the value range is 0.4-1.2.

[0035] In this solution, the convex hull is distributed in a geometric progression in the y-axis direction and in an arithmetic progression in the x-axis direction. This arrangement conforms to the distribution law of the pressure difference on the blade and can effectively reduce the pressure difference of the blade.

[0036] Preferably, a smooth inclined surface is provided at one end of the convex hull close to the trailing edge of the blade, and an arc surface is provided at the top of the convex hull, and the inclined surface and the arc surface are smoothly transitioned.

[0037] In this solution, pressure is transmitted through the opening of the convex hull, and the airflow at the convex hull moves along the movement trajectory of the outer surface of the convex hull, so that the movement direction of the main airflow is not affected by the through hole, which can further reduce the pressure difference.

[0038] Preferably, a range hood comprises the fan as described above.

[0039] In this solution, the range hood using the above-mentioned fan can improve the performance of the range hood, reduce operating noise, and enhance the user experience and comfort.

[0040] The positive progress effect of the present invention is:

[0041] In this solution, the pressure distribution on the pressure and non-pressure surfaces of the blade is irregular. The maximum pressure difference on the blade occurs in the front half of the blade near the leading edge. The pressure is significantly higher at the center of the blade along its length, and the closer to the ends of the blade, the lower the pressure on the blade. In this solution, the through-holes penetrate the blade along its thickness. The pressure transmission through the through-holes can reduce the pressure difference between the pressure and non-pressure surfaces of the blade. The distribution of the holes is set according to the pressure difference distribution pattern on the blade, which can effectively reduce the pressure difference at different positions, improve internal vortex, thereby reducing aerodynamic noise and improving user experience. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] Figure 1 This is a pressure distribution cloud diagram of the flow passage inside a blade without through holes in the prior art;

[0043] Figure 2 This is a pressure distribution cloud diagram of a blade without through holes in the prior art;

[0044] Figure 3 This is a schematic structural diagram of a fan according to embodiment 1 of the present invention;

[0045] Figure 4 This is a schematic front view of the structure of the blade of Example 1 of the present invention;

[0046] Figure 5 for Figure 4 A partial enlarged view of part A;

[0047] Figure 6 This is a pressure distribution cloud diagram of the inner flow channel of the blade of Example 1 of the present invention;

[0048] Figure 7 This is a schematic front view of the structure of a blade according to Example 2 of the present invention;

[0049] Figure 8 Schematic diagram of the cross-sectional structure of a blade according to Example 2 of the present invention;

[0050] Figure 9 This is a schematic structural diagram of the axial side of the blade of Example 2 of the present invention.

[0051] Impeller 100

[0052] Inner ring 110

[0053] Blade 200

[0054] Through hole 210

[0055] Blade leading edge 220

[0056] First area 230

[0057] Second area 240

[0058] Blade trailing edge 250

[0059] Convex hull 260

[0060] Opening 270 DETAILED DESCRIPTION

[0061] The present invention is further described below by way of examples, but the present invention is not limited to the scope of the examples.

[0062] In order to reduce noise, the present invention analyzes the pressure distribution of the flow channel inside the blade in the prior art. The pressure distribution cloud diagram of the flow channel inside the blade is as follows: Figure 1 As shown, the outer curved surface of the blade is the non-pressure surface, and the inner curved surface of the blade is the pressure surface. There is an obvious pressure difference between the pressure surface and the non-pressure surface between the blades. The place where the pressure difference between the pressure surface and the non-pressure surface between the blades is the largest is in the front half near the leading edge of the blade.

[0063] In addition, Figure 2 As shown, the pressure difference between the blades also shows a pattern in which the pressure difference is significantly larger at the center of the blade in the longitudinal direction, and the closer to the two ends of the blade, the smaller the pressure difference of the blade.

[0064] Based on the above analysis, the present invention improves the blades, which can reduce the pressure difference of the blades, reduce noise, and improve user experience, and provides the following technical solutions.

[0065] Example 1

[0066] like Figure 3-Figure 5 As shown, in this embodiment, a fan is provided, including an impeller 100, a plurality of blades 200 arranged at intervals along the circumference of the impeller 100, a plurality of through holes 210 are opened on the blades 200, and the plurality of through holes 210 are arranged at intervals along the length direction L of the blades 200.

[0067] The blade 200 includes a blade leading edge 220 and a blade trailing edge 250 that are oppositely disposed along the width direction W. The blade leading edge 220 is disposed close to the inner ring 110 of the impeller.

[0068] The specific structure of the blade 200 is as follows Figure 4 As shown, the right side of the blade in the figure is the blade leading edge 220 arranged close to the inner ring 110 of the impeller, and correspondingly, the left side of the blade in the figure is the blade trailing edge 250.

[0069] The distance from the center of each through hole 210 to the leading edge 220 of the blade is less than half the width of the blade 200; and along the length direction L of the blade 200, for any first area 230 and second area 240 where a through hole 210 is provided, the first area 230 and the second area 240 are independent of each other and have no overlapping area, wherein the first area 230 is closer to the center line of the length direction L of the blade 200 relative to the second area 240, and the spacing between two adjacent through holes 210 located in the first area 230 is smaller than the spacing between two adjacent through holes 210 located in the second area 240.

[0070] The pressure transmission through the through hole 210 can reduce the pressure difference between the pressure surface and the non-pressure surface of the blade 200, and the distribution of the holes is set according to the pressure difference distribution law on the blade 200, which can effectively reduce the pressure difference at different positions and improve the internal vortex, thereby reducing aerodynamic noise and improving user experience.

[0071] In other embodiments, the distance from the center of the through hole 210 to the blade leading edge 220 may also be equal to half the width of the blade 200 .

[0072] In other embodiments, the first region 230 and the second region 240 may also have an overlapping area, and the overlapping area may include a through hole 210 .

[0073] In this embodiment, the orthographic projection of the blade 200 is a long rectangle, and the outer surface of the blade 200 along the width direction W is an arc.

[0074] In this embodiment, the vertical distance from the center of through-hole 210 to the blade leading edge 220 is positively correlated with the vertical distance from the center of through-hole 210 to the centerline of blade 200. The distribution of through-holes 210 conforms to the distribution pattern of the pressure difference across blade 200, which can reduce the pressure difference and improve internal vortex flow, thereby reducing aerodynamic noise and improving the user experience.

[0075] In this embodiment, the through holes 210 are arranged along the length L of the blade 200, with the spacing between two adjacent through holes 210 gradually increasing from the centerline of the blade 200 to the ends of the blade 200. The pressure differential is large at the centerline of the blade 200, and decreases toward the ends of the blade 200. The distribution of the through holes 210 is based on the distribution pattern of the pressure differential on the blade 200, effectively reducing the pressure differential at different locations on the blade 200, improving internal vortex flow, and thereby reducing aerodynamic noise and enhancing the user experience.

[0076] In this embodiment, the positions of the through holes 210 are described using a Cartesian coordinate system, where the x-axis is on the centerline of the blade 200, the y-axis is on the leading edge 220 of the blade, and the intersection of the x-axis and the y-axis is the coordinate origin. The position distribution of the through holes 210 satisfies the following formula:

[0077] xn=m+(n-1)D,yn=y1*Q^ (n-1) ;

[0078] Among them, the coordinates of the center of the initial through hole 210 are (m, 0), the initial through hole 210 is the 0th through hole 210, the coordinates of the center of the nth through hole 210 are (xn, yn), n is a positive integer, m is 4 mm, y1 is 6 mm, Q is the geometric coefficient, which is 1.5, and D is the arithmetic coefficient, which is 0.4.

[0079] In this solution, the through holes 210 are distributed in a geometric progression in the Y-axis direction and in an arithmetic progression in the X-axis direction. This arrangement conforms to the distribution law of the pressure difference on the blade 200 and can effectively reduce the pressure difference of the blade 200.

[0080] In other embodiments, the value of m may be between 4 mm and 9 mm; the value of y1 may be between 6 mm and 10 mm; the value of Q may be between 1 and 1.5, excluding 1; and the value of D may be between 0.4 and 1.2.

[0081] In this embodiment, the through holes 210 are symmetrically distributed along the center line of the length direction L of the blade 200. The symmetrical distribution of the through holes 210 along the center of the blade 200 can adapt to the distribution of the pressure difference of the blade 200, which is conducive to reducing the pressure difference of the blade 200.

[0082] In other embodiments, the through holes 210 may not be distributed symmetrically along the center of the length direction L of the blade 200 .

[0083] In this embodiment, along the length L of the blade 200, the distance between the centers of two adjacent through holes 210 is between 1 / 20L and 1 / 8L, where L is the length of the blade 200. The spacing between adjacent through holes 210 is limited so that the through holes 210 can both reduce the pressure difference and reduce noise while not affecting the strength of the blade 200. If the spacing is too small, the through holes 210 will be too densely distributed, affecting the strength of the blade 200. If the spacing is too large, it will not be conducive to reducing noise.

[0084] like Figure 5 As shown, in this embodiment, the diameter B of the through hole 210 is 1.5 mm.

[0085] In other embodiments, the diameter B of the through hole 210 may also be between 1.5 mm and 3 mm.

[0086] In this solution, the diameter B of the through hole 210 is limited to between 1.5 mm and 3 mm, which effectively reduces the pressure difference and reduces noise without affecting the strength of the blade 200 body.

[0087] In this embodiment, the through hole 210 is circular in shape.

[0088] In other embodiments, the through hole 210 may also be elliptical or other smooth shapes.

[0089] In this embodiment, the inner flow channel of the fan is simulated, and the pressure distribution cloud of the inner flow channel of the blade is as follows: Figure 6 As shown, it can be seen that the pressure difference between the pressure surface and the non-pressure surface of the blade 200 is significantly improved.

[0090] In this embodiment, a range hood is also provided, comprising the above-mentioned fan.

[0091] In this solution, the range hood using the above-mentioned fan can improve the performance of the range hood, reduce operating noise, and enhance the user experience and comfort.

[0092] Example 2

[0093] like Figure 7-Figure 9 As shown, the structure of this embodiment is basically the same as that of embodiment 1, except that: in this embodiment, the blade 200 also includes a plurality of convex humps 260, a through hole 210 is arranged at the bottom of the convex humps 260, an opening 270 is provided on the side of the convex humps 260 close to the leading edge 220 of the blade, and the opening 270 is connected to the through hole 210, and the plurality of convex humps 260 are arranged at intervals along the length direction L of the blade 200.

[0094] Each through hole 210 penetrates the blade 200 along the thickness direction T of the blade 200 . The through hole 210 penetrates the blade 200 along the thickness direction T of the blade 200 , which is beneficial for transmitting the pressure on the blade 200 and reducing the pressure difference.

[0095] In other embodiments, the through holes 210 may also be arranged to have a certain angle with the thickness direction T.

[0096] The distance from the center of each convex bulge 260 to the blade leading edge 220 is less than half the width of the blade 200; and along the length direction L of the blade 200, for any first area 230 and second area 240 provided with a convex bulge 260, wherein the first area 230 is closer to the midline of the length direction L of the blade 200 relative to the second area 240, the spacing between two adjacent convex bulges 260 located in the first area 230 is less than the spacing between two adjacent convex bulges 260 located in the second area 240, wherein the spacing between two adjacent convex bulges 260 refers to the spacing between the centers of two adjacent convex bulges 260.

[0097] In this solution, the convex 260 is set according to the distribution law of the pressure difference on the blade 200, and the through hole 210 is set at the bottom of the convex 260, which can prevent the airflow from flowing back in the blade 200 and further reduce the pressure difference of the blade 200.

[0098] In other embodiments, the distance from the center of the convex hull 260 to the blade leading edge 220 may also be equal to half the width of the blade 200 .

[0099] In this embodiment, the outer periphery of the through hole 210 is located within the orthographic projection of the convex hull 260 on the upper surface of the blade 200. In this solution, it is possible to ensure that the through hole 210 can effectively transmit pressure.

[0100] In this embodiment, the vertical distance from the center of convex hump 260 to the blade leading edge 220 is positively correlated with the vertical distance from the center of convex hump 260 to the centerline of blade 200. The distribution of convex hump 260 conforms to the distribution pattern of the pressure difference on blade 200, which can reduce the pressure difference and improve internal vortex flow, thereby reducing aerodynamic noise and improving user experience.

[0101] In this embodiment, the distance between two adjacent convex humps 260 gradually increases along the length direction L of the blade 200 from the center line of the blade 200 to the end of the blade 200, wherein the distance between adjacent convex humps 260 refers to the distance between the centers of the convex humps 260.

[0102] In this solution, the pressure difference at the center line of the blade 200 is large, and the closer to the two ends of the blade 200, the smaller the pressure difference. The distribution of the convex hull 260 is set according to the distribution law of the pressure difference on the blade 200, which can effectively reduce the pressure difference at different positions of the blade 200, improve the internal vortex, thereby reducing aerodynamic noise and improving user experience.

[0103] In this embodiment, the position of the convex hull 260 is described using a Cartesian coordinate system, where the x-axis is on the centerline of the blade 200, the y-axis is on the leading edge 220 of the blade, and the intersection of the x-axis and the y-axis is the coordinate origin. The position distribution of the convex hull 260 satisfies the following formula:

[0104] xn=m+(n-1)D,yn=y1*Q^ (n-1) ;

[0105] The coordinates of the center of the initial convex hull 260 are (m, 0), the initial through hole 210 is the 0th through hole 210, the coordinates of the center of the nth through hole 210 are (xn, yn), n is a positive integer, m is 4 mm, y1 is 6 mm, Q is the geometric coefficient, which is 1.5, and D is the arithmetic coefficient, which is 0.4.

[0106] In this solution, the convex hull 260 is distributed in a geometric progression in the y-axis direction and in an arithmetic progression in the x-axis direction. This arrangement conforms to the distribution law of the pressure difference on the blade 200 and can effectively reduce the pressure difference of the blade 200.

[0107] In other embodiments, the value of m may be between 4 mm and 9 mm; the value of y1 may be between 6 mm and 10 mm; the value of Q may be between 1 and 1.5, excluding 1; and the value of D may be between 0.4 and 1.2.

[0108] In this embodiment, a smooth bevel is provided on one end of the convex hump 260 near the blade trailing edge 250, and a circular arc is provided on the top of the convex hump 260, with a smooth transition between the bevel and the circular arc. Pressure is transmitted through the opening 270 of the convex hump 260, and the airflow at the convex hump 260 follows the trajectory of the outer surface of the convex hump 260. This ensures that the direction of the main airflow is not affected by the through hole 210, further reducing the pressure difference.

[0109] In other embodiments, the outer surface of the convex hull 260 may also be streamlined as needed to reduce wind resistance when the blade rotates.

[0110] Although specific embodiments of the present invention have been described above, those skilled in the art will appreciate that these are merely illustrative and that the scope of the present invention is defined by the appended claims. Those skilled in the art may make various changes or modifications to these embodiments without departing from the principles and essence of the present invention, and such changes and modifications are intended to fall within the scope of the present invention.

Claims

1. A fan comprising an impeller and a plurality of blades spaced apart along the circumference of the impeller, characterized in that: The blade is provided with a plurality of through holes, each of the through holes passes through the blade along the thickness direction of the blade, and the plurality of through holes are spaced apart along the length direction of the blade; The blade includes a leading edge and a trailing edge that are oppositely arranged along the width direction, and the leading edge of the blade is arranged close to the inner ring of the impeller; The distance from the center of each through hole to the leading edge of the blade is less than or equal to half the width of the blade; and along the length direction of the blade, for any first area and second area where the through holes are provided, the first area is closer to the center line of the length direction of the blade relative to the second area, and the spacing between two adjacent through holes in the first area is less than the spacing between two adjacent through holes in the second area.

2. The fan according to claim 1, characterized in that The vertical distance from the center of the through hole to the leading edge of the blade is positively correlated with the vertical distance from the center of the through hole to the center line of the blade.

3. The fan according to claim 1, wherein: The through holes are arranged along the length direction of the blade, from the center line of the blade to the end of the blade, and the distance between two adjacent through holes gradually increases.

4. The fan according to claim 1, wherein: The positions of the through holes are described using a Cartesian coordinate system, wherein the x-axis is on the center line of the blade, the y-axis is on the leading edge of the blade, and the intersection of the x-axis and the y-axis is the coordinate origin. The position distribution of the through holes satisfies the following formula: x n =m+(n-1)D,y n =y1*Q (n-1) ; Among them, the coordinates of the initial through hole center are (m, 0), the coordinates of the nth through hole center are (xn, yn), n is a positive integer; the value range of m is 4mm-9mm; the range of y1 is 6mm-10mm; Q is the geometric coefficient, the value range is 1-1.5, excluding 1; D is the arithmetic coefficient, the value range is 0.4-1.

2.

5. The fan according to claim 4, characterized in that The through holes are symmetrically distributed along the midline of the length direction of the blade.

6. The fan according to claim 1, characterized in that Along the length direction of the blade, the distance between the centers of two adjacent through holes is between 1 / 20L and 1 / 8L, where L is the length of the blade.

7. The fan according to claim 1, characterized in that The diameter of the through hole is 1.5 mm to 3 mm.

8. The fan according to claim 1, wherein: The blade further includes a plurality of convex hulls, the through hole is provided at the bottom of the convex hull, an opening is provided on a side of the convex hull close to the leading edge of the blade, and the opening is connected to the through hole, and the plurality of convex hulls are spaced apart along the length direction of the blade; The distance from the center of each convex hull to the leading edge of the blade is less than or equal to half the width of the blade; and along the length direction of the blade, for any first area and second area where the convex hull is provided, wherein the first area is closer to the midline of the length direction of the blade relative to the second area, the spacing between two adjacent convex hulls in the first area is smaller than the spacing between two adjacent convex hulls in the second area.

9. The fan according to claim 8, characterized in that The outer periphery of the through hole is located within the orthographic projection of the convex hull on the upper surface of the blade.

10. The fan according to claim 8, characterized in that The vertical distance from the center of the convex hull to the leading edge of the blade is positively correlated with the vertical distance from the center of the convex hull to the midline of the blade.

11. The fan according to claim 8, characterized in that The convex hulls are arranged along the length direction of the blade, from the center line of the blade to the end of the blade, and the distance between two adjacent convex hulls gradually increases.

12. The fan according to claim 8, characterized in that The position of the convex hull is described using a Cartesian coordinate system, where the x-axis is on the center line of the blade, the y-axis is on the leading edge of the blade, and the intersection of the x-axis and the y-axis is the coordinate origin. The position distribution of the convex hull satisfies the following formula: xn=m+(n-1)D,in=y1*Q^ (n-1) ; Among them, the coordinates of the initial convex hull center are (m, 0), the coordinates of the nth convex hull center are (xn, yn), n is a positive integer; the value range of m is 4mm-9mm; the range of y1 is 6mm-10mm; Q is the geometric coefficient, the value range is 1-1.5, excluding 1; D is the arithmetic coefficient, the value range is 0.4-1.

2.

13. The fan according to claim 8, wherein The convex hull is provided with a smooth inclined surface at one end close to the trailing edge of the blade, and the top of the convex hull is provided with an arc surface, and the inclined surface and the arc surface are smoothly transitioned.

14. A range hood, characterized in that: It comprises the fan according to any one of claims 1-13.

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