CN116398470A

CN116398470A - Outer rotor axial flow impeller

Info

Publication number: CN116398470A
Application number: CN202310440546.8A
Authority: CN
Inventors: 裘霖富; 刘伟; 袁鹏程; 张职锋; 竺春辉; 陈钱
Original assignee: Zhejiang Kemao Industrial Co ltd
Current assignee: Zhejiang Kemao Industrial Co ltd
Priority date: 2023-04-23
Filing date: 2023-04-23
Publication date: 2023-07-07

Abstract

The invention discloses an outer rotor axial flow impeller, which relates to the technical field of fan blade overspeed tests and comprises a fan blade and a hub, wherein the fan blade and the hub are matched with an outer rotor motor, the fan blade is arranged on the hub, a cavity is formed in the hub, a plurality of stand columns are distributed on the inner circumference of the hub, a fan blade curved surface is arranged on the fan blade, a saw-tooth-shaped structure is arranged on the tail edge of the fan blade, and a thickened flap structure similar to a blade shape is arranged on the fan blade. The device improves the air quantity of the working point and reduces the noise by optimizing the curved surface of the fan blade; by thinning the front edge of the blade, the pneumatic noise is reduced; the weight of the product is reduced by arranging the hollow structure of the hub; by arranging the thickened flap structure, the energy efficiency can be improved, the noise of the fan can be reduced, and the strength of the fan blade can be enhanced; the balance block clamping groove on the back of the blade is arranged, so that the balance block is prevented from loosening and falling, the smooth smoothness of the windward side of the blade is not affected, and the pneumatic noise is reduced; noise can be reduced by providing blade trailing edge serrations.

Description

Outer rotor axial flow impeller

Technical Field

The invention relates to the technical field of axial flow impellers, in particular to an outer rotor axial flow impeller.

Background

The fan impeller is a core component of the fan, and the quality of the impeller design is directly related to the performance and efficiency of the fan. With the development of the fan industry, the requirements on the performance of the fan are more and more, and the requirements on the efficiency of the fan are more and more. The curved surface of the fan blade is an extremely critical step in the design of the fan, the fan blade is used for being matched with an outer rotor motor to form the fan, and as an axial flow fan structure, the curved surface of the fan blade determines various performances of the fan, such as: noise, air volume, vibration, etc.

In the prior art, in the existing outer rotor axial flow impeller, the contact area between the side surface of the front edge of the fan blade and air is larger, and the friction loss between the fan blade and the air is larger, so that the energy conversion rate of the fan blade is reduced, and the energy efficiency is indirectly reduced;

in the existing outer rotor axial flow impeller, the relative rotation or loosening phenomenon is easy to occur between the outer rotor axial flow impeller and the outer rotor motor;

in the existing outer rotor axial flow impeller, the fan blade is easy to deform or break in the long-time use process. On the other hand, in the rotating process of the fan blade, a pressure difference is formed between the windward side and the leeward side, a gap exists between the fan blade and the guide ring, and due to the existence of the pressure difference, air flow can be generated in the gap, so that loss is generated, and the efficiency is reduced;

in the existing outer rotor axial flow impeller, a motor is in interference fit with the fan blades, deformation is easy to occur, the roundness of the hub of the fan blades is changed, each fan blade generates deviation, and the performance and the service life of the fan are reduced.

Disclosure of Invention

In order to solve the problems in the prior art, the invention provides an outer rotor axial flow impeller. The device improves the air quantity of the working point and reduces the noise by optimizing the curved surface of the fan blade; by thinning the front edge of the blade, the pneumatic noise is reduced; the weight of the product is reduced by arranging the hollow structure of the hub; by arranging the thickened flap structure, the energy efficiency can be improved, the noise of the fan can be reduced, and the strength of the fan blade can be enhanced; the balance block clamping groove on the back of the blade is arranged, so that the balance block is prevented from loosening and falling, the smooth smoothness of the windward side of the blade is not affected, and the pneumatic noise is reduced; noise can be reduced by providing blade trailing edge serrations.

In order to achieve the above purpose, the present invention is realized by the following technical scheme:

the utility model provides an external rotor axial flow impeller, includes be used for with external rotor motor complex fan blade, wheel hub, the fan blade is located on the wheel hub, be equipped with the cavity in the wheel hub, the circumference distributes in the wheel hub has a plurality of stands, be equipped with the fan blade curved surface on the fan blade, the fan blade trailing edge is equipped with the cockscomb structure, be equipped with on the fan blade and be the thickening flap structure of type cutting edge form.

In this embodiment, the outer side of the fan blade is turned down and thickened, and the width of the thickened position decreases from the trailing edge of the fan blade to the leading edge of the fan blade until the leading edge of the fan blade is thinned.

In this embodiment, a plurality of blade shaping curves are provided on the front edge of the blade.

In this embodiment, the root of the fan blade is provided with a zigzag reinforcing structure.

In this embodiment, the cavity is circular, and is used for cooperation fixed mounting steel ring.

In this embodiment, the saw tooth structure includes a plurality of saw teeth.

In this embodiment, the plurality of serrations are uniform in shape.

In this embodiment, the cross section of the meandering reinforcement structure is in a groove shape.

In this embodiment, the fan blade is provided with a balancing block clamping groove, and the balancing block clamping groove is used for placing a balancing block.

In this embodiment, the fan blade is made of plastic.

Compared with the prior art, the invention has the advantages that:

the device forms a structure similar to a blade by thinning the front edge of the fan blade, the front edge of the fan blade is thinner, the friction loss with air is greatly reduced, the energy conversion rate of the fan blade is improved, and the energy efficiency is indirectly improved. The front edge of the fan blade is thinned, so that the collision area between the side face of the front edge of the fan blade and air can be directly reduced, the area of direct impact of the fan blade and the air flow direction in the normal direction is reduced, the impact force of the fan blade can be effectively reduced, and the service life of the device is prolonged.

The stand columns are distributed on the inner circumference of the fan blade hub, the stand columns are used for reducing the shrinkage deformation problem caused by too large thickness change of the rubber position at the hub position in the injection molding process of a product, the hub is prevented from being out of round, the service life and the attractiveness of the product are improved, meanwhile, the stand columns can be used for fixedly mounting the steel ring, the binding force of the outer rotor axial flow fan blade and the outer rotor motor is improved, the relative rotation or loosening phenomenon between the outer rotor axial flow fan blade and the outer rotor motor is avoided, and the reliability of the device is improved.

The device ensures the smooth surface of the windward side of the fan blade and reduces the pneumatic noise of the windward side of the fan blade by designing the balance block clamping grooves on the back of the fan blade, namely on the leeward side of the fan blade.

The device improves the strength of the outer side of the fan blade by downwards flanging and thickening the outer side of the fan blade, and greatly reduces the deformation or fracture of the fan blade in the long-time use process; meanwhile, in the rotating process of the fan blade, a pressure difference is formed between the windward side and the leeward side, so that a gap exists between the fan blade and the guide ring, the outer side of the fan blade is bent downwards and thickened, and the loss caused by air flow generated in the gap can be reduced. The width of the thickening position is gradually decreased from the tail edge to the front edge until the front edge of the fan blade is thinned, and the width of the thickening position is gradually decreased from the tail edge of the fan blade to the transition section of the front edge, so that the damage caused by the over-sharp front end is avoided.

The device distributes a plurality of saw-tooth structures with completely consistent sizes on the tail edge of the fan blade, ensures that the shapes of the saw-tooth structures are consistent through function modeling, and cannot deform and deviate due to nonlinear distribution tracks. The sawtooth-shaped structure extends from the middle point of the tail edge curve of the fan blade to a thickening position, so that stress concentration caused by the fact that the sawtooth-shaped structure is too close to the outer edge of the fan blade is avoided, and the strength and the service life of the fan blade are guaranteed.

The device optimizes the performance through the cambered surface of the fan blade, improves the air quantity of the working point, and remarkably reduces the noise. The performance of the curved surface, the rear edge, the front edge and the root of the fan blade are optimized by combining CFD simulation analysis and actual test, so that the pneumatic noise of the windward side of the fan blade is reduced, the strength of the fan blade is ensured, and the performance and the service life of the fan are improved.

This device can prevent that the fan blade from warp through carrying out the cavity design at wheel hub: the impeller is fixed with a steel part at the position, and the steel part is connected with a motor to realize rotation. The specific implementation mode is as follows: on the plastic mould, the steel part is positioned and fixed at the design position in advance, then injection molding is carried out, and the steel part is fixed on the hub after molding. The motor is in interference fit with the fan blades, deformation is necessarily generated, the roundness of the hub of the fan blades is changed, each fan blade generates deviation, and the performance and the service life of the fan are reduced. The cavity structure can effectively reduce the influence of deformation on the fan, the deformation of the steel part can squeeze the cavity, the cavity is deformed, the deformation degree of the plastic impeller is greatly reduced, and the influence on the subsequent processing is small.

The cavity structure assists the motor in dissipating heat: the existence of the cavity can generate air flow to quicken the heat dissipation of the rotor part of the motor.

The cavity can guarantee intensity when reducing fan blade weight: on the one hand, the weight of the fan blade can be reduced at the position of the cavity, and the connection strength of the hub and the motor is ensured. On the other hand, the position is realized on the die through the insert, and the diameter of the position can be increased by replacing the solid insert, so that the position can accommodate a larger motor, and the customer population is enlarged.

The plastic hub is prevented from being torn in the assembly process by the full fillets on two sides of the cavity: because the motor and the steel on the hub are in interference fit, a small amount of deformation can be generated during assembly. If a solid hub is used, the service life of the product can be influenced by a trace of large deformation; when the deformation position is changed into the cavity, the deformation position is moved to the cavity position, and the deformation degree is reduced. The full fillets on the two sides of the cavity move the deformation to the center of the cavity again, so that the connection position is prevented from being damaged, and the strength and the service life of the hub are ensured.

Circular cavity can cooperate the installation steel ring: the circular cavity is used for being matched with a fixed mounting steel ring, the fixing directions of the mounting steel ring are different, and the mounting directions of the fan blades and the motor are also different, namely, one set of die can replace the die insert, and meanwhile, two different fan blades for induced air and air blast are produced, so that the manufacturing cost of the die is reduced.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings that are required in the embodiments or the description of the prior art will be briefly described, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and other drawings may be obtained according to the structures shown in these drawings without inventive effort for a person skilled in the art.

FIG. 1 is a schematic view of the overall structure of an outer rotor axial flow impeller according to an embodiment of the present invention;

fig. 2 is a schematic structural diagram of a shaping curve of a fan blade formed by intersecting a curved surface of the fan blade with a circular curved surface of ∅ in an outer rotor axial flow impeller according to an embodiment of the present invention;

fig. 3 is a schematic structural diagram of a shaping curve of a fan blade formed by intersecting a curved surface of the fan blade with a circular curved surface of ∅ in an outer rotor axial flow impeller according to an embodiment of the present invention;

fig. 4 is a schematic structural diagram of a shaping curve of a fan blade formed by intersecting a curved surface of the fan blade with a circular curved surface ∅ in an outer rotor axial flow impeller according to an embodiment of the present invention;

fig. 5 is a schematic structural diagram of a shaping curve of a fan blade formed by intersecting a curved surface of the fan blade with a circular curved surface of ∅ in an outer rotor axial flow impeller according to an embodiment of the present invention;

fig. 6 is a schematic structural diagram of a shaping curve of a fan blade formed by intersecting a curved surface of the fan blade with a circular curved surface of ∅ in an outer rotor axial flow impeller according to an embodiment of the present invention;

fig. 7 is a schematic structural diagram of a shaping curve of a fan blade formed by intersecting a curved surface of the fan blade with a circular curved surface of ∅ in an outer rotor axial flow impeller according to an embodiment of the present invention;

fig. 8 is a schematic structural diagram of 6 shaping curves of fan blades formed by intersecting curved surfaces of fan blades and circular curved surfaces of ∅, 125, 150, 200, 250, 300 and 350 in an outer rotor axial flow impeller according to an embodiment of the present invention;

fig. 9 is a schematic structural view of a meandering reinforcing structure for a blade root of an outer rotor axial flow impeller according to an embodiment of the present invention.

In the figure: 1. the wind turbine blade comprises wind blades 11, wind blade curved surfaces 12, saw-tooth structures 121, saw teeth 13, thickened flap structures 131, wind blade modeling curves 14, balancing block clamping grooves 15, a bending reinforcing structure 2, hubs 21, cavities 22 and upright posts.

Detailed Description

Reference will now be made in detail to embodiments of the present invention, examples of which are illustrated in the accompanying drawings. The embodiments described below by referring to the drawings are illustrative and intended to explain the present invention and should not be construed as limiting the invention.

In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. indicate orientations or positional relationships based on the drawings are merely for convenience in describing the present invention and simplifying the description, and do not indicate or imply that the apparatus or elements referred to must have a specific orientation, be configured and operated in a specific orientation, and thus should not be construed as limiting the present invention.

Furthermore, the terms "first," "second," and the like, are used for descriptive purposes only and are not to be construed as indicating or implying a relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defining "a first" or "a second" may explicitly or implicitly include at least one such feature. In the description of the present invention, the meaning of "plurality" means at least two, for example, two, three, etc., unless specifically defined otherwise.

In the present invention, unless explicitly specified and limited otherwise, the terms "mounted," "connected," "secured," and the like are to be construed broadly, and may be, for example, fixedly connected, detachably connected, or integrally formed; may be mechanically connected, may be electrically connected or may be in communication with each other; either directly or indirectly, through intermediaries, or both, may be in communication with each other or in interaction with each other, unless expressly defined otherwise. The specific meaning of the above terms in the present invention can be understood by those of ordinary skill in the art according to the specific circumstances.

Referring to fig. 1-9, an embodiment of an outer rotor axial flow impeller according to the present invention includes a fan blade 1 for cooperating with an outer rotor motor, and a hub 2, where the fan blade 1 is disposed on the hub 2, and a cavity 21 is disposed in the hub 2, where the cavity 21 can prevent deformation of the fan blade 1: the impeller 1 fixes a steel part at the position, and the steel part is connected with a motor to realize rotation. The specific implementation mode is as follows: on the plastic mould, the steel part is positioned and fixed at the design position in advance, then injection molding is carried out, and the steel part is fixed on the hub 2 after molding. The motor is in interference fit with the fan blade 1, and deformation is necessarily generated, so that roundness of the hub 2 is changed, each blade generates deviation, and performance and service life of the fan are reduced. The cavity 21 structure can effectively reduce the influence of deformation on the fan, the deformation of the steel part can squeeze the cavity 21, the cavity 21 deforms, the deformation degree of the plastic impeller is greatly reduced, and the influence on the subsequent processing is small.

The structure of the cavity 21 assists the motor in dissipating heat: the presence of this cavity 21 enables an air flow to be generated, accelerating the heat dissipation of the rotor portion of the motor.

The cavity 21 can reduce the weight of the blade while ensuring strength: on the one hand, the position of the cavity 21 can reduce the weight of the fan blade and ensure the connection strength of the hub 2 and the motor. On the other hand, the position is realized on the die through the insert, and the diameter of the position can be increased by replacing the solid insert, so that the motor can be accommodated in a larger size, and the application range is enlarged.

The full fillets on the two sides of the cavity 21 prevent the plastic hub 2 from being torn in the assembly process: because the motor and the steel on the hub 2 are in interference fit, a small amount of deformation can be generated during assembly. If a solid hub 2 is used, the service life of the product can be influenced by a small amount of large deformation; when the deformation position is changed to the cavity 21, the deformation degree becomes smaller by moving the deformation position to the cavity 21 position. The full fillets on the two sides of the cavity 21 move the deformation to the center of the cavity 21 again, so that the connection position is prevented from being damaged, and the strength and the service life of the hub 2 are ensured.

The cavity 21 is circular and can be matched with an installation steel ring: the circular cavity 21 is used for matching with a fixed installation steel ring, the fixing directions of the installation steel ring are different, the installation directions of the fan blades 1 and the motor are also different, namely, one set of die can replace the die insert, and meanwhile, two different fan blades 1 for induced air and air blast are produced, so that the manufacturing cost of the die is reduced.

At least two upright posts 22 are distributed on the inner circumference of the wheel hub 2, and the upright posts 22 have the technical effect of reducing the shrinkage deformation problem caused by too large thickness change of the glue position at the position of the wheel hub 2 in the injection molding process of a product, avoiding the out-of-round wheel of the wheel hub 2 and improving the service life and the aesthetic degree of the product; the physical function is to fixedly install the steel ring, improve the binding force of the fan blade 1 and the outer rotor motor, and avoid the relative rotation or looseness phenomenon between the fan blade 1 and the outer rotor motor. The upright posts 22 may be uniformly distributed or unevenly distributed, and under the condition of uneven distribution, the included angle between the upright posts 22 is extremely no greater than 3 degrees, i.e. the maximum included angle-the minimum included angle is less than or equal to 3 degrees. The number of the upright posts 22 depends on the number of the fan blades, for example, 5 fan blades, the number k of the upright posts 22 is preferably k= 5*n, and if the number of the fan blades is x, the number k of the upright posts 22 is preferably k=x×n (n is an integer greater than 0);

the fan blade 1 is provided with a fan blade curved surface 11, and the tail edge of the fan blade 1 is distributed with a sawtooth-shaped structure 12; the performance of the cambered surface of the blade is optimized by combining CFD simulation analysis and actual test, and the blade 1 is provided with a thickened flap structure 13 similar to a blade. The front edge of the fan blade 1 is thinner, the thickness of the thinnest position is smaller than 0.5mm, a structure similar to a blade is formed, friction loss with air is greatly reduced, the energy conversion rate of the fan blade 1 is improved, and the energy efficiency is indirectly improved. The reduction of the position can directly reduce the collision area between the side surface of the front edge of the fan blade 1 and air, effectively reduce the impact force received and prolong the service life. The thinnest position of the front edge of the fan blade 1 and the fan blade 1 adopt smooth transition. The section of the thinnest position and the transition position can be triangle, circle, ellipse, trapezoid, or the shape can be changed as mentioned above, such as sharp corner rounding, straight edge is replaced by curve, etc.

In this embodiment, the outer side of the fan blade 1 is turned down and thickened, and the width of the thickened position decreases from the tail edge of the fan blade 1 to the front edge 13 of the fan blade until the front edge 13 of the fan blade is thinned. The thickening of the outer side of the fan blade 1 is to improve the strength of the outer side of the fan blade on one hand, and avoid the deformation (mainly the maximum height of the fan blade) or fracture (mainly the blade tip position) of the fan blade 1 in the long-time use process. On the other hand, because the fan blade 1 can form pressure difference between the windward side and the leeward side in the rotating process, and a gap exists between the fan blade and the guide ring, because of the existence of the pressure difference, air flow can be generated in the gap, loss is generated, the outer side of the fan blade is bent downwards and thickened, the loss can be reduced to a certain extent, and the efficiency is improved. The width of the thickened positions is gradually reduced from the tail edge to the front edge of the blade, so that the blade is attractive in appearance and damage caused by the fact that the front end is too sharp is avoided.

In this embodiment, six blade shaping curves 131 are provided on the blade leading edge 13.

In this embodiment, the root of the fan blade 1 is provided with a meandering reinforcement structure 15. As shown in fig. 9, the wind blade root zigzag reinforcement structure 15 has a total length of a, an elevation angle of α degrees, a cross section of the reinforcement structure is shown as a groove shape, a in the groove has a length of a = (1/4-1/3) ×a, the elevation angle of β degrees, β = γ - (0-5), and a groove depth of B = (1/3-7/18) ×a.

In this embodiment, the cavity 21 is circular and is used for matching and fixedly installing a steel ring.

In this embodiment, the serrated structure 12 includes a plurality of serrations 121. The characteristic is modeled by a function, so that the shape of the serrated structure 12 is consistent, and deformation and deviation cannot be generated due to nonlinear distribution tracks;

in this embodiment, at least two serrations 121 are identical in shape. The saw teeth 121 extend from the midpoint of the blade trailing edge curve to a thickened position in order to avoid stress concentrations arising from the saw teeth 121 being too close to the outer edge of the blade, ensuring the strength and life of the blade.

In this embodiment, the cross section of the meandering reinforcement structure 15 is in a groove shape.

In this embodiment, the fan blade 1 is provided with a balancing block clamping groove 14, and the balancing block clamping groove 14 is used for placing a balancing block. The balancing block clamping grooves 14 are distributed on the back (lee surface) of the fan blade 1, so that the smoothness of the curved surface of the windward surface of the fan blade 1 is ensured. The design is for attractive appearance on one hand and for reducing aerodynamic noise of the windward side of the fan blade 1 on the other hand.

In this embodiment, the fan blade 1 is made of plastic.

In the specific implementation, the fan blade 1 is used for being matched with an outer rotor motor to form a fan, and is of an axial flow fan structure. The fan blade is fixed with the motor rotor shell through the flange, the flange is directly fixed inside the fan blade 1 in the injection molding process, the flange is placed on the plastic mold positioning structure of the fan blade 1, the fan blade is directly fixed in an injection molding way through a high Wen Jiaoti extruded by a screw rod of an injection molding machine, the fan blade is formed after cooling, the flange is sleeved on the outer rotor motor, the outer rotor motor is connected with a flange plate of the net cover, and the net cover is fixed on the panel to form a complete fan structure.

After the fan blade 1 is horizontally placed, the circular curved surfaces with the stretching diameters of 125, 150, 200, 250, 300 and 350 are respectively intersected with the fan blade curved surface 11 to form 6 fan blade modeling curves. An a plane with an angle of 15 degrees with the Y plane is established with an axis formed by intersecting the X, Y plane as a rotation center. The front view of the a plane (75 degrees from the Y plane) is taken as the viewing angle to see 6 modeling curves as follows.

As shown in fig. 2, the elevation angle of the straight line connecting the head and the tail of the modeling curve formed by intersecting the curved surface of the fan blade 1 and the circular curved surface of ∅ is 42 degrees.

As shown in fig. 3, the elevation angle of the straight line connecting the head and the tail of the modeling curve formed by intersecting the curved surface of the fan blade 1 and the circular curved surface of ∅ is 39 degrees.

As shown in fig. 4, the elevation angle of the straight line connecting the head and the tail of the modeling curve formed by intersecting the curved surface of the fan blade 1 and the circular curved surface of ∅ is 34 degrees.

As shown in fig. 5, the elevation angle of the straight line connecting the head and the tail of the modeling curve formed by intersecting the curved surface of the fan blade 1 and the circular curved surface of ∅ is 31 degrees.

As shown in fig. 6, the elevation angle of the straight line connecting the head and the tail of the modeling curve formed by intersecting the curved surface of the fan blade 1 and the circular curved surface of ∅ is 28 degrees.

As shown in fig. 7, the elevation angle of the straight line connecting the head and the tail of the modeling curve formed by intersecting the curved surface of the fan blade 1 and the circular curved surface of ∅ is 26 degrees.

As shown in FIG. 8, the lower left corners of the different shaping curves are sequentially hooked together to form the front edge of the blade, and the upper right corners of the different shaping curves are sequentially hooked together to form the rear edge of the blade.

The edge of the fan blade 1 is thickened to form a streamline boss structure with a front narrow and a rear wide, the boss is 1.75-3.5mm in height, namely the thickness= (0.5-1%) of D (D is the diameter of the fan blade), the front narrow and the rear wide, the boss is close to the side of the hub 2 and is in smooth transition with the back of the fan blade, and the width of the tail edge of the fan blade is 5-14mm (1.4-4% of the diameter D of the fan blade), namely the maximum width H= (1.4-4%) of the tail edge of the fan blade.

The fan blade hub 2 is symmetrical about the transverse tangential plane, and the total height s3, s3= (1-1.5%) of the fan blade hub 2 is equal to D. The distance s2, s 2= (1/4-1/3) s3 between the contact surface of the hub 2 and the flange and the opening of the hub 2, a plurality of boss fixing structures 23 are distributed in the hub 2, the boss heights h, h= (40% -50%) s2, blind holes with the diameter of 2mm and the depth h are formed in the middle of the boss structures, and buckling positions can be formed at the positions by matching with the blind holes with the flange, so that the flange is prevented from rotating relatively.

The technical features of the above-described embodiments may be arbitrarily combined, and all possible combinations of the technical features in the above-described embodiments are not described for brevity of description, however, as long as there is no contradiction between the combinations of the technical features, they should be considered as the scope of the description.

The above examples merely represent a few embodiments of the present application, which are described in more detail and are not to be construed as limiting the scope of the invention. It should be noted that it would be apparent to those skilled in the art that various modifications and improvements could be made without departing from the spirit of the present application, which would be within the scope of the present application. Accordingly, the scope of protection of the present application is to be determined by the claims appended hereto.

Claims

1. The utility model provides an external rotor axial flow impeller, its characterized in that, including being used for with external rotor motor complex fan blade (1), wheel hub (2), on wheel hub (2) are located to fan blade (1), be equipped with cavity (21) in wheel hub (2), the interior circumference distribution of wheel hub (2) has a plurality of stands (22), be equipped with fan blade curved surface (11) on fan blade (1), fan blade (1) trailing edge is equipped with serrated structure (12), be equipped with on fan blade (1) and be blade-like thickening flap structure (13).

2. The outer rotor axial flow impeller according to claim 1, wherein the thickened flap structure (13) is formed by flanging the outer side of the fan blade (1) downwards and thickening, and the width of the thickened position is gradually reduced from the tail edge of the fan blade (1) to the front edge of the fan blade (1) until the front edge of the fan blade (1) is thinned.

3. The outer rotor axial flow impeller according to claim 2, wherein a plurality of blade shaping curves (131) are arranged on the front edge of the blade (1).

4. The outer rotor axial flow impeller according to claim 1, characterized in that the root of the fan blade (1) is provided with a meandering reinforcement structure (15).

5. The outer rotor axial flow impeller according to claim 1, characterized in that the cavity (21) is circular for fitting a fixed mounting rim.

6. The outer rotor axial flow impeller of claim 5, wherein the serration structure (12) comprises a plurality of serrations (121).

7. The outer rotor axial flow impeller of claim 1, wherein the plurality of serrations (121) are uniform in shape.

8. The outer rotor axial flow impeller according to claim 4, characterized in that the cross section of the meandering reinforcement structure (15) is groove-like.

9. The outer rotor axial flow impeller according to claim 1, wherein the fan blade (1) is provided with a balancing block clamping groove (14), and the balancing block clamping groove (14) is used for placing a balancing block.

10. The outer rotor axial flow impeller according to claim 1, characterized in that the material of the fan blades (1) is plastic.