Fan structure

Abstract

The application discloses a fan structure, which comprises a fan blade and a heat dissipation piece. The fan blade comprises a cover and a plurality of blades, and the plurality of blades are connected to the outer circumferential side of the cover. The heat dissipation piece is at least partially located in the cavity of the cover, and the heat dissipation piece comprises an outer ring, an inner ring and a plurality of fins. The plurality of fins are connected to the outer ring and the inner ring, and at least part of the outer ring is embedded in the wall part of the cover. The application supports the cover of the fan blade by embedding at least part of the outer ring of the heat dissipation piece in the wall part of the cover, effectively improves the structural strength of the fan blade, and prevents the fan blade from being deformed during high-speed operation.

Description

TECHNICAL FIELD

[0001] The application relates to a fan structure and belongs to the technical field of heat dissipation fans. BACKGROUND

[0002] A fan assembly is an important component of a heat dissipation system of an automobile engine, and the fan assembly comprises fan blades, a casing, a permanent magnet, a stator winding and a motor. The fan blades comprise a plurality of fan blade bodies and a cover, the plurality of fan blade bodies are arranged in a circumferential direction around the cover, and the cover is fixedly connected to the casing. The fan blades are mostly made of plastic material, have large dimensions and thin wall thicknesses. When the fan assembly is in high-speed operation, the cover of the fan blades is subjected to large stress and is prone to deformation and imbalance, thereby affecting the NVH performance of the vehicle. SUMMARY

[0003] The application aims to provide a fan structure with high structural strength and low deformation.

[0004] To achieve the above-mentioned purpose, the application adopts the following technical scheme:

[0005] A fan structure comprises:

[0006] Fan blades, the fan blades comprising a cover and a plurality of blades, the plurality of blades being connected to an outer circumferential side of the cover; and

[0007] A heat dissipation member, the heat dissipation member being at least partially located in a cavity of the cover, the heat dissipation member comprising an outer ring, an inner ring and a plurality of fins, the plurality of fins being connected to the outer ring and the inner ring, and at least a portion of the outer ring being embedded in a wall portion of the cover.

[0008] As a further improved technical scheme of the application, the fan blades are made of plastic material, the heat dissipation member is made of metal material, and the fan blades and the heat dissipation member are integrally injection molded.

[0009] As a further improved technical scheme of the application, the cover is provided with a through hole in an area surrounded by the inner ring.

[0010] As a further improved technical scheme of the application, the fan structure comprises a driving assembly, the driving assembly comprising a driving member and a casing capable of being driven to rotate by the driving member,

[0011] The cover comprises a circumferential wall portion and a bottom wall portion connected to the circumferential wall portion, the casing is installed in a space surrounded by the inner ring and the bottom wall portion, and the casing is in interference fit with the inner ring.

[0012] The driving assembly further comprises a magnet, and the magnet is installed in the casing.

[0013] As a further improved technical scheme of the present application, the cover shell comprises a peripheral wall portion and a bottom wall portion connected with the peripheral wall portion, the peripheral wall portion comprises an outer peripheral surface and an inner peripheral surface, a plurality of the vanes are connected to the outer peripheral surface, the inner peripheral surface is located at the periphery of the cavity, and the outer ring is located between the outer peripheral surface and the inner peripheral surface.

[0014] As a further improved technical scheme of the present application, the outer ring, the outer peripheral surface and the inner peripheral surface are coaxially arranged.

[0015] As a further improved technical scheme of the present application, the cover shell further comprises a plurality of reinforcing ribs, and the plurality of reinforcing ribs are connected with the inner peripheral surface of the peripheral wall portion and the inner bottom surface of the bottom wall portion.

[0016] The plurality of reinforcing ribs correspond to the plurality of fins, and each reinforcing rib corresponds to a portion of the fin.

[0017] As a further improved technical scheme of the present application, the reinforcing rib comprises an outer end surface, the outer end surface is an arc-shaped surface recessed towards the bottom wall portion, any two adjacent reinforcing ribs are connected by a connecting portion, the inner ring is located in the cavity, and the plurality of connecting portions are arranged around the inner ring and connected with the wall surface of the inner ring facing the inner peripheral surface.

[0018] As a further improved technical scheme of the present application, the bottom wall portion is provided with a plurality of heat dissipation holes, the plurality of heat dissipation holes are arranged in a circle, and the bottom wall portion is provided with at least one heat dissipation hole in the area surrounded by the adjacent two reinforcing ribs.

[0019] As a further improved technical scheme of the present application, the fan blade comprises a support ring, and the support ring is connected with the plurality of vanes between the support ring and the cover shell.

[0020] Compared with the prior art, the present application has the following beneficial effects: by arranging the heat dissipation member, the heat dissipation member comprises an outer ring, an inner ring and a plurality of fins, at least part of the outer ring is embedded in the wall portion of the cover shell to support the cover shell of the fan blade, effectively improving the structural strength of the fan blade, and the plurality of fins of the heat dissipation member disperses the stress of the cover shell to the inner ring, so that the fan blade is not easy to deform during high-speed operation, which is beneficial to the balanced operation of the fan blade and optimizes the NVH performance of the whole vehicle; in addition, the heat dissipation member can improve the heat dissipation effect at the fan blade, effectively reduce the temperature, thereby reducing the demagnetization of the magnet caused by the temperature and reducing the aging of the fan blade caused by high temperature, improving the service life and reliability. BRIEF DESCRIPTION OF DRAWINGS

[0021] Figure 1 is a three-dimensional schematic view of a fan structure of the present application;

[0022] Figure 2 is an exploded view of Figure 1 ;

[0023] Figure 3 is Figure 1 another perspective view;

[0024] Figure 4 is Figure 3 an exploded view;

[0025] Figure 5 is Figure 1 a sectional perspective view;

[0026] Figure 6 is Figure 5 an enlarged view of area A in FIG.

[0027] Figure 7 is Figure 1 a perspective view of the fan blade and the heat dissipating member in FIG.

[0028] Figure 8 is Figure 7 an enlarged view of area B in FIG.

[0029] Figure 9 is a perspective view of the fan blade in FIG.

[0030] Figure 10 Figure 9 is an enlarged view of area C in FIG. DETAILED DESCRIPTION

[0031] The exemplary embodiments of the present application will be described in detail below with reference to the attached drawings. If there are several embodiments, the features of the embodiments can be combined with each other when there is no conflict. When the description refers to the drawings, the same numbers on different drawings represent the same or similar elements unless otherwise specified. The description in the following exemplary embodiments does not represent all embodiments consistent with the present application; rather, they are merely examples of devices, products and / or methods consistent with some aspects of the present application as recited in the claims of the present application.

[0032] The terms used in the present application are merely used to describe specific embodiments, and are not intended to limit the scope of protection of the present application. The singular forms "a," "an," and "the" used in the specification and claims of the present application are also intended to include the plural forms unless the context clearly indicates otherwise.

[0033] It should be understood that the use of terms such as "first" or "second", etc., employed in the description and the claims of the present application are used and should not be construed as indicating either an ordinal sequence or a specific priority or importance, but are merely used to distinguish one feature from another. Similarly, the use of terms such as "one" or "a" or "the" or "said" or "this" or "that" or "their" or "these" or "those" or similar words, are not intended to refer to one and only one unless specifically stated, but instead refer to one or more. Unless otherwise indicated, the words "front", "back", "up", "down", "top", "bottom", etc., are used for convenience and are not intended to be limiting as to a particular position or spatial orientation. The use of the words "include", "includes", "including", "contain", "contains", "containing", etc., is meant to be an open-ended term that is intended to encompass the elements listed, but also other elements not specifically listed. If it is stated that "a plurality" is present, this means two or more.

[0034] Referring to Figures 1 to 10 , the present application discloses a fan structure, which is part of a fan assembly. The fan structure comprises a fan blade assembly and a driving assembly, the driving assembly comprising a driving member, a housing 3 and a magnet 4 capable of being driven to rotate by the driving member, the fan blade assembly, the housing 3 and the magnet 4 being assembled together so as to realize the rotation of the fan blade assembly driven by the driving member. The driving member is an electric motor.

[0035] The fan blade assembly comprises a fan blade 1 and a heat dissipation member 2, the heat dissipation member 2 being connected to the fan blade 1 and used for heat dissipation of the electric motor of the fan assembly.

[0036] The fan blade 1 is made of plastic material, which is light in weight and convenient for injection molding. Referring to Figure 2 , the fan blade 1 comprises a cover 11, a plurality of blades 12 and a support ring 13, the plurality of blades 12 being arranged between the support ring 13 and the cover 11, both ends of the plurality of blades 12 being connected to the outer peripheral side of the cover 11 and the inner peripheral side of the support ring 13 respectively, and the support ring 13 being conducive to increasing the structural strength of the fan blade 1.

[0037] Specifically, referring to Figure 2 , the cover 11 has a cavity 110, and the cover 11 comprises a peripheral wall portion 11a and a bottom wall portion 11b connected to the peripheral wall portion 11a perpendicularly, the peripheral wall portion 11a comprising an outer peripheral surface 111 and an inner peripheral surface 112, the plurality of blades 12 being connected to the outer peripheral surface 111, and the inner peripheral surface 112 being located at the periphery of the cavity 110, i.e. the inner peripheral surface 112 being exposed to the cavity 110.

[0038] Referring to Figure 2 , the cover 11 further comprises a plurality of reinforcing ribs 11c, the plurality of reinforcing ribs 11c being arranged in a circle and arranged at the connection between the peripheral wall portion 11a and the bottom wall portion 11b. Correspondingly, referring to Figure 5 and Figure 6The plurality of reinforcing ribs 11c are connected to the inner circumferential surface 112 of the circumferential wall portion 11a and the inner bottom surface 116 of the bottom wall portion 11b, so as to improve the structural strength of the joint between the circumferential wall portion 11a and the bottom wall portion 11b.

[0039] Referring to Figure 3 and Figure 4 , the bottom wall portion 11b is provided with a plurality of heat dissipation holes 114, which are arranged in a circle. The bottom wall portion 11b is provided with at least one heat dissipation hole 114 in the area surrounded by two adjacent reinforcing ribs 11c, which is conducive to accelerating the heat dissipation of the motor.

[0040] The heat dissipation member 2 is made of metal, referring to Figure 1 , Figure 2 and Figure 5 , the heat dissipation member 2 is at least partially located in the cavity 110 of the cover 11. The heat dissipation member 2 comprises an outer ring 21, an inner ring 22 and a plurality of fins 23. The plurality of fins 23 are connected to the outer ring 21 and the inner ring 22. At least part of the outer ring 21 is embedded in the wall portion of the cover 11. At least part of the fins 23 and the inner ring 22 are located in the cavity 110. Since the fan blade 1 is made of plastic material, it has a large size and the thickness of the wall portion is relatively thin. In the case of high-speed operation of the fan assembly, the cover 11 of the fan blade 1 is subjected to a large stress. If the strength of the cover 11 is not good, it is easy to deform and produce imbalance, which affects the NVH performance of the whole vehicle. In the present application, part of the heat dissipation member 2 is embedded in the wall portion of the cover 11. The outer ring 21 of the heat dissipation member 2 supports the cover 11 of the fan blade 1, effectively improving the structural strength and rigidity of the cover 11. The plurality of fins 23 of the heat dissipation member 2 disperse the stress of the cover 11 to the inner ring 22. In the case of high-speed operation of the fan assembly, the fan blade 1 is not easy to deform, which is conducive to the balanced operation of the fan assembly and optimizes the NVH performance of the whole vehicle.

[0041] The outer ring 21, the inner ring 22 and the circumferential wall portion 11a of the cover 11 are concentrically arranged. The outer ring 21, the outer circumferential surface 111 of the cover 11 and the inner circumferential surface 112 of the cover 11 are coaxially arranged, so that the outer ring 21 stably supports the cover 11. In addition, the plurality of fins 23 are uniformly arranged between the outer ring 21 and the inner ring 22 in the circumferential direction, so that the stress of the cover 11 can be uniformly dispersed to the inner ring 22.

[0042] In some embodiments, referring to Figure 5 and Figure 6 , the cover 11 completely covers the outer ring 21. The outer ring 21 is located between the outer circumferential surface 111 and the inner circumferential surface 112 of the cover 11. The axial height of the outer ring 21 is close to the axial height of the cover 11, which improves the supporting strength of the cover 11. Part of the fins 23 is also embedded in the circumferential wall portion 11a of the cover 11, which supports the circumferential wall portion 11a. In some other possible embodiments, the cover 11 can also cover part of the outer ring 21.

[0043] The outer side surface of the outer ring 21 and the outer peripheral surface 111 of the peripheral wall portion 11a have a first distance, and the inner side surface of the outer ring 21 and the inner peripheral surface 112 of the peripheral wall portion 11a have a second distance, and the first distance is equal to or different from the second distance.

[0044] The plurality of fins 23 are vertically connected with the outer ring 21 and the inner ring 22, and the height of the outer ring 21, the height of the inner ring 22 and the height of the fin 23 are equal in the axial direction of the heat dissipation member 2, so that the overall structural strength of the heat dissipation member 2 is high. The motor of the fan assembly is mainly cooled by the plurality of fins 23, and the outer ring 21 and the inner ring 22 are used for auxiliary cooling of the motor. As the power of the motor becomes larger and larger, the heat generation also becomes larger and larger, and high temperature affects the thermal stability of the permanent magnet, causing demagnetization to affect performance, and high temperature also causes aging of other parts, affecting product life. The present application sets the heat dissipation member 2, the inner side end surface of the inner ring 22 of the metal heat dissipation member 2 directly contacts the outer side end surface of the shell 3, and the heat is directly led out through the heat dissipation member 2, improving the cooling effect of the motor and effectively reducing the temperature, thereby reducing the demagnetization of the permanent magnet caused by temperature and reducing the aging of the product caused by high temperature, improving the product life and reliability. In addition, the cover 11 is provided with a plurality of cooling holes 114, which can increase the air flow and improve the cooling efficiency of the heat dissipation member 2.

[0045] The plurality of fins 23 correspond to the plurality of reinforcing ribs 11c, that is, the number of fins 23 is equal to the number of reinforcing ribs 11c. Referring to Figures 6 to 8 Each reinforcing rib 11c corresponds to a part of the cladding fin 23, that is, a part of the fin 23 is embedded in the reinforcing rib 11c, which can improve the support strength of the reinforcing rib 11c; in the axial direction of the heat dissipation member 2, the height of the fin 23 is greater than the height of the reinforcing rib 11c, and a part of the fin 23 is exposed in the cavity 110 of the cover 11, which is conducive to heat dissipation, and the larger the area of the fin 23 exposed in the cavity 110, the better the heat dissipation effect.

[0046] In some embodiments, referring to Figures 8 to 10 The reinforcing rib 11c includes an outer end surface 113, which is an arc surface recessed towards the bottom wall portion 11b, that is, the outer end surface 113 is an arc surface recessed inward, compared with the inclined surface of the outer end surface of the reinforcing rib 11c, the outer end surface 113 is set to be an arc surface recessed inward, which can reduce the cladding area of the reinforcing rib 11c to the fin 23, and can provide better support strength.

[0047] In this embodiment, referring to Figure 8The inner ring 22 of the heat dissipation member 2 is located in the cavity 110, and the inner ring 22 and the plurality of fins 23 are connected with the inner bottom surface 116 of the bottom wall part 11b, i.e. the inner ring 22 and the plurality of fins 23 are not embedded in the bottom wall part 11c, so that the thickness requirement of the bottom wall part 11b is not high, and the manufacturing is easy. Since the peripheral wall part 11a is subjected to a large force during high-speed rotation of the fan assembly, the embedding of the outer ring 21 in the peripheral wall part 11a can meet the strength requirement.

[0048] Referring to Figure 8 The manufacturing Figure 10 The plurality of connecting parts 11d are connected between any two adjacent reinforcing ribs 11c, and are arranged around the inner ring 22 and connected with the wall surface (outer wall surface) of the inner ring 22 facing the inner peripheral surface 112, i.e. the plurality of connecting parts 11d cover part of the outer wall surface of the inner ring 22. By arranging the connecting part 11d and covering part of the inner ring 22, stable support is provided by the inner ring 22, and the structural strength of the shell 11 is further improved.

[0049] In this embodiment, the fan blade 1 and the heat dissipation member 2 are integrally injection molded. The specific manufacturing process is as follows: first, the heat dissipation member 2 is placed in the cavity of the encapsulation mold, and then the liquid injection liquid is injected into the cavity of the encapsulation mold by using an injection molding machine to partially encapsulate the heat dissipation member 2 to form the shell 11 and the plurality of reinforcing ribs 11c, and at the same time, the plurality of blades 12 and the support ring 13 are formed outside the shell 11.

[0050] In this embodiment, the heat dissipation member 2 is a one-piece member, and the material of the heat dissipation member 2 is aluminum alloy with high heat dissipation coefficient. In some other possible embodiments, the material of the heat dissipation member 2 can also be steel.

[0051] The casing 3 is mounted in the space surrounded by the inner ring 22 and the bottom wall part 11b, and during assembly, the casing 3 is press-fitted in the space to make the casing 3 and the inner ring 22 in interference fit. In the related art, the casing and the fan blade are connected through fasteners (such as bolts), and the fasteners are connected through the through holes of the fan blade and the threaded holes of the casing. This mode has the following disadvantages: first, the fasteners are prone to looseness, which causes abnormal noise or failure to fall off; second, the fasteners have strict requirements on the tightening torque and the effective number of threads, and due to the limited wall thickness and hole flange height of the casing caused by process reasons, the effective number of threads is too small, which also causes that only the number of fasteners can be increased; third, the initial static balance and dynamic balance are too large, and the balance block needs to be increased or the weight needs to be reduced to meet the requirements of static balance and dynamic balance detection, which increases the workload of balancing test of the fan blade in the workshop during production, reduces the yield and production efficiency; fourth, the contact area between the fan blade and the casing is small, and the NVH performance is not good when the fan assembly is running at high speed. At least two reasons cause the initial static balance and dynamic balance to be too large, the first reason is that there is a gap between the through hole of the fan blade and the threaded hole of the casing, which causes the center lines of the fan blade and the casing to be different in axis, and the eccentricity causes the fan blade to vibrate unbalancedly; the second reason is that only the fasteners are used for connection during the installation of the fan blade and the casing, and there is no coaxial positioning, which causes eccentricity and imbalance. The casing 3 and the inner ring 22 are connected in interference instead of fasteners, which has at least the following advantages: first, the casing 3 and the fan blade 1 are stably connected, and the casing 3 and the fan blade 1 are not prone to separation; second, no holes need to be provided in the fan blade 1 and the casing 3, and no flange processing is needed for the casing 3, which simplifies the process, saves the number of fasteners, and reduces the cost; third, the casing 3 is pressed into the inner ring 22, so that the outer wall surface of the casing 3 and the inner wall surface of the inner ring 22 are connected in interference, which is centered, and under the condition of not considering the error, the axis of the casing 3 coincides with the axis of the inner ring 22, so that all parts are designed to be axisymmetric, which effectively reduces the initial static balance and dynamic balance, reduces the workload of balancing test of the fan blade 1 in the workshop during production, improves the yield and production efficiency; fourth, the contact and support area between the outer wall surface of the casing 3 and the inner wall surface of the inner ring 22 is large, which makes the NVH performance good when the fan assembly is running at high speed.

[0052] The area surrounded by the inner ring 22 of the bottom wall part 11b is provided with a through hole 115, which can be passed through by a tool, facilitating the tool to apply force to the casing 3 for disassembling the casing 3; during press-fitting, if the space surrounded by the inner ring 22, the bottom wall part 11b and the casing 3 is a closed space, it is easy to be difficult to press-fit due to the gas trapped, and the through hole 115 solves the problem of difficult press-fitting; in addition, the through hole 115 can also be used to observe whether the casing 3 is press-fitted in place; during balance detection, a tool can pass through the through hole 115 to cut the part with uneven weight distribution on the casing 3, so as to realize the final static balance and dynamic balance.

[0053] In some embodiments, referring to Figure 3 and Figure 4 The bottom wall part 11b is provided with a plurality of through holes 115, which are arranged equidistantly around the inner ring 22, so as to balance the center of gravity of the fan leaf 1.

[0054] The casing 3 is an integral part, referring to Figure 2 The casing 3 includes a shell 31 and a bearing mounting part 32 connected to the shell 31, the shell 31 includes a bottom shell part 311 and a peripheral shell part 312, the bearing mounting part 32 is located in the central region of the bottom shell part 311 and extends in the same direction as the peripheral shell part 312, and the bottom shell part 311, the peripheral shell part 312 and the bearing mounting part 32 are coaxial. The magnet 4 is installed in the shell 31 and connected to the inner wall of the peripheral shell part 312. The space between the magnet 4 and the bearing mounting part 32 is used to install the stator winding, and the bearing mounting part 32 is used to install the bearing, and the rotating shaft of the motor is rotatably connected with the bearing, and the motor is rotated through the motor-driven fan structure.

[0055] In the related art, in order to dissipate heat from the motor, a plurality of heat dissipation holes are usually provided on the casing, but the plurality of heat dissipation holes reduce the strength, rigidity and stability of the casing, and dust and water vapor can enter the interior of the casing through the heat dissipation holes, affecting the performance of the motor. The casing 3 provided in the present application does not have heat dissipation holes, so that the strength, rigidity and stability of the casing 3 are not affected by the heat dissipation holes, and the possibility of dust and water vapor entering the interior and accumulating is reduced, the use environment is optimized, the product life and reliability are improved.

[0056] The above embodiments are only used to illustrate the technical solutions described in the present application and not to limit the present application. The understanding of the present application should be based on the technical personnel in the art. Although the present application has been described in detail with reference to the above embodiments, those skilled in the art should understand that the technical personnel in the art can still modify or equivalently replace the present application, and all technical solutions and improvements which do not deviate from the spirit and scope of the present application should be covered in the scope of the claims of the present application.

Claims

1. A fan structure characterized by, The fan structure comprises: a fan blade (1) comprising a cover shell (11) and a plurality of blades (12) connected to the outer peripheral side of the cover shell (11); and a heat dissipation piece (2) located at least partially in a cavity (110) of the cover shell (11), the heat dissipation piece (2) comprising an outer ring (21), an inner ring (22) and a plurality of fins (23) connected to the outer ring (21) and the inner ring (22), at least a portion of the outer ring (21) being embedded in a wall portion of the cover shell (11), the cover shell (11) comprising a peripheral wall portion (11a) and a bottom wall portion (11b) connected to the peripheral wall portion (11a), and at least a portion of the outer ring (21) being embedded in the peripheral wall portion (11a); the cover shell (11) further comprises a plurality of reinforcing ribs (11c) corresponding to the plurality of fins (23), each of the reinforcing ribs (11c) corresponding to a portion of the fin (23). The fan blade (1) is made of plastic material, and the heat dissipation piece (2) is made of metal material, and the fan blade (1) and the heat dissipation piece (2) are integrally injection molded.

2. The fan structure of claim 1, wherein The cover shell (11) is provided with a through hole (115) in the area surrounded by the inner ring (22).

3. The fan structure of claim 1, wherein The fan structure comprises a driving assembly, the driving assembly comprising a driving member and a machine shell (3) capable of being driven to rotate by the driving member, 4. The fan structure of claim 1, wherein the machine shell (3) is installed in the space surrounded by the inner ring (22) and the bottom wall portion (11b), and the machine shell (3) is in interference fit with the inner ring (22), the driving assembly further comprises a magnet (4) installed in the machine shell (3). The peripheral wall portion (11a) comprises an outer peripheral surface (111) and an inner peripheral surface (112), the plurality of blades (12) are connected to the outer peripheral surface (111), the inner peripheral surface (112) is located at the periphery of the cavity (110), and the outer ring (21) is located between the outer peripheral surface (111) and the inner peripheral surface (112).

5. The fan structure according to any one of claims 1 to 4, wherein The outer ring (21), the outer peripheral surface (111) and the inner peripheral surface (112) are coaxially arranged.

6. The fan structure of claim 5, wherein The plurality of reinforcing ribs (11c) are connected to the inner peripheral surface (112) of the peripheral wall portion (11a) and an inner bottom surface (116) of the bottom wall portion (11b).

7. The fan structure of claim 5, wherein The reinforcing rib (11c) comprises an outer end surface (113) which is an arc-shaped surface recessed towards the bottom wall portion (11b), any two adjacent reinforcing ribs (11c) are connected by a connecting portion (11d), the inner ring (22) is located in the cavity (110), and a plurality of connecting portions (11d) are arranged around the inner ring (22) and connected to the wall surface of the inner ring (22) facing the inner peripheral surface (112).

8. The fan structure of claim 7, wherein ​ 9. The fan structure of claim 7, wherein The bottom wall part (11b) is provided with a plurality of heat dissipation holes (114), the plurality of heat dissipation holes (114) are arranged in a circle, and the bottom wall part (11b) is provided with at least one heat dissipation hole (114) in the area surrounded by two adjacent reinforcing ribs (11c).

10. The fan structure of claim 1, wherein The fan blade (1) comprises a supporting ring (13), and a plurality of the blades (12) are connected between the supporting ring (13) and the shell (11).

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