Fan structure

Abstract

The invention discloses a fan structure which comprises a fan blade and a heat dissipation piece, the fan blade comprises a housing and a plurality of blades, and the blades are connected to the peripheral side of the housing; the heat dissipation part is at least partially located in the cavity of the housing, the heat dissipation part comprises an outer ring, an inner ring and a plurality of fins, the fins are connected with the outer ring and the inner ring, and at least part of the outer ring is embedded in the wall of the housing. According to the fan blade, the heat dissipation piece is arranged, at least part of the outer ring of the heat dissipation piece is embedded in the wall part of the housing, the housing of the fan blade is supported, the structural strength of the fan blade is effectively improved, and the fan blade is not prone to deformation when rotating at a high speed.

Description

Technical Field

[0001] The invention relates to a fan structure and belongs to the technical field of heat dissipation fans. Background Art

[0002] The fan assembly is an important part of the cooling system of the automobile engine. The fan assembly includes fan blades, a casing, permanent magnets, stator windings and a motor. The fan blades include multiple fan blade bodies and a cover. The multiple fan blade bodies are arranged circumferentially around the cover, and the cover is fixedly connected to the casing. Most of the fan blades are made of plastic, with large sizes and thin walls. When the fan assembly is running at high speed, the fan blade cover is subjected to large forces and is easily deformed and unbalanced, affecting the NVH performance of the vehicle. Summary of the invention

[0003] The object of the present invention is to provide a fan structure with high structural strength and low deformation resistance.

[0004] To achieve the above object, the present invention adopts the following technical solution:

[0005] A fan structure, comprising:

[0006] A fan blade, the fan blade comprising a casing and a plurality of blades, wherein the plurality of blades are connected to an outer peripheral side of the casing; and

[0007] A heat sink, wherein the heat sink is at least partially located in the cavity of the housing, the heat sink comprises an outer ring, an inner ring and a plurality of fins, the plurality of fins connect the outer ring and the inner ring, and at least a portion of the outer ring is embedded in the wall of the housing.

[0008] As a further improved technical solution of the present invention, the fan blades are made of plastic, the heat sink is made of metal, and the fan blades and the heat sink are integrally injection molded.

[0009] As a further improved technical solution of the present invention, a through hole is provided in the area of ​​the cover shell surrounded by the inner ring.

[0010] As a further improved technical solution of the present invention, the fan structure includes a driving assembly, and the driving assembly includes a driving member and a housing that can be driven to rotate by the driving member.

[0011] The housing comprises a peripheral wall portion and a bottom wall portion connected to the peripheral wall portion, the housing is installed in a space enclosed by the inner ring and the bottom wall portion, and the housing and the inner ring are interference fit.

[0012] The drive assembly further includes a magnet installed in the housing.

[0013] As a further improved technical solution of the present invention, the cover shell includes a peripheral wall portion and a bottom wall portion connected to the peripheral wall portion, the peripheral wall portion includes an outer peripheral surface and an inner peripheral surface, a plurality of blades are connected to the outer peripheral surface, the inner peripheral surface is located on 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 solution of the present invention, the outer ring, the outer peripheral surface and the inner peripheral surface are coaxially arranged.

[0015] As a further improved technical solution of the present invention, the cover shell further comprises a plurality of reinforcing ribs, wherein the plurality of reinforcing ribs are connected to 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 of the reinforcing ribs covers a portion of the fin.

[0017] As a further improved technical solution of the present invention, the reinforcing rib includes an outer end face, which is an arc-shaped surface recessed toward the bottom wall portion, and any two adjacent reinforcing ribs are connected by a connecting portion. The inner ring is located in the cavity, and a plurality of connecting portions are arranged around the inner ring and connected to the wall surface of the inner ring facing the inner circumferential surface.

[0018] As a further improved technical solution of the present invention, 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 at least one heat dissipation hole is provided in the area of ​​the bottom wall portion surrounded by two adjacent reinforcing ribs.

[0019] As a further improved technical solution of the present invention, the fan blade includes a support ring, and a plurality of the blades are connected between the support ring and the cover shell.

[0020] Compared with the prior art, the beneficial effects of the present invention are: by arranging a heat sink, the heat sink includes an outer ring, an inner ring and a plurality of fins, at least a portion of the outer ring is embedded in the wall of the cover shell to support the cover shell of the fan blade, thereby effectively improving the structural strength of the fan blade, and the multiple fins of the heat sink disperse the force of the cover shell to the inner ring, which is not easy to deform when the fan blade runs at high speed, is beneficial to the balanced operation of the fan blade, and optimizes the NVH performance of the whole vehicle; in addition, the heat sink can improve the heat dissipation effect at the fan blade, effectively reduce the temperature, thereby reducing the demagnetization of the magnet due to temperature, reducing the aging of the fan blade due to high temperature, and improving the life and reliability. BRIEF DESCRIPTION OF THE DRAWINGS

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

[0022] Figure 2 yes Figure 1 Schematic diagram of the decomposition of

[0023] Figure 3 yes Figure 1 A three-dimensional schematic diagram from another angle;

[0024] Figure 4 yes Figure 3 Schematic diagram of the decomposition of

[0025] Figure 5 yes Figure 1 A three-dimensional cross-sectional view of

[0026] Figure 6 yes Figure 5 A magnified schematic diagram of the middle A area;

[0027] Figure 7 yes Figure 1 A three-dimensional schematic diagram of the middle fan blade and the heat sink;

[0028] Figure 8 yes Figure 7 A magnified schematic diagram of the middle B area;

[0029] Fig. 9 It is a three-dimensional schematic diagram of the fan blade in the figure;

[0030] Fig.10 yes Fig. 9 Enlarged schematic diagram of area C in the middle. DETAILED DESCRIPTION

[0031] The exemplary embodiments of the present invention will be described in detail below in conjunction with the accompanying drawings. If there are several embodiments, the features of these embodiments can be combined with each other without conflict. When the description refers to the drawings, unless otherwise specified, the same numbers in different drawings represent the same or similar elements. The contents described in the following exemplary embodiments do not represent all embodiments consistent with the present invention; on the contrary, they are only examples of devices, products and / or methods consistent with some aspects of the present invention as recorded in the claims of the present invention.

[0032] The terms used in the present invention are only for the purpose of describing specific embodiments, and are not intended to limit the scope of protection of the present invention. The singular forms "a", "said" or "the" used in the specification and claims of the present invention are also intended to include plural forms, unless the context clearly indicates other meanings.

[0033] It should be understood that the words used in the specification and claims of the present invention, such as "first", "second" and similar words, do not indicate any order, quantity or importance, but are only used to distinguish the names of features. Similarly, words such as "one" or "an" do not indicate a quantitative limitation, but indicate the existence of at least one. Unless otherwise specified, words such as "front", "rear", "upper", "lower" and similar words appearing in the present invention are only for the convenience of explanation and are not limited to a specific position or a spatial orientation. Words such as "include" or "comprise" are an open-ended expression, meaning that the elements appearing before "include" or "comprise" include the elements appearing after "include" or "comprise" and their equivalents, which does not exclude that the elements appearing before "include" or "comprise" may also include other elements. If "several" appears in the present invention, it means two or more.

[0034] Reference Figures 1 to 10 As shown, the present invention discloses a fan structure, which is a part of a fan assembly. The fan structure includes a fan blade assembly and a driving assembly, and the driving assembly includes a driving member, a housing 3 that can be driven to rotate by the driving member, and a magnet 4. The fan blade assembly, the housing 3, and the magnet 4 are assembled together, so that the driving member drives the fan blade assembly to rotate. Among them, the driving member is a motor.

[0035] The fan blade assembly includes a fan blade 1 and a heat sink 2. The heat sink 2 is connected to the fan blade 1 and is used for dissipating heat from the motor of the fan assembly.

[0036] The fan blade 1 is made of plastic, which is light and convenient for injection molding. Figure 2 The fan blade 1 includes a cover shell 11, a plurality of blades 12 and a support ring 13. The plurality of blades 12 are arranged between the support ring 13 and the cover shell 11. The two ends of the plurality of blades 12 are respectively connected to the outer peripheral side of the cover shell 11 and the inner peripheral side of the support ring 13. The support ring 13 is beneficial to increase the structural strength of the fan blade 1.

[0037] For details, see Figure 2 The cover shell 11 has a cavity 110, and the cover shell 11 includes a peripheral wall portion 11a and a bottom wall portion 11b vertically connected to the peripheral wall portion 11a. The peripheral wall portion 11a includes an outer peripheral surface 111 and an inner peripheral surface 112. A plurality of blades 12 are connected to the outer peripheral surface 111, and the inner peripheral surface 112 is located at the periphery of the cavity 110, that is, the inner peripheral surface 112 is exposed to the cavity 110.

[0038] See also Figure 2 The housing 11 further comprises a plurality of reinforcing ribs 11c, which are arranged circumferentially and disposed at the connection between the peripheral wall portion 11a and the bottom wall portion 11b. Figure 5 and Figure 6A plurality of reinforcing ribs 11c are connected to the inner peripheral surface 112 of the peripheral wall portion 11a and the inner bottom surface 116 of the bottom wall portion 11b to improve the structural strength of the connection between the peripheral wall portion 11a and the bottom wall portion 11b.

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

[0040] The heat sink 2 is made of metal. Figure 1 , Figure 2 and Figure 5 , the heat sink 2 is at least partially located in the cavity 110 of the housing 11, and the heat sink 2 includes an outer ring 21, an inner ring 22 and a plurality of fins 23, the plurality of fins 23 connect the outer ring 21 and the inner ring 22, at least a portion of the outer ring 21 is embedded in the wall of the housing 11, and at least a portion of the fins 23 and the inner ring 22 are located in the cavity 110. Since the fan blade 1 is made of plastic, has a large size, and a thin wall, when the fan assembly is running at high speed, the housing 11 of the fan blade 1 is subjected to a large force. If the strength of the housing 11 is not good, it is easy to deform and cause imbalance, affecting the NVH performance of the entire vehicle. The present application embeds a portion of the heat sink 2 into the wall of the cover 11, and the outer ring 21 of the heat sink 2 supports the cover 11 of the fan blade 1, thereby effectively improving the structural strength and rigidity of the cover 11, and the multiple fins 23 of the heat sink 2 disperse the force of the cover 11 to the inner ring 22. When the fan assembly is in high-speed operation, the fan blade 1 is not easy to deform, which is beneficial to the balanced operation of the fan assembly and optimizes the NVH performance of the vehicle.

[0041] The outer ring 21, the inner ring 22 and the peripheral wall portion 11a of the cover shell 11 are concentrically arranged, and the outer ring 21, the outer peripheral surface 111 of the cover shell 11 and the inner peripheral surface 112 of the cover shell 11 are coaxially arranged, so that the outer ring 21 provides stable support for the cover shell 11. In addition, a plurality of fins 23 are evenly arranged circumferentially between the outer ring 21 and the inner ring 22, so that the force on the cover shell 11 can be evenly dispersed on the inner ring 22.

[0042] In some embodiments, see Figure 5 and Figure 6 The housing 11 completely covers the outer ring 21, and the outer ring 21 is located between the outer circumferential surface 111 and the inner circumferential surface 112 of the housing 11, and the axial height of the outer ring 21 is close to the axial height of the housing 11, thereby improving the support strength of the housing 11. A portion of the fins 23 is also embedded in the peripheral wall portion 11a of the housing 11, thereby supporting the peripheral wall portion 11a. In some other possible embodiments, the housing 11 may also cover a portion of the outer ring 21.

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

[0044] A plurality of fins 23 are vertically connected to the outer ring 21 and the inner ring 22. Along the axial direction of the heat sink 2, the height of the outer ring 21, the height of the inner ring 22 and the height of the fin 23 are all equal, so that the overall structural strength of the heat sink 2 is high. The motor of the fan assembly mainly dissipates heat through a plurality of fins 23, and the outer ring 21 and the inner ring 22 are used for auxiliary heat dissipation of the motor. As the power of the motor increases, the heat generation increases. High temperature affects the thermal stability of the permanent magnet, causing demagnetization to affect the performance. At the same time, high temperature will also cause the aging resistance of other parts, affecting the life of the product. In this application, by setting a heat sink 2, the inner end face of the inner ring 22 of the heat sink 2 made of metal material is in direct contact with the outer end face of the housing 3, and the heat is directly guided out through the heat sink 2, so as to improve the heat dissipation effect of the motor, effectively reduce the temperature, thereby reducing the demagnetization of the permanent magnet by temperature, and also reduce the aging of the product by high temperature, improve the product life and reliability, in addition, the cover 11 is provided with a heat dissipation hole 114, which can increase the air flow and improve the heat dissipation efficiency of the heat sink 2.

[0045] The plurality of fins 23 corresponds to the plurality of reinforcing ribs 11c, that is, the number of the fins 23 is equal to the number of the reinforcing ribs 11c. Figures 6 to 8 Each reinforcing rib 11c corresponds to a portion of the covered fin 23, that is, a portion of the fin 23 is embedded in the reinforcing rib 11c, which can improve the supporting strength of the reinforcing rib 11c; along the axial direction of the heat sink 2, the height of the fin 23 is greater than the height of the reinforcing rib 11c, and a portion of the fin 23 is exposed in the cavity 110 of the cover shell 11, which is beneficial to heat dissipation, and the larger the area of ​​the fin 23 exposed to the cavity 110, the better the heat dissipation effect.

[0046] In some embodiments, see Figures 8 to 10 The reinforcing rib 11c includes an outer end surface 113, which is an arc-shaped surface that is recessed toward the bottom wall portion 11b, that is, the outer end surface 113 is an inwardly concave arc-shaped surface. Compared with the outer end surface of the reinforcing rib 11c being an inclined surface, the outer end surface 113 being set as an inwardly concave arc-shaped surface can reduce the covering area of ​​the reinforcing rib 11c on the fin 23, and can provide better supporting strength.

[0047] In this embodiment, see Figure 8The inner ring 22 of the heat sink 2 is located in the cavity 110, and the inner ring 22 and the plurality of fins 23 are connected to the inner bottom surface 116 of the bottom wall 11b, that is, the inner ring 22 and the plurality of fins 23 are not embedded in the bottom wall 11c, so that the thickness requirement of the bottom wall 11b is not high and it is easy to manufacture. Since the peripheral wall 11a is subjected to great force during the high-speed rotation of the fan assembly, the strength requirement can be met by embedding the outer ring 21 in the peripheral wall 11a.

[0048] See also Figure 8 system Fig.10 Any two adjacent reinforcing ribs 11c are connected by a connecting portion 11d, and a plurality of connecting portions 11d are arranged around the inner ring 22 and connected to the wall surface (outer wall surface) of the inner ring 22 facing the inner peripheral surface 112, that is, a plurality of connecting portions 11d cover a portion of the outer wall surface of the inner ring 22. By providing the connecting portions 11d and covering a portion of the inner ring 22, the inner ring 22 provides stable support, thereby further improving the structural strength of the housing 11.

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

[0050] In this embodiment, the heat sink 2 is an integral part, and the material of the heat sink 2 is an aluminum alloy with a high heat dissipation coefficient. In some other possible embodiments, the material of the heat sink 2 can also be steel.

[0051] The housing 3 is installed in the space enclosed by the inner ring 22 and the bottom wall 11b. During assembly, the housing 3 is pressed into the space to make the housing 3 and the inner ring 22 have an interference fit. In the related art, the housing and the fan blades are connected by fasteners (such as bolts), and the fasteners pass through the through holes of the fan blades and are connected to the threaded holes of the housing. This method has the following disadvantages: First, the fasteners are easy to loosen, resulting in abnormal noise or failure to fall off; second, the fasteners have strict requirements on the tightening torque and the effective number of threads. Due to process reasons, the wall thickness of the housing and the height of the hole flange are generally limited, so the number of effective threads is too small, and large-size fasteners cannot be used, and the number of fasteners can only be increased; third, the initial static balance and dynamic balance are too large, and it is necessary to increase the balance block or reduce the weight to achieve the static balance and dynamic balance detection requirements, which will increase the workload of the balance test of the fan blades in the workshop during production, reduce the yield rate and production efficiency; fourth, the contact area between the fan blades and the housing mounting support is small, and the NVH is not good when the fan assembly runs at high speed. There are at least two reasons that lead to excessive initial static balance and dynamic balance. 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 final fan blade rotation centerline and the casing rotation centerline to be misaligned. The eccentricity causes the fan blade to jump unbalanced. The second reason is that the fan blade and the casing are only connected by fasteners during installation. There is no coaxial positioning, which leads to eccentricity and thus causes unbalanced jump. The present application uses an interference fit connection between the casing 3 and the inner ring 22 instead of a fastener connection, which has at least the following advantages: first, the casing 3 is stably connected to the fan blades 1, and the casing 3 is not easily separated from the fan blades 1; second, there is no need to set holes in the fan blades 1 and the casing 3, and there is no need to flanging the casing 3, which simplifies the process, while also saving the number of fasteners and reducing costs; 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 interference fit to achieve centering. Without considering errors, the axis of the casing 3 coincides with the axis of the inner ring 22, so that all parts are axially symmetrically designed, effectively reducing the initial static balance and dynamic balance, reducing the workload of the workshop fan blade 1 balancing test during production, and improving the yield rate and production efficiency; fourth, the outer wall surface of the casing 3 and the inner wall surface of the inner ring 22 have a large contact support area, so that the NVH performance is good when the fan assembly runs at high speed.

[0052] A through hole 115 is provided in the area of ​​the bottom wall 11b surrounded by the inner ring 22, and the through hole 115 can be passed through by a tool, so that the tool can apply force to the casing 3 for disassembling the casing 3; during the press-fitting process, if the space surrounded by the inner ring 22, the bottom wall 11b and the casing 3 is a closed space, air is easily trapped, resulting in a large press-fitting force and difficulty in press-fitting. The problem of difficult press-fitting is solved by providing the through hole 115; in addition, the through hole 115 can also be used to observe whether the casing 3 is press-fitted in place; when detecting the balance, the tool can pass through the through hole 115 to cut the part of the casing 3 with uneven weight distribution, thereby achieving the final static balance and dynamic balance.

[0053] In some embodiments, see Figure 3 and Figure 4 The bottom wall portion 11b is provided with a plurality of through holes 115, and the plurality of through holes 115 are arranged at equal intervals around the inner ring 22 in the circumferential direction to balance the center of gravity of the fan blade 1.

[0054] The housing 3 is an integral part, see Figure 2 The housing 3 includes a housing 31 and a bearing mounting portion 32 connected to the housing 31. The housing 31 includes a bottom housing portion 311 and a peripheral housing portion 312. The bearing mounting portion 32 is located in the central area of ​​the bottom housing portion 311 and extends in the same direction as the peripheral housing portion 312. The bottom housing portion 311, the peripheral housing portion 312 and the bearing mounting portion 32 are coaxial. The magnet 4 is installed in the housing 31 and connected to the inner wall of the peripheral housing portion 312. The space between the magnet 4 and the bearing mounting portion 32 is used to install the stator winding. The bearing mounting portion 32 is used to install the bearing. The motor shaft is rotatably connected to the bearing and rotates through the motor electric fan structure.

[0055] In the related art, in order to dissipate heat from the motor, a plurality of heat dissipation holes are usually provided in 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 casing through the heat dissipation holes, affecting the performance of the motor. The casing 3 provided in the present application is not provided with heat dissipation holes, so the strength, rigidity and stability of the casing 3 will not be affected by the heat dissipation holes, and the possibility of dust and water vapor entering and accumulating inside is reduced, thereby optimizing the use environment and improving the product life and reliability.

[0056] The above implementation modes are only used to illustrate the present invention and are not intended to limit the technical solutions described in the present invention. The understanding of the present invention should be based on the technical personnel in the relevant technical field. Although the present invention has been described in detail in this specification with reference to the above implementation modes, the ordinary technical personnel in the field should understand that the technical personnel in the relevant technical field can still modify or replace the present invention with equivalents, and all technical solutions and improvements thereof that do not depart from the spirit and scope of the present invention should be covered within the scope of the claims of the present invention.

Claims

1. A fan structure, characterized in that: include: A fan blade (1), the fan blade (1) comprising a casing (11) and a plurality of blades (12), the plurality of blades (12) being connected to the outer peripheral side of the casing (11); as well as A heat sink (2), wherein the heat sink (2) is at least partially located in the cavity (110) of the housing (11), the heat sink (2) comprises an outer ring (21), an inner ring (22) and a plurality of fins (23), the plurality of fins (23) connecting the outer ring (21) and the inner ring (22), and at least a portion of the outer ring (21) is embedded in the wall of the housing (11).

2. The fan structure according to claim 1, characterized in that: The fan blade (1) is made of plastic material, the heat sink (2) is made of metal material, and the fan blade (1) and the heat sink (2) are integrally injection molded.

3. The fan structure according to claim 1, characterized in that: A through hole (115) is provided in the area of ​​the cover shell (11) surrounded by the inner ring (22).

4. The fan structure according to claim 1, characterized in that: The fan structure comprises a driving assembly, wherein the driving assembly comprises a driving member and a housing (3) capable of being driven to rotate by the driving member. The cover shell (11) comprises a peripheral wall portion (11a) and a bottom wall portion (11b) connected to the peripheral wall portion (11a); the housing (3) is installed in a space enclosed by the inner ring (22) and the bottom wall portion (11b); the housing (3) and the inner ring (22) are interference fit. The driving assembly further comprises a magnet (4), wherein the magnet (4) is installed in the housing (3).

5. The fan structure according to any one of claims 1 to 4, characterized in that: The cover shell (11) comprises a peripheral wall portion (11a) and a bottom wall portion (11b) connected to the peripheral wall portion (11a); the peripheral wall portion (11a) comprises an outer peripheral surface (111) and an inner peripheral surface (112); a 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).

6. The fan structure according to claim 5, characterized in that: The outer ring (21), the outer peripheral surface (111) and the inner peripheral surface (112) are coaxially arranged.

7. The fan structure according to claim 5, characterized in that: The cover shell (11) further comprises a plurality of reinforcing ribs (11c), wherein the plurality of reinforcing ribs (11c) are connected to the inner peripheral surface (112) of the peripheral wall portion (11a) and the inner bottom surface (116) of the bottom wall portion (11b); The plurality of reinforcing ribs (11c) correspond to the plurality of fins (23), and each of the reinforcing ribs (11c) covers a portion of the fin (23).

8. The fan structure according to claim 7, characterized in that: The reinforcing rib (11c) comprises an outer end surface (113), wherein the outer end surface (113) is an arc-shaped surface that is recessed toward the bottom wall portion (11b), and any two adjacent reinforcing ribs (11c) are connected via 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 are connected to the wall surface of the inner ring (22) facing the inner peripheral surface (112).

9. The fan structure according to claim 7, characterized in that: The bottom wall portion (11b) is provided with a plurality of heat dissipation holes (114), the plurality of heat dissipation holes (114) are arranged in a circular pattern, and at least one heat dissipation hole (114) is provided in an area of ​​the bottom wall portion (11b) surrounded by two adjacent reinforcing ribs (11c).

10. The fan structure according to claim 1, characterized in that: The fan blade (1) comprises a support ring (13), and a plurality of blades (12) are connected between the support ring (13) and the cover shell (11).

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