Fan unit

Abstract

A fan device includes a hub and a plurality of blades. Each blade includes a wind-repelling surface, and the wind-repelling surface includes a first tooth row and a second tooth row. The first tooth row includes a plurality of first tooth units, each of which includes a first body, a first central ridge and two first side ridges protruding from the surface of the first body, and a notch formed between two adjacent first tooth units. The second tooth row includes a plurality of second tooth units, each of which includes a second body and an extension member, a second central ridge and two second side ridges protruding from the surface of the second body, the extension member being located in the notch and including an extension rib, one end of the extension rib being connected to the second central ridge, and the other end of the extension rib extending to between two adjacent first side ridges of two adjacent first tooth units.

Description

Technical Field

[0001] The present invention relates to a heat dissipation device, and in particular to a fan device. Background Art

[0002] Generally, electronic components installed in electronic devices will gradually increase in temperature over time. To prevent the performance and lifespan of electronic components from being affected by high temperatures, electronic devices are often equipped with cooling fans. The rotation of the cooling fans drives air flow, thereby dissipating heat from the electronic components.

[0003] With the rapid development of the electronics industry, the performance requirements of electronic components are constantly increasing, resulting in higher temperatures during operation. Therefore, cooling fans need to simultaneously increase their speed and air volume to enhance the cooling effect. However, as the speed and air volume of cooling fans increase, the noise generated during fan operation also increases, affecting the user experience. However, the blades of current cooling fans mostly use a smooth surface, which does not help to improve the noise problem of cooling fans. Summary of the Invention

[0004] An object of the present invention is to provide a fan device to solve at least one of the above problems.

[0005] In view of the above, in one embodiment, a fan device is provided including a hub and a plurality of blades. The hub includes a central axis and an outer circumference, and the outer circumference surrounds the central axis. A plurality of blades are arranged at equal angles on the outer circumference, and each blade extends in a direction away from the central axis. Each blade includes a wind-repelling surface, and the wind-repelling surface includes a first tooth row and a second tooth row. The first tooth row includes a plurality of first tooth units, and the plurality of first tooth units are arranged side by side with each other in a direction away from the central axis. Each first tooth unit includes a first body, and a first central ridge and two first side ridges are convexly provided on the surface of the first body, and two first guide grooves are formed between the first central ridge and the two first side ridges, and a gap is formed between two adjacent first tooth units. The second tooth row includes a plurality of second skin tooth units, which are arranged side by side with each other in a direction away from the central axis. Each second skin tooth unit includes a second body and an extension piece. A second central ridge and two second side ridges are protruding from the surface of the second body. Two second guide grooves are formed between the second central ridge and the two second side ridges. The extension piece is located in the groove and includes an extension rib. One end of the extension rib is connected to the second central ridge, and the other end of the extension rib extends between two adjacent first side ridges of two adjacent first skin tooth units.

[0006] In summary, the fan device according to the embodiments of the present invention, by providing multiple tooth rows on the wind-displacing surface of the fan blade, allows airflow to be cut by each tooth unit in the tooth row and flow into the guide groove of each tooth unit, forming a vortex, thereby achieving the effects of guiding airflow and reducing wind resistance, thereby significantly reducing the noise generated by the fan device during use. Furthermore, the provision of extended ribs on each second tooth unit can guide airflow smoothly into the guide grooves of different tooth units, allowing the airflow to undergo multiple resistance reduction processes, further reducing the noise generated by the fan device during use. BRIEF DESCRIPTION OF THE DRAWINGS

[0007] Figure 1 FIG1 is a perspective view of a fan device according to an embodiment of the present invention.

[0008] Figure 2 FIG. 1 is a side view of a fan device according to an embodiment of the present invention.

[0009] Figure 3 FIG1 is a partial perspective view of an embodiment of a fan device according to the present invention.

[0010] Figure 4 A partial plan view of a fan blade according to an embodiment of the fan device of the present invention.

[0011] Figure 5 FIG. 2 is another partial perspective view of an embodiment of a fan device according to the present invention.

[0012] Figure 6 FIG. 1 is a flow diversion diagram of a fan device according to an embodiment of the present invention.

[0013] Figure 7 Another partial plan view of the fan blades of an embodiment of the fan device of the present invention.

[0014] Figure 8 This is another partial plan view of the fan blades of an embodiment of the fan device of the present invention.

[0015] The reference numerals are as follows:

[0016] 1: Fan device

[0017] 3, 5: Area

[0018] 10: Wheels

[0019] 11: Central axis

[0020] 12: Outer ring

[0021] 20: Fan blades

[0022] 21: Wind-repellent

[0023] 22: Leeward

[0024] 23: First side edge

[0025] 24: Second side edge

[0026] 25: Third side edge

[0027] 26: Fourth side edge

[0028] 30: First tooth row

[0029] 31: First dermatophagous unit

[0030] 32: The first ontology

[0031] 33: Missing slot

[0032] 34: protrusion

[0033] 35: First Middle Ridge

[0034] 36: First side ridge

[0035] 37: First diversion channel

[0036] 38: Top edge

[0037] 381: Front Edge

[0038] 382: Middle section

[0039] 383: Trailing Edge

[0040] 40: Second gear row

[0041] 41: Second skin tooth unit

[0042] 42: Second Body

[0043] 43: Extension

[0044] 44: Missing slot

[0045] 45: Second Middle Ridge

[0046] 46: Second side ridge

[0047] 47: Second diversion channel

[0048] 48: Extension rib

[0049] 49: Diversion groove

[0050] 50: Third gear row

[0051] 51: Third skin tooth unit

[0052] 52: The Third Body

[0053] 53: Extension

[0054] 54: protrusion

[0055] 55: Third Middle Ridge

[0056] 56: Third lateral ridge

[0057] 57: The third diversion channel

[0058] 58: Extension rib

[0059] 59: Diversion groove

[0060] L1, L2, L3: long axis

[0061] S1, S2, S3: short axis

[0062] H1, H2: Height

[0063] A, A1, A2, A3: Airflow

[0064] W: Vortex DETAILED DESCRIPTION

[0065] Figure 1 This is a perspective view of an embodiment of a fan device of the present invention. Figure 2 FIG. 1 is a side view of an embodiment of a fan device of the present invention. Figure 1 and Figure 2 As shown, the fan device 1 includes a hub 10 and a plurality of blades 20 , wherein the fan device 1 can be installed on various electronic products, such as computers, servers, or home appliances, to dissipate heat from heating elements installed in the electronic products.

[0066] like Figure 1 and Figure 2 As shown, the hub 10 includes a central axis 11 and an outer ring 12 , wherein the outer ring 12 surrounds the central axis 11 , wherein the hub 10 is used to connect to a driving element (such as a motor) to drive the hub 10 to rotate about its central axis 11 through the driving element.

[0067] like Figure 1 and Figure 2 As shown, multiple blades 20 are arranged at equal angles on the outer circumference 12 of the hub 10, and each blade 20 extends away from the central axis 11. When the hub 10 is driven to rotate, it can drive the multiple blades 20 to rotate synchronously to drive air flow, thereby dissipating heat from the heating element. The number of blades 20 can be more than two, depending on the actual product requirements. For example, in this embodiment, the number of blades 20 is 11 and they are arranged at equal angles (in this case, the angle is approximately 32.7°) around the central axis 11 of the hub 10.

[0068] In some embodiments, the blades 20 and the hub 10 may be integrally formed. Figure 1 and Figure 2As shown, for example, each blade 20 and hub 10 may be integrally formed by injection molding or casting. Alternatively, each blade 20 and hub 10 may be assembled, for example, each blade 20 may be attached to outer circumference 12 of hub 10 by adhesive bonding, snap fastening, or welding, although the present invention is not limited thereto.

[0069] Figure 3 for Figure 1 A partial stereogram of area 3. Figures 1 to 3 As shown, each fan blade 20 includes a wind-discharging surface 21 and a leeward surface 22, wherein the wind-discharging surface 21 and the leeward surface 22 are two opposite surfaces of each fan blade 20. In addition, in this embodiment, each fan blade 20 is an elongated plate and includes a first side edge 23, a second side edge 24, a third side edge 25, and a fourth side edge 26, wherein the first side edge 23 and the second side edge 24 are two opposite long sides of the fan blade 20, and the first side edge 23 and the second side edge 24 extend in a direction away from the central axis 11, respectively, the third side edge 25 and the fourth side edge 26 are two opposite short sides of the fan blade 20, and the third side edge 25 is connected to the outer circumference 12 of the hub 10, and the fourth side edge 26 is away from the outer circumference 12 relative to the third side edge 25. However, the above embodiment is only an example. In some embodiments, the fan blade 20 may also be a plate of other shapes (such as square, oval, or other irregular shapes).

[0070] Figure 4 This is a partial plan view of the fan blades of an embodiment of the fan device of the present invention. Figure 3 and Figure 4 As shown, the wind-exiting surface 21 of each fan blade 20 includes at least two rows of teeth. For example, in this embodiment, the wind-exiting surface 21 of each fan blade 20 includes three rows of teeth (a first row of teeth 30, a second row of teeth 40, and a third row of teeth 50), but this is not limited to this. The wind-exiting surface 21 may also include two rows of teeth or more than four rows of teeth, depending on the size of each fan blade 20.

[0071] like Figures 2 to 4As shown, the first tooth row 30 on the wind-repelling surface 21 of the fan blade 20 includes a plurality of first tooth units 31, the second tooth row 40 includes a plurality of second tooth units 41, and the third tooth row 50 includes a plurality of third tooth units 51, wherein the plurality of first tooth units 31, the plurality of second tooth units 41 and the plurality of third tooth units 51 are respectively arranged side by side with each other in the direction away from the central axis 11 of the hub 10 (i.e., the direction from the third side edge 25 to the fourth side edge 26), and the first tooth row 30, the second tooth row 40 and the third tooth row 50 are further arranged into multiple rows from the first side edge 23 to the second side edge 24, forming the second tooth row 40 located between the first tooth row 30 and the third tooth row 50, so that the first tooth row 30 is adjacent to the first side edge 23 relative to the second tooth row 40, and the third tooth row 50 is adjacent to the second side edge 24 relative to the second tooth row 40.

[0072] In some embodiments, the fan blade 20, the first tooth row 30, the second tooth row 40 and the third tooth row 50 may be an integrally formed structure (eg, Figure 1 and Figure 2 As shown in FIG. 1 , for example, the fan blade 20 , the first tooth row 30 , the second tooth row 40 and the third tooth row 50 can be integrally manufactured by injection molding or casting.

[0073] Figure 5 for Figure 1 A partial stereogram of area 5. Figures 3 to 5 As shown, each first skin tooth unit 31 of the first tooth row 30 includes a first body 32, and a first central ridge 35 and two first side ridges 36 are protruding from the surface of the first body 32. The first central ridge 35 and each first side ridge 36 extend from the first side edge 23 toward the second side edge 24. The first central ridge 35 is located between the two first side ridges 36 and are arranged parallel to each other, so that two concave first guide grooves 37 are formed between the first central ridge 35 and the two first side ridges 36.

[0074] like Figures 3 to 5 As shown, in this embodiment, the first body 32 is kite-shaped with a long axis L1 and a short axis S1 that are perpendicular to each other. The long axes L1 of each first body 32 of each first dermal tooth unit 31 are parallel to each other, forming a plurality of first dermal tooth units 31 arranged side by side. The first central ridge 35 of the first body 32 is arranged along the long axis L1, and the two first side ridges 36 are respectively arranged at opposite ends of the short axis S1. The length of the first central ridge 35 is greater than the length of each first side ridge 36. In this embodiment, the length of the first central ridge 35 is greater than twice the length of the first side ridges 36, but this is not limited to this.

[0075] In addition, if Figures 3 to 5As shown, since the first body 32 of each first skin tooth unit 31 is in the shape of a kite, a notch 33 is formed between two adjacent first skin tooth units 31. For example, in this embodiment, a triangular notch 33 is formed between the two adjacent oblique sides of the two adjacent first skin tooth units 31 and the two adjacent first side ridges 36.

[0076] like Figures 3 to 5 As shown, each second skin tooth unit 41 of the second tooth row 40 includes a second main body 42 and an extension piece 43, wherein the structure of the second main body 42 may be the same as or similar to the structure of the above-mentioned first main body 32. For example, in the present embodiment, a second central ridge 45 and two second side ridges 46 are also protrudingly provided on the surface of the second main body 42. The second central ridge 45 and each second side ridge 46 extend from the first side edge 23 toward the second side edge 24. The second central ridge 45 is located between the two second side ridges 46 and are arranged parallel to each other, so that two concave second guide grooves 47 are respectively formed between the second central ridge 45 and the two second side ridges 46.

[0077] like Figures 3 to 5 As shown, in this embodiment, the second body 42 is also kite-shaped, having a long axis L2 and a short axis S2 that are perpendicular to each other. The long axes L2 of each second body 42 of each second dermal tooth unit 41 are parallel to each other, forming a plurality of second dermal tooth units 41 arranged side by side. The second central ridge 45 of the second body 42 is arranged along the long axis L2, and the two second side ridges 46 are respectively arranged at opposite ends of the short axis S2. The length of the second central ridge 45 is greater than the length of each second side ridge 46. In this embodiment, the length of the second central ridge 45 is greater than twice the length of the second side ridges 46, but this is not limited to this.

[0078] like Figures 3 to 5 As shown, in this embodiment, a plurality of first tooth units 31 and a plurality of second tooth units 41 are staggered with each other, so that each second tooth unit 41 corresponds to a notch 33 formed between two adjacent first tooth units 31, and the extension member 43 of each second tooth unit 41 is located within the notch 33. Here, the extension member 43 includes an extension rib 48, which is protruding from the wind-discharging surface 21 of the fan blade 20, and one end of the extension rib 48 is connected to the second middle ridge 45 of the second body 42, and the other end of the extension rib 48 extends between two adjacent first side ridges 36 of two adjacent first tooth units 31.

[0079] Therefore, please refer to Figure 3 、 Figure 4 and Figure 6 As shown, the fan device 1 of the embodiment of the present invention is provided with a plurality of tooth rows (such as the first tooth row 30 and the second tooth row 40) on the wind-discharging surface 21 of the fan blade 20. When the hub 10 rotates and drives the plurality of fan blades 20 to rotate, the airflow A (such as the first side edge 23 of each fan blade 20) entering Figure 6 As shown in the figure, the airflow A can be cut by the first middle ridge 35 of each first tooth unit 31 and introduced into the two first guide grooves 37 of each first tooth unit 31 to form a vortex W, so that the airflow A changes from sliding friction to rolling friction, thereby reducing wind resistance and preventing external air from re-entering the gaps in the fan blades 20, so that the gaps in the fan blades 20 are filled with low-speed and quiet airflow, thereby greatly reducing the noise during the operation of the fan device 1.

[0080] In addition, if Figure 6 As shown, by setting the extension ribs 48 of each second tooth unit 41, the airflow A1 flowing out of each first guide groove 37 toward the second side edge 24 can be guided by the extension ribs 48 and smoothly enter the second guide groove 47 of each second tooth unit 41 of the second tooth row 40, so that the airflow A1 can form a vortex W in the second guide groove 47 and further reduce the wind resistance, so as to further reduce the noise of the fan device 1 during use.

[0081] For example Figures 3 to 5 As shown, each third skin tooth unit 51 of the third tooth row 50 includes a third main body 52 and an extension piece 53, wherein the structure of the third main body 52 may be the same as or similar to the structure of the above-mentioned first main body 32. For example, in the present embodiment, a third central ridge 55 and two third side ridges 56 are also protrudingly provided on the surface of the third main body 52. ​​The third central ridge 55 and each third side ridge 56 extend from the first side edge 23 toward the second side edge 24. The third central ridge 55 is located between the two third side ridges 56 and are arranged parallel to each other, so that two concave third guide grooves 57 are respectively formed between the third central ridge 55 and the two third side ridges 56.

[0082] like Figures 3 to 5 As shown, in this embodiment, the third body 52 is also kite-shaped, having a long axis L3 and a short axis S3 that are perpendicular to each other. The long axes L3 of each third body 52 of each third dermal tooth unit 51 are parallel to each other, forming a plurality of third dermal tooth units 51 arranged side by side. The third central ridge 55 is arranged along the long axis L3, and the two third side ridges 56 are respectively arranged at opposite ends of the short axis S3. The length of the third central ridge 55 is greater than the length of each third side ridge 56. In this embodiment, the length of the third central ridge 55 is greater than twice the length of the third side ridges 56, but this is not limited to this.

[0083] like Figures 3 to 5 As shown, since the second body 42 of each second skin tooth unit 41 is in the shape of a kite, a notch 44 is formed between two adjacent second skin tooth units 41. For example, in this embodiment, a triangular notch 44 is formed between the two adjacent oblique sides of the two adjacent second skin tooth units 41 and the two adjacent second side ridges 46.

[0084] like Figures 3 to 5As shown, the plurality of third tooth units 51 and the plurality of second tooth units 41 are staggered with each other, so that each third tooth unit 51 corresponds to the notch 44 formed between two adjacent second tooth units 41, and the extension member 53 of each third tooth unit 51 is located in the notch 44. Here, the extension member 53 includes an extension rib 58, which is protruding from the wind-discharging surface 21 of the fan blade 20, and one end of the extension rib 58 is connected to the third central ridge 55 of the third body 52, and the other end of the extension rib 58 extends between two adjacent second side ridges 46 of two adjacent second tooth units 41.

[0085] Therefore, if Figure 6 As shown, through the arrangement of the above-mentioned third tooth row 50 and the extension rib 58, the airflow A2 flowing out of each second guide groove 47 toward the second side edge 24 can be guided by the extension rib 58 and smoothly enter the third guide groove 57 of each third tooth unit 51 of the third tooth row 50, so that the airflow A2 can form a vortex W in the third guide groove 57 and reduce the wind resistance multiple times, so as to further reduce the noise of the fan device 1 during use.

[0086] In some embodiments, the first body 32 of each first skin tooth unit 31, the second body 42 of each second skin tooth unit 41 and the third body 52 of each third skin tooth unit 51 can also be other polygons and not limited to kite shapes. For example, the polygons can be triangles, rhombuses or pentagons, etc.

[0087] like Figures 3 to 5 As shown, in this embodiment, the extension member 43 of each second tooth unit 41 further has two guide grooves 49. The two guide grooves 49 are located on opposite sides of the extension rib 48, and the two guide grooves 49 are connected to the two second guide grooves 47 of the second tooth unit 41 and the two adjacent first guide grooves 37 of the two adjacent first tooth units 31. In other words, the guide grooves 49 of the extension member 43 are connected between the first guide grooves 37 and the second guide grooves 47, so that the airflow A1 flowing out of the first guide grooves 37 toward the second side edge 24 can be guided by the guide grooves 49 and smoothly enter the second guide grooves 47, thereby further reducing wind resistance.

[0088] like Figures 3 to 5As shown, in this embodiment, the extended member 53 of each third tooth unit 51 also has two guide grooves 59. The two guide grooves 59 are located on opposite sides of the extended rib 58, and the two guide grooves 59 are connected to the two third guide grooves 57 of the third tooth unit 51 and the two adjacent second guide grooves 47 of the two adjacent second tooth units 41. In other words, the guide grooves 59 of the extended member 53 are connected between the second guide grooves 47 and the third guide grooves 57, so that the airflow A2 flowing out of the second guide grooves 47 toward the second side edge 24 can be guided by the guide grooves 59 and smoothly enter the third guide grooves 57, thereby further reducing wind resistance.

[0089] For example Figure 4 As shown, in this embodiment, the first body 32 of each first skin tooth unit 31 further has a protrusion 34, and the protrusion 34 protrudes out of the first side edge 23 of the fan blade 20. Therefore, please refer to Figure 6 As shown, the airflow A entering from the first side edge 23 of each blade 20 can achieve a better cutting effect due to the protrusion 34. In addition, in this embodiment, the edge of the protrusion 34 protruding from the first side edge 23 is a curved edge (here, an arc curve), so that the airflow A after being cut can be further guided by the curved edge and smoothly enter the two first guide grooves 37 of each first tooth unit 31, thereby achieving a further improved diversion effect.

[0090] like Figure 4 and Figure 5 As shown, in this embodiment, the third body 52 of the third skin tooth unit 51 further has a protruding portion 54, and the protruding portion 54 protrudes from the second side edge 24 of the fan blade 20. Here, the protruding portion 54 is pointed to avoid blocking the flow of air. In addition, as shown in FIG. Figure 6 As shown, when the airflow A3 flows out of the third guide groove 57 of the third tooth unit 51, it can also be guided by the pointed protrusion 54 to prevent the generation of uneven wake flow, thereby achieving the advantage of further reducing noise.

[0091] Figure 7 This is another partial plan view of the fan blades of an embodiment of the fan device of the present invention. Figure 7 As shown, in this embodiment, the height H1 of the first side ridge 36 of each first skin tooth unit 31 is lower than the height H2 of the first middle ridge 35, wherein the height H1 of the first side ridge 36 and the height H2 of the first middle ridge 35 may refer to the heights of the first side ridge 36 and the first middle ridge 35 protruding from the surface of the first body 32, respectively. Figures 5 to 7As shown, the taller first central ridge 35 effectively isolates and guides airflow. Furthermore, in conjunction with the shorter first side ridges 36, the vortex W formed within the first guide groove 37 produces a more effective turbine rotation effect, thereby achieving better drag and noise reduction. In some embodiments, the height of the second side ridges 46 of each second tooth unit 41 can also be lower than the height of the second central ridge 45, and the height of the third side ridges 56 of each third tooth unit 51 can also be lower than the height of the third central ridge 55. These details will not be repeated here.

[0092] Figure 8 FIG. 1 is another partial plan view of the fan blades of an embodiment of the fan device of the present invention. Figure 8 As shown, in this embodiment, the first central ridge 35 of each first tooth unit 31 includes a top edge 38, which has a leading edge 381, a middle section 382, ​​and a trailing edge 383. The middle section 382 is connected between the leading edge 381 and the trailing edge 383, and the leading edge 381 is closer to the first side edge 23 of the blade 20 than the trailing edge 383. Here, the leading edge 381 and the trailing edge 383 are inclined edges, and the height of the middle section 382 is greater than the height of the leading edge 381 and the height of the trailing edge 383. In other words, the top edge 38 of the first central ridge 35 has a variable height (i.e., higher in the middle and lower on both sides) rather than a uniform height, thereby improving the air diversion effect of the first central ridge 35.

[0093] In some embodiments, the top edge of the second ridge 45 of each second skin tooth unit 41 and the top edge of the third ridge 55 of each third skin tooth unit 51 may also have a height variation rather than a uniform height with the first ridge 35 to improve the diversion effect of the second ridge 45 and the third ridge 55, which will not be repeated here.

[0094] In summary, the fan device according to the embodiments of the present invention, by providing multiple tooth rows on the wind-displacing surface of the fan blade, allows airflow to be cut by each tooth unit in the tooth row and flow into the guide groove of each tooth unit, forming a vortex, thereby achieving the effects of guiding airflow and reducing wind resistance, thereby significantly reducing the noise generated by the fan device during use. Furthermore, the provision of extended ribs on each second tooth unit can guide airflow smoothly into the guide grooves of different tooth units, allowing the airflow to undergo multiple resistance reduction processes, further reducing the noise generated by the fan device during use.

Claims

1. A fan device, characterized in that: include: A hub including a central axis and an outer ring surrounding the central axis; as well as A plurality of fan blades are arranged at equal angles on the outer circumference, each of the fan blades extending in a direction away from the central axis, and each of the fan blades includes a wind-dispelling surface, and the wind-dispelling surface includes: a first tooth row comprising a plurality of first tooth units arranged side by side in a direction away from the central axis, each of the first tooth units comprising a first body, a first central ridge and two first side ridges protruding from a surface of the first body, two first guide grooves formed between the first central ridge and the two first side ridges, and a notch formed between two adjacent first tooth units; and A second tooth row includes a plurality of second skin tooth units, and the plurality of second skin tooth units are arranged side by side in a direction away from the central axis. Each of the second skin tooth units includes a second body and an extension piece. A second central ridge and two second side ridges are protruding from the surface of the second body. Two second guide grooves are formed between the second central ridge and the two second side ridges. The extension piece is located in the groove and includes an extension rib. One end of the extension rib is connected to the second central ridge, and the other end of the extension rib extends to between the two adjacent first side ridges of the two adjacent first skin tooth units.

2. The fan device according to claim 1, wherein The height of each of the first side ridges is lower than the height of the first central ridge.

3. The fan device according to claim 1, wherein The first body is kite-shaped and has a long axis and a short axis perpendicular to each other. The first central ridge is arranged along the long axis, and the two first side ridges are located at two opposite ends of the short axis.

4. The fan device according to claim 1, wherein The first central ridge includes a top edge having a front edge, a middle section and a rear edge. The middle section is connected between the front edge and the rear edge, and the height of the middle section is respectively greater than the height of the front edge and the height of the rear edge.

5. The fan device according to claim 1, wherein The extension piece also includes two guide grooves, which are respectively located on two opposite sides of the extension rib. The two guide grooves are connected to the two second guide grooves and the two adjacent first guide grooves of the two adjacent first skin tooth units.

6. The fan device according to claim 1, wherein Each of the fan blades includes a first side edge and a second side edge, the wind-repelling surface is located between the first side edge and the second side edge, the first tooth row is adjacent to the first side edge relative to the second tooth row, and the first body of each first tooth unit has a protrusion, which protrudes out of the first side edge.

7. The fan device according to claim 6, wherein The protrusion has a curved edge.

8. The fan device according to claim 1, wherein The wind-repellent surface also includes a third tooth row, the second tooth row is located between the first tooth row and the third tooth row, the third tooth row includes a plurality of third skin tooth units, and the plurality of third skin tooth units are arranged side by side with each other in a direction away from the center axis, each of the third skin tooth units includes a third body and another extension piece, a third middle ridge and two third side ridges are protruding on the surface of the third body, two third guide grooves are formed between the third middle ridge and the two third side ridges, and another notch is formed between the two adjacent second skin tooth units near the two ends of the third tooth row, the other extension piece is located in the other notch and includes another extension rib, one end of the other extension rib is connected to the third middle ridge, and the other end of the other extension rib extends to between the two adjacent second side ridges of the two adjacent second skin tooth units.

9. The fan device according to claim 8, wherein Each of the fan blades includes a first side edge and a second side edge, the wind-repelling surface is located between the first side edge and the second side edge, the third tooth row is adjacent to the second side edge relative to the second tooth row, and the third body of each third tooth unit has a protrusion, which protrudes out of the second side edge.

10. The fan device according to claim 9, wherein The protrusion is pointed.

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