Fan blade assembly and fan thereof

Abstract

The invention belongs to the technical field of ventilation equipment, and discloses a fan blade assembly which comprises a fan blade part and an air guide structure arranged at the bottom of the fan blade part, the fan blade part is a sweepback type fan blade or a sweepforward type fan blade, and the air guide structure is a fillet structure or a chamfer structure or an air guide cover; in the rotating direction when the fan blade part rotates forwards, the installation angle and the inclination angle of the fan blade part are configured in the mode that under the condition that the fan blade assembly is installed on an air duct support in a matched mode and a back plate is installed over the fan blade part, the fan blade part can be promoted to achieve the air outlet function when the fan blade part rotates backwards. According to the invention, the sweepback / sweepforward fan blades and the air guide structure are cooperatively arranged, an airflow separation point is delayed, and in combination with the rectification effect of the flow guide plate, the distance h between the shadow surface of the air inlet of the back plate and the air inlet of the fan is regulated and controlled, so that the fan blade P < lt > is formed; the technical bottleneck that a traditional centrifugal fan cannot output air in the reverse direction is solved.

Description

Technical Field

[0001] The present invention relates to the technical field of ventilation equipment, and particularly to a fan blade assembly and a fan thereof. Background Art

[0002] At present, there are many technical bottlenecks in the traditional fan in terms of air flow organization, operation efficiency and versatility. The existing axial fans generally adopt straight blades or non-swept axial fan blade designs, resulting in serious air flow separation and large eddy current losses. Especially under high-speed operating conditions, air flow separation is likely to occur, causing energy loss. In addition, the axial fan can meet the functional requirements during forward and reverse rotations, but it is limited by the installation space size; the centrifugal fan's forward and reverse rotation principles are both based on centrifugal force for air outlet, and reverse air outlet cannot be achieved. Summary of the Invention

[0003] The main object of the present invention is to provide a fan blade assembly and a fan thereof, aiming to solve the technical problems in the background art.

[0004] To achieve the above invention object, the first aspect of the present invention proposes a fan blade assembly, including:

[0005] A fan blade part and a wind guiding structure arranged at the bottom of the fan blade part, the fan blade part is a swept-back fan blade or a forward-swept fan blade, and the wind guiding structure is an inverted rounded corner structure, a chamfer structure or a wind guiding cover;

[0006] Along the rotation direction of the fan blade part during forward rotation, the installation angle and the inclination angle of the fan blade part are configured as:

[0007] When the fan blade assembly is adaptively installed on a duct bracket and a back plate is installed directly above the fan blade part, it can enable the fan blade part to achieve an air outlet function during reverse rotation; wherein, the wind guiding structure at the bottom of the fan blade part is located between the installation surface of the fan blade part and the duct bracket, and the fan blade part realizes an air inlet function during forward rotation.

[0008] In a possible implementation manner, the range of the installation angle of the fan blade part is from +15° to +45°, or from -15° to -45°, and the range of the inclination angle is from +25° to +50°, or from -25° to -50°.

[0009] In a possible implementation manner, when a back plate is installed directly above the fan blade part, the distance h between the fan blade part and the back plate is 15 - 50 mm, so that a preset static pressure difference is formed around the fan blade part when the fan blade part rotates in reverse.

[0010] In a possible implementation manner, the distance h between the fan blade part and the back plate is 28.9 ± 0.5 mm.

[0011] In a possible implementation, the preset static pressure difference is: Pblade < Pduct + Pbackplate, where P is the static pressure.

[0012] In a possible implementation, the radius of the rounded corner of the air guiding structure is 10%-15% of the chord length of the blade, which is used to optimize the air flow separation characteristics.

[0013] In a possible implementation, the top of the blade part is the air inlet surface of the fan, which is different from the air inlet surface of the duct of the fan. The height difference between the air inlet surface of the fan and the air inlet surface of the duct is less than the axial thickness of the blade part.

[0014] In a possible implementation, it further includes: a reinforcing ring, and the reinforcing ring is arranged on the annular surface formed by the rim of the blade part.

[0015] In a possible implementation, when the reinforcing ring is arranged at the upper port of the annular surface, the plane where the upper end surface of the reinforcing ring is located is the air inlet surface of the fan.

[0016] The present invention also protects a fan, including a blade assembly; the fan further includes:

[0017] A duct bracket adaptively installed with the blade assembly, and the air guiding structure at the bottom of the blade part is located between the blade part and the installation surface of the duct bracket.

[0018] In a possible implementation, the duct bracket is provided with an outlet system, and the outlet system includes N air outlets distributed at the bottom of the duct bracket, where N≥1 and N is an integer;

[0019] The outlet system is configured as:

[0020] When the blade part rotates forward, taking the centrifugal force generated by the blade part as the main driving force, combined with the axial lift to drive the air flow to enter the air inlet of the duct of the fan from the air inlet of the fan, and output through the outlet system.

[0021] In a possible implementation, the fan further includes:

[0022] A backplate, installed directly above the blade part;

[0023] The backplate is configured as:

[0024] When the blade part rotates in reverse, a preset static pressure difference is formed around the blade part, so that the sum of the static pressure provided by the backplate and the static pressure of the system impedance is greater than the static pressure of the fan itself, resulting in the air flow being output in the reverse direction from the air inlet of the fan.

[0025] In a possible implementation, the air duct bracket is further provided with an arc-shaped deflector for suppressing air flow turbulence and / or changing the air flow trajectory.

[0026] A fan blade assembly and a fan of the present invention have the following beneficial effects:

[0027] 1. The present invention adopts the coordinated setting of the swept-forward / swept-backward fan blade and the air guiding structure to delay the air flow separation point. Combining the rectifying effect of the deflector, by adjusting the distance h (15 - 50 mm, preferably 28.9 ± 0.5 mm) between the shadow surface of the back panel air inlet and the fan air inlet, a situation of P_fan < P_air duct + P_back panel (P is static pressure) is formed, solving the technical bottleneck that traditional centrifugal fans cannot blow air in the reverse direction.

[0028] 2. The present invention achieves efficient cooling in the forward rotation mode, cooperates with the static pressure difference to realize the thermal management function of the ventilation system, reduces the equipment maintenance frequency, and can be applied to industries such as refrigerator refrigeration and automobile seats. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 is a schematic structural diagram of a fan blade assembly and a fan according to an embodiment of the present invention;

[0030] Figure 2 is an exploded schematic diagram of a fan blade assembly and a fan according to an embodiment of the present invention;

[0031] Figure 3 is a schematic cross-sectional view of an air duct bracket of a fan blade assembly and a fan according to an embodiment of the present invention;

[0032] Figure 4 is a schematic structural diagram of a swept-back axial flow fan blade of a fan blade assembly and a fan according to an embodiment of the present invention;

[0033] Figure 5 is a fan blade assembly and a fan according to an embodiment of the present invention Figure 3 in a front view;

[0034] Figure 6 is a schematic cross-sectional structure diagram of a fan blade assembly and a fan according to an embodiment of the present invention;

[0035] Figure 7 is a schematic structural diagram of an air duct bracket according to an embodiment of the present invention;

[0036] Figure 8 is a schematic structural diagram of a back panel according to an embodiment of the present invention;

[0037] Figure 9 is a schematic diagram of an installation angle according to an embodiment of the present invention;

[0038] Figure 10Schematic diagram of the inclination angle according to an embodiment of the present invention;

[0039] Figure 11 Another cross-sectional structure schematic diagram of a fan blade assembly and its fan according to an embodiment of the present invention;

[0040] Figure 12 Another cross-sectional structure schematic diagram of a fan blade assembly and its fan according to an embodiment of the present invention;

[0041] Figure 13 Another perspective structure schematic diagram of a swept-back axial-flow fan blade of a fan blade assembly and its fan according to an embodiment of the present invention;

[0042] Figure 14 According to an embodiment of the present invention Figure 13 Top view structure schematic diagram;

[0043] Wherein:

[0044] 1 - air duct bracket; 101 - air outlet; 9 - swept-back fan blade or forward-swept fan blade; 10 - deflector; 11 - air guiding structure; 12 - reinforcement ring; 13 - back panel air outlet; 14 - back panel air inlet; 15 - fan air inlet; 16 - annular flow channel; 17 - mounting surface of the air duct bracket.

[0045] The realization, functional characteristics and advantages of the object of the present invention will be further described with reference to the embodiments and the accompanying drawings. Detailed implementation manners

[0046] It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0047] In the description of the present invention, it should be understood that the orientation or positional relationship indicated by the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as limiting the present invention. In addition, the terms "first" and "second" are only used for descriptive purposes and cannot be construed as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include one or more of the described features. In the description of the present invention, "a plurality" means two or more unless otherwise specifically defined.

[0048] In the description of the present invention, it should be noted that unless otherwise clearly specified and defined, the terms "installed", "connected", and "coupled" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection, a direct connection, or an indirect connection through an intermediate medium, and can be the communication inside two components or the interaction relationship between two components. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0049] In the present invention, unless otherwise clearly specified and defined, the first feature being "above" or "below" the second feature may include the direct contact between the first and second features, or may include the situation where the first and second features are not in direct contact but in contact through other features therebetween. Moreover, the first feature being "above", "over", and "on top of" the second feature includes the first feature being directly above and obliquely above the second feature, or merely indicating that the horizontal height of the first feature is higher than that of the second feature. The first feature being "below", "beneath", and "underneath" the second feature includes the first feature being directly below and obliquely below the second feature, or merely indicating that the horizontal height of the first feature is lower than that of the second feature.

[0050] Referring to Figures 1-14 , an embodiment of the present invention provides a fan blade assembly, including:

[0051] a fan blade portion and a wind guiding structure 11 provided at the bottom of the fan blade portion, the fan blade portion being a backward-swept fan blade or a forward-swept fan blade 9, and the wind guiding structure 11 being a rounded-corner structure, a chamfer structure, or a wind guiding cover;

[0052] Along the rotation direction when the fan blade portion rotates forward, the installation angle and the inclination angle of the fan blade portion are configured to:

[0053] When the fan blade assembly is adaptively installed on a duct bracket 1 and a back plate is installed directly above the fan blade portion, it can enable the fan blade portion to achieve an air outlet function when rotating in reverse; wherein, the wind guiding structure 11 at the bottom of the fan blade portion is located between the fan blade portion and the installation surface 17 of the duct bracket, and the fan blade portion achieves an air inlet function when rotating forward.

[0054] In a possible implementation manner, the top of the fan blade portion is the air inlet surface of the fan, which is different from the air inlet surface of the duct of the fan. The height difference between the air inlet surface of the fan and the air inlet surface of the duct is less than the axial thickness of the fan blade portion.

[0055] It should be noted that the top of the fan blade portion is defined as the air inlet surface of the fan. This air inlet surface is different from the air inlet surface of the duct (the inlet surface of the duct bracket 1), and there is a height difference between the two. This height difference should be less than the axial thickness of the fan blade portion to ensure smooth air inlet and matching with the duct.

[0056] The highest surface of the reinforcement ring 12 is the air inlet surface of the fan, and the air inlet surface is the air inlet surface of the air duct.

[0057] As Figures 9-10 shown, in a possible implementation, the range of the installation angle of the fan blade part is from +15° to +45°, or from -15° to -45°, and the range of the inclination angle is from +25° to +50°, or from -25° to -50°; the installation angle range is 15° - 45°; when a back plate is installed directly above the fan blade part, the distance h between the fan blade part and the back plate is 15 - 50 mm, so that when the fan blade part rotates in reverse, a preset static pressure difference is formed around the fan blade part. Preferably, the distance h between the fan blade part and the back plate is 28.9 ± 0.5 mm.

[0058] Among them, when the angle α is in the counterclockwise direction of the OB line segment, α is positive. Conversely, the angle is negative; before tilting, EF is perpendicular to the rib surface, and the ∠FEF' after tilting is the tilt angle β. When EF' is in the counterclockwise direction of EF, β is considered positive, and vice versa.

[0059] When both α and β are positive, in the top view of the fan (as Figure 14 shown), when the fan rotates clockwise, it is a forward rotation, and the air enters the air duct from the air inlet surface of the fan; when rotating in reverse, the air leaves the air duct through the air inlet surface of the fan.

[0060] When both α and β are negative, in the top view of the fan (as Figure 14 shown), when the fan rotates counterclockwise, it is a forward rotation, and the air enters the air duct from the air inlet surface of the fan; when rotating in reverse, the air leaves the air duct through the air inlet surface of the fan.

[0061] When the fan rotates forward, the rotational speed is 800 - 1500 rpm, and the centrifugal force generated by the fan blade assembly is the main driving force. Combining with the axial lift, it drives the air flow to enter the air duct structure from the air inlet 15 of the fan and is output through the outlet system.

[0062] When the fan rotates in reverse, the rotational speed is 500 - 1200 rpm, and the sum of the static pressure provided by the back plate and the static pressure of the system impedance is greater than the static pressure of the fan itself, resulting in the reverse output of the air flow from the air inlet 15 of the fan.

[0063] In a possible implementation, the preset static pressure difference is: P_fan < P_air duct + P_back plate, where P is the static pressure.

[0064] In a possible implementation, the annular flow channel 16 of the flared and tapered structure helps to increase the speed and efficiency of the incoming air flow, and the annular flow channel 16 of the flared and tapered structure provides about 10% to 16% of the flow rate of the reversed air outlet. Among them, the distance from the highest surface of the reinforcement ring 12 on the fan blade assembly to the air inlet surface is preferably 8.3 mm, which is convenient for realizing the reversed air outlet.

[0065] As Figures 11-12 shown, when the flared structure exists, the air inlet surface of the air duct is the enclosed area formed by the top circular surface of the flared opening. At this time, the height of the air inlet of the air duct is the same as the height of the air inlet 15 of the fan. When the flared structure does not exist, the air inlet surface of the air duct is the enclosed circular surface formed by the highest inner ring at the air inlet of the air duct.

[0066] In a possible implementation, when the fan rotates forward, the centrifugal force generated by the fan blade assembly is the main driving force, combined with the axial lift to drive the air flow to enter the air duct structure from the air inlet 15 of the fan and output through the outlet system;

[0067] When the fan rotates in reverse, the sum of the static pressure provided by the back plate and the static pressure of the system impedance is greater than the static pressure of the fan itself, resulting in the reverse output of the air flow from the air inlet 15 of the fan.

[0068] In a possible implementation, the back plate is arranged at the top of the air duct bracket 1.

[0069] The back plate is installed on the top of the air duct bracket 1, and the height difference spacing h between the shadow surfaces between the air inlet 14 of the back plate and the air inlet 15 of the fan is set to 15 - 50 mm, preferably 28.9 ± 0.5 mm, to form a preset static pressure difference. The sum of the static pressure provided by the back plate and the static pressure of the system impedance is greater than the static pressure of the fan itself, thereby promoting the reverse output of the air flow.

[0070] The fan blade assembly adopts swept-back fan blades (which can be replaced by forward-swept fan blades), the chord length of the fan blades is preferably 65 mm, and the inclination angle is set to 38°. The air guiding structure 11 is selected in the form of a rounded corner, and the radius of the rounded corner is 12% of the chord length of the fan blade (i.e., 7.8 mm), and this size range can effectively eliminate the air flow separation phenomenon at the blade tip.

[0071] When the fan rotates forward: control the motor to drive the fan blades to rotate at a speed of 1200 rpm. At this time, the centrifugal force generated by the fan blades is the main driving force, combined with the axial lift to suck the air flow from the air inlet 15 of the fan. The air flow forms a laminar flow state after being rectified by the guide plate 10 and is finally output through the six air outlets 101 simultaneously.

[0072] When reverse air outlet is required: control the motor to rotate in reverse at 900 rpm. At this time, the sum of the static pressure generated by the back plate and the static pressure of the system impedance exceeds the static pressure of the fan itself, forcing the air flow to be output in reverse from the air inlet 15 of the fan.

[0073] Among them, the air guiding structure 11 can be replaced with an air guiding cover, the extension length of the cover body is 18% of the chord length of the fan blade, and the inclination angle of the fan blade is adjusted to 25°.

[0074] In a possible implementation manner, it further includes: a reinforcing ring 12, and the reinforcing ring 12 is arranged on the annular surface formed by the rim of the fan blade part.

[0075] The distance from the highest surface of the reinforcing ring 12 on the fan blade assembly to the air inlet surface is greater than 1 mm, providing additional stability

[0076] Such as Figure 13 As shown, taking the fan surface closest to the visual direction as the top surface and the farthest surface as the bottom surface.

[0077] Fan air inlet surface:

[0078] ① When there is a reinforcing ring 12 on the top surface of the fan, the surface enclosed by the outer ring of the reinforcing ring 12 is the fan air inlet surface;

[0079] ② When there is no reinforcing ring 12 on the top surface of the fan, the closed circular surface formed by passing through all the points on the top surface of the outer edges of the fan blades is the fan air inlet surface.

[0080] In a possible implementation manner, the radius of the rounded corner of the air guiding structure 11 is 10%-15% of the chord length of the fan blade, which is used to optimize the air flow separation characteristics.

[0081] The present invention also protects a fan, including a fan blade assembly; the fan further includes:

[0082] An air duct bracket 1 adaptively installed with the fan blade assembly, and the air guiding structure 11 at the bottom of the fan blade part is located between the fan blade part and the installation surface 17 of the air duct bracket.

[0083] When the connection port between the air duct bracket 1 and the fan blade assembly is set as an annular flow channel 16 with a flared and tapered structure, the fan air inlet surface and the air duct air inlet surface are at the same height;

[0084] When the connection port between the air duct bracket 1 and the fan blade assembly is set as an annular flow channel 16 with a non-flared and tapered structure, the height difference between the fan air inlet surface and the air duct air inlet surface > 1 mm;

[0085] In a possible implementation manner, the air guiding structure 11 has an air guiding function, and the connection with the fan presents as including a rounded corner structure, a chamfer structure or an air guiding cover. An arc-shaped flow guiding plate 10 is arranged inside the air duct bracket 1. The radius of curvature of the flow guiding plate 10 is tangent to the rotation trajectory of the fan blade, effectively suppressing air flow turbulence.

[0086] In a possible implementation, the air duct bracket 1 is provided with an outlet system, and the outlet system includes N air outlets 101 distributed at the bottom of the air duct bracket 1, where N≥1 and N is an integer.

[0087] In a possible implementation, an arc-shaped flow guide plate 10 is arranged inside the air duct bracket 1, and the arc-shaped flow guide plate 10 helps to further optimize the direction and speed of the air flow.

[0088] In this embodiment, the fan includes an air duct bracket 1, a fan blade assembly, an air duct structure, and an outlet system. The air duct bracket 1 is formed by aluminum alloy casting to form an annular flow channel 16, and the inlet section is designed as a flared and tapered structure. The fan blade assembly is connected to the output shaft of the brushless motor through a hub flange.

[0089] The outlet system is configured to:

[0090] When the fan blade part rotates forward, taking the centrifugal force generated by the fan blade part as the main driving force, combined with the axial lift to drive the air flow to enter the air duct inlet of the fan from the air inlet 15 of the fan, and output through the outlet system.

[0091] The fan further includes:

[0092] A back plate, installed directly above the fan blade part;

[0093] The back plate is configured to:

[0094] When the fan blade part rotates in reverse, a preset static pressure difference is formed around the fan blade part, so that the sum of the static pressure provided by the back plate and the static pressure of the system impedance is greater than the static pressure of the fan itself, resulting in the reverse output of the air flow from the air inlet 15 of the fan.

[0095] The air duct bracket 1 is further provided with an arc-shaped flow guide plate 10 for suppressing air flow turbulence and / or changing the air flow trajectory.

[0096] The back plate is installed on the top of the air duct bracket 1, and its back plate air outlet 13 can be tightly attached to the air duct bracket 1 through a snap structure. The distance h between the shaded surface of the back plate air inlet 14 and the air inlet 15 of the fan is set to 28.9 mm (tolerance ±0.5 mm), and this distance can form an optimal static pressure difference range (120 - 180 Pa) to achieve stable switching under forward and reverse rotation conditions. The outlet system includes six air outlets 101 evenly distributed at the bottom of the air duct bracket 1.

[0097] Description: The fan achieves efficient two-way air supply through the collaborative design of swept-back or forward-swept fan blades 9 and the air guiding structure 11. When rotating forward, the fan blades rotate at 800 - 1500 rpm. The centrifugal force and axial lift drive the air flow to enter the air duct from the back panel air inlet 14 through the fan air inlet 15. After being rectified by the arc-shaped deflector 10, the air is evenly distributed to six air outlets 101. The rounded corners / air guiding covers of the air guiding structure 11 inhibit air flow separation. When rotating in reverse, the fan blades rotate in the reverse direction at 500 - 1200 rpm. The static pressure difference (120 - 180 Pa) formed by the distance h (15 - 50 mm, preferably 28.9 ± 0.5 mm) between the shaded surface of the back panel air inlet 14 and the fan air inlet 15 forces the air flow to be output in the reverse direction. The reinforcement ring 12 enhances the rigidity of the fan blades, and the outlet system equalizes the air pressure, achieving a two-way function with a forward air volume of 850 m 3 / h, 72% of the forward value in the reverse direction. The turbulence intensity ≤ 8%, and the energy efficiency is improved by 27%. It is applicable to ventilation and reverse cleaning scenarios.

[0098] The above are only the preferred embodiments of the present invention, and do not limit the patent scope of the present invention accordingly. Any equivalent structure or equivalent process transformation made by using the content of the specification and drawings of the present invention, or directly or indirectly applied in other related technical fields, shall be similarly included in the patent protection scope of the present invention.

Claims

1. A fan blade assembly, characterized in that: Comprising: A blade part and a wind guiding structure arranged at the bottom of the blade part, the blade part being a backward-swept blade or a forward-swept blade, and the wind guiding structure being a rounded-corner structure, a chamfer structure or a wind guiding cover; Along the rotation direction when the blade part rotates forward, the installation angle and the inclination angle of the blade part are configured to: When the blade assembly is adaptively installed on the air duct bracket and a back plate is installed directly above the blade part, it can enable the blade part to achieve an air outlet function when rotating in reverse; wherein, the wind guiding structure at the bottom of the blade part is located between the installation surface of the blade part and the air duct bracket, and the blade part achieves an air inlet function when rotating forward.

2. A fan blade assembly according to claim 1, characterized in that: The range of the installation angle of the blade part is from +15° to +45°, or from -15° to -45°, and the range of the inclination angle is from +25° to +50°, or from -25° to -50°.

3. A fan blade assembly according to claim 1, characterized in that: When a back plate is installed directly above the blade part, the distance h between the blade part and the back plate is 15 - 50 mm, so that when the blade part rotates in reverse, a preset static pressure difference is formed around the blade part.

4. A fan blade assembly according to claim 3, characterized in that: The distance h between the blade part and the back plate is 28.9 ± 0.5 mm.

5. A fan blade assembly according to claim 3, characterized in that: The preset static pressure difference is: P_blade < P_air duct + P_back plate, where P is the static pressure.

6. A fan blade assembly according to claim 1, characterized in that: The radius of the rounded corner of the wind guiding structure is 10% - 15% of the chord length of the blade, which is used to optimize the air flow separation characteristics.

7. The fan blade assembly according to claim 1, characterized in that: The top of the blade part is the air inlet surface of the fan, which is different from the air inlet surface of the air duct of the fan, and the height difference between the air inlet surface of the fan and the air inlet surface of the air duct is less than the axial thickness of the blade part.

8. The fan blade assembly according to claim 1, characterized in that: Further comprising: A reinforcement ring, which is arranged on the annular surface formed by the rim of the blade part.

9. A fan blade assembly according to claim 8, characterized in that: When the reinforcement ring is arranged at the upper port of the annular surface, the plane where the upper end surface of the reinforcement ring is located is the air inlet surface of the fan.

10. A fan, characterized in that: Comprising a blade assembly according to any one of claims 1 - 9; the fan further comprises: An air duct bracket adaptively installed with the blade assembly, and the wind guiding structure at the bottom of the blade part is located between the installation surface of the blade part and the air duct bracket.

11. The fan according to claim 10, characterized in that: The air duct bracket is provided with an outlet system, and the outlet system includes N air outlets distributed at the bottom of the air duct bracket, where N ≥ 1 and N is an integer; The outlet system is configured to: When the blade part rotates forward, taking the centrifugal force generated by the blade part as the main driving force, combined with the axial lift to drive the air flow to enter the air inlet of the fan from the air inlet of the air duct of the fan and output through the outlet system.

12. The fan according to claim 10 or 11, characterized in that: The fan further comprises: A back plate, installed directly above the blade part; The back plate is configured to: When the blade part rotates in reverse, a preset static pressure difference is formed around the blade part, so that the sum of the static pressure provided by the back plate and the static pressure of the system impedance is greater than the static pressure of the fan itself, resulting in the air flow being output in the reverse direction from the air inlet of the fan.

13. The fan according to claim 12, characterized in that: The air duct bracket is further provided with an arc-shaped flow deflector for suppressing air flow turbulence and / or changing the air flow trajectory.

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