Low-noise cooling fan

Abstract

The utility model relates to a low-noise cooling fan, which solves the problems in the prior art, adopts the technical scheme that the low-noise cooling fan comprises a hub and a plurality of fan blades arranged on the hub, and is characterized in that the fan blades are distributed in a central symmetry radial shape and are in a vortex shape; the size of an air inlet of a flow guide channel between every two adjacent fan blades in the circumferential direction is smaller than that of an air outlet of the flow guide channel in the circumferential direction, and the windward side of the hub is a retroverted flaring horn face. The hub has the advantages that the plane windward side of an existing hub is changed into the backward-tilting flaring horn face, meanwhile, the vortex-shaped blades are matched, the windward side in the shape of the backward-tilting flaring horn face is adopted, vibration generated by vortex can be reduced when airflow is guided, noise generated by vibration can be reduced, and meanwhile the effect of reducing noise is achieved. The vortex-shaped fan blades can more smoothly guide air flow to flow centrifugally, impact of the air flow on the blades is reduced, and noise generated by air flow impact and noise generated by blade vibration can be reduced.

Description

Technical Field

[0001] This utility model relates to the field of cooling fans, and in particular to a low-noise cooling fan. Background Technology

[0002] The noise problem of household water pumps is receiving increasing attention. The noise primarily originates from mechanical vibrations during pump operation, vibrations caused by the electromagnetic force of the motor, and aerodynamic noise generated by the high-speed rotation of the cooling fan. This noise not only affects the quiet and comfortable home environment, but prolonged exposure to high-decibel noise can also negatively impact physical and mental health.

[0003] People are constantly improving household water pumps to reduce operating noise. For example, the utility model patent with publication number CN204677494U, entitled "A Flexible Plastic Fan for an Electric Motor," uses flexible fan blades to reduce aerodynamic noise. Specifically, the flexible fan blades bend during rotation, becoming a backward-curved fan. The deformed fan blades do not have sharp corners, thus avoiding the whistling sound that occurs when the sharp corners of a metal fan cut through the air, thereby reducing noise. However, flexible fan blades are unstable and vibrate significantly during operation, causing more turbulence at the tail of the blades. This not only affects the stability of the fan's operation but also easily generates new noise. Therefore, existing fans still have a serious noise problem. Summary of the Invention

[0004] The purpose of this invention is to solve the aforementioned problems in the prior art by providing a low-noise cooling fan. It changes the existing hub's flat windward surface to a backward-inclined flared horn surface, and incorporates vortex-shaped blades. When the fan is working, under the action of centrifugal force and the backward-inclined flared horn surface, the airflow drawn into the fan axially flows centrifugally along the guide channel. Simultaneously, it guides the airflow from front to back along the windward surface of the hub to the leeward side of the hub, allowing the airflow to flow centrifugally while simultaneously flowing from front to back. The backward-inclined flared horn shape of the windward surface reduces vortex-induced vibration when guiding the airflow, thereby reducing noise generated by vibration. Furthermore, the vortex-shaped blades guide the centrifugal flow of the airflow more smoothly, reducing the impact of the airflow on the blades, which further helps to reduce noise generated by airflow impact and blade vibration.

[0005] The above-mentioned technical objective of this utility model is mainly achieved through the following technical solution: a low-noise cooling fan, comprising a hub and several fan blades disposed on the hub, characterized in that the several fan blades are centrally symmetrically distributed in a radial pattern, the fan blades are vortex-shaped, the circumferential dimension of the air inlet of the guide channel between adjacent fan blades is smaller than the circumferential dimension of the air outlet of the guide channel, and the windward surface of the hub is a backward-inclined flared horn surface. By changing the existing flat windward surface of the hub to a backward-inclined flared horn surface, and simultaneously using vortex-shaped blades, the windward surface with a backward-inclined flared horn shape can reduce the vibration caused by vortices when guiding airflow, thereby reducing the noise generated by vibration. At the same time, the vortex-shaped fan blades can more smoothly guide the centrifugal flow of airflow, reducing the impact of airflow on the blades, which in turn helps to reduce the noise generated by airflow impact and blade vibration. When the fan is working, under the action of centrifugal force and the backward-curved flared surface, the airflow drawn into the fan from the axial center flows centrifugally along the guide channel defined by the vortex-shaped blades. At the same time, along the windward side of the hub, which is also in the shape of a backward-curved flared surface, the airflow is guided from front to back. That is, the airflow in front of the windward side is guided to the rear of the leeward side of the hub. This makes the airflow flow centrifugally and from front to back at the same time, reducing the vibration generated by vortices. It can also reduce the impact noise and vibration noise generated by the airflow colliding with the hub and blades, thereby effectively reducing the noise generated when the fan is working.

[0006] As a further improvement and supplement to the above technical solution, the present invention adopts the following technical measures:

[0007] Preferably, the radial radius of the fan blade is larger than the radius of the hub, and the outer edge of the hub smoothly transitions to the two sides of the fan blade with an arc. A flow channel is formed between the outer edge of the hub and the outer end of the fan blade, which is used to guide air axially from the air-guiding surface of the hub to the leeward side of the hub. The smooth transition of the outer edge of the hub to the two sides of the fan blade avoids sharp corners and edges between the hub and the fan blade, preventing collisions between sharp corners and edges and the airflow, reducing airflow outlet impact losses, improving fan efficiency, and facilitating smoother airflow, thus reducing noise generated during fan operation. Furthermore, the smooth transition of the outer edge of the hub to the two sides of the fan blade also enhances connection reliability and avoids stress concentration. The flow channel allows the airflow entering the fan to flow from front to back, facilitating axial heat dissipation.

[0008] Preferably, the outer edge of the hub is located at 3 / 8 to 5 / 8 of the fan blade length, and the area of ​​the flow passage is 60.9 to 85.9% of the area of ​​the guide channel. The arrangement and size of the flow passage facilitate axial airflow into the fan and centrifugal flow along the windward side of the hub, while simultaneously driving the overall airflow from front to back. Furthermore, it helps ensure the airflow direction and axial flow volume, and also helps maintain the strength of the outer end of the fan blade, thereby ensuring the reliability and service life of the low-noise cooling fan.

[0009] Preferably, the hub includes an air guide plate and a bearing seat located in the center of the air guide plate. The hub and the bearing seat are an integral structure, and the axial dimension of the bearing seat is larger than the axial dimension of the hub. The bearing seat has an axially penetrating shaft hole for assembly. Typically, the hub and fan blades are integrally formed, and the axial dimension of the bearing seat is larger than the axial dimension of the hub. In other words, the thickness of the bearing seat is greater than the thickness of the hub. This ensures that after the hub is assembled onto the rotating shaft, the bearing seat has sufficient mating surface to effectively withstand torsional forces, promoting efficient fan operation, reducing energy consumption, and improving the strength of the bearing seat (i.e., the overall strength of the hub and fan). This also helps ensure the reliability and service life of the low-noise cooling fan.

[0010] Preferably, the air guide plate has a windward side and a leeward side. The windward side is a frustum-shaped surface, a spherical cap surface, or a parabolic surface, facing the fan blade. The working surface of the fan blade is perpendicular to the windward side, and the working surface of the fan blade is a radially extending, circumferentially curved vortex arc surface. Provided that the windward side provides front-to-back guidance, it can also be a smooth curved surface of other shapes or an irregular smooth curved surface.

[0011] Preferably, the fan blades mate with the windward side of the air guide plate, with the bottom end of the fan blades coplanar with the leeward side of the air guide plate, and the top end of the fan blades protruding outward from the windward side of the air guide plate. This helps ensure that the working surface of the fan blades has sufficient area, thereby ensuring the airflow efficiency of the low-noise cooling fan, and consequently, the heat dissipation efficiency of the low-noise cooling fan.

[0012] Preferably, the air outlet end of the fan blade is provided with a reinforcing portion that protrudes axially outward in the direction away from the leeward side of the air guide plate. The reinforcing portion is used to increase the working area of ​​the air outlet end of the fan blade. The addition of the reinforcing portion helps to increase the airflow efficiency when the fan blade rotates, thereby increasing the air volume and improving the heat dissipation efficiency of the low-noise cooling fan.

[0013] Preferably, the outer diameter of the hub is D1, the diameter of the circumcircle of the outer edge of the fan blade is D2, the diameter of the incircle of the inner edge of the reinforcement is D3, the height of the air inlet end of the fan blade is b1, the height of the air outlet end of the reinforcement is b2, the mounting angle of the air inlet end of the fan blade is α1, the mounting angle of the air outlet end of the fan blade is α2, the number of fan blades is N, and the geometric dimensions of the cooling fan are F, where F = [D1, D2, b1, b2, b3, α1, α2, N], where...

[0014] b1 + b2 ≤ b3;

[0015] b2×D2≤b3×D1;

[0016] D3 = (0.8 ~ 0.98)·D2;

[0017] D1 = (0.5 ~ 0.8)·D2;

[0018] α1 = 30°~40°;

[0019] α2 = 25°~60°;

[0020] N≈(4~6)sinα2 / (1-D1 / D2).

[0021] The specific performance of a low-noise cooling fan is determined by its geometric dimensions F, which in turn are determined by parameters such as D1, D2, b1, b2, b3, α1, α2, and N. Optimal fan geometry and dimensions are obtained by limiting the values ​​of these parameters. Limiting the installation angle of the fan blades' inlet end to α1 and the outlet end to α2 helps reduce airflow losses due to impact and separation during pressurization. Too few blades N can lead to gas turbulence between blades, low efficiency, and poor rigidity; conversely, too many blades N reduce the effective airflow area, increase friction loss, and decrease efficiency. Therefore, limiting the number of blades N to approximately (4~6)sinα2 / (1-D1 / D2) ensures fan strength, provides sufficient flow channel area for smooth airflow during centrifugal motion, reduces friction loss and noise, and also ensures fan efficiency.

[0022] Preferably, the outer edge of the fan blade is provided with a fixing ring, and the outer edge of each fan blade is fixed to the fixing ring. The top surface of the fixing ring is located on the extension surface of the air guide surface of the air guide plate, and the bottom surface of the fixing ring is coplanar with the bottom surface of the fan blade, and the bottom surface of the fixing ring is located on the extension surface of the leeward side of the air guide plate. The air inlet and outlet ends of the fan blades are both arc-shaped ends. The fixing ring is used to fix the outer end of the fan blade, which not only helps to enhance the strength of the fan blade, improve the reliability and service life of the fan, but also helps to reduce the vibration generated during the operation of the fan, further helping to reduce noise. Defining the top and bottom surfaces of the fixing ring helps to determine a suitable thickness for the fixing ring, which not only increases the strength of the fan blade, but also helps to rationally consume raw materials, which is conducive to energy conservation and environmental protection. At the same time, defining the position of the top and bottom surfaces of the fixing ring helps to reduce the impact of the fixing ring on the airflow, ensuring efficient airflow, which helps to ensure the working efficiency of the fan and reduce noise.

[0023] Preferably, the low-noise cooling fan also includes a fan shroud, with the hub and blades disposed within the inner cavity of the shroud. The fan shroud is frustoconical in shape, with the air-guiding surface of the hub facing the smaller end of the fan shroud and the leeward surface facing the larger end of the fan shroud. The arrangement and shape of the fan shroud facilitate airflow convergence, reduce escape, and increase the axial wind speed generated by the fan. The frustoconical shape of the fan shroud primarily ensures that the inner surface of the fan shroud is conical. When the outer wall of the fan shroud is parallel to the inner wall, it helps to reduce the consumption of raw materials for the fan shroud. Therefore, when the fan shroud is cylindrical, or when the inner wall of the fan shroud is frustoconical and the outer wall is cylindrical, it also falls within the scope of protection claimed in this technical solution.

[0024] The beneficial effects of this utility model are as follows: 1. By changing the existing flat windward surface of the hub to a backward-inclined flared horn surface, and simultaneously using vortex-shaped blades, the backward-inclined flared horn surface shape of the windward surface reduces vortex vibration during airflow guidance, thereby reducing noise generated by vibration. 2. The vortex-shaped blades can more smoothly guide the centrifugal flow of airflow, reducing the impact of airflow on the blades, thus helping to reduce noise generated by airflow impact and blade vibration. 3. The outer edge of the hub transitions to the two sides of the blades with a rounded arc, avoiding sharp corners and edges between the hub and the blades. This helps to prevent sharp corners and edges from colliding with the airflow, reducing airflow outlet impact loss, improving fan efficiency, and facilitating smoother airflow, thereby reducing noise generated during fan operation and enhancing connection reliability, avoiding stress concentration. 4. The design of the flow channel allows the airflow entering the fan to flow from front to back, which is beneficial for axial heat dissipation. The area relationship between the flow channel and the guide channel helps ensure the airflow direction and axial flow volume, and also helps ensure the strength of the outer end of the fan blades, thus helping to ensure the reliability and service life of the low-noise cooling fan. 5. The reinforcement section located at the air outlet end of the fan blades helps increase the airflow efficiency when the fan blades rotate, thereby increasing the airflow volume and improving the cooling efficiency of the low-noise cooling fan. 6. The relationship between the parameters of the cooling fan's geometric dimensions F helps ensure fan strength, ensures sufficient guide channel area for smooth airflow during centrifugal motion, reduces friction loss, lowers noise, and also helps ensure fan efficiency. 7. The setting of the fixing ring helps increase the strength of the outer end of the fan blades, reduces vibration, and lowers noise. 8. The rounded transition edges at the air inlet and outlet ends of the fan blades help reduce friction loss and lower noise. Attached Figure Description

[0025] Figure 1 This is a schematic diagram of the structure of this utility model.

[0026] Figure 2 yes Figure 1 A schematic diagram of a rear-view structure.

[0027] Figure 3 yes Figure 1 A schematic diagram of a frontal structure.

[0028] Figure 4 yes Figure 3 Schematic diagram of the cross-sectional structure in the middle GG direction.

[0029] Figure 5 This is a partial structural diagram of a wheel hub and fan blades involved in this utility model.

[0030] Figure 6 This is a schematic diagram of a structure of the present invention, in which a fan cover is provided around the hub and the fan blades.

[0031] In the diagram: 1. Fan blade; 2. Airflow channel; 3. Flow channel; 4. Windward side; 5. Leeward side; 6. Air guide plate; 7. Shaft seat; 8. Shaft hole; 9. Reinforcing part; 10. Fixing ring; 11. Top surface; 12. Bottom surface; 13. Fan cover. Detailed Implementation

[0032] The technical solution of this utility model will be further described in detail below through embodiments and with reference to the accompanying drawings. In this document, "front" refers to the direction corresponding to the windward side of the wheel hub, and "rear" refers to the direction corresponding to the leeward side of the wheel hub.

[0033] Example: Figures 1-5 As shown, a low-noise cooling fan includes a hub and several fan blades 1 disposed on the hub.

[0034] The difference between this technical solution and the prior art is that: several of the fan blades 1 are distributed in a centrally symmetrical radial pattern, the fan blades 1 are vortex-shaped, the circumferential dimension of the air inlet of the guide channel 2 between adjacent fan blades 1 is smaller than the circumferential dimension of the air outlet of the guide channel 2, and the windward surface 4 of the hub is a rearward-inclined flared horn surface.

[0035] In this technical solution, the existing flat windward surface 4 of the hub is changed to a backward-inclined flared horn surface. At the same time, it is combined with vortex-shaped blades. The windward surface 4 with the backward-inclined flared horn shape can reduce the vibration caused by vortices when guiding the airflow, thereby reducing the noise generated by vibration. At the same time, the vortex-shaped blades 1 can more smoothly guide the centrifugal flow of airflow, reduce the impact of airflow on the blades, and thus help reduce the noise generated by airflow impact and blade vibration.

[0036] When the low-noise cooling fan involved in this technical solution is working, the hub and blades rotate in the same direction, generating centrifugal force. Under the action of centrifugal force and the windward surface 4 of the hub's backward-inclined flared horn shape, the airflow drawn into the fan from the axial center flows centrifugally along the guide channel 2 defined by the vortex-shaped blades, while simultaneously flowing along the backward-inclined windward surface 4, guiding the airflow from front to back (that is, guiding the airflow in front of the windward surface 4 to the rear of the hub's leeward surface 5). This centrifugal flow, while flowing from front to back, helps reduce the vibration generated by vortices, and also reduces the impact and vibration noise generated by the airflow colliding with the hub and blades, thereby effectively reducing the noise generated when the fan is working.

[0037] Next, the above plan will be further explained:

[0038] In practical applications, the radial radius of the blade 1 is greater than the radius of the hub. The outer edge of the hub transitions to the two sides of the blade 1 in an arc. A flow passage 3 is formed between the outer edge of the hub and the outer end of the blade 1. The flow passage 3 is used to guide air axially from the windward side of the hub to the leeward side 5 of the hub.

[0039] In this technical solution, the outer edge of the hub transitions smoothly with the two sides of the fan blade 1, avoiding sharp corners and edges between the hub and the fan blade 1. This helps prevent collisions between sharp corners and edges and the airflow, reducing airflow outlet impact losses. This not only improves fan efficiency but also facilitates smoother airflow, thus reducing noise generated during fan operation. Furthermore, the smooth transition of the outer edge of the hub with the two sides of the fan blade 1 enhances connection reliability and prevents stress concentration. The flow channel 3 allows the airflow entering the fan to flow from front to back, facilitating axial heat dissipation.

[0040] In practical applications, the outer edge of the hub is located at 3 / 8 to 5 / 8 of the length of the fan blade 1 (typically the length along the curvature of the fan blade 1), and the area of ​​the flow passage 3 is 60.9% to 85.9% of the area of ​​the guide channel 2. For example, it is feasible for the outer edge of the hub to be located at 1 / 2, 3 / 4, or other values ​​within the range of the length of the fan blade 1. Similarly, it is feasible for the area of ​​the flow passage 3 to be 65%, 70%, 75%, 80%, or other values ​​within the range of the area of ​​the guide channel 2.

[0041] In this technical solution, the arrangement and size of the flow channel 3 are conducive to the axial flow of air into the fan and the centrifugal flow along the windward surface 4 of the hub, while driving the overall airflow from front to back. Furthermore, it helps to ensure the airflow direction and axial flow volume, and also helps to ensure the strength of the outer end of the fan blade 1, thereby helping to ensure the reliability and service life of the low-noise cooling fan.

[0042] In practical applications, the hub includes an air guide plate 6 and a bearing 7 located in the middle of the air guide plate 6. The hub and the bearing 7 are an integral structure. The axial dimension of the bearing 7 is greater than the axial dimension of the hub. The bearing 7 has an axially penetrating shaft hole 8 for assembly.

[0043] Typically, to facilitate production, processing, and assembly, and to ensure the stability and lifespan of the fan, the hub and fan blades 1 are integrally formed. The axial dimension of the bearing seat 7 is larger than that of the hub, meaning the thickness of the bearing seat 7 is greater than that of the hub. This ensures that after the hub is assembled onto the rotating shaft, the bearing seat 7 has sufficient mating surface to effectively withstand torsional forces, which is beneficial for the fan to work efficiently, reduce energy consumption, and improve the strength of the bearing seat 7 (i.e., the overall strength of the hub and fan). This also helps to ensure the reliability and lifespan of the low-noise cooling fan.

[0044] In practical applications, the wind guide plate 6 has a windward surface 4 and a leeward surface 5. The windward surface 4 is a frustum, a spherical cap, or a parabolic surface. The windward surface 4 faces the fan blade 1. The working surface of the fan blade 1 is perpendicular to the windward surface 4. The working surface of the fan blade 1 is a radially extended and circumferentially curved vortex arc surface.

[0045] In practical applications, provided that the windward surface 4 is guided from front to back, it can also be a smooth curved surface of other shapes or an irregular smooth curved surface.

[0046] In practical applications, in order to ensure that the working surface of the fan blade 1 has a sufficient area, thereby ensuring the wind power efficiency of the low-noise cooling fan and thus the heat dissipation efficiency of the low-noise cooling fan, the fan blade 1 is matched with the windward surface 4 of the air guide plate 6, the bottom end of the fan blade 1 is coplanar with the leeward surface 5 of the air guide plate 6, and the top end of the fan blade 1 protrudes outward from the windward surface 4 of the air guide plate 6.

[0047] In practical applications, the air outlet end of the fan blade 1 is provided with an axially protruding reinforcing part 9 that is away from the leeward surface 5 of the air guide plate 6. The reinforcing part 9 is used to increase the working area of ​​the air outlet end of the fan blade 1.

[0048] In this technical solution, the reinforcement 9 is designed to increase the airflow efficiency when the fan blades rotate, thereby increasing the air volume and improving the heat dissipation efficiency of the low-noise cooling fan.

[0049] In practical applications, the outer diameter of the hub is D1, the diameter of the circumcircle of the outer edge of the fan blade 1 is D2, the diameter of the incircle of the inner edge of the reinforcing part 9 is D3, the height of the air inlet end of the fan blade 1 is b1, the height of the air outlet end of the reinforcing part 9 is b2, the mounting angle of the air inlet end of the fan blade 1 is α1, the mounting angle of the air outlet end of the fan blade 1 is α2, the number of fan blades 1 is N, and the geometric dimensions of the cooling fan are F, where F = [D1, D2, b1, b2, b3, α1, α2, N], where...

[0050] b1 + b2 ≤ b3;

[0051] b2×D2≤b3×D1;

[0052] D3 = (0.8~0.98)·D2 (For example, selecting 0.85, 0.87, 0.9, 0.95 or other values ​​within the range of 0.8~0.98 are all feasible solutions);

[0053] D1 = (0.5~0.8)·D2 (For example, selecting 0.52, 0.6, 0.65, 0.7 or other values ​​within the range of 0.5~0.8 are all feasible solutions);

[0054] α1 = 30° to 40° (e.g., α1 = 32°, 35°, 39° or other degrees within the range are all feasible options);

[0055] α2 = 25° to 60° (e.g., α2 = 30°, 35°, 47°, 50° or other degrees within the range are all feasible options);

[0056] N≈(4~6)sinα2 / (1-D1 / D2) (For example, selecting 4.5, 5, 5.5 or other values ​​within the range of 4~6 are all feasible solutions).

[0057] In this technical solution, the specific performance of the low-noise cooling fan is determined by the geometric dimension F, which is in turn determined by parameters such as D1, D2, b1, b2, b3, α1, α2, and N. The optimal fan geometry and dimensions are obtained by limiting the values ​​of parameters such as D1, D2, b1, b2, b3, α1, α2, and N.

[0058] In this technical solution, limiting the installation angle of the air inlet end of the fan blade 1 to α1 and the installation angle of the air outlet end of the fan blade 1 to α2 helps to reduce the loss of airflow due to impact and separation during the pressurization process.

[0059] In this technical solution, too few blades N can easily lead to problems such as gas turbulence between blades, low efficiency, and poor rigidity; conversely, too many blades N will reduce the effective air intake area, increase friction loss, and lead to a decrease in efficiency. Therefore, limiting the number of blades N to the range of (4~6)sinα2 / (1-D1 / D2) is beneficial for ensuring fan strength and ensuring that the airflow has sufficient guide channel area 2 for smooth flow during centrifugal motion, reducing friction loss and thus ensuring fan efficiency.

[0060] In practical applications, the outer edge of the fan blade 1 is provided with a fixing ring 10, and the outer edge of each fan blade 1 is fixed to the fixing ring 10. The top surface 11 of the fixing ring 10 is located on the extension surface of the air guide surface of the air guide plate 6. The bottom surface 12 of the fixing ring 10 is coplanar with the bottom surface 12 of the fan blade 1, and the bottom surface 12 of the fixing ring 10 is located on the extension surface of the leeward side 5 of the air guide plate 6. The air inlet end and the air outlet end of the fan blade 1 are both arc ends.

[0061] In this technical solution, the fixing ring 10 is used to fix the outer end of the fan blade 1, which not only helps to enhance the strength of the fan blade 1 and improve the reliability and service life of the fan, but also helps to reduce the vibration generated when the fan is working, and further helps to reduce noise.

[0062] In this technical solution, defining the top surface 11 and bottom surface 12 of the fixing ring 10 helps to determine a suitable thickness for the fixing ring 10, which not only increases the strength of the fan blade 1, but also helps to rationally consume raw materials and is conducive to energy conservation and environmental protection. At the same time, defining the position of the top surface 11 and bottom surface 12 of the fixing ring 10 helps to reduce the impact of the fixing ring 10 on airflow, ensuring efficient airflow, which helps to ensure the working efficiency of the fan and reduce noise.

[0063] In practical applications, the low-noise cooling fan also includes a fan shroud 13. The hub and blades 1 are disposed within the inner cavity of the fan shroud 13. The fan shroud 13 is frustoconical in shape, with the air guiding surface of the hub facing the smaller opening of the fan shroud 13 and the leeward surface 5 of the hub facing the larger opening of the fan shroud 13. The arrangement and shape of the fan shroud 13 facilitate airflow convergence, reduce escape, and increase the axial wind speed generated by the fan.

[0064] In this technical solution, the fan shroud 13 is shaped like a frustum, primarily to ensure that the inner surface of the fan shroud 13 is conical. When the outer wall of the fan shroud 13 is parallel to the inner wall, it helps to reduce the consumption of raw materials for the fan shroud 13. Therefore, when the fan shroud 13 is cylindrical, or when the inner wall of the fan shroud 13 is frustum-shaped and the outer wall is cylindrical, it also falls within the scope of protection claimed in this technical solution.

[0065] The above description is merely a preferred embodiment of the present utility model and is not intended to limit the present utility model. Various modifications and variations can be made to the above embodiments. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present utility model should be included within the protection scope of the present utility model.

Claims

1. A low-noise cooling fan, comprising a hub and a plurality of fan blades (1) disposed on the hub, characterized in that... Several blades (1) are arranged in a centrally symmetrical radial pattern. The blades (1) are vortex-shaped. The circumferential dimension of the air inlet of the guide channel (2) between adjacent blades (1) is smaller than the circumferential dimension of the air outlet of the guide channel (2). The windward surface (4) of the hub is a rearward-inclined flared horn surface.

2. The low-noise cooling fan according to claim 1, characterized in that... The radial dimension of the blade (1) is greater than the radius of the hub. The outer edge of the hub is arc-shaped along the two sides of the blade (1). A flow passage (3) is formed between the outer edge of the hub and the outer end of the blade (1). The flow passage (3) is used to guide air axially from the windward side of the hub to the leeward side (5) of the hub.

3. The low-noise cooling fan according to claim 2, characterized in that... The outer edge of the hub is located at 3 / 8 to 5 / 8 of the length of the fan blade (1), and the area of ​​the flow passage (3) is 60.9 to 85.9% of the area of ​​the guide passage (2).

4. The low-noise cooling fan according to claim 2, characterized in that... The hub includes an air guide plate (6) and a bearing seat (7) located in the middle of the air guide plate (6). The hub and the bearing seat (7) are an integral structure. The axial dimension of the bearing seat (7) is greater than the axial dimension of the hub. The bearing seat (7) has an axially penetrating shaft hole (8) for assembly.

5. The low-noise cooling fan according to claim 4, characterized in that... The wind guide plate (6) has a windward surface (4) and a leeward surface (5). The windward surface (4) is a frustum, a spherical cap, or a parabola. The windward surface (4) faces the wind blade (1). The working surface of the wind blade (1) is perpendicular to the windward surface (4). The working surface of the wind blade (1) is a radially extended, circumferentially curved vortex arc surface.

6. The low-noise cooling fan according to claim 5, characterized in that... The fan blade (1) is matched with the windward side (4) of the air guide plate (6), the bottom end of the fan blade (1) is coplanar with the leeward side (5) of the air guide plate (6), and the top end of the fan blade (1) protrudes outward from the windward side (4) of the air guide plate (6).

7. The low-noise cooling fan according to claim 5, characterized in that... The air outlet end of the fan blade (1) is provided with an axially protruding reinforcement (9) in the direction away from the leeward side (5) of the air guide plate (6). The reinforcement (9) is used to increase the working area of ​​the air outlet end of the fan blade (1).

8. The low-noise cooling fan according to claim 7, characterized in that... The outer diameter of the hub is D1, the diameter of the circumscribed circle of the outer edge of the fan blade (1) is D2, the diameter of the inscribed circle of the inner edge of the reinforcing part (9) is D3, the height of the air inlet end of the fan blade (1) is b1, the height of the air outlet end of the reinforcing part (9) is b2, the installation angle of the air inlet end of the fan blade (1) is α1, the installation angle of the air outlet end of the fan blade (1) is α2, the number of fan blades (1) is N, and the geometric dimensions of the cooling fan are F, F=[D1, D2, b1, b2, b3, α1, α2, N], where, b1 + b2 ≤ b3; b2×D2≤b3×D1; D3 = (0.8 ~ 0.98)·D2; D1 = (0.5 ~ 0.8)·D2; α1＝30°～40°； α2＝25°～60°； N≈(4~6)sinα2 / (1-D1 / D2).

9. The low-noise cooling fan according to claim 8, characterized in that... The outer edge of the fan blade (1) is provided with a fixing ring (10), and the outer edge of each fan blade (1) is fixed on the fixing ring (10). The top surface (11) of the fixing ring (10) is located on the extension surface of the air guide surface of the air guide plate (6). The bottom surface (12) of the fixing ring (10) is coplanar with the bottom surface (12) of the fan blade (1), and the bottom surface (12) of the fixing ring (10) is located on the extension surface of the leeward side (5) of the air guide plate (6). The air inlet end and the air outlet end of the fan blade (1) are both arc ends.

10. The low-noise cooling fan according to any one of claims 1-9, characterized in that... It also includes a fan cover (13), the hub and the fan blade (1) are disposed in the inner cavity of the fan cover (13), the fan cover (13) is frustoconical, the air guiding surface of the hub faces the small opening end of the fan cover (13), and the leeward side (5) of the hub faces the large opening end of the fan cover (13).

Images