Centrifugal fan and electronic device

Abstract

A centrifugal fan and electronic equipment, the centrifugal fan (3) comprises: a housing (20), a rotating shaft (11) and an impeller (10), the housing (20) is provided with a second air inlet (201) and a second air outlet (202), the impeller (10) and the rotating shaft (11) are arranged in a cavity enclosed by the housing (20), the rotating shaft (11) is rotatably connected to the housing (20), the impeller (10) is connected to the rotating shaft (11), the impeller (10) comprises: a hub (200) and blades (100) fixedly connected to the hub (200), a blade (100) is arranged on the rotating shaft (11), a mean camber line (110) of an airfoil of the blade (100) is bent in the reverse direction of the rotating direction of the impeller, the mean camber line (110) of the airfoil of the blade (100) comprises a front edge end (1111) and a tail edge end (1121), the front edge end (1111) is located at the end, close to the rotating shaft (11), of the blade (100), the tail edge end (1121) is located at the end, away from the rotating shaft (11), of the blade (100), and the front edge end (1111) is located in front of the tail edge end (1121) in the rotating direction of the impeller (10). The centrifugal fan is designed in a sweepback C shape, noise generated when the impeller rotates and flowing loss of air can be reduced, increase of the air supply amount, reduction of the noise and improvement of the energy efficiency during operation of the centrifugal fan are facilitated, a soundproof box does not need to be additionally arranged outside the volute, and the overall size of the centrifugal fan is small.

Description

Centrifugal fan and electronic device

[0001] The present application claims priority to the Chinese patent application No. 202410978824.X, filed on July 19, 2024, and entitled "Centrifugal fan and electronic device", the content of which is incorporated herein by reference in its entirety. TECHNICAL FIELD

[0002] Embodiments of the present application relate to the fan technology field, in particular to a centrifugal fan and an electronic device. BACKGROUND

[0003] With the continuous improvement of the performance of electronic devices, the heat generated by electronic devices is increasing, which can be cooled by a fan. The working principle of the fan is to rotate the fan blade by the motor to generate airflow, and to generate forced convection in the electronic device to quickly remove the heat generated in the electronic device.

[0004] At present, consumers have higher demands for the thinness of electronic devices, which limits the design space of the fan, and the performance and thinness of the fan need to be improved. SUMMARY

[0005] Embodiments of the present application provide a centrifugal fan and an electronic device, which can balance the thin design and high performance of the centrifugal fan.

[0006] To achieve the above-mentioned purpose, the technical scheme adopted by the embodiments of the present application is as follows:

[0007] In a first aspect, the present application provides a centrifugal fan, comprising: a housing, a rotating shaft and an impeller, the housing is provided with an air inlet and an air outlet, the impeller and the rotating shaft are arranged in a cavity surrounded by the housing, the rotating shaft is rotatably connected with the housing, the impeller is connected with the rotating shaft, the impeller comprises: a hub and blades fixedly connected to the hub, wherein the middle camber line of the airfoil of the blade is curved in the opposite direction of the rotation direction of the impeller, the middle camber line of the airfoil of the blade comprises: a leading edge end and a trailing edge end, the leading edge end is located at one end of the blade close to the rotating shaft, the trailing edge end is located at one end of the blade away from the rotating shaft, and the leading edge end is located in front of the trailing edge end in the rotation direction of the impeller.

[0008] Therefore, this centrifugal fan features a swept-back C-shaped design, with the airfoil's mid-arc line forming a C-shaped segment. This design allows for applications with low exhaust resistance. The blades have lower resistance near the rotation axis, reducing the likelihood of vortex formation and facilitating smoother airflow between the blades. This allows air to adhere to the blade surface, reducing noise during impeller rotation and airflow loss. This design also increases airflow volume, reduces noise, and improves energy efficiency during centrifugal fan operation. It eliminates the need for an external soundproof enclosure to meet the requirement of low noise under high airflow conditions, resulting in a smaller overall size and making it suitable for use in thinner electronic devices.

[0009] In one optional implementation, the inlet angle of the blade is less than 60°. The inlet angle is the angle between the direction of the tangent along the mid-arc line of the blade's airfoil at the leading edge, pointing outwards from the impeller, and the opposite direction of rotation of the leading edge when the impeller rotates. This inlet angle is closer to the inlet angle when airflow reaches the blade's inlet, resulting in smoother airflow into the channel between the blades.

[0010] In one optional implementation, the blade's outlet angle is less than 90°. The outlet angle is the angle between the direction of the tangent along the mid-arc line of the blade's airfoil at the trailing edge, pointing outwards from the impeller, and the opposite direction of the impeller's rotation at the trailing edge. This causes the airflow channel of the blade to gradually widen, reducing pressure and thus increasing the air volume delivered.

[0011] In one optional implementation, the surface of the hub facing the air inlet includes a first region and a second region. The first region is connected to the rotation shaft, and the second region surrounds the first region. The second region includes opposing first and second sides. The first side of the second region is connected to the first region, and the second side of the second region is connected to the blade. The distance between the first side of the second region and the air inlet is less than the distance between the second side of the second region and the air inlet. The blade is divided into a first leading edge and a second leading edge, with the connection point between the blade and the hub serving as the dividing line. The first leading edge of the blade is closer to the air inlet, and the second leading edge is farther from the air inlet. Since the hub is located in the middle of the air inlet end of the blade airflow channel, it will block the second leading edge of the blade. This application divides the hub into two areas, and makes the second area of ​​the hub gradually move away from the air inlet. When the airflow flows into the housing through the air inlet, part of it directly enters the airflow channel of the blade, and part of it flows to the hub and is guided by the hub to the airflow channel. In this application, the second area of ​​the hub is tilted towards the blade, which can better guide the airflow into the airflow channel of the second leading edge of the blade, making the air intake at each position of the blade more uniform.

[0012] In one alternative implementation, the second region slopes radially from the first side toward the second side of the impeller in a direction away from the air inlet. Thus, the second region is an inclined surface, which better guides the airflow to the second leading edge of the impeller. This embodiment does not limit the inclination angle of the second region, as long as it guides the airflow to the air inlet end of the impeller. For example, the extension line of the second region may intersect with the impeller.

[0013] In one alternative implementation, in a direction away from the air inlet, the surface of the hub facing the air inlet is inclined towards the impeller along the radial direction of the impeller by the rotating shaft. Thus, the hub is inclined overall towards the impeller, meaning the impeller is conical, which better guides the airflow towards the impeller.

[0014] In one optional implementation, the leading edge of the blade includes a first leading edge and a second leading edge connected sequentially. The second end of the first leading edge and the first end of the second leading edge are both connected to the hub. The first end of the first leading edge is close to the air inlet, and the distance between the first end of the first leading edge and the rotation axis is greater than the distance between the second end of the first leading edge and the rotation axis. Thus, the leading edge of the blade is divided into two parts, and the first leading edge of the blade gradually approaches the hub. When airflow flows towards the first leading edge of the blade, the angle between the airflow direction and the first leading edge of the blade can approach 90°, allowing the airflow to better enter the airflow channel of the blade.

[0015] In one alternative implementation, the first leading edge is inclined radially toward the rotation axis of the impeller in a direction away from the air inlet. This further facilitates airflow into the airflow channel of the blade. The embodiments of this application do not limit the inclination angle of the first leading edge, as long as the angle between the airflow entering through the air inlet and the leading edge of the blade is more conducive to air entry. For example, the inclination angle of the first leading edge can be adjusted so that the angle between the airflow entering through the air inlet and the first leading edge is close to 90°.

[0016] In one alternative implementation, the second leading edge is parallel to the rotation axis. Thus, the second leading edge can be used to receive airflow guided by the hub, and by adjusting the hub's guiding angle, the airflow can be directed into the airflow channel of the blade's second leading edge.

[0017] In one alternative implementation, the distance between the first end of the second leading edge and the rotation axis is greater than the distance between the second end of the second leading edge and the rotation axis. This divides the blade leading edge into two parts, causing the second leading edge of the blade to gradually approach the hub. When the hub guides the airflow to the second leading edge of the blade, the angle between the airflow direction and the second leading edge of the blade can approach 90°, allowing the airflow to better enter the airflow channel of the blade.

[0018] In one optional implementation, the second leading edge is inclined radially toward the rotation axis of the impeller in a direction away from the air inlet. This further allows airflow to enter the airflow channel of the blade. The embodiments of this application do not limit the inclination angle of the second leading edge, as long as the angle between the airflow entering through the air inlet and the leading edge of the blade is more conducive to airflow entry. For example, the inclination angle of the second leading edge can be adjusted so that the angle between the airflow guided by the inclined surface of the hub (i.e., the inclined surface of the hub) and the first leading edge is close to 90°. In another optional implementation, the impeller includes multiple blades spaced circumferentially along the hub. An airflow channel is formed between adjacent blades, an air inlet is formed between the ends of adjacent blades near the rotation axis, and an air outlet is formed between the ends of adjacent blades away from the hub. The cross-section of the airflow channel gradually increases from the air inlet to the air outlet. As a result, the air velocity gradually increases when the air flows in the airflow channel, which helps to increase the air volume delivered by the centrifugal fan, resulting in lower noise and a larger air volume during operation.

[0019] In one optional implementation, the mid-curve of the airfoil of the blade is a second-order Bézier curve, and the leading edge and the trailing edge are the starting control point and the ending control point of the second-order Bézier curve, respectively.

[0020] After converting the coordinates in the impeller polar coordinate system to the blade rectangular coordinate system, the pole of the impeller polar coordinate system is located on the rotation axis of the hub, the polar angle of the leading edge in the impeller polar coordinate system is π / 2, the origin of the blade rectangular coordinate system is located at the leading edge, the horizontal axis of the blade rectangular coordinate system is the same as the polar axis of the impeller polar coordinate system, and the positive direction of the vertical axis of the blade rectangular coordinate system is the direction from the leading edge along the radial direction of the impeller to the outer side of the impeller. Therefore, the blade has less wind resistance at the end near the rotation axis, is less prone to vortex formation, allows air to flow more smoothly into the airflow channel, facilitates airflow adhering to the blade surface, reduces noise during impeller rotation and airflow loss, and benefits the centrifugal fan by increasing air volume, reducing noise, and improving energy efficiency. Furthermore, the airfoil of the blades closely matches the airflow field within the airflow channel, and the airfoil's strong resistance to adverse pressure gradients makes it difficult for the air flowing against the blade surface to separate from the blades during impeller rotation. This results in smoother airflow within the airflow channel, reducing impeller noise and airflow losses, and contributing to increased airflow, reduced noise, and improved energy efficiency during centrifugal fan operation. Moreover, the high degree of fit between the airfoil and the airflow field within the airflow channel results in good aerodynamic performance of the blades. The blades have high work efficiency on the air during rotation, leading to higher energy efficiency, higher air pressure at the outlet, and a higher airflow rate during centrifugal fan operation. The blade size can be adjusted using the formula of the second-order Bézier curve, facilitating the manufacture of centrifugal fans of different sizes with larger airflow rates and lower noise levels. In converting coordinates from the impeller's polar coordinate system to the blade's rectangular coordinate system, the conversion can be performed first to transform the impeller's polar coordinate system to the impeller's rectangular coordinate system. Then, translation methods can be used to convert the impeller's rectangular coordinate system to the blade's rectangular coordinate system. In the impeller's rectangular coordinate system, the origin is located on the rotation axis. The horizontal axis of the impeller's rectangular coordinate system coincides with the polar axis of the impeller's polar coordinate system. The positive direction of the vertical axis of the impeller's rectangular coordinate system is the direction from the rotation axis along the impeller's radial direction outwards. The units of the horizontal and vertical coordinates in the blade's rectangular coordinate system are the same; for example, both units can be meters, decimeters, centimeters, etc.

[0021] In one optional implementation, the housing includes: a sidewall, and a bottom plate and a top plate disposed opposite to each other. The sidewall is located between the top plate and the bottom plate, and the sidewall, the top plate, and the bottom plate together form the cavity. An air inlet is provided on the top plate, and an air outlet is provided on the sidewall. This allows the centrifugal fan to draw air in from the top plate and exhaust air from the sidewall, resulting in smoother airflow within the housing and a higher airflow velocity. This helps reduce noise during centrifugal fan operation and increases the air volume delivered by the centrifugal fan.

[0022] In one optional implementation, the rotating shaft is disposed between the top plate and the bottom plate. The centrifugal fan includes a crossbeam disposed in the air inlet and connected to the top plate. The crossbeam includes a connecting portion and a protrusion. The connecting portion connects the protrusion and the top plate, and the protrusion protrudes towards the bottom plate and is rotatably connected to the rotating shaft. Therefore, by providing a crossbeam on the top plate and a protrusion on the crossbeam, the rotating shaft can be limited, preventing it from wobbling up and down within the housing and enhancing the centrifugal fan's resistance to drop impacts.

[0023] In one optional implementation, the thickness of the protrusion is greater than the thickness of the connecting portion. Thus, by increasing the local thickness of the crossbeam to form a protrusion on the crossbeam, axial limiting of the rotating shaft can be achieved. In another optional implementation, a limiting member is provided on the side of the protrusion near the base plate, and the rotating shaft is rotatably connected to the limiting member. Therefore, by providing a limiting member on the protrusion, the circumferential limiting of the rotating shaft is enhanced, preventing lateral movement of the rotating shaft, improving impact resistance, and also helping to avoid shaking and abnormal noise.

[0024] In one alternative implementation, the protrusion and the connecting portion have the same thickness, and the protrusion is formed by bending the crossbeam. Thus, by bending the crossbeam, a protrusion can be formed on the crossbeam, reducing the weight of the crossbeam.

[0025] In one alternative implementation, an annular component is provided on the side of the protrusion facing the base plate, and the rotating shaft is rotatably connected to the annular component. Therefore, by providing the annular component on the protrusion, the circumferential restraint of the rotating shaft can be enhanced, preventing the rotating shaft from moving left and right, thus improving impact resistance and also helping to avoid shaking and abnormal noise.

[0026] In one optional implementation, the centrifugal fan further includes a central tube sleeved on the outside of the rotating shaft, the rotating shaft and the central tube being coaxially arranged, and the central tube and the base plate being integrally formed. Thus, by integrally forming the central tube and the base plate, the centrifugal fan's impact resistance is enhanced, and its drop protection performance can be further improved.

[0027] In one optional implementation, the central tube includes a first portion and a second portion, the first portion being disposed near the base plate, and the wall thickness of the first portion being greater than the wall thickness of the second portion. This increases the wall thickness of the portion of the central tube near the base plate, achieving localized reinforcement and further improving the centrifugal fan's resistance to drop impacts.

[0028] In one optional implementation, the centrifugal fan further includes: a motor housing, a motor, and a first sealing ring. The motor housing is connected to the rotating shaft, the hub is disposed on a first surface of the motor housing, the motor is disposed on a second surface of the motor housing, and the first sealing ring is disposed between the motor and the intermediate tube. Thus, by providing the first sealing ring, airflow can be prevented from entering the intermediate tube through the gap between the motor and the intermediate tube. The labyrinthine design inside the centrifugal fan facilitates dust and water resistance, improving the sealing performance of the centrifugal fan.

[0029] In one optional implementation, the centrifugal fan further includes a bearing and a second sealing ring. The bearing and the second sealing ring are disposed within the central tube and both are fitted onto the rotating shaft. The bearing is rotatably connected to the rotating shaft, and the second sealing ring is located on the side of the bearing near the top plate. Thus, by providing the second sealing ring, oil leakage from the bearing can be prevented, and airflow can be further prevented from entering the central tube, achieving dust and water resistance and improving the sealing performance of the centrifugal fan.

[0030] A second aspect of this application provides an electronic device including a heat-generating module and a centrifugal fan as described above, the centrifugal fan being used to dissipate heat from the heat-generating module. Thus, by employing the aforementioned centrifugal fan, the electronic device improves its heat dissipation performance and facilitates a thinner, lighter design. Attached Figure Description

[0031] Figure 1 is a schematic diagram of the structure of an electronic device provided in an embodiment of this application;

[0032] Figure 2 is a schematic diagram of a centrifugal fan provided in an embodiment of this application;

[0033] Figure 3 is a schematic diagram of the disassembled structure of the centrifugal fan in Figure 2;

[0034] Figure 4 is a top view of an impeller provided in an embodiment of this application;

[0035] Figure 5 is a cross-sectional view of AA in Figure 2;

[0036] Figure 6A is a schematic diagram of an impeller provided in an embodiment of this application;

[0037] Figure 6B is a cross-sectional view of BB in Figure 6A;

[0038] Figure 7 is a schematic diagram of the structure of a blade provided in an embodiment of this application;

[0039] Figure 8 is a schematic diagram of the mid-arc line of the airfoil of a blade provided in an embodiment of this application in the blade rectangular coordinate system;

[0040] Figure 9 is a structural schematic diagram of a top plate provided in an embodiment of this application;

[0041] Figure 10 is a schematic diagram of another top plate provided in an embodiment of this application;

[0042] Figure 11 is a schematic diagram of a middle tube provided in an embodiment of this application;

[0043] Figure 12 is a schematic diagram of a middle tube and a shell provided in an embodiment of this application. Detailed Implementation

[0044] To make the objectives, technical solutions, and advantages of this application clearer, the application will now be described in further detail with reference to the accompanying drawings.

[0045] In the following description, the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined with "first," "second," etc., may explicitly or implicitly include one or more of that feature. In the description of this application, unless otherwise stated, "a plurality of" means two or more.

[0046] Furthermore, in this application, directional terms such as "upper" and "lower" are defined relative to the orientation of the components shown in the accompanying drawings. It should be understood that these directional terms are relative concepts, used for relative description and clarification, and can change accordingly depending on the orientation of the components in the accompanying drawings.

[0047] This application provides an electronic device, which may be a mobile phone, tablet, laptop, smart home device, smart wearable device (e.g., smartwatch, smart bracelet, smart glasses, smart helmet), virtual reality (VR) electronic device, augmented reality (AR) electronic device, etc. The electronic device may also be a handheld device with wireless communication capabilities, a computing device or other processing device connected to a wireless modem, an in-vehicle device, an electronic device in a 5G network, or an electronic device in a future evolved public land mobile network (PLMN), etc. This application does not limit the scope of the application.

[0048] Figure 1 is a schematic diagram of an electronic device provided in an embodiment of this application.

[0049] As shown in Figure 1, in this embodiment of the application, the electronic device may include a housing 1, a heating module 2, and a centrifugal fan 3. The heating module 2 may be installed inside the housing 1, and the centrifugal fan 3 may be installed on the housing 1. The housing 1 may have a first air inlet 4 and a first air outlet 5. The centrifugal fan 3 may be used to generate airflow to drive the air at the heating module 2 to flow out of the housing 1 from the first air outlet 5. The air flowing out of the housing 1 from the first air outlet 5 may carry away the heat inside the housing 1 to improve the heat dissipation efficiency of the electronic device.

[0050] The heating module 2 can be any device that generates heat during operation and requires heat dissipation. For example, the heating module 2 can be a motherboard module, a service board module, a power supply module, etc. When the electronic device is running, the heating module 2 will generate heat, and the heat generated by the heating module 2 can be transferred to the air inside the casing 1.

[0051] In some embodiments, the electronic device may further include a first printed circuit board (PCB), on which the heating module 2 may be disposed. Both the heating module 2 and the first circuit board may be disposed within the cavity of the housing 1. For example, the heating module 2 may include, but is not limited to, a central processing unit (CPU), a graphics processing unit (GPU), etc.

[0052] This application does not limit the number of heating modules. The electronic device may include multiple heating modules 2 or just one, and the specific number and type of heating modules 2 can be selected and set according to requirements.

[0053] Figure 2 is a structural schematic diagram of a centrifugal fan provided in an embodiment of this application. Figure 3 is a disassembled structural schematic diagram of the centrifugal fan in Figure 2.

[0054] As shown in Figure 3, in this embodiment of the application, the centrifugal fan 3 may include a housing 20, an impeller 10, and a rotating shaft 11. The housing 20 may be installed on the outer casing 1 of the electronic device shown in Figure 1. The impeller 10 and the rotating shaft 11 may be installed inside the housing 20. The rotating shaft 11 is rotatably connected to the housing 20, and the impeller 10 is connected to the rotating shaft 11.

[0055] As shown in Figure 2, the housing 20 has a second air inlet 201 and a second air outlet 202. Both the second air inlet 201 and the second air outlet 202 are connected to the inner cavity of the housing 20. The rotating impeller 10 can be used to drive the air flow inside the housing 20, so that the air inside the housing 20 is blown out from the second air outlet 202, and the air outside the housing 20 flows into the housing 20 through the second air inlet 201, thereby generating airflow. The air blown out from the housing 20 through the second air outlet 202 can be used to drive the air at the heating module 2 to flow out of the housing 1 from the first air outlet 5 on the outer shell 1.

[0056] For example, the housing 20 may include a top plate 21, a side wall 22 and a bottom plate 23. The top plate 21 and the bottom plate 23 are disposed opposite to each other. The side wall 22 is located between the top plate 21 and the bottom plate 23. The two ends of the side wall 22 are fixedly connected to the top plate 21 and the bottom plate 23 respectively. The top plate 21, the bottom plate 23 and the side wall 22 surround and form the inner cavity of the housing 20. The inner cavity of the housing 20 can serve as the inner flow channel of the centrifugal fan 3. At least one of the top plate 21 and the bottom plate 23 is provided with a second air inlet 201, and the side wall 22 is provided with a second air outlet 202.

[0057] For example, the top plate 21 is provided with a second air inlet 201, and the second air outlet 202 is located near the bottom plate 23.

[0058] In this way, the centrifugal fan 3 can take in air from the top plate 21 and take out air from the side wall 22. The air flows more smoothly in the housing 20, which can make the air flow speed in the housing 20, which helps to reduce the noise of the centrifugal fan 3 during operation and increase the air volume of the centrifugal fan 3 during operation.

[0059] In some embodiments, the second air inlet 201 is a circular opening whose axis coincides with the rotation axis of the impeller 10.

[0060] In this embodiment, the centrifugal fan 3 may further include a drive motor 30, which is used to drive the impeller 10 to rotate.

[0061] This application does not limit the type of drive motor 30. For example, the drive motor 30 may include, but is not limited to, an electric motor, a hydraulic motor, etc.

[0062] In some examples, the drive motor 30 may include a stator 32 and a rotor 31, with the stator 32, rotor 31, impeller 10 and rotating shaft 11 arranged coaxially. The stator 32 is fixedly connected to the housing 20, the rotor 31 is fixedly connected to the impeller 10, and the rotor 31 is rotatably connected to the stator 32. The stator 32 is used to drive the rotor 31 to rotate, thereby causing the impeller 10 to rotate relative to the housing 20.

[0063] For example, the centrifugal fan 3 may further include a second circuit board 40, which can be fixedly mounted on the inner wall of the base plate 23. A drive motor 30 can be mounted on the second circuit board 40, and the second circuit board 40 can be electrically connected to the drive motor 30 to supply power to it. The second circuit board 40 can adjust the speed of the drive motor 30 by regulating the voltage and current supplied to it. For example, the stator 32 of the drive motor 30 can be fixedly mounted on and electrically connected to the second circuit board 40.

[0064] For example, the stator 32 of the drive motor 30 can drive the rotor 31 to rotate via electromagnetic induction.

[0065] Figure 4 is a top view of an impeller provided in an embodiment of this application. Figure 5 is a cross-sectional view AA in Figure 2. As shown in Figures 4 and 5, in this embodiment of the application, the impeller 10 includes a hub 200 and multiple blades 100 arranged circumferentially along the hub 200. The blades 100 are fixedly connected to the hub 200, and the hub 200 is connected to the rotating shaft 11.

[0066] In some embodiments, the motor 30 further includes a motor housing 33. In an example where the drive motor 30 includes a stator 32 and a rotor 31, the stator 32, rotor 31, hub 200, motor housing 33, and rotating shaft 11 are coaxially arranged, and the stator 32, rotor 31, motor housing 33, and hub 200 are stacked along the z-direction. The motor housing 33 may be disposed between the hub 200 and the rotor 31, wherein the motor housing 33 is fixedly connected to the rotating shaft 11, and the motor housing 33 includes a first surface 33a and a second surface 33b opposite each other along the z-direction, wherein the hub 200 is fixedly connected to the first surface 33a of the motor housing 33, and the rotor 31 is fixedly connected to the second surface 33b of the motor housing 33.

[0067] This application does not limit the connection method between the blade 100 and the hub 200. For example, the blade 100 can be fixedly connected to the hub 200 by welding, snap-fitting, fastener connection, integral molding, etc.

[0068] For example, as shown in Figures 4 and 6A, one end of the blade 100 near the rotation shaft 11 is connected to the outer wall of the hub 200. In this way, the hub 200 has a smaller impact on the airflow between two adjacent blades 100.

[0069] For example, the blades 100 of the impeller 10 can be evenly distributed along the circumference of the hub 200.

[0070] As shown in Figure 4, the T direction is the rotation direction of the impeller 10. In this embodiment, an airflow channel 300 is formed between two adjacent blades 100 and the top plate 21 and bottom plate 23 shown in Figure 3. An air inlet end 311 of the airflow channel 300 is formed between the ends of two adjacent blades 100 near the rotation shaft 11, and an air outlet end 331 of the airflow channel 300 is formed between the ends of two adjacent blades 100 away from the rotation shaft 11. The air inlet end 311 is connected to the second air inlet 201.

[0071] The rotating outer contour formed by the rotation path of the end of the blade 100 away from the rotating shaft 11 forms an exhaust channel between the side wall 22, the top plate 21, and the bottom plate 23. The air outlet 331 is connected to the second air outlet 202 shown in Figure 2 through the exhaust channel. When the impeller 10 rotates, the air outside the housing 20 enters the airflow channel 300 through the second air inlet 201 shown in Figure 2. The impeller 10 drives the air in the airflow channel 300 to make centrifugal motion, so that the air in the airflow channel 300 enters the exhaust channel through the air outlet 331. The exhaust channel guides the air that enters it to the second air outlet 202, so that the air in the housing 20 is blown out through the second air outlet 202.

[0072] In some examples where the second air inlet 201 is a circular opening whose axis coincides with the rotation axis of the impeller 10, the radius of the second air inlet 201 can be greater than the radius of the rotational inner contour formed by the rotational path of the end of the blade 100 near the rotation axis 11. That is, the radius of the second air inlet 201 can be greater than the distance between the end of the blade 100 near the rotation axis 11 and the rotation axis 11.

[0073] Figure 4 also shows the airflow channel formed between two adjacent blades of the impeller. As shown in Figure 4, in some possible embodiments, the air inlet 311 is located at one end of the airflow channel 300 near the rotating shaft 11, and the air outlet 331 is located at one end of the airflow channel 300 away from the rotating shaft 11.

[0074] From the air inlet 311 to the air outlet 331, the cross-sectional area of ​​the airflow channel 300 gradually increases. As a result, the air velocity gradually increases when the air flows in the airflow channel, which helps to increase the air volume delivered by the centrifugal fan 3 during operation, resulting in lower noise and a larger air volume during operation.

[0075] It should be noted that, unless otherwise specified, in this application, the description of the relative relationships of the various parts of the airflow channel 300, such as the air inlet end 311 and the air outlet end 331, refers to the relative relationships of the various parts of the same airflow channel 300.

[0076] In the embodiments of this application, the airfoil of the blade 100 has a mid-curve 110 including a leading edge end 1111 and a trailing edge end 1121. The leading edge end 1111 is located at the end of the airfoil of the blade 100 near the rotation axis 11, and the trailing edge end 1121 is located at the end of the airfoil of the blade 100 away from the rotation axis 11.

[0077] It should be noted that the airfoil of blade 100 is a cross-section of blade 100, and the cross-section of the airfoil of blade 100 is perpendicular to the extension direction of blade 100 extending from the end near the bottom plate 23 to the end near the top plate 21. For example, when blade 100 extends axially along the rotation axis of impeller 10 from the end near the bottom plate 23 to the end near the top plate 21, the cross-section of airfoil of blade 100 can be perpendicular to the rotation axis of impeller 10.

[0078] The mid-curve 110 of the airfoil of blade 100 is a continuous line segment formed by the centers of the inscribed circles of the airfoil profile of blade 100. In other words, a point on the mid-curve 110 of the airfoil of blade 100 is equidistant from the airfoil profiles on either side of it. Once the mid-curve 110 of the airfoil of blade 100 is determined, the airfoil profile of blade 100 can be determined based on the thickness distribution of blade 100, and thus the shape of blade 100 can be determined.

[0079] In some examples, the blade 100 can be a plate-like structure of uniform thickness.

[0080] In this application, the description of the relative relationships of the structures on the blade 100, such as the middle arc line 110, the leading edge 1111, and the trailing edge 1121, all refer to the relative relationships of the structures on the same blade 100.

[0081] In this application, the blades of the centrifugal fan are swept-back C-shaped, that is, the mid-arc line of the airfoil of the blade is a C-shaped line segment, and the blade is inclined in the opposite direction of the impeller rotation.

[0082] For example, as shown in Figure 4, the mid-arc line 110 of the airfoil of the blade 100 bends in the opposite direction of the rotation direction T of the impeller, that is, the opening direction of the mid-arc line 110 of the airfoil of the blade 100 faces the rotation direction of the impeller.

[0083] Furthermore, along the rotation direction T of the impeller 10, the leading edge 1111 is located in front of the trailing edge 1121, meaning that the line connecting the leading edge 1111 and the trailing edge 1121 is an oblique line, and this oblique line is inclined in the opposite direction of the rotation direction T of the impeller 10. For example, as shown in Figure 4, the line connecting the leading edge 1111 and the trailing edge 1121 is t, and this line t is inclined in the opposite direction of the rotation direction T of the impeller 10, and the angle θ between this line t and the tangent direction of the rotation direction T of the impeller 10 is an obtuse angle.

[0084] Therefore, this centrifugal fan features a swept-back C-shaped design, with the airfoil's mid-arc line being a C-shaped segment that tilts backward. This design allows for applications with low exhaust resistance. The blades have lower wind resistance near the axis of rotation, making it less prone to vortex formation. This allows for smoother airflow into the airflow channel, facilitating airflow that adheres to the blade surface. This reduces noise during impeller rotation and airflow loss, resulting in increased air volume, reduced noise, and improved energy efficiency. It eliminates the need for a soundproof enclosure outside the volute to meet the requirement of low noise under high air volume, and allows for a smaller overall size of the centrifugal fan, making it suitable for use in thinner and lighter electronic devices.

[0085] In some examples, the mid-curve 110 of the airfoil of blade 100 can be a tangentially continuous curve. In this way, blade 100 is easier to process and has a lower manufacturing cost.

[0086] In some examples, the mid-curve 110 of the airfoil of blade 100 can be a curve with continuous curvature. This facilitates airflow within the airflow channel 300 adhering to the surface of blade 100 during rotation, preventing air separation and reducing noise and airflow losses during impeller rotation. Furthermore, the blade 100 is easier and less expensive to manufacture. Additionally, the better adhesion of airflow within the airflow channel 300 to the blade 100 surface, and the reduced noise and airflow losses during impeller rotation, all contribute to lower noise levels and reduced airflow losses.

[0087] In this embodiment of the application, the blades 100 of the impeller 10 have an inlet angle α and an outlet angle β. The inlet angle α of the blade 100 is the angle between the direction of the tangent of the airfoil 110 at the leading edge 1111 pointing outward from the impeller 10 and the opposite direction of the rotation of the leading edge 1111 when the impeller 10 rotates. The outlet angle β of the blade 100 is the angle between the direction of the tangent of the airfoil 110 at the trailing edge 1121 pointing outward from the impeller 10 and the opposite direction of the rotation of the trailing edge 1121 when the impeller 10 rotates.

[0088] In this application, in some possible embodiments, the air inlet angle α of the blade 100 may be less than or equal to 60°. In this case, the air inlet angle α of the blade 100 is the angle between the direction of the tangent at the leading edge 1111 along the central arc 110 pointing outward from the impeller 10 and the opposite direction of the linear velocity of the leading edge 1111 when the impeller 10 rotates.

[0089] In this way, the air inlet angle α of blade 100 is closer to the air inlet angle when the airflow reaches the air inlet of the blade, which is conducive to the airflow entering the airflow channel 300. The airflow in the airflow channel 300 is smoother, which is conducive to the airflow channel 300 having a larger air intake volume and improving the air delivery volume of centrifugal fan 3.

[0090] In addition, vortices are less likely to form at the air inlet 311, which helps to reduce the noise generated by the rotation of the impeller 10 and the loss of airflow.

[0091] In addition, the curvature of the middle arc 110 can be reduced. When air is guided from the part of the blade 100 surface corresponding to the middle arc 110 to the blade 100 surface, the air is less likely to separate from the blade 100 surface, which helps to reduce the noise generated by the rotation of the impeller 10 and the air flow loss.

[0092] For example, the air inlet angle α of blade 100 may include, but is not limited to, 30°, 45°, 55°, 60°, etc.

[0093] In some possible implementations, the outlet angle β of the blade 100 is less than 90°. In this case, the outlet angle β of the blade 100 is the angle between the direction of the tangent along the central arc 110 at the trailing edge 1121 pointing outward from the impeller 10 and the opposite direction of the linear velocity of the trailing edge 1121 when the impeller 10 rotates.

[0094] In this way, the air outlet angle β of the blade 100 is relatively large, which allows the air to flow out of the airflow channel 300 more smoothly, which is conducive to increasing the air volume of the centrifugal fan 3.

[0095] For example, the air outlet angle β of blade 100 may include, but is not limited to, 60°, 75°, 88°, etc.

[0096] In some possible implementations, the leading edge 1111 is located in front of the trailing edge 1121 along the direction of rotation of the impeller 10. This facilitates the blades 100, which have a small inlet angle α, to have a large outlet angle β, allowing air to flow more smoothly out of the airflow channel 300. In some embodiments, the inlet angle α is smaller than the outlet angle β.

[0097] Thus, the curved arc 110, which bends in the opposite direction to the rotation direction of the impeller 10, helps the blades 100 form a smaller inlet angle and a larger outlet angle, resulting in a larger exhaust volume. This makes it suitable for applications with low exhaust resistance. The blades 100 have lower wind resistance at the end near the rotation shaft 11 and are less prone to forming vortices, allowing air to flow smoothly into the airflow channel 300. This facilitates airflow adhering to the surface of the blades 100, reducing noise and airflow loss during impeller 10 rotation. It also helps increase the air volume, reduce noise, and improve energy efficiency during centrifugal fan 3 operation.

[0098] Since the noise generated between the housing 20 and the impeller 10 during the operation of the centrifugal fan 3 is relatively small, it is not necessary to install a soundproof box outside the housing 20 to meet the requirement of low noise under a large air volume. This allows the overall size of the centrifugal fan 3 to be smaller, which is beneficial for its application in thinner electronic devices.

[0099] The embodiments of this application do not limit the curvature of the blade airfoil. In some embodiments, the mid-curvature 110 of the airfoil of the blade 100 can be a second-order Bezier curve.

[0100] For example, Figure 8 is a schematic diagram of the mid-arc line of a blade airfoil provided in an embodiment of this application in the blade rectangular coordinate system. Wherein, the t direction is the positive direction of the horizontal axis of the blade rectangular coordinate system, the m direction is the positive direction of the vertical axis of the blade rectangular coordinate system, P0 is the starting control point, P1 is the intermediate control point, and P2 is the ending control point.

[0101] As shown in Figure 8, in some possible embodiments, the mid-arc line 110 of the airfoil of the blade 100 is a second-order Bézier curve, and the leading edge 1111 and trailing edge 1121 are the starting control point P0 and the ending control point P2 of the second-order Bézier curve, respectively.

[0102] Thus, the design and manufacture of the airfoil of blade 100 are relatively easy. In addition, the formed blade 100 has good aerodynamic performance. When the impeller 10 rotates, it is conducive to the air in the airflow channel 300 adhering to the surface of the formed blade 100 and flowing. The air in the airflow channel 300 is not easy to separate from the surface of blade 100 when flowing, which helps to reduce the noise of the impeller 10 rotating and the airflow loss.

[0103] In some examples where the mid-arc 110 of the airfoil of blade 100 is a second-order Bézier curve, after converting the coordinates in the impeller polar coordinate system to the blade rectangular coordinate system, in the blade rectangular coordinate system, the pole of the impeller polar coordinate system is located on the rotation axis 11, the polar angle of the leading edge 1111 in the impeller polar coordinate system is π / 2, the origin of the blade rectangular coordinate system is located at the leading edge 1111, the horizontal axis direction in the blade rectangular coordinate system is the same as the polar axis direction in the impeller polar coordinate system, and the positive direction of the vertical axis of the blade rectangular coordinate system is the direction from the leading edge 1111 along the radial direction of the impeller 10 to the outside of the impeller 10.

[0104] The value of the second-order Bézier curve can be determined by its calculation formula, which is m(t)=(1-t). 2 P0+2(1-t)tP1+t 2 P2, where t is a parameter, and its value is usually between 0 and 1.

[0105] When t = 0, the point on the curve is located at the initial control point P0.

[0106] When t=1, the point on the curve is located at the termination control point P2.

[0107] When t varies between 0 and 1, the curve exhibits a smooth change, connecting the starting control point P0, the intermediate control point P1, and finally reaching the ending control point P2.

[0108] In this application, t satisfies: 0 < t < 1.

[0109] This allows point P0 to have coordinates of (0,0), point P2 to have an x-coordinate greater than 0, and point P2 to have a y-coordinate of, for example, 1. Point P1 can have an x-coordinate greater than point P2, and point P1 can have a y-coordinate greater than 0 and less than point P2.

[0110] Thus, the blade 100 has lower wind resistance at the end near the rotating shaft 11 and is less prone to forming vortices, allowing air to flow smoothly into the airflow channel 300. This facilitates airflow adhering to the surface of the blade 100, reducing noise and airflow losses during impeller 10 rotation, and improving the airflow volume, noise, and energy efficiency of the centrifugal fan 3. Furthermore, the airfoil of the blade 100 closely matches the airflow field within the airflow channel 300, and the airfoil's strong resistance to adverse pressure gradients makes it difficult for the air flowing against the blade 100 to separate from it during impeller 10 rotation. This ensures smoother airflow within the airflow channel 300, further reducing noise and airflow losses during impeller 10 rotation, and improving the airflow volume, noise, and energy efficiency of the centrifugal fan 3. Furthermore, due to the high degree of fit between the airfoil of the blade 100 and the airflow field within the airflow channel 300, the blade 100 exhibits good aerodynamic performance. This results in high work efficiency of the blade 100 during rotation, leading to higher energy efficiency for the centrifugal fan 3 during operation. Additionally, the air pressure exiting from the outlet 331 is relatively high, resulting in a higher airflow rate for the centrifugal fan 3. Moreover, the size of the blade 100 can be adjusted according to the formula of the second-order Bezier curve, facilitating the manufacture of centrifugal fans 3 of different sizes with larger airflow rates and lower noise levels.

[0111] In the process of converting coordinates in the impeller polar coordinate system to coordinates in the blade rectangular coordinate system, the coordinates in the impeller polar coordinate system can be converted to the impeller rectangular coordinate system first by the polar coordinate system to rectangular coordinate system conversion method, and then the coordinates in the impeller rectangular coordinate system can be converted to the blade rectangular coordinate system by translation and other methods.

[0112] In this system, the origin of the impeller rectangular coordinate system is located on the rotation axis 11. The horizontal axis of the impeller rectangular coordinate system coincides with the polar axis of the impeller polar coordinate system. The positive direction of the vertical axis of the impeller rectangular coordinate system is the direction from the rotation axis 11 along the radial direction of the impeller 10 to the outside of the impeller 10. The units of the horizontal and vertical coordinates in the blade rectangular coordinate system are the same. For example, the units of the horizontal and vertical coordinates in the blade rectangular coordinate system can be meters, decimeters, centimeters, etc.

[0113] The centrifugal fan provided in this application embodiment has a blade 100 with a mid-arc 110 that adopts a second-order Bézier curve. This reduces noise and airflow loss during impeller rotation, which is beneficial for increasing air volume, reducing noise, and improving energy efficiency during centrifugal fan operation. Furthermore, the blade size can be adjusted according to this second-order Bézier curve, making it easy to manufacture centrifugal fans of different sizes with larger air volume and lower noise.

[0114] In this application, when airflow flows into the housing 20 through the second air inlet 201, part of it directly enters the airflow channel of the blade 100 (airflow a in Figure 5), while part flows towards the upper surface of the hub 200 (airflow b in Figure 5), and the hub 200 guides the airflow to the air inlet end of the blade 100. However, when the hub 200 is parallel to the top plate 21, most of the airflow is guided to the first leading edge of the blade 100, resulting in uneven airflow from the centrifugal fan and affecting the heat dissipation effect. As shown in Figures 5 and 7, the blade 100 can be divided into a first leading edge 101 and a second leading edge 102 connected by the connection point between the blade 100 and the hub 200. The first leading edge 101 of the blade 100 is closer to the second air inlet 201, and the second leading edge 102 of the blade 100 is located on the side of the first leading edge 101 away from the second air inlet 201.

[0115] Therefore, this application improves the structure of the hub 200. Figure 6A is a schematic diagram of the structure of an impeller provided in an embodiment of this application. Figure 6B is a sectional view of BB in Figure 6A. As shown in Figures 6A and 6B, the hub 200 includes: a first region 2001 and a second region 2002. Referring to Figure 5, the first region 2001 is connected to the rotating shaft 11 through the motor housing 33. The second region 2002 is arranged around the first region 2001. The second region 2002 includes a first side and a second side opposite to each other. The first side of the second region 2002 is connected to the first region 2001, and the second side of the second region 2002 is connected to the blade 100. The first side of the second region 2002 is higher than the second side of the second region 2002.

[0116] In this application, the hub 200 is divided into two regions, and the second region 2002 of the hub 200 gradually moves away from the second air inlet 201. When the airflow flows into the housing through the second air inlet 201, part of it directly enters the airflow channel of the blade 100 (airflow a in Figure 5), and part of it flows toward the hub 200 (airflow b in Figure 5) and is guided by the hub 200 to the airflow channel of the blade 100. Since the hub 200 is located in the middle of the air inlet end of the airflow channel of the blade 100, it will block the second leading edge 102 of the blade 100. In this application, the second region 2002 of the hub 200 gradually tilts toward the blade 100, which can better guide the airflow into the airflow channel of the second leading edge of the blade 100, making the air intake at each position of the blade 100 more uniform.

[0117] In some embodiments, in a direction away from the second air inlet 201, the second region 2002 is inclined from the first side toward the second side along the radial direction of the impeller. That is, the second region 2002 is a slope. In this way, airflow can be directed through the second region 200 to the second leading edge 102 of the blade, making the air intake more uniform at all positions of the blade 100 and improving the performance of the fan.

[0118] For example, the hub 200 is generally shaped like a frustum, with the first region 2001 of the hub 200 serving as the top surface of the frustum and the second region 2002 serving as the side surface of the frustum. The longitudinal section of the hub 200 can be approximated as an isosceles trapezoid. Thus, the second region 2002 of the hub 200 has a consistent circumferential tilt angle, which can more evenly guide airflow to the second leading edge 102 of the blades, resulting in more uniform air intake at all positions of the blades 100 and improving fan performance.

[0119] In this embodiment, the tilt angle of the second region 2002 is not limited, as long as the second region 2002 can guide the airflow to the air inlet end of the second leading edge of the blade. For example, the extension line of the second region 2002 can intersect with the second leading edge 102 of the blade. In this way, the airflow can be better guided into the airflow channel of the second leading edge of the blade 100.

[0120] In some embodiments, the hub 200 may be designed with an inclined surface, meaning that in the direction away from the second air inlet 201, the surface of the hub 200 facing the air inlet 201 is inclined radially toward the blade 100 along the impeller from the rotation axis 11. This allows airflow to be guided through the upper surface of the hub 200 to the second leading edge 102 of the blade, resulting in more uniform air intake at all positions of the blade 100 and improved fan performance. Here, radial direction refers to a straight line along the diameter or radius, or a straight line perpendicular to the rotation axis 11.

[0121] For example, the hub 200 is conical, and its longitudinal section can be an isosceles triangle. The conical hub 200 can be coaxially arranged with the rotating shaft 11, and its outer edge is connected to the blade 100. In this way, the hub 200 has a consistent circumferential tilt angle, which can more evenly guide airflow to the second leading edge 102 of the blade, resulting in more uniform air intake at all positions of the blade 100 and further improving the fan's performance.

[0122] In this embodiment, the tilt angle of the hub 200 as a whole is not limited, as long as the hub 200 can guide the airflow to the air inlet end of the second leading edge of the blade. For example, the extension line of the hub 200 can intersect with the second leading edge 102 of the blade. In this way, the airflow can be better guided into the airflow channel of the second leading edge 102 of the blade 100.

[0123] In this embodiment, the hub 200 is conical, and it gradually moves away from the second air inlet 201 towards the blade 100. When airflow flows into the housing through the second air inlet 201, part of it directly enters the airflow channel of the blade 100 (airflow a in Figure 5), while part flows towards the hub 200 (airflow b in Figure 5) and is guided by the hub 200 to the airflow channel of the blade 100. In this application, the hub 200 gradually tilts towards the blade 100, which can better guide the airflow into the airflow channel of the second leading edge of the blade 100, making the air intake more uniform at all positions of the blade 100. The entire hub 200 adopts a conical design, which can better guide the airflow to the blade.

[0124] To better guide airflow into the airflow channel, the shape of the air inlet end of the airflow channel can be adjusted in some embodiments. Figure 7 is a schematic diagram of a blade structure provided in an embodiment of this application. For example, as shown in Figures 6B and 7, the blade 100 includes: a leading edge near the rotation shaft 11, the leading edge of the blade including: a first leading edge 101 and a second leading edge 102 connected in sequence, the first leading edge 101 including: a first end 101A and a second end 101B opposite to each other, the second leading edge 102 including: a third end 102A and a fourth end 102B opposite to each other, the first end 101A of the first leading edge 101 is close to the second air inlet 201, the second end 101B of the first leading edge 101 and the third end 102A of the second leading edge 102 are both connected to the hub 200, and the fourth end 102B of the second leading edge 102 is away from the second air inlet 201.

[0125] As shown in Figure 6B, the distance between the first end of the first leading edge 101 and the rotation axis 11 is greater than the distance between the second end of the first leading edge 101 and the rotation axis 11.

[0126] The leading edge of the blade is divided into two parts, and the first leading edge 101 of the blade 100 is gradually brought closer to the hub 200. See the enlarged view c in Figure 6B. When the airflow a flows to the first leading edge 101 of the blade, the angle d between the direction of the airflow a and the first leading edge 101 of the blade is close to 90°, so that the airflow a can enter the airflow channel of the blade better.

[0127] For example, in a direction away from the second air inlet 201, the first leading edge 101 is inclined radially toward the rotating shaft 11 along the impeller.

[0128] In this embodiment, the tilt angle of the first leading edge is not limited; it is only necessary to make the angle between the airflow entering through the air inlet and the leading edge of the blade more conducive to air entry. For example, the tilt angle of the first leading edge 101 can be adjusted so that the angle between the airflow a entering through the air inlet and the first leading edge 101 is close to 90°, so that the airflow a can better enter the airflow channel of the blade 100.

[0129] In addition, the first leading edge 101 adopts an inclined design, that is, the air inlet end surrounded by the first leading edge adopts an inclined design, which makes the air inlet end open, increases the opening size of the air inlet end, and is conducive to increasing the air intake volume of the air inlet end.

[0130] The extension direction of the second leading edge 102 is not limited in this embodiment. In some embodiments, the second leading edge 102 is parallel to the rotation axis 11. However, there may be errors in the parallelism between the second leading edge 102 and the rotation axis 11; for example, the angle between the second leading edge 102 and the rotation axis 11 may be 0-5°.

[0131] Therefore, the second leading edge can be used to receive the airflow after the hub is guided. By adjusting the guide angle of the hub, the airflow can be guided into the airflow channel of the second leading edge of the blade.

[0132] In other embodiments, the distance between the first end of the second leading edge 102 and the rotation axis is greater than the distance between the second end of the second leading edge 102 and the rotation axis.

[0133] Therefore, the leading edge of the blade is divided into two parts, and the second leading edge of the blade gradually approaches the hub. When the hub guides the airflow to the second leading edge of the blade, the angle between the airflow direction and the second leading edge of the blade can be close to 90°, allowing the airflow to enter the airflow channel of the blade better.

[0134] For example, as shown in Figure 6B, the second leading edge 102 is inclined toward the rotation axis 11 in the radial direction of the impeller in a direction away from the second air inlet 201.

[0135] The embodiments of this application do not limit the tilt angle of the second leading edge, as long as the angle between the airflow entering the air inlet and the leading edge of the blade is more conducive to airflow entry. For example, the tilt angle of the second leading edge can be adjusted so that the angle between the airflow guided by the inclined surface of the hub (i.e., the inclined surface of the hub) and the first leading edge is close to 90°, so that the airflow can better enter the airflow channel of the blade.

[0136] Referring again to FIG7, in some embodiments of this application, as shown in FIG7, the blade 100 further includes a transition portion 103, which protrudes from the blade 100 and is used to connect with the hub 200.

[0137] The transition section 103 includes a first surface 1031 and a second surface 1032 connected to each other. The first surface 1031 is connected to the first leading edge 101 of the blade 100. The first surface 1031 can be an arc-shaped surface. In this way, the transition between the first surface 1031 and the surface of the hub 200 is smoother, which can better guide the airflow to the airflow channel of the blade 100.

[0138] The second surface 1032 of the transition portion 103 is used to connect with the hub 200. In some embodiments, the second surface 1032 can be a slope and is adapted to the shape of the hub 200, resulting in a larger contact surface with the hub 200 and a more stable connection.

[0139] Referring again to Figure 7, the blade 100 may further include a groove 104, which is connected to the second surface 1032 of the transition portion 103. The groove 104 is adapted to the shape of the edge of the hub 200, for example. When the blade 100 is connected to the hub 200, the hub 200 portion is connected to the second surface 1032 of the transition portion 103, and the edge portion of the hub 200 extends into the groove 104 and engages with the groove 104, further improving the stability of the connection between the blade 100 and the hub 200.

[0140] To improve the shock resistance of the centrifugal fan, in some embodiments, as shown in Figures 3 and 9, a crossbeam 211 can be provided on the top plate 21 to limit the rotation shaft 11 and prevent it from swaying up and down in the housing. For example, the crossbeam 211 is located in the second air inlet 201 and is connected to the top cover. The crossbeam 211 includes a connecting portion 213 and a protrusion 212 protruding towards the bottom plate 23, which is rotatably connected to the rotation shaft 11. In some embodiments, the gap between the crossbeam 211 and the upper end of the rotation shaft 11 can be 0.1-0.3 mm.

[0141] Thus, by setting a crossbeam 211 on the top plate 21 and a protrusion 212 on the crossbeam 211, the rotating shaft 11 can be limited, preventing the rotating shaft 11 from swaying up and down in the housing and enhancing the centrifugal fan's ability to resist drop impacts.

[0142] The embodiments of this application do not limit the structure of the protrusion 212. In some embodiments, as shown in FIG9, the thickness of the protrusion 212 is greater than the thickness of the connecting portion 213. That is, the axial (z direction in FIG5) limiting of the rotating shaft 11 shown in FIG5 can be achieved by increasing the local thickness of the crossbeam 211 to form the protrusion 212 on the crossbeam 211.

[0143] The embodiments of this application do not limit the forming method of the protrusion 212. In some examples of this embodiment, the protrusion 212 and the connecting part 213 can be integrally formed.

[0144] In other examples of this embodiment, the protrusion 212 and the connecting portion 213 can be formed independently before being connected.

[0145] In some embodiments, as shown in FIG10, the protrusion 212 and the connecting portion 213 have the same thickness, and the protrusion 212 can be formed by bending the crossbeam 211. Thus, by bending the crossbeam 211, the protrusion 212 can be formed on the crossbeam 211. Compared with providing a thicker protrusion 212 on the crossbeam 211, the weight of the crossbeam 211 can be reduced, materials can be saved, and it is beneficial to miniaturize and lighten the device.

[0146] To further improve the shock resistance of the centrifugal fan, in some embodiments, as shown in FIG9, a limiting member can be provided on the side of the protrusion 212 near the base plate, so that the rotating shaft 11 extends into the limiting member, and the rotating shaft 11 and the limiting member can be rotatably connected.

[0147] Thus, by setting a limiting member on the protrusion 212, the left and right movement of the rotating shaft 11 can be prevented, which not only enhances the impact resistance but also helps to avoid the generation of shaking noise.

[0148] This application does not limit the structure of the limiting member 214. When the thickness of the protrusion 212 is greater than the thickness of the connecting portion 213, referring to FIG9, the limiting member 214 can be a limiting groove provided on the protrusion 212. For example, a limiting groove can be provided on the surface of the protrusion 212 facing the base plate, allowing the rotating shaft 11 to extend into the limiting groove, and the rotating shaft 11 and the limiting groove to be rotatably connected.

[0149] Thus, by setting a limiting groove on the protrusion 212, the left and right movement of the rotating shaft 11 can be prevented, which not only enhances the impact resistance but also helps to avoid the generation of shaking noise.

[0150] When the thickness of the protrusion 212 is equal to the thickness of the connecting portion 213, that is, when the protrusion 212 can be formed by bending the crossbeam 211, referring to FIG10, the limiting member 214 can be an annular member 215 provided on the protrusion 212. For example, an annular member 215 can be provided on the surface of the protrusion 212 facing the base plate, such that the rotating shaft 11 extends into the annular member 215, and the rotating shaft 11 and the annular member 215 can be rotatably connected.

[0151] Thus, by providing an annular part 215 on the protrusion 212, the left and right movement of the rotating shaft 11 can be prevented, which not only enhances the impact resistance but also helps to avoid the generation of shaking noise.

[0152] To further improve the impact resistance of the centrifugal fan, in some embodiments, as shown in Figure 5, the centrifugal fan further includes a central tube 231 sleeved on the outside of the rotating shaft 11. The rotating shaft 11 and the central tube 231 are coaxially arranged, and the central tube 231 can be integrally formed with the base plate 23. Therefore, by integrally forming the central tube 231 with the base plate 23, the impact resistance of the centrifugal fan is enhanced, and its drop protection performance can be further improved.

[0153] Figure 11 is a schematic diagram of the structure of the middle tube provided in an embodiment of this application. Figure 12 is a schematic diagram of the structure of the middle tube and the shell provided in an embodiment of this application. In some embodiments, as shown in Figures 11 and 12, the middle tube 231 includes a first part 231a and a second part 231b. The first part 231a is disposed near the bottom plate 23, and the wall thickness of the first part 231a is greater than the wall thickness of the second part 231b. In this way, the wall thickness of the middle tube 231 near the bottom plate 23 is increased, achieving local reinforcement and further improving the centrifugal fan's resistance to drop impacts.

[0154] To improve the dustproof and waterproof performance of the centrifugal fan, in some embodiments, as shown in Figures 5, 11, and 12, the centrifugal fan further includes a first sealing ring 232, which is disposed between the motor and the intermediate tube 231. Therefore, by providing the first sealing ring 232, airflow can be prevented from entering the intermediate tube 231 through the gap between the motor and the intermediate tube 231, thus facilitating dustproof and waterproof performance and improving the sealing performance of the centrifugal fan.

[0155] This application does not limit the structure of the first sealing ring 232. In some embodiments, the projection of the first sealing ring 232 on the side wall is an inverted T-shape. That is, the first sealing ring 232 includes a first sealing part 232a and a second sealing part 232b. The first sealing part 232a is disposed, for example, in the gap between the rotor 31 and the stator 32 of the motor, and the second sealing part 232b is disposed, for example, in the gap between the rotor 31 and the middle tube 231 of the motor. The first sealing part 232a can extend towards the impeller direction, that is, the thickness of the first sealing part 232a is greater than the thickness of the second sealing part 232b, so that the first sealing ring 232 as a whole has an inverted "T" shape design.

[0156] This design allows the airflow channels inside the centrifugal fan to form a labyrinthine structure, further improving the sealing performance of the centrifugal fan.

[0157] In some embodiments of this application, as shown in Figures 5 and 12, the centrifugal fan further includes a bearing 111, which is sleeved on the rotating shaft 11 and disposed inside the central tube 231, with a gap between the bearing 111 and the rotating shaft 11. By providing the bearing 111, the friction between the rotating shaft 11 and the central tube 231 can be reduced, resulting in smoother rotation of the rotating shaft 11 and extending the service life of the equipment.

[0158] In some embodiments, to further reduce friction between devices, a lubricating oil and a second sealing ring 112 are also provided inside the central tube 231. The second sealing ring 112 is sleeved on the rotating shaft 11, and is located on the side of the bearing 111 near the top plate 21. Thus, by providing the second sealing ring 112, the lubricating oil in the bearing 111 can be prevented from leaking out, and airflow can be further prevented from entering the central tube 231, achieving dust and water protection and improving the sealing performance of the centrifugal fan.

[0159] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any changes or substitutions within the technical scope disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A centrifugal fan, characterized in that, The application relates to a fan, which comprises a shell, a rotating shaft and an impeller, the shell is provided with an air inlet and an air outlet, the impeller and the rotating shaft are arranged in a cavity surrounded by the shell, the air inlet and the air outlet are communicated with the cavity, the rotating shaft is rotationally connected with the shell, the impeller is connected with the rotating shaft, the impeller comprises a hub and blades fixedly connected with the hub, the middle camber line of the airfoil of the blade is curved in the opposite direction of the rotating direction of the impeller, the middle camber line of the airfoil of the blade comprises a leading edge end and a trailing edge end, the leading edge end is located at one end of the blade close to the rotating shaft, the trailing edge end is located at one end of the blade away from the rotating shaft, and the leading edge end is located in front of the trailing edge end in the rotating direction of the impeller. The air inlet angle of the blade is less than 60 degrees.

2. The centrifugal fan according to claim 1, characterized in that The air outlet angle of the blade is less than 90 degrees.

3. The centrifugal fan according to claim 1 or 2, characterized in that The surface of the hub towards the air inlet comprises a first region and a second region connected with each other, the first region is rotationally connected with the shell, the second region is arranged around the first region, the second region comprises opposite first and second side edges, the first side edge of the second region is connected with the first region, the second side edge of the second region is connected with the blade, and the distance between the first side edge of the second region and the air inlet is less than the distance between the second side edge of the second region and the air inlet.

4. The centrifugal fan according to any one of claims 1 to 3, characterized in that In the direction away from the air inlet, the second region is inclined from the first side edge to the second side edge in the radial direction of the impeller.

5. The centrifugal fan according to claim 4, wherein In the direction away from the air inlet, the surface of the hub towards the air inlet is inclined from the rotating shaft to the blade in the radial direction of the impeller.

6. The centrifugal fan according to any one of claims 1 to 3, characterized in that The leading edge of the blade comprises a first leading edge and a second leading edge connected in sequence, the second end of the first leading edge and the first end of the second leading edge are both connected with the hub, the first end of the first leading edge is close to the air inlet, and the distance between the first end of the first leading edge and the rotating shaft is greater than the distance between the second end of the first leading edge and the rotating shaft.

7. The centrifugal fan according to any one of claims 1 to 6, characterized in that In the direction away from the air inlet, the first leading edge is inclined towards the rotating shaft.

8. The centrifugal fan according to claim 7, characterized in that The second leading edge is parallel to the rotating shaft.

9. The centrifugal fan according to claim 7 or 8, characterized in that The distance between the first end of the second leading edge and the rotating shaft is greater than the distance between the second end of the second leading edge and the rotating shaft.

10. The centrifugal fan according to claim 7 or 8, characterized in that In the direction away from the air inlet, the second leading edge is inclined towards the rotating shaft.

11. The centrifugal fan according to claim 10, wherein The impeller comprises a plurality of blades arranged in the circumferential direction of the hub, an airflow channel is formed between two adjacent blades, an air inlet of the airflow channel is formed between the end portions of the two adjacent blades close to the rotating shaft, an air outlet of the airflow channel is formed between the end portions of the two adjacent blades away from the hub, and the cross section of the airflow channel gradually increases from the air inlet to the air outlet of the airflow channel.

12. The centrifugal fan according to any one of claims 1-11, characterized in that The middle camber line of the airfoil of the blade is a second-order Bezier curve, and the leading edge end and the trailing edge end are respectively a starting control point and a terminal control point of the second-order Bezier curve.

13. The centrifugal fan according to any one of claims 1-12, characterized in that ​ After the coordinate in the impeller polar coordinate system is converted into the coordinate in the blade rectangular coordinate system, the pole point in the impeller polar coordinate system is located on the rotation axis of the hub, the polar angle of the leading edge end in the impeller polar coordinate system is π / 2, the origin of the blade rectangular coordinate system is located at the leading edge end, the horizontal axis direction in the blade rectangular coordinate system is the same as the polar axis direction in the impeller polar coordinate system, and the positive direction of the vertical axis of the blade rectangular coordinate system is the direction in which the leading edge end points to the outside of the impeller in the radial direction of the impeller.

14. The centrifugal fan according to any one of claims 1-13, characterized in that The shell comprises a side wall, and oppositely arranged bottom plate and top plate, the rotation axis and the side wall are arranged between the top plate and the bottom plate, the side wall, the top plate and the bottom plate jointly enclose the cavity, the top plate is provided with an air inlet, and the side wall is provided with an air outlet.

15. The centrifugal fan of claim 14, wherein The centrifugal fan comprises a cross beam arranged in the air inlet and connected with the top plate, the cross beam comprises a connecting portion and a convex portion, the connecting portion is used for connecting the convex portion and the top plate, and the convex portion protrudes towards the bottom plate and is rotationally connected with the rotation axis.

16. The centrifugal fan of claim 15, wherein The convex portion and the connecting portion have the same thickness, and the convex portion is formed by bending the cross beam.

17. The centrifugal fan of claim 16, wherein The convex portion is provided with a ring-shaped member on the side thereof facing the bottom plate, and the rotation axis is rotationally connected with the ring-shaped member.

18. The centrifugal fan of claim 15, wherein, The thickness of the convex portion is greater than that of the connecting portion.

19. The centrifugal fan of claim 18, wherein The convex portion is provided with a limiting member on the side thereof close to the bottom plate, and the rotation axis is rotationally connected with the limiting member.

20. The centrifugal fan according to any one of claims 14-19, characterized in that The centrifugal fan further comprises a middle pipe sleeved outside the rotation axis, the rotation axis and the middle pipe are coaxially arranged, and the middle pipe and the bottom plate are integrally formed.

21. The centrifugal fan of claim 20, wherein The middle pipe comprises a first portion and a second portion connected with each other, the first portion is connected with the bottom plate, the second portion is arranged on the side of the first portion away from the bottom plate, and the side wall thickness of the first portion is greater than that of the second portion.

22. The centrifugal fan according to claim 20 or 21, characterized in that The centrifugal fan further comprises a motor shell, a motor and a first sealing ring, the motor shell is connected with the rotation axis, the motor shell is arranged between the hub and the motor, and the first sealing ring is sleeved on the middle pipe and partially arranged between the motor and the middle pipe.

23. The centrifugal fan of claim 22, wherein, The projection of the first sealing ring on the side wall is in the shape of an inverted T.

24. The centrifugal fan according to any one of claims 20-23, characterized in that The centrifugal fan further comprises a bearing and a second sealing ring, the bearing and the second sealing ring are arranged in the middle pipe and sleeved on the rotation axis, the bearing is rotationally connected with the rotation axis, and the second sealing ring is arranged on the side of the bearing close to the top plate.

25. An electronic device, comprising: The centrifugal fan is used for dissipating heat of a heat generating module.

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