Centrifugal fan and air cooling system

Abstract

A centrifugal fan and an air cooling system. A centrifugal fan (10) comprises an impeller (12) arranged in a cavity (111) of a housing (11); an airflow channel (115) is formed between the impeller (12) and an inner side surface (112) of the cavity (111); the inner side surface (112) of the cavity (111) comprises a raised surface (1121), a first flow guide surface (1122), and a second flow guide surface (1123) which are sequentially connected; a first distance from the intersection of the raised surface (1121) and the first flow guide surface (1122) to a circumferential side surface (121) of the impeller (12) is greater than a second distance from the intersection of the first flow guide surface (1122) and the second flow guide surface (1123) to the circumferential side surface (121). The narrowest position of the airflow channel is relatively far away from the raised surface, so that the second distance is smaller, and the first distance is larger, keeping the noise level low while improving the air outflow performance of the centrifugal fan, achieving both performance improvement and noise reduction.

Description

Centrifugal fan and air cooling system

[0001] This application claims priority to the Chinese patent application filed with the China Patent Office on September 7, 2023, with application number 202311155752.0 and application name “Centrifugal Fan and Air Cooling System”, the entire contents of which are incorporated by reference into this application. Technical Field

[0002] The present application relates to the technical field of heat dissipation of electronic equipment, and in particular to a centrifugal fan and an air cooling system. Background Art

[0003] As the performance demands on electronic devices continue to increase, power consumption and heat generation are also deteriorating. The heat generated by electronic devices needs to be dissipated into the environment in a timely manner. Air cooling technology is currently one of the main heat dissipation methods for electronic devices. The fans in the air cooling system greatly determine the performance of the device's air cooling. Moreover, as electronic devices are closely integrated into people's lives, fan noise can also greatly affect the user experience of electronic devices. Considering the demand for thinner and lighter electronic devices and the characteristics of fan types, electronic equipment air cooling systems typically use centrifugal fans to achieve heat dissipation. However, in miniaturized electronic devices, it is difficult to balance the need for improved centrifugal fan air output performance with the problem of controlling wind noise.

[0004] Summary of the Invention

[0005] The embodiment of the present application provides a centrifugal fan and an air cooling system. The centrifugal fan can meet the needs of improving the fan's air outlet performance while not worsening the noise, thereby achieving the effect of improving the fan's heat dissipation performance while reducing the fan noise.

[0006] A first aspect of an embodiment of the present application provides a centrifugal fan comprising a housing and an impeller, wherein the housing has a cavity, the housing has an air inlet and an air outlet, the impeller is rotatably disposed within the cavity, and a gap is formed between the circumferential side surface of the impeller and the inner side surface of the cavity to form an air flow channel, the air outlet and the air inlet are respectively connected to the air flow channel. The rotation of the impeller can accelerate the flow of air within the air flow channel, allowing air outside the cavity to quickly enter through the air inlet and be discharged from the air outlet at high speed after passing through the air flow channel, thereby achieving a heat dissipation function.

[0007] The inner side surface of the cavity includes a raised surface, a first guide surface, and a second guide surface, which are connected in sequence. The raised surface is connected to one end of the air outlet, and the second guide surface is connected to the other end of the air outlet. From the end where the second guide surface is connected to the first guide surface to the end where the second guide surface is connected to the air outlet, the distance between the second guide surface and the circumferential side surface of the impeller in the radial direction gradually increases. In other words, starting from the end where the second guide surface is connected to the first guide surface, the airflow channel has a region where the width (width in the radial direction) gradually widens from narrow. This region can serve as the pressurization zone of the centrifugal fan. When the airflow passes through this region where the airflow gradually widens from narrow, it can be pressurized to increase the air output of the fan.

[0008] The radial distance between the intersection line of the raised surface and the first guide surface and the peripheral side surface of the impeller is the first distance. The first distance can be the length of the line segment between the intersection point of the radial line and the peripheral side surface of the impeller and the intersection point of the radial line and the intersection line.

[0009] The distance in the radial direction between the intersection line of the first guide surface and the second guide surface and the peripheral side surface of the impeller is the second distance. The second distance can be the length of the line segment between the intersection point of the radial line and the peripheral side surface of the impeller and the intersection point of the radial line and the intersection line.

[0010] The second distance is smaller than the first distance. The raised surface can be formed by a raised surface on the inner side surface of the cavity. The raised surface is raised toward the cavity, which will cause the airflow channel to undergo a sudden change in size at the position of the raised surface. It can also be understood that, in the direction from the raised surface to the second guide surface, the airflow channel undergoes a change in width from wide to narrow at the position of the raised surface, and the airflow channel undergoes a second change from wide to narrow at the position of the first guide surface. The narrowest position of the airflow channel is located at the position where the second guide surface and the first guide surface meet. The narrowest position of the airflow channel is relatively far away from the raised surface (the sudden change in size). Compared with the centrifugal fan of the related art, under the same noise requirements (such as the same spacing between the raised surface and the peripheral side surface), the second distance can be relatively smaller, which can make the centrifugal fan have a stronger pressurization capacity, make the centrifugal fan's air outlet performance stronger, and help improve the heat dissipation performance of the centrifugal fan, while improving the heat dissipation performance to ensure that the noise does not deteriorate.

[0011] Moreover, since the second distance is smaller than the first distance, the change in width between the raised surface and the peripheral surface of the impeller has a relatively small effect on the performance of the centrifugal fan. Therefore, the first distance can be relatively larger, reducing the rate of change of the cross-sectional area from the air outlet position to the raised surface. When the impeller rotates and passes through the raised surface position, the size mutation at this position can be reduced to a certain extent, so that the pressure pulsation generated at the raised surface position is weakened, thereby reducing noise and achieving noise reduction of the centrifugal fan. It can achieve a balance between fan performance improvement and noise reduction to a certain extent, and achieve both performance improvement and noise reduction of the centrifugal fan at the same time.

[0012] In one possible implementation, the radial distance between the first guide surface and the circumferential side surface of the impeller gradually decreases from the end where the first guide surface connects to the raised surface to the end where the first guide surface connects to the second guide surface, thereby forming a channel with a gradually decreasing width in the direction from the raised surface to the second guide surface. In other words, a gradually decreasing channel is provided between the raised surface and the pressurized area formed by the second guide surface and the circumferential side surface, facilitating the reduction of the second distance compared to the first distance, while also providing a smoother transition and reducing noise caused by width changes, thereby further reducing noise while improving centrifugal fan performance.

[0013] In one possible implementation, the distance in the radial direction between the first guide surface and the circumferential side surface of the impeller decreases monotonically from the end where the first guide surface is connected to the raised surface to the end where the first guide surface is connected to the second guide surface. Under the condition that the distance between the first guide surface and the circumferential side surface of the impeller decreases, it is beneficial to reduce the structural design difficulty of the first guide surface and facilitate design and production implementation.

[0014] In one possible implementation, the first guide surface is an arcuate surface that curves toward the impeller, and the convex surface includes a first arcuate surface, which is an arcuate surface that bulges toward the cavity. One end of the first arcuate surface is connected to the first guide surface to form a curved surface, and the intersection line of the convex surface and the first guide surface is a straight line that passes through the concave and convex inflection points of the curved surface and is perpendicular to the radial direction. Making both the first guide surface and the convex surface arcuate provides good smoothness, facilitating a smooth transition of airflow within the gradually narrowing channel formed between the first guide surface and the peripheral side surface. It also improves the smoothness of the connection between the second arcuate surface and the arcuate first guide surface, reducing the impact of width variations on airflow and improving the airflow and noise reduction performance of the centrifugal fan.

[0015] In one possible implementation, the second air guide comprises a second curved surface and a second flat surface connected to the first air guide surface, wherein the second curved surface is connected to the first air guide surface, and the second flat surface is connected to the air outlet. By making the portion of the second air guide surface connected to the first air guide surface a second curved surface, air flow in the pressurized area can be made smoother, reducing gas energy dissipation, and more conducive to pressurizing the air, thereby improving the air outlet performance of the centrifugal fan.

[0016] In addition, by making the portion where the second guide surface is connected to the air outlet a second plane, it is beneficial to expand the opening of the air outlet and also beneficial to improve the air outlet performance of the centrifugal fan.

[0017] In one possible implementation, the second curved surface and the first guide surface are connected to form a curved surface that bends toward the impeller, which has excellent smoothness, so that the airflow can smoothly transition between the gradually narrowing channel formed by the first guide surface and the peripheral side surface to the pressurized area channel formed by the second guide surface and the peripheral side surface, further reducing the impact of changes in width on the airflow, and ensuring the pressurization effect of the airflow, which is beneficial to improving the air outlet and noise reduction performance of the centrifugal fan.

[0018] In one possible implementation, the raised surface also includes a first plane connected to the other end of the first curved surface, and the first plane is connected to the air outlet. From the end where the first plane is connected to the first curved surface to the end where the first plane is connected to the air outlet, the first plane is inclined toward the outside of the cavity, so that the outlet position is open, which can further increase the opening of the air outlet and help improve the air outlet performance of the centrifugal fan.

[0019] In one possible implementation, the housing includes side walls, an opposing bottom wall, and a top wall. The side walls are positioned between the bottom and side walls, and the side walls, bottom, and top walls collectively form a cavity. An air inlet is defined on at least one of the bottom and top walls, and an air outlet is defined on the side walls. The inner surface of the side walls forms the inner side surface of the cavity. Assembling the bottom, side, and top walls to form the housing enhances flexibility in housing assembly and facilitates production.

[0020] In one possible implementation, the impeller includes a wheel disc and multiple blades, one end of the multiple blades is fixed on the wheel disc, and the other end faces of the multiple blades are flush with the peripheral side of the impeller. The multiple blades are conducive to increasing the air output of the centrifugal fan, thereby improving the heat dissipation performance of the centrifugal fan.

[0021] The second aspect of the embodiment of the present application provides an air cooling system for dissipating heat from a heating device, including a heat dissipation device, a heat transfer device, and any of the above-mentioned centrifugal fans. The heat dissipation device is located at the outlet of the centrifugal fan, and the heat dissipation device is connected to the heat transfer device, and the heat transfer device is used to connect to the heating device. By including a centrifugal fan, the centrifugal fan can achieve the purpose of noise reduction while meeting the condition of improving the air outlet performance, while taking into account that the noise does not worsen, and at the same time, it can achieve the effect of improving the heat dissipation performance of the centrifugal fan and reducing the noise of the centrifugal fan, thereby achieving high heat dissipation and low noise performance of the air cooling system. It can provide sufficient heat dissipation capacity for electronic equipment, so that the performance of electronic equipment can be well released, which is conducive to improving the performance of electronic equipment and the noise reduction experience. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] FIG1 is a schematic structural diagram of an electronic device provided in an embodiment of the present application;

[0023] FIG2 is a schematic diagram of the cross-sectional structure of the electronic device along plane AA in FIG1 ;

[0024] FIG3 is a schematic structural diagram of an air cooling system in an electronic device provided in an embodiment of the present application;

[0025] FIG4 is a schematic diagram of the internal structure of a centrifugal fan in the related art;

[0026] FIG5 is a schematic structural diagram of a centrifugal fan provided in an embodiment of the present application;

[0027] FIG6 is a schematic diagram of the disassembled structure of a centrifugal fan provided in an embodiment of the present application;

[0028] FIG7 is a schematic structural diagram of an impeller provided in an embodiment of the present application;

[0029] FIG8 is a schematic diagram of the internal structure of a centrifugal fan provided in an embodiment of the present application;

[0030] FIG9 is a front view schematic diagram of the internal structure of a centrifugal fan provided in an embodiment of the present application;

[0031] FIG10 is a simulation diagram of the velocity field of a centrifugal fan in the related art;

[0032] FIG11 is a velocity field simulation diagram of a centrifugal fan provided in an embodiment of the present application.

[0033] Explanation of Reference Numerals: 100 - electronic device; 101 - first housing; 101a - housing cover; 101b - bottom housing; 1011 - vent; 102 - second housing; 103 - heating element; 104 - air cooling system; 10 - centrifugal fan; 11 - housing; 11a - bottom wall; 11b - side wall; 11c - top wall; 111 - cavity; 112 - inner side surface; 1121 - raised surface; 1121a - first curved surface; 1121b - first plane; 1122 - first guide surface; 1123 - second guide surface; 1123a - second curved surface; 1123b - second plane; 113 - air inlet; 114 - air outlet; 115 - air flow channel; 12 - impeller; 121 - circumferential side surface; 122 - disc; 123 - Fan blades; 20 - Heat dissipation device; 30 - Heat transfer device; 105 - Circuit board; 106 - Key structure; 107 - Touch area; 108 - Display screen; 109 - Accommodation cavity; 110 - Power button. DETAILED DESCRIPTION

[0034] The terms used in the implementation section of this application are only used to explain the specific embodiments of this application and are not intended to limit this application.

[0035] An electronic device provided in an embodiment of the present application may include, but is not limited to, mobile phones, tablet computers, laptop computers, two-in-one tablet computers / computers, ultra-mobile personal computers (UMPCs), handheld computers, walkie-talkies, netbooks, POS machines, personal digital assistants (PDAs), wearable devices, virtual reality devices (VR), augmented reality devices (AR), routers, power banks, mobile Wi-Fi, vehicle-mounted devices, and other electronic devices with heat dissipation requirements.

[0036] For example, in the embodiment of the present application, the electronic device provided in the embodiment of the present application is described by taking the electronic device as a laptop computer as an example.

[0037] FIG1 is a schematic structural diagram of an electronic device provided in an embodiment of the present application.

[0038] As shown in Figure 1, the electronic device 100 may include two shells, for example, a first shell 101 and a second shell 102. The electronic device 100 may also include a rotating mechanism (not shown in the figure), and the first shell 101 and the second shell 102 are respectively located on both sides of the rotating mechanism. The first shell 101 and the second shell 102 can be respectively connected to the rotating mechanism. The rotating mechanism can realize the rotation coordination of the first shell 101 and the second shell 102, thereby realizing the opening and closing of the laptop computer.

[0039] The electronic device 100 may further include a button structure 106 . The button structure 106 may be provided on the first housing 101 . The button structure 106 may be used to identify user operation information and implement human-computer interaction with the user.

[0040] It should be understood that the button structure 106 may be a protruding button structure, or the button structure 106 may be a virtual button, etc.

[0041] The first housing 101 may further include a touch area 107 , which may be used to identify user operation information, such as gesture information, to enrich the operation experience of the electronic device 100 .

[0042] The first housing 101 may further include a power button 110 , which is used to turn the electronic device on and off.

[0043] The electronic device 100 may further include a display screen 108 . The display screen 108 may be provided on the second housing 102 . The display screen 108 is used to display images and the like.

[0044] Of course, in some other examples, the display screen 108 can also be used to identify the user's operation information, such as the user's operation position information, gesture information, etc.

[0045] The display screen 108 may include a display panel, which may be a liquid crystal display (LCD), an organic light-emitting diode (OLED), an active-matrix organic light-emitting diode or an active-matrix organic light-emitting diode (AMOLED), a flexible light-emitting diode (FLED), a mini-LED, a micro-LED, a Micro-OLED, a quantum dot light-emitting diode (QLED), etc.

[0046] The first housing 101 may have a receiving cavity, and the structural components of the electronic device may be accommodated in the receiving cavity. In some examples,

[0047] The second housing 102 may also have a receiving cavity, and the receiving cavity of the second housing 102 may also be used to accommodate structural components of the electronic device.

[0048] FIG2 is a schematic diagram of the cross-sectional structure of the electronic device along plane AA in FIG1 .

[0049] As shown in Figure 2, taking the first shell 101 as an example, the first shell 101 may include a bottom shell 101b and a shell cover 101a. The shell cover 101a may be covered on the bottom shell 101b. The shell cover 101a and the bottom shell 101b together form a accommodating cavity 109, and the structural components of the electronic device are fixed in the accommodating cavity 109.

[0050] The button structure 106 , the touch area 107 , the power button 110 , etc. may be respectively located on the housing cover 101 a of the first housing 101 .

[0051] Exemplarily, the electronic device 100 may further include a processor (not shown in the figure), for example, the processor may include a central processing unit (CPU), an application processor (AP), a modem processor, a graphics processing unit (GPU), an image signal processor (ISP), a controller, a video codec, a digital signal processor (DSP), a baseband processor, and / or a neural-network processing unit (NPU), etc.

[0052] The processor can generate operation control signals based on the instruction opcode and timing signals to complete the control of instruction fetching and execution. The processor can also be provided with a memory for storing instructions and data.

[0053] The processor may include one or more interfaces, and the processor can be connected to other components of the electronic device 100 through the interface, for example, to realize the connection between the processor and sensors, audio modules, display screens, cameras and other modules of the electronic device 100.

[0054] Exemplarily, the processor may include a universal serial bus (USB) interface (not shown in the figure). The USB interface may be provided on the first housing 101 and may be used to connect the electronic device and peripheral devices.

[0055] For example, the USB interface can be used to connect a charger to charge the electronic device 100. The USB interface can also be used to connect other electronic devices, such as storage devices, to achieve data transmission between the electronic device 100 and other electronic devices.

[0056] Of course, in some other examples, the USB interface can also be used to connect other electronic devices, such as external projection equipment, VR equipment, etc.

[0057] The electronic device 100 may further include a battery, a charging module, and a power management module. The charging module is configured to receive a charging input from a charger to charge the battery. For example, the charging management module may receive a charging input from the charger via a USB interface.

[0058] The power management module is used to connect the battery, the charging management module, and the processor. While the charging management module charges the battery, it can also power the electronic device 100 through the power management module. The power management module receives input from the battery and / or the charging management module and can power the processor, memory, display screen, camera, etc.

[0059] The power management module can also be used to monitor the battery, such as monitoring the battery capacity, battery cycle number, battery health status (leakage, impedance) and other parameters.

[0060] The electronic device 100 may further include a camera (not shown in the figure), through which a camera function may be realized.

[0061] The electronic device 100 may further include an audio module, a speaker, a microphone, etc. (not shown in the figure) to implement the audio function of the electronic device 100. Among them, the audio module is used to convert digital audio information into analog audio signal output, and is also used to convert analog audio input into digital audio signals. The audio module can also be used to encode and decode audio signals. In some embodiments, the audio module can be provided in the processor, or some functional modules of the audio module can be provided in the processor.

[0062] A speaker, also known as a "horn," is used to convert audio electrical signals into sound signals. Electronic device 100 can output sound through the speaker to play the sound. A microphone, also known as a "microphone" or "microphone," is used to convert sound signals into electrical signals. Electronic device 100 can receive external sound through the microphone.

[0063] It is understood that the structures illustrated in the embodiments of the present application do not constitute specific limitations on the electronic device. In other embodiments of the present application, the electronic device may include more or fewer structural components than shown, or combine or split certain structural components, or arrange the structural components differently.

[0064] For example, the electronic device 100 may further include a pressure sensor, a touch sensor, an antenna, a communication module, and the like.

[0065] Continuing with FIG2 , the electronic device may further include a circuit board 105 , on which a heating element 103 may be disposed, and both the heating element 103 and the circuit board 105 may be fixed within the accommodating cavity. The heating element 103 may be any device that generates heat during operation and requires heat dissipation, such as the aforementioned processor, battery, etc.

[0066] It is understandable that the electronic device 100 may include one or more heating devices 103 , and the specific number and type of the heating devices 103 may be selected and set according to needs.

[0067] To dissipate heat from the heating element 103 , air cooling may be used to dissipate heat from the electronic device 100 . For example, as shown in FIG. 2 , the electronic device may further include an air cooling system 104 , which may dissipate heat from the electronic device.

[0068] Among them, the air cooling system 104 can include a centrifugal fan 10, which can be set adjacent to the heating device 103. The centrifugal fan 10 can accelerate the flow of air in the surrounding environment (such as in the accommodating cavity), quickly exchange heat with the heating device 103, and achieve a heat dissipation effect on the heat of the heating device 103.

[0069] For example, the centrifugal fan 10 may be electrically connected to the circuit board 105 , and the circuit board 105 may be capable of driving and controlling the centrifugal fan 10 .

[0070] In some examples, a vent 1011 may be further provided on the first shell 101. For example, a vent 1011 may be provided on the side wall of the bottom shell 101b. The vent 1011 may pass through the side wall of the bottom shell 101b so that the vent 1011 can be connected to the accommodating cavity. The accommodating cavity and the external environment of the electronic device are connected through the vent 1011, thereby realizing air circulation between the inside and outside of the electronic device and further improving the heat dissipation effect.

[0071] It should be noted that Figure 2 shows only one vent 1011 on the first housing 101. To achieve air circulation inside and outside the electronic device, the first housing 101 may have multiple vents 1011, for example, two, one of which may serve as an air inlet and the other as an air outlet.

[0072] FIG3 is a schematic structural diagram of an air cooling system in an electronic device provided in an embodiment of the present application.

[0073] As shown in FIG. 3 , the air cooling system 104 may further include a heat dissipation device 20 and a heat transfer device 30 , wherein the heat transfer device 30 may be used to achieve high-performance heat transfer between the heating element 103 and the heat dissipation device 20 .

[0074] In some examples, the heat transfer device 30 may be a device with high heat transfer performance, such as a vapor chamber (VC) or a heat pipe.

[0075] The heat sink 20 can be used to provide a heat exchange location for the centrifugal fan 10 and the heat transfer device 30 to achieve a more enhanced heat exchange effect. In some examples, the heat sink 20 can be an enhanced heat exchange device such as a plate-fin straight heat sink or a pin-fin heat sink.

[0076] The heat dissipation device 20 can be located at the air outlet 114 of the centrifugal fan 10, and the heat transfer device 30 can be located between the heat dissipation device 20 and the heating device 103. The heat transfer device 30 can be in thermal contact with the heat dissipation device 20 and the heating device 103 respectively, so as to realize the heat transfer between the heating device 103, the heat transfer device 30 and the heat dissipation device 20.

[0077] The heat generated by the heating device 103 can be efficiently conducted to the heat sink 20 through the heat transfer device 30. When the centrifugal fan 10 is running, it can accelerate the flow of cold air, so that a high-speed airflow can be generated at the air outlet 114, and the high-speed airflow can pass through the heat sink 20, thereby achieving heat exchange with the heat sink 20, absorbing the heat in the heat sink 20 to form a hot air flow, and the hot air flow can bring the heat to the environment outside the electronic device. For example, the hot air flow can be discharged to the outside of the electronic device through the vents on the bottom shell, thereby achieving heat dissipation of the electronic device.

[0078] As the performance demands on electronic devices continue to increase, power consumption and heat dissipation are deteriorating. Heat generated by electronic devices needs to be dissipated to the environment in a timely manner. The heat dissipation performance of air-cooled systems is heavily dependent on the fan, making high heat dissipation efficiency a key requirement for centrifugal fans. Furthermore, as electronic devices become increasingly integrated into our daily lives, fan noise significantly impacts the user experience. Therefore, improving the performance and reducing the noise of centrifugal fans are key to enhancing the capabilities of air-cooled systems.

[0079] FIG4 is a schematic diagram of the internal structure of a centrifugal fan in the related art.

[0080] As shown in Figure 4, a common centrifugal fan 200 may include fan blades 201 and a volute 202, the volute 202 having a cavity 202a, the fan blades 201 being arranged in the cavity 202a, and there being a gap between the fan blades 201 and the inner surface of the side wall of the volute 202, thereby forming an air flow channel 203, that is, there is an air flow channel between the fan blades 201 and the inner surface of the side wall of the volute 202, and an air inlet (not shown in the figure) and an air outlet 202b may be respectively opened on the volute 202, and the air inlet and the air outlet 202b may be respectively connected to the air flow channel 203.

[0081] The fan blades 201 are rotatably disposed within the cavity 202a of the volute 202. The rotation of the fan blades 201 allows the airflow to be quickly discharged from the air outlet through the air inlet and air flow channel 203, thereby improving the flow of air in the environment through the centrifugal fan 200. The arrows in Figure 4 indicate the direction of air flow when the fan blades 201 rotate counterclockwise.

[0082] To improve the performance of centrifugal fan 200, a raised tongue 204 may be provided on the inner surface of the sidewall of volute 202. Tongue 204 may be located on the inner surface of the sidewall near air outlet 202b. Because tongue 204 is formed on the inner surface of the sidewall, the distance between the outer surface of tongue 204 and the peripheral surface of blade 201 is narrower. In other words, tongue 204 may be the portion of the inner surface of the sidewall of volute 202 closest to blade 201, narrowing the airflow channel 203 between tongue 204 and blade 201.

[0083] From the position of the volute tongue 204 to the air outlet 202b, there is an area in the air flow channel 203 that gradually widens from narrow, such as the pressurized area 202c in Figure 4. When the air flow passes through the area from narrow to wide, the air flow can be pressurized to increase the air output of the fan.

[0084] Moreover, the raised volute tongue 204 can also form a physical partition between the pressurized area 202c and the air outlet 202b area, preventing the air from the fan outlet 202b from being brought into the pressurized area 202c by the rotation of the fan blades 201, which would cause a decrease in the fan's air outlet performance.

[0085] Extensive structural design experience has shown that the smaller the gap between the volute tongue and the side surface of the fan blade, the higher the air output of the centrifugal fan 200 and the better the heat dissipation performance. However, the narrower the airflow channel width at the volute tongue, the more severe pressure pulsations will form in the rapidly narrowing channel as each fan blade rotates and passes through it, generating a large amount of noise. Therefore, the smaller the gap between the volute tongue and the side surface of the fan blade, the louder the noise of the centrifugal fan. It is difficult to ensure that the heat dissipation performance of the centrifugal fan can be improved while also taking into account the noise level.

[0086] Based on this, the embodiments of the present application provide a centrifugal fan that can achieve the goal of noise reduction while improving the centrifugal fan's air output performance. This can also ensure that noise reduction is achieved while improving the centrifugal fan's heat dissipation performance and reducing the noise. This centrifugal fan can provide sufficient heat dissipation capacity for electronic devices to support the unleashing of electronic device performance, thereby improving the performance of electronic devices and providing users with a good heat dissipation and noise reduction experience.

[0087] FIG5 is a schematic structural diagram of a centrifugal fan provided in an embodiment of the present application.

[0088] As shown in Figure 5, the centrifugal fan 10 may include a casing 11 and an impeller 12, wherein the casing 11 serves as the main load-bearing structural component of the centrifugal fan 10, and the casing 11 may have a cavity 111 for accommodating the impeller 12, or may also be used to accommodate other structural components of the centrifugal fan 10.

[0089] The shell 11 is provided with an air inlet 113 and an air outlet 114 , which can be through holes on the shell 11 respectively. The air inlet 113 can be connected to the cavity 111 in the shell 11 , and the air outlet 114 can also be connected to the cavity 111 in the shell 11 .

[0090] It should be noted that, in the embodiment of the present application, there is no limitation on the molding material of the shell 11. For example, the molding material of the shell 11 can be plastic, metal, alloy, etc.

[0091] There is no limitation on the assembly and molding method of the housing 11. For example, the housing 11 can be an integrally formed structural component, such as the housing 11 can be an integrally formed structural component by injection molding or the like.

[0092] Alternatively, in some examples, the housing 11 may be formed by assembling separate structural parts. The specific material and assembly method can be selected and set according to actual needs.

[0093] In the embodiment of the present application, the shell 11 is formed by assembling split structural parts as an example. The shell 11 formed by assembling split structural parts has high design flexibility, which is conducive to reducing the difficulty of production design and is easy to implement.

[0094] FIG6 is a schematic diagram of the disassembled structure of a centrifugal fan provided in an embodiment of the present application.

[0095] Exemplarily, in combination with Figures 5 and 6, the shell 11 may include a bottom wall 11a, a side wall 11b and a top wall 11c, wherein the top wall 11c and the bottom wall 11a may be arranged opposite to each other, and the side wall 11b may be located between the bottom wall 11a and the top wall 11c, so that the top wall 11c, the side wall 11b and the bottom wall 11a can together form a cavity 111 of the shell 11, and the inner surface of the side wall 11b (the side facing the box body) can form an inner side surface 112 of the cavity 111.

[0096] Among them, the bottom wall 11a and the top wall 11c can be planes respectively, the side wall 11b is located between the bottom wall 11a and the top wall 11c, and the side wall 11b can have a certain extension height in the direction perpendicular to the bottom wall 11a and the top wall 11c to ensure that the bottom wall 11a, the top wall 11c and the side wall 11b can form a cavity 111.

[0097] An air inlet 113 may be provided on at least one of the top wall 11c or the bottom wall 11a, and an air outlet 114 may be provided on the side wall 11b, that is, the air outlet 114 is located between the top wall 11c and the bottom wall 11a.

[0098] It should be noted that there may be only one air inlet 113 . For example, as shown in FIG. 5 and FIG. 6 , a through hole may be opened on the top wall 11 c to form the air inlet 113 .

[0099] Of course, in some other examples, there may be multiple air inlets 113 , for example, there may be two air inlets. For example, through holes may be respectively opened on the top wall 11 c and the bottom wall 11 a to form two air inlets.

[0100] In the embodiment of the present application, an air inlet 113 is provided on the top wall 11 c as an example for description.

[0101] The impeller 12 is rotatably disposed in a cavity 111 surrounded by a bottom wall 11a, side walls 11b and a top wall 11c. The impeller 12 can rotate around an axis o (as shown in FIG. 7 ), with the direction parallel to the axis being the axial direction of the impeller 12.

[0102] The impeller 12 may be circular in shape, and its axis may be a straight line passing through the center of the impeller 12 and perpendicular to the impeller 12. In the embodiment of the present application, the radial direction is a direction parallel to the diameter / radius of the impeller 12, and the axial direction of the impeller 12 may be perpendicular to the radial direction. It is understood that the radial direction may be any direction passing through the center of the impeller 12 and perpendicular to the axial direction of the impeller 12 (for example, the y direction in FIG. 7 ), and the radial direction may include multiple directions.

[0103] The air inlet 113 on the housing 11 may be located on one side of the impeller 12 along the axial direction, and the air outlet 114 may be located on one side of the impeller 12 along the radial direction (see FIG. 5 ).

[0104] FIG7 is a schematic structural diagram of an impeller provided in an embodiment of the present application.

[0105] As shown in Figure 7, the impeller 12 may include a circumferential side surface 121. The circumferential side surface 121 may be the outermost surface of the impeller 12 in the circumferential direction, or it can be understood as a circular surface formed by the circumferential side surface 121 with the axis o of the impeller 12 as the center line and the radius of the impeller 12 as the radius.

[0106] The impeller 12 may include a wheel disc 122 and a plurality of blades 123 . The plurality of blades 123 may be fixed on the wheel disc 122 . The wheel disc 122 may drive the plurality of blades 123 to rotate, thereby rotating the impeller 12 .

[0107] The plurality of blades 123 may be arranged in a circular array around the axis o on the wheel disc 122 and may be arranged at equal intervals. The plurality of blades 123 may help increase the air volume of the centrifugal fan 10 and thereby improve the heat dissipation performance of the centrifugal fan 10.

[0108] The wheel disc 122 may be circular in shape, the blades 123 may be approximately in the form of an arc-shaped plate, one end of the plurality of blades 123 may be fixed on the wheel disc 122 , and the other end face may be flush with the peripheral side surface 121 of the impeller 12 .

[0109] The specific number of the fan blades 123 is not limited in the embodiment of the present application and can be selected and set according to actual needs.

[0110] The impeller 12 may further include an annular reinforcement 124, which is fixed to one end of the plurality of blades 123 facing away from the wheel disc 122. The reinforcement 124 connects and fixes the plurality of blades 123 into an integral structural member, thereby increasing the strength of the blades 123 and improving the stability of the entire impeller 12. The outer circumferential surface of the annular reinforcement 124 may be flush with the circumferential surface 121 of the impeller 12. In some examples, the outer circumferential surface of the annular reinforcement 124 and the other end surfaces of the plurality of blades 123 facing away from the wheel disc 122 may together form the circumferential surface 121 of the impeller 12.

[0111] The centrifugal fan 10 may further include a driving structure (not shown in the figure). For example, the driving structure may be fixed on the wheel 122. The driving structure is connected to the wheel 122 and drives the wheel 122 to rotate, thereby driving the plurality of blades 123 to rotate together through the wheel 122.

[0112] Figure 8 is a schematic diagram of the internal structure of a centrifugal fan provided in an embodiment of the present application. It should be noted that the top wall of the centrifugal fan is not shown in Figure 8.

[0113] As shown in Figure 8, the impeller 12 is rotatably assembled in the cavity 111, and there is a gap between the peripheral side surface 121 of the impeller 12 and the inner side surface 112 of the cavity 111 (that is, the inner surface of the side wall 11b) to form an air flow channel 115. The air flow channel 115 is respectively connected to the air outlet 114 on the side wall 11b and the air inlet on the top wall.

[0114] The rotation of the impeller 12 can accelerate the flow of air in the air flow channel 115 , so that the air outside the cavity 111 can quickly enter through the air inlet and be discharged from the air outlet 114 at a high speed after passing through the air flow channel 115 .

[0115] The impeller 12 may rotate in a clockwise direction, or may rotate in a counterclockwise direction.

[0116] FIG9 is a front schematic diagram of the internal structure of a centrifugal fan provided in an embodiment of the present application.

[0117] As shown in FIG. 9 , the inner side surface 112 of the cavity 111 may include a convex surface 1121 , a first guide surface 1122 , and a second guide surface 1123 .

[0118] One end of the raised surface 1121 is connected to one end of the air outlet 114, and the other end of the raised surface 1121 is connected to one end of the first guide surface 1122. An intersection line can be formed at the position where the raised surface 1121 and the first guide surface 1122 are connected (refer to the intersection line L1 in Figure 8).

[0119] The other end of the first guide surface 1122 is connected to one end of the second guide surface 1123 , where the first guide surface 1122 and the second guide surface 1123 are connected to form an intersection line (see intersection line L2 in FIG8 ). The other end of the second guide surface 1123 is connected to the other end of the air outlet 114 .

[0120] The first distance is the radial distance between the intersection line L1 between the raised surface 1121 and the first guide surface 1122 and the circumferential side surface 121 of the impeller 12. A radial line (a straight line along the radial direction and passing through the center of the circle) can be drawn to intersect the axis o and the intersection line L1, respectively. For example, the radial line can be perpendicular to the axis o and the intersection line L1. The first distance can be the length of the line segment between the intersection point of the radial line with the circumferential side surface 121 of the impeller 12 and the intersection point of the radial line with the intersection line L1.

[0121] For example, Figure 9 is a front view of the centrifugal fan 10, taking the projection of the structure of the centrifugal fan onto the bottom wall 11a as an example, wherein the projection of the axis of the impeller 12 on the bottom wall 11a is o1, the projection of the intersection line L1 of the raised surface 1121 and the first guide surface 1122 on the bottom wall 11a is point o2, the radial line passing through the projection point o1 connecting the axis and the projection o2 of the intersection line L1 is y1, and the first distance d1 is the length of the line segment between the intersection point of the radial line y1 and the circumferential surface 121 of the impeller 12 and the intersection point o2 of the radial line y1 and the intersection line.

[0122] Correspondingly, the distance in the radial direction between the intersection line L2 of the first guide surface 1122 and the second guide surface 1123 and the circumferential side surface 121 of the impeller 12 is taken as the second distance, wherein radial lines can be made that intersect with the axis o and the intersection line L2 respectively. For example, the radial line can be perpendicular to the axis o and the intersection line L2, and the second distance can be the length of the line segment between the intersection point of the radial line with the circumferential side surface 121 of the impeller 12 and the intersection point of the radial line with the intersection line L2.

[0123] For example, referring to Figure 9, taking the projection of the structure of the centrifugal fan onto the bottom wall 11a as an example, the projection of the intersection line of the first guide surface 1122 and the second guide surface 1123 on the bottom wall 11a is point o3, the radial line passing through the projection point o1 of the connecting axis and the projection point o3 of the intersection line L2 is y2, and the second distance d2 is the length of the line segment between the intersection point of the radial line y2 and the circumferential surface 121 of the impeller 12 and the intersection point of the radial line y2 and the projection o3 of the intersection line.

[0124] It can be understood that the radial line y1 and the radial line y2 correspond to two different radial directions respectively, and the two radial directions may intersect with each other, with a certain angle between them.

[0125] The second distance d2 is smaller than the first distance d1, that is, the distance between the intersection line L2 of the second guide surface 1123 and the first guide surface 1122 and the peripheral side surface 121 is smaller than the distance between the intersection line L1 of the convex surface 1121 and the first guide surface 1122 and the peripheral side surface 121. It is understood that the convex surface 1121 can be formed as a protrusion on the inner side surface 112 of the cavity 111. The convex surface 1121 protrudes toward the interior of the cavity 111, causing the airflow channel 115 to experience a sudden change in width (width in the radial direction) at the location of the convex surface 1121. That is, in the direction from the convex surface 1121 to the second guide surface 1123, the airflow channel 115 undergoes a change in width from wide to narrow once at the location of the convex surface 1121, and the airflow channel 115 undergoes a second change in width from wide to narrow at the location of the first guide surface 1122.

[0126] As shown in Figures 8 and 9, from the end where the second guide surface 1123 is connected to the first guide surface 1122 to the end where the second guide surface 1123 is connected to the air outlet 114, the distance in the radial direction between the second guide surface 1123 and the peripheral side surface 121 of the impeller 12 can gradually increase. That is, starting from the end where the second guide surface 1123 is connected to the first guide surface 1122 (such as the intersection line L2), the air flow channel 115 has an area where the width gradually changes from narrow to wide. This part of the area can be used as a pressurized area of ​​the centrifugal fan, such as the pressurized area 10a shown in Figure 9. When the air flow passes through this part of the area where the width gradually changes from narrow to wide, the air flow is pressurized to increase the air output of the fan.

[0127] Continuing with FIG9 , the minimum radial distance between the inner surface 112 of the cavity 111 and the inner surface of the impeller 12 is located at the intersection of the second guide surface 1123 and the first guide surface 1122. The narrowest width of the airflow channel 115 is located at the intersection of the second guide surface 1123 and the first guide surface 1122. The narrowest position of the airflow channel 115 is relatively far from the raised surface 1121 (the point of sudden change in size). Compared with related technologies, under the same noise requirements (such as when the spacing between the raised surface and the peripheral side surface is consistent), the second distance d2 can be relatively smaller, which can also provide the centrifugal fan with a stronger pressurization capacity and a stronger air outlet performance, thereby improving the heat dissipation performance of the centrifugal fan and ensuring that the noise does not deteriorate while improving the heat dissipation performance.

[0128] Moreover, since the second distance d2 is smaller than the first distance d1, the width change between the raised surface 1121 and the peripheral surface 121 of the impeller 12 has a relatively small effect on the performance of the centrifugal fan 10. Therefore, compared with the related art, the first distance d1 can be relatively larger, reducing the cross-sectional area change rate from the air outlet 114 to the raised surface 1121. When the impeller 12 rotates and passes through the raised surface 1121, the size mutation at this position can be reduced to a certain extent, so that the pressure pulsation generated at the raised surface 1121 is weakened, thereby reducing noise and achieving noise reduction of the centrifugal fan. To a certain extent, it is possible to achieve a balance between fan performance improvement and noise reduction, so as to achieve both centrifugal fan performance improvement and noise reduction at the same time.

[0129] Continuing to refer to Figure 9, from the end where the first guide surface 1122 is connected to the raised surface 1121 to the end where the first guide surface 1122 is connected to the second guide surface 1123, the distance in the radial direction between the first guide surface 1122 and the peripheral side surface 121 of the impeller 12 gradually decreases, that is, a channel with a gradually decreasing width is formed in the direction from the raised surface 1121 to the second guide surface 1123.

[0130] That is to say, a gradually shrinking channel is set between the raised surface 1121 and the pressurized area formed by the second guide surface 1123 and the peripheral side surface 121, which facilitates the reduction of the second distance compared to the first distance, and has a higher transition smoothness, reduces the noise caused by the width change, etc., which is beneficial to further reduce the noise while improving the performance of the centrifugal fan 10.

[0131] For example, from one end where the first guide surface 1122 is connected to the raised surface 1121 to the end where the first guide surface 1122 is connected to the second guide surface 1123, the distance in the radial direction between the first guide surface 1122 and the peripheral side surface 121 of the impeller 12 can gradually decrease in a monotonically decreasing manner. Under the condition of achieving a decreasing distance between the first guide surface 1122 and the peripheral side surface 121 of the impeller 12, it is beneficial to reduce the structural design difficulty of the first guide surface 1122 and facilitate design and production implementation.

[0132] The first guide surface 1122 can be an arc surface that bends toward the impeller 12. The first guide surface 1122 is an arc surface with good smoothness, which is conducive to the smooth transition of the airflow in the gradually shrinking channel formed between the first guide surface 1122 and the peripheral side surface 121. It can reduce the impact of the change in width size on the airflow, which is conducive to improving the air outlet and noise reduction performance of the centrifugal fan 10.

[0133] Continuing to refer to Figure 9, the raised surface 1121 may include a first curved surface 1121a and a first plane 1121b, wherein one end of the first curved surface 1121a may be connected to the first guide surface 1122, and the first curved surface 1121a may be a curved surface convex toward the impeller 12. The first curved surface 1121a and the first guide surface 1122 are connected to form a curved surface, which is beneficial to improving the smoothness of the connection between the first curved surface 1121a and the curved first guide surface 1122, and reducing the impact of width size changes on airflow.

[0134] The intersection line of the convex surface 1121 and the first flow-guiding surface 1122 is also the intersection line of the convex first curved surface 1121a and the concave first flow-guiding surface 1122. The first curved surface 1121a and the first flow-guiding surface 1122 are connected to form a curved surface. The straight line passing through the concave-convex inflection point of the curved surface curve and perpendicular to the radial direction is the intersection line of the first curved surface 1121a and the first flow-guiding surface 1122. As shown in FIG9, the projection of the curved surface formed by the convex first curved surface 1121a and the concave first flow-guiding surface 1122 on the bottom wall 11a is the curved surface. The concave-convex inflection point of the curve is point o2. The straight line passing through the inflection point o2 and perpendicular to the radial direction is the intersection line of the convex surface 1121 and the first flow-guiding surface 1122 (such as L1 in FIG8).

[0135] The other end of the first curved surface 1121a can be connected to one end of the first plane 1121b, and the other end of the first plane 1121b can be connected to one end of the air outlet 114. The other end of the first curved surface 1121a and one end of the first plane 1121b can achieve a smooth transition connection.

[0136] The first plane 1121b can be an inclined plane. Specifically, from the end of the first plane 1121b connected to the first curved surface 1121a to the end of the first plane 1121b connected to the air outlet 114, the first plane 1121b is inclined toward the outside of the cavity 111, so that the air outlet 114 can be open, which can further increase the opening of the air outlet 114 and help improve the air outlet performance of the centrifugal fan.

[0137] Continuing with FIG9 , the second guide surface 1123 may include a second curved surface 1123a and a second flat surface 1123b. One end of the second curved surface 1123a is connected to the first guide surface 1122, and the other end of the second curved surface 1123a is connected to one end of the second flat surface 1123b. The other end of the second curved surface 1123a and one end of the second flat surface 1123b can achieve a smooth transition. The other end of the second flat surface 1123b is connected to the other end of the air outlet 114. Starting from the end where the second guide surface 1123 connects to the first guide surface 1122, the width of the airflow channel 115 gradually increases from narrow to wide, which can serve as a pressurized area. The portion where the second guide surface 1123 connects to the first guide surface 1122 forms the second curved surface 1123a. This allows for smoother air flow within the pressurized area, reduces gas energy dissipation, facilitates air pressurization, and improves the air output performance of the centrifugal fan.

[0138] In addition, the portion where the second guide surface 1123 is connected to the air outlet 114 is formed as the second plane 1123 b , which is beneficial for expanding the opening of the air outlet 114 and improving the air outlet performance of the centrifugal fan.

[0139] Among them, the first guide surface 1122 and the second guide surface 1123 are connected to form an arc surface that bends toward the impeller 12, which has good smoothness, so that the airflow can smoothly transition between the gradually narrowing channel formed by the first guide surface 1122 and the peripheral side surface 121 to the pressurized area channel formed by the second guide surface 1123 and the peripheral side surface 121, further reducing the impact of the width size change on the airflow, and can also ensure the pressurization effect of the airflow, which is beneficial to improving the air outlet and noise reduction performance of the centrifugal fan.

[0140] FIG10 is a velocity field simulation diagram of a centrifugal fan in the related art, and FIG11 is a velocity field simulation diagram of a centrifugal fan provided in an embodiment of the present application.

[0141] The velocity fields of the centrifugal fan 200 in the related art mentioned above in this embodiment and the centrifugal fan 10 in the embodiment of the present application are simulated, wherein the gap between the volute tongue and the peripheral side of the fan blade of the centrifugal fan 200 in the related art is equal to the first distance d1 of the centrifugal fan 10 in the embodiment of the present application.

[0142] As shown in Figures 10 and 11, under the condition of the same impeller speed, the centrifugal fan 200 in the related art has an air output of 2.56 cfm, where cfm is the unit of air output, meaning air volume - cubic feet per minute (cubic feet per minute), which refers to the volume of air passing through the fan outlet (or inlet) cross-section per unit time.

[0143] The centrifugal fan 10 of the embodiment of the present application has an air output of 2.84 cfm. That is, under the condition of the same rotational speed, the air output of the centrifugal fan of the embodiment of the present application is increased by 11%.

[0144] The maximum air velocity of the centrifugal fan 200 in the related art is 23.28 m / s, where m / s is a unit of wind speed, meaning meters per second, and refers to the distance the wind travels. The maximum air velocity of the centrifugal fan 10 in the embodiment of the present application is 23.19 m / s, which is comparable in wind speed and produces substantially equivalent noise.

[0145] In summary, the centrifugal fan provided in the embodiment of the present application can achieve a significant increase in air output under the condition of the same noise requirement, and accordingly, can achieve a significant noise reduction effect under the condition of the same air output requirement.

[0146] It should be noted that the numerical values ​​and numerical ranges involved in the embodiments of the present application are approximate values ​​and may have a certain range of errors. Those skilled in the art may consider such errors to be negligible.

[0147] In the description of the embodiments of the present application, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense. For example, it can be a fixed connection, or it can be an indirect connection through an intermediate medium, or it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the embodiments of the present application can be understood according to the specific circumstances. The terms "first", "second", "third", "fourth", etc. (if any) are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence.

[0148] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the embodiments of the present application, rather than to limit them. Although the embodiments of the present application have been described in detail with reference to the aforementioned embodiments, ordinary technicians in this field should understand that they can still modify the technical solutions recorded in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. These modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A centrifugal fan, characterized in that: The invention comprises a housing (11) and an impeller (12), wherein the housing (11) has a cavity (111), the housing (11) has an air inlet (113) and an air outlet (114), the impeller (12) is rotatably arranged in the cavity (111), and a gap is provided between a peripheral side surface (121) of the impeller (12) and an inner side surface (112) of the cavity (111) to form an air flow channel (115), and the air outlet (114) and the air inlet (113) are respectively connected to the air flow channel (115); The inner side surface (112) of the cavity (111) comprises a convex surface (1121), a first flow guide surface (1122) and a second flow guide surface (1123) which are connected in sequence; the convex surface (1121) is connected to one end of the air outlet (114), and the second flow guide surface (1123) is connected to the other end of the air outlet (114); and from the end where the second flow guide surface (1123) is connected to the first flow guide surface (1122) to the end where the second flow guide surface (1123) is connected to the air outlet (114), the distance between the second flow guide surface (1123) and the peripheral side surface (121) of the impeller (12) in the radial direction of the impeller (12) gradually increases; The distance in the radial direction between the intersection line of the raised surface (1121) and the first guide surface (1122) and the peripheral side surface (121) of the impeller (12) is a first distance, and the distance in the radial direction between the intersection line of the first guide surface (1122) and the second guide surface (1123) and the peripheral side surface (121) of the impeller (12) is a second distance, and the second distance is smaller than the first distance.

2. The centrifugal fan according to claim 1, characterized in that: From one end where the first guide surface (1122) is connected to the raised surface (1121) to one end where the first guide surface (1122) is connected to the second guide surface (1123), the distance in the radial direction between the first guide surface (1122) and the peripheral side surface (121) of the impeller (12) gradually decreases.

3. The centrifugal fan according to claim 2, characterized in that: From one end where the first guide surface (1122) is connected to the raised surface (1121) to one end where the first guide surface (1122) is connected to the second guide surface (1123), the distance in the radial direction between the first guide surface (1122) and the peripheral side surface (121) of the impeller (12) decreases monotonically.

4. The centrifugal fan according to claim 3, characterized in that: The first flow guide surface (1122) is a curved surface that curves toward the impeller (12); The convex surface (1121) comprises a first arcuate surface (1121a), and the first arcuate surface (1121a) is an arcuate surface convex toward the cavity (111); One end of the first arcuate surface (1121a) is connected to the first guide surface (1122) to form a curved surface, and the intersection line of the convex surface (1121) and the first guide surface (1122) is a straight line passing through the concave and convex inflection point of the curve of the curved surface and perpendicular to the radial direction.

5. The centrifugal fan according to claim 4, characterized in that: The second flow guiding surface (1123) comprises a second curved surface (1123a) and a second plane (1123b) which are connected to each other; the second curved surface (1123a) is connected to the first flow guiding surface (1122); and the second plane (1123b) is connected to the air outlet (114).

6. The centrifugal fan according to claim 5, characterized in that: The second arcuate surface (1123a) and the first flow guide surface (1122) are connected to form an arcuate surface that curves toward the impeller (12).

7. The centrifugal fan according to any one of claims 4 to 6, characterized in that: The convex surface (1121) further comprises a first plane (1121b) connected to the other end of the first arc-shaped surface (1121a), and the first plane (1121b) is connected to the air outlet (114); From an end of the first plane (1121b) connected to the first curved surface (1121a) to an end of the first plane (1121b) connected to the air outlet (114), the first plane (1121b) is inclined toward the outside of the cavity (111).

8. The centrifugal fan according to any one of claims 1 to 7, characterized in that: The housing (11) comprises a side wall (11b), a bottom wall (11a) and a top wall (11c) which are arranged opposite to each other; The side wall (11b) is located between the bottom wall (11a) and the side wall (11b); the side wall (11b), the bottom wall (11a) and the top wall (11c) together enclose the cavity (111); at least one of the bottom wall (11a) and the top wall (11c) is provided with the air inlet (113); the side wall (11b) is provided with the air outlet (114); and the inner surface of the side wall (11b) forms an inner side surface (112) of the cavity (111).

9. The centrifugal fan according to any one of claims 1 to 8, characterized in that: The impeller (12) comprises a wheel disc (122) and a plurality of blades (123), one end of the plurality of blades (123) being fixed on the wheel disc (122), and the other end surfaces of the plurality of blades (123) being flush with the peripheral side surface (121) of the impeller (12).

10. An air cooling system for dissipating heat from a heating device, characterized in that: It comprises a heat dissipation device (20), a heat transfer device (30) and a centrifugal fan (10) according to any one of claims 1 to 9; The heat dissipation device (20) is located at the outlet of the centrifugal fan (10), the heat dissipation device (20) is connected to the heat transfer device (30), and the heat transfer device (30) is used to be connected to the heating element.

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