Impeller, centrifugal fan, and electronic device

Abstract

Embodiments of the present application provide a kind of impeller, centrifugal fan and electronic equipment, relate to fan technical field.The impeller includes hub and the blade of fixed connection on hub.The middle camber line of the airfoil of blade includes first arc segment and second arc segment, first arc segment bends towards the reverse direction of the rotation direction of impeller, second arc segment bends towards the rotation direction of impeller.First arc segment includes leading edge end, and second arc segment includes trailing edge end, leading edge end is located in the one end of first arc segment close to the rotation axis of hub, trailing edge end is located in the one end of second arc segment away from the rotation axis of hub, the one end of first arc segment away from the rotation axis of hub and the one end of second arc segment close to the rotation axis of hub meet. Thus, the air supply of centrifugal fan when running can be larger, and the noise generated is smaller.

Description

TECHNICAL FIELD

[0001] Embodiments of the present application relate to the technical field of fan, in particular to a impeller, centrifugal fan and electronic device. BACKGROUND

[0002] In electronic devices such as mobile phones, tablets, laptops, etc., a centrifugal fan is often provided, which can be used to generate airflow to improve the heat dissipation efficiency of the electronic device. With the continuous improvement of the performance of electronic devices, the heat generated by electronic devices is increasing, and the requirement for the air supply of the centrifugal fan is also increasing.

[0003] The centrifugal fan includes an impeller, and the impeller includes a hub and blades fixedly connected to the hub. Generally, the blades fixedly connected to the hub are straight or C-shaped, and when the air supply of the centrifugal fan is large during operation, a large noise is generated. SUMMARY

[0004] Embodiments of the present application provide an impeller, a centrifugal fan and an electronic device, which can make the air supply of the centrifugal fan large during operation and generate less noise.

[0005] The first aspect of the present application provides an impeller, which includes a hub and blades fixedly connected to the hub. The camber line of the airfoil of the blade includes a first arc segment and a second arc segment, the first arc segment is curved towards the opposite direction of the rotation direction of the impeller, and the second arc segment is curved towards the rotation direction of the impeller. The first arc segment includes a leading edge end, and the second arc segment includes a trailing edge end. The leading edge end is located at one end of the first arc segment close to the rotation axis of the hub, the trailing edge end is located at one end of the second arc segment away from the rotation axis of the hub, and the one end of the first arc segment away from the rotation axis of the hub is connected to the one end of the second arc segment close to the rotation axis of the hub.

[0006] The first arc segment curved in the direction opposite to the rotation direction of the impeller facilitates the blade to form a larger air inlet angle, thereby facilitating the air to enter the airflow channel formed between the adjacent two blades. The second arc segment connected with the first arc segment and curved in the rotation direction of the impeller facilitates the blade to form a larger air outlet angle on the basis of the larger air inlet angle, thereby facilitating the air in the airflow channel formed between the adjacent two blades to flow out. The blade with the larger air inlet angle and the larger air outlet angle facilitates the increase of the air supply amount when the centrifugal fan operates. In addition, through the design of the first arc segment, the air resistance of the blade at the end close to the rotating shaft of the hub is small, and vortex is not easy to be formed, so that the air flows into the airflow channel formed between the adjacent two blades more smoothly, the air flows on the surface of the blade, the noise and the flow loss of the air when the impeller rotates are reduced, and the air supply amount, the noise and the energy efficiency of the centrifugal fan when the centrifugal fan operates are improved. Furthermore, the middle camber line of the airfoil of the blade is formed by the first arc segment and the second arc segment, the airfoil of the blade has a stronger ability to resist the adverse pressure gradient, the air flowing on the surface of the blade when the impeller rotates is not easy to separate from the blade, the air flows more smoothly in the airflow channel formed between the adjacent two blades, the noise and the flow loss of the air when the impeller rotates are reduced, and the air supply amount, the noise and the energy efficiency of the centrifugal fan when the centrifugal fan operates are further improved. Moreover, the middle camber line of the airfoil of the blade is formed by the first arc segment and the second arc segment, the aerodynamic performance of the blade with the larger air inlet angle is better, the working efficiency of the blade with the larger air inlet angle on the air when rotating is improved, the energy efficiency of the blade with the larger air inlet angle when the centrifugal fan operates is improved, the air pressure of the air blown out from the airflow channel formed between the adjacent two blades is increased, and the air supply amount when the centrifugal fan operates is further improved. Compared with the centrifugal fan with straight blades or C-shaped blades, the air supply amount and the air pressure of the centrifugal fan with the middle camber line of the airfoil of the blade including the first arc segment and the second arc segment are larger when the decibels of the generated noise are the same. In addition, since the noise generated between the volute and the impeller of the centrifugal fan when the centrifugal fan operates is small, at this time, the centrifugal fan can meet the requirement of smaller noise under larger air supply amount without adding a sound insulation box outside the volute, the overall size of the centrifugal fan is small, and the centrifugal fan is applied to thinner electronic equipment.

[0007] In a possible implementation, the middle camber line of the airfoil of the blade is a curve with continuous curvature.

[0008] In a possible implementation, the air inlet angle of the blade is greater than or equal to 90° and less than or equal to 125°. The air inlet angle of the blade is the angle between the direction in which the tangent at the leading edge end of the first arc segment points to the outside of the impeller and the direction of the linear velocity of the leading edge end when the impeller rotates.

[0009] In a possible implementation, the air outlet angle of the blade is greater than or equal to 110° and less than or equal to 130°. The air outlet angle of the blade is the angle between the direction of the tangent at the trailing edge end of the second arc segment pointing to the outside of the impeller and the direction of the linear velocity of the trailing edge end when the impeller rotates.

[0010] In a possible implementation, the length of the first arc segment is less than the length of the second arc segment.

[0011] In a possible implementation, the trailing edge end is located in front of the leading edge end in the rotation direction of the impeller.

[0012] In a possible implementation, the impeller includes a plurality of blades arranged at intervals in the circumferential direction of the hub, and an air flow passage is formed between two adjacent blades. An air inlet end of the air flow passage is formed between the end portions of the two adjacent blades close to the rotation axis of the hub. The air flow passage includes a first flow passage segment and a second flow passage segment. The air inlet end is located at one end of the first flow passage segment close to the rotation axis of the hub, and the other end of the first flow passage segment away from the rotation axis of the hub is in communication with one end of the second flow passage segment close to the rotation axis of the hub. The flow passage cross section of the first flow passage segment gradually decreases from the air inlet end to the end of the first flow passage segment in communication with the second flow passage segment. The flow passage cross section of the second flow passage segment gradually increases from the end of the second flow passage segment in communication with the first flow passage segment to the other end of the second flow passage segment away from the rotation axis of the hub.

[0013] In a possible implementation, the ratio of the length of the first flow passage segment in the extension direction of the air flow passage to the length of the second flow passage segment in the extension direction of the air flow passage is greater than or equal to 1 / 3 and less than or equal to 3 / 5.

[0014] In a possible implementation, the air flow passage further includes a third flow passage segment, and an air outlet end of the air flow passage is formed between the end portions of the two adjacent blades away from the rotation axis of the hub. The air outlet end is located at one end of the third flow passage segment away from the rotation axis of the hub, and the other end of the second flow passage segment away from the rotation axis of the hub is in communication with one end of the third flow passage segment close to the rotation axis of the hub. The flow passage cross section of the third flow passage segment remains unchanged from the end of the third flow passage segment in communication with the second flow passage segment to the air outlet end.

[0015] In a possible implementation, the ratio of the length of the third flow passage segment in the extension direction of the air flow passage to the length of the second flow passage segment in the extension direction of the air flow passage is greater than or equal to 1 / 2 and less than or equal to 4 / 5.

[0016] In a possible implementation, the camber line of the airfoil of the blade is a fourth-order Bezier curve, and the leading edge end and the trailing edge end are a starting control point and a terminal control point of the fourth-order Bezier curve respectively. After the coordinates in the impeller polar coordinate system are converted into coordinates in the blade rectangular coordinate system, in the blade rectangular coordinate system: the coordinates of the first intermediate control point of the fourth-order Bezier curve are (x1, y1), the coordinates of the second intermediate control point are (x2, y2), the coordinates of the third intermediate control point are (x3, y3), and the coordinates of the trailing edge end are (x4, y4). Wherein, 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 of the blade rectangular coordinate system is the same as the polar axis direction of 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. -n≤x1≤-0.4n, 0.8n≤y1≤1.4n, 3.4n≤x2≤4n, 3.2n≤y2≤3.8n, 2.2n≤x3≤2.8n, 5.4n≤y3≤6n, 1.2n≤x4≤1.8n, 7.2n≤y4≤7.8n, and n is a positive number.

[0017] The second aspect of the present application provides a centrifugal fan, the centrifugal fan comprising a volute and the impeller in any of the above embodiments, the impeller being mounted in the volute, and the hub of the impeller being rotationally connected with the volute.

[0018] The third aspect of the present application provides an electronic device, the electronic device comprising a housing and the centrifugal fan in any of the above embodiments, the volute of the centrifugal fan being mounted on the housing. BRIEF DESCRIPTION OF DRAWINGS

[0019] Figure 1 A schematic diagram of an electronic device provided by an embodiment of the present application;

[0020] Figure 2 A schematic diagram of another electronic device provided by an embodiment of the present application;

[0021] Figure 3 An exploded view of a centrifugal fan provided by an embodiment of the present application;

[0022] Figure 4 An assembly schematic diagram of an impeller of a centrifugal fan provided by an embodiment of the present application in a volute;

[0023] Figure 5 A schematic diagram of an impeller provided by an embodiment of the present application;

[0024] Figure 6 A schematic diagram of a camber line of an airfoil of a blade in the related art;

[0025] Figure 7A schematic view of a camber line of an airfoil of a blade in a blade rectangular coordinate system is provided for an embodiment of the present application.

[0026] Figure 8 A schematic view of a first airflow passage formed between two adjacent blades of an impeller is provided for an embodiment of the present application.

[0027] BRIEF DESCRIPTION OF DRAWINGS

[0028] 1, housing; 2, heating module; 3, centrifugal fan; 4, first air inlet; 5, first air outlet;

[0029] 10, impeller;

[0030] 20, volute;

[0031] 21, cover plate; 22, side wall; 23, bottom plate;

[0032] 30, drive motor;

[0033] 31, rotor; 32, stator;

[0034] 40, second circuit board;

[0035] 50, second air inlet;

[0036] 60, second air outlet;

[0037] 70, second airflow passage;

[0038] 100, blade;

[0039] 110, 110a, camber line of an airfoil; 111, first arc segment; 1111, leading edge end; 112, second arc segment; 1121, trailing edge end;

[0040] 200, hub;

[0041] 300, first airflow passage;

[0042] 310, first flow passage segment; 311, air inlet end; 320, second flow passage segment; 330, third flow passage segment; 331, air outlet end;

[0043] 400, reinforcing ring;

[0044] T, rotation direction of the impeller; a, a0, air inlet angle; b, b0, air outlet angle;

[0045] X, positive direction of the horizontal axis of the blade rectangular coordinate system; Y, positive direction of the vertical axis of the blade rectangular coordinate system; P1, first intermediate control point; P2, second intermediate control point; P3, third intermediate control point. DETAILED DESCRIPTION

[0046] The terms used in the embodiments of the present application are only used to explain specific embodiments of the present application, and are not intended to limit the present application. The embodiments of the present application will be described in detail below with reference to the accompanying drawings.

[0047] The electronic device provided by the embodiments of the present application can include, but is not limited to, a mobile phone, a tablet computer (PAD), a notebook computer, a personal digital assistant (PDA), a server, a switch, a computing device, a vehicle-mounted device, a wearable device, a virtual reality (VR) terminal device, an augmented reality (AR) terminal device, a wireless terminal in industrial control, a wireless terminal in self driving, a wireless terminal in remote medical, a wireless terminal in smart grid, a wireless terminal in transportation safety, a wireless terminal in smart city, a wireless terminal in smart home, and the like.

[0048] Figure 1 A schematic diagram of an electronic device provided by the embodiments of the present application is shown.

[0049] As shown in Figure 1 In the embodiments of the present application, the electronic device can include a housing 1, a heat generating module 2 and a centrifugal fan 3. The heat generating module 2 can be installed in the housing 1, and the centrifugal fan 3 can be installed on the housing 1. The housing 1 can have a first air inlet 4 and a first air outlet 5. The centrifugal fan 3 can be used to generate air flow to drive air at the heat generating 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 can carry out heat in the housing 1 to improve the heat dissipation efficiency of the electronic device.

[0050] For example, the heat generating module 2 can be a mainboard module, a service board module, a power module, etc. When the electronic device is running, the heat generating module 2 will generate heat. The heat generated by the heat generating module 2 can be transferred to the air in the housing 1.

[0051] Exemplarily, the heat generating module 2 can include a first printed circuit board (PCB) and a chip (not shown), the first PCB is fixedly connected with the shell 1, and the chip is mounted on the first PCB. The chip can include, but is not limited to, a central processing unit (CPU), a graphics processing unit (GPU), etc.

[0052] Exemplarily, the centrifugal fan 3 can be mounted in the shell 1.

[0053] Figure 2 Another schematic diagram of an electronic device provided by an embodiment of the present application.

[0054] As shown in Figure 2 , exemplarily, the centrifugal fan 3 can be mounted outside the shell 1. The centrifugal fan 3 can be used to drive the air outside the shell 1 to flow into the shell 1 through the first air inlet 4, and the air flowing into the shell 1 through the first air inlet 4 can press the original air in the shell 1 out of the first air outlet 5, so that the centrifugal fan 3 mounted outside the shell 1 can drive the air at the heat generating module 2 to flow out of the shell 1 from the first air outlet 5.

[0055] Figure 3 An exploded view of a centrifugal fan provided by an embodiment of the present application, Figure 4 An assembly schematic diagram of an impeller of a centrifugal fan provided by an embodiment of the present application in a volute.

[0056] As shown in Figure 3 , Figure 4 , in the embodiment of the present application, the centrifugal fan 3 can include a volute 20 and an impeller 10, the volute 20 can be used to be mounted on the shell 1, the impeller 10 is mounted in the volute 20, and the impeller 10 is rotatably connected with the volute 20. The volute 20 has a second air inlet 50 and a second air outlet 60, both of which are in communication with the inner cavity of the volute 20, and the rotating impeller 10 can be used to drive the air in the volute 20 to flow, so that the air in the volute 20 is blown out of the second air outlet 60, and the air outside the volute 20 flows into the volute 20 through the second air inlet 50, thereby generating an air flow, and the air blown out of the volute 20 through the second air outlet 60 can be used to drive the air at the heat generating module 2 to flow out of the shell 1 from the first air outlet 5 on the shell 1.

[0057] Exemplarily, the volute 20 can include a cover plate 21, a side wall 22 and a bottom plate 23, the cover plate 21 and the bottom plate 23 are oppositely arranged, the side wall 22 is located between the cover plate 21 and the bottom plate 23, two ends of the side wall 22 are fixedly connected with the cover plate 21 and the bottom plate 23 respectively, the cover plate 21, the bottom plate 23 and the side wall 22 form an inner cavity of the volute 20, the inner cavity of the volute 20 can be used as an inner flow channel of the centrifugal fan 3, and at least one of the cover plate 21 and the bottom plate 23 is provided with the second air inlet 50.

[0058] Exemplarily, the cover plate 21 is provided with the second air inlet 50, and the bottom plate 23 is not provided with the second air inlet 50.

[0059] In this way, the centrifugal fan 3 can take in air from one side, so that the vortex formed in the volute 20 due to inconsistent air inlet directions can be reduced, the noise generated by air vibration in the volute 20 can be reduced, and the noise of the centrifugal fan 3 during operation can be reduced. In addition, the air flows more smoothly in the volute 20, the air has a higher flow speed in the volute 20, and the air supply amount of the centrifugal fan 3 during operation can be improved.

[0060] Exemplarily, the second air inlet 50 is a circular opening with an axis coinciding with the rotation axis of the impeller 10.

[0061] Exemplarily, the second air outlet 60 extends to the bottom plate 23 and the cover plate 21 at two ends respectively, that is, the two ends of the second air outlet 60 connected with the bottom plate 23 and the cover plate 21 are both open structures.

[0062] In this way, the flow cross section of the second air outlet 60 can be larger, and the air supply amount of the centrifugal fan 3 can be improved. In addition, the air backflow formed at the second air outlet 60 towards the volute 20 can be reduced, the vortex formed in the volute 20 can be weakened, the air flows out of the volute 20 more smoothly through the second air outlet 60, the noise generated by air vibration in the volute 20 can be reduced, the air has a higher flow speed in the volute 20, and the noise of the centrifugal fan 3 during operation can be reduced and the air supply amount of the centrifugal fan 3 during operation can be improved.

[0063] In the embodiment, the centrifugal fan 3 can further include a driving motor 30, and the driving motor 30 is used to drive the impeller 10 to rotate.

[0064] Exemplarily, the driving motor 30 can include but is not limited to an electric motor, a hydraulic motor and the like.

[0065] In some examples, the driving motor 30 can include a stator 32 and a rotor 31, the stator 32, the rotor 31 and the impeller 10 are coaxially arranged, the stator 32 is fixedly connected with the volute 20, the rotor 31 is fixedly connected with the impeller 10, the rotor 31 is rotationally connected with the stator 32, the stator 32 is used to drive the rotor 31 to rotate, so as to drive the impeller 10 to rotate relative to the volute 20.

[0066] For example, the centrifugal fan 3 can further include a second circuit board 40, the second circuit board 40 can be fixedly installed on the inner wall of the bottom plate 23, the driving motor 30 can be installed on the second circuit board 40, and the second circuit board 40 can be electrically connected with the driving motor 30 to supply power to the driving motor 30. The second circuit board 40 can adjust the size of the voltage and current supplied to the driving motor 30 to realize speed regulation of the driving motor 30. For example, the stator 32 of the driving motor 30 can be fixedly installed on the second circuit board 40 and electrically connected with the second circuit board 40.

[0067] For example, the stator 32 of the driving motor 30 can drive the rotor 31 to rotate through electromagnetic induction.

[0068] In the embodiment of the present application, the impeller 10 includes a hub 200 and a plurality of blades 100 arranged at intervals along the circumference of the hub 200, the blade 100 is fixedly connected with the hub 200, the hub 200 is rotationally connected with the volute 20, and the impeller 10 rotates around the rotation axis of the hub 200.

[0069] For example, the blade 100 can be fixedly connected with the hub 200 by welding, clamping, fastening, integral molding or the like.

[0070] For example, the hub 200 can be rotationally connected with the volute 20 through the driving motor 30.

[0071] In the example that the driving motor 30 includes the stator 32 and the rotor 31, the stator 32, the rotor 31 and the hub 200 are coaxially arranged, and the rotor 31 is fixedly connected with the hub 200.

[0072] For example, the blade 100 can be connected with the outer wall of the hub 200 at the end close to the rotation axis of the hub 200.

[0073] In this way, the influence of the hub 200 on the flow of air between two adjacent blades 100 is small.

[0074] For example, the blades 100 of the impeller 10 can be distributed at equal intervals along the circumference of the hub 200.

[0075] In this embodiment, a first airflow channel 300 is formed between two adjacent blades 100 and the cover plate 21 and the bottom plate 23. An air inlet 311 of the first airflow channel 300 is formed between the ends of two adjacent blades 100 near the rotation axis of the hub 200, and an air outlet 331 of the first airflow channel 300 is formed between the ends of two adjacent blades 100 away from the rotation axis of the hub 200. The air inlet 311 is connected to the second air inlet 50. The rotational outer contour formed by the rotational path of the end of the blade 100 away from the rotational axis of the hub 200 forms a second airflow channel 70 between the side wall 22, the cover plate 21, and the bottom plate 23. The air outlet 331 is connected to the second air outlet 60 through the second airflow channel 70. When the impeller 10 rotates, the air outside the volute 20 enters the first airflow channel 300 through the second air inlet 50. The impeller 10 drives the air in the first airflow channel 300 to perform centrifugal motion, so that the air in the first airflow channel 300 enters the second airflow channel 70 through the air outlet 331. The second airflow channel 70 guides the air entering it to the second air outlet 60, so that the air in the volute 20 is blown out through the second air outlet 60.

[0076] In some examples where the second air inlet 50 is a circular opening whose axis coincides with the rotation axis of the impeller 10, the radius of the second air inlet 50 can be greater than the radius of the inner contour of the rotation path formed by the rotation path of the end of the blade 100 near the rotation axis of the hub 200. That is, the radius of the second air inlet 50 can be greater than the distance between the end of the blade 100 near the rotation axis of the hub 200 and the rotation axis of the hub 200.

[0077] The distance between the rotational outer contour formed by the rotational path of the end of the blade 100 away from the rotational axis of the hub 200 and the sidewall 22 can gradually increase from the volute tongue (not shown) of the sidewall 22 to the second air outlet 60, so that the flow cross-section of the second airflow channel 70 gradually increases from the volute tongue of the sidewall 22 to the second air outlet 60. The volute tongue of the sidewall 22 can be arranged adjacent to the second air outlet 60.

[0078] Figure 5 This is a schematic diagram of an impeller provided in an embodiment of this application. The T direction represents the rotation direction of the impeller 10.

[0079] like Figure 5 As shown, the airfoil 110 of the blade 100 includes a leading edge 1111 and a trailing edge 1121. The leading edge 1111 is located at the end of the airfoil 110 of the blade 100 that is close to the rotation axis of the hub 200, and the trailing edge 1121 is located at the end of the airfoil 110 of the blade 100 that is away from the rotation axis of the hub 200.

[0080] It should be noted that the section where the airfoil of the blade 100 is located is perpendicular to the extension direction of the blade 100 extending from the end close to the bottom plate 23 to the end close to the cover plate 21. For example, when the blade 100 extends along the axial direction of the rotation shaft of the impeller 10 from the end close to the bottom plate 23 to the end close to the cover plate 21, the section where the airfoil of the blade 100 is located can be perpendicular to the rotation shaft of the impeller 10.

[0081] The camber line 110 of the airfoil of the blade 100 is a continuous line segment formed by the center of the inscribed circle of the profile of the airfoil of the blade 100, that is, the distance from a point on the camber line 110 of the airfoil of the blade 100 to the profile of the airfoil of the blade 100 on both sides thereof is equal. After the camber line 110 of the airfoil of the blade 100 is determined, the profile of the airfoil of the blade 100 can be determined according to the distribution rule of the thickness of the blade 100, and then the shape of the blade 100 can be determined.

[0082] In some examples, the blade 100 can be a plate-shaped structure with equal thickness.

[0083] In the embodiment of the present application, the blade 100 of the impeller 10 has an inlet angle a and an outlet angle β, the inlet angle a of the blade 100 is the included angle between the direction of the tangent to the camber line 110 of the airfoil of the blade 100 at the leading edge end 1111 pointing to the outside of the impeller 10 and the direction of the linear velocity of the leading edge end 1111 when the impeller 10 rotates, and the outlet angle β of the blade 100 is the included angle between the direction of the tangent to the camber line 110 of the airfoil of the blade 100 at the trailing edge end 1121 pointing to the outside of the impeller 10 and the direction of the linear velocity of the leading edge end 1111 when the impeller 10 rotates.

[0084] In order to make the centrifugal fan 3 have a larger air supply amount, it is necessary to make the inlet angle a of the blade 100 have a larger angle.

[0085] In the related art, the blade of the centrifugal fan is often a straight blade or a C-shaped blade, that is, the camber line of the airfoil of the blade is a straight line segment or a C-shaped line segment. Figure 6 A schematic view of the camber line of the airfoil of a blade in the related art. As shown in FIG. 6, the camber line of the airfoil of the blade is a C-shaped line segment. Figure 6As shown, for example, the camber line 110a of the airfoil of the blade can include two arc segments curved toward the rotation direction of the impeller and a straight segment connecting the two arc segments, the straight segment being tangent to the two arc segments, and the two arc segments being connected to the straight segment so that the camber line 110a of the airfoil of the blade is a C-shaped segment. In the related art, when the angle of the inlet angle a0 of the blade is large, the air in the first airflow channel separates from the surface of the blade more seriously when flowing, the aerodynamic performance of the blade is poor, which makes the noise of the impeller when rotating larger, the air working efficiency of the blade is lower, and the noise of the centrifugal fan when running is larger and the energy efficiency is lower. In order to make the noise generated by the centrifugal fan when running not too large, the inlet angle a0 of the blade of the centrifugal fan in the related art is usually less than 80°, but at this time, the inlet flow of the first airflow channel is small, which will cause the air supply of the centrifugal fan to be small.

[0086] In some related art, there is a scheme of adding a sound insulation box outside the volute of the centrifugal fan to reduce the noise transmitted to the user and the external environment. However, after adding the sound insulation box, the overall size of the centrifugal fan is large, which is not conducive to the application of the centrifugal fan to the relatively thin electronic equipment.

[0087] Based on this, as Figure 5 shown, and referring to Figure 3 , Figure 4 In the embodiment of the present application, the camber line 110 of the airfoil of the blade 100 includes a first arc segment 111 and a second arc segment 112. The first arc segment 111 is curved toward the opposite direction of the rotation direction of the impeller 10, that is, along the rotation direction of the impeller 10, the two ends of the first arc segment 111 are located in front of the camber of the first arc segment 111. The second arc segment 112 is curved toward the rotation direction of the impeller 10, that is, along the rotation direction of the impeller 10, the two ends of the second arc segment 112 are located behind the camber of the second arc segment 112. The first arc segment 111 includes a leading edge end 1111, and the second arc segment 112 includes a trailing edge end 1121. The leading edge end 1111 is located at one end of the first arc segment 111 close to the rotation axis of the hub 200, the trailing edge end 1121 is located at one end of the second arc segment 112 away from the rotation axis of the hub 200, and one end of the first arc segment 111 away from the rotation axis of the hub 200 is connected to one end of the second arc segment 112 close to the rotation axis of the hub 200.

[0088] Thus, the first arc segment 111 curved in the opposite direction of the rotation direction of the impeller 10 is conducive to the blade 100 forming a larger air inlet angle a, and the second arc segment 112 curved in the rotation direction of the impeller 10 and connected with the first arc segment 111 is conducive to the blade 100 forming a larger air outlet angle β on the basis of the blade 100 having a larger air inlet angle a, and thus conducive to the air in the first airflow passage 300 flowing out. The blade 100 having a larger air inlet angle a and a larger air outlet angle β is conducive to increasing the air supply amount when the centrifugal fan 3 operates. In addition, through the design of the first arc segment 111, the air resistance of the blade 100 at the end close to the rotation axis of the hub 200 is small and vortex is not easy to form, the air can flow into the first airflow passage 300 more smoothly, the air flowing on the surface of the blade 100 is conducive to reducing, the noise and flow loss of the air when the impeller 10 rotates, and the air supply amount, noise reduction and energy efficiency improvement of the centrifugal fan 3 when operating are conducive to. In addition, the middle camber line 110 of the airfoil of the blade 100 is formed by the first arc segment 111 and the second arc segment 112, the airfoil of the blade 100 has a stronger ability to resist adverse pressure gradient, so that the air flowing on the surface of the blade 100 is not easy to separate from the blade 100 when the impeller 10 rotates, the air flows more smoothly in the first airflow passage 300, which is conducive to reducing the noise and flow loss of the air when the impeller 10 rotates, and further conducive to increasing the air supply amount, reducing the noise and improving the energy efficiency of the centrifugal fan 3 when operating. Furthermore, the middle camber line 110 of the airfoil of the blade 100 is formed by the first arc segment 111 and the second arc segment 112, which can make the blade 100 with a larger air inlet angle a have better aerodynamic performance, improve the work efficiency of the blade 100 with a larger air inlet angle a on the air when rotating, improve the energy efficiency of the centrifugal fan 3 when operating and increase the air pressure of the air flowing out of the air outlet end 331, and further improve the air supply amount when the centrifugal fan 3 operates. Compared with the centrifugal fan with straight or C-shaped blades, the air supply amount and the air supply pressure of the centrifugal fan 3 with the middle camber line 110 of the airfoil of the blade 100 including the first arc segment 111 and the second arc segment 112 are larger at the same decibel of the generated noise. In addition, since the noise generated between the volute 20 and the impeller 10 when the centrifugal fan 3 operates is small, at this time, it is not necessary to additionally install a sound insulation box outside the volute 20 to meet the requirement of smaller noise under larger air supply amount, and the overall size of the centrifugal fan 3 is smaller, which is conducive to applying the centrifugal fan 3 to thinner electronic devices.

[0089] It should be noted that in the present application, unless otherwise specified, the description of the relative relationship of the structures on the blade 100, such as the first arc segment 111, the second arc segment 112, the leading edge end 1111, the trailing edge end 1121, etc., refers to the relative relationship of the structures on the same blade 100.

[0090] In some examples, the impeller 10 can further include a reinforcing ring 400, the reinforcing ring 400 is coaxially arranged with the rotation axis of the hub 200, and the end of all the blades 100 of the impeller 10 away from the rotation axis of the hub 200 can be fixedly connected through the reinforcing ring 400, and the reinforcing ring 400 is fixedly connected to the side of the blade 100 facing the cover plate 21 or the side of the blade 100 facing the bottom plate 23.

[0091] In this way, the strength of the blade 100 is improved, so that the blade 100 is less likely to deform when the impeller 10 rotates, and the designed noise, air intake and aerodynamic performance are facilitated to be maintained. In addition, the reinforcing ring 400 is fixedly connected to the side of the blade 100 facing the cover plate 21 or the side of the blade 100 facing the bottom plate 23, so that the reinforcing ring 400 has less influence on the air in the first airflow passage 300 flowing into the second airflow passage 70 through the air outlet end 331.

[0092] For example, the reinforcing ring 400 can be fixedly connected with the blade 100 by welding, clamping, one-piece forming or the like.

[0093] In some examples, the camber line 110 of the airfoil of the blade 100 can be a tangent-continuous curve.

[0094] In this way, the blade 100 is easier to process and has lower manufacturing cost.

[0095] In some examples, the camber line 110 of the airfoil of the blade 100 can be a curvature-continuous curve.

[0096] In this way, when the impeller 10 rotates, the air in the first airflow passage 300 is facilitated to flow along the surface of the blade 100, and the air in the first airflow passage 300 is less likely to separate from the surface of the blade 100 when flowing, so as to reduce the noise and air flow loss when the impeller 10 rotates. In addition, the blade 100 is easier to process and has lower manufacturing cost.

[0097] In some examples, the camber line 110 of the airfoil of the blade 100 can be a curvature-continuous curve.

[0098] In this way, when the impeller 10 rotates, the air in the first airflow passage 300 is facilitated to flow along the surface of the blade 100, and the air in the first airflow passage 300 is less likely to separate from the surface of the blade 100 when flowing, so as to reduce the noise and air flow loss when the impeller 10 rotates. In addition, the blade 100 is easier to process and has lower manufacturing cost.

[0099] In some possible embodiments, the air inlet angle a of the blade 100 is greater than or equal to 90° and less than or equal to 125°. At this time, the air inlet angle a of the blade 100 is an angle between a direction of a tangent of the first arc segment 111 at the leading edge end 1111 pointing to the outside of the impeller 10 and a direction of a linear velocity of the leading edge end 1111 when the impeller 10 rotates.

[0100] In this way, the air inlet angle a of the blade 100 is relatively large, which is conducive to the air entering the first airflow passage 300, and the first airflow passage 300 has a relatively smooth air inlet, which is conducive to the first airflow passage 300 having a relatively large air inlet amount and improving the air supply amount of the centrifugal fan 3. In addition, the vortex is not easy to form at the air inlet end 311, which is conducive to reducing the noise generated by the rotation of the impeller 10 and the flow loss of the air. In addition, the bending degree of the first arc segment 111 can be relatively small, and the air is not easy to separate from the surface of the blade 100 when the air is guided to the part corresponding to the second arc segment 112 from the part corresponding to the first arc segment 111 on the surface of the blade 100, which is conducive to reducing the noise generated by the rotation of the impeller 10 and the flow loss of the air. Furthermore, the length of the first arc segment 111 can be relatively short, and the length of the second arc segment 112 can be relatively long. The relatively long length of the second arc segment 112 can make the blade 100 have a relatively high work efficiency on the air when the blade 100 rotates, which is conducive to improving the energy efficiency of the centrifugal fan 3 during operation and increasing the air pressure of the air flowing out of the air outlet end 331, and is conducive to further improving the air supply amount of the centrifugal fan 3 during operation. In addition, the relatively short length of the first arc segment 111 and the relatively long length of the second arc segment 112 are conducive to the air in the first airflow passage 300 adhering to the surface of the blade 100 after reducing the air resistance of the air inlet of the first airflow passage 300, which is conducive to reducing the noise generated by the rotation of the impeller 10 and the flow loss of the air.

[0101] For example, the air inlet angle a of the blade 100 can include but is not limited to 90°, 95°, 98°, 100°, 104°, 107°, 110°, 112°, 115°, 118°, 120°, 121°, 125°, etc.

[0102] In some possible embodiments, the air outlet angle b of the blade 100 is greater than or equal to 110° and less than or equal to 130°. At this time, the air outlet angle b of the blade 100 is an angle between a direction of a tangent of the second arc segment 112 at the trailing edge end 1121 pointing to the outside of the impeller 10 and a direction of a linear velocity of the trailing edge end 1121 when the impeller 10 rotates.

[0103] In this way, the outlet angle β of the blade 100 is relatively large, which allows air to flow out more smoothly from the first airflow channel 300, thus improving the air volume delivered by the centrifugal fan 3. In addition, the blade 100 has a high work efficiency when rotating, which helps to improve the energy efficiency of the centrifugal fan 3 during operation and increases the air pressure of the air flowing out from the outlet end 331, which further helps to improve the air volume delivered by the centrifugal fan 3 during operation.

[0104] For example, the outlet angle β of the blade 100 may include, but is not limited to, 110°, 112°, 114°, 115°, 118°, 120°, 123°, 126°, 128°, 130°, etc.

[0105] In some possible implementations, the length of the first arc segment 111 is less than the length of the second arc segment 112.

[0106] Thus, the longer length of the second arc segment 112 allows for higher work efficiency of the blades 100 when rotating, which is beneficial for improving the energy efficiency of the centrifugal fan 3 and increasing the air pressure flowing out from the outlet 331, thereby further increasing the air volume delivered by the centrifugal fan 3. In addition, the shorter length of the first arc segment 111 and the longer length of the second arc segment 112 are beneficial for reducing the air resistance at the intake of the first airflow channel 300, allowing the air in the first airflow channel 300 to adhere to the surface of the blades 100 and flow, which helps to reduce the noise generated by the rotation of the impeller 10 and the airflow loss.

[0107] In some possible implementations, the trailing edge 1121 is located in front of the leading edge 1111 along the direction of rotation of the impeller 10.

[0108] This allows the blades 100, which have a larger inlet angle α, to have a larger outlet angle β, making the air flow out of the first airflow channel 300 more smoothly and the blades 100 more efficient at doing work on the air when they rotate.

[0109] Figure 7 This is a schematic diagram of the mid-arc line of a blade airfoil provided in an embodiment of this application, in a blade rectangular coordinate system. The X direction is the positive direction of the horizontal axis of the blade rectangular coordinate system, the Y direction is the positive direction of the vertical axis of the blade rectangular coordinate system, P1 is the first intermediate control point, P2 is the second intermediate control point, and P3 is the third intermediate control point.

[0110] like Figure 7 As shown, in some possible embodiments, the mid-arc 110 of the airfoil of the blade 100 is a fourth-order Bézier curve, and the leading edge 1111 and trailing edge 1121 are the starting control point and ending control point of the fourth-order Bézier curve, respectively.

[0111] Thus, the design and manufacture of the airfoil of the blade 100 are easier. In addition, the aerodynamic performance of the formed blade 100 is better, and the air in the first air flow passage 300 is beneficial to adhere to the surface of the formed blade 100 when the impeller 10 rotates, the air in the first air flow passage 300 is not easy to separate from the surface of the blade 100 when flowing, and it is beneficial to reduce the noise and air flow loss when the impeller 10 rotates.

[0112] In some examples in which the camber line 110 of the airfoil of the blade 100 is a fourth-order Bezier curve, after the coordinates in the impeller polar coordinate system are converted into the coordinates in the blade rectangular coordinate system, in the blade rectangular coordinate system: the coordinates of the first intermediate control point P1 of the fourth-order Bezier curve are (x1, y1), the coordinates of the second intermediate control point P2 are (x2, y2), the coordinates of the third intermediate control point P3 are (x3, y3), and the coordinates of the trailing edge end 1121 are (x4, y4). Wherein, the pole point in the impeller polar coordinate system is located on the rotation axis of the hub 200, the polar angle of the leading edge end 1111 in the impeller polar coordinate system is π / 2, the origin of the blade rectangular coordinate system is located at the leading edge end 1111, the horizontal axis direction of the blade rectangular coordinate system is the same as the polar axis direction of the impeller polar coordinate system, and the positive direction of the vertical axis of the blade rectangular coordinate system is the direction of the leading edge end 1111 pointing to the outside of the impeller 10 along the radial direction of the impeller 10. -n≤x1≤-0.4n, 0.8n≤y1≤1.4n, 3.4n≤x2≤4n, 3.2n≤y2≤3.8n, 2.2n≤x3≤2.8n, 5.4n≤y3≤6n, 1.2n≤x4≤1.8n, 7.2n≤y4≤7.8n, n is a positive number.

[0113] Therefore, the air inlet angle a and the air outlet angle b of the blade 100 are large, which is beneficial to the air entering the first airflow passage 300 and the air flowing out of the first airflow passage 300, and the air supply amount of the centrifugal fan 3 during operation can be large. In addition, the air resistance of the blade 100 at the end close to the rotating shaft of the hub 200 is small, and vortex is not easy to form, which makes the air flow into the first airflow passage 300 more smoothly, and is beneficial to the air adhering to the surface of the blade 100 to flow, which can reduce the noise and flow loss of the air during rotation of the impeller 10, and is beneficial to increase the air supply amount, reduce the noise, and improve the energy efficiency during operation of the centrifugal fan 3. In addition, the fitting degree of the airfoil shape of the blade 100 to the flow field of the air in the first airflow passage 300 is high, and the airfoil shape of the blade 100 has strong resistance to the adverse pressure gradient, so that the air adhering to the surface of the blade 100 during rotation of the impeller 10 is not easy to separate from the blade 100, and the air flows more smoothly in the first airflow passage 300, which is beneficial to reduce the noise and flow loss of the air during rotation of the impeller 10, and is beneficial to increase the air supply amount, reduce the noise, and improve the energy efficiency during operation of the centrifugal fan 3. Furthermore, since the fitting degree of the airfoil shape of the blade 100 to the flow field of the air in the first airflow passage 300 is high, the aerodynamic performance of the blade 100 is good, the working efficiency of the blade 100 on the air during rotation is high, the energy efficiency during operation of the centrifugal fan 3 is high, the air pressure of the air flowing out of the air outlet end 331 is large, and the air supply amount during operation of the centrifugal fan 3 is high. In addition, the size of the blade 100 can be adjusted by adjusting the size of n, so that centrifugal fans 3 of different sizes with large air supply amount and small noise can be manufactured.

[0114] In the process of converting the coordinates in the impeller polar coordinate system into the coordinates in the blade rectangular coordinate system, the coordinates in the impeller polar coordinate system can be first converted into the coordinates in the impeller rectangular coordinate system through the conversion method of the polar coordinate system and the rectangular coordinate system, and then the coordinates in the impeller rectangular coordinate system can be converted into the coordinates in the blade rectangular coordinate system through translation or other methods. The origin of the impeller rectangular coordinate system is located on the rotating shaft of the hub 200, the horizontal axis in the impeller rectangular coordinate system coincides with the polar axis in the impeller polar coordinate system, the positive direction of the vertical axis of the impeller rectangular coordinate system is the direction in which the rotating shaft of the hub 200 points to the outside of the impeller 10 along the radial direction of the impeller 10, and the unit of the horizontal coordinate in the blade rectangular coordinate system is the same as the unit of the vertical coordinate, for example, the unit of the horizontal coordinate and the unit of the vertical coordinate in the blade rectangular coordinate system can both be meters, decimeters, centimeters, etc.

[0115] For example, n can include but is not limited to 0.1, 0.01, 0.2, 0.5, 1, 1.5, 2, 3, 5, 8, 10, 100, etc.

[0116] Exemplarily, the unit of the horizontal coordinate and the unit of the vertical coordinate in the blade rectangular coordinate system are both decimeters, the coordinates of the first intermediate control point P1 of the fourth-order Bezier curve in the blade rectangular coordinate system can be (-0.06, 0.1), the coordinates of the second intermediate control point P2 can be (0.36, 0.34), the coordinates of the third intermediate control point P3 can be (0.24, 0.56), the coordinates of the trailing edge end 1121 can be (0.14, 0.74), and the coordinates of the leading edge end 1111 can be (0, 0).

[0117] Figure 8 A schematic view of a first air flow channel formed between two adjacent blades of an impeller is provided in an embodiment of the present application.

[0118] As shown in Figure 8 some possible embodiments, the first air flow channel 300 includes a first flow passage section 310 and a second flow passage section 320. An air inlet end 311 is located at one end of the first flow passage section 310 close to the rotation axis of the hub 200, and one end of the first flow passage section 310 away from the rotation axis of the hub 200 is in communication with one end of the second flow passage section 320 close to the rotation axis of the hub 200. The flow passage cross section of the first flow passage section 310 gradually decreases from the air inlet end 311 to the end in communication with the second flow passage section 320. The flow passage cross section of the second flow passage section 320 gradually increases from the end in communication with the first flow passage section 310 to the end of the second flow passage section 320 away from the rotation axis of the hub 200.

[0119] In this way, when the air flows in the first flow passage section 310, the flow velocity gradually decreases and the pressure slowly increases, which can not only make the air flow smoothly in the first air flow channel 300, but also inhibit the impact of high turbulence degree air flow, thereby reducing the noise and flow loss of the air when the impeller 10 rotates. When the air flows in the second flow passage section 320, the flow velocity gradually increases, which is beneficial to improve the air supply amount when the centrifugal fan 3 operates, and can make the centrifugal fan 3 operate with smaller noise and larger air supply amount.

[0120] In some possible embodiments, the ratio of the length of the first flow passage section 310 along the extension direction of the first air flow channel 300 to the length of the second flow passage section 320 along the extension direction of the first air flow channel 300 is greater than or equal to 1 / 3 and less than or equal to 3 / 5.

[0121] In this way, a better balance between the noise generated when the air flows through the first flow passage section 310 and the second flow passage section 320 and the aerodynamic performance of the first flow passage section 310 and the second flow passage section 320 can be achieved, which can make the centrifugal fan 3 operate with smaller noise and larger air supply amount.

[0122] For example, the ratio of the length of the first flow passage section 310 along the extension direction of the first airflow passage 300 to the length of the second flow passage section 320 along the extension direction of the first airflow passage 300 can include, but is not limited to, 1 / 3, 2 / 5, 1 / 2, 3 / 5, etc.

[0123] In some possible embodiments, the first airflow passage 300 further includes a third flow passage section 330. An air outlet end 331 is located at one end of the third flow passage section 330 away from the rotation axis of the hub 200, and one end of the second flow passage section 320 away from the rotation axis of the hub 200 is in communication with one end of the third flow passage section 330 close to the rotation axis of the hub 200. From the end of the third flow passage section 330 in communication with the second flow passage section 320 to the air outlet end 331, the cross-sectional area of the third flow passage section 330 remains unchanged.

[0124] In this way, the influence of the air pressure change of the air outlet end 331 on the air flow in the first airflow passage 300 when the impeller 10 rotates can be reduced, the air flows more smoothly and stably in the first airflow passage 300, and the noise generated by the air flowing through the first airflow passage 300 can be reduced.

[0125] It can be understood that the cross-sectional area of the third flow passage section 330 remaining unchanged in the present application does not mean that the cross-sectional area of the third flow passage section 330 remains absolutely unchanged. Due to production process and other reasons, the cross-sectional area of the third flow passage section 330 at different positions from the end of the third flow passage section 330 in communication with the second flow passage section 320 to the air outlet end 331 can have a certain error.

[0126] In some possible embodiments, the ratio of the length of the third flow passage section 330 along the extension direction of the first airflow passage 300 to the length of the second flow passage section 320 along the extension direction of the first airflow passage 300 is greater than or equal to 1 / 2 and less than or equal to 4 / 5.

[0127] In this way, a better balance between the noise generated by the air flowing through the first airflow passage 300 and the aerodynamic performance of the first airflow passage 300 can be achieved, so that the centrifugal fan 3 can operate with smaller noise and larger air supply.

[0128] For example, the ratio of the length of the third flow passage section 330 along the extension direction of the first airflow passage 300 to the length of the second flow passage section 320 along the extension direction of the first airflow passage 300 can include, but is not limited to, 1 / 2, 3 / 5, 2 / 3, 4 / 5, etc.

[0129] In some examples in which the first air flow passage 300 includes the first flow passage section 310, the second flow passage section 320, and the third flow passage section 330, the ratio of the length of the first flow passage section 310 to the length of the first air flow passage 300 can be greater than or equal to 1 / 5 and less than or equal to 1 / 4, for example, the ratio of the length of the first flow passage section 310 to the length of the first air flow passage 300 can be 1 / 5. The ratio of the sum of the length of the first flow passage section 310 and the length of the second flow passage section 320 to the length of the first air flow passage 300 can be greater than or equal to 7 / 12 and less than or equal to 9 / 12, for example, the ratio of the sum of the length of the first flow passage section 310 and the length of the second flow passage section 320 to the length of the first air flow passage 300 can be 2 / 3.

[0130] In this way, a better balance between the noise generated when air flows through the first air flow passage 300 and the aerodynamic performance of the first air flow passage 300 can be achieved, so that the centrifugal fan 3 can operate with less noise and a larger air supply.

[0131] It should be noted that, in the present application, unless otherwise specified, the description of the relative relationship of the parts of the first air flow passage 300, such as the first flow passage section 310, the second flow passage section 320, the third flow passage section 330, the air inlet end 311, and the air outlet end 331, refers to the relative relationship of the parts of the same first air flow passage 300.

[0132] In the description of the embodiments of the present application, it should be noted that, unless otherwise specified and limited, the terms "mounting", "connecting", and "connection" should be interpreted in a broad sense, for example, can be fixed connection, can be indirect connection through an intermediate medium, or can be the communication inside two elements or the interaction relationship between two elements. For those skilled in the art, the specific meaning of the above terms in the embodiments of the present application can be understood according to the specific circumstances.

[0133] In the embodiments of the present application or the devices or elements implied by the embodiments of the present application must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation of the embodiments of the present application. In the description of the embodiments of the present application, the meaning of "multiple" is two or more, unless otherwise specified and limited.

[0134] The terms "first", "second", "third", "fourth" etc. (if any) in the description and claims of the present application and above drawings are used to distinguish similar objects, and do not have to be used to describe a specific order or sequence. It should be understood that the data thus used can be interchanged under appropriate circumstances, so that the embodiments of the present application described herein can be implemented, for example, in an order other than that illustrated or described herein. In addition, the terms "include" and "have" and any variations thereof are intended to cover non-exclusive inclusion, for example, a process, method, system, product or device that includes a series of steps or units does not have to be limited to those steps or units clearly listed, but can include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0135] The term "a plurality of" herein refers to two or more. The term "and / or" herein is merely a description of the association relationship between the associated objects, which means that there can be three relationships, for example, A and / or B can represent the three cases of A existing alone, A and B existing together, and B existing alone. In addition, the character " / " herein generally represents that the associated objects before and after it are in an "or" relationship; in formulas, the character " / " represents that the associated objects before and after it are in a "division" relationship.

[0136] It can be understood that the various numerical numbers involved in the embodiments of the present application are only distinguished for convenience of description, and do not limit the scope of the embodiments of the present application.

[0137] It can be understood that in the embodiments of the present application, the size of the serial number of the above processes does not mean the order of execution, and the execution order of the processes should be determined according to their functions and inherent logic, and should not constitute any limitation on the implementation process of the embodiments of the present application.

Claims

1. An impeller, characterized in that, Includes a hub and blades fixedly connected to the hub; The airfoil of the blade includes a first arc segment and a second arc segment. The first arc segment bends in the opposite direction to the rotation direction of the impeller, and the second arc segment bends in the rotation direction of the impeller. The first arc segment includes a leading edge end, and the second arc segment includes a trailing edge end. The leading edge end is located at one end of the first arc segment near the rotation axis of the hub, and the trailing edge end is located at one end of the second arc segment away from the rotation axis of the hub. The end of the first arc segment away from the rotation axis of the hub is connected to the end of the second arc segment near the rotation axis of the hub. The impeller includes a plurality of blades spaced circumferentially along the hub, and an airflow channel is formed between two adjacent blades. The airflow channel includes a first flow channel section, a second flow channel section, and a third flow channel section. The end of the first flow channel section away from the rotation axis of the hub is connected to the end of the second flow channel section close to the rotation axis of the hub, and the end of the second flow channel section away from the rotation axis of the hub is connected to the end of the third flow channel section close to the rotation axis of the hub. From the air inlet to the end where the first flow channel section connects with the second flow channel section, the flow cross-section of the first flow channel section gradually decreases; from the end where the second flow channel section connects with the first flow channel section to the end of the second flow channel section away from the rotation axis of the hub, the flow cross-section of the second flow channel section gradually increases; from the end where the third flow channel section connects with the second flow channel section to the air outlet, the flow cross-section of the third flow channel section remains unchanged. The ratio of the length of the first flow channel segment along the extension direction of the airflow channel to the length of the second flow channel segment along the extension direction of the airflow channel is greater than or equal to 1 / 3 and less than or equal to 3 / 5. The ratio of the length of the third flow channel segment along the extension direction of the airflow channel to the length of the second flow channel segment along the extension direction of the airflow channel is greater than or equal to 1 / 2 and less than or equal to 4 / 5. The airfoil of the blade has a mid-curve that is a fourth-order Bézier curve, and the leading edge and trailing edge are the starting and ending control points of the fourth-order Bézier curve, respectively. After converting the coordinates in the impeller polar coordinate system to the blade rectangular coordinate system, in the blade rectangular coordinate system: the coordinates of the first intermediate control point of the fourth-order Bézier curve are (x1, y1), the coordinates of the second intermediate control point are (x2, y2), the coordinates of the third intermediate control point are (x3, y3), and the coordinates of the trailing edge are (x4, y4). Wherein, the pole of 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 of the blade rectangular coordinate system is the same as the polar axis direction 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 end along the radial direction of the impeller to the outside of the impeller. -n≤x1≤-0.4n, 0.8n≤y1≤1.4n, 3.4n≤x2≤4n, 3.2n≤y2≤3.8n, 2.2n≤x3≤2.8n, 5.4n≤y3≤6n, 1.2n≤x4≤1.8n, 7.2n≤y4≤7.8n, where n is a positive number.

2. The impeller according to claim 1, characterized in that, The airfoil of the blade has a mid-curve that is a curve with continuous curvature.

3. The impeller according to claim 1 or 2, characterized in that, The air inlet angle of the blade is greater than or equal to 90° and less than or equal to 125°; Wherein, the air inlet angle of the blade is the angle between the direction of the tangent at the leading edge end along the first arc segment pointing outward from the impeller and the direction of the linear velocity at the leading edge end when the impeller rotates.

4. The impeller according to claim 1 or 2, characterized in that, The air outlet angle of the blade is greater than or equal to 110° and less than or equal to 130°; Wherein, the air outlet angle of the blade is the angle between the direction of the tangent at the trailing edge of the second arc segment pointing outward from the impeller and the direction of the linear velocity at the trailing edge when the impeller rotates.

5. The impeller according to claim 3, characterized in that, The air outlet angle of the blade is greater than or equal to 110° and less than or equal to 130°; Wherein, the air outlet angle of the blade is the angle between the direction of the tangent at the trailing edge of the second arc segment pointing outward from the impeller and the direction of the linear velocity at the trailing edge when the impeller rotates.

6. The impeller according to any one of claims 1, 2, and 5, characterized in that, The length of the first arc segment is less than the length of the second arc segment.

7. The impeller according to claim 3, characterized in that, The length of the first arc segment is less than the length of the second arc segment.

8. The impeller according to claim 4, characterized in that, The length of the first arc segment is less than the length of the second arc segment.

9. The impeller according to any one of claims 1, 2, 5, 7, and 8, characterized in that, Along the direction of rotation of the impeller, the trailing edge is located in front of the leading edge.

10. The impeller according to claim 3, characterized in that, Along the direction of rotation of the impeller, the trailing edge is located in front of the leading edge.

11. The impeller according to claim 4, characterized in that, Along the direction of rotation of the impeller, the trailing edge is located in front of the leading edge.

12. The impeller according to claim 6, characterized in that, Along the direction of rotation of the impeller, the trailing edge is located in front of the leading edge.

13. The impeller according to any one of claims 1, 2, 5, 7, 8, 10-12, characterized in that, The air inlet of the airflow channel is formed between the ends of two adjacent blades near the rotation axis of the hub; The air inlet is located at one end of the first flow channel section near the rotating shaft of the hub.

14. The impeller according to claim 3, characterized in that, The air inlet of the airflow channel is formed between the ends of two adjacent blades near the rotation axis of the hub; The air inlet is located at one end of the first flow channel section near the rotating shaft of the hub.

15. The impeller according to claim 4, characterized in that, The air inlet of the airflow channel is formed between the ends of two adjacent blades near the rotation axis of the hub; The air inlet is located at one end of the first flow channel section near the rotating shaft of the hub.

16. The impeller according to claim 6, characterized in that, The air inlet of the airflow channel is formed between the ends of two adjacent blades near the rotation axis of the hub; The air inlet is located at one end of the first flow channel section near the rotating shaft of the hub.

17. The impeller according to claim 9, characterized in that, The air inlet of the airflow channel is formed between the ends of two adjacent blades near the rotation axis of the hub; The air inlet is located at one end of the first flow channel section near the rotating shaft of the hub.

18. The impeller according to claim 13, characterized in that, The air outlet of the airflow channel is formed between the ends of two adjacent blades that are away from the rotation axis of the hub. The air outlet is located at the end of the third flow channel section away from the rotation axis of the hub.

19. The impeller according to any one of claims 14-17, characterized in that, The air outlet of the airflow channel is formed between the ends of two adjacent blades that are away from the rotation axis of the hub. The air outlet is located at the end of the third flow channel section away from the rotation axis of the hub.

20. The impeller according to any one of claims 1, 2, 5, 7, 8, 10-12, 14-18, characterized in that, The impeller also includes a reinforcing ring, which is coaxially arranged with the rotation axis of the hub, and the ends of all the blades of the impeller away from the rotation axis of the hub are fixedly connected by the reinforcing ring.

21. The impeller according to claim 3, characterized in that, The impeller also includes a reinforcing ring, which is coaxially arranged with the rotation axis of the hub, and the ends of all the blades of the impeller away from the rotation axis of the hub are fixedly connected by the reinforcing ring.

22. The impeller according to claim 4, characterized in that, The impeller also includes a reinforcing ring, which is coaxially arranged with the rotation axis of the hub, and the ends of all the blades of the impeller away from the rotation axis of the hub are fixedly connected by the reinforcing ring.

23. The impeller according to claim 6, characterized in that, The impeller also includes a reinforcing ring, which is coaxially arranged with the rotation axis of the hub, and the ends of all the blades of the impeller away from the rotation axis of the hub are fixedly connected by the reinforcing ring.

24. The impeller according to claim 9, characterized in that, The impeller also includes a reinforcing ring, which is coaxially arranged with the rotation axis of the hub, and the ends of all the blades of the impeller away from the rotation axis of the hub are fixedly connected by the reinforcing ring.

25. The impeller according to claim 13, characterized in that, The impeller also includes a reinforcing ring, which is coaxially arranged with the rotation axis of the hub, and the ends of all the blades of the impeller away from the rotation axis of the hub are fixedly connected by the reinforcing ring.

26. The impeller according to claim 19, characterized in that, The impeller also includes a reinforcing ring, which is coaxially arranged with the rotation axis of the hub, and the ends of all the blades of the impeller away from the rotation axis of the hub are fixedly connected by the reinforcing ring.

27. A centrifugal fan, characterized in that, It includes a volute and an impeller as described in any one of claims 1-26, wherein the impeller is mounted inside the volute and the hub of the impeller is rotatably connected to the volute.

28. An electronic device, characterized in that, It includes a housing and a centrifugal fan as described in claim 27, wherein the volute of the centrifugal fan is mounted on the housing.

Images