Fan and electronic device

Abstract

The application discloses a fan and electronic equipment, wherein the fan comprises a shell and an impeller rotatably arranged in the shell; wherein the impeller comprises a disc, and a plurality of first blades and a plurality of second blades fixed opposite to the disc, the plurality of first blades are sequentially arranged along the circumference of the disc, the second blades are arranged between part of the adjacent first blades, and the length of the second blades in the radial direction of the disc is smaller than that of the first blades; the first included angle formed by the adjacent first blades is proportional to the first area thereof, and the first area is positively correlated with the sweeping area capable of being formed by the adjacent first blades. The spacing between the adjacent first blades of the fan is positively correlated with the sweeping area capable of being formed by the adjacent first blades, so that the flow and air pressure of the airflow between each pair of adjacent first blades are balanced, the air flow and air pressure of the fan are optimized, and the noise performance of the fan is improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of electronic equipment, in particular to a fan and electronic equipment. BACKGROUND

[0002] Electronic equipment such as notebook computers, desktop computers and the like usually adopts a fan as a heat dissipation device. The fan is usually connected with a heat generating component of the electronic equipment through a heat conducting component. The heat conducting component guides the heat generated by the heat generating component to the fan. The fan guides the flow of air to carry away the heat, so as to avoid the temperature of the heat generating component being too high and ensure the normal operation of the electronic equipment. With the development of the related technology of electronic equipment, the processing performance of the electronic equipment is getting higher and higher, and the heat generated by the heat generating component is also getting larger and larger. Therefore, higher requirements are put forward for the heat dissipation performance of the fan. At the same time, the fan is usually the main noise source of the electronic equipment. Too large noise will inevitably affect the user experience. Therefore, how to improve the heat dissipation performance of the fan and take into account the noise level of the fan has become the common direction of efforts of the technical personnel in the field. SUMMARY

[0003] The present application provides a fan and electronic equipment. The technical solutions adopted by the embodiments of the present application are as follows:

[0004] A fan includes a housing and an impeller rotatably arranged in the housing. The impeller includes a disc, and a plurality of first blades and a plurality of second blades fixed opposite to the disc. The plurality of first blades are sequentially arranged along the circumference of the disc, and the second blades are arranged between part of adjacent first blades. The length of the second blades in the radial direction of the disc is smaller than that of the first blades.

[0005] The first included angle formed by adjacent first blades is proportional to the first area thereof. The first area is positively correlated with the wind sweeping area that can be formed by adjacent first blades.

[0006] In some embodiments, the first included angle is the included angle between the root ends of adjacent first blades with the center point of the disc as the vertex.

[0007] If the second blades are not arranged between adjacent first blades, the first area is the sum of the cross-sectional areas of the two adjacent first blades. If the second blades are arranged between adjacent first blades, the first area is the sum of the cross-sectional areas of the two adjacent first blades and the second blades arranged therebetween.

[0008] In some embodiments, the root ends of the first blades are connected with the circumferential part of the disc, the root ends of the second blades are in a mutually separated state with the disc, and the first blades and the second blades are relatively fixed through a first connecting component.

[0009] In some embodiments, the tip of the first blade and the tip of the second blade both extend to a first circumference, and the center of the first circumference overlaps with the center line of the wheel disc.

[0010] In some embodiments, the first connecting component extends along an annular area close to the tip of the first blade and connects with each of the first blade and the second blade.

[0011] In some embodiments, the root of the first blade and the root of the second blade are both connected with the periphery of the wheel disc, the tip of the first blade extends to a first circumference, the tip of the second blade extends to a second circumference, the center of the first circumference and the center of the second circumference both overlap with the center line of the wheel disc, and the radius of the first circumference is greater than the radius of the second circumference.

[0012] In some embodiments, the impeller further comprises a plurality of second connecting components arranged along a third circumference in sequence and a plurality of third connecting components arranged along a fourth circumference in sequence; the second connecting components are fixedly connected with the tips of a plurality of consecutive first blades; the third connecting components are fixedly connected with the tips of the second blades, and the third connecting components are respectively connected with the first blades located on both sides of the second blades.

[0013] In some embodiments, the center of the third circumference and the center of the fourth circumference both overlap with the center line of the wheel disc, the radius of the third circumference is greater than the radius of the second circumference, and the radius of the fourth circumference is less than or equal to the radius of the second circumference.

[0014] In some embodiments, the end wall of the shell is opposite to the end surface of the impeller, and the end wall of the shell is provided with an air inlet, and the area close to the periphery of the end surface of the impeller is covered with an annular baffle.

[0015] In some embodiments, the inner side of the end wall of the shell is provided with an annular wind baffle, the annular wind baffle extends along the circumference of the impeller and blocks at least part of the gap between the end wall of the shell and the end surface of the impeller.

[0016] An electronic device comprising the fan as claimed in any one of the above embodiments.

[0017] The fan of the embodiment of the present application, the impeller includes first blades and second blades with different lengths in the radial direction of the impeller, a plurality of first blades are sequentially arranged along the axial direction of the disc, and the second blades are arranged between part of adjacent first blades to improve the flow and air pressure of the airflow that can be guided during the rotation of the impeller. The first included angle formed by adjacent first blades is proportional to the first area thereof, so the spacing between adjacent first blades is proportional to the air sweeping area that can be formed by adjacent first blades, so that the flow and air pressure of the airflow between each pair of adjacent first blades are balanced, the airflow backflow caused by unbalanced flow and air pressure can be avoided, the air flow and air pressure of the fan are optimized, noise spectrum can be dispersed, and the noise performance of the fan is improved. BRIEF DESCRIPTION OF DRAWINGS

[0018] Figure 1 FIG. 1 is a perspective view of a fan according to a first embodiment of the present application;

[0019] Figure 2 FIG. 2 is a top view of an impeller according to the first embodiment of the present application;

[0020] Figure 3 FIG. 3 is a perspective view of the impeller according to the first embodiment of the present application from a different angle; Figure 4

[0021] FIG. 4 is a top view of an impeller according to a second embodiment of the present application; Figure 5

[0022] FIG. 5 is a perspective view of the impeller according to the second embodiment of the present application from a different angle; Figure 6 Figure 7 FIG. 6 is a top view of an impeller according to a third embodiment of the present application;

[0023] Figure 8 FIG. 7 is a side view of a fan according to the third embodiment of the present application;

[0024] Figure 9 FIG. 8 is a C-C sectional view of the fan in FIG. 7;

[0025] Figure 10 Figure 9 FIG. 9 is an exploded view of the fan in FIG. 7.

[0026] Figure 11 FIG. 10 is a perspective view of the fan in FIG. 7 from a different angle.

[0027] REFERENCE SIGNS:

[0028] 10 - housing; 11 - air inlet; 12 - air outlet; 13 - annular baffle ring;

[0029] ​​20 - impeller; 21 - wheel disc; 22 - first blade; 23 - second blade; 24 - first connecting member; 25 - second connecting member; 26 - third connecting member; 27 - ring baffle. DETAILED DESCRIPTION

[0030] Various aspects and features of the present application are described herein with reference to the drawings.

[0031] It is to be understood that various alterations, modifications, and improvements can be made to the embodiments of the application herein disclosed. Accordingly, it is intended to embrace all such alterations, modifications, and improvements as fall within the scope and spirit of the application.

[0032] The accompanying drawings incorporated in and forming a part of the specification illustrate embodiments of the present application and, together with the general description of the application given above, and the detailed description of the embodiments given below, serve to explain the principles of the present application.

[0033] These and other characteristics of the present application will become apparent from the following description and appended claims, taken in conjunction with the accompanying drawings.

[0034] It should be understood that every embodiment of the application that is not specifically described herein is not intended to be excluded "as long as such embodiments are within the scope and spirit of the present application.

[0035] The above and other aspects, features, and advantages of the present application will become more apparent from the following detailed description when taken in conjunction with the accompanying drawings in which:

[0036] Specific embodiments of the present application are described herein with reference to the accompanying drawings. However, it should be understood that the disclosed embodiments are merely examples of implementing the present application and that a person of ordinary skill in the art would be able to devise many alternative ways of practicing the present application without departing from the scope and spirit of the present application. DETAILED DESCRIPTION

[0037] The specification can use phrases such as "in one embodiment", "in another embodiment", "in yet another embodiment", or "in other embodiments" which can refer to one or more of the same or different embodiments of the application.

[0038] The fan provided by the embodiments of the present application can be applied to electronic devices such as notebook computers, all-in-one computers or desktop computers as a heat dissipation device, and can also be applied to other devices for guiding airflow.

[0039] Referring to Figures 1 to 4 As shown in the figure, the fan provided by the embodiments of the present application comprises a housing 10 and an impeller 20. The housing 10 can have an air inlet 11 and an air outlet 12. For example, the housing 10 can have a flat volute shape, and the housing 10 can have two opposite end faces and a circumferential surface defined between the two end faces. The air inlet 11 can be arranged on the end face of the housing 10, and the air outlet 12 can be arranged on the circumferential surface of the housing 10. Of course, the housing 10 can also have other shapes, and the air inlet 11 and the air outlet 12 can also be arranged at other positions of the housing 10, and the specific shape and structure of the housing 10 are not limited herein.

[0040] The impeller 20 is rotatably arranged in the housing 10. The impeller 20 can comprise a disc 21, a plurality of first blades 22 and a plurality of second blades 23. The plurality of first blades 22 and the plurality of second blades 23 are fixed to the disc 21. The plurality of first blades 22 are arranged along the circumference of the disc 21 in sequence. The second blades 23 are arranged between some adjacent first blades 22. The length of the second blades 23 in the radial direction of the disc 21 is less than the length of the first blades 22. It can be understood that the adjacent first blades 22 include direct adjacent first blades 22 without the second blades 23 arranged therebetween, and also include indirectly adjacent first blades 22 with one or more second blades 23 arranged therebetween.

[0041] The first included angle formed by the adjacent first blades 22 is proportional to the first area thereof. The first area is positively correlated with the sweeping area that can be formed by the adjacent first blades 22. The first included angle formed by the adjacent first blades 22 is proportional to the spacing between the adjacent first blades 22. The first area can be determined based on the cross-sectional area of the adjacent first blades 22, so the first area is positively correlated with the sweeping area that can be formed by the adjacent first blades 22. In this way, the spacing between the adjacent first blades 22 is proportional to the sweeping area that can be formed by the adjacent first blades 22. It can be understood that the sweeping area that can be formed by the adjacent first blades 22 includes the sweeping area formed by the adjacent first blades 22 and the blades located therebetween.

[0042] The fan of the embodiment of the present application, the impeller 20 includes first blades 22 and second blades 23 with different lengths in the radial direction of the impeller 20, a plurality of first blades 22 are sequentially arranged along the axial direction of the disc 21, and the second blades 23 are arranged between some adjacent first blades 22 to improve the flow rate and air pressure of the airflow that can be guided during the rotation of the impeller 20. The first included angle formed by the adjacent first blades 22 is proportional to the first area thereof, so the spacing between the adjacent first blades 22 is proportional to the wind sweeping area that can be formed by the adjacent first blades 22, so that the flow rate and air pressure of the airflow between each pair of adjacent first blades 22 are balanced, the airflow backflow caused by the unbalanced flow rate and air pressure can be avoided, the air outflow rate and air pressure of the fan are optimized, the noise spectrum can be dispersed, and the noise performance of the fan is improved.

[0043] In some embodiments, the first included angle can be an included angle between the root ends of the adjacent first blades 22 with the center point of the disc 21 as the vertex. The center point of the disc 21 can be a point on the center line of the disc 21 in the same cross section as the root ends of the first blades 22, and the cross section is a cross section perpendicular to the center line of the disc 21. Actually, the first included angle is the central angle of the root ends of the adjacent first blades 22 in the cross section. In the case where no second blade 23 is arranged between the adjacent first blades 22, the first included angle is shown in FIG. 1A and can be denoted as θ Figure 2 A In the case where the second blade 23 is arranged between the adjacent first blades 22, the first included angle is shown in FIG. 1B and can be denoted as θ Figure 2 B Generally, the adjacent first blades 22 gather to each other and the spacing therebetween gradually decreases during the extension of the adjacent first blades 22 to the center line of the disc 21, and the adjacent first blades 22 spread to each other and the spacing therebetween gradually increases during the extension of the adjacent first blades 22 to the periphery of the impeller 20. Configuring the central angle of the root ends of the adjacent first blades 22 in the cross section to be proportional to the first area makes the spacing between the root ends of the adjacent first blades 22 proportional to the first area, and the gap area between the adjacent first blades 22 is proportional to the wind sweeping area that can be formed by the adjacent first blades 22, so that the flow rate and air pressure of the airflow between each pair of adjacent first blades 22 are balanced, and industrial production and design are facilitated.

[0044] ​​In some embodiments, if the second vane 23 is not arranged between the adjacent first vanes 22, the first area can be the sum of the cross-sectional areas of the two adjacent first vanes 22; if the second vane 23 is arranged between the adjacent first vanes 22, the first area can be the sum of the cross-sectional areas of the two adjacent first vanes 22 and the cross-sectional area of the second vane 23 between the two adjacent first vanes 22. It should be noted that the cross section is a section perpendicular to the center line direction of the wheel disc 21. If the cross-sectional area of the first vane 22 is denoted as S1, the cross-sectional area of the second vane 23 is denoted as S2, the first area is S1*2 when the second vane 23 is not arranged between the adjacent first vanes 22, and the first area is S1*2+S2 when one second vane 23 is arranged between the adjacent first vanes 22. The first included angle formed by the adjacent first vanes 22 is proportional to the first area thereof, which can be expressed as: (S1*2) / (S1*2+S2)=θ A / θ B The cross-sectional area of the vane not only can directly affect the air sweeping area, but also is easy to control and easy to realize industrial production and design.

[0045] In specific implementation, the connecting structure between the first vane 22, the second vane 23 and the impeller 20 can have multiple implementation modes, as long as the relative fixation of the first vane 22, the second vane 23 and the impeller 20 can be realized. The connecting structure and principle between the first vane 22, the second vane 23 and the impeller 20 are exemplarily described below in combination with some specific embodiments, but should not be understood as being limited to the relative fixation of the first vane 22, the second vane 23 and the impeller 20 through the following modes.

[0046] In combination Figures 2 to 4 As shown in the drawings, in some embodiments, the root end of the first vane 22 is connected with the peripheral portion of the wheel disc 21, the root end of the second vane 23 is in a mutually separated state with the wheel disc 21, and the first vane 22 and the second vane 23 are relatively fixed through the first connecting component 24. The spacing between the adjacent first vanes 22 gradually decreases during the extension toward the center line of the impeller 20, and the spacing between the adjacent first vanes 22 gradually increases during the extension toward the periphery of the impeller 20. The root portion of the first vane 22 is configured to be connected with the peripheral portion of the wheel disc 21, and the root portion of the second vane 23 is configured to be in a mutually separated state with the wheel disc 21, which can avoid the occupation of the gap between the root portions of the adjacent first vanes 22 by the second vane 23, so that the relatively larger gap between the root portions of the adjacent first vanes 22 can be maintained, which is beneficial to increase the flow and air pressure of the airflow.

[0047] Optionally, the wheel disc 21 can be in a cylindrical shape, and the root of the first blade 22 can be connected to the outer circumferential surface of the wheel disc 21. The root of the second blade 23 can be spaced apart from the outer circumferential surface of the wheel disc 21 by a first distance, and the second blade 23 can be fixed relative to the wheel disc 21 through the first connecting member 24 and the first blade 22.

[0048] Optionally, the first blade 22 and the second blade 23 can extend linearly along the radial direction of the wheel disc 21, or can extend approximately in a curved shape along the radial direction of the wheel disc 21. For example, the first blade 22 and the second blade 23 can both extend approximately in an S shape. Optionally, the first blade 22 and the second blade 23 can extend along the radial direction of the wheel disc 21 in substantially the same shape.

[0049] Optionally, one or more second blades 23 can be arranged every first number of first blades 22 in the circumferential direction of the wheel disc 21. For example, one second blade 23 can be arranged every three to five first blades 22 in the circumferential direction of the wheel disc 21.

[0050] Optionally, the second blades 23 can be arranged at equal intervals between adjacent first blades 22. That is, if one second blade 23 is arranged between adjacent first blades 22, the second blade 23 is spaced apart from the adjacent first blades 22 at the same interval. If multiple second blades 23 are arranged between adjacent first blades 22, the first blades 22 and the adjacent second blades 23 are spaced apart at the same interval, and the adjacent second blades 23 are also spaced apart at the same interval. In this way, the flow rate and pressure of the airflow can be balanced.

[0051] In some embodiments, the tip of the first blade 22 and the tip of the second blade 23 both extend to a first circle, as shown in FIG. 1. Figure 2 The center of the first circle overlaps the center line of the wheel disc 21, i.e., the axis of the wheel disc 21. The first circle is the circle on the cross section of the impeller 20, and the center line of the wheel disc 21 is the axis of the wheel disc 21. The tips of the first blades 22 and the tips of the second blades 23 are flush on the first circle, so that the impeller 20 has a neat peripheral line. Since the length of the second blade 23 is shorter, the tips of the second blades 23 are aligned with the tips of the first blades 22 on the first circle, which can maximize the gap in the middle of the impeller 20 and can avoid the second impeller 20 occupying the gap between the roots of the adjacent first blades 22 as much as possible.

[0052] In some embodiments, the first connecting member 24 extends along a ring region close to the tip of the first blade 22 and connects with each of the first blade 22 and the second blade 23. In this way, the first blade 22 and the second blade 23 can be relatively fixed as a whole by the first connecting member 24, so that the impeller 20 has better integrity, which is beneficial to suppress the vibration of the impeller 20, and further beneficial to reduce the noise caused by the fan.

[0053] Optionally, the first connecting member 24 can be in the shape of a ring, and the axis of the first connecting member 24 can coincide with the axis of the wheel disc 21. In this way, the mass distribution of the impeller 20 in each direction is balanced, which is beneficial to further suppress the vibration of the impeller 20. Optionally, in the axial direction of the impeller 20, the first connecting member 24 can be connected to the middle of the first blade 22 and the second blade 23, or can be connected to the side of the first blade 22 and the second blade 23.

[0054] Optionally, the outer diameter of the first connecting member 24 can be close to but smaller than the radius of the first circumference, so that the first connecting member 24 can extend close to the tip of the first blade 22 and the tip of the second blade 23. Optionally, the root of the second blade 23 can extend to the inner periphery of the first connecting member 24.

[0055] Optionally, the first blade 22, the second blade 23 and the first connecting member 24 can adopt an integrated structure. For example, the impeller 20 can be made of organic materials, and the first blade 22, the second blade 23 and the first connecting member 24, and even the wheel disc 21, can be processed by an integrated molding process such as injection molding. In this way, it is not only easy to produce and process, but also has higher integrity.

[0056] Cooperation Figures 5 to 7 As shown, in some embodiments, the root of the first blade 22 and the root of the second blade 23 are connected with the periphery of the wheel disc 21, the tip of the first blade 22 extends to the first circumference, and the tip of the second blade 23 extends to the second circumference. Among them, the first circumference and the second circumference are both circumferences on the cross section of the impeller 20, the center of the first circumference and the center of the second circumference both overlap with the center line of the wheel disc 21, and the radius of the first circumference is greater than the radius of the second circumference. In this way, the first blade 22 and the second blade 23 are directly connected with the wheel disc 21, and the blades as a whole are firmly connected with the wheel disc 21, so that the impeller 20 has higher stability, and the driving force can be directly transmitted to the first blade 22 and the second blade 23 during the rotation of the wheel disc 21, which is beneficial to suppress the vibration of the impeller 20, and further beneficial to reduce the noise.

[0057] In some embodiments, the impeller 20 further comprises a plurality of second connecting components 25 arranged along a third circumference and a plurality of third connecting components 26 arranged along a fourth circumference; the second connecting components 25 are fixedly connected to the tips of a plurality of continuous first blades 22; the third connecting components 26 are fixedly connected to the tips of the second blades 23, and the third connecting components 26 are respectively connected to the first blades 22 located on both sides of the second blades 23. The centers of the third circumference and the fourth circumference both overlap with the center line of the rotating disc, the radius of the third circumference is greater than the radius of the second circumference, the radius of the fourth circumference is less than or equal to the radius of the second circumference, and the third circumference and the fourth circumference can both be circumferences on the cross section of the rotating disc 21.

[0058] For example, along the circumferential direction of the impeller 20, one second blade 23 can be arranged after every three continuous first blades 22, the second connecting components 25 can be fixedly connected to the tips of the three continuous first blades 22, the middle part of the third connecting components 26 can be connected to the second blade 23, and the two ends of the third connecting components 26 respectively extend to both sides along the circumferential direction of the impeller 20 and are respectively connected to the first blades 22 on both sides of the second blade 23, so that the second blade 23 is fixedly connected to the adjacent first blades 22. In this way, the first blades 22 and the second blades 23 can be connected as a whole through the second connecting components 25 and the third connecting components 26.

[0059] Optionally, the second connecting components 25 and the third connecting components 26 can be in the form of a sheet. In the axial direction of the impeller 20, the second connecting components 25 and the third connecting components 26 can be connected to the sides of the first blades 22 and the second blades 23. Of course, the second connecting components 25 and the third connecting components 26 can also be connected to the middle parts of the first blades 22 and the second blades 23 in the axial direction of the impeller 20.

[0060] Cooperation Figure 8 As shown, in some embodiments, the end wall of the shell 10 is opposite to the end surface of the impeller 20, and the end wall of the shell 10 is provided with an air inlet 11, and the area close to the circumferential edge of the end surface of the impeller 20 is covered with an annular baffle 27. The air flow enters between the adjacent blades through the end surface of the impeller 20 and finally flows out through the circumferential part of the impeller 20. Under the shielding of the annular baffle 27, the air flow can be prevented from flowing back into the impeller 20 through the end surface of the impeller 20, so that the air flow is maximized to flow out through the air outlet 12 on the shell 10, thereby maximizing the air flow.

[0061] Optionally, the shell 10 can be flat and spiral-shaped, and an air inlet 11 can be arranged on one side end face or opposite side end faces of the shell 10, and an air outlet 12 can be arranged on the peripheral portion of the shell 10. In this way, the air flow enters the impeller 20 through the end portion of the shell 10, and flows out through the air outlet 12 on the peripheral portion of the shell 10 under the guidance of the impeller 20.

[0062] Fitting Figures 9 to 11 As shown, in some embodiments, an annular wind-blocking ring 13 is arranged on the inner side of the end wall of the shell 10, and extends along the circumference of the impeller 20 and blocks at least part of the gap between the end wall of the shell 10 and the end face of the impeller 20. In this way, the air flow flowing out through the peripheral portion of the impeller 20 can be further prevented from backflowing, thereby further improving the air output of the fan. Optionally, for example, an annular rubber ring can be arranged on the inner side of the end wall of the shell 10, and the gap between the end wall of the shell 10 and the end face of the impeller 20 is blocked by the annular rubber ring. In this way, the purpose of blocking the gap can be achieved, and the impeller 20 can be protected from damage caused by scratching the impeller 20. Optionally, the annular rubber ring can be attached to the end wall of the shell 10.

[0063] The embodiments of the present application also provide an electronic device, which can be, for example, a notebook computer, an all-in-one computer, a desktop computer or other electronic devices. The electronic device of the embodiments of the present application can include the fan as described in any one of the above.

[0064] Since the fan described above can balance the flow and pressure of the air flow between each pair of adjacent first blades 22, can avoid backflow caused by unbalanced flow, can optimize the air output flow and air pressure of the fan, and can also disperse the frequency spectrum, which is beneficial to improve the noise performance of the fan. Therefore, the electronic device applying the fan described above also has the advantages described above, has good heat dissipation effect, and has good noise performance.

[0065] For example, the electronic device can be, for example, a notebook computer, and the fan can be arranged on the system end of the notebook computer, and used for dissipating heat of heat sources such as central processing units and graphics processing units.

[0066] The above embodiments are only exemplary embodiments of the present application, and are not used to limit the present application, and the protection scope of the present application is defined by the claims. Those skilled in the art can make various modifications or equivalent replacements to the present application within the spirit and protection scope of the present application, and such modifications or equivalent replacements shall also be considered to fall within the protection scope of the present application.

Claims

1. A fan comprising a housing and an impeller rotatably disposed within the housing; wherein, The impeller comprises a disc and a plurality of first blades and a plurality of second blades fixed opposite to the disc, the plurality of first blades are sequentially arranged along the circumference of the disc, and the second blades are arranged between part of the adjacent first blades, and the length of the second blades in the radial direction of the disc is less than the length of the first blades; The first included angle formed by the adjacent first blades is proportional to the first area thereof, and the first area is positively correlated with the air sweeping area formed by the adjacent first blades; If the second blades are not arranged between the adjacent first blades, the first area is the sum of the cross-sectional areas of the two adjacent first blades; If the second blades are arranged between the adjacent first blades, the first area is the sum of the cross-sectional areas of the two adjacent first blades and the second blades arranged therebetween.

2. The fan of claim 1, wherein, The first included angle is the included angle between the root ends of the adjacent first blades with the center point of the disc as the vertex.

3. The fan of claim 1, wherein, The root ends of the first blades are connected to the circumferential part of the disc, the root ends of the second blades are in a mutually separated state with the disc, and the first blades and the second blades are relatively fixed by the first connecting members.

4. The fan of claim 3, wherein, The tip ends of the first blades and the tip ends of the second blades extend to a first circumference, and the center of the first circumference overlaps the center line of the disc.

5. The fan of claim 4, wherein, The first connecting members extend along the annular area close to the tip ends of the first blades and are connected to each of the first blades and the second blades.

6. The fan of claim 1, wherein, The root ends of the first blades and the root ends of the second blades are connected to the circumferential part of the disc, the tip ends of the first blades extend to a first circumference, the tip ends of the second blades extend to a second circumference, the center of the first circumference and the center of the second circumference both overlap the center line of the disc, and the radius of the first circumference is greater than the radius of the second circumference.

7. The fan of claim 6, wherein, The impeller further comprises a plurality of second connecting members sequentially and spaced apart along a third circumference, and a plurality of third connecting members sequentially and spaced apart along a fourth circumference; the second connecting members are fixedly connected to the tip portions of a plurality of consecutive first blades; the third connecting members are fixedly connected to the tip portions of the second blades, and the third connecting members are respectively connected to the first blades located on both sides of the second blades; The center of the third circumference and the center of the fourth circumference both overlap the center line of the disc, the radius of the third circumference is greater than the radius of the second circumference, and the radius of the fourth circumference is less than or equal to the radius of the second circumference.

8. The fan of any one of claims 1 to 7, wherein, The end wall of the shell is opposite to the end surface of the impeller, and the end wall of the shell is provided with an air inlet; and the area close to the circumferential edge of the end surface of the impeller is covered with an annular baffle.

9. The fan of claim 8, wherein, The inner side of the end wall of the shell is provided with an annular wind ring, which extends along the circumference of the impeller and blocks at least part of the gap between the end wall of the shell and the end surface of the impeller.

10. An electronic device comprising the fan according to any one of claims 1 to 9.

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