Impeller and fan

Abstract

This utility model provides an impeller and a fan, relating to the technical field of kitchen appliances. The impeller provided by this utility model includes: a central disc and a bushing. The bushing is coaxially connected to the central disc. The bushing is provided with a shaft hole for connecting to a motor shaft. A handle structure protruding outward is provided on the circumferential outer wall of the bushing. The protruding handle structure on the bushing provides a leverage point for maintenance workers. Maintenance workers can use their fingers to grip the handle structure, thereby pulling the impeller off the motor shaft, preventing the impeller from slipping out of their hands when pulling it out, thus facilitating the disassembly and maintenance of the impeller.

Description

Technical Field

[0001] This utility model relates to the field of kitchen appliance technology, and in particular to an impeller and a fan. Background Technology

[0002] The smoke hood contains a multi-blade centrifugal fan. The impeller is the core component of the multi-blade centrifugal fan. Its main function is to do work on the air by rotating, converting mechanical energy into the kinetic and pressure energy of the airflow.

[0003] The fan includes a volute, an impeller, a motor, and a motor bracket. The motor is connected to the volute via the motor bracket. The motor is fixedly connected to the impeller; specifically, the impeller has a bushing, which is placed on the motor shaft, and the motor drives the impeller to rotate.

[0004] During later maintenance of the fan, workers need to pull the impeller off the motor shaft. However, the existing impeller is not easy to remove, which leads to the problem of difficulty in separating the impeller from the motor. Utility Model Content

[0005] The purpose of this invention is to provide an impeller and a fan to alleviate the technical problem of inconvenient disassembly of the impeller in existing fans.

[0006] In a first aspect, the present invention provides an impeller comprising: a central disc and a bushing, wherein the bushing is coaxially connected to the central disc, the bushing is provided with a shaft hole for connecting to a motor shaft, and the bushing is provided with a handle structure protruding outward on its circumferential outer wall.

[0007] Furthermore, the number of handle structures is multiple along the circumference of the bushing.

[0008] Furthermore, the bushing and the middle plate are integrally formed by injection molding;

[0009] The middle plate is provided with mold through holes, which penetrate the opposite two side surfaces of the middle plate;

[0010] The mold perforation is located on the circumferential outer side of the bushing and is connected to the circumferential outer wall of the bushing. In a direction perpendicular to the middle plate, the projection of the handle structure on the middle plate is located on the inner side of the mold perforation or coincides with the mold perforation.

[0011] Furthermore, the mold perforation is configured to avoid fingers used to pull the handle structure.

[0012] Furthermore, the middle plate includes an upper surface and a lower surface facing opposite directions;

[0013] The impeller also includes an upper disk, upper blades, a lower disk, and lower blades;

[0014] The upper plate, middle plate, and lower plate are arranged at intervals along the axial direction;

[0015] Multiple upper blades are connected between the upper disk and the middle disk; multiple lower blades are connected between the lower disk and the middle disk;

[0016] The upper blade includes a first connecting end connected to the middle disk and a second connecting end connected to the upper disk; the lower blade includes a third connecting end connected to the middle disk and a fourth connecting end connected to the lower disk.

[0017] From the first connecting end to the second connecting end, the upper blade is inclined toward the first circumferential rotation direction of the middle disk; from the third connecting end to the fourth connecting end, the lower blade is inclined toward the first circumferential rotation direction of the middle disk.

[0018] Furthermore, along the direction from the first connecting end to the second connecting end, the cross-sectional shape of each position of the upper blade is the same, but the area of ​​the cross-section gradually decreases.

[0019] Along the direction from the third connecting end to the fourth connecting end, the cross-sectional shape of each position of the lower blade is the same, but the area of ​​the cross-section gradually decreases.

[0020] Furthermore, the angle between the length direction of the upper blade and the axis of the middle disk is α1; the angle between the length direction of the lower blade and the axis of the middle disk is α2, 3°≤α1≤15°, 3°≤α2≤15°;

[0021] Furthermore, the cross-sectional shape of both the upper blade and the lower blade includes concave and convex surfaces arranged opposite to each other, with the concave surface of one upper blade facing the convex surface of the adjacent upper blade; and the concave surface of one lower blade facing the convex surface of the adjacent lower blade.

[0022] Along the axial direction of the middle disk, the projection of the convex surface at the first connecting end of the same upper blade onto the middle disk is the first arc surface, and the projection of the convex surface at the second connecting end onto the middle disk is the second arc surface. The angle between the axis of the middle disk and the tangents formed by the first arc surface and the second arc surface is β1, where 0°<β1≤α1≤20°.

[0023] Along the axial direction of the middle disk, the projection of the convex surface at the location of the third connecting end of the same lower blade onto the middle disk is the third arc surface, and the projection of the convex surface at the location of the fourth connecting end onto the middle disk is the fourth arc surface. The angle between the axis of the middle disk and the tangents formed by the third arc surface and the fourth arc surface is β2, where 0°<β2≤α2≤20°.

[0024] Furthermore, the middle plate is provided with injection holes penetrating its front and rear surfaces; there are multiple injection holes along the circumference of the middle plate; the upper surface of the middle plate is provided with a flow-blocking groove that is recessed towards the lower surface, the flow-blocking groove is located radially outside the injection hole, and the flow-blocking groove is located at the root of the upper blade at the middle position of two adjacent injection holes in the circumferential direction.

[0025] And / or, the upper surface of the middle disk is provided with a protruding first reinforcing rib, the first reinforcing rib including a first segment and a second segment extending radially along the middle disk, the radial inner end of the first segment being connected to the bushing, the radial outer end of the first segment being connected to the second segment, the first segment protruding in a direction perpendicular to the upper surface, and the protrusion direction of the second segment being consistent with the tilt direction of the upper blade; and / or, the lower surface of the middle disk is provided with a protruding second reinforcing rib, the second reinforcing rib including a third segment and a fourth segment extending radially along the middle disk, the radial inner end of the third segment being connected to the bushing, the radial outer end of the third segment being connected to the fourth segment, the third segment protruding in a direction perpendicular to the lower surface, and the protrusion direction of the fourth segment being consistent with the tilt direction of the lower blade.

[0026] Secondly, the present invention provides a fan including the aforementioned impeller.

[0027] This utility model has at least the following advantages or beneficial effects:

[0028] The impeller provided by this utility model includes: a central disk and a bushing, the bushing being coaxially connected to the central disk, the bushing having a shaft hole for connecting to a motor shaft, and the bushing having a handle structure protruding outward on its circumferential outer wall.

[0029] The protruding handle on the bushing provides a leverage point for maintenance workers. They can use their fingers to grip the handle and pull the impeller off the motor shaft, preventing the impeller from slipping out of their hands when removing it, thus facilitating the disassembly and maintenance of the impeller.

[0030] The fan provided by this utility model includes the aforementioned impeller. Because the fan provided by this utility model uses the aforementioned impeller, it also possesses the advantages of an impeller. Attached Figure Description

[0031] To more clearly illustrate the specific embodiments of this utility model or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this utility model. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0032] Figure 1 A schematic diagram of the impeller provided for an embodiment of this utility model;

[0033] Figure 2 A side view of the impeller provided in an embodiment of this utility model;

[0034] Figure 3 A cross-sectional view of the impeller provided in an embodiment of this utility model;

[0035] Figure 4 for Figure 3 A magnified view of a portion of position A in the middle;

[0036] Figure 5 A schematic diagram of the upper surface of the impeller provided in an embodiment of the present utility model;

[0037] Figure 6 for Figure 5 A magnified view of a portion of position B in the middle;

[0038] Figure 7 A schematic diagram of the lower surface of the impeller provided in an embodiment of this utility model;

[0039] Figure 8 for Figure 3 A cross-sectional view along the CC direction;

[0040] Figure 9 for Figure 3 A cross-sectional view along the DD direction.

[0041] Icons: 1-Bushing; 2-Shaft hole; 3-Handle structure; 4-Middle plate; 5-Mold through hole; 6-Upper surface; 7-Lower surface; 8-Upper plate; 9-Upper blade; 10-Lower plate; 11-Lower blade; 12-First connecting end; 13-Second connecting end; 14-Third connecting end; 15-Fourth connecting end; 16-Third arc surface; 17-Fourth arc surface; 18-Injection hole; 19-Cutting groove; 20-First section; 21-Second section; 22-Limiting groove; 23-First reinforcing rib. Detailed Implementation

[0042] To make the objectives, technical solutions, and advantages of the embodiments of this utility model clearer, the technical solutions of the embodiments of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this utility model, and not all embodiments. The components of the embodiments of this utility model described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0043] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0044] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0045] In the description of this utility model, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship commonly used when the product of this utility model is in use. They are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model. In addition, the terms "first," "second," and "third," etc., are only used to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0046] Furthermore, terms such as "horizontal" and "vertical" do not imply that components must be absolutely horizontal or suspended, but rather that they can be slightly tilted. For example, "horizontal" simply means that its direction is more horizontal than "vertical," and does not mean that the structure must be completely horizontal, but can be slightly tilted.

[0047] In the description of this utility model, it should also be noted that, unless otherwise explicitly specified and limited, the terms "set," "install," "connect," and "link" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances.

[0048] like Figures 1-9 As shown, the impeller provided by this utility model includes a central disk 4 and a bushing 1. The bushing 1 is located in the middle of the central disk 4, and the two are coaxially arranged.

[0049] like Figure 4 As shown, the bushing 1 is provided with a shaft hole 2 for connecting to the motor shaft, and the bushing 1 is also provided with a limiting groove 22. The limiting groove 22 is engaged with the limiting protrusion of the motor shaft. After the motor shaft is connected to the bushing 1, it can drive the impeller to rotate.

[0050] Unlike existing technologies, such as Figure 1 and Figure 4 As shown in this embodiment, the bushing 1 has a handle structure 3 protruding outward on its circumferential outer wall. The protruding handle structure 3 on the bushing 1 provides a leverage point for maintenance workers. Maintenance workers can use their fingers to grip the handle structure 3 to pull the impeller off the motor shaft, preventing the impeller from slipping out of their hands when pulling it out, thus facilitating the disassembly and maintenance of the impeller.

[0051] Along the circumference of the bushing 1, there are multiple handle structures 3, which are spaced apart. In this embodiment, there are three handle structures 3, which makes it convenient for maintenance workers to pull the impeller in any posture.

[0052] The bushing 1 and the middle plate 4 can be integrally molded by injection molding. The injection molding material is plastic. During the injection molding process, the mold forming part of the bushing 1 cannot directly form the handle structure 3, so another mold is needed to assist in completing the handle structure 3. During demolding, the mold forming the side of the handle structure 3 facing the middle plate 4 is withdrawn axially, leaving a mold through hole 5 on the middle plate 4. The mold through hole 5 penetrates the opposite two side surfaces of the middle plate 4. The mold through hole 5 is located on the circumferential outer side of the bushing 1, and the mold through hole 5 is connected to the circumferential outer wall of the bushing 1. That is, a part of the circumferential outer wall of the bushing 1 forms the outer wall of the mold through hole 5.

[0053] Along a direction perpendicular to the middle plate 4, the projection of the handle structure 3 on the middle plate 4 is located inside the mold through hole 5 or coincides with the mold through hole 5.

[0054] like Figure 4 As shown, during demolding, the projection of the handle structure 3 on the middle plate 4 coincides with the mold perforation 5. However, after demolding, the mold perforation 5 can be processed again to increase its size so that the mold perforation 5 is set to avoid the fingers used to pull the handle structure 3. The shape and size of the mold perforation 5 can be set to allow the fingers to pass through completely, or it can be set to prevent the fingers from passing through. However, the hole structure can still form a certain backward recessed avoidance space behind the handle structure 3 to avoid the fingers and prevent the fingers of maintenance personnel with long fingers from being blocked by the middle plate 4 of the impeller when picking up the handle structure 3.

[0055] like Figures 5-7 As shown, the middle disk 4 includes an upper surface 6 and a lower surface 7 facing opposite directions, and the impeller also includes an upper disk 8, an upper blade 9, a lower disk 10 and a lower blade 11, which can be integrally formed by injection molding.

[0056] The upper plate 8, middle plate 4, and lower plate 10 are arranged sequentially at intervals along the axial direction, providing support. Multiple upper blades 9 are connected between the upper plate 8 and the middle plate 4; multiple lower blades 11 are connected between the lower plate 10 and the middle plate 4. Figure 2 As shown, the upper blade 9 includes a first connecting end 12 connected to the middle disk 4 and a second connecting end 13 connected to the upper disk 8; the lower blade 11 includes a third connecting end 14 connected to the middle disk 4 and a fourth connecting end 15 connected to the lower disk 10. After the impeller rotates, the upper blade 9 and the lower blade 11 can form negative pressure from the upper and lower sides.

[0057] From the first connecting end 12 to the second connecting end 13, the upper blade 9 is inclined toward the first circumferential rotation direction of the middle disk 4; from the third connecting end 14 to the fourth connecting end 15, the lower blade 11 is inclined toward the first circumferential rotation direction of the middle disk 4. The upper blade 9 and the lower blade 11 are inclined in the same direction of rotation, either clockwise or counterclockwise of the middle disk 4.

[0058] Specifically, such as Figure 2 As shown, after the upper blade 9 and lower blade 11 are tilted and rotated, the angle between the length direction of the upper blade 9 and the axis of the middle disk 4 is α1; the angle between the length direction of the lower blade 11 and the axis of the middle disk 4 is α2, where 3°≤α1≤15° and 3°≤α2≤15°, thereby improving air performance and reducing the operating noise of the fan. α1 can be equal to or unequal to α2. The corresponding upper blade 9 and lower blade 11 are arranged in a "V" shape. The tilt angle and symmetry of the "V" shaped upper blade 9 and lower blade 11 can guide the fluid to transition smoothly along the surface of the upper blade 9 and lower blade 11, avoiding flow separation (boundary layer detachment) caused by abrupt curvature changes at the turning point of straight blades (in the prior art, blades perpendicular to the middle disk are called straight blades).

[0059] Along the direction from the first connecting end 12 to the second connecting end 13, the cross-sectional shape of each position of the upper blade 9 is the same, but the cross-sectional area gradually decreases; along the direction from the third connecting end 14 to the fourth connecting end 15, the cross-sectional shape of each position of the lower blade 11 is the same, but the cross-sectional area gradually decreases, which facilitates demolding during injection molding.

[0060] Specifically, such as Figure 8 and Figure 9As shown, the cross-sectional shape of the upper blade 9 and the lower blade 11 both include concave and convex surfaces arranged opposite to each other, with the concave surface of one upper blade 9 facing the convex surface of the adjacent upper blade 9; and the concave surface of one lower blade 11 facing the convex surface of the adjacent lower blade 11. Along the axial direction of the middle disk 4, the projection of the convex surface at the location of the first connecting end 12 of the same upper blade 9 onto the middle disk 4 is a first arc surface, and the projection of the convex surface at the location of the second connecting end 13 onto the middle disk 4 is a second arc surface. The angle between the axis of the middle disk 4 and the tangents formed by the first and second arc surfaces is β1, where 0° < β1 ≤ α1 ≤ 20°. Along the axial direction of the middle disk 4, the projection of the convex surface at the location of the third connecting end 14 of the same lower blade 11 onto the middle disk 4 is a third arc surface 16, and the projection of the convex surface at the location of the fourth connecting end 15 onto the middle disk 4 is a fourth arc surface 17. The angle between the axis of the middle disk 4 and the tangents formed by the third arc surface 16 and the fourth arc surface 17 is β2, where 0° < β2 ≤ α2 ≤ 20°.

[0061] Taking the upper blade 9 as an example, the oil fume airflow ejected by the upper blade 9 has a certain phase difference. The oil fume airflow is ejected sequentially and interacts with the volute tongue, thereby reducing the impact of the oil fume airflow on the volute tongue and further reducing the noise pollution generated by the fan operation. When the impeller rotates, the multiple flow channels formed by multiple adjacent upper blades 9 alternately expand and contract in space, making the pressure changes of the fluid periodically complementary in time. For example, when the pressure of one flow channel increases due to contraction, the adjacent flow channel may be in the expansion stage (pressure decreases). This alternating pressure change cancels each other out as a whole, thereby reducing the pressure pulsation amplitude within the flow channel.

[0062] Taking the upper blade 9 as an example, in the prior art, the cross-sectional shape of the upper blade 9 is an arc; while in this embodiment, the cross-sectional shape of the upper blade 9 is an arc airfoil structure, such as various airfoils of the NACA series.

[0063] Compared to existing arc-shaped "V"-shaped impellers, the airfoil-shaped "V"-shaped impeller in this embodiment increases the maximum static pressure by 10 Pa to 50 Pa and the maximum airflow by 0.1 m³. 3 / min -0.5m 3 / min, the maximum total pressure efficiency is increased by 1%-3%, and the operating noise is reduced by 0.2dB(A)-1dB(A).

[0064] like Figure 1 , Figure 5 and Figure 7As shown, the impeller is integrally formed by injection molding. During the injection molding process, the middle disk 4 serves as the interface, with the upper blade 9 and upper disk 8 located above the middle disk 4, and the lower blade 11 and lower disk 10 located below the middle disk 4. The tube that injects raw material into the middle disk 4 will form injection holes 18 on the middle disk 4 after the impeller is formed. There are multiple injection holes 18 along the circumference of the middle disk 4; in this embodiment, there are three.

[0065] like Figure 7 As shown, during the injection molding of the impeller, a flow-blocking groove 19 is also provided on the upper surface (upper surface 6) of the middle disk 4 facing upward, which is recessed to the other side (lower surface 7). In the radial direction, the flow-blocking groove 19 is located on the radial outer side of the injection hole 18, and in the circumferential direction, the flow-blocking groove 19 is located at the root of the upper blade 9 at the middle position of two adjacent injection holes 18 in the circumferential direction.

[0066] like Figure 5 In this embodiment, the intercepting groove 19 is set on the upper surface 6 of the middle plate 4 and is located at the root of one of the upper blades 9 and between two adjacent injection holes 18. The raw material flowing in from the two adjacent injection holes 18 will diffuse, and the location of the intercepting groove 19 is exactly the location where it is concentrated and converged. During the injection molding process, the structure of forming the intercepting groove 19 in the mold can reduce the risk of overflow.

[0067] like Figure 6 As shown, the upper surface 6 of the middle plate 4 is provided with a protruding first reinforcing rib 23. The first reinforcing rib 23 includes a first segment 20 and a second segment 21 extending radially along the middle plate 4. The radial inner end of the first segment 20 is connected to the bushing 1, and the radial outer end of the first segment 20 is connected to the second segment 21. The first segment 20 protrudes in a direction perpendicular to the upper surface 6, and the protrusion direction of the second segment 21 is consistent with the tilt direction of the upper blade 9.

[0068] There are three first reinforcing ribs 23, which are used to strengthen the impeller. In this embodiment, the bushing 1 extends axially, while the upper blade 9 is inclined relative to the axial direction. Therefore, during injection molding, the molds forming the bushing 1 and the upper blade 9 are two different parts. During demolding, these two parts are demolded separately. Therefore, in the first reinforcing rib 23, the first segment 20 near the bushing 1 is formed by axial demolding, while the second segment 21 is formed by inclined demolding. There is a step difference at the connection between the first segment 20 and the second segment 21.

[0069] The lower surface 7 of the middle plate 4 is provided with a protruding second reinforcing rib. The second reinforcing rib includes a third segment and a fourth segment extending radially along the middle plate 4. The radially inner end of the third segment is connected to the bushing 1, and the radially outer end of the third segment is connected to the fourth segment. The third segment protrudes in a direction perpendicular to the lower surface 7, and the protruding direction of the fourth segment is consistent with the tilting direction of the lower blade 11. The formation method of the second reinforcing rib can be the same as that of the first reinforcing rib 23, and the principle will not be repeated.

[0070] In this embodiment, the first reinforcing rib 23 is provided only on the upper surface 6, but in other feasible solutions, the second reinforcing rib can also be provided on the lower surface 7.

[0071] In this embodiment, the first reinforcing rib 23 covers a portion of the injection hole 18, providing stronger reinforcement to the injection hole 18.

[0072] The fan provided by this utility model includes the aforementioned impeller. Because the fan provided by this utility model uses the aforementioned impeller, it also possesses the advantages of an impeller.

[0073] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this utility model, and are not intended to limit it. Although the utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this utility model.

Claims

1. An impeller comprising: The middle plate (4) and the bushing (1) are coaxially connected to the middle plate (4). The bushing (1) is provided with a shaft hole (2) for connecting to the motor shaft. The bushing (1) is characterized by having a handle structure (3) protruding outward on the circumferential outer wall of the bushing (1).

2. The impeller of claim 1, wherein The number of handle structures (3) is multiple along the circumference of the bushing (1).

3. The impeller of claim 1, wherein The bushing (1) and the middle plate (4) are integrally formed by injection molding; The middle plate (4) is provided with a mold through hole (5), which penetrates the opposite two side surfaces of the middle plate (4); The mold perforation (5) is located on the circumferential outer side of the bushing (1), and the mold perforation (5) is connected to the circumferential outer wall of the bushing (1). Along the direction perpendicular to the middle plate (4), the projection of the handle structure (3) on the middle plate (4) is located on the inner side of the mold perforation (5) or coincides with the mold perforation (5).

4. The impeller according to claim 3, characterized in that, The mold perforation (5) is configured to avoid fingers used to pull the handle structure (3).

5. The impeller according to claim 3 or 4, characterized in that, The middle plate (4) includes an upper surface (6) and a lower surface (7) facing opposite directions. The impeller also includes an upper disk (8), an upper blade (9), a lower disk (10), and a lower blade (11). The upper plate (8), middle plate (4) and lower plate (10) are arranged sequentially at intervals along the axial direction; Multiple upper blades (9) are connected between the upper disk (8) and the middle disk (4); multiple lower blades (11) are connected between the lower disk (10) and the middle disk (4); The upper blade (9) includes a first connecting end (12) connected to the middle disk (4) and a second connecting end (13) connected to the upper disk (8); the lower blade (11) includes a third connecting end (14) connected to the middle disk (4) and a fourth connecting end (15) connected to the lower disk (10). From the first connecting end (12) to the second connecting end (13), the upper blade (9) is inclined toward the first circumferential rotation direction of the middle disk (4); from the third connecting end (14) to the fourth connecting end (15), the lower blade (11) is inclined toward the first circumferential rotation direction of the middle disk (4).

6. The impeller according to claim 5, characterized in that, Along the direction from the first connecting end (12) toward the second connecting end (13), the cross-sectional shape of each position of the upper blade (9) is the same, but the area of ​​the cross-section gradually decreases; Along the direction from the third connecting end (14) toward the fourth connecting end (15), the cross-sectional shape of each position of the lower blade (11) is the same, but the area of ​​the cross-section gradually decreases.

7. The impeller according to claim 6, characterized in that, The angle between the length direction of the upper blade (9) and the axis of the middle disk (4) is α1; the angle between the length direction of the lower blade (11) and the axis of the middle disk (4) is α2, 3°≤α1≤15°, 3°≤α2≤15°.

8. The impeller according to claim 7, characterized in that, The cross-sectional shape of the upper blade (9) and the lower blade (11) includes concave and convex surfaces arranged opposite to each other, with the concave surface of one upper blade (9) facing the convex surface of the adjacent upper blade (9); and the concave surface of one lower blade (11) facing the convex surface of the adjacent lower blade (11). Along the axial direction of the middle disk (4), the projection of the convex surface at the location of the first connecting end (12) of the same upper blade (9) onto the middle disk (4) is the first arc surface, and the projection of the convex surface at the location of the second connecting end (13) onto the middle disk (4) is the second arc surface. The angle between the axis of the middle disk (4) and the tangents formed by the first arc surface and the second arc surface is β1, where 0°<β1≤α1≤20°; Along the axial direction of the middle disk (4), the projection of the convex surface at the location of the third connecting end (14) of the same lower blade (11) onto the middle disk (4) is the third arc surface (16), and the projection of the convex surface at the location of the fourth connecting end (15) onto the middle disk (4) is the fourth arc surface (17). The angle between the axis of the middle disk (4) and the tangents formed by the third arc surface (16) and the fourth arc surface (17) is β2, where 0°<β2≤α2≤20°.

9. The impeller according to claim 5, characterized in that, The middle plate (4) is provided with injection holes (18) that penetrate its front and rear surfaces; there are multiple injection holes (18) along the circumference of the middle plate (4); the upper surface (6) of the middle plate (4) is provided with a flow intercepting groove (19) that is recessed into the lower surface (7); in the radial direction, the flow intercepting groove (19) is located on the radial outer side of the injection hole (18); in the circumference direction, the flow intercepting groove (19) is located at the root of the upper blade (9) at the middle position of two adjacent injection holes (18) in the circumference direction. And / or, the upper surface (6) of the middle disk (4) is provided with a protruding first reinforcing rib (23), the first reinforcing rib (23) includes a first segment (20) and a second segment (21) extending radially along the middle disk (4), the inner radial end of the first segment (20) is connected to the bushing (1), the outer radial end of the first segment (20) is connected to the second segment (21), the first segment (20) protrudes in a direction perpendicular to the upper surface (6), and the protrusion direction of the second segment (21) is consistent with the tilt direction of the upper blade (9); And / or, the lower surface (7) of the middle plate (4) is provided with a protruding second reinforcing rib, the second reinforcing rib including a third segment and a fourth segment extending radially along the middle plate (4), the inner radial end of the third segment being connected to the bushing (1), the outer radial end of the third segment being connected to the fourth segment, the third segment protruding in a direction perpendicular to the lower surface (7), and the protruding direction of the fourth segment being consistent with the tilting direction of the lower blade (11).

10. A fan, characterized in that, Includes the impeller as described in any one of claims 1-9.

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