Inner rotor axial flow fan

Abstract

The utility model relates to the technical field of fans, and discloses an inner rotor axial flow fan which comprises a motor, a hub and a plurality of blades, a motor shaft of the motor is sleeved with the hub, the hub is in key connection with the motor shaft, and blade roots of the blades are connected with the outer edge of the hub through fasteners. The blades are arranged on the outer edge of the hub through the fasteners, the hub is in key connection with the motor shaft of the rotor, compared with existing double-face welding connection of the blades and the rotor shell, the connecting mode is simple, assembling is convenient, deformation of the connecting position is small, the follow-up dynamic balancing procedure is convenient, and meanwhile the connecting quality and the assembling efficiency of connection of the blades and the rotor are improved.

Description

Technical Field

[0001] The utility model relates to the technical field of fans, and more specifically, to an inner rotor axial flow fan. Background Art

[0002] In the prior art, the blades of an inner rotor axial flow fan are mostly connected to the rotor housing by welding. Since the materials of the blades and the rotor housing are different, the welding is difficult and the operation is difficult.

[0003] Due to the insufficient welding strength of single-sided welding and discontinuous welding, double-sided welding is required to connect the rotor blades and the rotor housing, resulting in a large welding deformation and a large difference in the height of the blade tips, so that the initial unbalance of the fan is large, the dynamic balance is difficult and the efficiency is low, and even the situation of scrapping due to the inability to achieve dynamic balance may occur.

[0004] In summary, how to improve the connection quality between the blade and the rotor is an urgent problem to be solved by those skilled in the art at present. Summary of the Utility Model

[0005] In view of this, the purpose of the utility model is to provide an inner rotor axial flow fan, in which the blades are arranged on the outer edge of the hub through fasteners, and the hub is key-connected to the motor shaft of the rotor. The connection method is simple, the connection quality and assembly efficiency are high, which is beneficial to the subsequent dynamic balance trimming process.

[0006] In order to achieve the above purpose, the utility model provides the following technical solutions:

[0007] An inner rotor axial flow fan, comprising: a motor, a hub and a plurality of blades. The hub is sleeved outside the motor shaft of the motor, the hub is key-connected to the motor shaft, and the blade root of the blade is connected to the outer edge of the hub through a fastener.

[0008] Preferably, a blunt fillet is provided at the leading edge of the blade, and the radius Rt of the blunt fillet is 0.6-0.9T, where T is the blade body thickness of the blade.

[0009] Preferably, a continuous serrated notch is provided at the trailing edge of the blade.

[0010] Preferably, the radial distances between the inner vertices of any two adjacent serrated notches are the same, and the radial distances between the outer vertices of any two adjacent serrated notches are the same.

[0011] Preferably, the outer edge of the blade warps towards the back pressure surface, and the included angle γ between the warped surface and the back pressure surface gradually decreases from the trailing edge to the leading edge.

[0012] Preferably, the included angle γ between the warped surface and the back pressure surface satisfies 140°≤γ≤151°.

[0013] Preferably, the blade root of the blade is provided with a mounting hole, the outer edge of the hub is provided with a connection hole, and the blade and the hub are connected by riveting.

[0014] Preferably, a shaft sleeve for key connection with the motor shaft is provided in the center of the hub. The shaft sleeve is evenly provided with a number of twisted spokes along the circumferential direction, and the outer edge of the spoke is provided with the connection hole for connecting with the blade;

[0015] A reinforcing ring is provided between the shaft sleeve and the spoke to enhance the structural strength of the shaft sleeve.

[0016] Preferably, a continuous circle of reinforcing ribs is provided in the connection hole of the spoke, and the shape of the reinforcing rib is similar to the shape of the outer edge of the spoke.

[0017] For the internal rotor axial flow fan provided by the present utility model, the blade is arranged on the outer edge of the hub through a fastener, and the hub is key-connected to the motor shaft of the rotor, thereby realizing the connection between the blade and the rotor. Compared with the existing double-sided welding connection between the blade and the rotor housing, the connection method is simple, convenient for assembly, and the deformation amount at the connection is small, facilitating the subsequent dynamic balance trimming process, and at the same time improving the connection quality and assembly efficiency of the connection between the blade and the rotor.

[0018] In addition, the blade is connected to the rotor through the hub, enabling the rotor to change the type and quantity of the blade by replacing the hub, which is flexible and changeable, meeting the requirements of multi-scenario applications and facilitating product model change. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the technical solutions in the embodiments of the present utility model or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the drawings in the following description are only the embodiments of the present utility model, and for those of ordinary skill in the art, other drawings can be obtained according to the provided drawings without creative efforts.

[0020] Figure 1 is a schematic structural diagram of an internal rotor axial flow fan in the prior art;

[0021] Figure 2 is a longitudinal sectional schematic diagram of the internal rotor axial flow fan provided by the present utility model;

[0022] Figure 3 is an assembly schematic diagram of the blade and the hub;

[0023] Figure 4 is a schematic structural diagram of the blade;

[0024] Figure 5 is a sectional schematic diagram of the leading edge of the blade;

[0025] Figure 6 Is a schematic cross-sectional view of the outer edge of the blade;

[0026] Figure 7 Is a schematic structural view of the hub.

[0027] Figures 1 - 7 In:

[0028] 10 - Motor; 20 - Hub; 201 - Bush; 202 - Reinforcing ring; 203 - Spoke; 204 - Connecting hole; 205 - Reinforcing rib; 30 - Blade; 301 - Mounting hole; 302 is a blunt fillet; 303 - Serrated notch; 304 - Curved surface. Specific embodiments

[0029] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative work belong to the scope of protection of the present invention.

[0030] The core of the present invention is to provide an internal rotor axial flow fan. The blade is provided on the outer edge of the hub through fasteners, and the hub is key-connected to the motor shaft of the rotor. The connection method is simple, the connection quality and assembly efficiency are high, which is beneficial to the subsequent dynamic balance trimming process.

[0031] The internal rotor axial flow fan provided by the present invention includes: a motor 10, a hub 20, and a plurality of blades 30. The hub 20 is sleeved outside the motor shaft of the motor 10, the hub 20 is key-connected to the motor shaft, and the blade root of the blade 30 is connected to the outer edge of the hub 20 through fasteners.

[0032] Among them, the hub 20 is key-connected to the motor shaft of the motor 10. Here, the key connection includes double key connection and spline connection. The structure, shape, and size of the connection key are determined according to the connection strength requirements of the two in actual production.

[0033] The outer edge of the hub 20 is connected to the blade 30, thereby connecting the blade 30 and the motor 10; the hub 20 and the blade 30 can be connected by riveting or by common connectors such as fastening bolts and connecting pins;

[0034] Considering the assembly convenience, usually an installation hole 301 is provided at the blade root of the blade 30, a connection hole 204 is provided at the outer edge of the hub 20, and the blade 30 and the hub 20 are connected by riveting with rivets.

[0035] The hub 20 is preferably made of stainless steel by sheet metal stamping to meet the strength and design life requirements of the hub 20; the blade 30 can be either a metal blade such as an aluminum alloy blade or a non-metal blade.

[0036] The blade 30 is preferably provided with 3-9 blades. According to actual production, the optimal number of blades is 3, 4, 5 or 7. The specific material, shape and size of the blade 30 are determined by three-dimensional numerical simulation and / or wind tunnel experiments according to the design indexes in actual production, which will not be elaborated here.

[0037] In this embodiment, the blade 30 is provided on the outer edge of the hub 20 through a fastener, and the hub 20 is key-connected to the motor shaft of the rotor, thus realizing the connection between the blade 30 and the rotor. Compared with the existing double-sided welding connection, the connection method is simple, convenient for assembly, and the deformation at the connection is small, which facilitates the subsequent dynamic balance trimming process, and at the same time improves the connection quality and assembly efficiency of the connection between the blade 30 and the rotor.

[0038] In addition, the blade 30 is connected to the rotor through the hub 20, so that the rotor can change the type and number of the blade 30 by replacing the hub 20, which is flexible and changeable, meeting the requirements of multi-scenario applications and facilitating product model change.

[0039] Preferably, the blade 30 can be set as a forward-curved and backward-swept blade, which is beneficial to reasonably organize the flow field, improve the fan efficiency and improve the fan performance.

[0040] On the basis of the above embodiment, a blunt fillet 302 can be provided at the leading edge of the blade 30. The blunt fillet 302 can suppress the inlet eddy current, increase the inlet air volume, thereby improving the fan efficiency and reducing the noise. The radius Rt of the blunt fillet 302 is 0.6-0.9T, where T is the blade thickness of the blade 30.

[0041] On the basis of the above embodiment, a continuous serrated notch 303 can be provided at the trailing edge of the blade 30. The serrated notch 303 can stratify the air flow and suppress the outlet eddy current, thereby improving the fan efficiency and reducing the noise.

[0042] Usually, after the blade 30 is connected to the outer edge of the hub 20 through a fastener, the trailing edge of the blade 30 is serrated to avoid the stress generated by the connection affecting the performance of the serrated notch 303. Therefore, the serrated notch 303 is usually not provided at the blade root of the blade 30 for connecting to the hub 20.

[0043] Preferably, it can be set that the radial distance between the inner vertices of any two adjacent serrated notches is the same, and the radial distance between the outer vertices of any two adjacent serrated notches is the same, with a regular shape, which is convenient for the processing and manufacturing of the blade 30 and has a good eddy current suppression effect.

[0044] Please refer to Figure 3 , both the inner vertex and the outer vertex of the zigzag notch are located on the concentric circles with the hub center O as the center of the circle.

[0045] The radius Ri of the inner vertex of the zigzag notch is Ri = a + b * i, where i = 0, 1, 2, ……, n;

[0046] The radius Rj of the outer vertex of the zigzag notch is Rj = c + d * j, where j = 0, 1, 2, ……, n.

[0047] Among them, a, b, c, and d are all constants. a is the radius of the inner vertex of the zigzag notch closest to the hub center O, b is the radial distance between adjacent inner vertices of the zigzag notches, c is the radius of the outer vertex of the zigzag notch closest to the hub center O, and d is the radial distance between adjacent outer vertices of the zigzag notches.

[0048] The specific values of a, b, c, d, and the included angle α of the zigzag notch 303 are determined through three-dimensional numerical simulation and wind tunnel experiments according to the aerodynamic design indicators in actual production, which will not be elaborated here.

[0049] On the basis of the above embodiments, the outer edge of the blade 30 can be set to warp towards the back pressure surface, and the included angle γ between the warped surface 304 and the back pressure surface gradually decreases from the trailing edge to the leading edge to increase the strength of the blade 30, reduce eddy current loss and noise.

[0050] The value of the included angle γ between the warped surface 304 and the back pressure surface is determined through three-dimensional numerical simulation and wind tunnel experiments according to the aerodynamic design indicators in actual production. Please refer to Figure 6 , the included angle γ between the warped surface 304 and the back pressure surface satisfies 140° ≤ γ ≤ 151°.

[0051] On the basis of the above embodiments, the structure of the hub 20 is defined. A shaft sleeve 201 for key connection with the motor shaft is provided at the center of the hub 20. A plurality of twisted spokes 203 are evenly arranged along the circumferential direction of the shaft sleeve 201. A connection hole 204 for connecting with the blade 30 is provided at the outer edge of the spoke 203;

[0052] A reinforcing ring 202 is provided between the shaft sleeve 201 and the spoke 203 to enhance the structural strength of the shaft sleeve 201.

[0053] Please refer to Figure 7 , the shaft sleeve 201 is provided with a through shaft hole. The inner diameter of the shaft sleeve 201 is determined according to the diameter of the motor shaft. The outer diameter of the shaft sleeve 201 and the thickness of the reinforcing ring 202 are determined according to the design structural strength, especially the torsional strength check calculation;

[0054] The spokes 203 are evenly distributed along the circumferential direction of the sleeve 201. The angle between the cross-section of the spoke 203 and the sleeve 201 is the torsion angle β of the spoke 203, which is determined according to the blade installation angle of the blade 30, and the two need to be consistent.

[0055] A number of connection holes 204 are provided on the outer edge of the spoke 203. The number and size of the connection holes 204 are determined according to the number and size of the fasteners, and the number and size of the fasteners are determined according to the designed connection strength between the hub 20 and the blade 30;

[0056] The distribution of the connection holes 204, such as the center distance between two adjacent connection holes 204, etc., is determined according to the root shape of the blade 30 in actual production, so as to avoid excessive local stress on the blade 30.

[0057] Preferably, in order to enhance the torsional strength of the spoke 203, a continuous reinforcing rib 205 can be provided in the connection hole 204 of the spoke 203. The shape of the reinforcing rib 205 is similar to the shape of the outer edge of the spoke 203. It should be noted that the similarity here means the similarity of the geometric shapes of the two.

[0058] The length and width of the reinforcing rib 205 are determined by checking and calculating according to the design strength requirements. The distance between the reinforcing rib 205 and the connection hole 204 is determined according to the type and size of the fasteners, etc., so as to reserve enough installation space.

[0059] In this specification, each embodiment is described in a progressive manner. The key point of each embodiment is to illustrate the differences from other embodiments. The same or similar parts among the embodiments can be referred to each other.

[0060] The above has introduced the internal rotor axial flow fan provided by the present utility model in detail. Specific examples are used herein to elaborate on the principle and implementation manner of the present utility model. The description of the above embodiments is only used to help understand the method and its core idea of the present utility model. It should be pointed out that for those of ordinary skill in the art in this technical field, without departing from the principle of the present utility model, several improvements and modifications can be made to the present utility model, and these improvements and modifications also fall within the protection scope of the claims of the present utility model.

Claims

1. An inner rotor axial flow fan, characterized in that: include: A motor (10), a wheel hub (20) and a plurality of blades (30), wherein the wheel hub (20) is sleeved outside a motor shaft of the motor (10), the wheel hub (20) is key-connected to the motor shaft, and the blade roots of the blades (30) are connected to the outer edges of the wheel hub (20) via fasteners; The trailing edge of the blade (30) is provided with a continuous sawtooth-shaped notch (303), and the sawtooth-shaped notch (303) is used to stratify the airflow and suppress the outflow vortex, so as to improve the efficiency of the fan and reduce the noise.

2. The inner rotor axial flow fan according to claim 1, characterized in that: The leading edge of the blade (30) is provided with a blunt rounded corner (302), and the radius of the blunt rounded corner (302) is Rt=0.6-0.9T, wherein T is the blade body thickness of the blade (30).

3. The inner rotor axial flow fan according to claim 1, characterized in that: The radial distance between any two adjacent inner vertices of the sawtooth-shaped notches is the same, and the radial distance between any two adjacent outer vertices of the sawtooth-shaped notches is the same.

4. The inner rotor axial flow fan according to claim 1, characterized in that: The outer edge of the blade (30) is warped toward the back pressure surface, and the included angle γ between the warped surface (304) and the back pressure surface gradually decreases from the trailing edge to the leading edge.

5. The inner rotor axial flow fan according to claim 4, characterized in that: An included angle γ between the warping surface (304) and the back pressure surface satisfies 140°≤γ≤151°.

6. The inner rotor axial flow fan according to any one of claims 1 to 5, characterized in that: The blade root of the blade (30) is provided with a mounting hole (301), the outer edge of the hub (20) is provided with a connecting hole (204), and the blade (30) and the hub (20) are connected by riveting.

7. The inner rotor axial flow fan according to claim 6, characterized in that: A shaft sleeve (201) for connecting to the motor shaft key is provided at the center of the hub (20), a plurality of twisted spokes (203) are evenly arranged on the shaft sleeve (201) along the circumferential direction, and the outer edge of the spoke (203) is provided with the connecting hole (204) for connecting to the blade (30); A reinforcing ring (202) is provided between the shaft sleeve (201) and the spoke (203) to enhance the structural strength of the shaft sleeve (201).

8. The inner rotor axial flow fan according to claim 7, characterized in that: The spoke (203) is provided with a circle of continuous reinforcing ribs (205) in the connecting hole (204), and the shape of the reinforcing ribs (205) is similar to the shape of the outer edge of the spoke (203).

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