An integrated fan structure

Abstract

This invention relates to the field of fan manufacturing technology, specifically disclosing an integrated fan structure. This structure includes a rotor and blade assembly. The blade assembly is integrally formed from a bushing and multiple blades through a stamping process. Each blade includes a bent portion and a blade section. The bent portion is connected to the bushing via a transition connection structure to eliminate stress concentration points. The blade section forms a 20-30° torsion angle through the bent portion. A copper bushing is embedded in the inner wall of the rotor. The copper bushing and the rotor, as well as the rotor and the bushing, are assembled and connected by interference fits. This invention reduces the assembly time of the fan structure by more than 80% and the dynamic balance defect rate by more than 90% through a weld-free process, making it suitable for high-load scenarios such as transformer cooling and industrial ventilation.

Description

Technical Field

[0001] This invention relates to the field of fan manufacturing technology, and in particular to an integrated fan structure in which the blades and bushing are integrally formed by stamping process. Background Technology

[0002] Traditional fan structures consist of a bushing, a shaft, and multiple individual blades. The blades are typically fixed to the outer circumference of the rotor by welding or bolting. This type of structure requires precise control of the blade installation angle and position; otherwise, aerodynamic imbalance will occur. For example, transformer cooling fans require a blade clearance error of ≤0.1mm; otherwise, abnormal vibration will occur.

[0003] In the existing technology, blade fixing mainly relies on two methods: one is welding process, as described in CN103174675A, in which blades need to be welded to the rotor one by one, and after welding, multiple processes such as puttying, milling blade shanks, and turning axle sleeves are required; the other is split assembly, such as bladeless fan assembly (WO2013174037A1) which uses snap-fit ​​connection between the air ring and the body, but the blades still need to be installed separately to the motor rotor.

[0004] The existing technologies mentioned above have the following main defects: 1. Complex process: Welding requires positioning fixtures, which is time-consuming and labor-intensive, and the defect rate is relatively high (mainly due to dynamic imbalance caused by welding deformation); 2. Insufficient strength: Welding points are prone to stress cracks, especially in high-temperature environments (such as transformer cooling fans), which increases the risk of blade breakage; 3. Poor fit accuracy: There is a micro gap between the split structure and the rotor, which causes friction noise during operation. Summary of the Invention

[0005] The present invention aims to address the above-mentioned deficiencies by providing a weld-free, high-precision integrated fan structure, which solves the problems of positioning and strength through the integrated design of the blade assembly.

[0006] To achieve the above objectives, the present invention adopts the following technical solution:

[0007] An integrated fan structure includes a rotor and a blade assembly. The blade assembly includes an integrally formed bushing and a plurality of blades. The bushing and the rotor are assembled and connected by a first interference fit structure.

[0008] Furthermore, the inner wall of the rotor is nested with a copper bushing, and the copper bushing is assembled and connected to the bushing through a second interference fit structure.

[0009] Furthermore, the interference of the second interference fit structure is 0.02-0.05 mm.

[0010] Furthermore, the blade assembly is integrally formed by die casting, and the thickness of the blade decreases from the root to the tip.

[0011] Furthermore, the thickness of the bushing is 2.5-5mm.

[0012] Furthermore, the interference of the first interference fit structure is 0.03-0.06 mm.

[0013] Furthermore, the blade includes a bent portion and a blade portion, the blade portion having a twist angle of 20-30°, and a transition connection structure is provided between the bent portion and the bushing.

[0014] Furthermore, the dynamic balance of the blade assembly is less than 0.5 g·mm.

[0015] Furthermore, the surface of the blade is covered with a 5-15 micrometer thick nano-alumina wear-resistant coating.

[0016] Furthermore, the end of the copper bushing is provided with an annular anti-detachment flange, and the rotor end face is provided with a groove that engages with the anti-detachment flange.

[0017] Compared to traditional split-assembly fan structures, the advantages of this invention are:

[0018] 1. High-efficiency production: The weld-free design reduces assembly time by more than 80%, and the assembly process for a single piece can be reduced to less than 3 minutes;

[0019] 2. High reliability: One-piece molding eliminates stress concentration and significantly improves fatigue life;

[0020] 3. Precision control: The dynamic balance defect rate can be reduced to below 0.5%;

[0021] 4. Extended lifespan: The integrated structure improves fatigue resistance by 40% and has a wear life of over 20,000 hours. Attached Figure Description

[0022] Figures 1-2 According to some embodiments of the present invention, a structural schematic diagram of an integrated fan structure is shown;

[0023] Figure 3 An exploded view of an integrated fan structure is shown according to some embodiments of the present invention;

[0024] Figures 4-5 According to some embodiments of the present invention, a schematic diagram of the blade assembly is shown. Detailed Implementation

[0025] The technical features and advantages of this application will be described in more detail below with reference to the accompanying drawings, so that the advantages and features of this application can be more easily understood by those skilled in the art, thereby making a clearer and more explicit definition of the scope of protection of this invention.

[0026] It should be noted that in the description of this application, the terms "upper", "lower", "left", "right", "inner", "outer", etc., indicating directions or positional relationships are based on the directions or positional relationships shown in the drawings. This is only for the convenience of description and is not intended to indicate or imply that the device or element must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, it should not be construed as a limitation of the present invention.

[0027] The terms “first” and “second” are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly indicating the importance of the technical features shown.

[0028] Furthermore, it should be noted that, in the description of this application, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" 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 direct connection or an indirect connection through an intermediate medium; and they can refer to the internal communication between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0029] Please see Figures 1-5 This invention provides an integrated fan structure, including a rotor 10, an integrated blade assembly 20, and a copper bushing 30. The structure and process of each component are described in detail below with reference to the accompanying drawings.

[0030] Blade assembly 20: includes a bushing 21 and five radially distributed blades 22, which are integrally formed with the bushing 21 using a die-casting mold. The bushing 21 has a cylindrical structure with a wall thickness of 3.2 mm. Each blade 22 includes a bent portion 221 (radius of curvature R15 mm) and a blade portion 222 (twist angle 25°). The bent portion 221 is connected to the bushing 21 through a transition connection structure 23. The transition connection structure 23 is used to eliminate stress concentration points and improve structural strength. As an example, the transition connection structure 23 can be a transition ring structure with a width of 2-5 mm, and the five blades 22 are evenly distributed radially on the outer periphery of the transition ring. To reduce the overall weight of the blades 22, the blades 22 can be made with a gradually decreasing thickness structure, with the thickness gradually decreasing from the root to the tip. In this embodiment, the thickness of the blade 22 at the root is 3 mm, transitioning to 2.2 mm in the middle, and then gradually thinning to 1.5 mm at the tip, achieving a balance between strength and weight reduction while reducing weight. The blade assembly 20 can be integrally formed by die casting, using ADC12 aluminum alloy as the material. After die casting, it can undergo T6 heat treatment (535℃×2h solution treatment + 175℃×10h aging), followed by surface sandblasting to Ra3.2 and then coating with an 8-micron thick nano-alumina coating (adhesion ≥15MPa). In other embodiments, the blade assembly 20 can also be die-cast using magnesium alloy (e.g., AZ91D), which can further reduce weight and is suitable for applications with higher lightweight requirements, but will moderately increase costs. Alternatively, the blade assembly 20 can also be injection molded using composite materials, such as carbon fiber reinforced PA66.

[0031] To control the dynamic balance parameters of the fan structure, after the blade assembly 20 is die-cast, a three-coordinate correction method can be used:

[0032] 1. Coarse correction: Drill a φ2mm hole (maximum depth 3mm) to remove excess material;

[0033] 2. Precision correction: Laser micro-melting (removal amount 0.01-0.1g);

[0034] 3. The final dynamic balance amount is ≤0.35g·mm.

[0035] Rotor 10 and copper bushing 30: The copper bushing 30 can be made of C94300 copper alloy with a wall thickness of 2mm. The end can be stamped with an annular anti-slip flange with a height of 1.5mm. The inner surface can be opened with oil storage micro-grooves, with a depth of 0.1mm, a width of 0.3mm, and a spacing of 2mm, to improve lubrication durability. The anti-slip flange and the rotor groove can adopt a beveled guide design (guide angle α=15°) to ensure smooth assembly.

[0036] A first-stage interference fit structure is provided between the bushing 21 and the rotor 10, with an interference amount of 0.035mm; a second-stage interference fit structure is provided between the copper bushing 30 and the rotor 10, with an interference amount of 0.04mm. Multiple heat dissipation holes 11 can be opened along the axial direction on the rotor 10 to achieve ventilation and heat dissipation.

[0037] The copper bushing 30 and the rotor 10 can be joined using a cold-fitting process. Specifically, the copper bushing 30 is frozen in liquid nitrogen (-196℃×15min) and then pressed into the rotor 10, which is preheated to 150℃. The interference fit between the two is set to 0.04mm. The blade assembly 20 and the rotor 10 can be joined using a hot-fitting process, which is achieved by hydraulic expansion (pressure 80MPa). Both methods ensure connection strength while controlling the interference fit.

[0038] The integrated fan structure of this invention improves overall strength while reducing processing difficulty and shortening the production cycle. Its applications include, but are not limited to: heavy-duty applications (such as transformer oil cooling systems with air pressure ≥800Pa), precision applications (such as data center liquid cooling units with vibration ≤0.5mm / s), and special environments (such as mine ventilation equipment with dust concentration >200mg / m³). 3 Based on the applicant's actual testing, the performance improvement data of the integrated fan structure of this invention compared to the traditional welded fan structure is shown in the table below:

[0039] In the description of this specification, references to terms such as "some embodiments," "some examples," "exemplarily," "example," "preferred," or "further" indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0040] The above description is merely an embodiment of this application and does not limit the patent scope of this application. Any equivalent structural or procedural transformations made based on the content of this specification and drawings, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of this application.

Claims

1. An integrated fan structure, characterized by comprising: It includes a rotor (10) and a blade assembly (20), the blade assembly (20) including an integrally formed bushing (21) and a plurality of blades (22), the bushing (21) and the rotor (10) being assembled and connected by a first interference fit structure.

2. The integrated fan structure of claim 1, wherein: The inner wall of the rotor (10) is nested with a copper bushing (30), and the copper bushing (30) and the bushing (21) are assembled and connected by a second interference fit structure.

3. The one-piece fan structure of claim 2, wherein: The interference of the second interference fit structure is 0.02-0.05 mm.

4. The one-piece fan structure of claim 1, wherein: The blade assembly (20) is integrally formed by a stamping process, and the thickness of the blade (22) decreases from the root to the tip.

5. The one-piece fan structure of claim 1, wherein: The thickness of the bushing (21) is 2.5-5mm.

6. The one-piece fan structure of claim 1, wherein: The interference of the first interference fit structure is 0.03-0.06 mm.

7. The integrated fan structure of claim 1, wherein: The blade (22) includes a bent portion (221) and a blade portion (222). The twist angle of the blade portion (222) is 20-30°. A transition connection structure (23) is provided between the bent portion (221) and the bushing (21).

8. The integrated fan structure according to claim 1, characterized in that: The dynamic balance of the blade assembly (20) is less than 0.5 g·mm.

9. The integrated fan structure according to claim 1, characterized in that: The surface of the blade (22) is covered with a 5-15 micrometer thick nano-alumina wear-resistant coating.

10. The integrated fan structure according to claim 2, characterized in that: The end of the copper bushing (30) is provided with an annular anti-detachment flange, and the end face of the rotor (10) is provided with a groove that engages with the anti-detachment flange.

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