Axial-flow fan blade with frustum-shaped hub
By using a frustum-shaped hub and reinforcing ribs, the airflow disturbance and flow path continuity of the outdoor unit are improved, resolving the contradiction between aerodynamic and structural performance of traditional outdoor units, and achieving more efficient air volume output and reduced noise.
Patent Information
- Application Number
- CN202520599759.X
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2025-03-31
- Publication Date
- 2026-02-06
- Estimated Expiration
- 2035-03-31
AI Technical Summary
Traditional air conditioner outdoor units with axial fan blades suffer from severe airflow disturbance, lack of flow path continuity, and contradictions between aerodynamic and structural performance, resulting in airflow loss and increased noise.
The wheel adopts a frustum-shaped hub structure, improves airflow disturbance through a gradually changing outer diameter design, maintains flow path continuity by integrating the blades with the hub, and sets reinforcing ribs and protruding columns inside the hub to improve structural rigidity and torsional resistance.
It significantly reduces energy loss caused by airflow disturbance, increases air volume output, reduces flow noise, increases air delivery head, and enhances mechanical strength while maintaining quiet performance.
Smart Images
Figure CN223881427U_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The utility model relates to air conditioner outdoor unit heat radiation component technical field especially relates to a conical hub axial flow fan blade. BACKGROUND
[0002] The axial flow fan blade is the core heat radiation component of the air conditioner outdoor unit, and its aerodynamic performance directly affects the overall machine efficiency and noise level. The traditional design scheme adopts a cylindrical hub to cooperate with an equal cross-section blade structure to generate axial airflow through motor driving to complete heat exchange. The typical structure includes a hub base body, a circumferentially uniformly distributed blade assembly and an end reinforcing ring, wherein the hub diameter is usually kept constant, and the blade root is connected to the outer surface of the hub at a fixed installation angle.
[0003] However, the prior art has multiple technical bottlenecks in the implementation process, which seriously restricts the performance improvement of the air conditioner outdoor unit.
[0004] Firstly, the incoming airflow disturbance is serious. The equal diameter structure of the traditional cylindrical hub causes the airflow to suddenly expand in the hub leading edge area. When the air medium enters the hub area, the sudden expansion of the flow cross section causes the boundary layer to separate, forming a local vortex area. This not only causes a loss of 12%-15% of the incoming air volume, but also induces 3-5dB(A) of medium-low frequency aerodynamic noise, which seriously affects the quiet performance of the air conditioner outdoor unit. Secondly, the flow path continuity is missing. The existing blade and hub junction has a geometric mutation, and the airflow needs to experience two flow direction deflections: the first is the diffusion loss caused by the sudden expansion of the cross section at the hub leading edge, and the second is the energy loss caused by the discontinuity of the curvature at the blade root.
[0005] In view of the above problems, the prior art needs to be improved. SUMMARY
[0006] In order to solve the above problems, the purpose of the utility model is to provide a conical hub axial flow fan blade, which has the advantages of improving the incoming airflow disturbance, improving the flow path continuity and solving the contradiction between aerodynamic and structural performance.
[0007] In order to achieve the above purpose, the utility model adopts the following technical scheme:
[0008] The application provides a conical hub axial flow fan blade, and the technical scheme is as follows: a hub and a plurality of blades are included; the hub is a conical hub, the outer diameter of which gradually increases from the air inlet side to the air outlet side of the axial flow fan blade, a motor shaft hole is arranged at the center of the end face of the air inlet side of the conical hub; the inner edges of the plurality of blades are integrally connected to the outer side wall surface of the conical hub and are uniformly and spacedly arranged along the circumference of the hub.
[0009] Further, the application also provides that the large end diameter of the conical hub is The small end diameter is And satisfy the relationship: (D-d) / D = 0.2~0.45.
[0010] Further, the application also provides that the outer wall shape of the frustum-shaped hub is one of linear, circular arc, wavy or tooth line.
[0011] Further, the application also provides that the small end face and the conical side face of the frustum-shaped hub are smooth surfaces.
[0012] Further, the application also provides that the large end of the frustum-shaped hub is recessed inward to form a hub cavity, and a plurality of reinforcing ribs are arranged in the hub cavity.
[0013] Further, the application also provides that a convex column is arranged at the center of the hub cavity, the motor shaft hole extends from the center of the air inlet side end face of the frustum-shaped hub to the inside of the convex column, and the plurality of reinforcing ribs are distributed radially around the convex column, and the outer ends of the reinforcing ribs are connected to the inner wall of the hub cavity.
[0014] As can be seen from the above, the application provides a kind of frustum-shaped hub axial flow fan blade, comprising a frustum-shaped hub and a plurality of blades, the diameter of the frustum-shaped hub gradually increases from air inlet side to air outlet side, and the inner edge of the plurality of blades is integrally connected to the outer wall surface of the frustum-shaped hub. This design improves the disturbance of the incoming air flow through the gradual change structure of the frustum-shaped hub, improves the continuity of the flow path, and solves the contradiction between aerodynamics and structural performance, with the advantages of improving the disturbance of the incoming air flow, improving the continuity of the flow path, and solving the contradiction between aerodynamics and structural performance. BRIEF DESCRIPTION OF DRAWINGS
[0015] Figure 1 A perspective view of a frustum-shaped hub axial flow fan blade is provided.
[0016] Figure 2 An end view of a frustum-shaped hub axial flow fan blade is provided.
[0017] Figure 3 A bottom view of a frustum-shaped hub axial flow fan blade is provided.
[0018] Figure 4 A Figure 3 A-A sectional view. DETAILED DESCRIPTION
[0019] The embodiments of the application are described in detail below, and examples of the embodiments are shown in the drawings, wherein the same or similar reference signs represent the same or similar elements or elements with the same or similar functions throughout. The embodiments described below by reference to the drawings are exemplary and are intended to explain the application, and cannot be understood as a limitation of the application.
[0020] In the description of the utility model, it is understood that the orientation or positional relationship indicated by the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "clockwise", "counterclockwise" and the like is the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, which is only for the convenience of describing the utility model and simplifying the description, and does not indicate or imply that the device or element indicated must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the utility model.
[0021] In addition, the terms "first" and "second" are only for the purpose of description, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined with "first" and "second" can explicitly or implicitly include one or more of the features. In the description of the utility model, unless otherwise specified, the meaning of "a plurality of" is two or more, unless otherwise explicitly limited.
[0022] In the utility model, unless otherwise explicitly specified and limited, the terms "mounting", "connection", "connection", "fixing" and the like should be understood in a broad sense, for example, it can be fixedly connected, or it can be detachably connected, or integrally connected; it can be mechanically connected, or it can be electrically connected; it can be directly connected, or it can be indirectly connected through an intermediate medium, or it can be the communication between two elements. For ordinary skilled in the art, the specific meaning of the above terms in the utility model can be understood according to the specific circumstances.
[0023] In the utility model, unless otherwise explicitly specified and limited, the "upper" or "lower" of the first feature to the second feature can include the direct contact of the first and second features, or the indirect contact of the first and second features through another feature between them. Moreover, the "upper", "upper" and "upper" of the first feature to the second feature include the vertical and inclined upward of the first feature above the second feature, or only indicate that the horizontal height of the first feature is higher than that of the second feature. The "below", "below" and "below" of the first feature to the second feature include the vertical and inclined downward of the first feature below the second feature, or only indicate that the horizontal height of the first feature is less than that of the second feature.
[0024] As Figures 1-4As shown, the embodiment proposes a taper hub axial flow fan blade, which comprises a hub 1 and a plurality of blades 2. The hub 1 is a taper hub, which gradually increases in outer diameter from the air inlet side to the air outlet side of the axial flow fan blade. The taper hub 1 is provided with a motor shaft hole 3 at the center of the end face of the air inlet side. The inner edges of the plurality of blades 2 are integrally connected to the outer side wall surface of the taper hub 1 and are uniformly and spacedly arranged along the circumference of the hub. The technical scheme realizes smooth transition of airflow through the taper hub 1 structure, wherein the gradually expanding shape avoids the cross-section mutation problem of the traditional cylindrical hub. When the airflow flows from the air inlet side to the air outlet side, a continuous accelerated flow field is formed along the surface of the hub 1, thereby effectively suppressing the boundary layer separation phenomenon. The integrated connection of the blades 2 and the hub 1 eliminates the geometric discontinuity and maintains the continuity of the flow path. The air inlet area of this scheme is increased, the air volume is improved, the flow velocity is accelerated, the air pressure is improved, and the air supply lift is improved. Compared with the prior art, the design significantly reduces the energy loss caused by airflow disturbance, and the air inlet loss can be reduced to below 5%. At the same time, the flow noise is reduced by about 4dB(A), and the main noise frequency band shifts to the high frequency region, which is more easily eliminated through acoustic treatment. In terms of structure, the gradually expanding hub 1 not only provides sufficient blade 2 support stiffness, but also avoids the air inlet blockage caused by the excessively large diameter, so that the blade 2 root stress concentration coefficient is controlled to be below 2.0. This scheme can improve the air volume output by 8-12% while maintaining low noise, and is particularly suitable for air conditioning outdoor unit equipment with high quietness requirements.
[0025] Further, the application also proposes that the large end 4 diameter of the taper hub 1 is the small end 5 diameter is and satisfies the relationship (D-d) / D=0.2-0.45. Specifically, the difference ratio of the large end 4 diameter D and the small end 5 diameter d is accurately limited to ensure that the taper change rate of the hub 1 is in the optimal range. As a preferred embodiment, D can be 200mm, and d can be 110mm-160mm. In another embodiment, when D is 180mm, d needs to be controlled within the range of 108mm-144mm. Thus, the technical scheme establishes a mathematical relationship between the large end 4 diameter and the small end 5 diameter, so that the hub 1 forms a transition structure with a specific taper. When the airflow flows along the taper surface, the flow cross-section presents a gradual change, avoiding the flow mutation caused by the traditional cylindrical hub. Specifically, the ratio range of 0.2-0.45 is verified by fluid mechanics simulation: below the lower limit, the airflow acceleration effect is insufficient and cannot effectively suppress the boundary layer separation; exceeding the upper limit will cause the structure stress concentration coefficient of the hub 1 to exceed 1.8 times the safety threshold. Experimental data show that the taper hub 1 with this ratio range can reduce the vortex area of the air inlet side by 62%, while keeping the equivalent stress at the root connection of the blade 2 below 45% of the material yield strength. This design realizes the synergistic optimization of aerodynamic performance and mechanical strength while maintaining the basic structure of the hub 1.
[0026] The outer diameter increasing design of the frustum-shaped hub 1 can be realized in various ways. Specifically, the outer wall shape of the frustum-shaped hub 1 is one of straight line, circular arc, wave shape or tooth line. The straight line outer wall realizes smooth airflow transition through simple geometric construction, and can be formed by rotating a single straight line generatrix. The circular arc outer wall is preferably a composite circular arc with a curvature radius R = (0.3-0.5)D. The wave-shaped outer wall is composed of a periodic wave with an amplitude A ≤ 0.05D. The tooth line-shaped outer wall contains triangular grooves with a depth h = 1-3mm. Thus, through the differentiated design of the four outer wall shapes, the airflow flow characteristics are improved in a targeted manner. The straight line configuration maintains the development of the laminar boundary layer, improving the uniformity of the flow velocity distribution in the hub area by more than 18%; the circular arc configuration controls the airflow deflection angle to within 8°, effectively suppressing flow separation; the wave-shaped configuration increases the turbulence intensity to 1.8 times through periodic disturbance, strengthening the convective heat transfer of the heat sink surface; the tooth line-shaped configuration reduces the broadband noise by 2-3dB by destroying the boundary layer through microstructure. These shapes all form a curvature-continuous flow channel with the inner edge of the blade 2, eliminating the flow discontinuity problem caused by traditional cylindrical hubs. Actual measurements show that the total pressure loss on the inlet side is reduced by 21%-34%.
[0027] In a further preferred embodiment, the small end face 7 and the tapered side surface 8 of the frustum-shaped hub 1 are both smooth surfaces. By setting the key contact surfaces of the frustum-shaped hub 1 as smooth surfaces, the frictional resistance of the airflow at the leading edge of the hub 1 can be reduced by 23%-28%. The overall smooth treatment of the tapered side surface 8 keeps the Reynolds number of the airflow below the critical value, reduces the boundary layer thickness by more than 40%, and effectively suppresses the flow separation phenomenon. Experimental data show that this design reduces the aerodynamic loss coefficient of the hub area from 0.15 to 0.09, and reduces the turbulence intensity at the root of the blade 2 by 62%. Compared with the traditional hub surface with machining marks, the smooth surface design allows the airflow to transition more smoothly to the working area of the blade 2, increasing the air volume of the entire machine by 5.3% while reducing the aerodynamic noise by 2.8dB(A). This technical solution improves the aerodynamic performance of the axial flow fan by precisely controlling the surface quality parameters of the hub 1 without significantly increasing the manufacturing cost.
[0028] In addition, as Figure 3 and 4As shown, the large end 4 of the conical hub 1 is recessed inward to form a hub cavity 9, and a plurality of reinforcing ribs 10 are arranged in the hub cavity 9. The recessed depth of the hub cavity 9 can be controlled within the range of 15%-30% of the diameter of the large end 4 of the hub 1, and the recessed profile can adopt a circular arc transition or a stepped transition. The arrangement of the reinforcing ribs 10 includes but is not limited to radial radiation distribution, annular array distribution or grid interlaced distribution, and the cross-sectional shape of the ribs can adopt a triangle, a trapezoid or an I-shaped section. The technical scheme forms the hub cavity 9 by recessing the large end 4, which not only reduces the weight but also increases the cross-sectional moment of inertia, so that the bending stiffness of the hub 1 is increased by about 35%-50%. The internal reinforcing rib 10 network disperses and transmits the concentrated stress to the whole hub 1, and the actual measurement shows that the maximum deformation can be reduced by more than 42%. Specifically, the recessed structure forms a smooth diffusion flow field in the transition area of the hub 1, avoiding the vortex loss caused by the diameter mutation in the traditional scheme; and the internal reinforcing rib 10 system increases the critical speed of the hub 1 by about 25% on the premise of ensuring the integrity of the aerodynamic shape, effectively solving the structural instability problem of the large-diameter hub. Compared with the prior art, the design realizes an increase of 1.8-2.3 times in the stiffness-to-weight ratio under the same material consumption, and does not increase the airflow resistance coefficient.
[0029] Further, a convex column 11 is arranged at the center of the hub cavity 9, and the motor shaft hole 3 extends from the center of the air inlet side end face of the conical hub 1 to the inside of the convex column 11; a plurality of reinforcing ribs 10 are radially distributed around the convex column 11, and the outer ends of the reinforcing ribs 10 are connected to the inner wall of the hub cavity 9. The technical scheme forms a through-type support structure through the convex column 11, increasing the axial contact length of the motor shaft hole 3. The radially distributed reinforcing ribs 10 establish a multi-directional force transmission path between the convex column 11 and the inner wall of the hub cavity 9, so that the cavity load is uniformly dispersed, and the radial stiffness of the hub cavity 9 is increased by 40%-60%. Compared with the traditional hub structure without a convex column, the scheme increases the torsional stiffness of the hub cavity 9 by more than 35% under the same material consumption, while ensuring that the aerodynamic performance is not affected.
[0030] In the description of the present specification, the description of the terms "one embodiment", "some embodiments", "an example", "a specific example" or "some examples" and the like means that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present application. In the present specification, the illustrative description of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.
[0031] Although the embodiments of the utility model have been shown and described above, it can be understood that the above-mentioned embodiments are exemplary and cannot be understood as limiting the utility model, and the ordinary skilled in the art can change, modify, replace and transform the above-mentioned embodiments within the scope of the utility model without departing from the principles and purposes of the utility model.
Claims
1. A tapered hub axial flow impeller, characterized by, The hub (1) and a plurality of blades (2) are included. The hub (1) is a conical hub with an outer diameter gradually increasing from the air inlet side to the air outlet side of the axial flow fan blade, and a motor shaft hole (3) is arranged at the center of the air inlet side end face of the conical hub (1). The inner edges of the plurality of blades (2) are integrally connected to the outer side wall surface of the conical hub (1) and are uniformly and spacedly arranged along the circumference of the hub.
2. The tapered hub axial fan blade of claim 1 wherein, The large end (4) of the conical hub (1) has a diameter D, the small end (5) has a diameter d, and the relationship (D-d) / D=0.2-0.45 is satisfied.
3. The tapered hub axial fan blade according to claim 1 or 2, characterized in that The outer wall shape of the conical hub (1) is one of a straight line, a circular arc, a wave shape, or a tooth line.
4. The tapered hub axial fan blade of claim 1 wherein, The small end face (7) and the conical side face (8) of the conical hub (1) are both smooth surfaces.
5. The tapered hub axial fan blade of claim 1 wherein, The large end of the conical hub (1) is recessed inward to form a hub cavity (9), and a plurality of reinforcing ribs (10) are arranged in the hub cavity (9).
6. The tapered hub axial fan blade of claim 5 wherein, A convex column (11) is arranged at the center of the hub cavity (9), the motor shaft hole (3) extends from the center of the air inlet side end face of the conical hub (1) to the inside of the convex column (11), the plurality of reinforcing ribs (10) are radially distributed around the convex column (11), and the outer ends of the reinforcing ribs (10) are connected to the inner wall of the hub cavity (9).