A wind channel structure for reducing wind loss of a handheld fan

Abstract

This utility model relates to a duct structure for reducing airflow loss in a handheld fan, comprising a duct housing, a motor protective cover, and fan blades. Several guide vanes are disposed between the duct housing and the motor protective cover. The fan blades are located on the side of the motor protective cover near the air inlet and are connected to the motor output shaft inside the protective cover. The guide vanes extend from the air inlet side of the motor protective cover to the middle position along an inclined direction, consistent with the airflow direction of the fan blades, and then extend along the duct axis from the middle position of the motor protective cover to the air outlet side. The duct structure of this utility model uses curved guide vanes, the front half of which is inclined, allowing the inclined airflow from the fan blades to enter the guiding area without obstruction, reducing energy loss caused by airflow impact. The rear half of the guide vanes extends along the duct axis, gradually guiding the initially inclined airflow to the axial direction, ensuring orderly and stable airflow and reducing airflow loss.

Description

Technical Field

[0001] This utility model relates to the field of handheld fans, specifically to a duct structure for handheld fans that reduces airflow loss. Background Technology

[0002] Handheld fans, as portable cooling devices, are widely used in daily life, outdoor activities, and office settings due to their small size, light weight, and ease of operation. The core function of a handheld fan is to use a motor to drive the fan blades to rotate, drawing air into the air duct and accelerating its expulsion, thereby generating a cooling airflow.

[0003] Traditional handheld fans have significant flaws in their duct structure design, leading to prominent airflow loss issues. Specifically, because the internal structure of traditional ducts fails to fully consider the tilting and rotating characteristics of the airflow generated by the fan blades, the airflow easily forms turbulent eddies and currents within the duct after being blown out from the fan blades. This causes a large amount of airflow to collide and rub against each other inside the duct, resulting in energy loss, affecting airflow efficiency, and preventing smooth airflow along the axial direction of the duct.

[0004] Most products on the market today rely on the tilting blades on the fan panel at the air outlet to guide airflow and improve the direction of airflow. However, the tilting blades only guide the airflow at the air outlet. They not only fail to fundamentally solve the problem of airflow loss in the air duct, but also exacerbate the airflow loss due to the additional obstruction.

[0005] The above problems are worth solving. Utility Model Content

[0006] To address the problem that existing handheld fans suffer from low airflow efficiency due to turbulent eddies and vortices caused by duct structure designs that do not match airflow characteristics, resulting in collisions and increased energy loss, this invention provides a duct structure for handheld fans that reduces airflow loss.

[0007] The technical solution of this utility model is as follows:

[0008] A duct structure for reducing airflow loss in a handheld fan includes a duct housing, a motor protective cover, and fan blades. The duct housing serves as the head housing of the handheld fan, with openings on both sides forming the air inlet and outlet of the duct, respectively. A plurality of air guide vanes are provided between the duct housing and the motor protective cover, and the motor protective cover is coaxially assembled in the duct housing through the plurality of air guide vanes. The fan blades are located on the side of the motor protective cover near the air inlet and are connected to the motor output shaft inside the protective cover. The air guide vanes are curved and extend from the air inlet side of the motor protective cover to the middle position along an inclined direction, with the inclined direction consistent with the airflow direction of the fan blades, and then extend from the middle position of the motor protective cover to the air outlet side along the duct axis.

[0009] As a preferred embodiment of this utility model, both the air duct housing and the motor protective cover are cylindrical.

[0010] As a preferred embodiment of this invention, the outer diameter of the fan blade shaft is larger than the outer diameter of the motor protective cover.

[0011] As a preferred embodiment of this utility model, the fan blades are inclinedly arranged on the circumferential surface of the fan shaft, and the angle between the blade surface normal and the inclined portion of the air guide is less than 5°.

[0012] As a preferred embodiment of this invention, the number of fan blades is equal to the number of air guide vanes.

[0013] As a preferred technical solution of this utility model, the motor protective cover has a protective shaft protruding on the side near the fan blade, and the motor output shaft passes through the protective shaft and is connected to the axis of the fan blade.

[0014] Furthermore, the motor protective cover is provided with a wiring window on the side near the fan blade, and the wiring window is located below the protective shaft.

[0015] As a preferred technical solution of this utility model, the air outlet of the air duct shell is provided with an air gathering hood. The air gathering hood is annular, and its inner diameter gradually decreases from the air inlet side to the air outlet side, forming a gradually narrowing structure.

[0016] As a preferred technical solution of this utility model, the air duct shell, the plurality of air guide vanes and the motor protective cover are integrally formed.

[0017] As a preferred technical solution of this utility model, the bottom of the air duct housing is integrally formed with the front housing of the handheld fan handle.

[0018] The advantages of this utility model based on the above solution are as follows:

[0019] The curved guide vane of this invention, located between the motor protective cover and the duct housing, has a front half that is inclined in the same direction as the fan blades, allowing the inclined airflow from the fan blades to enter the guide area without obstruction and with low loss. This achieves efficient guidance from the source of the airflow, reducing energy loss caused by airflow impact. The rear half of the guide vane extends along the duct axis, gradually guiding the initially inclined airflow to the axial direction, ensuring that the airflow remains orderly within the duct and is blown out from the outlet smoothly, significantly reducing airflow loss caused by airflow turbulence.

[0020] Moreover, the motor protective cover and the air guide plate are coaxially assembled to ensure the symmetry of the air duct structure, reduce airflow deviation and eddies caused by structural eccentricity, and further improve airflow delivery efficiency.

[0021] In addition, the air guide plate also serves as a support for the motor protective cover, eliminating the need for an additional independent motor protective cover support component. This saves space and material costs, simplifies the assembly process of the air duct structure, and improves the space utilization of the handheld fan head housing through an integrated structural design. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the air duct structure of this utility model;

[0023] Figure 2 This is a schematic diagram showing the tilt angle of the fan blades and the air guide vanes in this utility model;

[0024] Figure 3 This is a schematic diagram of a handheld fan.

[0025] Figure 4 This is an exploded view of the handheld fan head.

[0026] In the diagram,

[0027] 1. Duct housing; 11. Air inlet; 12. Air outlet;

[0028] 2. Motor protective cover; 21. Protective shaft; 22. Wiring window;

[0029] 3. Fan blades; 4. Air guide vanes; 5. Handle; 6. Air concentrator cover. Detailed Implementation

[0030] To better understand the purpose, technical solution, and technical effects of this utility model, the following description, in conjunction with the accompanying drawings and embodiments, will provide further explanation. It should be noted that similar reference numerals and letters in the following drawings indicate similar items; therefore, once an item is defined in one drawing, it does not need further definition and explanation in subsequent drawings. It is also stated that the embodiments described below are only for explaining this utility model and are not intended to limit it.

[0031] It should be noted that when a component is referred to as "fixed to" or "set on" another component, it can be directly on the other component or there may be an intermediate component. When a component is referred to as "connected to" another component, it can be directly connected to the other component or there may be an intermediate component.

[0032] The indicated orientation or positional relationship is based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship commonly used when the product is in use, or the orientation or positional relationship commonly understood by those skilled in the art, and is only for the convenience of describing this application and simplifying the description, and is not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation on this application. The term "several" means two or more, unless otherwise expressly and specifically defined.

[0033] like Figures 1 to 4 As shown, a duct structure for reducing airflow loss in a handheld fan includes a duct housing 1, a motor protective cover 2, and fan blades 3. The duct housing 1 serves as the head housing of the handheld fan, with openings on both sides forming an air inlet 11 and an air outlet 12, respectively. A perforated mesh protective cover (not shown) is provided on one side of the air inlet 11 of the duct housing 1 to improve product safety. The head housing (i.e., the duct housing 1), along with components such as the air guide vanes 4 and the motor protective cover 2, can be manufactured using an integrated molding process, reducing assembly steps. Several air guide vanes 4 are provided between the duct housing 1 and the motor protective cover 2, and the motor protective cover 2 is coaxially assembled into the duct housing 1 through these air guide vanes 4, ensuring the symmetry of the duct structure, reducing airflow deflection and eddies caused by structural eccentricity, and further improving airflow delivery efficiency.

[0034] The fan blade 3 is located on the side of the motor protective cover 2 near the air inlet 11 and is connected to the motor output shaft inside the protective cover; the motor is installed inside the motor protective cover 2 and is fixedly connected to the shaft of the fan blade 3 through the motor output shaft to form a stable power transmission structure.

[0035] The air guide vane 4 is curved. It extends from the air inlet 11 of the motor protective cover 2 along an inclined direction to the middle position, with the inclined direction consistent with the airflow direction of the fan blades 3. Then, it extends along the duct axis from the middle position of the motor protective cover 2 to the air outlet 12. Because the fan blades 3 are inclined on the circumference of the fan shaft, the fan blades 3 generate an inclined airflow when rotating. The inclined direction of the first half of the air guide vane 4 is parallel to this airflow direction. Figure 1 The arrow indicating the airflow means that after the airflow is blown out from the fan blade 3, it can directly enter the air guide area along the inclined surface of the air guide 4, that is, enter the unobstructed air guide channel, avoiding impact loss caused by sudden change in direction.

[0036] like Figure 2 As shown, specifically, the blades of fan blade 3 are tilted, with the angle α between the blade surface normal and the horizontal axis being 40° to 45°. The angle b between the tilted section of guide vane 4 and the horizontal axis is 35° to 40°, and the angle between the blade surface normal n and the tilted section of guide vane 4 is less than 5°, meaning the maximum difference between angle α and angle b is less than 5°. In this configuration, the airflow generated by fan blade 3 can enter the guide vane area with minimal impact angle, entering almost along the surface of guide vane 4, thus minimizing frictional loss.

[0037] The rear half of the air guide vane 4 extends along the axial direction of the air duct, gradually "correcting" the initially tilted airflow to the axial direction of the air duct; at the same time, through the gradual guiding structure, the airflow velocity field is homogenized, reducing the velocity difference and turbulence inside the airflow, and achieving smooth axial flow.

[0038] In addition, the air guide plate 4 also serves as a support for the motor protective cover 2, eliminating the need for an additional independent support for the motor protective cover 2. This saves space and material costs, simplifies the assembly process of the air duct structure, and improves the space utilization of the handheld fan head housing through the integrated structural design.

[0039] In this embodiment, the outer diameter of the fan blade 3 is larger than the outer diameter of the motor protective cover 2, so that the root of the fan blade 3 extends beyond the outer periphery of the motor protective cover 2. The airflow generated when the blade rotates can be directly blown towards the annular ventilation area on the outer periphery of the motor protective cover 2, avoiding the airflow being blocked by the motor protective cover 2.

[0040] In an optional embodiment, the number of fan blades 3 is equal to the number of air guide vanes 4. Each airflow blown out by the fan blades 3 enters a corresponding air guide vane area, forming a one-to-one airflow path, avoiding mutual interference of airflows and further reducing losses.

[0041] like Figure 4As shown, in one optional embodiment, a protective shaft 21 protrudes from the side of the motor protective cover 2 that connects to the fan blade 3. The motor output shaft passes through the protective shaft 21 and connects to the axis of the fan blade 3. The protective shaft 21 provides guidance and support for the motor output shaft, preventing it from wobbling during high-speed rotation. Simultaneously, this side of the motor protective cover 2 also has a wiring window 22 located below the protective shaft 21, for the neat routing of motor cables, ensuring orderly wiring, preventing interference with the rotating parts of the fan blade 3, guaranteeing smooth airflow within the duct, and facilitating circuit connection and maintenance.

[0042] In a preferred embodiment, an air-concentrating shroud 6 is provided on the inner periphery of the air outlet 12 of the air duct housing 1. The air-concentrating shroud 6 is annular, and its inner diameter gradually decreases from the air inlet 11 side to the air outlet 12 side, forming a gradually narrowing structure, i.e., a flow channel with a contracting cross-section. When the airflow passes through the contracting cross-section, the flow velocity increases, and the airflow converges, reducing the air outlet diffusion angle and reducing the radial diffusion energy loss when the airflow is ejected from the air outlet 12, thereby improving the cooling effect of the blowing air.

[0043] In this embodiment, both the duct housing 1 and the motor protective cover 2 are cylindrical. The cylindrical structure has smooth sidewalls and a regular cross-sectional shape, resulting in a more uniform circumferential velocity distribution when airflow passes through the duct, reducing airflow separation and turbulence caused by abrupt changes in cross-section (such as the sharp corners of a square structure). Within the circumferential space between the cylindrical duct housing 1 and the motor protective cover 2, the guide vanes 4 are fixed at equal angles along the circumference, such as 6 vanes 4 spaced at 60° intervals, ensuring balanced force on each vane 4 and avoiding stress concentration due to uneven distribution.

[0044] In this embodiment, the air duct housing 1, air guide plate 4, motor protective cover 2 and other components can be integrally molded to achieve no assembly gaps between components and prevent airflow leakage from gaps; at the same time, the overall rigidity of the product is improved and its drop resistance is enhanced, making it suitable for portable scenarios of handheld devices.

[0045] In this embodiment, the bottom of the air duct housing 1 is integrally formed with the front housing of the handheld fan handle 5. The air duct housing 1 (head) and the front housing of the handle are directly formed as a single part, which further simplifies the assembly steps and also helps to eliminate the splicing gap between the head and the handle in the traditional design, thus improving the drop resistance.

[0046] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0047] The above embodiments only illustrate several implementation methods of this utility model, and their descriptions are relatively specific and detailed, but they should not be construed as limiting the scope of the utility model patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this utility model, and these all fall within the protection scope of this utility model. Therefore, the protection scope of this utility model patent should be determined by the appended claims.

Claims

1. A duct structure for reducing airflow loss in a handheld fan, characterized in that, The device includes a duct housing, a motor protective cover, and fan blades. The duct housing serves as the head housing of the handheld fan, with openings on both sides forming the air inlet and outlet of the duct, respectively. Several air guide vanes are provided between the duct housing and the motor protective cover, and the motor protective cover is coaxially assembled in the duct housing through several air guide vanes. The fan blades are located on the side of the motor protective cover near the air inlet and are connected to the motor output shaft inside the protective cover. The air guide vane is curved. The air guide vane first extends from the air inlet side of the motor protective cover to the middle position along an inclined direction, and the inclined direction is consistent with the wind direction of the fan blade. Then it extends from the middle position of the motor protective cover to the air outlet side along the duct axis.

2. The air duct structure for reducing airflow loss in a handheld fan according to claim 1, characterized in that, Both the air duct housing and the motor protective cover are cylindrical.

3. The air duct structure for reducing airflow loss in a handheld fan according to claim 1, characterized in that, The outer diameter of the fan blade shaft is larger than the outer diameter of the motor protective cover.

4. The air duct structure for reducing airflow loss in a handheld fan according to claim 1, characterized in that, The fan blades are inclined on the circumference of the fan shaft, and the angle between the blade surface normal and the inclined part of the air guide is less than 5°.

5. The air duct structure for reducing airflow loss in a handheld fan according to claim 1, characterized in that, The number of fan blades is equal to the number of air guide vanes.

6. The air duct structure for reducing airflow loss in a handheld fan according to claim 1, characterized in that, The motor protective cover has a protective shaft protruding from the side near the fan blade, and the motor output shaft passes through the protective shaft and connects to the axis of the fan blade.

7. A duct structure for reducing airflow loss in a handheld fan according to claim 6, characterized in that, The motor protective cover also has a wiring window on the side near the fan blade, and the wiring window is located below the protective shaft.

8. The air duct structure for reducing airflow loss in a handheld fan according to claim 1, characterized in that, The air outlet of the air duct shell is provided with an air gathering hood. The air gathering hood is annular, and its inner diameter gradually decreases from the air inlet side to the air outlet side, forming a gradually narrowing structure.

9. A duct structure for reducing airflow loss in a handheld fan according to claim 1, characterized in that, The air duct housing, the several air guide vanes, and the motor protective cover are integrally formed.

10. A duct structure for reducing airflow loss in a handheld fan according to claim 1, characterized in that, The bottom of the air duct housing is integrally formed with the front housing of the handheld fan handle.

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