Axial-flow cooling fan

Abstract

The present application provides an axial-flow cooling fan, which comprises a hub and a plurality of conical blades. The hub has a rotation axis. The conical blades are arranged around the hub and driven by the hub. The conical blades are layered with each other and coaxial to the rotation axis to form an air inlet and an air outlet. The profile of each conical blade is gradually expanded from the air inlet to the air outlet.

Description

Technical Field

[0001] This invention relates to a cooling fan, and more particularly to an axial cooling fan. Background Technology

[0002] Existing axial fans are widely used in computer mainframes for heat dissipation. However, the performance of personal computers and servers has developed rapidly in recent years. High-performance computer mainframes also generate a lot of waste heat. In order to avoid the accumulation of waste heat causing poor operation of the mainframe, how to make high-flow fans to achieve good heat dissipation is an important goal at present.

[0003] Current axial fan design trends largely focus on blade optimization and frame (or housing) adjustments. However, limited by propeller-like blade designs, they remain confined to the realm of high airflow and low static pressure. Furthermore, the blades can be considered as sweeping across the frame (or housing) at a fixed frequency. Consequently, the blades are prone to producing narrow-band noise at the impact point due to their wake flow striking the frame (or housing). Following the principle of wave superposition, this wake flow generates a large-amplitude, fixed-frequency blade passing tone, which increases with rotational speed.

[0004] Furthermore, in existing axial fans, when rotating, airflow flows along the surface of the fan blades. Due to viscosity, the airflow velocity on the blade surface gradually slows down, eventually causing the airflow to separate from the blade surface and form vortices. The generation of vortices reduces the airflow through the fan, resulting in poor heat dissipation, and the vortex phenomenon also causes noise problems. Summary of the Invention

[0005] This invention relates to an axial cooling fan that generates an airflow similar to that of an axial fan through stacked conical blades, while reducing the noise generated by an axial fan.

[0006] According to an embodiment of the present invention, an axial cooling fan includes a hub and a plurality of conical blades. The hub has a rotation axis. The conical blades are arranged around the hub and driven by the hub. The conical blades are stacked on top of each other and coaxial with the rotation axis to form an air inlet and an air outlet, and the profile of each conical blade gradually widens from the air inlet toward the air outlet.

[0007] Based on the above, the axial flow cooling fan is configured with multiple conical blades arranged around the hub. These conical blades are stacked on top of each other and coaxial with the rotating axis of the hub. Therefore, it can generate an airflow field similar to that of existing axial flow fans, but can effectively avoid the noise problem of existing axial flow fans, reduce the torque requirements of the motor, and thereby increase the wind speed. Attached Figure Description

[0008] Figure 1 This is a schematic diagram of an axial cooling fan according to an embodiment of the present invention;

[0009] Figure 2 Showing it from another perspective Figure 1 axial flow cooling fan;

[0010] Figure 3A yes Figure 1 A three-dimensional cross-sectional view of an axial cooling fan;

[0011] Figure 3B yes Figure 3A A magnified view of a portion of the image;

[0012] Figure 4 This is a side view of an axial cooling fan according to another embodiment of the present invention. Detailed Implementation

[0013] Reference will now be made in detail to exemplary embodiments of the invention, examples of which are illustrated in the accompanying drawings. Wherever possible, the same component reference numerals are used in the drawings and description to denote the same or similar parts.

[0014] Figure 1 This is a schematic diagram of an axial cooling fan according to an embodiment of the present invention. Figure 2 Showing it from another perspective Figure 1 The axial-flow cooling fan. Please also refer to... Figure 1 and Figure 2 In this embodiment, the axial cooling fan 100 includes a hub 110, a plurality of conical blades 120, and a housing 130. The hub 110 has a rotation axis CX. The conical blades 120 are arranged around the hub 110 and driven by the hub 110, and the hub 110 together with the conical blades 120 is rotatably disposed within the housing 130. A motor (not shown) is connected to the hub 110, thereby driving the hub 110 and the conical blades 120 to rotate within the housing 130 about the rotation axis CX.

[0015] Here, the conical blades 120 are stacked on top of each other and coaxial with the rotation axis CX, thereby forming multiple air inlets FL1 and multiple air outlets FL2 between the inner wall of the hub 110 and the housing 130, and the outline of each conical blade 120 gradually expands from the air inlet FL1 towards the air outlet FL2. Because the conical blades 120 have a multi-layered stacked structure, when the hub 110 drives the conical blades 120 to rotate around the rotation axis CX, the airflow can... Figure 1 The multiple air inlets FL1 shown flow into the axial cooling fan 100, and from... Figure 2 The axial cooling fan 100 flows out from the multiple air outlets FL2 shown.

[0016] Figure 3A yes Figure 1A three-dimensional sectional view of an axial cooling fan. Figure 3B yes Figure 3A A magnified view of a section. Please also refer to... Figure 2 , Figure 3A and Figure 3B Furthermore, the hub 110 has a shaft portion 111 and a plurality of ribs 112, the ribs 112 extending radially from and relative to the shaft portion 111. A plurality of tapered blades 120 are attached to these ribs 112 and surround the shaft portion 111 to facilitate drive by the hub 110. Furthermore, as... Figure 3A and Figure 3B As shown, among these conical blades 120, the length of at least one conical blade 120 near the hub 110 (shaft portion 111) is less than the length of at least one conical blade 120 away from the hub 110 (shaft portion 111). Furthermore, each conical blade 120 is essentially a continuous structure surrounding the hub 110 (shaft portion 111). In other words, unlike conventional axial fans, the axial cooling fan 100 of this embodiment uses conical blades 120 with a continuous structure, thus avoiding the fixed-frequency blade passing tone generated by the aforementioned propeller blades passing through the inner wall of the housing.

[0017] In addition, such as Figure 3B As shown, if the hub 110 (shaft portion 111) and the inner wall of the housing 130 are used as structural orientation references, and the portion adjacent to the hub 110 (shaft portion 111) and away from the housing 130 is considered the inner side, while the portion adjacent to the housing 130 and away from the hub 110 (shaft portion 111) is considered the outer side, then as follows: Figure 3B As shown, the conical blade 120 near the outer side can be further divided into a conical section 121 and a guide section 122. The guide section 122 is connected to the end of the conical section 121 and is located at the air outlet FL2 (marked in...). Figure 3A The conical blades 120 near the inner side are equivalent to having only a conical portion 121 without a guide portion. This is to provide airflow guidance for the axial cooling fan 100 of this invention, that is, by making the conical blades 120 with guide portions 122 away from the hub 110 (shaft portion 111), and making the conical blades 120 without guide portions 122 adjacent to the hub 110 (shaft portion 111), so that the airflow field of the axial cooling fan 100 can be similar to that of existing axial fans.

[0018] In addition, such as Figure 3BAs shown, the slopes of the conical blades 120 in this embodiment (based on the rotation axis CX) are consistent, meaning the conical portions 121 of these blades 120 are parallel to each other, facilitating layer-by-layer stacking. Furthermore, a flow channel is formed between two parallel and adjacent conical blades 120. When the hub 110 drives the conical blades 120 to rotate around the rotation axis CX, the gas (or air) between two adjacent conical blades 120 is driven by the rotating blades 120 due to friction. Simultaneously, the rotating blades 120 generate centrifugal force F3, which is equivalent to generating two component forces F1 and F2. Component force F1 acts on the gas between the conical blades 120, while component force F2 acts as a positive force on the wall of the conical blades 120. This causes the gas between the conical blades 120 to exhibit a spiral motion, generating a spiral airflow from the inlet FL1 to the outlet FL2 in the flow channel (e.g., Figure 3A As shown by the dashed arrow, especially when the rotational speed of the conical blade 120 increases, the aforementioned centrifugal force F3 will be greater, and the spiral motion of the gas (or air) will be more obvious, thus enabling the axial cooling fan 100 of this case to generate an airflow field similar to that of an axial fan.

[0019] Furthermore, in this embodiment, the spacing of the conical blades 120 is greater than or equal to 0.4 mm. This means that the boundary layers formed by the airflow in the flow channel on the wall of the conical blades 120 overlap at the aforementioned 0.4 mm. This allows the frictional force of the boundary layers to smoothly drive the gas (or air) in the flow channel, and at this time, the static pressure of the axial cooling fan 100 can reach its maximum. This means that the airflow velocity at the outlet FL2 can reach its maximum, so the axial cooling fan 100 no longer needs to rely on the torque of the motor to increase the airflow speed (i.e., reducing the demand on the motor).

[0020] Figure 4 This is a side view of an axial cooling fan according to another embodiment of the present invention. Please refer to... Figure 4 The difference from the aforementioned embodiments is that the axial cooling fan 200 in this embodiment only includes a hub 210 and conical blades 120, and does not have the aforementioned housing 130. The reason for this is that the conical blades 120 in this embodiment can already form airflow inlets and outlets (air inlet FL1 and air outlet FL2), and at least a portion of the conical blades 120 also has a guide section 122 at the end near the air outlet FL2, which can achieve the desired airflow guiding effect. There is no limitation on the type or number of guide sections 122. In this embodiment, the spaces C1 and C2 located on the side of the air outlet FL2 can be used for extending the conical blades 120 or adding guide sections 122.

[0021] In summary, in the above embodiments of the present invention, the axial cooling fan is arranged with multiple conical blades surrounding the hub, wherein these conical blades are stacked on top of each other and coaxial with the rotating axis of the hub, thus successfully generating an airflow field similar to that of existing axial fans, but effectively avoiding the noise problem of existing axial fans, reducing the torque requirement of the motor, and thereby increasing the wind speed.

[0022] Furthermore, the flow channel formed by multiple conical blades, when the conical blades rotate, the centrifugal force component further drives the airflow along a spiral path on the conical blades, thereby enabling the axial cooling fan to generate an airflow field similar to that of existing axial fans, thus meeting current requirements for axial fans. The spacing of the conical blades can be adjusted according to needs, with a minimum spacing of 0.4mm, maximizing the current fan static pressure to increase the airflow speed from the outlet and thus reducing the torque requirements of the axial cooling fan motor. In addition, since the multiple conical blades of the axial cooling fan already form the air inlet and outlet, the housing can be removed as needed, and guide sections for the conical blades can be added or extended as required.

[0023] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention 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; and these 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 the present invention.

Claims

1. An axial flow cooling fan, characterized in that, include: A wheel hub has a rotating shaft; as well as Multiple conical blades are arranged around the hub and driven by the hub. The multiple conical blades are stacked on top of each other and coaxial with the rotation axis. The multiple conical blades form an air inlet and an air outlet, and the outline of each conical blade gradually expands from the air inlet toward the air outlet.

2. The axial flow cooling fan according to claim 1, characterized in that, It also includes a housing, in which the hub and the plurality of tapered blades are rotatably disposed.

3. The axial cooling fan according to claim 1, characterized in that, The spacing between the plurality of conical blades is greater than or equal to 0.4 mm.

4. The axial cooling fan according to claim 1, characterized in that, The hub has a shaft portion and a plurality of ribs, the shaft portion having the rotation axis, the ribs extending radially from and relative to the shaft portion, and the plurality of tapered blades being attached to the plurality of ribs and surrounding the shaft portion.

5. The axial cooling fan according to claim 1, characterized in that, Of the plurality of conical blades, at least one of the conical blades closer to the hub has a length less than at least one of the conical blades farther from the hub.

6. The axial cooling fan according to claim 1, characterized in that, Each of the conical blades is a continuous structure surrounding the hub.

7. The axial cooling fan according to claim 1, characterized in that, The conical blade has a conical portion and a guide portion, the guide portion being connected to the end of the conical portion and located at the air outlet.

8. The axial cooling fan according to claim 7, characterized in that, The guide portion of the plurality of tapered blades is located away from the hub.

9. The axial cooling fan according to claim 7, characterized in that, The one that does not have the guide portion among the plurality of tapered blades is adjacent to the hub.

10. The axial cooling fan according to claim 1, characterized in that, A flow channel is formed between two adjacent conical blades, and when the hub drives the plurality of conical blades to rotate around a rotation axis, a spiral airflow is generated in the flow channel, moving from the air inlet to the air outlet.

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