AXIAL FAN

Description

CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority to U.S. Provisional Application Ser. No. 63/559,882, filed Mar. 1, 2024, which is incorporated herein by reference in its entirety.

BACKGROUND

Field of Disclosure

The present disclosure relates to an axial fan, and more particularly to an axial fan with a noise reduction functionality.

Description of Related Art

The ribs of the fan frame of a conventional axial fan are located on an air outlet side of the fan frame, and there is no rib structure on the air inlet side of the fan frame. If it is necessary to prevent the rotating impeller from being interfered with on the air inlet side, a fan guard needs to be installed over there. However, adding a fan guard will create additional noise.

SUMMARY

The present disclosure provides an axial fan to deal with the needs of the prior art problems.

In one or more embodiments, an axial fan includes a fan frame, a motor, and an impeller. The fan frame includes an outer frame body and a mounting portion, wherein the outer frame body and the mounting portion are connected by a plurality of ribs. The motor is located on the mounting portion and has an electrical connection cable spanning between the outer frame body and the mounting portion, wherein a first rib of the ribs closest to the electrical connection cable has an arc-shaped airflow mitigation structure. The impeller is pivotally connected to the motor.

In one or more embodiments, the impeller is driven by the motor to rotate such that airflows are input from an air inlet side of the fan frame and output from an air outlet side of the fan frame, the airflow mitigation structure is located at the air inlet side of the first rib.

In one or more embodiments, the ribs, except for the first rib, comprises a plurality of second ribs having airflow guiding inclined surfaces.

In one or more embodiments, the airflow guiding inclined surface of the first rib is opposite to a rotation direction of the impeller of the axial fan.

In one or more embodiments, the electrical connection cable comprises a flexible printed circuit board.

In one or more embodiments, an axial flow channel is defined among the outer frame body, the mounting portion and the ribs. The outer frame body has a chamfered peripheral edge at an inner edge of the air outlet side facing the axial flow channel.

In one or more embodiments, the ribs include three ribs, and three central angles, formed by lines connecting the three ribs and a center of the mounting portion, are not equal.

In one or more embodiments, the impeller includes a plurality of blades, and gap widths between free ends of the blades have three different sizes.

In one or more embodiments, a windward side of each blade has a plurality of convex flow-guiding structures.

In one or more embodiments, an axial fan includes a fan frame, a motor, and an impeller. The fan frame includes an outer frame body and a mounting portion, wherein the outer frame body and the mounting portion are connected by a plurality of ribs. The motor is located on the mounting portion and has an electrical connection cable overlapping a first rib of the ribs. The impeller is pivotally connected to the motor.

In one or more embodiments, the first rib has a greater width than that of the other ribs of the ribs.

In one or more embodiments, the first rib has airflow guiding inclined surfaces.

In one or more embodiments, the first rib has a greater width than that of the electrical connection cable.

In one or more embodiments, the impeller includes a plurality of blades, and a windward side of each blade has a plurality of convex flow-guiding structures.

In sum, the axial fan disclosed herein has the ribs of the fan frame designed to be on the air inlet side so as to avoid using the fan guard, and the ribs of the fan frame are designed to have a noise reduction function. In addition, the gap widths between the free ends of the blades of the axial fan have different sizes and have a plurality of convex flow-guiding structures on the windward side, which also has a noise reduction function.

It is to be understood that both the foregoing general description and the following detailed description are by examples, and are intended to provide further explanation of the disclosure as claimed.

BRIEF DESCRIPTION OF THE DRAWINGS

The disclosure can be more fully understood by reading the following detailed description of the embodiment, with reference made to the accompanying drawings as follows:

FIG. 1 illustrates a perspective view of an axial fan according to an embodiment of the present disclosure;

FIG. 2 illustrates a perspective view of the axial fan in FIG. 1 with its impeller removed;

FIG. 3 illustrates a fan frame of the axial fan in FIG. 1;

FIG. 4 illustrates a side view of a 7-blade impeller of an axial fan according to some embodiments of the present disclosure;

FIG. 5 illustrates three cross-sectional views of the 7-blade impeller in FIG. 4 along three section lines;

FIG. 6 illustrates a side view of a 9-blade impeller of an axial fan according to some embodiments of the present disclosure;

FIG. 7 illustrates three cross-sectional views of the 9-blade impeller in FIG. 6 along three section lines;

FIG. 8 illustrates a top view of the 9-blade impeller in FIG. 6; and

FIG. 9 illustrates a perspective view of an axial fan with its impeller removed according to another embodiment of the present disclosure.

DETAILED DESCRIPTION

Reference will now be made in detail to the present embodiments of the disclosure, examples of which are illustrated in the accompanying drawings. Wherever possible, the same reference numbers are used in the drawings and the description to refer to the same or like parts. In the embodiments and patent claims, unless otherwise specified in the context, “a”, “an” and “the” may refer to a single or plural number.

Reference is made to FIG. 1, which illustrates a perspective view of an axial fan 100 according to an embodiment of the present disclosure. The axial fan 100 includes a fan frame 110, a motor 150 (see FIG. 2) and an impeller 120. The impeller 120 is driven by the motor 150 to rotate so that airflows are input from the air inlet side of the fan frame 110 and output from the air outlet side. As shown in the figure, the arrow A shows the direction of airflows in and out of impeller 120. The fan frame 110 includes an outer frame body 110a and a mounting portion 110b, wherein the outer frame body 110a and the mounting portion 110b are connected by a plurality of ribs 112. In some embodiments of the present disclosure, the ribs 112 include a rib 112a, a rib 112b, and a rib 112c. In some embodiments of the present disclosure, the rib 112a has an airflow guiding inclined surface 116a, and the rib 112b has an airflow guiding inclined surface 116b. Taking the rib 112a as an example, the airflow guiding inclined surface 116a thereof presents an inclined surface in the direction of the air inlet side. The inclined surface generally faces a direction r, which is opposite to a rotation direction R of the impeller 120. This design helps reduce the turbulence generated by the axial fan during operation and further improves high-frequency noise.

Referring again to FIG. 1, the rib 112c is closest to the electrical connection cable 114 and has an arc-shaped airflow mitigation structure 113. The airflow mitigation structure 113 is located at the air inlet side of the rib 112c, and can also be used to reduce the high-frequency noise generated when the axial fan is operating. In addition, the outer frame body 110a may further include a connection cable buckle 117 for receiving the electrical connection cable 114.

Reference is made to FIG. 2, which illustrates a perspective view of the axial fan 100 in FIG. 1 with its impeller 120 removed. This figure is a perspective view from the air outlet side. Referring FIGS. 1 and 2, the motor 150 is located on the circuit board 152 and is located on the mounting portion 110b, and the electrical connection cable 114 extending from the motor 150 spans between the outer frame body 110a and the mounting portion 110b. The motor 150 is pivotally connected to the impeller 120. In some embodiments of the present disclosure, the electrical connection cable 114 is a flexible printed circuit board. The electrical connection cable 114 not only spans the outer frame body 110a and the mounting portion 110b, but also has an electrical connector head 156 for connecting to an external control source. The outer frame body 110a has a chamfered peripheral edge 111a at an inner edge 111b of the air outlet side facing the axial flow channel 115, which helps to increase the air flow rate of the axial flow channel and reduce the noise generated when the axial fan is operating.

Reference is made to FIG. 3, which illustrates a fan frame 110 of the axial fan in FIG. 1. This figure is a view from the air outlet side of the fan frame 110. In some embodiments of the present disclosure, each of the ribs 112a, 112b, 112c has arc-shaped chamfers A1 and A2 on both sides of the connection between the ribs 112a, 112b, 112c and the outer frame body 110a. Since the viewing angle width of the arc-shaped chamfers A1 and A2 is larger, it is beneficial for the structural strength of the connection between the ribs and the outer frame body to enhance the shock resistance when falling, and further reduces the high-frequency noise generated by the operation of the axial fan.

Continuing with reference to FIG. 3, in some embodiments of the present disclosure, an axial flow channel 115 is formed between the outer frame body 110a, the mounting portion 110b, and the ribs 112a, 112b, and 112c. The three central angles A3, A4, and A5 formed by the lines connecting the ribs 112a, 112b, and 112c and a center of the mounting portion 110b are not equal, or the central angle A3 is greater than the central angle A4, and the central angle A4 is greater than the central angle A5. The change in the size of the axial flow channel 115 results in different air inlet velocities, which helps reduce noise by weakening the mutual influence of broadband noise at different wind speeds.

Reference is made to FIG. 4, which illustrates a side view of a 7-blade impeller 120a of an axial fan according to some embodiments of the present disclosure. The impeller 120a includes a plurality of blades 121 with a vertical height H1, and section lines (A-A, B-B, C-C) divide the vertical height H1 of the impeller 120a into four equal parts. The windward side 121a of each blade 121 includes a plurality of convex flow-guiding structures, but the leeward side 121b of each blade 121 is substantially smooth without any convex flow-guiding structures. The plurality of convex flow-guiding structures on the windward side 121a of the blade 121 are used to reduce the high-frequency noise generated when the axial fan is operating.

Reference is made to FIG. 5, which illustrates three cross-sectional views of the 7-blade impeller in FIG. 4 along three section lines (A-A, B-B, C-C). Referring to both FIGS. 4 and 5, in the cross-sectional view taken along section line A-A, a plurality of convex flow-guiding structures (122a, 122b) are shown on the windward side 121a. In the cross-sectional view along the section line B-B, a plurality of convex flow-guiding structures (122a, 122b) are still shown on the windward side 121a. In the cross-sectional view along the section line C-C, the windward side 121a does not have the convex flow-guiding structure (122a, 122b). In summary, the convex flow-guiding structure (122a, 122b) of the impeller 120a are only distributed on the windward side 121a of the section lines A-A and B-B, that is, they are only distributed at three quarters of the vertical height H1 from the windward surface.

Reference is made to FIG. 6, which illustrates a side view of a 9-blade impeller 120b of an axial fan according to some embodiments of the present disclosure. The impeller 120b includes a plurality of blades 123, forming a vertical height H2, and the section lines (A-A, B-B, C-C) divide the vertical height H2 of the impeller 120a into four equal parts. The windward side 123a of each blade 123 includes a plurality of protruding flow-guiding structures, but the leeward side 123b of each blade 123 is substantially smooth. The plurality of convex flow-guiding structures on the windward side 123a of the blade 123 are used to reduce the high-frequency noise generated when the axial fan is operating.

Reference is made to FIG. 7, which illustrates three cross-sectional views of the 9-blade impeller 120b in FIG. 6 along three section lines (A-A, B-B, C-C). Referring to both FIGS. 6 and 7, in the cross-sectional view along the section line A-A, a plurality of convex flow-guiding structures (124a, 124b) are shown on the windward side 123a, and the leeward side 123b is smooth. In the cross-sectional view along the section line B-B, a plurality of convex flow-guiding structures (124a, 124b) are still shown on the windward side 123a, while the leeward side 123b is smooth. In the cross-sectional view along the section line C-C, a plurality of convex flow-guiding structures (124a, 124b) are still shown on the windward side 123a, while the leeward side 123b is smooth. Based on the three cross-sectional views, the windward side 123a of each blade 123 has at least a plurality of convex flow-guiding structures (124a, 124b).

Referring again to FIG. 7, the convex flow-guiding structures (124a, 124b) on the windward side 123a of the impeller 120b are distributed on the windward side 123a, and at a vertical height H2, the convex flow-guiding structures (124a, 124b) have different heights. Furthermore, the convex flow-guiding structures (124a, 124b) have a maximum height in the cross-sectional view along the cross-sectional line B-B, and have a smaller height in the cross-sectional view along the cross-sectional line A-A and in the cross-sectional view along the cross-sectional line C-C. In other words, the height of the convex flow-guiding structure gradually increases from the cross section of the section line A-A to the cross section of the section line B-B, which reaches the maximum, and then gradually decreases to the cross section of the section line C-C.

Reference is made to FIG. 8, which illustrates a top view of the 9-blade impeller 120b in FIG. 6. In some embodiments of the present disclosure, the impeller 120b includes a plurality of blades 123, and the gap widths (D1, D2, D3) between free ends of adjacent blades of the blades 123 have three different sizes. The design of different gap widths (D1, D2, D3) between adjacent blades 123 is also helpful in reducing the high-frequency noise generated when the axial fan is operating.

Reference is made to FIG. 9, which illustrates a perspective view of an axial fan with its impeller removed according to another embodiment of the present disclosure. The difference between this example and the embodiments of FIGS. 1 and 2 lies in the design of the fan frame 110′. Specifically, the specific structure of the ribs of the fan frame 110′ is different. The ribs (112a, 112b) of fan frame 110′ and fan frame 110 are the same and are both designed to reduce operating noise, but the ribs 112d and 112c are different. The rib 112a has an airflow mitigation structure 113 to reduce the high frequency noise generated when the axial fan is operating. The rib 112d is designed to overlap the electrical connector 152a. The circuit board 152 is electrically coupled to the circuit board 154 via the electrical connector 152a and is connected to an external control source via the electrical connector head 156. In some embodiments of the present disclosure, the rib 112d has a larger width W2 than the other ribs (112b, 112c). In some embodiments of the present disclosure, the width W2 of the rib 112d is greater than the width W1 of the electrical connector 152a. In some embodiments of the present disclosure, the electrical connector 152a may be molded into the rib 112d by an injection molding process. The motor 150 is located on the circuit board 152 and is located on the mounting portion 110b. In above embodiments, the impeller (120, 120a, 120b) is pivotally connected to the motor 150.

In sum, the axial fan disclosed herein has the ribs of the fan frame designed to be on the air inlet side so as to avoid using the fan guard, and the ribs of the fan frame are designed to have a noise reduction function. In addition, the gap widths between the free ends of the blades of the axial fan have different sizes and have a plurality of convex flow-guiding structures on the windward side, which also has a noise reduction function. Although the present disclosure has been described in considerable detail with reference to certain embodiments thereof, other embodiments are possible. Therefore, the spirit and scope of the appended claims should not be limited to the description of the embodiments contained herein.