Axial fan

Abstract

An axial flow fan comprises a fan frame, a motor and an impeller. The fan frame comprises an outer frame body and a mounting part, wherein the outer frame body is connected with the mounting part through a plurality of ribs. The motor is located on the installation portion and provided with a flat cable spanning between the outer frame body and the installation portion, and at least one first rib of the ribs is provided with an air flow slowing structure. The motor is pivoted with the impeller.

Description

Technical Field

[0001] The present invention relates to an axial flow fan, and in particular to an axial flow fan with reduced noise. Background Art

[0002] Existing axial-flow fans have ribs on the fan frame's outlet side, but no ribs on the air inlet side. To prevent interference with the rotating impeller on the air inlet side, a fan guard must be installed. However, this creates additional noise. Summary of the Invention

[0003] The present invention provides an axial flow fan to solve the problems of the prior art.

[0004] According to some embodiments of the present invention, an axial-flow fan includes a fan frame, a motor, and an impeller. The fan frame includes an outer frame and a mounting portion, wherein the outer frame and the mounting portion are connected by a plurality of ribs. The motor is located in the mounting portion, and a cable extends from the motor and spans between the outer frame and the mounting portion. At least one first rib of the ribs has an airflow mitigation structure. The motor is pivotally connected to the impeller.

[0005] According to some embodiments of the present invention, an impeller pivotally connected to a motor is driven to rotate so that air is sucked in from the air inlet side of the fan frame and discharged from the air outlet side, and the air flow mitigation structure is located on the air inlet side of the first rib.

[0006] According to some embodiments of the present invention, the airflow mitigation structure of the ribs except the first rib is an airflow guiding inclined surface.

[0007] According to some embodiments of the present invention, the airflow guide slope of the first rib is opposite to the rotation direction of the axial flow impeller.

[0008] According to some embodiments of the present invention, the cable includes a flexible printed circuit board.

[0009] According to some embodiments of the present invention, an axial flow channel is formed between the outer frame, the mounting portion, and the ribs, and the outer frame has a chamfered peripheral edge at the inner edge of the air outlet side facing the axial flow channel.

[0010] According to some embodiments of the present invention, the ribs include three ribs, and three central angles formed by lines connecting the three ribs and the center of the mounting portion are all unequal.

[0011] According to some embodiments of the present invention, the impeller includes a plurality of blades, and the gap widths between the free ends of the blades have three different sizes.

[0012] According to some embodiments of the present invention, the windward sides of the blades have a plurality of raised flow-guiding structures.

[0013] According to some embodiments of the present invention, an axial-flow fan includes a fan frame, a motor, and an impeller. The fan frame includes an outer frame and a mounting portion, wherein the outer frame and the mounting portion are connected by a plurality of ribs. The motor is located in the mounting portion and has an electrical connector that overlaps with one of the ribs. The motor and the impeller are pivotally connected.

[0014] According to some embodiments of the present invention, the rib has a larger width than other ribs.

[0015] According to some embodiments of the present invention, the first rib has an airflow guiding inclined surface.

[0016] According to some embodiments of the present invention, the width of the rib overlapping the electrical connector is greater than the width of the electrical connector.

[0017] According to some embodiments of the present invention, the impeller includes a plurality of blades, and the windward sides of the blades have a plurality of protruding flow-guiding structures.

[0018] In summary, the axial-flow fan of the present invention features a fan frame with ribs positioned on the windward side, eliminating the need for a fan guard. The fan frame ribs are also designed to provide noise reduction. Furthermore, the gaps between the free ends of the axial-flow fan blades are available in a variety of sizes, and the fan has multiple raised airflow guide structures on the windward side, further contributing to noise reduction.

[0019] The above description will be described in detail below with reference to implementation examples, and a further explanation of the technical solution of the present invention will be provided. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] To make the above and other objects, features, advantages and embodiments of the present invention more apparent, the following descriptions of the accompanying drawings are given:

[0021] Figure 1 is a perspective view showing an axial flow fan according to an embodiment of the present invention;

[0022] Figure 2 It shows Figure 1 A three-dimensional image of an axial flow fan with the impeller removed;

[0023] Figure 3 It shows Figure 1 The fan frame of the axial flow fan;

[0024] Figure 4 is a side view showing a 7-blade impeller of an axial flow fan according to some embodiments of the present invention;

[0025] Figure 5 It shows Figure 4 Cross-section of a 7-blade impeller along three section lines;

[0026] Figure 6is a side view showing a 9-blade impeller of an axial flow fan according to some embodiments of the present invention;

[0027] Figure 7 It shows Figure 6 Cross-section of a 9-blade impeller along three section lines;

[0028] Figure 8 It shows Figure 6 a top view of a 9-blade impeller; and

[0029] Figure 9 FIG. 1 is a perspective view showing an axial flow fan with an impeller removed according to another embodiment of the present invention.

[0030] Description of reference numerals:

[0031] 100: Axial fan

[0032] 110, 110': fan frame

[0033] 110a: outer frame

[0034] 110b: Installation

[0035] 111a: Chamfered edge

[0036] 111b: Inner edge

[0037] 112, 112a, 112b, 112c, 112d: ribs

[0038] 113: Airflow mitigation structure

[0039] 114: Cable

[0040] 115: Axial flow channel

[0041] 116a, 116b: airflow guide slope

[0042] 117: Wire buckle

[0043] 120, 120a, 120b: Impeller

[0044] A1, A2: Arc chamfer

[0045] A3, A4, A5: Central angle

[0046] AA, BB, CC: hatching

[0047] 121, 123: leaves

[0048] 121a, 123a: Windward side

[0049] 121b, 123b: leeward side

[0050] 122a, 122b, 124a, 124b: raised flow guide structure

[0051] A: Airflow direction

[0052] H1, H2: vertical height

[0053] D1, D2, D3: Gap width

[0054] R, r: direction

[0055] W1, W2: width

[0056] 150: Motor

[0057] 152: Circuit board

[0058] 152a: Electrical connector

[0059] 154: Circuit Board

[0060] 156: Electrical connector DETAILED DESCRIPTION

[0061] For a more detailed and complete description of the present invention, reference is made to the accompanying drawings and various embodiments described below. Like numbers in the drawings represent identical or similar elements. Well-known elements and steps are not described in the embodiments to avoid unnecessary limitations on the present invention. In the embodiments and claims, unless the context specifically dictates otherwise, the words "a," "an," and "the" may refer to a single or plural number.

[0062] Please refer to Figure 1 , which shows a three-dimensional view of an axial flow fan 100 from the wind inlet side according to an embodiment of the present invention. The axial flow fan 100 includes a fan frame 110, a motor 150 (refer to Figure 2 ) and the impeller 120. The impeller 120 is driven by the motor 150 to rotate so that the air flow is sucked in from the air inlet side of the fan frame 110 and discharged from the air outlet side. As shown in the figure, arrow A shows the direction of the air flow in and out of the impeller 120. The fan frame 110 includes an outer frame 110a and a mounting portion 110b, wherein the outer frame 110a and the mounting portion 110b are connected by a plurality of ribs 112. In some embodiments of the present invention, the ribs 112 include ribs 112a, ribs 112b and ribs 112c. In some embodiments of the present invention, the rib 112a has an air flow guide slope 116a, and the rib 112b has an air flow guide slope 116b. Taking the rib 112a as an example, its air flow guide slope 116a presents an inclined surface in the direction of the air inlet side, and this inclined surface is generally facing a direction r, which is opposite to the rotation direction R of the impeller 120. This design helps reduce turbulence generated by axial-flow fans, further improving high-frequency noise.

[0063] Continued reference Figure 1 Rib 112c is closest to the cable 114 and features a curved airflow mitigation structure 113. Located on the air inlet side of rib 112c, airflow mitigation structure 113 also serves to reduce high-frequency noise generated by the axial fan during operation. Furthermore, outer frame 110a may further include a cable clip 117 for housing the cable 114.

[0064] Please refer to Figure 2 , which shows Figure 1 The axial fan 100 is a three-dimensional diagram after removing the impeller 120. This figure is a three-dimensional diagram from the air outlet side. Figure 1 and Figure 2 The motor 150 is disposed on a circuit board 152 and is located on the mounting portion 110b. The cable 114 extending from the motor 150 spans between the outer frame 110a and the mounting portion 110b. The motor 150 is pivotally connected to the impeller 120. In some embodiments of the present invention, the cable 114 is a flexible printed circuit board. The cable 114 not only spans the outer frame 110a and the mounting portion 110b, but also has an electrical connector 156 for connection to an external control source. The outer frame 110a has a chamfered edge 111a on the inner edge 111b of the air outlet side facing the axial flow channel 115, which helps to increase the airflow rate of the axial flow channel and reduce the noise generated when the axial flow fan is in operation.

[0065] Please refer to Figure 3 , which shows Figure 1 The fan frame 110 of an axial-flow fan is shown in this figure from the air outlet side. In some embodiments of the present invention, each rib 112a, 112b, 112c has curved chamfers A1 and A2 on either side of its connection with the outer frame 110a. The wider curved chamfers A1 and A2, as seen from the perspective of the illustration, enhance the structural strength of the rib-to-outer frame connection, improve shock resistance in the event of a fall, and further reduce the high-frequency noise generated by the axial-flow fan during operation.

[0066] Continued reference Figure 3 In some embodiments of the present invention, an axial flow channel 115 is formed between the outer frame 110a, the mounting portion 110b, and the ribs 112a, 112b, and 112c. The three central angles A3, A4, and A5 defined by the lines connecting the ribs 112a, 112b, and 112c with the center of the mounting portion 110b are all unequal, or central angle A3 is greater than central angle A4, and central angle A4 is greater than central angle A5. The varying size of the axial flow channel 115 results in varying inlet air velocities, which contributes to noise reduction by reducing the frequency interaction of broadband noise at different wind speeds.

[0067] Please refer to Figure 4, which shows a side view of a seven-blade impeller 120a of an axial flow fan according to some embodiments of the present invention. Impeller 120a includes a plurality of blades 121, forming a vertical height H1. Section lines (AA, BB, CC) divide vertical height H1 of impeller 120a into four equal parts. The windward side 121a of each blade 121 includes a plurality of raised guide structures, while the leeward side 121b is substantially smooth and lacks a raised guide structure. The plurality of raised guide structures on the windward side 121a of blade 121 are used to reduce the high-frequency noise generated during operation of the axial flow fan.

[0068] Please refer to Figure 5 , which shows Figure 4 Cross-sectional views of a 7-blade impeller along three section lines (AA, BB, CC). Referring also to Figures 4 and 5, in the cross-sectional view along section line AA, a plurality of raised guide structures (122a, 122b) are shown on the windward side 121a. In the cross-sectional view along section line BB, a plurality of raised guide structures (122a, 122b) are again shown on the windward side 121a. In the cross-sectional view along section line CC, no raised guide structures (122a, 122b) are shown on the windward side 121a. In summary, the raised guide structures (122a, 122b) of the impeller 120a are only distributed on the windward side 121a along section lines AA and BB, that is, only distributed at three-quarters of the vertical height H1 from the windward surface.

[0069] Please refer to Figure 6 , which shows a side view of a nine-blade impeller 120b of an axial flow fan according to some embodiments of the present invention. Impeller 120b includes a plurality of blades 123, defining a vertical height H2. Section lines (AA, BB, CC) divide vertical height H2 of impeller 120a into four equal parts. The windward side 123a of each blade 123 includes a plurality of raised guide structures, while the leeward side 123b is substantially smooth. The plurality of raised guide structures on the windward side 123a of blade 123 are intended to reduce high-frequency noise generated during operation of the axial flow fan.

[0070] Please refer to Figure 7 , which shows Figure 6Cross-sectional views of the nine-blade impeller 120b along three section lines (AA, BB, CC). Referring to Figures 6 and 7 , in the cross-sectional view along section line AA, the windward side 123a displays a plurality of raised flow-guiding structures (124a, 124b), while the leeward side 123b is smooth. In the cross-sectional view along section line BB, the windward side 123a still displays a plurality of raised flow-guiding structures (124a, 124b), while the leeward side 123b is smooth. In the cross-sectional view along section line CC, the windward side 123a still displays a plurality of raised flow-guiding structures (124a, 124b), while the leeward side 123b is smooth. Based on the above three cross-sectional views, each blade 123 has at least a plurality of raised flow-guiding structures (124a, 124b) on its windward side 123a.

[0071] Continued reference Figure 7 The raised guide 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 raised guide structures (124a, 124b) have different heights. Furthermore, the raised guide structures (124a, 124b) have a maximum height in the cross-sectional view along section line BB, and a smaller height in the cross-sectional views along section line AA and section line CC. In other words, the height of the raised guide structures gradually increases from the cross-sectional view along section line AA to the cross-sectional view along section line BB, reaching a maximum, and then gradually decreases to the cross-sectional view along section line CC.

[0072] Please refer to Figure 8 , which shows Figure 6 A top view of a nine-blade impeller 120b. In some embodiments of the present invention, the impeller 120b includes a plurality of blades 123, with the gap widths (D1, D2, D3) between the free ends of adjacent blades 123 having three different sizes. The different gap widths (D1, D2, D3) between adjacent blades 123 also help reduce high-frequency noise generated during axial fan operation.

[0073] Please refer to Figure 9, which shows a three-dimensional view of an axial flow fan with the impeller removed according to another embodiment of the present invention. The difference between this example and the embodiments of Figures 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 the fan frame 110' and the fan frame 110 are the same, both having a design 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 flow fan is in operation. 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 156. In some embodiments of the present invention, the rib 112d has a larger width W2 than the other ribs (112b, 112c). In some embodiments of the present invention, the width W2 of the rib 112d is greater than the width W1 of the electrical connector 152a. In some embodiments of the present invention, the electrical connector 152a may be incorporated into the rib 112d via an injection molding process. The motor 150 is disposed on the circuit board 152 and positioned on the mounting portion 110b. In the above-described embodiment, the motor 150 is pivotally connected to the impellers 120, 120a, and 120b.

[0074] The axial flow fan of the present invention has its fan frame ribs designed on the windward side, eliminating the need for a fan guard and designing the fan frame ribs to have a noise reduction function. Furthermore, the gap widths between the free ends of the axial flow fan blades have various sizes, and the fan has multiple raised guide structures on its windward side, which also have a noise reduction function. Although the present invention has been disclosed above in terms of embodiments, this is not intended to limit the present invention. Any person skilled in the art may make various changes and modifications without departing from the concept and scope of the present invention. Therefore, the scope of protection of the present invention shall be based on the scope of the patent application.

Claims

1. An axial flow fan, comprising: A fan frame comprises an outer frame and a mounting portion, wherein the outer frame and the mounting portion are connected by a plurality of ribs; a motor located in the mounting portion and having a cable spanning between the outer frame and the mounting portion, wherein a first rib of the plurality of ribs closest to the cable has an arc-shaped airflow mitigation structure; and An impeller is pivotally connected to the motor.

2. The axial flow fan as claimed in claim 1, wherein the impeller is driven by the motor to rotate so that air is sucked in from the air inlet side of the fan frame and discharged from the air outlet side, and the air flow reduction structure is located on the air inlet side of the first rib. 3 . The axial-flow fan as claimed in claim 1 , wherein the airflow mitigation structure is located on a side of the first rib closer to the cable. 4 . The axial-flow fan as claimed in claim 1 , wherein two sides of a connection between each of the plurality of ribs and the outer frame have arc-shaped chamfers. 5 . The axial-flow fan as claimed in claim 1 , wherein the second ribs other than the first rib have airflow guiding inclined surfaces. The axial-flow fan as claimed in claim 1 , wherein the cable comprises a flexible printed circuit board. 7 . The axial flow fan as claimed in claim 2 , wherein an axial flow channel is formed between the outer frame, the mounting portion and the plurality of ribs, and the outer frame has a chamfered peripheral edge at an inner edge of the air outlet side facing the axial flow channel. 8 . The axial-flow fan according to claim 1 , wherein the plurality of ribs include three ribs, and three central angles formed by connecting lines between the three ribs and the center of the mounting portion are all unequal. 9 . The axial flow fan as claimed in claim 1 , wherein the impeller comprises a plurality of blades, and the gap widths between the free ends of the plurality of blades have three different sizes. 10 . The axial flow fan as claimed in claim 9 , wherein the windward side of the plurality of blades has a plurality of protruding flow-guiding structures.

11. An axial flow fan, comprising: A fan frame comprises an outer frame and a mounting portion, wherein the outer frame and the mounting portion are connected by a plurality of ribs; a motor located at the mounting portion and having an electrical connector overlapping a first rib of the plurality of ribs; and An impeller is pivotally connected to the motor. 12 . The axial flow fan as claimed in claim 11 , wherein the first rib has a larger width than the other ribs. 13 . The axial-flow fan as claimed in claim 11 , wherein the second ribs other than the first rib have airflow guiding inclined surfaces. The axial flow fan as claimed in claim 11 , wherein a width of the first rib is greater than a width of the electrical connection member. 15 . The axial flow fan as claimed in claim 11 , wherein the impeller comprises a plurality of blades, and a windward side of the plurality of blades has a plurality of protruding flow-guiding structures.

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