Heatsink fan structure

Abstract

A heatsink fan structure includes an impeller having a hub provided with a pivot portion rotatably mounted on the pivot portion of the housing. The hub of the impeller has a periphery provided with multiple blades that are arranged in a radiating manner. A circular fixing frame is mounted on an outer periphery of the blades. The fixing frame has a permanent magnet. The upper and lower ends of each of the blades are not protruded from the fixing frame.

Description

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] The present invention relates to a heatsink fan structure, and more particularly to a heatsink fan structure, wherein when the impeller of the heatsink fan structure is rotated, the wind shear noise produced between the impeller and the outer frame of the heatsink fan structure may be reduced.

[0003] 2. Description of the Related Art

[0004] A first conventional heatsink fan structure in accordance with the prior art shown in FIG. 8 comprises a housing 80 formed with a receiving space 81 for receiving a stator 82 which is wound with a coil. A rotor 83 has a rotation shaft 84 rotatably mounted on the stator 82. However, when the rotor 83 is rotated, a wind shear noise will produce between the outer periphery of the blades 85 of the rotor 83 and the annular wall of the receiving space 81 of the housing 80.

[0005] A second conventional heatsink fan structure in accordance with the prior art shown in FIGS. 9 and 10 is disclosed in the applicant's Taiwanese Patent Publication No. 382412, comprising a base board 90 having a shaft 91 for supporting an impeller 92 to rotate. The outer periphery of the blades 93 of the impeller 92 is combined with a magnet ring 94. The base board 90 is provided with multiple poles 95, and an outer frame 96 is mounted on the base board 90. The magnet ring 94 may induce with the poles 95 of the base board 90, so that the impeller 92 may be rotated, and the blades 93 may drive the air to flow.

[0006] The magnet ring 94 of the conventional outer pole type heatsink fan structure has a single thickness, and has a smaller height. Thus, when the magnet ring 94 is combined on the outer periphery of the blades 93, the blades 93 are protruded from the upper and lower end of the magnet ring 94. Thus, when the heatsink fan is rotated, the air introduced by the blades 93 cannot be driven toward a determined direction efficiently, and will escape sideways from a position of thickness difference formed by the distal ends of the blades 93 and the upper and lower end of the magnet ring 94. In addition, a wind shear noise will produce between the sideward escaping air flow and the peripheral poles 95.

SUMMARY OF THE INVENTION

[0007] The primary objective of the present invention is to provide a heatsink fan structure, wherein when the impeller of the heatsink fan structure is rotated, the air flow driven by the blades may be driven along the designed direction.

[0008] A secondary objective of the present invention is to provide a heatsink fan structure, wherein when the impeller of the heatsink fan structure is rotated, the wind shear noise produced between the outer periphery of the blades of the impeller and the housing of the heatsink fan structure may be reduced.

[0009] In accordance with the present invention, there is provided a heatsink fan structure includes an impeller having a hub provided with a pivot portion rotatably mounted on the pivot portion of the housing. The hub of the impeller has a periphery provided with multiple blades that are arranged in a radiating manner. A circular fixing frame is mounted on an outer periphery of the blades. The fixing frame has a permanent magnet. The upper and lower ends of each of the blades are not protruded from the fixing frame.

[0010] Further benefits and advantages of the present invention will become apparent after a careful reading of the detailed description with appropriate reference to the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

[0011] FIG. 1 is an exploded perspective view of a heatsink fan structure in accordance with a first embodiment of the present invention;

[0012] FIG. 2 is a top plan assembly view of the heatsink fan structure as shown in FIG. 1;

[0013] FIG. 3 is a cross-sectional view of the heatsink fan structure taken along line 3-3 as shown in FIG. 2;

[0014] FIG. 4 is a cross-sectional view of the heatsink fan structure taken along line 3-3 as shown in FIG. 2 in accordance with a second embodiment of the present invention;

[0015] FIG. 5 is an exploded perspective view of a heatsink fan structure in accordance with a third embodiment of the present invention;

[0016] FIG. 6 is a top plan assembly view of the heatsink fan structure as shown in FIG. 5;

[0017] FIG. 7 is a cross-sectional view of the heatsink fan structure taken along line 7-7 as shown in FIG. 6;

[0018] FIG. 8 is an exploded perspective cross-sectional assembly view of a first conventional heatsink fan structure in accordance with the prior art;

[0019] FIG. 9 is an exploded perspective cross-sectional assembly view of a second conventional heatsink fan structure in accordance with the prior art; and

[0020] FIG. 10 is a front plan cross-sectional assembly view of the heatsink fan structure as shown in FIG. 9.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0021] Referring to the drawings and initially to FIG. 1, a heatsink fan structure in accordance with a first embodiment of the present invention comprises a housing 1, an outer frame 2, and an impeller 3.

[0022] The housing 1 has a pivot portion 11 for supporting the impeller 3 to rotate. The pivot portion 11 may be a central shaft or a central hole. The pivot portion 11 has a periphery provided with even numbers of poles 12. The poles 12 may be energized, to produce a magnetic field and a current direction. The housing 1 may be provided with a circuit board which includes a sensor and other controller, for detecting the variation of polarity of the permanent magnet 35 of the impeller 3, so that the poles 12 may change the current direction and produce different alternating magnetic fields. The housing 1 is provided with combination members 14, such as barbs, and an air outlet 15. The outer frame 2 may be combined with the combination members 14 of the housing 1, and the air outlet 15 may drive the air flow toward a determined direction.

[0023] The outer frame 2 may be combined with the housing 1. As shown in the figure, the outer frame 2 may be formed with positioning holes 21 for locking the combination members 14 of the housing 1 in a snap manner. The outer frame 2 has an air inlet 22 which is preferably circular. The air inlet 22 has a periphery formed with an annular lip 23, and the air inlet 22 may be used to introduce the air flow.

[0024] The impeller 3 has a central position formed with a hub 31 which has a pivot portion 32 that may be a central shaft or a shaft hole as shown in the figure, so that the pivot portion 32 of the impeller 3 may be rotatably mounted on the pivot portion 11 of the housing 1. The hub 31 of the impeller 3 is provided with multiple blades 33 that are arranged in a radiating manner. A circular fixing frame 34 is mounted on an outer periphery of the blades 33. The circular fixing frame 34 may be made individually, or integrally formed with the impeller 3. The height of the circular fixing frame 34 is equal to or greater than that of each of the blades 33. A permanent magnet 35 is mounted on an outer periphery of the circular fixing frame 34. At least one of the upper end and the lower end of the inner periphery of the circular fixing frame 34 is formed with a horn-shaped arcuate edge 36 whose maximum diameter is greater than the diameter of the air inlet 22 of the outer frame 2.

[0025] Referring to FIGS. 2 and 3, the heatsink fan structure in accordance with the first embodiment of the present invention is assembled. The pivot portion 32 of the impeller 3 is rotatably mounted on the pivot portion 11 of the housing 1. The arcuate edge 36 of the impeller 3 is opposite to the air inlet 22 of the outer frame 2. When the permanent magnet 35 of the impeller 3 is repulsive with the magnetic field produced by the poles 12 of the housing 1, the impeller 3 may be driven to rotate. The fixing frame 34 is mounted on the outer periphery of the blades 33 of the impeller 3, and the maximum diameter of the arcuate edge 36 of the impeller 3 is greater than the diameter of the air inlet 22 of the outer frame 2. Thus, when the impeller 3 is rotated, the driven air flow may be introduced into the air inlet 22 of the outer frame 2, and may be drained outward from the air outlet 15 of the housing 1. The driven air flow is not in contact with the wall of the housing 1. Thus, when the impeller 3 is rotated, the driven air flow will not produce a wind shear problem with the wall of the housing 1, and the noise during rotation of the impeller 3 may be reduced.

[0026] Referring to FIG. 4, a heatsink fan structure in accordance with a second embodiment of the present invention is shown. The lip 23 of the outer frame 2 is formed with an arcuate protruding face 24 extended downward. The arcuate protruding face 24 is aligned with the arcuate edge 36 of the impeller 3. Thus, when the impeller 3 is rotated, the driven air flow may flow more conveniently, and may be drained outward from the air outlet 15.

[0027] Referring to FIG. 5, a heatsink fan structure in accordance with a third embodiment of the present invention comprises a housing 4, and an impeller 5.

[0028] The housing 4 is formed with a receiving space 41 which is provided with a base board 42 and an air outlet 45. The base board 42 is provided with a stator seat 43 which has a pivot portion 44 that may be may be a central shaft or a shaft hole, so that the pivot portion 52 of the impeller 5 may be rotatably mounted on the pivot portion 44 of the housing 1.

[0029] The impeller 5 has a central position formed with a hub 51 which has a pivot portion 52 that may be a rotation shaft or a shaft hole, so that the pivot portion 52 of the impeller 5 may be rotatably mounted on the pivot portion 44 of the housing 4. The hub 51 of the impeller 5 is provided with multiple blades 53 that are arranged in a radiating manner. A fixing frame 54 is mounted on an outer periphery of the blades 53. The height of the fixing frame 54 is greater than that of each of the blades 53, so that the upper end and the lower end of each of the blades 53 is not protruded from the fixing frame 54.

[0030] Referring to FIGS. 6 and 7, the heatsink fan structure in accordance with the third embodiment of the present invention is assembled.

[0031] The pivot portion 52 of the impeller 5 may be rotatably mounted on the pivot portion 44 of the housing 4. The permanent magnet 55 of the impeller 5 is repulsive with the magnetic field produced by the stator seat 43 of the housing 4, so that the impeller 5 may be driven to rotate. The fixing frame 54 is mounted on the outer periphery of the blades 53 of the impeller 5, and the thickness of the fixing frame 54 is greater than that of each of the blades 54. Thus, when the impeller 5 is rotated, the driven air flow may be introduced into the open space of the receiving space 41 of the housing 4, and may be drained outward from the air outlet 45 of the housing 4. The driven air flow is not in contact with the wall of the housing 4. Thus, when the impeller 5 is rotated, the driven air flow will not produce a wind shear problem with the wall of the housing 4, and the noise during rotation of the impeller 5 may be reduced.

[0032] Accordingly, in the heatsink fan structure of the present invention, the outer periphery of the blades of the impeller is provided with a fixing frame, and the height of the upper and lower end of the blade is smaller than that of the fixing frame, so that when the impeller is rotated, the air flow driven by the blades of the impeller will not be driven sideward from the outer periphery of the blades, and the air flow and the outer frame or the annular wall of the housing will not form a wind shear. Thus, the rotation noise of the impeller may be reduced, and rotation of the impeller will produce a larger driven air flow.

[0033] Although the invention has been explained in relation to its preferred embodiment as mentioned above, it is to be understood that many other possible modifications and variations can be made without departing from the scope of the present invention. It is, therefore, contemplated that the appended claim or claims will cover such modifications and variations that fall within the true scope of the invention.

Claims

What is claimed is:

1. A heatsink fan structure, comprising: a housing, provided with a pivot portion, multiple poles, a circuit board, and an air outlet; an outer frame, combined with the housing, the outer frame having an air inlet, the air inlet having a periphery formed with an annular lip; and an impeller, having a hub provided with a pivot portion rotatably mounted on the pivot portion of the housing, the hub of the impeller having a periphery provided with multiple blades that are arranged in a radiating manner, a circular fixing frame mounted on an outer periphery of the blades, the fixing frame having a permanent magnet, and upper and lower ends of each of the blades being not protruded from the fixing frame.

2. The heatsink fan structure as claimed in claim 1, wherein the fixing frame has a diameter greater than that of the air inlet of the outer frame.

3. The heatsink fan structure as claimed in claim 1, wherein at least one of the upper end and the lower end of the inner periphery of the fixing frame is formed with a horn-shaped arcuate edge.

4. The heatsink fan structure as claimed in claim 3, wherein the lip of the outer frame is extended downward, and has a curvature the same as that of the arcuate edge of the fixing frame.

5. A heatsink fan structure, comprising: a housing, having a receiving space provided with a base board and an air outlet, the base board provided with a stator seat, the stator seat having a pivot portion; and an impeller, having a hub provided with a pivot portion rotatably mounted on the pivot portion of the housing, the hub having a permanent magnet that is repulsive to a magnetic field produced by the stator seat of the housing, the hub of the impeller having a periphery provided with multiple blades, a fixing frame mounted on an outer periphery of the blades, and upper and lower ends of each of the blades being not protruded from the fixing frame.