COMBINATION AXIAL-FLOW FAN

Abstract

A high-performance low-noise combination axial-flow fan includes a fan hub that has a center connection portion for the connection of a fan motor shaft and a plurality of mounting grooves equiangularly spaced around the periphery, and fan blades each having a wedge block disposed at the inner end for insertion into one mounting groove to secure the respective fan blade to the fan hub so that the fan blades are radially fastened to the fan hub and no gap is seen between each two adjacent fan blades when viewed from the front side.

Description

BACKGROUND OF THE INVENTION

(a) Field of the Invention

The present invention relates to a fan and more particularly, to a combination axial-flow fan for use in a computer or electronic product for forced air convection cooling.

(b) Description of the Prior Art

Regular cooler modules are designed for use in electronic and photoelectric products to expel waste heat. A typical conventional cooler module is comprised of a passive heat dissipation device and an active heat dissipation device. A passive heat dissipation device can be a heat sink extruded from copper or aluminum and having multiple radiation fins. An active heat dissipation device can be an axial-flow fan that forces surrounding air to cause convection, thereby lowering the surrounding temperature. A typical conventional axial-flow fan comprises a fan hub 10 and multiple blades 20 integrated into and extending around the periphery of the fan hub 10 (see FIG. 6). By means of controlling a motor to rotate the fan hub 10, the blades 20 produce a wind pressure, achieving force-air cooling Because the parameters of 3D camber, angle, number and radius of the fan blades determine the wind pressure, pressure amount and noise levels, it is the optimum design where there is no gap structure seen in the fan blades when viewed from the front side, i.e., the front edge of one fan blade blocks the rear edge of another adjacent fan blade.

However, this design is not applicable due to technical problems in molding technology. A partial fan blade overlapping arrangement will result in a mold stripping problem after injection molding. Therefore, there is a gap d' between each two adjacent fan blades 20 (see FIG. 6), allowing removal of the molded fan from the mold. The presence of this gap d' is one of the major reasons of the production of wind noise. It also tends to cause an insufficient wind pressure problem, which presents difficulties in satisfying heat dissipation requirements of modern electronic devices.

SUMMARY OF THE INVENTION

The present invention has been accomplished under the circumstances in view. It is therefore one object of the present invention to provide a combination axial-flow fan, which has the fan hub and the fan blades separately made and then assembled together so that the front edge of one fan blade is suspended above the rear edge of another fan blade, no gap is seen between each two adjacent fan blades when viewed from the front side, and has high wind pressure, high wind capacity and low noise level characteristics.

To achieve this and other objects of the present invention, the combination axial-flow fan comprises a fan hub and a set of fan blades. The fan hub and the fan blades are separately made and then assembled together. The fan hub comprises a center connection portion for the connection of a fan motor shaft, and a plurality of mounting grooves equiangularly spaced around the periphery. Each fan blade comprises a wedge block disposed at the inner end. The wedge block can be inserted through the rear open side of one mounting groove to secure the respective fan blade to the periphery of the fan hub. The mounting grooves can be dovetail grooves. In this application, the mounting grooves are dovetail grooves, and the wedge block of each fan blade is a dovetail block fitting the dovetail configuration of the mounting grooves.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an exploded view of a combination axial-flow fan according to the present invention.

FIG. 2 is an assembly view of the combination axial-flow fan according to the present invention.

FIG. 3 is a sectional view of a part of the present invention, showing the dovetail mounting grooves of the fan hub.

FIG. 4 is a sectional elevation of the combination axial-flow fan according to the present invention.

FIG. 5 is a front view of the combination axial-flow fan according to the present invention.

FIG. 6 is a schematic front view of an axial-flow fan according to the prior art.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

With reference to FIGS. 1 and 2, a combination axial-flow fan in accordance with the present invention comprises a fan hub 1 and a plurality of fan blades 2. The fan hub 1 and the fan blades 2 are separately molded from plastics by means of injection molding, and then assembled together for use as an active heat dissipation device for the cooling of an electronic product.

Referring to FIGS. 1 and 2 again, the fan hub 1 may be made in any of a variety of shapes. According to the present preferred embodiment, the fan hub 1 is shaped like a round cap, having a center connection portion 11 at the center for the connection of the shaft of a fan motor (not shown), and a plurality of mounting grooves 12 equiangularly spaced around the periphery. The mounting grooves 12 can be dovetail grooves extending axially towards the rear side 13 of the fan hub 1 so that each mounting groove 12 has an open end 121 at the rear side 13 of the fan hub 1.

Referring to FIGS. 1 and 2 again, the fan blades 2 are identical in shape, each having a front edge 21, a rear edge 22, an outer edge 23 and an inner edge 24. There are no particular limitations on the 3D camber and geometric shape of the fan blades 2. The 3D camber and geometric shape of the fan blades 2 can be modified to achieve optimum performance subject to aerodynamics. Each fan blade 2 further has a wedge block 25. The wedge block 25 is a dovetail block fitting the circular shape of the periphery of the fan hub 1 for engagement into one mounting groove 12 of the fan hub 1. By means of engaging the wedge blocks 25 of the fan blades 2 into the mounting grooves 12 of the fan hub 1, the fan blades 2 are fastened to the fan hub 1 and radially equiangularly spaced around the periphery of the fan hub 1.

After installation, as shown in FIG. 2, the fan blades 2 are radially disposed around the fan hub 1 and equiangularly spaced from one another. Thereafter, the center connection portion 11 of the fan hub 1 is fastened to the shaft of a fan motor (not shown) and then the assembly of the fan hub 1 and fan blades 2 is mounted with the fan motor in a rack, constituting an electric fan for use in a cooler module for cooling a computer or any of a variety other electronic products.

Because the fan hub 1 and the fan blades 2 are separately molded from plastics and then assembled together, fan blades having different 3D camber and geometric shape features can be selectively used with one same fan hub to constitute different combination axial-flow fans for different applications to satisfy different cooling requirements, thereby lowering the mold cost. More particularly, as shown in FIGS. 4 and 5, because the fan blades 2 and the fan hub 1 are separately made and then assembled together, it is practical to constitute a high-performance axial-flow fan having low noise level, i.e., the front edge 21 of one fan blade 2 is suspending above the rear edge 22 of another adjacent fan blade 2 so that no gap is seen between each two adjacent fan blades 2 when the axial-flow fan is viewed from the front side (see FIG. 5), however the desired wind tunnel D is still maintained in between each two adjacent fan blades 2 (see FIG. 4). This fan structure is not achievable by conventional fan designs. By means of the application of the present invention, this fan structure is easily attainable.

Although a particular embodiment of the invention has been described in detail for purposes of illustration, various modifications and enhancements may be made without departing from the spirit and scope of the invention. Accordingly, the invention is not to be limited except as by the appended claims.

Claims

1. A combination axial-flow fan, comprising:

a fan hub, said fan hub comprising a center connection portion for the connection of a fan motor shaft and a plurality of mounting grooves equiangularly spaced around the periphery thereof, each said mounting groove having an open side disposed at a rear side of said fan hub; and

a plurality of fan blades, each said fan blade comprising a wedge block disposed at an inner end thereof insertable through the open side of one said mounting groove to secure the respective fan blade to said fan hub.

2. The combination axial-flow fan as claimed in claim 1, wherein each said mounting groove is a dovetail groove.

3. The combination axial-flow fan as claimed in claim 2, wherein the wedge block of each said fan blade is a dovetail block.