Combination fan blade unit for electric fan

Abstract

A combination fan blade unit includes a fan hub defining an installation chamber and an axle hole in the installation chamber, a plurality of blower blades radially equiangularly arranged on the top sidewall of the fan hub, and a plurality of axial-flow blades radially equiangularly arranged around the peripheral wall of the fan hub.

Description

BACKGROUND OF THE INVENTION

[0001] The present invention relates to an electric fan and, more specifically, to a combination fan, which produces a big amount of wind when operated.

[0002] An axial-flow fan is generally comprised of a fan motor, and a fan blade unit. The fan blade unit 12 comprises a fan hub 19, and a plurality of blades 18 equiangularly spaced around the periphery 20 of the fan hub 19 (see FIG. 2). The detailed axial-flow fan structure 10, as shown in FIG. 1, comprises a housing 11, a fan blade unit 12, a circuit board 13, a coil 14, a permanent magnet 15, an axle bearing 16, and a shaft 17. When connecting electricity to the coil 14, an electric magnetic field is produced and acted with the magnetic field of the permanent magnet 15, causing electric energy to be turned into dynamic energy to rotate the fan unit 12. Because this structure of axial-flow fan is of the known art, no further detailed description is necessary.

[0003] Conventional axial-flow fans are commonly used for cooling computers CPU and AC adapter and other industrial products. In order to improve cooling and heat dissipation efficiency, the most direct and effective way is to increase the amount of wind. Increasing the amount of wind can be achieved by different measures, for example, increasing the revolving speed of the fan motor or changing the design of the fan blade unit.

[0004] Increasing the revolving speed of the fan motor relatively increases the amount of wind, therefore the cooling and heat dissipation effective is relatively improved. However, increasing the revolving speed of the fan motor causes the axle bearing to wear quickly. The heat produced due to friction between the shaft and the axle bearing causes the axle bearing to be damaged quickly, resulting in short service life of the axial-flow fan. Keeping the fan blade in balance is another important factor to be taken into account when wishing to increase the amount of wind by increasing the revolving speed of the fan motor. If the blades of the fan blade unit are not arranged in balance, the blades will vibrate when starting the axial-flow fan, affecting the axial-flow fan quality and its service life. Therefore, it is not a good measure to increase the amount of wind simply by increasing the revolving speed of the fan motor. Further, increasing the revolving speed of the fan motor also results in waste of power and increase of heat. Therefore, the best way to increase the amount of wind is to change the design of the fan blade unit.

SUMMARY OF THE INVENTION

[0005] The present invention has been accomplished under the circumstances in view. It is one object of the present invention to provide a combination fan blade unit for electric fan, which produces a big amount of wind to achieve a high cooling and heat dissipation effect.

[0006] It is another object of the present invention to provide a combination fan blade unit for electric fan, which reduces wearing of the axle bearing of the fan and the production of heat during the operation of the fan.

[0007] According to one embodiment of the present invention, the combination fan blade unit comprises a fan hub defining an installation chamber and an axle hole in the installation chamber, a plurality of blower blades radially equiangularly arranged on the top sidewall of the fan hub, and a plurality of axial-flow blades radially equiangularly arranged around the peripheral wall of the fan hub.

[0008] According to another embodiment of the present invention, the combination fan blade unit comprises a fan hub defining an installation chamber and an axle hole in the installation chamber, a plurality of blower blades radially equiangularly arranged on the top sidewall of the fan hub, and two sets of axial-flow blades alternatively arranged around the peripheral wall of the fan hub at different elevations.

BRIEF DESCRIPTIONN OF THE DRAWINGS

[0009] FIG. 1 is a sectional view of an axial-flow fan according to the prior art.

[0010] FIG. 2 is an elevational view of a fan blade unit for an axial-flow fan according to the prior art.

[0011] FIG. 3 is an oblique elevation of a fan blade unit for an axial-flow fan according to the present invention.

[0012] FIG. 4 is a top view of the fan blade unit according to the present invention.

[0013] FIG. 5 is a longitudinal view in section of the fan blade unit according to the present invention.

[0014] FIG. 6 is a sectional view showing the fan blade unit installed in an axial-flow fan according to the present invention.

[0015] FIG. 7 is an oblique elevation of an alternate form of the fan blade unit according to the present invention.

[0016] FIG. 8 is a top view of the fan blade unit shown in FIG. 7.

[0017] FIG. 9 is a longitudinal view in section of the fan blade unit shown in FIG. 7.

[0018] FIG. 10 is a sectional view showing the fan blade unit of FIG. 7 installed in an axial-flow fan.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

[0019] Referring to FIGS. from 3 through 6, a combination fan blade unit 32 is shown comprising a fan hub 39. The fan hub 39 comprises a circular top wall 40, and a peripheral wall 41 downwardly extended from the border of the circular top wall 40. The top wall 40 and the peripheral wall 41 define an installation chamber 42 adapted to receive the component parts of an axial-flow fan 30 including a permanent magnet 35, a coil 34, and a circuit board 33 (see FIG. 6, the reference sign 31 indicates a housing). The installation chamber 42 comprises an axle hole 43, which receives one end of the shaft, referenced by 37. The other end of the shaft 37 is inserted through an axle bearing 36 to support rotation of the fan blade unit 32. Blower blades 44 are radially equiangularly arranged on the top wall 40 of the fan hub 39. Axial-flow blades 45 are radially equiangularly arranged around the peripheral wall 41 of the fan hub 39. During rotary motion of the fan unit 32 in the axial-flow fan 30, the blower blades 44 draw currents of air from the topside vertically downwardly toward the axial-flow blades 45, enabling the axial-flow blades 45 to send out currents of air. By means of the action of the blower blades 44 and the axial-flow blades 45, a big amount of wind is produced to achieve a high cooling and heat dissipation effect without producing much noise and heat. Therefore, in comparison with prior art designs, the revolving speed of the motor can be relatively reduced to achieve same output.

[0020] FIGS. from 7 through 9 show an alternate form of the present invention. According to this alternate form, the fan blade unit 52 comprises a fan hub 59. The fan hub 59 comprises a circular top wall 60, and a peripheral wall 61 downwardly extended from the border of the circular top wall 60. The top wall 60 and the peripheral wall 61 define an installation chamber 62 adapted to receive the component parts of an axial-flow fan 50 including a permanent magnet 55, a coil 54, and a circuit board 53 (see FIG. 10, the reference sign 51 indicates a housing). The installation chamber 62 comprises an axle hole 63, which receives one end of the shaft, referenced by 57. The other end of the shaft 57 is inserted through an axle bearing 56 to support rotation of the fan blade unit 52. Further, two sets of axial-flow blades 64 and 65 are alternatively arranged around the peripheral wall 61 of the fan hub 59 at different elevations. This alternate form achieves the following advantages:

[0021] 1. Increasing the number of blades in a limited space;

[0022] 2. Increasing the number of wind-cut holes 66 and wind outlets 67 so as to increase the amount of wind and improve the cooling and heat dissipation effect; and

[0023] 3. Increasing the wind pressure without changing the wind output angle and the position of the wind outlets.

[0024] As indicated above, the fan blade units 32 and 52 achieve the effect of producing a big amount of wind, enabling the axial-flow fans 30 and 50 to provide sufficient amount of wind for cooling and heat dissipation purpose without increasing the revolving speed of the fan motor. With respect axle bearing service life, it is calculated subject to JIS as follows: 1 L = 10 60 N ( c p ) ( hr )

[0025] in which, N=revolving speed (RPM: Revolution Per Minute);

[0026] C=development rated load (Kgf);

[0027] P=load at axle bearing (Kgf).

[0028] According to the aforesaid equation, when the conditions of P and C remained unchanged, the service life of the axle bearing (fan) is indirectly proportional to the revolving speed. Because the invention can produce same amount of wind at a relatively lower revolving speed, less friction is produced between the shaft and the axle bearing and less noise and heat is produced during the operation of the fan according to the present invention. Therefore, the invention greatly extends the service life of the fan.

[0029] It is to be understood that the drawings are designed for purposes of illustration only, and are not intended for use as a definition of the limits and scope of the invention disclosed. For example, blower blades may be radially equiangularly provided at the circular top wall 60 of the fan blade unit 52 of the embodiment shown in FIG. 7.

Claims

What the invention claimed is:

1. A combination fan blade unit comprising a fan hub, said fan hub comprising a circular top wall, and a peripheral wall extended from the border of said circular top wall and defining with said circular top wall an installation chamber and an axle hole in said installation chamber, a plurality of blower blades radially equiangularly arranged on said circular top wall, and a plurality of axial-flow blades radially equiangularly arranged around said peripheral wall of said fan hub.

2. A combination fan blade unit comprising a fan hub, said fan hub comprising a circular top wall, and a peripheral wall extended from the border of said circular top wall and defining with said circular top wall an installation chamber and an axle hole in said installation chamber, and two sets of axial-flow blades alternatively arranged around said peripheral wall of said fan hub at different elevations.

3. The combination fan blade unit of claim 2 further comprising a plurality of blower blades radially equiangularly arranged on said circular top wall.