Fan Device

Description

CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority of Taiwanese Application No. 098143618, filed on Dec. 18, 2009.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention relates to a fan device, and more particularly to a fan device capable of producing enhanced air pressure.

2. Description of the Related Art

In order to enhance air pressure, a stator impeller is applied to a fan. The stator impeller is mounted to a fan housing of the fan, and includes a plurality of angularly equidistant stator blades. An air-guiding channel is formed between an adjacent pair of the stator blades. When a fan impeller of the fan is driven to rotate, air flowing from the air inlet is guided by the stator impeller to flow toward the fan impeller through the air-guiding channels, thereby enhancing air pressure produced by the fan. As a result, increased airflow amount can be attained. However, in such a configuration, greater acoustic noise occurs during rotation of the fan impeller at a speed within a certain speed range.

SUMMARY OF THE INVENTION

Therefore, an object of the present invention is to provide a fan device that can produce enhanced air pressure and increased airflow amount with reduced acoustic noise.

According to the present invention, a fan device comprises:

a fan housing configured with a receiving space and having a bottom wall formed with an air inlet in spatial communication with the receiving space, a top wall formed with an air outlet in spatial communication with the receiving space, and a surrounding side wall transverse to and interconnecting the top and bottom walls, and cooperating with the top and bottom walls to define the receiving space thereamong;

a fan impeller mounted in the receiving space in the fan housing, disposed adjacent to the air outlet in the top wall of the fan housing, and operable to rotate about a central axis that is transverse to the top and bottom walls of the fan housing; and

an air-guiding unit mounted fixedly in the receiving space in the fan housing and disposed adjacent to the air inlet in the bottom wall of the fan housing, the air-guiding unit including a center connecting member disposed coaxially with the central axis, and a plurality of air-guiding blades angularly spaced apart from each other and interconnecting the central connecting member and the surrounding side wall of the fan housing, an angular distance between each adjacent pair of the air-guiding blades being different from that of any other adjacent pair of the air-guiding blades.

BRIEF DESCRIPTION OF THE DRAWINGS

Other features and advantages of the present invention will become apparent in the following detailed description of the preferred embodiments with reference to the accompanying drawings, of which:

FIG. 1 is a schematic bottom view showing the first preferred embodiment of a fan device according to the present invention;

FIG. 2 is a perspective view showing the first preferred embodiment without a fan impeller;

FIG. 3 is a partly schematic sectional view showing the first preferred embodiment;

FIG. 4 is a plot illustrating experimental measurement results of acoustic noise generated by the prior art and the first preferred embodiment;

FIG. 5 is a schematic top view showing the second preferred embodiment of a fan device according to the present invention without a fan impeller;

FIG. 6 is a schematic top view showing a variation of the second preferred embodiment; and

FIG. 7 is a schematic top view showing the third preferred embodiment of a fan device according to the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Before the present invention is described in greater detail, it should be noted that like elements are denoted by the same reference numerals throughout the disclosure.

Referring to FIGS. 1 to 3, the first preferred embodiment of a fan device according to the present invention is shown to include a fan housing 1, a fan impeller 2, and an air-guiding unit 3.

The fan housing 1 is configured with a receiving space 10, and has a bottom wall 11, a top wall 12 and a surrounding side wall 13. The bottom wall 11 is formed with an air inlet 111 in spatial communication with the receiving space 10. The top wall 12 is formed with an air outlet 121 in spatial communication with the receiving space 10. The surrounding side wall 13 is transverse to and interconnects the top and bottom walls 12, 11, and cooperates with the top and bottom walls 12, 11 to define the receiving space 10 thereamong.

The fan impeller 2 is mounted in the receiving space 10 in the fan housing 1, is disposed adjacent to the air outlet 121 in the top wall 12 of the fan housing 1, and is operable to rotate about a central axis (X) that is transverse to the top and bottom walls 12, 11 of the fan housing 1. In this embodiment, the fan impeller 2 includes a hub body 21, and a plurality of fan blades 22 extending outwardly and radially from the hub body 21. In this embodiment, the fan blades 22 are angularly equidistant.

The air-guiding unit 3 is mounted fixedly in the receiving space 10 in the fan housing 1, and is disposed adjacent to the air inlet 111 in the bottom wall 11 of the fan housing 1. The air-guiding unit 3 includes a center connecting member 31 disposed coaxially with the central axis (X), and a plurality of air-guiding blades angularly spaced apart from each other and interconnecting the central connecting member 31 and the surrounding side wall 13 of the fan housing 1. An angular distance (θ) between each adjacent pair of the air-guiding blades 32 is different from that of any other adjacent pair of the air-guiding blades 32. In this embodiment, the center connecting member 31 includes a circular cap body 312, and a tube body 311 extending integrally from the cap body 312 toward the hub body 21 and disposed coaxially with the central axis (X).

In operation, when the fan impeller 2 is driven to rotate, air flowing from the air inlet 111 is guided by the air-guiding blades 32, and then flows toward the air outlet 121, as indicated by solid-line arrows in FIG. 3.

In sum, due to the presence of the air-guiding unit 3, the fan device of the present invention can produce enhanced air pressure, thereby resulting in increased airflow amount. It is noted that, since the angular distances (θ) are different from each other, the fan device of the present invention generates reduced acoustic noise during operation as compared to the prior art, as shown in FIG. 4.

FIG. 5 illustrates the second preferred embodiment of a fan device according to this invention, which is a modification of the first preferred embodiment. Unlike the first preferred embodiment, the air-guiding unit 3′ further includes a plurality of auxiliary air-guiding blades 33 extending inwardly and radially from the surrounding side wall 13 of the fan housing toward the central connecting member 31. Each auxiliary air-guiding blade 33 is disposed between a corresponding adjacent pair of the air-guiding blades 32, and is spaced apart from the corresponding adjacent pair of the air-guiding blades 32 and the central connecting member 31. In this embodiment, the auxiliary air-guiding blades 33 have the same length.

FIG. 6 illustrates a variation of the second preferred embodiment, wherein each of the auxiliary air-guiding blades 33 of the air-guiding unit 3′ has a length different from that of any other one of the auxiliary air-guiding blades 33.

FIG. 7 illustrates the third preferred embodiment of a fan device according to this invention, which is a modification of the first preferred embodiment. Unlike the first preferred embodiment, an angular distance (Φ) between each adjacent pair of the fan blades 22 is different from that of any other adjacent pair of the fan blades 22.

While the present invention has been described in connection with what are considered the most practical and preferred embodiments, it is understood that this invention is not limited to the disclosed embodiments but is intended to cover various arrangements included within the spirit and scope of the broadest interpretation so as to encompass all such modifications and equivalent arrangements.