FAN

Abstract

A fan includes a frame and an impeller. The frame defines a hole in a middle of the frame. An inner wall of the frame bounding the hole defines a circumferential groove and forms a circumferential protrusion adjoining the groove. The impeller is received in the hole of the frame. When the impeller is rotated, airflow through the hole is pressurized by the groove and the protrusion, and concentrates when the airflow is blown out of the hole.

Description

BACKGROUND

1. Technical Field

The present disclosure relates to a fan.

2. Description of Related Art

FIG. 1 shows a typical fan 80 comprising a frame 81 and an impeller 83. A circular hole 85 is defined in a middle of the frame 81, for receiving the impeller 83. An inner surface of the frame 81 bounding the hole 85 is smooth. When the impeller 83 is rotated, air is drawn into the hole 85 from a side of the fan 80, and a considerable amount of air is radially flown out of the hole 85 from an opposite side of the fan 80. Thereby, the fan 80 may not effectively dissipate heat for some devices which need heat dissipation by more concentrated air.

BRIEF DESCRIPTION OF THE DRAWINGS

Many aspects of the present embodiments can be better understood with reference to the following drawings. The components in the drawings are not necessarily drawn to scale, the emphasis instead being placed upon clearly illustrating the principles of the present embodiments. Moreover, in the drawings, all the views are schematic, and like reference numerals designate corresponding parts throughout the several views.

FIG. 1 is a plan, sketch view of a conventional fan in use.

FIG. 2 is an assembled, isometric view of an embodiment of a fan.

FIG. 3 is a plan, sketch view of the fan of FIG. 2 in use.

DETAILED DESCRIPTION

The disclosure, including the accompanying drawings, is illustrated by way of example and not by way of limitation. It should be noted that references to “an” or “one” embodiment in this disclosure are not necessarily to the same embodiment, and such references can mean “at least one.”

FIGS. 2 and 3 show an exemplary embodiment of a fan 10 comprising a frame 12 and an impeller 14.

The frame 12 comprises two opposite sidewalls 121. A hole 123 having an elliptic cross section is defined in a middle of the frame 12, extending through the sidewalls 121. The impeller 14 is mounted in the hole 123. A plurality of circumferential grooves 125 is defined in an inner wall 124 of the frame 12 bounding the hole 123, such that two circumferential protrusions 126 are formed on the inner wall 124 adjoining opposite sides of each groove 125. In the embodiment, a cross section of each groove 125 and each protrusion 126 is arc-shaped, such that the grooves 125 and the protrusions 126 cooperate to form a wave-shaped surface on the inner wall 124 of the frame 12.

In use, the impeller 14 is rotated, airflow is drawn into the hole 123 from an end of the hole 123, and is blown out of the hole 123 from an opposite end of the hole 123. Because the spaced grooves 125 and protrusions 126 are formed on the inner wall 124 bounding the hole 123, the airflow through the hole 123 is pressurized by the grooves 125 and the protrusions 126, and concentrates when the airflow is blown out of the hole 123. Thereby, the fan 10 can provide stronger, concentrated airflow.

In the embodiment, a cross section of the hole 123 is elliptic, which can reduce wind noise.

In other embodiments, the inner wall 124 can define only one circumferential groove 125 and form only one circumferential protrusion 126 adjoining the groove 125.

Even though numerous characteristics and advantages of the embodiments have been set forth in the foregoing description, together with details of the structure and the functions of the embodiments, the disclosure is illustrative only, and changes may be made in details, especially in the matters of shape, size, and arrangement of parts within the principles of the embodiments to the full extent indicated by the broad general meaning of the terms in which the appended claims are expressed.

Claims

1. A fan, comprising:

a frame defining a hole in a middle of the frame, an inner wall of the frame bounding the hole defining a circumferential groove and forming a circumferential protrusion adjoining the groove; and

an impeller received in the hole of the frame, wherein when the impeller is rotated, airflow through the hole is pressurized by the groove and the protrusion, and concentrates when the airflow is blown out of the hole.

2. The fan of claim 1, wherein the groove and the protrusion cooperate to form a wave-shaped surface on the inner wall of the frame.

3. The fan of claim 2, wherein a cross section of each of the groove and the protrusion is arc-shaped.

4. The fan of claim 1, wherein a cross section of the hole is elliptic.

5. A fan, comprising:

a frame defining a hole in a middle of the frame, an inner wall of the frame bounding the hole defining a plurality of circumferential grooves and forming two circumferential protrusions adjoining opposite sides of each groove; and

an impeller received in the hole of the frame, wherein when the impeller is rotated, airflow through the hole is pressurized by the plurality of grooves and protrusions, and concentrates when the airflow is blown out of the hole.

6. The fan of claim 5, wherein the plurality of grooves and protrusions cooperate to form a wave-shaped surface on the inner wall of the frame.

7. The fan of claim 6, wherein a cross section of each groove and each protrusion is arc-shaped.

8. The fan of claim 5, wherein a cross section of the hole is elliptic.