External fan

Abstract

An external fan is mounted on a chassis and includes a retaining stage and a ceramic axis. The retaining stage is arranged on one external side of the chassis and includes a base and a hollow rod erecting on the base. A stator is arranged outside the hollow rod. The ceramic axis passes into the hollow rod and includes a first end connected to a rotator wrapped outside the stator and a second end extending out of a bottom of the base and connected to a blade inside the chassis.

Description

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an improved external fan, and more particularly to an improved external fan suitable for operating external to a closed and high-temperature environment.

2. Description of Related Art

FIG. 1 shows an exploded view of a prior art fan structure, which is an external axial fan. The external axial fan comprises a hollow casing 1a with a rounded chamber 10a. A pivotal stage 11a is arranged on a bottom face of the rounded chamber 10a and a hollow rod 12a is projected from the center of pivotal stage 11a. A stator 2a is caped to the hollow rod 12a and is connected to a control circuit 20a. The stator 2a comprises a plurality of metal plates 21a stacked together and an induction coil 22a wrapped around the metal plates 21a. A rotator 3a comprises a hub 30a, a plurality of blades 31a and a magnet (not shown) arranged in the hub 30a. An axis (not shown) is arranged at center of the hub 30a and passes bearings 13a arranged in the hollow rod 12a such that the rotator 3a is placed in the rounded chamber 10a.

The fan is generally placed outside the working environment and blows cool air into the working environment and ejects hot air from the working environment to cool the working environment. However, for a closed working environment, an internal fan is also required to produce a convection effect for heat exchange between working environment and external ambience. The design of prior art fan is not suitable for high-temperature operation. The operation of fan will be unstable and the lifetime is limited for high-temperature operation. Moreover, the blade size is limited when the blades are fixed on the hub and the design of the blade is also limited.

SUMMARY OF THE INVENTION

The present invention provides an improved external fan suitable for operating external to a closed and high-temperature environment. The stator and the rotator of the fan are external to the high-temperature environment and the fan comprises a ceramic axis made of heat-resistant and durable material. Therefore the lifetime and stability of the fan can be ensured.

Accordingly, the present invention provides an external fan mounted on a chassis and including a retaining stage and a ceramic axis. The retaining stage is arranged on one external side of the chassis and includes a base and a hollow rod erecting on the base. A stator is arranged outside the hollow rod. The ceramic axis passes into the hollow rod and includes a first end connected to a rotator wrapped outside the stator and a second end extending out of a bottom of the base and connected to a blade inside the chassis.

BRIEF DESCRIPTION OF DRAWING

The features of the invention believed to be novel are set forth with particularity in the appended claims. The invention itself however may be best understood by reference to the following detailed description of the invention, which describes certain exemplary embodiments of the invention, taken in conjunction with the accompanying drawings in which:

FIG. 1 shows an exploded view of a prior art fan structure.

FIG. 2 shows an exploded view of the present invention.

FIG. 3 shows a perspective view of the present invention.

FIG. 4 is a sectional view of the present invention.

FIG. 5 shows an application of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

With reference to FIGS. 2 to 4, the present invention provides an improved external fan. As shown in FIG. 5, the external fan is mounted to a closed chassis of an electronic device during use and provides air convection for the closed chassis. The external fan comprises a retaining stage 1 and a ceramic axis 2.

The retaining stage 1 comprises a base 10 for assembling the retaining stage 1 and the base 10 comprises a plurality of flanges 100 on outer peripheral thereof. Moreover, each of the flanges 100 comprises a clamping hole 101 through which screwing units 50 are assembled. A hollow rod 11 is projected at center of the base 10 and through the center of the base 10. A stator 3 is provided outside the hollow rod 11 and is connected to a control circuit 32. The stator 3 comprises a plurality of metal plates 30 stacked together and an induction coil 31 wrapped around the metal plates 30. When the control circuit 32 supplies electrical current to the induction coil 31, the induction coil 31 excites magnetic field.

The ceramic axis 2 is resistant to high temperature and passes through the hollow rod 11. A plurality of bearings 20 is provided in the hollow rod 11 and caped to the ceramic axis 2. Both ends of the ceramic axis 2 expose out of the hollow rod 11 with one end connected to a rotator 4. The rotator 4 wraps outside the stator 3 and comprises a hub 40 and a magnetic unit 41 provided on inner face of the hub 40. The one end of the ceramic axis 2 is connected to bottom center of the hub 40; another end of the ceramic axis 2 extends out of a bottom of the retaining stage 1 and comprises a thread portion 21 for screwing to a blade 22. The blade 22 is made of material resistant to high temperature. The spiral direction of the thread portion 21 is opposite to the rotation direction of the rotator 4.

The external-rotation fan according to the present invention can be constructed by above-mentioned manner.

As shown in FIG. 5, the fan is mounted to a chassis 5 of an electronic device from external direction by engaging the flanges 100 into the chassis and screwing the screwing unit 50 (such as screw or bolt) into the clamping hole 101. Moreover, the ceramic axis 2 is inserted into the chassis and the blade 22 can be mounted on the ceramic axis 2 by the thread portion 21 subsequently. The blade 22 is operated for air convection inside the closed chassis, whereby the air inside the chassis 5 has sufficient heat exchange for heat dissipation.

The blade 22 is designed to separate with the hub 40. Therefore the blade 22 could have larger size. The shape of the blade 22 is not limited by the hub 40 because the blade 22 is extended from the ceramic axis 2 instead of the hub 40. The stator 3 and the rotator 4 of the fan are external to the chassis 5 and are exempted from high temperature in the chassis 5 during operation. Therefore the lifetime and stability of the fan can be ensured.

Although the present invention has been described with reference to the preferred embodiment thereof, it will be understood that the invention is not limited to the details thereof. Various substitutions and modifications have suggested in the foregoing description, and other will occur to those of ordinary skill in the art. Therefore, all such substitutions and modifications are intended to be embraced within the scope of the invention as defined in the appended claims.

Claims

1. An external fan mounted on a chassis, comprising:

a retaining stage arranged on one external side of the chassis and comprising a base and a hollow rod erecting on the base, a stator arranged outside the hollow rod; and

a ceramic axis passing into the hollow rod and comprising a first end connected to a rotator wrapped outside the stator and a second end extending out of a bottom of the base and connected to a blade inside the chassis.

2. The external fan as in claim 1, wherein the base comprises a plurality of flanges, each of the flanges comprises a clamping hole through which a screwing member is engaged.

3. The external fan as in claim 1, wherein the hollow rod comprises a plurality of bearings therein and capped on the ceramic axis.

4. The external fan as in claim 1, wherein the second end of the ceramic axis comprises a thread portion for screwing to the blade.

5. The external fan as in claim 4, wherein a spiral direction of the thread portion is opposite to a rotation direction of the rotator.

6. The external fan as in claim 1, wherein the blade is extended from a portion near the ceramic axis.