Patent Application
20060204387
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
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.
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.
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:
With reference to FIGS. 2 to 4, the present invention provides an improved external fan. As shown in
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
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.
