BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a heat dissipating fan, and more particularly to a non-contact dust-proof structure of a heat dissipating fan.
2. Description of the Prior Art
A heat dissipating fan is used to dissipate heat for electronic apparatus or component, such as CPU, display card or power supply. A conventional heat dissipating fan comprises a stator and a rotor. An oil-retaining bearing is provided in an axial hole of a shaft of the stator. The stator has an electromagnetic coil and a silicon steel plate fixed on the shaft. The rotor has an axle inserted in the oil-retaining bearing and a permanent magnet ring fitted on the electromagnetic coil. When the fan is started, the electromagnetic coil and the magnet ring will generate a magnetic field to drive the rotor to turn around the shaft. Blades on the rotor are turned to bring air current to dissipate the heat generated from the electronic component so as to lower the temperature of the electronic component.
Even though the traditional fan structure has the basic function to dissipate heat, its structure and function still have some shortcomings. Particularly, there is a gap between the hub of the rotor and the base of the stator as well as between the top edge of the shaft and the bottom surface of the hub of the rotor. The external dust may enter the fan through the gap. After a period of time, the dust or water accumulated in the fan will influence the running of the fan and its service life. Especially, when the dust or water enters the oil-retaining bearing, the fan won't run smoothly or work.
SUMMARY OF THE INVENTION
The present invention is to provide a non-contact dust-proof structure of a heat dissipating fan to overcome the shortcomings existing in the prior art.
According to the present invention, there is provided a structure of a heat dissipating fan, comprising a stator and a rotor, a bearing being fixed in an axial hole of a shaft of the stator, the rotor having an axle which is inserted in the bearing, characterized by that: the rotor further comprising an axle base disposed at a distal end of the axle, the axle base being inserted in the axial hole of the shaft, a gap being defined between an outer surface of the axle base and an inner surface of the axial hole, the outer surface of the axle base being formed with a plurality of air guiding grooves adapted to exhaust the air in the bearing.
Preferably, the air guiding grooves are spiral grooves.
Preferably, the air guiding grooves are V-like grooves which include a first groove and a second groove, the first groove is adapted to compress the air in the axial hole inward, the second groove is adapted to exhaust the air, the first groove and the second groove are obliquely formed on the outer surface of the axle base, and tail ends of the first groove and the second groove are interconnected
According to a preferred embodiment of invention, the distal end of the axle is provided with the axle base and the outer surface of the axle base is formed with the air guiding grooves. When the rotor is turned at a high speed, the air guiding grooves will preferably form an exhaust effect, achieving a non-contact dust-proof protection structure to block external dust or water from entering the bearing in the axial hole, so that the running of the bearing will not be influenced. The present makes it possible that the heat dissipating fan has a better function and a longer service life.
BRIEF DESCRIPTION OF THE DRAWINGS
- Fig. 1 is a cross-sectional view according to a preferred embodiment of the present invention;
- Fig. 2 is an enlarged view showing the axle and the axle base having spiral grooves according to the preferred embodiment of the present invention; and
- Fig. 3 is an enlarged view showing the axle and the axle base having V-like grooves according to the preferred embodiment of the present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Embodiments of the present invention will now be described, by way of example only, with reference to the accompanying drawings.
As shown in Fig. 1, a non-contact dust-proof structure of a heat dissipating fan according to a preferred embodiment of the present invention comprises a stator 10 and a rotor 20. A bearing 13 is fixed in an axial hole 12 of a shaft 11 of the stator 10. The rotor 20 has an axle 21 which is inserted in the bearing 13.
In particular, the rotor 20 further comprises an axle base 22 disposed at a distal end of the axle 21. The axle base 22 is inserted in the axial hole 12 of the shaft 11. A gap is defined between an outer surface of the axle base 22 and an inner surface of the axial hole 12. The outer surface of the axle base 22 is formed with a plurality of air guiding grooves 23 adapted to exhaust the air in the bearing 13.
As shown in Fig. 2, the air guiding grooves 23 are in the form of spiral grooves. When the rotor 20 is turned at a high speed, the air in the axial hole 12 of the shaft 11 will be exhausted through the spiral grooves, such that negative pressure is formed in the axial hole 12 to block external dust or water from entering the bearing 13 in the axial hole 12.
As shown in Fig. 3, the air guiding grooves 23 are in the form of V-like grooves which include a first groove 231 and a second groove 232. The first groove 231 and the second groove 232 are obliquely formed on the outer surface of the axle base 22, and tail ends of the first groove 231 and the second groove 232 are interconnected. The first groove 231 is adapted to compress the air in the axial hole 12 inward and the second groove 232 is adapted to exhaust the air, such that lower pressure air is formed at the junction of the first groove 231 and the second groove 232 to block external dust or water from entering the bearing 13 in the axial hole 12.
The feature of the present invention is that the distal end of the axle is provided with the axle base and the outer surface of the axle base is formed with the air guiding grooves. When the rotor is turned at a high speed, the air guiding grooves will form an exhaust effect, achieving a non-contact dust-proof protection structure to block external dust or water from entering the bearing in the axial hole, so that the running of the bearing won't be influenced. The present invention ensures that the heat dissipating fan has a better function and a longer service life.
Although particular embodiments of the present invention have been described in detail for purposes of illustration, various modifications and enhancements may be made without departing from the spirit and scope of the present invention. Accordingly, the present invention is not to be limited except as by the appended claims.