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Cooling fan

Cooling fan description/claims

1. Field of the Invention

The present invention relates to a cooling fan, and more particularly relates to a cooling fan having an improved bearing assembly.

2. Description of Related Art

With the continuing development of the electronic technology, electronic packages such as CPUs (central processing units) are generating more and more heat that requires immediate dissipation. Cooling fans are commonly used in combination with heat sinks for cooling CPUs.

Oftentimes, a cooling fan includes a blade set and a fan seat. The fan seat has a central tube portion integrally formed thereon. A pair of sleeve bearings are arranged in the tube portion. A coil is wound around the outside of the tube portion. The blade set is formed with a cap and fan blades connecting to the cap. A stainless steel rotary shaft supported by the pair of sleeve bearings at two opposite ends thereof is arranged within the cap. A magnet pushed by magnetic force of the coil is fixed to the cap and is driven to rotate by the coil so that the fan blades can produce an airflow. Since the aforesaid stainless steel rotary shaft is arranged on the sleeve bearings to rotate, after rotating for a period of time, the rotary shaft and the bearings will experience wear due to leaking of lubricating oil contained therebetween. Thus, the lifetime of the fan will be reduced. In order to improve the lifetime of the fan, wear-tolerable ball bearings for point contact have been developed. However, the manufacturing process for ball bearings requires precision-grinding and a high polish, and thus the ball bearings are more expensive, which results in higher expense.

For the foregoing reasons, therefore, there is a need in the art for a cooling fan which overcomes the above-mentioned problems.

According to a preferred embodiment of the present invention, a cooling fan includes a fan housing having an upper tube extending downwardly from a top side thereof and a lower tube extending upwardly from a bottom side thereof, a ball bearing being mounted in the upper tube, a sleeve bearing being mounted in the lower tube, a stator mounted around the lower tube, and a rotor. The rotor includes a hub located between the ball bearing and the sleeve bearing, and a shaft extending through the hub. Two ends of the shaft are rotatably received in the ball bearing and the sleeve bearing, respectively.

Other advantages and novel features of the present invention will be drawn from the following detailed description of the preferred embodiments of the present invention with attached drawings, in which:

Many aspects of the present cooling fan 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 cooling fan. Moreover, in the drawings, like reference numerals designate corresponding parts throughout the several views.

FIG. 1 is an isometric, exploded view of a cooling fan in accordance with a preferred embodiment of the present invention;

FIG. 2 is an exploded view of the cooling fan of FIG. 1 viewed from another aspect;

FIG. 3 is an assembled view of the cooling fan of FIG. 1; and

FIG. 4 is a cross sectional view of the cooling fan taken from line IV-IV of FIG. 3.

• Provisional Patent
• Utility Patent

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