Pumps – Motor driven – Electric or magnetic motor
Reexamination Certificate
2000-05-04
2001-10-30
Freay, Charles G. (Department: 3746)
Pumps
Motor driven
Electric or magnetic motor
Reexamination Certificate
active
06309191
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to the art fan and more particularly to a direct-current brushless fan with improved features.
BACKGROUND OF THE INVENTION
The manufacturing techniques of direct-current brushless motor and fan are well-known. Direct-current brushless fan are widely employed in a variety of fields particularly as cooling fan due to low power consumption, low noise, and durability. As such, effort to maintain and further improve such advantages is still desirable.
Conventionally, the smoothness of direct-current brushless motor in rotation is adjusted by manufacturing worker. However, most workers just perform required operations in assembling the work without a sufficient experience to install rotor in a position with respect to stator for obtaining an optimum magnetization. As such, fan may not operate smoothly due to slantingly configured components. A few manufacturers have noticed such problem. However, no document has disclosed techniques to easily assemble rotor and stator in above optimum position.
A conventional technique aiming at eliminating above problem is disclosed. It places washer in shaft housing to adjust the position of rotor with respect to stator. However, the previous design suffered from several disadvantages: 1) Friction may increase due to the insertion of washer which in turn generates noise. An improvement is to fill lubricating oil into shaft housing to reduce friction. But the volumn of oil reservoir is thus decreased. Further, lubricating oil may spill out of shaft housing in operation: 2) Retaining ring is usually employed to secure the end of shaft. Accordingly, retaining ring may rotate when shaft rotates. As such, high friction resistance must exist between retaining ring and shaft in rotation which in turn adversely affects the smoothness of rotation as well as generates noise. Moreover, a rotational resistance to fan still exists in the oil reservoir due to the rotation of retaining ring.
Thus, it is desirable to provide a brushless fan in order to overcome the above drawbacks of prior art.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide a brushless fan having the features of smooth rotation, stability, no slanting configured component, very low noise, and excellent lubrication.
It is another object of the present invention to provide a brushless fan having a larger lubricating oil storage space and without the provision of washer.
To achieve the above and other objects, the present invention provides a brushless comprising a variety of features. In detail, within the shaft housing, a first slope near bottom is tapered toward the bottom of shaft housing for supporting bearing. At the external surface, a second slope is tapered from above the bottom of base toward shaft housing for supporting stator assembly. As such, bearing and stator assembly can precisely position with respect to shaft housing for obtaining an optimum magnetization, whereby shaft is able to stably rotate under the influence of magnetic field of rotor. Lubricating oil reservoir is provided between bearing and the top of shaft housing. Oil ring and projected cylindrical member are provided on top of shaft housing being oblique with respect to each other and separated by a minimum gap, thereby sealing the oil reservoir. With this minimum gap, lubricating oil is effectively prevented from spilling when cylindrical housing is rotating. Further, a larger oil storage space and the omission of washer are effected. Finally, retaining ring is secured to the bottom of shaft housing. Outer diameter of retaining ring conforms to inner diameter of shaft housing, while inner diameter of retaining ring is slightly larger than outer diameter of groove of shaft. With this, retaining ring may not rotate when shaft rotates. Thus no frictional resistance exists between friction and other element and in lubricating oil. Also, a very low noise is generated. Most importantly, the performance of fan is improved.
The above and other objects, features and advantages of the present invention will become apparent from the following detailed description taken with the accompanying drawings.
REFERENCES:
patent: 4861237 (1989-08-01), Shiraki et al.
patent: 5997265 (1999-12-01), Chung
patent: 6050785 (2000-04-01), Horng
patent: 6183221 (2001-02-01), Hsieh
Freay Charles G.
Pro-Techtor Inter-national Services
Rodriguez William H
Tranyoung Technology Corp.
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