Pumps – Motor driven – Including means for facilitating assembly or disassembly of...
Reexamination Certificate
2000-09-27
2003-11-25
Robinson, Daniel (Department: 3742)
Pumps
Motor driven
Including means for facilitating assembly or disassembly of...
Reexamination Certificate
active
06652246
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention relates to a centrifugal fan having an upside-down mounted structure, and more particularly to a centrifugal fan having an upside-down mounted structure so as to possess a relatively long service life.
2. Description of the Related Art
Recently, electrical products tend to be smaller and thinner than ever. Notebook computers as described below for example, are getting thinner and thinner. A heat-dissipating device for a notebook computer includes a fan and a heat-dissipating plate for dissipating the heat energy generated during the computer operation. Therefore, the development of a relatively thin heat-dissipating device is in demand for a relatively thin notebook computer.
FIG. 4A
is a top view of a conventional heat-dissipating device, and
FIG. 4B
is a front view of FIG.
4
A. Referring to
FIG. 4A
, the heat-dissipating device includes an axial-flow fan
100
and a heat-dissipating plate
200
. The axial-flow fan
100
includes a motor (not shown), a frame
101
, and an axial-flow type of impeller
104
. The motor used for driving purpose has a printed circuit board (not shown) positioned at its bottom, and the frame has four ribs
102
and an outlet
103
while the axial-flow impeller
104
has a hub
105
and a plurality of blades
106
. In addition, a plurality of fins
201
and passages
202
are formed on the heat-dissipating plate
200
for dissipating heat.
Because the heat-dissipating device must be made relatively thin, the prior art in which the axial-flow fan
100
is directly mounted above the fins
201
cannot be adopted in a notebook computer or other similar electric products due to the limited thickness.
Referring to
FIG. 4B
, the heat-dissipating plate
200
is in L-shape and the axial-flow fan
100
is mounted on the right side surface of the heat-dissipating plate
200
. When the axial-flow fan
100
rotates, the air is sucked in on one side and blown out on the other side, and the arrowheads indicate the direction of airflow. That is, the air flows from the topside of the axial-flow fan
100
into the axial-flow fan
100
, and then, it flows from the frame
101
to the passages
202
of the heat-dissipating plate
200
to achieve the function of heat-dissipation.
The axial-flow fan of the prior art cannot provide relatively high air pressure either. The heat dissipating effect is relatively poor due to the interference of the plurality of fins
201
. In addition, it is also due to the fact that the printed circuit board at the bottom of the motor is positioned close to the heat-dissipating plate
200
or even in direct contact with the heat-dissipating plate
200
. In general, the temperature of the heat-dissipating plate
200
is much higher than that of the fan in operation. In this case, the relatively high temperature of the heat-dissipating plate
200
will shorten the service life of the fan.
FIG. 5A
is a top view of a conventional heat-dissipating device, and
FIG. 5B
is a front view of FIG.
5
A. Referring now to
FIG. 5A
, the heat-dissipating device includes an axial-flow fan without frames, and a heat-dissipating plate
400
. The axial-flow fan includes a motor (not shown), a base
301
, and an axial-flow impeller
304
. The motor has a printed circuit board (not shown) at its bottom while the axial-flow impeller
304
has a hub
305
and a plurality of blades
306
. The heat-dissipating plate
400
includes a plurality of fins
401
, a fan seat
403
, and an outlet
404
. The plurality of fins
401
are used for dissipating heat, and the fan seat
403
is for receiving the axial-flow fan and providing flow ducts of the frameless type. And the outlet
404
is formed on the side surface of the fan seat
403
for the air to flow into the passage
402
.
Referring to
FIG. 5B
, the axial-flow fan
300
is mounted inside the fan seat
403
of the heat-dissipating plate
400
. The axial-flow fan
300
sucks the air into the fan seat
403
and discharges the air therefrom. The arrowheads indicate the direction of the airflow. That is, the air flows into the axial fan from the topside thereof, it then flows through the passage
402
of the heat-dissipating plate
400
and the outlet
404
to achieve the function of heat-dissipating.
The axial-flow fan of the above-mentioned prior art cannot provide a relatively high air pressure either. This is because that under the blocking effect of the plurality of fins
401
, a relatively good radiation effect cannot be obtained.
In addition, the printed circuit board located under the motor is positioned close to or in direct contact with the heat-dissipating plate
400
. In general, the temperature of the heat-dissipating plate
400
is higher than the temperature of the fan in operation. Therefore, the high temperature of the heat-dissipating plate
400
may shorten the service life of the fan. Furthermore, the heat-dissipating plate
400
of axial-flow fan applicable for using the frame-less type can not control the airflow produced by the axial-flow fan without the fan seat
403
. The fan seat
403
, the fins
401
, and the passages
402
are integrally formed, and all of them are generally made of aluminum material. In case that the fan seat
403
is integrally formed with the axial-flow fan
300
, it is preferable that both the fan seat
403
and the axial-flow fan
300
are made of plastic material that has a lower density than that of the aluminum material. Therefore, in comparison with the heat-dissipating device as shown in
FIG. 4A
, the weight of the heat-dissipating device as shown in
FIG. 5A
is increased further.
SUMMARY OF THE INVENTION
It is therefore one of the object of the invention to provide a centrifugal fan having an upside-down mounted structure capable of preventing the electric elements of the fan from being affected by the heat-dissipating plate with relatively high temperature in order to increase its service life. In addition, the centrifugal fan can also provide a better radiation effect than that of the conventional axial-flow fan.
In accordance with one embodiment of the invention, a centrifugal fan having an upside-down mounted structure is mounted on a heat-dissipating plate. The centrifugal fan includes a frame fixed on the heat dissipating plate and a stator upside-down mounted in the frame and fixed on the upper surface. The frame includes an upper surface positioned away from the heat-dissipating plate, a side surface substantially perpendicular to the upper surface, at least one inlet formed on the upper surface, and an outlet formed on the side surface. The stator includes a printed circuit board positioned close to the upper surface and positioned away from the heat-dissipating plate.
The frame may further includes a bearing seat connected to the upper surface of the frame and at least one rib formed on the upper surface of the frame for fixing the bearing seat. The at least one inlet is defined by the upper surface of the frame and the at least one rib.
It is preferable that the centrifugal fan having an upside-down mounted structure further includes a centrifugal impeller enclosing the stator and capable of rotating with respect to the stator. The centrifugal impeller includes a hub and a plurality of blades connected to the hub to form a plurality of connection portions positioned close to the heat-dissipating plate and positioned away from the upper surface of the frame.
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patent
Huang Wen-shi
Huang Yu-huang
Lin Kuo-cheng
Tsai Ming-shi
Delta Electronics , Inc.
Martine & Penilla LLP
Robinson Daniel
LandOfFree
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