Electrical generator or motor structure – Dynamoelectric – Rotary
Reexamination Certificate
2001-05-24
2004-03-30
Le, Dang (Department: 2834)
Electrical generator or motor structure
Dynamoelectric
Rotary
C310S090000, C310S089000, C310S254100
Reexamination Certificate
active
06713907
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an improvement of a blower for use in a variety of office automation equipments (hereinafter referred to as OA equipment)
2. Description of Related Art
An OA equipment such as a computer or a copying machine, etc. houses electronic circuits (a multiplicity of electronic parts) in its housing, which generates a considerable amount of heat causing a damage or a deterioration of the electronic parts because the heat is not easily released from the housing.
In particular, such OA equipment in recent years is in a downsizing trend providing a smaller size of housing while the amount of heat generated is approximately same, so that it will be more important technical task to deal with a heat-related problem. Accordingly, there has been provided a blower at a ventilation hole on a sidewall of the housing through which the heat internally generated is released out of the housing so as to prevent the electronic components from being thermally damaged.
A conventional blower of this type is hereinbelow described with reference to FIG.
3
.
Reference numeral
1
in
FIG. 3
denotes a casing approximately a cylindrical shape. A housing
2
is integrally formed at the center of the casing
1
and a cylindrical bearing support
3
is fitted and inserted in the center portion of the housing
2
.
The bearing support
3
supports outer races of two bearings
4
,
5
disposed at an interval while a shaft
6
is supported by inner races of the bearings
4
,
5
. A stop ring
7
is wore at a lower end of the shaft
6
which prevents the shaft
6
from being pulled out and positions the shaft
6
in the axial direction.
A reference numeral
8
denotes an impeller made of synthetic resin and consists of a cylindrical body
9
and blades
10
disposed on outer periphery of the cylindrical body
9
. The impeller
8
is mounted in such a manner that the body
9
is fitted and inserted into a cup-shaped motor yoke
11
.
The motor yoke
11
is connected to the top end of the shaft
6
through a zinc die-cast-made boss
12
. The shaft
6
has a knurling groove
13
thereon at its connecting portion with the boss
12
to improve a tight-fitting with the boss
12
. A ring-shaped permanent magnet
14
is fixed at an inner periphery of the motor yoke
11
.
A stator core
16
having a stator wire
15
wound around is fixed at an outside of the bearing support
3
. A circuit board mounting an electronic circuit, e.g. a PC board
17
, is mounted below the stator core
16
(at a static part) so as to supply a predetermined electric current to the stator wire
15
in order to activate a unit of the stator wire
15
on the stator core
16
, and a unit of the motor yoke
11
and the permanent magnet
14
to work respectively as stator and rotor for a brushless direct current motor.
The electronic circuit mounted on the PC board
17
controls an electric current supplying to the stator wire
15
in order to rotate the unit of the motor yoke
11
and the permanent magnet
14
relative to the unit of the stator wire
15
and the stator core
16
. The stator wire
15
is connected to the electronic circuit on the PC board
17
through a conductive wire, not shown. Moreover, a lead wire
18
is connected to the PC board
17
so that power is supplied to the PC board
17
therethrough.
The blower thus constructed is used by mounting at a ventilation hole of a housing (not shown) of an OA equipment. The blower is normally mounted at the ventilation hole in such a manner that the upper side in the drawing faces the exterior of the housing while directing the shaft
6
to be horizontal.
When a direct current of a predetermined voltage is supplied to the lead wire
18
, a current controlled by the electronic circuit on the PC board
17
flows to the stator wire
15
. Then a magnetic flux is generated from the stator core
16
, which rotates the motor yoke
11
and the impeller
8
at the center of the shaft
6
by mutually reacting with the magnetic flux generated from the permanent magnet
14
.
As a result, air within the housing at the lower side of the drawing is sucked and releases toward the upper direction of the drawing through a air cavity
19
, namely toward the outside of the housing. The interior of the housing is cooled by this ventilating performance.
As typically shown in
FIG. 3
, a conventional blower provides the PC board
17
disposed below the stator wire
15
and the stator core
16
without any consideration thereto such that the PC board
17
is nakedly exposed to the atmosphere. Thus, the PC board
17
is vulnerable to adverse effects of the stator wire
15
closely facing to the board and to the installation environment of the housing on which the blower is mounted.
Accordingly, over a long time use of the blower, the stator wire
15
may come into contact with the PC board
17
causing a short circuit, or a heat directly released from the stator wire
15
may deteriorate the characteristics of the electronic circuit (component
20
) or insulation properties of the PC board
17
.
If the blower is used in a dusty and/or a moisty environment, dust and moisture may directly settle onto the PC board
17
leading to the deterioration of the electronic circuit (components
20
) or short circuit. The electronic circuit (components
20
) on the PC board
17
is especially vulnerable to the dust and moisture causing an extensive reduction of insulation properties of the components. Any solution or improvement has been long waited in light of such drawback.
Furthermore, although cooling the interior of the housing, the blower itself generates heat. However, the conventional blower does not take into account the radiation effect of such self-generated heat, and therefore the heat gradually accumulates in the electronic circuit (components
20
) of the PC board, which deteriorates the function thereof.
SUMMARY OF THE INVENTION
The present invention has been made in light of such drawbacks described above, and an object thereof is to provide a blower being able to prevent deterioration of the electronic control circuit (components) due to a close disposition of a stator wire.
It is another object of the present invention to provide a blower in which the deterioration of the electronic control circuit, particularly a reduction of an insulation property, due to a close disposition to the stator wire or to an installation environment is properly prevented.
It is still another object of the present invention to provide a blower, in which an increase of temperature generated by the blower itself due to an accumulated heat are prevented as much as possible in order to maintain the electronic circuit function.
To achieve the above described objects, a blower according to a first aspect of the present invention comprises a bearing disposed at the center of an approximately cylindrical casing, a shaft supported by the bearing, a motor yoke mounted on the shaft while having an impeller on an outer periphery and a permanent magnet on an inner periphery thereof, a stator core having a stator wire wound around disposed at the inner side of the permanent magnet, and a circuit board mounting an electronic circuit for supplying a predetermined amount of electric current to the stator wire which closely disposed to the stator wire and the stator core, wherein a partition plate is interposed between the stator core having the stator wire and the circuit board.
A blower according to a second aspect of the present invention comprises a similar feature of the first aspect, wherein a case portion is formed close to the stator wire and the stator core, and a circuit board is stored within the case portion.
A blower according to a third aspect of the present invention, in the second aspect comprises a motor base integrally formed with the casing, a lid member integrally formed with a bearing support member connected to the motor base in such a manner as to cover the motor base, and at least the lid member being formed of excellent thermal conductive ma
Elkassabgi Heba
Le Dang
Minebea Co. Ltd.
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