Pumps – Motor driven – Electric or magnetic motor
Reexamination Certificate
2000-07-28
2002-05-28
Freay, Charles G. (Department: 3746)
Pumps
Motor driven
Electric or magnetic motor
C310S071000
Reexamination Certificate
active
06394767
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a blower and the manufacturing method of the same, which is used for a variety of office automation appliances (hereinafter referred to as “OA appliances”).
2. Conventional Art
Conventionally, in the most OA appliances, many electronic parts are accommodated in a casing, so, the electronic parts are threatened to be damaged due to a heat generated from the electronic parts and accumulated in the casing. And, in general, a ventilation hole is provided in a side wall of the casing and where a blower is installed to discharge the heat accumulated in the casing outside in order to avoid the above problems.
As an example of such blower, there is one such as shown in FIG.
4
.
In
FIG. 4
, a casing
1
forms a cylindrical venturi portion
2
(casing
1
). Inside the venturi portion
2
, there is an inclined surface at a small inclination angle to form an annular projection (throttle portion).
A motor base
3
is molded integrally at a central portion of one end side (lower in
FIG. 4
) of the venturi portion
2
(casing
1
).
The motor base
8
is formed in general from an annular base body
4
, a cylindrical bearing box portion
5
provided in hanging from a hole forming portion of the base body
4
and a base flange
6
formed in bending in the same direction with the bearing box portion
5
on a periphery edge portion of the base body
4
.
An annular floor
7
(hereinafter referred to as “central floor”) is formed inside the bearing box portion
5
and partitions the bearing box portion into two chambers (hereinafter referred to as “the first chamber at upper in FIG.
4
and the second chamber at lower in FIG.
4
”: signs are omitted).
Bearings (hereinafter referred to suitably as the first, the second bearings
10
,
11
) are coupled with the bearing box portion
5
in such a manner as they are disposed respectively in the first and second chambers, which support rotatably a shaft (rotor shaft)
12
inserted through a hole (sign is omitted) of the central floor
7
at two positions.
On one end (
FIG. 4
, lower) of the rotor shaft
12
a stopping ring
13
for preventing the shaft from being pulled out is installed. On the other end (
FIG. 4
, upper) of the rotor shaft
12
, knurling
14
are engraved. A cup-shaped yoke (motor yoke)
15
is held by insert-molding at the portion provided with knurling
14
. An impeller
16
is coupled with the motor yoke
15
. An impeller
16
is formed cylindrical and comprises an impeller body
17
to be coupled with the motor yoke
15
and a plurality of blades
18
held on the periphery of the impeller body
17
.
And, a ring-shaped magnet
19
is fixed on an inner circumferential side of the motor yoke
15
, with an adhesive. A stator assembly
20
is fixed outside of the bearing box portion
5
. The stator assembly
20
is in general formed of a stator core
21
, a coil
22
wound around the stator core
21
and an insulating body
28
interposed between the stator
21
and the coil
22
. A printed circuit board (hereinafter referred to as “PC board”)
24
is disposed at one end side (
FIG. 4
, lower) of the stator assembly
20
.
The PC board
24
comprises an electronic circuit (not shown) connected to the coil
22
through a terminal
25
provided on the coil
22
. This electronic circuit is adapted to control for rotation of the magnet
19
that is the impeller
16
for rotation by carrying out a current control to the coil
22
due to an electro-magnetic force between the coil
22
and the magnet
19
[that is, a rotor consisting of the magnet
19
, the motor yoke
15
and the stator assembly
20
(not shown) function as a brushless motor]. Further, the terminal
25
and the PC board
24
are connected by soldering.
In
FIG. 4
,
26
designates a lead to supply an electric power to the coil
22
through an electronic circuit.
The blower structure mentioned above is adapted to fix the PC board
24
to the stator assembly
20
by soldering the terminal
25
of the coil
22
consisting of the stator assembly
20
to the electronic circuit of PC board
24
.
And the substance
30
(for convenience' sake, called as a board fixing stator assembly) obtained by fixing PC board
24
to the stator assembly
20
is applied with a resin molding
31
by casting type and the obtained one (hereinafter for convenience' sake, referred to as a resin molded board fixed stator assembly)
32
is adapted to be adhered and fixed to the bearing box portion
5
.
In the blower structured above, a blow in an axial direction is generated by the rotation of the blades
18
of the impeller
16
in the venturi portion
2
, and the inside of the casing of the OA appliances is cooled by this blow and a damage of electronic parts installed in the OA appliances due to the heat generated is prevented.
Now, it has been desired to increase the productivity of a blower and to lower the manufacturing cost. However, in the above mentioned prior art, the board fixing stator assembly
80
is prepared by applying a resin molding with a casting type is applied, which includes many processes such as a resin casting process, a vacuum treatment process for evacuating air and a heat treatment process for accelerating hardening, and thereby, the productivity has been lowered and to that extent a higher manufacturing cost is invited.
For reference, it is considered to use an injection molding as a means enabling to reduce the number of process comparing with the casting type. However, when employing the injection molding in place of the casting type for the board fixing stator assembly
30
, a resin (resin molding
31
) thickness of the resin between the stator assembly
20
and the PC board
24
varies enormously, thereby, the PC board
24
is apt to be deformed, damaged and threatened to generate a wire cutting of the electronic circuit due to a sink of the resin (resin molding
31
). So that, even if the injection molding is employed, actually the above requirement (for productivity increasing and cost lowering) has not been appropriately responded.
The present invention has been made in the light of the above circumstance to provide a blower which enables to realize an increasing of productivity and lowering of the manufacturing cost without inviting a deformation and a damage, and a manufacturing method thereof.
According to a first aspect of the present invention, in a blower which comprisises a bearing box formed for housing a bearing in the center portion of a cylindrical casing, a rotor held on a shaft supported rotatably on the bearing, a stator consisting of a stator core and a coil and being held on the periphery of the bearing box, a ring-shaped magnet provided on the rotor spaced from the stator at a given gap and a PC board connected to an extracting terminal of the coil, and having an electronic circuit for carrying out a current controlling for the coil, the blower is characterized in that the. extracting terminal is projected out and connected electrically to the PC board to which the stator is injection-molded with a resin and the whole of the PC board is molded with a casting molding.
According to a second aspect of the present invention, in the constitution of the first aspect, the resin molding of the whole PC board is carried out by an injection molding.
According to a third aspect of the present invention, in the constitution of the second aspect, the whole of the PC board is coated or impregnated with a resin and the whole is injection-molded.
According to a fourth aspect of the present invention, in the constitution of the first aspect of the present invention, the molding of the whole of the PC board is carried out with the casting type molding.
According to a fifth aspect of the present invention, in a manufacturing method of a blower in which, a bearing box for housing a bearing in the center portion of a cylindrical casing is formed, a rotor is held on a shaft supported rotatably on the bearing, a stator consisting of a stator core and a coil is held on t
Freay Charles G.
Gray Michael K.
Minebea Co. Ltd.
Oliff & Berridg,e PLC
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