Electrical generator or motor structure – Dynamoelectric – Rotary
Reexamination Certificate
2000-05-02
2001-08-21
Ramirez, Nestor (Department: 2834)
Electrical generator or motor structure
Dynamoelectric
Rotary
C310S06800R
Reexamination Certificate
active
06278207
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a improved blower for use in a variety of OA (office automation) equipment.
2. Description of the Related Art
Each OA equipment houses many electronic circuits within its casing, so that the heat generated by electronic parts constituting those electronic circuits are hard to be discharged. Because of this, there is a fear that some of the electronic parts are broken or deteriorated. Particularly in view of the recent trend towards downsizing of the OA equipment, in which the equipment is simply reduced in size despite the absence of significant reduction in quality of the generated heat, countermeasures against the heat has come to an important technical object. Then troubles that would be caused by heat generated inside is prevented by forming a ventilation hole on a side wall of the equipment and mounting a blower around the hole to discharge the internal heat to the outside of the equipment.
An example of a blower that has been frequently used will now be described with reference to FIG.
3
. Reference symbol
1
denotes a tubular casing the inside of which is sloped to form a venturi portion
2
. A housing
3
is formed integrally with this casing
1
at the center. A bearing housing
4
is formed on the central portion of the housing. Outer races of bearings
5
and
6
are supported inside the bearing housing
4
and a shaft
7
is fitted and inserted to inner races of the bearings
5
and
6
. A ring
8
is mounted at the lower end of the shaft
7
to prevent thereby the shaft
7
from being pulled out and position the shaft
7
in the axial direction.
Reference symbol
9
denotes an impeller made of synthetic resins. This impeller
9
comprises a body
10
having in section a shape of letter C and blades
11
formed around the periphery of the body
10
, which are integrally formed. In forming the impeller
9
, a ring-shaped motor yoke
12
is insert-molded at the inner circumferential portion of the body
10
and the shaft
7
is insert-molded at the central portion of the body
10
. A knurling groove
13
is formed near the top end of the shaft
7
so that the shaft
7
is tightly joined to the body
10
at the time of the insert molding, preventing separation from the body
10
during rotation. A ring-shaped magnet
14
is fixed by adhesives to the inner circumference of the motor yoke
12
. These parts together form a rotary part. A ring-shaped spring
15
is interposed between a portion of the body
10
near the shaft
7
and the inner race of the bearing
5
, which gives the impeller
9
an upward pressurization in the drawing.
A stator core
17
around which a stator coil
16
is coiled is arranged on the outside of the bearing housing
4
and fixed to the bearing housing
4
to form a stationary part. A PC (printed circuit) board
18
on which electronic circuits as a brushless motor are formed from electronic parts is mounted on a lower portion of the stator core
17
. The electronic circuits incorporated into this PC board
18
control current for rotating the rotary part relative to the stationary part. A pin-like connecting terminal
19
is projected downward from the stator core
17
to pierce through a part of the PC board
18
, thereby electrically connecting the stator coil
16
to the circuits on the PC board
18
. A lead
20
is connected to the PC board
18
for feeding electric power to the PC board
18
.
The thus constructed blower is used when mounted around the ventilation hole of the casing of the OA equipment. In the mounting work, the upper side of the blower in the drawing is directed to the outside of the box of the OA equipment with the shaft
7
being directed in the horizontal direction. When a predetermined voltage is fed from a power source to the lead
20
under this condition, the current controlled by a control circuit on the PC board
18
is caused to flow through the stator coil
16
so that the rotary part is rotated by a magnetic interference action between the magnetic flux generated in the stator core
17
and the magnetic flux generated by the magnet
14
. The impeller
9
is rotated so that the air in the lower part of the box in the drawing is sucked and is discharged from the venturi portion
2
toward the outside in the upper part in the drawing. With this air flow operation, the interior of the casing is cooled.
The blower with the above structure has no problem when adopted by equipment used in a usual office. However, the PC board in the blower is not completely covered, which makes the blower unsuitable for use under severe circumstances such as construction sites especially in terms of dust-proof and drip/water-proof characteristics.
SUMMARY OF THE INVENTION
The present invention has been made in view of the above, and an object of the present invention is therefore to provide a blower that is suitable for use in severe circumstances.
In order to attain the above object, according to a first aspect of the present invention, there is provided a blower constructed by forming a bearing housing at the center of a tubular casing, supporting a shaft with bearings that are supported by the bearing housing, attaching a impeller, a motor yoke, etc., to the shaft, and arranging a stator core with a stator coil wound thereabout inside the motor yoke, the blower characterized in that one end of the bearing housing is elongated and expanded to form a shape of letter C, a chamber formed within the C-shaped portion houses a PC board with a control circuit mounted thereon, a connection terminal projected from the stator coil is connected to electronic circuits mounted on the PC board, and a opening of the chamber is covered with a lid plate. Incidentally, the “blower” referred to herein means an axial flow fan motor and a centrifugal fan motor, and the centrifugal fan motor further includes a blower, a cross-flow type and motor impellized type.
Also, according to a second aspect of the present invention, the blower in the first aspect of the invention is characterized in that the entire outer peripheral portion of the stator coil and the stator core is coated with synthetic resins, and the coating is partially removed to expose solely the connection terminal connected to the electronic circuits on the PC board and to fit and fix the connection terminal to the PC board.
Furthermore, according to a third aspect of the present invention, the blower in the first aspect of the invention is characterized in that the entire peripheral portion of the stator coil and the stator core is coated with synthetic resins, the coating is partially removed to expose solely the connection terminal connected to the electronic circuits on the PC board and to fit and fix the connection terminal to the PC board, and a filler is injected in the interior of a chamber that houses the PC board.
With the structure according to each aspect of the present invention, the PC board is housed within the chamber and is covered by the lid plate and, furthermore, the filler tightly seals the chamber. The PC board is thus protected from dust, moisture, oil, etc.
REFERENCES:
patent: 5786648 (1998-07-01), Iwanami
Jones Judson H.
Minebea Co. Ltd.
Oliff & Berridg,e PLC
Ramirez Nestor
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