Inductor devices – Coil or coil turn supports or spacers – Printed circuit-type coil
Reexamination Certificate
2001-06-20
2003-10-14
Enad, Elvin (Department: 2832)
Inductor devices
Coil or coil turn supports or spacers
Printed circuit-type coil
C336S083000, C336S183000, C336S192000, C336S200000, C336S223000, C336S232000
Reexamination Certificate
active
06633220
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a coil apparatus for use as a transformer or a choke coil, for example, and to a method for manufacturing the coil apparatus.
2. Description of the Related Art
FIG. 5A
is an exploded view of a conventional of a coil apparatus;
FIG. 5B
is a sectional view of the coil apparatus shown in
FIG. 5A
at the line A—A. A coil apparatus
1
shown in
FIGS. 5A and 5B
comprises a substrate
2
for mounting electronic components thereon, a coil pattern
3
formed on the substrate
2
, a core
4
comprised of a pair of core members
4
a
and
4
b,
and a core-combining member
5
.
The substrate
2
having electronic components and a circuit pattern mounted thereon, which form a circuit, is preferably a multilayer substrate formed by joining plural substrates together. For example, the plural substrates which form the substrate
2
may respectively have coil patterns
7
coaxially formed about an axis defined on the substrate
2
. The coil pattern
3
is formed by connecting a plurality of the coil patterns
7
. In addition, when the coil apparatus
1
is to be a transformer apparatus, at least one of the plural coil patterns
7
forms a primary coil and the remaining coil patterns
7
form one or more secondary coils.
In the example shown in
FIGS. 5A and 5B
, the core members
4
a
and
4
b
are molded by pressing and sintering magnetic powder such as ferrite, and are E-shaped in cross-section, each having a planar bar portion
8
and core legs
9
a,
9
b,
and
9
c
arranged to respectively extend from one end, the center, and the other end of the bar portion
8
.
The substrate
2
is provided with through-holes
10
a,
10
b,
and
10
c
for receiving the core legs
9
a,
9
b,
and
9
c,
respectively. The through-hole
10
b
is formed within the coil pattern
3
. Into these through-holes
10
a,
10
b,
and
10
c,
as shown in
FIG. 5B
, the core legs
9
a,
9
b,
and
9
c
of the core members
4
a
and
4
b
are respectively inserted from top and bottom surfaces of the substrate
2
, so that the core legs
9
a,
9
b,
and
9
c
of the core member
4
a
on the top side respectively abut the core legs
9
a,
9
b,
and
9
c
of the core member
4
b
on the bottom side.
The core-combining member
5
, as is shown in
FIG. 5B
, is disposed surrounding the pair of core members
4
a
and
4
b
and elastically holds them together. The core-combining member
5
is made by bending a metallic plate so as to form a web
12
, leg portions
13
a
and
13
b,
and claw portions
14
a
and
14
b.
That is, the two sides of the web
12
covering the bar portion
8
of the core member
4
a
are respectively bent in the direction along the core legs
9
a
and
9
c
of the core members
4
a
and
4
b
so as to form the leg portions
13
a
and
13
b;
and the ends of the leg portions
13
a
and
13
b
are further bent inwardly so as to form the claw portions
14
a
and
14
b.
The space between the web
12
and the claw portions
14
a
and
14
b,
as is shown in
FIG. 5B
, is approximately the same as the distance h from the top surface
8
a
of the bar portion
8
of the core member
4
a
to the top surface
8
a
of the bar portion
8
of the core member
4
b
when the core legs
9
of the core member
4
a
on the top side are abutted with the core legs
9
of the core member
4
b
on the bottom side. As is shown in
FIG. 5B
, the web
12
and the claw portions
14
a
and
14
b
clamp the bilateral sides of the core members
4
a
and
4
b
in the abutment state from both sides and from the top and bottom sides. Thereby, the core members
4
a
and
4
b
are combined together so as to be relatively movable in the direction &agr; (front-and-rear) indicated in FIG.
5
A. The through-holes
10
a,
10
b,
and
10
c
have the length W in the front-to-rear direction, along which the core members
4
a
and
4
b
can move in the front-to-rear direction as mentioned above.
The coil apparatus
1
shown in
FIGS. 5A and 5B
is assembled as follows: First, the core member
4
a
is arranged above the substrate
2
on which the coil pattern section
3
and the through-holes
10
a,
10
b,
and
10
c
are formed while the core member
4
b
is arranged below the substrate
2
. The core legs
9
a,
9
b,
and
9
c
of the top core member
4
a
are inserted into corresponding through-holes
10
a,
10
b,
and
10
c
from the top of the substrate
2
while similarly, the core legs
9
a,
9
b,
and
9
c
of the bottom core member
4
b
are inserted into the corresponding through-holes
10
a,
10
b,
and
10
c
from the bottom of the substrate
2
. Thus, the core legs
9
a,
9
b,
and
9
c
of the top core member
4
a
are abutted against the core legs
9
a,
9
b,
and
9
c
of the bottom core member
4
b,
respectively.
From the upper side of the core members
4
a
and
4
b
in the abutment state, the left leg portion
13
a
of the core-combining member
5
is inserted into the left through-hole
10
a
while the right leg portion
13
b
of the core-combining member
5
is inserted into the right through-hole
10
c,
the through-holes
10
a
and
10
c
respectively corresponding to the outward core legs
9
a
and
9
c
of the core members
4
a
and
4
b.
Thereby, the core members
4
a
and
4
b
in the abutment state and the core-combining member
5
are fitted with each other so that the core members
4
a
and
4
b
are assembled to the substrate
2
by being combined with the core-combining member
5
. In such a manner, by being assembled to the substrate
2
, the core members
4
a
and
4
b
sandwich a part of the coil pattern section
3
therebetween from the top and bottom sides of the substrate
2
.
Then, the combined core members
4
a
and
4
b
are relatively slid in the front-to-rear direction, so that the abutment portions between the core members
4
a
and
4
b,
namely the ends of the core legs
9
a,
9
b,
and
9
c
which are abutted with each other, are rubbed together. By rubbing the ends of the core legs
9
a,
9
b,
and
9
c
together, the following advantages can be obtained.
Since as described above the core members
4
a
and
4
b
are molded by sintering magnetic powder, the end faces of the core legs
9
a,
9
b,
and
9
c
of the core members
4
a
and
4
b
are rough, and also dust may get in between the end faces of the core legs
9
a,
9
b,
and
9
c
which are abutted to each other when combining the core members
4
a
and
4
b
together. Thus, adhesion between the end faces of the core legs
9
a,
9
b,
and
9
c
which are abutted to each other may be low. But by rubbing the end faces of the core legs
9
a,
9
b,
and
9
c
against each other by rubbing the cores together as mentioned above, the end faces of the core legs
9
a,
9
b,
and
9
c
are polished to have substantially a mirror finish, while dust which has gotten in between the end faces of the core legs
9
a,
9
b,
and
9
c
is crushed and removed, thereby improving the contact between the end faces of the core legs
9
a,
9
b,
and
9
c
of the top core member
4
a
and the end faces of the core legs
9
a,
9
b,
and
9
c
of the bottom core member
4
b.
By contacting the core members
4
a
and
4
b
together in such a manner, inductance can be improved, thereby improving the performance of the coil apparatus.
However, in the conventional structure, as is shown in
FIG. 5B
, internal faces
8
b
of the bar portion
8
of the core member
4
a
are necessarily brought into contact with a surface of the substrate
2
. Therefore, the surface of the substrate
2
is rubbed by the internal faces
8
b
of the bar portion
8
when rubbing the cores together, which may cause a protecting member such as a resist formed on the surface of the substrate
2
to be damaged or to be peeled off. Such damage to the protecting member may cause a problem, in that a circuit pattern such as copper formed on the substrate
2
may corrode or its withstand-voltage performance may be reduced when the coil apparatus is placed under high-humidity circumstances for a long time.
SUM
Inoue Keiji
Ishige Tsutomu
Enad Elvin
Keating & Bennett LLP
Murata Manufacturing Co. Ltd.
Poker Jennifer A.
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