Information
-
Patent Grant
-
6559750
-
Patent Number
6,559,750
-
Date Filed
Wednesday, July 25, 200123 years ago
-
Date Issued
Tuesday, May 6, 200322 years ago
-
Inventors
-
Original Assignees
-
Examiners
Agents
-
CPC
-
US Classifications
Field of Search
US
- 336 83
- 336 200
- 336 223
- 336 232
-
International Classifications
-
Abstract
A transformer comprises first and second flat coils stacked with each other. Each of first and second flat coils comprises a conductive wire which is wound in a flat spiral shape having a through hole at a center thereof such that the conductive wire has an inner end and an outer end at an inner periphery and an outer periphery of the spiral shape, respectively. The inner end of the first flat coil passes through the through hole of the second flat coil, thus reducing the overall thickness of the transformer because both inner ends pass over only one flat coil.
Description
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to transformers and electrical devices using the same. In particular, the present invention relates to a transformer to be used for a switching power supply device and to an electrical device using the transformer.
2. Description of the Related Art
FIG. 10
is an exploded perspective view of a known thin transformer. In
FIG. 10
, a transformer
1
includes flat coils
2
,
3
, and
4
which are formed by winding wires in spirals and which coaxially overlap each other with doughnut-shaped insulative sheets
5
and
6
therebetween, and core members
7
and
8
sandwiching the flat coils
2
,
3
, and
4
and the insulative sheets
5
and
6
. The flat coils
2
,
3
, and
4
coaxially overlapping each other are individually provided with holes for passing a magnetic core-leg formed in central parts of the flat coils
2
,
3
, and
4
. The core members
7
and
8
are each provided with a magnetic core-leg.
FIG. 11A
is a plan view of the flat coil
3
of the transformer
1
.
FIG. 11B
is a sectional view along line A—A of the flat coil
3
shown in FIG.
11
A. In
FIG. 11A
, the flat coil
3
is formed with a wire
3
a
wound in a spiral. An inner end
3
b
of the wire
3
a
is drawn to the outside over the other part of the wire
3
a
. An outer end
3
c
of the wire
3
c
is drawn to the outside in the same winding direction.
The thickness of the overall flat coil
3
thus formed is substantially the same as the diameter of the wire
3
a
. However, the thickness of the flat coil
3
is at least twice the diameter of the wire
3
a
in a portion of the flat coil
3
over which the inner end
3
b
of the wire
3
a
is drawn to the outside. The flat coils
2
and
4
each have the same configuration as the flat coil
3
shown in
FIGS. 11A and 11B
.
The transformer I shown in
FIG. 10
includes the flat coils
2
,
3
, and
4
overlapping each other, each having the thickness twice the diameter of the wire
3
a
, whereby the thickness of the flat coils
2
,
3
, and
4
becomes six times the diameter of the wire
3
a
. Since the transformer
1
also includes the insulative sheets
5
and
6
each having a given thickness, there is a problem in that the thickness of the transformer
1
is increased.
SUMMARY OF THE INVENTION
Accordingly, it is an object of the present invention to provide a transformer which can be reduced in thickness and an electrical device using the transformer.
To the end, according to an aspect of the present invention, a transformer comprises a plurality of flat coils overlapping each other, each formed by winding a wire in a spiral. Respective inner ends of the wires forming at least two of the plurality of flat coils are drawn out through a hole for passing a magnetic core-leg and over one of the plurality of flat coils. The respective inner ends are disposed on the same surface of the one of the plurality of flat coils.
The inner ends of the other two of the plurality of flat coils may be connected to each other.
In the transformer according to the present invention, respective outer ends of the wires forming two of the plurality of flat coils may be connected to each other.
The wire forming at least one of the plurality of flat coils may be a three-layer insulated wire.
The wire may be a self-welding-type three-layer insulted wire.
An electrical device according to the present invention is provided which comprises the transformer described above.
The transformer according to the present invention can be reduced in thickness by arranging the same as described above.
The electrical device according to the present invention can be reduced in thickness and in size.
BRIEF DESCRIPTION OF THE DRAWING(S)
FIG. 1A
is an exploded perspective view of a transformer according to a first embodiment of the present invention;
FIG. 1B
is an exploded perspective view of a transformer according to a second embodiment of the present invention;
FIG. 2A
is a plan view of the transformer shown in
FIG. 1A
according to the first embodiment of the present invention;
FIG. 2B
is a sectional view along line B—B of the transformer shown in
FIG. 2A
according to the first embodiment of the present invention;
FIG. 3
is a sectional view of a transformer according to a third embodiment of the present invention;
FIG. 4
is an exploded perspective view of a transformer according to a fourth embodiment of the present invention;
FIG. 5
is an exploded perspective view of a transformer according to a fifth embodiment of the present invention;
FIG. 6
is an exploded perspective view of a transformer according to a sixth embodiment of the present invention;
FIG. 7
is an exploded perspective view of a transformer according to a seventh embodiment of the present invention;
FIG. 8
is an exploded perspective view of a transformer according to an eighth embodiment of the present invention;
FIG. 9
is a perspective view of an electrical apparatus according to a ninth embodiment of the present invention;
FIG. 10
is an exploded perspective view of a known transformer;
FIG. 11A
is a plan view of a flat coil used in the known transformer shown in
FIG. 10
; and
FIG. 11B
is a sectional view along line A—A of the flat coil shown in FIG.
11
A.
DETAILED DESCRIPTION OF EMBODIMENTS OF THE INVENTION
FIG. 1A
is an exploded perspective view of a transformer according to a first embodiment of the present invention.
FIG. 1B
is an exploded perspective view of a transformer according to a second embodiment of the present invention.
FIG. 2A
is a plan view of the transformer shown in
FIG. 1A
according to the first embodiment.
FIG. 2B
is a sectional view along line B—B of the transformer shown in
FIG. 2A
according to the first embodiment.
FIGS. 1A
,
1
B,
2
A, and
2
B show major portions of the transformer according to the present invention, in which core members corresponding to the core members
7
and
8
shown in
FIG. 10
are omitted so as to avoid complexity in the drawings, the core members being omitted from the drawings referred to in the following description.
In
FIGS. 1A
,
2
A, and
2
B, a transformer
10
a
includes flat coils
11
,
12
, and
13
coaxially stacked with each other, each formed with a wire wound in a spiral. Doughnut-shaped insulative sheets
14
and
15
are disposed between the flat coils
11
and
12
and between the flat coils
12
and
13
, respectively. In particular, the flat coils
11
,
12
, and
13
are formed with wires
11
a
,
12
a
, and
13
a
, respectively. Each of wires
11
a
,
12
a
, and
13
a
is wound in a spiral shape having a through hole at a center thereof such that the wire has an inner end and an outer end at the inner periphery and the outer periphery of the spiral shape, respectively. The flat coils
11
,
12
, and
13
overlapping each other with the doughnut-shaped insulative sheets
14
and
15
therebetween are provided with holes for passing a magnetic core-leg coaxially formed in a central part of each of the flat coils
11
,
12
, and
13
and the insulative sheets
14
and
15
. The inner end
11
b
of the wire
11
a
forming the flat coil
11
is drawn to the outside of the flat coil
11
, that is, the outside of the transformer
10
a
over a wound portion of the wire
11
a.
The inner end
12
b
of the wire
12
a
forming the flat coil
12
is drawn to the outside of the transformer
10
a
through the respective holes for passing a magnetic core-leg of the insulative sheet
14
and the flat coil
11
and over the wound portion of the wire
11
a
. An inner end
13
b
of the wire
13
a
forming the flat coil
13
is drawn to the outside of the transformer
10
a
through the respective holes for passing a magnetic core-leg of the insulative sheet
15
, the flat coil
12
, the insulative sheet
14
, and the flat coil
11
and over the wound portion of the wire
11
a
forming the flat coil
11
. That is, the inner ends
11
b
,
12
b
, and
13
b
of the flat coils
11
,
12
, and
13
, respectively, are disposed on the same surface of the flat coil
11
. Outer ends
11
c
,
12
c
, and
13
c
of the flat coils
11
,
12
,
13
, respectively, are drawn to the outside of the transformer
10
a
at the same levels as the flat coils
11
,
12
, and
13
, respectively.
In the thus formed transformer
10
a
, the inner ends
11
b
,
12
b
, and
13
b
are drawn to the outside of the transformer
10
a
over the wound portion of the wire
11
a
of the flat coil
11
and are disposed on the same surface of the flat coil
11
. Therefore, the thickness of the overall flat coils, which is the sum of the thickness of the three flat coils
11
,
12
, and
13
and the thickness of a portion of one of the flat coil
11
,
12
, and
13
, of which the inner ends
11
b
,
12
b
, and
13
b
, respectively, are drawn out, is substantially four times the diameter of the wire
11
a
. That is, the transformer
10
a
can be made thinner than the known transformer
1
shown in
FIG. 10
by a thickness corresponding to twice the diameter of a wire, whereby the overall transformer
10
a
can be reduced in thickness.
Although in the transformer
10
a
shown in
FIGS. 1A
,
2
A, and
2
B, the inner ends
11
b
,
12
b
, and
13
b
of the flat coils
11
,
12
, and
13
, respectively, are brought into contact with each other and into the flat coil
11
, it may be necessary to dispose the inner ends
11
b
,
12
b
, and
13
b
separated from each other and to provide an insulative film between the flat coil
11
and the inner ends
11
b
,
12
b
, and
13
b
according to the dielectric strength between the flat coils
11
,
12
, and
13
.
Although in the transformer
10
a
shown in
FIG. 1A
, the inner ends
11
b
,
12
b
, and
13
b
of the flat coils
11
,
12
, and
13
, respectively, are drawn out over the outer surface (upper side) of the outermost flat coil
11
, the inner ends
11
b
,
12
b
, and
13
b
may be drawn out over the outer surface (lower side) of the outermost flat coil
13
. The inner ends
11
b
,
12
b
, and
13
b
may be drawn out between the flat coils
11
and
12
or between the flat coils
12
and
13
. The inner ends
11
b
,
12
b
, and
13
b
may be drawn out in directions differing from each other, as in a transformer
10
b
according to a second embodiment shown in
FIG. 1B
, as long as the inner ends
11
b
,
12
b
, and
13
b
are each disposed on the same surface of one of the flat coils
11
,
12
, and
13
. When the inner ends
11
b
,
12
b
, and
13
b
are drawn out between two of the flat coils
11
,
12
, and
13
, an insulative film may be provided between the corresponding flat coil
11
,
12
, or
13
and the inner ends
11
b
,
12
b
, and
13
b
, as needed.
FIG. 3
is a sectional view of a transformer according to a third embodiment of the present invention. The transformer is shown in section along a line corresponding to the line B—B of the transformer
10
a
shown in FIG.
2
A. Components the same as or corresponding to those which are shown in
FIGS. 2A and 2
b
are referred to with the same reference numerals, for which description is omitted.
In a transformer
18
shown in
FIG. 3
, the inner end
13
b
of the wire
13
a
forming the flat coil
13
is drawn to the outside of the transformer
18
through the respective holes for passing a magnetic core-leg of the insulative sheet
15
, the flat coil
12
, the insulative sheet
14
, and the flat coil
11
and over the inner ends
11
b
and
12
b
of the flat coils
11
and
12
, respectively. That is, the inner ends
11
b
and
12
b
of the flat coils
11
and
12
, respectively, are disposed on the same surface of the flat coil
11
, and the inner end
13
b
of the flat coil
13
is disposed on the inner ends
11
b
and
12
b.
In the thus formed transformer
18
, the two inner ends
11
b
and
12
b
of the two flat coils
11
and
12
, respectively, are drawn to the outside of the transformer
18
over a wound portion of the wire
11
a
of the flat coil
11
on the same surface of the flat coil
11
. Therefore, the thickness of the overall flat coils
11
,
12
, and
13
, which is the sum of the thickness of the three flat coils
11
,
12
, and
13
, the thickness corresponding to the diameter of a portion of one of the wires
11
a
and
12
a
of which the inner ends
11
b
and
12
b
, respectively, are drawn out, and the thickness corresponding to the diameter of the inner end
13
b
of the wire
13
a
which is drawn out is substantially five times the diameter of a wire. Although the thickness of the overall flat coils of the transformer
18
is greater than that of the transformer
10
a
or
10
b
shown in
FIG. 1A
or
1
B, respectively, the transformer
18
can be made thinner than the known transformer
1
shown in
FIG. 10
by a thickness corresponding to the diameter of the wire
11
a
,
12
a
, or
13
a
, whereby the overall transformer
18
can be reduced in thickness.
The thickness of the transformer
18
can be reduced when the inner ends of at least two flat coils are each drawn out over a surface of one of the flat coils
11
,
12
, and
13
.
Although in the transformer
18
shown in
FIG. 3
, the inner ends
11
b
and
12
b
of the two flat coils
11
and
12
, respectively, are each drawn out over the outer side of the outermost flat coil
11
, the two inner ends
11
b
and
12
b
may be drawn out between two flat coils
11
and
12
or
12
and
13
, in the same way as in the transformer
10
a
or
10
b
shown in
FIG. 1A
or
1
B, respectively.
FIG. 4
is an exploded perspective view of a transformer according to a fourth embodiment of the present invention, in which components the same as or corresponding to those of the transformers
10
a
and
10
b
shown in
FIGS. 1A and 1B
, respectively, are referred to with the same reference numerals, for which description is omitted.
In a transformer
20
shown in
FIG. 4
, the inner ends
1
b and
13
b
of the wire
11
a
and
13
a
forming the flat coils
11
and
13
are drawn to the outside of the transformer
20
over a wound portion of the wire
11
a
forming the flat coil
11
, the inner end
13
b
being drawn through the respective holes for passing a magnetic core-leg of the insulative sheet
15
, the flat coil
12
, the insulative sheet
14
, and the flat coil
11
. That is, only the inner ends
11
b
and
13
b
of the flat coils
11
and
13
, respectively, are disposed on the same surface of the flat coil
11
. The inner end
12
b
of the wire
12
a
forming the flat coil
12
is drawn to the outside of the transformer
20
between the flat coils
11
and
12
, more particularly, between the insulative sheet
14
and the flat coil
12
over a wound portion of the wire
12
a.
In the thus formed transformer
20
, the two inner ends
11
b
and
13
b
of the two flat coils
11
and
13
, respectively, are drawn to the outside of the transformer
20
over the wound portion of the wire
11
a
of the flat coil
11
on the same surface of the flat coil
11
. Therefore, the thickness of the overall flat coils, which is the sum of the thickness of the three flat coils
11
,
12
, and
13
, the thickness corresponding to the diameter of one of the inner ends
11
b
and
12
b
of the wires
11
a
and
13
a
, respectively, which are drawn out, and the thickness corresponding to the diameter of the inner end
12
b
of the wire
12
a
which is drawn out is substantially five times the diameter of the wire
11
a
,
12
a
, or
13
a
. Although the thickness of the overall flat coils of the transformer
20
is greater than that of the transformer
10
a
or
10
b
shown in
FIG. 1A
or
1
B, respectively, the transformer
20
can be made thinner than the known transformer
1
shown in
FIG. 10
by a thickness corresponding to the diameter of the wire
11
a
,
12
a
, or
13
a
, whereby the thickness of the overall transformer
20
can be reduced.
The transformer
20
can be reduced in thickness when the inner ends of at least two flat coils are each drawn out over a surface of one of the flat coils
11
,
12
, and
13
.
Although in the transformer
20
shown in
FIG. 4
, the inner ends
11
b
and
13
b
of the two flat coils
11
and
13
, respectively, are each drawn out over the outer side of the outermost flat coil
11
, the two inner ends
11
b
and
13
b
may be drawn out between two flat coils
11
and
12
or
12
and
13
, in the same way as in the transformer
10
a
or
10
b
shown in
FIG. 1A
or
1
B, respectively.
FIG. 5
is an exploded perspective view of a transformer according to a fifth embodiment of the present invention, in which components the same as or corresponding to those of the transformers
10
a
and
10
b
shown in
FIGS. 1A and 1B
, respectively, are referred to with the same reference numerals, for which description is omitted.
A transformer
30
shown in
FIG. 5
is provided with a flat coil
31
in addition to the transformer
10
a
or
10
b
shown in
FIG. 1A
or
1
B, respectively, the flat coil
31
being disposed on the outer side of the flat coil
13
with a doughnut-shaped insulative sheet
32
between the flat coils
13
and
31
. The flat coil
31
is formed by winding a wire in a spiral. An end
31
b
of a wire
31
a
forming the flat coil
31
is drawn to the outside of the transformer
30
through the holes for passing a magnetic core-leg of the insulative sheet
32
, the flat coil
13
, the insulative sheet
15
, the flat coil
12
, the insulative sheet
14
, and the flat coil
11
and over a wound portion of the wire
11
a
of the flat coil
11
. That is, the inner ends
11
b
and
31
b
of the flat coils
11
and
31
, respectively, are each disposed on the same surface of the flat coil
11
. The inner end
12
b
of the wire
12
a
forming the flat coil
12
and the inner end
13
b
of the wire
13
a
forming the flat coil
13
are connected to each other in the holes for passing a magnetic core-leg of the flat coils
12
and
13
and the insulative sheet
15
. The outer ends
11
c
,
12
c
,
13
c
and
31
c
of the four flat coils
11
,
12
,
13
, and
31
, respectively, are drawn to the outside of the transformer
30
at respective levels of the flat coils
11
,
12
,
13
, and
31
.
The thus formed transformer
30
can be reduced in thickness by drawing the inner ends
11
b
and
31
b
of the two flat coils
11
and
31
, respectively, to the outside of the transformer
30
, each inner end
11
b
or
31
b
being disposed on the same surface of the flat coil
11
. The inner ends
12
b
and
13
b
of the two flat coils
12
and
13
, respectively, are connected to each other, whereby the inner ends
12
b
and
13
b
are not necessarily drawn to the outside of the transformer
30
, thereby omitting a process of preparing lead wires, simplifying winding structures, and reducing manufacturing costs of windings.
FIG. 6
is an exploded perspective view of a transformer according to a sixth embodiment of the present invention, in which components the same as or corresponding to the transformer
10
a
or
10
b
shown. in
FIG. 1A
or
1
B, respectively, are referred to with the same reference numerals, for which description is omitted.
In a transformer
40
shown in
FIG. 6
, the outer end
11
c
of the flat coil
11
and the outer end
13
c
of the flat coil
13
are connected to each other.
In the thus formed transformer
40
, the flat coils
11
and
13
can be continuously wound by connecting the outer ends
11
c
and
13
c
of the flat coils
11
and
13
, respectively, to each other, thereby omitting a process of preparing lead wires, simplifying winding structures, and reducing manufacturing costs of windings.
FIG. 7
is an exploded perspective view of a transformer according to a seventh embodiment of the present invention. A transformer
50
shown in
FIG. 7
includes flat coils
51
,
52
, and
53
coaxially overlapping each other, each formed by winding a three-layer insulated wires in a spiral. The flat coils
51
,
52
, and
53
are formed by winding wires
51
a
,
52
a
, and
53
a
, respectively. An inner end
51
b
of the wire
51
a
forming the flat coil
51
is drawn to the outside of the transformer
50
over a wound. portion of the wire
51
a
. An inner end
52
b
of the wire
52
a
forming the flat coil
52
is drawn to the outside of the transformer
50
through a hole for passing a magnetic core-leg of the flat coil
51
and over the wound portion of the wire
51
a
of the flat coil
51
. An end
53
b
of the wire
53
a
forming the flat coil
53
is drawn to the outside of the transformer
50
through the respective holes for passing a magnetic core-leg of the flat coils
52
and
51
and over the wound portion of the wire
51
a
of the flat coil
51
. The inner ends
51
b
,
52
b
, and
53
b
of the flat coils
51
,
52
, and
53
, respectively, are each disposed on the same surface of the flat coil
51
. Outer ends
51
c
,
52
c
, and
53
c
of the three flat coils
51
,
52
, and
53
are drawn to the outside of the transformer
50
at respective levels of the flat coils
51
,
52
, and
53
. The three-layer insulated wire is a conducting wire coated with three layers of insulating materials differing from each other about the conducting wire, thereby providing a high dielectric strength.
The thus formed transformer
50
differs from the transformers
10
a
and
10
b
shown in
FIGS. 1A and 1B
, respectively, in that the transformer
50
is not provided with insulative sheets between the flat coils
51
and
52
and between the flat coils
52
and
53
. This is because the dielectric strength between the flat coils
51
,
52
, and
53
becomes large by virtue of the three-layer insulated wires
51
a
,
52
a
, and
53
a
, whereby the insulative sheets
14
and
15
can be eliminated.
Since the insulative sheets
14
and
15
can be eliminated by using the three-layer insulated wires
51
a
,
52
a
, and
53
a
, the thickness of the transformer
50
can be reduced further.
FIG. 8
is an exploded perspective view of a transformer according to an eighth embodiment of the present invention, in which components the same as or corresponding to those of the transformer
50
shown in
FIG. 7
are referred to with the same reference numerals, for which description is omitted.
In a transformer
60
shown in
FIG. 8
, the inner end
51
b
of the wire
51
a
forming the flat coil
51
is drawn to the outside of the transformer
60
between the flat coils
51
and
52
and over a wound portion of the wire
52
a
of the flat coil
52
. The inner end of the wire
52
a
forming the flat coil
52
is drawn to the outside of the transformer
60
over the wound portion of the wire
52
a
. The inner end
53
b
of the wire
53
a
forming the flat coil
53
is drawn to the outside of the transformer
60
through the hole for passing a magnetic core-leg of the flat coil
52
and over the wound portion of the wire
52
a
of the flat coil
52
. That is, the inner ends
51
b
,
52
b
, and
53
b
of the flat coils
51
,
52
, and
53
, respectively, are disposed between the flat coils
51
and
52
and on the same surface of the flat coil
52
.
In the thus formed transformer
60
in which the inner ends
51
b
,
52
b
, and
53
b
of the three flat coils
51
,
52
, and
53
, respectively, are drawn out between the flat coils
51
and
52
, insulative sheets, for ensuring the dielectric strength between the flat coil
51
and the inner ends
51
b
,
52
b
, and
53
b
and between the inner ends
51
b
,
52
b
, and
53
b
and the flat coil
52
, are not provided because a sufficient dielectric strength is maintained by using the three-layer insulated wires
51
a
,
52
a
, and
53
a
. Therefore, the thickness of the transformer
60
can be reduced further.
FIG. 9
is a perspective view of an electrical apparatus according to a ninth embodiment of the present invention, in which an electrical device
70
is a switching power supply device which uses the transformer
10
a
according to the present invention. The electrical device
70
includes a substrate
71
mounted with the transformer
10
a
according to the present invention, resistors, capacitors, choke coils, etc., and semiconductors such as transistors, diodes, and integrated circuits, these components being connected to each other via wires formed on the substrate
71
.
The thus formed electrical device
70
can be reduced in thickness and in size by reducing the thickness of the transformer
10
a.
Although the switching power supply device is shown in
FIG. 9
as an electrical device, the present invention may be applied to other electrical devices, such as analogue circuits and speaker devices, which use transformers according to the present invention.
Claims
- 1. A transformer comprising:first and second flat coils being stacked with each other, each of the first and second flat coils comprising a conductive wire which is wound in a flat spiral shape having a through hole at a center thereof such that the conductive wire has an inner end and an outer end at an inner periphery and an outer periphery of the spiral shape, respectively, wherein the inner end of the first flat coil passes through the through hole of the second flat coil.
- 2. The transformer of claim 1, further comprising third and fourth flat coils each comprising a conductive wire which is wound in a flat spiral shape having a through hole at a center thereof such that the conductive wire has an inner end and an outer end at an inner periphery and an outer periphery of the spiral shape, respectively,wherein the inner end of the third and fourth flat coils are connected with each other.
- 3. The transformer of claim 1, further comprising third and fourth flat coils each comprising a conductive wire which is wound in a flat spiral shape having a through hole at a center thereof such that the conductive wire has an inner end and an outer end at an inner periphery and an outer periphery of the spiral shape, respectively, wherein the outer end of the third and fourth flat coils are connected with each other.
- 4. The transformer of claim 1, wherein the wire forming at least one of the first and second flat coils is an insulated wire.
- 5. The transformer of claim 4, wherein the wire forming at least one of the first and second flat coils is a three layer insulated wire.
- 6. The transformer of claim 5, wherein said wire is a self-welding-type three-layer insulated wire.
- 7. The transformer of claim 1, further comprising an insulating sheet having a through hole and being provided between the first and second flat coils, the inner end of the first flat coil passing through the through hole of the insulating layer.
- 8. The transformer of claim 1, further comprising a core, at least a portion of the core passing through the through holes of the first and second flat coils.
- 9. The transformer of claim 1, further comprising a third flat coil stacked with the first and second flat coils and comprising a conductive wire wound in a flat spiral shape and having a through hole at a center thereof such that the conductive wire has a an inner and an outer end at an inner periphery and an outer periphery of the spiral shape, respectively, wherein the inner end of the third coil passes through the through hole of at least one of the first and second flat coils.
- 10. The transformer of claim 9, wherein the inner end of the third coil passes through the through hole of both the first and second flat coils.
- 11. An electrical device comprising a transformer and a circuit coupled to the transformer, the transformer comprising:first and second flat coils being stacked with each other, each of the first and second flat coils comprising a conductive wire which is wound in a flat spiral shape having a through hole at a center thereof such that the conductive wire has an inner end and an outer end at an inner periphery and an outer periphery of the spiral shape, respectively, wherein the inner end of the first flat coil passes through the through hole of the second flat coil.
- 12. The electrical device of claim 11, further comprising third and fourth flat coils each comprising a conductive wire which is wound in a flat spiral shape having a through hole at a center thereof such that the conductive wire has an inner end and an outer end at an inner periphery and an outer periphery of the spiral shape, respectively,wherein the inner end of the third and fourth flat coils are connected with each other.
- 13. The electrical device of claim 11, further comprising third and fourth flat coils each comprising a conductive wire which is wound in a flat spiral shape having a through hole at a center thereof such that the conductive wire has an inner end and an outer end at an inner periphery and an outer periphery of the spiral shape, respectively, wherein the outer end of the third and fourth flat coils are connected with each other.
- 14. The electrical device of claim 11, further wherein the wire forming at least one of the first and second flat coils is an insulated wire.
- 15. The electrical device of claim 14, further wherein the wire forming at least one of the first and second flat coils is a three layer insulated wire.
- 16. The electrical device of claim 15, further wherein said wire is a self-welding-type three-layer insulated wire.
- 17. The electrical device of claim 11, further comprising an insulating sheet having a through hole and being provided between the first and second flat coils, the inner end of the first flat coil passing through the through hole of the insulating layer.
- 18. The electrical device of claim 11, further comprising a core, at least a portion of the core passing through the through holes of the first and second flat coils.
- 19. The electrical device of claim 11, further comprising a third flat coil stacked with the first and second flat coils and comprising a conductive wire wound in a flat spiral shape and having a through hole at a center thereof such that the conductive wire has an inner end and an outer end at an inner periphery and an outer periphery of the spiral shape, respectively, wherein the inner end of the third coil passes through the through hole of at least one of the first and second flat coils.
- 20. The electrical device of claim 11, further wherein the inner end of the third coil passes through the through hole of both the first and second flat coils.
Priority Claims (1)
Number |
Date |
Country |
Kind |
2000-229752 |
Jul 2000 |
JP |
|
US Referenced Citations (2)
Number |
Name |
Date |
Kind |
5631822 |
Silberkleit et al. |
May 1997 |
A |
6211767 |
Jitaru |
Apr 2001 |
B1 |
Foreign Referenced Citations (1)
Number |
Date |
Country |
05006829 |
Jan 1993 |
JP |