JP2002237419A - Planar transformer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make the size and thickness of a planar transformer reducible by enlarging the occupied area of a conductive disc coil by making the insulation distances between the conductive disc coil and a core and between the disc coil and its adjacent coil easily securable. SOLUTION: The conductive disc coil 9 has recessed sections 13 at the corner sections of the marginal section of its core inserting hole 10, projecting sections 14 at central parts of the sides of the marginal section, and notched sections 15 at corner sections of its outer peripheral section. The coil 9 is housed in a square flat ring-like bag 29 having a square core inserting hole 20 (22) at the center of one insulating film carrying an adhesive on one surface, and the insulating films are stuck to both surfaces of the coil 9.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a planar transformer used for a power supply device of an electronic apparatus.

[0002]

2. Description of the Related Art In general, a large-capacity transformer used in a power supply device of an electronic device or the like flows a large current. Then, the coil occupancy of the transformer increases, and the shape of the transformer tends to increase. However, since the power supply device and the like are required to be small and thin, the transformer used therein must also be small and thin. Therefore, in order to reduce the size and thickness of the transformer, it is necessary to reduce the coil occupancy of the transformer.A single-layer or multiple-layer printed coil in which copper foil is arranged in a flat spiral shape on a substrate, etc. A planar transformer using a plurality of stacked copper plate coils is proposed.

In this planar transformer, for example, a plurality of printed coils are connected and used on the primary side, and a plurality of flat plate-shaped copper plate coils are connected and used on the secondary side. Then, as shown in FIG. 6, the upper and lower E-shaped cores 1 (1
a, 1b), the print coil 2 (2
a, 2b) and the copper plate coils 3 (3a, 3b) are alternately arranged, and a flat ring-shaped insulator 4 (4a,... 4d) is interposed between the coils 2 and 3 above and below. Are sandwiched between the upper and lower cores 1. Then, flat bodies such as the print coil 2, the copper plate coil 3, and the insulating plate 4 can be laminated and provided. Note that four terminal rods 5 (5a,... 5d) are used as external terminals of the primary and secondary coils.

[0004]

However, such a planar transformer has a smaller insulation distance between the copper plate coil 3 and the core 1 and between the copper plate coil 3 and the adjacent print coil 2 as compared with a conventional winding type transformer. It is not easy to secure each one. Therefore, there is a problem that the area occupied by the copper plate coil or the like cannot be increased. When the copper plate coil 3 is formed in a symmetrical shape, the copper plate is formed into a square flat plate ring shape as shown in FIG. 7, and the inside of the ring is formed into a square core insertion hole 6, and the center of one side of the ring is formed. A slit 7 for cutting the ring is provided. Then, the flat plates 8 (8a, 8b) are drawn out from both sides of the slit 7 of the copper plate coil 3, respectively.

The present invention has been made in view of such a conventional problem, and it has been made easy to secure an insulation distance between a conductive plate coil and a core and between a conductive plate coil and an adjacent coil. It is an object of the present invention to provide a planar transformer that can be reduced in size and thickness by increasing the area occupied by the coil.

[0006]

In order to achieve the above object, in a planar transformer according to the present invention, a conductive plate is formed in at least a part of a coil in a flat plate ring shape, and a square core is formed in the ring. A conductive plate coil having an insertion hole and a slit for cutting a part of the ring is used. And, at the edge of the core insertion hole of the conductive plate coil,
Each corner of the edge is provided with a concave portion which recedes outward, and the center of each side of the edge is a projection which projects inward. Further, the conductive plate coil is housed in a flat ring-shaped bag made of one insulating film coated with an adhesive on one side and having a square core insertion hole in the center, and the insulating film is formed on both sides of the conductive plate coil. Attach.

Further, in the planar transformer according to the present invention, a conductive plate is formed in at least a part of a coil thereof in the shape of a square flat plate ring, and the inside of the ring is formed as a square core insertion hole, and a part of the ring is formed. A conductive plate coil provided with a slit for cutting is used. The conductive plate coil is provided with a concave portion that retreats outward at each corner of the core insertion hole and at each corner of the edge, and the center of each side of the edge is inward. A notch is provided at each corner of the outer edge of the conductive plate coil. Also, the conductive plate coil is coated with an adhesive on one side.
It is housed in a square flat ring-shaped bag made of a piece of insulating film and provided with a square core insertion hole in the center, and the insulating film is attached to both sides of the conductive plate coil

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. FIG. 1 is a plan view of a copper plate coil housed in an insulating film bag used for a planar transformer to which the present invention is applied and terminals drawn from the copper plate coil. As shown in FIG. 2, the copper plate coil 9 is also formed by forming a copper plate into a square plate ring shape, forming a square core insertion hole 10 in the ring, and slitting the ring at the center of one side of the ring. Is provided.
Then, two rectangular flat plates are pulled out from both sides of the slit 11 of the copper plate coil 9, and each of them is connected to a terminal 12 (12).
a, 12b).

At the edge of the core insertion hole 10 of the copper plate coil 9, for example, an L-shaped recess 13 (13a,..., 13d) is provided at each corner of the edge. Then, the center of each side of the edge becomes a rectangular protrusion 14 (14a,... 14d) protruding inward.
Moreover, the projection 14 c is divided into two by the slit 11. Further, each of the corners of the outer edge of the copper plate coil 9 is cut out in a notch 15 (1
5a,... 15d).

[0010] Such a copper plate coil 9 together with its terminals 12 is formed by punching a large number of plates at once from a large flat copper plate by pressing. Then, the copper plate coil 9
3 is accommodated in a bag and is insulated and covered with an insulating film 16 corresponding to the unfolded shape of the bag shown in FIG.
Is used. This insulating film 16 is the film body 1
7 is made rectangular, and its outer dimensions are slightly longer both vertically and horizontally than the outer diameter dimension connecting both sides of the copper plate coil 9. The film body 17 is bent at a solid line position 18 that divides the longitudinal direction into two equal parts, and a square core insertion hole 2 is formed at the center of one of the substantially square surface covering film portions 19.
0, and a square core insertion hole 22 is also provided at the center of the other approximately square surface coating film portion 21.

In addition, the surface covering film portion 21 has a trapezoidal bent piece 23 (23a, 23a) which is longer and narrower than two opposite sides corresponding to the long side of the film body 17.
b) is respectively provided. The trapezoidal bent piece 24 (2), which is also elongated from the four sides of the inner edge forming the core insertion hole 22.
4a,... 24d) are respectively protruded. At this time, the width of the bent piece 24 is made equal to the depth of the L-shaped concave portion 13 provided at the edge of the core insertion hole 10 of the copper plate coil 9, and the width of the bent piece 23 is about twice as large. In addition, solid line positions 25 and 26 corresponding to the roots of the bent pieces 23 and 24 are set as bent portions, respectively.

[0012] Such an insulating film 16 is also usually formed by punching a large number of single-layer or multi-layer insulating films having an adhesive applied to one surface by pressing. When the copper plate coil 9 is to be insulated, the copper plate coil 9 is first moved in the direction of the arrow to be superimposed on the surface covering film portion 21 constituting the film body 17 of the insulating film 16. At this time, the core insertion hole 22 of the surface covering film portion 21 and the core insertion hole 10 provided in the copper plate coil 9 are formed.
To match the position. Then, the surface coating film portion 21
The copper plate coil 9 is mounted on the center part of which is left a little. Next, the surface covering film portion 19 is bent at the solid line position 18, moved in the direction of the arrow, and superimposed on the copper plate coil 9.
At this time, the positions of the core insertion holes 20 of the surface covering film portion 19 and the other core insertion holes 10 and 22 match.

Therefore, when one side of the insulating film 16 coated with the adhesive is oriented upward, both surfaces of the copper plate coil 9 are covered with the film body 17 of the insulating film 16 and the surface covering film portions 19 and 21 are formed. Each can be attached. At this time, in the area near the core insertion hole 10 of the copper plate coil 9, the L-shaped concave portions 13 are provided at the respective corners at the edges thereof, so that the core insertion holes 20, 22 of the double-side coating film portions 19, 21 are provided. The films adhere to each other in the L-shape of the concave portion 13 at each corner portion of the edge portion. In the area near the outside of the copper plate coil 9, the surface covering film portions 19 and 21 are adhered to each other in a narrow ring shape except for the protruding portions of both terminals 12.
However, since the copper plate coil 9 is provided with the notch 15 at each corner of the outer edge thereof, the double-side coating film portion 1 is provided.
At the corners of the outer edges 9 and 21, the films adhere to each other in the form of a right-angled isosceles triangle, and the adhesion area also increases.

Therefore, the opposite side surfaces 2 of the copper plate coil 9
7 (27a, 27b) and inner peripheral side surface 28 of core insertion hole 10
Are folded in the direction of the arrow, respectively, and are overlapped and adhered to predetermined portions of the outer surface of the surface covering film portion 19, respectively. Then, a square plate-like bag 29 having a square core insertion hole 20 (22) in the center made of one insulating film coated with an adhesive on one side is completed, and the copper plate coil 9 is placed in the bag 29. Can accommodate. Each of the outer edge corners 30 (30a,... 30d) and the inner edge corners 31 (31a,... 31d) of the insulating film bag 29 has a joint of a large number of cutting lines constituting one insulating film 16. Exists as a weak point of the insulation performance.

However, by increasing the thickness by overlapping the bent pieces 23 on the opposing outer edges of the insulating film bag 29, the cutouts 15 provided on the edge of the copper plate coil 9 are also provided.
, It is possible to easily secure the insulation distances in two directions corresponding to the direction perpendicular to the surface of the copper plate coil 9 and the surface direction. Also, the core insertion hole 2 of the insulating film bag 29
In the same manner as described above, the bent pieces 24 are overlapped on the edges of the 0 (22) to increase the thickness, and the depth of each concave portion 13 provided at the edge of the core insertion hole 10 of the copper plate coil 9 also increases the insulation in two directions. The distance can be easily secured respectively. The insulating film 16 is appropriately selected from those having a required number of layers in accordance with the degree of insulation performance required by safety standards.

Accordingly, such an insulating film bag 29 is used.
When the planar transformer is manufactured using the copper plate coil 9 accommodated in the copper plate coil 9, the copper film coil 9 is interposed between the core plate inserted in the hole 10 and the cores arranged on both sides, and further adjacent to the copper plate coil 9 by the insulating film bag 29. In this case, the insulation distance between the coil and the coil can be easily secured. Then, the space required for insulating the copper plate coil 9 can be reduced, and the transformer can be reduced in size and thickness. Also, if the core insertion hole 10 is formed according to the shape of the core to be inserted and the projections 14 are provided at the center of each side of the edge of the core insertion hole 10, respectively, the projections are applied to the core from all sides. Thus, the copper plate coil 9 can be accurately positioned.

Therefore, if a rectangular flat plate-shaped lead portion is provided on the copper plate coil 9, the lead portion can be used as it is as the terminal 12, and an insulator such as a bobbin is not required, thereby reducing members and manufacturing costs. Will be possible. In addition, since the space conventionally required for insulation is partially unnecessary, the ring width of the copper plate coil 9 can be increased accordingly, the coil occupation area is increased, the electric resistance is reduced, and the heat generation and electric power of the coil are reduced. Loss can be reduced.

When a planar transformer is manufactured using the copper plate coil 9 accommodated in the insulating film bag 29 and the terminal 12, for example, four of the insulating film bag accommodating copper plate coils 9 are used. Then, as shown in FIG. 4, an E having both outer legs 32 (32a, 32b) and a middle leg 33 is provided.
The mold cores 34 (34a, 34b) are arranged vertically and the primary coil is alternately formed therebetween. The insulating film bag accommodating copper plate coil 9a (9a1, 9a2) and the insulating film bag accommodating the secondary coil. Copper plate coil 9b (9b1, 9b
b2), and all of the terminals 12 are bent into L shapes so that the primary coil and the secondary coil project in opposite directions.

Then, the middle legs 33 of the two E-shaped cores 34 are inserted into the core insertion holes 10, 20, 22 of the four insulating film bag-containing copper plate coils 9 to bring the tips into contact with each other. By contacting the tips of the 32 corresponding legs, a planar transformer 35 as shown in FIG. 5 can be assembled. Note that the corresponding terminals 1 of the two insulating film bag-containing copper plate coils 9 forming the primary side coil are formed.
2 are connected to each other, and the same applies to the secondary coil.

In the above embodiment, the insulating film bag 29 is used.
The notch 15 was provided at each corner of the outer edge of the copper plate coil 9 in order to secure an insulation distance away from the weak point 30 of insulation performance at each corner of the outer edge of the E-shaped core. However, it is not necessary to provide such a notch as long as the length is shorter than the length of the outer edge portion arranged on the outer leg side of the copper plate coil and the insulation distance between the outer leg and the outer leg can be ensured.

In the above embodiment, two E-shaped cores 34 are used as the cores constituting the planar transformer 35. However, a core having another shape such as a combination of an E-shaped core and an I-shaped core is appropriately used. be able to.

[0022]

According to the present invention described above, claim 1
In the described invention, even if there are seams of a number of cutting lines constituting one insulating film at each inner edge corner facing the core insertion hole of the insulating film bag as weak points of the insulating performance, In order to cover the inner peripheral side of the core insertion hole of the conductive plate coil accommodated in the insulating film bag, bent pieces are respectively protruded at the edge of the core insertion hole of the film covering one surface of the insulating film, and The insulation distance is easily secured by increasing the thickness by overlapping the bent pieces on the edge of the core insertion hole of the film bag and by the depth of each recess provided at the edge of the core insertion hole of the conductive plate coil. it can.

Therefore, when a planar transformer is manufactured using an insulating film bag-containing conductive plate coil, insulation between the conductive plate coil and the core inserted into the hole and between the conductive plate coil and an adjacent coil by the insulating film bag. The distance can be easily secured respectively. In addition, the space required for insulating the conductive plate coil can be reduced, and the transformer can be reduced in size and thickness. Also, if the core insertion hole of the conductive plate coil is formed in conformity with the core shape and the protrusions are provided at the edges of the core insertion hole, the protrusions are applied to the core from four directions to form the conductive plate coil. Positioning can be performed accurately.

Therefore, if the lead portion is provided in the conductive plate coil, the lead portion can be used as a terminal as it is, and an insulator such as a bobbin is not required, and the members and the manufacturing cost can be reduced. In addition, since the space conventionally required for insulation is partially unnecessary, it is possible to increase the ring width of the conductive plate coil, thereby increasing the area occupied by the coil, reducing the electric resistance, and generating heat and electricity of the coil. Loss can be reduced.

According to the second aspect of the present invention, the seam of a large number of cutting lines constituting one insulating film is present at each corner of the outer edge of the insulating film bag as a weak point of the insulating performance. Also, in order to cover the opposing outer surfaces of the conductive plate coil housed in the insulating film bag, bent pieces are respectively projected on the corresponding outer edges of the film portion for covering one surface of the insulating film, and the insulating film bag is formed. The insulation distance can be easily secured by increasing the thickness by overlapping the bent pieces on the opposing edges, and by the depth of each notch provided in the edge of the conductive plate coil.

[Brief description of the drawings]

FIG. 1 is a plan view of a copper plate coil housed in an insulating film bag used for a planar transformer to which the present invention is applied and terminals drawn from the copper plate coil.

FIG. 2 is a plan view of the copper plate coil and its terminals.

FIG. 3 is a perspective view showing a positional relationship between the copper plate coil and an insulating film immediately before packaging.

FIG. 4 shows the copper plate coil accommodated in the insulating film bag as 4
It is a perspective view which shows arrangement | positioning of each component at the time of the assembly of the planar transformer using two pieces and two E type cores.

FIG. 5 is a perspective view after the planar transformer is assembled.

FIG. 6 is a perspective view showing an arrangement of respective parts when assembling a conventional planar transformer.

FIG. 7 is a plan view showing a modified example of a copper plate coil and terminals thereof used in the planar transformer.

[Explanation of symbols]

9: copper plate coil 10, 20, 22 ... core insertion hole 11
... Slit 12 ... Terminal 13 ... Recess 14 ... Protrusion 1
5: Notch 16: Insulating film 17: Film body 18, 25, 26 ... Bending point 27: Opposite outer surface 28: Inner peripheral surface 29: Insulating film bag
30, 31: weakness of insulation performance 32: outer leg 33: middle leg 34: E-shaped core 35: planar transformer

Claims (2)

[Claims] 1. A conductive plate coil in which a conductive plate is formed in at least a part of a coil in the shape of a flat plate ring, a rectangular core insertion hole is formed in the ring, and a slit for cutting a part of the ring is provided. In the planar transformer using the above, at the edge of the core insertion hole of the conductive plate coil, each corner of the edge is provided with a concave portion which recedes outward, and the center of each side of the edge is provided. Are made to project inward, and the conductive plate coil is housed in a flat ring-shaped bag with a square core insertion hole in the center made of one insulating film coated with adhesive on one side. A planar transformer, wherein insulating films are attached to both sides of the conductive plate coil. 2. A conductive plate in which a conductive plate is formed in at least a part of a coil in the shape of a rectangular flat plate ring, a rectangular core insertion hole is formed in the ring, and a slit for cutting a part of the ring is provided. In a planar transformer using a coil, a recess is provided at each of the corners of the core insertion hole of the conductive plate coil, and each corner of the edge is provided with a concave portion that recedes outward, and the center of each side of the edge is provided. Each part is a protruding part that protrudes inward, and furthermore, a notch is provided at each corner of the outer edge of the conductive plate coil, and the conductive plate coil is coated with an adhesive on one side by one sheet of insulation. A planar transformer, wherein the planar transformer is housed in a rectangular flat ring-shaped bag provided with a square core insertion hole in the center of a film, and an insulating film is attached to both sides of the conductive plate coil.