JPH07297050A - Laminated sheet transformer - Google Patents

Abstract

PURPOSE:To obtain a laminated sheet transformer whose structure is capable of miniaturization. CONSTITUTION:A laminated sheet transformer 10 includes a laminate 12, which is formed by stacking insulating sheets on which a spiral conductor pattern is formed. A lead-out part 18a is formed by leading out the end portion of the conductor pattern. A dummy lead-out part 22 not connected with the conductor pattern is formed. A terminal 24 is formed by stacking together the lead-out part 18a and the dummy lead-out part 22. A core 26a and a core 26b are made to abut against each other from both sides of the laminate 12. An insulating sheet 14 of the lowermost layer of the laminate 12 is made larger than the other insulating sheets, and bent from the end surface of the laminate 12 toward the bottom surface.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a laminated sheet transformer, and more particularly to, for example, a laminated sheet transformer obtained by laminating insulating sheets having conductor patterns for forming windings.

[0002]

2. Description of the Related Art FIG. 8 is a perspective view showing an example of a conventional laminated sheet transformer, and FIG. 9 is a side view thereof. The laminated sheet transformer 1 includes a laminated body 2 in which a plurality of insulating sheets are laminated. For example, a spiral conductor pattern is formed on the insulating sheet, and the end portion thereof is drawn out. A primary winding and a secondary winding are formed by these conductor patterns. The ends of the drawn out conductor pattern are bent to form the terminals 3. Further, the core 4 is inserted into the laminated body 2 so as to penetrate the central portion of the conductor pattern, thereby forming a closed magnetic circuit.

The laminated sheet transformer 1 is mounted on, for example, a printed circuit board or the like. At this time, the terminal 3 is connected to the electrode of the printed board by soldering or the like. Therefore, the conductor pattern on the insulating sheet and the electrode of the printed circuit board are connected via the terminal 3.

[0004]

A magnetic material is used as the material of the core used in the laminated sheet transformer.
A commonly used magnetic material is a conductive material. Therefore, the insulation between the terminals and the core must be ensured so that the primary winding and the secondary winding are not electrically connected via the core. Therefore, it is necessary to increase the lengths A and B of the laminated body portion outside the core and increase the distance between the core and the terminal. For this reason, it has been difficult to reduce the size of the laminated sheet transformer.

Therefore, a main object of the present invention is to provide a laminated sheet transformer having a structure which can be downsized.

[0006]

According to the present invention, a plurality of insulating sheets to be laminated, a winding portion made of a conductor pattern formed on the insulating sheet, a terminal drawn from the winding portion, and a winding portion are provided. A laminated sheet transformer including a core forming a magnetic path for a magnetic flux generated by, and insulating between the terminals and the core by bending an insulating sheet from the end surface of the core toward the bottom surface. In order to obtain such a laminated sheet transformer, the outermost insulating sheet of the laminated insulating sheets can be formed larger than the other insulating sheets, and the outermost insulating sheet can be bent from the end face to the bottom face of the core. .

[0007]

Function: By bending the insulating sheet from the end surface of the core toward the bottom surface, the surface portion of the core is insulated.
This increases the creepage insulation distance between the terminal and the core.

[0008]

According to the present invention, since the creepage insulation distance between the terminal and the core becomes large, a large insulation property can be obtained. Therefore, even if the laminated body portion exposed outside the core is made small, sufficient insulation can be obtained between the terminal and the core, and conduction between the windings can be prevented. Therefore, the laminated sheet transformer can be downsized.

The above-mentioned objects, other objects, features and advantages of the present invention will become more apparent from the following detailed description of the embodiments with reference to the drawings.

[0010]

1 is a perspective view showing an embodiment of the present invention, FIG. 2 is a side view thereof, and FIG. 3 is an exploded perspective view thereof. The laminated sheet transformer 10 includes a laminated body 12.
The laminated body 12 is formed by laminating a plurality of insulating sheets 14 on which conductor patterns are formed. As the insulating sheet 14, for example, a high-voltage and flexible insulator such as a polyimide film or a polyester film is used. A hole 16 for inserting the core is formed in the center of each of the insulating sheets 14.

In this laminated sheet transformer 10, the winding portions are formed by connecting the conductor patterns.
Then, the transformer is formed by stacking the plurality of winding portions. Here, a pair of insulating sheets forming one winding portion will be described.

As shown in FIG. 4, a hole 1 is formed on one main surface of the upper insulating sheet 14 of the pair of laminated insulating sheets.
A spiral conductor pattern 18 is formed around the circumference 6.
One end of the conductor pattern 18 is drawn out to the outside of one end of the insulating sheet 14 in the width direction to form a drawn portion 18a. Further, the other end portion 18 b of the conductor pattern 18 has a through hole 2 formed in the vicinity of the hole 16 of the insulating sheet 14.
It is formed so as to cover 0. Further, a plurality of dummy lead-out parts 22 are formed on one main surface of the insulating sheet 14. These dummy lead-out portions 22 are drawn out from both ends of the insulating sheet 14 in the width direction. The conductor pattern 18 and the plurality of dummy lead portions 22 are simultaneously formed by a method such as etching or printing.

As shown in FIG. 5, a spiral conductor pattern 18 is formed around the hole 16 on one main surface of the lower insulating sheet 14 of the pair of insulating sheets. One end of the conductor pattern 18 is drawn out to the outside of one end of the insulating sheet 14 in the width direction to form a drawn portion 18a. This lead-out portion 18a is one of the above-mentioned dummy lead-out portions 22.
Insulation sheet 14 formed at a position corresponding to
It is formed so as to be adjacent to the drawn-out portion 18a formed in. The other end 18b of the conductor pattern 18 is formed at a position corresponding to the above-mentioned through hole 20. Further, a plurality of dummy lead-out portions 22 are also formed on the one main surface of the insulating sheet 14. These dummy drawers 22
Are formed at positions corresponding to the lead-out portions 18a and the dummy lead-out portions 22 of the conductor pattern 18 of the insulating sheet 14 shown in FIG.

These insulating sheets 14 are laminated so that the lead-out portions 18a of the conductor pattern 18 and the dummy lead-out portions 22 overlap each other. And the two conductor patterns 18
The other end portion 18b is connected via the through hole 20, for example, by spot welding. Therefore,
One winding portion is formed between the lead-out portions 18a of the two conductor patterns 18 formed on the two insulating sheets 14.

Similarly, a conductor pattern and a dummy lead portion which will be another winding portion are also formed on one main surface of the other insulating sheet 14. A primary winding and a secondary winding are formed by the plurality of winding portions. No conductor pattern is formed on the uppermost insulating sheet. Further, the lowermost insulating sheet 14 is formed larger than the other insulating sheets 14. In particular, the bottommost insulating sheet 14
Are formed to be larger than the other insulating sheets 14 in the direction in which the lead-out portion 18a and the dummy lead-out portion 22 are formed.

The plurality of insulating sheets 14 are the conductor patterns 1
The lead-out portion 18a of 8 and the dummy lead-out portion 22 are laminated so as to overlap with each other to form the laminated body 12. Each of the overlapping drawn-out portions has its intermediate portion bent downward in a direction orthogonal to the main surface of the insulating sheet 14, and its tip portion bent outward in a direction substantially parallel to the main surface of the insulating sheet 14. Furthermore, the overlapped lead-out portions are joined by, for example, spot welding, soldering, or caulking to form the terminals 24. That is, terminal 2
Reference numeral 4 denotes a first portion 24a that extends downward and that intersects with the main surface of the insulating sheet 14 outside the insulating sheet 14, and a first portion 24a.
Second portion 24b extending outward from the portion 24a in a direction substantially parallel to the main surface of the insulating sheet 14.

Cores 26a and 26b are provided above and below the laminated body 12, respectively. The upper core 26a is the laminated body 12
Includes a flat plate portion 28a having a main surface having a width slightly narrower than the upper surface of a. The flat plate portion 28a is formed with a middle foot portion 30 extending downward at the center thereof, and outer foot portions 32a, 32a extending downward at both ends in the longitudinal direction thereof. The lower core 26b also includes a flat plate portion 28b,
Outer legs 32b, 32b extending upward are formed at both ends of the flat plate portion 28b in the longitudinal direction. Then, the stacked body 12 is placed on the lower core 26b. Further, the middle leg portion 30 of the upper core 26a is butted against the flat plate portion 28b of the lower core 26b through the hole 16 of the laminated body 12. At the same time, the outer legs 32a, 32 of the upper core 26a
a is butted against the outer leg portions 32b, 32b of the lower core 26b. The upper and lower cores 26a and 26b are
For example, they are fixed by winding an adhesive tape around them. In addition, the second portion 24b of the terminal 24 is
The lower surface is formed to be substantially flush with the lower surface of the lower core 26b.

The lowermost insulating sheet 14 is the lower core 2
It is bent to the end surface of 6b and further to the bottom surface of the core 26b. The folded insulating sheet 14 is bonded to the core 26b. With this insulating sheet 14,
Creepage insulation distances A and B between the terminal 24 and the core 26b
Can be increased, and a large insulating property can be obtained. Therefore, even if the first portion 24a of the terminal 24 and the core 26b are close to each other, the insulating sheet 14 ensures the insulating property and prevents the conduction between the primary winding and the secondary winding. it can.

This laminated sheet transformer 10 has terminals 24.
It can be surface-mounted on the printed circuit board by soldering the second part 24b of the electrode to the electrode on the printed circuit board. Therefore, the primary winding and the secondary winding are connected to the electrodes of the printed circuit board via the terminals 24.

In this laminated sheet transformer 10, the terminals 2
Since the lower surface of the second portion 24b of No. 4 is substantially in the same plane as the lower surface of the lower core 26b, and the lower surface of the terminal 24 and the lower surface of the core 26b can contact the surface of the printed circuit board, It can be firmly mounted.

In this laminated sheet transformer 10, the core 2
The insulating sheet 14 bent from the end surface of 6b toward the bottom surface ensures the insulation between the terminal 24 and the core 26b. Therefore, it is necessary to increase the size of the laminated body 12 portion outside the cores 26a and 26b. Absent. That is, terminal 2
4 can be brought close to the core 26b, and the laminated sheet transformer 10 can be downsized.

In the above-described embodiment, the dummy lead-out portion 22 is superposed on the lead-out portion 18a composed of one end of the conductor pattern, but the dummy lead-out portion 22 may not be formed. In this case, the terminals 24 associated with the conductor pattern 18
Is composed of only the lead-out portion 18 a of the conductor pattern 18. Further, the dummy electrode 22 does not have to be formed entirely, and a part thereof may be formed.

In addition, in the above-described embodiment, the second terminal of the terminal 24 is used.
The portion 24b is bent outward, but may be bent inward as shown in FIG. further,
As shown in FIG. 7, the tip of the terminal 24 may not be bent. Further, in the above-described embodiment, the lower surface of the second portion 24b of the terminal 24 and the lower surface of the core 26b are substantially in the same plane, but these lower surfaces do not necessarily have to be in the same plane.

Further, in the above-described embodiment, the terminals 24 are formed on both sides of the laminated body 12 in the width direction.
May be formed on only one side or all side surfaces of the laminated body 12. Further, in the above-described embodiment, the middle foot portion 30 is formed only on one core 26a, but both cores 26a,
A middle foot portion may be formed on 26b. Further, the outer foot portion 32b of the core 26b may not be formed, and in that case, the E-shaped core and the I-shaped core are combined.

[Brief description of drawings]

FIG. 1 is a perspective view showing an embodiment of the present invention.

FIG. 2 is a side view of the laminated sheet transformer shown in FIG.

FIG. 3 is an exploded perspective view of the laminated sheet transformer shown in FIG.

FIG. 4 is a plan view showing one of insulating sheets used in the laminated sheet transformer shown in FIG.

5 is a plan view showing another insulating sheet laminated on the insulating sheet shown in FIG. 4. FIG.

FIG. 6 is a side view showing a modified example of the present invention.

FIG. 7 is a side view showing another modification of the present invention.

FIG. 8 is a perspective view showing an example of a conventional laminated sheet transformer.

9 is a side view of the conventional laminated sheet transformer shown in FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Laminated sheet transformer 12 Laminated body 14 Insulating sheet 18 Conductor pattern 18a Leading portion 22 Dummy leading portion 24 Terminal 26a Core 26b Core

Claims (2)

[Claims] 1. A plurality of insulating sheets to be laminated, a winding portion formed of a conductor pattern formed on the insulating sheet, a terminal drawn from the winding portion, and a magnetic flux generated by the winding portion. A laminated sheet transformer including a core forming a magnetic path, wherein the insulating sheet is bent from an end surface of the core toward a bottom surface to insulate between the terminal and the core. 2. The outermost insulating sheet of the laminated insulating sheets is formed larger than the other insulating sheets, and the outermost insulating sheet is bent from the end surface of the core toward the bottom surface. 1 laminated sheet transformer.