JPH08316060A - Multilayer transformer - Google Patents

Abstract

PURPOSE: To provide a thin, small-sized multilayer transformer being employed in electronic apparatus with no problem of insulation or performance at low price. CONSTITUTION: Since all end face parts 5 of winding 2 are fused and integrated, except the lead-out part, and the creeping face is eliminated, problems of insulation are eliminated and a thin, small-sized multilayer transformer conformable to various safety regulations is obtained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a laminated transformer using laminated coils used in various electronic devices.

[0002]

2. Description of the Related Art In recent years, in order to meet the technical needs for higher frequency, smaller size, and thinner transformer, a printed coil laminated transformer using a print etching technique, a transformer having a punched coil laminated structure formed by punching a copper plate, or A spiral coil laminated structure transformer in which electric wires are formed in a spiral shape has been developed with a focus on pursuing low loss technology or structure-based optimum design technology.

In reality, in addition to the above technical needs, there is a strong demand for thorough cost reduction and high safety as a background of the times, and without this point, practical use is not possible. There is.

A small and thin laminated transformer compatible with high frequencies,
In order to provide at low cost and high safety, technically low loss technology, optimal shape / structure design technology, high safety insulation technology, etc. are required. At present, the development of highly safe insulation technology, which is most suitable for shaping, is delayed.

In addition, there is an increasing demand for smaller and thinner power supplies, low cost and high safety, and it is no exaggeration to say that the key part for differentiation is a transformer.

A thin laminated transformer using laminated coils is generally shown in FIGS.

A conventional transformer will be described below with reference to FIGS. 12 to 14, 1 is a magnetic core, 2 is a winding, 3 is an insulating paper, and 4 is a coil case.

The configuration will be described with reference to FIG. Winding 2 and insulating paper 3 formed by spirally winding an electric wire
Are alternately laminated to complete a laminated coil, and then the thin core transformer main body is completed by incorporating the magnetic core 1 forming a closed magnetic circuit from the direction in which the coils are laminated. The winding 2 may be a punched coil made by punching a thin plate conductor. FIG. 13 shows a cross-sectional view of a thin laminated transformer in which the winding 2 is laminated in three layers.
In FIG. 13, two primary windings 2a are used, and the secondary windings 2b are alternately laminated. FIG. 12 is a sectional view of a thin laminated transformer using the coil case 4 as another conventional example. Here, after the primary winding 2a, the secondary winding 2b, and the insulating paper 3 are laminated in the coil case 4,
The magnetic core 1 is incorporated to complete the thin laminated transformer body.

[0009]

However, in the above-described conventional configuration of FIG. 13, the primary winding 2a and the secondary winding 2b have a coil in which the insulating paper 3 is inserted between the respective windings. Guarantee of insulation at the end face is performed by securing a creepage distance. Furthermore, the primary and secondary windings 2a, 2
The same applies between b and the magnetic core 1. As a result, in the part A in the figure, a defective insulation between windings occurs due to insufficient distance, and
Insulation failure part between the magnetic core 1 and the winding wire 2 occurs in the area of 1, and variations in electrical performance occur, resulting in a loss in quality.

As a method for remedying such a problem as much as possible, there is also a method of accommodating a laminated coil in a coil case 4 to maintain insulation as shown in FIG. 12, and an insulation failure portion B between the magnetic core 1 and the winding 2 is improved. However, it is difficult to secure the insulation at the portion A in the figure, and the problem of quality loss due to variation in electric performance has not been solved.

As described above, the common problem of FIGS. 12 to 14 is that the creepage distance is secured as a means for securing insulation, and this distance is set to a large value for safety design. Thinning cannot be achieved.

As another insulating technique (not shown), a creeping distance is relaxed by adding sealing means such as resin casting or resin molding to the basic structure of FIGS. 12 to 13 to strengthen the insulation. However, there are problems in that it is very difficult to control the generation of voids in the resin, quality is maintained, and cost is reduced.

Further, as an insulating technique for sealing the end face portion of the coil, which is generally called a printed coil, a method of forming a coil by etching copper foil on the insulating paper and then pasting the upper and lower insulating papers with an adhesive, integrally molding There is also a method of sealing the upper and lower insulating papers by a vacuum heat pressing method using a thermosetting resin like a printed multilayer board coil, but there is also a limit to the adhesive force between the resin and the adhesive and the insulating papers. There are problems such as difficulty in management, and it cannot be said that it is sufficient to maintain quality and reduce costs.

The present invention solves the above-mentioned problems, and by presenting a new type of high-safety insulating means that is most suitable for a compact and thin structure that has never existed in the past, there is no problem in insulation and a problem in performance occurs. It is an object of the present invention to provide a laminated transformer that eliminates the above and is also compatible with the safety standards of each country at low cost.

[0015]

In order to solve the above-mentioned problems, the present invention integrates upper and lower insulating layers by fusion or the like on the other end face portion excluding the end face portion on the side where the lead wire of the winding is pulled out. A thin flat coil characterized by being closed by using at least one of the primary and secondary windings, and
The secondary winding and the secondary winding are laminated so that the lead-out directions of the lead-out wires are opposite to each other in the left and right directions to form a laminated coil, and a magnetic core forming a closed magnetic circuit is incorporated from the direction in which the coils are laminated. It is a thing.

[0016]

With the above construction, since there is no creeping surface other than the lead-out portion of the winding wire, it becomes a thin flat coil completely covered with insulating paper, and it is a laminated transformer with stable performance without insulation problems. is there.

[0017]

【Example】

(Embodiment 1) A first embodiment, which is an embodiment of the laminated transformer of the present invention, will be described below with reference to FIGS.

Basically, in FIGS.
The same components as those in the related art shown in FIG. 14 are denoted by the same reference numerals, and detailed description will be omitted. In FIG. 1, a major difference from the conventional example is that the primary winding 2a and the secondary winding 2b have an end face fusion portion 5 on the end faces.

First, the structure of the thin flat coil will be described with reference to FIG. In this embodiment, the self-bonding winding is wound in a spiral shape, and the winding 2 is sandwiched from above and below with the insulating paper 3 having the middle leg magnetic leg insertion hole portion 7 formed therein, and then the winding 2 is wound. All the other end face portions except the end face portion on the side where the lead wire 6 is pulled out are integrated and closed by a method such as fusion bonding. Examples of the fusing method include a heat fusing method, an ultrasonic fusing method, and an ultrasonic pressing method, but another method may be used as long as the end face portions can be integrated. The hole 7 for inserting the middle leg magnetic leg may be formed by punching after fusion of the end faces using insulating paper without holes.

There are various methods of manufacturing the winding 2, such as a method of winding it in a spiral shape and then hardening it with resin or the like, a method of punching a conductive plate to manufacture, and other various methods. There is no need to limit it.

The thin flat coils manufactured in this manner are laminated so that the lead wires of the primary winding 2a and the secondary winding 2b are drawn out in the left and right directions, and from the direction in which the coils are laminated. The magnetic core 1 forming the closed magnetic circuit is incorporated to complete the laminated transformer.

FIG. 1 shows a diagram for explaining the laminated structure of this laminated transformer. FIG. 1 shows X in FIG. 14 showing a conventional example.
Since the cross section in the same direction as the -X 'direction is shown, the end faces of the primary winding 2a and the secondary winding 2b are all completely closed by the end face fusion portion 5.

As described above, according to this structure, since there is no creeping surface other than the lead-out portion of the winding 2, the thin flat coil is completely covered with the insulating paper 3 and the problem of insulation is eliminated. There is no need to set a large creepage distance as in. In addition, the difficulty in management due to the method of sealing with resin, adhesive, etc. or the anxiety of long-term reliability due to the limit of adhesive strength is eliminated, quality can be maintained easily, and as a result, productivity can be improved, It is possible to provide an unprecedentedly safe, inexpensive, and thin laminated transformer.

In the above description, both of the primary winding 2a and the secondary winding 2b are provided with the end face fusion-bonding portion 5, but it is safe to use either one of the windings when the voltage is extremely low. If there is no need at all, the end face fusion-bonding portion 5 may be provided on only one of the windings, if necessary.

(Second Embodiment) A second embodiment of the present invention will be described below with reference to FIG.

In FIG. 3, a portion different from the first embodiment shown in FIG. 1 is a flat plate formed by processing an insulating film by thermoforming etc. on at least a part of the inner and outer peripheral end faces to form a convex portion having a predetermined width and height. -Shaped coil spacer, that is, the recessed spacer 8 also serves as insulating paper, and the recessed spacer 8 has a coil (primary winding 2a or secondary winding 2b) in the recess.
This is the point where

According to this structure, the windings 2a and 2b are housed in the recesses of the coil spacer 8, the positional relationship between the windings is stable, and variations in performance such as electrical performance are reduced. Further, since the concave and convex portion of the concave spacer 8 can be used as a reference, the dimension and position accuracy of the end face fusion portion 5 can be obtained regardless of whether the forming process of the middle leg magnetic leg insertion hole portion 7 is before or after the end face fusion process. This facilitates the process, improves the degree of freedom in the process knitting, reduces the set value of the end face fusion-bonding portion 5, and achieves further miniaturization. The unique effect as described above can be obtained in addition to the first embodiment.

(Embodiment 3) A third embodiment of the present invention will be described below with reference to FIG.

FIG. 4 is a view showing a laminated structure of thin flat coils according to the third embodiment of the present invention. 4 is different from the second embodiment in FIG. 3 in that concave spacers 8 are used as upper and lower insulating layers and the concave spacers 8 are fitted therein.

According to this structure, since the upper and lower insulating layers also have irregularities, it is easy to stack the thin flat coils, and since the same insulating material can be used, the number of parts can be reduced. It is obtained in addition to the second embodiment.

(Fourth Embodiment) A fourth embodiment of the present invention will be described below with reference to FIG.

5 is different from FIG. 3 in that a resin molded spacer 8a formed by resin molding is used as the concave spacer.

According to the structure shown in FIG. 5, since the molding is performed by the mold, it is possible to form a thin and fine spacer, the positional accuracy of the winding becomes very good, and the variation in performance can be further reduced. The effect of reducing the cost of the spacer can be achieved by increasing the number of spacers.

In FIG. 5, one resin-molded spacer 8a is used in the lower part of the winding 2, but if it is used in the upper and lower sandwiches as in FIG. 4, the same effect as that of the third embodiment can be obtained. It goes without saying that it will be done.

(Fifth Embodiment) A fifth embodiment of the present invention will be described below with reference to FIGS.

6 and 9 show the conventional example shown in FIG.
XX 'direction, and FIGS. 7 and 8 show sectional views in the same direction as the YY' direction. 1 to 5 in FIGS. 6 and 7.
Is different from that of the first embodiment in that the primary winding 2a is housed in a concave spacer 8 of three layers, and the upper part is sandwiched by three layers of insulating paper 3 and the fusion width of the end face fusion portion 5 is 0.4m
It is a point that is m or more. In addition, FIG. 8 is shown in FIGS.
On the other hand, the primary winding 2a has two insulating layers. Furthermore, FIG. 9 has a configuration in which the insulating layer of the secondary winding 2b is removed from the configurations of FIGS.

Before describing the effects of the above configuration, the safety standard will be briefly described. Currently, as a representative international standard for controlling the safety of the insulation type transformer, IEC65 that regulates household electronic devices such as TV and VTR, and IEC950 that regulates office office information devices such as OA devices.
And the creepage distance, thickness, etc. are specified in detail.

As the insulation method between the primary winding and the secondary winding of the insulation transformer, there are a method of performing reinforced insulation and a method of performing double insulation which is a concept of performing basic insulation and auxiliary insulation in double. ) Shows the outline of the standard.

[0039]

[Table 1]

From Table 1, it can be understood that the regulation items for the primary and secondary windings are the thickness and the creepage distance.

In Table 1, the thickness of the primary and secondary windings is 2 in the case of the three-layer insulation structure of IEC65.
If the layer satisfies the specified withstand voltage test, the thickness can be made unquestionable. In the case of the two-layer insulation structure of IEC950, if the specified withstand voltage test is satisfied for one layer, the thickness can be made unquestioned. I quote.

In general, since there is a creeping surface between the primary and secondary windings, windings having a creeping surface to reduce this creeping distance are conventionally performed in order to achieve miniaturization. We have been studying the means to reduce the distance by bonding the end face of the wire with adhesive, filling with resin, etc. I have a new idea to make effective use of regulations.

FIG. 6 showing this embodiment is a cross section in the direction in which the lead wire is not drawn out. Since the upper and lower sides of the primary winding 2a are formed by three layers of insulating paper 3 and concave spacers 8, The winding facing surfaces of the secondary winding 2a and the secondary winding 2b have a three-layer insulating structure. Further, since the end faces are fused and integrated, there is no creeping surface. Furthermore, the width of the fused portion 5 is 0.4 m
Since it is m or more, the stipulation of the thickness of the reinforced insulation can be applied to this portion. As described above, since the structure does not have a creeping surface in the cross-sectional direction in FIG. 6, it is possible to comply with the thickness regulation for reinforced insulation of IEC65.

On the other hand, FIG. 7 is a cross section in the direction in which the lead wire 6 is pulled out. In the cross section in this direction, since the primary winding 2a and the secondary winding 2b both have a creeping surface between them and the lead wire 6, the regulation of the creepage distance is applied only to this lead portion. In FIG. 7 of this embodiment,
Since the upper and lower sides of the secondary winding 2b are sandwiched by one layer of insulating paper 3 and one layer of the concave insulating spacer 8 and the end face portions are fused, the secondary winding 2b has a structure in which basic insulation is applied. Has become. Therefore, the standard of the double insulation structure can be applied between the primary lead wire 6a and the secondary winding 2b, and if the distance of the creeping surface L ₁ in FIG.
The creepage distance standard for auxiliary insulation of IEC65 can be satisfied. Further, between the secondary lead wire 6b and the primary winding 2a, it is not necessary to consider the distance of the lead portion because the upper and lower sides of the primary winding 2a and the end face portion have a reinforced insulating structure.

There is also a restriction on the distance to the transformer peripheral parts depending on the handling of the magnetic core constituting the insulating transformer, and an example of this is shown in (Table 2).

[0046]

[Table 2]

From Table 2, if the magnetic core is accessible, that is, if the magnetic core is treated as a secondary, the distance from the secondary parts around the magnetic core may be 0 mm. This means that the secondary parts can be placed close to each other, and high-density mounting of the power supply can be achieved.

In the structure of FIG. 6, since the primary winding 2a has a reinforced insulating structure, the magnetic core 1 can be treated as a secondary. In the configuration of FIG. 7, if the creepage distance L ₂ between the primary lead wire 6a and the magnetic core 1 in the figure is secured to be 6.0 mm or more, the IEC65 reinforced insulation can be satisfied, and the magnetic core 1 is treated as a secondary treatment. When mounting this transformer as a power supply,
The secondary component can be brought close to the magnetic core 1, and the high density mounting can be easily achieved.

As described above, according to the configurations shown in FIG. 6 and FIG.
Since the secondary winding 2a has a reinforced insulation structure that does not have any creepage with respect to the secondary winding 2b and the magnetic core 1 except for the creeping portion of the primary lead wire 6a, the thickness regulation in the safety standard can be applied, IE only on the surface of the lead wire 6a
It is only necessary to consider the creepage distance required for C65 compliance, and it is possible to provide an innovative safety standard compliant structure that has a great effect in terms of downsizing.

FIG. 8 shows another embodiment showing a structure conforming to IEC950, in which the upper and lower parts of the primary winding 2a are separated by 2 in comparison with FIG.
The only difference is that the insulating layer 3 and the concave spacer 8 are formed, and L ₁ and L ₂ are 8.0 mm and 4.0, respectively.
If it is set to be equal to or greater than mm, the same effect as that of the embodiment of FIGS. 6 and 7 can be obtained.

Further, FIG. 9 is different from FIG. 6 in that the secondary winding 2b
The primary difference is that the secondary winding 2b does not have a basic insulation structure, but in this case as well,
The secondary winding 2a has a reinforced insulation structure except for the portion of the lead wire with respect to the secondary winding 2b and the magnetic core 1. Therefore, only the lead wire portion may be set in consideration of the creepage distance of the reinforced insulation. . In other words, if IEC65 is 6mm or more, IE
With C950, if a predetermined creepage distance of 8 mm or more is secured, the same effect as in FIGS. 6 to 8 can be obtained.

In the fifth embodiment, the size of the end face fused portion is set to 0.4 mm or more, but this is quoted from the current safety standard. It goes without saying that it is necessary to set the thickness to a predetermined thickness that can comply with the safety standard at that time.

As described above, FIGS. 6 to 9 of the fifth embodiment of the present invention.
According to the configuration shown in Fig. 1, the primary winding 2a has a reinforced insulation configuration that does not have any creepage with respect to the secondary winding 2b and the magnetic core 1 except for the creeping portion of the primary lead wire 6a. Since the thickness regulation in the standard can be applied, it is sufficient to consider the distance required for safety standard compliance only in the creepage part of the primary lead-out wire 6a, and a safety standard compliant structure with a great effect in terms of downsizing is provided. It will be possible. Also, considering the creepage distance from the magnetic core 1, when the power supply of this transformer is mounted, the secondary component can be brought close to the magnetic core 1 and the effect that the high density mounting can be easily achieved can be obtained. Great value is created especially when constructing a laminated transformer.

(Sixth Embodiment) A sixth embodiment of the present invention will be described below with reference to FIG.

10 is different from the fifth embodiment shown in FIG. 6 in that the upper insulating paper 3 and the lower insulating layer 8 of the winding are formed of a plurality of layers, and the periphery of the end face fusion portion 5 is strengthened. Adhesive resin 9 has a predetermined size or more, 0.4 mm in this embodiment.
The above is the point of mold sealing.

According to this structure, the periphery of the end face fusion-bonded portion 5 is sealed with the strongly adhesive resin 9, and a predetermined thickness of 0.4 mm or more necessary for auxiliary insulation in safety standards can be secured. Since the end face fusion portion 5 is integrally closed, the end face fusion portion 5 can be regarded as basic insulation without securing the dimensions of the end face fusion portion as in the fifth embodiment. The surrounding area has a double insulation structure (basic + auxiliary insulation), and it can be a structure that can comply with safety standards. This eliminates the need for dimensional control and the like in the manufacturing process of the end face fusion-bonding portion 5 and makes it possible to provide a double safety structure, which brings about a new effect that a higher safety structure can be realized.

FIG. 11 shows another embodiment of the sixth embodiment of the present invention, in which a concave shape for accommodating the winding 2 is provided in order to further ensure the size of the periphery of the end face fusion portion 5. In this example, after the spacer and the insulating paper 3 are laminated, the end face dimension L is flattened by a dimension capable of ensuring a predetermined thickness and then the periphery thereof is fused.

(Embodiment 7) A sixth embodiment of the present invention will be described below.

The seventh embodiment of the present invention has the structure of the sixth embodiment by molding the entire laminated coil.

According to this structure, after the coils are laminated, the entire laminated coil can be sealed, so that the treatment of the periphery of the end face fusion portion 5 can be performed only once, the manufacturing process can be simplified, and the actual productivity is improved. The effect is obtained.

The molding method may be a resin casting method, an injection molding method, or any other method as long as the periphery of the end face fused portion 5 can be sealed. Needless to say, it is preferable to use a method such as vacuum casting or vacuum molding that can reduce the occurrence of voids in the resin.

(Embodiment 8) As described above, Embodiments 1 to 7 of the present invention.
If a laminated transformer like the one shown in the figure is mounted on the power supply unit, higher density mounting is possible as a power supply. A power supply that meets the needs of the times such as compactness, high safety, and high quality that cannot be obtained with conventional thin laminated transformers. The device can be provided at low cost.

[0063]

As described above, the present invention is characterized in that the upper and lower insulating layers are integrated and closed by fusion or the like at the other end face portion except the end face portion on the side where the lead wire of the winding is pulled out. The thin flat coil is used for at least one of the primary and secondary windings, and the primary and secondary windings are laminated so that the lead-out directions of the lead wires are opposite to each other to form a laminated coil. However, since the magnetic core forming the closed magnetic circuit is incorporated from the direction in which the coils are laminated, (1) There is no problem in insulation except for the lead-out portion of the winding.

(2) It is not necessary to set a large creepage distance except for the winding lead-out portion, and the size can be reduced.

(3) The quality can be maintained easily and the productivity is improved. (4) Higher safety can be achieved.

Further, a flat coil spacer formed by forming a convex portion having a predetermined width and height on at least a part of the inner and outer peripheral end faces, that is, a concave spacer also serves as insulating paper, and the concave spacer is used. In the case where the coil is housed in the concave portion, (5) it is possible to reduce variations in performance and stabilize electrical performance.

(6) The dimension and position accuracy of the end face fusion-bonded portion are improved. (7) When forming the hole for inserting the middle leg magnetic leg, the degree of freedom in the process knitting is improved.

(8) The size setting of the end face fusion-bonded portion can be made small, and the size can be reduced. Further, in the structure in which the concave spacers are used as the upper and lower insulating layers for accommodating the winding, (9) it becomes easy to stack the thin flat coils.

(10) The number of parts can be reduced. Further, in the case where the concave spacer is formed of the molding resin, (11) the dimension and the position accuracy are further improved.

(12) The cost of the spacer can be reduced. In addition, the upper and lower insulating layers are formed of a plurality of layers,
In the structure in which the fusion width of the end face fusion portion is equal to or larger than a predetermined dimension, (13) except for the creeping portion of the lead wire, the thickness regulation in the safety standard can be applied, and in terms of downsizing. It is possible to provide an innovative safety standard conforming structure having a great effect.

(14) Considering the creepage distance from the magnetic core,
When the transformer is mounted on a power source, the secondary component can be close to the magnetic core, and high-density mounting can be easily achieved.

Further, in the case where the upper and lower insulating layers are formed by a plurality of layers, and the periphery of the end face fusion-bonded portion is provided with a predetermined dimension of a resin having a strong adhesive property and mold-sealed, (15) the end face The area around the part has a double insulation structure (basic + auxiliary insulation), making it possible to comply with safety standards.

(16) Since the dimensional control and the like in the manufacturing process of the end face fusion-bonding part are not necessary and the double safety structure can be realized, a higher safety structure can be realized.

Further, in the case where the whole laminated coil is molded, (17) the treatment of the periphery of the end face fusion-bonded portion can be performed once, so that the manufacturing process can be simplified and the productivity can be improved.

Further, in the case where the laminated transformer of the present invention is used in a power supply device, (18) it becomes possible to mount a higher density as a power source, and it is possible to obtain a small size, high safety, which cannot be obtained by a conventional laminated transformer. It is possible to provide an innovative power supply device that meets the demands of the times such as high quality at low cost.

[Brief description of drawings]

FIG. 1 is a cross-sectional view illustrating a laminated structure of a first embodiment which is an embodiment of a laminated transformer of the present invention.

FIG. 2 is a plan view of a flat coil which is the main part of the same.

FIG. 3 is a cross-sectional view illustrating a laminated structure of a laminated transformer showing the second embodiment.

FIG. 4 is a view showing a laminated structure of flat coils showing the third embodiment.

FIG. 5 is a configuration diagram of a thin flat coil showing an essential part of the fourth embodiment.

FIG. 6 is a sectional view of a laminated transformer showing the fifth embodiment.

FIG. 7 is a sectional view of the fifth embodiment as seen from another direction of FIG.

FIG. 8 is a diagram showing another embodiment of the fifth embodiment.

FIG. 9 is a sectional view of another embodiment of the fifth embodiment.

FIG. 10 is an enlarged cross-sectional view of an end face fusion-bonding part which is a main part of the sixth embodiment.

FIG. 11 is an enlarged cross-sectional view of an end face fusion-bonding part which is a main part of another embodiment of the sixth embodiment.

FIG. 12 is a sectional view of a conventional laminated transformer.

FIG. 13 is a sectional view of the other laminated transformer.

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

[Explanation of symbols]

 1 Magnetic Core 2 Winding 2a Primary Winding 2b Secondary Winding 3 Insulating Paper 4 Coil Case 5 End Face Fusion Part 6 Leader Wire 6a Primary Leader Wire 6b Secondary Leader Wire 7 Holes for Inserting Middle Foot Magnetic Legs 8 Recessed Shaped spacer 8a Resin molded spacer 9 Resin

Claims (7)

[Claims] 1. A primary or secondary winding of a thin flat coil in which upper and lower insulating layers are integrated by fusion or the like at other end face portions excluding the end face portion on the side where the lead wire of the winding is pulled out. Of the primary winding and the secondary winding are laminated so that the lead-out directions of the primary winding and the secondary winding are opposite to each other, and a laminated coil is formed, and a closed magnetic circuit is formed from the direction in which the coils are laminated. A laminated transformer that incorporates the magnetic core that constitutes the. 2. A flat coil spacer formed by forming a convex portion having a predetermined width and height on at least a part of the inner and outer peripheral end faces, that is, a concave spacer also serves as insulating paper, and the concave spacer is also used. The laminated transformer according to claim 1, wherein the coil is housed in the recess of the. 3. A laminated transformer according to claim 2, wherein concave spacers are used as upper and lower insulating layers for accommodating the coils. 4. The laminated transformer according to claim 2, wherein the concave spacer is formed of a molding resin. 5. The laminated transformer according to claim 1, wherein the upper and lower insulating layers are formed of a plurality of layers, and the fusion width of the end face fusion portion is not less than a predetermined dimension. 6. The method according to claim 1, wherein the upper and lower insulating layers are formed of a plurality of layers, and the periphery of the end face fusion-bonded portion is molded and sealed with a resin having a strong adhesive property to a predetermined size. Stacked transformer. 7. The laminated coil as a whole is molded.
The described laminated transformer.