JPH05243057A - Transformer, coil, and coil semi-finished product - Google Patents

Abstract

PURPOSE:To ensure a miniature thin transformer with satisfactory transformation efficiency by bending an insulating substrate for each spiral conductor unit, and laminating first and second windings so as to hold them between the second and first wirings for construction of a coil structure, and further providing external connection terminals on the first and second spiral conductors. CONSTITUTION:On one surface 10a of a flexible insulating substrate of a planar coil 11 two spiral conductors 12a and 13a are formed such that external peripheral ends 12a0 and 13a0 thereof are oppositely directed to each other. On the other surface 10c two spiral conductors 12c and 13c are formed into an S shape as a whole such that one ends thereof 12ci and 13ci are interconnected at locations opposing to the spiral conductors 12a and 13a with the remaining ends 12c0 and 13c0 being opened. An interlayer insulating thin band is held between a folded line 14a of the planar coil 11 and a folded line 14c of the same, said folded line 14a being yielded by folding the coil along a root thereof and the folded line 14 yielded by folding the same along a kink thereof. Further, innermost peripheral ends 12ai and 13ai of the spiral conductors 12a and 13a are interconnected. Thus, a coupling between two electric circuits is improved together with reduction of leakage magnetic flux.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention mainly relates to a small transformer used for a power supply device such as a switching regulator,
The coil body and the coil body semi-finished product.

[0002]

2. Description of the Related Art Conventionally, as a structure of a transformer using a coil body in which a spiral conductor is formed on the surface of a flexible insulating substrate, for example, there is one described in JP-A-63-20805. .. In this known example, a first spiral conductor forming a first winding is formed on both surfaces of a flexible insulating substrate so as to be electrically connected in series along the longitudinal direction thereof, and then the first spiral conductor is formed. A second spiral conductor forming two windings is formed, the insulating substrate is folded and overlapped, and the insulating member is sandwiched between the opposing surfaces of the insulating substrate to form a coil body. ..

[0003]

The above-mentioned prior art is the first
Since the second winding and the second winding are laminated in the axial direction of the core, the leakage flux between the first and second windings becomes large, and the vortices generated in the winding and the surrounding structures are generated. There are problems that the current loss becomes large and the operation of the circuit incorporating this transformer is adversely affected.

In a transformer, the current of the low-voltage winding is usually large, but in a flat coil having a folded and superposed structure, the practical thickness of the conductor is limited to some extent, and a plurality of circuits are used in parallel. Although there are many cases where it is necessary to deal with this, the current situation is that no consideration is given to this point.

An object of the present invention is to reduce the leakage inductance of a thin winding for a transformer and to obtain a transformer having a good transformer efficiency, and further to provide a coil body and a coil body semi-finished product which compose this transformer. With the goal.

[0006]

In order to achieve the above object, a transformer of the present invention is a transformer in which a coil body having a conductor formed on a flexible insulating substrate is mounted on a core, the insulating substrate A plurality of core insertion holes are provided along the longitudinal direction thereof, and the first and second windings are formed on one surface or one surface and the other surface of the insulating substrate.
And second spiral conductors are formed around the core insertion hole, respectively, the first and second spiral conductors are connected in series, and the insulating substrate is bent for each spiral conductor unit. The first or second winding is laminated so as to be sandwiched by the second or first winding to form a coil body, and the core is attached to the core insertion hole of the coil body. Each of the two spiral conductors is provided with an external connection terminal.

Further, in order to provide a coil body which constitutes this transformer, in a transformer in which a coil body in which a conductor is formed on a flexible insulating substrate is attached to a core, the insulating substrate is provided in the longitudinal direction thereof. A plurality of core insertion holes are provided along the first and second windings, and the first and second windings are formed on one surface or one surface and the other surface of the insulating substrate.
Spiral conductors are formed around the core insertion hole, first and second spiral conductors are connected in series, and the insulating substrate is bent for each spiral conductor unit to form a first or a second spiral conductor. Two windings are laminated so as to be sandwiched by the second or first winding.

Further, in order to provide a semi-finished product of a coil body which constitutes this transformer, in a transformer in which a coil body in which a conductor is formed on a flexible insulating substrate is attached to a core, the insulating substrate is provided with the coil body. A plurality of core insertion holes are provided along the longitudinal direction, and the first or second winding is provided on one surface or one surface and the other surface of the insulating substrate when the insulating substrate is bent and laminated. The first and second windings are configured so that the first winding and the second winding are sandwiched between the first and second windings.
And the first and second spiral conductors are connected by connection conductors on an insulating substrate.

[0009]

According to the transformer of the present invention, the plurality of spiral conductors of the first winding or the second windings, which are the first electric circuits, formed on one surface or one surface and the other surface of the insulating substrate. Since the spiral conductor of the second winding, which is the electric circuit of, is folded and overlapped so as to be sandwiched by the second spiral conductor or the first spiral conductor to form the transformer winding. The coupling between the two electric circuits is improved, the leakage flux can be reduced, the loss due to the leakage flux can be reduced, and the transformer efficiency can be improved.

Further, according to the coil body and the coil body semi-finished product of the present invention, the spiral conductors forming the first and second windings for improving the transformer efficiency described above are formed on the flexible insulating substrate. Therefore, the manufacturing time is shortened and mass productivity is improved.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a plan view of one surface of a flat plate coil 11 in which a thin coil for transformer according to the present invention is developed, FIG. 3 is a plan view of the other surface, and FIG. 2 is a plan view of FIG. 1 and FIG. b-
It is a b'cross section. That is, FIG. 1 shows a view of the flat plate coil 11 whose cross-sectional view is shown in FIG. 2 as seen from the direction a, and FIG. 3 shows a view as seen from the direction c. Further, in FIG. 1, the configuration of the surface shown in FIG. 3 is shown by being overlapped with a broken line. Here, as an example, two spiral conductors 12a and 13a having three turns are provided on one surface 10a of the flexible insulating substrate 10 of the flat plate coil 11.
Are formed with their outer peripheral ends 12ao and 13ao facing in opposite directions. On the other surface 10c, one end 12ci and one end 13ci of each of the two spiral conductors 12c, each having one winding, are placed at positions facing the spiral conductor 12a and at positions where the spiral conductor 13c faces the spiral conductor 13a. Connected, the remaining ends 12co and 13co are open, and the whole is S-shaped (may be inverted S-shaped depending on the circuit configuration)
Is formed. Such a flat coil 1
1 is folded as a fold line 14a and a fold line 14c as a mountain fold, and is folded as shown in FIG. 4, and the interlayer insulating ribbon 15 is sandwiched. By connecting the innermost peripheral end portions 12ai and 13ai of the spiral conductors 12a and 13a, a circuit configuration as shown in FIG. 5, that is, a high-voltage winding with 6 turns between the spiral conductor ends 12ao and 13ao is formed. , 12co and 13co, a thin transformer winding 1 having two windings of a low-voltage winding having two turns.

A polymer film is suitable for the insulating substrate 10 and the interlayer insulating ribbon 15 used here, from the viewpoints of thickness and insulating performance. Particularly, a polyimide film is excellent in heat resistance, and terminals are connected by soldering. It is effective for occasions. Further, as a method of forming the conductors 12a, 13a, 12c, 13c, mechanical cutting and printing of a conductor paste can be considered, but shaving by etching is effective in terms of mass productivity. In addition, the inner peripheral end 12a of the spiral conductor
As a method for connecting i and 12ci, there is a method in which the ends which have been solder-plated in advance are overlapped and a large current is passed to heat-weld them due to contact resistance loss.

As shown in FIG. 5, the windings which can be constructed by the above-described embodiment are composed of conductors 12c and 1 which form one circuit.
3c is a so-called sandwich type in which the conductors 12a and 13a forming another circuit are sandwiched, and the structure has a small leakage inductance. According to this configuration, the number of components is smaller than that in the configuration in which the windings of each circuit are separately manufactured and combined, and the complicated work such as the accurate positioning when the two windings are combined is unnecessary. The advantage is that the leakage inductance and the winding having a small loss due to the leakage inductance can be simply configured. Also, the insulation distance between the conductor of the first winding, which is one electric circuit formed on one surface of the insulating substrate, and the conductor of the second winding, which is another electric circuit formed on the other surface, is folded and overlapped. Since there is no change due to processing such as the above, there is also an effect that the risk of a short circuit accident due to insufficient insulation distance between two circuits is eliminated.

An example of forming a transformer using the thin winding 1 shown in the above example will be described below. In FIG. 6, the high voltage terminals 16a and 16b and the low voltage terminals 17a and 17b are first attached to the thin winding 1 by soldering or the like. Although not shown in the figure, resin molding may be performed for the purpose of improving the insulation performance or the like, if necessary. This winding is a magnetic circuit,
Here, as an example, the transformer 2 as shown in FIG. 7 can be configured by combining with the ferrite cores 18 and 19. According to this configuration example, the high-voltage winding between the high-voltage terminals 16a and 16b is 6 times, and the low-voltage winding between the low-voltage terminals 17a and 17b is 2 times, and the transformer has a winding ratio of 6: 2.

Here, the terminals 16a and 16b are attached to the spiral conductor end portions 12ao and 13ao sandwiched between the valley-shaped insulating substrate 10.
An example of connecting the above is shown below. In the method shown in FIG. 8, the insulating substrate 10 and the spiral conductor end portions 12ao and 13ao are distorted, and the interlayer insulating ribbon 1 sandwiched at the time of folding and stacking.
5, the gaps 19a and 19b are provided between the terminals 16a,
16b is inserted and connected. According to this method, the terminals can be connected to the flat coil without special processing.

In the embodiment shown in FIG. 9, the spiral conductor end portion 13ao is formed.
The surrounding insulating substrate 10 is cut out, and the terminal 16a is connected to the notch. The conductor end portion 12ao and the terminal 16b can be similarly connected. According to this embodiment, the terminals can be connected without increasing the winding thickness. In the embodiment of FIG. 10, the insulating substrate 10 around the corners of the winding 13c, which is the low-voltage winding, is provided.
Is cut off leaving a necessary width for insulation, and the conductor end 13ao of the high-voltage winding is arranged in this portion to connect the terminal 16a. The same applies to the connection between the conductor end 12ao and the high voltage terminal 16b. In this embodiment, since the terminals are connected by utilizing the empty spaces at the corners of the spiral conductor, the terminals can be connected without increasing the size and thickness of the winding.

FIG. 11 is a sectional view of a flat plate coil 21 according to another embodiment of the present invention. One side 10 of the insulating substrate 10
The high-voltage winding spiral conductors 12a and 13a are formed in a, but the plan view seen from the direction a is the same as in FIG. On the other hand, a plan view seen from the direction c is shown in FIG. 12. Two spiral conductors 22c and 23c each having one turn are arranged on one surface 10c of the insulating substrate 10 at opposite ends 22co and 23ci, respectively. The plate coil 21 is formed by connecting 22ci and 23co. When this is bent along the mountain fold line 14c and overlapped, the thin transformer winding 3 as shown in FIG. 13 can be constructed. FIG. 14 shows a circuit of this thin winding 3. The spiral conductors 12a and 13a constitute a high-voltage winding having 6 turns, and the high-winding winding has 1 turns.
Two spiral conductors 22c and 23c are arranged and connected in parallel. As a result, the thin winding 3 for the transformer has a winding ratio of 6: 1.

As described above, according to this embodiment, by bending one flat plate coil, the conductor forming one circuit sandwiches the conductor forming the other circuit, and the transformer having a small leakage inductance is used. The winding can be simply constructed, and in particular, in the present embodiment, the low-voltage winding is constituted by two conductors in parallel, which has an effect of being a large-current winding.

A modification of the spiral conductors 22c and 23c for low-voltage winding with one winding shown in FIG. 12 is shown in FIG.
Shown as 2c 'and 23c'. In this embodiment, the spiral conductor ends 22co 'and 23ci' near the mountain fold line 14,
The plate coil 21 'is configured by separating 22ci' and 23co '. According to this embodiment, since there is no conductor in the vicinity of the mountain fold line 14, there is an effect that bending is easy.
It is particularly effective when constructing a winding having a large current and requiring a large cross-sectional area.

FIG. 16 shows an embodiment in which external terminals are attached to a thin transformer 2'which uses the flat plate coil 21 'shown in FIG. Since the low-voltage winding conductors 22c 'and 23c' are separated in the thin transformer 2 ',
When attaching the external terminal, it is necessary to connect it so that it straddles both conductors. Therefore, two connecting ends 25a and 25b
Using the terminal 24 having the conductor ends 22co 'and 23ci
It is better to connect ′ ′ or 22ci ′ and 23co ′.

An embodiment for forming a winding having a large number of turns will be described below. FIG. 17 shows a plan view of one surface of the flat plate coil 39. The one surface 30a of the insulating substrate 30 has four spiral conductors 31a, 32a, 33a, 34a with three turns. On the other surface 30c of the insulating substrate 30, as shown in FIG. 19, four spiral conductors 31c each having one turn are provided.
32c, 33c and 34c are replaced with spiral conductors 31a to 34a.
It is configured at the position corresponding to. 18 shows a sectional view taken along the line bb 'of the flat plate coil 39. FIG. 17 shows a view in the a direction of FIG. 18, and FIG. 19 shows a view in the c direction. FIG. 17
Regarding the surface 30a shown in (3), the spiral conductors all have the same winding direction, but the position of the end is changed by 180 degrees for each one. Then, 32ao and 33ao whose outermost peripheral ends are adjacent to each other are connected. On the other hand, regarding the plane 30c shown in FIG. 19, the spiral conductors 31c and 3 which are adjacent to each other with the mountain fold line 36U interposed therebetween are provided.
The end portions 31ci and 32ci are connected so as to form an S-shaped series connection with the two 2c as a set, and the mountain fold line 36W
The spiral-shaped conductors 33c and 34c adjacent to each other with a pair of end portions 33c and 34c as a set are connected to each other so that the end portions 33c are connected in series in an inverted S-shape.
i and 34ci are connected. The relationship between the S-shape and the reverse S-shape may be reversed depending on the relationship of the potential required for the winding of the transformer to be manufactured.

The flat coil 39 having this structure is attached to the folding line 35.
U, 35V, 35W valley fold (fold lines 36U, 36V,
(Folded at 36 W) and stacked as shown in FIG. 20. The inter-layer insulating ribbons 37a and 37b are sandwiched between the spiral conductors 31a and 32a at the inner peripheral end portions 31ai and 32ai, and the spiral conductor 33a. And 34a are connected at the inner peripheral end portions 33ai and 34ai, the transformer winding 4 as shown in the circuit configuration in FIG.
Can be configured. The winding 4 has an end portion 31ao of the spiral conductor.
High voltage winding with 12 turns between 31 and 34ao, 31co and 32c
A low-voltage winding having two turns is provided between the positions o and 33co and 34co. Therefore, conductor ends 31co, 34co, 32c
By connecting o and 33co, two low-voltage windings each having two turns are connected in parallel. This winding 4 has a turn ratio of 1
It is a 2: 2 transformer winding. At this time, the spiral conductors 32c and 33c have the same potential, the interlayer insulating ribbon between the conductors can be omitted, and the thickness of the winding can be reduced. Also, between the conductor ends 31co and 34co and 32co
2 and 33co, the winding 4 has a turns ratio of 12: 2: 2. In this case, the spiral conductors 32c and 33c may be insulated from each other if necessary. According to the present embodiment described above, the complicated work of combining a plurality of windings is omitted, and a winding having a large number of turns from a single flat plate coil, a winding having a large current, and further three windings or more. The transformer winding can be configured in such a manner that the conductor that forms one circuit sandwiches the conductor that forms the other circuit and the leakage inductance is small.

A modification of the embodiment shown in FIGS. 17 to 21 will be described with reference to FIGS. 22 and 23. FIG. 22 is a modification of the one surface 30c of the flat coil 39 shown in FIG. 19, and the end portions 31c of the spiral conductors 31c ′ and 32c ′ and 33c ′ and 34c ′ which face each other across the mountain fold lines 36U and 36W.
A flat plate coil 39 'is formed by connecting i'and 32co', 31co 'and 32ci', 33ci 'and 34co', 33co 'and 34ci', respectively. The other surface 30a of the plate coil 39 'is the same as the plate coil 39 shown in FIG. This flat plate coil 39 'is connected to the folding line 35.
The windings 4'having a circuit configuration shown in FIG. 23 can be formed by stacking them in a valley fold at V and mountain folds at the fold lines 36U and 36W, and applying predetermined insulation and connection as in the embodiment of FIG. This winding 4'includes conductors 34c 'and 33 with one turn.
c ′ and 32c ′ and 31c ′ are connected in parallel, respectively, and are for a transformer with a winding ratio of 12: 1: 1.
Furthermore, conductor ends 33co ', 32co' and 33ci '
And 32ci 'are connected, it is possible to configure a large-current transformer winding having a winding ratio of 12: 1 and four low-voltage windings in parallel.

Windings 4, 4'that can be constructed in these embodiments
Is a so-called five-layer sandwich structure in which two layers of high-voltage windings are sandwiched between three layers of low-voltage windings, and it is possible to significantly reduce leakage inductance.

Another embodiment of the present invention will be described with reference to FIGS. FIG. 24 is a plan view of the flat coil 59, and FIG.
5 is a sectional view taken along the line bb 'of FIG. The four spiral conductors 51, 52, 5 are provided only on one surface 50a of the insulating substrate 50.
3, 54 are formed. Of these, spiral conductors 51 and 5
2 has three turns as an example, and the spiral conductors 53 and 54 have one turn as an example. The spiral conductors 53 and 54 have their ends 53i and 54i connected to each other. As shown in FIG. 26, the flat coil 59 having this structure is used as mountain fold lines 56V and 56W.
And the valley fold line 55U are folded and overlapped with each other, the inter-layer insulating ribbon 58 is sandwiched, and the end portions 51i and 52i of the spiral conductor are further stacked.
The winding 6 having the circuit configuration shown in FIG. In this embodiment, the number of turns is 6 between the terminals 51o and 52o, and the number of turns is 2 between the terminals 53o and 54o, and the winding 6 is a transformer winding having a winding ratio of 6: 2.

According to the above-mentioned embodiment, the flat plate coil having the conductor provided on only one surface of the insulating substrate is folded and overlapped to form a coil.
Since the winding for the transformer of the circuit can be configured, the complicated process of accurately aligning and forming the conductor patterns on both surfaces of the insulating substrate is not necessary, and the manufacturing process can be simplified.
Since the conductor that will be the high-voltage circuit is sandwiched between the conductors that will be the low-voltage circuit, a winding with a small leakage inductance can be constructed. Further, since there are two insulating substrates between the primary and secondary windings, the dielectric strength is doubled. Furthermore, since the external connection terminals of the two circuits can be formed at opposite positions by sandwiching the conductor, there is an effect that connection work with the outside becomes easy.

As another modification of the present invention, an embodiment in which a winding having a small number of turns and a large current is formed will be described below.

28 to 32 show an example of constructing a two-circuit winding having two or four turns. Four spiral conductors 71a to 7 having one turn on one surface 70a of the insulating substrate 70.
28 and the spiral conductors 71c to 74c are formed on the other surface 70c as shown in FIG.
Make up 9. 29 is a cross-sectional view of the flat plate coil 79, FIG. 28 is a view from the direction a in FIG. 29, and FIG. 30 is a view from the direction c. Spiral conductors 71a and 71c, 72a and 72c, 73a and 73c, 7 facing each other across the insulating substrate 70
4a and 74c are inner peripheral ends 71ai and 71ci, 72 of each other.
ai and 72ci, 73ai and 73ci, 74ai and 74ci
Are electrically connected through through holes 71h to 74h provided in the insulating substrate 70. Further, the portions 72ao and 73co, 72ao and 73c where the outer circumferential ends of the spiral conductor are adjacent to each other.
o is formed as a connected pattern. When such a flat plate coil 79 is bent along the mountain fold lines 76U, 76V, 76W and the valley fold lines 77U, 77V, 77W, and sandwiched between the interlayer insulating ribbons 78a and 78b, the winding 8 shown in FIG. 31 is obtained. The circuit configuration of the winding 8 is as shown in FIG. A pair of spiral conductors 71a and 71c, 72a and 72c, 73a and 73 that face each other across the insulating substrate 70.
Since each of c, 74a and 74c is a circuit having two turns, the pair of spiral conductors 71a and 71c on both sides and the set of spiral conductors 74a and 74c are connected in series or in parallel and the number of turns is four or two. One circuit, the remaining spiral conductor 7
When the sets of 2a and 72c and 73a and 73c are connected in parallel to form another circuit, the turn ratio is 2: 2 or 4 :.
2 transformer windings. In this winding, a set of spiral conductors 71a, 71c, 74a, 74c forming one circuit forms a spiral conductor 72a, 72c, 73 forming another circuit.
Since a and 73c are sandwiched, the winding has a small leakage inductance. Here, the spiral conductors 72a and 7
Since 3a has the same potential as each other, it is not necessary to take an insulation measure in this portion. When the thickness of one conductor is thick, the outer peripheral ends 72ao and 73ao of the spiral conductor, 72co and 73
It may be difficult to bend at the bending lines 76V and 77V of the connecting portion of co. In this case, the outer peripheral edge 72a
It is preferable that one or both of o and 73ao and 72co and 73co are not connected, and are connected after being folded and overlapped.

An embodiment in which a large-current winding is constructed by using a flat coil having a conductor formed on only one surface of an insulating substrate will be described below. In FIG. 33, a spiral coil 81, 82, 83, 84 having one turn is formed on one surface of the insulating substrate 80 to form a flat coil 89. Of these, the spiral conductors 82 and 83 have their ends 82i and 83i connected to each other. When the flat coil 89 is mountain-folded at folding lines 86U and 86W, and valley-folded at 87V, the interlayer insulating thin strip 88 is sandwiched and folded to obtain the structure shown in FIG.
The winding 9 can be configured as shown in FIG. The circuit configuration of the winding 9 is as shown in FIG. 35, and the conductors having the terminals 82o and 83o and having the two turns are connected to the terminals 81i, 81o and 8
It has a configuration in which two conductors having 4i and 84o and having one winding are sandwiched. The winding 9 having this configuration is for a transformer having a winding ratio of 2: 2 in which the spiral conductors 82 and 83 are used in series and a winding ratio of 1: 2 in parallel. When the conductor has a large thickness, the outer peripheral ends 82o and 83o may be formed in a separated pattern and connected later.

As described above, even if a single-sided flat plate coil that does not require accurate positioning when forming conductors on both surfaces of an insulating substrate is used, a large current winding can be dealt with, and a conductor that forms one circuit is compatible with another circuit. It is possible to form a winding having a small leakage inductance by sandwiching the conductor.

An embodiment for reducing the loss of the flat coil will be described below. In FIG. 36, the spiral conductor 121 of the flat coil 120 has two slits 122 as an example.
a and 122b are provided. This flat plate coil 1 is shown in FIG.
A transformer 125 in which a winding 123 formed by stacking 20 and an EI type cores 124a and 124b with a gap are combined.
A cross-sectional view of a configuration example of FIG. In such a transformer, a minute air gap is generated at the joint portion of the core, the magnetic resistance increases, and the leakage magnetic flux X increases. This leakage magnetic flux X is caused by the flat conductor 12
When crossed with 1, an eddy current is generated to increase the loss, and further, there is a problem of overheating. This problem is particularly important for flat plate coils. Therefore, providing the slits 122a and 122b in the conductor 121 as shown in FIG. 36 has the effect of reducing the eddy current. In particular, since the eddy current easily flows in a transformer having a higher operating frequency, the effect of providing the slit as in the present embodiment is great. Although an example in which a slit is provided is shown here, a method of digging a groove to reduce the thickness of the conductor without cutting out a complete slit, making a number of minute holes, providing a notch at the edge of the conductor, or the like A method of increasing the electric resistance may be adopted. As a method of performing such processing, laser processing is also suitable in addition to shaving by etching.

An embodiment of a method for reducing the floating electrostatic capacitance of a transformer using a flat plate coil will be shown below. FIG. 38 shows a winding 132 in which flat plate coils are folded and an EI type core 133a,
The cross section of the transformer 130 which combined 133b is shown. The winding 132 is composed of 10 layers of flat plate coils 131a to 131j as an example of the combination of the primary winding and the secondary winding. Here, insulating spacers 134a to 135e and 135a to 135d are provided on the core 133 according to the present invention in addition to the valley-folded portions of each plate coil.
It is attached to the part that is separated from a and 133b. Insulating spacers 134a to 134e and 135a are provided between each flat coil.
The necessary insulating layers are provided in addition to the components a to d.

Since the flat coil usually has a larger surface area to cross-sectional area of an electric wire than an electric wire having a round cross section, the distance between the flat coils when they are superposed to form a winding is determined only by the need for insulation. And the stray capacitance of the winding may become excessive and affect the circuit incorporating the transformer. Since this stray capacitance is inversely proportional to the distance between the plate coils, it is sufficient to increase the distance between the plate coils in order to reduce the stray capacitance. h) becomes large. Therefore, in addition to the necessary insulating layer on the insulation, by additionally arranging an insulating spacer only on the outside portion of the core window of the plate coil as in the present embodiment, the floating electrostatic capacitance is increased without increasing the maximum height of the transformer. The effect of reducing the capacity is obtained. If it is necessary to further reduce the floating capacitance, an insulating spacer may be additionally arranged inside the valley-folded layers.

[0035]

As described above, according to the transformer of the present invention, the first winding of the first electric circuit formed on one surface or one surface and the other surface of the insulating substrate becomes the first electric circuit. Since the plurality of spiral conductors or the spiral conductors of the second winding which becomes the second electric circuit are superposed so as to be sandwiched by the second spiral conductors or the first spiral conductors, , The coupling between the two electric circuits is improved, and the leakage flux is reduced. As a result, it is possible to reduce the eddy current loss that occurs in the winding and other structures of the transformer due to the leakage magnetic flux, improve the efficiency of the transformer, and reduce the size and thickness.

Further, according to the coil body and the coil body semi-finished product of the present invention, the spiral conductors forming the first and second windings for improving the transformer efficiency described above are formed on the flexible insulating substrate. Therefore, the manufacturing time is shortened and mass productivity is improved.

[Brief description of drawings]

FIG. 1 is a plan view of one surface of a flat plate coil according to an embodiment of the present invention.

FIG. 2 is a sectional view of a flat plate coil according to an embodiment of the present invention.

FIG. 3 is a plan view of another surface of the flat plate coil according to the embodiment of the present invention.

FIG. 4 is a cross-sectional view of a thin winding formed by bending and stacking flat plate coils according to an embodiment of the present invention.

5 is a circuit diagram of the thin winding of the embodiment of the present invention shown in FIG.

FIG. 6 is a conceptual diagram showing a configuration example of a thin transformer using thin windings according to an embodiment of the present invention.

FIG. 7 is a perspective view of the transformer of the present invention shown in FIG.

FIG. 8 is a side view showing an embodiment for connecting terminals to the thin transformer according to the present invention.

FIG. 9 is a front view showing another embodiment in which terminals are connected to the thin transformer of the present invention.

FIG. 10 is a front view showing still another embodiment for connecting terminals to the thin transformer of the present invention.

FIG. 11 is a cross-sectional view of a flat plate coil of a modified example of the present invention.

12 is a plan view of the flat coil of the present invention shown in FIG. 11. FIG.

13 is a cross-sectional view of a thin winding wire formed by bending and stacking the flat plate coil of the present invention shown in FIG.

FIG. 14 is a circuit diagram of the thin winding wire of the present invention shown in FIG.

FIG. 15 is a plan view of a flat coil according to another modification of the present invention.

FIG. 16 is a conceptual diagram of an example in which terminals are attached to the thin transformer of the example of the present invention.

FIG. 17 is a plan view of one surface of a multi-conductor flat coil according to another embodiment of the present invention.

FIG. 18 is a sectional view of the multi-conductor flat coil of the present invention shown in FIG. 17.

FIG. 19 is a plan view of another surface of the multiconductor flat plate coil of the present invention shown in FIG.

FIG. 20 is a cross-sectional view of a thin winding wire formed by bending and stacking the multi-conductor flat coil of the present invention shown in FIGS. 17 to 20.

21 is a circuit diagram of the thin winding of the present invention shown in FIG.

FIG. 22 is a plan view of a modified example of the multi-conductor flat coil of the present invention.

FIG. 23 is a circuit diagram of a thin winding formed by bending and overlapping the multi-conductor flat coil of the present invention shown in FIG. 22.

FIG. 24 is a plan view of an example of the single-sided multi-conductor flat plate coil of the present invention.

25 is a cross-sectional view of the single-sided multi-conductor flat plate coil of the present invention shown in FIG.

FIG. 26 is a cross-sectional view of a thin winding wire formed by bending and overlapping the single-sided multi-conductor flat plate coils of the present invention shown in FIGS. 24 and 25.

27 is a circuit diagram of the thin winding wire of the present invention shown in FIG. 26. FIG.

FIG. 28 is a plan view of one surface of a multi-conductor parallel plate coil that is an embodiment of the present invention.

29 is a sectional view of the multi-conductor parallel plate coil of the present invention shown in FIG. 28.

30 is a plan view of the other surface of the multi-conductor parallel plate coil of the present invention shown in FIG. 28. FIG.

FIG. 31 is a cross-sectional view of a thin winding wire formed by bending and stacking the multi-conductor parallel plate coil of the present invention shown in FIGS. 28 to 30.

32 is a circuit diagram of the thin winding wire of the present invention shown in FIG. 31. FIG.

FIG. 33 is a plan view of a single-sided multiconductor parallel plate coil of the present invention.

34 is a cross-sectional view of a thin winding wire formed by bending and overlapping the single-sided multiconductor parallel plate coil of the present invention shown in FIG. 33.

FIG. 35 is a circuit diagram of the thin winding wire of the present invention shown in FIG. 34.

FIG. 36 is a plan view showing a configuration example of a flat plate coil with slits which is another embodiment of the present invention.

FIG. 37 is a cross-sectional view of a transformer for explaining the effect of the flat plate coil with slit of the present invention.

FIG. 38 is a cross-sectional view of a transformer for reducing stray capacitance as still another embodiment of the present invention.

[Explanation of symbols]

1, 3, 4, 4 ', 6, 8, 9 ... Winding, 2, 2', 12
5,130 ... Transformer, 10,30,50,70,8
0,100 ... Insulating substrate 11,21,21 ', 39,3
9 ', 59, 79, 89, 120 ... Plate coil, 15,
58, 78a, 78b, 88 ... Interlayer insulating ribbon, 18a,
18b, 133a, 133b ... Core.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Tatsu Saito 4026 Kujimachi, Hitachi City, Ibaraki Prefecture, Hitachi Research Institute Ltd. (72) Masanori Yamaguchi 4026 Kujicho, Hitachi City, Ibaraki Prefecture Hitachi, Ltd. Inside Hitachi Research Laboratory

Claims (10)

[Claims] 1. A transformer having a core, on which a coil body having a conductor formed on a flexible insulating substrate is mounted, wherein a plurality of core insertion holes are provided in the insulating substrate along the longitudinal direction thereof.
The first and second spiral conductors forming the first and second windings are formed around the core insertion hole on one surface of the insulating substrate, and the first and second spirals are formed. Conductors are connected in series, and the insulating substrate is bent for each of the spiral conductor units to form the first or second winding in the second winding.
Alternatively, the first winding and the first winding are laminated so as to be sandwiched to form a coil body, the core is attached to the core insertion hole of the coil body, and external connection terminals are respectively attached to the first and second spiral conductors. A transformer characterized by having. 2. A transformer having a core on which a coil body having a conductor formed on a flexible insulating substrate is mounted, wherein the insulating substrate is provided with a plurality of core insertion holes along the longitudinal direction thereof.
First and second spiral conductors forming the first and second windings are formed around the core insertion hole on one surface and the other surface of the insulating substrate, respectively. The second spiral conductors are connected in series, and the insulating substrate is bent for each of the spiral conductor units to form the first or second spiral conductors.
Of the first and second spiral windings are stacked by sandwiching the windings of the second winding or the first winding so as to form a coil body, and the core is attached to the core insertion hole of the coil body. A transformer characterized in that each conductor is provided with an external connection terminal. 3. A transformer having a core, on which a coil body having a conductor formed on a flexible insulating substrate is mounted, wherein a plurality of core insertion holes are provided in the insulating substrate along the longitudinal direction thereof.
The first and second spiral conductors forming the first and second windings are formed around the core insertion hole on one surface of the insulating substrate, and the first and second spirals are formed. Conductors are connected in series, and the insulating substrate is bent for each of the spiral conductor units to form the first or second winding in the second winding.
Alternatively, a coil body is formed by stacking so as to sandwich the first winding. 4. A transformer in which a coil body having a conductor formed on a flexible insulating substrate is mounted on a core, and a plurality of core insertion holes are provided in the insulating substrate along the longitudinal direction thereof.
First and second spiral conductors forming the first and second windings are formed around the core insertion hole on one surface and the other surface of the insulating substrate, respectively. The second spiral conductors are connected in series, and the insulating substrate is bent for each of the spiral conductor units to form the first or second spiral conductors.
2. A coil body, wherein the winding wire is laminated so as to be sandwiched between the second winding wire and the first winding wire. 5. A transformer having a core, on which a coil body having a conductor formed on a flexible insulating substrate is mounted, wherein a plurality of core insertion holes are provided in the insulating substrate along the longitudinal direction thereof.
The first and second windings are formed on one surface of the insulating substrate such that the first or second winding is sandwiched by the second or first winding when the insulating substrate is folded and laminated. A coil characterized in that first and second spiral-shaped conductors are respectively formed around the core insertion hole, and the first and second spiral-shaped conductors are respectively connected by connection conductors on an insulating substrate. Semi-finished product. 6. A transformer having a core, on which a coil body having a conductor formed on a flexible insulating substrate is mounted, wherein a plurality of core insertion holes are provided in the insulating substrate along the longitudinal direction thereof.
The first and second windings are sandwiched between the first and second windings on the one surface and the other surface of the insulating substrate when the insulating substrate is folded and laminated. The first and second spiral-shaped conductors that form the windings are formed around the core insertion hole, and the first and second spiral-shaped conductors are connected by connecting conductors on the insulating substrate. Characteristic semi-finished coil body. 7. A transformer having a core, on which a coil body having a conductor formed on a flexible insulating substrate is mounted, wherein a plurality of core insertion holes are provided in the insulating substrate along the longitudinal direction thereof.
The first and second spiral conductors forming the first and second windings are formed around the core insertion hole on one surface or one surface and the other surface of the insulating substrate. , First and second spiral conductors are respectively connected in series, and the insulating substrate is bent for each spiral conductor unit to generate a magnetic flux generated by the first or second winding. The coil body is constructed by stacking so as to be canceled by the magnetic flux of, and the core is attached to the core insertion hole of this coil body,
An external connection terminal is provided on each of the first and second spiral conductors. 8. The transformer and coil body according to claim 1, wherein at least one of the first and second windings is formed by connecting spiral conductors in parallel or in a combination of series and parallel. A transformer and coil body characterized by. 9. The transformer, coil body and coil body semi-finished product according to claim 1, wherein a slit is provided in the spiral conductor. 10. The transformer and coil body according to any one of claims 1 to 4, wherein an insulating spacer is disposed on a portion of the coil body outside the window of the core when the insulating substrate is folded and laminated. A transformer and coil body characterized by.