JPH07240324A - Small-sized transformer - Google Patents

Abstract

PURPOSE:To provide a small-sized transformer which can be suitably mass-produced and reduced in manufacturing cost by easily forming a barrier in accordance with the kind of the transformer without changing the ferrite core, bobbin, etc., of the transformer. CONSTITUTION:A double-coated adhesive tape 21a is wound around the cylindrical winding section 20a of a bobbin 20 and non-winding parts are formed near the flanges 20b and 20c of the bobbin 20 for forming barrier spaces 22 and 23. Then a primary coil 14P1 is formed of a winding on the outer periphery of the tape 21a and other coils 14S1, 14S2, 14P2, and 14P3 are successively formed of windings with double-coated adhesive tapes 21b, 21c, 21c, and 21d in between so that other non-winding parts can be formed similarly.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a small transformer provided in a power supply circuit of various electric devices.

[0002]

2. Description of the Related Art FIG. 7 is a partially cutaway front view of a small transformer used for a power supply circuit, FIG. 8 is an electric circuit diagram of the same transformer, and FIG. 9 is an enlarged sectional view taken along line AA of FIG. It is a figure. As shown in the figure, this small transformer is composed of two E-shaped ferrite cores 11 and 12 of the same shape, a bobbin 13, primary coils 14P _{1 to} 14P ₃ , and secondary coils 14S ₁ and 14S ₂ .

The bobbin 13, which is an electrically insulating material, is formed by molding a synthetic resin material, and has a rectangular cylindrical winding portion 13a and collars 13b and 13c integrally formed on the upper and lower sides of the winding portion 13a.
It has and. The terminal pins 15 are planted at equal intervals on both sides of the lower flange 13c.
A guide groove 16 at the end of the coil is provided between the planting portions of No. 5.

Further, parallel protrusions 13d and 13e are provided on the outer surfaces of the upper and lower collars 13b and 13c so as to protrude to the outside of the yoke portions of the ferrite cores 11 and 12, and the collars 1b and 13e are formed.
Barriers 13f and 13g are provided on the inner surfaces of 3b and 13c.

The barrier 13f has a length L ₁ from the inner surface of the collar 13b, and the barrier 13g has a length L ₂ from the inner surface of the collar 13c and is integrally formed along the circumference of the winding portion 13a. That is, in the small transformer of this conventional example, the barriers 13f and 13g are integrally formed on the outer circumference of the winding portion 13a along the cylinder axis direction of the winding portion 13a, and the height thereof is H.
Has become a barrier.

A primary coil 14P ₁ is wound between the barriers 13f and 13g, and an insulating tape 17a is wound around the outer circumference of the coil 14P ₁ . Further, the secondary coil 14S ₁ is wound outside the insulating tape 17a, the insulating tape 17b is wound around the outer periphery of the coil 14S ₁ , and the secondary coil 14S ₂ is wound outside the insulating tape 17b. Has been done.

Furthermore, the secondary coil 14S ₂ of the outer peripheral insulating tape - flop 17c is wound around the primary coil 1 to the outside
4P ₂ is wound, an insulating tape 17d is wound around the outer circumference of the coil 14P ₂ , and the primary coil 14P ₃ is wound outside the tape 17d. And
This primary coil 14P ₃ has an outermost insulating tape 1
7e is wound. Also, the above-mentioned insulating tape 1
7a to 17e are single-sided adhesive tapes, and are insulated tapes.
The outer surface of the tapes 17a to 17d is an adhesive surface and an insulating tape.
The wrap 17e is wound such that the inner surface side becomes an adhesive surface.

Incidentally, the above-mentioned coils 14S ₁ and 14
S ₂ , 14P ₂ and 14P ₃ are wound apart from the inner surfaces of the bobbin collars 13b and 13c by a predetermined distance to form a barrier space between the coils. The winding start end and winding end of each of these coils are fixed to each terminal pin 15 through the guide groove 16 of the collar 13c.

Further, the ferrite cores 11 and 12 are assembled by inserting the central legs of the bobbin 13 from above and below into the winding portion 13a, and the leg end faces are adhered by an adhesive.

On the other hand, FIG. 10 shows a conventional example in which barriers 18 and 19 are formed by winding an insulating tape. That is,
Barrier is not formed integrally with the bobbin 20 in this conventional example, a flange 20b, 20c inner surface near the winding section 20a located in the elongated insulating tape - width L ₁ by winding up, L _2, the height H Barrier 18 and 19 are formed. Others have the same configuration as the above-mentioned conventional example.

[0011]

In the small transformer as described above, it is necessary to set the distance between the primary coil and the secondary coil, that is, the creepage distance. Particularly, in this small transformer, the high voltage side is set. Primary coil 14P ₁
When the secondary coil 14S _1, barrier 13f to set the creepage distance between the 14S _2, and 13g are provided, also needed in the safety standards for the predetermined length or more creepage distance.

However, the barrier 13 as described above
Since f and 13g are formed integrally with the bobbin by forming the bobbin 13, the ferrite cores 11 and 12 and the bobbin 13 are newly designed each time the type (or type) of the transformer is changed, or the production types thereof are changed. Must be created. This is a barrier 13f, depending on the transformer model.
This is because the lengths L ₁ and L ₂ and the height H of 13 g change. As a result, there is a problem that the production cost of the transformer also increases.

Further, the barrier 18 is formed by winding an insulating tape.
When forming 19, the ferrite core and bobbin common to the transformer models can be used, but there is a problem that the barriers 18 and 19 must be formed in advance prior to the winding. That is, since an insulating tape having the same width as the barrier widths L ₁ and L ₂ is wound around each transformer in accordance with the height H, this barrier formation becomes an extremely inefficient work, and mass production of transformers is performed. Not good for

In view of the above situation, the present invention can easily form a barrier corresponding to the transformer model without changing the ferrite core, the bobbin, etc., and thereby a small transformer suitable for mass production and cost reduction of production. The purpose is to provide.

[0015]

In order to achieve the above-mentioned object, in the present invention, as a first invention, a bobbin having a collar on both sides of a tubular winding portion is provided, and at least two or more coils are provided. In a small transformer having a winding formed on a tubular winding part, after winding a double-sided adhesive tape, the coils are formed on the outer surface side of this adhesive tape in order. In addition to forming a winding, each of these coils is formed so as to be separated from each of the collars on both sides of the bobbin by a predetermined distance, and a barrier space is formed between the coils that require a predetermined creepage distance. We propose a small transformer that does.

According to a second aspect of the present invention, in the above small transformer, a mold resin is filled between coil windings, and a barrier made of the mold resin is formed in a non-winding portion between the coil and the collar. We propose a compact transformer.

[0017]

In the compact transformer of the present invention, the double-sided adhesive tape is wound around the cylindrical winding portion of the bobbin prior to winding the coil. Then, the coil to be wound first is wound on the outer surface side of the double-sided adhesive tape. In the case of winding in this way, a barrier space is provided without winding a predetermined distance from each of the collars of the bobbin.

A double-sided adhesive tape is wound around the outer circumference of the coil wound first as described above. Then, the next coil is wound on the outer surface side of this adhesive tape, but even if it hits the winding of this coil, a non-winding portion is provided without winding a predetermined distance from the bobbin collar.

In this way, each coil is formed on the outer surface side of the double-sided adhesive tape, and the required number of coils are sequentially wound. Since it is located between the coils, the winding of each coil is fixed by the adhesion of the adhesive tape, and the barrier space is reliably formed without winding collapse or positional deviation of the winding.

Further, after forming the winding of each coil, by filling the molding resin between the windings, the above-mentioned barrier space is filled with the molding resin, and a barrier is formed by this molding resin. To be done.

[0021]

Embodiments of the present invention will now be described with reference to the drawings. FIG. 1 is a sectional view of a transformer showing an example in which the present invention is applied to a small transformer similar to the conventional example. In this drawing, the same parts and parts as those in the conventional transformer are designated by the same reference numerals and the description thereof will be omitted.

As shown in the figure, this small transformer has a tubular winding portion 20 of the bobbin 20 prior to winding the coil.
A double-sided adhesive tape 21a is wound around a. This adhesive tape
As shown in FIG. 2, the cap 21a is provided with both collars 20 of the bobbin 20.
The tubular winding portion 2 has a tape width corresponding to between b and 20c.
0a is wound around the cylinder axis and fixed to the outer peripheral surface of the cylindrical winding portion 20a.

After winding the adhesive tape 21a, as shown in FIG. 3, the primary coil 14P ₁ is wound on the outer surface side of the adhesive tape 21a. The primary coil 14P ₁ is wound such that a distance of X ₁ from the inner surface of the collar 20b and a distance of X ₂ from the inner surface of the collar 20c are set, and the coil cross-section layer has a trapezoidal cross section as shown by a two-dot chain line in the figure. Line.

By winding in this way, the coil of the first layer is fixed to the adhesive tape 21a, so that the barrier space 22 is formed near the collar 20b and the barrier space 23 is formed near the collar 20c. It The trapezoidal section of the coil cross-section is for preventing winding winding collapse of the coil. Therefore, when the number of turns of the primary coil 14P ₁ is small, it is not always necessary to use such a coil cross-section layer.

After winding the primary coil 14P ₁ , as shown in FIG.
As shown in, a double-sided adhesive tape 21b similar to the above-mentioned adhesive tape 21a is wound around the outer circumference of the primary coil 14P ₁ .
The secondary coil 14S ₁ is formed on the outer surface of the adhesive tape 21b.

The secondary coil 14S ₁ is wound so that the trapezoidal cross-section layer of the primary coil 14P ₁ extends in the height direction, and a predetermined space is provided between the flanges 20b and 20c. The secondary coil 14S ₁ is the primary coil 14P ₁
Since it is adjacent to, it is preferable to wind the double-sided adhesive tape 21b a plurality of times.

Similarly, after the double-sided adhesive tape 21c is wound, the secondary coil 14S ₂ is formed on the outer peripheral surface of the adhesive tape 21c, and then the double-sided adhesive tape 21c is formed. 21
After winding the d, the adhesive tape - a primary coil 14P ₂ on the outer peripheral surface of the flop 21d and winding form further double-sided adhesive tape -
After turning the flop 21e winding, the adhesive tape - a primary coil 14P ₃ on the outer surface side of the flop 21e and the winding formed, finally one-sided adhesive tape - wound around the outer periphery of the primary coil 14P ₃ a flop 21f. Incidentally, the double-sided pressure-sensitive adhesive tape - it is preferable to turn around a plurality of times because flop 21d becomes between the primary coil 14P ₂ and the secondary coil 14S _2.

By winding in this way, the coil cross-section layer of each coil has a trapezoidal cross-section as shown by the chain double-dashed line in FIG. 5, and barrier spaces are formed on both sides of each coil.

However, in reality, the double-sided adhesive tape 21b-
21e and the single-sided adhesive tape 21f adhere to each other,
Secondary coils 14S ₁ and 14S ₂ , primary coils 14P ₂ and 1
Barrier spaces on both sides of 4P ₃ do not occur, and the barrier is formed by an adhesive tape. Further, in the space on both sides of the primary coil 14P ₁ , the double-sided adhesive tapes 21a and 21b are partially adhered or remain as a space, where a barrier space is formed.

In winding as described above, the coil ends of the respective coils are wound while being twisted on the terminal pins 15, and the twisted portions are fixed by soldering or the like later. . Subsequently, the ferrite cores 11 and 12 are assembled to the bobbin 20 in the same manner as in the conventional example, whereby the small transformer shown in FIG. 1 is constructed.

FIG. 6 shows an embodiment in which a mold resin is filled between the coil windings of the small transformer constructed as described above. As the mold resin, urethane rubber, silicone rubber, etc. can be used. In this example,
Since the barrier space is filled with the mold resin, the barriers 24 and 25 of the mold resin are formed, and the compact transformer with higher safety is obtained.

Although the embodiments of the present invention have been described above, the number of coils of the primary coil and the secondary coil, the winding layer position of these coils, etc. can be arbitrarily changed.
Further, the primary coil 1 is provided on the outer peripheral surface of the double-sided adhesive tape 21a.
In addition to 4P ₁ , in the case of a low voltage coil, two coils can be formed. Further, the shapes of the ferrite core and the bobbin can be changed as required. When the present invention is carried out, the adhesive tape 21a
It is convenient to use tapes 21f having a tape width slightly wider than the width between the bobbin collars 20b and 20c.

The present invention is not limited to the plug-in type terminal pin 15 as shown in the figure, but can be similarly implemented as a small transformer having a surface solder type terminal pin for surface soldering to the surface of the circuit board. In addition to the vertical transformer as described above, the same can be applied to a horizontal transformer having the core legs in the horizontal direction.

[0034]

As described above, in the small transformer according to the present invention, the double-sided adhesive tape is wound and the coil is formed on the outer peripheral surface of the tape. It is possible to easily construct a barrier space that does not shift the line position and that varies depending on the model of the transformer. If a mold resin is filled between the windings, a barrier of the mold resin can be formed.

As a result, various small transformers with a barrier can be produced by using a ferrite core or bobbin which can be commonly used for various transformers, which is extremely advantageous for mass production and low cost of the transformer.

[Brief description of drawings]

FIG. 1 is a sectional view of a small transformer showing an embodiment of the present invention.

FIG. 2 is a view showing a state in which a double-sided adhesive tape is wound around a bobbin winding portion of the small transformer.

FIG. 3 is a diagram showing a first layer coil winding state of the small transformer.

FIG. 4 is a diagram showing a second layer coil winding state of the small transformer.

FIG. 5 is a diagram showing a winding state of each coil included in the small transformer.

FIG. 6 is a sectional view of a small transformer showing an example in which a barrier is formed by filling a mold resin.

FIG. 7 is a partially cutaway front view of a small transformer shown as a conventional example.

FIG. 8 is an electric circuit diagram of the above-mentioned conventional transformer.

FIG. 9 is an enlarged cross-sectional view of the above-mentioned conventional transformer.

FIG. 10 is an enlarged sectional view of a conventional transformer in which a barrier is formed by winding an insulating tape.

[Explanation of symbols]

11,12 ferrite core 14P _1, 14P _2, 14P ₃ primary coil 14S _1, 14S ₂ secondary coil 15 terminal pin 20 bobbins 20a winding portion 20b, 20c flange 21a~21e sided adhesive tape - flop 21f single-sided adhesive tape - flop 22,23 Barrier space 24,25 Barrier

Claims (2)

[Claims] 1. A small-sized transformer having bobbin having a collar on both sides of a tubular winding portion, wherein at least two or more coils are formed on the tubular winding portion, and a double-sided adhesive tape is provided. After winding, the coils are sequentially formed by winding the coils on the outer surface side of the adhesive tape, and the coils are separated by a predetermined distance from each side collar of the bobbin. A small transformer characterized in that a winding is formed and a barrier space is formed between coils that require a predetermined creepage distance. 2. A mold resin is filled between the coil windings,
The small transformer according to claim 1, wherein a barrier made of a mold resin is formed on a non-winding portion between the coil and the collar.