JPH10229019A - Transformer assembling method, transformer, and transformer mounting substrate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To constitute a transformer such that the rapture strength of the transformer may be increased, the performance of a ferrite core may be brought out sufficiently, and the size and weight of the transformer may be reduced. SOLUTION: In order to constitute a transformer 10 of a bobbin 2, on which a winding section 2f having a through-hole section 2t for winding primary- and secondary-side windings 3 and primary- and secondary-side winding fixing sections, which are continuously formed from openings on both sides of the through hole section 2t are integrally formed and a magnetic core 1 is provided. Thus the core 1 surrounds the windings 3, and a base material 4 used for forming a shock-absorbing section is arranged in the space section S, formed between the primary- and secondary-side winding fixing sections and the magnetic core 1 and impregnating the base material 4 with an impregnating agent, containing 9 varnish 8.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a transformer assembling method, a transformer, and a circuit board mounted with a transformer, and more particularly to a technique which can be particularly suitably applied to a transformer for a switching power supply using a ferrite core used in a power supply. Things.

[0002]

2. Description of the Related Art In general, a switching type power supply has advantages in that it can be made smaller and lighter than a dropper type power supply and has higher conversion efficiency. It is widely used for built-in power supplies and AC adapters.
As a result of the widespread use of the switching-type power supply device, various small and lightweight electronic devices can be easily carried by women and children, and their industrial contribution is highly evaluated.

Referring to the drawings, a transformer mounted on the substrate of such a switching type power supply device will be briefly described. FIG. 7 is a fragmentary sectional view of a conventional transformer 100 generally used. The varnish 108 covers the entire outer peripheral surface of the main body composed of the bobbin 102 wound with the coil 103 and the core 101 to obtain a finished product.

In the above configuration, each transformer 100 is configured to be comparatively flat, so that it can contribute to reduction in size and weight after being mounted on a board. However, such a reduction in size and weight has led to a new problem that when incorporated in a device, the device is exposed to an excessive impact load due to improper handling during transportation or the like.
Also, in the case of a power supply built into an AC adapter used on a desk, the power cord is hooked during use and the like, so that it can withstand an excessive impact load, assuming that it falls from the desk. There was a problem that required new countermeasures.

[0005] When the impact load acts as described above, the power supply device side includes various electronic components constituting the power supply device.
It has been found that excessive impact loads concentrate on relatively heavy transformers.

As shown in FIG. 8, the transformer is seriously damaged when an external force in the direction of arrow F acts on the mounting board K. That is, when an external force is applied, a moment in the direction of arrow M acts on the transformer 100. Then, the transformer 1
After being inserted into the mounting hole Ka of the substrate K by the lead pin P of 00, a sharp pulling force acts on the thin portion 102a on one side of the bobbin 102 fixed by the solder H in the pattern portion, resulting in the thin portion It is known that a breakage phenomenon of a transformer, which breaks from the wire 102a and breaks the lead wire 103, occurs.

Therefore, as a measure for preventing such breakage,
In order to improve the breaking strength of the bobbin 102, a thin portion 102a integrally formed from both sides of the bobbin wound portion of the coil 103
In this case, a reinforcement measure for providing a large C chamfer as shown in FIG. 7 is taken. Alternatively, JP-A-6-96
As disclosed in Japanese Unexamined Patent Publication No. 965-965 and Japanese Unexamined Patent Publication No. Hei 6-163278, there has been proposed a fixing method in which a transformer main body is housed in an outer case that holds the entire transformer and a gap is filled with a resin.

[0008]

However, as described above, the C-chamfered portion is provided in the thin portion 102a of the bobbin 102. According to the method of increasing the fracture resistance, the outer dimensions of the ferrite core used vary widely, so that a gap is formed between the ferrite core and the endurance of the ferrite core. There is a problem that it becomes difficult.

If the bobbin 102 is made to have a sufficient thickness and a sufficient C-chamfered portion is formed in order to obtain a bobbin 102 having a sufficient strength, the effective window area as a transformer can be set large. Will disappear.
For this reason, there is a problem that the performance of the ferrite core incorporated in the bopin opening cannot be sufficiently brought out.

On the other hand, as disclosed in JP-A-7-300561, a method of using a resin having high mechanical strength for the bobbin material itself has been proposed. However, the usable materials for transformer bobbins must meet all safety standards of each country, such as UL standards, so that materials that meet all of them will be considerably more expensive than conventional materials. There's a problem. In addition, from the viewpoint of actual use in the market, there is a problem that using a new material involves a great risk.

Further, as disclosed in the above-mentioned JP-A-6-96965 and JP-A-6-163278, a method of accommodating a transformer main body inside an outer case holding an entire transformer and fixing the same by resin filling is disclosed. According to this, not only is the cost increased, but also the transformer becomes large and heavy, and the advantages that the switching power supply device is small and lightweight cannot be fully utilized.

[0012] Accordingly, the present invention has been made in view of the above-mentioned problems, and it is possible to increase the fracture resistance, to sufficiently obtain the performance of a ferrite core, and to configure the ferrite core to be small and lightweight. The purpose of the present invention is to provide a transformer assembling method, a transformer and a circuit board on which the transformer is mounted.

[0013]

In order to solve the above-mentioned problems and to achieve the object, according to the present invention, a primary winding and a secondary winding are provided.
A winding portion having a through-hole portion where the winding of the secondary winding is performed,
A bobbin integrally formed with a primary winding fixing portion and a secondary winding fixing portion continuously formed from both side openings of the through hole, and a bobbin inserted into the through hole and surrounding the winding; In a transformer assembling method for forming a transformer from a magnetic material core provided, a shock absorbing portion is formed in a space formed between the primary winding fixing portion and the secondary winding fixing portion and the magnetic material core. And an impregnating step of impregnating an impregnating material including a varnish.

Further, a winding portion having a through hole through which the primary winding and the secondary winding are wound, and a primary winding continuously formed from openings on both sides of the through hole. In the transformer, comprising: a bobbin integrally formed with a fixing portion and a secondary winding fixing portion; and a magnetic material core inserted into the through-hole portion and provided to surround the winding, A base material for forming a shock absorbing portion is disposed in a space portion formed between the wire fixing portion and the secondary winding fixing portion and the magnetic material core, and an impregnating material including a varnish is impregnated. It is characterized by:

A winding having a through-hole through which the primary winding and the secondary winding are wound, and a primary winding continuously formed from openings on both sides of the through-hole. Transformer mounting in which a transformer including a bobbin integrally formed with a fixing portion and a secondary winding fixing portion and a magnetic material core inserted into the through hole and provided to surround the winding is mounted on a substrate. In the substrate, a base material for forming a shock absorbing portion is arranged in a space formed between the primary winding fixing portion and the secondary winding fixing portion and the magnetic material core, and a varnish is formed. It is characterized by mounting a transformer that has been impregnated with an impregnating material.

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments according to the present invention will be described below with reference to the accompanying drawings.

First, FIG. 1 is a partially cutaway view of a state in which the transformer of the first embodiment is mounted on a circuit board K as viewed from the front. FIG. 2 is an enlarged sectional view of a main part of FIG.

In both figures, a bobbin is formed by injection resin from a predetermined resin material, and has a through-hole 2f having a through-hole 2t in which a primary winding and a secondary winding 3 are formed. A primary winding fixing part and a secondary winding fixing part continuously formed from both side openings of the part 2t are integrally formed. The magnetic material core 1 is divided into two parts. The core part is inserted into the through hole 2 t and provided so as to surround the winding 3 to constitute the transformer 10. The printed circuit board K on which the transformer 10 is mounted is a pedestal 2 of the bobbin 2 of the transformer 10.
k contacts, the lead pin P serving as a terminal of the transformer 10 is inserted into the mounting hole Kb, and then fixed with the solder H.

The outside of the winding 3 wound around the winding portion 2f of the bobbin 2 is covered with an insulating tape 7, and is covered with a varnish 8 impregnated entirely.

On the other hand, between the primary winding fixing part, the secondary winding fixing part, the upper surface of the magnetic material core 1 and the bottom surface of the magnetic material core 1 which are continuously formed from both side openings of the through hole 2t. A silicone rubber 4 having a predetermined thickness is inserted in the gap, and is fixed with a varnish 8.

In order to obtain the transformer 10 having the above-described structure, in the flowchart of the transformer assembling process shown in FIG. 6, first, in step S1, as shown in FIGS. A lead wire is pulled out from the bobbin 2 of 10 and connected to the lead pin P by hanging it.

Thereafter, the magnetic material core 1 is assembled in step S2, and in the arranging step of step S3, the silicone rubber 4 is set in the gap S between the bobbin 2 of the transformer 10 and the magnetic material core 1. Then, the process proceeds to the impregnation step of step S4, in which the entire transformer 10 is impregnated with the varnish 8 and hardened.

As shown in the above configuration, by disposing the silicon rubber 4 having a thickness corresponding to the degree of the gap S between the bobbin 2 and the magnetic material 1, the movement of the magnetic material core 1 with respect to the bobbin 2 due to the fall can be restricted. This makes it possible to prevent the bobbin 2 from breaking due to the movement of the magnetic material core 1 of the transformer due to the fall.

In the above configuration, as shown in the external perspective view of FIG. 3, the effect of the transformer 10 mounted on the circuit board K on the drop is effective in any of the XYZ drop directions. This is effective for falling in the Y direction.

With the above configuration, the movement of the magnetic material core 1 in the Y direction due to the impact of the transformer 10 falling in the Y direction can be restricted, so that the moment applied to the pedestal portion 2k of the bobbin 2 due to the movement of the magnetic material core 1 The load of M can be reduced, and the stress concentration on the ridge line at the boundary between the pedestal 2k of the transformer bobbin 2 and the side surface of the bobbin due to the rotational moment M of the magnetic material core 1 due to a drop impact can be dispersed, so that bobbin cracking can be prevented Become.

The silicon rubber 4 is a soft material, and thus becomes an appropriate shock absorber. When a rotational moment M acts, a tensile load acts on one pedestal 2k and a compressive force acts on the other pedestal 2k. However, since these loads are alleviated by the silicone rubber and unnecessary damage is not given to the winding 3 of the transformer, disconnection of the winding of the transformer 10 can be prevented. (Second Embodiment) FIG. 4 is an enlarged view of a second embodiment in which main parts of FIG. 1 are enlarged. In this figure, the same components as those already described are denoted by the same reference numerals, and the description thereof will be omitted. If only the different components are described, in FIG.
A gap S2 is formed between the upper surface portion 2a of the bobbin 2 and the bottom surface of the magnetic material core 1, and the nonwoven fabric 5 is set in this gap to function as an impregnating material through which the varnish 8 penetrates.

In the process of assembling the transformer 10, the nonwoven fabric 5 is provided in the gap S between the bobbin 2 of the transformer 10 having the winding and the magnetic material core 1. Next, the entire transformer 10 is impregnated with the varnish 8. The varnish 8 penetrates into the nonwoven fabric 5 provided on the upper surface 2a of the pedestal portion 2K of the bobbin 2 of the transformer 10 and the bottom surface of the magnetic material core 3.

The impregnated varnish 8 also fills the gap S 1 on the bottom surface of the magnetic material core 1. After the varnish treatment as described above, the varnish 8 is cured by heating the transformer 10.

As shown in the above configuration, the varnish 8 penetrates and cures over the entire area of the nonwoven fabric 5 provided in the gap between the bobbin 2 of the transformer 1 and the magnetic material core 1, so that the varnish 8 has a sticky magnetic material core. An adhesive layer without voids can be formed on the entire interface between the gap 2 and the bobbin 1 and the fixing of the bobbin 2 of the transformer 10 and the magnetic material core 1 can be strengthened.

Varnish 8 provided in gap between magnetic material core 1
The movement of the magnetic material core 1 with respect to the bobbin 2 due to a drop impact can be restricted by the deformation in the thickness direction of the nonwoven fabric 5 impregnated with. Furthermore, the nonwoven fabric 5 impregnated with the varnish 8 becomes an appropriate shock absorber, and can reduce bobbins, thereby preventing bobbin cracking.

In the above configuration, the effect on the fall of the transformer 10 mounted on the circuit board K is effective irrespective of the drop direction, but is particularly effective on the drop in the Y direction shown in FIG. With the above configuration, the movement of the magnetic material core 1 in the Y direction due to the impact of the transformer 10 falling in the Y direction can be restricted.
Of the bobbin 2 can be reduced.

Conventionally, in a drop test corresponding to six surfaces of the case in a state where the transformer 10 is soldered and mounted on the circuit board K and mounted on the case, the height of the work desk (height of about 75 cm) is obtained. Although the bobbin cracked within three repetitions of the dropping, the non-woven fabric 5 having a thickness slightly smaller than the gap S between the bobbin 2 and the magnetic material core 1 was used in the configuration of the present embodiment, so that the dropping was repeated. No bobbin cracking occurred seven times.

As can be seen from the results of the drop test described above, the above-described configuration has made it possible to clearly improve the drop resistance of the transformer 10.

Further, even in a drop test from a height of 1 m, which is more severe than the conventional test, no bobbin crack was generated. On the other hand, the effects other than the effect on the drop impact by impregnating the nonwoven fabric 5 with the varnish 8 include the following.

1) The nonwoven fabric 5 provided in the gap S between the bobbin 2 of the transformer 10 and the magnetic material core 1 is less expensive than silicon rubber.

2) The proper adhesion of the varnish 8 has an effect that the magnetic material core 1 and the bobbin 2 can be fixed to such an extent that the magnetic material core does not crack due to thermal expansion.

3) The varnish impregnation of the main body of the transformer 10 allows the varnish impregnation of the nonwoven fabric 5 to be performed.
Since the fixing of the bobbin 2 and the magnetic core 1 can be strengthened, no special means such as an adhesive is required. (Third Embodiment) FIG. 5 is a partially enlarged view of a side surface of a transformer according to a third embodiment.

In the figure, the same components as those already described are denoted by the same reference numerals, and the description thereof will be omitted. If different components are described, the gap S between the bobbin 2 and the magnetic material core 1 is formed by a woven cloth made of an insulating material. 6 is provided so that the permeability of the impregnating material of the varnish 8 into the insulating member can be controlled by changing the size of the mesh of the woven fabric.

As a result, the most suitable woven fabric can be selected for the permeability of the impregnating material, so that there is an advantage that the adhesive strength is more stable.

Although the measures against the drop of the transformer 10 in each of the above embodiments have been described only for the transformer in which the magnetic material core 1 is placed horizontally, the above-described measures can be applied to the transformer in which the magnetic material core 1 is placed vertically. The configuration is applicable.

As described above, by arranging the insulating member having a thickness corresponding to the degree of the space in the space formed between the bobbin and the magnetic material core, the magnetic properties of the bobbin due to the drop are reduced. It is possible to restrict the movement of the material core and prevent a bobbin crack due to the movement of the magnetic material core of the transformer due to a drop impact or the like.

That is, by providing a suitable shock absorber, it is possible to alleviate the drop impact and prevent unnecessary damage to the winding of the transformer, thereby preventing disconnection of the winding of the transformer. Also, the drop strength of the transformer can be improved by adding simple steps and impregnating with the impregnating material, which is the last step of the conventional transformer assembly, without greatly changing the conventional transformer assembly process. This is convenient because no special means is required.

[0043]

As described above, according to the present invention, there is provided a transformer assembling method which can increase the fracture resistance, can sufficiently bring out the performance of a ferrite core, and can be made compact and lightweight. A transformer and a transformer-mounted circuit board can be provided.

[0044]

[Brief description of the drawings]

FIG. 1 is a front view of a transformer 10 in which a transformer 10 according to a first embodiment of the present invention is mounted on a circuit board and a part of the transformer 10 is broken.

FIG. 2 is an enlarged view of a main part of FIG.

FIG. 3 is an external perspective view illustrating a state where a transformer is mounted on a circuit board.

FIG. 4 is an enlarged sectional view of a main part of a transformer according to a second embodiment.

FIG. 5 is an enlarged sectional view of a main part of a transformer according to a third embodiment.

FIG. 6 is a flowchart of a transformer assembly process.

FIG. 7 is a front view of a transformer mounted on a circuit board of a conventional transformer and partially cut away.

FIG. 8 is a diagram illustrating the operation of a conventional transformer.

[Description of Signs] 1 Magnetic material core 2 Bobbin 3 Winding 4 Silicon rubber 5 Non-woven fabric 6 Woven fabric 7 Insulating tape 8 Varnish

Claims (19)

[Claims] 1. A winding part having a through-hole for winding a primary winding and a secondary winding, and a primary winding continuously formed from openings on both sides of the through-hole. In a transformer assembling method, a transformer includes a bobbin integrally formed with a fixed part and a secondary winding fixed part, and a magnetic material core inserted into the through hole and provided so as to surround the winding. An arranging step of arranging a base material for forming a shock absorbing portion in a space formed between the secondary winding fixing portion and the secondary winding fixing portion and the magnetic material core; A transformer impregnating step of impregnating the material. 2. The transformer assembly method according to claim 1, wherein an elastic body made of an insulating member having a shape substantially occupying the space is used as the base material. 3. An elastic body made of an insulating member having a shape that forms a gap in the space portion after being disposed in the space portion as the base material, and the impregnating material is applied to the gap in the impregnation step. The method of claim 1, wherein the transformer is impregnated. 4. The transformer assembling method according to claim 3, wherein a nonwoven fabric or a woven fabric for actively impregnating the impregnating material by capillary action is disposed in the gap. 5. The transformer assembling method according to claim 2, wherein the elastic body is an industrial elastic material including a silicone elastomer material. 6. The transformer assembly according to claim 1, wherein the base material is a nonwoven fabric or a woven fabric that is disposed in the space and actively impregnates the impregnating material by a capillary phenomenon. Method. 7. A winding part having a through-hole for winding a primary winding and a secondary winding, and a primary winding continuously formed from openings on both sides of the through-hole. A transformer comprising: a bobbin integrally formed with a fixing portion and a secondary winding fixing portion; and a magnetic material core inserted into the through-hole portion and provided to surround the winding. A base material for forming a shock absorbing portion is disposed in a space formed between the wire fixing portion and the secondary winding fixing portion and the magnetic material core, and an impregnation material including a varnish is impregnated. A transformer characterized by that: 8. The transformer according to claim 7, wherein an elastic body made of an insulating member having a shape substantially occupying the space is used as the base material. 9. As the base material, an elastic body made of an insulating member having a shape forming a gap in the space portion after being disposed in the space portion is used, and the impregnating material is applied to the gap in the impregnation step. The transformer according to claim 7, wherein the transformer is impregnated. 10. The transformer according to claim 9, wherein a nonwoven fabric or a woven fabric for positively impregnating the impregnating material by capillary action is disposed in the gap. 11. The elastic body according to claim 8, wherein the elastic body is an industrial elastic material including a silicone elastomer material.
The transformer according to claim 9. 12. The transformer according to claim 7, wherein a nonwoven fabric or a woven fabric disposed in the space portion and actively impregnating the impregnating material by capillary action is used as the base material. 13. A winding part having a through-hole for winding a primary winding and a secondary winding, and a primary winding continuously formed from openings on both sides of the through-hole. Transformer mounting in which a transformer including a bobbin integrally formed with a fixing portion and a secondary winding fixing portion and a magnetic material core inserted into the through hole and provided to surround the winding is mounted on a substrate. In the substrate, a base material for forming a shock absorbing portion is arranged in a space formed between the primary winding fixing portion and the secondary winding fixing portion and the magnetic material core, and a varnish is provided. A transformer mounting board on which a transformer impregnated with an impregnating material is mounted. 14. The transformer mounting board according to claim 13, wherein a transformer using an elastic body made of an insulating member having a shape substantially occupying the space is mounted as the base material. 15. An elastic body made of an insulating member having a shape forming a gap in the space portion after being disposed in the space portion as the base material, wherein the impregnating material is applied to the gap in the impregnation step. 14. The mounting of an impregnated transformer.
The transformer mounting board according to the above. 16. The transformer mounting board according to claim 15, wherein a transformer in which a nonwoven fabric or a woven fabric for actively impregnating the impregnating material by capillary action is arranged in the gap. . 17. The transformer mounting board according to claim 14, wherein a transformer using an industrial elastic material including a silicon elastomer material as the elastic body is mounted. 18. A transformer using a nonwoven fabric or a woven fabric, which is disposed in the space portion and actively impregnates the impregnating material by capillary action, is mounted as the base material. The transformer mounting board according to the above. 19. The transformer-mounted circuit board according to claim 13, wherein the board is a power supply board for incorporating a device.