JPS59168608A - Manufacture of fly-back transformer - Google Patents

Abstract

PURPOSE:To obtain prescribed electrical characteristics constant by a method wherein butted ends of U-shape cores are coated with adhesive and gaps between the cores are narrowed by compression and, when inductance reaches a prescribed value, the adhesive is cured completely while the gaps are maintained to that state. CONSTITUTION:A pair of U-shape cores are made of material such as ferrite. Butted ends of one 22 of the cores are coated with a prescribed amount of adhesive 23, 24. One leg of each of the cores 21, 22 is inserted into a bobbin on which a coil is applied and ends of the legs are abutted against each other. Compression jigs 25, 26 are pressed against the bottom surfaces of the cores 21, 22 and moved so as to narrow the gaps between the abutted ends. At that time, the inductance values of the primary coil, the secondary coil and the like are measured and when those values reach within a prescribed range, the movement of the compression jigs is discontinued and, while this state is being maintained, the adhesive is cured completely.

Description

[Detailed description of the invention] The present invention relates to a method for manufacturing a flyback transformer.

FIG. 1 shows the structure of a conventional flyback transformer, in which a high-voltage bobbin 4 having 50 windings of high-voltage coils is inserted into the outside of a low-voltage bobbin 2 having 10 windings of low-voltage coils, and 1 these bobbins. Insulating case 5 with an opening on one side
The cavity inside the case is filled with an insulating material 6 such as epoxy resin, and one leg of each of the pair of U-shaped cores 7.8 is inserted from both sides of the low-pressure bobbin 2 so that their end surfaces are aligned with each other. It is a result of being confronted. In this way, when a pair of U-shaped cores 7.8 are butted together to form a "C" closed magnetic circuit core, insulating spacers 9, 1 are placed on the butted end surfaces.
A predetermined gap is formed between the two cores, and the pair of U-shaped cores are elastically fixed with a U-shaped fixing fitting 11 disposed on the outer peripheral surface. The purpose of forming a gap between the butting end faces of the U-shaped core is to avoid magnetic saturation of the core, but in the mass production process, it is necessary to ensure that this gap remains constant. The magnetic coupling coefficient between coils such as the primary coil and the secondary coil changes, making it impossible to obtain predetermined hypochondriacal characteristics. Therefore, in the conventional flyback transformer, the insulation spacer 9, 1
In addition to strictly controlling the thickness of the core, the abutting end faces of the core must be polished to eliminate minute irregularities, which is a cumbersome process.

The present invention has been made in view of these points, and it is an object of the present invention to provide a method for manufacturing a flyback transformer that can eliminate the above-mentioned conventional troubles.

For this purpose, the present invention applies an adhesive to the abutting end surfaces of the U-shaped core, and during the curing of the adhesive until it is completely cured. Narrow the gap between the cores by applying pressing force from the outer bottom side of the U-shaped core, and completely apply the adhesive while maintaining the gap when the inductance of the coil wound around the core reaches a predetermined value. It is made to harden.

An embodiment of the present invention will be described in detail below with reference to the drawings.

In addition, since the present invention has a special feature in the fixed part of the core, in the drawings below, "["] excludes the coil part for convenience, and only the core part is shown, but in reality, it is shown in Figure 1. There is a coil part similar to that shown in .

In FIG. 2, C121 and C22 are a pair of U-shaped cores made of ferrite material or the like, and a predetermined amount of adhesive 23,24 is applied to the abutting end surfaces of one of the cores 22. The adhesives 23 and 24 are either a one-liquid type or a two-liquid type mixed in advance, and from the viewpoint of workability, it is preferable to use a fast-curing adhesive. This fast-curing adhesive has, for example, a curing time to curing strength ratio as shown in FIG.

Note that since the core material has a large specific gravity, it is essential that the adhesive has sufficient seating strength and that thermal deformation after curing is small. Next, after the adhesive has been applied and a predetermined period of time has elapsed from "C", one leg of each of the cores 21 and 22 is inserted into the bobbin wound with the cores 21 and 22, and their end surfaces are abutted against each other. , as shown in FIG. 4, a pressing jig 25 is brought into contact with their outer bottom surfaces.
, 26 in a direction that narrows the distance therebetween, and applies a pressing force that narrows the gap between the abutting end faces of the core. At this time, at the same time, the inductance value of a predetermined coil such as a primary coil or a secondary coil wound around the bobbin into which the core is inserted is measured. As the gap distance becomes narrower, the inductance value of the coil increases, but when the value falls within a predetermined range determined in advance at the design stage, the movement of the pressing jig is stopped and the gap between the butting end faces of the C core is reduced. prevent it from becoming any narrower.

The flybank transformer is then completed by completely curing the adhesive while maintaining this state. The extent to which the adhesive has hardened after being applied to the core end surfaces before the pair of core end surfaces should be butted together is determined as appropriate in relation to the suppressing force applied from the core outer bottom surface 11111. However, it goes without saying that it will be difficult to accurately adjust the gear spacing if pressure is applied when the adhesive has not cured much, or when it is lying flat without being cured. .

Although the method for manufacturing a flybank transformer of the present invention includes the above-described steps, it is not necessarily limited to the above-mentioned embodiments, and modifications may be made without departing from the spirit of the present invention. It goes without saying that it is possible.

For example, in the above embodiments, the adhesive applied to the core end face is either a -liquid type or a pre-mixed two-liquid type. It is also possible to apply C separately to each end face of the core -i1, and to use such a method that the respective liquids come together and start curing only when the core end faces are brought together. In such cases, curing will not begin unless the pair of cores are butted together, so after applying the adhesive, butt the pair of core end faces together without applying any direct pressure to the core end faces. It is necessary to ensure that the two liquids come into contact with each other. If left in a dry state for a while, the adhesive will harden, so when it reaches a suitable hardening state, you can start applying pressure from the outer bottom side of the C core.Also, configure the flyback transformer. The structure of the coil portions i to 'C is not limited to that shown in Figure 1 b.
It's no good.

Since the method for manufacturing a flyback transformer of the present invention includes the steps described above, there is no need to manage the thickness of the insulating spacer as in the past, and there is no need to polish the end face of the core. The C process has been extremely simplified, and even if there are variations in core magnetic permeability, C can always obtain the specified electrical characteristics, and furthermore, there is no need for insulating spacers, fixing metal fittings, etc., reducing costs. It has various effects that are also advantageous.

[Brief explanation of the drawing]

Fig. 1 is a cross-sectional front view of the main part of a conventional flyback transformer, Fig. 2 is an iE plane view showing only the core part for explaining the present invention, and Fig. 6 shows the ratio of curing time to curing strength of the adhesive. The characteristic diagram shown in FIG. 4 is a front view showing only the core portion for explaining the present invention.
U-shaped core, 23.24...Adhesive. Patent Applicant Murayama Manufacturing Co., Ltd. Figure 1 Figure 2

Claims (1)

[Claims] A pair of U-shaped core legs are inserted into a bobbin on which a coil is wound from both sides, and the end surfaces of these cores are butted against each other to form a closed magnetic circuit core. 9-) A step of applying an adhesive to the end surfaces of the U-shaped cores; b) During the curing of the adhesive, the outer bottom surfaces of a pair of U-shaped cores with their end surfaces abutted against each other are A process in which pressing force is applied from the side, thereby narrowing the gap between the butt end faces. C) Measure the inductance of the coil while narrowing the gap between the butt end faces of a pair of U-shaped cores, and make sure that the inductance reaches a predetermined value. A method for manufacturing a flyback transformer, comprising: completely curing the adhesive while maintaining the gap when the adhesive is removed.