JPS6048892B2 - Manufacturing method of flyback transformer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method of manufacturing a flyback transformer used in a television receiver.

Flyback transformers used in television receivers generate high voltages of 20 to 25 KV, so it is necessary to provide sufficient insulation between the secondary coil that generates this high voltage and all adjacent components. Normally, the secondary coil of a transformer is housed in a case, and a highly insulating epoxy resin is also placed inside the case. - Tsu -11-L' bar 2,'Y),♂,)4-1''7P?,1's insulation reliability affects the performance of the flyback transformer, and the resin may leak from the case. If the amount is insufficient and the coil etc. is exposed and insulation becomes incomplete, serious accidents such as burning out of the flyback transformer will occur.

Additionally, if resin leaks, the leaked resin will adhere to and harden on the jig used during injection and curing, so not only will it be necessary to remove it, but the life of the jig will be extremely shortened, and even worse. If resin adheres to the anode lead, focus lead, etc. of the flyback transformer, it will render the FBT body unusable, so it is necessary to ensure that the resin never leaks. Figure 1 is a sectional view of the main parts showing an example of the structure of a conventional flyback transformer coil, in which 1 is a primary coil bobbin, 3 is a secondary coil bobbin, 1a is a primary coil,
3a is a secondary coil.

The coil 1a is wound around the cylindrical portion 4 of the primary coil bobbin 1.
and the protruding piece 9 are press-fitted into the recess 5 and the notch 8 of the case 2, and the primary coil bobbin 1J
The cylindrical portion 4 and the protruding piece 9 are designed to be slightly larger than the inner diameters of the recess 5 and cutout 8 of the case 2, so that they fit together without any gaps and are designed to prevent leakage of epoxy resin, etc. It is something that However, the primary coil
The dimensions of the cylindrical part 4 and protruding piece 7 part 9 and the recessed part 5 and notch part 8 of the case 2 change slightly due to variations in molding, and as a result, a gap is created between them, and as a result, the resin 7
It has the disadvantage of leaking. Furthermore, in order to provide the sealing effect by press-fitting, flexible materials must be used for the primary coil bobbin 1 and the case 2, which has the disadvantage that it is difficult to obtain sufficient strength. Figure 2 is a cross-sectional view of the main parts of another example of a conventional flyback transformer, in which the primary coil bobbin 1 and the case 2 are made of a molded material with high hardness. If the cylindrical portion 4 and the protruding piece 9 of the primary coil bobbin 1 are designed to be a little larger, they cannot be press-fitted, so the recessed portion of the case 2 is made to be a little larger or about the same size. Naturally, in this method, a gap is created at the fitting portion of the two and the insulating material leaks, so the joint between the two is bonded and fixed with an adhesive 6 so that there is no gap. This adhesive 6 reduces leakage defects of the resin 7 compared to the press-fitting method shown above, but even in this structure, applying the adhesive 6 is a difficult task that requires considerable skill. Therefore, when mass-produced, there remained the drawback that insulation could leak due to variations in work. That is, in the conventional method of manufacturing a flyback transformer, a primary coil bobbin 1 and a secondary coil bobbin 3 are wound with coils 1a and 3a, respectively.
is the case. After the resin 7 is injected into the case 2 and cured, a step is always required to remove the resin leaked out of the case 2. SUMMARY OF THE INVENTION An object of the present invention is to provide a method for manufacturing a coil for a Franny back transformer that eliminates such conventional drawbacks and prevents resin from leaking out of the case.

In the present invention, the primary coil bobbin and the case are provided with a bottom at the fitting part thereof, and a bottomed bag structure is used, or a bottomed bag structure and a walled structure are used, thereby creating holes and gaps that are the three causes of resin leakage. After the resin is injected and cured and no leakage occurs, the bottom formed in the fitting part is ruptured to completely solve the leakage problem.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be specifically described below with reference to embodiments shown in the drawings.

3A and 3B show a front view and a sectional view of the flyback transformer used in the present invention, in which the fitting parts 24, 25 and 28, 29 of the primary coil bobbin 1 and case 2 are integrally formed. Molded bottom plates 12, 13 and wall plates 14,
15, it has a bag-like structure with a bottom and a walled structure.

In addition, the bottom plates 12, 13 and the wall plates 14, 15 are provided with grooves 1 to facilitate punching through the bottom plate and wall plates after the insulating material is cured. , 11 and 16, 17, respectively. FIG. 4 shows the process of punching out the bottom plates 12, 13 and the wall plates 14, 15 to form the core insertion hole and the core insertion groove after the insulator is hardened.
, 11 and 16, 17, the bottom plates 11, 12 and wall plates 14, 15 can be easily punched out. Figure 5 shows bottom plates 12, 13, wall plates 14,
This figure shows a state in which the cores 18, 18 are inserted into the flyback transformer from which 15 is punched out through the core insertion groove 21 and the core insertion hole 20, and a closed magnetic path is formed.

According to the method described above, the insulator (resin) never leaks, so all problems caused by insulator (resin) leakage can be solved.

In the present invention, as can be seen from the figure, both the primary coil bobbin and the case have a bottomed bag structure and a walled structure, so there is absolutely no possibility that the insulator will leak outside, and the insulator will never leak out due to resin leakage. The problem can be completely solved.

Furthermore, there is the advantage that component materials and labor costs can be reduced compared to conventional structures.

[Brief explanation of the drawing]

1 and 2 are sectional views of a conventional flyback transformer, and FIGS. 3a, 3b, 4, and 5 are sectional views of a flyback transformer used in the present invention. 1...Primary coil bobbin, 2...Case, 12...Primary coil bobbin bottom plate, 13.
...Case, bottom plate, 10...Primary coil bobbin bottom plate kerf, 11...Case bottom plate kerf, 1
4...Primary coil bobbin wall plate, 15...
・Case, wall plate, 16... Primary coil bobbin wall plate kerf, 17... Case wall plate kerf, 18◆. ．．
．． ．．゜Core.

Claims (1)

[Claims] 1. A cylindrical primary coil bobbin on which a primary coil is wound and which has a first bottom plate, and a secondary coil bobbin which is placed outside the primary coil bobbin and has a secondary coil wound thereon and has a second bottom plate. a step of storing the first and second bottoms facing each other in a cylindrical case; a step of injecting and curing an insulating resin between the case and the primary coil bobbin; and a step of injecting and curing the first and second bottoms. A method for manufacturing a flyback transformer, comprising the steps of punching out the bottom of the transformer to form a core insertion hole, and inserting a core into the core insertion hole to form a closed magnetic circuit.