JPS6031094B2 - Transformer manufacturing method - Google Patents

Description

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

Generally, magnetic cores for transformers are made of relatively thin (0.2 to 0.35 willow) magnetic strip steel wound around a wound magnetic core in order to reduce leakage magnetic flux or improve electromagnetic properties. When constructing a transformer using such a wound core, conventionally, after forming the wound core, heat treatment is applied to fix the wound core by vacuum impregnation with thermosetting adhesive, impregnating agent, etc., and the adhesive hardens. Later, the long-side winding portion of the wound core was cut approximately at the center to divide it into two parts, and after surface polishing, etc., the two-parted magnetic core was inserted into the winding frame. Figures 1 and 2 show the case where a transformer is formed by the above-mentioned conventional method, where 1 is a wound core cut approximately at the center of the long side magnetic leg, 2 is a winding frame, and 3 is a winding. , 4 is a rare accessory of the wound magnetic core 1, 5 is a winding lead terminal, and 6 is a mounting bracket.

However, in this case, after the magnetic core 1 is once cut and separated, the cut surfaces are butted against each other, which causes deterioration of the magnetic properties and makes it impossible to obtain desired characteristics.

The present invention aims to provide a method for manufacturing a transformer that eliminates the above-mentioned conventional drawbacks, and makes it possible to improve the electromagnetic properties by making the magnetic material for the wound core thinner and to simplify the core manufacturing process. Low leakage flux is also a way to obtain a good transformer.

An example of this will be described below with reference to FIGS. 3 to 8.

The thinner the magnetic strip steel material is, the more the magnetic loss decreases, and at the same time the high frequency characteristics improve. First, the present invention uses a magnetic steel strip made of a thinner material (0.03 to 0.3 legs) with a low silicon content, or a specific crystalline magnetic material, which has relatively little deterioration of magnetic properties due to internal residual strain of the material during molding. In addition, using a thin magnetic steel material that is relatively easy to roll, it is rolled in a ring shape with an appropriate winding tension (200 k9/me or more), and after winding to a predetermined thickness, the end of the roll is temporarily welded by spot welding, etc. Stop and wind the magnetic core 10
get. After this wound magnetic core 10 is subjected to magnetic recovery heat treatment suitable for each magnetic material, the entire wound magnetic core 10 is molded with a first insulating resin 11. This mold is a wound magnetic core 1
0, in the illustrated example, the resin 11 is molded uniformly over the entire surface of the wound core 10 by holding the concave holding portion 12 provided on each short side magnetic leg of the wound magnetic core 10. The magnetic material is fixed so that abnormal noise is not generated when the magnetic core 10 is excited. At this time, protrusions 13 for positioning the second insulating resin, which will be described later, are provided at both ends of the long side magnetic legs of the first insulating resin''. In this state, next, a second insulating resin 14 different from the first insulating resin 11 is molded around the long side magnetic leg portions of the wound magnetic core 10 molded with the second insulating resin 11. At this time, the second insulating resin 1
4 is located between the protrusions 13 and has collars 15 integrally formed at both ends to form a winding frame portion 16. Here, since the inner surface of the winding frame portion 16 and the surface of the first insulating resin 11 are double-molded with different resins, it is necessary to select the molding temperature, the shrinkage rate of the resin, etc., and the molding method. Therefore, if both are configured in the same circular shape, only the winding frame portion 16 can be made rotatable with respect to the first insulating resin 11. A gear for rotational driving is formed on the outer peripheral edge of the flange portion 15. This state is shown in FIG. On the other hand, FIG. 6 shows a single magnetic leg type in which the winding frame portion 16 is attached only to one long side magnetic leg portion of the wound magnetic core 10. As shown in Fig. 5, in the case of a transformer in which the winding frame portions 16 are attached to both long sides of the wound magnetic core 10, an inner iron type transformer is constructed, and the windings are made to have the same content on both long side magnetic leg portions. In this case, the generated magnetic fluxes cancel each other out, making it possible to easily manufacture a magnetic core for a transformer with extremely low leakage magnetic flux.

The first and second insulating resins 11 and 14 may be selected depending on the molding shrinkage rate, molding temperature, combination of mold release agent, etc.
As the second insulating resin 11, polypropylene, polyacetal, polycarbonate, noryl, ABS, epoxy, polyester, polyethylene terephthalate resin, etc. can be used, while as the second insulating resin 14, relatively low-temperature resin such as polypropylene, polyacetal, polyamide, etc. can be used. Resin materials that can be molded at high temperatures are suitable.

Other embodiments are shown in FIGS. 7 and 8. FIG. 7 shows a single leg type, and FIG. 8 shows a double magnetic leg type. In both cases, when the wound magnetic core 10 is molded with the first insulating resin 11, the pedestal 17 for mounting when the device is assembled is shown. , 18 are also molded at the same time. In addition, in FIGS. 7 and 8, reference numerals 19 and 20 indicate mounting holes provided in the seats I7 and 18, respectively. As explained above, the present invention involves molding a fully wound annular magnetic core almost uniformly with a first insulating resin, and then applying a material different from the first insulating resin to the long side magnetic legs of the later wound core. A winding frame made of a second insulating resin is molded so that the inner diameter is the same as the outer circumference of the first insulating resin, and a toothed collar for rotating the winding frame is provided at both ends of the winding frame. With this method of manufacturing a transformer, it is possible to fix the wound magnetic core and perform surface insulation treatment at the same time.

In addition, it is possible to easily process magnetic cores made of thin magnetic materials and ultra-hard materials such as amorphous magnetic materials, as well as cores with poor material, some dirt during slitter processing, or uneven thickness. Since there is no processing, there is no magnetic deterioration due to processing, and it can be easily used in conjunction with a post-adhesive layer for cushioning material to prevent magnetic deterioration due to mechanical distortion of the material. It is possible to fix by heat fixation, and it is also possible to mold the pedestal for mounting at the same time when incorporating the device, making it possible to streamline the overall manufacturing process.

Furthermore, in terms of electrical insulation, it is possible not only to insulate the windings by the winding frame but also to insulate the core at the same time, making it possible to manufacture products that are even better from a safety standpoint with great ease.

[Brief explanation of the drawing]

FIG. 1 is a perspective view of a magnetic core in a conventional transformer, FIG. 2 is a perspective view of the same transformer, and FIG. 3 is a transformer manufacturing method according to an embodiment of the present invention, in which the molding process with the first insulating resin is completed. FIG. 4 is a cross-sectional view taken along the line A-A in FIG. 3, and FIGS.
Cross-sectional views, Figures 6a and b are perspective views and cross-sectional views of single-leg type transformers, Figures 7a, b, and c, and Figures 8a, b, and c.
FIG. 6 is a front view, a side view, and a plan view showing other embodiments. 10... Winding core, 1 1... First insulating resin, 14... Second insulating resin, 15... Flam part, 16... Winding frame Department. Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Figure 7 Figure 8

Claims (1)

[Scope of Claims] 1. A first step of molding an annular magnetic core formed by overlapping band-shaped steel material with a first insulating resin, and a long side magnetic leg portion of the annular magnetic core that has undergone the first molding treatment. A second insulating resin that can be molded at a lower temperature than the first insulating resin and is different from the first insulating resin is molded to integrally mold a winding frame portion that is rotatable with respect to the annular magnetic core. and a third step of forming tooth-shaped portions on the winding frame portion and the collar portion. 2. The method of manufacturing a transformer according to claim 1, wherein the mounting base is made of the first insulating resin at the same time as the first molding process.