JPH03208317A - Converter transformer - Google Patents

Abstract

PURPOSE:To simply construct a multi-stage gap and hence provide a high reliability, high quality, high performance and miniature converter transformer by providing an H-shaped cross section resin molded structure into which a plate-shaped intermediate magnetic core is assembled, and forming a magnetic gap without fixedly combining a one-side edge of the resin-molded structure with the magnetic core. CONSTITUTION:A magnetic gap 6 is formed by a combination of an intermediate magnetic core 2, an H-shaped cross section resin molded structure 5, and a magnetic core 1. In other words, since the position of an intermediate magnetic core 2 can be fixed, magnetic performance accuracy of a magnetic core 1 can be increased. Further, the resin molded structure 5 including the intermediate magnetic core 2 is assembled thereinto and the magnetic core 1 have a spatial gap, and hence a difference between the linear expansion coefficients can be absorbed without producing a crack in the magnetic core 1. Thus, a multi-stage magnetic gap can be constructed simply and chance a high reliability, high quality, high performance and mainiature converter transformer can be yielded.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a converter transformer used in various electronic devices.

Conventional technology In recent years, converter transformers have shifted from being driven at low frequencies to being driven at higher frequencies in order to meet the needs for lighter, thinner, and smaller transformers. sought after by the world.

A conventional converter transformer will be explained below.

FIG. 5 shows a sectional view of a conventional converter transformer. In Fig. 5, 1 is an EE type magnetic core, 3 is a winding 4
5. 10 is a magnetic gap portion formed by incorporating the intermediate magnetic core 9 into the magnetic leg portion of the magnetic core 1, 5 is a magnetic gap portion of an air gap, and 10 is a gap spacer. 6 and 7 are partial views of a magnetic gap portion of a conventional converter transformer. FIG. 6 shows a gap spacer 10 and an air gap magnetic gap 5, with gap dimensions Gl and G.
2, FIG. 6 shows a gap size G1.2 formed using two gap spacers 10. G2 was formed. Further, FIGS. 4a and 4b are partial views of the magnetic gap portion of the converter transformer, which simply illustrates the relationship between the leakage magnetic flux and the gap size.

To explain the configuration with reference to FIG. 5, the winding 4 is wound around the winding core of the bobbin 3. Incidentally, the number of coils of the winding wire is prepared as an arbitrary number of one winding according to the input/output specifications.

(not shown). Next, the bobbin 3 prepared by winding the winding 4 around one side of the magnetic cores 1 (the lower core in the drawing) of the pair of magnetic cores 1 forming a magnetic path is assembled. Next, the gap spacer 10 and the intermediate magnetic core 9 are fixed together by a method such as gluing while applying a constant pressure, and finally, the remaining magnetic core 1 (the upper magnetic core in the drawing) is assembled and fixed by a method such as gluing. and complete it. The method of configuring the gap portion may be as shown in FIGS. 6 and 7, but since the configuration in FIG. 6 is the same as that in FIG. 5, a description thereof will be omitted. The configuration of Figure 7 is shown in Figure 5.
To explain using the drawings, a magnetic core 1, an intermediate magnetic core 9, and two gap spacers 10 forming a pair of closed magnetic circuits are sequentially assembled into a bobbin 3 prepared by winding the winding 4 shown in FIG. The gap spacer 10, the intermediate magnetic core 9, and the pair of magnetic cores 1 are fixed together by bonding or other methods to complete the structure.

In the converter transformer configured as described above, as shown in FIG. 4, the air gap magnetic gap 5 in the magnetic leg portion is divided into two parts, compared to FIG. It is known that the size becomes 1/2 and the spread of the leakage magnetic flux distribution from the gap portion decreases. In converter transformers used at high frequencies, this leakage magnetic flux interlinks with the windings wound on the lower layer of the bobbin and generates eddy current, causing heat generation due to eddy current loss.
When forming a single magnetic gap as shown in FIG. 4a, high-frequency twisted wires have been used to reduce heat generation in the windings. In addition, by forming two or more gaps as shown in Figure 4, which is presented as a conventional example, the spread of leakage magnetic flux distribution is reduced, the eddy current loss occurring in the winding itself is reduced, and heat generation is suppressed. It becomes possible to achieve miniaturization.

Problems to be Solved by the Invention However, in the conventional configuration shown in FIG. 6, since the gap portion 5 is an air gap, when the converter transformer is assembled and completed, the magnetic core 1 on one side and the After completing the fixation of the magnetic core 9 and the gap spacer 10, the other side of the magnetic core 1 is fixed, resulting in poor workability in the assembly process. Further, when the structure shown in FIG. 7 is adopted, the fixing work in the assembly process can be done in one step, but it is necessary to fix the upper and lower surfaces of the intermediate magnetic core 9 and the gap spacer 10 to the abutting surfaces of the magnetic core 1. As a result, the materials used for the metatarsal magnetic legs of the magnetic core 1 are as follows.
This is a combination of the intermediate magnetic core 9, two gap spacers 1, adhesive material at 14 places, and the outer magnetic leg of the magnetic core 1 is only the magnetic core 1 and adhesive material at one place, so a converter transformer is completed as a pair of magnetic cores 1. At this time, the difference in linear expansion rate between the metatarsal peduncle and the lateral peduncle becomes noticeable. Therefore, during heat shock tests or actual use, reliability deteriorates, such as cracking of the magnetic core. Furthermore, the biggest drawback common to the conventional examples shown in Figs. 6 and 7 is that the gap adjustment 1 is difficult, so the magnetic performance accuracy cannot be increased beyond a certain level.
The problem is that it cannot be uploaded. The reason for this will be explained below.

When setting the gap length of the magnetic core for a high-frequency converter transformer, in combination with a common test coil for each magnetic core size called a test coil, it is necessary to set the gap length of the magnetic core for a high-frequency converter transformer. The inductance is measured as a characteristic value of only the magnetic core, and the gap surface is polished and finished so that it falls within the specified standard value. At this time, in the conventional examples as shown in Figs. 6 and 7,
Since the intermediate magnetic core 9 is not fixed, it moves. As you move left and right in the figure, the magnetic properties change. As a result, the gap value set in the test coil becomes inconsistent, resulting in large variations in performance upon completion of assembly, and in some cases, process defects. Therefore, as long as the intermediate magnetic core in the test coil is movable, even if the gap length is adjusted, there is a problem in that there is a limit to the accuracy of magnetic performance.

The present invention solves the above-mentioned conventional problems, and aims to provide a compact converter transformer that can easily configure multi-stage gaps and has high reliability, high quality, and optical performance at a low cost. .

Means for Solving the Problems In order to solve the above-mentioned problems, the present invention forms a magnetic gap in a magnetic leg incorporating a winding of a closed magnetic circuit magnetic core, and forms a cross section H in which a plate-shaped intermediate magnetic core is installed in this magnetic gap. A shaped or concave resin molded body is incorporated, and at least two or more magnetic gaps are formed by not fixing one end of the resin molded body to the magnetic core.

Effect This configuration allows the position of the intermediate magnetic core to be fixed, so
It becomes possible to improve the magnetic performance accuracy of the magnetic core. Also,
Since the resin molded body incorporating the intermediate magnetic core and the magnetic core are not fixed to each other, that is, there is a space gap, differences in linear expansion coefficient can be absorbed, thereby preventing the occurrence of cracks in the magnetic core. Furthermore, by standardizing and preparing a combination of intermediate magnetic core, gap spacer, and resin molding, assembly work can be performed easily.As a result, multi-stage magnetic gaps can be easily configured, resulting in high reliability and high quality.・A high-performance, compact converter transformer can be provided at low cost.

Embodiment Hereinafter, one embodiment of the converter transformer of the present invention will be described with reference to the drawings.

FIG. 1 shows a cross-sectional view of a converter transformer according to the present invention. Basically, in the configuration shown in Figure 1,
Components that are the same as those in the conventional configuration in FIG. 5 are given the same numbers and their explanations will be omitted.

In Fig. 1, the major difference from the conventional one is the intermediate magnetic core 2.
A magnetic gap is formed by the combination of the resin molded body 5 having an H-shaped cross section and the magnetic core 1, and FIG. 3 shows a partial view of the magnetic gap portion in an embodiment of the present invention.

To explain the configuration in Fig. 1, a pair of magnetic cores 1 forming a closed magnetic path are assembled from one side into a bobbin 3 prepared by winding a winding 4, a resin molded 5° intermediate magnetic core 2 is sequentially assembled, and finally Incorporate the other magnetic core 1 to complete the process. To further explain the configuration of the magnetic gap portion using FIG. 3, in the figure, the magnetic core convex portion 1b, the resin molded body 5, and the intermediate magnetic core 2 are fixed by a method such as adhesion, but the magnetic core convex portion 1a and the resin molded The body 5 has a structure in which it is not fixed and has a small gap (A-A' plane in the figure).

The operation of the converter transformer configured as described above will be explained below with reference to FIGS. 3 and 4. first,
The magnetic gear part dimension G1 is formed by the thickness of the resin molded body 5 that fits into the convex part 1b of the magnetic core 1 shown in FIG. is formed. Here, the resin molded body 5 has an H-shaped cross section and is fitted into the convex portion of the magnetic core 1, so that it does not move. Moreover, since the intermediate magnetic core 2 is incorporated into the recess of the resin molded body 5, it does not move. In other words, magnetic core 1 and intermediate magnetic core 2
The relative positional relationship is fixed via the resin molded body 5. Furthermore, since the magnetic gap dimensions of Gl and G2 each correspond to the magnetic gap dimension of 1/2G shown in Fig. 4, the spread of leakage magnetic flux distribution is reduced, reducing eddy current loss. I can do it. Further, the resin molded body 5 and the magnetic core convex portion 1a are arranged along the line A-A' in FIG.
Since it is not fixed on the surface and has a small gap, it is possible to absorb differences in coefficient of linear expansion.

As described above, according to this embodiment, by incorporating the resin molded body 5 having an H-shaped cross section and incorporating the plate-shaped intermediate magnetic core 2 into the magnetic gap 6, it is possible to prevent the intermediate magnetic core 2 from moving. Adjustment work during formation and transformer assembly work can be easily performed, and magnetic performance accuracy can also be improved. Furthermore, since the structure is such that one end of the resin molded body 5 and the magnetic core 1 are not fixed to each other, reliability is also improved.

In the embodiment, the cross-sectional shape of the resin molded body 5 is H-shaped, but the same effect can be obtained even if it is concave.Furthermore, the resin molded body 5 may be made of a film or the like. Furthermore, in the example,
Although two magnetic gaps were constructed using one intermediate magnetic core 2, it is better to use two or more intermediate magnetic cores 2 to set the size of each magnetic gap as small as possible, as shown in Fig. 2a. It goes without saying that the melt current loss due to leakage magnetic flux can be further reduced, and the effect of reducing heat generation in the windings is greater. In addition, if you prepare any magnetic gap dimensions in advance using various combinations of gap spacers and intermediate magnetic cores as shown in Figure 2, it will have a very large effect in terms of management and standardization. .

Effects of the Invention As described above, according to the present invention, a magnetic gap is formed in the magnetic leg in which the winding of the closed magnetic circuit core is incorporated, and a plate-shaped intermediate magnetic core is incorporated in the magnetic gap, which is a resin having an H-shaped or concave cross section. By incorporating a molded body and forming at least two or more magnetic gaps without fixing one end of the resin molded body to the magnetic core, it is possible to prevent the intermediate magnetic core from moving, making it easier to adjust when forming the magnetic gap. This makes it easier to assemble the converter transformer, and improves magnetic performance accuracy.

■ Because one end of the resin molded body is not fixed to the magnetic core,
It can absorb the difference in linear expansion rate between the outer leg and the middle leg,
Improved reliability.

■ By preparing various combinations of gap spacers and intermediate magnetic cores in advance, any magnetic gap size can be accommodated, which is advantageous in terms of management and standardization.

(2) to (2) can easily provide a multi-stage magnetic gap, which has traditionally been problematic in terms of manufacturing, making it possible to reduce loss and downsize.

As a result, it is possible to provide a small converter transformer with high reliability, high quality, and high performance at a low cost, which is of great industrial value.

[Brief explanation of drawings]

Fig. 1 is a sectional view of a converter transformer showing an embodiment of the present invention, Fig. 2 is a sectional view of a converter transformer showing a second embodiment of the invention, and Fig. 3 is a sectional view of a conventional converter transformer. Cross-sectional view, 61st...Magnetic core, 2...
...Intermediate magnetic core, 3...Bobbin, 4...
- Winding wire, 5...Resin molded body, 6...Magnetic gap.

Claims (1)

[Claims] A magnetic gap is formed in the magnetic leg in which the winding of the closed magnetic circuit core is incorporated, and a resin molded body having an H-shaped or concave cross section incorporating a plate-shaped intermediate magnetic core is built into this magnetic gap, and one side of the resin molded body is A converter transformer whose ends are not fixed to the magnetic core and have at least two magnetic gaps formed.