JPH0735369Y2 - Trance - Google Patents

Description

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

2. Description of the Related Art In recent years, transformers have been reduced in size, but temperature reduction measures are considered important for downsizing.

The conventional transformer will be described below. FIG. 4 is a sectional view of a conventional transformer. In Figure 4
15 is an EE type magnetic core, 16 is a bobbin, 17 is a coil, 18 is a magnetic core 15
It is the gap part provided in. FIG. 5 is a partial view of the gap of the conventional transformer, and shows transformers having different gap sizes of (a), (b), and (c) in the order: large, medium, and small. In FIG. 5, 15 is a magnetic core, 18 is a gap part, l ₁ ,
l ₂ and l ₃ indicate the respective gap dimensions. FIG. 6 is a cross-sectional view of a conventional transformer showing the relationship between the leakage magnetic flux and the coil. In FIG. 6, 19 is a leakage magnetic flux and 17 is a coil.

The structure will be described with reference to FIG. 4. The coil 17 is wound around the core of the bobbin 16. It should be noted that an arbitrary number of coils may be prepared for winding according to the number of coils (not shown). Next, the magnetic core 15 provided with the gap 18 is incorporated and completed.

In the transformer configured as described above, as shown in FIG. 6, the leakage magnetic flux 19 leaking from the gap 18 interlinks the coil 17 and heat is generated due to the eddy current loss inside the coil. The butt portion was subjected to a simulation analysis by a finite element method or the like, and the distribution of the leakage magnetic flux 19 was formed as a curved surface so as not to interlink the coil 17 to reduce heat generation due to eddy current loss.

Further, in the analysis by the sawtooth finite element method or the like, the leakage magnetic flux increases as it approaches the abutting surface of the gap portion 18, but the magnetic flux passing through the inside of the magnetic core 15 decreases in inverse proportion to this. In addition, the element for obtaining the curved surface shape of the butt portion for obtaining the minimum required magnetic core cross-sectional area was added, and the weight and cost were reduced by reducing the usage of one hole of the magnetic core.

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention However, in the above-described conventional configuration, heat is not suppressed in the portion of the coil 17 close to the gap 18, and winding is performed while avoiding the adjacent portion, or the conductor disconnection of the copper wire. It was necessary to suppress heat generation by enlarging the area and lowering the DC resistance, and adopting litz wire at high frequencies.
All of these have drawbacks such as a large transformer shape and high cost. Further, as the biggest drawback, as shown in FIG. 5, for example, in the same magnetic core size, as shown in (a), (b), (c),
When configuring various transformers with different gap dimensions of the gap 18 such as l ₁₁ to l ₁₃ , since the middle foot abutment part is finished with a curved surface, it is not possible to use gap machining by plane polishing, so the gap dimension It is difficult to standardize as a transformer because it requires a magnetic core mold for each, or even if it is the same magnetic core mold, it is necessary to have a structure in which the mold of the curved surface part can be exchanged It is not suitable, and as a high frequency transformer, there is a problem that it is not possible to easily adjust the inductance value, the magnetic saturation property, etc. by a gap.

The present invention solves the above-mentioned conventional problems, provides a transformer that minimizes the influence of leakage magnetic flux on the coil, is most suitable for high-quality production, and can easily set the gap size and is inexpensive. That is the purpose.

Means for Solving the Problem In order to solve this problem, a transformer of the present invention is provided with an intermediate magnetic core having a plurality of butting surfaces on a magnetic leg around which a coil of a closed magnetic circuit core is wound. Each of the portions forming the surface is curved.

Action With this configuration, the size of each gap is reduced, so the leakage flux distribution is reduced, heat generated by the eddy current generated in the coil is suppressed to a minimum, and by using various intermediate magnetic cores, It is possible to easily obtain an arbitrary gap size while the abutting surface is curved.

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

FIG. 1 is a sectional view of a transformer according to an embodiment of the present invention. In FIG. 1, reference numeral 1 is an EE type magnetic core, and the portion forming the abutting surface is finished into a curved surface shape according to the gap size and the cross-sectional area by simulation analysis by the finite element method or the like. Reference numeral 2 denotes an intermediate magnetic core provided between the magnetic cores 1, and the abutting surfaces on both sides are finished in a curved shape like the magnetic core 1. 3 is a bobbin, 4 is a coil, and 5 is a gap spacer provided for fixing the position of the intermediate magnetic core 2 between the magnetic cores 1, and is made of chloroprene, neoprene, silicone-based non-magnetic material having rubber-like elasticity. Has been formed.

FIG. 2 is a partial view of a gap of a transformer according to an embodiment of the present invention, showing transformers having large, medium and small gap sizes in the order of (a), (b) and (c). In FIG. 2, 1 is a magnetic core, 2 is an intermediate magnetic core, and l _{1 to} l ₆ are respective gap sizes. FIG. 3 is a sectional view of the transformer according to the embodiment of the present invention, showing the relationship between the leakage magnetic flux and the coil. In FIG. 3, 6 is a leakage magnetic flux and 4 is a coil.

The configuration will be described with reference to FIG. 1. The coil 4 similar to the conventional one is wound around the pobbin 3. Next, the magnetic core 1 is assembled from one side, and the gap spacer 5, the intermediate magnetic core 2, and the gap spacer 5 are inserted in this order into the winding core of the bobbin 3. Further, the other magnetic core 1 is incorporated and completed.

The operation of the transformer configured as described above will be described below. First, according to this embodiment, since the intermediate magnetic core 2 is provided between the magnetic cores 1, the inductance value,
When the saturation characteristic represented by the DC superposition characteristic is the same as the conventional one, the gap size can be reduced to about 1/2. For example, when the gap dimension l ₁₁ is 2 mm in FIG. 5A of the conventional example, when the same inductance value and magnetic saturation characteristics are set in FIG. 2A of one embodiment of the present invention, the gap dimension is ₁₁ mm. Is both l ₁ and l ₂ ,
About 1 mm is enough. As a result, the influence of the leakage magnetic flux 6 on the coil 4 in FIG. 3 is minimized, and the heat generation of the coil 4 can be reduced.

Further, when the gap size is arbitrarily set, as shown in FIGS. 2 (a), (b) and (c), the magnetic cores 1 are exactly the same, and the respective gap sizes l _{1 to} l ₆ are set. Accordingly, the intermediate magnetic core 2 may be prepared. In this case, since the length of the intermediate magnetic core 2 only changes, for example, in the case of a magnetic core manufactured by press molding such as a dust core or a high frequency ferrite core, only stroke adjustment of the press die is required. It is possible to manufacture by using, the mold can be shared, the intermediate magnetic cores 2 having different lengths can be easily prepared, and the magnetic core mold for each gap unlike the conventional type is not required, and the arbitrary gap size can be set. Become.

Next, in FIG. 1, since a gap spacer 5 made of a rubber-like non-magnetic material is inserted in the gap, the magnetic core 1
If the two outer legs are abutted and fixed, the two gap spacers 5 are set in the center between the magnetic cores 1 without any fine adjustment due to the uniform elasticity of the two gap spacers 5, and the two gaps have the same size. Thereby, the leakage magnetic flux leaking from the two gaps becomes uniform, and the partial heat generation of the coil 4 can be prevented.

Further, since the gap spacer 5 absorbs the dimensional accuracy variations of the magnetic core 1 and the intermediate magnetic core 2 in the bobbin winding direction,
The intermediate magnetic core 2 does not rattle.

In the embodiment, one intermediate magnetic core 2 is used and the gap is set to 2
Although the number of gaps is increased by using a plurality of intermediate magnetic cores 2 as necessary, it is possible to reduce the influence of the leakage magnetic flux on the coil 4 by setting the gap size as small as possible. Needless to say.

Effects of the Invention As described above, according to the present invention, a magnetic leg for winding a coil of a closed magnetic circuit core is newly provided with an intermediate magnetic core to reduce the gap size to 1/2, thereby generating heat due to eddy current loss of the transformer coil. It is possible to reduce the temperature by using the high-cost material because the conductor cross-section area of the copper wire is not increased and the litz wire is not used in the case of high frequency to reduce the temperature. Eliminates and is economical. Also, by adopting this intermediate core, it was difficult to standardize a transformer with a curved butting surface of the core in the past, but various intermediate cores can be easily prepared and the gap size can be set arbitrarily, so standardization of the transformer is possible. It is possible to expand the application to various electronic devices. In addition, by fixing the intermediate core with a rubber-like gap, the gap size can be easily made uniform, partial heat generation of the coil due to gap size variation is eliminated, and rattling of the intermediate core can be prevented. It is possible to realize an excellent transformer.

[Brief description of drawings]

FIG. 1 is a sectional view showing an embodiment of the transformer of the present invention, FIG. 2 is a partial sectional view of a gap of the transformer according to the embodiment of the present invention, and FIG. 3 is a sectional view of an embodiment of the transformer of the present invention. Fig. 4 is a sectional view of a conventional transformer, Fig. 5 is a partial sectional view of a gap of a conventional transformer, and Fig. 6 is a leakage flux of a conventional transformer. It is sectional drawing which showed the relationship with a coil. 1 ... magnetic core, 2 ... intermediate magnetic core, 3 ... bobbin, 4 ... coil, 5 ... gap spacer.

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Toshiyuki Nakata 1006 Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. (56) Reference JP-A-2-290005 (JP, A)

Claims (3)

[Scope of utility model registration request] 1. A transformer in which a magnetic leg around which a coil of a closed magnetic circuit core is wound is provided with an intermediate magnetic core so as to have a plurality of abutting faces, and the portions forming the abutting faces are curved. 2. A transformer according to claim 1, wherein a plurality of butting surfaces have the same gap size. 3. The transformer according to claim 1, wherein elastic gap spacers are arranged on both sides of the central magnetic core.