JPS6031090B2 - Outer iron type core transformer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an outer iron core transformer having an outer iron core made of ferrite.

A large number of external iron core transformers of this type are required in communication technology transmission systems, but the electrical characteristics of the transformers must be allowed to vary only within a relatively narrow range.

The object of the invention is to design a transformer of the above-mentioned type in such a way that the external iron core has significantly smaller dimensions and the electrical characteristics of the transformer have optimum values.

The above problem can be solved by the present invention as follows.

That is, the outer iron type core is made to have a substantially flat rectangular parallelepiped shape, and the height of the cavity formed between the two cover parts is equal to twice the protruding length of the central part of the core half part. so that the height of the cavity does not exceed the thickness of one cover part, and the circumferential wall part has two slit-shaped fracture points on the longitudinal side of each core half, and the broken parts are: A sekiguchi is configured to extend in a direction transverse to the axis of the central part of the outer iron type core formed by combining the two core halves,
The thin plate has a protruding portion that engages with the closed portion. The advantage obtained with such an arrangement of the transformer according to the invention is that it can be made extremely compact with respect to its dimensions and its weight, without this being accompanied by a significant deterioration of its electrical properties.

Transformers of this type are therefore particularly suitable for integration into layered circuits arranged on substrates. The invention will now be explained in detail with reference to the figures. As shown individually in the figures, the outer iron core of the transformer has an approximately flat rectangular parallelepiped external shape or outline.
It is assembled from two identical core halves 2, 3 formed in one piece, which are joined to each other without any gaps perpendicular to the axis of the cylindrical projection 4 as the central part.

In each core half, the projection 4 is surrounded by a peripheral wall 7 forming a substantially rotationally symmetrical cavity 6 surrounding said projection. On the longitudinal side 8 of each core half 2, 3, the peripheral wall 7 has a slit-shaped break point 9. When the two core halves are put together, this fractured part constitutes a slit-shaped opening □ in the outer iron type core.

The outer iron type core is limited in the axial direction of the protrusion 4 by core cover parts 10 and 11. Furthermore, according to the invention, in order to obtain optimum transmission characteristics, the core cover portion 10,
The thickness of 11 is selected to be at least twice the length of the protrusion 4 inside the cavity 6 surrounded by the peripheral wall 7 . The transformer windings 12, 13 are each mounted on a thin composite sheet 14.

In this case, this winding sheet 14 has a contour that is precisely adapted to the shape of the cavity 6 and has an overhang 15 that fits into the opening □ formed by the defective location 9 of the peripheral wall 7. are doing.
One of the overhanging parts 15 of the winding thin plate assembly 14 overhangs the contour of the outer iron core 1 and has a finger 1.
An extension 16 formed at 7 is provided. The overhang 15 of the winding sheet 14 with the extension 16 is provided with a strip-shaped metal-plated section 18, which metallized strip 18 is connected to the individual fingers 17 of the extension 16. It extends along the The metallized strips 18 are directly connected to the transformer windings 12, 13 as winding ends, winding beginnings, or winding taps, and are connected in the manner of parentheses (see, for example, FIG. 2) to the substrate 20. The outer iron core windings and substrate 20 are assembled by soldering directly to the metallized surface area 19.
forming connections between layered circuits placed in the As cover layer and intermediate layer, an insulating sheet 21 of approximately the same shape as the winding sheet 14 is provided, the thickness, dielectric constant and elasticity of which are selected in accordance with the requirements.

This insulating sheet 21 can also, for example, be covered with an associated metallization 23 which, like the insulating sheet 21a, simply has an interruption running along the radius of the cavity 6;
Similarly, connecting fingers 17 may also be provided. In this case, such an insulating sheet 21a is used as a shielding surface between two transformer windings. As shown in FIG. 1, the thin winding plates 14 and the thin insulating plates 21a and 21a are constructed into a stack of thin plates that completely fills the cavity 6 of the outer iron core.

With the above-described configuration, the protruding length of the central member 4 of the core half is significantly shortened, so that the magnetic resistance of this portion is significantly reduced. The height of the cavity is made as low as possible compared to the thickness of the cover.

The core material is a material having a favorable magnetic permeability in the frequency range of the transmitted signal, e.g. for its lower cutoff frequency.
used.

Next, the excellent transmission characteristics of the transformer of the present invention having the above-mentioned structural requirements and magnetic permeability will be shown using actually measured data.

Of the five outer iron core transformers shown in Figures 3a to 3e, Figures 3a and 3b are known transformers, and Figures 3c, 3d, and 3e are known transformers. This is an outer iron type core transformer according to the present invention. In each drawing, a is the core thickness, b
indicates the height of the cavity. In Figures 3c, 3d, and 3e, core cover thickness (a-b)/2≧cavity height b
, has been selected. FIG. 4 shows experimental data showing the relationship between the output level PN and the strain attenuation KD for each of the outer iron core transformers shown in FIGS. 3a to 3e. In this case, A, B, C, D, and E indicate the characteristic curves of the transformers of FIGS. 3a, 3b, 3c, 3d, and 3e, respectively. As shown, C, D,
In the transformer E, the amount of strain attenuation is significantly increased compared to known transformers, that is, the distortion rate is reduced. FIG. 5 shows experimental data showing changes in admittance with respect to frequency of an outer iron core transformer.

First, the values of conductance 1/R and susceptance 1/x when each transformer is operated at 60 MHZ are shown at the upper end of each curve. Next, change the frequency to lower to 4M
The conductance and susceptance values of each transformer E, D, C at HZ are shown at the lower end of each curve. On the other hand, in the curves B and A, the values of susceptance and conductance when the frequency is MHZ and mother HHZ are shown at the lower points of each curve.
Although the frequency is not lowered to 4MH2, the susceptance value fluctuates greatly. Therefore, in the outer iron type core transformers E, D, and C of the present invention, compared to the conventional transformers B and A, the fluctuations in the susceptance value are more consistent, and the fluctuations in the admittance value are significantly smaller by 4. This experimental data is shown below.

[Brief explanation of the drawing]

The figures are for explaining an embodiment of the present invention, and FIG. 1 is an exploded perspective diagram of an embodiment of the outer iron core transformer of the present invention, and FIG. 2 is an outer iron core transformer arranged on a board. Fig. 3a, Fig. 3b, Fig. 3c, Fig. 3b.
Fig. 3e is a plan view of the outer iron type core, Fig. 4 is a diagram of experimental data showing the strain attenuation of each transformer, and Fig. 5 is experimental data showing the fluctuation of admittance with respect to frequency in the transmission frequency domain. FIG. 1... Outer iron type core, 2, 3... Core half, 4... Central part, 6... Hollow, 7...
... Peripheral wall part, 8 ... Longitudinal side surface, 9 ...
・Broken location, 10, 1 1... Core cover part,
12, 13... Winding wire, 14... Winding thin plate, 15
...Protrusion part, 16... Extension part, 17.
...Finger, 18...Strip strip, 19.
. . . Metallized surface area, 20 . . . Substrate, 21 .
... Insulating thin plate, 22 ... Molded block. Fig. 3A Fig. 3B Fig. l Fig. 2 Fig. 3C Fig. 3E Fig. 3D Fig. 5

Claims (1)

[Claims] 1. A core transformer having a core made of ferrite, which core is composed of two identical core halves 2, 3 that are fitted together without any gaps, Each of the two core halves is integrally formed of a cover part 10, 11, a central part 4 provided at the center of the cover part 10, 11 and protruding from the cover, and a peripheral wall part 7 surrounding the central part 4. The peripheral wall portion 7 has the same height as the central portion 4, and the outer iron type core has at least two
Two winding sheets 14 are provided, each of which has a winding 12, 13 mounted on a thin insulating sheet, together with unwinding insulating sheets 21, 21a. It is arranged in the cavity 6 of the outer iron type core inside the peripheral wall part 7, in which case the central part 4 of the outer iron type core half parts 2, 3 passes through the hole in the center of the thin plate. In an outer iron core transformer having an outer iron core made of ferrite, the outer iron core 1 has a substantially flat rectangular parallelepiped shape, and a cavity 6 is formed between two cover parts 10 and 11. The height of the hollow part 6 is set to be equal to twice the protruding length of the central part 4 of the core half parts 2 and 3, and the height of the hollow part 6 is set to 1.
On the longitudinal side 8 of each core half, the circumferential wall 7 has two slit-like breaks 9, which break the two core halves. An overhanging portion 15 is formed so as to form an opening extending in a direction transverse to the axial direction of the central portion 4 of the outer iron type core formed by combining the thin plates 14, 21, and 21a into the opening.
An outer iron core transformer having an outer iron core made of ferrite.