JPH04294510A - Transformer for coupling impedance - Google Patents

Abstract

PURPOSE:To obtain a transformer which is suppressed in fluctuation of the impedance conversion characteristic by suppressing the fluctuation of the winding shape and dimension of metallic wires wound around a magnetic body. CONSTITUTION:In this transformer for coupling impedance which is constituted by winding metallic wires 2 and 4 around a magnetic body 1, metallic wires 3 and 4 made of a shape memory alloy wherein a prescribed shape is stored at a set temperature are integrally wound together with the wires 2 and 4 around at least the part of the magnetic body 1 where the wires 2 and 4 are wound. When the temperature of the magnetic body 1 is set to the set temperature after the wire 2 and 4 are wound around the magnetic body 1, the wires 3 and 5 return to their original shapes and, at the same time, the wires are deformed to desired wound states. Therefore, the fluctuation of the wound shape and dimension of the wires 2 and 4 can be eliminated.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an impedance coupling transformer, and more particularly to an impedance coupling transformer in which variations in impedance conversion characteristics are reduced.

0002

2. Description of the Related Art Conventionally, in this type of impedance coupling transformer, as shown in FIG. 4, metal wires 2 and 4 for input and output are wound around a ring-shaped magnetic body 1. It is configured such that impedance conversion can be performed by utilizing the fact that the impedance on the input side and the output side differ depending on the turn ratio of the output metal wire 4. In such a transformer, the diameter of the coils of the metal wires 2 and 4 wound around the magnetic body 1 must be constant in order to eliminate variations in impedance conversion characteristics. The metal wires 2 and 4 are wound so as to be in close contact with the metal wires 2 and 4. Similarly, the metal wires are wound so that the distance between the individual transformers is a certain value.

0003

[Problems to be Solved by the Invention] In this conventional impedance coupling transformer, even if an attempt is made to wind the metal wires 2 and 4 tightly around the magnetic body 1, due to the springiness of the metal wires, in reality, they are not completely tightly wound. It is difficult to wrap it around. In addition, in this case, it is necessary to wind the metal wires 2 and 4 with a constant force, but since this winding work is usually done manually, there may be differences in working time or different workers. It is difficult to ensure a constant force, and variations are inevitable. Similarly, even when the intervals between the metal wires are made constant, there is a large variation in the distance between the metal wires when done manually, as described above. These variations are reflected in variations in the impedance conversion characteristics, which poses a major problem in stabilizing the characteristics of a device using the transformer. An object of the present invention is to provide a transformer in which variations in the winding shape and dimensions of metal wires are suppressed, and variations in impedance conversion characteristics are reduced.

0004

[Means for Solving the Problems] The impedance coupling transformer of the present invention includes a metal wire made of a shape memory alloy that has a predetermined shape memorized at a certain set temperature in at least the part of the metal wire wound around the magnetic material. are installed in an integrated manner. For example, the metal wire is covered with a resin that covers the metal wire and is integrated into the metal wire.

[0005]

[Operation] According to the present invention, by winding a metal wire around a magnetic material and bringing it to a set temperature, the metal wire of the shape memory alloy is deformed into a memorized shape, and the metal wire is also deformed accordingly. and then rolled into the desired state.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, the present invention will be explained with reference to the drawings. FIG. 1 is a plan view showing a first embodiment of the impedance coupling transformer of the present invention, which has a toroidal core 1 made of an annular ferrite material with a circular cross section as a magnetic material, and has an input side on one side. A first metal wire 2 made of polyurethane-coated copper wire is wound in four turns. Further, on the other side of the toroidal core 1, a second metal wire 4 made of polyurethane-coated copper wire is wound twice as an output side. This transformer has a wire winding ratio of 2:1 and can perform impedance conversion with an impedance ratio of 4:1.

The first metal wire 2 and the second metal wire 4 are coated with polyurethane resin, and the shape shaping metal wires 3 and 5 are electrically insulated from each metal wire. It is glued along its length. The shape-shaping metal wires 3 and 5 have shapes memorized in advance so that they become coiled with a wire spacing a and a radius b at a specified temperature t0° C., as shown in FIGS. 2(a) and 2(b). Constructed of memory alloy. Further, it is preferable that these metal wires 3 and 5 are coated with the polyurethane. Note that the ends of each metal wire 2 and 4 are coated with a polyurethane insulating coating of, for example, 2 mm.
They are peeled off and exposed, forming input terminals and output terminals, respectively.

Therefore, in manufacturing this transformer, the metal wires 2 and 4 to which the metal wires 3 and 5 are bonded are wound around the toroidal core 1, respectively. After that, the entire body is heated to the specified temperature t.
By performing heat treatment at 0.degree. C., the metal wires 3 and 5 are restored to the memorized shape of FIG. 2. At this time, the metal wire 3,
5 simultaneously deforms the metal wires 2 and 4 into the memorized shape. This shape is equal to the cross-sectional diameter of the toroidal core 1 and is set at regular intervals, so that each metal wire 2, 4
are in close contact with the surface of the toroidal core 1 and wound at regular intervals. As a result, the metal wire 2
, 4 at a constant diameter and at a constant interval,
Variations in impedance conversion characteristics are suppressed.

FIG. 3 is a plan view of a second embodiment of the present invention. The basic structure and manufacturing method thereof are the same as in the first embodiment, but in this embodiment, protrusions 1a and 1b are provided on one side and the other side of the inner peripheral surface of the toroidal core 1, respectively. The protrusions 1a and 1b are made smaller than the winding interval of the metal wires 2 and 4, respectively, and are provided at locations corresponding to the respective end positions of the metal wires 2 and 4. In this configuration, by hooking and winding the first winding portions of the metal wires 2 and 4 on the projections 1a and 1b, respectively, the circumference of the toroidal core 1 of the first metal wire 2 and the second metal wire 4 is This has the effect of reducing variations in relative positions in the directions.

0010

Effects of the Invention As explained above, the impedance coupling transformer of the present invention has a metal wire made of a shape memory alloy integrally attached to the part of the metal wire wound around the magnetic material. Restoring the shape of the metal wire after winding the wire has the effect of reducing variations in the winding shape of the metal wire and reducing variations in impedance conversion characteristics.

[Brief explanation of drawings]

FIG. 1 is a plan view of a first embodiment of a transformer of the present invention.

FIG. 2 is a diagram showing a memorized shape of a metal wire (shape memory alloy), in which (a) is a plan view and (b) is a cross-sectional view taken along line A-A.

FIG. 3 is a plan view of a second embodiment of the invention.

FIG. 4 is a plan view of a conventional transformer.

[Explanation of symbols]

1 Toroidal core 2,4 Metal wire 3,5 Metal wire (shape memory alloy)

Claims (2)

[Claims] 1. In an impedance coupling transformer comprising first and second metal wires wound around a magnetic material, at least the portion of the metal wire wound around the magnetic material has a predetermined temperature at a certain set temperature. An impedance coupling transformer characterized by integrally extending a metal wire made of a shape memory alloy whose shape is memorized. [Claim 2] Claim 1, wherein the metal wire is coated with a resin that covers the metal wire and is integrated with the metal wire.
A transformer for impedance coupling.