JPS59184507A - Transformer and manufacture thereof - Google Patents

Abstract

PURPOSE:To contrive miniaturization and lightening in weight of a transformer by improving a volumetric efficiency by a method wherein a long tape-form member whose width becomes narrower gradually from the center toward the both ends consisting of a high-permeability material is wound into a rectangular shape and it is cut by its longitudinal side so as to form a pair of C-shape cut cores which are inserted in a bobbin holes. CONSTITUTION:A strip-form member 1 consisting of a high-permeability material such as silica steel plate has a width which becomes so narrower gradually from the center toward the both ends that a right-angle cross section of magnetic path becomes nearly a circle when it is rolled up on to a jig so as to form a loop core 2. Next, the tape- form member 1 is rolled up on a proper jig into a rectangular shape so as to form the loop core 2, which is subjected to heat treatment and is impregnated with an insulating varnish which is then dried to be hardened. This loop core 2 is cut by about the center of its longitudinal side and the cut planes are ground so as to form a pair of C-shaped cut cores 2a and 2b. Then coils 3 and 3' are fabricated by winding the desired wires 5 and 5' on cylindrical coil bobbins 4 and 4' which fit for said cores 2a and 2b and these coils are inserted in the both ends of the C-shape cut cores 2a and 2b.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a novel transformer using a C-cut core and a method for manufacturing the same.

As a wound iron core used in a transformer, a C-shaped cut core whose cross section perpendicular to the magnetic path is rectangular as defined in JIS standard C6442 is well known and widely used.

A transformer using a C-shaped cut core with a rectangular cross-section at right angles to the magnetic path has large iron losses and leakage magnetic flux, low efficiency, and has the ll1R problem of causing induction disturbances to the outside.

For this purpose, we use a strip whose width becomes narrower from the center to both ends, and wind it up to form a loop core whose cross section perpendicular to the magnetic path is circular. (2) Leave it as it is without cutting it. A known method is to manufacture a transformer by combining two semi-cylindrical coil bobbins with the loop core sandwiched between them, and then rotating the combined cylindrical bobbin to wind the coil.

In this case, a cylindrical bobbin must be used to wind the wire by rotating it, so if a loop core with a rectangular cross section at right angles to the magnetic path is used, the bobbin cannot be rotated smoothly, and the loop・An air gap is created between the core and the bobbin, resulting in a large amount of leakage magnetic flux and a low effective magnetic permeability. For this reason,
It uses a loop core whose cross section perpendicular to the magnetic path is circular.

However, a transformer manufactured by winding a loop core with a circular cross-section perpendicular to the channel using a matching bobbin has excellent characteristics such as low leakage magnetic flux and high effective magnetic permeability. When winding is performed by rotating the bobbin, the iron core must be inserted into the mating bobbin and the winding must be performed by rotating the bobbin, resulting in poor work efficiency and the winding equipment being complicated and expensive. Become. In addition, in this type of transformer (3), it is necessary to make the coils on the negative side and secondary side completely symmetrical, but when the rotary roller is brought into contact with the bobbin and the bobbin is rotated, it is necessary to There was a point 1lIIB where the bobbin slipped and the rotation was not transmitted accurately, making the number of turns of the coil unstable.

Additionally, since this transformer did not have an insulating face impregnated into the loop core, its characteristics deteriorated when vibration and impact were applied, so care was required when handling it.

It was believed that the advantage of transformers using this loop core came from using the core in its loop shape without cutting it, so those who attempted to cut this circular cross-section core were There wasn't.

However, the present inventors believe that the advantage of this loop core transformer is not that the core is loop-shaped, but that the cross section perpendicular to the magnetic path is circular. The present invention was completed based on the discovery that even if the core is cut and used as a C-cut core, its characteristics are not impaired in any way.

(4) In other words, in the past, it was thought that the core should have a circular cross section in order to wind the coil as closely as possible around the loop core and reduce the gap between the core and the bobbin. The shape not only makes it easier to wind the coil, but also
This has the effect of reducing leakage magnetic flux.

In other words, the effect of suppressing leakage magnetic flux, which was conventionally thought to be due to making the core into a loop shape without cutting it, is actually not due to making the core into a loop shape, but due to the fact that the cross section of the core is circular. It was something.

When the cross section of the core is circular, the magnetic flux density in the cross section of the core becomes uniform, so that leakage magnetic flux does not occur, and even if the core is cut, there is no adverse effect.

The gist of the present invention is to form a long strip made of a material with high magnetic permeability and whose width becomes narrower from the center to both ends, and to wind the strip into a rectangular shape. , a step of forming a loop core with a substantially circular cross section perpendicular to the magnetic path, a step of heat-treating the loop core described in (5) above by a conventional method, and impregnating the heat-treated loop core with an insulating varnish and drying it. a step of cutting a loop core impregnated with an insulating face along its long side and polishing the cut surfaces to form a pair of C-shaped cut cores; A step of manufacturing primary and secondary coils by a conventional method using a bobbin and desired wire, and inserting both ends of the pair of C-shaped cut cores into the bobbin holes of the primary and secondary coils, respectively. The purpose of the present invention is to manufacture a transformer by a method consisting of the steps of inserting the transformer into the transformer and holding the transformer properly facing each other.

The present invention will be described in detail below based on the drawings.

FIG. 1 is a developed plan view of a strip forming the wound iron core of a transformer according to the present invention, FIG. 2 is a plan view of a loop core formed by winding the strip shown in FIG. 1 into a rectangular shape, and FIG. Figure 3 is a cross-sectional view taken along line A-A in Figure 2, and Figure 4 is a perspective view of a pair of C-shaped cut cores obtained by cutting the loop core shown in Figure 2 at the center of its long side. Figure 5 is a perspective view of a pair of coils with a wire (6) wound around a coil bobbin, and Figure 6 shows the cut core shown in Figure 4 inserted into the pair of coils shown in Figure 5 and held. FIG. 7 is a plan view showing an embodiment of the transformer according to the present invention manufactured by the above method, and FIG. 7 is a front view thereof.

In FIGS. 1 to 7, 1 is a strip forming a loop core, 2 is a loop core, and 2a and 2b are a pair of uncut strips.
The core, 3.3' is a pair of coils, 4.4 is a coil bobbin, 5.5 is a winding, 6 is a base, and 7.7 is a fixture.

The strip 1 forming the loop core 2 is made of a high magnetic permeability material such as a silicon steel plate.

The strip 1 is wound in order from the center to both ends so that when the loop core 2 shown in FIG. Its width is narrowing.

In addition, in FIG. 1, the longitudinal direction of the strip-shaped body 1 is appropriately reduced.

Next, the strip 1 is wound up into a rectangular shape on a suitable jig to form the loop core 2 (7) shown in FIGS. 2 and 3.

In order to cause the formed loop core 2 to exhibit predetermined magnetic properties, heat treatment is performed under predetermined conditions depending on the material.

Next, the loop core 2 subjected to the above heat treatment is impregnated with an insulating varnish and dried.

The loop core 2 with the insulating face impregnated and dried is cut approximately at the center of its long side, and the cut surfaces are polished to form a pair of C-shaped cut cores 2a and 2b shown in FIG. 4.

A desired wire 5.5' is wound around a cylindrical coil bobbin 4.4' that fits the pair of C-shaped cut cores 2a and 2b, to produce a coil 3.3' shown in FIG.

In this case, each coil bobbin 4,4' can be individually attached to a suitable coil winding device and wound thereon. Further, since the bobbin 4.4' of this coil 3.3' is cylindrical, it is easy to wind the wire 5.5', and a predetermined number of turns can be obtained with the shortest wire, making the transformer lightweight.

(8) Next, insert the coils 3.3' into both ends of the pair of C-shaped cut cores 2a and 2b, hold them facing each other correctly, and attach them to the base 6 using the fixtures 7.7. The transformer shown in FIGS. 6 and 7 is completed.

Since the transformer according to the present invention has little leakage magnetic flux, it is only necessary to attach a simple base 6 as shown in FIGS. 6 and 7, and there is no need for magnetic shielding when used as a power transformer for electronic equipment. do not have.

In addition, since the pair of C-shaped cut cores 2a and 2b have a substantially circular cross section perpendicular to their magnetic path, and the coil 3.3' is also cylindrical, the volumetric efficiency is extremely high (the transformer can be made smaller and lighter). .

Since the present invention is constructed as described above, the present invention has high efficiency and low magnetic flux leakage, so no induced noise is generated externally even without magnetic shielding.
Since the wound iron core is impregnated with insulating varnish, it is possible to provide a transformer that is strong against vibration and easy to handle.

[Brief explanation of the drawing]

(9) Fig. 1 is a developed plan view of a strip forming the wound iron core of the transformer according to the present invention, and Fig. 2 is a plan view of a loop core formed by winding the band shown in Fig. 1 into a rectangular shape. Figure 3 is a sectional view taken along line A-A in Figure 2, and Figure 4 is a pair of C-shaped cuts obtained by cutting the loop core shown in Figure 2 at the center of its long sides. Figure 5 is a perspective view of a pair of coils with the desired wire wound around the coil bobbin; Figure 6 is a perspective view of the C-shaped cut core shown in Figure 4 inserted into the pair of coils shown in Figure 5. FIG. 7 is a plan view showing an embodiment of the transformer according to the present invention manufactured by holding the transformer, and FIG. 7 is a front view thereof. 1------------・--11-------・----
Band-shaped body 2 forming the loop core -・・−・−・−・・−・−・・・・・−−−−1・−
Loop core 2a, 2b-・-・--・--・--・-・
Cut core 3.3'-・-1------・--・Pair of coils 6--・--1--
- Base patent applicant Toa Electronics Co., Ltd. (Gai-sha) Agent (7524) Shotabe Mogami (10) Figure 2 Figure 3 Figure 4

Claims (1)

[Claims] ■) A method for manufacturing a transformer characterized by comprising the steps described in (81) to (phantom) below. Step of forming a long belt-like body whose width is narrower. (bl) Step of winding the above-mentioned belt-like body into a rectangular shape to form a loop core whose cross section perpendicular to the magnetic path is approximately circular. (C1: Heat-treating the above-mentioned loop core by a conventional method. Process: +dl heat treated loop core impregnated with insulation face,
The process of drying. (The process of cutting a loop core impregnated with EL insulating varnish and drying it at approximately the center of its long side, and polishing the cut surface to form a pair of C-shaped cut cores. A process of manufacturing primary and secondary coils using a conventional method using a bobbin that fits the C-shaped cut core and the desired wire. (1) (Illustrated) A process of inserting into the bobbin holes of the primary and secondary coils and holding them facing each other correctly. 2) A C-shaped cut core whose cross section perpendicular to the magnetic path is approximately circular;
A transformer characterized by consisting of a pair of cylindrical coils.