JP2521845B2 - Curved ferrite core, manufacturing method thereof and jig for manufacturing the same - Google Patents

Description

TECHNICAL FIELD The present invention relates to a curved ferrite core, a method for manufacturing the same, and a jig for manufacturing the same.

<< Prior Art >> Generally, in manufacturing a ferrite core, it is formed into a flat plate shape, and in particular, it has been extremely important to accurately obtain flatness, levelness, linearity, etc. after firing. It was a technical issue.

Further, as an exceptionally special case, in the case of a ferrite core for deflection of a cathode ray tube or the like, a ferrite core powder press-molded into a predetermined curved surface shape is sintered while maintaining that shape.

By the way, recently, for example, as an induction heating core as a heat source, an electromagnetic cooker in which a ferrite core is embedded in the main body of the appliance has been proposed.

This kind of electromagnetic cooker consumes very little power to obtain the same amount of heat, and does not heat the surroundings, so it is particularly suitable as a cooking utensil in a place where a heat source such as gas cannot be used.

When burying a ferrite core in such an electromagnetic cooking utensil, a large number of flatly formed ferrite core pieces are arranged along the inner surface of the utensil and attached in a mosaic-like combination. There is.

However, such a method has the technical problems described below.

<< Problems to be Solved by the Invention >> That is, in the above-mentioned configuration, since a plurality of flat ferrite core pieces are attached to the surface of the appliance body, a sufficient curved surface cannot be obtained, and the thickness of the cooking appliance is also reduced. It was getting bigger.

In addition, in order to approach a pseudo curved surface, the ferrite core piece must be divided into small pieces according to the curvature of the device, and the number of divisions is large, so that there is a drawback that the number of attachment steps is large.

The present invention is to solve the above problems, and an object thereof is to provide a curved ferrite core having a curvature adapted to an arbitrary curved surface, a manufacturing method suitable for the curved ferrite core, and a jig for manufacturing the same. To do.

<Means for Solving the Problem> In order to achieve the above object, the present invention is a ferrite core piece for a curved ferrite core having an arbitrary outer shape and a predetermined thickness, which is continuous in the circumferential direction. Is a curved ferrite core divided into a large number of arbitrary line segments, the curved ferrite core is formed by combining the ferrite core pieces in a mosaic shape, curved ferrite core.

The curved ferrite core has a hemispherical shape,
The ferrite core piece can be formed into a substantially fan shape by a line segment passing through the central axis of the hemisphere.

Further, as a method for manufacturing the curved ferrite core,
Any external shape on the surface of the jig having the desired curved surface,
A ferrite powder molded body having a desired thickness is installed, and is sintered while being flexibly deformed into a curved surface along the curved surface of the jig by firing, and is then curved along the curved surface of the jig. Is formed, and a curved ferrite core is formed by combining a plurality of the ferrite core pieces.

In this case, the desired curved surface is hemispherical,
The molded body may be formed of a substantially fan-shaped one obtained by dividing the hemispherical shape into a plurality of line segments passing through the center thereof.

Further, as a jig for manufacturing the above-mentioned curved ferrite core, it is characterized in that it has heat resistance and the surface on which the ferrite powder compact is placed is formed into a curved shape.

In this case, the jig may have a hemispherical curved surface on which the molded body is installed.

<< Operation >> According to the above configuration, since each ferrite core piece constitutes a part of a curved surface, when these are combined in a mosaic shape, a circumferentially continuous curved ferrite core is obtained.

In addition, the ferrite core piece obtained by this manufacturing method can be easily formed into the curved shape by flexibly deforming the ferrite powder molded into a flat plate along the curved jig by its own weight in the sintering process. To be done.

Further, as the manufacturing jig, one that constitutes a part or all of the curved shape of the product to be obtained may be prepared.

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

FIG. 1 shows the overall structure of a ferrite core according to the present invention.

In the figure, 1 has a hemispherical curved surface, for example,
It is a cooking utensil such as a wok, 2 is a curved ferrite core that is attached to the outer peripheral surface of the appliance 1 and is continuous in the circumferential direction, and the ferrite core 2 is a line segment passing through the center 0 of the appliance 1. A plurality of radially split substantially fan-shaped ferrite core pieces 2a having a predetermined thickness and forming a part of the curved surface of the device 1 are combined along a radial dividing line L and attached to the outer periphery of the device 1. It is a thing.

The manufacturing method of the ferrite core piece 2a is shown in FIG.
As shown in (c).

First, as shown in (a), a ferrite core powder is press-molded into a fan-shaped flat plate shape, which is a curved surface developed shape of the device 1, to obtain a molded body 2 '.

The shape and size of the molded body 2a ′ obtained by the molding at this time are set in consideration of the shrinkage rate due to sintering.

Further, the thickness of the molded body 2a 'is set within 3 to 5 mm, which is a thickness that is likely to be flexibly deformed during sintering.

Next, this molded body 2a 'is subjected to a jig as shown in FIG.
That is, it is installed on the inner surface of the sagger 3, and the whole sagger 3 is loaded into the sintering furnace 4.

The inner surface of the bowl 3 also functions as one kind of molding die formed on the same curved surface as the outer peripheral curved surface of the device 1, and is made of a heat resistant ceramic such as alumina or silica.

The molded body 2a heated to a normal sintering temperature of ~ ° C in the sintering furnace 4 adheres to the inner surface of the sagger 3 by its own weight as shown in (c) as the plasticization occurs by heating. Then, it is deformed along the curved shape of the bowl 3, and the sintering is completed in that state.

The ferrite core pieces 2a obtained as described above are radially attached from the center O of the bottom of the device 1, and adjacent ferrite core pieces 2a are combined along the dividing line L to form a first core. As shown in the figure, the curved ferrite core 2 can be closely integrated with the outer periphery of the device 1.

In the above-mentioned embodiment, the shape of the ferrite core 2 is matched with the outer peripheral shape of the device 1 and is integrally attached thereto, but the ferrite core 2 alone may form one curved solid shape.

In addition, it goes without saying that the curved surface shape of the bowl 3 can be given various shapes in accordance with the curved three-dimensional shape to be obtained.

<< Effects of the Invention >> As described in detail with reference to the embodiments above, in the curved ferrite core according to the present invention, since each ferrite core piece constitutes a part of the curved surface, a state in which these are combined In, it is formed into a curved surface continuous in the circumferential direction.

Therefore, it is particularly suitable for a component having a relatively thin plate thickness, a large size, and an arbitrary curved surface continuous in the circumferential direction, and has a high degree of freedom in design.

Further, the ferrite core piece obtained by this manufacturing method is formed into a final curved surface shape by flexibly deforming the powder molded in a flat plate shape by its own weight along the curved surface jig in the sintering process. Since the product precision is higher than the method of holding the shape that has been press-formed in advance and sintering the shape, in addition, in order to sinter the final product in multiple pieces,
The filter medium is downsized and the firing efficiency is high.

Further, a jig for manufacturing the ferrite core piece may be prepared so as to form a part of the curved surface shape of the product to be obtained, so that it can be adapted to various curved surface shapes.

[Brief description of drawings]

FIG. 1 is a perspective view of an electromagnetic cooker to which the present invention is applied, and FIGS. 2 (a) to 2 (c) are explanatory views showing a sintering process of a ferrite core piece attached to the cooker. 2 ... Curved ferrite core 2a ... Ferrite core piece 2a '... Molded body 3 ... Vase (jig) 4 ... Sintering furnace

Claims (6)

(57) [Claims] 1. A ferrite core piece for a curved ferrite core having an arbitrary outer shape and a predetermined thickness, which is continuous in the circumferential direction. The ferrite core piece comprises a large number of the curved ferrite cores in arbitrary line segments. A curved ferrite core, characterized in that it is divided and the curved ferrite core is formed by combining the ferrite core pieces in a mosaic shape. 2. The curved ferrite core has a hemispherical shape, and the ferrite core piece is formed in a substantially fan shape by a line segment passing through the central axis of the hemisphere. The curved ferrite core according to 1. 3. A ferrite powder compact having an arbitrary outer shape and having a desired thickness is set on the surface of a jig having a desired curved surface, and fired along the curved surface shape of the jig. It is characterized in that a ferrite core piece having a curved shape along the curvature of the jig is formed by being sintered while being flexibly deformed into a curved surface, and a plurality of the ferrite core pieces are combined to form a curved ferrite core. And a method for manufacturing a curved ferrite core. 4. The desired curved surface is hemispherical,
4. The method for manufacturing a curved ferrite core according to claim 3, wherein the molded body is formed of a substantially fan-shaped one obtained by dividing the hemispherical shape into a plurality of line segments passing through the center thereof. 5. A jig for manufacturing a curved ferrite core, which has heat resistance and has a curved surface on which the ferrite powder compact is placed. 6. The jig for manufacturing a curved ferrite core according to claim 5, wherein the installation surface of the molded body is a hemispherical curved surface.