JPS6178111A - Manufacture of magnetic core - Google Patents

Abstract

PURPOSE:To obtain the magnetic core having low degree of deterioration to accompany with the work performed by a method wherein the cut face o the magnetic core is polished while the cut face is being sucked by a vacuum pump when a cutting work is performed on the magnetic core. CONSTITUTION:A number of small holes are provided on a polishing paper 2, and the lower surface of the polishing paper is supported by the vessel 4 which is decompressed by a vacuum pump 3. Therefore, when a polishing work is performed by contacting the magnetic core 1 to the polishing paper 2, the burrs and broken pieces generating when the polishing work is performed are absorbed toward the lower part of the vessel 4 as shown by the arrows in the diagram. As a result, the cut surface having no foreign matters between the burrs and the layer can be obtained, and the magnetic characteristics (iron loss value) can be recovered to the condition before cutting.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field] The present invention relates to a method for manufacturing a low-loss cut core (mainly an amorphous cut core) for a transformer.

[Background technology]

Amorphous magnetic ribbon has a higher Curie temperature TC and saturation magnetic flux density Bs than the conventionally used soft material ferrite (and has a higher electrical resistance than silicon steel sheets and permalloy). is attracting attention as a new soft magnetic material.

Generally speaking, the method for producing a magnetic core using an amorphous magnetic ribbon is to wind the ribbon to form an iron core (magnetic core).
However, in this case, the magnetic core is cut in consideration of the cost of the winding wire and the use of the gapped transformer.

Amorphous magnetic ribbons are manufactured industrially using a single roll method, so the surface of the ribbon is uneven.
For this reason, voids are created between the laminated layers. Amorphous ribbon is extremely pliable when unheated, but becomes brittle when heat treated to improve magnetic properties after winding.

Therefore, if the magnetic core is cut with voids still present after heat treatment, cracks or cracks may occur at the cut portion, or fragments of the magnetic ribbon may enter the glabella, deteriorating the magnetic properties and increasing iron loss. Was. Therefore, if the interlayer gap is impregnated with an adhesive resin or the like and then cut, and the cut surface is polished, it is possible to prevent the deterioration of the magnetic properties due to the cutting process. However, this method is effective in the case of Co5 amorphous, which has a very small magnetostriction constant, but in the case of Fe-based amorphous, which has a large magnetostriction constant, internal stress is generated due to curing shrinkage of the interlayer adhesive resin, and the magnetic properties was deteriorating. In order to avoid cutting the laminated state, a so-called laminated magnetic core is being considered, which is produced by laminating and heat-treating amorphous ribbons that have been punched into the desired shape in advance.
Amorphous ribbons are extremely hard and difficult to punch, and there are many practical problems such as poor material yield.

[Purpose of the invention]

In view of the above circumstances, it is an object of the present invention to provide a method by which a magnetic core with little processing deterioration can be obtained when manufacturing a magnetic core having a gap. Although this invention is mainly effective for Fe-based amorphous Iin cores, it is also applicable to cutting wound cores made of other magnetic ribbons.

[Disclosure of the invention]

In order to achieve the above object, the present invention provides the following advantages: When cutting a magnetic core made by laminating or winding magnetic ribbons,
The gist is a method for manufacturing a magnetic core that is characterized by polishing the cut surface of the magnetic core while suctioning it to avoid foreign matter from entering between the eyebrows.

By winding an amorphous magnetic ribbon to create a magnetic core and subjecting it to appropriate heat treatment, distortions during amorphous manufacturing and winding can be removed, and for high frequency use, a fine crystalline phase can be precipitated to create a low-iron core. Magnetic properties with excellent loss can be obtained.

In order to cut this magnetic core, it is necessary to fix the magnetic core with a resin mold, etc. However, in a magnetic core using a magnetic ribbon with a large magnetostriction constant such as FeI2 amorphous, resin is impregnated between the eyebrows of the ribbon. Then, iron loss increases due to stress due to hardening shrinkage, etc. However, even if it is Fe-based amorphous, if it is molded without resin between the eyebrows, the iron loss will not increase significantly. When the magnetic core obtained in this way is cut with a rotating blade such as a micro cutter, if there is no resin between the eyebrows, cracks may occur between the layers of the cut section, and fragments of the magnetic ribbon may enter the eyebrows, resulting in iron loss. increase Furthermore, if the cut surface of this magnetic core is polished with emery paper, etc., the iron loss value will decrease slightly and the magnetic properties will be restored to a certain extent, but as a result of polishing, foreign matter such as fragments of magnetic ribbons will enter between the eyebrows, and the It does not improve the magnetic properties.

Specifically, for example, if the cut surface is polished using a device such as that shown in FIG. 1, it is possible to remove the foreign matter from the edges and between the eyebrows and improve the magnetic properties.

In FIG. 1, abrasive paper 2 has many fine holes, and the lower surface of this abrasive paper 2 is received in a container 4 whose pressure is reduced by a vacuum pump 3, and suction is applied thereto. Therefore, if the magnetic core 1 is applied to the abrasive paper 2 of this polishing device for polishing, the particles and debris generated during polishing will be sucked downward in the container 4, as shown by the arrow, A cut surface with no foreign matter between the eyebrows can be obtained, and magnetic properties (
Iron loss value) almost recovers to the state before cutting.

The method of suction may be other than the above.

There are no particular restrictions on the manufacturing method or heat treatment of the magnetic core.

[Example 1] An amorphous ribbon of alloy composition F8t* Bl&Sis was wound to form @magnetic core (iron core) 1' as shown in Fig. 2.
was created. The thin strip has a width of Loam and a thickness of 25 to 30 μm.
The inner diameter of the magnetic core is 7 mm for the short axis, 25 a+m for the long axis, and the laminated thickness is 3 mm. After heat-treating this wound magnetic core 1' at 450° C. for 60 minutes, it is placed in an aluminum case 5 as shown in FIG. 3, and molded with room temperature curing epoxy adhesive 6 as shown in FIG. Fixed. In the figure, 5' is the center of the case. At this time, the resin was not applied between the eyebrows. This molded product is cut together with the case using a grindstone blade as shown in Fig. 5, and further,
The cut surface 7 was polished using the polishing apparatus shown in FIG. 1 to obtain the final magnetic core 1.

[Comparative Example 1a] The same amorphous ribbon as in Example 1 was wound to produce a wound core of the same shape, and heat treated under the same conditions. This was resin molded and cut under the same conditions, and the cut surface was polished using conventional wet polishing to obtain the final centering.

[Comparative Example 1b] Example 1. The same amorphous ribbon as in Comparative Example 1a was wound to produce a wound core of the same shape, and heat treated under the same conditions.

This was fixed using the same resin by impregnating the resin between the layers. Furthermore, it was cut in the same manner and polished in the same manner as in Comparative Example 1a to obtain the final magnetic core.

[Example 2, Comparative Examples 2a, 2b] Alloy composition F es+ B13. SS ji,s Ct
O) 7Mo) Using the Lt fas ribbon (the shape of the ribbon is the same as in Example 1), use the same method as in Example 1 and Comparative Examples 1a and lb.
We created different types of magnetic cores and compared them. However, the heat treatment conditions in this case are 385° C. and 2 hours.

(Example 3, Comparative Examples 3a, 3b) Alloy composition F8? Example 1 with B11 Sig amorphous ribbon (the shape of the ribbon is the same as Example 1), Comparison f
Three types of magnetic cores were made using the same method as f1la and 1b,
compared. However, the heat treatment conditions in this case are 400t
, 2 hours.

As shown in Table 0, which summarizes the measurement results of iron loss values for the above three examples and comparative examples, all of the examples obtained better characteristics than the comparative examples. .

(The following is a blank space) [Effects of the invention] This invention is as described above, and according to this,
Even with an amorphous material such as Fe-based material having large magnetostriction, it is possible to obtain a magnetic core having a bonded surface and excellent magnetic properties (low iron loss).

[Brief explanation of the drawing]

FIG. 1 is a simplified explanatory diagram showing a polishing apparatus convenient for carrying out the present invention, and FIGS. 2 to 5 are process explanatory diagrams of an embodiment of the present invention.

Claims (2)

[Claims] (1) A method for manufacturing a magnetic core, which is characterized in that when cutting a magnetic core made by laminating or winding magnetic ribbons, the cut surface of the core is polished while being sucked to prevent foreign matter from entering between the layers. (2) The method for manufacturing a magnetic core according to claim 1, wherein the abrasive paper is provided with many fine holes, and the surface opposite to the surface that the magnetic core contacts is vacuum-sucked.