JPS61237404A - Manufacture of amorphous cut core - Google Patents

Abstract

PURPOSE:To form a highly efficient amorphous cut core with little iron loss, by whetting mechanically the cut face of a cut core after it is etched chemically. CONSTITUTION:An oval wound core is formed by winding a thin belt of an amorphous magnetic material. After this wound core is annealed and cut by conventional methods, the cut face thereof is etched chemically. The cut face etched chemically is whetted mechanically in a subsequent whetting process, so as to form an amorphous cut core. By whetting the cut face mechanically after it is etched chemically, in this way, iron loss is reduced sharply, the deterioration of a magnetic characteristic due to cutting is lessened, and thus a highly efficient amorphous cut core is obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field] The present invention relates to a method for manufacturing an amorphous cut core used in a transformer with low iron loss and high efficiency.

[Background Technology J Generally, cut cores used in transformers with low iron loss and high efficiency are made of grain-oriented silicon steel sheets for large equipment, and non-oriented electrical steel sheets are used for small equipment. The method for manufacturing the cut core is shown in FIG. That is, a coiled core is formed by winding a copper strip of a certain width into a Troigle shape or an oval shape, and this coiled core is fixed with a fixing strip, a fixing mold, or a resin mold, and then cut and divided into two parts. A cut core is formed by this process, and the cut surface of the cut core thus formed is subjected to mechanical polishing or chemical etching to remove burrs and smoothen the surface.

Note that annealing is performed as necessary to remove distortion from the winding F. FIG. 2 is a characteristic diagram showing the relationship between the manufacturing process of the cutoff 7 and the iron loss increase rate, which is shown at point #aC or D in the above conventional method. That is,
The cut core in the characteristic diagram is a unidirectional silicon steel plate (Orient Core Zlo thickness 0.311II) as a copper strip.
The graph shows the change in iron loss when a 200 VA transformer is formed using 1), and the iron loss value after fixing and cutting the wound core increases significantly compared to the iron loss value immediately after annealing ( approximately 150%). In this case, the wound core is fixed by binding each leg of the oval shaped wound core with non-magnetic tape (1) and then molding it with resin. Compressive stress is applied to a positively magnetic silicon steel plate, reducing low frequency iron loss by 2.
The magnetic properties are degraded by an increase of about 5%. *Ta,
The cutting of the winding core causes unevenness on the cut surface, and also causes the generation of flash and rare sheet, which increases the leakage magnetic flux due to the air gap caused by the unevenness.
Due to the increase in eddy current loss due to the rear shot, the iron loss further increases by about 25%. In order to reduce the increase in iron loss and leakage magnetic flux caused by fixing and cutting, the cut surface is polished or etched. #ID indicates the case where the cut surface was chemically etched, and in any case, when the cut surface was rejoined and the iron loss was measured, the iron loss almost recovered to the value after annealing. I understand that. In addition, if you want completeness,
By performing chemical etching after polishing the cut surface, the increase in iron loss due to fixing and cutting can be more reliably reduced. In conventional examples, chemical etching is performed either alone or as a post-polishing process.

By the way, iron-based amorphous magnetic materials (for example, Fe@6B2o, FeysBtoSitz, etc.) have better magnetic properties than conventional magnetic materials (7-elite, silicon steel sheets, etc.).
A thin strip (thickness 10 μ-
~50 μm) to form an amorphous cut core, the iron fan amorphous magnetic material has less high-frequency iron loss, higher saturation magnetic flux density, and better squareness than 7-elite. In addition, while it has characteristics such as lower iron loss and lower excitation power (VA) than silicon steel sheets,
It has processing problems such as high magnetostriction and being thin and hard. The solid line B in Figure 2 shows the change in iron loss when an amorphous cut core is formed using a ribbon of iron-based amorphous magnetic material. It can be seen that the loss has increased significantly (approximately 300%). Here, the method for fixing the amorphous karate core described above uses a resin mold that is optimal as a method for fixing a small transformer (optimal conditions are disclosed in JP-A-59-4109), and the fixing process is The increase in iron loss is 50
It is about %. On the other hand, in the cutting process, iron loss increases due to the same reasons as in the conventional example, but iron-based amorphous magnetic materials have larger magnetostriction than silicon steel sheets, and the iron core space factor (space 77 Since the ribbon is thin and brittle, the increase in iron loss is 200%.Therefore, it may be possible to improve the magnetic properties by polishing the cut surface as in the conventional example. , as shown by the solid line B in Figure 2, the iron loss is hardly reduced, and the same is true when chemical etching is performed instead of polishing. Therefore, there was a problem that an amorphous cut core with low core loss and high efficiency could not be obtained.

[Objective of the Invention J The present invention has been made in view of the above points, and its object is to provide a highly efficient method for manufacturing an amorphous cut core with low iron loss.

[Disclosure of the Invention 1 Fig. 1 shows the manufacturing process of the method of the present invention. First, a thin film made of an iron fan amorphous magnetic material is wound and then annealed to form a wound core. Next, This wound core is fixed in a resin mold and then cut to form a cut core, and the cut surface of the cut core is chemically etched and then mechanically polished, resulting in low iron loss (high efficiency). Amorphous cut cores can be obtained.

(Example) Fet, B+iS is (Me
Using a thin strip (width: 1011 x thickness: 30 μm) of Lglas 2605-S3, wind this thin strip to create an oval-shaped wound core (magnetic path cross-sectional area: 851 II, 112 mm, magnetic path length: 11,411 mm).
11% (weight: 50 g) were formed into two pieces. After this wound core is annealed and cut in the usual manner, the cut surface is chemically etched as follows. That is, chemical etching first performs alkaline degreasing, and then etches with a nitric acid/hydrogen peroxide aqueous solution (35°C) (20 minutes in 6 minutes).
μ-), followed by washing with water and drying. The chemically etched cut surface was mechanically polished in the next polishing step to form an amorphous cut core. The table below shows the iron loss in each process of the prototype cut cores S3 and S2.The iron loss was measured at 20K.
Hz, 3 K Gauss, and the results are shown by solid line A in FIG.

As is clear from the above measurement results, by chemically etching the cut surface and then mechanically polishing it, the core loss is significantly reduced and the deterioration of magnetic properties due to cutting is reduced, resulting in a highly efficient amorphous material. Now you can get cut core. Possible reasons for this result are as follows.

In other words, the thickness of the thin strip of iron fan amorphous magnetic material obtained by ultra-quenching the molten alloy on a roll rotating at high speed is small, and the amount of etching caused by chemical etching is about the same as the thickness of the thin strip. Therefore, due to chemical etching, the cut surfaces of each thin layer become rounded, and there are almost no vertical surfaces. Note that since the thickness of the silicon steel plate is much larger than the amount of etching by chemical etching, the corners of the cut surface are rounded and the burr is removed, but the vertical plane at the center of the cut surface is maintained.

In addition, the thickness of the thin strip is extremely variable, compared to 95 to 98% when using silicon steel plates for Space 7 actors.
The ratio is 60 to 80%, and there are many air gaps on the cut surface, which increases magnetic resistance during bonding and increases leakage magnetic flux. When the cut surface in such a state is mechanically polished, the vertical surface of each rounded cut surface gradually increases from the center toward both end corners, and the space 7 actor of the cut surface becomes different from before cutting. The state is restored to the same state and the magnetic properties are improved.

On the other hand, the following reasons can be considered as the reason why the iron loss is not reduced even if the cut surface is mechanically polished as in the conventional example.

When cutting an 8-core core with a GC blade (green carborundum blade) or a diamond blade that rotates at high speed, the cut surface will be completely short-circuited due to the occurrence of cracks on the cut surface.To remove this condition. However, the iron-based amorphous magnetic material after annealing is extremely brittle and cannot withstand mechanical shock, so we molded the outer periphery of the wound core with resin. However, it was difficult to remove the rarity (s-) due to paris on the cut surface and obtain flatness by mechanical polishing as in the conventional example. Note that by impregnating U (glue) between each ribbon, mechanical rigidity that can withstand intense polishing can be obtained, but the hardening shrinkage stress of TJ4 lubricant causes deterioration of magnetic properties, especially high-frequency iron loss. cannot be implemented because it would result in a significant increase in

[Effect of the invention 1 Wood climbing nl 1 Shito; Kimegami et al.
After fixing, the cut core is cut to form a cut core, and the cut surface of the cut core is chemically etched and then mechanically polished to obtain an amorphous cut core with low iron loss and high efficiency. It has the effect of being able to

[Brief explanation of drawings]

Fig. 1 is a diagram showing the manufacturing process of an amorphous core by the method of the present invention, Fig. 2 is a characteristic diagram showing changes in iron loss in each step of the cut core in the method of the present invention and the conventional method, and Fig. 3 is a diagram showing the conventional method. It is a figure showing the manufacturing process of the cut core by. Agent Patent Attorney Ishi 1) Chief Seven Swordsman'? 8 pages← 〆Figure 3 Yuzega

Claims (1)

[Claims] (1) A thin ribbon made of an amorphous magnetic material was wound to form a wound core, this wound core was fixed and then cut to form a cut core, and the cut surface of the cut core was chemically etched. A method for producing an amorphous cut core, characterized in that it is then mechanically polished.