JPS62114109A - Manufacture of laminate core for magnetic head - Google Patents

Abstract

PURPOSE:To improve the yield and to reduce the process by welding, a laminated body of a core thin chip on the surface of which an oxide film is formed, cutting it and annealing the result so as to prevent the deterioration in the magnetic characteristic during the working through the adoption of the said process. CONSTITUTION:The surface of a smooth core thin chip 1 formed by a press stage 21 and a grinding stage 22 is subject to oxidation by a surface treating stage 23, the chip 1 is laminated by the core arranging stage and a part is welded in the laminating direction by a laser welding stage 25. Since the oxide film is coated in advance on the chip 1, the chip 1 is not welded in stages other than the welding process. Required number of chips 1 are cut as a core half 2 laminated with required chips 1 at the cut stage 26. Accordingly, the magnetic characteristic is improved by the annealing after welding, no shape change of the chip is caused by the cutting before annealing, it is not required to insert a partition plate between the chips and the process is reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field] The present invention relates to a method for manufacturing a laminate core for a magnetic head.

"Prior art and its problems" As shown in FIG. 5, a magnetic head made of a laminate core is made by laminating a plurality of approximately U-shaped core thin pieces l made of magnetic material (silicon steel plate) to form a core half 2. A pair of core halves 2 are made, and a pair of core halves 2 are abutted against each other to form a magnetic gap 3 at the abutting surfaces, and has been widely used in the past, for example, as a magnetic head for audio.

This core half-filled 2 (laminate core) has conventionally been manufactured by the process shown in FIG. 3. First, a core flake l is produced in a pressing process 11 and a barrel grinding process 12, and then the core flake l is annealed as a single flake in an annealing process 13. Next, in a core alignment step 14, the annealed core flakes l are inserted into a jig and aligned in the same direction and brought into close contact with each other. 4. Insert the partition plate 4 as shown in Figure 4. This partition plate 4 is made of a material 1, such as a copper plate, which is difficult to weld to the core thin piece l in the next laser welding. In the welding step 15, welding is performed in the stacking direction. In Fig. 4, W indicates the welding line. Then, the partition plate 4 part is not welded or the welding force is weak, so the next core separation step 16 is performed.
By a simple separation operation, a predetermined number of core halves 2 are laminated and welded. This core half 2 is then impregnated with a resin liquid in a resin impregnation step 17 to form an insulating resin film between the core thin pieces l.

However, this conventional method for manufacturing a laminate core has the following problems. First, the core flake l is as thin as about 0.1 mm and easily deformed. If this is annealed as a single piece, its hardness will further drop to about 1/3, making it even more easily deformed in the following steps. When deformed, the core flakes 1 may not be aligned or may not be in close contact with each other, resulting in a decrease in yield. Further, annealing is performed for the purpose of improving magnetic properties, but if force is applied or deformation occurs in each step after annealing, the annealing becomes meaningless and the magnetic properties deteriorate. Furthermore, since the work of inserting the partition plate 4 every time a predetermined number of core thin pieces 1 are stacked is complicated, a long lead time is required until the core half body 2 is completed.

``Object of the Invention'' The present invention solves the problems of the conventional laminate core manufacturing method described above, has a high yield, does not cause deterioration of magnetic properties during manufacturing, and shortens the lead time for completion. The purpose is to provide a manufacturing method that can.

"Summary of the Invention" The present invention is based on the analysis that the problems of conventional manufacturing methods are mainly caused by the fact that the core flakes are first annealed as single pieces. The basic structure is annealing, but at the same time other processes have been improved, and it consists of the following steps. That is, the method for manufacturing a laminated core of the present invention includes a surface treatment step of forming an oxide film on the surface of a core flake to be made into a laminated core; a core alignment step of positioning a large number of core flakes in the same direction and bringing them into close contact; and this close contact. A welding process in which a part of a large number of core flakes are welded in the stacking direction to form a core flake block; A cutting process in which a predetermined number of laminate cores are cut out from the welded core flake block; and the cut laminate The present invention is a method for manufacturing a laminate core for a magnetic head, the method comprising the step of annealing the core.

"Embodiments of the Invention" Each step will be described below based on the drawings. FIG. 1 shows the process of the present invention, in which the pressing process 21 and the barrel grinding process 22 are the same as the conventional process. This process forms a smooth core flake l.

In the present invention, this core flake 1 is first subjected to oxidation treatment in a surface treatment step 23, and an oxide film is first formed on its surface. This oxide film prevents the core flakes 1, which will be overlapped and welded in subsequent steps, from welding in areas other than the welded areas. Specifically, this oxidation treatment can be performed by heat treatment in a steam or oxygen atmosphere, for example.

The core flakes l that have undergone this surface treatment step 23 are then processed through a core alignment step 2, which corresponds to the core alignment step 14 in the conventional process.
4, they are oriented in the same direction and stacked. The difference from the conventional core alignment process 14 is that the partition plate 4 is
The point is not to insert it between the two.

The core thin pieces 1 laminated and adhered in this core alignment step 24 are
Next, in a laser welding step 25, a part of the core is welded in the stacking direction to form a core flake block 6 schematically shown in FIG. The core flake block 6 is then cut out as a core half (laminated core) 2 in which a required number of core flakes 1 are laminated in a cutting step 26, and then the core half 2 is annealed in an annealing step 27. In the resin impregnation step 28, an insulating resin layer is formed between the core thin pieces 1 to complete the process.

In the present invention, the reason why it is not necessary to insert a partition plate between the core thin pieces 1 is as follows. In the method of the present invention, the core laminated block 6 is not yet annealed in the cutting step 26. For this reason, the strength of the core flakes l itself is high, and by applying a force P perpendicular to the lamination direction to the core flakes block 6, a core half-hole 2 (laminated core) in which a certain number of core flakes l are laminated can be cut out. I can do it. In addition, in this cutting step 26 or a step before this,
Even if a slight strain occurs in the core half 2, this strain can be removed in the annealing step 27 to improve the magnetic properties. In other words, in the present invention, the annealing step 27
is arranged after the cutting step 26 of the core half body 2, so that the distortion and internal stress generated in the cutting step 26 and the previous step can be removed, and the magnetic properties can be improved.

When an oxide film is first formed on the surface of the core flake l in the surface treatment step 23, as mentioned above, in each of the following steps no welding occurs except for the welded area, and the welded area has the lowest eddy current product. However, if welding occurs in areas other than this welded area, there is no point in reducing the eddy current product by using a laminate core as the magnetic core.

The surface treatment step 23 is an important step for this purpose.

"Effects of the Invention" As described above, in the method of the present invention, annealing, which was conventionally performed on a single core flake, is performed after a certain number of core flakes are stacked and welded, so that magnetic properties can be improved. Furthermore, since the cores are aligned and cut out before annealing to increase the strength of the core flakes, there is no fear that the core flakes will be deformed during these steps, and the yield can therefore be improved. Furthermore, in the core alignment process, there is no need to insert partition plates between the core thin pieces, so the alignment work is greatly simplified and the lead time until completion can be shortened.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing the steps of the method for manufacturing a laminate core for a magnetic head according to the present invention, FIG. 2 is a side view showing the state of cutting in the cutting step, and FIG. 3 is a block diagram showing the steps of the conventional manufacturing method. 4 is a perspective view showing how the partition plate is inserted in the conventional method, and FIGS. 5(a) and 5(b) are block diagrams.
) is a perspective view of a laminate core and a plan view of a magnetic head. DESCRIPTION OF SYMBOLS 1... Core thin piece, 2... Core semi-dead (laminate core), 3... Magnetic gap, 6... Core thin piece block, 21... Pressing process, 22... Barrel grinding process,
23...Surface treatment process, 24...Core alignment process, 2
5... Laser welding process, 26... Cutting process, 27.
... Annealing process, 28... Resin impregnation process. Patent applicant Alps Electric Co., Ltd. Agent Kunio Miura Shigeru Matsui Figure 1 Figure 2 Figure 5

Claims (1)

[Claims] (1) Surface treatment step of forming an oxide film on the surface of the core flakes to be made into a laminated core; Core alignment step of positioning these many core flakes in the same direction and bringing them into close contact; A welding process of welding the parts in the lamination direction to form a core flake block; a cutting process of cutting out a predetermined number of laminate cores from the welded core flake block; and an annealing process of annealing the cut laminate cores. A method of manufacturing a laminate core for a magnetic head, the method comprising: