JPH0376008A - Production of magnetic head core - Google Patents

Abstract

PURPOSE:To simultaneously polish many sintered cores so that many heads are simultaneously obtd. by previously providing the 2nd projecting parts having the same length as the length of the projecting parts of magnetic heads in the polishing allowance parts on the same side having the projecting parts and executing compaction molding. CONSTITUTION:The polishing allowance parts 4 on the same side provided with the projecting parts 5 are integrally provided with the 2nd projecting parts 9 projecting to the same length as the length of the above-mentioned projecting parts, by which the sintered core is formed. Magnetic attraction blocks 12 to be inserted and held between both recessed side faces 13 in tight contact therewith are inserted into the spacings formed between the projecting parts 5 and 2nd projecting parts 9 which are in tight contact with each other. The polishing allowance parts 4 of these sintered core groups are polished together with the 2nd projecting block 9, by which the head cores formed with head parts 3 and cavities 2 having prescribed shapes are simultaneously obtd. at one time. The magnetic head cores are obtd. extremely inexpensively in large quantities in this way.

Description

DETAILED DESCRIPTION OF THE INVENTION Object of the Invention [Field of Industrial Application] The present invention relates to a method of manufacturing an erasing magnetic head core used in a video tape recorder or the like.

[Conventional technology]

Conventionally, this type of erasing magnetic head core (hereinafter referred to as head core) generally has a U-shaped portion 1 to which winding is applied, in order to magnetically erase recorded information on a magnetic tape, as shown in FIG. It consists of a left-right asymmetrical head 3 having a gap 2 that applies an erasing magnetic field to the magnetic tape, and a convex portion 5 provided on one side of the U-shaped portion l that serves as a mounting standard for the magnetic head.The manufacturing method thereof is as follows. , in order to obtain the predetermined dimensions of the cavity 2,
A polishing margin 14 (indicated by diagonal lines) is integrally formed on the outer edge of the cavity 2, and the ferrite powder is press-molded into a gap-free shape, and further sintered to form a third
After obtaining the sintered core shown in the figure, both sides were subjected to thickness polishing in a polishing process to obtain a predetermined thickness, and then the polishing margin 14 was finally removed by polishing to form a head core. This polishing allowance 1
In the polishing step 4, the bottom surface 6 of the sintered core is usually attracted onto a surface plate having a magnetic chuck and aligned vertically in a line.
Further, the side surface 7 of another sintered core of the same shape is brought into close contact with the side surface 7 on the opposite side to the convex portion 5, and the sintered cores are arranged in two rows back to back.

After arranging two rows of sintered cores on a surface plate in this way, holding the aligned outer surfaces with magnetic fixing blocks, and tightly fixing the aligned groups of magnetic heads with each other with magnetic chucks, the sintered cores are A head core was obtained by simultaneously polishing two rows of sintered cores to remove the polishing allowances 14 using a grindstone whose outer periphery was formed in eight ways to polish the polishing allowances 14 for two rows.

[Problem to be solved by the invention]

However, with this shape of the sintered core, the number of adjacent rows of sintered cores that can be aligned on the surface plate and ground into a predetermined shape is only two, and it is difficult to arrange many rows of sintered cores adjacently. For example, the protrusions provided on the sintered core get in the way, making it impossible to align all the side surfaces having the protrusions in close contact with each other. Because all the sides do not come into close contact with each other, even if the bottom of the sintered core is attracted by a magnetic chuck on a surface plate and the aligned groups are held down by a magnetic fixed block, the mutual adsorption force of the sides of the sintered core is weak, and the grinding wheel is not attached to the head of the sintered core. If a predetermined polishing is carried out, the alignment of the sintered cores will be destroyed by the external polishing force of the grindstone, and the sintered cores will become fragmented, resulting in defects.

The present invention aims to eliminate such problems and provide a manufacturing method in which sintered cores are arranged in multiple rows of two or more, and these multiple sintered cores are simultaneously polished to obtain a large number of head cores at the same time. It is something.

1. Structure of the Invention [Means for Solving the Problem] The present invention has a shape that is asymmetrical and has a convex portion of a certain length on one side, and is formed by compacting, sintering, and polishing ferrite powder into a predetermined shape. In the manufacturing of finished magnetic head cores,
When compacting the magnetic head core, a second convex portion having the same length as the convex portion of the magnetic head core is provided in advance in the polishing margin on the same side having the convex portion of the magnetic head core, and the second convex portion is powder compacted and sintered. After forming a sintered core, the side surfaces of the convex portion and the second convex portion, as well as the opposing side surfaces where the convex portion is not provided, are arranged in a plurality of rows alternately back to back, and the convex portion and the second convex portion are arranged in plural rows. A magnetic adsorption block is inserted into the gap formed by placing the cores back to back, and a predetermined polishing process is simultaneously performed on the aligned sintered cores to remove the second protrusion and form a magnetic head core with a predetermined shape. A method of manufacturing a magnetic head core is characterized in that:

[Effect]

The convex part that protrudes a certain length on one side of the sintered core and the second convex part that protrudes to the same length as the convex part provided in the polishing allowance on the same side are because their side surfaces are on the same plane. When the convex portions of this and other sintered cores abut against the side surfaces of the second convex portion, the two sintered cores come into close contact with the side surfaces of the convex portion and the second convex portion. Therefore, by arranging the side surfaces of the sintered core in multiple rows alternately back to back and arranging them on the surface plate of the magnetic chuck, and firmly holding and fixing the outside with a magnetic fixing block, the side surfaces of the magnetic head without protrusions, Multiple rows of sintered cores in which the side surfaces of the convex portions and the second convex portions are alternately in close contact with each other form a group of sintered cores that are closely attracted to each other by magnetic force. Furthermore, magnetic adsorption blocks are inserted into both concave sides of the gap between the two protrusions formed by aligning the convex part and the second convex part back to back, and are brought into close contact with the sintered cores aligned on both sides and attracted by magnetic force. If this is done, the mutual adsorption ring between the sintered cores on both sides will further increase, and all the aligned sintered cores will be attracted and fixed to each other by magnetic force, and the alignment will not be disturbed by external force. If the polishing margin of the sintered core group is polished all at once using a whetstone whose outer periphery is formed in accordance with the polishing margin of all rows of this sintered core group, the polishing margin of this sintered core group will become the second polishing margin at the same time. By polishing together with the convex portion, a magnetic head core having a predetermined head and gap can be simultaneously formed. Moreover, even if the second convex part is polished and the mutual adsorption and fixing force of this part is removed, the adsorption and fixing force of the convex part and the magnetic adsorption block remains, and even if grinding is continued until the predetermined shape is reached, the aligned groups will be disturbed. There isn't.

〔Example〕

Embodiments of the present invention will be described in detail below with reference to the drawings.

FIG. 1 is a front view of a sintered core showing an embodiment of the present invention. That is, a U-shaped portion 1 having a flat bottom surface 6 and a flat side surface 7 where winding is applied, an asymmetrical head portion 3 having a gap portion 2 that applies an erasing magnetic field to the magnetic tape, and a flat U-shaped portion 1. In the magnetic head core for erasing, which consists of a convex portion 5 provided on one side facing the side surface 7 and protruding a certain length and serving as a mounting standard for the magnetic head, in order to maintain the predetermined dimension of the gap portion 2, a gap portion is formed. 2 and polish #! A polishing allowance 4 (indicated by diagonal lines) is formed on the outer contour of the head 3 to make the outer shape square, and a convex part is added to the polishing allowance 4 on the same side where the convex part 5 is provided. A sintered core is formed by integrally providing a second convex portion 9 that protrudes by the same length as 5. This sintered core can be formed by integrally forming the ferrite powder compact with a mold, and then a compact with this shape can be obtained, and this compact can be easily sintered in a prescribed manner. You can get it.

FIG. 2 is a front view showing the alignment of the sintered cores in a polishing process for obtaining a head core by polishing the polishing margin 4 of the sintered cores. In order to obtain a head core by polishing from a sintered core having the shape shown in Fig. 1, the bottom surfaces 6 of the sintered core and the bottom 6 of the sintered core are joined and stood upright on a surface plate 10 equipped with a magnetic chuck, and the cores are closely aligned in a row from front to back. On the left side, the side surfaces 7 are placed in close contact with each other in a row as before, and on the right side, the convex side surface 11 with the same length protruding from the convex part 5 and the second convex part 9 are placed back to back. The side surfaces 7 and the convex surfaces 11 are placed in close contact with each other in the same manner, and then the side surfaces 7 and the convex surfaces 11 are placed in close contact with each other alternately.
A large number of rows of sintered cores that can be arranged in a range are arranged. Furthermore, a magnetic adsorption block 12 that is tightly held and held by both concave side surfaces 13 is inserted into the gap formed between the convex portion 5 and the second convex portion 9 that are in close contact with each other. Also, the surface plate 1 formed in this way
A magnetic fixed block (not shown) is also tightly attached to the outside of the multi-row group of 0 sintered cores. When a magnetic force is applied to the magnetic chuck of the surface plate 10 on which the multi-row group of sintered cores formed in this way is mounted on the upper surface, the sintered core groups are extremely firmly attracted to each other and fixed on the surface plate 10. The alignment is not disturbed by external force.

Using a grindstone whose outer periphery is formed in accordance with the grinding line 8 at the boundary between the polishing margins 4 of all the rows of the sintered cores arranged in multiple rows and the head 3 of the magnetic head core, the grindstone is rotated to form the sintered core. If the polishing allowances 4 of the groups are polished simultaneously, the polishing allowances 4 (indicated by diagonal lines) of these sintered core groups will be
The head portion 3 and the cavity portion 2 are polished together with the convex portion 9 to have a predetermined shape.
It is possible to simultaneously obtain the head cores in which the head cores are formed. Moreover, even if the second convex portion 9 is removed by polishing to the polishing line 8, the magnetic adsorption block 12 firmly adsorbs the convex side surface 11 and the concave side surface 13 to each other, fixing the sintered cores to each other, and the alignment is disturbed. Never.

1. Effects of the Invention [Effects of the Invention] As described in detail above, according to the present invention, a head core of a predetermined shape that is polished simultaneously from a large number of sintered cores arranged in multiple rows can be obtained. Therefore, it is possible to provide a method of manufacturing a magnetic head core that can be produced in large quantities at an extremely low cost.

[Brief explanation of drawings]

FIG. 1 is a front view of a sintered core showing one embodiment of the present invention. FIG. 2 is a front view showing the alignment state of the sintered cores in FIG. 1 during the polishing process. FIG. 3 is a front view of a conventional sintered core. DESCRIPTION OF SYMBOLS 1... U-shaped part, 2... Cavity part, 3... Head, 4...
...Grinding allowance, 5...Protrusion, 6...Bottom surface, 7...
Side surface, 8... Polishing line, 9... Second convex portion, 10...
Surface plate, 11...Convex side surface, 12...Magnetic adsorption block, 13...Concave side surface, 14...Grinding margin portion. Figure 7 Figure 2

Claims (1)

[Claims] 1. In manufacturing a magnetic head core that is asymmetrical in shape and has a convex portion of a certain length on one side and is finished into a predetermined shape by compacting, sintering, and polishing ferrite powder, during compaction of the magnetic head core. , a second convex portion having the same length as the convex portion of the magnetic head core is provided in advance in the polishing margin on the same side having the convex portion of the magnetic head core, and the second convex portion is powder-formed and sintered to form a sintered core. , the side surfaces of the convex portion and the second convex portion and the opposite side surfaces without the convex portion are arranged back to back alternately in a plurality of rows, and a gap is formed by back-to-back alignment of the convex portion and the second convex portion. manufacturing a magnetic head core characterized in that a magnetic adsorption block is inserted into the sintered core, and the aligned sintered cores are simultaneously subjected to a predetermined polishing process to remove the second convex portion and form a magnetic head core having a predetermined shape. Method.