JP3136645B2 - Method for manufacturing front core of magnetic head - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a front core of a double gap type magnetic head used for erasing information input to a magnetic recording medium.

[0002]

2. Description of the Related Art In recent years, cost reduction activities of this type of magnetic head core have been actively conducted.

A method of manufacturing a front core of a conventional magnetic head will be described below. As shown in FIG. 12, a ferrite center core bar 18 having an I-shaped cross section with a width dimension h is provided with a height n higher than the lower surface of a U-shaped ferrite side core bar 19 having a U-shaped cross section as shown in FIG. Is fitted into a groove 20 having a width dimension i and a height dimension j formed in a staircase shape with the position as a bottom surface. Above the groove 20 of the side core bar 19, a groove 21 having a height k is formed on both sides of the width i of the groove 20 by a dimension k which is wider by a gap width.

[0004] As shown in FIG.
8 formed in the side core bar 19 by fitting
An alkaline glass rod 23 having a predetermined size is inserted into the glass rod 2 for bonding.
3 is melted, and the center core bar 18 and the side core bar 19 are fixed as shown in FIG. Then Figure 1
As shown in FIG. 6, an unnecessary portion is removed by cutting along a line AA 'and a line BB' to obtain a front core having a predetermined size. m
Is the gap width dimension.

[0005]

However, in the above-mentioned conventional manufacturing method, since the fitted center core bar cannot be accurately positioned with respect to the side core bar, a dimensional difference of the gap occurs, and the head such as impedance or erasing characteristics is generated. There is a problem that the characteristics are varied, a problem occurs in that the center core bar is inclined with respect to the side core bar, so that a defect occurs in the bobbin insertion in a later process, and a material loss occurs because unnecessary portions are cut. There is a problem that it takes place and takes a lot of man-hours.

SUMMARY OF THE INVENTION The present invention solves the above-mentioned conventional problems, and has a high precision in the gap dimension, no variation in head characteristics, a good yield in the post-process such as bobbin insertion, and a low-cost front of a magnetic head. An object of the present invention is to provide a method for manufacturing a core.

[0007]

In order to achieve this object, a plurality of first grooves are provided on a first surface of a rectangular parallelepiped block made of ferrite, and the width is smaller than the first grooves .
In addition, a first slit is provided at the bottom of the first groove toward the second surface opposite to the first surface, and the first groove and the first groove are provided .
The molten first glass is poured into the lit and solidified, and a pair of second grooves are formed from the second surface toward the first surface to a depth that connects with the first slit . By providing a portion corresponding to the center core bar between the two grooves, and forming a pair of third grooves that are deeper than the second grooves so as to sandwich the pair of second grooves, A portion corresponding to the side core bar is provided between one of the pair of third grooves adjacent to one of the second grooves and one of the second grooves, and the first groove is provided in the pair of second grooves. After pouring and hardening a second glass having a lower melting point than that of the first glass ,
The rectangular parallelepiped block was cut so as to cross the middle of the lit and the middle of the third groove to be divided into individual pieces.

[0008]

According to this method, the center core bar and the side core bar are integrally and simultaneously processed to form a pair of gaps with high dimensional accuracy.

[0009]

An embodiment of the present invention will be described below with reference to the drawings.

As shown in FIG. 2, a double-gap type magnetic head comprises a bobbin 15 having a predetermined number of turns wound with a coil wire 14 inserted into a ferrite back core 16 and a ferrite front core 13. Back core 16
The magnetic circuit unit is constructed by holding and fixing the magnetic circuit unit in a plastic outer frame 17. Less than,
A method of manufacturing the ferrite front core 13 of the magnetic head will be described with reference to FIGS. 1 and 3 to 11.

As shown in FIGS. 3 and 4, on one surface of a block 1 of a rectangular parallelepiped made of ferrite, a distance a between centers of the slits 2 and a slit 2 having a predetermined size b corresponding to a gap width and a glass rod are provided. A plurality of grooves 3 for forming a pool after fusion are formed at the interval c by simultaneously processing a plurality of grooves in an integrated structure. Next, as shown in FIGS. 5 and 6, the glass rod 4 is inserted into the groove 3 and heated at a temperature of about 700 ° C. to melt the glass rod 4, so that the molten glass penetrates the slit 2 and is fused. At the same time, a glass pool 5 is formed. Next, as shown in FIG. 7, a groove 8 for forming a center core bar 6 and a side core bar 7 in a predetermined shape on a surface opposite to the surface on which the slit 2 and the groove 3 of the block 1 are formed, and an adjacent front surface. Grooves 9 for dividing the side core bar 7 adjacent to the core bar
As in the case of the slits 2 and the grooves 3, and are formed by simultaneously processing a plurality of them in an integrated structure. Note that the depth of the groove 8 is set to such a degree that a part of the slit 2 formed from the opposite surface is cut off, and the depth of the groove 9 is located at the level of the boundary line between the slit 2 and the groove 3. About depth. Further, a width dimension f obtained by adding a width dimension e of the front core bar to a width dimension d of the groove 9 coincides with the interval c of the groove 3, so that the slit 2 is positioned at the center of the width dimension e of the front core bar. Is formed.

After forming the grooves 8 and 9 as described above, FIG.
As shown in FIG. 9, a glass rod 10 having a lower melting point than the molten glass of the glass pool 5 is inserted into the groove 8, and approximately 600
The glass bar 10 is melted by heating at a temperature of ° C. to form a glass pool 11. Then, as shown in FIG. 10, the front core bar is cut along the line CC ′ so that the depth dimension of the slit 2 becomes a predetermined dimension g, and unnecessary portions are removed.
As shown in FIG. 1, a front core 12 having a width dimension e is completed with a slit 2 having a width dimension b at a distance a between slit centers.

As shown in FIG. 1, the cut surface of the front core may be processed into an arc shape to form a front core 13 having an arc surface of the final shape of the magnetic head.

As described above, according to the present embodiment, a slit having the same size as the gap width is formed, the slit is filled with molten glass and fused, and the groove enters the slit by groove processing of the opposing surface. And the slit width can be stably maintained until the front core is completed. Therefore, the gap width is determined only by the size of the first slit, and there is no cause of dimensional defects. Therefore, two gap widths can be formed with high accuracy, and variations in head characteristics such as impedance or erase characteristics can be reduced. Also,
Since the center core bar and the side core bar are simultaneously processed and a plurality of the center core bar and the side core bar are simultaneously processed in an integrated structure, it is possible to eliminate defects such as displacement and inclination of the center core bar and the side core bar. Further, since the use efficiency of the material is improved, the material loss is reduced, and since a plurality of materials are processed at the same time, the number of steps can be greatly reduced and the cost can be reduced.

[0015]

As described above, according to the present invention, a plurality of first grooves are provided on the first surface of a rectangular parallelepiped block made of ferrite, and the width of the first grooves is smaller than that of the first grooves . At the bottom, a first slot toward the second surface opposite to the first surface
The Tsu bets provided, allowed to set by pouring the first glass melted in the first groove and the first slit, the first from the second surface 1
A pair of second grooves are formed to a depth that connects to the first slit toward the surface of the pair of grooves, and a portion corresponding to the center core bar is provided between the pair of second grooves, and a pair of second grooves is formed. Is formed and a pair of third grooves deeper than the second groove are formed, so that one of the pair of second grooves and a pair of third grooves adjacent to one of the second grooves are formed. A portion corresponding to the side core bar is provided between one of the grooves, and a pair of second
After pouring and hardening the second glass having a lower melting point than the first glass into the groove, the rectangular parallelepiped block is cut so as to cross the middle of the first slit and the middle of the third groove. By dividing into individual pieces, it is possible to realize an excellent method of manufacturing a front core of a magnetic head which can increase the accuracy of the gap dimension, improve the yield of the subsequent process without variation in head characteristics, and reduce the cost. Things.

[Brief description of the drawings]

FIG. 1 is a perspective view of a front core of a magnetic head core according to an embodiment of the present invention.

FIG. 2 is a perspective view of a main part in which a part of a double gap type magnetic head using the front core is omitted.

FIG. 3 is a perspective view of a block of the front core.

FIG. 4 is a perspective view showing a state in which a slit and a groove are machined in the block of FIG. 3;

FIG. 5 is a perspective view showing a state where a glass rod is inserted into the groove of FIG. 4;

FIG. 6 is a perspective view showing a state in which the glass rod of FIG. 5 is melted.

FIG. 7 is a perspective view showing a front core bar in which a groove for forming a center core bar and a side core bar and a groove for dividing into individual pieces are formed in the block of FIG. 6;

FIG. 8 is a perspective view showing a state where a glass rod is inserted into the groove of FIG. 7;

9 is a perspective view showing a state in which the glass rod of FIG. 8 is melted.

FIG. 10 is a perspective view showing a cutting line for removing unnecessary portions in FIG. 9;

FIG. 11 is a perspective view of a front core formed by cutting the front core bar of FIG. 9;

FIG. 12 is a perspective view of a center core bar of a conventional magnetic head.

FIG. 13 is a perspective view of the side core bar.

FIG. 14 is a perspective view showing a state in which a side core bar is fitted to the center core bar and a glass rod is inserted into a formed groove;

FIG. 15 is a perspective view showing a state in which the glass rod of FIG. 14 is melted.

16 is a front view of FIG.

[Explanation of symbols]

 2 Slit 6 Center core bar 7 Side core bar 11 Glass pool 13 Front core

Claims (1)

(57) [Claims] A plurality of first grooves provided on a first surface of a rectangular parallelepiped block made of ferrite, the width of the first grooves being smaller than that of the first grooves , and the first grooves being provided at the bottom of the first grooves ; Providing a first slit toward a second surface opposite to the surface,
The first groove melted in the first groove and the first slit;
A pair of second grooves are formed from the second surface toward the first surface to a depth that connects with the first slit, and the pair of second grooves is formed. A part corresponding to the center core bar is provided between
By forming a pair of third grooves deeper than the second groove so as to sandwich the pair of second grooves, one of the pair of second grooves and the second A portion corresponding to a side core bar is provided between one groove of the pair of third grooves adjacent to the first groove, and a second glass having a lower melting point than the first glass is provided in the pair of second grooves. After pouring and solidifying the glass, the rectangular parallelepiped block is cut so as to cross the middle of the first slit and the middle of the third groove, thereby dividing the rectangular block into individual pieces. Manufacturing method of front core.