JPH03137806A - Production of magnetic head - Google Patents

Abstract

PURPOSE:To exactly position glass rods with grooves by forming the grooves on head blocks, then installing the glass rods into the grooves, thereby packing glass into the grooves. CONSTITUTION:Track grooves 73 are formed by track working on a surface 72 having the curved shape of the front surface of the head core block 71 and a gap 74 is provided. A pair of the grooves 75 are formed toward the longitudinal direction on the front surface 72 of the block 71. A pair of the grooves 75 are provided apart a prescribed spacing on both sides of the gap 74. The grooves 75 are formed at the size at which the glass rods 76 for packing glass can be freely fitted and removed into and from the grooves. The depth of the grooves 75 is so determined as not to arrive at a finally finished shape line 77 to prevent the leaving of the grooves 75 on the finished surface at the time of final finishing. The grooves 75 for glass installation are directly worked to the block 71 in place of jigs for installing the glass rods in such a manner, by which the glass packing into the grooves 73 is executed even if the jigs are not used. The cost is reduced and the glass rods 76 are exactly positioned with respect to the block 71.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method of manufacturing a magnetic head used in information recording and reproducing devices such as video tape recorders (VTRs) and digital audio tape recorders (DATs).

[Conventional technology]

The magnetic tape used in conventional consumer VTRs generally uses an iron oxide recording medium,
2. Description of the Related Art Magnetic recording devices having high recording density, such as mVTRs and DATs, have been improved in quality by using metal-based recording media with high coercive force.

In order to bring out the full characteristics of a magnetic tape, it is generally said that the saturation magnetic flux density (hereinafter referred to as BS) of the head material needs to be five times or more the coercive force (hereinafter referred to as H6) of the tape. Ha of iron oxide is about 600 (Oe), and in the case of metal tape it is about 1400 (Oe).

In contrast, the BS of oxide magnetic material (ferrite), which is the magnetic head material used in consumer VTRs, is approximately 50.
Since it is 00G, it is more than 5 times and sufficient for iron oxide tape, but it is less than 5 times for metal tape, so 1400X5 is necessary to bring out its characteristics.
= 7000, and Bs of 7000G or more is required. Therefore, metal magnetic materials with high B3 (such as Sendust) have come to be used as magnetic head materials.

Conventionally, as a magnetic head using this type of sendust, a structure shown in FIGS. 6(a) and 6(b) is known. The magnetic head shown in the figure is called a "bulk type head", and before the head core halves 1a and lb are bonded together to form a gap, a track width regulating groove is formed, and then the track width is The regulating groove is filled with glass 2.

However, in order to manufacture this bulk type head, tracks are processed on the core halves 1a and lb before the gap is formed, so a high precision technique is required when welding the core halves 1a and lb together. I have to do track matching.

Therefore, a magnetic head has been proposed that can omit the track alignment process that is necessary in the conventional bulk type head (see FIGS. 7(a) and 7(b)). This magnetic head is called an all-track head (hereinafter referred to as an AT head) because its entire width is a track, and as shown in Figures 7(a) and (b), the AT head , a pair of helad core halves 10a and 10b are welded to each other,
A track width regulating groove 12 forming the track 11 is filled with glass 13, and this glass 13 is exposed on the tape sliding surface.

When manufacturing this AT head, first, a pair of rod-shaped head core blocks are welded together using silver solder or the like to form a gap, thereby forming a head core block. Next, track processing (AT pre-processing step) to form track grooves in this head core block, glass filling processing step to fill the track grooves with glass, R-shape ( R polishing process to form a curved surface shape (such as a circular arc shape), a sliding surface processing process to process the R polished tape sliding surface, and after this sliding surface processing,
Processing is performed in the order of the slicing process of slicing in a direction parallel to the track groove to form a heel tip.

[Problem to be solved by the invention]

In the manufacturing process of the magnetic head as described above, particularly in the glass filling processing process, glass filling has conventionally been performed using a glass filling jig 51 made of graphite or the like, as shown in FIGS. 8 to 11. That is, a plurality of notch grooves 55 are formed at a predetermined pitch in a pair of parallel side plate parts 53 and 54 that stand up from both side edges of the bottom part 52, and the grooves 5 of the side plate part 53 are
5 and the groove 55 of the side plate part 54, a glass rod 56 is installed in a hanging manner. On the upper surface of the bottom part 52, a head core block 57 for manufacturing AT heads is placed at a glass filling temperature (approximately 7
The head core blocks 57 are arranged directly below each glass rod 56 and facing in the same direction as the glass rods 56. Moreover, the glass rod 56 has a track groove 58.
The head core block is disposed in contact with the upper surface 59 of the head core block on which the head core block is formed. In this way, the glass filling jig 51 with the glass rods 56 disposed on the upper surface 59 of the head core block 57 is stored in a heating furnace and heated at a high temperature to melt the glass rods 56 and fill them in the track grooves 58. It was filled with glass.

However, with such conventional glass filling methods,
As shown in FIG. 12, the notch 4 of the glass filling jig 51
The glass 60 may be fused to the glass 55, etc., and therefore it is necessary to periodically perform cleaning to remove the fused glass 60, or to replace the glass filling jig 51 with a new one, which increases cost and man-hours. There was the issue of bulk.

The present invention has been made to solve this problem, and an object of the present invention is to provide a method for manufacturing a magnetic head in which a glass rod can be installed in the glass filling process without using a glass filling jig.

[Means to solve the problem]

A method for manufacturing a magnetic head according to the present invention includes a step of filling track grooves of a head core block with glass, after forming a groove in the head core block, a glass rod is installed in the groove. Then, the track grooves are filled with glass.

[Function] In the present invention, the glass rod is positioned by the groove formed in the head core block, and therefore the glass rod can be installed in the head core block without using a glass filling jig.

〔Example〕

The present invention is based on the premise that it is used in a manufacturing process using a rod-shaped head core block 57 (for example, made of a ferromagnetic metal material) for an AT head. As shown in FIG. 3, the head core block 57 is subjected to various processes including track processing C1 glass filling d, R polishing e1 sliding surface processing f, and slicing processing g, and finally as shown in FIG. 7(a). , a head chip 41 as shown in (b) is manufactured.

1 and 2 are diagrams showing an embodiment of the present invention, in which a surface 7 of the upper surface of a head core block 71 having a curved shape is shown.
2, a track groove 73 is formed by track machining, and numeral 74 indicates a gap. A pair of grooves 75 are formed in the upper surface 72 of the head core block 71 in the longitudinal direction, and the pair of grooves 75 are provided on both sides of the gap 74 at a predetermined interval.

This valley groove 75 has a size that allows a glass rod 76 for glass filling to be inserted and removed freely, and the depth of this groove 75 is set to the final finished shape line 7, as shown in FIG.
7, and groove 75 during final finishing.
This prevents any residue from remaining on the finished surface.

Therefore, when performing glass filling processing on the head core block 71 in which the grooves 75 are pre-formed on the upper surface 72 as described above, the head core block 71 is bonded to a predetermined mounting base with an inorganic adhesive or the like, and the grooves 75 are After inserting and installing the glass rods 76 into each of the head core blocks 75, the head core block 71 and the glass rods 76 are heated to approximately 700° C., whereby the glass rods 76 are melted and the track grooves 73 are filled with glass. In this way, in the method of this embodiment, the grooves 75 for glass installation are directly machined in the head core block 71 instead of the jig for installing glass rods, so the track grooves 73 can be filled with glass without using a jig. This enables cost reduction and accurate positioning of the glass rod 76 relative to the head core block 71.

In addition, the head core block 71 is removed in the process after glass filling.
1: If R polishing and sliding surface machining are carried out and final polishing is performed to the final finished shape line 77, this line 7
The grooves 75 formed above 7 are completely removed, and no grooves 75 remain on the surface of the head chip 41.

4 and 5 are diagrams showing another embodiment of the present invention. In this embodiment, one a85 is formed in the gap portion of the head core block 81. FIG. Similarly to the above embodiment, track grooves 83 are also formed on the upper surface 82 of this head core block 81. Further, like the groove 75 described above, the groove 85 does not reach the final finished shape line 87. Therefore, in this embodiment, since the glass rod 86 can be placed at the center of the head core block 81, the track groove 83 can be filled with glass by arranging one glass rod 86.

Incidentally, the present invention can also be used for manufacturing the bulk type head shown in FIGS. 6(a) and 6(b).

Note that the same numbers in the same numbers indicate the same or equivalent parts.

〔Effect of the invention〕

As explained above, the present invention performs glass filling by installing a glass rod in a groove formed in a head core block, so that the glass rod is positioned by the groove, eliminating the need for a glass filling jig. Glass rods can also be installed.

[Brief explanation of the drawing]

Figures 1 to 3 are diagrams showing one embodiment of the present invention.
Figure 2 is a perspective view of the head core block, Figure 2 is a sectional view of the head core block, Figure 3 is a perspective view showing the state in which the head core block is processed, and Figure 4 shows another embodiment of the present invention. 1 is a perspective view of the head core block, FIG. 5 is a sectional view corresponding to FIG. 2, and FIGS. 6(a) and (b).
) are a plan view and a front view of the bulk type head, and FIG. 7(a). (b) is a plan view and a front view of an AT head manufactured according to the present invention, FIGS. 8 to 12 are views showing the prior art, and FIG. 8 is a glass filling treatment with a head core block installed. 9 is a front view, FIG. 10 is a partial perspective view, FIG. 11 is a partially enlarged sectional view, and FIG. 12 is a partially enlarged sectional view of the notch groove of the glass filling jig. 71.81...Head core block, 73.83...
・Track groove, 75.85...Groove, 76.86...Glass rod.

Claims (1)

[Claims] In a method for manufacturing a magnetic head, the method includes a step of filling glass into a track groove of a head core block, after forming a groove in the head core block, a glass rod is placed in the groove to fill the track groove with glass. A method for manufacturing a magnetic head characterized by: