JPH03137807A - Production of magnetic head - Google Patents

Abstract

PURPOSE:To prevent the generation of bubbles in glass near a gap part by installing glass rods respectively to both sides of the gap part of a head core block, then packing the glass into track grooves. CONSTITUTION:The head core block 51 is adhered to a prescribed mounting base by an inorg. adhesive agent or the like and one piece each of the glass rods 53 are installed on both sides of the gap part 52 so as to evade the gap part 52 and thereafter, the block 51 and the glass rods 53 are heated to about 700 deg.C in the case of execution of glass packing in the block 51 formed with the track grooves 54 on a front surface 56. The glass rods 53 are then melted and are packed into the track grooves 54. The molten glass flows from the glass rods 53 to both directions as shown by arrows when the respective glass rods 53 are positioned at the intermediate of the gap part 52 and the end edge 57 of the front surface of the block 51. The glass is thus packed uniformly into the track grooves 54.

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]

Magnetic tapes used in conventional consumer VTRs generally use iron oxide recording media, but 8mmV
Magnetic recording devices with high recording densities, such as TR and DAT, are being improved in quality by using metal-based recording media with high coercive force.

In order to fully exploit the characteristics of a magnetic tape, it is generally said that the saturation magnetic flux density (hereinafter referred to as B) of the head material needs to be five times or more the coercive force (hereinafter referred to as H6) of the tape. Iron oxide H6 is about 600 (Oe), and metal tape is about 1400 (Oe).

On the other hand, the B 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 a BS of 7000G or more is required. Therefore, metal magnetic materials with high B8 (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 track width regulating grooves are formed before the head core halves 1a and 1b are bonded together to form a gap, and then the track width regulating grooves are formed. The groove is filled with glass 2.

However, in order to manufacture this bulk type head, tracks are processed on the core halves 1a and 1b before the gap is formed, so a high precision technique is required when welding the core halves 1a and 1b 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 7th fl (a) and (b)). This magnetic head is called an all-track head (hereinafter referred to as an AT head) because its entire width is a track, as shown in FIG. 7(a).

As shown in (b), this AT head has a pair of helad core halves 10a and 10b welded together, and a track 1.
The track width regulating groove 12 forming the tape 1 is filled with glass 13, and the glass 13 is exposed on the tape sliding surface.

When manufacturing this AT head, first, a pair of rod-shaped head core block halves 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 (arc-shaped) on the tape sliding surface of the head core block after glass filling. R-polishing process to form a curved surface shape (e.g., curved surface shape), sliding surface processing process to process the R-polished tape sliding surface, and after processing the sliding surface, the head chip is sliced in a direction parallel to the track groove. Processing is performed in the order of the slicing process to form.

[Problem to be solved by the invention]

In the manufacturing process of the magnetic head described above, especially in the glass filling process, as shown in FIG. After installing the glass rod 53 on the gap portion 52, the temperature of the glass rod 53 was raised to about 700° C. to melt the glass rod 53 and fill the track groove 54 with glass. At this time, the molten glass flows as shown by arrow A in the figure and fills the track groove 54.

However, when filling the glass, the head core block 51
Since the area near the gap is exposed to the molten glass for the longest time compared to other areas, the sendust 62 and glass 63 near the gap 61 that are in contact with the tape are The reaction became more intense,
There was a problem in that bubbles 64 were generated in the glass 63, making the head chip 60 defective and reducing the yield.

The present invention was made to solve such problems,
The present invention aims to provide a method for manufacturing a magnetic head that can prevent bubbles from forming in the glass near the gap in a glass filling process.

[Means to solve the problem]

The method for manufacturing a magnetic head according to the present invention includes the step of filling the track grooves of the head core block with glass after forming the gap, wherein glass rods are installed on both sides of the gap portion of the head core block. After that, the track grooves are filled with glass.

[Effect]

In the present invention, since molten glass flows into the track groove from both sides of the gap, the gap and the vicinity of the gap are not separated from high-temperature glass for a long time.

〔Example〕

The present invention is based on the premise that it is used in a manufacturing process using a rod-shaped head core block 51 (for example, made of a ferromagnetic metal material) for an AT head. As shown in FIG. 5, the head core block 51 is subjected to various processes including track addition, IC1, glass filling (d), R polishing (e), sliding surface processing (f), and slicing (g), and finally as shown in FIG. 7(a). A head chip 41 as shown in (b) is manufactured.

As shown in FIG. 1, when performing glass filling processing on the head core block 51 with the track grooves 54 formed on the upper surface 56, the head core block 51 is attached to a predetermined mounting base using an inorganic adhesive (this adhesive is The head core block 51 is bonded with a material that can withstand a glass filling temperature of 700°C, etc., and one glass rod 53 is installed on each side of the gap 52, avoiding the gap 52. When the glass rod 53 and the glass rod 53 are heated to nearly 700° C., the glass rod 53 is melted and the track groove 54 is filled with glass. At this time, the molten glass made by melting the glass rods 53 is
1, the glass rod 53 flows in both directions as shown by the arrows in FIG. 2 and fills the track groove 54 uniformly.

Further, when the glass rod 53 is disposed close to the upper edge 57 of the head core block 51 as shown in FIG. 3, the molten glass flows in the direction of the arrow and fills the track groove 54. Ru. Furthermore, as shown in FIG.
3 are provided on each side of the gap portion 52, the molten glass flows within the track groove 54 as shown by the arrow, and is filled more uniformly. As described above, in the present invention, at least one glass rod 53 may be provided on both sides of the gap portion 52.

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 reference numerals in each figure indicate the same or corresponding parts.

〔Effect of the invention〕

As explained above, the present invention installs glass rods on both sides of the gap portion of the head core block, and then melts the glass rods to fill the track grooves with glass, so that the gap portion is not exposed to high temperature glass. This shortens the time required for the glass to cool, and prevents bubbles from forming in the glass near the gap.

[Brief explanation of the drawing]

Figures 1 to 4 are diagrams showing one embodiment of the present invention.
The figure is a perspective view of the head core block, Figure 2 is an explanatory diagram showing the flow of molten glass when a pair of glass rods is placed between the gap and the edge, and Figure 3 is a perspective view of the head core block. Figure 4 is a diagram equivalent to Figure 2 when placed near the edge of the core block, Figure 4 is a diagram equivalent to Figure 2 when two glass rods are placed on each side of the gap, and Figure 5 is a head core. Perspective view showing the state in which the block is processed, No. 6
Figures (a) and (b) are a plan view and a front view of the bulk type head,
7(a) and 7(b) are a plan view and a front view of an AT head manufactured according to the present invention, FIG. 8 is a perspective view of a head core block and a glass rod showing the conventional technology, and FIG. 9 is a conventional AT head. FIG. 2 is a perspective view showing a part of the external appearance of the Herad chip. 51...Head core block, 52...Gap portion, 53...Glass rod, 54...Track groove.

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 gap, in which glass rods are installed on both sides of the gap portion of the head core block, and then glass is filled into the track groove. A method of manufacturing a magnetic head, characterized in that: