JPH0585966B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing a magnetic head, and particularly to a method for manufacturing a magnetic head.
This invention relates to a glass bonding method for filling track width control notches in video heads used in VTRs.

A glass embedding method for filling the notch for track width control of a video head used in a conventional VTR is shown in FIGS. 1 to 3. In the figure, 1 is a magnetic ferrite consisting of a pair of rectangular parallelepiped blocks, 2 is a winding groove provided on one side, 3 is a track width control notch, 4 is a magnetic gap, 5 is a glass rod for embedding, and 6 is an embedded glass. 7 is glass for embedding.

In Figure 1, a glass rod 5 is placed above the notch groove 3,
The method shown in Figure 2 is to heat the glass above the working temperature that improves its fluidity and pour the molten glass into the notch groove 3.The method shown in Figure 2 is to place the glass rod 5 in the winding groove 2 and heat it in the same manner as in Figure 1. FIG. 3 shows a method of pouring glass into the notch groove 3 with the notch groove 3 facing down and using capillary action to pour the glass into the notch groove. In the method shown in FIG. 1, bubbles are likely to occur because the distance between the gap depth part that is actually used and the embedded glass is large, and therefore it is necessary to heat it at a temperature considerably higher than the working temperature. The method shown in FIG. 2 can avoid the drawbacks of the method shown in FIG. 1, but the winding holes are likely to become clogged with glass. In addition, even with the method shown in Figure 3, it is necessary to lower the viscosity of the glass, so
It must be heated to a temperature significantly higher than the working temperature.

As described above, in any case, since the glass is heated above the working temperature in order to improve its fluidity, the high melting point glass of the magnetic gap 4 is corroded to some extent, resulting in deterioration of the magnetic properties. Further, in order to prevent this drawback, if glass is poured into the cutout groove 3 at a temperature below or near the working temperature, air bubbles will be generated, and magnetic powder etc. will be buried in the air bubbles, resulting in deterioration of the magnetic properties.

In order to solve these drawbacks, the present invention aims to heat the glass above the softening point and below the working temperature to bond the embedded glass to the magnetic ferrite.
Next, this bonded embedded glass is heated to around the normal working temperature.

That is, the present invention can be said to be a method based on the method shown in FIG. 1 described above, in which the distance between the gap depth portion and the embedded glass is reduced as a result.

An embodiment of the present invention is shown in FIGS. 4a and 4b. 1 is a magnetic ferrite, 2 is a winding groove, 3 is a track width control cutout groove, 4 is a magnetic gap, and 8 is an embedded glass. First, as shown in Figure 1, which shows the conventional method, an embedded glass rod is placed above the winding groove and is placed above the softening point of the glass and below the working temperature (as an example, the softening point
In this example using glass with a working temperature of 420°C and 580°C, work was carried out at 520°C. ) and heat with
Glass 8 is bonded to magnetic ferrite 1 as shown in FIG. 4a. In this state, the glass is not completely embedded in the cutout groove 3, and large bubbles are scattered. However, about half of the embedded part of the notch groove is embedded, so the distance between the gear depth part that is actually used as a magnetic head and the embedded part of the glass is close, and it must be heated a second time to embed it. The volume of the notch groove is approximately 1/2. Furthermore, since the surface of the notch groove is covered with embedded glass, it has good wettability. Therefore, the normal working temperature (in this example, 580
℃), the glass is easily filled into the notched groove without bubbles, resulting in the state shown in FIG. 4b. Working temperature or higher (600℃ or higher when using the glass of this example)
However, in this embodiment, unlike the conventional method, the magnetic gap is never heated at a temperature higher than the working temperature, and the glass embedded in the magnetic gap is not eroded.

As explained above, according to the present invention, glass can be embedded in the track width control notch without bubbles and without corroding the magnetic gap. It goes without saying that the same effects as in this example can be obtained with glasses other than those described in this example by setting an appropriate temperature.

[Brief explanation of the drawing]

1, 2, and 3 are diagrams showing a conventional method for embedding track width control notches in glass, and FIG. 4 is a diagram for explaining a method for embedding track width control notches in glass according to the present invention. be. 1... Magnetic ferrite, 2... Winding groove, 3...
Track width control notch groove, 4...Magnetic gap, 5
...embedded glass, 6...crucible for melting embedded glass, 7,8...embedded glass.

Claims (1)

[Claims] 1. In a method of manufacturing a magnetic head using a pair of magnetic ferrite blocks having a track width control notch and using high softening point glass as a magnetic gap material, the embedded glass is bonded to the non-magnetic glass that fills the notch. Once heated above the softening point of the material and below the normal working temperature, the embedded glass is bonded to the magnetic ferrite, and then heated at the normal working temperature to generate air bubbles in the notch groove for track width control. A method for manufacturing a magnetic head, characterized by embedding glass instead of a magnetic head.