JPS6379206A - Manufacture for magnetic head - Google Patents

Abstract

PURPOSE:To improve the reliability of head by cutting a groove to a face with core block halves butted and joined while leaving the part of track width, imbedding and molding glass and joining the halves by the hot hydrostatic pressing method. CONSTITUTION:A winding locking outer groove 22 is cut to a core block half 20 and a track groove 26 is cut to form a projecting teeth 25 having a prescribed slice pitch with a track width Tw. Then a low melting point glass 27 is imbedded and molded to the track groove 26 to make the molding flat. On the other hand, a winding groove 28, teeth 29 are cut to a core block half 21, the low melting point glass 27 is imbedded and molded, then a notch part 30 is provided. Moreover, an SiO2 film 32 having a film thickness Lg is adhered onto a magnetic gap forming scheduled part 31. The halves 20, 21 are opposed to each other and they are bonded by the hot hydrostatic pressure method. Since the main part of the cores is deposited and enclosed by the glass, the deterioration in the characteristic is prevented and the reliability is improved.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method of manufacturing a magnetic head such as a VTR that requires high recording density, and particularly relates to a joining technique for magnetic helad cores.

Traditionally, magnetic heads of this type have used magnetic material cores that have excellent magnetic properties such as high magnetic permeability, resistive magnetic force, and high saturation magnetic flux density.

The magnetic material core is generally made of Mn--Zn ferrite, which has been praised for its excellent properties as described above, extremely high resistivity, and good high-frequency properties. but,
In recent magnetic heads, the magnetic material of the magnetic recording medium is J'-Fe2O2, which is obtained from conventional acicular goethite particles, which has a limit in saturation magnetic flux density.
-Since the use of metal magnetic powder with a main composition of Ni has been realized, as a core material that satisfies the corresponding high saturation magnetic flux density, for example, as introduced in JP-A-58-18918, Fe A sendust alloy core whose main composition is -5l-At is about to be put into practical use. However, the sendust alloy core has lower workability than ferrite, and has the following problems in manufacturing the core.

In other words, the conventional ferrite, as shown in FIG.
A flat abutting portion 4 of a block piece 3 with a cutout recess 2 provided near the upper corner 1 to form a window for passing through the coil winding, and a flat abutting portion 4 of a block piece 6 having an upper corner 5 facing the upper limit it. The abutting portion 7 is bonded with a low melting point glass 8 which is an adhesive.
It is assembled by joining and fixing it.

However, when changing the material to sendust alloy, low melting point glass has poor wettability and becomes difficult to bond.

Therefore, the adhesive used is one that is compatible with the Zendust alloy, such as a brazing filler metal. That is, as shown in FIG. 6, a sendust core block 3-6' is prepared, and a flat abutting portion 4' is bonded using Ag solder 9 as an adhesive.
, 7' are adhered, and a film 10 of S10 is applied as a magnetic gap spacer to the abutting surface of the upper corner 5 to form a pack gap h and a magnetic gap g, and a closed magnetic path l shown by a broken line 11 is provided. , operating at short recording wavelengths, the magnetic gap 2 dimension is set to several thousand.

Il　I　　′　　　　.

However, since the Sendust alloy magnetic head described above is an alloy, it has a low resistivity, and as a result, eddy currents tend to occur in high frequency bands, resulting in large eddy current losses. In order to correct this drawback, it is necessary to reduce the core thickness to about the track width dimension, but if the core thickness is made thinner, it will naturally become difficult to join the cores. Also, as shown in Figure 6,
When bonded using Ag solder 9, A
There is also the problem that g is diffused during bonding, resulting in an increase in the pack gap h, which lowers the efficiency of the magnetic head, especially during output reproduction.

This invention was proposed for the purpose of solving the above problems.

As a means of solving the problem, this invention forms track grooves on both sides of the convex tooth part in a core block half of a large number of cores so that the part corresponding to the thick bone of the core becomes a convex tooth part. However, a glass mold is applied to these track grooves, and the core block halves are joined together using hot isostatic pressing. In other words, although this invention is suitable for increasing recording density, it has been a barrier in terms of core bonding. Brazing is an attempt to eliminate bonding and establish a technology that can achieve sufficient adhesion.

1. According to this invention, the core halves are hot isostatically pressed with the convex tooth portion including the magnetic gap and pack gap, and the portion where no track groove is formed, that is, the outer frame portion that does not function as a core. The glass molded into the track grooves serves to prevent damage to the magnetic gap when slicing the bonded core block into individual cores, and to protect the main parts of the completed core.

1L-FIG. 4 are perspective views of a magnetic head core block or conceptual diagrams of a hot isostatic press forming apparatus for explaining an embodiment of the present invention. First, the core block halves 20 and 2I shown in FIGS. 1 and 2 form a pair to be butt-jointed, and are made of Si9. G, AjG,
2. It is a sendust alloy with a composition of balance Fe 84.2 (each wt%). First, one core block half 20 is formed by cutting a winding locking outer groove 22, and then forming an outer frame 2 on a joint surface 23.
Except for No. 4, the track grooves 2Ei, 2G, ... are cut in order to form convex teeth 25.25, ... with a track width Tw and a predetermined slice pitch interval, and then the track grooves 211i, 2B, ... has a softening point of 4
00~soo”c low melting point glass 27.27,・
... is embedded and molded. The joint surface 23 of this core block half body 20 is made of low melting point glass 27, 27, etc. by, for example, diamond lapping.
・The protrusions are polished and the surface is finished flat.

Next, the other core block half 21 has a winding locking groove 28, convex teeth 29, 29, .
... to form a low melting point glass 27.27. After embedding and molding..., near the magnetic gap forming end,
A boat-shaped penetrating notch groove 30 is provided in a direction perpendicular to the convex teeth 29, 29, . Further, a 510 mm film 32 having a thickness equal to the gap length Lg is adhered as a cap spacer onto the ribbon-shaped magnetic gear forming portion 31.

Now, the core block halves 20 and 21 explained above are placed on a butt jig and sandwiched together with the joining surfaces 23 and 23 facing each other, and then heated as shown in Fig. 3. Place in an isostatic pressure forming device. This hot isostatic press forming apparatus 33 includes a high-pressure cylinder 34 provided in a press room surrounded by an explosion-proof wall, with an upper lid 35 tightly fitted to its upper end and a lower lid 38 to its lower end. . Further, a heat insulating material 37 is stretched over the inner wall surface, a heater 38 is arranged in a helical shape inside the heat insulating material 37, and a die 39 is set on the lower lid 3B. In this hot isostatic press forming apparatus, an atmospheric gas such as Ar gas is introduced into an internal space 40, and a core is clamped onto a die 38 in the internal space 40 as shown in FIG. Insert the block halves 20.21. Then, while raising the temperature of the heater 38 in the range of 700°C-IOOO°C, Ar gas is sealed into the high-pressure cylinder 34 and pressurized to 300 to 400 atmospheres to perform hot isostatic pressurization.

The top end surface of the core block 41 joined in the state shown in FIG. 41, where the magnetic gap g is formed, is polished to a curved surface as shown by the dashed line, and the thin wires 42, 42 . By slicing along ..., the desired sendust alloy magnetic rad core can be obtained. Note that the work steps other than those described above are the same as before and will not be described.

The following summer, F and 1 were disappointed.

According to this invention, the bare butting surfaces of the core are joined by hot isostatic pressing, and also include the magnetic gap, and the main part of the core is surrounded by glass by welding, so that the magnetic gap can be destroyed and the back gap can be Expansion prevents damage to the magnetic head and deterioration of its characteristics, and also improves the yield during manufacturing of the magnetic head core, eliminates air bubbles in the glass that protects the core, and improves the compatibility between the core and the glass. reliability is significantly improved.

[Brief explanation of the drawing]

1 and 2 are perspective views of half a core block of a magnetic herad core used in an embodiment of the present invention, and FIG.
A conceptual diagram of a hot isostatic pressure forming apparatus for performing core joining, FIG. 4 is a perspective view of the core blocks in abutted state, FIG. 5 is a front view of a conventional ferrite magnetic head core, and FIG. 6 is a front view of a typical Sendust magnetic herad core. 20.21... Core block half body, 25.2i11... Convex tooth portion, 2B... Track groove,
27...Glass (low melting point glass), g...Magnetic gap.

Claims (1)

[Claims] Track grooves are formed on both sides of the convex tooth part in the core block half of the multi-core part so that a portion corresponding to the thickness of the core becomes a convex tooth part, and a glass mold is applied to the track groove, A method for manufacturing a magnetic head, characterized in that the core block halves are joined together by hot isostatic pressing.