JPS62165712A - Manufacture of magnetic head - Google Patents

Abstract

PURPOSE:To bond core halves suitably by sticking a reinforcement core to both faces of a main core, projecting a laser beam to a welding body through the main core to melt the welding body thereby bonding a couple of core halves at a front gap. CONSTITUTION:Amorphous core halves 1a, 1b are subjected to application of butt pressure F1 and an upper/lower depressing pressure F2 and laser beams R1, R2 and R are projected to plural back gaps 2 from the upper direction. Thus, a circular crystal substance 10 corresponding to a laser beam spot is produced up to the rear face. A welding body 5 made of a material such as a low temperature solder member having a thickness equal to that of the main core 3 is inserted into a triangle part of a front edge of a coil winding hole 4 of the main core 3 formed in this way. Then a part corresponding to a depth end of a front gap G is made of a transparent glass 7, a reinforcement core 6 of a hybrid with a magnetic substance 8 such as a ferrite is stuck to both side of the main core 3 by a proper adhesives.

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Field of Industrial Application The present invention relates to a magnetic head used in a VTR or the like, and particularly to an amorphous magnetic head using an amorphous metal material.

(b) Conventional technology The structure of a magnetic head consisting of a main core consisting of a pair of amorphous core halves and reinforcing cores on both sides of the main core and its manufacturing method are disclosed in, for example, Japanese Patent Laid-Open No. 58-32218. The method disclosed in JP-A-58-133620 involves stacking amorphous metal plates and reinforcing cores alternately, joining the core halves together in the form of a block, and processing. Then, it is cut out into head chip units. Apart from such conventional examples, core halves made of a pair of amorphous metal plates are joined face-to-face with a gap formed without stacking blocks, or the main core formed in this way is For example, the present applicant has disclosed an invention relating to a manufacturing method for an amorphous magnetic head in which reinforcing cores are bonded to both sides.
No. 908 and patent application No. 59-2631858 were filed. The former method involves joining the main core and the reinforcing core at their sides by laser beam spot welding, thereby combining the amorphous core halves at the same time. In the latter method, a laser beam is irradiated to a plurality of locations including the front gap depth end portion of the abutting portion of a pair of amorphous core halves to form a crystalline portion and join the amorphous core halves.

(c) Problems to be solved by the invention However, in the former case, the amorphous core halves are indirectly joined together without any means for joining them, so the formation There is a problem in that misalignment and gap opening occur depending on how the bonding crystal is formed. In the latter case, although it is sufficient to bond the back gap, a crystalline material is provided at the lower end of the depth end of the front gap.
Since the crystalline material in this part plays the role of setting the depth end, it is formed relatively small, and therefore there is a problem that the bond between the two core halves at the front gap part is weak.

The present invention solves the above-mentioned problems in an amorphous magnetic head in which a pair of core halves made of amorphous metal plates are joined together and reinforcing cores are arranged on both sides.

In the present invention, a pair of amorphous core halves are irradiated with a laser beam while abutting pressure is applied to form a crystalline material in the back gap. A weld is applied adjacent to the gap end of the coil winding hole defining the gap end of the front gap, and a weld is applied to both sides of the main core. A reinforcing core is attached, and the welded body is irradiated with a laser beam through the main core to melt the welded body, thereby joining the pair of core halves at the front gap portion.

←Synchronization Effect When the back gap is irradiated with a laser beam, crystalline material corresponding to the beam spot is formed in both halves including the back gap. This crystalline material has significantly reduced magnetic properties, but has binding properties.

Next, the front end of the coil winding hole of the main core formed by combining these core halves defines the depth end of the front gap, and a solid welded body is inserted into the front end of this coil winding hole. be done. Reinforcement cores are attached to both sides of the main core. Thereafter, the solid welded body is rapidly melted by a laser beam irradiated through the reinforcing core, and the solid welded body is fused between the core halves.

At this time, since the welded body is instantaneously melted by the laser beam and only needs to be heated for a short time, there is little thermal influence on the base material (amorphous core).

(f) Example Fig. 2 (in 8, amorphous core half (1a) (
1b) as shown in the figure, a laser beam (R
1) Apply (R2) and (R3) to multiple locations on the back gap (2). As a result, a circular crystalline material a0 corresponding to the laser beam spot is formed even on the back surface.

A welded body (5) having the same thickness as the main core (3) is inserted into the triangular portion at the front end of the coil winding hole (4) of the soil core (3) thus formed. This welded body (5) is a thin brazing material or a powdered brazing material. The brazing material used here is a low-temperature solder material, and the conditions for this low-temperature solder material are that it flows quickly and smoothly in a molten state, and that its melting temperature is lower than the crystallization temperature of the main core (3), which is 480°C to 500°C. , and must be sufficiently compatible with the ball core (3). γ
Go and Fe, which are the main components of Morphus material, are easily compatible with PB, so they are used in soft solder alloys with a high PB content, such as 5n-
An alloy such as pb (75-50 width) may be used. Next, as shown in Fig. 3, the reinforcing core (6) is made of transparent glass (7) at least in the portion corresponding to the front gap tGl depth end of the main core, and a magnetic material such as ferrite (8). ), or is it a hybrid type with
Alternatively, as shown in Fig. 4, it is made of a single plate of transparent glass (9). This reinforcing core (6) is attached to both sides of the king core (3) using a suitable adhesive as shown in FIG. 2) to obtain tC in FIG. Next, a laser beam (R4) is irradiated toward the welded body (5) through the transparent part of the reinforcing core (6). The energy density of the laser beam (R4) at this time is 0.4 to 1. OW/d, and irradiation is performed under normal soldering conditions. Dissolved gas and the like generated during laser beam irradiation are discharged from the coil winding hole (4) of the reinforcing core (6), so that bubble nests and the like that cause a decrease in strength do not occur. FIG. 2 [C1 head chip is completed as shown in FIG. 1 by further polishing the tape contacting surface with R.

(G) Effects of the Invention According to the present invention, not only the back gap but also the front gap are sufficiently firmly connected to improve performance. Furthermore, since the method involves directly applying the coupling means to the core halves, the pair of core halves can be suitably coupled. In addition, since a small laser beam spot can be used, it is possible to solder minute parts, and the short time heating by the laser beam reduces the thermal effect on the main core.

[Brief explanation of drawings]

FIG. 1 is a perspective view of a magnetic head formed by the method of the present invention. FIG. 2 is a diagram showing the method of the present invention, and the third
4 and 4 are perspective views of the parts used. (la) (11:+)... Core half, (2)... Back gap, (3)... Main core, (4)... Coil winding hole, (5)... Welded body, (6)...Reinforcement core, Mouth 0...Crystalline, (R+) to (R4)...Laser beam, (G)...Front gap.

Claims (3)

[Claims] (1) A pair of core halves made of amorphous are irradiated with a laser beam while abutting pressure is applied to form a crystalline material in the back gap portion, thereby bonding the back portions.
Thereby, a main core is formed, and then a weld is applied close to the gap end portion of the coil winding hole that defines the gap end of the front gap, and reinforcing cores are pasted on both sides of the main core, A method for manufacturing a magnetic head, in which the welded body is irradiated with a laser beam through the main core to melt the welded body, thereby joining the pair of core halves at the front gap portion. (2) The manufacturing method according to claim 1, characterized in that a low-temperature solder material is used as the welded body. (3) Claim 2, characterized in that a soft solder alloy with a high Pb content is used as the low-temperature solder material.
The manufacturing method described in section.