JPS58177514A - Magnetic head core and its manufacture - Google Patents

Abstract

PURPOSE:To secure the strength of reinforcing plates sufficiently, to confirm gap depth directly and to obtain high precision, by fixedly bonding transparent members in such a state that opening ends of notched parts of the reinforcing plates are closed. CONSTITUTION:Each reinforcing plate 6 has a notched part 6a at a position corresponding to a winding window and the side edge side of the opening end side is bonded fixedly so that the notched part is closed by a transparent member 7. Reinforcing plate blocks 8 and 8 have the same sectional shape with the reinforcing plate 6 and are formed so that grooves 8 as notched parts 6a face with each other. The blocks 8 and 8 are confronted with each other with a transparent plate 9 such as a glass plate between. Joint surfaces of the blocks 8 and transparent plate 9 are worked to specific flatness and roughness and a glass material having a lower melting point than the transparent plate 9 is sputtered over the butting surfaces of the block sides 8 to several mum thickness; and those three bodies are stacked and welded thermally in a furnace to be united. The united body is cut at the center part of the transparent plate 9 in the thickness direction and then sliced lengthwise to specific thickness to obtain individual reinforcing plates 6 each having a fixed transparent material 7. Those plates are bonded fixedly with a magnetic core between and polished to complete a magnetic head core.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a magnetic head core and a method for manufacturing the same, and more particularly to a magnetic head core in which a magnetic core is sandwiched between reinforcing plates on both sides, and a method for manufacturing the same.

For example, the narrow track width magnetic Radcore material used in video tape recorders and the like for high-density recording and playback is made of a metal-based magnetic material such as sendust, and can also be used with metal tapes.

The core of this type of magnetic head is extremely thin,
Because it is easily deformed, reinforcing plates are attached to both sides, creating a sand winch structure.

The structure of a conventional magnetic helad core of this type is shown in FIG.

In Fig. 1, the reference numeral 1 indicates a magnetic core, which is integrated by abutting the left and right core halves, has a magnetic gap g and a winding window 2, and has a track width t set to about 10 to 60 μm. has been done. As the track width becomes thinner (particularly t=io~30 μm), the mechanical strength of the magnetic core 1 becomes weaker and cannot withstand winding work. are bonded to increase strength. These reinforcing plates 3 and 4 have cutout portions 3a and 4 whose upper ends are open at positions corresponding to the winding windows 2 of the magnetic core 1.
It has a.

When such reinforcing plates 3 and 4 are used, the notches 3a and 4a
Due to the presence of
This has the disadvantage that the magnetic core may warp or become misaligned in the area, making it unable to function as a reinforcing plate.

Therefore, in order to eliminate such drawbacks, a reinforcing plate 5 as shown in FIG. 2 was proposed. This reinforcing plate 5 has the cutout portion 5a oriented in the horizontal direction, and is intended to increase the reinforcing strength in the vicinity of the magnetic gap g.

However, if such a reinforcing plate structure is adopted, although the strength increases, the existence of the reinforcing plate makes it impossible to check the gap depth, which is absolutely necessary to manage the performance of the magnetic herad core. A method must be adopted to manage depth by setting standards in other areas.

If such an indirect method of confirming the gap depth is adopted, the confirmation accuracy is inevitably lower than that of direct confirmation, which causes variations in the performance of the magnetic head.

The present invention has been made in order to eliminate the above-mentioned drawbacks of the conventional technology, and provides a magnetic helad core configured to sufficiently ensure the strength of the reinforcing plate and to allow direct confirmation of the gap depth. The purpose of the present invention is to provide a method for producing the same.

In order to achieve the above object, in the present invention, a transparent member is adhesively fixed in a state that closes the open end of a notch formed in a reinforcing plate at a position corresponding to a winding window of a magnetic core, and the gap depth is increased. In addition to adopting a structure that allows direct confirmation of the After clamping and fixing with adhesive, the transparent member was cut from the center in the thickness direction and sliced at a predetermined thickness to obtain the intended reinforcing plate.

Hereinafter, the present invention will be described in detail based on embodiments shown in the drawings.

FIG. 3 illustrates a reinforcing plate applied to the magnetic helad core according to the present invention.This reinforcing plate 6 has a notch 6a at a position corresponding to the winding window of the magnetic core, A transparent member 7 is adhesively fixed to the side edge (in FIG. 3, the upper edge side) so as to close the notch. Reinforcement plate 6
Barium titanate or non-magnetic ferrite, which has excellent workability, is used as the material, and glass is used as the transparent member 7.

The reinforcing plate 6 having such a structure is manufactured as shown in FIGS. 4 to 6.

That is, reinforcing plate blocks 8, 8 made of nonmagnetic ferrite, barium titanate, or the like are prepared.

These blocks 8, 8 have the same cross-sectional shape as the intended reinforcing plate 6, and are formed with grooves 8a facing each other to serve as the notches 6a. These blocks 8.8 are arranged facing each other with a transparent plate 9 made of a glass plate or the like interposed therebetween. Block 8
The joint surfaces of the transparent plate 9 are processed to have a certain level of flatness and surface roughness, and a glass material having a melting point lower than that of the glass plate that will become the transparent plate 9 is placed on the butt surface of the block 8 to a thickness of several μm. The three parts are stacked on top of each other and heated and welded in a furnace to integrate them.

Thereafter, the transparent plate 9 is cut at the center in the thickness direction as shown by the broken line in FIG. 5, and sliced at a predetermined thickness along the longitudinal direction, and the transparent member 7 is fixed as shown in FIG. A reinforcing plate 6 is obtained.

The reinforcing plate 6 thus obtained is sandwiched between the magnetic cores and adhesively fixed, both sides are polished, finished to the desired thickness of the magnetic rad core, and wound to obtain a magnetic head core.

The magnetic helad core obtained in this way has a transparent member fixed to the open end of the notch corresponding to the winding window of the magnetic core, so it has excellent mechanical strength and the gap depth can be confirmed through the transparent member. Therefore, warpage and track deviation of the magnetic head core do not occur, and the gap depth, which determines the performance of the magnetic head core, can be reliably managed.

In addition, since the transparent member is reliably bonded, it will not be deformed by heat or damaged even if some external force is applied, making it possible to obtain a magnetic rad core with stable performance and high yield.

Note that either the step of cutting the transparent plate 9 or the step of slicing the reinforcing plate block may be performed first.

As is clear from the above description, according to the present invention, a structure is adopted in which a transparent member is fixed so as to close the open end of the notch facing the winding window of the magnetic core formed in the reinforcing plate. Therefore, the strength is significantly increased, the gap depth can be directly confirmed through the transparent member, gap management can be performed reliably, and the magnetic helad core does not warp or track misalignment.

In addition, the method of cutting the transparent plate and reinforcing plate block by sandwiching the transparent plate and fixing the reinforcing plate block with grooves forming the notches corresponding to the winding windows with the grooves facing each other is adopted. It is easy to mass-produce reinforcing plates having uniform shape and strength, and it is possible to obtain magnetic rad cores with stable performance and high yield.

[Brief explanation of the drawing]

FIG. 1 is an exploded perspective view illustrating a conventional structure, FIG. 2 is a perspective view illustrating another example of a conventional magnetic core, and FIG. 3 is a perspective view of a reinforcing plate applied to the magnetic head core of the present invention. , and FIGS. 4 to 6 are perspective views of manufacturing steps for explaining the method of the present invention.

Claims (2)

[Claims] (1) In a magnetic helad core in which a reinforcing plate having a notch at a position corresponding to the winding window of the magnetic core is sandwiched and adhesively fixed to the magnetic core, a notch is provided at the side edge on the open end side of the notch of the reinforcing plate. A magnetic herad core characterized by having a transparent member fixed thereto. (2) A step of joining a reinforcing plate block in which grooves serving as notches corresponding to the winding windows are continuously formed, with the grooves facing each other and sandwiching the transparent plate, and connecting the transparent plate to the central part in the thickness direction. A method for producing a magnetic helad core, comprising the steps of: cutting the reinforcing plate block with a predetermined thickness;