JPS6032105A - Magnetic head - Google Patents

Abstract

PURPOSE:To prevent the deterioration of characteristics of a magnetic head by providing an elastic material which absorbs the injecting pressure of synthetic resin at the side of a magnetic core assembly which is stored into a holder in order to avoid the core breakage and the gap opening due to said injecting pressure. CONSTITUTION:A core assembly contains a butted gap spacer 3, a coil bobbin 5, a coil 4 and a connection terminal 6. An elastic material 10 made of one or more of natural rubber, urethane rubber, silicone rubber, foaming synthetic resin, etc. is put between cores 2 and 2 of said assembly. Then this assembly is put into a holder 7. The holder contains a tape guide 8 and an attachment foot 9 formed in a body. Then synthetic resin is injected into the holder 7 and hardened. In this case, a sufficient amount of resin is injected so as to avoid the shortage of resin, the generation of nests, etc. The material 10 functions effectively to avoid that the gap space is increased and the cores 2 are broken by said injecting pressure. In this way, the production of a magnetic head having high performance is ensured with high yield.

Description

TECHNICAL FIELD The present invention relates to a magnetic head, and more particularly to a magnetic head having a structure in which a magnetic core is housed in a holder and fixed with synthetic resin.

Prior Art The structure of a conventional magnetic head of this type is shown in FIGS. 1 and 2.

FIG. 1 explains the core assembly. This core assembly 1 is formed into a ring shape by abutting a pair of left and right core half-holes 2.2, and there is a gap at the tip side of the core half-holes 2.2. A spacer 3 is interposed to form a magnetic gap.

2 Further, a winding 4 is provided on the proximal end sides of the core halves 2, 2 so as to cover the abutting portions thereof.

This winding 4 is wound around a coil bobbin 5 fitted on the proximal end side of the core half-hole 2.2.

Further, a connection terminal 6 is molded integrally with the coil bobbin 5. The core assembly 1 having such a structure has a second
It is fitted into the holder T shown in the figure, and is integrally fixed to the holder T side by injecting resin.

In the case of the example shown in FIG. 2, the tape guide 8 is provided integrally with the holder T, and the mounting legs 9 are still integrally provided on the sides of the holder 7.

By the way, the core assembly is housed in the holder in this way,
If a structure in which the core halves are integrated using molten synthetic resin is adopted, an accident may occur in which the core halves 2, 2 are damaged due to the pressure of the injected synthetic resin. This damage accident is particularly common when ferrite is used as the material for the core half body 2.

Furthermore, the gap may become wider due to the pressure of the injected synthetic resin.

The reason for this inconvenience is that a large amount of synthetic resin is injected for fixing the core assembly, and that the pressure at which this resin is injected is not completely controlled. That is, the amount of synthetic resin injected is generally relatively large. The reason for this is to prevent a shortage of synthetic resin and the occurrence of cavities within the holder.

Furthermore, it is impossible to completely control the pressure during injection due to the structure of the mold used during injection, the fluidity of the resin, and the rapid application of injection pressure.

Therefore, it has been considered that the above-mentioned problems caused by the solidification of the resin are unavoidable.

Purpose The present invention was made in view of the above circumstances, and it is an object of the present invention to provide a magnetic head configured to prevent accidents such as core damage and gap opening from occurring.

EXAMPLES Hereinafter, the present invention will be explained in detail based on examples shown in the drawings.

3 and 4 illustrate one embodiment of the present invention. In each figure, the same or corresponding parts as in FIGS. 1 and 2 are designated by the same reference numerals, and their explanation will be omitted. .

In this embodiment, as shown in FIG. 3, a structure is adopted in which an elastic body 10 is provided in the space between a pair of abutted near halves 2.2 constituting the core assembly 1.

This elastic body 10 has sufficient elasticity and has the property of deforming its volume and contracting when external force is applied thereto.

Materials include natural rubber, urethane rubber, silicone rubber,
Foamed synthetic resin etc. are used.

In this way, when the core assembly is housed in the holder 7 with the elastic body 10 installed on the core assembly 1 side and molten synthetic resin is injected, if more resin is injected than necessary, the elastic body The body 10 contracts and becomes smaller to absorb the pressure during injection.

Therefore, fluctuations in pressure during resin injection will not cause problems with the elastic body, and the electrical characteristics of the magnetic head will not deteriorate.

Figures 5 and 6 show the relationship between molding time and magnetic core pressure during synthetic resin sealing, and show the conventional example (Figure 5).
FIG. 6 is a graph diagram for comparing the present invention example (FIG. 6) and FIG.

In Figures 5 and 6, A and A' are resin injection starting points.

It is a point. As shown in the figure, the pressure applied to the magnetic core increases rapidly from the time the resin is filled, and reaches its maximum at the point where the resin injection is completed.

In FIG. 5, which shows a conventional example, since this pressure exceeds the bending strength (F line) of the ferrite core, cracks occur in the magnetic core made of ferrite material.

However, in FIG. 6, which shows an example of the present invention, this pressure is less than the transverse tensile strength F of the ferrite core, so it does not adversely affect the magnetic core of the ferrite material.

Effects As is clear from the above explanation, according to the present invention, a structure is adopted in which an elastic body is provided on the side of the core assembly housed in the holder to absorb the injection pressure of the synthetic resin, so that the synthetic resin is Can absorb molding pressure when injected,
This has the excellent effect of not causing accidents such as damage to the core or opening of a gap, and not deteriorating the electrical characteristics of the magnetic head.

FIG. 1 is a perspective view of a core assembly, FIG. 2 is a perspective view of a completed magnetic head, FIGS. 3 and 4 illustrate an embodiment of the present invention, and FIG. 3 is a perspective view of a core assembly. FIG. 4 is a perspective view of a completed magnetic head, FIG. 5 is a graph showing the relationship between molding time and magnetic core pressure in the conventional structure, and FIG. 6 is the molding time in the structure of the present invention. FIG. 7 is a graph diagram showing the relationship between the magnetic core pressure and the magnetic core pressure.

DESCRIPTION OF SYMBOLS 1... Core assembly 2... Core half-break 3... Gap spacer 4... Coil 5. Coil bobbin 6... Connection terminal 7... Holder 10... Elastic body.

Patent applicant: Canon Electronics Co., Ltd. Figure 1 Figure 2 Figure 3 Figure 4

Claims (2)

[Claims] (1) A magnetic head in which a core assembly is housed in a holder and integrated by injecting and solidifying a synthetic resin, characterized in that an elastic body that deforms in volume is provided on the core assembly side. (2) Natural rubber and urea as elastic bodies that undergo volume deformation