JPH05210817A - Composite type magnetic head - Google Patents

Abstract

PURPOSE:To decrease ferrite modulation noises and ferrite sliding noises by winding a band fastening member around the cores of the composite type magnetic head consisting of ferrite and magnetic metal. CONSTITUTION:The band fastening member 7 is wound around both cores 5 between a sliding surface 6 and a winding 4. The ferrite modulation noises are mainly generated near a gap and, therefore, compressive force acts by tightening the cores near the gap part, i.e., between the sliding surface 6 and the winding 4 with the band fastening member 7. The magnetic domain structure is then changed form an irregular unstable state to a metastable state by an antimagneto-restriction effect. Consequently, the movement of the magnetic walls decreases and the ferrite modulation noises are decreased. The mechanical vibration by the sliding is suppressed as well by winding the band fastening member 7 and the ferrite sliding noises are decreased as well.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic head, and more particularly, it has a high S / S ratio for recording and reproducing information by sliding contact with a magnetic recording medium.
N magnetic head.

[0002]

2. Description of the Related Art In order to provide a high S / N magnetic head, it is necessary to suppress noise generated by the head itself.
The conventional technique has a winding groove on the abutting surface of at least one magnetic core half of a pair of magnetic core halves, and a coil is formed in this winding groove as described in JP-A-2-282910. In such a magnetic head, the coil is fixed to the magnetic core half body with an adhesive to suppress mechanical vibration of the coil itself, thereby reducing sliding noise generated by resonance of the head. Further, as described in JP-A-2-53211, in a magnetic head in which a core around a magnetic gap portion is cut in order to obtain a predetermined track width, the cut portion is filled with a resin containing an adhesive as a main component. The resin serves as a vibration absorbing material to absorb mechanical vibration during sliding and reduce sliding noise.

[0003]

A composite type magnetic head composed of a ferrite material and a magnetic metal material, when the ferrite exposed on the sliding surface and the medium slide when the signal is reproduced,
Ferrite noise is generated, leading to S / N deterioration. According to experiments by the present inventors, in addition to ferrite sliding noise that occurs regardless of the presence or absence of a signal, ferrite noise is
It has been clarified that there is ferrite modulation noise generated by signal reproduction and tape sliding, which is a major cause of S / N deterioration.

In the prior art, regarding the reduction of ferrite noise, only the reduction of ferrite noise is indirectly considered by alleviating the vibration applied to the head by suppressing the mechanical vibration of the coil and absorbing the tape vibration. However, suppression of domain wall movement, which is greatly related to the occurrence of ferrite modulation noise, is not taken into consideration, and there is a problem that S / N is deteriorated due to the occurrence of ferrite sliding noise and ferrite modulation noise. SUMMARY OF THE INVENTION It is an object of the present invention to solve the above-mentioned problems of the prior art and to provide a composite magnetic head in which ferrite noise generated during signal reproduction is reduced.

[0005]

In order to achieve the above object, a band clamp member is wound around a magnetic core so as to apply stress to the core.

[0006]

[Function] The cause of ferrite sliding noise is the inverse magnetostriction effect due to mechanical vibration caused by the sliding of the ferrite material, but in the case of ferrite modulation noise, it is different from that, and the domain wall of the head core moves stepwise. This is because the magnetic domain structure is in an unstable state due to the occurrence of the above, and the domain wall largely moves even by a small disturbance. Ferrite sliding noise mainly occurs at the edge of the ferrite core near the sliding surface, while ferrite modulation noise mainly occurs near the gap. The wound band-clamping member applies stress to the ferrite core, and due to the inverse magnetostriction effect, the magnetic domain structure changes from an irregular unstable state to a metastable state. As a result, the domain wall movement is reduced, the domain wall movement of the head core due to tape sliding is suppressed, and ferrite modulation noise is reduced. At the same time, mechanical vibration due to tape sliding is suppressed and ferrite sliding noise is also reduced. On the other hand, since the magnetic domain structure of the ferrite core is in a metastable state, the frequency characteristic of reproduction efficiency is improved, and a high S / N composite type magnetic head can be provided.

[0007]

Embodiments of the present invention will be described below with reference to FIGS.

FIG. 1 shows a magnetic head according to the first embodiment of the present invention. In FIG. 1, a magnetic head 1 is composed of a ferrite 2 and a magnetic metal 3, and a winding 4 is wound around both cores 5. A band clamp member 7 is wound around the cores 5 between the sliding surface 6 and the winding 4.

The band-clamping member 7 is adapted to clamp a ferrite core to apply stress. The magnetic domain structure of the head core before banding is composed of an irregular distribution of residual stress when the metal core material is sputtered, a glass material for magnetic gap bonding, or a wall glass material for filling recesses, a metal material, and a ferrite material. The domain wall is weakly pinned due to the imperfection of the residual stress generated at the joint interface between them, and it is in a so-called unstable state. This unstable magnetic domain structure causes a stepwise movement of the magnetic domain wall due to sliding during signal reproduction, resulting in ferrite modulation noise. Since ferrite modulation noise is mainly generated in the vicinity of the gap, when the band clamping member 7 clamps the core in the vicinity of the gap, that is, between the sliding surface 6 and the winding 4, a compressive force is exerted, and a magnetic domain is generated by the inverse magnetostriction effect. The structure changes from an irregular unstable state to a metastable state. As a result, the domain wall movement is reduced, the domain wall movement of the head core due to tape sliding is suppressed, and ferrite modulation noise is reduced. The magnitude of the stress at this time corresponds to a bias magnetic field which is about 1/10 of the saturation magnetic field of the core material, and is determined by the magnetostriction constant and the Young's modulus of the band clamp member 7. By tightening the core in the vicinity of the gap with the band-clamping member 7 in this manner, the domain wall can be maintained in a stable state regardless of whether the magnetostriction constant of the core material is positive or negative, and the head core moves stepwise by sliding. Is suppressed, and ferrite modulation noise can be reduced. Further, by winding the band-clamping member 7, mechanical vibration due to sliding is suppressed and ferrite sliding noise is also reduced. On the other hand, by applying external stress to the ferrite core, the frequency characteristic of reproduction efficiency is improved.

As the band-clamping member 7, metal materials such as copper, steel and aluminum, epoxy type, alkyd type,
A resin such as a silicon-based resin can be used, but a predetermined force can be applied by adjusting the cross-sectional area, so that the effect is the same in any case.

In this embodiment, the belt tightening member 7 is
Although it is provided between the sliding surface 6 and the winding wire 4, the same effect can be obtained also when another band-clamping member 7 is provided around the rear core.

By such a method, it is possible to provide a high S / N composite type magnetic head in which ferrite modulation noise and ferrite sliding noise are reduced.

FIG. 2 shows a magnetic head according to the second embodiment of the present invention. In FIG. 2, the magnetic head 1 is composed of a ferrite 2 and a magnetic metal 3, and a winding 4 is wound around both cores 5. A band clamp member 7 is wound around both cores 5 so as to surround the head element.

The band-clamping member 7 is adapted to clamp the entire core to give stress. By tightening the entire core with the band-clamping member 7, a compressive force is exerted, and due to the inverse magnetostriction effect, the magnetic domain structure changes from an irregular unstable state to a metastable state.
As a result, the domain wall movement is reduced, the domain wall movement of the head core due to tape sliding is suppressed, and ferrite modulation noise is reduced. The magnitude of the stress at this time corresponds to a bias magnetic field which is about 1/10 of the saturation magnetic field of the core material, and is determined by the magnetostriction constant and the Young's modulus of the band clamp member 7. Ferrite modulation noise is mainly generated in the vicinity of the gap portion, but by tightening the entire core with the band-clamping member 7 in this manner, stepwise domain wall movement of the entire head core is suppressed not only in the vicinity of the gap portion but also by sliding, The effect of reducing ferrite modulation noise is increased. Further, by winding the band-clamping member 7, mechanical vibration due to sliding is suppressed and ferrite sliding noise is also reduced. On the other hand, by applying external stress to the ferrite core, the frequency characteristic of reproduction efficiency is improved.

Examples of the band-clamping member 7 include epoxy-based, alkyd-based, and silicon-based resins, and the effect is the same in any case.

By such a method, it is possible to provide a high S / N composite type magnetic head in which ferrite modulation noise and ferrite sliding noise are reduced.

FIG. 3 is a side view of the sliding surface side of the magnetic head according to the third embodiment of the present invention. In FIG. 3, the magnetic head 1
Is composed of ferrite 2 and magnetic metal 3, and a clip 8 is attached to the head 1 with the vicinity of the gap 9 as a contact. The clip 8 has a one-sided opening structure surrounding only one core.

This embodiment is an example in which stress is applied in a direction parallel to the gap surface, the clip 8 and the head element are in contact with each other near the gap 9, and a compressive force perpendicular to the sliding direction is present near the gap. Since it works, the domain wall movement is suppressed and the ferrite modulation noise is reduced as in the first embodiment. Also,
Since the clip 8 is configured to surround only one side core, it is excellent in workability when handling the head element. On the other hand, by applying external stress to the ferrite core, the frequency characteristic of reproduction efficiency is improved.

As the clip 8, a non-magnetic spring material such as a phosphor bronze alloy can be mentioned, but the effect is the same in any case.

Even if the direction of the stress applied to the head core is changed by such a method, the same effect can be obtained, ferrite modulation noise is reduced, and a high S / N composite type magnetic head excellent in workability is provided. You can

FIG. 4 is a side view of the sliding surface side of the magnetic head of the fourth embodiment of the present invention. In FIG. 4, the clip 8 is attached to the head 1 so as to surround only one side of the core with the vicinity of the gap 9 as a contact, and the vicinity of the contact portion is covered with the resin
It is fixed at 0.

By attaching the clip 8, the same effect as in the first and third embodiments can be obtained, and by fixing the clip 8 with the resin 10, the clip 8 can be obtained.
Can be prevented from falling off. Further, mechanical vibration due to sliding is suppressed, and ferrite sliding noise is also reduced.

A non-magnetic spring material such as phosphor bronze alloy can be used as the clip 8, but the effect is the same in any case.

Examples of the resin 10 include epoxy-based, alkyd-based, and silicon-based resins, and the effect is the same in any case.

By such a method, it is possible to provide a high S / N composite type magnetic head in which ferrite modulation noise and ferrite sliding noise are reduced.

FIG. 5 shows a side view on the sliding surface side of the magnetic head of the fifth embodiment of the present invention. In FIG. 5, the clip 8 is attached to the head 1 with the vicinity of the gap 9 as a contact. The clip 8 has a closed structure surrounding both cores.

By attaching the clip 8, the same effect as that of the first embodiment can be obtained, and since the clip 8 is closed and surrounds both cores, its compressive force is larger than that of the single-open type. The magnetic domain structure becomes more stable, and the effect of reducing ferrite modulation noise is increased.

As the clip 8, a non-magnetic spring material such as a phosphor bronze alloy can be used, but the same effect can be obtained in any case.

By such a method, it is possible to provide a high S / N composite type magnetic head with reduced ferrite modulation noise.

FIG. 6 is a side view showing the sliding surface side of the magnetic head of the sixth embodiment of the present invention. In FIG. 6, the clip 8 is attached to the head 1 with the vicinity of the gap 9 as a contact. The clip 8 has a closed structure surrounding both cores, and the vicinity of the contact portion is fixed with resin 10.

By attaching the clip 8, the same effect as in the first and fifth embodiments can be obtained, and by fixing the clip 8 with the resin 10, the clip 8 can be obtained.
Can be prevented from falling off. Further, mechanical vibration due to sliding is suppressed, and ferrite sliding noise is also reduced.

A non-magnetic spring material such as phosphor bronze alloy can be used as the clip 8, but the effect is the same in any case.

Examples of the resin 10 include epoxy-based, alkyd-based, and silicon-based resins, and the effect is the same in any case.

By such a method, it is possible to provide a high S / N composite type magnetic head in which ferrite modulation noise and ferrite sliding noise are reduced.

[0035]

Since the present invention is constructed as described above, it has the following effects.

By winding the band clamp member 7 around the core 5 of the composite type magnetic head composed of the ferrite 2 and the magnetic metal 3, ferrite modulation noise and ferrite sliding noise can be reduced. Therefore, it is possible to provide a high S / N composite type magnetic head in which ferrite noise generated during signal reproduction is reduced.

[Brief description of drawings]

FIG. 1 is a perspective view of a composite magnetic head showing a first embodiment of the present invention.

FIG. 2 is a perspective view of a composite magnetic head showing a second embodiment of the present invention.

FIG. 3 is a front view of a composite magnetic head showing a third embodiment of the present invention.

FIG. 4 is a front view of a composite magnetic head showing a fourth embodiment of the present invention.

FIG. 5 is a front view of a composite magnetic head showing a fifth embodiment of the present invention.

FIG. 6 is a front view of a composite magnetic head showing a sixth embodiment of the present invention.

[Explanation of symbols]

1 ... Magnetic head, 2 ... Ferrite, 3 ... Magnetic metal, 4
... Winding, 5 ... Core, 6 ... Sliding surface, 7 ... Belt tightening member, 8 ... Clip, 9 ... Gap, 10 ... Resin.

Claims (2)

[Claims] 1. A composite magnetic head comprising a ferrite (2) and a magnetic metal (3), wherein a band clamp member (7) is wound around a magnetic core (5). head. 2. The composite magnetic head according to claim 1, wherein the band-clamping member (7) is wound between the sliding surface (6) for the medium and the winding (4).