JPH01251306A - Magnetic flux generator - Google Patents

Abstract

PURPOSE:To concentrate magnetic flux in a small area by covering the magnetic pole part of a magnetic core with a cover made of superconducting material and generating the magnetic flux concentratedly through a small through hole formed through the cover. CONSTITUTION:A recording and reproducing coil 2 is wound on a core 1 and a cover made of the superconducting material is fitted in the magnetic pole part of its one end. The cover 3 has an almost rectangular parallelepiped shape and the magnetic pole part of the core 1 is fitted clossely in a rectangular hole part formed on the upper side of the cover 3. A through hole 4 is formed from the bottom part of the rectangular hole to the lower face of the cover 3. Consequently, slitting high-density magnetic flux whose sectional shape is thin can be operated on a medium 5, therefore, even when a main magnetic pole of a conventional opposed head is eliminated, high-performance recording can be performed. Thus, the forming the through hole sufficiently thin, much magnetic flux can be concentrated in the very small area.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a magnetic flux generating device applied to, for example, a magnetic head or a deflection yoke, and particularly relates to a technique for concentrating high-density magnetic flux in a very small area.

2. Description of the Related Art In order to increase the recording density of information in, for example, a magnetic recording/reproducing device, a magnetic head is required that generates high-density magnetic flux in a predetermined form in a very small area. In the ring-shaped head of a typical magnetic disk drive, a high magnetic permeability material is placed in the gap part of the core to concentrate more magnetic flux into a small magnetic pole (metal-in-gap head). Furthermore, in the ring type head for perpendicular magnetization recording/reproducing described in Japanese Patent Application Laid-Open No. 57-120221,
A superconducting material is inserted into the gap of the core to eliminate the magnetic flux that directly crosses the gap and to increase the magnetic flux that bulges outside the gap. In the field of perpendicular magnetic recording, several types of heads are known, such as a facing type head in which a main magnetic pole and an auxiliary magnetic pole face each other.
Each has advantages and disadvantages.

Problems to be Solved by the Invention In order to generate high-density magnetic flux with a small cross-sectional area, it is necessary to use a material with high magnetic permeability and saturation magnetic flux density for the magnetic pole pieces, and to devise the form of the magnetic poles so as not to diffuse the magnetic flux. Must be. Even if a material with high magnetic permeability is used, if the cross-sectional area of the magnetic path of the magnetic pole is made small, magnetic saturation will occur in that area, making it impossible to generate high-density magnetic flux. On the other hand, if you increase the cross-sectional area of the magnetic path of the magnetic pole, magnetic saturation becomes less likely to occur, but the cross-sectional area of the magnetic flux generated from it also increases.
Unable to concentrate magnetic flux.

This invention was made in view of the above-mentioned conventional problems, and its purpose is to make it possible to concentrate the magnetic flux generated from a magnetic pole with a large saturation magnetic flux density (the cross-sectional area of the magnetic path is large) into a very small area. An object of the present invention is to provide a magnetic flux generating device.

Means to Solve the Problem In the present invention, the magnetic pole portion of the magnetic core is covered with a cover made of superconducting material, and magnetic flux is generated intensively through a small through hole formed in the cover.

Due to the Meissner effect (the property that magnetic flux does not enter the inside of a superconductor) of the working superconducting material, the magnetic flux emitted from the magnetic pole into space is bent by the cover made of the superconducting material, and the magnetic flux is bent by the cover made of the superconducting material. Concentrate on the through hole.

Embodiment FIG. 1 shows the structure of a perpendicular magnetization recording/reproducing head according to an embodiment of the present invention. A recording/reproducing coil 2 is wound around a prismatic magnetic core 1, and a cover 3 made of superconducting material is attached to a magnetic pole portion at one end of the coil 2. The cover 3 has an approximately rectangular parallelepiped outer shape, and the magnetic pole portion of the core 1 is fitted into a square hole formed on the upper surface thereof. A through hole 4 is formed extending from the bottom of this square hole to the lower surface of the cover 3. The opening shape of the through hole 4 on the lower surface of the cover 3 is in the shape of a thin slit as shown in FIG. CB). Note that 5 is a magnetic recording medium.

When a current is passed through the coil 2 to excite the core l, its upper and lower ends become magnetic poles, and a magnetic flux is generated that connects the two magnetic poles and spreads in the surrounding space. The dotted line in the figure indicates magnetic flux. cover 3
At the magnetic pole part at the lower end of the core 1, where the magnetic flux is attached, the magnetic flux generated in the space cannot enter the cover 3 (Meissner effect of superconducting material), so the magnetic flux follows the irregular shape of the cover 3 as shown in the figure. It bends and exits through the through hole 4.

Here, if the magnetic pole cross-sectional area of the core 1 is SI, the average magnetic flux density near the magnetic pole is Bl, the cross-sectional area of the lower opening of the through hole 4 is S', and the magnetic flux density near this opening is B2, then the magnetic flux According to the conservation law, S + X B 1 "" S 2X B 2 holds true. Therefore, the magnetic flux density B near the bottom opening of the through hole 4 is as follows, and the smaller the opening area S2 of the through hole 4 is, the larger the magnetic flux density B2 becomes. In other words, all the magnetic flux generated by the magnetic poles gathers in the small through hole 4, υ, resulting in a large magnetic flux density.

According to the head of this embodiment, a high-density magnetic flux in the form of a slit with a narrow cross-sectional shape can be applied to the medium 5, so even if the main magnetic pole in the conventional facing type head is eliminated,
Capable of high-performance magnetic recording.

FIG. 2 shows a ring-shaped head for perpendicular magnetization recording and reproducing improved according to the present invention. The core 1 is shaped more like a U-shape than a ring, and the coil 2 is wound around its center. The core l is almost entirely enclosed in a cover 3 made of superconducting material. Cover 3 has core 1
Two through holes 4a and 4b are formed that reach the top surface of the cover 3 from the magnetic pole faces at both ends. The opening shapes of the through holes 4a and 4b on the upper surface of the cover 3 are two parallel slits as shown in FIG. 2(G).

The magnetic flux generated to connect both magnetic poles of the core 1 passes through the - side through hole 4a, exits to the upper surface side of the cover 3, curves in a U-shape in the space, passes through the other through hole 4b, and connects to the magnetic pole. reach.

Here, in order to make the cross-sectional shape of the magnetic flux acting on the recording medium 5 sufficiently thin, the opening shape of the through hole 4as4b of the cover 3 should be made into a thin slit shape, and the shape of the magnetic pole of the core 1 should be such that magnetic saturation does not occur. can be made large enough to

FIG. 3 shows the configuration of a magnetic flux generator according to a third embodiment of the present invention. The core 1 is C-shaped, and a coil 2 is wound around the center. The core 1 is entirely enclosed in a cover 3 made of superconducting material. The cover 3 has a recess 6 inserted into the gap portion of the core 1, and has an outer shape close to a C-shape as a whole. Small through holes 4a and 4b are formed from two opposing surfaces of the recess 6 in the cover 3 toward the magnetic pole surface of the internal core. These two through-holes 4a and 4b are, for example, round holes, and are formed aligned in the same straight line. The magnetic flux generated from one magnetic pole of the core 1 is narrowed by the through hole 4a, crosses the space of the recess 6, and flows through the through hole 4.
b and reaches the other magnetic pole. By reducing the cross-sectional area of the through holes 4a and 4b, an extremely thin and strong magnetic flux can be generated in the recess 6. In this embodiment, a precise and strong deflection yoke can be constructed.

Effects of the Invention As explained in detail above, in the magnetic flux generating device according to the present invention, the magnetic pole portion of the core is covered with a cover made of a superconducting material that does not allow magnetic flux to pass through, and the through hole formed in this cover is used as a magnetic path. Therefore, by forming the through hole sufficiently thin, a large amount of magnetic flux can be concentrated in a very small area. There is no need to reduce the size of the core magnetic pole for this magnetic flux concentration, and therefore the problem of not being able to sufficiently increase the magnetic flux density due to magnetic saturation as in the prior art is solved. The present invention makes it possible to realize a high-performance magnetic head as shown in the embodiments, leading to various useful effects such as greatly increasing the recording density of information.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram of a magnetic head according to a first embodiment of the present invention, FIG. 2 is a schematic diagram of a magnetic head according to a second embodiment of the present invention, and FIG. 3 is a diagram of a magnetic head according to a third embodiment of the present invention. FIG. 1 is a schematic configuration diagram of a magnetic flux generator. DESCRIPTION OF SYMBOLS 1... Magnetic core, 2... Coil, 3... Superconducting material cover, 4.4a, 4b... Through hole, 5... Magnetic recording medium, 6... Recessed part. Name of agent: Patent attorney Toshio Nakao and 1 other person No. 1
Figure 2 (Figure 3)

Claims (1)

[Claims] A magnetic flux generator in which the magnetic pole part of the magnetic core is covered with a cover made of superconducting material, and magnetic flux is generated in a concentrated manner through small through holes formed in the cover.