JPS63247902A - Magnetic head - Google Patents

Abstract

PURPOSE:To improve the saturation magnetic flux density and wear resistance of a magnetic core, by forming a magnetic core half body on an upstream side in the sliding direction of a magnetic medium with Fe-B alloy, and forming the magnetic core half body on a downstream side with an oxide magnetic material. CONSTITUTION:A ferrite core half body 1 is formed with ferrite that is the oxide magnetic material with high permeability as the magnetic core half body. Also, an Fe-B core half body 2 is formed with the Fe-B group alloy as the magnetic core half body similarly. The magnetic core is constituted by butting and jointing the half bodies 1 and 2 via a magnetic gap 4. Track grooves 6 and 6' which decide the track width of the gap 4 at the both side parts of the gap 4 on respective butting plane of the half bodies 1 and 2 are formed, and glass 3 is filled in the grooves 6 and 6', and the half bodies 1 and 2 are joined by welding the glass 3. Also, a winding window 5 is formed on the half body 2, and an erasing head is constituted by winding the coil wire via the winding window 5. Thus, it is possible to improve the saturation magnetic flux density and the wear resistance of the magnetic core.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a magnetic head that records, reproduces, or erases information by sliding a magnetic core relative to a magnetic recording medium, and particularly relates to a magnetic head that records, reproduces, or erases information by sliding a magnetic core relative to a magnetic recording medium. The present invention relates to a magnetic head such as a rotary erase head used in a magnetic core that requires high saturation magnetic flux density and high wear resistance.

[Prior Art] A single-gap rotary erasing head used in a VTR requires the following.

a) The saturation magnetic flux density of the magnetic core is high because high-density recording is performed on a magnetic tape with high coercive force.

b) In order to reduce erase power consumption, eddy current loss is small and the Q of the magnetic core is high, making it easy to obtain resonance in the magnetic circuit.

C) The magnetic core has excellent wear resistance because it comes into sliding contact with the magnetic tape at high speed.

In order to meet these demands, conventional single-gap rotary erasing heads employ structures as shown in FIGS. 4 to 6 as the structure of the magnetic core. That is, first, the fourth
In the structure shown in the figure, the magnetic core is constructed by butt-joining ferrite core halves l and 1' made of ferrite i, which are oxide magnetic materials, through a magnetic gap 4, respectively. Further, in the structure shown in FIG. 5, the magnetic core is constructed by joining center core halves 7 and 7' made of sendust through a magnetic ganging 4 as magnetic core fonts. The core shown in Figure 6 is a so-called composite core, with a ferrite core half made of ferrite.
A magnetic core is constructed by joining a Sendust core half body 7' made of Sendust and a Sendust core half 7' through a magnetic gap 4.

Track grooves 6 and 6' are formed on both sides of the magnetic camp 4 at the abutting surfaces of the respective core halves to determine the track width of the magnetic gap 4, and this trunk groove 6 is formed on both sides of the magnetic camp 4.
．． 6' is filled with glass 3, and the core halves are joined by welding the glass 3. Also, a winding window 5 is formed in one of the magnetic core halves, and the winding window 5 is used to connect the core halves. A coil (not shown)! A magnetic head is constructed by winding the J3 wire around a magnetic core.

[Problems to be Solved by the Invention] However, such a structure has the following problems with respect to the requirements a to C described above.

That is, first, the structure shown in Fig. 4 lacks the saturation magnetic flux density due to the characteristics of ferrite.6 Also, in the magnetic core shown in Fig. 5, the eddy current loss is large due to the low specific resistance of sendust, resulting in a low Q. , Sendust has a problem in that it has inferior wear resistance compared to ferrite. Although the structure shown in Fig. 6 satisfies the saturation f magnetic flux density and Q, the sendust core half 7', which has poor wear resistance, wears on one side, and the shape of the magnetic tape sliding surface deforms, causing the head There was a problem that the touch deteriorated.

[Means for Solving the Problems] In order to solve these problems, according to the present invention, a magnetic core formed by joining a pair of m-score halves through a magnetic gap is fixed relative to a magnetic recording medium. Record information by sliding,
In a magnetic head for reproducing or erasing, the magnetic core half on the first stream side of the sliding direction of the medium is formed from an Fe-B alloy, and the magnetic core half on the downstream side is formed from an oxide magnetic material. structure was adopted.

[Function] According to the Fe-B alloy core material, wear resistance is significantly higher than Sendust and close to ferrite, which is an oxide magnetic material, and saturation magnetic flux density is significantly higher than ferrite, which is similar to Sendust. Close to. Therefore, such Fe
- According to the above-mentioned magnetic core structure using a combination of B-based alloy and ferrite, which is an oxide magnetic material, both saturation magnetic flux density and wear resistance are improved compared to the conventional structure described above. be able to.

[Embodiment] Hereinafter, details of an embodiment of the present invention will be explained with reference to FIG. 1 and subsequent figures.

FIG. 1 shows the structure of the magnetic core of the single camp rotary erase head of the VTR described above as an embodiment of the present invention.

In FIG. 1, reference numeral 1 denotes a ferrite core half made of ferrite, which is an oxide magnetic material with high magnetic permeability, as a magnetic core half. Further, reference numeral 2 designates an Fe-B core half made of an Fe-B alloy, which also includes a magnetic core. The magnetic core of this embodiment is constructed by butting and joining a ferrite core half 1 and an Fe-B core half 2 with a magnetic gap 4 interposed therebetween. There is a magnetic gap 4 on both sides of the magnetic gap 4 at the point where both core halves 1.2 butt each other.
A track groove 6.degree. 6' is formed to determine the track width of the core, and this track groove is filled with glass 3, and by welding the glass 3, both core halves 1.2 are joined. Also,
In this case, a winding window 5 is formed in the Fe--B core half, and a coil winding (not shown) is wound around the magnetic core through the winding window 5 to form an erasing head.

By the way, as a characteristic of Fe-B alloy, firstly, it has a high wear resistance almost equivalent to that of ferrite.

Figure 2 shows this.As a magnetic core wear test, a magnetic tape was slid on each magnetic core made of sendust, Fe-B alloy, and ferrite, and the running time of the magnetic tape and each This shows the results of measuring the relationship between the amount of wear. As is clear from this figure, the amount of wear of the Fe-B alloy is significantly smaller than that of Centast and is close to that of ferrite.

Further, as a characteristic of the Fe-B alloy, it has a high saturation magnetic flux density close to centast. That is, the saturation magnetic flux density of Sendust is 8,000 to 10,000 Gauss, whereas the saturation magnetic flux density of Fe-B alloy is about 7,000 Gauss.

According to the structure of the magnetic core of this embodiment, the saturation magnetic flux density can be increased compared to the conventional example shown in FIG. Moreover, the wear resistance of the magnetic core can be improved compared to the conventional examples shown in FIGS. 5 and 6, and the ferrite and Fe-
Since there is little difference in the surface abrasion properties of the B-based alloys, uneven wear of the magnetic core can also be prevented. Further, by using ferrite having a high resistivity for one core half 1, it is possible to construct an efficient magnetic core with a higher resistivity, less eddy current, and a higher Q than a Sendust core.

In addition, in the structure of the magnetic core of this example north of this, Fe
-B The core half 2 is placed on the upstream side in the magnetic tape sliding direction shown by the arrow in FIG. 1, and the ferrite core half 1 is placed on the downstream side in the magnetic tape sliding direction. With this arrangement, the magnetic field generated near the magnetic gap 4 has two instantaneous rises and a gradual fall in the magnetic tape sliding direction, as shown by the solid line in FIG. If both core bodies (a) and (b) are made of ferrite, which is ideal as an erasing magnetic field, the rise and fall of the generated magnetic field will have similar curves, as shown by the broken line in the same figure. On the other hand, in the case of this embodiment, erasing can be performed satisfactorily using the magnetic field as described above.

[Effects of the Invention] As is clear from the description below, according to the present invention, a magnetic core formed by joining a pair of magnetic core halves through a magnetic gap is made to slide relative to a magnetic recording medium. recording information,
In a magnetic head for reading or erasing, the magnetic core half on the upstream side in the sliding direction of the medium is formed from an Fe-B alloy, and the magnetic core half on the downstream side is formed from an oxide magnetic material. By adopting this method, it is possible to improve wear resistance as well as the saturation magnetic flux density of the magnetic core, and to improve efficiency and reduce power consumption, which is an excellent effect.

[Brief explanation of drawings]

FIG. 1 is a perspective view showing the structure of a magnetic core of a magnetic head according to an embodiment of the present invention, and FIG. 2 shows the sliding running time of a magnetic tape in a magnetic core wear test and the relationship between magnetic cores made of different core materials. Figure 3 is a diagram showing the relationship between the amount of wear, and Figure 4 is an explanatory diagram showing the difference in magnetic fields generated near the magnetic gap.
6 are perspective views showing the structures of magnetic cores of different conventional magnetic heads. l... Ferrite core half body 2... Fe-8 core half body 3... Glass 4... Magnetic gap 5...
・Winding window 6.6'...Track groove Fig. 4

Claims (1)

[Claims] In a magnetic head that records, reproduces, or erases information by sliding a magnetic core formed by joining a pair of magnetic core halves through a magnetic gap relative to a magnetic recording medium, upstream in the sliding direction of the medium. A magnetic head characterized in that the magnetic core half on the side is formed from an Fe-B alloy, and the magnetic core half on the downstream side is formed from an oxide magnetic material.