JPS6299906A - Composite type magnetic head and its manufacture - Google Patents

Abstract

PURPOSE:To decrease the distance between a recording/reproducing gap and an erasure gap and to make the magnetic path thick by forming a wedge having a narrow width at the magnetic gap side to a center core forming the recording/ reproducing gap and the erasure gap. CONSTITUTION:This invention aims at decreasing the gap (l) between the recording/reproducing gap and the erasure gas through the improvement of the shape of the center core and preventing the magnetic path from being made thin regardless of the decreased gap. The wedge 37 having a narrow width at the end of the magnetic gap and having a wider width toward the back side is formed respectively to the center cores 31A of the recording/reproducing side magnetic core and the erasure side magnetic core. In forming the wedge to the center core in this way, the magnetic path is made thick by the expanded width due to the wedge and the distance between the recording/reproducing gap and the erasure gap is decreased.

Description

DETAILED DESCRIPTION OF THE INVENTION TECHNICAL FIELD The present invention relates to a composite magnetic head capable of high-density recording and reproduction, and a method for manufacturing the same.

"Prior art and its problems" In a recording method that forms recording tracks along the circumferential direction of a disc-shaped magnetic recording medium such as a magnetic disk, the track spacing is narrowed to increase the recording density. ,
During recording, crossfeed where adjacent recording tracks overlap, and during reproduction, leakage magnetic flux called crosstalk from adjacent recording tracks tends to occur.

In order to solve this crosstalk problem, composite magnetic heads as shown in FIGS. 3 and 4 have been proposed. This composite magnetic head.

A pair of erasing gaps 20.20
By scanning, on both sides of the recording track W,
By forming the guard bands Te on both sides of the recording track Tv, which have the basic function of forming a guard band Te in a virtually no-signal state, even if the track spacing is narrow, cross-over between adjacent tracks can be avoided. No more feeds or crosstalk.

This conventional composite magnetic head has a magnetic core 1 on the recording/reproducing side.
1 and an erase-side magnetic core 21 are coupled through a non-magnetic layer 29 of ceramics, glass, etc. interposed between the two. The recording/reproducing side magnetic core 11 and the erasing side magnetic core 21 each have a single-character-shaped center core 12.22,
It is constructed by combining C-shaped outer cores 13 and 23, and the gap between them corresponds to the recording/reproducing gap 1, respectively.
0 and an erase gap 20 is formed. In the recording/reproducing gap 10 and the erasing gap 20, a non-magnetic material 14, such as high melting point glass, is provided. ．． 24 is intervening.

Notch grooves 15 and 15 are formed on both sides of the recording/reproducing gap 10 in the width direction, spanning between the center core 12 and the outer core 13. This cutout groove 15.15 regulates the above-mentioned track width ↑, and inside it, a non-magnetic material (-
The shell is filled with glass) 16.

Further, the widthwise center g of the erase gap 2G is a notch groove 25 of %Ev spanning between the center core 22 and the outer core 23.
is formed. This 9J notch groove 25 regulates the L recording track width Te, and the inside thereof is similarly filled with a nonmagnetic material 26. The width E%l of the notch groove 25 is as follows.
It is set to be approximately the same as or smaller than the recording track width Tw. Also, the length G1 of this notch groove 25 in the track direction
To enable reliable erasing, the erasing gap 2 is usually
The gap interval is set to 20 times or more of the zero gap interval.

The C-shaped outer cores 13 and 23 of the recording/reproducing side magnetic core 11 and the erasing side magnetic core 21 are provided with coils 1, 7, .
27 is wrapped.

However, in this conventional composite magnetic head, the notch groove 1
5 and the notch groove 25 are grooves processed over the entire length of the recording/reproducing side magnetic core 11 and the erasing side magnetic core 21, so the cross-sectional area of the re-magnetic cores 11 and 21, that is, the magnetic path, becomes narrower. The magnetic resistance increases, and the recording and reproducing efficiency is affected. This problem can be solved by miniaturizing the magnetic spatula 13, which makes high-density recording possible. In addition to the magnetic problem, this re-magnetic core 11.21
At the same time, the problem of poor mechanical strength also arises. Furthermore, in order to increase the recording density on a rotating recording medium, it is desirable to make the distance between the recording/reproducing gap 10 and the erasing gap 20 as small as possible. It is necessary to form .16 1-, and it is necessary to form a thickness of L above a certain value.
, Therefore, it was difficult to reduce the size of this interval sentence.

On the other hand, in the structure of this conventional composite magnetic head, the center core 12 and outer core 13 of the magnetic core 11 on the recording/reproducing side and the center core 22 and outer core 23 of the magnetic core 21 on the erasing side are As shown by the chain line in the figure, it is formed into a block shape, which is later cut.
The notch grooves 15 and 25 formed in the cores 12 and 13, respectively, are formed in the cores 12 and 13, respectively, of the sixth units (IJ4 grooves pass through) 1 to 5.
, and before joining the cores 22 and 23, and then joining both. However, after forming the notch grooves 15 and 25 in this way, the cores 12 and 13
, and the cores 22 and 23, there is a risk that the groove position will be out of order at the time of joining. It is clear that high-density recording cannot be achieved unless precision is achieved in groove positioning.Also, groove positioning deteriorates workability, complicates the processing process, reduces yield, and increases costs. do.

``Object of the Invention'' Based on the above-mentioned awareness of the problems with conventional composite magnetic heads, the present invention increases the cross-sectional area of the magnetic core, thickens the magnetic path, and increases the mechanical strength.

It is an object of the present invention to provide a composite magnetic head that narrows the distance between a recording/reproducing gap and an erasing gap and is easy to manufacture. Another object of the present invention is to obtain a composite magnetic head in which the distance between the magnetic gap on the recording/reproducing side and the magnetic gap on the erasing side can be narrowed.

The method of the present invention provides a method for efficiently and easily manufacturing such a composite magnetic head.

"Summary of the Invention" The composite magnetic head of the present invention improves the shape of the center core of conventional products to reduce the distance between the recording/reproducing gap and the erasing gap, and prevents the magnetic path from becoming narrow even when the distance is reduced. It is characterized in that the center cores of the recording/reproducing side magnetic core and the erasing side magnetic core are each formed with a wedge-shaped portion that is narrow at the end on the 81 air gap side and widens toward the rear. By forming the wedge-shaped portion in the center core in this manner, the magnetic path can be made thicker by the amount of width increased by the wedge-shaped portion. S11 In other words, the interval between the recording/reproducing gap and the erasing gap can be reduced.

Furthermore, the method of the present invention provides a method for easily manufacturing the above-mentioned magnetic head. First, a pair of center core blocks are each formed into a cross-sectional shape and joined together to form a center block. An outer core block is bonded to both center core blocks of the center block, and a magnetic gap for recording/reproducing and erasing is formed on the joint surface, and a recording/reproducing gap and an erasing magnetic gap are formed on the center block and the outer core block. After forming the notch grooves that regulate the width of the gap, this bonding block is inserted at predetermined intervals so that the recording/reproducing gap is located at the center of one magnetic core chip and the erasing gap is located at both sides. The feature is that it can be cut.

"Embodiments of the Invention" The present invention will be described below with reference to illustrated embodiments. Figure 2 C&
) to e) are process diagrams of the manufacturing method according to the present invention.
1 are joined to form the central block 30. 32 is a spacer interposed between the joint surfaces. This central block 30
Next, the magnetic gap forming surfaces 33 and 34 on both sides are polished to give the center core blocks 31 and 31 a cross-sectional shape. Although the center core block 31 may be polished into a wedge-shaped cross section in advance and then bonded, it is easier to process the center core block 31 by polishing it into a wedge-shaped cross section after bonding.

On the other hand, the magnetic gap forming surface 33 of this central block 30.
Outer core blocks 40, 41 to be joined to 34 are separately formed. This outer core block 40.41 is formed with an inclined magnetic gap forming surface 42.43 corresponding to the magnetic gap forming surface 33.34, and a magnetic gap depth regulating groove 45 is formed in this magnetic gap forming surface 42.43.
．． 46 and spacer relief grooves, etc. are formed. Magnetic gap forming materials 47 and 48 such as high-melting glass are inserted into the magnetic gap depth regulating grooves 45 and 46, respectively, and by heating and melting the materials, outer core blocks 40 and 48 are formed on both sides of the central block 30. are joined to form a joined block 50. This joint surface is formed by connecting the narrow end of the wedge-shaped center core block 31 to the magnetic gap 3.
It becomes 5.36. Since the magnetic gap forming surfaces 42 and 43 are inclined, this joining block 50 has a rectangular cross section, which facilitates subsequent processing. Note that these blocks include, for example, single crystal ferrite, Mn-Zn ferrite,
It is composed of a magnetic material such as a Fe-Al-5i alloy.

This joint block 50 is then subjected to foot molding. This processing is to form winding grooves 51.52 in the joining block 50 from the opposite side of the magnetic gap 35.36, as shown by chain lines in FIG. 2(b). The winding grooves 51.52 are formed at positions where wedge-shaped portions 37.37 are left at the ends of the center core block 31 on the side of the magnetic gaps 35 and 36. In other words, magnetic gaps 35 and 36
This wedge-shaped portion 3 is set in a sufficiently short interval.
7.37, the positions of the winding grooves 51 and 52 are determined so that the effective width of the center core block 31 is expanded, resulting in an increase in mechanical strength and a thicker magnetic path.

The width of the center core block 31 when the center core blow 2 31 is formed into a flat plate shape and the distance between the magnetic gaps 35 and 36 is narrowed as in the present invention is shown by the chain line in FIG. 37. If you compare the case where 37 is formed, it will be understood that the mechanical strength of the center core block 31 increases and the magnetic path becomes thicker.
next! This notch groove processing, which is performed by uJ notch groove machining, is to form a plurality of inclined grooves 53, which are inclined with respect to the magnetic gaps 35 and 36, in parallel at regular intervals on the surface of the joint block 50 (see FIG. (d).

(e)), the inclination angle of this inclined groove 53 to the direction orthogonal to the magnetic gaps 35 and 36 is 0 (see (e) in the same figure), which is formed by the cutting process in consideration of the spacing between the magnetic gaps 35 and 36. One magnetic gap 35 is located at the center in the width direction of the magnetic core depth 60, and a pair of magnetic gaps 36 are located at the ends. Specifically, good results can be obtained by setting the angle in the range of 5° to 30°. This inclined groove 53 is made of a non-magnetic material 5 such as a low melting point glass by a well-known means.
4 is filled.

The surface (sliding contact surface with the magnetic recording medium) of the bonding block 50 filled with the non-magnetic material lI454 is then polished and moved to the next cutting step, where magnetic core chips 60 of 1 width W are cut out. In this cutting process, the joining block 50 is cut at right angles to the magnetic gaps 35 and 36. The cutting distance is S, the magnetic gap 35 is located at the center of the magnetic core chip 60 of @W, and this magnetic gap 35 and have a pair of magnetic gaps 3 at each end at different positions in the perpendicular direction.
Position 6.

FIG. 1(a) shows a magnetic core chip 60 cut out in this manner. In this figure and FIG. 2(e), the magnetic gap 35 is shown as a recording/reproducing gap 38, and the magnetic gap 36 is shown as an erasing gap 39. Further, the center core is denoted by 31A, and the outer cores are denoted by 40A and 41A.

As shown in FIG. 1(a), the magnetic core chip 60 has coils 55° and 56 wound around its winding grooves 51 and 52.
Further, a backper 65 is attached to the side or back surface of the opposite end of the recording/reproducing gap 38, 39 to complete the process.

The backper 65 is made by integrating a recording/reproducing side backper 66 and an erasing side backper 67 made of magnetic material with a non-magnetic material 68 such as glass sandwiched between them, and is attached to the rear side of the magnetic core chip 60. Join. Bonding can be performed using well-known bonding materials such as glass and resin. -66 to the Q re-side back and -67 to the erase side back are respectively,
This is to close the magnetic paths on the recording/reproducing side and the erasing side, and by integrating the nonmagnetic material 68 with the nonmagnetic material 68 in between, it becomes easy to bond it to the magnetic core chip 60.

FIG. 1(b) shows a state in which sliders 59 and 59 are bonded to both sides of this magnetic core chip 60.

Note that the present invention does not limit the method of forming the νJ notch grooves that regulate the ends of the recording/reproducing gap 38 and the erasing cap 39. That is, in the above embodiment, the inclined groove 52 is formed by J:, but it may be formed by any method other than the inclined groove 52.

"Effects of the Invention" As described below, the composite magnetic head of the present invention has a recording II
Since a patterned part with a narrow width on the magnetic gap side is formed on the center core that forms the f raw gear 2 and the erase gap, mechanical strength can be maintained even if the distance between the recording/reproducing gear 2 and the erase gap is set small. The magnetic path can be made thicker without causing any damage.

Therefore, a composite magnetic head capable of high recording density can be provided. Furthermore, in the method of the present invention, a pair of wedge-shaped center core blowers 2 are first joined to form a central block, and an outer core block is joined to this central block, so that the magnetic head of the present invention can be manufactured efficiently. be able to.

[Brief explanation of drawings]

FIG. 1(a) is a perspective view of a completed state showing an embodiment of a composite magnetic head according to the present invention, FIG. 1(b) is a perspective view of a state in which a slider is joined, and FIGS. 1 A perspective view showing the manufacturing process of a composite magnetic head according to the present invention,
e) is a plan view, FIG. 3 is a plan view of a conventional composite magnetic head, and FIG. 4 is a front view thereof. 30... Center block, 31... Center core block, 31A... Center core, 32... Spacer, 3
3.34...Magnetic Yap forming surface, 35.36...
Magnetic gap, 37... Pattern portion, 38... Recording/reproducing gap, 39... Erasing gap, 40.41...
Outer core block, 4OA, 41A... Outer core, 42.43... Magnetic layer forming surface, 44.45.
...Magnetic gap depth regulating groove, 50...Joining block, 51.52...8 line groove, 53...Slanted groove (notch I
M), 55.56-y Il, 59-S9 I! ,
60...Magnetic core chip, 65...Back bar. Patent applicant Alps Electric Co., Ltd. Agent Kunio Miura Shigeru Matsui Figure 1 Figure 2 (a) Figure 2 Figure 3 Figure 4

Claims (3)

[Claims] (1) A recording/reproducing side magnetic core in which a recording/reproducing gap is formed on the joining surface of a center core and an outer core; and a pair of erasing gaps located on both sides of the recording/reproducing track on the joining surface of another center core and an outer core. In a composite magnetic head in which the recording/reproducing side magnetic core and the erasing side magnetic core have their center cores joined to each other, the center cores of the recording/reproducing side magnetic core and the erasing side magnetic core respectively have magnetic A composite magnetic head characterized by forming a wedge-shaped part that is narrow at the end on the gap side and widens toward the rear. (2) A center block forming step in which a pair of center core blocks are each formed into a wedge-shaped cross section and joined together to form a center block; an outer core block is joined to both center core blocks of this center block, respectively, and the joint surface a joining block forming step for forming magnetic gaps for recording/reproducing and erasing; and a notch groove forming step for forming notched grooves for regulating the widths of the recording/reproducing gap and the erasing magnetic gap on the central block and the outer core block. and; a cutting step of cutting the bonded block at predetermined intervals so that a recording/reproducing gap is located at the center of one magnetic core chip and erasing gaps are located at both sides. A method for manufacturing a composite magnetic head. (3) In claim 2, the center block forming step includes, after joining the flat center core blocks,
A method for manufacturing a composite magnetic head in which a center core block with a wedge-shaped cross section is formed by polishing the opposite side of the bonding surface.