JPS6258409A - Composite magnetic head and its production - Google Patents

Abstract

PURPOSE:To produce easily a high-precision magnetic head by constituting notched grooves of a recording and reproducing magnetic core and an erasing magnetic core as arcuate grooves formed from sides of respective slide faces to a magnetic recording medium. CONSTITUTION:An I block 31 and a C block 32 are joined to constitute a recording and reproducing magnetic core block 30, and an I block 41 and a C block 42 are joined to constitute an erasing magnetic core block 40. Both blocks are joined to constitute a joined block 50, and recording and reproducing side arcuate grooves 36 and erasing side arcuate grooves 46 are formed at prescribed intervals on the joined block 50. These recording and reproducing side arcuate grooves 36 and erasing side arcuate grooves 46 are formed from sides of slide faces to the magnetic recording medium on the recording and reproducing side block 30 and the erasing side block 40. This joined block is cut at prescribed intervals so that a recording and reproducing gap is placed in the center of one magnetic core chip and erasing gaps are placed on both sides.

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.

To solve this crosstalk problem, conventional
A composite magnetic head as shown in FIG. 4 has been proposed. This composite magnetic head has a recording/reproducing gap lO
A pair of erase gaps 20 and 20 scan both sides of the recording track Tw in the width direction recorded by the recording track Tw, thereby forming a guard band Te with almost no signal on both sides of the recording track Tw. By forming the guard bands Te on both sides of the recording track Tw in this manner, crossfeed and crosstalk between adjacent tracks will not occur even if the track spacing is narrowed.

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 include a single-character-shaped half core 12.22,
It is constructed by combining C-shaped half 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. A non-magnetic material 14, 24 such as high melting point glass is interposed in the recording/reproducing gap 10 and the erasing gap 20, for example.

Notch grooves 15 and 15 spanning between the half cores 12 and 13 are formed on both sides of the recording/reproducing gap lO in the width direction. This cutout groove 15.15 regulates the track width Tw, and its inside is filled with a non-magnetic material (generally glass) 16.

Also, at the center of the erase gap 20 in the width direction.

A cutout groove 25 having a width Ew is formed spanning between the half cores 22 and 23. This notch groove 25 is the erase track @
It regulates Te, and the inside thereof is similarly filled with a non-magnetic material 26. The width Ew of the vJ notch groove 25 is approximately the same as or smaller than the recording track @Tv. 32
It is added. Also, the length G of this notch groove 25 in the track direction
1 is usually erase gear 2 to enable reliable erasing.
Usually, the gap interval is set to be 20 times or more the gap interval of the loop 20.

The C-shaped half cores 13 and 23 of the recording/reproducing side magnetic core 11 and the erasing side magnetic core 21 have coils 17.2, respectively.
7 is wrapped.

However, this conventional composite magnetic helad has a notched groove 1.
5 and the notch groove 25 are through grooves machined 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 both magnetic cores 11 and 21, that is, the magnetic path, becomes narrower. Magnetic resistance increases and recording/reproducing efficiency deteriorates. This problem becomes more prominent as magnetic heads become smaller to enable high-density recording, and it is not only a magnetic problem but also a problem that the mechanical strength of both magnetic cores 11 and 21 is poor. occurs at the same time. In addition, in order to increase the recording density on a rotating recording medium, it is desirable to make the interval between the recording/reproducing gap 10 and the erasing gap 20 as small as possible, but in the conventional structure, the half core 1
It is necessary to form the notched grooves 15 and 16 penetrating the 2.degree. half core 22, which requires a thickness of more than a certain value, and therefore it is difficult to reduce this gap.

On the other hand, looking at the manufacturing process of this conventional composite magnetic head, half cores 12 and 13 of the recording/reproducing side magnetic core 11 and half cores 22 and 23 of the erasing side magnetic core 21 are formed as shown by chain lines in FIG. First, it is formed into a block shape, which is then cut into shapes. However, the notch grooves 15 and 25 formed in half cores 12 and 13 and half cores 22 and 23, respectively, are formed before joining half cores 12 and 13 and half cores 22 and 23, respectively, because both grooves are through grooves. However, the notch groove 15. If the half cores 12 and 13 and the half cores 22 and 23 are joined after the notch groove 25 is formed, there is a risk that the groove position will be misaligned at the time of joining. It is clear that high-density recording cannot be achieved unless precision is achieved in groove positioning, and groove positioning also worsens workability.
This complicates the processing process, lowers the yield, and increases costs.

``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 to thicken the magnetic path and increase 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. In addition, the present invention particularly provides a simple manufacturing method in which notch grooves for regulating the recording/reproducing track width and erasing track width for each magnetic core block on the recording/reproducing side and the erasing side can be easily formed, and groove alignment is not required. The purpose is to make it possible to easily manufacture high-precision magnetic heads.

"Summary of the Invention" The composite magnetic head of the present invention solves the problem of conventional products because the notch groove that regulated the recording track width and erasing track width is a through groove that runs the entire length of the magnetic core. This was made based on the discovery that the recording/reproducing magnetic core and the erasing magnetic core each have arcuate grooves, and these are formed from the side of the sliding contact surface with the magnetic recording medium. It is characterized by

The method of the present invention also includes joining a pair of half core blocks to form a recording/reproducing magnetic core block and an erasing magnetic core block, respectively.

Before forming the notch grooves, these two core blocks are joined to form a joined block, and then a rotating grindstone is used to grind the recording track width and erase track onto the sliding contact surface of the magnetic recording medium of this joined block. Arc-shaped grooves regulating the width are formed at predetermined intervals of 1, and then the bonded block is assembled 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 of one magnetic core chip. To,
It is characterized by being cut at predetermined intervals.

"Embodiments of the Invention" The present invention will be described below with reference to illustrated embodiments. Figure 2 (a
) to g) are process diagrams of the manufacturing method according to the present invention. A pair of half core blocks that constitute the magnetic core blocks on the recording/reproducing side and the erasing side are flat! The present invention consists of a block 31.41 and a C block 32.42 having a substantially C-shaped cross section and having a magnetic gap depth regulating groove 34.44, as shown in FIGS. ,
First, I block 31 and C block 32. and! A magnetic core block on the recording and reproducing side (hereinafter simply referred to as the recording and reproducing side block) is formed by joining the block 41 and the C block 42, respectively.
30 and an erase-side magnetic core block (referred to as the erase-side block) 40. In these blocks, an adhesive layer made of a non-magnetic material such as high melting point glass or 5i02 is formed on at least one of the polished joint surfaces by vapor deposition or sputtering. becomes. C block 32.42
The magnetic gap depth regulating grooves 34 and 44 of the block 3 are
1.41 side is open. (2) The block 31.41 and the C block 32.42 are made of, for example, single crystal ferrite, Mn-Zn ferrite, Fe-Al-5i alloy, or the like.

Then, in the present invention, the recording/reproducing side block 30 and the erasing side block 40 are joined to each other to form a joined block 50, as shown in FIG. 3(C). This joint block 5
0 is for joining blocks 31 and 41,
A spacer 51 made of a non-magnetic material such as ceramic or glass is interposed on the bonding surface. Also, I block 31 and C
Block 32) and! Block 41 and C block 42
The upper part of the magnetic gap depth regulating groove 34.44 is filled with a bonding glass 35.45 to increase the bonding strength between the recording/reproducing block 30 and the erasing block 40. One of the features of the present invention is that the recording/reproducing side block 30 and the erasing side block 40 are joined together before the grooves are formed on them.

Next, for this joint block 50, as shown in FIG.
As shown in FIG. 3, recording/reproducing side circular arc grooves 36 and erasing side circular grooves 46 are formed at predetermined intervals. The recording/reproducing side arcuate groove 36 and the erasing side circular arcuate groove 46 are formed on the recording/reproducing side block 30 and the erasing side block 40 from the sliding surface side of the magnetic recording medium. The positions of both arcuate grooves 36.46 are set so that they are shallowest at the joint portions of both core blocks 30.40, that is, at the spacer 51 portions, and the maximum depth is greater than the magnetic gap 33.43. It is designed to occur on the outside (the side far from the spacer 51). Furthermore, the magnetic gap 34 of this arcuate groove 36.46
．． As shown in FIG. 1(C), the depth D at the 44 portion is set to be deeper than the depth d of the magnetic gap 34.44 formed by the magnetic gap depth regulating groove 32.42. prevent magnetic circuits from forming near the

When the notched groove is formed by the arc-shaped groove 36.46, the amount of core material to be removed from the magnetic core block 30.40 is reduced compared to, for example, the case where the notched groove is formed by a groove with a constant depth D. Therefore, the strength of the magnetic core block 30, 40 and the composite magnetic core chip 60 cut out from the magnetic core block 30, 40 can be increased. In addition, since the magnetic path becomes thicker, magnetic resistance can be reduced and recording and reproducing efficiency can be increased.

Specifically, the arcuate grooves 36, 46 can be formed by chopper processing. As shown in Fig. 1(c), chisel milling is a processing method in which a rotating grindstone T is moved toward and away from the workpiece, and by adjusting the depth of cut into the workpiece, the depth of the cut can be adjusted. can be adjusted. When the arcuate grooves 36.46 are formed by this processing method,
Relative movement between the grindstone T and the joint block 50 may be made only in the downward direction and the length direction of the joint block 50 (direction of the rotation axis of the grindstone T), and in the left-right direction (direction of the plane of the grindstone T).
has the advantage of being able to perform highly accurate machining because there is no need to move it. Furthermore, since the grindstone T is not moved in its plane direction, positioning of the grindstone T and the joint block 50 is easy.

On the recording/reproducing side block 30, recording/reproducing gaps 37 are formed at predetermined intervals by the recording/reproducing side circular arc grooves 36.
Erasing gaps 47 are formed at predetermined intervals in the erasing side blow 2 401 by erasing side circular arc grooves 46 . The distance between the recording/reproducing side arcuate groove 36 and the erasing side arcuate groove 46 is determined by cutting the joining block 50 and forming the composite magnetic core chip 6.
0, one recording/reproducing gear 2p 37 is formed in the center of the composite magnetic core chip 60, taking into consideration the cutting line A-A shown in FIG. 2(g) and the width S of the cutting wheel. , so that a pair of erase gaps 47 are formed on both sides.

When this groove machining is completed, the recording/reproducing side arcuate groove 36 and the erasing side arcuate y446 are filled with a non-magnetic material 52 such as glass in a melted and softened state, as shown in FIG. Polishing the sliding contact surface of the block 50 with the magnetic recording medium,
Unnecessary non-magnetic material 52 is removed ((D) in the same figure).

The joining block 50 filled with the non-magnetic material 52 is then cut off along the cutting line B-H using a cutting wheel as shown in FIG. and cut parallel to the arcuate grooves 36, 46. As mentioned above, S is the width of the cutting wheel, and the composite magnetic core chip 60 cut out in this way is shown in FIG.
As shown in a), one recording/reproducing gap 37 is located at the center of the recording/reproducing magnetic core 30A, and a pair of erasing gaps 47 are located on both sides of the erasing magnetic core 4OA.

Composite magnetic core chip 6 cut and formed in this way
Next, as shown in FIG. 1(a), the coil support 38 formed by the magnetic gap depth regulating groove 34.44
and 48, a recording/reproducing coil 39 and an erasing coil 4.
9 is wound, and a backper 53 that closes the magnetic circuits on the recording/reproducing side and the erasing side is bonded to the rear side surface or the rear end surface of the composite magnetic core chip 60, and is further bonded to the slider 61 as shown in FIG. completed. Note that the non-magnetic material 52 is used for this composite magnetic core chip 60 and the slider 61.
When joining, the Q-folding arc-shaped groove 36 and the erase-side arc-shaped groove 46 may be filled.

"Effects of the Invention" As described above, in the composite magnetic head of the present invention, the notch grooves that regulate the recording/reproducing track width and the erasing track width are placed in sliding contact between the magnetic recording medium of the recording/reproducing side magnetic core and the erasing side magnetic core. By forming the arcuate groove from the surface side, the cross-sectional area of the a1 core can be increased, the magnetic path can be thickened, and the mechanical strength can be increased. In other words, since the one-arc groove can minimize the amount of magnetic core material to be removed, the strength of the magnetic core chip is not impaired, and the magnetic path can be made thicker to reduce magnetic resistance and improve recording and reproducing efficiency. can. In addition, arc-shaped grooves can be easily machined using a circular grindstone, and since there is no need to move the grindstone relative to the plane of the arc-shaped groove during processing, positioning is easy and processing accuracy is improved. be able to. Furthermore, being able to shorten the distance between the recording/reproducing gap and the erasing gap is also effective for increasing the recording density. In addition, in the method of the present invention, after joining a pair of blocks constituting the recording/reproducing side block and the erasing side block, one pair of blocks is joined to form a joined block before performing groove processing, and then the joined block is Since the arc-shaped grooves are machined using the same method, work efficiency is improved, the number of times grooves are machined is reduced, and there is no need to align the grooves between the recording/reproducing side block and the erasing side block. Therefore, a highly accurate composite FF head can be easily constructed. Also, from this point of view, a full glass magnetic head can be obtained in which the bonding material for the half core block, the bonding material for the recording/playback side and erasing side blocks, and the filler material filled in the inclined grooves are all made of glass. It also has good workability.

[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 FIG. 1(c) is a perspective view of FIG. 1(a). 2(a) to 2(g) are perspective views showing the manufacturing process of a composite magnetic head according to the present invention, and FIG. 3 is a plan view of a conventional composite magnetic head. , FIG. 4 is a front view of the same. 30... Recording/reproducing side magnetic core block, 30A...
Recording/reproducing side magnetic core, 31... I block (half core block), 32... C block (half core block), 33... Magnetic gap, 34... Magnetic gap depth regulating groove, 36...・Recording/playback side arcuate groove, 37...
・Recording/reproducing gap, 38... Coil support, 40...
・Erasure side magnetic core block, 4OA...Erasure side magnetic core, 41...I/block half core block), 4
2...C block (half core block), 43...
・Magnetic gap, 44...Magnetic gap depth regulation groove,
46... Erasing side arcuate groove, 47... Erasing gap,
48... Coil strut, 50... Joining block, 51
...Spacer, 52...Nonmagnetic material, 60...Composite magnetic core chip, 61...Slider. Patent applicant Alps Electric Co., Ltd. Agent Kunio Miura Shigeru Matsui Figure 1 Figure 2 t Figure 2 Figure 3

Claims (5)

[Claims] (1) a recording/reproducing magnetic core having a recording/reproducing gap and notch grooves located on both sides of the recording/reproducing gap to regulate the recording/reproducing track width; a pair of erasing gaps located on both sides of the recording/reproducing track; and an erasing magnetic core having a notched groove that regulates the erasing track width by the erasing gap. A composite magnetic head characterized by an arcuate groove formed from the side of the surface that comes into sliding contact with the medium. (2) In claim 1, the arcuate grooves formed in the recording/reproducing side magnetic core and the erasing side magnetic core are formed in the composite magnetic head where the arcuate grooves are shallowest at the junction of both magnetic cores. Production method. (3) A step of joining a pair of half core blocks whose joint surfaces form a magnetic gap to form a magnetic core block for recording and reproduction and a magnetic core block for erasing, respectively; the magnetic core block for recording and reproduction and the magnetic core for erasing. A step of joining the blocks to form a joined block; A rotating grindstone is used to form a predetermined arc-shaped groove to regulate the recording track width on the sliding surface side of the magnetic recording medium of the magnetic core block for recording and reproduction of the joined block. a step of forming arcuate grooves for regulating the erase track width at predetermined intervals on the sliding surface side of the erase magnetic core block magnetic recording medium of the joint block using a rotating grindstone; A composite magnetic field comprising the 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. Head manufacturing method. (4) In claim 3, each of the pair of half core blocks constituting the magnetic core block for recording/reproduction and the magnetic core block for erasing, one of which is a flat I block, and the other of which is open on the I block side. A method for manufacturing a composite magnetic head, in which the C block has a substantially C-shaped cross section and has a magnetic gap depth regulating groove, and the joining block is formed by joining the I blocks of both half core blocks. (5) In claim 3 or 4, the arcuate grooves formed in the recording/reproducing side core block and the erasing side core block are shallowest at the joining portion of both blocks. Head manufacturing method.