JPH0383209A - Production of magnetic head - Google Patents

Abstract

PURPOSE:To polish a head block at high accuracy by rotating a disk abrasive material which has a specified shape in the cross section of the outer circumference, using a working bench which moves back and forth along the direction perpendicular to the rotation axis of the abrasive material, attaching the head core block which can be easily detached with the longitu dinal axis thereof along the moving direction of the working bench, and then allowing the outer circumference of the abrasive material to come into contact with the block surface. CONSTITUTION:A blade of grinding wheel 121 having the circumference end with recessed circular arc is mounted on a dicer not shown in the figure. The blade 121 is rotated about the axis h in the direction shown by an arrow (i), while the blade is raised or lowered in the direction shown by an arrow (j). The head core block 21 is attached to a working bench 123 which moves back and forth along the rotation direction of the outer circumference 122 of the blade 121. The block 21, which can be also detached from the bench, is mounted in a manner that the longitudinal axis thereof is in the moving direction of the bench 123 and the surface thereof is made to come into contact with the outer circumference 122 for polishing into an R shape. Namely, the working bench 123 is made to move continuously along the direction (k), while the blade 121 is rotated and lowered gradually to the bench 123 to remove unnecessary parts of the block 21.

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention relates to a manufacturing method for manufacturing a magnetic head used in information recording and reproducing devices such as video tape recorders (VTRs) and digital audio tape recorders (DATs). Regarding.

[Conventional technology]

Magnetic tapes used in conventional consumer VTRs generally use iron oxide recording media, but 8mmV
High quality magnetic recording devices such as TR and DAT are being improved by using metal-based recording media with high coercive force.

In order to bring out the full characteristics of a magnetic tape, it is generally said that the saturation magnetic flux density (hereinafter referred to as B) of the head material must be five times or more the coercive force (hereinafter referred to as H) of the tape. Iron oxide H is approximately 600 (Oe)
In the case of metal tape, it is approximately 1400 (Oe).

On the other hand, the B of oxide magnetic material (ferrite), which is the magnetic head material used in consumer VTRs, is approximately 50.
Since it is 00G, it is more than 5 times and sufficient for iron oxide tape, but it is less than 5 times for metal tape, so 1400X5 is necessary to bring out its characteristics.
= 7000, and B of 7000G or more is required. Therefore, metal magnetic materials with high B (such as Sendust) have come to be used as magnetic head materials.

The first magnetic head using this type of sendust is
The structures shown in FIGS. 7(a) and 7(b) are known.

The magnetic head shown in the figure is called a "bulk type head", and a track width regulating groove is formed before the head core halves la and lb are joined together, and then a glass plate is placed in the track width regulating groove. The structure is filled with.

FIGS. 6 to 15 show a method of manufacturing such a bulk type magnetic head manufactured by Sendust. To explain the outline of this manufacturing method, first, the sixth
As shown in the figure, a pair of rod-shaped materials 61 made of Sendust and having a rectangular cross section are blade-processed with a gusher to remove burr, and one of the materials 61 is provided with a groove 62 for a winding window and a winding window. A groove 63 around the wire frame is formed to form a head core block half body 61b (FIG. 7), and a groove 64 around the winding frame is formed in the other material 61 to form a head core block half body 61a. Next, each block half 61a, 61
After forming track grooves 66 and 67 on the joint surface 65 of b (
(Fig. 8), joint surface 65 of each block half-closed 61a, 61b
(Fig. 9), and then each block half 61
A gap spacer 68 is formed by electron beam evaporation of AIOSS i 02 or the like on the bonding surface 65 of a161b (
(FIG. 1O) Next, the head core block 61 having the track grooves 69 is formed by joining the block halves 61a and 61b by silver soldering and performing track alignment (FIG. 11).
The glass 70 is filled in (Fig. 12 (a), (b)).
).

Here, the same figure (a) shows the state before glass filling, in which the bar-shaped glass 70 before melting is inserted into the groove 62 for the winding window, and the same figure (b) shows the state in which the bar-shaped glass 70 is inserted into the groove 62 for the winding window. It shows a state in which the track groove 69 is filled by being heated and melted. Next, the tape sliding surface 71 is formed into an R shape (a curved surface shape such as an arc shape).
13), the head core block 61 is sliced at a predetermined angle in a direction intersecting the elongated direction, and a predetermined polishing process is performed to form a head chip 81. ), then this head chip 81 is attached and fixed to the head base 82 (FIG. 15). In addition, in FIGS. 8 to 13, the groove 66
．． 67, 69, and the filled glass 70 are partially omitted and shown by chain lines.

[Problem to be solved by the invention]

In the manufacturing process of the magnetic head as described above, especially in the R polishing process, conventionally, as shown in FIG. After fixing it, it is rotated back and forth around the center 0 (see arrow P).

Next, the head core block 61 is brought close to a grindstone Q serving as a polishing member and the head core block 61 is ground by the grindstone Q, thereby forming an R shape on the surface R of the head core block 61.

Therefore, during the R polishing process, the head core blocks 61 had to be attached to and removed from the jig one by one, resulting in a problem that the work was complicated and inefficient.

Also, since the head core block 61 rotates around the center 0, the distance between the center O and the polishing point S causes the polishing surface R to be
The radius and depth (Depth) 11 are determined dependently, and there is a problem in that it is impossible to adjust the dimensions of the surface shape and depth independently of each other.

Furthermore, there is a problem in that if the head core block 61 is machined differently, the surface shape will be different.

The present invention has been made to solve this problem, and an object of the present invention is to provide a method for manufacturing a magnetic head that can simultaneously polish a plurality of head core blocks into arbitrary shapes.

[Means to solve the problem]

In order to solve the above-mentioned problems, the present invention rotates a circular abrasive member whose outer peripheral end has a predetermined cross section, and attaches a longitudinally A head core block whose direction axis is directed in the direction of movement of the work table is removably attached, and the surface of the head core block is brought into contact with the outer peripheral end portion to be polished into the predetermined shape.

[Effect]

In the present invention, the outer peripheral end of the rotating circular polishing member is formed into a predetermined shape, and the head core block is polished by this end, so that the head core block is polished into a curved shape corresponding to the shape of the end. .

In addition, since the head core block moves forward and backward in the direction of movement of the outer peripheral end of the abrasive member, it is possible to arrange multiple abrasive members in parallel on the same axis, and multiple head core blocks are also arranged in parallel facing each abrasive member. can be set.

〔Example〕

As mentioned above, to manufacture a bulk type head, the 17th
As shown in Figures (a) and (b), track processing is performed on the core half 1a11b before the gap is formed, so when welding the core halves 1a and 1b to each other, track alignment requires high precision technology. must be done.

Therefore, a magnetic head manufactured by Sendust has been proposed that can omit the track alignment process that is necessary with the above-mentioned bulk type head (see FIGS. 16(a) and 16(b)). This magnetic head is called an all-track head (hereinafter referred to as an AT head) because its entire width is a track, and as shown in FIGS. 16(a) and (b), this AT head
The head has a pair of helad core halves 10a110b welded to each other, track width regulating grooves 12 forming tracks 11 are filled with glass 13, and this glass 13 is exposed on the tape sliding surface.

4(a) to 5(f) and FIG. 5 are diagrams showing a method of manufacturing the above-mentioned AT head. First, a pair of rod-shaped materials 6
A groove 62 for the winding and a groove 63 around the winding frame are formed on D to form the head core block half-open 61b, and a groove 64 around the winding frame is formed on the other material 61 to form the head core block half-open 61b.
1a (Fig. 4(a)). Next, the joint surfaces 65 of each head core block half body 61a, 61b are mirror polished,
Next, a gap spacer 68 is formed by electron beam evaporation of AIO, S t O2, etc. on the joint surface 65 of each head core block half 61a161b (
Figure 4(b)). Next, each head core block half 6
1a and 61b are welded with silver solder to form the head core block 66 (FIG. 4(c)), and then, by forming track grooves 69, tracks 101 are formed (FIG. 4(d)). . Thereafter, the track groove 69 is filled with glass 70 (FIG. 4(e)). Next, after R polishing is performed to form an R shape on the tape sliding surface 71, a sliding surface processing groove 102 is formed on the sliding surface 71 (FIG. 4(f)). Thereafter, the head core block is sliced at a predetermined angle in a direction crossing the longitudinal direction to obtain the Herad chips shown in FIGS. 16(a) and 16(b).

FIG. 5 is a perspective view showing how the head core block 21 is processed in order, and the head chip 41 is formed through the following steps: track processing C1 glass filling d, R polishing e1 sliding surface processing f1 slicing g. Manufactured.

The present invention relates to the R polishing process among the above-mentioned processes, and FIGS. 1(a) and 1(b) are views showing one embodiment of the present invention, and are front views of the polishing apparatus used in the present invention. 2(a) to 2(e) are explanatory diagrams showing the polishing process using the same device, and FIG. 2(a) is an enlarged view of the ■ part in FIG. 1(b). . In this embodiment, a blade (or grindstone) 121 having a concave arc-shaped outer circumferential tip is attached to a dicer (not shown) as a rotating circular abrasive member whose outer circumferential end has a predetermined cross-sectional shape. The blade 121 rotates as shown by arrow i around h and moves up and down as shown by arrow j. The head core block 21 is detachably attached to a work table 123 that moves forward and backward in the rotational movement direction of the outer peripheral end 122 of the blade 121 (direction perpendicular to the rotational axis of the blade 121, that is, the direction in the figure). . This block 2
1 has its longitudinal axis directed in the moving direction of the work table 123, and its surface is in contact with the outer peripheral end 122 of the blade 121 to form an R shape (curved surface shape, and this figure shows the case of a circular arc shape). polished). Note that during polishing, grinding water 124 is supplied to the contact portion.

Next, the operation will be explained. First, the head core block 21 is fixed to the work table 123, and the work table 123 is continuously moved forward and backward in the direction of the arrow. Meanwhile, the blade 121 is gradually lowered toward the work table 123 while being rotated in the direction of arrow i. Then, blade 12
The concave arc-shaped outer circumferential end 122 of the head core block 21 is polished while being in contact with the tape sliding surface 125 of the head core block 21 to remove unnecessary parts. (b) in the same figure), and polished to a predetermined depth ((c) in the same figure).

However, in FIGS. 1(a) and 1(b), the blade 121
and the head core block 21 on the work table 123 are shown in the figure, but normally, as shown in FIG.
All head core blocks 21 can be R-polished automatically by arranging them at a uniform pitch d, fixing them with wax, etc., attaching them to the stage of a dicer, and programming the feed of the stage and blade of the dicer. . In addition, if the blades are multi-blade in which the number of blades is stacked according to the number of head core blocks 21,
All Herad core blocks 21 can be processed at the same time, and processing efficiency can be further improved. Note that in the figure, the symbol θ is the azimuth angle.

Further, in this embodiment, since a dicer is used for grinding, the accuracy of grinding can be improved. Furthermore, the R shape is arbitrarily determined by the shape of the outer peripheral end 122, and the depth amount is determined by the moving distance of the blade 121 in the j direction, so it is possible to adjust the dimensions of the shape R and the depth amount independently of each other. becomes.

Note that the cross-sectional shape of the outer circumferential end portion 122 of the blade 121 is not limited to a simple circular arc shape, but can be made into any shape, and the range of application of R polishing can be significantly expanded.

By the way, although the above-mentioned embodiment shows the case of manufacturing an AT head, the present invention can be similarly applied to the case of manufacturing a bulk type head shown in FIGS. 6 to 15.

Further, the blade 121 is not limited to the plate shape as in the embodiment, but may have a plurality of grooves of a predetermined shape formed on the outer periphery of a cylindrical grindstone.

〔Effect of the invention〕

As explained above, the present invention rotates an abrasive member whose outer peripheral end has a predetermined shape, moves a work table back and forth in a direction orthogonal to the rotational axis of this abrasive member, and uses this outer peripheral end to form a head core. Since the blocks are polished, it is possible to line up multiple Herad core blocks in parallel on the work table and polish each one with high precision and efficiency.
The efficiency of polishing work can be improved.

[Brief explanation of drawings]

FIGS. 1(a) and 1(b) are a front view and a side view of a polishing apparatus showing an embodiment of the present invention, and FIGS. 2(a) to 2(c) are explanatory views showing the polishing process. 3 is a plan view showing the arrangement of the head core block in the present invention, and FIGS. 4 to 5
The figure shows a method of manufacturing an AT head to which the present invention can be applied, and FIGS. 4(a) to 4(f) show the order of manufacturing steps, and FIGS. Perspective view, same figure (
b) is a plan view, (d) to (f) are plan views, Fig. 5 is a perspective view showing the state in which the head core block is processed, and Figs. Figures 6 to 11 are perspective views, and Figure 12 (a) shows the manufacturing process in order.
), (b) are side views showing the glass filling procedure, FIGS. 13 to 15 are perspective views, FIGS. 16 (a) and (b) are a plan view and a front view of the AT head, respectively, and FIGS. Figure (a), (
b) is a plan view and a front view of a bulk type head, respectively, and FIG. 18 is an explanatory diagram showing a conventional polishing method. 21...Head core block, 121...Abrasive member (blade), 122...Outer peripheral end, 123...Work table. 122...Outer peripheral end 123...Work table Fig. Fig. d...Glass filling e...R grinding f...Sliding surface machining diagram Fig. 0 Fig. 1 Fig. 3 Figure 14 Figure 5 Figure 6 Figure a Figure 7

Claims (1)

[Claims] A head that rotates a circular abrasive member whose outer peripheral end has a predetermined cross section and whose longitudinal axis is directed in the direction of movement of the work table is attached to a work table that moves forward and backward in a direction orthogonal to the rotation axis of this abrasive member. A method of manufacturing a magnetic head, comprising: attaching a core block removably, and polishing the surface of the head core block into the predetermined shape by bringing the surface of the head core block into contact with the outer peripheral end.