JPH0411307A - Composite-type magnetic head and its production - Google Patents

Abstract

PURPOSE:To suppress sliding noise and to improve wearing resistance by providing wearing-resistant nonmagnetic parts on both sides in the track width direction of the magnetic gap and ferromagnetic metal thin films in a manner that these nonmagnetic parts expose large area facing to a magnetic recording medium. CONSTITUTION:Ferromagnetic metal thin films 2, 21 comprising amorphous Fe- or Co-alloy with an interposed magnetic gap 3 are provided on each face of a pair of main core halves 1, 11 comprising oxide ferrite. Track width regulating parts 4, 41 comprising glass are formed on both sides in the track width direction of the magnetic gap 3 and ferromagnetic metal thin films 2, 21. Moreover, nonmagnetic part 5, 51 such as Zn-ferrite,excellent in wearing resistance are provided on both sides of the main core halves 1, 11 and track width regulating parts 4, 41 in a manner that nonmagnetic parts 5, 51 expose large area facing to a magnetic recording medium. Thereby, sliding noise is reduced and wearing resistance in the nonmagnetic parts is improved.

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention relates to a magnetic head installed in a magnetic recording/reproducing device such as an 8mm VTR or a digital audio tape recorder (R-DAT), and particularly relates to a magnetic This invention relates to a composite magnetic head in which a ferromagnetic metal thin film is formed opposite to a gap.

(Prior Art) So-called ferrite heads, in which the magnetic circuit is formed only from ferrite cores, have been widely used in home VTRs, but in order to improve recording performance in the low frequency range, the head shown in FIG. As shown in the figure, a pair of main core halves (101 and 102) are formed of a metallic magnetic material with high saturation magnetic flux density, and a magnetic gap part (
A magnetic head has been proposed in which a pair of non-magnetic substrates (104) and (105) are fixed on both sides of the amphibious core halves (101 and 102).
No. 3909 [G11B5/187)). Since the magnetic circuit of the magnetic head is formed only of the main cores (101) and (102), it has a drawback of high magnetic resistance.

On the other hand, as shown in FIGS. 16 and 17, M n
-A pair of main core halves (105) made of Zn single crystal
(106), a pair of ferromagnetic metal thin films (
A so-called composite magnetic head has been proposed in which a magnetic head of 10'/) (108) is formed (for example, Japanese Patent Laid-Open No. 172203/1988 (G11B5/187)).

This kind of composite magnetic head has a ferromagnetic metal thin film (107) (
108) has a high saturation magnetic flux density, and the main core half (1
05) and (106) are formed from a ferrite single crystal with low eddy current loss in a high frequency band, they have excellent not only recording performance but also reproduction performance, and have sufficient wear resistance.

Furthermore, as shown in FIG. 15, on both sides of the magnetic gap portion (3) and the ferromagnetic metal thin films (107) (103) in the track width direction, dog-like areas are provided on the surface (100) in contact with the magnetic recording medium. A composite magnetic head with an exposed glass portion (109) (NO) has been proposed (Japanese Patent Laid-Open No. 62-24
No. 4'15 [G11B5/255]). The glass part (
109) As the material in (110), low melting point glass is used from the viewpoint of the working temperature of glass welding in the manufacturing process of the magnetic head.

(Problem to be Solved) However, in the composite magnetic head shown in FIGS. 16 and 17, since the ferrite core is largely exposed on the surface (100) that faces the magnetic recording medium, so-called sliding movement occurs. There was a big problem with noise.

On the other hand, in the composite magnetic head shown in FIG. 15, the area of the ferrite core exposed on the contact surface (100) is smaller than that in the magnetic heads shown in FIGS. 16 and 17, so there is no sliding noise. can be reduced, but the low melting point glass part (10
9) The formation of (110) conversely reduces the wear resistance of the contact surface (100), resulting in a problem of shortening the life of the magnetic head.

SUMMARY OF THE INVENTION An object of the present invention is to provide a structure of a composite magnetic head that can suppress the generation of sliding noise and also has excellent wear resistance, and a method for manufacturing the same.

(Means for Solving the Problems) In the composite magnetic head according to the present invention, as shown in FIG.
) (21) on both sides of the track width direction, main core halves (1
) (11), non-magnetic parts (5) (51) having wear resistance equivalent to or higher than that of (11) are provided, and the non-magnetic parts (5)
The surface of (51) is exposed to the contact surface (14) with the magnetic recording medium in a dog-like area.

Further, the method for manufacturing a composite magnetic head according to the present invention includes a first method for manufacturing a composite magnetic head.
In the process (Fig. 3), a ferromagnetic metal thin film (22) is formed on the surfaces of a pair of substrates (12) and (13) that will become the main core halves, and the thin film formation on these ferrite substrates (12) and (13) is performed. A lower half block (74) is fabricated by integrally joining the surfaces with each other via the gap spacer (31).

In the next second step (Fig. 4(a), (b), and (c)), 7-shaped grooves (75) are formed at a constant pitch on the surface of the block (74) that is substantially perpendicular to the thin film formation surface. Recessed.

Thereafter, in a third step (FIG. 5), protrusions (53) having a chevron-shaped cross section that can be substantially tightly engaged with the mating grooves (75) of the lower half block (74) are formed at a constant pitch. A non-magnetic material (52) is fixed onto the grooved surface of the lower half block (74) via a bonding layer.

In the fourth step (FIG. 6), curved surface polishing is performed on the surface of the non-magnetic material (52) side of the head block (77) obtained through the third step, and the gap spacer ( 31) and the ferromagnetic metal thin film (22) (22) forms an exposed surface (76) facing the recording medium.

Furthermore, in a fifth step, the head block (77) that has undergone the fourth step is coated with a non-magnetic material (
The surface of the non-magnetic material (52) is cut along the cutting line passing through the gap spacer (31) and the ferromagnetic metal thin film (2).
2) A magnetic head chip with a large area exposed on both sides in the track width direction is manufactured.

(Function) In the above-described method for manufacturing a composite magnetic head, the first step can be configured by a well-known vacuum thin film forming technique or the like. Grooving in the next second step can be easily performed using a rotary grindstone or the like. Furthermore, so-called glass bonding can be used to bond the lower half block (74) and the non-magnetic material (52) in the third step. Furthermore, in the fourth step, by applying curved polishing to the surface of the head block (77) on the non-magnetic material (52) side, the non-magnetic material (52) forms a diamond shape on the polished surface as shown in FIG. appears at a constant pitch, and
A gap spacer (3) is placed between these non-magnetic materials (52).
1) and ferromagnetic metal thin films (22) (22) appear, and a surface (76) facing the magnetic recording medium is formed.

The magnetic head chip obtained through the subsequent fifth step is
The non-magnetic materials (52) (52) shown in Figure 6 become the non-magnetic parts (5) (51) in Figure 1, and the gap spacer (31)
), a magnetic gap portion (3) is formed.

(Effects of the Invention) In the composite magnetic head according to the present invention, the magnetic gap portion (3) and the ferromagnetic metal thin films (2) and (21) are provided on both sides of the magnetic gap portion (3) and the ferromagnetic metal thin films (2) and (21) on the surface (14) in contact with the magnetic recording medium. Non-magnetic part (
5) Since (51) is largely exposed, the main core half (
1) Sliding noise is reduced by reducing the exposed area of (11), and the life of the magnetic head is also improved due to the excellent wear resistance of the non-magnetic parts (5) and (51).

Further, according to the method for manufacturing a composite magnetic head according to the present invention, the composite magnetic head can be easily manufactured through the simple steps described above.

(Examples) Examples are provided to explain the present invention, and should not be construed as limiting the invention described in the claims or reducing its scope.

As shown in FIG. 1, FIG. 1(a), and FIG. 2, the composite magnetic head according to the present invention includes a pair of main core halves (1) and (11) made of oxide ferrite at the abutting portions. On both sides of the magnetic gap part (3), sendust, permalloy, F
Ferromagnetic metal thin films (2) (21) made of e or Co-based amorphous alloy are provided, and the magnetic gap portion (
3) and on both sides of the ferromagnetic metal thin films (2) and (21) in the track width direction, there are glass track width regulating parts (4) and (4).
1). Further, on both sides of the amphibious core halves (1) (11) and the track width regulating portions (4) (41), Zn is coated.
- Non-magnetic part with excellent wear resistance such as ferrite (5) (5
1), and the surfaces of the non-magnetic parts (5) and (51) are exposed over a large area to the surface (14) in contact with the magnetic recording medium.

Hereinafter, a method for manufacturing the above-mentioned composite magnetic head will be explained.

First, a laminated block (7) shown in FIG. 3 is produced.

The laminated block (7) is made by forming a ferromagnetic metal thin film (22) to a predetermined thickness on the surfaces of a pair of substrates (12) and (13), which form the main core halves, by a method such as sputtering, vapor deposition, or plating. The thin film forming surfaces of these ferrite substrates (12) and (13) are integrally bonded to each other via a gap spacer (31). Each board (12) (13
Track width regulating grooves (71) are recessed at a constant pitch on the thin film forming surface of each of the grooves (71). Further, the track width regulating groove (
A coil groove (72) and a glass groove (73) are recessed in a direction intersecting with the coil groove (71). Side board (12) (13)
As is well known, the welding process is carried out by inserting a glass rod for welding into the glass groove (73) and heating and melting the glass rod in an inert atmosphere. Along with this, the track width regulating groove (71) is also filled with glass. In addition, as a welded glass, for example, the softening point is 5.
Glass having a temperature of 70° C. and a Vickers hardness of about 350 can be used.

The laminated block (7) thus obtained is cut along the chain line in the figure for each coil groove (72) to cut out a plurality of lower half blocks (74).

Next, as shown in FIGS. 4(a), (b), and (c), the cut surface of the lower half block (74) is cut into a 7-shaped groove (75) using, for example, a rotary grindstone (9). are recessed at a constant pitch. At this time, the groove machining is performed so that the ridgeline of the mountain on the serrated cross-sectional surface thus formed coincides with the line that approximately bisects the ferromagnetic metal thin film (22) (22), as shown in Figure (a). It is done.

In addition, in parallel with the above process, a non-magnetic material (52
). The non-magnetic outer material (52) is provided with protrusions (53) having a chevron-shaped cross section that can be substantially tightly engaged with the mating grooves (75) of the lower half block (74) at a constant pitch. As the non-magnetic material (52), a highly hard non-magnetic material that does not undergo thermal deformation at about 800° C., such as Zn-ferrite having a Vickers hardness of about 500, is used. The Vickers hardness of the non-magnetic material (52) is preferably 400 or more in order to maintain the wear resistance of the magnetic head.

A glass rod (
8), the non-magnetic material (52) is further placed on top of the non-magnetic material (52), and the glass rod (8) is heated and melted in a vacuum atmosphere to form the non-magnetic material (52) and the lower half block ( 74) are joined and integrated in a crimped state. As the glass rod (8),
It is possible to use a material having a softening point comparable to or lower than that of the welded glass, for example, a material having a softening point of 540° C. and a Vickers height of about 340.

As shown in FIG. 7, if the angle θ of the peaks of the sawtooth cross section of the lower half block (74) and the non-magnetic material (52) is smaller than 60 degrees, the workability of the groove will deteriorate; If the angle is larger than 120 degrees, the exposed area of the main core halves (1) and (11) on the contact surface (14) shown in FIG. 2 becomes large, so a range of 60 degrees≦θ≦120 degrees is desirable.

In addition, as shown in FIG. 7, the tips of the peaks of the non-magnetic material (52) are formed to be slightly rounded, and the cross-sectional area S of the glass rod (8) is
The ratio between the cross-sectional area S2 of the peak of the lower half block (74) and the cross-sectional area S of the peak of the non-magnetic part (51) is Sl: Ss:
It is preferable to design the ratio Ss#20:90:100 in order to make the non-magnetic material (52) and the lower half block (74) come into close contact with each other without any gaps.

Furthermore, if the pressing force between the non-magnetic material (52) and the lower half block (74) is too small, the glass will not penetrate into the gap sufficiently, and if it is too large, the lower half block (74) will crack. Therefore, approximately 2 kg/cm2 is desirable.

After that, the head block (77
) on the non-magnetic material (52) side as shown in FIG.
The ferromagnetic metal thin film (22) (22) forms an exposed surface (76) facing the recording medium.

Furthermore, the head block (77) that has gone through the above steps is cut along a cutting line passing through the non-magnetic material (52) exposed on the contact surface (76) to complete the magnetic head chip shown in FIG. In the magnetic head chip, a part of the glass portion (42) shown in FIG. 4(a) is the track width regulating portion (4) shown in FIG.
(41), and a part of the non-magnetic material (52) in FIG. 5 becomes the non-magnetic portion (5) (51) in FIG.

FIGS. 8 to 11 show the shapes of various parts appearing on the contact surfaces of various composite magnetic heads manufactured through the same steps as described above.

The track width A of the magnetic head in Fig. 8 is 27 μm, the total width B of both track width regulating portions (4) and (41) is 29 μm, the width C of the main core halves (1) and (11) is 210 μm, and the length D is 2
400 μm, and the radius of curvature of the opposing surface (14) is 8
mm, and θ in FIG. 7 is 90 degrees.

The track width E of the magnetic head in Fig. 9 is 27 μm, the width F of both track width regulating portions (4) and (41) is 29 μm, the maximum width G of the main core halves (1) and (11) is 134 μm, and both non-magnetic portions. (5) The total width H of (51) is 210 μm, and the length ■ is 24
00 μm, and the radius of curvature of the opposing surface (14) is 8 m
m, and θ in FIG. 7 is 60 degrees.

Also, the track width J of the magnetic head shown in FIG. 10 is 27μ.
The width of the m1 track width regulation part (4) (41) is 29μ.
m, the width of the main core halves (1) (11) is 210 μm.

The length M of the non-magnetic part (5) (51) is 1826 μm, the total length N of the amphibious core halves (1) (11) is 2400 μm, and the radius of curvature of the contact surface (14) is 8 mm. θ of
is 120 degrees.

Furthermore, the track width 0 of the magnetic head shown in FIG. 11 is 20.
μm1 Width P of both track width regulating parts (4) (41) is 22
μm, and the width Q of the main core halves (1) and (11) is 135 μm.

The length R is 1500 μm, the radius of curvature of the contact surface (14) is 5 mm, and θ in FIG. 7 is 90 degrees.

The magnetic heads shown in FIGS. 8 to 10 are for long-time recording and reproducing mode of VH8 system, and the magnetic head shown in FIG. 11 is for R-DA.
It is provided for T.

FIG. 12 is a graph showing the results of a wear resistance test conducted on the composite magnetic head according to the present invention shown in FIG. The test was conducted at a temperature of 25°C, which is the temperature at which the head is likely to wear out.
The test was carried out in an atmosphere of 60% humidity by setting a 5-VHS tape cassette on a 5-VHS VTR deck. As is clear from FIG. 12, the amount of decrease in gap depth over time of the composite magnetic head according to the present invention is much smaller than that of the magnetic head shown in FIG. 14, and is equivalent to that of the ferrite head. Abrasion resistance is achieved.

Moreover, when the contact surface (14) of the magnetic head of the present invention was observed after the test, it was found that the non-magnetic parts (5) (51) and the main core half (
No problematic uneven wear was observed between 1) and (11).

FIG. 13 is a graph showing the results of a test conducted regarding the generation of sliding noise. The test was conducted by recording a 5 MHz single sine wave signal after aging for 24 hours in an atmosphere with a temperature of 20°C and a humidity of 20% where sliding noise is likely to occur.
This study investigated changes in the noise level in the reproduced spectrum.

The curve (91) in Fig. 5 is the ferrite head, and the curve (92)
) is the composite magnetic head of the present invention, and curve (93) is the 14th magnetic head.
The noise curve (94) for the magnetic head in the figure shows system noise. As is clear from the figure, the noise level of the composite magnetic head according to the present invention is significantly reduced compared to the conventional ferrite head, and is suppressed to a low level equivalent to that of the magnetic head shown in Fig. 14. .

As described above, the composite magnetic head according to the present invention has low sliding noise, can obtain high output over a wide range from high frequency to low frequency, and exhibits excellent wear resistance.

The above description of the embodiments is for illustrating the present invention, and should not be construed to limit or reduce the scope of the invention described in the claims.

Further, it goes without saying that the configuration of each part of the present invention is not limited to the above-mentioned embodiments, and various modifications can be made within the technical scope of the claims.

For example, the ferromagnetic metal thin film (2) appearing on the opposing surface (14)
) (21) can also be shaped to extend obliquely to the track width direction, as shown in FIG. 16 or 17.

[Brief explanation of the drawing]

FIG. 1 is a perspective view of a composite magnetic head according to the present invention;
Figure (a) is a side view of the composite magnetic head, Figure 2 is a plan view of the composite magnetic head, Figure 3 is a perspective view of the laminated block, and Figures 4 (a), (b), and (c) are Fig. 5 is a perspective view of the non-magnetic part and the lower half block, Fig. 6 is a perspective view of the head block, and Fig. 7 is the non-magnetic material and the lower half block. 8 to 11 are plan views of various composite magnetic heads embodying the present invention, FIG. 12 is a graph showing the wear resistance test results, and FIG. 13 is a cross-sectional view explaining the bonding process. Graphs showing test results regarding sliding noise, and FIGS. 14 to 17 are perspective views of conventional magnetic heads, respectively. (1) (11)...Main core half (2) (21)...Ferromagnetic metal thin film (3)...Magnetic gap part (4) (41)...Track width regulating part (5 )(51)
...Non-magnetic part (MHz) Figure 1a Broom 14 Figure 15 Procedure correction command formula) % formula % Display of case 1990 Patent Application No. 112724 2゜ Title of invention Composite magnetic head and method for manufacturing the same 3゜Relationship with the case of the person making the amendment

Claims (1)

[Claims] [1] At the abutting portion of the pair of main core halves (1) and (11),
In a composite magnetic head in which ferromagnetic metal thin films (2) (21) are provided on both sides or one side of a magnetic gap part (3), the magnetic gap part (3) and the ferromagnetic metal thin films (2) (21) On both sides in the track width direction, non-magnetic parts (5) (51) having wear resistance comparable to or higher than that of the main core halves (1) (11) are provided. ) (51) is the surface facing the magnetic recording medium (14).
) is a composite magnetic head that is characterized by a large exposed area. [2] At the butt part of the pair of main core halves (1) (11),
In a method for manufacturing a composite magnetic head in which ferromagnetic metal thin films (2) (21) are provided on both sides or one side of a magnetic gap (3), a pair of substrates (12) ( A lower half block (13) is formed by forming a ferromagnetic metal thin film (22) on the surface of the ferrite substrate (12) and integrating the thin film-forming surfaces of the ferrite substrates (12) and (13) with each other via a gap spacer (31). 74), and a second step of forming V-shaped grooves (75) at a constant pitch on the surface of the block (74) that is substantially orthogonal to the thin film formation surface.
A non-magnetic material (52) having protrusions (53) having a chevron-shaped cross section that can be substantially tightly engaged with each groove (75) of the lower half block (74) is formed at a constant pitch. half block (74
) on the groove-formed surface of the head block (77) via a bonding layer, and curved surface polishing is performed on the surface of the non-magnetic material (52) side of the head block (77) obtained through the above steps. The gap spacer (31) and the ferromagnetic metal thin film (
22) (22) is exposed on the surface facing the recording medium (76)
A fourth step of forming the head block (77) through the step is cut along a cutting line passing through the non-magnetic material (52) exposed on the opposing surface (76), and the non-magnetic material (52) The surface of the gap spacer (
31) and a fifth step of manufacturing a magnetic head chip with a large area exposed on both sides of the ferromagnetic metal thin film (22) in the track width direction.