JPH02130708A - Composite type magnetic head - Google Patents

Abstract

PURPOSE:To suppress occurrence of sliding noise by extending both end sections of ferromagnetic metallic layers in directions in which the metallic layers are separated from a magnetic gap section into core half bodies after passing through the boundaries between a glass section and the core half bodies. CONSTITUTION:A pair of ferromagnetic metallic layers 2 and 21 of 'Sendust(R)' etc., are formed at the butting section of a pair of magnetic core half bodies 1 and 11 of a ferromagnetic oxide of Mn-Zn ferrite, etc., with a magnetic gap section 3 of SiO in between. The metallic layers 2 and 21 have a surface shape of Z as a whole on the surface 10 which is brought into contact with a magnetic tape and extended in directions in which the layers 2 and 21 are separated from the magnetic gap section 3 in a plane which is inclined by about 45 deg. against the joined surface of both core half bodies 1 and 11. In addition, both end sections A and A of the layers 2 and 21 enter the core half bodies 1 and 11 are turned to the core joining surface side at the end sections A and A and are extended to the core joined surface. Moreover, at the joining section of the core half bodies 1 and 11, high-melting point glass sections 4 and 41 and low-melting point glass sections 5 and 51 are respectively provided on the entire area of the magnetic gap section 3 and most of the ferromagnetic metallic layers 2 and 21. The low-melting point glass sections 5 and 51 are extended to the depth position of a coil window 6 from the surface 10 contacted with a tape.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a magnetic head in which a magnetic circuit near a magnetic gap portion is formed of a ferromagnetic metal thin film.

(Prior Art) In recent years, in magnetic recording and reproducing devices such as VTRs, the density and frequency of recording signals have been increasing, and along with this, ferromagnetic metals such as Fe, Co, and Ni have been used as magnetic powder. Coating-type metal tapes using powder and having high coercive force, or vapor-deposited tapes in which a ferromagnetic metal material is deposited on a base film by vapor-deposition, and the like are increasingly being used. In order to record signals on this type of magnetic tape, a magnetic head made of a magnetic material having a high saturation magnetic flux density is required.

Therefore, as shown in FIG. 6, conventionally a pair of magnetic core halves (1) (11) made of ferromagnetic oxide such as ferrite,
A composite magnetic head has been proposed in which ferromagnetic metal layers (24) (25), such as sendust, are formed between the abutting portions with a magnetic gap portion (3) in between (JP-A-61-2
87018 [C11BS/23]).

In the magnetic head, ferromagnetic metal layers (24) (25)
) and the ferromagnetic metal layer forming surfaces of the core halves (1) and (11) are provided non-parallel to each other, and glass portions (46) (46) are provided on both sides of the magnetic gap portion (3).
This prevents the occurrence of so-called pseudo gaps and limits the actual track width to a predetermined value.

A method of manufacturing the above magnetic head is shown in 7th m<a> to (g).

First, as shown in FIG. 7(a), a thin film formation groove (14) with an inclined bottom surface is formed in the surface of the magnetic substrate (12), and then
As in b), a ferromagnetic metal film (22) is formed by sputtering on the groove forming surface of the magnetic substrate (12).

Next, as shown in the same figure (e), a ferromagnetic metal Ill! (22)
After filling the surface of the substrate (12) with glass (47), the surface is polished, and as shown in FIG. expose it.

Furthermore, as shown in FIG. 7(e), on the surface of the magnetic substrate (12),
A track width regulating groove (16) is recessed along the filling portion.

As shown in FIG. 7(f), among the pair of block halves (74) and (75) produced through the above steps, one block half (74) has a coil groove (61) and a welding groove. (62)
After recessing both block halves (74) and (75),
overlaid on each other via iOzNI <not shown),
Furthermore, by melting the glass rod (48) inserted into the welding groove (62) in the heating furnace, the two block halves (74) and (75) are glass-bonded as shown in the same figure (Fl) to form the core. A block (70) is produced.

Finally, the magnetic head shown in FIG. 6 is completed by slicing the core block (70) and polishing the tape-contacting surface into a curved surface.

(Problem to be Solved) However, in the magnetic head shown in FIG.
〉 core halves (1) (11
) acts as a magnet on the magnetic tape, which causes sliding noise.

Furthermore, in manufacturing the magnetic head, the machining accuracy of the track width regulating groove (16) shown in FIG. 7(e) influences the accuracy of the final track width of the magnetic gap, so High precision is required for processing, which poses the problem of significantly increasing the number of man-hours.

However, as shown in FIG. 7(b), a ferromagnetic metal film (22) having a coefficient of thermal expansion significantly different from that of the magnetic substrate (12) is formed on the entire surface of the magnetic substrate (12). In the glass bonding process shown in f), excessive internal stress occurs in the surface layer of the ferromagnetic metal M (22) and the magnetic substrate (12), which causes the ferromagnetic metal M (22) to! 1lllllI! There is a problem that cracks occur in the magnetic substrate (12) and the yield decreases.

An object of the present invention is to provide a magnetic head having a structure that can suppress the occurrence of sliding noise as much as possible, and can be manufactured with fewer man-hours than conventional ones and with a high yield.

(Means for Solving the Problems) A magnetic head according to the present invention has a magnetic gap portion (3) sandwiched between the abutting portions of a pair of magnetic core halves (1) and (11) made of ferromagnetic oxide. A pair of ferromagnetic metal layers (2) (21
) is deployed. The ferromagnetic metal layers (2) (21) are
It is formed on a flat or curved surface that is non-parallel to the magnetic gap forming surface.

At the abutting portion of the core halves (1) (11), a glass portion <4) <41) ( 5) <5
1) is provided.

Moreover, the magnetic gap portion (3) of the ferromagnetic metal layer (2) (21)
) (A, A in Fig. 2) penetrate the interface between the glass part <4> (41) (,5) (51) and the core half <1) (11). Core half # (1) (1
1) Extending inward.

(Function) The ferromagnetic metal layer (2) that has penetrated into the core halves (1) (11)
)〈21), the core half (1) (
11) and the ferromagnetic metal layer (2>(21)) are magnetically connected to each other to form a magnetic loop with a magnetic gap (3) interposed therebetween.

(Effects of the Invention) In the composite magnetic head according to the present invention, the glass portions (4) (41) surround the entire periphery of the magnetic gap portion (3).
(5) and (51) are formed, and between the magnetic gap part (3) and the core halves (1) and (11) on the surface 10) that faces the magnetic recording medium, Since there is a sufficient distance, sliding noise as in the conventional case does not occur, and most of the ferromagnetic metal layers (2) (21) are glass parts (
4) Surrounded by (41) (5) (51), the contact area between the ferromagnetic metal layer (2) (21) and the core half body (1) (11) is narrower than in conventional magnetic heads. Correspondingly, in the manufacturing process of the magnetic head, the core half (
1) <2) Magnetic substrate (12) and ferromagnetic metal 1 (2) (21) ferromagnetic metal III (22)
The contact area with the magnetic head is narrower than in the case of conventional magnetic heads (see Figures 4(e) and (f)). Therefore, when glass-bonding a pair of block halves (see Figure 4(i)) j)), defects due to thermal stress do not occur, and the yield is improved compared to conventional magnetic heads.

However, since the track width of the magnetic gap portion (3) is defined by the film thickness of the ferromagnetic metal layer (2>(21)), there is no need for track width regulating grooves as in conventional magnetic heads. Therefore, the number of man-hours required to manufacture the magnetic head can be reduced compared to the conventional method.

(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.

FIGS. 1 and 2 show an example of a composite magnetic head according to the present invention.

A pair of magnetic core halves (1) and (11) made of a ferromagnetic oxide such as Mn-Zn ferrite are sandwiched between a magnetic gap part (3) made of Sio2 at the abutting part, and a magnetic core made of sendust or an amorphous alloy is placed between them. A pair of ferromagnetic metal layers (2)
(21) is formed.

The ferromagnetic metal layer (2) (21) has a tape contact surface (10
) has a two-character shape, and both core halves (1
) (11) extends in a direction away from the magnetic gap part (3) on a plane inclined approximately 45 degrees with respect to the bonding surface of (11), and both ends A
, A penetrate into the core halves (1) and (11), and further fold back from the end A toward the core joint surface and extend to the core joint surface.

Further, at the abutting portion of the core halves (1) (11), a high melting point glass portion (4) surrounds the entire magnetic gap portion (3) and most of the ferromagnetic metal layers (2) (21). (41) and low melting point glass parts (5) and (51) are provided. The glass portion extends from the tape contact surface (10) to the depth of the coil window (6).

As will be described later, the high melting point glass portions (4) (41) and the low melting point glass portions (5) (51) have thermal expansion coefficients similar to those of the core half (
1) It is formed from a glass material larger than the ferromagnetic oxide of (11) and smaller than the ferromagnetic metal layers (2) and (21).

The method for manufacturing the above magnetic head will be described below.9 First, a magnetic substrate (12) shown in FIG. Glass filled? II (13) is repeatedly recessed using a rotary grindstone or the like.

Next, as shown in FIG. 4(c), a high melting point glass film with a softening point of about 650°C and an expansion coefficient of about 140 x 10-7 m/'C at a temperature of 0 to 300°C is applied to the groove forming surface of the magnetic substrate (12). (42)
form. The high melting point glass film (42) is formed, for example, by the method shown in FIGS. 5(a) and 5(b). That is, as shown in FIG. 5(a), a magnetic substrate (12) is placed between a pair of pressing jigs (100) and (101) made of quartz glass.
, glass plate (4) that is the material for high melting point glass M (42)
4), and metal foil (102), and press the glass plate (44) onto the magnetic substrate (1) using both pressure jigs as shown in FIG.
2) The glass plate (44) is heated in a heating furnace under pressure.
It melts it.

Thereafter, as shown in FIG. 4(d), the glass-filled surface of the magnetic substrate (12) is polished to expose the groove (13) filled with the high melting point glass (43).

A glass-filled groove (1) is formed on the polished surface as shown in FIG.
A thin film forming groove (14) substantially perpendicular to 3) is recessed to a depth greater than that of the glass filling groove (13). The bottom surface of the thin film forming groove (14) is formed into a flat surface inclined to the polishing surface (for example, a 45 degree slope) or a curved surface.

As shown in FIG. 4(f), a ferromagnetic metal film (22) made of Sendust or an amorphous alloy is formed on the groove forming surface of the magnetic substrate (12) by sputtering to a predetermined thickness corresponding to the track width. do.

As shown in FIG. 4(g), a low melting point glass film with a softening point of approximately 400°C and an expansion coefficient of approximately 140X 10-'C at a temperature of approximately 400°C and an expansion coefficient of 0 to 300°C is placed on the surface of the ferromagnetic metal film (22) as shown in FIG. 4(g). (52
) to form. A method similar to that shown in FIG. 5 can be used to form the low melting point glass film (52).

Furthermore, as shown in FIG. 4(h), the low melting point glass film (5
Surface grinding is applied to the forming surface of Z), and ferromagnetic metal <23)
, a block half (71) having a low melting point glass (53) and a high melting point glass (43) exposed on the surface is produced.

A pair of block halves (71) obtained through the above steps
Figure 4 (
As shown in i), seven coil holes (61) are provided along the filling groove of the high melting point glass (43).

Thereafter, as shown in FIG. 4(j), the pair of block halves (1) (72) are coated with a nonmagnetic layer (31) of SiO2.
The layers of ferromagnetic metal (23) are joined to each other in an abutting phase, and the low melting point glass (53) is melted in a heating furnace. As a result, both blocks (71) are cut in half (72)
) are fixed together to obtain an integral core block (7).

The core block (7) is cut along the X-ray in the figure to produce a head block (8) shown in FIG. 4(k). Furthermore, the head block (8) is sliced along the Y line in the figure, and the surface facing the magnetic tape is polished to a curved surface, thereby completing the magnetic head shown in FIG. 1.

High melting point glass part (4) (41) and low melting point glass part (5
The composition and physical properties of ) (51) are shown in the coating below.

In addition, as shown in FIGS. 3(a) and 3(b), the tape contact surface (1
By applying grooves (9) and (91) to 0), the area other than the magnetic gap part (3), that is, the ferromagnetic metal layer <2)
Completely eliminate magnetic flux leakage in the part (B in Figure 2) where (21) and core halves (1) and (11) face each other at a short distance with the high melting point glass parts (4) and (41) in between. It can be prevented.

In the magnetic head shown in FIG.
0), magnetic gap part (3) and core half (1) (1
1) are sufficiently spaced apart from each other, so there is no sliding noise as in the conventional case.

Furthermore, in the process of forming the ferromagnetic metal film (22) shown in FIG. Magnetic substrate (
12) The contact area with the magnetic head is halved compared to that of conventional magnetic heads. Therefore, in the glass bonding process shown in Figure (j), the internal stress generated between the magnetic substrate (12) and the ferromagnetic metal film (22) due to the difference in thermal expansion coefficients is smaller than that in the past. Also, as mentioned above, the thermal expansion coefficients of the low melting point glass and the high melting point glass are larger than that of the magnetic substrate (12) and smaller than that of the ferromagnetic metal film (22), so the internal stress is alleviated by the glass portion. It turns out.

Therefore, when polishing the surface of the block half (71) as shown in FIG. 4(h), or when bonding the pair of block halves (71) and (72) with glass as shown in FIG. 4(U), strong No peeling of the magnetic metal layer or cracking of the magnetic substrate occurs.

However, as shown in Figure 2, on both sides of the magnetic gap part (3),
Low melting point glass part (5) (51) and high melting point glass part (4
) (41) are provided, and the track width is defined by these glass parts, so that from FIG. 4(h) to FIG. 4(j>
In the manufacturing process leading up to this step, the conventional processing of track width regulating grooves (FIG. 7(e)) is unnecessary. Incidentally, in the magnetic head of the present invention, it is necessary to process the glass-filled groove (13) shown in FIG. High accuracy is not required. Therefore, the number of man-hours required to manufacture the magnetic head of the present invention is reduced compared to conventional magnetic heads.

The drawings and the description of the above-mentioned embodiments are for explaining the present invention, and the drawings and the explanation of the above-mentioned embodiments are not intended to limit or reduce the scope of the invention described in the claims. It should not be understood.

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.

[Brief explanation of the drawing]

FIG. 1 is a perspective view of a magnetic head according to the present invention, FIG. 2 is a plan view of the same as above, FIG. 3(a) is a plan view of a magnetic head showing another embodiment, and FIG. 3(b) is a plan view of the same. Figure (a) is a sectional view taken along line B-B, Figures 4 (,) to (k> are perspective views showing the magnetic head manufacturing process in Figure 1, Figure 5 is a diagram explaining the glass filling process, Figure 5 is a diagram illustrating the glass filling process, Figure 6 is an oblique view of a conventional magnetic head, and Figure 7 (
, ) to (g) are perspective views showing the manufacturing process of the magnetic head of FIG. 6. (1) (11) ... Core half (2) (21) ... Ferromagnetic metal layer (3) ... Magnetic gap part (4) (41) ... High melting point glass part (5) (51) ...Low melting point glass section Figure 5 Procedural amendment (voluntary) 1゜Indication of case 2, Title of invention Patent application 1986-285309 Composite magnetic spatula Sanyo Electric Co., Ltd. 5, Subject of amendment 4I Detailed Description of the Invention Column 6, Contents of Amendment <1> Page 9 of the Specification, Line 18, "Approximately 140 x 10"'m/'C~ Formation" (2) Page 9 of the Specification, Line 19 "Formation of high melting point glass WA (42) in line r" is corrected to filling 1 of high melting point glass (42) in r high melting point glass (42). 42) J is corrected to c high melting point glass (42) J. (4) Specification, page 11, lines 2 to 3, “approximately 14
0x10-'輔/℃〜Formation' is approximately 140xlO-
'/'C low melting point glass (52) is formed. Correct to 1 for filling with low melting point glass (52). (5) Specification, page 11, lines 5 to 6 "Low melting point glass film (52) J is corrected to r low melting point glass (52) J. (6) Specification, page 11, line 6 ~7th line "Ferromagnetic metal (23) J is corrected to 7 ferromagnetic metal film (23) J. (7) Specification page 11, line 15 "Phase" is corrected to r position 1. (8) r(0~300℃)(m/'C)J in the table on page 12, line 15 of the specification
Corrected to 00℃)(/”C)J.

Claims (1)

[Claims] [1] A pair of magnetic core halves made of ferromagnetic oxide (1)
A pair of ferromagnetic metal layers (2) and (21) are provided at the abutting portion of (11) with the magnetic gap portion (3) in between, and the ferromagnetic metal layers (2 and 21) form the magnetic gap portion. In a composite magnetic head formed on a flat or curved surface that is non-parallel to the surface, the abutting portion of the core halves (1) and (11) includes the entire magnetic gap portion (3) and the ferromagnetic Metal layer (2)
Glass portion (4) (41) surrounding most of (21)
(5) (51) are provided, and the ferromagnetic metal layer (2) (21
) of the glass portion (4) (41) (5) (51) and the core half (
1) (11) through the interface with the core half (1) (11)
) A composite magnetic head characterized by an inward extension.