JPS61214203A - Production of magnetic head - Google Patents

Abstract

PURPOSE:To reduce the thickness in the head height direction of a nonmagnetic material part by packing and welding a nonmagnetic material in a nonmagnetic material groove and finishing block half bodies until the nonmagnetic material is exposed on the center part of the joint surface when a pair of block half bodies are joined. CONSTITUTION:After a pair of block half bodies 20 and 21 consisting of magnetic materials are formed, a coil groove 42 to be a coil window 4 is provided in one block half body 20. A pair of nonmagnetic material grooves 40 and 41 extended along the coil groove 42 are provided approximately vertically to joint surfaces 24 and 25 on joint surfaces 24 and 25 of both block half bodies 20 and 21. When both block half bodies 20 and 21 are joined, the nonmagnetic material is packed in nonmagnetic material grooves 40 and 41 and is welded to form a joined block. Finally, the block is machined to produce a reinforcing core 2 having the coil window 4 and a nonmagnetic material part 3. Reinforcing cores 2 are joined to a main core 1 to produce a head chip body 9, and the head chip body 9 is polished up to the position indicated by a broken line to complete a magnetic head. Thus, the productivity is improved, and the thickness of the nonmagnetic material 3 is reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a method of manufacturing a magnetic head used in a magnetic recording/reproducing device such as a VTR.

(Prior Art) In an 8mm/1J VTR, a magnetic head using a high saturation magnetic flux density material such as a sendust alloy or an amorphous magnetic material is used in order to perform high magnetic flux density recording and reproduction.

Usually, a new type of magnetic head consists of a main core made of a high saturation magnetic flux density material with a thickness matching the track width, sandwiched between a reinforcing core made of a non-magnetic material such as glass, and both cores glued together. Manufactured by integrating.

The reinforcing core reinforces the main core, which has relatively low mechanical strength, but since it is non-magnetic, there is a problem in that the magnetic resistance of the magnetic head increases.

Therefore, a magnetic head as shown in FIG. 9 has been proposed.

The magnetic head has a reinforcing core (2) consisting of a non-magnetic part (3) and a magnetic part (end) on both sides of the main core (upper), which has a gap part G and a coil window (5). It is formed by joining and fixing. A tape contact surface (6) is formed in the non-magnetic part (3), and a coil window (4) is formed in the magnetic part (2). The non-magnetic portion (3) is made of glass, and the magnetic portion (to) is made of Mn-Zn ferrite.

In the magnetic head described above, most of the reinforcing core (2) is made of a magnetic material, so that magnetic resistance is reduced and relatively good recording and reproducing efficiency can be obtained.

(Problem to be Solved by the Invention) However, in the above magnetic head, the non-magnetic portion (3) of the reinforcing core (2) is a circle having a chord length equal to the width in the longitudinal direction of the contact surface of the head. Since it is formed in an arc shape, the thickness (chord height) b of the non-magnetic material portion (3) in the head height direction becomes large, and the gap portion G and the magnetic material portion (to) are separated from each other by a large distance. As a result, the magnetoresistance of the magnetic head is still large (therefore, there is a limit to the improvement of recording and reproducing efficiency).

(Means for solving the problem) In order to solve the above problem, as shown in Fig. 1, the thickness of the non-magnetic material part (3) in the head height direction (chord height) It is clear that it is sufficient to manufacture a magnetic head smaller than the string height (b). However, until now, there has been no known method for manufacturing the magnetic head shown in FIG. 1 efficiently and at low cost.

The present invention relates to an improvement in the manufacturing method of the magnetic head shown in FIG. 1, and in particular to the manufacturing process of the reinforcing core (2).

In the manufacturing process of the reinforcing core (2), after forming a pair of block halves (2IIIl circles) using magnetic material, a coil window (4) is formed in at least one of the block halves.
A coil groove (421) is provided in a recessed manner to form a coil groove (421). Also, a coil groove (421) is provided in the first joint surface (to) of both block halves 1. A pair of non-magnetic grooves f41 (4 first grooves extending along the four sides are each recessed approximately perpendicularly to the joining surface 241 (to)).Next, when joining both block halves (21 (2υ) to each other Then, the non-magnetic groove +41 (4) is first filled with a non-magnetic material and fused to form an integral block.Finally, the block is machined to form a coil window (4) and a non-magnetic material. A reinforcing core (2) comprising a body (3) is produced.

Next, a reinforcing core (2) is bonded and fixed to the side surface of the main core (1) to manufacture a head chip body (9).

In the finishing process, the head chip body (9) is machined to complete the magnetic head having the facing surface 1fi (61). ) is processed until a non-magnetic material portion (3) appears at the center and a predetermined gap length is obtained.

(Function) Non-magnetic groove +4 (l f4υ is the block half (2II
When recessing the coil groove (turn) in I (2υ), it can be easily formed using, for example, a diamond grindstone.Also, the non-magnetic groove +41 +4 first is filled with a non-magnetic substance and fused. In this method, both block halves (2I) are formed using a method similar to the well-known method of bonding and fixing the first and second blocks using, for example, molten glass. A method can be adopted in which it is inserted into the groove for joining the halves and heated and melted.Wave groove +41 (41
), it is possible to form a narrow groove width, so the molten glass fills the wave grooves with no gaps due to surface tension.
It will be fused.

When joining the reinforcing core (2) to the main core (1), the lower end (depth end) A of the gap G of the main core (1) is connected to the non-magnetic groove (40) of the reinforcing core (2) ( 4. The joining position is determined so that they are as close to or overlap each other as possible (see FIG. 6).

In the finishing process, the head chip body (9) is machined until a predetermined gap length is obtained, so that the side surface of the non-magnetic part (3) on the gap side is machined, and the machined surface is Forms part of the contact surface (6).

(Effects) The process of forming the block half (2) which will become the reinforcing core (2) first is the non-magnetic part (3), as described above, and can be efficiently incorporated into the conventional magnetic head manufacturing process. Therefore, productivity is high.

According to the manufacturing method of the present invention, the thickness a of the non-magnetic material portion (3) in the head height direction can be made as small as possible. The magnetic head approaches or overlaps the magnetic body portion of the magnetic head, thereby sufficiently reducing the magnetic resistance of the magnetic head.

(Example) Fig. 1 shows a Sendust magnetic head obtained by the manufacturing method of the present invention, in which coil windows (4) are provided on both sides of a main core (1) comprising a gap G and a coil window (5). A pair of reinforcing cores +21 (integrated with 21).

The main core (1) is made by joining a pair of Sendust core halves (1ωαω) as shown in FIG. 4, and is manufactured by a conventionally known method.

2 to 5 show the manufacturing process of the reinforcing core (2).

As shown in Fig. 2 (a pair of block halves made of Mn-Zn ferrite) (2υ), grooves are processed using a diamond grindstone (not shown).
The joining grooves (43) and the coil grooves (41) are recessed close to each other at a predetermined pitch p, and both block halves (towards)
Qυ has a slit-shaped non-magnetic groove (40) (41
) are formed perpendicularly to the joint surface I241 (to).

In addition, in the first block half (2), there is a space between the joining groove (43) and the non-magnetic groove f41, and a space between the non-magnetic groove (41 and the coil groove f41).
The joint surfaces between grooves 3 and 3 are polished to form communication surfaces that allow adjacent grooves to communicate with each other.

As shown in the figure (a glass rod (2) is inserted into the joining groove (43), and heat treatment is performed with the two block halves (21) joined together to melt the glass rod round.

As a result, as shown in FIG.
From there, it flows into the non-magnetic groove +4G+4υ and the coil groove (4υ). At this time, the narrow non-magnetic groove (41 (4υ) is filled with molten glass due to surface tension. The molten glass cools and solidifies. Both block halves 12I (company)
becomes a single block.

After polishing the side surface of the above block to the position of the broken line E, cutting it along the broken line, and slicing it to a predetermined thickness t to form a large number of reinforcing cores (2) as shown in Fig. 4. I can control it.

By arranging the reinforcing cores (2) on both sides of the main core (1) and fixing them with a resin adhesive,
A head chip body (9) shown in FIG. 5 is formed.

At this time, the positional relationship of the reinforcing core (2) with respect to the main core (1) is as shown in FIG.
I +41) on the coil window (4) side and the main core (
The distance j between the gap part G and the depth end A in 1) is 10
It is defined to be a predetermined value of 0 μm or less.

The upper surface of the head chip body (9) shown in FIG. 5 is polished to the position indicated by broken line F where a predetermined gap length is obtained, thereby completing the magnetic head shown in FIG. 1. At this time, the non-magnetic portion (3) of the reinforcing core (2) is exposed on the polished surface and forms part of the tape contact surface (6).

Further, as shown in FIG. 7, the tape contacting surface (6) forms a convex curved surface (61) in the vicinity of the gap portion G, and also forms concave curved surfaces (616D) continuously on both sides between the convex curved surfaces. As a result, a smooth wavy curved surface with two inflection points is created.

As shown in FIG. 7, when the magnetic tape (8) is tracked by the magnetic head, the magnetic tape is attached to the boundary B%B between both core halves wtn of the reinforcing core (2) and the non-magnetic portion (3). If (8) comes into contact, there is a possibility that the contact portion becomes a pseudo gap portion and adversely affects the recording and reproducing performance. However, since the tape contacting surface (6) of the magnetic head has a convex curved surface with a relatively large curvature where the gap portion G exists, there is no such risk.

In the magnetic head manufactured by the above method, as shown in FIG. 6, the distance l between the depth end A of the gap portion G and the magnetic material portion of the reinforcing core is formed to be 100 μm or less.
Magnetic resistance is extremely low, so recording and reproducing performance is good.

In order to confirm the performance of the magnetic head shown in Fig. 1, Figure 8 shows the performance compared to the conventional magnetic head, with the horizontal axis representing the recording frequency f (MHz) and the vertical axis representing the maximum reproduction output V (mV). This is a comparison. The curve (7) represents the conventional magnetic head whose reinforcing core is entirely made of non-magnetic material, the curve (to) represents the conventional magnetic head shown in Figure 9, and the curve (7) represents the magnetic head of the present invention shown in Figure 1. This is a performance curve obtained for a magnetic head.

As is clear from the figure, the magnetic head according to the present invention has better performance over the entire recording frequency range than the conventional magnetic head.

[Brief explanation of the drawing]

FIG. 1 is a perspective view of a magnetic head obtained by implementing the present invention, FIG. 2 is a side view of a half block serving as a reinforcing core,
FIG. 3 is a side view of the block halves joined and fixed;
FIG. 4 is a perspective view of the magnetic head before bonding, FIG. 5 is a perspective view of the magnetic head before tape contact surface is formed, FIG. 6 is an explanatory diagram of the positional relationship of the non-magnetic groove with respect to the gap, 8 is a graph showing the performance of the magnetic head, and FIG. 9 is a partially cutaway oblique view of a conventional magnetic head.

Claims (1)

[Claims] [1] A process of manufacturing a main core (1) having a gap portion G and a coil window (5), and a pair of block halves (20)
A coil groove (42) serving as a coil window (4) is recessed in at least one of the block halves (20) (21).
) are joined and fixed together to form an integral block,
A step of manufacturing a reinforcing core (2) provided with a coil window (4) by machining the block, and inserting the reinforcing core (2) on one side or both sides of the main core (1) with each other's coils. window(
5) Match (4) and join and fix the head chip body (
9); and a finishing step of machining the head chip body to form a contact surface (6) to be in sliding contact with the recording medium.
In the reinforcing core manufacturing process, both block halves (20) (2
1) are formed of a magnetic material, and their bonding surfaces (24
) (25) has a pair of non-magnetic grooves (40) and (41) extending along the coil groove (42) at opposing positions on the contact surface side of the coil groove (42), respectively, on the bonding surface (24). )(25
), and both block halves (20) (
21) or after joining, the non-magnetic groove (4
0) A magnetic head characterized in that (41) is filled with a non-magnetic material and fused, and processed in the finishing step until the non-magnetic material is exposed at the center of the contact surface (6). Production method. [2] In the finishing process, the contact surface (6) forms a convex curved surface (60) near the gap portion, and concave curved surfaces (61) (61) are formed continuously on both sides of the convex curved surface. 2. The manufacturing method according to claim 1, whereby a smooth wavy curved surface having two inflection points can be obtained by doing so.