JPH061531B2 - Core block structure - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a structure of a core block structure for obtaining a core chip of a magnetic head used for VTR, FDD and the like.

2. Description of the Related Art For example, a VTR magnetic head is generally a bulk type, and a specific example thereof will be described with reference to FIG. In the figure, (1) is a bulk type magnetic head, which comprises a pair of first cores (2a) and second cores (2b) made of a ferromagnetic material such as ferrite and a non-magnetic material such as glass (3). ) Is integrated and joined. (4) is a wire wound around the core chip (2). Inner and outer surfaces of the first core (2a) are formed with winding inner grooves (5) and winding locking grooves (6), and the second core (2b) is formed with a bonding glass groove on the inner surface for bonding. (7) has a winding locking groove (8) formed on the outer surface side. A magnetic gap g having a predetermined track width is formed on the top end surface of the core chip (2).

A conventional example of a method of manufacturing the core chip (2) will be described below with reference to FIGS. 5 to 10. First, as shown in FIG. 5, long rectangular rod-shaped first and second core blocks (9) and (10) that are mirror-finished are prepared. Next, as shown in FIG. 6, winding grooves (9a) (9b) are cut along the longitudinal direction of the inner and outer surfaces of the first core block (9).
Further, a groove (10a) for joining portion is cut on the inner and outer surfaces of the second core block (10) along the longitudinal direction, and a groove (10b) for winding portion is cut on the outer surface. Further, a plurality of track grooves (11) (11) ... are cut along the widthwise direction in the inner edge portions of the first and second core blocks (9) (10), leaving a predetermined track width. Form. Then, as shown in FIG. 7, the track grooves (11) (11) ... and the joint groove (10a) are filled with an adhesive material (12). The second core block (9) (10) is glass-molded, and the inner side surface which is the joint surface of the first and second core blocks (9) (10) is mirror-finished, and SiO _{2 is formed} near the upper part of the inner side surface. A non-self-control thin film (not shown) such as is deposited. Then, as shown in FIG.
-The inner surfaces of the second core blocks (9) and (10) are abutted against each other and heated and welded to be integrated to obtain a core block structure (139. And, as shown in FIG. The top end face (13a) of the block structure (13) is subjected to curved surface polishing so as to have a desired gap depth d, and further, as shown by the two-dot chain line (l) (l) ... As shown in FIG. The core chip (2) is obtained by slicing the core block structure (13) at a predetermined thickness in a direction inclined by a predetermined azimuth angle θ with respect to the alternate long and short dash lines (k) (k) ... After that, the core chip (2) is fixedly attached to the head base (not shown), the top end face is lapped, and the wire rod (4) is manually applied to the core chip (4). The first core (2a) of (2) is wound onto the second core (2b) by a predetermined number of turns, and the magnetic flux as shown in FIG. De (1)
Is manufactured.

By the way, as shown in FIGS. 8 and 9, the first core block (9) and the second core block (10) are joined and integrated to obtain a core block structure (13), and the top end surface (13a) is In the curved surface polishing process, the method shown in FIGS. 11 and 12 is usually adopted in order to obtain a predetermined gap depth d. That is, first, the upper end portion of the as shown in FIG. 11 inner surface of the winding part groove of the first core block (9) (9a) and Depusuen (D _1), first from the depth end (D ₁₎ 1
Second core block along the longitudinal direction of the core block (9)
Assuming that the line up to (10) is the depth end line (E), the depth end line (E) is magnified and visually inspected, and a reference point (D) separated from the depth end (D ₁ ) by a predetermined distance L.
₀ ) is measured in advance, and the portion indicated by diagonal lines in the figure is cut and removed. Next, as shown in FIG. 12, by performing a curved surface polishing process on the top end face (13a) based on the above-mentioned reference point (D ₀ ),
A predetermined gap depth d is obtained.

The problem to be solved by the invention is that when the first and second core blocks (9) and (10) are heated and joined together, the glass (12) packed in the track groove (11) melts. As a result, the first core block (9) may flow out to the end along the winding groove (9a). Outflow glass (12 ') is deposited over the glass end (D ₁₎ along the depth end line (E) as shown in FIG. 13. In this case, the top end face (13a) of the core block structure (13)
Since the depth end line (E) is magnified and visually inspected for curved surface polishing, its position cannot be accurately confirmed, and the reference point (D
₀ ) was sometimes difficult to measure.

Means for Solving the Problems The present invention has been proposed in view of the above problems, and technical means for solving the problems include long first and second long means.
In the core block structure in which the core blocks are integrally bonded by glass, the concave groove is formed along the lateral direction of the end portion of the bonding surface of the one core block.

Action In the present invention, since the concave groove is formed along the lateral direction of the joint surface end portion of one core block of the core block structure, the spread of the molten glass flowing out when the core blocks are joined and integrated is It is blocked by the groove.

Embodiment An embodiment of the core block structure according to the present invention will be described with reference to FIGS. 1 to 3. However, FIGS. 5 to 10
The same parts as those in the figure are designated by the same reference numerals, and duplicate description will be omitted. According to the present invention, winding grooves (9a) (9b) are formed along the longitudinal direction on the inner and outer surfaces of the long core block (9) in the same manner as the conventional method shown in FIGS. 5 and 6. Cutting process. In addition, a groove (10a) for joining portion is cut along the longitudinal direction of the inner surface of the elongated second core block (10), and a groove (10b) for winding portion is cut on the outer surface thereof. Furthermore, a plurality of track grooves (11) (1) (1) (1) are formed on the inner edge portions of the first and second core blocks (9) (10) along the widthwise direction, leaving a predetermined track width.
1) Form cutting by cutting. Then, as shown in FIG. 1, the concave grooves (21) and (21) which are the features of the present invention are formed, for example, along the lateral direction of the end portion of the joint surface of the first core block (9).
Thereafter, as in the conventional case, the low melting glass (12) (12) is filled in the track grooves (11) (11) ... And the joint groove (10a) and the first and second core blocks (9) are filled. ) The inner surfaces of (10) are butted against each other and heated and welded to be integrated to obtain a core block structure (22) as shown in FIG. Here, when the core block structure (22) is obtained, the molten glass (1
As shown in FIG. 3, 2 ') is prevented from expanding by the groove (21). Therefore, the molten glass (12) does not adhere to the depth end (D ₀ ) and most of the depth end line (E). As a result, when the depth end line (E) is enlarged and visually inspected, its position can be accurately grasped, and the measurement error at the reference point (D ₀ ) becomes extremely small.

EFFECTS OF THE INVENTION According to the present invention, it is possible to prevent the spread of the molten glass flowing out when the first and second core blocks are joined and integrated by the concave groove. Therefore, the abutting accuracy of the first and second core blocks is improved, and the top end surface of the core block structure is curved and polished with a predetermined gap depth. This greatly improves the quality of the core chip.

[Brief description of drawings]

FIG. 1 is an overall perspective view of first and second core blocks according to the present invention, FIG. 2 is an overall perspective view of a core block structure, FIG. 3 is an enlarged perspective view of an essential part of the core block structure, and FIG. 5 is an overall perspective view showing a bulk type magnetic head, and FIGS. 5 to 10 are overall perspective views showing respective steps of a conventional core chip manufacturing method.
11 and 12 are front views for explaining a conventional method for obtaining a predetermined gap depth, and FIG. 13 is an enlarged perspective view of a main part. (9) …… First core block, (10) …… Second core block, (12) …… Glass, (21) …… Groove, (22) …… Core block structure.

Claims (1)

[Claims] 1. A core block structure formed by integrally joining long first and second core blocks with glass, wherein a concave groove is formed along the lateral direction of an end portion of a joint surface of one of the core blocks. A core block structure characterized by being formed.