JPH0722229B2 - Method of manufacturing magnetic shield plate - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial application] The present invention is applied to an inductive magnetic head having a plurality of magnetic cores such as a stereo magnetic head and an auto-reverse magnetic head, and is adjacent to the magnetic head. The present invention relates to a method of manufacturing a magnetic blocking plate that magnetically blocks between magnetic cores to prevent crosstalk.

[Prior Art] Conventionally, as the above-mentioned magnetic shield plate, for example, one integrally formed with a spacer plate that appropriately keeps a space between adjacent channels (between magnetic cores) of a magnetic head is often used. Such a magnetic blocking plate is shown in FIGS. 2 (a) and 2 (b).
Although various shapes are used as shown in, the basic structure is magnetic plate such as permalloy.
A structure in which non-magnetic plates 1 and 3 made of Ni-Cu alloy or the like are bonded to both sides of 2 and 4 by resin bonding or welding is adopted. Recently, there has been proposed a manufacturing method in which a non-magnetic plate is clad on both sides of a magnetic plate by pressure bonding in a heated state and cut into a shape as shown in FIGS. It is widely used due to its simple manufacturing process.

[Problems to be Solved by the Invention] However, recently, in the field of magnetic heads, for example,
In order to reduce the inner volume of the case of the magnetic head in order to reduce the size and weight, the non-magnetic plates 5 to 5 are formed only on a part of both side surfaces of the magnetic plate 1 as shown in FIGS. 3 (a) and 3 (b). Magnetic shields having a structure in which ′ are joined have come to be used. Even with such a structure, the space between adjacent channels can be maintained as in the conventional case, the magnetic blocking effect is not changed, and the occupied space can be reduced, so that the use is increasing.

However, such a structure cannot be manufactured by a simple process such as pressing the clad plate as it is as described above, and there is a problem that the number of manufacturing steps increases and the manufacturing cost increases.

[Means for Solving the Problems] In order to solve the above-mentioned problems, according to the present invention, a magnetic blocking plate in which a non-magnetic plate is joined to only opposite portions of both side surfaces of a magnetic plate having a predetermined shape. And a step of joining strip-shaped non-magnetic plates having a width narrower than the magnetic plate to both side surfaces of the strip-shaped magnetic plate by pressure bonding in a heated state to obtain a strip-shaped composite plate, A step of obtaining a magnetic shield plate by pressing at a predetermined interval in the longitudinal direction of the strip-shaped composite plate so that the predetermined shape is obtained from the composite plate over the joined portion and the non-joined portion of the non-magnetic plate; And a step of magnetically annealing the magnetic shield plate.

[Operation] According to such a configuration, it is possible to easily obtain a strip-shaped composite plate by pressure bonding in a heated state in the step of obtaining the composite plate. Further, by obtaining a strip-shaped composite plate, it is possible to take a large number of magnetic shield plates in the cutting step by the next press.
Then, by the extremely simple steps of obtaining the composite plate, cutting process, and magnetic annealing process, the magnetic shield plate in which the non-magnetic plate is bonded only to the opposite portions of both side surfaces of the magnetic plate having a predetermined shape can be easily formed once. A large number can be manufactured.

[Embodiment] An embodiment of a method for manufacturing a magnetic shield according to the present invention will be described in detail below.

1 (a) and 1 (b) illustrate a manufacturing process according to an embodiment of the present invention.

In this embodiment, first, as shown in FIG. 1 (a), strip-shaped non-magnetic plates 7 and 7 having narrower widths are formed on both side surfaces of the strip-shaped magnetic plate 7.
And roll them with high temperature while rolling rollers 8 and 8 with arrow F
As shown in (1), the composite plate 9 is obtained by rolling under pressure and bonding the non-magnetic plates 7, 7 to only one side edge of each side of the magnetic plate 6 by pressure bonding. In this case, for example, a permalloy plate or the like is used as the magnetic plate 6, and a Ni—Cu alloy plate or the like is used as the non-magnetic plate 7. When both are used, the above heating temperature is about 1150 ° C.

Next, as shown in the ring portion in FIG. 1 (b), the composite plate 9 is cut into a substantially U-shape by press punching or the like over a portion where the non-magnetic plate 7 is joined and a portion where it is not joined. A magnetic blocking plate 10 similar to that shown in FIG.

Next, in order to improve the magnetic characteristics of the magnetic plate 6 portion of the magnetic shield plate 10, the magnetic shield plate 10 is magnetically annealed to complete the magnetic shield plate 10. For example, when the above-mentioned permalloy plate is used, the magnetic annealing is performed by heating in hydrogen gas at a temperature of about 1000 ° C. for about 2 hours and then cooling.

According to the manufacturing process of this embodiment, as compared with the conventional method of cutting from the clad plate, which cannot manufacture the magnetic shield plate having the structure as shown in FIGS. 3 (a) and 3 (b), 3 (a) and 3 (b) in substantially the same extremely simple process, except that the non-magnetic plates 7 and 7 are joined to only a part of both side surfaces of the magnetic plate 6 in the process of FIG. Magnetic shield plate can be manufactured at low cost.

[Effect] As is apparent from the above description, according to the method of manufacturing a magnetic shield of the present invention, a strip-shaped non-magnetic plate having a width narrower than that of the magnetic plate is heated on both side surfaces of the strip-shaped magnetic plate. A step of joining by strip bonding to obtain a strip-shaped composite plate, and in the longitudinal direction of the strip-shaped composite plate so that a predetermined shape can be obtained from the strip-shaped composite plate over the joined portion and the non-joined portion of the non-magnetic plate. By a very simple process of cutting with a press at a predetermined interval to obtain a magnetic shield plate, and a step of magnetically annealing the magnetic shield plate, only a part of both sides of the magnetic plate having a predetermined shape facing each other is removed. It is possible to easily manufacture a large number of magnetic shield plates to which magnetic plates are joined at one time, and to manufacture them at low cost.

[Brief description of drawings]

1 (a) and 1 (b) are explanatory views of the manufacturing process of the magnetic shield according to the first embodiment of the present invention, and FIGS. 2 (a) and 2 (b), respectively.
FIG. 3B is a perspective view of a magnetic shield plate for explaining a conventional manufacturing method, and FIGS. 3A and 3B are perspective views of shield plates having different structures. 6 ... Magnetic plate, 7, 7 '... Non-magnetic plate 8 ... Rolling roller, 9, 9' ... Composite plate 10 ... Magnetic blocking plate

Claims (1)

[Claims] 1. A method of manufacturing a magnetic blocking plate in which a non-magnetic plate is joined only to opposite portions of both side faces of a magnetic plate having a predetermined shape, wherein the magnetic plate is formed on both side faces of a strip-shaped magnetic plate. A step of joining a narrow band-shaped non-magnetic plate by pressure bonding in a heated state to obtain a band-shaped composite plate, and the predetermined shape from the band-shaped composite plate to the non-bonded part and the non-bonded part of the non-magnetic plate. As obtained, the method comprises: a step of obtaining a magnetic shield by cutting with a press at predetermined intervals in the longitudinal direction of the strip-shaped composite plate; and a step of magnetically annealing the magnetic shield. Method of manufacturing a blocking plate.