JPH0997405A - Magnetic head and its production - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the manufacturing cost by decreasing the number of parts and shortening the time for working and assembling and to enhance the dimensional accuracy. SOLUTION: Laminated magnetic cores 2a, 3a, 3b, 3b are fixed to frames 4a, 4b formed by subjecting hoop materials to pressing work. These laminated magnetic cores 2a, 3a, 3b, 3b fixed to these frames 4a, 4b are subjected to an annealing treatment. The laminated magnetic cores are solidified with a resin and the front ends of the frame laminated magnetic core, i.e., surfaces 16 to be butted are subjected to surface polishing for the purpose of forming a gap. The magnetic cores formed by polishing in such a manner, a coil bobbin 5 wound with the coil and terminals are temporally assembled. The frames are welded in order to fix the laminated magnetic cores in the state of butting the cores against each other. The laminated magnetic cores 2a, 3a, 3b, 3b are then sealed with a resin to produce the magnetic head.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic head and its manufacturing method. More specifically, the present invention relates to a magnetic head having a structure in which half halves of divided magnetic cores are held in a frame, butted together, and a coil bobbin is fitted between them, and then assembled in a shield case, and a manufacturing method thereof. .

[0002]

2. Description of the Related Art In a conventional magnetic head of this type, as shown in FIG. 8, for example, a coil bobbin 102 is provided between core halves 101 which constitute one magnetic core in a butted state.
Are assembled so as to fit into the shield case 104 and then sealed with the resin 106. The magnetic core halves 101 are abutted against each other while being held by a pair of left and right frames 103 that are similarly divided, and are housed in a shield case 104. The frame 103 is a block of a non-magnetic material that holds the magnetic core halves 101 adjacent to each other at a constant interval so that the magnetic core halves 101 are not in contact with each other, and is usually formed by die casting. The frame 103 holds the magnetic core 101 using, for example, a groove. Reference numeral 105 in the figure is a magnetic shield plate.

The magnetic head having such a structure has been conventionally manufactured in accordance with the procedure shown in the process diagram of FIG. That is, several magnetic core halves 101, ..., 101, which have been punched out into a fixed shape by press working, are aligned, assembled into the frame 103 together with the shield plate 104, and temporarily fixed with a resin adhesive. And one block half (this is called a mount set in this specification) 10
After that, it is assembled in the shield case 104, and positioning and temporary assembly are performed by screws 108 or springs. The coil bobbin 102 is inserted and held between the magnetic core halves 101, 101 when the pair of left and right mount sets 107, 107 are butted. Then, the resin 106 is injected into the shield case 104 and sealed, and the magnetic core halves 101, 101 and the coil bobbin 1 are sealed.
02, the frame 103, etc. are fixed. Here, the magnetic core half body 101 and the shield case 104 are separately subjected to annealing treatment for improving the magnetic characteristics before being assembled.

[0004]

However, in the structure of this conventional magnetic head, the frame 1 manufactured by die casting or the like after aligning several magnetic core halves 101.
Since the mount set 107 is formed by inserting the mount set 107 into the groove 03, and the mount set 107 is inserted into the shield case 104, it takes time to assemble. In addition, since the number of parts is large and the dimensional accuracy is low, there is a problem in that the actual working time (real time) is increased in order to process and assemble them. Also, the magnetic core half 101 and the frame 1
Since a so-called core mount method in which the mount set 107 is housed in the shield case 104 and hardened with resin after the mount set 107 is configured by temporarily bonding 03 with resin, the magnetic core half body in the temporarily fixed state is adopted. There arises a problem that the positions of 101 and 101 are displaced before resin sealing and the characteristics of the magnetic head are deteriorated.

Further, a mount group 10 divided into two parts on the left and right sides.
Since the screws 7 (or springs or the like) 108 are used to join 7 and 107, the two mount sets 107, 107 are different due to the difference in contraction when the epoxy resin 106 for sealing is cured.
It is necessary to manage the gaps between the gaps 107 in the gap depth direction and the gap length direction.

In the conventional magnetic head manufacturing method, since the magnetic core half body 101, the shield case 104, and the shield plate 105 are separately annealed, heat treatment time and cost are added for each process. The Rukoto. Moreover, since they are separately annealed, there is a problem that it is difficult to prevent the stress at the time of assembly and the deterioration of the magnetic characteristics due to adhesion.

An object of the present invention is to provide a magnetic head having a structure capable of reducing the number of parts, shortening the working / assembling time and reducing the manufacturing cost, and a method for manufacturing the same. Another object of the present invention is to provide a magnetic head with high dimensional accuracy and a method for manufacturing the same.

[0008]

In order to achieve such an object, the present invention is a magnetic head having a pair of magnetic cores holding a frame butted against each other to form a magnetic gap, which is composed of a plate material having a bent upright portion. A frame and a magnetic core fixed to the bent upright portion are provided.

In the method of manufacturing a magnetic head of the present invention, a step of forming a frame from a hoop material by pressing and fixing the laminated magnetic core to the frame, and a step of annealing the laminated magnetic core fixed to the frame. When,
A step of solidifying the laminated magnetic core with a resin, a step of planarly polishing the surfaces of the frame and the laminated magnetic core that are abutted against each other to form a gap, and a step of temporarily assembling the polished one with a bobbin wound with a coil and a terminal. , A step of welding a frame to fix the laminated magnetic cores in a state of abutting each other, and a step of sealing the laminated magnetic cores with a resin.

Further, in the method of manufacturing a magnetic head of the present invention, after the laminated magnetic core is fixed to the frame, a shield plate is further inserted between the laminated magnetic cores, and the joint portion thereof is brazed and joined to the shield plate. The laminated magnetic core and the frame thus annealed are simultaneously annealed.

Therefore, a desired number of magnetic core halves or clad structure magnetic core halves are bent in a U-shape while being fixed to the bending upright portions of the frame punched into a predetermined shape by pressing. Housed in. Then, the frame is abutted against the other frame forming a pair and integrated by being welded to form a shield case, and the opposite magnetic cores housed therein are abutted to form a predetermined magnetic gap. Since the magnetic core and the frame are fixed to each other in advance so that the positional relationship is constant, the positions in the gap depth direction and the gap length direction between the magnetic cores are also fixed by the butt welding of the frames.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION The structure of the present invention will be described below in detail based on an example of an embodiment shown in the drawings.

FIG. 1 shows an embodiment of the magnetic head of the present invention. This magnetic head is composed of two mount sets 1 forming a pair.
A and 1b are joined by butt laser welding or the like so that the coil bobbin 5 is inserted between them.
The mount sets 1a and 1b are fixed by caulking to frames 4a and 4b formed by bending a plate material in a U-shape, and sides of the frames 4a and 4b, which are measured sides of the frames 4a and 4b. Magnetic core half 2
a, 2b, 3a, 3b. The magnetic core halves 2a, 3a are paired with the other magnetic core halves 2b, 3
It is formed in a substantially U shape so as to form a closed magnetic path when it is abutted with b, and coil bobbins 5 and 5 are attached to the sides 8 away from the magnetic tape sliding contact surface 9, respectively. . The magnetic core halves 2a, 2b, 3a, 3b are made of a thin plate of a magnetic material to prevent eddy current loss, and more preferably a clad material of a magnetic material and a magnetic insulating material (non-magnetic material). Of course, in some cases, the magnetic core halves 2a, 2b, 3a, 3b which are independent of each other may be separated by a few layers.
It may be formed by stacking one sheet.

Adjacent magnetic core halves 2a, 3a and 2
Shield plates 6 and 6 are respectively arranged between b and 3b. One end of the shield plate 6 has a magnetic tape sliding contact surface 9
Of the magnetic core halves 2a, 3a and 2 which are adjacent to each other,
A magnetic shield is provided between b and 3b and between coil bobbins 5 and 5. Although not shown, the shield plate 6 is, for example, a clad material of a magnetic material and a non-magnetic material that covers the entire surface, or a plate of a magnetic material and a non-magnetic material that partially covers (a portion that requires magnetic insulation). It is composed of a magnetic material plate and a clad material. As the magnetic material, for example,
The use of permalloy material such as PC80 is preferred. The non-magnetic plate near the magnetic tape sliding contact surface 9 is provided with a predetermined space between the adjacent magnetic core halves 2a, 3a and 2b, 3b to prevent a magnetic short circuit and to be provided between the magnetic cores. It functions as a spacer that defines the positional interval. Here, the shield plate 6 is not particularly required when two or more magnetic cores are not provided as in the present embodiment, that is, when one magnetic core is provided. The shield plates 6 and 6 are pre-assembled into the two mount sets 1a and 1b.

The frames 4a and 4b are composed of the magnetic core half body 2.
a, 3a or 2b, 3b and half of the shield plate 6 are held, and as shown in FIG. 4, a plate material is punched and bent into a U-shape. The frames 4a, 4b are made of a magnetic material, and like the magnetic core halves 2a, 2b and 3a, 3b, are configured to form one case when they are butted. Here, the lower portions 10a, 10b of the frames 4a, 4b
Is bent so as to be located inside the coil bobbins 5 and 5, and is provided so as to partition the coil bobbins 5 and 5. The abutting surface portions of the frame lower portions 10a and 10b are joined by laser welding or the like.
As the plate material, for example, a hoop material (coil material) is used.

Although the coil bobbin 5 is not particularly limited, it is composed of a barrel-shaped body around which the coil is wound and flange portions projecting from both ends thereof, and the coil is attached to the bobbin terminal embedded in the flange portion. It is connected.

Next, the assembly of this magnetic head will be described with reference to FIG. First, the hoop (coil material) material 11 is punched by a press to form a developed frame 4a or 4b as shown in FIG. The magnetic core halves 2a, 3a (or 2
The pin 12 for caulking for fixing (b, 3b) is integrally formed. Therefore, the magnetic core halves 2a, 3a,
The frame 4a or 4 in the expanded state so that the pin 12 penetrates through holes (not shown) formed in 2b and 3b.
magnetic core halves 2a, 3a (or 2b, 3
b) is piled up, the position is adjusted, and then the pin 12 is crushed and crimped. The punching of the frames 4a, 4b and the setting and crimping of the magnetic core halves 2a, 3a, 2b, 3b are performed by a so-called press mount assembly which is simultaneously performed in one pressing step. Next, the frames 4a and 4b in the expanded state
Is cut from the hoop material 11 along the cutting line 13. Then, the frame 4a in the unfolded state along the folding line 14,
The folding upright portions 17, 17 on both sides of 4b are folded to complete a U-shaped frame. Then, a long shield plate 6 before being cut to a predetermined size is inserted between the magnetic core halves 2a, 3a, 2b, 3b held on both sides of the frames 4a, 4b by crimping. For example, as shown in FIGS. 6A and 6B, the magnetic core halves 2a, 3a or 2 fixed to the frame 4a or 4b.
A long shield plate 6 is inserted between b and 3b and a plurality of mount sets 1a and 1b are fitted. At this time, the magnetic core halves 2a and 3a (or 2b and 3b) near the gap, the shield plate 6 and the frame lower portion 10a (or 10b) near the coil bobbin 5 and the shield plate 6 are brazed. As brazing, it is preferable to use hard brazing using brazing. For example, silver braze 15 is applied to the shield plate 6, and these are fixed by hard brazing. Then, the annealing process is performed at once with a large number of mount sets 1a and 1b brazed to one long shield plate 6. After that, the shield plate 6 is cut at a predetermined position, and a large number of mount sets 1a and 1b that overlap each other are cut.
Is separated. Also, depending on the case, the mount sets 1a, 1
Insert the shield plate 6 cut into a predetermined shape for each b,
It is also possible to anneal the magnetic core halves 2a and 3a (or 2b and 3b), the frames 4a and 4b, and the shield plates 6 and 6 at a time after bonding them with the silver solder 15 or another adhesive. The surface 16 of each mount set 1a, 1b that is abutted against the other mount set is flat-polished to form a gap. The two mount sets 1a and 1b thus obtained are opposed to each other, and the coil bobbins 5 and 5 are mounted between the magnetic core halves 2a, 2b, 3a and 3b, and then they are butted. At this time, the coil bobbins 5 and 5 are positioned by being fitted between the magnetic core halves 2a, 2b, 3a and 3b. And
In this state, the abutting portions near the gaps of the frames 4a and 4b and the abutting portions of the lower frame portions 10a and 10b are joined by laser welding 17 or the like, and the frames 4a and 4b form a shield case and form one block. After that, resin 7 is injected into the frames 4a and 4b to be solidified and sealed. The head thus obtained is finished by polishing the tape sliding surface 9.

The above embodiment is one preferred embodiment of the present invention, but the present invention is not limited to this embodiment, and various modifications can be made without departing from the gist of the present invention. For example, although the present embodiment has mainly described a two-channel magnetic head, the present invention is not limited to this. For example, it is possible to construct a 4-track 4-channel magnetic head by arranging and joining two frames each having a 2-channel magnetic core, or by inserting the frame into another shield case and sealing it.

[0019]

As is apparent from the above description, the magnetic head of the present invention is composed of a frame made of a plate material having a bent upright portion and a magnetic core fixed to the bent upright portion. Since a single frame serves as a frame for holding the core half body, a shield case for housing the frame, and screws or springs for positioning and fixing, the number of parts can be reduced. Further, since the magnetic core half body and the frame are fixed by the press mount assembly, the dimensional accuracy becomes extremely high and the assembly can be performed at a speed 20 to 25 times faster than the conventional one.

When a clad material is used as the magnetic core half body, it is possible to perform punching at the same time as the press frame and reduce the number of parts. In addition, when the magnetic core halves are obtained by press-punching the clad material, the labor of aligning them can be saved. Therefore, the process surrounded by the chain double-dashed line in the conventional manufacturing process shown in FIG. 7A can be omitted, and the manufacturing process can be significantly shortened.

Further, as compared with the conventional general magnetic head structure, it is possible to perform annealing at the same time while being fixed to the shield plate without annealing one by one for each component, so that the heat treatment cost is greatly increased. In addition to the reduction, it is possible to prevent the deterioration of the magnetic characteristics due to the subsequent generation of stress. Further, when a large number of mount sets are hard brazed to one long shield plate and then annealed at the same time, the cost can be further reduced.

Therefore, according to the present invention, an inexpensive magnetic head can be provided.

[Brief description of drawings]

FIG. 1 is a front view showing an embodiment of a magnetic head of the present invention.

FIG. 2 is a side view of the magnetic head of FIG.

FIG. 3 is a bottom view of the magnetic head of FIG.

FIG. 4 is a plan view showing an example of a method of manufacturing a magnetic head of the present invention, in which a frame portion of the magnetic head is punched out by a press.

FIG. 5 is a side view of the frame of FIG.

6A and 6B are diagrams showing a relationship between a frame and a shield plate before an annealing process, wherein FIG. 6A is a side view and FIG. 6B is a front view.

FIG. 7 is a diagram for explaining a difference in process between the magnetic head of the present invention and a conventional magnetic head, in which (A) is a conventional process diagram;
(B) is a process drawing of the present invention.

8A and 8B are views showing a conventional magnetic head, FIG. 8A is an exploded perspective view of a magnetic core and a frame, and FIG. 8B is a plan view showing a state where the magnetic core and the coil bobbin incorporated in the frame are incorporated in a shield case. , (C) are vertical cross-sectional views of the assembled state.

[Explanation of symbols]

 1a, 1b Mount set 2a, 2b, 3a, 3b Magnetic core half body 4a, 4b Frame 5 Coil bobbin 6 Shield plate 7 Resin 11 Hoop material 12 Caulking pin 13 Cutting line 14 Bending line 15 Silver brazing 17 Bending upright part

Claims (3)

[Claims] 1. A magnetic head comprising a pair of magnetic cores holding a frame butted against each other to form a magnetic gap, comprising a frame made of a plate material having a bent upright portion and a magnetic core fixed to the bent upright portion. A magnetic head characterized in that 2. A step of forming a frame from a hoop material by press working and fixing the laminated magnetic core to the frame, a step of annealing the laminated magnetic core fixed to the frame, and the laminated magnetic core. A step of solidifying with a resin; a step of planarly polishing the surfaces of the frame and the laminated magnetic cores to be abutted with each other for forming a gap; a step of temporarily assembling the polished one and a bobbin wound with a coil and a terminal; Welding the frame to fix the laminated magnetic cores in a butted state;
The method of manufacturing a magnetic head according to claim 1, further comprising the step of sealing the laminated magnetic core with a resin. 3. A laminated magnetic core bonded to the shield plate after the laminated magnetic core is fixed to the frame, a shield plate is further inserted between the laminated magnetic cores, and a fitting portion thereof is brazed. The method of manufacturing a magnetic head according to claim 2, wherein the frame and the frame are annealed at the same time.