JPS62177715A - Magnetic head - Google Patents

Abstract

PURPOSE:To prevent magnetic saturation of a core facing a recording and reproducing magnetic circuit by forming this core out of cores of an erasing magnetic circuit with materials which have a saturation magnetic flux density higher than that of the other cores. CONSTITUTION:An erasing magnetic circuit 16 consists of an I-shaped core block 17 and a plane plate-shaped core block 18 consisting of materials having a high saturation magnetic flux density (like a 'Sendust(R)'). These blocks 17 and 18 are provided with grooves 17a and 18a constituting a track width, and erasing gaps 10 between faces facing each other of blocks are joined by a glass 19. Similarly, a recording and reproducing magnetic circuit 20 consists of core blocks 21 and 22 which are allowed to face each other through a gap 3 and are joined and is aligned and is joined to the circuit 16. By this constitution, magnetic saturation of the core 18 is prevented and the interval between magnetic gaps of circuits 16 and 20 is narrowed.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a magnetic head, and more particularly to a magnetic head in which a magnetic circuit for magnetic recording and reproduction and a magnetic circuit for erasing are arranged in close proximity to each other. It is something.

[Prior Art] A conventional magnetic head of this type records only in the center of a track of a flexible magnetic disk, and erases data on one side edge. Taking as an example a magnetic head that performs recording and reproduction using a so-called tunnel erase method, examples thereof are shown in FIGS. 3 to 5.

The example shown in FIGS. 3 and 4 is called a bulk type, and includes a first magnetic circuit having a magnetic gap 3 for recording and reproducing, and a 6T4 side surface of the magnetic gear amplifier for recording and reproducing. It has a second magnetic circuit with an erase gap 10.10'.

The first magnetic circuit consists of a first core 1 into which a pobbin 5 wound with a recording/reproducing coil 4 is inserted, and a second core 2 which is butted against the core 1 through a recording + tr Ikukawa cap 3. and a third core 6 that bridges between the core 1 and the rear end of the core 2, and the cores 1 and 2.6 are made of ferrite, which is a high magnetic permeability material.

Similarly, the second magnetic circuit includes a core 8 in which a pobbin 12 with an erasing coil 11 wound therein is inserted, and a second magnetic circuit that is butted against this core 8 through an erasing gap 10 and 10'. It is composed of a core 9 and a third core 13 that is bridged between the rear ends of the cores 8 and 9.

The first magnetic circuit and the second magnetic circuit each have a second magnetic circuit.
The core 2.9 and the third core 6.13 are butted together with a spacing plate 7.14 made of non-magnetic ceramic, glass, etc. in between, and a recording/reproducing gap 3 and an erasing gap 10.10 are formed. ' is the spacer plate 7 and the second core 2.9
It is configured to have a gap interval G between the two.

In such a tunnel erase type magnetic head, it is preferable to set the gap interval G between the recording/reproducing gap and the erasing gap as far apart as possible in the design of the magnetic circuit.

However, in recent years, with the miniaturization of magnetic recording media, the disk diameter has become smaller and the density has become smaller.

As the disk diameter becomes smaller, it is required to reduce the gap distance, and in order to perform higher density recording and reproduction, it becomes necessary to reduce the gap distance.

However, in order to reduce the gap interval G, it is necessary to reduce the widths Gl and G2 of the second core 2.9 shown in FIG. 4, and the cross-sectional area of the second cores 2 and 9 becomes smaller. The magnetic saturation of the core is likely to occur, resulting in '1', and in particular, sufficient erasing cannot be performed.

As a solution to this problem, the second core 2°9 is made common to prevent magnetic saturation, as shown in Fig. 5, and the common parts with Figs. 3 and 4 are shown in Fig. 5. are given the same reference numerals and their explanations will be omitted.

That is, the first core 1.8 is recorded in the second core 15, which is shared by the first magnetic circuit, the second magnetic circuit, and the second magnetic circuit. They are arranged opposite to each other with an erase gap 10, 10' interposed therebetween.

[Problems to be Solved by the Invention] When the above-described structure is adopted, the cross-sectional area increases because the second core 15 is shared, but the track width of the recording/reproducing gap 3 is formed in the second core 15. Grooves 15a, 15a
' and the groove 15b forming the width of the erase gap 10.10'.

15c, 15c must be provided, and it is difficult to achieve positional accuracy between the tracks, resulting in a decrease in the yield of parts processing.

In addition, when providing the recording/reproducing gap 3 and the erasing gap 10.10' on both sides of the second core 15, it is difficult to provide them on the same surface, and in order to form them separately, two types of welded glass with different softening points are required. The drawback was that the manufacturing method for the core became difficult.

[Means for solving the problems] In the present invention, in order to solve the above-mentioned problems,
In a magnetic head in which tjSl for recording and reproducing and a second magnetic circuit for erasing are arranged close to each other, in the second magnetic circuit for erasing, the second core facing the first magnetic circuit is connected to another core. A structure made of a material with higher saturation magnetic flux density was adopted.

[Function] Adopting a double structure prevents magnetic saturation of the second core of the second magnetic circuit for erasing, and reduces the distance between the magnetic gaps of the first magnetic circuit and the second magnetic circuit. can be made narrower and easier to manufacture.

[Example] Hereinafter, the present invention will be described in detail based on the example shown in the drawings.

FIG. 1 and FIG. 2 illustrate one embodiment of the present invention, and the same parts as in FIGS. 3 to 5 are denoted by the same reference numerals, and the explanation thereof will be omitted.

FIG. 2 is a perspective view showing a method of manufacturing a magnetic head, with the coil bobbin and third core removed.

First, as shown in FIG. 2A, in this embodiment, the second magnetic circuit 16 for erasing consists of a substantially single-shaped core block 17 serving as the first core and a core block 17 having a large saturation magnetic flux density serving as the second core. Materials, such as Fe, An, and Si called sendust
It is composed of a 41 plate-shaped core block 18 made of an alloy.

Next, as shown in FIG. 3B, grooves 17a forming the track width are formed in the core blocks 17 and 18.

18a, and a butting surface 17b of each core block,
18b is polished and an erase gap 1 is created on the abutting surface 17b.
A thin layer of non-magnetic material forming 0 is provided. Subsequently, as shown in FIG. 2C, the grooves 17a and 18a provided in the core blocks 17 and 18 are aligned and butted against each other, and glass 19 is used to fill and join the core blocks and the grooves. 2 magnetic circuit core block 16 is completed.

Similarly, as shown in FIG. 2D, a single-shaped core block 21 serving as a first core and a flat core block 22 serving as a second core constituting a first magnetic circuit for recording and reproducing are recorded. abutting each other through the reproduction gap 3, and the groove 21a,
22a is filled with glass 19 and bonded to obtain a first magnetic circuit core block 20. Next, the grooves 21a, 22a of the first magnetic core block 2° and the grooves 17a, 18a of the second magnetic circuit core block 16 are aligned, and as shown in FIG.
), as shown in (E), the plate-shaped core blocks 18.22 (which will become the second core) are joined together, and the cutting lines 24.22 are joined together.
At step 25, a magnetic head 26 shown in FIG. 2(F) is obtained.

nt after this? As with the conventional magnetic head described above, a coil bobbin and a third core are attached to complete the magnetic head 26.

According to the configuration 1- below, the second
Core saturation due to a decrease in the cross-sectional area of the cores 18 and 22 can be prevented by using a material for the second core 18 of the second magnetic circuit 16 that has a higher saturation magnetic flux density than the other cores.

The reason why only the second core 18 of the second magnetic circuit 16 is made of a material with a high saturation magnetic flux density is that in the case of a tunnel erase type magnetic head, when erasing is performed in the erase gap of the second magnetic circuit, a DC current is used. However, if a material such as sendust with a high saturation magnetic flux density is used on the recording/reproducing gap side of the first magnetic circuit, eddy current loss will increase due to high frequency recording and reproduction. This is because lamination of thin plates or thin films becomes necessary, which complicates the manufacturing method of the core.

[Effects] As is clear from the above description, according to the magnetic head of the present invention, the second core of the second magnetic circuit is made of a material having a higher saturation magnetic flux density than other cores, thereby reducing the gap distance. In a small-sized, high-density flexible magnetic head, saturation of the second core can be prevented, and the core can be easily processed, making it possible to provide a magnetic head with high yield.

[Brief explanation of drawings]

2. Fig. 1 is a plan view showing an embodiment of the present invention, Fig. 2 (A)
-(F) are perspective views showing the manufacturing method of a magnetic head in an embodiment of the present invention, FIG. 3 is a perspective view showing a conventional magnetic head structure, and FIG. 4 is a 1-plane view of a conventional magnetic head. , 5th
The figure is an L side view of another embodiment of the conventional magnetic head. l, 21...first core of first magnetic circuit 2.15.
22...Second core 6...Third core 8.17...First core 9.18 of the second magnetic circuit
...Second core 13...Third core 5.12...Bobbin 4.11...Coil 7.1
4... Spacing board

Claims (1)

[Claims] a first core around which a coil is wound; a second core joined to the first core through a magnetic gap;
a first magnetic circuit for magnetic recording and reproducing, which is composed of a third core that magnetically connects the second core; and a second magnetic circuit for erasing, which is configured in the same manner as the first magnetic circuit. is characterized in that the second cores of the second magnetic circuit are made of a material having a higher saturation magnetic flux density than the other cores in the magnetic head in which the respective second cores are arranged close to each other so as to face each other. magnetic head.