JPH0221411A - Magnetic head - Google Patents

Abstract

PURPOSE:To generate the grounding states of all the magnetic cores and to improve a magnetic characteristic without providing a flux gate by depositing a superconducting material extending over the prescribed range of a head front plane by plasma coating. CONSTITUTION:A device is constituted in such a way that a write head 2 and a readout head 3 are integrated in sandwich shape via a center shield plate 4, and a write magnetic gap 7 and a readout magnetic gap 11 are exposed to surfaces and are stuck closely with a magnetic tape at the time of feeding the magnetic tape. Furthermore, copper plating layers 13 and 14 with thickness of (0.2-0.3)mm are provided extending over the prescribed range of the front plane of each of the heads 2 and 3 except for the magnetic gaps 7 and 11, and also, wear-resistance layers 15 and 16 are provided by applying the plasma coating of a ceramic system superconducting material on the surfaces of the copper plating layers 13 and 14. In such a way, all the magnetic cores are set at the grounding states, and the magnetic characteristic can be improved without providing the flux gate.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a magnetic head used in a terminal device of an electronic meter, a magnetic tape device W such as a duplicator (hereinafter referred to as an MT wave device).

Conventional technology Conventionally, the core of a magnetic head used in an MT wave device, for example, a terminal device of an electronic computer, is 25 μm or more.
A laminated layer of metal magnetic material with a thickness of 50 μm is used, but in order to improve wear resistance and prevent whitening, only the magnetic gap area for writing and reading is used, and the magnetic tape contact surface around the magnetic gap is approximately There were some that had ceramic welding applied to the entire surface of the other parts, or part of the magnetic core and the part in contact with the magnetic tape, with 0.4 points remaining.

In addition, in magnetic heads for duplicators, ferrite was generally used as a magnetic material to improve wear resistance, but recently, as speeds have increased, tape speeds have increased to 64 times or 128 times faster, and cassette tape Recorder tape running speed 4.75cz/lin
When the tape speed is 64 times or 128 times higher than that of tape speed), ferrite crystal grains are likely to fall off in ferrite materials, and metal magnetic materials are sometimes used due to problems with magnetic properties and sound quality. Ceramic welding is also being considered for wear resistance.

Figure 5 is an electronic meter! ! It is a perspective view of a 172-inch, 9-track magnetic head for writing and reading, which is a terminal device of LRS, in which 31 is a reading magnetic core 32, an inter-track shield plate of the reading magnetic core 31, 33 is a deep gutter, and 34 The write magnetic core 35 is an inter-track shield plate of the write magnetic core 34, and 36 is a center shield plate interposed between the read head 37 and the write head 38.

Fig. 6 shows an example of a two-channel magnetic head used in a 174-inch cartridge type MT device. , 8
There are fixed multi-element magnetic heads such as channel type magnetic heads, and multi-track magnetic heads such as 18-track and 24-track magnetic heads in which the magnetic head is moved up and down relative to the width of the magnetic tape in one or two channels. A two-channel magnetic head is shown as a typical example and will be explained below. That is, 41, 4
1' is a magnetic core for reading, 42.42' is a magnetic core for writing, and 43.43' is a magnetic core for erasing. When the magnetic tape running direction is forward, this magnetic head erases the signal recorded on the magnetic tape with one erase magnetic core 43, records the signal with the write magnetic core 42, and further erases the signal recorded on the magnetic tape with the read magnetic core 41. and play that signal. Furthermore, during rewinding, a method is used in which the other magnetic cores 43', 42', and 41' erase, write, and read signals. Also, 44°44' is the reading magnetic core 41.4
1' is the shield plate, 45 is the center shield plate,
And 46°46' is the write magnetic core 42.42'
The shield plate prevents magnetic flux from leaking from each core and gap. Further, 47 is a deep gutter.

Conventionally, these magnetic heads were used in the state shown in Figures 5 and 6, but as magnetic tapes began to run at higher speeds, the front surface of the magnetic head wore out and the static electrical characteristics changed. Not only this, but also the dynamic electromagnetic characteristics change in a short period of time, and for this reason, a method of welding ceramics to the front surface of the magnetic head has come to be used. For example, as disclosed in Japanese Patent Publication No. 55-14842, Co-Mo
There is a method of plasma spraying -3i-Cr.

FIG. 7 shows a partially enlarged sectional view of the case where ceramic is welded to the front surface of the magnetic head as shown in FIGS. 5 and 6. In FIG. 7, 51 is an I-shaped core, 52 is a C-shaped core, 53 is a fixed frame for the I-shaped core, and 54 is a fixed frame for the C-shaped core. Further, 55 is a magnetic gap into which a gear core spacer made of a predetermined specific magnetic material is inserted.

These are integrated by screwing from one side of the C-shaped core fixing frame 54, and then the front surface of the magnetic head is first ground into a predetermined shape 56. Ceramic welding 57 is then performed on the surface, followed by secondary grinding into a final shape 58.

To explain in more detail about ceramic 'Fg bonding, M
In the magnetic head used in the T device, if the magnetic head has a flux gate, ceramic welding is generally performed directly on the primary grinding surface.

And wear resistance was improved by welding ceramic.

Here, the function of the flux gate 61 will be explained based on FIG. That is, on the front surface of the magnetic head, the magnetic tape 62 contacts the writing magnetic gap 63, the reading magnetic gap 64, and the outriggers 65 on both sides.
A flux gate 61 is arranged in front of it. Now, when recording a signal, the magnetic flux from the write magnetic gap 63 is recorded on the magnetic tape and simultaneously leaks through the magnetic tape. This leakage magnetic flux is absorbed by the flux gate 61.9 The magnetic material 61a in this flux gate 61 is generally Mn-Zn ferrite, and the non-magnetic material 61b is a copper plate, and the base 61clP magnetic material is used for mounting. It is composed of materials,
The leakage magnetic flux will be absorbed by the magnetic material.

In addition, the space S between the front surface of the magnetic head and the flux gate 61 is adjusted and fixed at 0.2 normal position, and the space S
is large, so the absorbed magnetic flux no longer affects the read magnetic gap 64. That is, the connection from the write magnetic gap 63 to the read magnetic gap 164,
In other words, the feedthrough will be absorbed.

Problems to be Solved by the Invention As mentioned above, magnetic heads using ceramic ff1W have the problem of requiring a flux gate due to leakage magnetic flux, which increases manufacturing costs.

In other words, because the ceramic is welded directly onto the processed surface of the front surface of the magnetic head, it is possible to eliminate crosstalk from the write head to the print head, that is, feedthrough, which occurs when the magnetic core is not sufficiently grounded. First, it was impossible to remove the flux gate on the front surface of the magnetic head.

Therefore, an object of the present invention is to provide a magnetic head that can solve the above problems.

Means for Solving the Problems In order to solve the above problems, the magnetic head of the present invention forms a magnetic tape contact surface parallel to the magnetic gap and having a predetermined width on both sides of the magnetic gap, and a portion of this contact surface 0.2 to 0.3 rt over a predetermined range on the front surface of the magnetic head, except for
A thin copper film layer with a thickness of m is provided, and a superconducting material is further deposited on top of the thin film layer by plasma spraying.

Effect: According to the above configuration, since the superconducting material is deposited over a predetermined area on the front surface of the head by plasma spraying, all of the magnetic cores are grounded, and the magnetic properties can be improved without providing a flux gate. can. In addition, due to the difference in linear expansion coefficient between the magnetic core and the superconducting material, distortion will occur in the magnetic core, but since a thin layer of copper is provided between the magnetic core and the superconducting material, the thin layer of copper The layer absorbs the strain and provides a double grounding structure for the magnetic core.

Furthermore, the Meissner effect, which is another feature of superconducting materials, blocks the influence of external magnetic fields on the magnetic head.

EXAMPLE Hereinafter, an example of the present invention will be explained based on FIGS. 1 to 3.

In FIGS. 1 and 2, reference numeral 1 denotes a 172-inch, 9-track magnetic head, in which a write head 2 and a read head 3 are integrated in a sandwich-like manner with a center shield plate 4 interposed therebetween. The above writing head 2 is
11 write magnetic cores (two at both ends are dummies) 5 and intertrack shield plates 6 and 5 interposed between these write magnetic cores 5. It is composed of a writing side fixing frame 8 that is fixed so that a writing magnetic core 17 of a predetermined length is formed. In addition, the read head 3 also has the same functions as described above.
Eleven reading magnetic cores 9, an intertrack shield plate 10 interposed between these reading magnetic cores 9, and a reading magnetic gap 11 of a predetermined length are formed between these magnetic cores 9 and shield plates 10. The read-out side fixing frame 12 is fixed in such a manner that the read-out side fixing frame 12 is fixed in a fixed manner. In addition, each of the magnetic cores 5.9 is a C-shaped core 5a, 9a, respectively.
and I-shaped cores 5b and 9b (second
The writing magnetic gap 7 and the reading magnetic gap 11 are exposed on the surface with a width of approximately 0.4 mm, so that they come into close contact with the magnetic tape when the magnetic tape runs. . Further, a dark copper plating layer (
A copper thin film layer 13.14 is provided, and a ceramic superconducting material is plasma sprayed on the surface of the copper plating layer 13.14 to provide a 12-metal resistance layer 15.16.

To explain in more detail below, each C-shaped core 5
a. Fixed frame 3a for QaeC type core.

A C-shaped core block on the read head side and a write head side fixed to 12a is made, and I-shaped cores 5b and 9b are similarly fixed to the I-shaped core fixing frame 8b.

I-shaped core blocks on the read head side and the write head side fixed to 12b are made, and both these I-shaped core blocks are integrated with each other via the center shield plate 4. Next, a read gap spacer made of a predetermined non-magnetic material is inserted on the read head side to form a continuous magnetic gap 11, and a write gap spacer made of a predetermined non-magnetic material is similarly inserted on the write head side. are inserted to form a write magnetic gap 7, and they are fixed together.

Next, after forming an attachment surface for copper plating by primary grinding, another plating is performed to form another plating layer 13, 14. Next, by secondary grinding, the copper plating layer 13.14
is uniformly processed to a thickness of about 0.2 to 0.3 nm, and then a ceramic superconducting material is welded using a low-temperature plasma spraying device to form wear-resistant layers 15 and 16. And the third
The final shape is then finished by grinding. Further, 17 is an outrigger. This function guides the tape so that the magnetic tape has a constant wrapping angle with respect to the magnetic gap, and since the magnetic tape always runs in contact with a constant tension, wear resistance is required. Ru. For this purpose, a ceramic superconducting material is welded.

This will be explained in more detail based on FIG.

In other words, in order to prevent ceramic particles from colliding with the magnetic core surface at high temperatures and high speeds, the magnetic head is in a state that is completed in the primary grinding process in order to prevent deterioration due to distortion of the magnetic core surface due to differences in linear expansion coefficients. The magnetic core width at 7.11 is ±0.2 t around the magnetic gap.
The magnetic core is processed leaving a processed portion t at the tip so that xm, that is, ρ = 0.4, and a copper plating layer 13 is placed on top of it.
．． Apply 14. After the secondary grinding of the copper plating layer 13.14, a ceramic superconducting material is welded by low temperature plasma spraying (approximately 950° C.).In this way, the copper plating layer 13.14 is deposited on the surface of the magnetic core 5°9. 14 is formed, the difference in linear expansion coefficient from the magnetic cores 5 and 9 is small.
Furthermore, since the wear-resistant layer 15.16 is formed by low-temperature plasma spraying of a ceramic superconducting material on the copper plating layer 13.14, no strain is imparted to the magnetic core 5.9. In the tertiary grinding, the magnetic cores 5, 9 and the magnetic gap are processed to a removal depth T of the magnetic gap 7.11, including the converted portion of the surface of the magnetic cores 5, 9 generated by low-temperature plasma spraying. Both parts 7 and 11 do not cause deterioration of magnetic properties. Note that while the conventional plasma spraying temperature is about 1400° C., in this embodiment it is 950° C., so that the surface alteration of the magnetic cores 5 and 9 is reduced, and the deterioration of the magnetic properties is alleviated.

Next, an embodiment of the pond will be described based on FIG. 4.

This is a two-channel magnetic head used in a 174-inch cartridge-type MT device, and is subjected to primary grinding and copper plating NJ (not shown) in the same way as the 172-inch magnetic head, followed by secondary grinding. After processing, a ceramic superconducting material is welded to form wear-resistant layers 15 and 16, and then tertiary grinding is performed to finish.

Furthermore, in addition to the above (not shown), various magnetic heads for M'I'' devices such as those using cassettes (magnetic tape width 0.15 inches), 1 inch tape width, 2 inch tape width, etc. applicable and these are all 172
You can get the same effect as inches.

Effects of the Invention According to the above configuration of the present invention, since the H conductive material is deposited over a predetermined area on the front surface of the head by plasma spraying,
All the magnetic cores are grounded, and the magnetic properties can be improved without the need for a flux gate. In addition, the strain that occurs in the magnetic core due to the difference in linear expansion coefficient between the magnetic core and the superconducting material is absorbed by the copper thin film layer, so there is no problem.Furthermore, the Meissner effect of the superconducting material causes The influence of external magnetic fields can be blocked.

[Brief explanation of the drawing]

FIG. 1 is a perspective view of a magnetic head in one embodiment of the present invention, FIGS. 2 and 3 are enlarged sectional views of essential parts of the same magnetic head, and FIG. 4 is a perspective view of a magnetic head in another embodiment. Figure 5~f! 88 shows a conventional example, FIG. 5 is a perspective view of a beam track type magnetic head, FIG. 6 is a perspective view of a two-channel magnetic head used in a 174-inch cartridge type magnetic tape device, and FIGS. FIG. 8 is an enlarged sectional view of the main part of the magnetic head. 1...Magnetic head, 2...Writing head, 3...
・Reading head, 7...Writing magnetic gap, 1
1... Magnetic gap for reading, 13.14... Copper plating layer, 15°16... Wear-resistant layer. Agent Yoshihiro Morimoto! Figure 2 Figure f3. Ill ・3 Same Me 4, 14 15, ltp ° 1 Thickness 1 Layer Figure 5 Figure 6 Figure 4 Figure 3 Figure 5.9 Figure 4 Figure 7 Figure 3

Claims (1)

[Claims] 1. A magnetic tape contact surface of a predetermined width is formed parallel to the magnetic gap and on both sides of the magnetic gap, and the width is 0.2 to 0.3 over a predetermined range of the front surface of the magnetic head, excluding the contact surface portion.
A magnetic head in which a thin film layer of copper with a thickness of mm is provided, and a superconducting material is further welded on top of it by plasma spraying.