JPS6128163B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a magnetic head that minimizes deformation due to wear on the tape sliding surface and maintains initial electromagnetic conversion characteristics for a long time.

When a magnetic head is used for a long time, the tape sliding surface of the magnetic head gradually wears out due to friction with the magnetic tape, and the electromagnetic conversion characteristics of the magnetic head in the high frequency range begin to deteriorate. Then, as the wear progresses further, the electromagnetic conversion characteristics deteriorate over the entire frequency band.

Traditionally, permalloy has been mainly used as the core material for magnetic heads, but in order to solve the above-mentioned wear problem, cores made of more wear-resistant materials such as hard permalloy, ferrite, and sendust have been used. A magnetic head was developed. However, a fixing material that is injected inside the magnetic head and used to hold the core, a shielding material that shields leakage magnetic flux from adjacent cores, magnetically insulating the core and the shielding material, and improving track position accuracy. The improving spacing plate also constitutes a sliding surface with the tape. Therefore, in order to maintain the electromagnetic conversion characteristics of a magnetic head for a long time at the initial stage of use, the core, the fixing material, the blocking material, and the spacing plate must be worn equally, and the tape sliding surface must be kept flat at all times. Therefore, it is necessary to consider the balance of wear. Generally, the fixing material is epoxy resin with filler such as SiO ₂ added, the blocking material is hard permalloy, and the spacing plate is phosphor bronze (Cu-
Sn-P alloy) or nickel silver (Cu-Ni-Zn alloy)
are using.

The characteristics required of the spacer plate include good malleability, non-magnetic material, good electrical conductivity, and excellent corrosion resistance.

The above-mentioned good ductility is required because the thickness of the spacer plate needs to be accurate in order to improve the positional accuracy of the track.

The non-magnetic material is required to prevent a magnetic short circuit between the core (for example, hard permalloy) and the blocking plate (for example, hard permalloy).

The good electrical conductivity is required in order to increase the eddy current loss in the blocking plate and the spacing plate, thereby increasing the leakage magnetic flux shielding effect.

The above-mentioned good corrosion resistance is required because the spacer plate is exposed to the tape sliding portion and exposed to the outside air.

FIG. 1A is a sideways front view of a general magnetic head (including the present invention since it has no difference in appearance), and 1 and 1' are cores having gaps 1a and 1'a; 2 is a fixing member that fixes the cores 1 and 1' to a case 5, which will be described later; 3 is a shielding plate (shielding member) that magnetically shields the cores 1 and 1'; and 4 and 4' are shielding plates 3.
and a spacing plate (separation member) that separates the cores 1 and 1' from each other;
This is a case that covers the spacer plates 4, 4', etc. 1st
In the magnetic head of Figure A, the magnetic tape 6 shown by the dashed line runs in the direction of the arrow 7,
Information is recorded or read in portions a and 1'a.

FIG. 1B is an enlarged sectional view of the magnetic head shown in FIG. 1A taken along dashed lines a and b before a wear test.

In Figure 2, hard permalloy material is used for cores 1-1 and 1'-1, hard permalloy material is used for shielding plate 3-1, and nickel silver is used for spacer plates 4-1 and 4'-1. In conventional magnetic heads, the tape speed
This is a cross-sectional view after an abrasion test in which a magnetic tape (not shown) was fed at a speed of 4.75 cm/S for 200 hours (the vertical dimension is enlarged 50 times the horizontal dimension to show the state of wear). In FIG. 2, spacer plates 4-1,
The 4'-1 part is convex due to less wear.
The tape sliding surface is uneven.

In this way, when unevenness occurs on the tape sliding surface and the wear condition becomes as shown in FIG. 2, the contact condition between the magnetic tape (not shown) and the cores 1-1 and 1'-1 deteriorates. Due to so-called spacing loss, electromagnetic conversion characteristics generally deteriorate, including in the high frequency range.
Then, as shown by curve 11 in the wear time vs. output characteristic in FIG. 5, the output decreases with wear.
Moreover, cassette tapes have a tape pad built into the cassette, and the flexible magnetic tape is pressed onto the magnetic head by the tape pad, so the wear on the cores 1-1 and 1'-1 can progress to a considerable depth. , the surface irregularities become more noticeable over time. Therefore, before the cores 1-1, 1'-1 reach their wear limit, the electromagnetic conversion characteristics will deteriorate significantly due to the unevenness of the tape sliding surface. The present invention provides a magnetic head that eliminates the above-mentioned drawbacks, and uses a Cu--Al alloy containing at least Cu (copper) and Al (aluminum) as the spacing plate. In addition to Cu and Al, if necessary, Pb (lead), Se (selenium), Te (tellurium), Mn
(manganese) is added. Hereinafter, the specific content and effects of the present invention will be explained with reference to the drawings.

The graph in FIG. 3 shows how the spread rate (broken line 8) and the amount of wear (solid line 9) of the spacer plates change when Al is added to Cu.

According to this, it can be seen that when Cu contains 20% or more of Al, it loses its malleability and cannot be processed into a thin plate. Furthermore, when Al in Cu becomes 2% or less, the amount of wear on the spacer plate (solid line 9) becomes less than the amount of wear on the magnetic core and shield plate using hard permalloy material (range 10 shown by diagonal lines). The degree of wear is not much different from that of the spacer plates used in conventional magnetic heads. Therefore, by containing 2% to 20% of Al in Cu, the amount of wear and ductility can be made suitable for the spacer plate. The above Al content is the value when only Al is contained in Cu, but in reality, Pb, Se, Te, Mn are added for the purpose of improving various properties (for example, workability) of the spacer plate. may be added. Therefore, Cu vs. Al is 98% vs. 2%
The ratio is set between 80% and 20%, that is, between 49:1 and 4:1, and the above-mentioned Pb, Se, Te, and Mn are added to this. Therefore, the spacing plate used in the magnetic head of the present invention is made of at least Cu and Al,
Cu:Al was set between 49:1 and 4:1. Further, it can cause the same amount of wear as the core, etc., and maintain the initial electromagnetic conversion characteristics for a long time.

Next, we will discuss the effects.

Figure 4 A is 0.2mm for core 1-2, 1'-2.
A layer of three thick hard permalloy materials is used, the hard permalloy material is used as the shielding plate 3-2, and the material of the spacer plate is Cu-95%, Al-5%.
This is a magnetic head according to the first embodiment of the present invention using a Cu-Al alloy, and this magnetic head was cut along the dashed-dotted lines a and b shown in FIG. 200 magnetic tapes (not shown)
It is an enlarged cross-sectional view after a wear test carried out over a period of time (the vertical dimension is enlarged 50 times the horizontal dimension).

According to this, the cores 1-2, 1'-2 and the spacers 4-2, 4'-2 are worn out almost uniformly, and as shown by curve 12 in the graph of FIG. It wasn't much different than before the test.

Figure 4B is 0.2mm for core 1-3, 1'-3.
Hard permalloy material is used as the shielding plate 3-3, and the material of the spacer plate is Cu-94%, Al-5% (Cu:Al=
18.8:1), Pb-1% alloy according to the second embodiment of the present invention, and this magnetic head is cut along the dashed-dotted lines a and b shown in FIG. , is an enlarged cross-sectional view after a wear test in which a magnetic tape (not shown) was run at a tape speed of 4.75 cm/S for 200 hours (the vertical dimension is enlarged 50 times the horizontal dimension). Even with this, core 1-3, 1'
-3 and spacer plates 4-3 and 4'-3 were worn almost uniformly, and a result roughly equal to curve 12 shown in the graph of Figure 5 was obtained, and the output was not much different from before the wear test. . Furthermore, in the second embodiment, Pb
The content of Se is 0-5%, and Se,
Contains 0 to 5% of each of Te and Mn (Pb, Se,
Te, Mn can be any combination, each 0 to 5%
The minimum is Pb + Se + Te +
When Mn=0% to a maximum of Pb+Se+Te+Mn=20%), the processability is particularly improved and the manufacturing of the spacer plate becomes easy. at this time
Cu:Al shall be between 49:1 and 4:1.

As described above, the spacer plate used in the magnetic head of the present invention is made of a Cu--Al alloy containing at least Cu and Al, and the core and the spacer plate wear to the same extent. Therefore, even if wear occurs due to tape running, the tape sliding surfaces between the core and the spacing plate will wear uniformly and surface irregularities can be kept to a minimum, so spacing loss will not occur. Therefore, good electromagnetic conversion characteristics can be maintained until the core reaches its wear limit.

[Brief explanation of the drawing]

Figure 1A is a front view of a typical magnetic head;
Figure B is an enlarged sectional view of the magnetic head in Figure 1A before the wear test, Figure 2 is an enlarged sectional view of the conventional magnetic head after the wear test, and Figure 3 shows the amount of wear and spread rate of the spacer plate. FIG. 4A shows a cross-sectional view of the magnetic head according to the first embodiment of the present invention after a wear test, and FIG. 4B shows a cross-sectional view of the magnetic head according to the second embodiment of the present invention after a wear test.
FIG. 5 shows the wear time vs. output characteristics of the conventional magnetic head and the magnetic head of the present invention. In each figure, 1, 1-1, 1-2, 1-3, 1', 1'-1,
1'-2, 1'-3 are magnetic cores, 2, 2-1, 2-
2, 2-3 are fixing materials, 3, 3-1, 3-2, 3-
3 is a shielding plate, 4 and 4' are general (including the present invention)
4-1, 4'-1 are conventional spacing plates, 4
-2, 4'-2 is the spacing plate of the first embodiment of the present invention, 4
-3, 4'-3 is a spacing plate of the second embodiment of the present invention, 5
is the case.

Claims (1)

[Claims] 1. a plurality of magnetic head elements each having a magnetic core made of a hard permalloy material that slides on a recording medium; a shielding member made of a hard permalloy material provided between the magnetic cores of the plurality of magnetic head elements to shield leakage magnetic flux; An isolating member is provided between the shielding member and the magnetic core to isolate the shielding member and the magnetic core, and the isolating member is made of Cu having a Cu:Al ratio of 49:1 to 4:1. :A magnetic head characterized by being composed of an Al alloy.