JPH064826A - Magnetic head - Google Patents

Abstract

PURPOSE:To provide a magnetic head excellent in bonding strength and satisfactory recording and reproducing characteristics. CONSTITUTION:When grooves 11, 12 applied for winding to be a coil are formed in two core halves 10a, 10b of a magnetic head to be joined to each other to obtain a magnetic head, the grooves 11, 12 are formed so that the parts nearest to the sliding face have different positions in the two core halves 10a, 10b after joining and the difference in level is made in the apex of a winding window 13.

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 more particularly to a magnetic head in a magnetic recording / reproducing apparatus such as a VTR or FDD.

[0002]

2. Description of the Related Art Conventionally, a head core 1 which constitutes this type of magnetic head has been constructed as shown in FIG. In this head core 1, a single metal magnetic film or a magnetic layer 6 in which a metal magnetic film and an insulating film are alternately laminated is provided on a non-magnetic substrate 2a by a thin film forming method, and another magnetic layer 6 is further provided on this magnetic layer 6. It was configured by bonding the non-magnetic substrate 2b with glass or the like.

The head core 1 having such a structure has a winding window portion in a state where a pair of magnetic head core halves 1a and 1b processed and formed as shown in FIG. 8 are butted as shown in FIG. 7. Mold glass is placed in the core reinforcing groove 7 and the core reinforcing groove 8 and melted to melt the two magnetic head core halves 1a, 1
It is obtained by joining b.

In the conventional example shown in FIG. 7, the winding window portion 7 in which the winding is finally made to be a coil in the head core is constituted by a groove portion formed on each joint surface side of the magnetic head core half body. However, as disclosed in, for example, Japanese Patent Laid-Open No. 2-46513, there is a winding window portion formed only on one half of the magnetic head core.

However, as the size of the apparatus advances, the magnetic head itself is naturally required to be downsized. Along with this, the dimensions of the magnetic head are also designed to be smaller than before, but the required number of turns of the coil winding is specified by the inductance of the magnetic head. Does not decrease so much.
Therefore, the size of the winding window portion is smaller than that of other dimensions, and the proportion of the winding window portion in the entire magnetic head core tends to be large.

Without being aware of such a situation, a structural design such that the winding window portion is provided only in one of the magnetic head core halves, as shown in Japanese Unexamined Patent Publication No. 2-46513, mentioned above. By doing so, most of the magnetic head core half on the side where the winding window is provided is occupied by the winding window, and the cross-sectional area through which the magnetic flux passes becomes extremely small. This not only means that the core efficiency of the magnetic head itself is reduced and the desired performance is not obtained, but the ratio of the number of windings that can be distributed by the ratio of the cross-sectional areas is such that the magnetic head core half body side provided with the winding window part It becomes very large, resulting in a problem that most of the windings have to be applied to the magnetic head core half on one side. Therefore, when designing a smaller magnetic head, it is desirable to divide the winding window portion into two magnetic head core halves as shown in FIG. 7 to suppress a decrease in core efficiency.

In the conventional head core 1 in which the winding window portion is divided into two magnetic head core halves, as shown in FIG.
As shown in FIG. 0, the mold glass 3 is melted and flows to the apex of the winding window portion (hereinafter referred to as the A-pex portion), and the two magnetic head core halves are joined. The mold glass 3 is generally selected to have good wettability with the substrate. Therefore, the contact angle between the mold glass and the substrate is very small. Therefore, as shown in FIG. The portion is formed with an extremely small angle and spread, and the shape of the glass edge portion becomes a hyperbola which is convex in the A-pex direction due to surface tension.

At this time, the mold glass directly involved in the joining of the two magnetic head core halves is A- in FIG.
Most of the mold glass is in the range of A, that is, A-pex to the apex of the hyperbola, and the bonding strength of this portion is determined by the cross-sectional area of the mold glass involved in this bonding.

[0009]

However, although the molten glass spreads because of the good wettability of the mold glass with respect to the substrate, AA is increased and the glass cross-sectional area involved in bonding is increased. It is difficult to improve the bonding strength. In order to increase A-A, it is necessary to increase the amount of mold glass used and to fill the portion of the winding window portion near the sliding surface with mold glass. The range is limited, and a large effect cannot be obtained. In conclusion, it can be said that it is difficult for the magnetic head having this structure to have a high bonding strength in the A-pex portion.

Further, since the grooves for winding the two magnetic head core halves joined to each other are provided, the cross-sectional area of the magnetic layer in the magnetic gap portion is small in any of the magnetic head core halves. Therefore, the magnetic gap portion is easily magnetically saturated.

An object of the present invention is to solve the above-mentioned problems relating to the bonding strength and the two problems that the magnetic gap portion is apt to be saturated, and it is excellent in strength and is easy to saturate the magnetic gap portion. It is to provide a magnetic head that solves the above problem.

[0012]

According to the present invention, a magnetic layer formed of a single metal magnetic film or a magnetic layer formed by alternately laminating a plurality of metal magnetic films and insulating films is formed as a thin film on a substrate. For forming a magnetic head core shape after forming a film by the method, and providing a magnetic gap portion, and in a magnetic head formed by joining the head cores with glass, for providing windings provided on the magnetic head core halves joined together Is characterized in that the portion of the groove closest to the sliding surface is processed to have different positions in the two magnetic head core halves after joining, and a step is provided in the A-pex portion of the winding window.

[0013]

According to the magnetic head of the present invention, while the region for the winding is stably secured in the winding window portion, the joining cross-sectional area by the mold glass in this portion is increased to enhance the joining strength and the magnetic gap. Suppression of part saturation is suppressed to the extent that head performance is not affected.

[0014]

The magnetic head of the present invention will be described in more detail below with reference to the embodiments shown in the drawings. FIG. 1 shows the first of the present invention.
FIG. 6 is an enlarged view of a winding window portion of the head core constituting the magnetic head according to the example of FIG. In FIG. 1, reference numerals 10a and 10b denote magnetic head core halves joined to each other, and 10 denotes the entire head core.
Reference numerals 1 and 12 are grooves provided in the respective magnetic head core halves 10a and 10b to form the winding window portion 13. FIG. 2 shows the winding window portions 13 of the two magnetic head core halves 10a and 10b before the mold glass 3 is melted, and the head core 10 shown in FIG. 1 is formed by heat-treating the winding window portions 13.

In the head core 10 according to the first embodiment, the winding groove 1 in one magnetic head core half 10a is used.
1 is formed so as to be shifted downward with respect to the winding groove 12 in the other magnetic head core half 10b in FIG.
Therefore, the facing surface viewed from the A-pex portion of the winding groove 12 is not the inclined surface as shown in the conventional example but the bonding surface itself. The angle θ formed by and is half that in the conventional example.

At this time, as a matter of course, the contact angle between the substrate and the mold glass is the same as in the case of the conventional example, and the surface tension of the mold glass is also unchanged. It becomes as shown in 1. That is, since the angle is halved, the spread of the mold glass can be suppressed, the glass can be filled in the A-pex portion, and the height from the A-pex to the apex of the hyperbola, which has been a problem in the conventional example, can be achieved. The cross-sectional area of the mold glass which is directly involved in the bonding shown is increased and therefore the bonding strength is improved.

In the magnetic head core half 10a on the side having the winding groove 11, the winding window portion 13 is lowered downward in the figure to increase the cross-sectional area of the magnetic layer portion near the gap as compared with the conventional one, and the other side. Saturation is less likely to occur than in the vicinity of the gap in the magnetic head core half 10b. Also, the head core 1
Since the gap depth of 0 is defined by the A-pex portion of the winding groove 12, the same value as in the conventional case can be given. Here, from the principle of magnetic recording, it is widely known that recording by a magnetic head is determined by the trailing edge side when viewed from the direction of travel of the magnetic gap. By disposing the magnetic head core half body 10a having 11 on the rear side with respect to the head traveling direction, it is possible to obtain a magnetic head having an excellent recording and reproducing ability as compared with the conventional example.

FIG. 3 is an enlarged view of the winding window portion of the head core constituting the magnetic head according to the second embodiment of the present invention, as viewed from the side surface of the head core. In FIG. 3, 2
0a and 20b are magnetic head core halves joined to each other,
Reference numeral 20 denotes the entire head core, and reference numerals 21 and 22 denote winding window portions 2.
Each magnetic head core half 20 to form three
It is a groove provided in a and 20b. The difference between the second embodiment and the first embodiment is that the deviation of the winding grooves 21, 22 is large. FIG. 4 shows two magnetic head core halves 20a, 20b before the mold glass 3 is melted.
3 shows the winding window portion 23 of FIG. 3, and the head core 20 shown in FIG. 3 is formed by heat-treating the winding window portion 23.

In the head core 20 according to the second embodiment, the winding groove 2 in one magnetic head core half 20a is used.
1 is a winding groove 2 in the other magnetic head core half 20b
Similar to the first embodiment, it is displaced downward with respect to No. 2, and the amount of displacement is larger than that in the first embodiment. Therefore, the mold glass 3 after joining is in the step created by this displacement.

As a result, the spread of the mold glass 3 becomes small as shown in FIG. 3, but the improvement of the bonding strength due to this is obtained as in the first embodiment. Moreover, since the mold glass 3 is inside the step, the bonding strength can be further improved. Explaining the reason for this, in the first embodiment, the mold glass 3 protrudes from the step, so that a discontinuous place is formed on the edge of the mold glass 3 at a position corresponding to the apex of the winding groove 11.

At such a discontinuity, stress from the outside is likely to be concentrated, which easily causes a fracture of the joint surface. On the other hand, in the second embodiment, since all the mold glasses 3 are contained in the step, it is possible to realize a perfect hyperbolic shape without producing discontinuities at the mold glass edges. It is expected that the bonding strength will be higher than that of the first embodiment.

Further, the cross-sectional area of the magnetic layer in the gap portion of the magnetic head core half 20a including the winding groove 21 becomes wider than that of the first embodiment due to the large deviation of the winding groove. By disposing the half body 20a rearward in the head traveling direction, it is possible to provide a magnetic head having further excellent recording / reproducing efficiency for the same reason as the case shown in the first embodiment.

FIG. 5 is an enlarged view of the winding window portion of the head core constituting the magnetic head according to the third embodiment of the present invention, as viewed from the side surface of the head core. In FIG. 5, 3
0a and 30b are magnetic head core halves joined to each other,
Reference numeral 30 indicates the entire head core, and reference numerals 31 and 32 indicate the winding window portion 3.
Each magnetic head core half 30 to form three
It is a groove provided in a and 30b. The magnetic head of the third embodiment is different from the second embodiment in that the head core differs from the second embodiment in that the winding groove shift amount is the same, but the side surface of the winding groove 31 on the side closer to the head sliding surface is the joint surface. It has an angle of 90 degrees with respect to. FIG. 6 shows the winding window portions 33 of the two magnetic head core halves 30a and 30b before the mold glass is melted, and the head core 30 shown in FIG. 5 is formed by heat-treating the winding window portions 33.

In the head core 30 of the magnetic head according to the third embodiment, the side surface near the sliding surface side of the winding groove 31 in one magnetic head core half 30a is 90 degrees with respect to the joint surface. Winding window portion 3 in comparison with the second embodiment
3 can be effectively wide, and the coil can be wound closer to the gap, and the efficiency of the head can be improved.

Also, the cross-sectional area of the magnetic layer in the gap portion is the second
In the same manner as in the first and second embodiments, recording is performed by arranging the magnetic head core half 30a on the side having the winding groove 31 rearward with respect to the head traveling direction, as in the first and second embodiments. It is also possible to obtain a magnetic head excellent in terms of reproduction characteristics.

At this time, it is desirable that the molded glass 3 after bonding is present only inside the step for the same reason as shown in the second embodiment, but compared with the conventional example, the glass cross-sectional area of the bonded portion is Is significantly increased, and even if the mold glass 3 is present in a portion other than the step, the effect of considerably improving the bonding strength can be obtained.

In the third embodiment described above, the side surface of the winding groove farther from the sliding surface is located at the same position after joining the two magnetic head core halves 30a and 30b. However, this side surface does not need to be particularly in the same position, and as a matter of course, deviation can be allowed within a range in which the winding region is not unnecessarily narrowed. In addition, although the present invention has described a laminated alloy film type magnetic head as one example thereof, a so-called metal using a ferrite as a back core is provided with an alloy film having a high saturation magnetic flux density only in the vicinity of the magnetic gap. It goes without saying that the same effect can be obtained with an in-gap (MIG) type magnetic head.

Next, the bonding strength and recording / reproducing characteristics of the magnetic head according to the present invention and the conventional magnetic head will be concretely compared. Table 1 shows the results of comparison of the bonding strength between the magnetic head according to the conventional example and the magnetic head according to the example of the present invention. The bonding strength was measured by the bonding strength evaluation tester shown in FIG. 11, and the bonding strength was simply expressed by the load when the head core broke. Figure 1 showing this tester
In FIG. 1, reference numeral 40 denotes the entire testing machine, 41 is a load cell (load converter), 42 is a head core support, 43 is a head core pressing jig, and 44 is a moving mechanism for applying a load.

Further, in Table 1, the bonding strength is simply expressed by the load when the magnetic head chip is broken.
In the table, the third embodiment (1) indicates that after the bonding, a part of the mold glass protrudes from the step of the A-pex part.
In Example (2), all of the mold glass after bonding is A-
The case where it is inside the pex section is shown. In any of the examples, the mold glass was PbO-TeO ₂ -B ₂ O ₃ -Al.
_A composition having a composition of ₂ O ₃ —ZnO—ZrO _{2 having} a transition point of 355 ° C., a softening point of 429 ° C. and a working temperature of 516 ° C. was used.

[0030]

Table 2 shows the results of comparison of the self-recording / reproducing output at 1 MHz measured by the head-only evaluation machine of the magnetic head according to the conventional example and the magnetic head according to the example of the present invention. However, the output of the conventional magnetic head at 1 MHz was set to 0 dB.

[0032]

As a result of the above, as shown in the embodiment of the present invention, the portion of the groove for winding provided on the magnetic head core halves to be joined to each other that is closest to the sliding surface is the two magnetic head cores after joining. A magnetic head core half body in which the A-pex portion of the winding window is processed to have different positions in the half body to form a step and the groove closest to the sliding surface of the groove provided for winding is opposed. The magnetic head core half located at a position farther from the sliding surface than the portion closest to the sliding surface of the groove for winding at is placed behind the other magnetic head core half in the head traveling direction. It can be seen that, by adopting the above, the recording medium has excellent bonding strength and good recording and reproducing characteristics as compared with the conventional example.

[0034]

As described above, according to the magnetic head of the present invention, the winding windows for forming the winding window portions, which are respectively formed in the two magnetic head core halves, are formed in a staggered manner, and the stepped portion thereof is formed. By arranging the mold glass for bonding in, the bonding strength can be improved and good recording / reproducing characteristics can be obtained. Further, according to the magnetic head of the present invention, since the molding glass for bonding is made to exist in the step of the shifted winding groove, higher bonding strength can be expected and the recording / reproducing efficiency can be improved. It will be even better. Further, according to the magnetic head of the present invention, since the two side surfaces of the groove for forming the winding formed on one of the magnetic head core halves are both 90 degrees with respect to the joint surface, The window can be effectively widened, and the coil can be wound closer to the gap, so that the efficiency of the magnetic head can be improved.

[Brief description of drawings]

FIG. 1 is a side view of a winding window portion in a head core that constitutes a magnetic head according to a first embodiment of the present invention.

FIG. 2 is a side view showing a winding window portion in the head core shown in FIG. 1 in a state before joining the core halves.

FIG. 3 is a side view of a winding window portion in a head core forming a magnetic head according to a second embodiment of the present invention.

FIG. 4 is a side view showing a winding window portion in the head core shown in FIG. 3 in a state before joining the core halves.

FIG. 5 is a side view of a winding window portion in a head core forming a magnetic head according to a third embodiment of the invention.

6 is a side view showing a winding window portion in the head core shown in FIG. 5 in a state before joining the core halves.

FIG. 7 is a perspective view showing an example of a head core forming a conventional magnetic head.

8 is a perspective view showing a pair of magnetic head core halves constituting the head core shown in FIG. 7 in a state before joining.

FIG. 9 is a side view showing the head core in the figure before being joined by a glass mold.

FIG. 10 is an enlarged side view showing a winding window portion of a head core forming a conventional magnetic head.

FIG. 11 is a structural explanatory view schematically showing a testing machine for evaluating the bonding strength of a magnetic head.

[Explanation of symbols]

 3 bonding glass 10 head core 10a magnetic head core half body 10b magnetic head core half body 11 winding groove 12 winding groove 13 winding window portion

Claims (3)

[Claims] 1. A magnetic layer formed of a single metal magnetic film or a magnetic layer formed by alternately laminating a plurality of metal magnetic films and insulating films is formed on a substrate by a thin film forming method,
After processing this into a magnetic head core shape, a magnetic gap portion is provided, and in a magnetic head in which the head cores are joined by glass, in order to apply windings that will become coils to both of the two magnetic head core halves that are joined together. And a portion of the groove closest to the head sliding surface is located at different positions in the two magnetic head core halves after joining. 2. A magnetic layer formed of a single metal magnetic film or a magnetic layer formed by alternately laminating a plurality of metal magnetic films and insulating films on a substrate by a thin film forming method,
After processing this into a magnetic head core shape, a magnetic gap portion is provided, and in a magnetic head in which the head cores are joined by glass, in order to apply windings that will become coils to both of the two magnetic head core halves that are joined together. Groove is formed, and the portion of this groove closest to the head sliding surface is located at a different position in the two magnetic head core halves after bonding, and the bonded glass further connects the windings of the two magnetic head core halves. A magnetic head characterized by being in a step formed in a portion closest to a sliding surface of a groove for applying. 3. A magnetic layer formed of a single metal magnetic film or a magnetic layer formed by alternately laminating a plurality of metal magnetic films and insulating films on a substrate by a thin film forming method,
After processing this into a magnetic head core shape, a magnetic gap portion is provided, and in a magnetic head in which the head cores are joined by glass, in order to apply windings that will become coils to both of the two magnetic head core halves that are joined together. Windings are formed, and the portion of the groove closest to the head sliding surface is located at a different position in the two magnetic head core halves after joining, and the winding formed in either one of the magnetic head core halves. A magnetic head characterized in that the two side surfaces of the groove for applying are 90 degrees with respect to the joint surface.