JPH07121824A - Magnetic head device - Google Patents

Abstract

PURPOSE:To improve reliability of a product by making gap length of an eras ing gap the prescribed value or less by a track width controlling groove pro vided at only one side of a magnet ic core. CONSTITUTION:This device is constituted with a head 1 for recording and reproducing being a first magnetic head element and a head 3 for erasing being a second magnetic head element formed with this head 1 and a center glass 2. In the head 1, a recording and reproducing gap g1 is formed by opposing each end plane of two recording and reproducing cores 4, 5. The head 3 for erasing is positioned behind the head 1, each end planes 6a, 6b and 7a, 7b of a core 6 for erasing having no track groove and connected to the center glass 2 and a core 7 having a track groove are respectively opposed and erasing gaps g2, g3 are formed. By making gap length of these gap g2, g3 3mum or less respectively, when a erasing current is induced by the head 3 for erasing, magnetic field generated at gaps g2, g3 are kept within a range of a track width (d), fringing becomes such quantity that it does not influence actually.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic head device mounted on a magnetic disk drive device, etc.
The present invention relates to a magnetic head device in which a writing head and an erasing head are connected and formed.

[0002]

2. Description of the Related Art For example, a disk-shaped magnetic disk such as a floppy disk is relatively easy to handle and is capable of recording a large-capacity signal.
The range of use is being expanded as an external storage device such as a word processor.

In a floppy disk drive (hereinafter, simply referred to as FDD), data is recorded with a track width somewhat narrower than a track pitch in order to guarantee data compatibility. In fact, for example, in a 48 TPI FDD, the track width used for data is about 60% of the track pitch, and the remaining portion is a portion called data called a guard band from which data is erased.

In the magnetic head device of this FDD, only the recording / reproducing head is sufficient if there is no off-track, but in reality, the magnetic head always has some off-track with respect to the track center. Even if there is such an off-track, a magnetic head in which an erasing head is arranged adjacent to the recording / reproducing head in order to guarantee a guard band by trim erase that erases unnecessary data between data Is usually used.

In a magnetic head device having such an erasing head, a pair of erasing magnetic gaps are arranged on both rear sides of the recording / reproducing magnetic gap, and even when there is an off-track, the recording track and the recording track are separated from each other. A so-called tunnel erase type magnetic head (hereinafter referred to as a tunnel erase head) of a type that guarantees a space is widely used.

As this tunnel erase head, two types of erasing heads having different forms are known. First, as shown in FIG. 8, the first mold is composed of a recording / reproducing head 101 and an erasing head 103 formed via the recording / reproducing head 101 and the center glass 102.

In the recording / reproducing head 101, two recording / reproducing cores 104 and 105 are provided on the respective end faces 104a and 105.
The recording and reproducing gap g11 is formed by abutting a. Further, the erasing head 103 is located behind the recording / reproducing head 101 as viewed from the rotation direction of the disk indicated by the arrow M in the figure, and the two erasing cores 106.
End faces 106a and 106 each having two two
b and 107a and 107b are brought into contact with each other to form two erase gaps g12 and g13.

On the other hand, the second type has substantially the same structure and function as the first type, but as shown in FIG. 9, an erasing head which is a constituent element of this tunnel erase head. 108, an erasing core 109 having no track groove and an erasing core 110 having a track groove have end faces 109a and 109b, 110a and 1 respectively.
Two erase gaps g
14 and g15 are different in that they are formed and configured.

In the second type tunnel erase head, the work of making two erasing cores in contact with each other to form an erasing gap at the time of fabrication is much easier than that of the first type. However, it is often used as a magnetic head device for FDD because the cost is significantly reduced.

[0010]

However, while the second type tunnel erase head is very easy to manufacture and is low in cost as described above, the erase head 108 of this tunnel erase head is used for erasing. When inducing a current, as shown in FIG. 10, fringing exceeds the track width t of the end faces 110a and 110b of the erasing core 110, which is the range to which the magnetic fields generated in the erasing gaps g14 and g15 should be originally applied. There is a problem that a leakage magnetic flux that spreads to the left and right is generated at s, and therefore data is erased more than necessary.

At present, various countermeasures have been devised to cope with this problem, but the countermeasures which make it possible to sufficiently exhibit the characteristics of the trim erase of the tunnel erase head of the second type. The current situation is that there is no.

The present invention has been made in view of the above problems, and an object of the present invention is to erase on an erasing head manufactured by abutting a core having no track groove and a core having a track groove. It is possible to suppress the leakage flux generated when inducing a current to an appropriate value and sufficiently guarantee the characteristics as an erasing head, and increase the yield at low cost without degrading product quality. Another object of the present invention is to provide a magnetic head device capable of significantly improving the reliability of the product.

[0013]

According to the present invention, there is provided a first magnetic head element having a magnetic gap for recording and reproduction, and an erase gap for erasing both end portions of a recording track written by the first magnetic head element. 2. The track width of the erase gap of the second magnetic head element is regulated by a track width regulating groove provided only on one magnetic core, and the gap length is set to 3. It is formed and configured to have a thickness of 0 μm or less.

Further, according to the present invention, there is provided a first magnetic head element having a magnetic gap for recording and reproduction, and a second magnetic head element having an erase gap for erasing both end portions of a recording track written by the first magnetic head element. And the erasing current (mA) supplied to the coil of the second magnetic head element and the number of turns (T) of the coil of the erasing head are 680 mA · T or less. To be configured.

[0015]

In the magnetic head device according to the present invention, the erasing gap length of the second magnetic head element having the erasing gap for erasing both end portions of the recording track, which is a component thereof, is set to a small value of 3.0 μm. As a result, the spread of the magnetic flux of the magnetic field generated in the erase gap when inducing the erase current in the second magnetic head element is almost within the track width, and the leakage magnetic flux expanding beyond the track width can be practically ignored. It will be reduced to the extent that it can be obtained.

Further, in the magnetic head device according to the present invention, an erasing current (mA) induced in the second magnetic head element, which is a component of the magnetic head device and has an erasing gap for erasing both end portions of the recording track, By setting the product of the number of turns (T) of the coil of the erasing head to be 680 mA · T or less, the erasing gap is generated when the erasing current is supplied to the coil of the second magnetic head element. The strength of the magnetic field is reduced and the spread of the magnetic flux falls within the track width. Therefore, the leakage magnetic flux expanding beyond this track width is reduced to a level that can be practically ignored.

[0017]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Some embodiments of a magnetic head device according to the present invention will be described below with reference to the drawings.

First, in the magnetic head device according to the first embodiment, as shown in FIG. 1, a recording / reproducing head 1 which is a first magnetic head element, and this recording / reproducing head 1
And an erasing head 3 which is a second magnetic head element formed through the center glass 2.

The recording / reproducing head 1 is constituted by two recording / reproducing cores 4 and 5 having their respective end faces 4a and 5a butted together to form a recording / reproducing gap g1.

The erasing head 3 is located behind the recording / reproducing head 1 as viewed from the direction of rotation of the disk indicated by arrow M in the figure, and does not have a track groove connected to the center glass 2. The erasing core 6 which is the first core and the erasing core 7 which is the second core having the track groove are brought into contact with their respective end faces 6a and 6b and 7a and 7b, respectively, and two erasing gaps g2 and g3 is formed (hereinafter, the erasing head having this structure is simply referred to as an H-type head).

Here, the gap length d of each of the two erase gaps g2 and g3 is set to be 3.0 μm or less.

Here, one experimental example will be shown. In this experimental example, for the magnetic head device according to the first embodiment and the conventional magnetic head device shown in FIG. 8, an erasing current and a coil induced in the erasing head 3 and the erasing head 103 which are H-shaped heads. The number of turns is set to 5.2 mA and 175 T for both erasing heads, and the above-mentioned leakage flux when the gap lengths d and w (μm) of the erasing gaps g2, g3 and g12, g13 of these erasing heads are changed. This is an examination of a change in fringing (μm), which is the spread width of.

As a result of this experimental example, as shown in FIG. 2, as the gap length increases, the fringing occurring in the erasing head 3 becomes larger than the fringing occurring in the erasing head 103. Recognize. However, by setting the gap lengths of the erasing gaps g2 and g3 of the erasing head 3 to 3 μm or less, the fringing generated in the erasing head 3 is approximately the same as the fringing occurring in the erasing head 103. And is considered to be negligible in practice.

That is, by setting the gap lengths of the erase gaps g2 and g3 to 3 μm or less, in the erase head 3, the erase gaps g2 and g3 are induced when the erase current is induced, as shown in FIG. The magnetic field generated at 1 is substantially within the range of the track width d, which is the range to which the magnetic field is originally applied, and the fringing s has such an amount that it has no practical effect.

In the magnetic head device according to the first embodiment, the erasing head 3 which is a component of the second magnetic head element having the erasing gaps g2 and g3 for erasing both end portions of the recording track is provided. By setting the erase gap length to a small value of 3.0 μm, the erase gaps g2 and g can be reduced when the erase current is induced in the erase head 3.
The spread of the magnetic flux of the magnetic field generated in No. 3 is almost contained in the track width, and the leakage flux spreading beyond the track width is reduced to a practically negligible level.

Therefore, it is possible to realize a tunnel erase type magnetic head which does not deteriorate the characteristics of the erasing head by using the H type head which is very easy to manufacture.
It is possible to significantly improve the product yield and reliability.

Next, some modifications of the first embodiment will be described with reference to the drawings. The same reference numerals are given to those corresponding to FIG.

First, a first modification is shown in FIG. This first modified example has a structure similar to that of the first example, but the erasing head 8 is a first core having a track groove connected to the center glass 2 and is an erasing core. 9 and an erasing core 10, which is a second core having no track groove, are abutted at each end face 9a and 9b and 10a and 10b to form erasing gaps g2 and g3. .

Also in this first modification, the erase gaps g2 and g3 are each formed to have a gap length of 3.0 μm or less, as in the first embodiment.

Similarly to the first embodiment, the first modified example is a second magnetic head element having its constituent erase gaps g2 and g3 for erasing both end portions of the recording track. By setting the erase gap length of the erase head 8 to a small value of 3.0 μm, when the erase current is induced in the erase head 8, the erase gap g
The spread of the magnetic flux of the magnetic field generated in 2 and g3 is substantially contained in the track width, and the leakage flux spreading beyond the track width is reduced to a practically negligible level.

Therefore, a tunnel erase type magnetic head which does not deteriorate the characteristics of the erasing head can be realized by using the H type head which is very easy to manufacture.
It is possible to significantly improve the product yield and reliability.

Next, a second modification is shown in FIG. The second modified example has substantially the same configuration as the first example, but does not have a center glass between the recording / reproducing head 1 and the erasing head 11, and these two heads are connected and integrally formed. It is different in that it is done. Also in this second modification, the erase gaps g2 and g3 are each formed to have a gap length of 3.0 μm or less, as in the first embodiment.

Similarly to the first embodiment, the second modified example is a second magnetic head element having the erase gaps g2 and g3 that are the constituent elements of the recording track and erase both end portions of the recording track. By setting the erasing gap length of the erasing head 11 to a small value of 3.0 μm, the spread of the magnetic flux of the magnetic field generated in the erasing gaps g2 and g3 when inducing the erasing current in the erasing head 11 is made almost uniform. The leakage magnetic flux which is contained in the track width and expands beyond the track width is reduced to a practically negligible level.

Therefore, it becomes possible to realize a tunnel erase type magnetic head which does not deteriorate the characteristics of the erasing head by using the H type head which is very easy to manufacture.
It is possible to significantly improve the product yield and reliability.

Next, FIG. 6 shows a third modification. The third modified example has substantially the same structure as the first modified example, but does not have a center glass between the recording / reproducing head 1 and the erasing head 8, and these two heads are connected and integrated. It is different in that it is formed. Also in this third modification, the erase gaps g2 and g3 are each formed to have a gap length of 3.0 μm or less, as in the first embodiment.

Similarly to the first embodiment, the third modification is a second magnetic head element having its constituent erase gaps g2 and g3 for erasing both end portions of the recording track. By setting the erase gap length of the erase head 8 to a small value of 3.0 μm, when the erase current is induced in the erase head 8, the erase gap g
The spread of the magnetic flux of the magnetic field generated in 2 and g3 is substantially contained in the track width, and the leakage flux spreading beyond the track width is reduced to a practically negligible level.

Therefore, it becomes possible to realize a tunnel erase type magnetic head which does not deteriorate the characteristics of the erasing head by using the H type head which is very easy to manufacture.
It is possible to significantly improve the product yield and reliability.

Next, a magnetic head device according to the second embodiment will be described. The same reference numerals are given to those corresponding to FIG.

The magnetic head device according to the second embodiment is
Although the structure is almost the same as that of the first embodiment, the erase heads 3 have erase gaps g2 and g3 each having a gap length of 3.5 μm, which is the same as the current gap length.
The erasing current (m
The difference is that the product of A) and the number of turns (T) of the coil of the erasing head 3 is 680 mA · T or less.

Here, one experimental example will be shown. In this experimental example, for the magnetic head device according to the second embodiment and the conventional magnetic head device shown in FIG. 8, the gap length of the erasing head 3 and the erasing head 103, which are H-shaped heads, and the number of turns of the coil. 3.5 μm for both heads
And 175T, and the ratio (%) of the amount of magnetic flux contained in the track width t of the erasing head 3 and the erasing head 103 when the erasing current (mA) supplied to the coils of these erasing heads is changed. I investigated the change of.

As a result of this experimental example, as shown in FIG. 7, as the erasing current increases, the ratio of the amount of magnetic flux contained in the track width t of the erasing head 3 becomes that of the erasing head 103. It can be seen that the amount is reduced, that is, fringing is increased in comparison. However, the erase current is about 4.3 mA (that is, 4.3 mA x shown by a broken line in the figure).
175 T to 680 mA · T) or less, the ratio of the amount of magnetic flux contained in the track width t of the erasing head 3 is approximately the same as that of the erasing head 103, and this difference Is considered to be negligible in practice.

In the magnetic head device according to the second embodiment, the constituent element of the erasing head 3 is the second magnetic head element having the erasing gaps g2 and g3 for erasing both end portions of the recording track. By erasing the coil of the erasing head 3 by setting the product of the erasing current (mA) supplied to the coil and the number of turns (T) of the coil of the erasing head 3 to 680 mA · T or less. When the current is supplied, the strength of the magnetic field generated in the erase gap becomes small, and the spread of the magnetic flux falls within the track width. Therefore, the leakage magnetic flux expanding beyond this track width is reduced to a level that can be practically ignored.

Therefore, similarly to the first embodiment, a tunnel erase type magnetic head which does not deteriorate the characteristics of the erasing head can be realized by using the H type head which is very easy to manufacture. It is possible to significantly improve the product yield and reliability.

[0044]

According to the magnetic head device of the present invention,
A first magnetic head element having a recording / reproducing magnetic gap and a second magnetic head element having an erase gap for erasing both end portions of a recording track written by the first magnetic head element are integrally formed. Since the track width of the erase gap of the second magnetic head element is regulated by the track width regulating groove provided only on one magnetic core and the gap length is formed to be 3.0 μm or less, the track groove is formed. Sufficient characteristics as an erasing head are achieved by suppressing the leakage flux generated when an erasing current is induced in an erasing head made by assembling a core that does not have and a core that has a track groove to an appropriate value. It becomes possible to guarantee, increase yield at low cost without lowering product quality, and significantly improve product reliability.

Further, according to the magnetic head device of the present invention, the first magnetic head element having a magnetic gap for recording and reproduction and the both end portions of the recording track written by the first magnetic head element are erased. A second magnetic head element having an erase gap for
Erase current (m
Since the product of A) and the number of turns (T) of the coil of the erasing head is 680 mA · T or less, the core having no track groove and the core having the track groove are made by butting each other. The leakage flux generated when inducing an erase current in the erase head can be suppressed to an appropriate value, and the characteristics of the erase head can be sufficiently ensured. The yield can be increased at a cost, and the reliability of the product can be significantly improved.

[Brief description of drawings]

FIG. 1 is a plan view schematically showing a configuration of a magnetic head device according to a first embodiment.

FIG. 2 is a characteristic diagram showing a relationship between a gap length of each erasing head and fringing in the magnetic head device according to the first embodiment and the conventional magnetic head device.

FIG. 3 is a plan view schematically showing a state of magnetic flux of a magnetic field generated in an erasing gap of an erasing head which is a constituent element of the magnetic head device according to the first embodiment.

FIG. 4 is a plan view schematically showing the configuration of a first modification of the magnetic head device according to the first embodiment.

FIG. 5 is a plan view schematically showing a configuration of a second modification of the magnetic head device according to the first embodiment.

FIG. 6 is a plan view schematically showing a configuration of a third modification of the magnetic head device according to the first embodiment.

FIG. 7 is a graph showing an erase current induced in each erasing head of the magnetic head device according to the first embodiment and a conventional magnetic head device, and a magnetic flux amount within a track width for a magnetic field generated in an erasing gap. It is a characteristic view which shows the relationship with a ratio.

FIG. 8 is a plan view schematically showing a configuration of a conventional first type tunnel erase type magnetic head.

FIG. 9 is a plan view schematically showing a configuration of a conventional second type tunnel erase type magnetic head.

FIG. 10 is a plan view schematically showing a state of magnetic flux of a magnetic field generated in an erasing gap of an erasing head which is a constituent element of a conventional second type tunnel erase type magnetic head.

[Explanation of symbols]

 1 ... Recording / reproducing head 2 ... Center glass 3 ... Erase head 4, 5 ... Recording / reproducing core 6, 7 ... Erase core

Claims (2)

[Claims] 1. A first magnetic recording / reproducing magnetic gap
And a second magnetic head element having an erasing gap for erasing both end portions of the recording track written by the first magnetic head element. The magnetic head device is characterized in that the track width of the erasing gap is restricted by a track width restricting groove provided only on one magnetic core, and the gap length is 3.0 μm or less. 2. A first magnetic recording / reproducing magnetic gap.
And a second magnetic head element having an erasing gap for erasing both end portions of the recording track written by the first magnetic head element. The magnetic head device is characterized in that the product of the erase current (mA) supplied to the coil and the number of turns (T) of the coil of the erase head is 680 mA · T or less.