Dynamic magnetic information storage or retrieval – Fluid bearing head support – Disk record
Reexamination Certificate
1998-12-03
2001-01-16
Evans, Jefferson (Department: 2754)
Dynamic magnetic information storage or retrieval
Fluid bearing head support
Disk record
C360S234800, C360S121000
Reexamination Certificate
active
06175473
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a magnetic head which is subjected to an air stream on a recording medium in a floating position or slides on a recording medium, and more particularly to a magnetic head in which a core assembly having a magnetic gap is mounted on a rail formed on a slider.
2. Description of the Related Art
In a magnetic head being subjected to an air stream on a recording medium in a floating position, a rail having a predetermined width is formed on opposing surfaces of a slider and a recording medium to form an ABS surface (air bearing surface) on the rail which is subjected to an air stream.
In a disk apparatus, for example, having a flexible disk for high density recording as a recording medium, on the rail surface of the slider, mentioned above, a core assembly formed by joining half-portions of the core across a magnetic gap is mounted thereon. For high density recording, because of a narrow track width, the width of the half-portion of the core forming the core assembly is sufficiently smaller than that of the rail forming the ABS surface.
Therefore, when the core assembly is mounted on the rail of the slider, a slot with a narrower width than that of the rail is to be formed in the rail of the slider to embed the core assembly therein.
The magnetic head of this configuration, however, presents problems as follows.
(1) As it is necessary to form a narrower slot in the rail of the slider than the width of the rail, it is very difficult to machine such a narrow slot, because the slider is as small as 3 mm on one side.
(2) As the core assembly is embedded in the narrow slot formed in the rail of the slider, it is difficult to position and secure the half-portion of the core in the narrow slot. Accordingly, in mounting the core, some problems may be encountered, such as deviation of an azimuth angle of a magnetic gap by inclined mounting of the half-portion of the core in the slot, difficulty in precise positioning of the magnetic gap, and difficulty in precise setting of the depth of the magnetic gap from the surface of the rail (gap depth).
(3) Since the slider and the half-portion of the core are made of materials that are different, their wearing states are different. When the slider is made of a ceramic of calcium titanate (Ti—O—Ca) and the half-portion of the core is made of ferrite, for example, the slider is prone to wear in comparison with the half-portion of the core. In the above-mentioned structure of the core assembly embedded in the surface of the rail with a narrower width than that of the rail, the wearing states differ in the surface of the rail and the half-portion of the core at the portion where the core assembly is mounted. This results in possibility of producing differences in level on the ABS surface (rail surface) in the width direction. The differences in level may affect the floating position of the slider on a recording medium and also may cause possible blemishes of the surface of the recording medium.
SUMMARY OF THE INVENTION
Accordingly, in order to solve the aforementioned problems, it is an object of the present invention to provide a magnetic head in which machining of the slider is easy when the core assembly is placed, and a magnetic gap of the core assembly can be precisely positioned and fixed to the slider, and differences in level in the width direction of the rail on the surface of the ABS can be prevented.
In one aspect of the present invention, a magnetic head comprises a slider; a rail extending in the scanning direction of a recording medium, formed in the slider; a core assembly formed by joining core half-portions which have the same width as that of the rail across a magnetic gap therebetween; and a coil which is placed in the core half-portion, wherein the core assembly is placed into the rail in a continuous position with the rail, and wherein the surface of the rail and the surfaces of the core half-portions are continuous and have the same width.
In the present invention, since the widths of the core half-portions of the core assembly and the rail are the same, a slot in the same width as that of the rail may be machined in the slider, which results in easy machining of the slot. The core assembly also can be easily positioned in the slider and a magnetic gap of the core assembly can be precisely positioned and fixed to the slider, preventing deviation of an azimuth angle.
Since the core assembly is formed in the same width as that of the rail, and the core half-portions of the core assembly form a portion of the rail, in the portion where the core assembly is placed, the rail is formed by only the core half-portions in the rail width direction. Therefore, wearing of the ABS surface around the magnetic gap may be even when sliding on a recording medium which prevents large differences in level in the ABS surface. Particularly, when the core assembly is placed on the trailing side of the slider and the rail in the trailing portion is formed by only the core assembly, the ABS surface which may slide with a recording medium, mostly in a CSS (contact start stop) system is formed by the core material. The wearing of the ABS surface on the trailing side can be prevented by using a wear resistant material as the core material.
In a second aspect of the present invention, a magnetic head comprises a slider; a rail extending in the scanning direction of a recording medium, formed in the side of the slider; a core assembly formed by joining core half-portions across a magnetic gap therebetween; and a coil which is placed in the core half-portion, wherein the core assembly is placed to the side face of the rail, and wherein the surface of the rail and the surfaces of the core half-portions are formed continuously with each other.
Assembling of the core half-portions in the slider may be simple because the core half-portions can be fixed to from the side direction of the slider. Machining of a slot in which the core assembly is fitted may be eliminated.
In this case, it is preferable that the core half-portions of the core assembly be formed in the same width as that of the rail, wherein in the slider, a concave portion is formed by cutting a notch in the rail in the width direction, wherein the core assembly is placed into the concave portion, and wherein the surface of the rail and the surfaces of the core half-portions are formed continuously with each other in the same width.
In this configuration, the wearing of the surface of the rail by the sliding with a recording medium may be even; and a track-width of the magnetic gap of the core assembly may be shorter than the width of the rail according to the present invention.
A magnetic head may comprise an additional rail formed in the slider in parallel with the rail; and an additional core assembly having a magnetic gap with a larger track width than the track width of the core assembly, wherein at least a partial portion of the additional rail is formed by the additional core assembly.
In this configuration, since the surface of each rail is formed by the core half-portions, the wearing on the both rails is even, preventing differences in level in the ABS surface. The entire surface of the ABS will be wear resistant by forming the core half-portions by a wear-resistant material.
The present invention is not limited to a configuration in which the additional rail is formed by the additional core assembly as mentioned above, the additional rail may be formed by the material forming the slider in one piece.
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pa
Alps Electric Co. ,Ltd.
Brinks Hofer Gilson & Lione
Evans Jefferson
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