JPH0261809A - Magnetic head - Google Patents

Abstract

PURPOSE:To easily perform the measurement and management of gap depth by providing a groove whose bottom plane is crossed with the sliding plane of a medium with a prescribed angle and whose length on the sliding plane corresponds to the gap depth at a corner end on one side of the medium sliding plane of a magnetic head core, and filling glass in the groove. CONSTITUTION:The groove 14 is formed at the corner end part of the medium sliding plane 13 of a ferrite core block 11, and an angle theta formed by the bottom of the groove and the plane 13 is set at 5-80 deg.. The glass with a melting point of (450-800 deg.C) is melted and filled in the groove 14. A track regulating groove 16 and a winding groove 17 are formed on a plane 12. Dimension (l) is found by performing the mirror-grinding of the plane 12, and the dimension (d) of the gap depth is computed, then, it is set at prescribed dimension. Also, an SiO2 sputter film with thickness of several thousand Angstrom to 1mum is adhered on the plane 12. By employing such constitution, it is possible to measure the depth of the gap 5 by a microscope in the grinding process of the final plane of the medium sliding plane, and to easily perform the management, therefore, a head with high resolution can be realized with high efficiency.

Description

Detailed Description of the Invention [Sho]'' Jth 11th minute l- The present invention provides a flat medium sliding contact surface used in floppy disk drives, fixed disk drives, etc., and a core for use in sliders, etc., i1! This relates to a magnetic nod sandwiched between plates.

Previously, this type of magnetic head was used in floppy disk drives (hereinafter F
I) A magnetic head for abbreviated as D) is shown in Figure 4 (
As shown in a), a magnetic core 1 is sandwiched between a slider 2 made of ceramic such as calcium titanate, and is bonded to the magnetic core 1, which fills a magnetic gap 3. In the case of a fixed disk drive (hereinafter referred to as HDD), as shown in FIG.
is embedded and welded with low melting point glass 8.

In conventional magnetic heads for FDDs and HDDs, even if you try to determine the gap depth/fill, it will not work as shown in Figure 4 (
It cannot be optically observed or measured because it is obstructed by the sliders 2 and 7 shown in a) and (b).

Here, the gap depth is the size of dO shown in FIG. 4(C), and this figure shows the core 1 in FIG.
- It is a sectional view cut along the A' line. The gap depth usually has a value of 10 μm to 50 μm.

The shallower the gap depth, the higher the recording efficiency, but if it is too shallow, the core near the gap becomes magnetically saturated, resulting in a decrease in recording resolution. According to experiments conducted by the inventors, recording efficiency drops significantly when the gap depth exceeds 15 μm;
Below m, the recording resolution decreases. Therefore, the optimal gap depth is 2 μm to 15 μm. On the other hand, from the viewpoint of wear resistance, a thickness of 2 μm is dangerous, but according to experiments conducted by the inventors, a thickness of 5 μm or more is sufficient.

From the above, the range of gap depth that does not deteriorate recording efficiency or resolution and has good wear resistance is 5 μm to 15 μm. This means that the gap depth tolerance is ±5 μm, which not only requires high-precision machining, but also requires measurement and control of the finished gap depth. .

However, as mentioned above, it has been impossible to measure with conventional methods.

The magnetic head of the present invention has a gap depth measuring groove at both ends or one corner end of the medium sliding surface of the magnetic head core, and the bottom surface of the gap depth measuring groove The groove intersects the sliding surface at an angle of 5° to 80°, and this groove is filled with glass having a melting point of 450° C. to 800° C.

Historically, the length of this gap depth measuring groove on the medium sliding contact surface is characterized by being made to correspond to the gap depth.

Usually, in the FDD or HDD magnetic head shown in FIGS. 4(a) and 4(b), after the slider 2 or 7 is attached to the magnetic rad core 5 or 6, the slider 2 or 7 is bonded to the magnetic core 5 or 6 until a predetermined gap depth is reached. It is completed by flat-polishing the surface that contacts the media. The magnetic head of the present invention also undergoes this process, but in the magnetic head configured as in the present invention, as shown in FIG. 3, which shows a cross section taken along line B-B in FIG. Since the welded glass 10 is transparent, the gap depth can be measured using a microscope, so measure this gap depth dO and the length pO of the gap depth measurement groove on the surface in contact with the medium. Yes. Then, if the angle between the medium sliding contact surface and the bottom surface of this groove is θ, then do = I!Otan (
θ)+C, that is, C=dO−I! 0tan(θ) is found.

Then, by attaching a slider and polishing the medium sliding contact surface to measure the height l of the gap depth measurement groove on the medium sliding contact surface, the gap depth d can be calculated as d=Jtan (θ)+C. become.

Next, embodiments of the present invention will be described with reference to the drawings.

FIGS. 1(a) and 1(b) are perspective views showing one embodiment of the present invention. (a) shows the present invention applied to an FDD magnetic head, and (b) shows the present invention applied to an HDD magnetic head.

1(a) is the core of the magnetic head, which is made of a magnetic material such as MnZn ferrite, and 2 is a slider which is made of ceramic such as calcium titanate. 3 is a groove for measuring the gap depth, and the glass 4
is filled.

The angle θ between the bottom surface of the groove 3 and the medium sliding contact surface 10 is 5a to 80°. There is a gap 5 in the longitudinal center of the magnetic core 1, where a signal magnetic field is recorded on the medium and a signal recorded on the medium is generated.

6 in FIG. 1(b) is a magnetic core, and as in FIG. 1(a), Mn-
Zn ferrite, etc., and 7 is a slider, which is calcium titanate or the like. Similarly to (a), 3 is a groove for measuring the gap depth. Angle θ between the bottom of this groove and the medium sliding surface
is 5″ to 80° as in the same figure (a). Also, the magnetic core 6
is embedded in the slider 7 by welding with glass 8. Further, a gap 9 is provided at the center of the core 6 in the longitudinal direction. The effect of the gap 9 is as described above.

Note that if the angle θ is less than 5 degrees, it is difficult to optically measure the 1st method d, and if it is more than 80', the tolerance accuracy will deteriorate when calculating the dimension l, so the range of the angle θ should be limited. The settings are as described above.

Next, a method for manufacturing a magnetic head according to the present invention will be briefly explained with reference to FIGS. 2(a) to 2(f) for the embodiment shown in FIG. 1(a).

As shown in FIG. 2(a), a Mn--Zn ferrite block 11 is prepared, and a gap depth measuring groove 14 is formed by grinding with a dicer or the like from the corner end on the side surface 13, which will be the surface in contact with the medium. At this time, the angle θ between the bottom surface of the groove and the groove 13 is set to a certain value in the range of 5° to 80°. In addition, 4
If it is set to 5°, the value of jan(θ) described above becomes 1, which facilitates calculation.

Next, this groove is melted and filled with glass having a melting point of 450° C. to 800° C., and the excess glass is scraped off. This ferrite block is turned over, with the ferrite block 12 facing up, and track regulating grooves 16 and winding grooves 17 are formed by grinding with a dicer or the like. This state is shown in the same figure (b).

Thereafter, the abutting surface 12 is polished to a mirror surface using a car surface polishing machine, the dimension l is determined as shown in FIG. 5t02 or the like, which will become the gap spacer 18, is deposited to a thickness of several thousand to 1 μm by sputtering or the like.

Two ferrite plates 19 thus formed are butted together so that the gear and spacer forming surfaces face each other, as shown in FIG.
Insert the glass fiber at °°C to 750°C, heat it and melt it. Thereafter, the ferrite side surface is cut and sliced along the cutting line 21 as shown in FIG. 5(e) to obtain a magnetic rad core 23 as shown in FIG. 4(f).

The magneto-electromagnetic head for FDD, which is an embodiment of the present invention, is shown in FIG. 1(a) in which sliders 2 are attached to both sides of the magnetic core 23.

It is manufactured in the same manner as the magneto-magnetic head for HDD shown in FIG. 1(b).

According to the magnetic head of the present invention, the gap depth can be measured by visual inspection using a microscope during the heavy polishing process, and the gap depth can be easily managed. This not only makes it possible to create a magnetic head with high efficiency and higher resolution, but also improves the reliability of its life due to wear and improves manufacturing yield. It becomes possible to

[Brief explanation of the drawing]

FIG. 1(a) is a perspective view of a magneto-electromagnetic head for FDD which is an embodiment of the present invention. FIG. 2B is a perspective view of a magneto-electromagnetic head for HDD which is another embodiment of the present invention. FIGS. 2(a) to 2(f) are perspective views or plan views showing an example of the method for manufacturing the magnetic head of the present invention. FIG. 3 is a sectional view taken along line B--B of the magnetic head core of the present invention shown in FIG. 1, for explaining the function of the gap measuring groove. FIG. 4(a) is a perspective view showing a conventional FID magnetic head, and FIG. 4(b) is a perspective view showing a conventional HDD magnetic head. ■...Magnetic rad core made of ferromagnetic material, 2...A guard plate (slider made of t-ramic), 3
...F book for gap depth measurement, 4...Glass filling groove for gap depth measurement,
5...Magnetic gap, 6...Magnetic gap made of ferromagnetic material7.7...t
Slider 8...Glass to which the magnetic head core is bonded, 9...Magnetic gap, 10...Welded glass, 11...Ferrite block, 12...Gaff sword cedar surface ferrite profiler
13...Side surface of the ferrite block serving as a medium sliding contact surface, 14...Gap depth claw determining groove, 15...Glass filled in the gap depth measuring groove,
6...Track regulation groove, 7...Winding groove, 8...Gearfbusbe number, 9...Magnetic Hefdkoabrofke half-break, 0...Glass fiber, l, 22...Cutting line, 3... Magnetic head core assembly. (a) (b) Miniature drawing (α) (b) lK1 Drawing procedure amendment (method) December 1988 Patent application No. 213148 Title of invention 11 related patent applications by those who correct magnetic heads 2-9-1 Seiran, Otsu City, Shiga Prefecture, 520 Kansai Exit Hondenki Co., Ltd. "Brief explanation of drawings" column of the revised specification. The content of the correction, page 10, line 5, "This is a perspective view."
Ir

Claims (2)

[Claims] (1) A magnetic head in which the medium sliding contact surface of the core is flat and the core is sandwiched between protective plates, characterized in that a groove for measuring the depth of the magnetic gap is provided in at least one corner end of the core. magnetic head. (2) The magnetic head according to claim 1, wherein the bottom surface of the magnetic gap measurement groove intersects the medium sliding surface at an inclination of 5° to 80°.