JPS5927986B2 - floating head - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a medium floating head that positions a recording/reproducing head to a flexible magnetic recording medium such as a tape or a floppy disk to a minute and constant gap.

More directly, the present invention relates to a floating tape head that can reliably scan down to submicron gaps in a rotating head magnetic tape recording device. Conventionally, in this type of tape floating head, as shown in FIG. 1, the opposing surface of the head block 1 that faces the magnetic tape is formed into a spherical or pseudo-spherical surface, and recording is performed near the apex of this spherical or pseudo-spherical surface. A reproduction gap 2 is formed, and a spherical tape is formed on both sides of the recording/reproduction gap 2 in the relative traveling direction of the head (hereinafter also referred to as the head traveling direction).

), two grooves 4, 4 were provided so that a central land portion 3 and a side land portion 6 were formed on the opposing surfaces from the front end to the rear end. In this grooved spherical surface, if the width of the central land 3 sandwiched between the two grooves is 250 to 300 μm, the rear end of the central land 3 in the direction of head movement is 1 to 1.5 mm from the apex of the central land. .1～
A minimum gap of 0.15 μm is created, and a uniform gap of 0.3 to 0.5 μm is formed over a wide area near the apex. Therefore, by providing the recording/reproducing gap 2 in this uniform gap area, the track width can be increased from 250 to 300 mm.
pm) It was possible to realize a tape floating head with a flying clearance of 0.3 to 0.5 μm. However, in this type of head, there is a local minimum clearance between the front and rear parts of the air bearing surface in the direction of head movement, and the width of the central land portion 3 is reduced by 2.
If it is less than 00 μm, the tape and head will come into contact at the minimum gap position, which is not suitable for narrowing tracks and making minute gaps. i.e. track width 200
In the case of a narrow track head of less than .mu.m, the magnetic core must be embedded in the central land portion, which increases the processing cost. On the other hand, in order to minimize the gap in the recording/reproducing gap while maintaining high reliability, it is desirable to provide the recording/reproducing gap at the minimum gap position. However, since the minimum gap area is narrow and its position moves due to variations in scanning conditions, it has not been possible to provide the recording/reproducing gap at the minimum gap position. In contrast, the distance from the spherical apex to the rear end in the direction of head movement is shortened to about 1 mm, and a minimum gap is forcibly created at the rear end of the central land in the direction of head movement, which is smaller than the width of the central land. A grooved spherical head of the type shown in Fig. 2 which forms a recording/reproducing gap of track width was disclosed in a patent application filed in 1983-1983.
No. 470.

In FIG. 2, the same elements as those shown in FIG. 1 are given the same reference numerals. Further, in FIG. 2, numeral 7 is a winding core, 8 is a winding, and 9 is the apex of the air bearing surface of the head block. In this type of head, as shown in FIG. 3 by an equal gap curve 11 of the tape floating gap, a minimum gap occurs at the rear end of the central land portion 3 in the direction in which the head travels. Therefore, compared to the head type shown in Figure 1, this type of head has a recording/reproducing gap 2 at the minimum gap position.
It also has the advantage that a recording/reproducing gap with a narrow track width can be formed relatively easily. However, the operating margin against variations in scanning conditions such as tape tension, the amount of push of the head into the tape, the shape and setting position of the head, etc., was not necessarily large, and there were still problems with its reliability. The reason for this is that because the tape floating pressure generated in the central land portion 3 is small, the floating gap region of 0.5 μm or less becomes unnecessarily long from the apex of the spherical surface to the front in the direction of head movement, and the tape in the recording/reproducing gap portion The floating clearance became too small to 0.1 μm or less. Furthermore, since the distance between the apex of the spherical surface and the recording/reproducing gap portion is short, about 1 mm, the tape deforms rapidly at the rear end in the direction of movement of the head, making it easy for the head and tape to come into contact. If the width of the central land portion 3 is increased in order to increase the floating pressure of the tape on the central land surface, the gap at the center of the land surface will increase, causing the problem that the floating gap of the land portion will become uneven along the width direction. was. Also, in this head,
The drawback was that the track width could not be set to a desired width without affecting the flying characteristics. The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a floating head that eliminates the drawbacks of the conventional heads described above, in which the surface facing the flexible recording medium is spherical or In the floating medium head having a pseudo-spherical surface, a recording/reproducing gap is formed at the rear end in the direction of movement of the head relative to the flexible recording medium on the opposing surface, and The recording medium partially forms two grooves extending forward in the relative traveling direction from the trailing edge in the relative traveling direction, the tips of which are closed within the opposing surface, and forming a head for the flexible recording medium on the opposing surface. spaced apart by a desired track width on both sides of the portion where the recording/reproducing gap is formed at the rear end in the relative traveling direction of the recording/reproducing gap;
2 which is inclined so as to become deeper toward the rear in the direction of relative movement of the head with respect to the flexible recording medium on the opposing surface.
It is characterized by the formation of book-slanted grooves.

The drawings will be described in detail below.

FIG. 4 shows an embodiment of the present invention, in which reference numeral 1 indicates a head block, and 2 indicates a head block formed at the rear end of the surface of the head block 1 facing the magnetic tape (flexible recording medium) in the direction in which the head travels. Recording/reproducing gap, 3 is a central land portion, 4a is a partial groove extending from the rear edge of the opposing surface in the direction of head movement forward along the same direction, and whose tip is closed within the opposing surface to control the flying gap. , 6 is a side land portion, 7 is a winding core, 8 is a winding wire, 9 is an apex of the air bearing surface of the head block, 10 is spaced apart by a desired track width on both sides of the portion where the recording/reproducing gap 2 is formed; and two inclined grooves which are inclined so as to become deeper toward the rear in the head traveling direction on the opposing surfaces,
This is an inclined groove for forming the track width of the recording/reproducing gap 2 provided at the rear end of the opposing surface in the direction of head movement.

In the following explanation, the words front end, rear end, trailing edge, front, and rear mean the front end, rear end, It means trailing edge, front, and rear. The surface of the head block 1 facing the magnetic tape has a radius of curvature so that floating pressure is generated between the magnetic tape and the facing surface by the principle of air bearing by pushing this facing surface into the magnetic tape surface by several tens of μm and scanning. It is a spherical or pseudo-spherical surface of 15 to 25 mm.

Although the air bearing surface is divided into a central land portion 3 and a side land portion 6 by two partial grooves 4a, they are continuous in front of the air bearing surface, which is a feature of the present invention that is different from the conventional one. Such a partial groove 4a open at the rear end of the air bearing surface can be easily formed by tilting the rear end of the head block 1 so as to lift it and moving the groove grinding wheel horizontally. The length of the two partial grooves 4a is 1 to 3.5 mu
Appropriately, the groove width is from several tens of micrometers to a hundred and several tens of micrometers, and the groove depth is approximately 200 to 300 micrometers at the rear end of the air bearing surface.

Also, the width of the central land portion 3 is 200 to 400! Approximately Tm is appropriate, and the optimum values of these parameters depend on head scanning conditions and physical constants of the magnetic tape. Various known methods can be used to form the recording/reproducing gap 2 at the rear end of the central land portion 3.

In the embodiment shown in FIG. 4, a recording/reproducing gap is formed by glass-bonding two magnetic core blocks with processed gap parts and winding parts, and after processing the air bearing surface into a spherical shape,
An example is shown in which the winding core and track width are formed by grinding. In particular, the method of forming track widths with high precision by machining grooves that are inclined about 30 degrees with respect to the air bearing surface is new. FIG. 6 shows details of the cross section along the inclined groove 10. The length l and width b of the inclined groove 10 from the gap on the air bearing surface are preferably small in order to prevent a drop in flying pressure in the vicinity of the recording/reproducing gap, and both are preferably 100 μm or less.

On the other hand, from the viewpoint of electromagnetic conversion characteristics, the edge shape of the inclined groove 10 is straight at the recording/reproducing gap part, and in front thereof, it becomes a smooth arc in order to suppress crosstalk due to the pseudo gap effect of the groove edge. It is desirable to be present. For example, if you use a grinding wheel with a thickness of 80 μm and an inclination angle of 30 μm,
For example, if the groove is machined to l-100 ttm, a parallel groove will be formed up to 20 μm in front of the gap, and a semi-elliptical groove edge with a major diameter of 80 μm will be formed in front of the parallel groove. The groove depth at the recording/reproducing gap portion is 50 μm or more, and the angle between the air bearing surface at the tip of the groove and the groove wall is as large as 1500, so the pseudo gap effect at these positions is significantly reduced. When the floating head constructed as described above is used as a rotary scanning head, an equal gap distribution as shown in FIG. 7 is obtained on the floating surface.

That is, in the groove-free area in front of the air-bearing surface, it is several μm or more, similar to the spherical surface without grooves, and decreases monotonically from near the tip of the groove to the rear, reaching a minimum value at the recording/reproducing gap position. As you can see by comparing Figure 7 and Figure 3,
The air bearing clearance in the area in front of the air bearing surface has increased, and the submicron minute gap area is limited to the area behind the air bearing surface. Also, since a long narrow gap region is formed on the air bearing surface,
High floating pressure is generated behind the central land portion 3. Therefore, it is possible to increase the pushing amount of the head into the tape, and the stiffness of the air film near the recording/reproducing gap 2 is also increased, so that the floating gap at the recording/reproducing gap 2 position is not affected by fluctuations in the head scanning conditions. A floating head can be realized. As the length of the partial groove 4a from the rear end is increased, the floating clearance distribution in FIG. 7 gradually approaches that in FIG. 3. At the same time, the pressure generated on the air bearing surface also decreases, so that the gap in the recording/reproducing gap becomes less than 0.1 μm. On the other hand, when the length of the groove 4a is shortened, the interval between the equal gap lines 11 in FIG. 7 becomes smaller, and the gap at the rear end of the central land portion 3 rapidly decreases. This means that the tape in the recording/reproducing gap section 2 is undergoing rapid deformation, and the possibility that the tape will come into contact with the air bearing surface of the winding core 7 increases. Therefore, the length of the partial groove 4a is 1 to 3,51L as described above.
A value of about m is appropriate. Another advantage of the floating head of the present invention is that the distance from the apex 9 of the air bearing surface to the position of the recording/reproducing gap 2 is 1.5 to 2.5 mm compared to the conventional head shown in FIG.
It is possible to grow it to the size of a small fish. This is because as the tape in front of the floating surface is lifted, the minimum clearance position moves backwards, which significantly reduces the probability of damaging the recording/playback gap area when setting or adjusting the floating head. I can do it. Still another advantage of the present invention is that the size of the minimum clearance can be adjusted by appropriately selecting the length and width of the partial groove 4a and the width of the central land portion 3.
It is possible to set the desired value in the range of 0.05 to 0.5 μm.

Generally, by decreasing the length of the partial grooves 4a, decreasing the groove radius, and increasing the width of the central land portion 3, the distance from the apex 9 to the recording/reproducing gap 2 can be increased, and at the same time, the value of the minimum gap can also be increased. However, the groove width and the center land width cannot be changed independently, and in order to make the flying clearance in the land width direction near the recording/reproducing gap uniform, it is necessary to reduce the groove width as the center land width increases. In the width scanning rotating head mechanism, the head scanning radius is 35 mm and the head curvature radius is 20 mm.
m7! According to experiments in the case of L, in order to make the minimum clearance of the recording/reproducing gap part 0.15 to 0.2 μm, the central land width should be 300 μm when the head scanning speed is 44 m/s.
Appropriately, the length of the one-part groove was 2.5 mm, the width was about 80 ttm, and the distance from the top of the air bearing surface to the recording/reproducing gap was about 1.7 mm.

On the other hand, when the head scanning speed was 55 m/s, the appropriate width of the central land was 300 .mu.m, the length of the partial groove was 3 mm, the width was about 100 .mu.m, and the distance between the top of the air bearing surface and the recording/reproducing gap was 2 m. As described above, in the present invention, the flying characteristics are mainly determined by the partial grooves 4a, and the flying clearance is not affected by variations in head scanning conditions.

In the present invention, an inclined groove 10 is provided to form the track width of the recording/reproducing gap 2. Providing the inclined grooves 10 in addition to the partial grooves 4a has the advantage that an arbitrary track width can be set without affecting the flying characteristics. As explained above, the floating head of the present invention generates a high tape floating pressure on the air bearing surface of the head, and causes the floating surface to exert pressure on the flexible recording medium. It is possible to form a wedge-shaped flying clearance that slowly increases forward in the direction of movement until the rear end of the head in the direction of relative movement of the head reaches a desired minimum clearance, and Since it is possible to easily and accurately form a recording/reproducing gap with a narrow track width at the minimum clearance position at the rear end, it is possible to easily and accurately form a recording/reproducing gap with a narrow track width.
It can be used as a floating head for high-density recording with a narrow track width.

Further, at the rear end in the head traveling direction of the surface facing the flexible recording medium, a desired track width is provided on both sides of the portion where the recording/reproducing gap is formed, and at the rear end of the facing surface in the head traveling direction. Since the two inclined grooves are formed so as to become deeper toward the surface, an arbitrary track width can be set without affecting the flying characteristics. The floating head of the present invention can be used not only as a rotational scanning head in the width direction and diagonal direction, but also as a floating head for a flexible magnetic disk to obtain similar effects.

[Brief explanation of drawings]

Figure 1 is an external view of a conventional grooved spherical head, Figure 2 is an external view of another type of conventional grooved spherical head, and Figure 3 is the same clearance as the tape flying clearance on the flying surface of the head shown in Figure 2. 4 is an external view of the floating head of the present invention, FIG. 5 is an enlarged top view of the recording/reproducing gap portion of FIG. 4, FIG. 6 is an enlarged sectional view thereof, and FIG. This is the equal gap line distribution of the floating clearance of the floating head. 1...Head block, 2...Record/playback gap, 3...Central land portion, 4...
... Groove, 4a ... Partial groove, 6 ... Side land part, 7 ... Winding core, 8 ... - ...
Winding wire, 9...Apex of air bearing surface, 10...Incline groove, 11...Equal clearance line.

Claims (1)

[Claims] 1. In a floating medium head in which the surface facing a flexible recording medium is a spherical or pseudo-spherical surface, a recording/reproducing gap is formed at the rear end of the facing surface in the direction of movement of the head relative to the flexible recording medium. , and partially form two grooves extending forward in the direction of movement of the head relative to the flexible recording medium on the opposing surface and whose tips are closed within the opposing surface. and a desired track width on both sides of the portion where the recording/reproducing gap is formed at the rear end portion of the opposing surface in the direction of relative movement of the head with respect to the flexible recording medium; 1. A floating head comprising two inclined grooves which are inclined to become deeper toward the rear in the direction of movement of the head relative to a flexible recording medium.