JPH0435832B2 - - Google Patents

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention is capable of holding a magnetic head and stably facing a recording medium at a predetermined interval to perform good reproduction of the recording medium. This article relates to a highly practical floating head slider.

[Technical background of the invention and its problems]

2. Description of the Related Art Magnetic disk storage devices using so-called hard disks as recording media are often used as large-capacity storage devices for information processing systems. This device rotates a hard disk at high speed while a magnetic head is placed opposite the information recording surface of the hard disk with a small gap therebetween, thereby performing magnetic recording and reproducing of information at high speed. Conventionally, therefore, a floating head slider has been exclusively used to make the magnetic head face the information recording surface of the disk through the minute gap. In this floating head slider, for example, as shown in FIG. 1, a magnetic head 3 is attached to the end of a slider body 2, which has two parallel smooth surfaces 1a and 1b formed on the surface facing the information recording surface. It is something. The smooth surfaces 1a and 1b are provided in the direction of relative movement between the magnetic head 3 and the disk, and the front end thereof, that is, the end opposite to the mounting portion of the magnetic head 3, is cut out to form a pressure booster. The tapered surfaces 4a and 4b are as shown in FIG.

According to the floating head slider holding the magnetic head 3 having such a structure, the second
As shown in FIG. The air compressed through the tapered surfaces 4a and 4b generates a pressure as shown in FIG. 2b as a floating force for the slider. This floating force and the load applied to the slider work together to set a predetermined minute gap between the smooth surfaces 1a, 1b and the information recording surface.

By the way, when performing magnetic recording and reproducing using the magnetic head 3 held by such a floating head slider, the minute gap between the information recording surface and the information recording surface set by the head slider has a very important meaning. have For example, if the load is increased and the gap is narrowed, the followability of the head 3 to the disk 5 will improve and good magnetic recording and reproducing will be possible, but on the other hand, when the disk 5 starts rotating or stops rotating, the levitation force disk 5 because it does not occur sufficiently.
There will be more friction with the As a result, the smooth surfaces 1a, 1
b and the magnetic head 3, resulting in a significant deterioration in their lifespan and operational stability. Furthermore, if the load is lightened to widen the minute gap, good magnetic recording and reproduction cannot be expected. Therefore, it is very difficult to optimally set the above-mentioned load to enable good magnetic recording and reproduction.

In addition, the tapered surfaces 4a and 4b that obtain the above-mentioned levitation force
The taper angle of is very small, usually around (0°20'). Therefore, in this way, the tapered surfaces 4a, 4b
It was very difficult to form the film with high precision, and there was also the problem that the manufacturing yield was low.

In other words, the floating head slider of the conventional structure has problems such as not only being difficult to manufacture, but also requiring highly accurate adjustment when incorporated into a device. It has been difficult to prevent this wear and to always perform stable and good magnetic recording and reproduction.

[Purpose of the invention]

The present invention was made in consideration of these circumstances, and its purpose is to stably set a minute gap between the recording medium and prevent its wear, thereby enabling good magnetic recording and reproduction. To provide an inexpensive and highly practical floating head slider.

[Summary of the invention]

The present invention provides a pressure increase groove and a pressure decrease groove on the smooth surface of a slider body that holds a magnetic head that faces a recording medium, and in particular, the pressure increase groove is provided in a direction in which the pressure increase groove is moved relative to the recording medium. The depth of the groove is set to 1.5 to 5.0 times the floating gap between the smooth surface and the recording medium, and the depressurization groove is formed on the rear side in the relative movement direction. The groove is realized as a groove that widens toward the side, and the depth of the groove is set to be 5 to 20 times the floating gap.

〔Effect of the invention〕

Thus, according to the present invention, the pressure increasing groove and the pressure reducing groove whose groove depths are set as described above generate and balance stable pressure with each other, so that a desired floating gap can be set extremely stably. I can do it. Furthermore, since these grooves can be obtained with high precision using, for example, etching technology, they are easy to manufacture and can be manufactured at low cost. As described above, since the slider main body exhibits stable flying characteristics, it can prevent its wear and provide great practical effects such as enabling good magnetic recording and reproducing by the magnetic head.

[Embodiments of the invention]

Hereinafter, one embodiment of the present invention will be described with reference to the drawings.

FIG. 3 is a perspective view showing a schematic configuration of a floating head slider according to an embodiment, and the same parts as those of the conventional head slider shown in FIG. 1 are designated by the same reference numerals. This floating head slider is characterized by having conventional tapered surfaces 4a, 4 on the smooth surfaces 1a, 1b of the slider body 2 facing the magnetic recording medium 5.
Instead of forming the grooves 11a and 1 for boosting the pressure,
1b, 12a, 12b and pressure reducing grooves 13a, 13b
The point is that The pressure increasing grooves 11a, 11
b is provided on the front side of the smooth surfaces 1a and 1b, and is realized as a groove having a so-called "dog" shape with a tapered shape on the rear side in the direction of relative movement with the magnetic recording medium 5. ing. In addition, the other boosting groove 1
2a and 12b also have a similar shape, and are provided on the rear side of the smooth surfaces 1a and 1b. The pressure reducing grooves 13a and 13b are formed by the smooth surfaces 1a and 13b.
1b, that is, the pressure increasing groove 11a,
A dogleg-shaped groove is provided at an intermediate position between 11b, 12a, and 12b, and widens toward the rear in the relative movement direction. These grooves 11
a, 11b, 12a, 12b, 13a, 13b
are provided, for example, at positions that equally divide the smooth surfaces 1a and 1b into four in the longitudinal direction.

Therefore, each of these grooves 11a, 11b, 12
a, 12b, 13a, 13b are smooth surfaces 1a, 1 using ion etching method or sputter etching method.
The positional accuracy and shape accuracy of the groove patterns formed in the grooves b are extremely high, comparable to the error level of the digital micrometer used to create the original pattern. In addition, the groove depth is determined by the etching speed of 1 to 1 per hour.
It is specified by controlling the etching time under conditions as small as 2 μm, and the desired dimensions are determined within an error range of ±0.1 μm or less.

In this way, the smooth surface 1 of the slider body 2
Pressure increasing grooves 11a, 11b, 12a, 1 in a, 1b
2b and pressure-reducing grooves 13a, 13b are incorporated into a magnetic disk device,
When the recording medium 5 is rotated at high speed while facing the magnetic disk recording medium 5, the pressure of the air flowing between the smooth surfaces 1a and 1b and the recording medium 5 increases as shown in FIGS. 4a and 4b. As a result, the head slider floats above the recording medium 5 while forming a predetermined minute gap. That is, the pressure increasing grooves 11a, 11b, 12a, 1
2b locally compresses the flowing air;
This generates a positive floating force and lifts the slider body 2. At the same time, the pressure reducing groove 13
a, 13b locally expands the flowing air;
Generate negative pressure. This negative pressure is applied to the slider body 2
This has the effect of narrowing the gap between the smooth surfaces 1a, 1b and the recording medium 5.

However, these grooves 11a, 11b, 12a,
The pressure distribution between the recording medium 5 and the smooth surfaces 1a, 1b due to the circulating air generated by the air flow generated by the air flow generated by the air flow generated by the air flow generated by the pressure distributions 12b, 13a, 13b is approximately as shown in FIG. The main body 2 floats while stably forming a predetermined minute gap between its smooth surfaces 1a, 1b and the recording medium 5.

By the way, the pressure increasing grooves 11a, 11b, 12
a, 12b and pressure reducing grooves 13a, 13b each exhibit their functions as follows. That is,
As described above, the pressure increasing grooves 11a, 11b, 12a, and 12b have a tapered shape on the rear side in the relative movement direction. Therefore, the air flowing between the smooth surfaces 1a, 1b and the recording medium 5 from the front side in the relative movement direction flows through the pressure increasing grooves 11a, 11b, 12a,
When it enters 12b, it is gradually compressed due to its drawing shape. This compressed air seeks an escape route on the upper surface of the groove and attempts to return to its original state, and this force causes a floating force (positive pressure) on the slider. On the other hand, since the pressure reducing grooves 13a and 13b have a shape that widens toward the rear side in the relative movement direction, the flowing air that has entered the pressure reducing grooves 13a and 13b is transferred to the pressure increasing grooves 13a and 13b.
Contrary to the case of a, 11b, 12a, and 12b, the expansion process gradually follows. As a result, a negative pressure is generated to reduce the effective cross-sectional area of the groove so that the air returns to its original state. Therefore, the pressure increasing grooves 11a, 11b, 12 that generate pressure in this way
It can be said that the shape of the grooves a, 12b and pressure reducing grooves 13a, 13b plays a very important role.

Note that these grooves 11a, 11b, 12a, 12
It goes without saying that where on the smooth surfaces 1a, 1b the smooth surfaces 1a, 13b, 13a, 13b are provided is also important in obtaining the desired pressure distribution between the smooth surfaces 1a, 1b and the recording medium 5. do not have. At this time, due to the floating force obtained by the pressure increasing grooves 11a, 11b, 12a, 12b, the smooth surfaces 1a, 1b and the recording medium 5
If they become parallel, the recording medium 5 of the slider body 2
The tracking characteristics are improved. This promotes improvement in the recording and reproducing characteristics of the magnetic head 3 and greatly contributes to prevention of crashes. Moreover, the stability of the slider in the pitching direction is also increased. Furthermore, the two parallel smooth surfaces 1a and 1b facing the recording surface have a structure that exhibits extremely stable running stability even in the rolling direction. Therefore, even if these factors are considered comprehensively, a slider that runs in a small gap has extremely good running stability. In addition, as mentioned above, the pressure increasing grooves 11 are provided at two locations on each of the smooth surfaces 1a and 1b.
It can be said that it is desirable to set the distance between a, 11b, 12a, and 12b as long as possible. However, these grooves 11a, 11b, 12a, 12b
If the smooth surfaces 1a, 1b are provided close to the air inflow end and the air outflow end, the smooth surfaces 1a, 1b will come into contact with the recording medium 5 when the recording medium 5 starts or stops rotating. This may cause wear or chipping of the ends, which may change the groove shape. Therefore, it is desirable to set the formation positions of the pressure increasing grooves 11a, 11b, 12a, and 12b in consideration of preventing changes in the pressure generation state due to changes in the groove shape. Therefore, taking this into consideration, each groove 11a, 11b, 12a, 12b, 1
3a and 13b are provided on the smooth surfaces 1a and 1b, respectively, it is possible to ensure stability in the pitching direction of the slider body 2, improve the tracking characteristics for the disk recording medium 5, and perform good recording and reproduction. becomes. From this point of view, it is preferable to provide grooves at positions 0.3 times the total length of the smooth surface from both the front and rear ends of the smooth surface.

By the way, each of the grooves 11a, 11b, 12a,
The groove shapes of 12b, 13a, and 13b correspond to the recording medium 5.
It has a converging shape or a shape that widens toward the rear in the direction of relative movement with respect to the rear side, and is typically realized as a dogleg shape as shown in FIG. 5a. Furthermore, the fifth
It is also possible to realize various shapes as shown in Figures b to e.

However, if the angle θ formed by the groove center of such a dogleg-shaped groove is defined as an included angle, the pressure generated on the smooth surfaces 1a and 1b changes depending on this included angle θ. Figure 6a shows the relationship between the included angle in the pressure increasing groove and the generated pressure f ₍₊₎ , and Figure 7 a shows the relationship between the included angle and the generated pressure f _(-) in the pressure reducing groove. It is. As shown in FIG. 6a, in the case of the pressure increasing groove, the smaller the included angle θ, the greater the floating force, that is, the pressure f ₍₊₎ can be obtained. However, on the other hand, reducing the included angle θ means that the occupied length of the grooves in the longitudinal direction of the smooth surfaces 1a, 1b becomes longer, which places great restrictions on the groove forming positions. Therefore, when adjusting the generated pressure by the included angle θ, it is preferable to set the included angle θ to 10 to 100° as a practical range. On the other hand, in the case of pressure reducing grooves, as shown in Figure 7a, negative pressure f _(-) is generated when the included angle θ is approximately 50° or less, and positive pressure is generated when the included angle is greater than the above angle. It becomes pressure. This is determined by the balance between the negative pressure generated by the air flowing into the groove and the positive pressure generated due to the existence of the groove, and in order to increase the negative pressure, the included angle θ should be adjusted as much as possible. It turns out that it is better to make it smaller. Therefore, when considering the degree of freedom in forming this pressure reducing groove, it is desirable to control the negative pressure by setting the included angle θ to about 10 to 45 degrees.

Further, the pressure generated in the pressure increasing groove and the pressure reducing groove formed by setting the included angle θ in this manner is greatly influenced by the depth of the groove. FIG. 6b shows the relationship between the generated pressure and the groove depth of the pressure increasing groove, and FIG. 7b shows the relationship between the generated pressure and the groove depth of the pressure reducing groove. Note that the groove depth is shown normalized by the floating gap, that is, the minute gap, between the smooth surfaces 1a, 1b and the recording medium 5. As shown in FIG. 6b, the pressure f ₍₊₎ obtained by the pressure increasing groove becomes maximum when the groove depth is set to approximately three times the floating clearance. Therefore, it can be said that if the pressure increasing groove is set to a groove depth that provides this peak value, the pressure generation efficiency will be greatly improved. Further, at this time, even if manufacturing errors in the groove depth are considered, it is preferable to use a position near the peak where the dependence of pressure generation on the groove depth is small. Therefore, considering the inclination of the smooth surfaces 1a and 1b with respect to the recording medium 5, the generated pressure can be obtained practically by setting the groove depth of the pressure boosting groove to about 2 to 10 times the floating gap. In particular, when the gap is made 1.5 to 5.0 times the above-mentioned gap, it becomes possible to obtain a good buoyancy force that can most effectively control the buoyancy gap.
In addition, it is also useful to make use of such properties regarding the groove depth, for example, to set the groove depth to 5 to 20 times the floating gap to keep the floating pressure low. This can be effectively utilized when the floating pressure becomes excessive with respect to the area of the smooth surfaces 1a and 1b, thereby causing a problem of wear. In addition, the upper limit
The reason why the groove depth was set at 20 times was set in this range because it was considered that increasing the groove depth was not a good idea due to various problems such as accuracy and processing time.

On the other hand, the pressure generated by the pressure reducing groove is relatively broad as shown in FIG. 7b, but reaches a peak when the groove depth is approximately six times the floating gap. Therefore, in consideration of the pressure f ₍₊₎ obtained by the pressure increasing groove, if the groove depth of this pressure reducing groove is set to, for example, 5 to 20 times the floating gap, there It becomes possible to stably generate negative pressure f _(-) by efficiently utilizing the inflowing air. Therefore, the depth of the pressure increasing groove is set to 1.5 to 5.0 times the floating gap, and the groove depth of the pressure reducing groove is set to 5 to 5 times the floating gap.
If set to 20 times, it becomes possible to effectively utilize the flowing air to generate pressure and stably obtain the desired floating gap (micro gap). In addition, its dynamic stability can be sufficiently improved. still,
In this case, it is practically desirable to set the groove depth of the pressure reducing groove to be at least twice the groove depth of the pressure increasing groove.

Thus, according to the floating head slider having pressure increasing grooves and pressure reducing grooves on the smooth surface as described above,
The effects of the above-mentioned grooves are synergistic with respect to the rotation of the recording medium 5, and the following effects are obtained. That is, when the recording medium 5 is stationary, the slider moves along its smooth surface 1.
a and 1b are brought into contact with the recording medium, but when the recording medium 5 starts rotating or when the relative speed of the recording medium 5 with respect to the slider is small when trying to stop rotation, the pressure increasing groove mainly performs its function. Demonstrate. As a result, the slider body 2 receives the floating force and floats, forming a predetermined minute gap with the recording medium 5. When the recording medium 5 rotates at a constant high speed and the relative speed increases, the pressure reducing groove will also perform its function in addition to the pressure increasing groove. As a result, the negative pressure of the pressure reducing groove acts to reduce the large floating force generated by the pressure increasing groove, and the smooth surfaces 1a, 1b and the recording medium 5 are separated from each other by the above-mentioned minute gap. It will become stable. In other words, by forming the minute gap, the floating force due to the pressure increasing groove and the negative pressure due to the pressure reducing groove stably collide with each other. Since the floating gap, that is, the minute gap between the recording medium 5 and the recording medium 5 is controlled by the pressure generated by each of these grooves, there is no need to apply a load as in the conventional case, and the airflow is extremely good. Be self-stabilizing.

Furthermore, as described above, since each groove generates pressure to control the attitude of the slider, stability in the pitching direction is excellent, and good magnetic recording and reproduction by the magnetic head is possible. Furthermore, since the slider can be stably floated, wear caused by the recording medium can be significantly reduced. Therefore, it is possible to ensure reliability and perform stable operation over a long period of time.

Further, each of the grooves can be formed easily and with high precision by using the etching technique as described above. Therefore, it is easy to manufacture, and the floating head slider can be manufactured at low cost with good yield, and its practical advantages are enormous.

Note that the present invention is not limited to the above-described embodiments. For example, the formation positions of the pressure increasing grooves and pressure reducing grooves on the smooth surface, their number, shape, groove depth, etc. may be determined in consideration of mutual balance according to the respective specifications. In short, the present invention can be implemented with various modifications without departing from the gist thereof.

[Brief explanation of drawings]

Figure 1 shows a conventional floating head slider;
2a and 2b are diagrams showing the attitude of the head shown in FIG. 1 and the pressure distribution forming the floating gap, FIG. 3 is a diagram showing a floating head slider according to an embodiment of the present invention, and FIG. a and b are diagrams showing the attitude of the slider of the embodiment and the distribution of pressure forming the floating gap, FIGS.
e is a diagram showing the groove shapes of the pressure increasing groove and the pressure reducing groove;
6A and 6B are diagrams showing the characteristics of the pressure increasing groove, and FIGS. 7A and 7B are diagrams showing the characteristics of the pressure reducing groove. 1a, 1b...smooth surface, 2...slider body, 3
...Magnetic head, 5...Recording medium, 11a, 11
b, 12a, 12b...pressure boosting groove, 13a, 13
b...Groove for pressure reduction.

Claims (1)

[Claims] 1. A slider body that holds a magnetic head facing a recording medium and has a smooth surface facing the recording medium, and a pressure increasing groove and a pressure decreasing groove provided on the smooth surface of the slider body. The boosting groove has a profile opening at a predetermined angle from the magnetic head side, and the groove depth is set to be 1.5 to 5.0 times the floating gap between the smooth surface and the recording medium. Floating device, wherein the depressurizing groove has a contour shape opposite to that of the pressurizing groove, and the groove depth is set to be 5 to 20 times as large as the floating gap. head slider.