JPS62189685A - Negative pressure floating head slider - Google Patents

Abstract

PURPOSE:To attain the extremely stable floating characteristics by providing a recessed groove part containing its closed circumference to a positive pressure generating surface. CONSTITUTION:A recessed groove 4a is formed on a positive pressure generating surface 2a. Thus the pressure is approximately equal to or less than the atmospheric pressure at the part of the groove 4a. While the area between the termination of the groove 4a and the trailing edge part of a slider serve as a positive step bearing and therefore the wedge effect is improved more. As a result, the reduction of the positive load capacity is minimized even though a lubricant fluid flows into the slider with a yawing angle. That is, the wedge effect of the slider is increased owing to the groove 4a formed on a pair of positive pressure generating surfaces. This suppresses greatly the positive pressure drop caused by the yawing angle and reduces greatly the reduction of the floating amount due to the yawing angle.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a negative pressure floating head slider, and more particularly to a negative pressure floating head slider that flies stably in an ultra-small gap used in a rigid magnetic disk device. It is.

(Prior art) As the capacity of the floating head slider (hereinafter simply referred to as slider) for magnetic disk devices increases, the amount of floating head is becoming smaller and smaller, and currently the level is several times the mean free path of air molecules. It has been miniaturized to. As is well known, the sliders that have been put into practical use so far are twin-barrel positive pressure sliders that have a Cheeverd flat type dynamic pressure gas bearing surface that has a light load and good dynamic followability. However, since the air film rigidity of this positive pressure slider is approximately proportional to the pressing force, there is a certain limit to increasing the rigidity of the slider adopting the contact start/stop method. This is because increasing the pressing force to reduce the floating amount of the slider increases the surface pressure of the slider, which causes wear when sliding in contact with the recording medium. In order to overcome these problems, we have recently developed a next-generation slider, the Negative Pressure Floating Head Slider (hereinafter referred to as "Negative Pressure Floating Head Slider"), which uses photolithography technology to create a minute reverse step surface within the air film lubricated surface of the slider to generate negative pressure. (simply referred to as negative pressure slider) are being actively researched. According to the negative pressure slider, a negative pressure is generated instead of increasing the pressing force, so a slider with a light load and a small floating amount can be obtained. FIGS. 3(a) and 3(b) are front views showing an example of a conventionally proposed negative pressure slider, respectively;
FIG.

In the figure, IC is a tapered surface that spans the entire width of the slider, 2C is a positive pressure generation surface, 3C is a reverse step surface that generates negative pressure, and 5C is a cross rail surface that is on the same plane as the positive pressure generation surface. be. Since this negative pressure slider has a tapered part over the entire width of the slider, the pressure rise due to air film lubrication at the tapered part is remarkable, as shown in Figure 4 (a).
) and (b), the lifting characteristics of the recording medium at low circumferential speeds are better than those of the other conventional examples shown in (b).

(Problems to be Solved by the Invention) On the other hand, recently there has been an active development of small-sized large-capacity magnetic disk devices for use as files in OA equipment. For example, a small diameter recording medium such as 3.5 inches or 5 inches is used. In such an apparatus configuration, since the running speed of the recording medium cannot be high, a negative pressure slider that quickly transitions from the boundary lubrication area to the fluid lubrication area in the low circumferential speed area is effective. On the other hand, however, rotary actuators are often employed in such small magnetic disk drives in order to improve the reliability of the mechanism and reduce costs. In the case of the rotary actuator, since the magnetic head is given an azimuth angle, the floating head slider has a so-called yaw angle (declination angle), and lubricating gas flows into the slider as an oblique flow. . Therefore, from the viewpoint of electromagnetic conversion characteristics, even when a negative pressure slider is employed, it is necessary to ensure that its floating amount does not exist at the yaw angle. However, the negative pressure slider shown in FIG. 3 has a drawback in that the amount of levitation decreases significantly with respect to this yaw angle.

In other words, as the yaw angle increases, the positive load capacity generated by the negative pressure slider decreases significantly, and at the same time, the negative load capacity, that is, the suction force, increases slightly. Therefore, if a negative pressure slider is installed as a magnetic head in a magnetic disk device that uses a rotary actuator, there will be major problems with its mechanical reliability and electromagnetic conversion characteristics. Become.

The present invention was made in order to eliminate the disadvantages of the negative pressure slider described above, and its purpose is to provide a negative pressure slider that reduces fluctuations in the amount of flying even if the yaw angle changes on the recording medium. It's about doing.

(Means for Solving the Problems) According to the present invention, there is provided a tapered part surface that extends over the entire width of the slider, a pair of positive pressure generating surfaces, and a cross rail surface that is on the same plane as the positive pressure generating surface. and a negative pressure floating head slider having a reverse step surface surrounded on three sides by the positive pressure generating surface and the cross rail surface in the air outflow portion, a recess groove portion having a closed periphery on the positive pressure generating surface. A negative pressure floating head slider is obtained.

(Example) The present invention will be described in detail below using the drawings. 1st
Figures (a) and (b) are a plan view and a side view, respectively, showing an embodiment of the negative pressure slider of the present invention. This embodiment has a tapered surface 1a, a positive pressure generating surface 2a, and
Reverse step surface 3a, cross rail surface 5a and 1
It is composed of a rectangular recess groove 4a provided in the flat portion of the pair of positive pressure generating surfaces 2a.

As is well known, the negative pressure slider has good lifting characteristics with respect to the running speed of the recording medium, so it is suitable for small magnetic disk drives in terms of contact start/stop characteristics. However, it is necessary to investigate whether good levitation characteristics are also exhibited for small magnetic disk drives using rotary actuators. In other words, this term means clarifying the variation in the amount of lift due to the yaw angle of the negative pressure slider.

Therefore, the influence of the yaw angle on the levitation characteristics of the negative pressure slider shown in FIG. 3 was investigated. The investigation method was carried out by numerically solving the modified Reynolds equation, which governs the levitation characteristics of a floating head slider operating at a levitation amount in the submicron range, using techniques such as the finite element method. FIG. 5 is a diagram showing the result of the calculation, which shows the decrease in the floating amount of the positive pressure slider and the negative pressure slider depending on the yaw angle. In the figure, the vertical axis indicates the minimum levitation amount reduction rate (ratio of the minimum levitation amount hmΦ when the yaw angle is set to the minimum levitation amount hmo when the yaw angle is 0°). From the figure, it can be seen that in the case of a negative pressure slider, the decrease in the minimum flying amount due to the yaw angle is greater than that of the Winchester-type positive pressure slider that has already been put into practical use. In other words, this shows that the negative pressure slider has a larger variation in the amount of lift due to the yaw angle. Physically, the reason why the negative pressure slider greatly decreases in flying height is due to two effects: the positive load capacity is significantly reduced, and the negative load capacity is slightly increased due to the yaw angle. However, the main factor is the significant reduction in positive load capacity. FIG. 6 shows the change in positive pressure distribution on the slider center axis depending on the yaw angle of a conventional negative pressure slider. It can be seen that as the yaw angle Φ increases, the positive dynamic pressure generated from the middle part of the slider to the trailing edge part drops significantly. This is because the yaw angle effectively reduces the wedge effect of the slider trailing edge.

This embodiment is characterized by a recess groove 4a on the positive pressure generating surface 2a.
Because of this, the pressure in the recess groove is approximately equal to or lower than atmospheric pressure. Further, since a positive step bearing is formed from the end of the recess groove to the trailing edge of the slider, the wedge effect is greater than in the conventional example. Therefore, even if the lubricating fluid flows into the slider with a yaw angle, the positive load capacity decrease will be extremely small. FIG. 7 shows changes in the positive pressure distribution on the central axis of the slider positive pressure generating surface depending on the yaw angle in the case of the slider of this embodiment.

The figure shows that as the yaw angle Φ increases, the dynamic pressure at the trailing edge slightly decreases, but the dynamic pressure at the middle of the slider is almost independent of the yaw angle and is significantly improved compared to the conventional slider. I understand that.

Furthermore, in the slider of this embodiment, as is clear from the positive pressure distribution in FIG. 7, an extremely large pressure increase is observed at the slider taper portion and the slider trailing edge portion. Therefore, the slider is supported at four points, which has the effect of floating above the recording medium surface more stably than in the conventional example.

FIGS. 2(a) and 2(b) are a plan view and a side view showing another embodiment of the negative pressure slider of the present invention. This embodiment has a tapered surface 1b, a positive pressure generating surface 2b, and a reverse step surface 3b.
.

In addition to the cross rail 5b, a trapezoidal recess groove 4b which is not sandwiched between the pair of positive pressure generating surfaces 2b is formed in the flat surface of the pair of positive pressure generating surfaces 2b. In this case, since the recess groove 4b is not pinched as it approaches the trailing edge of the slider, compared to the first embodiment, the width of the positive pressure generation i2b is isometrically smaller than the trailing edge of the slider. This means that it is wider at the edge. Therefore, it can be seen that even when the lubricating gas flows into the slider at a yaw angle, the pressure generated on the positive pressure generating surface decreases less at the trailing edge than in the first embodiment. In this embodiment, the amount of slider floating due to the yaw angle is smaller than in the first embodiment.

Note that any modification may be made without departing from the spirit of the present invention; for example, the topography of the recess groove and the shape and width of the positive pressure generating surface may be optimized in each case; It goes without saying that the examples do not limit the scope of the invention in any way.

(Effects of the Invention) As explained in detail above, the negative pressure slider of the present invention has the following features:
The wedge effect of the slider is increased by the recess grooves provided on the pair of positive pressure generating surfaces, and the drop in positive pressure due to the yaw angle is greatly alleviated, thereby greatly suppressing the decrease in the amount of flying due to the yaw angle. In addition, since it is a mechanism that supports the prong rider at four points,
Another effect is that extremely stable levitation characteristics can be obtained even in a steady state.

[Brief explanation of drawings]

Figures 1 (a) and (b) and Figures 2 (a) and (b) respectively show a front view, a side view, and Figure 3 (a) and ( b), Figure 4(a),
(b) is a front view and a side view respectively showing an example of a conventional negative pressure slider, FIG.
This figure is a diagram showing the change in the generated positive pressure distribution depending on the yaw angle in a conventional negative pressure slider, and FIG. 7 is a diagram showing the change in the generated positive pressure distribution depending on the yaw angle in the negative pressure slider of the present invention. In the figure, la, lb, lc: tapered part surfaces 2a, 2b, 2c: positive pressure generating surfaces 3a, 3b, 3c: reverse step surface 4a,
4b: Recess groove provided on the positive pressure generating surface Fig. 1 Fig. 2 b Fig. 3 Fig. 4 Fig. 5 Yaw angle (LIX - P-p/pa

Claims (1)

[Claims] A tapered part surface that exists over the entire slider width, a pair of positive pressure generating surfaces, a cross rail surface that is on the same plane as the positive pressure generating surface, and the positive pressure generating surface and the cross rail surface in the air outflow section. In a negative pressure floating head slider having a reverse step surface surrounded on three sides by
A negative pressure floating head slider, characterized in that the positive pressure generating surface is provided with a recess groove portion whose periphery is closed.