JPH0594683A - Magnetic head device for magnetic recording and reproducing device - Google Patents

Abstract

PURPOSE:To provide a magnetic head device for a magnetic recording and reproducing device enabling to obtain an excellent contact start stop characteristic (CSS). CONSTITUTION:A slider 11 is composed with a tilted surface 12 and a sliding surface 13. On the tilted surface, striped forms 17 are formed from an air inflow side to an outflow side. Since at least either condition where an apparent contacted area between the magnetic disk and the slider 11 should be 3-50% or a depth of a groove at a recessed part of the striped forms should be >=50Angstrom , is satisfied, a coefficient of static friction and a coefficient of dynamic friction become small and the excellent CSS characteristic is obtained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic head device of a magnetic recording / reproducing apparatus, and more particularly to a floating magnetic head device suitable for use in a high recording density hard disk device.

[0002]

2. Description of the Related Art In a hard disk device, a magnetic head mounted on a slider is floated on the surface of a magnetic disk through a minute gap to write and read information. When the hard disk device is operated, the magnetic disk rotates at 3000 to 4000 RPM, and an air film is generated between the slider and the magnetic disk. This air film causes buoyancy, and the magnetic head mounted on the slider floats above the magnetic disk. When the magnetic disk is rotated from the stopped state, the magnetic head gradually lifts while rubbing against the magnetic disk. On the contrary, when the magnetic disk is stopped from the rotating state, the magnetic head gradually contacts the magnetic disk from the floating state, and stops on the magnetic disk while rubbing against each other. In this way, the rotation (start) and stop (stop) of the magnetic disk while the magnetic head is in contact (contact) is called contact start stop (hereinafter referred to as CSS). Set (stop, rotation, stop) of the magnetic disk as one cycle and 3
It is required to be able to record and reproduce without problems even after 50,000 cycles have been completed.

6A and 6B are views showing a conventional slider in a magnetic head device of a magnetic recording / reproducing apparatus. FIG. 6A is a plan view of the bottom surface of the slider 1, and FIG. 6B is a side view thereof.
As shown in FIG. 6A, the slider 1 has two inclined surfaces 2 for air inflow and two sliding surfaces 3 respectively. And
In order to obtain the above-mentioned good CSS characteristics, as shown in FIG. 6B, the sliding surface 3, which is the bottom surface of the slider 1, is rounded from the inflow side of the air to the outflow side, that is, a so-called crown. It has a shape.

[0004]

However, recently, in the hard disk device mounted on the book type computer, the magnetic disk is frequently rotated and stopped due to the need for low power consumption. Came. Along with this, the number of times of CSS has increased, and the magnetic disk has also become high recording density, so that better CSS characteristics than ever before are required. therefore,
It is an object of the present invention to provide a magnetic head device of a magnetic recording / reproducing device that can obtain good CSS characteristics.

[0005]

In order to solve the above-mentioned problems of the prior art, the present invention floats a magnetic head mounted on a slider on the surface of a magnetic disk through a minute gap to write and read information. In the magnetic head device of the magnetic recording / reproducing apparatus for performing the above, stripe-shaped unevenness is formed on the sliding surface of the slider that comes into contact with the magnetic disk from the inflow side of the air to the outflow side thereof, Apparent contact area with 3 to 50
% And at least one of the second conditions in which the groove depth of the stripe-shaped irregularities is 50 angstroms or more, the magnetic head device of the magnetic recording / reproducing apparatus is provided. Is.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A magnetic head device of a magnetic recording / reproducing apparatus of the present invention will be described below with reference to the accompanying drawings. 1 is a side view showing an embodiment of the magnetic head device of the present invention, and FIG.
Is a plan view of the bottom surface of a slider which is the magnetic head device of the present invention, FIG. 3 is a partially enlarged sectional view of the slider which is the magnetic head device of the present invention, and FIGS. 4 and 5 are for explaining the magnetic head device of the present invention. FIG.

First, considering the causes of deterioration of CSS characteristics, the following (a) to (c) can be given. (A) Dust generated by the contact between the slider and the magnetic disk adheres to the sliding surface together with the lubricant contained in the magnetic disk and causes frictional heat to burn the magnetic head, thereby causing a head crash. (B) The above dust is sandwiched between the magnetic disk and the magnetic head to increase the friction coefficient. The reason why the friction coefficient becomes high is considered to be that the dust rolls. (C) Since the atmospheric pressure at the tip of the magnetic head changes abruptly, abnormal water (water contained in the air) is generated and adheres to the tip of the magnetic head, causing head crashes and magnetic disks. Generates attraction with the magnetic head.

Further, the following conditions (a) to (c) can be considered as conditions for obtaining good CSS characteristics. (A) The surface roughness (surface irregularities) of the slider is large. (A) The contact area between the slider and the magnetic disk is small. (C) Small friction due to dust etc.

Taking these various conditions into consideration, various experiments were conducted, and good CSS characteristics were obtained by forming the slider surface (bottom surface) into a stripe shape having a plurality of grooves from the air inflow side to the output side. Do you get it. Hereinafter, the configuration and characteristics of the magnetic head device of the present invention will be described in detail. As shown in FIG. 1, a slider 11 according to the present invention.
Is attached to the suspension 14. A winding 15 is wound around the magnetic head 18 mounted on the slider 11. The bottom surface of the slider 11 is composed of an inclined surface 12 for inflowing air and a sliding surface 13 that repeats contact sliding / floating with the magnetic disk 16.

As shown in FIG. 2A, the slider 11 has two inclined surfaces 12 and two sliding surfaces 13, and the sliding surface 13 faces the running direction of the magnetic disk 16. That is, that is, stripe-shaped irregularities 17 (hereinafter, referred to as stripe shapes 17) having a certain width are formed from the air inflow side to the air output side. FIG. 2B is an enlarged view of the sliding surface 13 shown in FIG.
Is a convex portion, and 17b is a concave portion. The top surface of the convex portion 17 a contacts the magnetic disk 16. Furthermore, FIG.
It is an A1-A2 expanded sectional view of (B). The groove depth of the concave portion 17b of the stripe shape 17 is L.

FIG. 4 shows changes in the static friction coefficient (μs) and the dynamic friction coefficient (μk) depending on the apparent contact area of the slider 11 and the groove depth L according to the magnetic head device of the present invention. The apparent contact area of the slider 11 is the apparent contact area (%) = the area of the top surface of the convex portion of the stripe shape 17 (total contact area) / the area of the sliding surface 13. When the stripe shape 17 is not formed and the entire sliding surface 13 contacts the magnetic disk 16, the apparent contact area is 100%. The coefficient of static friction means the coefficient of friction just before the slider 11 in contact with the magnetic disk 16 tries to move. The coefficient of dynamic friction means the coefficient of friction of the slider 11.
Is the coefficient of friction when the sliding contact with the magnetic disk 16 occurs. These friction coefficients are calculated from the torque characteristics of the motor that rotates the magnetic disk 16.

First, from the relationship between the apparent contact area and the coefficient of static friction shown in FIG. 4A, the apparent contact area is 50%.
It can be seen that the static friction coefficient sharply increases when the value exceeds.
From the relationship between the groove depth L and the coefficient of static friction shown in FIG.
It can be seen that when the groove depth L exceeds 50 Å, the static friction coefficient stabilizes at a small value. FIG. 4 (C) shows the relationship between the number of CSS times and the coefficient of dynamic friction when the groove depth L is set to 50 angstroms or more.
It is measured for 70%. When the apparent contact area is 3% to 50%, the coefficient of dynamic friction is small even after 30,000 CSS times, whereas when it exceeds 50%, the CSS number becomes 5
It can be seen that the coefficient of dynamic friction rapidly increases from around 1,000 times. In addition, FIG. 4D shows the relationship between the number of CSS times and the coefficient of dynamic friction when the apparent contact area is 3% and the groove depth L is 5
It is measured at 0 angstrom or more and less. It can be seen that the coefficient of dynamic friction is small when the groove depth L is 50 angstroms or more, whereas the coefficient of dynamic friction is considerably large when the groove depth L is less than 50 angstroms.

Further, FIG. 5A shows the relationship between the number of CSSs and the coefficient of dynamic friction when the groove depth L is less than 50 angstroms, and FIG. 5B shows the relationship between the apparent contact area and 3%. The relationship between the number of CSSs and the coefficient of dynamic friction is shown. As can be seen from FIG. 5A, even if the groove depth L is less than 50 Å, the apparent contact area is 3 to 50%.
In that case, considerably good CSS characteristics can be obtained as compared with the conventional case in which the groove (unevenness 17) is not formed. In addition, FIG.
As can be seen, even if the apparent contact area is 70%, if the groove depth L is 50 angstroms, a considerably good CSS characteristic can be obtained. In addition, FIG.
In (D) and FIG. 5, the broken line is the upper limit of the kinetic friction coefficient tentatively specified by the Company.

From these experimental results, it was found that good CSS characteristics can be obtained by making the slider 11 as follows. (A) Stripe-shaped unevenness (striped shape 1) from the air inflow side to the output side of the sliding surface 13 of the slider 11
7) is formed. (A) The apparent contact area of the slider 11 is set to 3 to 50%. (C) The groove depth L of the recess of the sliding surface 13 is set to 50 angstroms or more. By adding either condition (a) or (c) to condition (a), CSS that is considerably better than the conventional one
The characteristics can be obtained, and by adding both the conditions (a) and (c) to the condition (a), a better CSS property can be obtained.

It was also confirmed that the following relational expression holds between the apparent contact area and the groove depth L and the coefficient of static friction. Relational expression between apparent contact area x and coefficient of static friction (μs): μs = ax ⁴ + bx ³ + cx ² + dx + e where a = −4.63 × 10 ⁻⁸ , b = 8.87 × 10
^-6 , c = -4.31 × 10 ^-4 , d = 8.09 × 10 ^-3 ,
e = 1.58. Relational expression between groove depth L and static friction coefficient μs: μs = aL ⁴ + bL ³ + cL ² + dL + e where a = 3.33 × 10 ⁻⁸ and b = −9.29 × 10
^-6 , c = 9.71 × 10 ^-4 , d = -4.54 × 10 ^-2 ,
e = 9.97. Note that these relational expressions are calculated from the measured values using the least squares method.

The lower limit of the apparent contact area is 3%.
Is the minimum value at which the stripe shape 17 is formed on the slider 11, the apparent contact area is measured, and the above experiment can be performed. In addition, the concave portion 17 of the stripe shape 17
It is considered that b serves to discharge dust and the like sandwiched between the magnetic disk 16 and the convex portion 17a and reduce rolling friction. Although the magnetic head device of the hard disk device has been described in the present embodiment, the present invention can be applied to the magnetic head device of the floppy disk device and the magnetic head device for a video tape recorder.

[0017]

As described in detail above, in the magnetic head device of the magnetic recording / reproducing apparatus for writing and reading information, the magnetic head mounted on the slider is floated on the surface of the magnetic disk through a minute gap. The slider has a sliding surface that comes in contact with and slides on the magnetic disk. Stripe-shaped irregularities are formed from the air inflow side to the air outflow side to make the apparent contact area between the magnetic disk and the slider 3 to 50%. By adding any one of the conditions, or the second condition that the groove depth of the stripe-shaped unevenness is 50 angstroms or more, a considerably better CSS characteristic is obtained as compared with the conventional one. If it is configured so as to satisfy both the second conditions, there is a practically excellent effect that a better CSS characteristic can be obtained.

[Brief description of drawings]

FIG. 1 is a side view showing an embodiment of the present invention.

FIG. 2 is a plan view of the bottom surface of the slider of the present invention.

FIG. 3 is a partially enlarged sectional view of the slider of the present invention.

FIG. 4 is a characteristic diagram for explaining the present invention.

FIG. 5 is a characteristic diagram for explaining the present invention.

FIG. 6 is a diagram showing a conventional example.

[Explanation of symbols]

 11 Slider 12 Gradient Surface 13 Sliding Surface 16 Magnetic Disk 17 Stripe Shape (Striped Concavo-convex)

Claims (1)

[Claims] 1. A magnetic head device of a magnetic recording / reproducing apparatus for writing and reading information by floating a magnetic head mounted on a slider on a surface of a magnetic disk through a minute gap, and contacting the magnetic disk of the slider. A first condition in which stripe-shaped irregularities are formed on the sliding surface from the inflow side to the outflow side of the air, and the apparent contact area between the magnetic disk and the slider is 3 to 50%; A magnetic head device for a magnetic recording / reproducing device, characterized in that at least one of the second conditions for setting the groove depth of the stripe-shaped irregularities to 50 angstroms or more is satisfied.