JPH01214735A - Evaluating method of contact resistance - Google Patents

Abstract

PURPOSE:To enable the selection of combination of a head having a high contact resistance with a magnetic disk, by a method wherein, after the magnetic disk is rotated, a spherical slider is vibrated vertically and the disk and the spherical slider are brought into contact with each other periodically. CONSTITUTION:A spherical slider 4, which is fitted to the fore end of a vibrating rod 7 through the intermediary of a gimbal support spring 5, is so constructed that it is vibrated forcedly in the vertical direction by vibrating the vibrating rod 7 at a prescribed period by a vibrator 6, so that a periodical contact thereof with a magnetic disk 1 may occur. On the occasion when evaluation of a head/the disk is executed, a carriage 9 is moved to position the slider 4 at a prescribed position on the surface of the disk 1, and the disk 1 is rotated normally. Next, at a time point when the disk 1 gets to regular rotation, the slider 4 is vibrated at a prescribed period by the vibrator 6 and thereby the periodical contact with the disk 1 takes place. The fore end of the slider 4 is worn by the contact with the disk 1. The volume of a worn part in various test times is calculated, and the amount of wear of the slider 4 is obtained thereby.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for evaluating head/disk contact strength in a magnetic disk drive, and particularly to a contact strength evaluation method suitable for selecting a head/disk combination with high contact strength.

[Conventional technology]

In order to achieve high-density recording in magnetic disk drives, the flying gap (flying height) between the head and the disk tends to become narrower. Along with this, the probability of contact between the head and the disk increases, increasing the risk of head crash. In view of this situation, there is a need to develop heads and disks that are highly resistant to crushing even when the heads and disks come into contact with each other.

When developing this, it is important to consider that if the wear resistance of the head material is high and the wear resistance of the disk is low, the disk will easily wear out over time and lead to a crash. If the wear resistance of the disk is low and the wear resistance of the disk is high, there is a concern that the head will deteriorate over time and the magnetic recording element will be destroyed. Furthermore, as described above, as the flying type decreases, the probability of continuous contact between the head and the disk increases, and the possibility of a crash is also high.

Therefore, it is meaningless to have high wear resistance for either the head or the disk; both the head and disk have high wear resistance.
It is important to ensure that a particular combination has high wear resistance.

Conventionally, a known method for evaluating the strength of magnetic disks is disclosed in Technical Report Nα86-076 (published on January 20, 1986).
There is a method disclosed in This method evaluates the strength of the magnetic disk by rotating a magnetic disk, using a vibrator to vibrate the actual head in synchronization with the rotation of the magnetic disk, and forcing the head and disk into contact. It is.

[Problem to be solved by the invention]

The above-mentioned conventional technology is effective in that it simulates the contact between the head and the disk when the device is in operation, since the strength is evaluated by bringing the actual head into contact with the disk, but as mentioned above, the wear resistance is It was not sufficient to select a particular head/disk combination that would result in high performance.

The present invention has been made in view of the above circumstances, and its purpose is to solve the above-mentioned problems in the conventional contact strength evaluation method for magnetic disk drives, and to facilitate the selection of head and disk combinations with high contact strength. The object of the present invention is to provide a suitable contact strength evaluation method.

[Means to solve the problem]

The above object of the present invention is to provide a contact strength evaluation mechanism having a magnetic disk medium and a slider placed on the magnetic disk medium, in which the slider is a spherical slider, and
After rotating the magnetic disk medium, the spherical slider is vibrated in the vertical direction using a vibrator to periodically bring the magnetic disk medium and the spherical slider into contact with each other. This is achieved using a contact strength evaluation method.

[Effect]

In the contact strength evaluation method according to the present invention, the head/
By measuring the amount of wear on the spherical slider when the disk contact energy is constant, various characteristics of the head material (
Hardness, thermal conductivity, mass, etc.) can quantitatively determine the degree of damage caused to the head/disk, and by measuring the amount of disk surface wear, the disk surface structure (filler particle size/content, magnetic field orientation method) can be quantitatively determined. , paint mixing method or surface roughness, etc.)
It is possible to quantitatively understand the degree of damage caused to the head/disk.

The amount of wear of the above-mentioned one-spherical rotor and the amount of disk wear are closely related, and the amount of wear is determined by the mutual influence of various characteristics of the head material and the surface structure of the disk.

Although the above example describes the case where the head/disk contact energy is constant, in the contact strength evaluation method according to the present invention, the contact energy is changed by changing the excitation force, excitation period, disk rotation speed, etc. It is also possible to include this in the evaluation.

〔Example〕

Embodiments of the present invention will be described in detail below with reference to the drawings.

FIG. 2 is a side view of the head in a floating state. By rotating the magnetic disk 1, the magnetic head 2 begins to slide on the surface of the magnetic disk 1, and when a certain number of rotations is reached, it wets the surface of the magnetic disk 1 and begins to float. after that,
When the magnetic disk 1 reaches high-speed steady rotation, the force of the airflow generated by the rotation pushing up the head 2 is balanced by the force of the gimbal support mechanism pushing down the head 2, and the head maintains a constant gap while maintaining the magnetic field. It levitates above the disk surface.

Here, when disturbance factors such as disk runout and gimbal vibration are added, contact occurs between the head and the disk.

FIG. 1 is a diagram showing an example of the configuration of an apparatus for implementing the contact strength evaluation method according to the present invention. In the figure, 1 is the magnetic disk, 3 is the rotation direction of the magnetic disk 1,
4 indicates a spherical slider. The spherical slider 4 is attached to the tip of an excitation rod 7 via a gimbal support spring 5, and the spherical slider 4 is attached to the tip of an excitation rod 7 through a gimbal support spring 5. The rotor 4 is configured to forcibly vibrate in the vertical direction to generate periodic contact with the magnetic disk 1. In addition, 9 is a carriage, and as shown by the arrow 10, it is comprised so that it can reciprocate. Further, 11 is a piezoelectric element, the output of which is displayed on an oscilloscope 13 via an amplifier 12.

When evaluating heads/disks using this packaging,
First, the carriage 9 is moved to position the spherical slider 4 at a predetermined position on the surface of the magnetic disk 1. Next, the magnetic disk 1 is rotated normally. During this time, a constant gap is maintained between the spherical slider 4 and the magnetic disk 1. When the magnetic disk 1 reaches a steady rotational speed, the spherical slider 4 is vibrated at a constant period by the vibrator 6 (as shown by the arrow 8) as described above, so that the distance between the magnetic disk 1 and the magnetic disk 1 is increased. generate periodic contact.

Thereafter, test times are determined and contact tests are conducted at various test times.

FIG. 3(a) is an enlarged side view of the spherical surface element 4 before the test, and FIG. 3(b) is an interference fringe diagram as seen from six directions.

Moreover, FIG. 4(a) is an enlarged side view of the spherical surface element 4 after the test, and FIG. 4(b) is an interference fringe diagram seen from six directions. The tip of the spherical slider 4 is worn out due to contact with the disk. The shaded area B in FIG. 4(b) is the worn part, and the volume of the worn part is calculated and used as the amount of wear of the spherical slider 4.

FIG. 5(a) shows the results of measuring the surface of the magnetic disk 1 before the test using a roughness meter, and FIG. 5(b) shows the results of measuring the surface of the magnetic disk 1 before testing.
indicates the shape after the test.

The shaded area C is the worn part, and the volume of the worn part is calculated and used as the amount of wear of the magnetic disk.

FIG. 6 shows an example of the evaluation results obtained by the above-mentioned apparatus, in which the horizontal axis represents the disk wear amount, and the vertical axis represents the slider wear amount. Due to the combination of slider and disk, the slider is hard to wear and the disk is easy to wear (Case ■), conversely, the disk is hard to wear and the slider is easy to wear (Case ■), or There are cases where both wear out proportionally (case ■). Therefore, from this it is possible to select a combination of a head and a disk that are unlikely to wear each other.

According to the above embodiment, by making the slider shape spherical, the contact state with the magnetic disk can always be started from a constant state at the start of the test, and analysis is also facilitated. There is.

In the test apparatus shown in FIG. 1, the gimbal support spring 5 was attached directly to the excitation rod 7 to vibrate the spherical actuator 4, but as shown in FIG. The head arm 14 may be directly vibrated. This method can achieve a vibration pattern that is closer to the actual machine.

〔Effect of the invention〕

As described above, according to the present invention, in a contact strength evaluation mechanism having a magnetic disk medium and a slider located on the magnetic disk medium, the slider is a spherical slider, and the slider is a spherical slider. After rotating the magnetic disk medium, the spherical slider is vibrated in the vertical direction using a vibrator to bring the magnetic disk medium and the spherical slider into periodic contact.

This has the remarkable effect of realizing a contact strength evaluation method suitable for selecting a combination of a head and a disk with high contact strength.

[Brief explanation of the drawing]

Fig. 1 is a diagram showing an example of the configuration of an apparatus for implementing the contact strength evaluation method according to the present invention, Fig. 2 is a side view of the head in a floating state, and Fig. 3 (,) is a spherical slider before testing. (b) is an interference fringe diagram as seen from direction A, and Fig. 4 (
(a) is an enlarged side view of the spherical slider after the test, (b) is an interference fringe diagram seen from six directions, and Figure 5 (a) is the surface of the magnetic disk before the test using a roughness meter. A diagram showing the measurement results,
6(b) is a diagram showing the shape after the test, FIG. 6 is a graph showing an example of the evaluation results, and FIG. 7 is a diagram showing another configuration example of the apparatus for carrying out the contact strength evaluation method according to the present invention. It is a diagram. 1: Magnetic disk, 2: Magnetic head, 4: Spherical slider,
5 Nishinpal support spring, 6: Vibrator, 7: Vibration rod, 9:
Carriage, 14: Herad arm. Patent applicant: Hitachi, Ltd. ie, Patent attorney: Masatoshi Isomura: 1. 1 1' Figure 2 Figure 4 (a) Figure 5 (a) 161. 0 Disc wear amount (μm)

Claims (1)

[Claims] 1. In a contact strength evaluation mechanism having a magnetic disk medium and a slider located on the magnetic disk medium, the slider is a spherical slider, and after rotating the magnetic disk medium, A contact strength evaluation method characterized in that the spherical slider is vibrated in the vertical direction using a vibrator to periodically bring the magnetic disk medium and the spherical slider into contact.