JPH05203543A - Apparatus for detecting interaction force in magnetic disk apparatus - Google Patents

Abstract

PURPOSE:To evaluate the interaction force, which acts between the surface of a magnetic disk and the surface of a floating head slider in a magnetic disk apparatus and the change in this interaction force and to achieve the compact configuration for a measuring part for evaluating the interaction force. CONSTITUTION:An ultrasonic oscillating piece 3 and an ultrasonic receiving pieces 4 are attached to a floating head slider 5 and a magnetic disk 6, respectively. The amount of the ultrasonic wave propagation between the floating head slider 5 and the magnetic disk 6 is measured. Interaction force is evaluated based on the amount of the ultrasonic wave propagation, and the time change of the interaction force is obtained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an interaction force detecting device for detecting and evaluating an interaction force acting between a magnetic disk surface and a floating head slider surface in a magnetic disk device.

[0002]

2. Description of the Related Art Generally, a magnetic disk device is composed of at least a rotatable magnetic disk which is a recording medium and a floating head slider which is provided so as to face the surface of the magnetic disk. A magnetic head is provided for reading and writing information on the magnetic disk. When the magnetic disk device is in the rest state, that is, when the magnetic disk is stationary, the magnetic disk and the floating head slider are in contact with each other. Then, when the magnetic disk device enters the operating state, the magnetic disk starts rotating, and the floating head slider floats above the surface of the magnetic disk due to the dynamic pressure effect of the air flow generated thereby.

Here, the magnetic disk surface refers to the surface of the magnetic disk that faces the floating head slider, and the floating head slider surface refers to the surface of the floating head slider that faces the magnetic disk. The interaction force acting between the floating head slider surface and the magnetic disk surface is the attraction force generated between these contacting surfaces, or the frictional force at which these surfaces start relative movement in the sliding direction. It means static friction force.

Since the floating head slider surface and the magnetic disk surface are in contact with each other while the magnetic disk device is at rest and are stationary, depending on the conditions such as temperature and humidity in the magnetic disk device, both surfaces may be in contact with each other. Water molecules intrude between them, causing condensation in the vicinity of the microscopic contact points on both sides. As a result, the interaction force acting on both sides changes. When this interaction force becomes particularly large, that is, when both sides are strongly attracted, the magnetic disk cannot rotate. Therefore, it is very important in designing the magnetic disk device to understand the interaction force acting between the two surfaces in accordance with the change in temperature and humidity.

When the interaction force acting between the floating head slider surface and the magnetic disk surface is measured, for example, when the attraction force is measured, the force required to separate the two surfaces is measured, and when the friction force is measured, both surfaces are measured. The force at which the onset of slipping must be measured. The measurement of these changes in the interaction force needs to be performed over a long period of time, such as several days. Further, the measurement of these interaction forces is often carried out in a constant temperature and constant humidity chamber in order to clarify the conditions of temperature and humidity.

[0006]

In the conventional method for evaluating the interaction force between the floating head slider surface and the magnetic disk surface, the measurement is performed by actually separating or sliding both surfaces in contact with each other. In order to destroy the contact state on both sides for each measurement, 1
If the measurement is performed once, it is necessary to reproduce the contact state on both sides again for the next measurement and wait for a new time from 0. The longer the change is tracked, the longer the measurement becomes. There is a problem that it takes a lot of time.

Further, since the measurement of these interaction forces is generally performed in a constant temperature and humidity chamber, it is necessary to reduce the size of the measuring section. It is necessary to incorporate a fine movement mechanism, a force measurement mechanism, a force sensor, etc. to move the disk relative to each other precisely, and the measurement section becomes large, making it difficult to store it in a constant temperature and humidity chamber. is there.

An object of the present invention is to detect an interaction force acting between a floating head slider surface and a magnetic disk surface and a change in the interaction force can be quickly evaluated and a measuring unit can be downsized. To provide a device.

[0009]

An interaction force detecting device according to a first aspect of the present invention is an ultrasonic oscillator attached to either one of a magnetic disk and a floating head slider, and a magnetic disk and a floating head slider. An ultrasonic receiver that is attached to the one to which the ultrasonic oscillator is not attached, an ultrasonic oscillator that drives the ultrasonic oscillator, and an ultrasonic device that measures the amount of ultrasonic waves input to the ultrasonic receiver. And a sound wave receiver.

The interaction force detecting device of the second invention is an ultrasonic oscillator for applying an ultrasonic current to the ultrasonic wave receiver attached to the magnetic disk and the winding portion of the magnetic head attached to the floating head slider. And an ultrasonic receiver for measuring the amount of ultrasonic waves input to the ultrasonic receiver.

[0011]

When water molecules enter the contact surface between the magnetic disk and the floating head slider or dew condensation occurs, the amount of ultrasonic wave propagation between the magnetic disk and the floating head slider changes. Here, if ultrasonic waves are generated by either the magnetic disk or the floating head slider and the ultrasonic waves are received by the other, the amount of this ultrasonic wave propagation can be measured, and the amount of propagation between the magnetic disk surface and the floating head slider surface can be measured. It is possible to estimate changes in the interaction force due to water molecule intrusion and condensation. In this case, since the measurement is performed without breaking the contact state on both surfaces, it is possible to continuously track the change in the interaction force. Further, since the ultrasonic oscillator and the ultrasonic receiver have a size of several cm square or less, it is possible to significantly reduce the size and weight of the measuring unit.

As a method of generating ultrasonic waves, there is a method of mounting an ultrasonic oscillator on either the magnetic disk or the floating head slider. Further, since a magnetic head is attached to the floating head slider, it may be used that ultrasonic vibration is generated by a so-called magnetostriction effect by applying an ultrasonic current to the winding portion of this magnetic head. ..

[0013]

Embodiments of the present invention will now be described with reference to the drawings. FIG. 1 is a schematic cross-sectional view showing the configuration of an interaction force detection device in a magnetic disk device according to an embodiment of the present invention.

The magnetic disk device to be measured has a floating head slider 5 and a magnetic disk 6. The ultrasonic receiver 3 is attached to the surface of the magnetic disk 6 that is not opposed to the floating head slider 5. The ultrasonic oscillator 2 is attached to the floating head slider 5, and the ultrasonic oscillator 2 is driven by the ultrasonic oscillator 1. On the other hand, the ultrasonic receiver 3 is an ultrasonic receiver 4 that measures the amount of ultrasonic waves input to the ultrasonic receiver 3.
It is connected to the.

Next, the operation of this embodiment will be described.

First, the ultrasonic oscillator 2 is driven by the ultrasonic oscillator 1. Then, the ultrasonic wave from the ultrasonic oscillator 2 is transmitted to the floating head slider 5, passes through the contact surface between the floating head slider 5 and the magnetic disk 6, and then reaches the ultrasonic receiver 3 attached to the magnetic disk 6. Propagate to.
The ultrasonic wave reception signal detected by the ultrasonic wave receiver 3 is amplified by the ultrasonic wave receiver 4, and as a result, the amount of ultrasonic wave propagation between the floating head slider 5 and the magnetic disk 6 is obtained.

Here, the relationship between the interaction force between the magnetic disk surface and the floating head slider surface and the amount of ultrasonic wave propagation between both surfaces will be described with reference to FIG.

Generally, the surface of the magnetic head is rougher than the surface of the floating head slider. This is to prevent moisture from entering the contact portions on both sides and strongly adhering to each other on both sides as much as possible. Therefore, the magnetic disk 6 and the floating head slider 5 are in contact with each other at the protrusion on the magnetic disk 6 side. Then, the propagation of ultrasonic waves between the floating head slider 5 and the magnetic disk 6 is mainly performed at this contact point. It should be noted that if the surface roughness of the magnetic disk 6 is increased, the signal-to-noise ratio (S / N ratio) of the signal to be recorded is lowered, and therefore the surface roughness cannot be extremely increased.

Now, let us consider the case where water molecules penetrate between both surfaces. When water molecules enter, water 7 adheres to the vicinity of the contact point between the floating head slider 5 and the magnetic disk 6. When the moisture 7 adheres in this way, the interaction force between the magnetic disk surface and the floating head slider surface also increases, but the propagation of ultrasonic waves between the floating head slider 5 and the magnetic disk 6 also depends on the adhered moisture 7. It will be done. Eventually, the cross-sectional area of the portion where the ultrasonic wave propagates on the contact surface of both surfaces effectively increases, and the amount of ultrasonic wave propagation increases. Therefore, by tracking the time change of the amount of ultrasonic wave propagation with the ultrasonic receiver 4, it is possible to know the change in the interaction force between the two surfaces, and it is possible to evaluate the interaction force. . In this case, since it is not necessary to separate the floating head slider 5 and the magnetic head 6 for each measurement, it is possible to continuously change the interaction force in real time without destroying the contact state of both surfaces. Can be tracked to.

Next, another embodiment of the present invention will be described with reference to FIG.
Will be explained. Although ultrasonic waves are generated using the ultrasonic oscillator in the above-described embodiment, this embodiment attempts to generate ultrasonic waves using the magnetic head 8 provided in the floating head slider 5. It is a thing.

The magnetic head 8 provided on the floating head slide 5 generally comprises a magnetic core 8a and a winding portion 8b provided around the magnetic core 8a. Therefore, the winding portion 8b is connected to the ultrasonic oscillator 1, the ultrasonic wave receiver 3 is attached to the magnetic disk 6, and the ultrasonic wave receiving unit 3 amplifies the signal detected by the ultrasonic wave receiver 3 to measure the amount of ultrasonic waves. A container 4 is provided.

When the winding portion 8b is driven by an ultrasonic current by the ultrasonic oscillator 1, the magnetic head 8 changes its magnetization in response to the ultrasonic current, and the so-called magnetostriction effect of the magnetic core 8a causes the ultrasonic current to flow. The ultrasonic vibration corresponding to is generated. This ultrasonic vibration propagates to the ultrasonic receiver 3 through the contact surface between the floating head slider 5 and the magnetic disk 6, as in the above-described embodiment. The ultrasonic wave signal propagated to the ultrasonic wave receiver 3 is amplified by the ultrasonic wave receiver 4 and the amount of ultrasonic wave propagation is obtained, whereby the interaction force is evaluated and the time variation of the interaction force is calculated as in the above-described embodiment. Tracking is possible.

The embodiment of the present invention has been described above.
When both an ultrasonic oscillator and an ultrasonic receiver are used, it is clear that the same measurement can be performed by disposing the ultrasonic receiver on the floating head slider side and the ultrasonic oscillator on the magnetic disk side. Is.

[0024]

As described above, the present invention evaluates the interaction force between the floating head slider surface and the magnetic disk surface by determining the amount of ultrasonic wave propagation between the floating head slider and the magnetic disk. As a result, the interaction force can be measured nondestructively, and the measurement time can be greatly shortened when examining the time change of the interaction force as compared with the conventional one. In addition, since the ultrasonic oscillator and the ultrasonic receiver are small and lightweight, there is an effect that the measurement can be performed in a small constant temperature and humidity chamber.

[Brief description of drawings]

FIG. 1 is a schematic cross-sectional view showing the configuration of an interaction force detection device in a magnetic disk device according to an embodiment of the present invention.

FIG. 2 is an enlarged view of a contact surface between a floating head slider and a magnetic disk.

FIG. 3 is a schematic cross-sectional view showing the configuration of an interaction force detection device in a magnetic disk device according to another embodiment of the present invention.

[Explanation of symbols]

 1 Ultrasonic Oscillator 2 Ultrasonic Oscillator 3 Ultrasonic Receiver 4 Ultrasonic Receiver 5 Floating Head Slider 6 Magnetic Disk 7 Moisture 8 Magnetic Head 8a Magnetic Core 8b Winding Part

Claims (2)

[Claims] 1. An interaction force detecting device for evaluating an interaction force between a magnetic disk surface and a floating head slider surface in a magnetic disk device comprising at least a magnetic disk and a floating head slider, wherein: An ultrasonic oscillator attached to one of the floating head sliders; an ultrasonic receiver attached to one of the magnetic disk and the floating head slider to which the ultrasonic oscillator is not attached; An interaction force detecting device in a magnetic disk device, comprising: an ultrasonic oscillator that drives an ultrasonic oscillator; and an ultrasonic receiver that measures the amount of ultrasonic waves input to the ultrasonic receiver. 2. An interaction force detecting device for evaluating an interaction force between a magnetic disk surface and a floating head slider surface in a magnetic disk device comprising at least a magnetic disk and a floating head slider, the device being attached to the magnetic disk. An ultrasonic receiver, an ultrasonic oscillator that applies an ultrasonic current to the winding portion of the magnetic head attached to the floating head slider, and an ultrasonic wave that measures the amount of ultrasonic waves input to the ultrasonic receiver. An interaction force detection device in a magnetic disk device, comprising: a receiver.