JPS60177479A - Loading system of magnetic head - Google Patents

Abstract

PURPOSE:To prevent friction and absorption by magnetic head's sliding with simple cnstitution, by resonating a slider high as specified from a disk and by loading a magnetic head at a lead-in height. CONSTITUTION:When the number of rotations of a disk medium 1 reaches the specified rotations, a control signal switch is switched; an actuator 2 vibrates in a seek direction (a); a slider 4 resonates, which is isolated at the specified height (ho) from the medium 1 and which is equipped with a gimbal 3 and a magnetic head 44. By this resonance, the head 44 is loaded at the lead-in height where it is isolated at a minute distance from the medium 1, thus eliminating contact and sliding of the head and the disk medium and preventing friction and absorption of the magnetic head and the disk medium with simple constitution.

Description

DETAILED DESCRIPTION OF THE INVENTION (al) Technical Field of the Invention The present invention relates to a method for loading a magnetic head of a magnetic disk device, and particularly to a method for loading a movable magnetic head during use.
This relates to a loading method for a magnetic head that unloads when stopped.

Tbl Prior Art and Problems Currently, the contact start-stop method (C
The mainstream is a method called the 3S method. This literally means a disk-shaped recording medium (hereinafter abbreviated as disk medium).

) when the rotation of the disk is stopped (that is, when information is not being written or read), the magnetic head is kept in close contact with the disk medium, and the disk is rotated along with the writing and reading operations. This is a method in which the magnetic head floats through a gap to write and read information on the disk medium, and when rotation stops, the magnetic head is brought into close contact with the disk medium again.

This method has the advantage of not requiring a particular loading mechanism, but on the other hand, the disk medium and magnetic head slide at a fairly high speed at the start of rotation and just before rotation stops, resulting in wear and tear.

Otherwise, problems such as adsorption are more likely to occur. Therefore, in order to prevent the above-mentioned troubles, it is necessary to require the disk medium and the magnetic head to have wear resistance, and to take measures such as applying lubricating oil to the disk surface. In particular, recent high-density disks all use thin film disks, so the film strength is not necessarily sufficient, and with conventional loading methods, the long-term reliability of thin film disks is not necessarily sufficient. was there.

tc+ Purpose of the Invention The present invention was devised in view of the above-mentioned drawbacks of the conventional magnetic head loading method.When writing or reading information is stopped, the disk medium and the magnetic head are completely out of contact with each other. The function of quickly loading the magnetic head to a predetermined flying height without a complicated mechanism eliminates wear and tear caused by sliding between the disk medium and the magnetic head.
An object of the present invention is to provide a magnetic head loading method that prevents adsorption.

(d) Structure and object of the invention According to the present invention, there is provided a negative pressure slider that includes a magnetic head and draws the magnetic head to a predetermined height above a disk-shaped recording medium using negative pressure, and a negative pressure slider that has one end of the negative pressure slider. a gimbal for supporting the gimbal; a head arm for fixing the other end of the gimbal; an actuator for moving the head arm; and a control circuit for driving the actuator to position the magnetic head at a predetermined position on a disk-shaped recording medium. In the magnetic gutter movement device, the initial height of the negative pressure slider above the recording medium is set to be larger than the retracting height, and the actuator is moved to the slider.
A means for vibrating in the theta direction near the natural frequency of the gimbal system is provided, and the excitation means is activated when the recording medium reaches a predetermined rotational speed, thereby causing the slider and the gimbal system to resonate and drive the magnetic head. This is achieved by a magnetic head loading method characterized by loading the magnetic head to the retracted height.

(81st Embodiment of the Invention Hereinafter, one embodiment of the magnetic head loading method according to the present invention will be described in detail with reference to the drawings.

FIG. 1 is a schematic perspective view of a negative pressure slider to which such an embodiment is applied. In the figure, the slider 4 includes a positive pressure generating section 41 called a sight rail, a cross rail 42, and a negative pressure generator that generates a negative pressure that acts to attract a magnetic head 45 to the disk medium in the area behind the cross rail 42. Section 43
It is composed of.

As shown in FIG. 2, the slider 4 is attached to the head arm 2 via a gimbal 3 made of a flexible leaf spring at a height hO from the disk medium l, and seeks in the direction of the arrow a in the figure. .

FIG. 3 is a view of the slider shown in FIG. 2 in the direction of arrow A, and the slider 4 is mounted obliquely at an angle of δ with respect to the surface of the disk medium. This is to generate more negative pressure in the negative pressure generating section 43 than during retraction,
By setting this angle, the retraction height hl can be made larger. Furthermore, once loaded, the slider posture becomes stable due to self-stability, which is almost parallel to the disk surface, as shown by the broken line in the figure. Note that in the figure, arrow B indicates the direction of air flow that occurs as the disk medium l rotates.

In the present invention, prior to the current seek operation, the arrow a
By vibrating the slider 4 in the theta direction at a certain frequency, the slider 4 is loaded to the position shown by the broken line. The operation at this time will be explained with reference to the characteristic diagram shown in FIG. 4 showing the self-suction property of the negative pressure slider.

That is, in the same figure, the solid line Fl indicates positive pressure,
The broken line F2 is the negative pressure, and the dashed line F3 is the spring force.Since the dependency on the height of the floating blade is smaller for the negative pressure, the positive pressure becomes almost 0 at a certain height, and the negative pressure is softer than the spring force. If it is large, it will be loaded, but the height hl at this time is generally very small, about several tens of μm. In a general device, it is difficult to load only by ensuring the dimensions and accuracy of the above-mentioned mechanism. Therefore, as shown in the relationship between the peripheral speed of the disk and the flying height of the slider during all operations from unloading to loading of the magnetic head in FIG. In the present invention, the area between the retraction heights hl is compensated for by forced excitation force. In the same figure, after the magnetic head starts rotating, loading is performed in the steps ①-②-■, and information is written and read in ①. On the other hand, when the rotation stops, the disk decelerates and ■
The point where the spring force exceeds the negative pressure (Vs
), unloading (■) is performed naturally, and the height (ho) at the time of stop is restored.

FIG. 6 is a characteristic diagram of experimental values of the frequency characteristics of the transfer function of arm acceleration to slider tip acceleration when the gimbal system is vibrated in the vertical direction.

The frequency ωO is the natural frequency due to the mass m of the slider 4 and the stiffness k of the leaf spring 3, and ωO= (1/2π)(r[7
It is generally a low frequency of several tens of square meters to about 10,011 z. In this resonance, the gimbal 3
Since is a metal leaf spring, the damping is smaller than that of W. Therefore, the peak gain AO is quite large, 30db~
It reaches 40db.

Figure 7 is a transfer function diagram of horizontal acceleration versus vertical acceleration when the actuator that vibrates Herad arm 2 is vibrated in the theta direction. It is not 0 but has a gain AI.

From Fig. 6 and Fig. 7, A= (hO-hl) / (AOXAI) ---
−(Load is established if the amplitude given by equation 11 is given to the actuator.Also, even if an ideal actuator exists and AI=0, the gimbal 3 made of a leaf spring is initially By giving the set angle θ, A≧(hOLl) / (SinθX AO)------ by the component of the inertial force acting on the mass of the slider 4
--(By giving the amplitude of Equation 21, the load is still established. In this case, to show an actual numerical example, hO' = 0
．． 2 dragons, hl-0,05n+, AO=34db (5
0 times), θ = 5°, ω0 = 10011z, A≧
0.034 tuna (in the case of a sine wave), and the acceleration Aω2 at this time is 1.4 G. This also applies to (1) above.
In the formula, AI'=-22db is also almost equivalent. In any case, it can be seen that vibrations with a fairly small amplitude are sufficient, and even a small acceleration of several tenths of the magnitude of the acceleration during actual seeking is sufficient.

To summarize the above, in an actuator with a large acceleration in the vertical direction, θ may be 0, and in an actuator with a small acceleration, loading is always possible by giving an angle θ.

In addition, since resonance is used, the posture of the slider is disturbed during transients, and there is a risk that it may come into partial contact with the disk medium, but in reality, when the pull-in height h1 or less, the suction force is suddenly activated, and this suction force is Since it acts almost at the center of the slider, the self-stability of the posture is extremely good, and the positive pressure in the low-flying area is also large, so there is little possibility of this happening.

Once you enter the area where the aerodynamic force below hl is dominant,
Since the stiffness of the air film is incomparably greater than that of a leaf spring, the resonance is almost suppressed and there is almost no adverse effect on the subsequent seek operation.

Next, FIG. 8 shows a block diagram of the actuator control circuit of the present invention.

In the figure, a normal actuator control section 25 feeds back a position signal from a servo demodulation circuit 24 and instructs a power amplifier 22 about the current value to be passed through the actuator 21. Moreover, the control system 2 for loading of the present invention
6 is controlled by a timer together with the actuator control section 25. The switching means 23 is constituted by, for example, an analog switch.

FIG. 9 is a block diagram showing an example of the configuration of the loading control system 26, which includes a noise source 31, a voltage amplifier 32 for amplifying the noise signal from the noise source, and a band pass tuned to the natural frequency ωO. The filter 33 generates peak noise near the resonance point of the gimbal system and applies it to the power amplifier 22. The reason why the peak noise is used instead of the sine wave is that the frequency ω0 corresponding to the resonance point of the gimbal system may vary due to dimensional tolerances and other factors. Of course, this part may be a swept sine wave oscillator or the like with a limited frequency band.

Next, the loading control operation will be explained with reference to the explanatory diagram of the control sequence shown in FIG. 10, which shows changes in the rotational speed after the rotation of the disk medium starts.

That is, at the time t when the rotational speed reaches fl after the start of rotation, the peak noise signal is applied to the actuator to cause it to vibrate, thereby loading the magnetic head. Then, after the time ti when the rated rotational speed fo is reached, the switch 23 is automatically switched to the actuator control section 25 side, and thereafter the disk device operates in exactly the same way as a normal disk device.

Note that the control operation described above operates completely in an open loop, so the position at which the slider is vibrated tends to be unstable. However, in reality, the tensile force of the attached cable acts, and the slider moves around the inner and outer peripheries of the disk. In either case, by giving a slight offset to the signal, it is possible to move and vibrate to the stopper positions provided to represent the inner and outer circumferential ends. Further, since the moving acceleration of the slider is low, there is no particular adverse effect even if the slider collides with the stopper.

(f) Effects of the Invention As is clear from the above description, the present invention can load and unload the magnetic head using a simple mechanism, thereby avoiding wear and damage to the disk medium and the magnetic head. A magnetic disk device with longer life and higher reliability can be realized.

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing a schematic configuration of a negative pressure slider to which the present invention is applied, FIG. 2 is a diagram for explaining one embodiment of the present invention, and FIG. 3 is a left side view of FIG. Figure 4 is a characteristic diagram for explaining the self-attracting property of the negative pressure slider, and Figure 5 is a diagram showing the relationship between the circumferential speed of the disk medium and the flying height of the head during all operations from unloading to loading of the magnetic head. , Figure 6 is a characteristic diagram based on experimental values of the frequency characteristics of the transfer function of arm acceleration to slider tip acceleration when the gimbal system is excited in the vertical direction, and Figure 7 is a graph of the actuator that excites the Herad arm in theta. FIG. 8 is a block diagram of the actuator control circuit according to the present invention, FIG. 9 is a configuration diagram of an example of a disk control system, and FIG. FIG. 3 is a diagram for explaining a control sequence of a control system. In the figure, 1 is a disk medium, 2 is a helad arm, 2
1 is an actuator, 22 is a power amplifier, 23 is a switching means, 24 is a servo demodulation circuit, 25 is an actuator control section, 26 is a control system, 3 is a gimbal, 31 is a noise source, 32 is a voltage amplifier, 33 is a bandpass filter , 4 is a slider, 41 is a positive pressure generating part, 42 is a cross rail,
Reference numeral 43 indicates a negative pressure generation area, and reference numeral 44 indicates a magnetic head. Figure 1 1, F Figure 3 Figure 4 FM 5 Flash Figure 6; Figure 7 LLIo Mark Iff number log ω #S9 Figure

Claims (1)

[Claims] a negative pressure slider that contains a magnetic head and draws it to a predetermined height above a disk-shaped recording medium using negative pressure; a gimbal that supports the negative pressure slider at one end; and a head that fixes the other end of the gimbal. In a magnetic head moving device comprising an arm, an actuator that moves the head arm, and a control circuit that drives the actuator to position the magnetic head at a predetermined position on a disk-shaped recording medium, the recording medium of the negative pressure slider The initial height of the top is set to be larger than the retraction height, and means is provided for vibrating the actuator in the theta direction near the natural frequency of the slider and gimbal system, and the excitation means is set such that the recording medium rotates at a predetermined rotation speed. A magnetic head loading method characterized in that the magnetic head is loaded to the retracting height by operating the slider and gimbal system when the height is reached.