JPH0281379A - Head/disk adhesive release method - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a mechanism for releasing adhesion between a magnetic head and a disk, and in particular to a circuit that controls a sequence for effectively releasing adhesion in a simple system, and a circuit necessary therefor. related to sensors.

[Conventional technology]

Conventional devices are not equipped with a desticking mechanism, so when sticking occurs, it is inevitable that the head or disk will be damaged. Thereafter, an operation to release the adhesive after it has occurred can be considered, for example,
As described in Japanese Patent No. 5, an attempt was made to remove the adhesion by moving the head a small distance in the radial direction of the disk.

[Problem that the invention seeks to solve]

However, the above-mentioned conventional technology lacks a certain degree of reliability in releasing the adhesive, and there is a considerable risk of damage to the head or disk. The reason for this is that when -degree adhesion occurs, simple movement in the radial direction of the disk causes only a unidirectional shear force to act on the adhesive interface, making it difficult to apply large stress and making it difficult for peeling to progress.

SUMMARY OF THE INVENTION An object of the present invention is to provide a device that can reliably release adhesive when it occurs.

[Means to solve the problem]

The above purpose is to effectively promote adhesive peeling with a small force by applying torsional mode stress to the adhesive interface. When combined with vibration, the relative motion between the head and the disk is set to a motion that includes a torsional mode at the interface between the two, thereby effectively achieving adhesion separation (release).

[Effect]

A controlled by the VCM that drives the head actuator and the spindle motor that drives disk rotation.
When C is applied, the head actuator vibrates the head in the radial direction of the disk, and the spindle motor vibrates the disk in the rotational direction. Since the directions of each vibration are perpendicular to each other, when both vibrations are applied at the same time, the direction of head movement of the combined vibration will draw a Lissajous according to the combination of the amplitude and phase difference of both vibrations. By appropriately setting the vibration conditions, it is also possible to cause the relative motion of both the head and the disk to include a torsion mode at the interface.

When the head and disk move relative to each other due to this movement, cracks occur at the interface between the lubricant on the disk or the moisture adhesive film and the outside air, which causes the two to stick together, making the film more likely to break. . The torsional stress at this time has a value smaller than the tensile stress and shear stress between the head and the disk.

〔Example〕

An embodiment of the present invention will be described below with reference to the drawings. 1st
The figure schematically illustrates the principle of the present invention. Figure 1 shows only the relationship between heads and disks in a magnetic disk device, including a plurality of magnetic heads 1, a VCM 2 for moving them, a power amplifier 5 for VCM & driving, and a transmitter. A magnetic disk device comprising circuits 3a and 3b, a control mode switching circuit 4 that switches signals from the transmitting circuit according to a mode switching signal, a motor drive circuit 6, a spindle motor 7, and a plurality of magnetic disks 8. , the signal 9 emitted from the oscillation circuit 3a enters the VCM 2 via the control mode switching circuit 4 and the power amplifier 5, causing the head 1 to vibrate in the disk radial direction according to the input waveform, while the signal 9 emitted from the oscillation circuit 3b The emitted signal 10 enters the spindle motor 7 via the control mode switching circuit 4 and the motor drive circuit 6, and the disk 8 vibrates in its rotational direction according to the input waveform. The direction of vibration of the head and the direction of vibration of the disk are perpendicular to each other as shown in the figure, so depending on the frequency, amplitude, and phase difference of each vibration, the locus of the relative motion between the head and the disk is determined as shown in Figure 2. draws a certain fixed curve (lissage). If there is stickiness between the headset and the disc when the disc stops rotating,
This operation releases the adhesion between the head and the disk, making it possible to perform smooth CS/S.

FIG. 3 is a diagram schematically explaining a second embodiment of the present invention. In the magnetic disk device shown in FIG. 3, which is equipped with a small vibrator 34 that vibrates on its own, inside a casing 35 or externally attached to the casing, the device is vibrated in the in-plane direction of the magnetic disk 33. The whole thing vibrates, and if the disk is not fixed, it will vibrate in the direction of its rotation. By combining this with excitation on the head side similar to the first embodiment, the actuator 32, the magnetic head 31, and the magnetic disk 33 are caused to vibrate relative to each other, and the adhesion between the head and the disk is released.

FIG. 4 is a diagram schematically explaining a third embodiment of the present invention. The input signal for excitation in the rotational direction of the disk in the first embodiment is directly input from the AC power source 43 to the motor drive circuit 45 via the transistor 44. This causes the magnetic disk 41 to vibrate in its rotational direction, and this is combined with the same excitation on the head side as in the first embodiment.

The magnetic head 42 and the magnetic disk 41 move relative to each other, and the adhesion between the header and the disk is released.

FIG. 5 is a diagram schematically showing an embodiment of the invention which is a further development of the present invention. In a magnetic disk device equipped with the above-mentioned adhesion release method, the magnetic head or the magnetic disk spindle is provided with a sensor 51 or 52 that detects the degree of adhesion between the head and the disk, and even though the adhesion release operation is performed. If the sensor detects that the adhesion has not been released, the abnormality detector 53 is activated and an alarm 54 is activated.
A warning is issued to prevent the information recorded on the magnetic disk from being destroyed. As the adhesive sensor 51 provided on the head, for example, as shown in FIG. 6, a strain gauge or the like 63 may be attached to the side surface of a load arm 62 that supports the magnetic head 61. As the adhesive sensor 52 provided on the disk spindle, for example, as shown in FIG.
It is conceivable to provide a torque detector 73 on the disk spindle 71, which is fixed and rotates, to detect the torque at startup. In either case, the abnormality detector is set to operate when the detected signal level exceeds a predetermined threshold level.

FIG. 8 shows an embodiment of a means for increasing the torsional rigidity to which the head is subjected by the adhesive releasing operation. If the conventional method of supporting the slider with a single gimbal spring is used, the detack action tends to cause torsional damage, so a method of connecting the slider and the load arm using a plurality of springs is effective. FIG. 8 shows a method of coupling using three springs. Gimbal springs 81a, 81b, and 81c are attached to the tip of the load arm 8o and bonded to the back surface of the slider. Since the load arm and the slider are supported by the pivot 82, the degree of freedom of movement of the slider is maintained.

FIG. 9 is a diagram schematically showing an example of the sequence at the start of cs/S when the adhesive release method is applied. After powering on the magnetic disk drive, first compare the adhesive force with the T value, which is the threshold value that determines the upper limit of the adhesive. If the adhesive force is greater, then compare the starting torque and the adhesive force. This is done by comparing the values of the adhesion sensor and the torque sensor. If the adhesion force is also a larger value, the adhesion release operation is activated and the above judgment is repeated again. The T value or starting torque is If it exceeds the adhesive force, it will start rotating and enter READY mode.

In the first embodiment of the present invention, the vibrations on the head side and the vibrations on the disk side each have a frequency of several Hz to several kHz and a vibration of several μm to several hundred μm. Each vibration follows a signal emitted from a separate transmitter, but a single transmitter may be used to send the signals to the head side, the disk side, and the disk side with the phases shifted by a certain amount. In addition, the frequency, amplitude, phase difference, etc. of the two oscillators necessary to draw the sharp surge of the head and disk are fed back between each oscillator.

An optimum value may be set.

In one embodiment for increasing the torsional rigidity of the Herad gimbal of the present invention, in order to make the bond between the head and the gimbal difficult to separate, an adhesive with a low rigidity of the adhesive layer after curing is used. The force is relaxed and damage is less likely to occur.

〔Effect of the invention〕

According to the present invention, the adhesion between the head and the disk can be effectively released by providing a simple circuit or device in the magnetic disk device. therefore.

This has the effect of preventing head crashes caused by adhesion, and greatly contributes to improving the quality and reliability of magnetic disk drives.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram of a first embodiment of the present invention, FIG. 2 is a diagram showing an example of relative movement between the head and disk of the first embodiment, and FIG. 3 is a diagram of a second embodiment of the present invention. A diagram schematically explaining the
FIG. 4 is a diagram schematically explaining the third embodiment of the present invention, FIG. Used in Examples. FIG. 7 is a diagram showing an example of a sensor for detecting the degree of adhesion, FIG. 7 is a diagram showing a torque detector used in the embodiment shown in FIG. 5, and FIG. 8 is a diagram showing a means for increasing the torsional rigidity of the head cymbal. FIG. 9 is a diagram schematically showing an example of the sequence at CS/S start of the present invention. Explanation of symbols 1...Magnetic head, 2...VCM, 3a, 3b...
- Transmitter, 7... Spindle motor, 8... Magnetic disk, 31... Magnetic head, 32... Actuator, 33... Magnetic disk, 34... Small exciter, 41...・Magnetic disk, 42...Magnetic head, 4
3... AC power supply, 44... Transformer, 45... Motor drive circuit, 51° 52... Adhesive sensor, 53...
- Abnormality detector, 54... Alarm, 63... Adhesive sensor, 73... Torque detector, 80-... Load arm, 81 a, 8 l b, 81 c - kudzu 7
Map the number of eyes, 1st floor of the square, number 7.

Claims (1)

[Claims] 1. A head/disk device characterized in that adhesion between the head and the disk is released by applying combined vibrations in the disk rotational direction and the head seek direction in the circumferential and radial directions of the magnetic disk. Inter-disk adhesive release method. 2. In the adhesion release method described in claim 1, the amplitude and frequency in the circumferential and radial directions are set so that the shearing force is greater than the adhesion between the head and the disk. Head/disk adhesive release method. 3. A small vibration exciter is built into the magnetic disk drive assembly to generate vibrations in the circumferential direction of the disk.
The head/disk adhesion release method according to claim 1, wherein adhesion is released by combining this with vibration in the head seek direction. 4. The head according to claim 1, wherein vibration in the disk circumferential direction is generated by applying alternating current at a predetermined frequency to the drive motor, and adhesion is released by combining this with vibration in the head seek direction. / Inter-disk adhesive release method. 5. The head/disk adhesion release method according to claim 1, further comprising means for issuing a warning in order to avoid damage to the head or disk if the adhesion is not released. 6. A head/disk adhesion release method, characterized in that the head assembly is provided with means for detecting the degree of head/disk adhesion at the start of CS/S. 7. The head/disk adhesion release method according to claim 6, characterized in that the disk spindle is provided with means for detecting the degree of head/disk adhesion at the start of CS/S. 8. A head/disk adhesion release method characterized in that the head gimbal is formed by a plurality of springs to increase its torsional rigidity.