JP3180356B2 - Magnetic disk drive - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic disk drive.

[0002]

2. Description of the Related Art In a magnetic disk drive, information is written and read while a slider having a magnetic head is slightly floated above the surface of a magnetic disk. The slider flies above the surface of the magnetic disk by an airflow generated on the surface of the magnetic disk by rotation of the magnetic disk.

A contact start / stop method is used as a loading method of a conventional magnetic disk drive. In the contact start / stop method, the magnetic disk starts rotating at startup,
The rotation speed of the magnetic disk becomes smaller than a predetermined rotation speed until the rotation speed of the magnetic disk reaches a certain rotation speed and the slider flies due to the airflow on the magnetic disk and separates from the magnetic disk, and immediately before the stop. During the period from when the slider is lowered onto the magnetic disk to when the rotation of the magnetic disk is completely stopped, the slider contacts the magnetic disk and slides on the magnetic disk. Therefore, in this method, when the magnetic disk starts and stops, the slider and the magnetic disk slide with each other, so that there is a great risk that the surface of the slider or the magnetic disk may be damaged.

In the contact start / stop method, the slider and the magnetic disk slide when the magnetic disk starts and stops, so that a contact start / stop area (hereinafter referred to as a shipping zone) is provided. No data was recorded in the shipping zone for data protection. For this reason, the recording capacity of data is reduced by the amount of the shipping zone, which hinders realization of a high recording capacity.

[0005] Therefore, from the start of rotation of the magnetic disk until the rotation reaches a predetermined rotation speed and until the rotation speed of the magnetic disk becomes lower than the predetermined rotation speed and stops.
A load / unload method has been studied in which the slider is separated from the magnetic disk so that the slider and the magnetic disk do not slide.

Next, a conventional magnetic disk drive device having a load / unload method will be described. FIG.
1 is a perspective view showing a conventional magnetic disk drive.

In FIG. 6, reference numeral 1 denotes a flexure constituted by a leaf spring. The flexure 1 is fixed to a carriage arm 4 which is movable in a direction crossing a data track recorded on a magnetic disk 5. Reference numeral 2 denotes a gimbal formed by a thin plate provided at the tip of the flexure 1. 3
Is a slider having a magnetic head, and a slider 3 is fixed to the flexure 1 via a gimbal 2. The gimbal 2 is provided to make the slider 3 follow the undulation of the magnetic disk 5.

Reference numeral 6 denotes a load pin provided on the opposite side of the flexure 1 from the magnetic disk 5 side so as not to contact the flexure 1 and apart from the flexure 1 and attached to the support arm 7. Reference numeral 8 denotes a solenoid for driving the support arm 7 toward the magnetic disk 5. When loading the slider 3 onto the magnetic disk 5, the support arm 7 loads the load pin 6 attached to the support arm 7.
As a result, the flexure 1 is displaced toward the magnetic disk 5. The driving of the support arm 7 is performed by supplying a constant current to the solenoid 8 and changing the iron core of the solenoid 8 from the projected state to the retracted state.

As described above, the support arm 7 is connected to the magnetic disk 5
The load pin 6 attached to the support arm 7 presses the flexure 1 to bend the flexure 1 toward the magnetic disk 5 by moving the slider 3 toward the rotating magnetic disk 5, The slider 3 can be levitated above the magnetic disk 5.

[0010]

At present, very few magnetic disk drive devices are equipped with a slider loading mechanism. The reason is that if the loading and unloading operations of the slider are repeatedly performed in the conventional configuration, a head crash may occur, and as a result, the reliability of the magnetic disk drive device cannot be secured.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and has as its object to provide a magnetic disk drive device provided with a load means for loading a slider onto a magnetic disk without causing a head crash. An object of the present invention is to provide a highly reliable magnetic disk drive.

[0012]

In order to solve this problem, the present inventor has sought to find a cause of a head crash by repeatedly loading and unloading a slider on a magnetic disk in the above-mentioned conventional configuration. . As a result, the following two points were found to be the causes of the head crash.

The first cause is the loading posture of the slider at the moment when the slider is loaded on the magnetic disk. When the slider is loaded on the magnetic disk in the conventional configuration, the magnetic disk facing surface of the slider is maintained substantially parallel to the magnetic disk.
In some cases, the attitude of the slider could not be recovered. In other words, in the conventional loading / unloading operation, the iron core of the solenoid is in a stable state only in the two states of the protruding state and the retreating state. In some cases, it was not possible to maintain a state substantially parallel to the above. Accordingly, the surface of the slider facing the magnetic disk is approached to the magnetic disk while being inclined with respect to the magnetic disk. For this reason, before the slider reaches the flying position, the slider contacts the magnetic disk without generating a sufficient positive pressure, and damages the slider and the magnetic disk, causing a head crash.

The second cause is dust generated from a sliding portion of a loading mechanism for loading a slider onto a magnetic disk. When the slider is loaded on the magnetic disk in the conventional configuration, the iron core of the solenoid is in a stable state only in the two states of the protruding state and the retracted state. Therefore, the loading operation of the slider is performed quickly, and the iron core of the solenoid is A large force is applied to the sliding part of. For this reason, a large amount of dust was generated from the sliding portion of the iron core of the solenoid, and the generated dust entered the flying gap between the slider and the magnetic disk, causing a head crash.

An object of the present invention is to provide a highly reliable magnetic disk drive which does not cause a head crash based on the above-mentioned knowledge on the conventional problems.
The control unit controls the flexure drive speed of the load unit that brings the flexure closer to the magnetic disk by controlling the magnitude of the current supplied to the load unit, thereby lowering the drive speed of the loading mechanism.

[0016]

According to the present invention, when the slider is to be brought close to the magnetic disk when the magnetic disk drive is started, the slider can be brought very close to the magnetic disk at a very low speed. The slider can recover its attitude while being maintained substantially parallel to the magnetic disk. Therefore, during loading, the slider can float on the magnetic disk in a stable flying posture, and the slider 3 and the magnetic disk 5 do not come into contact with each other, thereby preventing the slider 3 and the magnetic disk 5 from being damaged. Further, since the speed at which the iron core of the solenoid 8 is displaced from the protruding state to the retreating state or from the retreating state to the protruding state is reduced, a large force is not applied to the sliding portion of the solenoid 8. As a result, dust generated from the sliding portion of the loading mechanism can be reduced, head crashes due to dust generated from the sliding portion of the loading mechanism can be eliminated, and a highly reliable magnetic disk drive device having a large recording capacity can be provided. be able to.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a configuration diagram of one embodiment of the present invention. In FIG. 1, a flexure 1, a gimbal 2, a slider 3, a carriage arm 4, a magnetic disk 5, a load pin 6, and support arms 7, 8 are solenoids which are driving mechanisms of a load means.
Is the same as Reference numeral 9 denotes a control unit that controls a current value supplied to the solenoid 8.

Next, FIG. 2 shows an operation of loading the slider of this embodiment. First, when the magnetic disk 5 is not rotating, since no current is supplied to the solenoid 8, the iron core 8 of the solenoid 8 as shown in FIG.
0 maintains the protruding state. Therefore, the support arm 7 is located at a position separated from the magnetic disk 5, and the magnetic disk 5 and the slider 3 are separated from each other. The load pin 6 and the flexure 1 are also separated.

Next, after the magnetic disk 5 starts to rotate and reaches a predetermined number of revolutions, when current is supplied to the solenoid 8, the support arm 7 starts to move in the direction of the magnetic disk 5. When the current supplied to the solenoid 8 is slowly increased, the support arm 7 moves at a low speed in the direction of the magnetic disk 5 so that the load pin 6 attached to the support arm 7 contacts the flexure 1 and the flexure 1 is moved to the magnetic disk 5. Press and bend to the side. This state is shown in FIG.

Further, when the current supplied to the solenoid 8 is increased, the load pin 6 pushes the flexure 1 up to a predetermined position. As a result, a dynamic pressure is generated on the slider 3, and the slider 3 flies above the magnetic disk 5. At this time, when a negative pressure type slider is used as the slider 3, the combined force of the positive pressure generated on the slider 3 for pushing up from the magnetic disk 5 and the force of the flexure 1 for separating the slider 3 from the magnetic disk 5 is generated by the magnetic disk. The slider 3 is maintained at a constant distance from the magnetic disk 5 at a position where the slider 3 is balanced with the force acting to be attracted toward the magnetic disk 5 by the negative pressure of 5, so that the slider 3 and the magnetic disk 5 stably fly without contacting each other. State can be maintained.

After the loading operation of the slider 3 onto the magnetic disk 5 is completed, the current supplied to the solenoid 8 is slowly reduced, and the support arm 7 is moved at a low speed in a direction opposite to the magnetic disk 5. This state is shown in FIG.
It is shown in (C).

As shown in FIG. 3, the configuration of the solenoid driving control section 9 is as follows.
And the current amplifier 11. When the step signal of the solenoid drive command shown in FIG. 4A is given as an input signal to the low-pass filter 10 constituting the solenoid drive control unit 9, the output of the low-pass filter 10 is shown in FIG. As described above, the waveform is processed into a signal that gradually rises or falls with a time constant determined by the values of the resistance and the capacitor that constitute the low-pass filter 10. By inputting the waveform-processed signal to the current amplifier 11, the speed at which the iron core 80 of the solenoid 8 is displaced from the protruding state to the retracted state or from the retracted state to the protruding state can be controlled.

As described above, when the slider 3 is lowered onto the magnetic disk 5, the current value supplied to the solenoid 8 is controlled by the control unit 9, and the driving speed of the flexure of the load means is adjusted. 3 can be controlled to descend onto the magnetic disk 5.

Therefore, according to the present embodiment, when the slider 3 is lowered onto the magnetic disk 5, the current value supplied to the solenoid 8 is controlled so that the speed at which the slider 3 is lowered onto the magnetic disk 5 is reduced. By controlling the slider, the attitude of the slider can be recovered so as to maintain the surface of the slider facing the magnetic disk substantially parallel to the magnetic disk.
Therefore, since the slider can fly above the magnetic disk in a stable flying posture, the slider can be loaded onto the magnetic disk without bringing the slider into contact with the magnetic disk. As a result, the slider 3 does not come into contact with the magnetic disk 5 to cause a head crash or destroy data, and high reliability of the magnetic disk drive device can be secured.

The current value supplied to the solenoid 8 is
By controlling the driving speed of the solenoid 8, the speed at which the iron core 80 of the solenoid 8 is displaced from the protruding state to the retracted state or from the retracted state to the protruding state is reduced, so that a large force is applied to the sliding portion of the solenoid 8. As a result, dust generated from the sliding portion of the solenoid 8 can be reduced. Therefore, dust generated from the sliding portion of the solenoid 8 does not cause a head crash and destroy data, and high reliability of the magnetic disk drive device can be secured.

Next, in order to verify the effect of this embodiment,
In the conventional example, that is, the current supplied to the solenoid 8 for driving the loading means of the slider to the magnetic disk is continuously increased at the start of driving, and is continuously decreased before the end of driving. Test results comparing the present embodiment with a magnetic disk drive device not shown will be described. Further, in driving the solenoid using this embodiment, the current is continuously increased so that the current becomes 0.5 A 4 seconds after the start of driving the solenoid, and then the current is continuously reduced to start driving the solenoid. After 7 seconds, the supply of current was stopped.

The test conditions were a temperature of 25 ° C. and a relative humidity of 60%.
The loading and unloading of the slider onto the magnetic disk was performed 50,000 times in the environment described above. Then, dust generated from the sliding portion of the loading mechanism during the test was measured using a dust counter. After the test was completed, microscopic observation of scratches generated on the slider and the magnetic disk due to loading and unloading operations of the slider on the magnetic disk was performed.

FIG. 5 shows the comparison results. FIG. 5 shows a measurement result obtained by measuring dust generated from the sliding portion of the loading mechanism using a dust counter when the slider is loaded and unloaded onto the magnetic disk 50,000 times. In FIG. 5, the horizontal axis represents the number of loadings, and the vertical axis represents the number of dusts generated in one loading operation. The plot indicated by a black circle indicates the current supplied to the solenoid 8 for driving the load means. In the case of the conventional magnetic disk drive device in which the current is not controlled so that the current is increased and the current is continuously decreased before the driving is completed, a plot of a square mark indicates to the solenoid 8 for driving the loading mechanism. This is the case of the magnetic disk drive device of the present embodiment in which the supplied current is continuously increased at the start of driving and is continuously reduced before the end of driving.

In the prior art, current control is not performed such that the current supplied to the solenoid 8 for driving the loading mechanism is continuously increased at the start of driving and is continuously decreased before the driving is completed. Therefore, the speed at which the iron core 80 of the solenoid 8 is displaced from the protruded state to the retracted state or from the retracted state to the protruded state is increased. Therefore, before the momentum exerts sufficient buoyancy on the slider 3, the slider 3 comes into contact with the magnetic disk 5 for a moment. Further, since the speed at which the iron core 80 of the solenoid 8 is displaced from the projected state to the retracted state or from the retracted state to the extended state is high, a large force is applied to the sliding portion of the solenoid 8. Therefore, a large amount of dust is generated from the sliding portion of the solenoid 8.

On the other hand, in the present embodiment, the current supplied to the solenoid 8 for driving the loading mechanism is increased continuously at the start of driving, and is decreased continuously before the end of driving. Since the control is performed, the speed at which the iron core 80 of the solenoid 8 is displaced from the projected state to the retracted state or from the retracted state to the extended state can be made extremely low. Therefore, when the slider 3 is loaded on the magnetic disk 5, the slider 3 does not contact the magnetic disk 5.

Further, since the speed at which the iron core 80 of the solenoid 8 is displaced from the projected state to the retracted state or from the retracted state to the extended state can be made extremely low, a large force is not applied to the sliding portion of the solenoid 8. For this reason, dust generated from the sliding portion of the solenoid 8 can be reduced. If the number of dust generated from the sliding portion of the solenoid 8 is small, it can be removed by a circulation filter provided in the magnetic disk drive.

After the test, the slider and the magnetic disk were observed under a microscope by loading and unloading the slider onto and from the magnetic disk. As a result, in this embodiment, no damage was found on the slider and the magnetic disk. That was confirmed.

Thus, it can be seen that this embodiment is superior to the conventional example. As described above, by controlling the magnitude of the current supplied to the solenoid 8, the loading speed of the slider 3 onto the magnetic disk 5 is made extremely low, so that a large force is applied to the sliding portion of the solenoid 8. Therefore, dust generated from the sliding portion of the solenoid 8 can be reduced, and the slider 3 can be loaded without contacting the magnetic disk 5. Accordingly, head crashes due to dust and scratches on the slider 3 and the magnetic disk 5 are eliminated, thereby improving the reliability of the magnetic disk drive.

In the present embodiment, the current control section of the slider loading mechanism is constituted by the low-pass filter 10 and the current amplifier 11. However, for example, even if the control is performed by a microcomputer using a digital / analog converter, It is only necessary to be able to perform current control such that the current supplied to drive the loading mechanism is continuously increased at the start of driving, and is continuously reduced before driving is completed to end driving. Not even. Further, in the present embodiment, the solenoid 8 is mounted on the loading mechanism of the slider 3.
However, it goes without saying that other configurations may be used as long as the loading speed of the slider 3 onto the magnetic disk 5 can be controlled by current control.

[0035]

As described above, according to the present invention, by controlling the driving speed of the loading means to a low speed by the control unit,
Since a large force is not applied to the loading means, dust generated from the loading means can be reduced, and the attitude of the slider can be recovered so that the surface of the slider facing the magnetic disk is maintained substantially parallel to the magnetic disk. .
Therefore, the slider can fly above the magnetic disk in a stable flying posture, and can be loaded without bringing the slider into contact with the magnetic disk. Therefore, head crashes due to dust and scratches on the slider and the magnetic disk are eliminated, so that the reliability of the magnetic disk drive is improved.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a main part of an embodiment of the present invention.

2A is an explanatory view showing a state in which the slider of the embodiment is at an upper position; FIG. 2B is an explanatory view showing a state in which the slider of the embodiment is at an intermediate position; Explanatory drawing showing the state at the position

FIG. 3 is a block diagram of a control unit according to the embodiment.

FIG. 4A is a voltage waveform diagram of a solenoid drive command input to a control unit, and FIG. 4B is a current waveform diagram of a current supplied to the solenoid output from the control unit.

FIG. 5 is a diagram showing test results of the number of generated dusts in the conventional example and this embodiment

FIG. 6 is a perspective view showing a conventional magnetic disk drive device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Flexure 2 Gimbal 3 Slider 4 Carriage arm 5 Magnetic disk 6 Load pin 7 Support arm 8 Solenoid 9 Control part 10 Low-pass filter 11 Current amplifier

Continuation of front page (58) Field surveyed (Int.Cl. ⁷ , DB name) G11B 21/12

Claims (1)

(57) [Claims] 1. A magnetic disk, a carriage arm that moves substantially parallel to the magnetic disk, a flexure attached to the carriage arm, and a negative electrode provided on the flexure and floating on the rotating magnetic disk. Comprising a pressure type slider and a load pin that moves up and down,
Load the negative pressure slider perpendicular to the magnetic disk surface.
Loading means for loading the load pin
Descends and depresses the flexure, and the flexure
The negative pressure type slider provided on the magnetic disk.
Causes the above, the loading operation is finished after floating the negative pressure type slider on the magnetic disk, the load
A load means for raising the pin , comprising: a control unit for lowering the flexure drive speed of the load means by current control, wherein the control unit controls a current supplied to the load means. A magnetic disk drive device wherein the negative pressure slider is gently loaded onto a magnetic disk by controlling the current so as to increase continuously at the start of driving and to decrease continuously before the end of driving.