JPH0337877A - Head floating control method - Google Patents

Abstract

PURPOSE:To prevent crash occurring by holding the air pressure of a recording medium and the sealed container of a head cover atmospheric pressure when a power source is applied, and reducing the air pressure after a head is floated. CONSTITUTION:A control means 6 controls an air pressure control means 5 when the power source is applied, and holds the air pressure of the sealed container over the atmospheric pressure, then, drives a spindle motor 11, and rotates the recording medium 1. After the rotating speed of the motor 11 arrives at prescribed speed, the means 5 is operated, and the air in the container 3 is exhausted. The control means 6 stops the operation of the means 5 at a time when the air pressure arrives at prescribed air pressure, and interrupts the exhaustion of the air. Thereby, the head 2 is quickly floated by increasing the wind pressure of an air current when the power source is applied, and a targeted floating quantity can be maintained by a reducing the air pressure in the container 3 after the head is floated. Therefore, the run-in time of the head with the recording medium can be shortened, and the occurrence of the crash can be reduced.

Description

[Detailed Description of the Invention] [Summary] In a device that records/reproduces data using a head floating above a recording medium, it is possible to reduce the energy consumed while the head rubs against the recording medium. Regarding a head floating control method, the purpose is to make it difficult for crashes to occur, and in an apparatus that seals a recording medium and a head that flies above the surface of the recording medium due to the wind pressure accompanying the movement of the recording medium. The configuration is such that the flying height of the head is controlled by adjusting the air pressure in the airtight container that seals the recording medium and the head.

[Industrial application field]

The present invention relates to an apparatus for recording/reproducing data using a head floating above a recording medium, and more particularly to a head floating control method that makes it possible to reduce the energy consumed while the head rubs against the recording medium. .

A magnetic disk device is a device that records/reproduces data using a head that flies above a recording medium, but with the demand for higher recording density, the rotational speed of the disk medium has increased, and the head Floating height is decreasing.

When the flying height of the head decreases, even if small dust enters between the head's slider, which has a surface that faces the disk medium, and the disk medium surface, scratches will occur on the disk medium surface, and these scratches will cause damage. Dust successively enters between the slider and the disk medium surface, eventually causing a crash that destroys the disk medium surface.

Therefore, recent magnetic disk drives use a disk enclosure (a part of the magnetic disk drive, consisting of a spindle, a disk, an access arm, a linear motor, etc.) that is sealed to prevent dust from entering.

Incidentally, in a magnetic disk drive, when the disk medium is not rotating, the head is in contact with the disk medium, and the slider is configured to float due to the wind pressure of the airflow generated as the disk medium rotates. . Therefore, during the period from when the disk medium starts rotating to when the head floats,
The slider and the disk medium surface rub against each other from the time when the rotational speed of the disk medium decreases and the head comes into contact with the disk medium surface again until the disk medium stops.

Therefore, by shortening this rubbing time and reducing the energy consumed during rubbing,
It is necessary to prevent crashes from occurring due to dust caused by damage to the disk medium.

[Conventional technology]

Conventionally, in order to reduce the flying height of the head, it was necessary to increase the spring pressure of the head spring that attaches the head/nod to the arm of the carriage to counteract the wind pressure of the airflow that accompanies the rotation of the disk medium, or to lower the flying height. The width of the slider is narrowed to reduce the surface of the slider that faces the disk medium,
A method is used to reduce the flying height by reducing the wind pressure applied to the slider.

[Problem to be solved by the invention]

However, because of this, the pressure on the slider surface increases when the head is in contact with the disk medium surface, and the rotation of the disk medium decreases until the disk medium starts rotating and the head flies up. After the head comes into contact with the disk medium again until the rotation of the disk medium stops,
Compared to a head that has a small pressure on the slider surface, the slider surface is rubbed against the disk medium surface with a large amount of energy, so there is a problem that crashes are more likely to occur.

Additionally, if the slider is pressed against the disk medium surface with great pressure, the head will stick due to the influence of the disk medium's surface treatment agent, and the spindle motor will not start when the power is turned on, making it difficult to rotate the disk medium. There is a problem in that it is necessary to provide a function that shakes the head when the power is turned on so that the spindle motor can start.

In view of these problems, the present invention makes it possible to reduce the pressure on the slider surface when reducing the flying height.
The purpose is to make it less likely to crash and to avoid adding extra functionality.

[Means to solve the problem]

FIG. 1 is a diagram illustrating the present invention in detail.

The airtight container 3 hermetically seals the recording medium 1 and the head 2, and is configured such that the internal air pressure is controlled by an air pressure control means 5. An air current is generated along with the movement of the recording medium 1, and when this air current flows to the slider surface of the head 2, the gutter 2 is caught by the wind pressure and floats away from the recording medium 1.

When the air pressure control means 5 exhausts the air in the closed container 3, the air pressure decreases, the air becomes thinner, and the wind pressure of the airflow generated by the movement of the recording medium 1 decreases, so that the flying height of the head 2 decreases. Therefore, the flying height of the head 2 is controlled by the exhaust from the air pressure control means 5.

When recording/reproducing data on the recording medium I with the recording medium l and the head 2 sealed, a spindle motor 11 for rotating the recording medium l, a carriage 9 to which the head 2 and the servo head 10 are attached, and this A motor 8 is provided in the closed container 3 for moving the carriage 9 and positioning the head 2 and servo head 10 at the target cylinder.

When the power is turned on, the control means 6 controls the air pressure control means 5 to maintain the air pressure inside the sealed container 3 at or above atmospheric pressure, and then drives the spindle motor 11 to rotate the recording medium I. After the rotational speed of the spindle motor 11 reaches a predetermined rotational speed, the air pressure control means 5 is operated,
The air inside the airtight container 3 is exhausted.

When the air pressure inside the airtight container 3 decreases, the wind pressure of the airflow generated as the recording medium 1 rotates decreases because the air becomes thinner, and the flying height of the head 2 also decreases. Control means 6
When the atmospheric pressure reaches a predetermined value, the operation of the atmospheric pressure control means 5 is stopped, and the evacuation of the airtight container 3 is stopped.

After stopping the evacuation, the control means 6 sends a ready signal to the host device, and in response to an instruction from the host device, sends an address to the servo means 7 to position the head 2 at the target cylinder and activates it.

The servo means 7 drives the motor 8 to move the carriage 9 based on the servo information read by the servo head 10.
Position the head 2 on the target cylinder.

[Effect]

With the above configuration, the air pressure control means 5 maintains the air pressure inside the sealed container 3 at a level higher than the atmospheric pressure when the power is turned on, so that the wind pressure of the airflow accompanying the 10 rotations of the recording medium is strong, and the head 2 rises rapidly. becomes possible. When the head 2 floats up, the air pressure control means 5 is controlled to reduce the air pressure inside the sealed container 3, so the wind pressure of the airflow accompanying the rotation of the recording medium 1 becomes weaker, and the head 2, which has floated higher, is lowered. This makes it possible to maintain the desired flying height.

Therefore, the spring pressure of the heladium spring 12 of the head 2 can be lowered, and the slider surface can be made wider. Therefore,
In addition to reducing the energy generated when the head 2 rubs against the recording medium surface to prevent the occurrence of a crash, it also prevents the head 2 from sticking to the recording medium 1, making it unnecessary to add extra functions. .

〔Example〕

FIG. 2 is a block diagram of a circuit showing one embodiment of the present invention.

When the power is turned on, the switch circuit 16 sends current from a power source (not shown) to the vacuum pump 17 to open the exhaust valve (not shown) of the vacuum pump 11 . Therefore, when the pressure inside the closed container 3 is lower than atmospheric pressure, air passes through the filter 18 for removing dust, passes through the vacuum pump 17, and enters the closed container 3.

The control circuit 21 starts the drive circuit 20, and the started drive circuit 20 rotates the spindle motor 11. The drive circuit 20 monitors the rotational speed of the spindle motor 11 and controls the current supplied to the spindle motor 11 so as to maintain a specified rotational speed of, for example, 3600 revolutions/minute.

When the spindle motor 11 rotates, the recording medium 1 also rotates, and when the rotational speed of the recording medium 1 increases, the head 2
The servo head 10 is lifted up from the surface of the recording medium 1 by wind pressure.

When the power is turned on, head 2 and servo head 10 are connected to recording medium 1.
The servo circuit 19 supplies current to the motor 8 to connect the head 2 and the servo head 10.
The carriage 9 is driven so that it does not deviate from the retraction area.

Therefore, the head 2 reads data recorded in advance in the save area of the recording medium 1 and sends it to the amplifier circuit 14.

When the rotational speed of the spindle motor 11 sent out by the drive circuit 20 reaches a predetermined rotational speed, the control circuit 21 enables the amplifier circuit 14 and the comparison circuit 15, and sets the level of the data sent out by the amplifier circuit 14 to 0. Compare circuit 1
Compare to 5.

By the time the spindle motor 11 reaches a predetermined rotational speed, the head 2 has risen to its highest flying height under atmospheric pressure, so the level of data read by the head 2 from the recording medium 1 is low. Therefore, when the comparison circuit 15 compares the thresholds ■ and ■2 with the data level ■0, V>
If Vt, then Vt>V.

Therefore, the comparator circuit I5 sends a signal to the switch circuit 16, and the switch circuit 16 stops supplying the current from the power supply to open the exhaust valve, and causes the vacuum pump 17 to supply current for performing the exhaust operation. Therefore, the air inside the closed container 3 is exhausted from the vacuum pump 17 through the filter 18, and the air pressure is reduced.

When the air pressure inside the airtight container 3 decreases, the wind pressure of the airflow accompanying the rotation of the recording medium 1 decreases, so the flying height of the head 2 decreases and the distance from the recording medium 1 decreases, causing the data read by the head 2 to decrease. level increases. Therefore, amplifier circuit 1
The level of data sent by 4 becomes high, ■. ≧■1
When this happens, the comparison circuit 15 sends a signal to the switch circuit 16, which cuts off the current being supplied to the vacuum pump 17 and notifies the control circuit 21.

Therefore, the vacuum pump 17 stops operating and evacuation is discontinued. Then, the control circuit 21 recognizes that the flying height of the head 2 has become the optimum state for recording/reproducing data, and that the device at position 1E (not shown) is ready for recording/reproducing data. Sends a ready signal to notify. Therefore, a command is given from the host device to the control circuit 21 to position the head 2 on the target cylinder for recording/reproducing data.

The control circuit 21 instructs the servo circuit I9 the distance to the target cylinder and sends a seek command. Therefore, the servo circuit 19 supplies current to the motor 8 based on the servo information read by the servo head 10 to move the carriage 9 and position the head 2 on the track of the target cylinder.

When the head 2 is positioned on the target track, the control circuit 21 controls the write/continuation circuit 13 to write data to be sent by the host device, or to send data to be read by the head 2 to the host device. let

By the way, the air pressure inside the closed container 3 gradually increases over time due to leakage.

Therefore, since the flying height of the head 2 gradually increases as the air pressure inside the sealed container 3 increases, the level of data read by the head 2 decreases, and the level of data sent out by the amplifier circuit 14 becomes level (2). also decreases.

When the comparison circuit 15 becomes V2≧Vo, the switch circuit 16
The switch circuit 16 causes the vacuum pump 17 to supply current from the power source to evacuate the airtight container 3.

And ■. When ≧■1, the comparator circuit 15 sends a signal to the switch circuit 16, and the switch circuit 16 cuts off the current supplied to the vacuum pump 17.

Even if the switch circuit 16 issues a notification of current cutoff, the control circuit 21 ignores the notification after the first notification after the power is turned on.

FIG. 3 is a diagram illustrating the relationship between the slider flying height and the atmospheric pressure.

When the recording medium 1 rotates in the direction of arrow A, the slider 22 shown in FIG. 3(a) tilts and floats as shown. As shown in FIG. 3(b), the height of the slider 22 indicated by H and the height indicated by H2 are approximately 0.48 μm at 1 atmosphere, with the horizontal axis representing atmospheric pressure and the vertical axis representing the flying height. H2 floats by about 0.18 μm. Also, at 2 atmospheres H
, hardly changes, and H2 floats by about 0.2 μm.

At 0.1 atmosphere, Hl is a floating amount of about 0.15 μm, and H2 is a floating amount of about 0.12 μm.

Since the flying height of the slider 22 rapidly decreases below 0.1 atmosphere, in this embodiment, the air pressure inside the sealed container 3 is at least 0.
．． Control the pressure to 1 atm.

FIG. 4 is a diagram illustrating the relationship between the rotational speed of the recording medium and the flying height of the head.

Figure 4 shows the head floating 0.25 μm at atmospheric pressure (
(used in this example), the spring pressure of the head spring was increased, and the width of the slider surface was decreased to 0.18
This shows the case where the recording medium l is rotated using a device that levitates by μm (the conventionally used one), and when the recording medium l is raised from O rotation by 3600 rotations/rotation amount, 0.2
A head flying 5 μm has a rotation speed of 300 rotations/
It starts to float in minutes, and rapidly rises to reach 0.25 μm.

Therefore, for example, assuming a predetermined rotation speed of 1000 rotations/rotor, the vacuum pump 17 starts evacuation at this point, as described above. Then, as the air pressure inside the sealed container 3 decreases, the flying height of the head 2 begins to decrease, and the airtight container 3
When the atmospheric pressure within the space becomes approximately 0.1 atm and the recording medium 1 reaches the specified rotation speed of 3600 rpm, the flying height is 0.18
It is μm.

In addition, the head that flies by 0.18 μm is 1 as shown in ■.
It starts at 000 revolutions/on the rotor and levitates by 0.18 μm.

The head shown in ■ and the head shown in ■ have AE (A
Coustic f! +*1ssion) element, i.e.
When an element that converts the vibration of the head into an electrical signal is installed and the recording medium is rotated, the head shown in
The maximum value of the output of the E element is 20 mVras, and the maximum value of the output of the AE element is 6 mVras until the head (■) flies up.
00 mVrn+s.

Also, when the flying height of the head 2 is lowered and it comes into contact with the protrusion of the recording medium l which is rotating at 3600 rotations/rotation,
The maximum output of the AE element of the head is 150 mVrm.
s, and the maximum value of the output of the AE element of the head of ■ is 10
00+iVrms.

As mentioned above, compared to the conventional head (2), the head (2) of this embodiment has a shorter sliding time and less pressure before it floats, and the rotation of the recording medium decreases and the head makes contact again. This shows that the impact of time is also small.

In this embodiment, the exhaust valve of the vacuum pump 17 is opened when the power is turned on. However, the vacuum pump 17 is equipped with a pressurizing function, and the airtight container 3 is opened before the spindle motor 11 is rotated. Of course, the internal pressure may be increased to above atmospheric pressure.

Further, in the above embodiment, the atmospheric pressure is changed based on the level of the read signal from the magnetic disk, but the present invention is not limited to this, and the atmospheric pressure inside the casing is detected. A sensor may be provided and the atmospheric pressure may be controlled according to the sensor output.

Alternatively, after a predetermined time has elapsed after the power is turned on, it is assumed that the spindle motor has reached a predetermined rotation speed, and the air pressure may be reduced.

〔Effect of the invention〕

As explained above, the present invention reduces the air pressure inside the sealed container, so that even if a high-flying head with low head spring pressure and a large slider width is used, the flying height that requires this head can be improved. Since the amount of data can be set to a certain amount, it is possible to normally record/reproduce data to/from a recording medium. Therefore, it is possible to reduce energy consumption due to the pressure drop during sliding between the head and the recording medium, and it is therefore possible to avoid the occurrence of a crash.

In addition, since the pressure when the head is in contact with the recording medium is reduced and the occurrence of adhesion between the recording medium and the head is prevented, there is no need to add extra functions such as shaking the head when starting the spindle motor. .

[Brief explanation of drawings]

Fig. 1 is a diagram explaining the present invention in detail, Fig. 2 is a block diagram of a circuit showing an embodiment of the invention, Fig. 3 is a diagram explaining the relationship between slider flying height and atmospheric pressure, Fig. 4 FIG. 2 is a diagram illustrating the relationship between the rotational speed of a recording medium and the flying height of a head. In the figure, ■ is a recording medium, 2 is a head, 3 is a closed container, 5 is an air pressure control means, 6 is a control means, 7 is a servo means, 8 is a motor, 9 is a carriage, 10 is a servo head, and 11 is a spindle motor , 12 is a helad spring, 13 is a write/continue output circuit, 1
4 is an amplifier circuit, 15 is a comparison circuit, 16 is a switch circuit, 17 is a vacuum pump, 18 is a filter, 1
9 is a servo circuit, 20 is a drive circuit, 21 is a control circuit, and 22 is a slider. □A ((1) <b) Relationship between the amount of floating soil and atmospheric pressure

Claims (1)

[Claims] 1) In an apparatus in which a recording medium (1) and a head (2) that floats above the surface of the recording medium due to wind pressure accompanying the movement of the recording medium (1) are sealed, the recording medium ( 1) A head floating control method comprising controlling the flying height of the head (2) by adjusting the air pressure in a closed container (3) that seals the head (2). 2) The recording medium (1) and the head (2) which floats above the surface of the recording medium due to the wind pressure accompanying the rotation of the recording medium (1) are sealed, and the floating head (2) is used to record the An apparatus for recording/reproducing data on a recording medium (1), comprising an air pressure control means (5) for controlling the air pressure in an airtight container (3) that seals the recording medium (1) and the head (2). established,
Rotation of the recording medium (1) is started with the pressure inside the airtight container (3) being equal to or higher than atmospheric pressure, and the recording medium (1) is rotated.
) reaches a predetermined rotational speed, the air pressure inside the closed container (3) is reduced.