JPH0581796A - Magnetic disk device - Google Patents

Abstract

(57) [Summary] [Object] To provide a magnetic disk device in which track deviation does not occur between writing and reading even when a magnetic head having a writing element and a reading element individually configured is driven by a rotary actuator. With the goal. [Structure] In a magnetic disk device in which a magnetic head 1 in which a writing element 2 and a reading element 3 are arranged substantially parallel to each other is rotatively moved in a radial direction of a magnetic disk by a rotary actuator 5 to perform a seek, On the other hand, a magnetic disk device provided with an auxiliary actuator 12 that holds the relative angle of the write element 2 and the read element 3 with respect to the track direction constant by rotating the magnetic head 1 according to the track position.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic disk device, and more particularly to a magnetic disk device that seeks by driving a magnetic head having a write element and a read element by a rotary actuator.

[0002]

2. Description of the Related Art In a magnetic disk device such as a hard disk device or a floppy disk device, the same magnetic head is conventionally used for writing and reading information. On the other hand, a high-sensitivity read-only head including a so-called magnetoresistive magnetic head using a magnetoresistive effect element (MR element) has begun to be noticed in a magnetic disk device. When such a read-only head is used, it goes without saying that a separate magnetic head for writing must be prepared.

FIG. 4 is an example of such a magnetic head, and shows an example of a magnetic head in which a write element and a read element are integrated in a thin film structure. This is a head of a system called piggyback, and an MR element 33 as a reading element is provided on a head slider 31 with an insulating layer 32 interposed therebetween.
And a lead conductor 34 connected thereto, and a lower core 36 and an upper core 37 are laminated on the lead conductor 34 via an insulating layer 35.
A write element having a write gap 38 and a coil conductor 39 provided therebetween is laminated to form a structure. This magnetic head is arranged so as to face the magnetic disk 40 as shown in the figure.

On the other hand, as a magnetic head driving method in a magnetic disk device, recently, a rotary actuator method, which is small and capable of moving the magnetic head at high speed, has been widely adopted in place of the linear motor method. As shown in FIG. 5, the arm 42 having the magnetic head 41 attached to the tip thereof is rotated about a rotation shaft 43 as a fulcrum to move the magnetic head 41 in the radial direction between the inner and outer circumferences of the magnetic disk 40. This is a method of seeking. In this method, the relative angle between the track direction and the magnetic head 41 is not constant in each track. In other words, the azimuth angle of the magnetic head 41 (angle formed by the gap direction of the magnetic head 41 and the track width direction) is different in each track.
When the magnetic head 41 is a write / read head, even if the track direction and the relative magnetic head are different in each track, no particular problem occurs.

However, in the case where the magnetic head 41 is such that the write element and the read element as shown in FIG. 4 are separately formed and arranged in parallel on the same slider, if the relative angles of the tracks are different, As shown in FIG. 6, the trace positions of the write element 51 and the read element 52 that are stacked do not always become the same. FIG. 6 shows changes in the trace positions of the write element 51 and the read element 52 due to the difference in the relative angle between the track direction and the magnetic head. As shown in FIG. 6A, the relative angle between the track direction and the write element 51 and the read element 52 is 9
In the state of 0 ° (corresponding to the state of azimuth angle of 0 °), the write element 51 and the read element 52 trace the same position (position indicated by arrow 54) on the same track 53.

On the other hand, when the relative angle between the track direction and the write element 51 and the read element 52 deviates from 90 °, as shown in FIG. 6B, for example, as shown in FIG.
In the case where the write element 51 traces the position of the arrow 56 and the read element 52 traces the position of the arrow 57 slightly deviated to the inner circumferential side from the above state, the write element 51 traces the position of the arrow 56. As a result, a positional deviation occurs when tracing the track 55 between writing and reading (this is called a track deviation). As a result,
The read output from the read element 52 is reduced by the ratio of the track deviation to the track width. The decrease in the read output due to the track deviation becomes more remarkable as the track width is narrowed to increase the track density, which causes a problem such as an increase in error rate.

[0007]

As described above, conventionally, when a magnetic head in which a writing element and a reading element are individually configured is driven by a rotary actuator, track deviation occurs between writing and reading, and reading output is reduced. There was a problem to do.

The present invention has been made in view of the above points, and even when a magnetic head having a writing element and a reading element individually driven by a rotary actuator, a track deviation occurs between writing and reading. An object of the present invention is to provide a magnetic disk device that does not occur.

[0009]

In order to solve the above problems, the present invention provides a write element for writing information on a desired track on a magnetic disk and a read element for reading the written information substantially in parallel. In the magnetic disk device in which the arranged magnetic head is rotatively moved in the radial direction of the magnetic disk by the rotary actuator to perform seek, by rotating the magnetic head with respect to the rotary actuator according to the track position. An auxiliary actuator that keeps the relative angle of the write element and the read element with respect to the track direction constant is provided. The auxiliary actuator is composed of, for example, a piezoelectric element.

Further, in the present invention, in order to drive the auxiliary actuator, a memory for storing drive information for the auxiliary actuator corresponding to each track position is provided, and the drive information corresponding to the target track is read from this memory to assist the auxiliary actuator. Supply to the actuator.

Further, in the present invention, the rotary actuator is composed of a plurality of arms connected via the rotary shafts, and the auxiliary actuators are arranged in the vicinity of the respective rotary shafts, so that the angles formed by the arms on both sides of the rotary shaft are formed. May be variable.

[0012]

As described above, according to the present invention, in each track on the magnetic disk, the relative angle of the write element and the read element with respect to the track direction is kept constant by rotating the magnetic head with respect to the rotary actuator by the auxiliary actuator. Be done. As a result, the problem of track deviation during writing and reading is solved, and the reduction in read output due to the track position is eliminated.

[0013]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a diagram showing a configuration of a head drive device in a magnetic disk device according to an embodiment of the present invention.

In FIG. 1, a magnetic head 1 has a writing element 2 and a reading element 3 arranged in parallel on a slider 4. For example, a piggyback as shown in FIG.
It is a method head. The rotary actuator 5 rotationally moves the magnetic head 1 in a radial direction of a magnetic disk (not shown). The rotary actuator 5 includes a first arm 7 connected to a gimbal 6 that supports the magnetic head 1 and a rotary shaft 8 attached to the arm 7. The second arm 9 is connected by. The arm 9 is fixed to a base plate (not shown) of the magnetic disk device by a rotary shaft 10. Also, the second arm 9
A coil 11 of a VCM (voice coil motor) which is a drive source of the rotary actuator 5 is attached to the base end of the.

On the other hand, the auxiliary actuator 12 rotates the magnetic head 1 with respect to the rotary actuator 5 in accordance with the track position in order to keep the relative angle of the write element 2 and the read element 3 with respect to the track direction constant. Yes, it is configured as follows: Protrusions 13a, 1 are formed on the sides of the first arm 7 and the second arm 9.
3b is provided, and the support bases 15a, 15 are provided on these protrusions 13a, 13b via the rotary shafts 14a, 14b.
The piezoelectric element 16 is held between b. Piezoelectric element 1
In this example, a laminated piezoelectric element 6 is used.

The piezoelectric element expands and contracts according to the applied voltage, and generally expands when the applied voltage increases and contracts when the applied voltage decreases.
Therefore, by controlling the drive voltage applied to the piezoelectric element 16, the angle formed by the two arms 7 and 9 of the rotary actuator 5 can be changed as the piezoelectric element 16 expands and contracts. That is, the magnetic head 1 rotates with respect to the rotary actuator 5.

A driving voltage is applied to the piezoelectric element 16 by an auxiliary actuator driver 17. The CPU 18 is for performing overall control of the magnetic disk device, and a memory (ROM) is controlled by the CPU 18.
Digital drive information for the auxiliary actuator 12 is read from 19, converted into an analog value by the D / A converter 20, and then supplied to the driver 17.

Next, the operation when the head drive device of FIG. 1 is applied to an actual magnetic disk device such as a hard disk device will be described. FIG. 2 shows the behavior of the rotary actuator 5 and the auxiliary actuator 12 in each track on the magnetic disk.

Now, in FIG. 2, when the magnetic head 1 is on-track to the track 21B, the arms 7 and 9 are located on a straight line. From this state, when the magnetic head 1 is moved to the inner circumference side of the disk to be on-track on the track 21A, the drive voltage applied to the piezoelectric element 16 is lowered and the arm 7 is rotated clockwise. As a result, the arm 7 is placed on the tangent line of the track 21A. On the contrary, when the magnetic head 1 is moved to the outer peripheral side of the disk to be on-track on the track 21C, the drive voltage applied to the piezoelectric element 6 is increased and the arm 7 is rotated counterclockwise to track the arm 7. Two
Position on the tangent line of 1C.

As described above, the arm 7 is provided on any track.
By making the tangent line of the track parallel to the tangent line of the track, the relative angle between the track and the write element 2 or read element 3 of the magnetic head 1 can be kept constant (approximately 90 °). To this end, the memory 19 shown in FIG. 1 previously obtains information on the drive voltage (drive information) to be applied to the piezoelectric element 16 in each track, and stores it as a digital value.
Each time the seek operation is performed, the CPU 18 knows the target track, and based on this, the drive information corresponding to the target track may be read from the memory 19. And the memory 19
The drive information read from the device is converted into an analog value by the D / A converter 20, and the piezoelectric element 16 is transferred via the driver 17.
The above operation is performed by applying a drive voltage to the.

In the above embodiment, the rotary actuator arm is divided into two parts, but as shown in FIG. 3, the arm is divided into three or more parts like 7 and 9a and 9b to rotate. Auxiliary actuators 12a, 1 similar to those described above are connected by the shafts 8a, 8b, and between the respective connecting parts, that is, between the arms on both sides of the rotary shafts 8a, 8b.
2b may be attached to change the angle formed by both arms. When a plurality of auxiliary actuators 12a and 12b are used as described above, the stroke of the piezoelectric element in each auxiliary actuator may be short, the realization thereof is easy, and the variable range of the driving voltage of the piezoelectric element may be small. There are advantages.

The piezoelectric element of the auxiliary actuator is not limited to the laminated piezoelectric element, and a bimorph type piezoelectric element may be used. A large stroke can be easily obtained by using the bimorph type piezoelectric element.

Furthermore, the auxiliary actuator does not rotate the arm of the rotary actuator, but may be incorporated in the magnetic head assembly itself to rotate only the head chip.

[0024]

According to the present invention, the relative angle of the write element and the read element with respect to the track direction can be kept constant in all tracks on the magnetic disk while using the rotary actuator. Therefore, a large read output can be obtained on any track without causing track deviations during writing and reading.
Even if the track is narrowed to increase the density of the disc, the error rate at the time of reading can be suppressed.

[Brief description of drawings]

FIG. 1 is a configuration diagram of a head drive device in a magnetic disk device according to an embodiment of the present invention.

FIG. 2 is a diagram showing the behavior of the actuator in each track for explaining the operation of the embodiment.

FIG. 3 is a diagram showing a main part of another embodiment of the present invention.

FIG. 4 is a sectional view of a magnetic head in which a writing element and a reading element are integrated.

FIG. 5 is an explanatory diagram of a rotary actuator in the magnetic disk device.

FIG. 6 is a diagram for explaining a track shift at the time of writing and at the time of reading due to a change in a relative angle between a track direction and a magnetic head in a conventional technique.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Magnetic head 2 ... Writing element 3 ... Reading element 4 ... Slider 5 ... Rotary actuator 6 ... Gimbal 7 ... Arm 8 ... Rotating shaft 9 ... Arm 10 ... Rotating shaft 11 ... VCM coil 12 ... Auxiliary actuator 16 ... Piezoelectric element 19 …memory

Claims (3)

[Claims] 1. A magnetic head in which a write element for writing information on a desired track on a magnetic disk and a read element for reading the written information are arranged substantially parallel to each other; A rotary actuator that rotates in a radial direction, and an auxiliary device that keeps a relative angle of the write element and the read element to the track direction constant by rotating the magnetic head according to the track position with respect to the rotary actuator. A magnetic disk device comprising an actuator. 2. Storage means for storing drive information for the auxiliary actuator corresponding to each track position, and means for reading drive information corresponding to the desired track from the storage means and supplying the drive information to the auxiliary actuator. The magnetic disk device according to claim 1, further comprising: 3. The rotary actuator has a plurality of arms connected via rotary shafts, and the auxiliary actuators are arranged in the vicinity of the respective rotary shafts, and an angle formed by the arms on both sides of the rotary shaft is formed. 3. The magnetic disk device according to claim 1, wherein the magnetic disk device is variable.