JPH05128757A - Magnetic disk recording and reproducing device - Google Patents

Abstract

PURPOSE:To easily perform the off-track correction only by changing the voltage impressed on a piezoelectric ceramics. CONSTITUTION:On the upper surface of a cover 3, a deformable fixed part 12 formed with a groove at the periphery of a part to fix a turning shaft 7 and supported by two supporting parts is formed. A pair of piezoelectric ceramics 15 and 16 is fitted by plates 17 and 18 at the position facing mutually holding the fixed part 12 between them. The tip part of these piezoelectric ceramics 15 and 16 is engaged to the fixed part 12, and flexible printing cables(EPC) 19 and 20 are connected to the piezoelectric ceramics 15 and 16.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic disk recording / reproducing apparatus, and more particularly to an apparatus for performing off-track correction using piezoelectric ceramics.

[0002]

2. Description of the Related Art In a magnetic disk recording / reproducing apparatus such as a hard disk apparatus, a head arm having a head is swingably arranged on a rotary shaft fixed between a base and a cover. A coil motor or the like is used for rocking. In such a recording / reproducing apparatus, when the base and the cover have different thermal expansion coefficients, the head arm is tilted and the head is displaced,
Recording / reproducing cannot be performed correctly on the magnetic disk.

Therefore, for example, as described in Japanese Utility Model Laid-Open No. 1-146363, a spacer formed of a material having a different coefficient of linear thermal expansion is inserted into the joint between the rotary shaft of the head arm and the housing, or As described in JP-A-2-64975, a head arm is provided with a temperature sensor and a heating member, and the heating member is heated according to the detection result of the temperature sensor to reduce off-track. There is something.

[0004]

However, when the spacers made of materials having different linear thermal expansion coefficients are used as in the former case, a positional deviation occurs when the magnetic disk recording / reproducing apparatus is deformed differently, In order to deal with such a situation, it is necessary to use spacers having different linear thermal expansion coefficients for each device. When the open loop control is performed by providing a temperature sensor and a heating member like the latter, there is a difference in thermal expansion amount due to variations in individual parts, and when using an in-line type head, not in the off-track direction. It cannot be dealt with because it extends in the time axis direction.

[0005]

In order to solve the above problems, the present invention provides piezoelectric ceramics on at least one of a base, a cover and a head arm.

[0006]

The head can read the position signal on the magnetic disk and change the voltage of the piezoelectric ceramics attached to the base or the cover according to the read result to tilt the rotary shaft of the head arm. The head arm can be bent by changing the voltage of the piezoelectric ceramic attached to the.

[0007]

Embodiments of the present invention will be described below with reference to the accompanying drawings. Here, FIG. 1 is an external perspective view of a magnetic disk recording / reproducing apparatus according to the first embodiment of the present invention, FIG. 2 is a perspective view of the apparatus with a cover removed, and FIG. 3 is an exploded view of a cover portion of the apparatus. FIG. 4 is a partially cutaway plan view of the same apparatus, FIG. 5 is a cross-sectional view of essential parts of the same apparatus, FIG. 6 is a graph showing an example of off-track measurement results of the same apparatus, and FIGS. FIG. 12 is a cross-sectional view of the main parts of the magnetic disk recording / reproducing apparatus according to the second to sixth embodiments, and FIG. 12 is an external perspective view of the magnetic disk recording / reproducing apparatus according to the seventh embodiment of the present invention. 13 is a partially cutaway perspective view of a magnetic disk recording / reproducing apparatus according to the invention of claim 2, FIG. 14 is a perspective view of a main part of the apparatus, FIG. 15 is a partially cutaway plan view of the apparatus, and FIG. 16 is the present invention. FIG. 7 is a partially cutaway plan view of another example of FIG.

The magnetic disk recording / reproducing apparatus 1 has a base 2
A plurality of magnetic disks 4 rotating about a rotation shaft 4a are stacked in a housing formed by a cover 3 and a cover 3 at predetermined intervals, and a magnetic head 5 for performing recording and reproduction on each magnetic disk 4 is provided. A plurality of head arms 6 are swingably arranged around a rotary shaft 7, and a voice coil motor 8 for swinging the head arms 6 is provided.

On the upper surface of the cover 3, a fixing portion 12 which is supported by two supporting portions 11 by forming a groove around the portion for fixing the rotating shaft 7 and which can be easily deformed in the arrow direction shown in FIG. The elastic member 13 is mounted in the groove around the fixing portion 12. Then, a pair of piezoelectric ceramics 15 and 16 are attached by plates 17 and 18 in grooves 14 and 14 formed on the upper surface of the cover 3 so as to face each other with the fixed portion 12 interposed therebetween, and the tip portions of these piezoelectric ceramics 15 and 16 are attached. Flexible print cables (FPC) 19 and 20 are connected to the piezoelectric ceramics 15 and 16 by engaging with the notches 12a and 12b formed in the fixed portion 12.

As described above, since the fixing portion 12 for fixing the rotating shaft 7 of the cover 3 is formed to be deformable and the piezoelectric ceramics 15 and 16 for deforming the fixing portion 12 are provided, the base 2 and the cover 3 are provided. Distorted and rotating shaft 4a of magnetic disk 4
When the rotary shaft 7 is tilted with respect to the head No. 1, as shown in FIG. When there are 10 heads 0 to 9 and the lower head is off-track to the outer circumference side and the upper head is off-track to the inner circumference side as shown by the circles in the figure (head No. The head of No. 5 is used as a servo surface.), And a voltage is applied to the piezoelectric ceramics 15 to rotate the rotary shaft 7
Can be tilted, and the off-track amount of each head can be reduced as indicated by the ● mark in the figure. In this case, the same effect can be achieved by applying a positive voltage to the piezoelectric ceramic 15 and a negative voltage to the piezoelectric ceramic 16.

The piezoelectric ceramics 15 and 16 do not have to be positioned on the same straight line. Further, as shown in FIG. 4, the center of rotation of the head arm 6 is O, and the magnetic disk 4 is
R1 is the outermost circumference of the data area and R is the innermost circumference of the data area
2. H1 is the intersection of the swing line of the head 5 and the outermost circumference R1 of the data area, and the swing line of the head 5 is the innermost circumference R2 of the data area.
When the intersection with and is H2, the O point and the piezoelectric ceramic 1
The straight line connecting the longitudinal center lines of 5 and 16 is between the perpendicular line OH1 ′ passing through the O point of the straight line connecting the O point and the H1 point and the perpendicular line OH2 ′ passing through the O point of the straight line connecting the O point and the H2 point. However, it is not necessary to be between OH1 and OH2.

In each of the embodiments shown in FIGS. 7 to 11, the mounting positions of the piezoelectric ceramics 15 and 16 are different from those in the above embodiment. In the embodiment shown in FIG. In the example, the cover 3 is hollowed out and attached,
In the embodiment of FIG. 9, it is attached to the outside of the base 2, in the embodiment of FIG. 10 it is attached to the inside of the base 2, and in the embodiment of FIG. 11, the base 2 is hollowed out and attached.

Further, in the embodiment of FIG. 12, only one piezoelectric ceramic 15 is used. In this case, a predetermined voltage V is applied in the initial state in advance, and V + α depending on the correction direction. Alternatively, a voltage of V-α may be applied. Although the piezoelectric ceramics are provided on only one of the base and the cover in each of the above embodiments, they may be provided on both.

Next, the magnetic disk recording / reproducing apparatus 21 shown in FIG. 13 has the same structure as the above-mentioned magnetic disk recording / reproducing apparatus 1, but in this apparatus, two piezoelectric ceramics 21, 22 are provided in the head arm 6. It is attached. As shown in FIG. 15, these piezoelectric ceramics 21 and 22 have a center point O of rotation of the head arm 6 and a magnetic head gap HG.
It is attached in a contradictory form at a position away from the straight line connecting with.

Here, if the track signal is off-tracked to the outer peripheral side by the position signal on the magnetic disk, the voltage is applied to the piezoelectric ceramics 24, so that the piezoelectric ceramics 2
4 extends in the longitudinal direction, and the magnetic head 5 shifts toward the inner peripheral side. In this case, by applying a positive voltage to the piezoelectric ceramics 24 and a negative voltage to the piezoelectric ceramics 23, or by applying a predetermined voltage V in the initial state in advance, a voltage of V + α is applied to the piezoelectric ceramics 24. The same effect can be achieved by applying a voltage V-α to the piezoelectric ceramics 23. Also,
When the in-track is performed on the inner peripheral side, a voltage reverse to the above may be applied.

In the embodiment shown in FIG. 16, only one piezoelectric ceramic 24 is attached at a position apart from the straight line connecting the rotation center point O of the head arm 6 and the magnetic head gap HG. In this case, by applying a predetermined voltage V in the initial state in advance and applying a voltage of V + α when the off-track is on the outer peripheral side, the piezoelectric ceramics 24 extend in the longitudinal direction and the magnetic head 5 moves to the inner peripheral side. It shifts to the side. When the off-track is on the inner circumference side, V-α
The voltage of 1 may be applied.

FIG. 17 and FIG. 18 show block diagrams of an example of off-track correction control according to the present invention. Figure 17
An example of an off-track correction control block diagram when piezoelectric ceramics is attached to a base or a cover is shown, and a tracking servo head (HEAD) is shown.
The off-track amount and the off-track direction of the disk lowermost head and the uppermost head (HEAD0 and HEAD9) for 5) are measured, and the applied voltage of the piezoelectric ceramics is controlled in the direction of decreasing the off-track amount. FIG. 18 shows an example of an off-track correction control block diagram when the piezoelectric ceramics are attached to the head arm. The off-track amount and off-track direction of the heads on each disk other than HEAD5 for the tracking servo head (HEAD5) are shown. Is measured
The applied voltage to the piezoelectric ceramics of each arm is controlled so as to reduce the off-track amount. FIG. 18 shows H
Although nine heads other than EAD5 are independently controlled for control, one piezoelectric ceramic may control a plurality of heads depending on the required off-track accuracy. Needless to say, it may not be necessary to control the head near HEAD5, which has a small amount of off-track.

[0018]

As described above, according to the present invention,
Since the piezoelectric ceramics are provided on at least one of the base, the cover, and the head arm, off-track can be corrected by changing the voltage applied to the piezoelectric ceramics. Differences can be easily accommodated.

[Brief description of drawings]

FIG. 1 is an external perspective view of a magnetic disk recording / reproducing apparatus according to a first embodiment of the present invention.

FIG. 2 is a perspective view of the same device with a cover removed.

FIG. 3 is an exploded perspective view of a cover portion of the device.

FIG. 4 is a partially cutaway plan view of the device.

FIG. 5 is a sectional view of the main part of the device.

FIG. 6 is a diagram of an example of off-track measurement results of the device.

FIG. 7 is a cross-sectional view of essential parts of a magnetic disk recording / reproducing apparatus according to a second embodiment of the present invention.

FIG. 8 is a cross-sectional view of essential parts of a magnetic disk recording / reproducing apparatus according to a third embodiment of the present invention.

FIG. 9 is a cross-sectional view of essential parts of a magnetic disk recording / reproducing apparatus according to a fourth embodiment of the present invention.

FIG. 10 is a cross-sectional view of essential parts of a magnetic disk recording / reproducing apparatus according to a fifth embodiment of the present invention.

FIG. 11 is a cross-sectional view of essential parts of a magnetic disk recording / reproducing apparatus according to a sixth embodiment of the present invention.

FIG. 12 is an external perspective view of a magnetic disk recording / reproducing apparatus according to a seventh embodiment of the present invention.

FIG. 13 is a partially cutaway perspective view of a magnetic disk recording / reproducing apparatus according to a second aspect of the invention.

FIG. 14 is a perspective view of the main part of the device.

FIG. 15 is a partially cutaway plan view of the same device.

FIG. 16 is a partially cutaway plan view of another embodiment of the present invention.

FIG. 17 is an off-track correction control block diagram when the piezoelectric ceramics of the present invention is attached to a base or a cover.

FIG. 18 is an off-track correction control block diagram when the piezoelectric ceramics is attached to the head arm of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Magnetic disk recording / reproducing apparatus, 2 ... Base, 3 ... Cover, 4 ... Magnetic disk, 5 ... Magnetic head, 6 ... Head arm, 7 ... Rotating shaft, 8 ... Voice coil motor, 11 ... Support part, 12 ... Fixed parts, 15, 16, 23, 24 ... Piezoelectric ceramics, 17, 18 ... Plates.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Eiji Ishiguro 3-12 Moriya-cho, Kanagawa-ku, Yokohama, Kanagawa Japan Victor Company of Japan, Ltd. (72) Inventor Satoshi Yoshida 3--12 Moriya-cho, Kanagawa-ku, Yokohama Address inside Victor Company of Japan, Ltd.

Claims (2)

[Claims] 1. A magnetic disk recording / reproducing apparatus in which a head for recording / reproducing on / from a magnetic disk is attached to a head arm, and the head arm is swingably mounted on a rotary shaft fixed between a base and a cover. A fixing portion for fixing the rotating shaft of at least one of the base and the cover is formed to be deformable, and the fixing portion is deformed to attach the piezoelectric ceramics for tilting the head arm in the off-track direction to the base or the cover. Characteristic magnetic disk recording / reproducing device. 2. A magnetic disk recording / reproducing apparatus in which a head for recording / reproducing on / from a magnetic disk is attached to a head arm, and the head arm is swingably mounted on a rotary shaft fixed between a base and a cover, A magnetic disk recording / reproducing apparatus, wherein piezoelectric ceramics for tilting the head arm in an off-track direction are attached to the head arm.