JPH0991908A - Disk device and head device - Google Patents

Abstract

(57) [Summary] [Structure] A part of the head arm 6 is provided with a piezoelectric material member 25,
26, by controlling the polarity / absolute value of the voltage applied to the electrodes 27, 28, 29, 30 and controlling the deformation direction and the deformation amount of the head arm 6 due to expansion and contraction of the member,
The position of the head 7 can be finely adjusted. [Effect] By enabling the fine adjustment of the relative position between a plurality of heads, the variation in the expansion / contraction amount of the disk is corrected,
It is possible to simultaneously access the same sector on multiple disks by multiple heads.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a disk device such as a hard disk device using a disk as an information storage medium, and more particularly to a disk device using a plurality of disks and a plurality of heads, and a disk device of this type. The present invention relates to a head device for recording and reproducing information.

[0002]

2. Description of the Related Art A magnetic disk used as an information recording medium in a hard disk device expands and contracts in the radial direction due to thermal expansion. The degree of expansion / contraction varies depending on the material of the magnetic disk, but in a general magnetic disk made of aluminum, the expansion / contraction amount is not negligible.

In a hard disk device using a plurality of magnetic disks and a plurality of magnetic heads, there is considerable variation in temperature distribution due to a difference in distance from a heat source such as a motor. The amount of expansion and contraction due to expansion is not uniform.

However, in the conventional hard disk device, the head arm supporting each magnetic head is integrally fixed, and all the magnetic heads are moved integrally, and each magnetic head is moved individually. It is not possible. Therefore, if there is variation in the expansion / contraction amount of the magnetic disk, when the magnetic head corresponding to the magnetic disk is positioned at the target sector on one magnetic disk, the target sector and the magnetic head on the other magnetic disk are Will be displaced. As a result, there is a problem that a plurality of magnetic heads cannot simultaneously access the same sector of a plurality of magnetic disks.

[0005]

SUMMARY OF THE INVENTION It is an object of the present invention to solve the above-mentioned problems due to variations in the expansion / contraction amount of a disk in a disk device such as a hard disk device using a plurality of disks and a plurality of heads, and It is an object of the present invention to provide a disk device in which the same sector on a plurality of disks can be simultaneously accessed, and to provide an improved head device for realizing such a disk device.

[0006]

In order to achieve the above-mentioned object, the invention according to claim 1 has a plurality of discs as information recording media and a plurality of discs for recording and reproducing information on the plurality of discs. In a disk device having a head and a head driving means for integrally moving the plurality of heads relative to the plurality of disks, according to an individual control signal for each of the plurality of heads, It is characterized in that fine adjustment means for finely adjusting the relative position of the head is provided independently of the head drive means.

According to a second aspect of the present invention, there is provided a head device having a head for recording / reproducing information on / from a recording medium and a head arm for supporting the head,
At least a part of the head arm is made of a piezoelectric material member, and means for externally applying a voltage to the piezoelectric material member is provided.

[0008]

If the temperature distribution inside the disk device is not uniform, the amount of expansion and contraction of the disk will vary due to thermal expansion. If there is such variation in the amount of disk expansion / contraction,
When it is attempted to move a plurality of heads to target sectors on a plurality of disks by the head drive means, for some disks, the heads are correctly aligned to the target sectors, but other disks with different expansion and contraction amounts are used. With respect to, the position of the head and the target sector are displaced. Such positional deviation cannot be compensated by a head driving unit that integrally drives a plurality of heads.

In the disk device according to the first aspect of the present invention, the relative position between the heads is finely adjusted by the fine adjustment means so that the positional deviation due to the variation in the expansion / contraction amount of the disk as described above is caused. Can be corrected,
As a result, the head can be correctly aligned with the target sector for all the disks at the same time. Therefore, it is possible to simultaneously access the same sector of a plurality of disks.

The piezoelectric material has the property of expanding and contracting in the polarization direction when a voltage is applied from the outside. In the head device according to the second aspect of the present invention, by appropriately selecting the shape, position, and polarization direction of the piezoelectric material member forming the head arm, it is possible to achieve a desired overall shape of the head arm according to the applied voltage. Alternatively, a partial deformation can be caused to finely adjust the position of the head supported by the head arm.

When this head device is used as a head device of a disk device according to the first aspect of the present invention, for example, by controlling the applied voltage (control signal) to the piezoelectric material member of the head arm of each head device, The relative position between the heads can be finely adjusted to cancel the variation in the expansion / contraction amount of the disk.

[0012]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a schematic side view showing an embodiment of a hard disk device according to the present invention. The example shown in FIG.
It has one magnetic disk 1 (1a, 1b, 1c). These magnetic disks 1 are fixed to a rotating shaft 3 of a motor 2,
It is rotationally driven at high speed by the motor 2. The number of magnetic disks 1 may be two or four or more.

There are three magnetic head devices 5 for recording / reproducing information on / from each magnetic disk 1. Although the present embodiment is an example in which information is recorded / reproduced only on one side of the magnetic disk 1, it goes without saying that a configuration in which information is recorded / reproduced on both sides of the magnetic disk 1 is also possible.

Each magnetic head device 5 includes a head arm 6
This is a schematic structure in which the magnetic head 7 is fixed to the tip of (see FIGS. 2 and 3). The magnetic head 7 is, for example, disclosed in JP-A-63-1.
As described in Japanese Patent Publication No. 29515, it is a floating type that records and reproduces information while floating a minute amount from the surface of a magnetic disk by an air bearing.

The head arm 6 of each magnetic head device 5 is
The rear end is supported by a shaft 9 via a bearing 8 and is rotatable about the shaft 9 in a direction parallel to the surface of the magnetic disk 1. Therefore, each magnetic head device 5
The magnetic head 7 can move in a direction crossing a corresponding track on the magnetic disk 1. However, since the head arms 6 of all the magnetic head devices 5 rotate integrally, all the magnetic heads 7 move integrally.

As means for driving the head arm 6 of each magnetic head device 5, a coil 11 (see FIG. 2) is attached to the rear end of each head arm 6 and is arranged in a direction perpendicular to the surface of each coil 11. A magnetic field generator 12 (a block of a permanent magnet or the like) for generating a magnetic field is provided. By controlling the current flowing through the coil 11 of each magnetic head device 5, the angles of the head arms 6 of all the magnetic head devices 5, and hence the positions of the magnetic heads 7, can be changed simultaneously.

The basic structure of the apparatus described above is the same as that of the conventional hard disk apparatus. A structural feature different from the conventional one is the structure of the head arm 6 of each magnetic head device 5. This will be described below.

FIG. 2 is a schematic plan view showing an example of the magnetic head device 5. The shaft 9 and the bearing 8 are not shown as components of the magnetic head device 5, but are shown for clarity of correspondence with FIG.

The head arm 6 has a rear end portion 20 as a whole,
The magnetic head 7 has a structure in which three parts, that is, an intermediate portion 21 and a tip portion 22 are connected in series, and the magnetic head 7 is fixed to the tip of the tip portion 22. A circular hole for attaching to the bearing 8 is formed in the rear end portion 20 of the head arm 6, and a part of the circumferential portion of this circular hole is made of a piezoelectric material member 25, 2.
It is supposed to be 6. As the piezoelectric material, for example, titanate (PbTiO ₃ ) is used. Piezoelectric material member 2
Electrodes 27, 28, 29, 30 for applying a voltage from the outside are provided at both ends of 5, 26. This electrode 2
7 to 30 and the coil 11 are wired by an insulated wire or the like, but this wiring is omitted for simplification of the drawing.

The piezoelectric material members 25 and 26 are processed so that the polarization direction is the longitudinal direction. Electrodes 27, 29
When a voltage having a polarity in which the polarity is + and the electrodes 28 and 30 are − is applied, one piezoelectric material member 25 contracts and the other piezoelectric material member 26 expands, so that the piezoelectric material member 25 of the head arm 6 is expanded. , 26 is clockwise 32 at the tip side
Therefore, the magnetic head 7 moves upward in FIG. When the polarity of the applied voltage is reversed, the piezoelectric material member 25 on one side expands and the piezoelectric material member 26 on the other side contracts. Therefore, the deformation direction of the head arm 6 is reversed, and the magnetic head 7 moves downward in FIG. Move in the direction. The amount of deformation of the head arm 6, and hence the amount of movement of the magnetic head 7, is determined by the absolute value of the voltage applied to the piezoelectric material members 25 and 26.

Therefore, by controlling the voltage applied to the piezoelectric material members 25 and 26 of the head arm 6 of each magnetic head device 5, the magnetic heads 7 of each magnetic head device 5 are individually moved in the radial direction of the magnetic disk. It can be moved slightly. That is, the relative position between the magnetic heads 7 of the plurality of magnetic head devices 5 can be finely adjusted.

FIG. 3 is a partially enlarged view for explaining a modified example of the head arm 6. In the modification shown here, a part of the tip end portion 22 of the head arm 6 is provided with a pair of piezoelectric material members 3.
2, 34, and electrodes 36, 37, 38, 39 for applying a voltage are provided at both ends of each. The piezoelectric material members 33 and 34 are processed so as to have a polarization direction in the longitudinal direction. Other than this, the head arm 6 shown in FIG.
It has the same structure as.

According to this modification, the expansion and contraction of the piezoelectric material members 33 and 34 constituting the tip end portion of the head arm 6 and the expansion and contraction of the piezoelectric material members 25 and 26 (FIG. 2) constituting the rear end portion thereof. With the combination, the position of the magnetic head 7 can be finely adjusted in any direction such as up, down, left and right in FIG.

FIG. 4 is a simplified block diagram of the hard disk device of this embodiment. In FIG. 4, a control circuit section 41 is a section that controls the internal operation of the hard disk device and the exchange of signals with the outside. Under the control of the control circuit unit 41, the read / write circuit unit 42 reproduces the read information by the magnetic head 7 of each magnetic head device 5, passes the information to the control circuit unit 41, and the control circuit unit 41 This is a portion for supplying a recording signal of given write information to each magnetic head 7. The seek control circuit section 43 is a section that drives the coil 11 of each magnetic head device 5 under the control of the control circuit section 41 to seek each magnetic head 7 to a target track. The motor drive circuit section 44 is a section that drives the motor 2 under the control of the control circuit section 41. The fine adjustment circuit unit 45 is a unit for adjusting the polarity and absolute value of the applied voltage to the piezoelectric members 27, 26 (and 33, 34) of each magnetic head device 5 under the control of the control circuit unit 41.

FIG. 5 shows a control flow for fine adjustment of the relative position between the magnetic heads for correcting the positional deviation between the magnetic disks 1 due to thermal expansion or the like. This control operation is performed, for example, when the hard disk device is started up, at predetermined times, or when arbitrarily instructed.

The control circuit section 41 performs control for reading the sector servo of each magnetic disk 1, and reads the sector servo information of each magnetic disk 1 via the read / write circuit section 42 (step 51). Then, the control circuit unit 41 determines whether the sector servo of one magnetic disk (for example, 1b) serving as a reference is the same as the sector servo of all other magnetic disks (for example, 1a and 1c) (step 52). If the sector servos of all the magnetic disks 1 match, the magnetic heads 7 of all the magnetic disks 1 are located in the same sector and there is no need to perform relative position fine adjustment between the magnetic heads 7, so the control ends.

If there is at least one magnetic disk whose sector servo does not match the reference magnetic disk, there is a relative positional deviation between the magnetic disks, and therefore the control circuit unit 41 is based on the read sector servo information of each magnetic disk. Then, with respect to the magnetic head corresponding to the non-coincident magnetic disk, the fine adjustment movement direction and the movement amount necessary to correct the positional deviation are calculated and the fine adjustment circuit unit 45 is instructed (step 53). The fine adjustment circuit unit 45 adjusts the polarity and absolute value of the applied voltage to the piezoelectric members (27, 26, 33, 34) of the corresponding magnetic head device 5 according to the moving direction and the moving amount (step 54).

After finely adjusting the relative position between the magnetic heads in this manner, the control circuit unit 41 again performs reading of the sector servo (step 51) and determination of coincidence of the sector servo (step 52). If the fine adjustment of the magnetic heads of all the magnetic disks that did not match the previous time is successful, the sector servos of all the magnetic disks match and the control operation ends. However, if there is still a magnetic disk that does not match, the necessary fine adjustment movement direction and movement amount are calculated for the magnetic head 7 of the magnetic disk (step 53), and the fine adjustment circuit unit 45 causes the piezoelectric member to move. Is adjusted (step 54), after which step 51 and step 52 are repeated.

By performing the control operation for finely adjusting the relative position between the magnetic heads once or a plurality of times, if the relative positional deviation between the magnetic disks due to thermal expansion or the like is corrected, the total magnetic field is reduced. The same sector of the disk can be accessed at the same time.

Although the hard disk device described above has a structure in which a plurality of magnetic heads are rotated, it is a matter of course that the plurality of magnetic heads may be linearly moved in the radial direction of the magnetic disk. Further, it is obvious that the present invention can be applied to a disk device other than the hard disk device and its head device. Further, the detailed structure of the head arm is not limited to that of the above-mentioned embodiment, but can be changed appropriately.

[0032]

As described above in detail, according to the present invention, in a disk device such as a hard disk device in which variations in expansion and contraction of a plurality of disks cannot be ignored,
By finely adjusting the relative position between the plurality of heads and correcting the variation in expansion and contraction of the disks, it becomes possible for the plurality of heads to simultaneously access the same sector on the plurality of disks. Further, it is possible to obtain an effect that it is possible to correct the variation in expansion and contraction between the disks and to provide a head device having a relatively simple structure.

[Brief description of drawings]

FIG. 1 is a schematic side view of an embodiment of a hard disk device according to the present invention.

FIG. 2 is a schematic plan view showing an example of a magnetic head device according to the present invention.

FIG. 3 is an enlarged partial plan view showing a modified example of the head arm of the magnetic head device according to the present invention.

FIG. 4 is a schematic block diagram showing a configuration of a control system of an embodiment of a hard disk device according to the present invention.

FIG. 5 is a flowchart showing a control flow of fine adjustment of relative positions between magnetic heads in an embodiment of a hard disk device according to the present invention.

[Explanation of symbols]

 1 (1a, 1b, 1c) Magnetic disk 2 Motor 3 Rotating shaft 5 Magnetic head device 6 Head arm 7 Magnetic head 8 Bearing 9 Axis 11 Coil 12 Magnetic field generating device 25, 26 Piezoelectric material member 27, 28, 29, 30 Electrode 33, 34 Piezoelectric material member 36, 37, 38, 39 Electrode 41 Control circuit part 42 Read / write circuit part 43 Seek control circuit part 44 Motor drive circuit part 45 Fine adjustment circuit part

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Shoji Tateshita 1 Horiyamashita, Hinoyama, Hadano, Kanagawa Pref., Inside of Hitachi Computer Electronics Co., Ltd. Office system division

Claims (2)

[Claims] 1. A plurality of disks as information recording media, a plurality of heads for recording / reproducing information on / from the plurality of disks, and the plurality of heads integrally relative to the plurality of disks. In a disk drive having a head driving means for moving the head, fine adjustment independent of the head driving means for finely adjusting a relative position between the plurality of heads according to an individual control signal for each of the plurality of heads. A disk drive having means. 2. A head device having a head for recording / reproducing information on / from a recording medium, and a head arm for supporting the head, wherein at least a part of the head arm is made of a piezoelectric material. A head device comprising means for externally applying a voltage to the piezoelectric material member.