JPS63213176A - Magnetic disk device - Google Patents

Abstract

PURPOSE:To compensate the error of head position due to abnormal vibration, by providing a sensor which detects the abnormal vibration such as to accelerate head access on a part of a housing, and processing a detecting signal, then inputting it to a driving amplifier. CONSTITUTION:An acceleration sensor 21 which detects the generation of the abnormal vibration in a direction of access is provided on a part of the housing which houses a magnetic disk 1 and a magnetic head 5, etc. When vibration due to earthquake or from the outside is received while the magnetic disk device is operated, the acceleration sensor 21 detects it, and a detected signal is changed to a servo compensating signal at a gain setting apparatus 22, and is supplied to an adder 23. At the adder 23, an ordinary head aberration compensating signal from a servo compensation circuit 11 in a head positioning control system and the signal from the gain setting apparatus 22 are added, and a driving motor 8 is driven by an added signal via a driving amplifier 12. Thus, the error of the head positioning due to external vibration can be compensated.

Description

[Detailed Description of the Invention] [Summary] The present invention provides a magnetic disk device in which a sensor for detecting abnormal external vibration that accelerates head access is provided in a part of the housing portion, and an acceleration signal proportional to the acceleration signal detected by the sensor is provided. The servo compensation signal generated by the magnetic head is added to the signal from the head positioning control system and inputted to the drive amplifier to drive the head drive motor, thereby compensating for the positioning error of the magnetic head caused by the above-mentioned abnormal external vibration. be.

[Industrial application field]

The present invention relates to improvements in magnetic disk drives, and more particularly to a device configuration that can easily compensate for a decrease in positioning accuracy of a magnetic head relative to a magnetic disk due to abnormal external vibrations.

In magnetic disk drives, it is extremely important to position the magnetic head at the selected trunk position with accuracy on the order of microns during recording and playback. Accurate positioning is required. Therefore, there is a need for a control system that quickly corrects head positioning errors due to external vibrations, or a configuration that is not susceptible to external vibrations.

[Conventional technology]

FIG. 3 shows a schematic configuration of a conventional magnetic disk device.

In the figure, l denotes a plurality of magnetic disks, and these magnetic disks 1 are held together by a hub mechanism 2 and mounted on a spindle 4 of a rotation mechanism 3. Reference numeral 5 denotes a magnetic head supported by a plurality of access arms 6, respectively. Reference numeral 7 designates a servo head (position signal magnetic head) also supported by the access arm 6, and reference numeral 8 designates a head drive motor comprising an actuator and the like that supports the plurality of access arms 6. These parts are arranged in a housing part 9 (airtight container) for dustproofing.

To position each magnetic head 5 at a target track position on one surface of the selected magnetic disk, the servo head 7 selects the head position information written in advance on the servo surface on the back surface of the lowest magnetic disk. This position signal is used to control the head drive motor 8 via the drive amplifier 12 to move the corresponding magnetic head 5 together with the other heads, and position it at a target track position on one surface of the selected magnetic disk. do.

However, if the magnetic head 5 is not accurately positioned at the target track position on the surface of the magnetic disk 1, that is, if a positional deviation occurs, the position signal demodulator 10 in the head positioning control system as shown in FIG. The difference between the deviation track position from the servo head 7 and the target track position is calculated by using the servo head 7, which is compensated by the servo compensation circuit 11 as a positioning error signal.
The head drive motor 8 is driven via the magnetic head 2 to accurately position each magnetic head 5 at a target track position on the corresponding magnetic disk surface.

[Problem that the invention seeks to solve]

However, when an earthquake or a large vibration is inadvertently applied from the outside to such a device configuration, it is impossible to compensate for all the head positioning errors caused by this by the servo compensation circuit 11 of the head positioning control system. Therefore, there was a drawback that each magnetic head 5 could not be accurately positioned at a target track position on the corresponding magnetic disk surface. Furthermore, depending on the magnitude of externally applied vibrations, there is also the problem that recording and reproducing information on the magnetic disk 1 becomes impossible.

SUMMARY OF THE INVENTION In view of the above-mentioned conventional circumstances, it is an object of the present invention to provide a new magnetic disk drive that reduces head positioning errors caused by earthquakes or external vibrations.

[Means for solving problems]

In order to achieve the above object, the present invention includes at least one magnetic disk mounted on a rotating mechanism, a magnetic head for recording and reproducing information on and from the magnetic disk, and a magnetic head that records and reproduces information on the magnetic disk. A sensor for detecting abnormal vibrations that accelerate head access is provided in a part of the housing housing the head drive motor that accesses the track position, and a servo compensation signal proportional to the abnormal vibration detection signal of the sensor is provided. A signal processing unit is provided to output the signal, and the signal from the signal processing unit and the signal from the servo compensation circuit of the head positioning control system are added together and inputted to the drive amplifier of the head drive motor to eliminate the head positioning error caused by the abnormal vibration. The structure is configured to correct.

[Effect]

In the magnetic disk device of the present invention, when an earthquake or external vibration is received, an abnormal vibration signal from a sensor that detects the addition of abnormal vibration provided in a part of the housing portion that accommodates the magnetic disk, magnetic head, etc. The signal is converted into a signal proportional to the signal in the signal processing section, and added to the positional deviation compensation signal from the servo compensation circuit of the head positioning control system.1. Since the signal is input to the drive amplifier of the head drive motor and compensated, head positioning errors caused by external vibrations are significantly reduced.

〔Example〕

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

FIG. 1 is a sectional view of a main part showing an embodiment of a magnetic disk device according to the present invention, and FIG. 2 is a block diagram showing an embodiment of a head positioning control system in a magnetic disk device according to the present invention. Parts that are equivalent to those in Figures 3 and 4 are given the same reference numerals.

The difference between this embodiment shown in these two figures and the conventional example shown in FIGS. 3 and 4 is that there is an abnormality in the head access direction in a part of the housing part 9 that airtightly accommodates the magnetic disk 1, magnetic head 5, etc. For example, an acceleration sensor 21 that detects the occurrence of vibration is provided, and a signal processing section that outputs a servo compensation signal proportional to the abnormal vibration detection signal of the acceleration sensor 21, such as a gain setting device 22 and the servo compensation signal circuit 1.
adder 2 that adds the head position deviation compensation signal from 1;
This is the point where 3 was added.

When a magnetic disk drive having such a configuration is subjected to an earthquake or external vibration during operation, an acceleration sensor 21 provided in a part of the housing section 9 that houses the magnetic disk 1, magnetic head 5, etc. Abnormal vibration in the access direction is detected.

The signal detected by the acceleration sensor 21 is converted into a servo compensation signal by a gain setter 22, and added to a normal head position deviation compensation signal from the servo compensation circuit 11 of the head positioning control system by an adder 23. The head drive motor 8 is driven by this added signal via the drive amplifier 12, and the relative positioning error of the magnetic head 5 with respect to the magnetic disk 1 in the housing part 9 caused by external vibration is compensated for, and It becomes possible to reduce the amount.

〔Effect of the invention〕

As is clear from the above description, the magnetic disk device according to the present invention not only compensates for normal head positioning errors but also has the advantage of significantly reducing head positioning errors due to earthquakes and external vibrations compared to conventional devices. It has many advantages.

Therefore, excellent effects can be achieved when applied to this type of magnetic disk device.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a main part showing an embodiment of a magnetic disk device according to the present invention, FIG. 2 is a block diagram showing an embodiment of a head positioning control system in a magnetic disk device according to the present invention, and FIG. 4 is a sectional view of a main part of an example of a conventional magnetic disk device, and FIG. 4 is a block diagram showing a head positioning control system in a conventional magnetic disk device. 1 and 2, 1 is a magnetic disk, 2 is a hub mechanism, 3 is a rotation mechanism, 4 is a spindle, 6 is an access arm, 7 is a servo head,
8 is a head drive motor, 9 is a housing section, 10 is a position signal demodulator, 11 is a servo compensation circuit, 12 is a head drive amplifier, 21 is an acceleration sensor, 22 is a gain setter, and 23 is an adder.

Claims (1)

[Claims] At least one magnetic disk (1) mounted on a rotating mechanism (3), a magnetic head (5) for recording and reproducing information on and from the magnetic disk (1), and a magnetic head (5) for recording and reproducing information on the magnetic disk (1). Magnetic head (5
) to access any track position on the disk surface, and a housing part (9) that houses these motors. A sensor (21) for detecting such abnormal vibration is provided, and a signal processing section (22) is provided for outputting a servo compensation signal proportional to the abnormal vibration detection signal of the sensor (21), and the signal processing section (22) The signal from the head drive motor (8) is added to the signal from the head positioning control system.
) to a drive amplifier (12) that drives the magnetic disk drive to compensate for a head positioning error caused by the abnormal vibration.