JPH01241058A - Disk driving device - Google Patents

Abstract

PURPOSE:To prevent the erazing of a bit of servoinformation as an over-light on the bit of prewritten servoinformation by detecting the position of a servosector by the rotary period of an information recording disk. CONSTITUTION:The servosignal arranged in zigzags is read at the time when the gap G of a magnetic head 2 is located at a 1st servosector S1 and the output from a head amplifier 21 is compared by a comparison circuit 30 by discriminating it by sample/hold circuits 28, 29 at the process of tracking a recording track Tn. In this control method the servosignal is read one per 1/2 rotation and the servocontrol is performed, if necessary, but in such the case, the timing exerting the light protection on a 2nd servosector is corrected by detecting the rotary period, so the dissipation of the servo-pattern written in advance on the 2nd servosector can be prevented.

Description

[Detailed Description of the Invention] [Industrial Application Field] This invention drives an information recording disk to record information.
3/ This invention relates to a disk drive device that performs reproduction, and particularly relates to a disk drive device that drives a disk having a plurality of servo sectors.

[Conventional technology]

Various types of disk drives are known for recording and/or reproducing information by rotationally driving an information recording disk, for example, a disk-shaped magnetic recording disk (hereinafter referred to as a magnetic disk). However, for devices that are particularly small and require a large amount of information, disk drives, also called hard disk drives, are often used. A magnetic disk on which a recording layer is formed is rotated at high speed, and a magnetic head is floated above the surface of the magnetic disk to perform recording/reproduction.

An example of this type of disk drive is shown in FIG. In the figure, the disk drive device includes a magnetic disk 1 for recording information, a magnetic head 2 for recording/reproducing information on the magnetic disk 1, and a direct drive (not shown) for rotationally driving the magnetic disk 1. Motor (hereinafter referred to as
(referred to as a DD motor), a head drive mechanism 4 for moving the magnetic head 2 to a predetermined track on the magnetic disk 1, and a base of a casing that houses the magnetic disk 1, the magnetic head 2, etc. and maintains it in a sealed state. The base plate 5 becomes
It mainly consists of a printed circuit board 6 on which a motor drive circuit, a control circuit, etc. are formed, and a frame (not shown) for attaching this printed circuit board 6 to the base plate 5.

In this magnetic disk device, the magnetic disk 1 is
Two magnetic heads 2 are provided, and since double-sided recording is performed on one magnetic disk 1, one magnetic head 2 is provided on each surface, a total of four magnetic heads 2 are provided. It is attached via a support spring. The head drive mechanism 4 consists of this swing arm 8, a steel belt 9 attached to a part of the swing arm 8, a pulley 10 around which the middle part of the steel belt 9 is wound, and a stepping motor 11. The pulley 10 around which the steel belt 9 is wound is inserted into the drive shaft 12 of the stepping motor 11 and fixed, and the stepping motor 1
1, the swing arm 8 can be swung around the rotating shaft 8a.

Magnetic disk 1. Magnetic head 2. Swinger 58. The casing that houses the steel belt 9, pulley 10, etc.
Consisting of the base plate 5 and a top cover (not shown), gaskets are used at the contact area between the base plate 5 and the top cover and at the mounting area of the stepping motor 11 to maintain airtightness, and magnetic fluid is used at the shaft of the DD motor. is filled. Further, a shutter 17 is provided on the antimagnetic head mounting side 8b of the swing arm 8 so as to protrude outward. Furthermore, the airtight chamber 5 of the base plate 5
A photointerrupter 18 is provided as an outside sensor on the a side, and an insertion path 18a of this photointerrupter 18 is provided as an outside sensor.
The shutter 17 is arranged so as to be loosely inserted therein. In this conventional example, when the magnetic head 2 reaches the zero track position on the outer periphery, the shutter 17 blocks the optical path formed in the insertion path 18a of the photointerrupter 18.

By the way, when moving the magnetic head 2 using the stepping motor 11 as described above, it becomes difficult to position the head as density increases. In other words, in hard disk devices, the materials inside the device have different coefficients of thermal expansion.
There is a problem called thermal off-track, where the position of the magnetic head 2 relative to the track shifts due to temperature changes.
Therefore, in a 5.25-inch hard disk drive, for example, it is generally difficult to position the magnetic head 2 without using a servo when the value exceeds 4007 PI.

One of the control methods using this servo is JP-A-57-86.
There is an invention disclosed in No. 910. This invention uses one data-masked servo sector containing track centerline servo control data that can be successively output by the head to position the head from servo information once per revolution of the magnetic disk. ing. therefore,
In this type of servo control system, servo information is embedded in only one location per revolution, so after moving the head, it is necessary to wait for rotation until the servo information is read.

Another control method using servos is to use the innermost and outermost tracks as dedicated servo tracks. This method uses the inner diameter (I 1si-de Dia
meter ), outside diameter
This is an abbreviation of ID-OD method.

In this method, the disk device first reads the outer servo track and makes fine adjustments so that the head is centered on the track. The head is then moved toward the inner servo track. At this time, the number of step pulses of the stepping motor of the head drive mechanism is applied, and when the head reaches the inner servo track, the head positioning mechanism performs precise positioning so that the head is in the center of the track. Let's do it. Then, during precise positioning of each servo track, the positioning mechanism learns the amount of correction needed to find the center of the track. Once this correction is known, the positioning mechanism can calibrate the exact position of each track with information about the number of chip pulses required to move between the outer and inner tracks and the amount of microstep correction required on each servo track. It is now possible to do so.

However, with this method, the positioning mechanism has to repeat the calibration procedure every time a positioning error occurs, so if this happens frequently, a lot of time is wasted that is not directly related to recording/playback. , the utilization efficiency of the disk drive decreases. Also, once the head is on the data track, there is no guarantee that the head will be held in the correct position since there is no means for readjustment. ” Based on these facts, the present applicant proposed the invention disclosed in Japanese Patent Application Laid-Open No. 62-298974 as a means to solve the above problems.

This application relates to a recording medium drive device that writes or reads signals to or from a recording track on an information recording medium via a head device, and a method for positioning the head device with respect to the recording track. First and second servo sectors in which servo information corresponding to each recording track is written are formed symmetrically with respect to the center in the radial direction of the recording medium, and the servo information is read by a head device every half rotation. The excitation voltage supplied to the motor for moving the head is controlled by comparing the signal levels of , and the head device is positioned at a fine track position with respect to the recording track.

[Problem that the invention seeks to solve]

However, with this configuration, it is necessary to write protect the first and second servo sectors. For this reason, both servo sectors are write-protected based on the internal index, but when writing-protecting two servo sectors from one internal index, for example, the first servo sector is Apply write protection,
The second servo sector is write-protected when a preset time has elapsed since the input of the internal index signal. Therefore, when a rotational fluctuation of the motor occurs, the position where write protection is applied shifts when viewed microscopically. Therefore, if the rotational fluctuation becomes large due to some reason such as an external shock or a fluctuation in the drive voltage, the position where the write protection is applied will shift significantly, and in the worst case, the pre-written servo pattern will be erased and the head positioning will be changed. There is a risk of loss of control.

On the other hand, in order to solve this problem,
As disclosed in No. 74, two internal indexes can be provided corresponding to two servo sectors, but two detection means must be provided correspondingly.
The cost increases accordingly.

This invention was made in view of the actual state of the prior art as described above, and its purpose is to improve accuracy without increasing costs (write protection can be applied, so that data written in the servo zone can be It is an object of the present invention to provide a disk drive device that eliminates the possibility of erasing servo information and can reliably perform servo control of blade positioning.

[Means for solving problems]

In order to achieve the above object, the present invention provides a disk drive for rotating an information recording disk having a plurality of servo sectors in which servo information is written in advance in the radial direction, and writing and/or reading information via a head device. In the apparatus, means for detecting the rotation period of the information recording disk, means for calculating the position of the servo sector from the rotation period detected by the means for detecting the rotation period, and when the head device is located at the calculated servo sector position. and means for disabling writing to the information recording disk by outputting a write protect signal to the information recording disk.

[Effect]

According to the above means, the position of the servo sector is detected based on the rotation period of the information recording disk, so even if the rotation period changes, the position where write protection is applied is accurate, and the servo sector information written in advance is overwritten. This eliminates the risk of erasing servo information.

〔Example〕

Hereinafter, one embodiment of the present invention will be described based on the drawings.

In the following description, components that are the same or can be considered to be the same as those of the conventional example shown in FIG. 6 are given the same reference numerals, and overlapping descriptions will be explained appropriately.

FIG. 3 shows a control system of a disk drive device according to an embodiment. The control system of the disk drive device includes a drive circuit 22 that controls the DD motor 3 that rotates the magnetic disk 1 and the stepping motor 11 that swings the swing arm 8, and that sends and receives signals to and from the head amplifier 21. , a servo circuit 2 that processes servo information read by the magnetic head 2 and amplified by the head amplifier 21 and sends an electric signal related to servo control to the drive circuit 22.
3 and a controller 25 that controls the drive circuit 22 via an interface 24. The controller 25 and host computer 26 are connected by a bus 27, and are capable of processing signals detected by the magnetic head 2 or signals sent to the magnetic head 2.

FIG. 4 shows the servo sectors and data zones formed on the magnetic disk 1. The magnetic disk 1 is made of, for example, an aluminum TR'r coated with a magnetic coating, and has an inhibit zone I where data is not written on the innermost circumference side, and a data zone and a servo sector (servo zone) on the outer circumference side. is divided in the radial direction.

The servo sector consists of a first servo sector S1 and a second servo sector S2, both of which are provided at symmetrical positions with respect to the center of the magnetic disk 1 so as to divide the data zone into two. The data zone includes a first data zone D located downstream of the first servo sector S1 with respect to the rotational direction R of the magnetic disk 1, and a second data zone D2 located downstream of the second servo sector S2. For example, over 600 recording tracks T are provided starting from the outermost recording track.

As shown in FIG. 1, the first and second servo sectors S, St have the same servo signal F at positions equidistant from each recording track T with respect to its longitudinal (circumferential) center vAC. They are written alternately in a staggered manner depending on the frequency. In this case, since writing is performed using the same magnetic head 2,
The track width of the servo signal F and the recording track T matches the width of the gear 270 of the magnetic head 2, and off-track occurs when the position of the gap G of the magnetic head 2 deviates from the desired recording track T.

Furthermore, in this disk drive, since servo sectors are formed at two locations as described above, it is necessary to provide internal indexes at two locations.

To deal with this, for example, as shown in Figure 2,
A magnet (hereinafter referred to as PG magnet) is installed as a pulse generating means on the outer periphery of the rotor 3a of the D motor 3.
40 is attached, and the magnetic change from this PG magnet 40 is detected by a detection means (hereinafter referred to as a PG sensor) such as a coil or a wheel element provided near the outer periphery of the rotor 3a of the DD motor 3. ) 42 and is used as the internal index signal IN. This internal index signal IN corresponds to the start of the first servo sector S, as shown in FIG. read out. Then, counting starts when the internal index signal IN is detected, and when the preset count number <I is reached, the external index signal EIN is sent to the host computer 26 side. The external index signal EIN with the first
This indicates the start of data zone D, and recording/reproduction is performed from this external index signal EIN detection position. A second servo sector S2 exists at a position where the magnetic disk 1 has rotated 180 degrees, and this second servo sector S2 converts changes in the magnetic field caused by the PC magnet 40 to the PG sensor 42.
It is estimated that the position is at a position where 1/2 period has passed since detection. That is, each time the magnetic disk 1 rotates, the PG sensor 42 detects the period S3 of one rotation.
The rotation period is detected by a detection circuit in the microcomputer in the drive circuit 22. Then, the calculation circuit in the microcomputer calculates the position of the second servo sector S2 by averaging the rotation period, for example, five times, and the write control circuit in the microcomputer outputs a write protect signal according to the calculated result. Set it to H" to make writing impossible. After that, the write protect signal is set to "H" for a preset count number (time), and when the count number elapses, the write protect signal is set to "L", so that the write protect signal is set to "L" for the second data zone D2. Enable writing. Further, when the write protect signal is further rotated by 180 degrees from the position where the write protect signal is set to "H", the internal index signal IN is obtained by the PG sensor, indicating that one rotation has been made from the position where the internal index signal is generated.

Next, the operation of the disk drive device configured as described above will be explained.

In this kind of disk drive device, the excitation phase and excitation voltage of each recording track T and the stepping motor 11 are stored in advance in a control means such as a microcomputer, and the correspondence between the recording track T and each rotation of the stepping motor 11 is established. The magnetic head 2 is positioned by selecting the rotation angle, that is, by controlling the excitation phase and excitation voltage.

Therefore, during operation, the drive circuit 22 selects one of the recording tracks T7 to be recorded/reproduced based on a command from the host computer 26.

In the process of tracking the recording track T7, the gap G of the magnetic head 2 moves to the first servo sector S in FIG.
5, outputs from the head amplifier 21 are discriminated by sample/hold circuits 28 and 29, and compared by a comparison circuit 30.

When the output from the comparison circuit 30 exceeds a preset level, a servo control signal is sent from the servo amplifier 31 to the drive circuit 22, and the excitation voltage of the stepping motor 11 is controlled in accordance with the servo control signal. is carried out. As a result, the gap G is located at the fine track position of the recording track TII.

The time it takes for the magnetic head 2 to detect a servo signal, compare the servo signals, correct the position, and converge to a fine track position and stabilize is approximately 3.
It is m5ec. On the other hand, since the time required for one rotation of the magnetic disk 2 is approximately 16.67 m5ec at 3600 rpm, immediately after reading out the servo signal F and stabilizing it,
Next servo signal F (in this case, second servo sector St
The servo signal F) written in the servo signal F) will be read out.

As a result, the result of servo control from the servo signal F in the first servo sector SI is transferred to the second servo sector S2.
This can be confirmed by the servo signal F at . As a result of this confirmation operation, if it is at the fine track position, tracking is performed as it is; if it is not yet at the preset fine track position, position control is performed again, and the servo signal at the next first servo sector S is In other words, in this control method, the servo signal is read out once every 1/2 rotation and servo control is performed as necessary. At that time, the rotation period is detected and the second Since the timing at which write protection is applied to the second servo sector is corrected, it is possible to prevent the servo pattern written in advance in the second servo sector from disappearing. Thereby, head positioning control operation using two servo sectors can be guaranteed at all times.

In the above embodiment, a hard disk drive that rotationally drives a hard magnetic disk was used as an example, but it is also possible to write servo information on the recording medium side and perform tracking control based on this servo information. Needless to say, it can be applied to everything.

Furthermore, although the above embodiments are exemplified with two servo sectors, it goes without saying that the present invention can also be applied to systems with three or more servo sectors. Further, in the above embodiment, the detection position of the magnetic field change by the PG sensor 42 and the start position of the first servo sector are partially located, but this can also be selected as appropriate depending on the design conditions.

〔Effect of the invention〕

As is clear from the above explanation, there is a means for detecting the rotation period of the information recording disk, a means for calculating the servo sector position from the detected result, and a write protect signal when the head device is located at the calculated servo sector position. According to the present invention, the servo sector position is calculated from the rotation period, so even if the rotation fluctuation becomes large, there is no error in the position where write protection is applied. is minimized, and there is no risk of overriding and erasing servo information previously written on the servo sector. Therefore, there is no possibility that head positioning control using servo information will become impossible. In addition, since two or more sensors are not particularly required in this case, an increase in cost will not be caused.

[Brief explanation of the drawing]

1 to 5 are for explaining a disk drive device according to an embodiment of the present invention, in which FIG. 1 is an explanatory diagram showing recording tracks of a magnetic disk and the writing state of servo signals, and FIG. 3 is a block diagram showing the control system, FIG. 4 is an explanatory diagram showing the area of the magnetic disk, FIG. 5 is a block diagram showing an example of a servo circuit, and FIG. 6 is a conventional block diagram. FIG. 2 is a partially cutaway perspective view of a disk drive device, showing a specific example of the disk drive device from FIG. 1...Magnetic disk, 2...
... Lf! Head, 3...DD motor, 8...Swing arm, 11...
...Stepping motor, 21...
・Head amplifier, 22... Drive circuit, 2
3... Servo circuit, DI...
...First data zone, D2...Second
Data zone, F... Servo signal, S
I......First servo sector, S2...
...Second servo sector, T...
- Recording track, IN...Internal index signal. :iJ+ Figure, 53j -〇Figure 4 I S2 I Figure 5

Claims (1)

[Claims] Detects the rotation period of the information recording disk in a disk drive device that rotates an information recording disk having a plurality of servo sectors in which servo information is written in advance in the radial direction, and writes and/or reads information via a head device. means for calculating the position of the servo sector from the rotation period detected by the means for detecting the rotation period; and means for outputting a write protect signal to provide information when the head device is located at the calculated servo sector position. A disk drive device comprising: means for disabling writing to a recording disk.