JP2002199686A - Disk device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To secure high reliability of a disk device by previously detecting abnormality of a fluid bearing device before it does not function and preventing the reproduction of data stored to a disk from being unable. SOLUTION: In the disk device provided with the fluid bearing device rotatably supporting the rotator of a spindle motor, and a position erroneous detection circuit 23 outputting the position erroneous signal of a head 20 on the basis of servo data on the disk 11 read from the head 20, the deflection of the whirl component of a bearing produced within the frequency range of the rotary frequency or less of the spindle motor is detected on the basis of the servo data, and when the amplitude value of the deflection of the whirl component exceeds a prescribed value, a bearing abnormality detection circuit 31 outputting the abnormal signal is provided.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement in a disk device such as a magnetic disk device (HDD) and an optical disk device used for video and information equipment.

[0002]

2. Description of the Related Art FIG. 2 shows a spindle motor structure of a magnetic disk drive using a hydrodynamic bearing device. In this spindle motor, a hub 2 is concentrically fixed to an upper end of a rotating shaft 1, a rotor (magnet part) 3 is attached to an inner peripheral portion of the hub 2, and one or a plurality of rotors are attached to an outer peripheral portion of the hub 2. Disc 1
1 is mounted.

The rotating shaft 1 is fitted into a sleeve 5 fitted to a cylindrical portion 4a of a base 4 with a predetermined gap, and a stator 6 is attached to the outer peripheral portion of the cylindrical portion 4a so as to face the rotor 3. Have been. Inner peripheral surface of the sleeve 5 and / or
Alternatively, a groove (not shown) for generating dynamic pressure is provided on the outer peripheral surface of the rotating shaft 1, and the outer peripheral surface of the rotating shaft 1 and the inner peripheral surface of the sleeve 5 constitute a radial dynamic pressure bearing. I have.

A thrust plate 9 is fixed to a lower end of the rotating shaft 1, and the thrust plate 9 is opposed to a counter plate 10 fixed to a lower end of the cylindrical portion 4 a of the base 4. Thrust plate 9
Grooves (not shown) for generating dynamic pressure are provided on at least one surface of both surfaces of at least one of the mating members (the lower end surface of the sleeve 5 and the counter plate 10) opposed to the both surfaces to constitute a thrust fluid bearing. are doing. Lubricants such as oil and grease are sealed in the bearing clearances of the radial dynamic pressure bearing and the thrust fluid bearing.

[0005] A rotating body constituted by the rotating shaft 1, the hub 2, the rotor 3 and the like is supported in the radial direction via a radial dynamic pressure bearing, and is supported rotatably around the stator 6 to generate the stator 6. The rotating body is integrally rotated by the rotating magnetic field. As described above, in the case of the spindle motor using the hydrodynamic bearing device, the NRRO (non-rotational synchronous component runout) of the motor is smaller than that of the spindle motor using the ball bearing. In addition, since there is no sound generated in the bearing, the noise of the entire magnetic disk device can be reduced. For this reason, the development of a hydrodynamic bearing spindle motor for a magnetic disk drive has recently been active.

[0006]

However, in a spindle motor using a hydrodynamic bearing device, when used for a long period of time, the lubricant in the bearing clearance gradually decreases due to evaporation and scattering, and the amount of lubricant decreases. When the amount is less than the predetermined amount, whirling, which is unstable vibration having a frequency lower than the rotation frequency of the spindle motor, is generated.

When the amount of the lubricant further decreases, the amplitude of the whirl gradually increases, and metal contact between the rotating shaft 1 and the sleeve 5 occurs, resulting in burn-in. As a result, the magnetic disk device does not function. There is a possibility that data recorded on the disk 11 may not be able to be reproduced, and there is an unsolved problem that it is difficult to ensure the reliability of the device.

The present invention has been made in order to solve such inconveniences, and it is possible to greatly improve the recording density of a disk and to reduce noise as well as completely functioning. An object of the present invention is to provide a disk device capable of preventing data from being unable to be reproduced by detecting an abnormality of the hydrodynamic bearing device in advance before the failure occurs, thereby ensuring high reliability.

[0009]

In order to achieve the above object, a disk drive according to the present invention comprises a fluid bearing device rotatably supporting a rotating body of a spindle motor, and a disk mounted on the rotating body. A head for recording data on and / or reproducing data previously recorded on the disk, and a position error detection for outputting a position error signal of the head based on servo data on the disk read from the head A disk drive provided with a circuit for detecting a vibration of a whirl component of a bearing generated in a frequency range equal to or lower than a rotation frequency of the spindle motor based on the servo data, and determining an amplitude value of the whirl of the whirl component to a predetermined value. The bearing is equipped with a bearing abnormality detection circuit that outputs an abnormality signal when the value exceeds the value. It is preferable to detect a frequency range of １ ／ to ／ of the rotation frequency of the rotor as a whirl component of the bearing. Also, regarding the bearing abnormality detection circuit, the amplitude value of the whirl detection signal obtained by the whirl component detection circuit It is preferable to output an abnormal signal when the value exceeds a predetermined value of 2 nm or more.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram for explaining a magnetic disk drive according to an embodiment of the present invention. In this embodiment, a magnetic disk device is taken as an example of a disk device, and a fluid bearing spindle motor built in the magnetic disk device is the same as that shown in FIG.

In FIG. 1, reference numeral 20 denotes a disk 1 by accessing a data sector or a servo sector on the disk 11.
1 is a head (magnetic head) for recording data on the disk 1 and reproducing data recorded on the disk 11, and the head 20 is attached to the tip of a support arm 21. In this embodiment, the support arm 21 is rotatably driven by a voice coil motor (VCM) 22 so that the rotation of the support arm 21 moves the head 20 in the radial direction of the disk 11. Has become.

Reference numeral 23 denotes a position error signal of the head 20 based on servo data read by the head 20 (specifically, position data for positioning the head 20 positioned by seek control at a track center). Is a position error detection circuit that generates and outputs the same.
The position error signal from the position error detection circuit 23 is converted into digital data by the A / D converter 25 and then input to the position control circuit 26. The position control circuit 26 executes a position error calculation process, outputs a control amount such that the calculation result (position error) gradually matches “0”, and drives the VCM drive circuit via the D / A converter 27. 28. Thereby, the feedback control for rotating the support arm 21 by the voice coil motor 22 in accordance with the control amount and positioning the head 20 at the center of the track is performed.

In this embodiment, the position error signal generated by the position error detection circuit 23 is input in parallel to the whirl component detection circuit 30 and the whirl component detection circuit 3
The presence / absence of a whirl component and the amplitude value of the hydrodynamic bearing device are detected by 0. The bearing abnormality detection circuit 31 is configured to compare the Whirl amplitude value detected by the Whirl component detection circuit 30 with a predetermined specified value and output an abnormal signal when the Whirl amplitude value exceeds the specified value. I have.

The frequency of the whirl detected by the whirl component detection circuit 30 is １ ／ to ／ of the rotation frequency of the spindle motor. Usually, a whirling frequency of about 1/2 of the rotation frequency of the spindle motor appears in such a setting, but in some cases, 1/4, 1/3,
This is because whirling in a frequency range of 2/3, 3/4, or the like may appear, and an abnormality in the bearing may not be accurately detected even if only 1/2 frequency is monitored.

The specified value in the bearing abnormality detection circuit 31 is set to 2 nm or more. The reason for setting the specified value to 2 nm or more is that when the specified value is less than 2 nm, tracking failure occurs.
This is because an abnormal signal of the hydrodynamic bearing device is output before a problem of performance failure of the magnetic disk device such as (data read / write failure) occurs, which is not preferable for the magnetic disk device as a whole. It should be noted that since the optimum value varies depending on each hydrodynamic bearing device, it is preferable to set a specific value specific to each hydrodynamic bearing device by experiment or the like within a range of 2 nm or more.

When an abnormality signal is output from the bearing abnormality detection circuit 31, a warning to the effect is displayed on the display, a lamp or the like is turned on or blinked, or a sound is output. This makes it possible to replace the magnetic disk device before the magnetic disk device completely stops functioning, or to store data recorded on the disk in another magnetic disk device.

As described above, according to this embodiment, it is possible to know the abnormality of the hydrodynamic bearing device before the magnetic disk device completely stops functioning, so that it is possible to prevent sudden burning of the hydrodynamic bearing device, and furthermore, It is possible to replace the magnetic disk device before the magnetic disk device completely stops functioning or to store data recorded on the disk in another magnetic disk device. This makes it possible to avoid that data cannot be reproduced, thereby ensuring high reliability of recorded data.

Further, since the spindle motor using the hydrodynamic bearing device is used, the recording density of the disk 11 can be greatly improved, and since there is no sound generated in the bearing, the noise of the entire magnetic disk device is reduced. be able to. In the above embodiment, the case where the present invention is applied to a magnetic disk device is taken as an example. However, it goes without saying that the present invention may be applied to an optical disk device having a read-only head.

Further, the hydrodynamic bearing device is not limited to the above embodiment, but the present invention can be applied if the radial bearing is a hydrodynamic bearing.

[0020]

As is apparent from the above description, according to the present invention, not only the recording density of the disk can be greatly improved and the noise can be reduced, but also the disk can function completely. Since it is possible to detect in advance the abnormality of the hydrodynamic bearing device before it disappears and prevent the data recorded on the disk from being unable to be reproduced, it is possible to obtain an effect that high reliability of the disk device can be secured. Can be

[Brief description of the drawings]

FIG. 1 is a block diagram for explaining a magnetic disk drive which is an example of an embodiment of the present invention.

FIG. 2 is an explanatory cross-sectional view for explaining a spindle motor structure of a magnetic disk drive using a hydrodynamic bearing device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 ... Disk 20 ... Head 23 ... Position error detection circuit 30 ... Whirl component detection circuit 31 ... Bearing abnormality detection circuit

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Shigeyuki Ochiai 1-5-50 Kugenuma Shinmei, Fujisawa-shi, Kanagawa F-term in NSK Ltd. (reference) 3J011 AA20 BA04 BA06 CA02 EA05 JA02 KA02 KA03 MA21 5D109 BB01 BB12 BB18 BB21 BB22 CA04 5H019 AA06 BB01 CC04 DD01 FF01 FF03 5H607 AA04 BB01 BB07 BB09 BB14 BB17 BB25 CC01 CC05 DD16 FF12 GG01 GG02 GG09 GG12 GG15 HH01

Claims (1)

[Claims] 1. A fluid bearing device rotatably supporting a rotating body of a spindle motor, and for recording data on a disk mounted on the rotating body and / or reproducing data previously recorded on the disk. And a position error detection circuit that outputs a position error signal of the head based on servo data on the disk read from the head, the spindle motor based on the servo data A bearing abnormality detection circuit that detects a vibration of the whirl component of the bearing generated in a frequency range equal to or lower than the rotation frequency of the bearing and outputs an abnormality signal when an amplitude value of the vibration of the whirl component exceeds a predetermined value. Characteristic disk device.