JP2001338482A - Magnetic disk device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To achieve both high-speed rotation and highly accurate positioning by suppressing flutter vibration and head vibration, regarding the problem of the increase of head positioning errors caused by flutter vibration and head vibration increased by the high-speed rotation of a disk in a magnetic disk device. SOLUTION: By setting a space between a both-end disk surface and a base or the static wall surface of a cover equal to 1 mm or lower, flutter vibration is reduced. By installing a member in such a way as to prevent the flowing of an air flow from an actuator room into the vicinity of a head, head vibration is reduced. Thus, even in the recording device of high-speed rotation, head positioning accuracy is enhanced.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic disk drive, and more particularly to a magnetic disk drive capable of reducing fluid vibration caused by rotation of a disk and achieving high-precision positioning.

[0002]

2. Description of the Related Art In a magnetic disk drive, an increase in processing speed is required with an increase in capacity, and the number of disk rotations is gradually increasing. However, an increase in the number of rotations has caused a new problem as a cause of increasing disk vibration due to a fluid force generated with the rotation and lowering the positioning accuracy. As a conventional technique, Japanese Patent Laid-Open No. 11-232
As disclosed in Japanese Patent Publication No. 866, it is disclosed that by providing shrouds at predetermined intervals on the outer periphery of a disk, vertical vibration (hereinafter, flutter) of the disk can be reduced. Specifically, it is described that the distance between the outer periphery of the disk and the shroud is preferably larger than 0.1 mm and equal to or smaller than 0.6 mm.

[0003]

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention
Japanese Patent No. 2866 discloses the distance between the disk and the shroud in the radial direction, but the present invention also provides a method for reducing flutter vibration in the disks at both ends of the stacked disks.

[0004] In the magnetic disk drive, the data transfer speed is required to be increased in accordance with the increase in the storage capacity. With this, the rotational speed of the disk is gradually increasing, and this trend is expected to continue in the future. Is done. An increase in the number of rotations of the disk increases flutter vibration, which is the vibration of the disk, and is a main factor in increasing the positioning error of the head. Therefore, it is necessary to further reduce the vibration.

There are roughly two methods for reducing disk flutter.

[0006] One is a method of reducing the fluid force as an excitation source (strictly, averaging the pressure distribution), and the other is a method of increasing the rigidity of the disk to reduce the vibration. Although there is a method of increasing the plate thickness as a means for increasing the disk rigidity, an increase in the plate thickness is not preferable because it leads to an increase in the size of the apparatus.

An object of the present invention is to provide an apparatus which satisfies a reduction in flutter vibration caused by a positioning error caused by high-speed rotation and an improvement in positioning accuracy due to a large capacity.

[0008]

SUMMARY OF THE INVENTION The present invention provides a high-speed rotating large-capacity magnetic disk drive that prevents flutter by reducing a fluid force as an excitation source.

Specifically, the distance between the surfaces of the disks at both ends of the stacked rotating disks and the stationary wall surface of the base or cover is set to 1 mm or less. A pressure difference is generated between the upper surface and the lower surface of the disk surface due to the air flow generated by the rotation of the disk, which vibrates the disk and generates flutter vibration of the disk. By setting the distance between the surface of the disk at both ends and the stationary wall surface of the base or the cover to 1 mm or less, the flutter amplitude of the disk can be reduced. Further, by preventing the air flow from the actuator chamber from directly flowing into the vicinity of the head, it is possible to reduce head vibration. According to the above means, the positioning accuracy of the head can be improved even in a high-speed rotation recording apparatus.

[0010]

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

FIG. 1 is a top view of the entire apparatus. The magnetic disk 1 is stacked on a spindle motor 2 shaft, and a magnetic head 3 for recording / reproducing information is connected to a guide arm 4. The carriage 5 includes a guide arm 4, a pivot bearing 6, and a voice coil motor (hereinafter, VCM 7).
), And the guide arm 4 is rotated by the VCM 7 about the pivot bearing 6. These are installed on the base 10, and the periphery of the base 10 is surrounded by a wall (shroud wall 20). A predetermined distance is maintained between the outer periphery of the disk 1 and the inner wall of the shroud wall 20. A part of the shroud 20 includes a guide arm 4
An opening 30 is provided for inserting the disc on the surface of the disc 1. A wall is provided all around the base 10 of the device. On the disk side, the wall serves as a wall (shroud 20) surrounding the outer periphery of the disk,
In the vicinity of the opening 30, a wall (shroud 21) for surrounding the disk is provided separately from the above-mentioned wall.
The device is mounted on the entire peripheral wall of the base 10 via a packing 53,
The cover 50 is fixed and hermetically closed. When the disk 1 rotates in one direction, an air flow is generated with the rotation. For example, when the disk 1 rotates counterclockwise in FIG.
An air flow is generated in the direction of the arrow.

FIG. 2 shows a cross section of the disk chamber. One of the disk surfaces of the disk 1a at the lowermost position is opposed to the stationary wall surface of the base 10, and the other is opposite to the disk immediately above the lowermost disk. In such a case, since the upper surface and the lower surface of the lowermost disk face different surfaces of the rotating wall surface and the stationary wall surface, a pressure difference occurs in the air flow generated when the disk rotates, and this causes the disk 1a to vibrate. Flutter vibration is occurring. In order to reduce the flutter vibration, the gap between the lower surface of the lowermost disk 1a and the stationary wall of the base 10 is set to 1 mm or less.

On the other hand, the uppermost disk 1b is the same as the lowermost disk, and the gap between the upper surface of the uppermost disk 1b and the stationary wall of the cover 50 must be 1 mm or less. If the cover 50 is made of casting, the shape can be devised, and the gap between the upper surface of the uppermost disk 1b and the stationary wall of the cover 50 can be set to 1 mm or less as in the case of the lowermost disk 1a. However, when the cover 50 is made of sheet metal, the gap between the cover 50 and the disk is set to 1 mm with the precision of the drawing processing of the sheet metal.
It is difficult to:

In this embodiment, as shown in FIGS. 1 and 2, a shroud member A51 is attached to the surface of the sheet metal cover 50 except for the rotatable portions of the magnetic head 3 and the arm 4 so as to cover the uppermost disk. The gap between the upper surface of 1b and the stationary wall can be set to 1 mm or less.
The shroud member A51 is made of a material that also has a vibration damping action, so that the vibration of the cover 50 can be further reduced. When the shape is complicated, a resin-based material can be used.

Next, a second embodiment of the present invention will be described.

The arrows shown in FIG. 3 indicate the flow path toward the actuator chamber in the air flow generated by the rotation of the disk 1. A portion of the airflow travels from the disk chamber to the actuator chamber and back to the disk chamber. At this time, as shown in FIG. 4, if there is a gap between the shroud 21 near the magnetic head 3 and the cover 50, the airflow around the actuator chamber returns to the vicinity of the magnetic head of the uppermost disk 1b. The magnetic head vibrates due to this air flow, and the positioning accuracy deteriorates.

This improvement will be described with reference to FIG.

A shroud member B5 is attached to the cover 50 at the actuator chamber side portion of the shroud 21 near the magnetic head.
2 is applied to form a labyrinth serving as a pipe resistance between the shroud 21 and the shroud member 52 so that the air flow around the actuator chamber does not flow into the vicinity of the magnetic head. At this time, the shroud 21 and the shroud member 52
Is preferably 2 mm or less. Further, when the surfaces of the shroud 21 and the shroud member 52 facing each other are stepped, the pipe resistance is further increased, so that the air flow does not flow. As a result, the airflow around the actuator chamber is
It is possible to flow into the disk chamber from the section and suppress the vibration of the magnetic head.

[0019]

The flutter is reduced by making the distance between the surface of the disk at both ends of the laminated disk and the stationary wall surface of the base or the cover 1 mm or less, and the air flow entering from the actuator chamber is directly transmitted to the vicinity of the head. By preventing the flow, the head vibration can be suppressed, and a high-speed, large-capacity magnetic disk device can be provided.

[Brief description of the drawings]

FIG. 1 is a top view of a first and a second embodiment.

FIG. 2 is a cross-sectional view of the first and second embodiments.

FIG. 3 is a diagram showing a conventional example.

FIG. 4 is a diagram showing a conventional example.

[Explanation of symbols]

1: magnetic disk, 2: spindle, 3: magnetic head,
4 Guide arm, 5 Carriage, 6 Pivot bearing, 7 Voice coil motor, 10 Base, 20
... shroud (wall), 21 ... shroud (near the opening), 30 ... opening, 50 ... cover, 51 ... shroud member A, 52 ... shroud member B, 53 ... packing.

Claims (4)

[Claims] A plurality of magnetic disks serving as magnetic recording media; a spindle unit for rotating the group of magnetic disks;
A rotatable swing-type actuator section for holding a magnetic head for performing recording and reproducing operations of information on the magnetic disk and positioning the magnetic head at an arbitrary position in a radial direction of the magnetic disk; the spindle section and the actuator section A magnetic disk device comprising a base and a cover portion for housing and hermetically sealing, wherein a member for suppressing a flow of wind generated when the disk rotates is attached to the cover. 2. The magnetic disk drive according to claim 1, wherein a member for preventing wind from entering into the disk chamber from the actuator chamber in the flow of wind generated when the disk rotates is attached to the cover side. Magnetic disk drive. 3. The magnetic disk drive according to claim 1, wherein a clearance between the member that hinders the flow of wind and the surface of the disk is 1 m.
m or less. 4. The magnetic disk drive according to claim 1, wherein a material having a vibration damping effect is used for the member that blocks the flow of the wind.