JP2001167506A - Magnetic disk unit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To eliminate the possibility that data are misread or miswritten because a magnetic disk shift radially from a spindle caused by an external shock. SOLUTION: A magnetic disk holding means is provided which holds the outer peripheral end of the disk in contact when the disk is stopping and leaves the disk when the disk is rotating. Consequently, the shock resistance of the magnetic disk drive can be improved and then a radial shift of the disk due to an external shock and the amplitude of the vertical vibration of the disk can be reduced.

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 for recording and reproducing information, and more particularly to a magnetic disk drive which is resistant to external impact.

[0002]

2. Description of the Related Art A conventional magnetic disk drive employs a magnet latch mechanism for fixing a magnetic head at a predetermined radial position (contact / start / stop zone) when the magnetic disk is stationary. As described in, for example, Japanese Patent Application Laid-Open No. Hei 9-167304, a magnet latch mechanism is used to move a magnetic head to the contact / start / stop zone (hereinafter referred to as CSS) when the magnetic disk is stationary.
Zone). It is described that this makes it possible to prevent the magnetic head from coming into contact with the data zone of the magnetic disk to cause a so-called sticking problem (a problem that the disk and the slider stick and the disk does not rotate). It is also known that the hub is fixed at the time of shipment to prevent the disk from rotating, but this is only to prevent the disk from rotating.
It does not prevent displacement of the magnetic disk from the spindle due to external impact, and does not improve impact resistance.

[0003]

According to the present invention, the magnetic disk drive receives an external impact, and
It is an object of the present invention to prevent a relative positional relationship with a spindle holding a magnetic disk from shifting.
More specifically, one or more magnetic disks stacked on the spindle are sandwiched between the hub end surface of the spindle and the disk clamp, and are fixed by a pressing force (axial force) due to a spring force due to the bending of the disk clamp. I have. Since the inner diameter of the disc is slightly larger than the outer shape of the spindle because the spindle is inserted, there is a gap between the two. Therefore, the magnetic disk drive is perpendicular to the axial direction of the spindle,
Alternatively, when a large external impact (impact acceleration) is applied in the horizontal direction, the disk shifts in the radial direction of the disk (in the direction perpendicular to the spindle axis direction). On the magnetic disk, a positioning signal (servo signal) is recorded in advance on a circle concentric with the rotation center of the spindle. For this reason, when a large impact acts on the magnetic disk device and the magnetic disk is displaced in the radial direction, the rotational center of the servo signal track written concentrically (track-like) with the rotational center of the spindle is displaced, and in the worst case In addition, the magnetic head cannot be positioned at a predetermined radial position, or the time required for positioning at the predetermined radial position (data access time) increases, and the reliability of the magnetic disk drive or the data access performance increases. There is a problem of lowering the position of the magnetic disk in the radial direction due to a large impact. An object of the present invention is to solve this problem and to provide a magnetic disk device that is resistant to impact.

[0004]

In order to solve the above-mentioned problems, a magnetic disk holding means is provided for holding the outer peripheral end of the magnetic disk in contact when the magnetic disk is stationary, and separating from the magnetic disk when rotating the magnetic disk.

As means for determining whether the magnetic disk is stationary or rotating, there is, for example, a method of determining whether there is an electromotive force due to the rotation of the magnetic disk. In addition, by estimating the following transient time in advance, if there is no power supply for driving the magnetic disk from the personal computer equipped with the magnetic disk device, the disk is stopped when the rotational deceleration transient time has elapsed. When power is supplied to drive the magnetic disk, it is possible to determine that the disk is rotating after the elapse of the rising delay time.

The magnetic disk holding means is a piezo element, a shape memory alloy, a solenoid, or the like, so that a power supply for driving the magnetic disk device is diverted, and when the disk is stationary, the disk is held in contact to prevent the disk from shifting. A mechanism that separates from the disk during rotation can be easily realized.

Furthermore, the magnetic disk holding means can prevent the disk from being displaced irrespective of the direction of the external impact by contacting and holding the magnetic disk at at least three places.

[0008] Further, it is detected that the disk has stopped,
By providing a sensor or a delay circuit for starting the disk holding, the reliability of the magnetic disk holding means can be improved.

Further, by providing a sensor or a delay circuit for starting disk rotation after detecting that the magnetic disk holding means has separated from the disk or after elapse of time required to separate from the disk,
The reliability of the magnetic disk holding means can be improved.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the present invention will be described with reference to FIGS.

FIG. 1 shows a magnetic disk holding means 10 according to the present invention.
1 shows a magnetic disk drive equipped with a. Figure 2
FIG. 2 shows a cross-sectional view when the AA cross section is viewed from the arrow side.
A magnetic disk 1 for recording information is mounted on a spindle 9 and pressed and fixed by a disk clamp 2. A slider 3 having a magnetic head for recording and reproducing information on the magnetic disk 1 is supported by a magnetic head support mechanism 4, is rotated around a pivot bearing 5 by a voice coil motor 6, and is positioned at an arbitrary radial position. . Here, magnetic disk holding means 10 are provided at three locations on the outer peripheral end of the magnetic disk 1. When the magnetic disk 1 is stationary, the magnetic disk holding means 10 contacts and holds the outer peripheral end of the magnetic disk 1 as shown in FIG. These components are sealed by a base 7 and a cover (not shown).

In this embodiment, the magnetic disk 1 is placed on a spindle hub 91 and fixed by being pressed by a disk clamp 2. More specifically, the disk clamp 2 is bent by tightening the disk clamp 2 with the screw 8, and the magnetic disk 1 is pressed in the direction of the spindle hub 91 by the force (axial force) generated thereby to fix the disk. I have. Here, magnetic disk 1
Has shown the example which is fixed by the screw and the disk clamp, but the present invention can be applied to the case where it is fixed by shrink fit instead of the screw.

Since the inner diameter of the disk 1 is made slightly larger than the outer diameter of the spindle 9 because the spindle 9 is inserted, there is a gap between the two. For this reason, in the conventional magnetic disk drive, there is a problem that the disk moves in this gap due to an external impact and is displaced in the disk radial direction.

However, in this embodiment, the magnetic disk holding means 10 can prevent the disk from shifting due to an external impact. The magnetic disk holding means 10 will be described in detail. The magnetic disk holding means 10 includes a movable part 11 and a fixed part 12, and one end of the fixed part 12 is attached to the base 7. The other end of the movable portion 11 is in contact with and holds the outer peripheral end 1a of the magnetic disk 1. In the present embodiment, a piezo element that expands and contracts by an applied voltage is used for the movable unit 11. However, besides the piezo element,
Any material or mechanism having the property of expanding and contracting by applying a voltage, such as a shape memory alloy or a solenoid, may be used. When the disk is stationary, the magnetic disk holding means 10 contacts and holds the outer peripheral end 1a of the disk 1 at three places so as not to be displaced in the radial direction of the disk due to an external impact (acceleration). By holding the contact at three places, no matter which angle an external impact is applied in parallel with the disk surface, the magnetic disk is held in contact by the magnetic disk holding means 10, so that the disk does not shift.

Referring to FIG. 3, a magnetic disk holding means 10 will be described.
Will be described in detail. In this example, the magnetic disk device is built in a personal computer. When the disk is stationary, the magnetic disk holding means 10 contacts and holds the outer peripheral end of the magnetic disk 1 (FIG. 3A),
At the start of disk rotation, the movable portion 11 of the magnetic disk holding means 10 contracts due to the voltage (power) from the personal computer 20, the magnetic disk holding means 10 is separated from the disk 1, and the magnetic disk 1 can freely rotate. Therefore, the magnetic disk holding means 10 does not hinder the rotation of the magnetic disk 1. The procedure when the magnetic disk drive starts operating will be described in further detail. From a personal computer equipped with a magnetic disk drive,
When a command to move the magnetic disk drive is received, first, (1)
(2) The magnetic disk 1 starts rotating after the movable portion 11 of the magnetic disk holding means 10 is contracted and separated from the outer peripheral edge of the disk. Conversely, when the operation is completed, that is, the operation is stopped, (3) after the magnetic disk 1 is stopped, (4) the movable portion 11 of the magnetic disk holding means 10 extends to contact and hold the outer peripheral end of the disk. Such a procedure at the time of starting operation and at the time of stopping operation may be incorporated in the drive circuit of the magnetic disk drive.

It is easy to incorporate the program of the above procedure into the drive circuit of the magnetic disk drive. Also, the power supply for driving the magnetic disk drive from the personal computer is connected to the magnetic disk holding means 10.
It can also easily be supplied to the piezo element which is the movable portion 11 of FIG.

As described above, the magnetic disk holding means 1
0 makes it possible to prevent the magnetic disk device 1 from shifting due to external impact when the magnetic disk device is not operating, so that the impact resistance performance of the device can be improved. The installation of the magnetic disk holding means 10 does not prevent the operation of the magnetic disk device. In general, a magnetic disk device is required to have a higher shock resistance during non-operation than during operation. For this reason, the magnetic disk 1 can improve the shock resistance when the magnetic disk 1 is stationary, and the magnetic disk holding means 10 of the present invention is effective in improving the shock resistance when the magnetic disk 1 is not operating.

A second embodiment will be described with reference to FIG. 4 (the movable part 11 is in a contracted state). As shown in FIG. 4 (a), the difference between the present embodiment and the first embodiment is that in the present embodiment, the tip of the movable portion 11 is provided with a wear-resistant means for preventing abrasion damage caused by contact with a disk. 13 and a contact sensor 14 for sensing contact with the disk. For example, by providing ceramic, stainless alloy, aluminum alloy, or the like provided with a carbon protective film or the like on the contact surface with the disk as the wear-resistant means 13, it is possible to prevent contact damage to the movable portion 11. Further, by providing the contact sensing sensor 14, even if the disk is elliptical or eccentric, it is possible to securely hold the disk in contact. Further, by feeding back a signal from the contact sensor 14 to control the amount of expansion and contraction of the movable part, especially when the disk is held in contact again, the movable part 11 is too extended and the disk is pressed strongly. The problem of damage can be solved. Here, as the contact sensing sensor 13, for example, a piezo element (electrostrictive element) is used, and the presence / absence of the contact is determined based on the presence / absence of the generated voltage using a voltage generated by deformation of the piezo element at the time of contact. Alternatively, FIG.
As shown in FIG. 4B as a BB cross section (in the direction of the arrow) in FIG. 4A, the contact sensor 14 can be formed by using the presence or absence of contact conduction between two points. In this case, it is necessary to form a conductive thin film 100 on the outer peripheral end of the magnetic disk 1.

As described above, also in this embodiment,
Similarly to the first embodiment, the magnetic disk holding means 10 can prevent the disk from being damaged by an external impact, improve the contact disk wear resistance of the magnetic disk holding means 10, and
The contact holding operation can be performed reliably.

A third embodiment will be described with reference to FIG. 5 (the movable part 11 is in a contracted state). The difference between this embodiment and the first embodiment is that, in this embodiment, an arc-shaped holding means 15 for reducing the contact pressure with the disk is provided at the tip of the movable portion 11. The arc-shaped holding means 15 is a magnetic disk.
It has the same curvature (circular arc) as the outer circumference of No. 1 and increases the contact area between the outer edge of the disk and the magnetic disk holding means 10, thereby reducing the contact surface pressure. This allows the first
As in the embodiment, the displacement of the magnetic disk 1 can be prevented, and the wear resistance of the contact portion can be improved.

A fourth embodiment will be described with reference to FIG. 6 (the movable part 11 is in a contracted state). FIG. 6 is a diagram viewed from the side of the magnetic disk 1. The difference between this embodiment and the first embodiment is that, in this embodiment, a U-shaped holding means 16 for restraining the vertical movement of the disk is provided at the tip of the movable portion 11. It is known that when an external impact acts on the surface of the magnetic disk 1 in the perpendicular direction (axial direction), the disk vibrates largely up and down as indicated by an arrow 101 in the figure, and as a result, the disk shifts in the radial direction. ing. 10 external shocks when not operating
In the case of 00G, for a 2.5 inch glass disk, the vertical amplitude of the disk surface is 50 μm or more. On the other hand, when the disk is rotating, it is several μm or less. For this reason, if the distance between the disk receiving surface 17 of the U-shaped holding means 16 and the disk surface (upper surface / lower surface) is, for example, 50 μm, the vertical vibration during the rotation of the disk is not hindered and the external Vertical vibration of the disk due to the impact is suppressed, and as a result, it is possible to prevent the disk from shifting in the radial direction.

A fifth embodiment will be described with reference to FIG. The difference between this embodiment and the first embodiment is that, in this embodiment, the lower surface (the base side) of the magnetic disk is held in contact.
When an external shock in the perpendicular direction (axial direction) acts on the surface of the magnetic disk 1, as described above, the disk vibrates largely up and down, and as a result, the disk shifts in the radial direction or is damaged in the worst case. It is known that there is a possibility. Therefore, at the time of non-operation, as shown in FIG. 7A, the lower surface of the disk 1 is held in contact with the movable portion 11, and at the start of operation, as shown in FIG. 7B, (1) the movable portion 11 is reduced. After that, (2) the disk 1 is rotated. Conversely, when stopping, (3)
After the rotation of the disk 1 is stopped, (4) the movable portion 11 is extended to contact and hold the magnetic disk 1. This makes it possible to supply a magnetic disk device that is particularly resistant to external shocks in the axial direction.

[0023]

As described above, according to the present invention, even when the magnetic disk drive receives an external impact when it is not operating,
Since it is possible to prevent displacement of the magnetic disk with respect to the spindle in the radial direction of the disk, it is possible to provide a highly reliable magnetic disk device that is excellent in shock resistance performance by eliminating data read / write errors due to impact. it can.

[Brief description of the drawings]

FIG. 1 is an overall configuration diagram of a magnetic disk drive according to a first embodiment of the present invention.

FIG. 2 is a sectional view taken along line AA of FIG.

FIG. 3 is a diagram illustrating the operation of the magnetic disk holding means according to the first embodiment of the present invention.

FIG. 4 is a top view showing a configuration of a magnetic disk holding means according to a second embodiment of the present invention.

FIG. 5 is a top view showing the configuration of a magnetic disk holding means according to a third embodiment of the present invention.

FIG. 6 is a top view showing a configuration of a magnetic disk holding means according to a fourth embodiment of the present invention.

FIG. 7 is an operation explanatory view of a magnetic disk holding means according to a fifth embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1-Magnetic disk 1a-Magnetic disk end face 10-Magnetic disk holding means 13-Abrasion resistance means 14-Contact sensor 15-Circular holding means 16-U-shaped holding means

Claims (10)

[Claims] 1. A magnetic disk drive comprising: a magnetic disk for recording information; and a slider on which a magnetic head for recording and reproducing information on and from the magnetic disk is provided. A magnetic disk drive, comprising: a magnetic disk holding means that is separated from the magnetic disk during rotation. 2. A magnetic disk for recording information, and a slider mounted with a magnetic head for recording and reproducing information on the surface of the magnetic disk and floating on a rotating magnetic disk surface via a fine air film. When a drive start command is issued from another device in the magnetic disk drive, the magnetic disk is separated from the magnetic disk before starting rotation, and when a drive end command is issued, the magnetic disk is A magnetic disk drive, comprising: magnetic disk holding means for holding the magnetic disk in contact after the disk stops rotating. 3. A magnetic disk for recording information, and a slider mounted with a magnetic head for recording and reproducing information on the surface of the magnetic disk and floating on a rotating magnetic disk surface via a fine air film. Means for detecting the rotation / stop of the magnetic disk based on the presence or absence of an electromotive force due to the rotation of the magnetic disk, and when a drive start command is issued from another device, the magnetic disk rotates. Move away from the magnetic disk before starting
When a drive end command is issued, the means for detecting rotation / stop of the magnetic disk includes magnetic disk holding means for contacting and holding the magnetic disk after detecting the rotation stop of the magnetic disk. Magnetic disk drive. 4. The magnetic disk drive according to claim 3, wherein said magnetic disk holding means contacts and holds an outer peripheral end of said magnetic disk when said magnetic disk is stationary. 5. A magnetic disk drive according to claim 4, wherein said magnetic disk holding means is a piezo element, a shape memory alloy, or a solenoid. 6. The magnetic disk drive according to claim 3, wherein said magnetic disk holding means contacts and holds the magnetic disk at at least three places. 7. A magnetic disk drive according to claim 6, wherein said magnetic disk holding means has a contact surface with the magnetic disk in one of an arc shape and a U-shape. 8. The magnetic disk drive according to claim 3, wherein said magnetic disk holding means contacts and holds the lower surface of the outer periphery of the disk when the magnetic disk is stationary. 9. The magnetic disk drive according to claim 3, wherein said magnetic disk holding means has wear-resistant means on a contact surface with the magnetic disk. 10. A magnetic disk drive according to claim 9, wherein said magnetic disk holding means has a contact detection sensor on a contact surface with the magnetic disk.