JPH0447918B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a magnetic disk device, and particularly to a magnetic disk device suitable for rectifying the air flow between magnetic disks to reduce vibrations of the magnetic disks. It is related to.

[Conventional technology]

In general, a magnetic disk device records and reproduces information using a magnetic disk (hereinafter referred to as a disk), which is a rotating disk, and a magnetic head that floats at submicron intervals through an air film. . The air flow between each of the plurality of disks has a non-axisymmetric velocity distribution and is a characteristic unsteady flow that swirls in the rotational direction at a speed lower than the rotational speed of the disks. As a result, the disk and the head support system of the magnetic head vibrate due to air turbulence. In some cases, these vibrations create an excessive external force on the air film between each disk and the slider supporting the magnetic head, causing contact and damage between the disk and the magnetic head.
This is called a head crash, and it is the most malicious obstacle because it destroys information.

Therefore, it is necessary to minimize air turbulence and suppress vibrations in the disk and head support system.

As a means for solving this problem, for example, there is a device described in Japanese Patent Application Laid-Open No. 154310/1983. In such a device, a flow path restricting member is provided on the outer periphery of the disk in order to suppress vibrations of the disk and head support system.

[Problem to be solved by the invention]

According to the above-mentioned conventional technology, the occurrence of turbulent flow is forcibly prevented by a flow path restricting member on the outer periphery of the disk.
Vertical vibration of the disk can be suppressed. However, in a magnetic disk device, a submicron distance must be maintained between the magnetic disk and the magnetic head, and therefore the magnetic disk must be kept free of dust at all times. This was not taken into consideration.

SUMMARY OF THE INVENTION An object of the present invention is to provide a magnetic disk device that can reduce vibrations of a magnetic disk and a magnetic head and prevent dust from adhering to the magnetic disk.

[Means to solve the problem]

The above object includes a hub fitted to a rotating shaft, a plurality of magnetic disks stacked on the outer periphery of the hub via spacers, a shroud related to a stationary structure surrounding the outer periphery of the magnetic disk, and a shroud that is supported by the shroud. and a partition member configured to be inserted between each of the magnetic disks, wherein the partition member has a cross section that generates an accelerated flow from an inner circumference to an outer circumference of the magnetic disk. This is achieved by using a triangular shaped member.

[Effect]

A cone-shaped partition member is inserted between each disk that generates an accelerated flow from the inner circumference to the outer circumference of the magnetic disk, so the pressure near the outer circumference of the disk is lower than the pressure near the inner circumference. can. As a result, vibrations of the disk and magnetic head support system due to air turbulence can be reduced, and dust adhering to the magnetic disk can be removed.

〔Example〕

Embodiments of the present invention will be described below with reference to FIGS. 1 to 3.

First, FIG. 1 is a sectional view of a magnetic disk device according to an embodiment of the present invention, and FIG. 2 is a partially sectional perspective view showing a partition member in the device of FIG.

In FIG. 1, 1 is a magnetic disk (hereinafter referred to as a disk), 2 is a ring-shaped spacer, 3 is a hub, 4 is a bearing, and 5 is a rotating shaft. That is,
A plurality of disks 1 are stacked alternately with spacers 2 and fixed to a hub 3. The hub 3 is fitted onto a rotating shaft 5 supported by a bearing 4, and is rotationally driven.

6 is a shroud related to a stationary structure that surrounds the outer periphery of the plurality of disks 1. The cylindrical shroud 6 is fixed to the base 7 at a constant distance from the outer periphery of the disk 1.

Reference numeral 8 denotes a donut-shaped partition disk formed so as to have a tapered portion 8a having a triangular cross section for a plurality of partition members supported by the shroud 6, and is inserted between each disk of the plurality of disks 1. .

Figure 2 shows the structure of the shroud 6 and the partition disc 8, and the dashed line in the diagram shows the disc 1.
It is.

Next, the flow of air between each disk of the magnetic disk device in this embodiment will be explained.

When the disk 1 rotates as the rotary shaft 5 rotates, the air on the surface of the disk rotates and tends to flow outward due to centrifugal force. The distance between each disk of the disk 1 is narrowed by the partition disk 8, and an accelerated flow is generated from the inner circumference to the outer circumference of the rotating disk 1. At this time, the pressure near the outer periphery of the disk 1 is lower than that near the inner periphery, and the flow between the disks is controlled by the rotating disk 1.
The flow follows concentric circles. Therefore, the eddy turbulence near the wall surface that occurs when the conventional shroud described above is added is less likely to occur, and the flow between the disks can be rectified into a concentric flow. Further, since the partition member 8 has a taper 8a, it has a unique effect of being less likely to attract dust. Therefore, it is possible to prevent dust from adhering to the magnetic disk.

The effect of the above example was evaluated based on the experimental results.
This will be explained with reference to the figures.

Figure 3 is a spectral diagram of disk vibration displacement in a comparative experiment between the magnetic disk device shown in Figure 1 and the conventional technology, where the horizontal axis represents frequency f (Hz) and the vertical axis represents disk vibration displacement Y (μm). A conventional magnetic disk device with a shroud is shown by a dashed line, one without a shroud is shown by a broken line, and a conventional magnetic disk device with a shroud and a partition member is shown by a solid line. M indicates the vibration mode of the disk.

In the magnetic disk devices used in these comparison experiments, the vertical vibration displacement of a disk with a diameter of 8.8 inches was measured from the stationary side using a displacement sensor at a rotation speed of 3600 rpm, and frequency analysis was performed. The figure shows a connection of peak values of spectra obtained by frequency analysis.

In general, the vertical vibration of the disk 1 includes an initial runout component caused by machining and disk tightening, a vibration response component due to external structural force transmitted from the rotating shaft 5 system, and a flow rate caused by air turbulence between each disk. Contains vibration response components due to physical strength. In the frequency range of 0 to 400 Hz, the runout component is the main component, but in the frequency range of 400 to 1000 Hz, the vibration response component due to the fluid force is the main component.

In this example, compared to the conventional technology,
Low vibration response in the frequency range of 400-1000Hz.
Vibration reduction is approximately 10% compared to the case with only the shroud, and approximately 20% compared to the case without the shroud.

From this, it can be seen that in this example, the flow between the disks was rectified, and the turbulent fluid force acting on the disk 1 was reduced compared to the conventional one.

As described above, according to this embodiment, the fluid force acting on the disk 1 is reduced by rectifying the flow between the disks, and the vibration of the disk 1 can be reduced. Further, by inserting the partition disk 8 between each disk, vibration interference between the disks through the air can be prevented, and the movement of the disk 1 can be reduced.

Therefore, vibrations of the disk 1 and the magnetic head support system (not shown) can be reduced, and head crash can be prevented.

Further, according to this embodiment, it is possible to prevent dust from adhering to the magnetic disk.

In the above embodiments, an example of a shroud was described as a stationary structure, but the present invention is not limited to a shroud, but may be applied to other stationary structures such as a cover.

〔Effect of the invention〕

According to the present invention, by rectifying the air flow between the respective disks as the plurality of magnetic disks rotate, vibrations caused by air turbulence in the magnetic disks and magnetic head support system can be reduced, and magnetic This also helps prevent dust from adhering to the disk.

[Brief explanation of the drawing]

1 is a sectional view of a magnetic disk device according to an embodiment of the present invention, FIG. 2 is a partially sectional perspective view showing a main part of a partition member in the device of FIG. 1, and FIG.
The figure is a spectral diagram of disk vibration displacement in a comparative experiment between the magnetic disk device of FIG. 1 and that of the prior art. 1...Magnetic disk, 2...Spacer, 3...
Hub, 5... Rotating shaft, 6... Shroud, 8...
Partition disk, 8a...tapered part.

Claims (1)

[Claims] 1. A hub fitted to a rotating shaft, a plurality of magnetic disks stacked on the outer periphery of the hub via spacers, a shroud related to a stationary structure surrounding the outer periphery of the magnetic disk, and a In a magnetic disk device comprising a partition member configured to be inserted between each of the magnetic disks, the partition member has a triangular cross section that generates an accelerated flow from the inner circumference to the outer circumference of the magnetic disk. A magnetic disk device characterized in that it is a member having the following characteristics.