JPS5873076A - Air circulating system for fixed disc device - Google Patents

Abstract

PURPOSE:To block the invasion of dust to a closed chamber, by introducing air dynamic pressure caused at the surrounding section of a magnetic disc to the center of the disc positively, and keeping the pressure of a bearing section to atmospheric pressure or over. CONSTITUTION:A magnetic disc device main body 6 forms a closed chamber so as to shield a magnetic disc 1 from atmospheric pressures. The chamber is fitted with a duct 7, which has an air suction 7a around the magnetic disc 1 and an air delivery 7b around a bearing section. An air flow A is circulated through the duct 7. In rotating the magnetic disc 1, the part of air near the magnetic disc plane receives a centrifugal force to produce the air dynamic pressure around the disc. The part of the air flow enters the suction 7a, flows to the rotating center having a negative pressure, and brings the pressure to the atmospheric pressure.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a magnetic disk device used as an external storage device for a computer, and particularly relates to an air circulation system inside the device.

Conventionally, in this type of fixed disk device, the magnetic disk is mounted on a rotating shaft supported by a bearing such as a ball bearing. When the magnetic disk rotates, the air very close to the surface of the magnetic disk receives centrifugal force due to its viscosity, causing it to move in the radial direction of the magnetic disk. Therefore, the pressure is high at the periphery of the magnetic disk, and the pressure at the center of the magnetic disk is lower than atmospheric pressure, that is, negative pressure. Therefore, outside air is sucked into the magnetic disk B Flj from the bearing portion close to the center thereof. Since this outside air contains a lot of dust, this dust gets into the narrow space between the magnetic disk surface and the magnetic head, damaging the magnetic disk surface or the magnetic head, and causing a so-called head crash in the magnetic disk device. , magnetic information cannot be written on or read from the magnetic disk.

Further, some magnetic disks 8M of this type have a shielding mechanism, such as a magnetic seal using magnetic fluid, to prevent outside air from entering through the bearing portion, but they have the drawback of being expensive.

An object of the present invention is to provide a fixed disk device that can prevent the intake of outside air containing dust by raising the magnetic disk HM and the bearing portion of the magnetic disk inside to atmospheric pressure or higher than atmospheric pressure (positive pressure). .

According to the present invention, in a magnetic disk device having a fixed disk, there is provided a sealed chamber that protects the magnetic disk and the magnetic head from dust contained in the outside air, and a magnetic disk that is provided in the sealed chamber and that is generated by rotation of the magnetic disk. An air circulation system for a fixed disk device is obtained, which is characterized in that air is circulated by providing an air duct that guides air dynamic pressure in the circumferential direction to a bearing portion close to the rotation center of the magnetic disk.

Next, one embodiment of the present invention will be described in detail with reference to the drawings.

FIG. 1 shows a cross section of a fixed magnetic disk device which is an embodiment of the present invention. In FIG. 1, in the fixed magnetic disk device of this embodiment, a magnetic disk 1 is mounted on a rotating shaft 2, which is sandwiched between flanges 3a and 3b and fixed by a nut 4. The rotating shaft 2 is attached to a fixed magnetic disk device main body 6 via two bearings 5 such as ball bearings.

It is attached via a bolt or bell).

The magnetic disk device main body 6 is a sealed chamber so that the magnetic disk 1 can be shielded from the outside air. Note that this sealed chamber has a magnetic head and its positioning mechanism, but these are omitted here as they are not directly related to the present invention. Furthermore, a duct 7 is attached to the sealed chamber of the magnetic disk drive main body 6, as will be described later. The duct 7 has an air suction lower a at the periphery of the magnetic disk 1, and an air extraction lower b around a bearing near the rotation center of the magnetic disk 1. Air flow A is adapted to circulate through this duct. FIG. 2 shows a duct used in this embodiment. In FIG. 2, the duct 7 is connected to the air suction lower a
and an air extraction lower b, the air suction lower a is provided to be perpendicular to the magnetic disk surface of the peripheral portion of the magnetic disk 1, and the air suction lower a is arranged to be perpendicular to the magnetic disk surface at the peripheral portion of the magnetic disk 1, and the air suction lower a is arranged so as to suck the air flow generated by the rotation of the magnetic disk 1. The air extraction lower b has an opening larger than the diameter of the rotating shaft 2, and the air suction lower b is opened so as to transmit the air dynamic pressure generated in the air suction lower a to the air extraction [1r7b]. The lower a and the air extraction lower b are constituted by a duct body.

In the fixed magnetic disk device configured in this way, when the magnetic disk 1 rotates, the air is subjected to centrifugal force in a portion very close to the magnetic disk surface, force flows in the tangential direction of the disk, and air movement is generated around the magnetic disk. produces pressure. A portion of this air flow enters the air suction lower a of the duct 7. On the other hand, since a negative pressure is generated at the rotational center of the magnetic disk, the air having a pressure higher than atmospheric pressure that has entered the air suction lower a flows in, and the air pressure is made to be atmospheric pressure or higher than atmospheric pressure. As a result, the air pressure in the bearing portion close to the center of the magnetic disk becomes equal to or higher than the outside air, thereby preventing outside air containing dust from entering the sealed chamber of the fixed disk gK.

As explained above, the present invention actively guides the air dynamic pressure generated around the magnetic disk to the center of the magnetic disk, thereby raising the center of the magnetic disk, that is, the bearing, to atmospheric pressure or above atmospheric pressure. This has the effect of preventing dust from entering the sealed chamber.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing one embodiment of the present invention, and FIG. 2 is a perspective view showing a duct used in this example. 1,... Magnetic disk 2... Rotating shaft - 3a, 3b... 7 Lunge 4... Nut &... Bearing stock... Fixed disk device main body 7,... Dak F 7a...・Air suction port

Claims (1)

[Claims] In a magnetic disk AT having a fixed disk, there is a sealed chamber that protects the magnetic disk and magnetic head from dust contained in the outside air, and a magnetic chamber that is provided within the sealed chamber to absorb air dynamic pressure in the circumferential direction of the magnetic disk generated by rotation of the magnetic disk. An air circulation system for a fixed disk device, characterized in that an air duct is provided to guide the bearing portion close to the disk rotation center to circulate air.