JPS6260748B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement in a magnetic disk device, particularly a device having a swing type mechanism for randomly accessing an information read/write head, and more specifically, to an improvement in a device having a swing type positioner for accessing a magnetic head. By installing the motor consisting of a rotor and a stator, which is the driving part of the positioning arm, outside the disk enclosure and completely sealing it from the inside air inside the enclosure, the motor The present invention relates to a magnetic disk device that prevents the disk and magnetic head from being adversely affected by the heat and dust generated by the disk drive.

In conventional magnetic disk devices using a swing-type positioner, a drive unit such as a voice coil motor is installed inside the disk housing, and the heat generated by the motor causes the temperature of the air inside the housing to rise, causing thermal damage. There is a disadvantage that off-track (positional deviation between the position signal head and the data read/write head due to thermal expansion) increases. Furthermore, when the windings and winding frame of the motor, which is the drive unit, become hot, volatile substances are generated, which can cause serious accidents such as head crashes. This type of defect is a serious problem, especially in closed-type devices, and becomes particularly noticeable when high-speed access is to be achieved.

FIG. 1 shows a sectional view of a swing type magnetic disk device according to the prior art. In the figure, 1 is a magnetic disk, 2 is a hub, and a spindle 3 is supported via a bearing 6 on a base 5 of a device housing (or enclosure or storage body). The arm 6 for the magnetic head supports the magnetic head 7 at one end, and the rear end (right side in the figure)
A movable element 9 and a stator 10 of a motor 11 are attached to the motor. The arm 6 is swung horizontally in the figure by a swiveling shaft 8 to access any information track. The swing shaft 8 and the motor 11 constitute an actuator (operating section) of the magnetic disk device.

Information tracks are concentrically placed on magnetic disk 1.
They are provided at a pitch of 25.4 μm. Here, assume that alignment is performed using the head 7' of the lowest arm 6' in the figure. 1℃ above and below the air inside the storage room
Suppose there is a temperature difference of The arm is generally made of aluminum, and the thermal expansion of aluminum is 23μ
m/m°C, the uppermost arm 6 in the figure has a positional deviation of 2.3 μm per 10 cm of its length. This means that in the relative relationship between the magnetic head and the information track, the head 7' of the alignment arm 6' and the head 7 of the arm 6, which has a temperature difference of 1°C, have a deviation of 2.3 μm per 10 cm of arm length. Therefore, the head 7 is deviated from the information track by 2.3 μm from its proper position, or about 10% of the pitch of the information track.

On the other hand, the magnetic head 7 is designed to float by 0.2 to 0.5 .mu.m due to the air that enters between the head and the disk when the disk 1 rotates. If dirt with a diameter of 1 μm were to get between the head and the disk, the head would no longer function. Therefore, the inside of the container is designed so that there is no dust with a diameter of 0.3 μm or more.

Since magnetic disks are of the type described above, the problems of temperature and dust inside the disk housing are extremely important. Incidentally, the temperature rise inside the storage body depends on the frictional heat between the disk and the air when the disk rotates and the heat generated by the motor in approximately equal proportions. Furthermore, as mentioned above, motors are a source of volatile substances.

The inventor of the present application believes that frictional heat due to the contact between the disk and the air is unavoidable and is generated almost uniformly within the housing, but the heat generated by the motor is localized, and that it is caused by the magnetic head and information We focused on this point, which is the main cause of misalignment between the track and the track.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to solve the above-mentioned problems in conventional magnetic disk devices, and as a means for achieving the object, a motor, which is a drive section of an arm for a magnetic head, is housed in a magnetic disk drive. By installing it outside the body and completely sealing the motor with the air inside the housing, it is ensured that the heat and dust generated by the motor do not have an adverse effect on the disk and magnetic head.

Embodiments of the magnetic disk device of the present invention will be described below with reference to the accompanying drawings.

FIG. 2 shows a cross section of the main part of the magnetic disk device according to the present invention, that is, the operating part (actuator). Therefore, the spindle portion in FIG. 1 has been omitted. The illustrated device is the operating part of a rocking type disk device, and in the figure, 11 is a rocking arm, 12 is a rocking shaft, 13 is a bearing, 14 is a base of a disk storage body (hamming or enclosure), and 15 1 is a magnetic seal, 18 is a drive section (vocal coil motor), and 16 and 17 are a movable element and a stator of the drive section, respectively.

A magnetic head as shown in FIG. 1 is attached to the tip of the swinging arm 11, and is used to trace any information track on a disk (not shown).
do. The swinging arm 11 is attached to a swinging shaft 12, and one end (lower end in the figure) of the swinging shaft 12 extends outside the base 14, and the movable element 16 of the drive unit 18 is attached to the tip thereof. connected. The swing shaft 12 and the drive section 18 thus constitute the operating section (actuator) of the device. The air inside the housing is completely sealed by the magnetic fluid seal 15, and the adverse effects of heat and dust from the drive section 18 do not enter the inside air. Note that the drive section 18 consumes a considerable amount of power in response to the recent increase in speed of magnetic disk devices, and generates a considerable amount of heat.

Magnetic fluid seal 15 is formed by conventional techniques. That is, a ring made of ferromagnetic material is arranged around the swing shaft 13, a magnet is arranged between the rings, and the contact area between the ferromagnetic ring and the magnet and the swing shaft contains fine iron powder. The magnetic fluid is trapped.

Since the disk storage body is completely sealed, a paper filter is placed approximately in the center of the upper cover of the disk storage body in order to cope with the air expansion due to the frictional heat generated by the contact between the disk and the air. Since such a filter is obvious to those skilled in the art, it is not shown and detailed description thereof will be omitted. Such a filter allows air to flow between the disk housing and the outside air while preventing dust from entering the housing.

FIG. 3 shows a main part of another embodiment of the present invention in cross section. In the figure, 21 is a swing arm;
22 is a swing shaft, 23 is a bearing, 24 is an enclosure base, 25 is a magnetic seal, 28 is a drive section, 26 is a movable element, and 27 is a stator.

In the illustrated embodiment, the swing shaft 22 is attached to the outer ring of a bearing 23. For this purpose, a fixed shaft 29 is provided, which is fixed by two support rods 30. Such devices are suitable for high speed operation. In this embodiment as well, the inside of the disk storage body is protected from heat and dust generated by the drive unit 28 in the same way as in the embodiment shown in FIG.

As explained above, in the magnetic disk device according to the present invention, the heat generated inside the disk housing (enclosure) is reduced to about half compared to the heat in the conventional example, and the The generated dust is kept outside the enclosure and does not enter the enclosure.
The magnetic disk device can be operated at high speed, and dust is prevented from entering between the magnetic head and the disk, increasing reliability in the operation of the device.

[Brief explanation of the drawing]

FIG. 1 is a schematic sectional view of a conventional magnetic disk device, and FIGS. 2 and 3 are schematic sectional views of an embodiment of the present invention. 11, 21... Swing arm, 12, 22... Swing shaft, 13, 23... Bearing, 14, 24...
...Base, 15, 25...Magnetic seal, 16, 26
...Mover, 17, 27...Stator, 18, 28
... Drive unit, 29 ... Fixed shaft, 30 ... Support rod.

Claims (1)

[Claims] 1 Contains at least one magnetic disk, a spindle for rotating the magnetic disk, a magnetic head for reading and writing information, an oscillating motion unit for accessing this magnetic head to any information track, and these parts. In a magnetic disk device consisting of a storage body, a swing shaft constituting the operating unit extends outside the storage body, a drive unit is attached to the tip of the swing shaft, and a link between the swing shaft and the storage body is provided. A magnetic disk device characterized in that the space between the base and the base is sealed by a magnetic fluid seal.