JPH011176A - Disk and hub centering device for magnetic disk drives - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a magnetic disk drive (magnetic disk drive device), and more particularly to a structure for attaching a magnetic recording disk to a rotating hub.

A disk drive that magnetically records data has a plurality of rotatable hubs mounted at intervals. As the disk rotates on the hub, a pickup moves across the surface of the disk, recording and reading digital data from concentric tracks on a magnetic film on the surface of the disk.

In order to reduce the overall size of the disk drive,
The spindle motor that rotates the hub is located inside the hub rather than outside the hub. Therefore, it was necessary to provide a magnetic flux return path and provide insulation between the spindle motor and the recording disk, and to use ferromagnetic steel as the material for the hub.

Because the disks are made of glass or aluminum, alignment problems arise when the disk drive is subjected to cycling changes in temperature. For example, depending on the conditions at the shipping destination, the temperature may drop to -40° C. At this temperature, the disk contracts at a different rate and amount than the hub, causing interference between the disk and the hub. Such interference causes the disk to slip on the hub, creating a new center of rotation for the disk, which can result in off-track errors in recorded data (recording and reading on different trunks). error).

In the past, various attempts have been made to eliminate disc slippage due to temperature cycling, such as reducing the diameter of the hub and placing strips of Teflon tape parallel to the axis of the hub and on the surface of the hub. Some are installed at radial intervals. The tape is supported to provide sufficient centering of the disk as it moves relative to the hub. However, this method has the disadvantage of being difficult and time consuming to assemble, as well as a loss of authenticity if the tape is peeled off the top surface of the hub by the disc. There is also the problem that the disk gets dirty as it slides down the entire length of the tape during assembly.

SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide an apparatus capable of centering a disk on a disk drive hub and maintaining the radial alignment of the disk relative to the hub in the event of cyclic changes in temperature. .

A feature of the invention is a disc spacer ring insert with centering fingers used to align the discs.

Another feature of the invention resides in the insert of the spacer ring with a cavity capable of receiving the centering finger in case the centering finger is bent during assembly of the disk on the spindle.

The above objects and features of the present invention will become apparent from the following detailed description of embodiments of the present invention, which are explained in conjunction with the accompanying drawings.

FIG. 1 is an exploded view showing the general structure of a hub 10 and disk assembly for a magnetic disk drive. In this way, two disks 12 are attached to the hub 10, and a spacer 14 is interposed between the disks 12, so that the pickup head can freely move between the disks 12. As mentioned before, hub IO
A spindle motor for driving the disk 12 attached to the hub IO is arranged within the hub 10 as indicated by the dotted line number 16. Therefore, to provide a return path for the magnetic flux and to facilitate magnetic isolation between the spindle motor 16 and the recording disk 12, the hub 10 must be made of a ferromagnetic material such as steel. Must not be.

As previously mentioned, alignment of the disks on the hub becomes an issue when the disk drive is subject to cycling changes in temperature. The alignment of disk 12 with respect to hub 10 is schematically illustrated in FIGS. 2A-2D. FIG. 2A shows the disk 12 as it is initially assembled into the hub 10. The tracks of the disk 12 for recording data are thus set at the hub 10.
It is formed based on the rotation axis of the disk 12 assembled in the.

Depending on the conditions of the shipping destination, when the disk 12 is subjected to a cyclical change in temperature of up to 140 degrees Celsius, the disk 12
It contracts at a rate and amount of contraction different from zero, which causes interference as shown in FIG. 2B. Due to such interference, the disk 12 is pushed away from the hub l as shown by the arrow.
Slip on O. When such slippage of the disk 12 occurs, the axis of rotation of the disk changes as shown in FIGS. 2C and 2D. FIGS. 2C and 2D show the arrangement of the hub 10 and the disk 12 after slipping at low temperatures and at normal temperatures, respectively. The new axis of rotation thus created causes off-track errors when reading and recording data.

FIG. 3 shows a spacer ring 26 according to one embodiment of the invention.
and a spacer ring insert 28. FIG. The outer diameter of the insert 28 is smaller than the inner diameter of the spacer ring 26, so that the insert 28 is smaller than the inner diameter of the spacer ring 26.
It can be installed within 6. Insert 28 is preferably made of a pliable material, such as injection molded plastic. insert 28
has a plurality of centering fingers 30.

Each centering finger 30 extends from above to below the insert 28 and is configured to provide positioning between the spindle hub and the disk as shown in FIG. As shown in FIG. 4, a plurality of disks 32
are mounted on a hub 34, and each disc 32 is spaced apart from each other by a spacer ring 26 and a spacer ring insert 28. Centering fingers 30 of insert 28 are disposed between disk 32 and hub 34 and extend a length less than or equal to two thicknesses of disk 32. These centering fingers 30 therefore center the disc 32 on the hub 34 and, because the centering fingers 30 are pliable, retain the disc 32 movably relative to the hub 34 during cycling of temperature. are doing.

According to another feature of the invention, the insert 28 is provided with a cavity 38 capable of receiving the centering finger 32 in the event that the centering finger 32 should be bent during the assembly operation of the disc.

Since the depth of the fingers 30 is less than two times the thickness of the disk 32, even if one of the disk spacers is tilted, the other spacers are not affected.

One advantage of using the spacer ring insert 28 of the present invention is that the symmetrical construction of the insert 28 eliminates the need for balancing.

By using the spacer ring insert of the present invention, radial alignment of the disk relative to the hub can be easily maintained during cycling of temperature. Although the present invention has been described above based on specific embodiments, the described embodiments are illustrative and do not limit the scope of the present invention. .

[Brief explanation of drawings]

FIG. 1 is an exploded view showing a hub and disk assembly of a magnetic disk drive. Figures 2A, 2B, 2C and 2D illustrate disk slippage due to cyclic changes in temperature. FIG. 3 is an exploded view of a spacer ring and spacer ring insert according to one embodiment of the invention. FIG. 4 is a sectional view showing the spacer ring and spacer ring insert of FIG. 3 attached to a hub. 26... Spacer ring, 28... Spacer ring insert, 30... Centering finger, 32...
...Disk, 34...Hub, 28...Cavity.

Claims (1)

[Scope of Claims] (1) In an insert used in combination with a disk spacer for attaching a magnetic disk to a rotating hub of a disk drive, a main body portion having a height equal to the height of the spacer; a plurality of finger portions projecting a length less than one-half the thickness of the disk, the finger portions separating the disk from the hub and retaining the hub during temperature cycling; An insert characterized in that it holds a disc so that it can move against it. (2) The insert according to claim 1, wherein the body portion is provided with a plurality of cavities for receiving bent fingers. (3) 1/1/2 of the thickness of the disk downward from the main body portion.
3. An insert according to claim 2, further comprising a plurality of finger portions projecting by a length of no more than 2. 4. The insert of claim 3, wherein the body portion and the plurality of finger portions are formed from injection molded plastic. (5) A disk drive assembly comprising a hub, a plurality of disks assembled to the hub, a spacer ring disposed between adjacent disks, and an insert for each spacer ring, wherein the insert is a part of the spacer. a first plurality of finger portions projecting upwardly from the body portion by a length not more than one-half the thickness of the disk; and downwardly from the body portion; , a second plurality of finger portions projecting a length less than or equal to one-half the thickness of the disk, the finger portions separating the disk from the hub;
and a disk drive assembly movably retaining the disk relative to the hub during temperature cycling. (6) Each of the inserts has a plurality of cavities in its body portion, each of which is adapted to receive a folded finger portion therein. Disk drive assembly as described in. 7. The disk drive assembly of claim 6, wherein the insert is formed from injection molded plastic.