JPS5975471A - Magnetic disc device - Google Patents

Abstract

PURPOSE:To attain sure turning, by extending axially a spindle shaft inserted to a center hole of a center hub with a pressing force applied to the spindle at the loading of a magnetic disc. CONSTITUTION:The constitution is adopted that the center hole 2a of the center hub 2 of the magnetic disc 1 extends the spindle shaft 3a axially by using the pressing force applied to the spindle at the loading of the magnetic disc. Thus, even if there exists more or less error in the inner diameter of the center hole of the center hub, the magnetic disc is driven surely and the interchangeability of the disc is ensured.

Description

[Detailed Description of the Invention] Technical Field The present invention relates to a magnetic disk drive, particularly a magnetic disk drive (magnetic disk drive).
This invention relates to a magnetic disk device using a magnetic disk with a center hub, such as in .

BACKGROUND OF THE INVENTION FIG. 1 shows a magnetic disk 1 housed in a conventional magnetic disk cassette. As shown in the figure, a magnetic disk 1 is a magnetic sheet disk 1 as a magnetic recording medium.
A center hub 2 made of plastic acid is attached to the center of the center hub 2, and a center hole 2a is bored in the center of the center hub 2.

Next, FIG. 2 shows a spindle 3 of a conventional magnetic disk device. The base of a spindle 3 of a conventional magnetic disk device is a disk-shaped flange 3b, and a spindle shaft 3a is provided on the upper surface of the center portion thereof. This spindle shaft 3
It is assumed that the diameter of a is slightly smaller than the inner diameter of the center hole 2a.

In order to rotationally drive the magnetic disk 1 for writing and reading information in a conventional device of this kind, a spindle 3 connected to a driving means such as a motor is connected to the center hole 2a of the center hub 2. This was done by fitting and fixing the spindle shaft 3a.

For this reason, the following disadvantages occur depending on variations in the inner diameter of the center hole and the diameter of the spindle shaft.

First, if the inner diameter of the center hole is relatively smaller than the spindle shaft diameter, it becomes difficult to insert the spindle. On the other hand, if the inner diameter of the center hole is relatively large with respect to the spindle shaft diameter, it is difficult to center the magnetic disk accurately when rotating, resulting in track misalignment, making it difficult to ensure disk compatibility. become unable to do so.

Therefore, in conventional magnetic disk drives, extremely high machining accuracy is required for the diameter of the spindle shaft, and it is also necessary to use a material that is resistant to wear for the center hub of the magnetic disk, which reduces the manufacturing cost of the entire system. This was a contributing factor to the rise.

Purpose The present invention has been made in view of the above points, and uses a simple and inexpensive structure to reliably rotate a magnetic disk even if there is some error in the inner diameter of the center hole of the center hub, and to ensure compatibility of the disks. An object of the present invention is to provide a magnetic disk device that can ensure high performance.

In order to achieve the above object, the present invention employs a configuration in which the spindle shaft that fits into the center hole of the center hub is expanded in the radial direction of the spindle using a pressing force applied to the spindle when a magnetic disk is mounted.

EXAMPLES Hereinafter, the present invention will be explained in detail based on examples shown in the drawings.

FIG. 3 shows a spindle 3 used in the magnetic disk device of the present invention. As seen in the same figure, the basic structure of the spindle 3 is the same as the conventional example shown in FIG. A groove 3a is provided. This groove 3a is the fourth
As shown in the figure, it is cut up to the flange 3b at the base of the spindle shaft 3a, and passes through the flange 3b to communicate the upper surface of the flange 3b with the F surface. Further, the spindle 3 is connected to a spindle motor shaft 5 at its lower portion.

A shaft 4a is provided at the lower portion of the collar portion 3b of each of the four grooves 3c, and a U-shaped centering arm 4 is swingably supported on this shaft 4a. Normally, when no magnetic disk is attached, the longer arm 4b of the centering arm 4 is housed in the upper part of the flange 3b of the groove 3c, and the shorter arm 4c is housed in the transparent part provided on the flange 3b. It is inserted into the hole 3d, and its tip is configured to slightly protrude above the upper surface of the collar 3b.

Next, the operation in the above configuration will be explained in detail.

First, the magnetic disk cassette is placed on the spindle 3 by known means, so that the center hub 2 of the magnetic disk (see FIG. 1), which is not shown in FIG. 4, and the axis of the spindle 3 are aligned. Next, the center hub 2 of the magnetic disk is pressed onto the spindle 3 by a hub presser indicated by reference numeral 6 in FIG.

As a result, first, the spindle shaft 3 is inserted into the center hole 2a.
a is inserted together with the arm 4b of the centering arm 4.

From this state, the center hub 2 is further pressed by the hub holder 6.
As the center hub 2 is pressed down, the lower surface of the center hub 2 pushes down the arm 4c of the centering arm 4 in the direction of arrow B in FIG. As a result, the arm 4b expands in the direction of arrow C in FIG. 4 and presses the center hole 2a diametrically outward.

If the pressing is continued from this state, the lower surface of the center hub 2 and the flange 3b of the spindle 3 will come into close contact with each other, as shown in FIG. Can be held in pressure contact.

In addition, when the lower surface of the center hub 2 and the flange 3b of the spindle 3 are in complete contact, the arm 4b presses the center hole 2a from the inside evenly in four force directions, so that the centering of the magnetic disk 1 is ensured. It is done.

As described above, even if there is some error in the inner diameter of the center hole of the center hub, the magnetic disk can be reliably held and rotated, and compatibility of the disk can be ensured. Further, since it is not necessary to maintain the machining accuracy of the spindle shaft 3a at a high level as in the conventional case, it is useful for reducing the cost of the entire apparatus.

In the above explanation, the centering arm 4 and the groove 3C are 4
Although the spindle shaft 3a is provided one by one, it goes without saying that the spindle shaft 3a may be divided into any number of equal parts, such as five or six equal parts.

Furthermore, a simple biasing means such as a leaf spring may be used to ensure that the arm 4b is housed in the groove 3C in the centering arm 4 in a prepared state in which the magnetic disk 1 is not mounted.

Effects As is clear from the above explanation, according to the present invention, the spindle shaft that fits into the center hole of the center hub is expanded in the radial direction of the spindle using the pressing force applied to the spindle when a magnetic disk is mounted. Because it uses a simple and inexpensive configuration, it is possible to reliably rotate the magnetic disk and ensure disk compatibility even if there is a slight error in the inner diameter of the center hole of the center hub. It is possible to provide an excellent magnetic disk device that can

[Brief explanation of drawings]

FIG. 1 is a perspective view showing a conventional magnetic disk, FIG. 2 is a perspective view showing a spindle of a conventional magnetic disk device, and FIG.
The following figures are for explaining the present invention: FIG. 3 is a perspective view illustrating the structure of the spindle 3 of the present invention, FIG. 4 is a partially cutaway sectional view showing the structure of the spindle of the magnetic disk device of the present invention, FIG. 5 is a partially cutaway sectional view illustrating the operation of the magnetic disk device of the present invention. 1... Magnetic disk 2... Center hub 2a
...Center hole 3...Spindle 3a...
Spindle shaft 3b...flange 3C...groove
3d...Through hole 4...Centering arm 5...Spindle motor shaft 6...Hub holder

Claims (1)

[Claims] In a magnetic disk device using a magnetic disk located behind a center hub, the spindle shaft that fits into the center hole of the center hub is configured to expand in the radial direction of the spindle using a pressing force applied to the spindle when the magnetic disk is installed. A magnetic disk device characterized by: