JPH05258437A - Spindle structure of magnetic disk device - Google Patents

Abstract

PURPOSE:To enhance the accuracy of rotation of a magnetic disk and to easily reduce the thickness of the device by freely turnably supporting a spindle hub fixed with the magnetic disk to a fixing shaft erected on a base. CONSTITUTION:A pair of ball bearings 4 are fixed to the fixing shaft 15 erected on the base 11. The positioning part of the magnetic disk 3 is then formed on the outer peripheral surface and the housing part 16a of the spindle hub 16 formed with an internal thread part at the center is fitted into the above- mentioned ball bearings 4. The external thread part of a clamping bolt 18 is then screwed into this internal thread part, by which the magnetic disk 3 is fixed via a clamping plate 17 to the spindle hub 16. The high-speed rotation is, therefore, executed with the high accuracy and the thickness is reduced while the construction is extremely simple.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a spindle structure of a magnetic disk device widely used as an external storage device for various computers.

In recent years, the storage density of the magnetic disk device has been remarkably improved at a rate of 10 times or more in 10 years, and the miniaturization of the device has been remarkably progressed against the background of this high recording density. Recently, the disk size has been reduced from 5 inches to 3.5 inches, and further down to 2.5 inches.

In the process of miniaturization as described above, thinning is more strongly demanded, and since the spindle mechanism in which rotation accuracy is important is a bottleneck in thinning, this rotation accuracy is required. There is a need for a spindle structure for a magnetic disk drive that can be secured and can be easily thinned.

[0004]

2. Description of the Related Art As shown in FIG. 5, a spindle structure of a magnetic disk device which has been widely used in the past has a size such that the inside of the magnetic disk device can be hermetically sealed by covering a cover 2 with two ball bearings in the central portion. Into the base 1 on which the cylindrical housing portion 1a for inserting 4 is projected, two ball bearings 4 which support the high speed rotation are inserted into the inside of the housing portion 1a at regular intervals to fix the outer ring, A base portion is constructed by fixing a cylindrical stator coil 9-2 that rotationally drives a spindle hub 6 described later on the outer peripheral surface of the housing portion 1a.

Further, a step portion for holding the magnetic disk 3 is provided on one end side of a cylinder made of a light metal which fits the magnetic disk 3 on the outer peripheral surface to position the center position and fixes the rotor magnet 9-1 on the inner diameter. With respect to the height of the housing portion 1a, the spindle hub 6 is provided on the outer peripheral surface, the inner diameter of the other end surface side is closed, and a through hole is formed in the center, and an outer diameter that allows the inner ring of the ball bearing 4 to be statically fitted. A rotary drive unit in which the inner diameter of the rotary shaft 5 having a slightly long rigidity is closed and press-fitted into the through hole, and a cylindrical rotor magnet 9-1 is fixed to a position on the inner surface of the cylinder facing the stator coil 9-2 is provided. Be built.

Then, two magnetic disks 3 are attached to the spindle hub 6 of the rotary drive unit, for example, via a spacer 3-1.
Is inserted into the outer peripheral surface, and the disk-shaped clamp plate 7 is press-fitted into the spindle hub 6. And the two magnetic disks 3 and the clamp plate 7 are coupled to each other, and the rotary shaft 5 is inserted into the inner ring of the ball bearing 4 fixed inside the housing portion 1a of the base 1 to cover the cover 2 with the stator coil. The spindle hub 6 connected to the magnetic disk 3 is rotated at high speed by applying a current to 9-2.

[0007]

A problem with the spindle structure of the conventional magnetic disk device described above is that the rotary shaft is located on the center line of the spindle hub 6 having the magnetic disk 3 fitted on the outer peripheral surface as shown in FIG. Since the magnetic disk 3 is fixed by projecting 5 toward the base 1 and fastening the clamp plate 7 to the end surface of the cover 2 of the rotating shaft 5 with the bolt 8, the height of the rotating body increases.

A rotary shaft 5 projecting from the spindle hub 6 is molded on a base 1 to form a housing portion 2a inside the housing 2a.
Since it is inserted into the individual ball bearings 4, the spindle hub 6 is rotatably supported by the cantilevered rotary shaft 5, and the two ball bearings are used to ensure the rotation accuracy of the magnetic disk 3. There is a problem that the thinning of the device is hindered because the interval of 4 is required to be large, that is, the height of the housing portion 1a cannot be reduced.

Further, in order to reduce the thickness, a spindle structure for rotating the outer ring of the ball bearing 4 is more preferable. However, in this outer ring rotating structure, a bolt 8 for fastening the clamp plate 7 is provided at the center. There is a problem that it cannot be installed.

In view of the above problems, the present invention rotatably supports a spindle hub having a magnetic disk fixed to a fixed shaft erected on a base so that the magnetic disk can be rotated with high accuracy. It is an object of the present invention to provide a spindle structure of a magnetic disk device that facilitates thinning of a magnetic disk device.

[0011]

According to the present invention, as shown in FIG. 1, a fixed shaft 15 which holds a ball bearing 4 and stands upright on the inner surface of a base 11, and a holding portion which positions a magnetic disk 3 on the outer peripheral surface thereof. And a housing portion 16a for accommodating the outer ring of the ball bearing 4 is provided at the center so as to project.
A spindle hub 16 having a fastening portion formed on the periphery thereof, a clamp plate 17 having a fastening hole in the center for holding the magnetic disk 3 therein, and a central hole being bored to connect with the fastening portion of the spindle hub 16. And a clamp bolt 18 formed with a means for forming the clamping bolt 18, and the housing portion 16a of the spindle hub 16 is fitted into the ball bearing 4 of the fixed shaft 15 which is erected on the base 11 and the clamp bolt 18 is attached to the fastening portion. By screwing in, the magnetic disk 3 is fixed to the spindle hub 16 via the clamp plate 17.

[0012]

In the present invention, the magnetic disk 3 is attached to the spindle hub.
The magnetic disk 3 can be fixed by fitting it onto the outer peripheral surface of 16 and screwing the clamp bolt 18 into the female screw portion via the clamp plate 17, and the housing portion of the spindle hub 16 can be fixed.
The pair of ball bearings 4 is housed in 16a, and the inner ring of which is fitted to the fixed shaft 15 which is erected on the inner surface of the base 11 and fixed, thereby rotating the magnetic disk 3 with high precision and thinning the device. Is possible.

[0013]

Embodiments of the present invention will be described in detail below with reference to FIGS. 1 is a schematic side sectional view showing a spindle structure of a magnetic disk device according to a first embodiment of the present invention, FIG. 2 is an enlarged perspective view showing a clamp bolt of this embodiment, and FIG.
Shows a schematic side sectional view showing the second embodiment, and FIG. 4 shows a schematic side sectional view of the third embodiment. In the figure, the same members as those in FIG. 11 is the base of the magnetic disk device, 15 is a fixed shaft that is the center of rotation of the magnetic disk, 16 is a spindle hub that holds the rotation of the magnetic disk, 17 is a clamp plate for connecting the spindle hub and the magnetic disk, and 18 is It is a clamp bolt for joining.

The base 11 is formed so that a fixed shaft 15, which will be described later, can be erected on a flat plate having a size capable of sealing the inside of the magnetic disk device when the cover 2 is attached. As shown in FIG. 1, the fixed shaft 15 has an outer diameter that fits in the inner ring of the ball bearing 4 and has a length equal to the distance between the base 11 and the cover 2. The base 11 and the cover 2 are provided with upright means (not shown) that is fixed vertically to the inner surfaces of the cover.

As shown in FIG. 1, the spindle hub 16 has the above-mentioned fixed shaft 15 at the center of a disk formed with a stepped portion for inserting the center hole of the magnetic disk 3 into its outer peripheral edge for positioning and clamping.
A cylindrical housing part 16a into which the outer ring of the ball bearing 4 fitted in the can be fixed can be projected concentrically with the stepped part, and a female screw is screwed into the inner surface of the ring-shaped groove formed on the outside of the housing part 16a. Grooves are formed on the surface facing the base 11 to fix the rotor magnet 19-1.

The clamp plate 17 is a disc having a diameter substantially equal to the outer diameter of the portion of the spindle hub 16 that holds the magnetic disc 3, and a ring-shaped projection for pressing the magnetic disc 3 is formed on the outer peripheral edge of the disc. The female hub portion of the spindle hub 16 has a through hole with a slightly larger inner diameter formed in the center of the center to provide rigidity.

As shown in FIG. 1, the clamp bolt 18 is inserted into the through hole of the clamp plate 17 and is screwed into the female threaded portion of the spindle hub 16, so that the peripheral edge of the through hole is directed toward the spindle hub 16. As shown in FIG. 2, an inner diameter into which the housing portion 16a of the spindle hub 16 can be fitted and a male screw portion 18c into which the female portion of the spindle hub 16 can be screwed so as to be pressed.
A flange 18b having an outer diameter capable of pressing the peripheral edge of the through hole of the clamp plate 17 is formed on one end of the molded cylinder, and a slit 18d for tightening and rotating is formed on the end face.

The first embodiment of the spindle structure of the magnetic disk device using the above members is a base 11 having a stator coil 19-2 fixed to a position corresponding to the rotor magnet 19-1 of the spindle hub 16 as shown in FIG. In addition, the fixed shaft 15 is provided with a flat stator coil by a standing means (not shown).
Stand vertically on the inner surface to which 19-2 is fixed.

Further, the housing portion 16 of the spindle hub 16
Two ball bearings 4 are inserted into a at a fixed interval to fix the outer ring, and the flat rotor magnet 19-1 is fixed to the groove formed on the surface facing the base 11 with an adhesive and the outer peripheral Insert the magnetic disk 3 in steps and clamp plate
The rotating body is constructed by inserting the male screw portion of the clamp bolt 18 into the through hole of 17 and screwing and tightening the female screw of the spindle hub 16.

Then, the inner ring of the ball bearing 4 fixed to the spindle hub 16 is fitted into the fixed shaft 15 provided upright on the inner surface of the base 11 and the cover 2 is crowned, so that the base 11 and the cover 2 are separated from each other. The spindle hub 16 coupled to the magnetic disk 3 is housed in the space, and the spindle hub 16 is configured to rotate at high speed by applying a current to the stator coil 19-2.

As a result, the magnetic disk 3 fitted on the outer peripheral portion of the spindle hub 16 can be fixed by screwing the clamp bolt 18 into the female screw portion of the spindle hub 16 through the clamp plate 17, and the housing portion 16a of the spindle hub 16 can be fixed. A fixed shaft in which a pair of housed ball bearings 4 are erected on the inner surface of the base 11.
Since it is fitted in 15, the magnetic disk 3 can rotate with high accuracy and the device can be easily thinned.

Next, as a second embodiment, as shown in FIG. 3, the magnetic disk 3 is fitted into the outer peripheral edge of the housing for positioning and clamping, and the outer peripheral surface is threaded with a male screw.
On the spindle hub 26 having the ball bearing 4 fixed to a and the rotor magnet 19-1 fixed thereto, a clamp bolt 28 having a female hole for screwing with the male screw in its center hole is provided with a clamp plate similar to that of the first embodiment. By inserting the clamp bolt 28 into the through hole of 17 and screwing and tightening the clamp bolt 28 into the male screw of the spindle hub 26, a rotary body similar to the above is constructed.

Further, in the third embodiment, as shown in FIG. 4, a housing portion 36a protruding from a disk-shaped center having an end attaching portion for inserting and positioning and sandwiching the magnetic disk 3 on the outer peripheral edge thereof.
A female screw portion is formed on the inner diameter of the cover 2 side and the clamp plate is provided with a clamp bolt 38 having a male screw screwed to the female screw portion.
The same effect as in the first embodiment is obtained by tightening 17 and fixing the ball bearing 4 provided in the housing portion 36a and sandwiching the magnetic disk 3 at the same time.

[0024]

As is apparent from the above description, according to the present invention, there are advantages such that the rotation of the magnetic disk is highly accurate and the device can be easily thinned according to the present invention. Therefore, it is possible to provide a spindle structure of a magnetic disk device that is expected to have the effect of improving the reliability and reliability.

[Brief description of drawings]

FIG. 1 is a schematic side sectional view showing a spindle structure of a magnetic disk device according to a first embodiment of the present invention.

FIG. 2 is an enlarged perspective view showing a clamp bolt of this embodiment.

FIG. 3 is a schematic side sectional view showing a second embodiment.

FIG. 4 is a schematic side sectional view showing a third embodiment.

FIG. 5 is a schematic side sectional view showing a spindle structure of a conventional magnetic disk device.

[Explanation of symbols]

2 is a cover, 3 is a magnetic disk, 4 is a ball bearing, 11 is a base, 15 is a fixed shaft, 16, 26, 36 are spindle hubs, 16a, 26a, 36
a is a housing part, 17, is a clamp plate, 18, 28, 38 is a clamp bolt, 18a is a central hole, 18b is a flange part, 18c is a male screw part, 18d is a slit, 19-1 is a rotor magnet, 19-2 is 19-2. Stator coil,

Claims (2)

[Claims] 1. A spindle for rotatably supporting a magnetic disk, comprising a fixed shaft (15) which holds a ball bearing (4) and stands on an inner surface of a base (11), and a magnetic disk (3) on an outer peripheral surface. The housing part (16a) for molding the nipping part for positioning and housing the outer ring of the ball bearing (4) is provided at the center so that the housing part (16a)
A spindle hub (16) having a fastening portion formed on the periphery, a clamp plate (17) having a fastening hole in the center to hold the magnetic disk (3), and a spindle hole (16) having a center hole. ) Of the spindle hub (16) on the ball bearing (4) of the fixed shaft (15) standing on the base (11). The magnetic disk is inserted through the clamp plate (17) by inserting the housing portion (16a) and screwing the clamp bolt (18) into the fastening portion.
A spindle structure for a magnetic disk drive, wherein (3) is fixed to the spindle hub (16). 2. The ball bearing has a lower end portion of the clamp bolt.
2. The spindle structure for a magnetic disk drive according to claim 1, wherein the outer ring of (4) is pressed down.