JPH0737310A - Magnetic disk device - Google Patents

Abstract

PURPOSE:To laminate and fix a plurality of magnetic disk media to a spindle motor without generating warpage and distortion by arranging a shim having a line-contactable shape between a flange section and a magnetic disk medium. CONSTITUTION:An annular shim 7 having a line-contactable shape is disposed between the flange section 5 of a spindle motor l and a magnetic disk medium 2. The shim 7 is brought into line-contact at a position determined by the medium 2 and the inside diameter of the shin 7, and the medium 2 is not subject to an effect even when the flange section 5 is deflected by the clamping force of a clamp rin 4. Accordingly, a plurality of medium 2 can be laminated and supported horizontally at all times regardless of the deflection of the flange section 5. It is favorable that the sectional shape of the shim 7 is formed into a rectangular triangular or circular shape.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic disk device used in an information processing apparatus, etc. The present invention relates to a magnetic disk device that prevents distortion or warpage.

[0002]

2. Description of the Related Art Referring to FIG. 6, a conventional magnetic disk device of this type has a spindle motor 10 provided with an annular flange portion 50 having a medium supporting surface 60 at the bottom thereof, and is laminated and fixed to the spindle motor 10. A plurality of magnetic disk media 20, a plurality of spacer rings 30 mounted between the plurality of magnetic disk media, and a plurality of magnetic disk media 20 alternately stacked on the spindle motor 10.
And a clamp ring 40 which is clamped and fixed from the upper portion of the spindle motor 10 so as to hold and fix the plurality of spacer rings 30 (hereinafter, referred to as first prior art).

Now, the operation of incorporating a plurality of magnetic disk media 20 into the spindle motor 10 will be described.

First, the inner diameter portion of the magnetic disk medium 20 is inserted along the cylindrical surface of the spindle motor 10 to insert the magnetic disk medium 20 into the medium supporting surface 60 of the flange portion 50.
Contact.

Next, the spacer ring 30 is inserted into the spindle motor 10 in the same manner as the magnetic disk medium 20 and brought into contact with the magnetic disk medium 20.

After the above operation is repeated to stack a desired number of magnetic disk media 20 on the spindle motor 10, the clamp ring 40 is fastened and fixed to the upper portion of the spindle motor 10 by a fastening means (not shown) such as a screw.

The clamp ring 40 has an elastic structure, and holds and fixes the magnetic disk medium 20 and the spacer ring 30 by the elastic force in the axial direction generated by the strain given when the clamp ring 40 is fastened and fixed to the upper portion of the spindle motor 10. (See FIG. 7).

Another conventional magnetic disk device is disclosed in, for example, Japanese Patent Laid-Open No. 2-292786.

Referring to FIG. 1 of the publication, a conventional magnetic disk device is provided with a lower flange having an annular supporting surface, a hub for laminating a plurality of magnetic disk media, and a plurality of magnetic disk media thus laminated. A plurality of spacers, which are mounted between the spacers and each having an annular groove formed from the outside of the cylindrical surface toward the inside in the radial direction, and the second annular supporting surface at a position facing the annular supporting surface of the hub. And a clamp ring fastened and fixed to the upper part of the hub so as to compressively support the plurality of magnetic disk media and the plurality of spacers laminated on the hub in the axial direction (hereinafter referred to as second prior art). .

In the second conventional technique, the grooves provided in the plurality of spacers are elastically deformed,
The clamping force in the axial direction of the clamp ring applied to the plurality of magnetic disk media supported in layers can be almost evenly distributed, and the warp or distortion of the magnetic disk media can be reduced.

[0011]

However, these conventional magnetic disk devices have the following problems.

First, in the first prior art, the magnetic disk medium 20 is held in contact with the medium supporting surface of the flange portion by the elastic force in the axial direction generated from the clamp ring clamped and fixed to the upper portion of the spindle motor. But
Since the elastic force of the clamp ring also acts on the flange portion and distorts the flange portion itself, the magnetic disk medium is deformed along the medium supporting surface of the flange portion and warps or distorts the magnetic disk medium. However, there was a problem in that (see FIG. 8).

The warp or distortion of the magnetic disk medium tends to cause defective writing / reading of the magnetic head and head crash (a failure in which the magnetic head comes into contact with the magnetic disk medium and is destroyed). there were.

Next, the second conventional technique has a problem in that a high precision machining technique is indispensable because an annular groove is formed in the spacer ring itself.

Further, it may be difficult to form a groove depending on the material of the spacer ring, and only the spacer ring of a specific material can be used, or the number of working steps for forming the groove on the spacer ring is increased. There was a problem that it would increase.

Furthermore, when the precision of the grooves formed in each spacer ring is uneven and uneven, the tightening force from the clamp ring will be unevenly distributed to each magnetic disk medium, and each magnetic disk medium will be unevenly distributed. There is a problem that warpage or distortion occurs and the holding state becomes irregular as a whole.

The warp or distortion of the magnetic disk medium easily causes a write / read failure of the magnetic head and a head crash (a failure in which the magnetic head comes into contact with the magnetic disk medium and is destroyed). there were.

A main object of the present invention is to solve the above problems and to provide a magnetic disk device capable of stacking and fixing a plurality of magnetic disk media on a spindle motor without causing warping or distortion.

[0019]

A magnetic disk device according to the present invention is provided between a spindle motor having a flange portion for mounting a magnetic disk medium at a lower end thereof and the plurality of magnetic disk media laminated on the spindle motor. A plurality of spacer rings provided, a clamp ring that clamps and fixes the plurality of magnetic disk media and the plurality of spacer rings from the upper portion of the spindle motor, and is disposed between the flange portion and the magnetic disk media. And a shim having a shape capable of making line contact at a position facing the clamp ring.

[0020]

Embodiments of the present invention will now be described in detail with reference to the drawings.

Referring to FIG. 1, one embodiment of the present invention is
A spindle motor 1 rotating around a spindle shaft via a bearing, a plurality of magnetic disk media 2 stacked on the spindle motor 1, and a plurality of spacer rings 3 arranged between the plurality of magnetic disk media 2. A clamp ring 4 which is clamped and fixed from the upper portion of the spindle motor 1 so as to compressively support a plurality of magnetic disk media 2 and a plurality of spacer rings 3 stacked on the spindle motor 1 in the axial direction, and a medium support surface 6
And a flange portion 5 provided at the lower end portion of the spindle motor 1 and an annular shim 7 arranged between the medium supporting surface 6 of the flange portion 5 and the magnetic disk medium 2. .

The spindle motor 1 has a flat medium supporting surface 6 and is provided with an annular flange portion 5 for mounting the magnetic disk medium 2.

An annular shim 7 having a rectangular cross section is arranged between the flange portion 5 of the spindle motor 1 and the magnetic disk medium 2.

Since the shim 7 is formed of a member different from the flange portion 5, it is not necessary to bond the shim 7 to the flange portion 5, and the medium supporting surface 6 of the flange portion 5 and the magnetic disk medium 2 are not necessary.
It may be arranged at a predetermined position between and.

FIG. 2 shows the spindle motor 1 shown in FIG.
3 is an enlarged view of a lower end portion of FIG. 1, showing a state before a plurality of magnetic disk media 2 are clamped and fixed by a clamp ring 4.

FIG. 3 shows the spindle motor 1 shown in FIG.
4 is an enlarged view of the lower end of FIG. 1, showing a state in which a plurality of magnetic disk media 2 are clamped and fixed by a clamp ring 4.

FIG. 4 shows the spindle motor 1 shown in FIG.
FIG. 7 is an enlarged view of the lower end portion of FIG. 6, showing the case where a shim 7 having a large inner diameter is used.

FIG. 5 shows the spindle motor 1 shown in FIG.
FIG. 7 is an enlarged view of the lower end portion of FIG. 7, showing the case where a shim 7 having a small inner diameter is used.

Next, the operation of this embodiment will be described with reference to FIGS.

First, an annular shim 7 is arranged on the flange portion 5 of the spindle motor 1.

Subsequently, the magnetic disk medium 2 and the spacer ring 3 are alternately laminated (see FIG. 1).

Finally, the clamp ring 4 is tightened and fixed from above the spindle motor 1 with a screw or the like, and the plurality of magnetic disk media 2 are laminated and fixed to the spindle motor 1.

At this time, a downward force acts on the magnetic disk medium 2 by the tightening force of the clamp ring 4. Then, the flange portion 5 of the spindle motor 1 is bent by the tightening force of the clamp ring.

In this embodiment, since the shim 7 having an annular shape and a rectangular cross section is arranged between the flange portion 5 and the magnetic disk medium 2, the magnetic disk medium 2 and the shim 7 have an inner diameter of the shim 7. Therefore, even if the flange portion 5 is bent by the tightening force of the clamp ring 4, the bending does not affect the magnetic disk medium 2 unlike the case of surface contact (Fig. 2 and FIG. 3).

Therefore, a plurality of magnetic disk media 2 can always be horizontally supported in layers regardless of the bending of the flange portion 5.

Further, the warp or distortion of the magnetic disk medium 2 can be finely adjusted by shifting the point of action of the force of the clamp ring 4 and the flange portion 5 on the magnetic disk medium 2 to an appropriate position interval. .

That is, by increasing the inner diameter of the shim 7, the downward force of the clamp ring 4 is applied to the magnetic disk medium 2.
If the point at which the upward force of the shim 7 acts on the magnetic disk medium 2 is outside the point that acts on the magnetic disk medium 2, a bending moment acts on the magnetic disk medium 2 and the magnetic disk medium 2 warps up. (See FIG. 4).

On the contrary, the inner diameter of the shim 7 is reduced so that the shim 7
If the point where the downward force of the clamp ring 4 acts on the magnetic disk medium 2 is outside the point where the upward force of the magnetic disk medium 2 acts on the magnetic disk medium 2, a bending moment acts on the magnetic disk medium 2. As a result, the magnetic disk medium 2 comes to warp (see FIG. 5).

In this way, the magnetic disk medium 2 can always be kept in a horizontal state.

Although it is conceivable to form such a structure on the flange portion 5 of the spindle motor 1 in order to obtain such an effect by the line contact, the structure is formed directly on the flange portion 5. Compared with the case, the present embodiment has an effect of excellent manufacturability.

That is, it is easier to machine the annular shim 7 than to directly machine the flange portion 5 of the spindle motor 1, and the machining accuracy can be improved.

Further, since it may be difficult to process depending on the material of the spindle motor 1, this embodiment is also effective from this point.

Further, the present embodiment has an effect that the material of such shim 7 can be freely selected regardless of the material of the spindle motor 1.

For example, when the spindle motor 1, the magnetic disk medium 2, and the clamp ring 4 are made of different materials, distortion (heat off track) occurs due to the difference in the coefficient of thermal expansion.
It is conceivable that this will cause troubles in data recording / reproducing of the magnetic disk medium 2, but in the present embodiment, such thermal distortion can be prevented by appropriately selecting the material of the shim 7. is there.

Further, although the shim 7 having a rectangular sectional shape is used in this embodiment, the same effect can be obtained by manufacturing and processing the shim 7 having a triangular or circular sectional shape.

[0046]

As described above, in the magnetic disk device of the present invention, since the shim having a rectangular cross section is arranged between the flange portion provided at the lower end of the spindle motor and the magnetic disk medium. The magnetic disk medium and the shim come into line contact with each other at a position determined by the inner diameter of the shim, so that a plurality of magnetic disk media can always be stacked and supported horizontally regardless of the bending of the flange portion.

Further, in the magnetic disk device of the present invention, it is possible to appropriately finely adjust the warp or distortion of the magnetic disk medium by appropriately selecting and using shims having different inner diameters.

Furthermore, the magnetic disk device of the present invention can be easily machined and the machining accuracy can be improved by forming the shim with a member different from the spindle motor.

In addition, in the magnetic disk device of the present invention, the material of the shim is appropriately selected in consideration of the material of other members such as the spindle motor, so that the thermal strain caused by the difference in the coefficient of thermal expansion is prevented. can do.

[Brief description of drawings]

FIG. 1 is a structural diagram of an embodiment of the present invention.

FIG. 2 is a partially enlarged view of the vicinity of a flange portion 5 shown in FIG.

FIG. 3 is a partially enlarged view of the vicinity of a flange portion 5 shown in FIG.

FIG. 4 is a partially enlarged view of the vicinity of a flange portion 5 when a shim 7 having a large inner diameter is used.

FIG. 5 is a partially enlarged view of the vicinity of the flange portion 5 when a shim 7 having a small inner diameter is used.

FIG. 6 is a structural diagram showing a conventional magnetic disk device.

7 is a partially enlarged view of a flange portion of the conventional magnetic disk device shown in FIG.

8 is a partial enlarged view of a flange portion of the conventional magnetic disk device shown in FIG.

[Explanation of symbols]

 1 Spindle Motor 2 Magnetic Disk Medium 3 Spacer Ring 4 Clamp Ring 5 Flange 6 Medium Support Surface 7 Shim 10 Spindle Motor 20 Magnetic Disk Medium 30 Spacer Ring 40 Clamp Ring 50 Flange 60 Medium Support Surface

Claims (4)

[Claims] 1. A spindle motor having a lower end provided with a flange portion for mounting a magnetic disk medium, a plurality of spacer rings provided between the plurality of magnetic disk media laminated on the spindle motor, and a plurality of the plurality of spacer rings. A clamp ring that clamps and fixes the magnetic disk medium and the plurality of spacer rings from the upper portion of the spindle motor, and is disposed between the flange portion and the magnetic disk medium,
A magnetic disk medium comprising a shim having a shape capable of making line contact at a position facing the clamp ring. 2. The magnetic disk drive according to claim 1, wherein the shim has a rectangular cross section. 3. The magnetic disk drive according to claim 1, wherein the shim has a triangular sectional shape. 4. The magnetic disk drive according to claim 1, wherein the shim has a circular cross section.