JPH0644721A - Magnetic disk device - Google Patents

Abstract

PURPOSE:To eliminate contact between the inner ring of a magnetic disk and the outer ring of a spindle hub, to reduce occurrence of dust at the time of assembling and to reduce a thermal off track. CONSTITUTION:Three columns 4 rotating eccentrically are attached to the outer ring part of the spindle hub 3, and the outer periphery of these columns 4 are set so as to become minimum from a hub center, and the magnetic disk 1 is attached, the magnetic disk 1 is set to the center of the spindle hub 3 by rotating three columns 4 and cramped by a disk cramp. Thereafter, three columns 4 are rotated and made a non-contact state with the inner ring of the magnetic disk 1 and removed. Thus, since the inner ring of the magnetic disk 1 and the outer ring of the spindle hub 3 are assembled without being in contact with each other, no dust occurs and the thermal off track as well is reduced.

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, and more particularly to a structure of a spindle hap and a magnetic disk assembly in the magnetic disk device.

[0002]

2. Description of the Related Art In recent magnetic disk devices, the storage density has increased as the storage capacity has increased, and along with this, it has become necessary to improve the positioning accuracy of the magnetic head with respect to the magnetic disk.

The magnetic head positioning means in the magnetic disk device is provided with a dedicated magnetic head (servo head) for positioning operation, and positioning information is previously stored on the storage surface (servo surface) of the magnetic disk corresponding to this servo head. It is recorded in advance, and this positioning information is read by a servo head. Therefore, the relative positional deviation between the servo head and the other magnetic head, and the relative positional deviation between the servo surface and the storage surface of the other magnetic disk are originally related to the track to be followed. A deviation amount, that is, an off-track amount, and the smaller the off-track amount, the higher the positioning accuracy.

However, in an actual magnetic disk device, an off-track amount exceeding the allowable limit may occur due to various factors. Particularly, the off-track caused by the temperature rise of the magnetic disk device itself or the change of the environmental temperature is called a thermal off-track, which is one of the most important factors. This thermal off-track is caused by the difference in the coefficient of thermal expansion between the mechanical components that make up the magnetic disk device.

In order to improve the reliability of the magnetic disk device, the magnetic disk and the magnetic head are sealed with a base plate or the like, and a filter is provided in the magnetic disk device to keep the atmosphere of the magnetic disk and the magnetic head clean. It has a structure that prevents dust from entering between the magnetic head and the magnetic head and prevents a head crash.

In the conventional magnetic disk device, as shown in FIG. 5, a spindle hub 3b, in which a plurality of magnetic disks 1 are stacked with a predetermined gap, rotates. The shaft 2 fixed to the base plate 10a points to the spindle hub 3b via bearings 9 provided at both upper and lower ends thereof. A rotor 11 fixed to the spindle hub 3b and a stator 12 fixed to the shaft 2 are attached as a spindle driving motor.

[0007]

In this conventional magnetic disk device, in order to reduce the amount of unbalance of the magnetic disk 1, the inner ring of the magnetic disk 1 and the spindle hub 3b.
Has a small gap with the outer ring, and when the magnetic disk 1 is inserted into the spindle hub 3b during assembly, there is a risk that the outer ring of the spindle hub 3b will be connected to the inner ring of the magnetic disk 1 to generate dust due to abrasion. is there.

Further, the magnetic disk 1 is the spindle hub 3
The outer ring of the spindle hub 3b is in contact with the inner ring of the magnetic disk 1 in the state of being attached to the disk b, and the spindle hub 3b pushes the magnetic disk 1 at the contact point due to the difference in linear expansion coefficient due to the difference in members, so-called thermal off. It has the drawback of causing a truck.

[0009]

According to a first aspect of the present invention, there is provided a shaft fixed to a base plate which is located at the center of a plurality of magnetic disks and encloses the plurality of magnetic disks, and the plurality of the shafts are provided with bearings at both ends thereof. Holding a magnetic disk of the spindle hub for rotating at a predetermined interval, and a drive motor attached to the inside of the spindle hub for giving a rotational motion to the spindle hub. The surface of the spindle hub is provided with three concave portions or convex portions, and the end surface is eccentrically provided with three cylindrical portions having convex portions or concave portions. The three cylinders are attached so as to correspond to each other, and the three cylinders are rotated to rotate the plurality of magnetic disks. After the center of the center of the spindle hub is positioned to match, characterized by securing the plurality of magnetic disks.

According to a second aspect of the present invention, a shaft which is located at the center of a plurality of magnetic disks and which is fixed to a base plate which encloses the plurality of magnetic disks, and a plurality of the magnetic disks which are provided with bearings at both ends of the shaft are provided in predetermined positions. In a magnetic disk device comprising a spindle hub which holds and rotates at intervals and a drive motor which is attached to the inside of the spindle hub and gives rotational motion to the spindle hub, the spindle hub is rotatable between upper and lower two plates. One elliptic cylinder is provided, and the three elliptic cylinders are rotated and positioned so that the centers of the plurality of magnetic disks and the spindle hub coincide with each other, and then the plurality of magnetic disks are fixed. And

According to a third aspect of the present invention, a spindle hub for holding and laminating a plurality of magnetic disks at predetermined intervals, a shaft located at the center of the plurality of magnetic disks and fixedly rotating the spindle hub, and this shaft. And a base plate fixed to bearings for rotatably holding the shaft, the surface of the spindle hub holding the magnetic disk is provided with three recesses or protrusions, and the end surface is biased. And three cylinders having a convex portion or a concave portion at the center thereof, and the three circular cylinders are attached so that the convex portions or the concave portions of these circular columns correspond to the concave portions or the convex portions of the spindle hub, respectively, Position the cylinder by rotating the cylinder so that the centers of the magnetic disks and the spindle hub match. After, characterized by securing the plurality of magnetic disks.

A fourth invention is a spindle hub for holding and laminating a plurality of magnetic disks at predetermined intervals, a shaft located at the center of the plurality of magnetic disks and fixedly rotating the spindle hub, and this shaft. And a base plate fixed to bearings for rotatably holding the shaft, the spindle hub having three rotatable elliptic cylinders between two upper and lower plates, The elliptic cylinder is rotated to position the magnetic disks so that the centers of the magnetic disks and the spindle hub are aligned with each other, and then the magnetic disks are fixed.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, the present invention will be described with reference to the drawings.

FIG. 1 (a) is a sectional view showing a first embodiment of the present invention, and FIG. 1 (b) is a view taken in the direction of arrow A in FIG. 1 (a). In FIG. 1, a plurality of magnetic disks 1 are held at predetermined intervals, stacked on a spindle hub 3, and fixed to the spindle hub 3 by a disk clamp 13. The shaft 2 is located at the center of the magnetic disk 1 and is fixed to the base plate 10 that contains the magnetic disk 1 and the magnetic head 7, and rotatably holds the spindle hub 3 via bearings 9 at the upper and lower ends thereof.

A rotor 11 and a stator 12 of a drive motor that gives a rotary motion to the magnetic disk 1 are mounted inside the spindle hub 3 and the shaft 2. A magnetic head 7 that records and reproduces information on and from the magnetic disk 1 is positioned at a predetermined position on the magnetic disk 1 by a carriage 8.

Next, the magnetic disk 1 of the spindle hub 3
Three recesses are provided on the receiving surface to reduce the outer diameter of the spindle hub 3. On the other hand, eccentricity is provided at the end to provide a convex portion 3
Attach the four cylinders 4, 5 and 6 to the recesses of the spindle hub 3 respectively, and rotate the cylinders 4, 5 and 6 to rotate the cylinders 4, 5 and 6
The outer ring of is set to the minimum distance from the center of the spindle hub 3. At this time, the inner ring of the magnetic disk 1 and the columns 4, 5, 6
The gap between the spindle hub 3 and the outer ring of the spindle hub 3 is increased so that the magnetic disk 1 and the cylinders 4, 5, 6 and the spindle hub 3
Avoid contact with.

Next, after inserting the entire magnetic disk 1 into the spindle hub 3, the three cylinders 4, 5 and 6 are rotated to align the center of the magnetic disk 1 with the center of the spindle hub 3.
Minimize the amount of unbalance. And again the cylinder 4,
Rotate 5 and 6 to remove the cylinder and clamp the disc 13
Then, the magnetic disk 1 is attached to the spindle hub 3.
By assembling as described above, the outer ring of the spindle hub 3 and the inner ring of the magnetic disk 1 do not come into contact with each other, and the amount of imbalance of the magnetic disk 1 can be minimized.

FIG. 2 (a) is a sectional view showing the second embodiment, and FIG. 1 (b) is a sectional view taken along line XX in FIG. 2 (a). The difference between the first embodiment shown in FIG. 1 and the second embodiment shown in FIG. 2 is that three elliptic cylinders 16, 17, and 18 are used as part of the spider hub. In the structure of this spindle hub, elliptical columns 16, 17, 18 are mounted between the plate L15 and the plate U14 with the shaft 2 as the center, and the elliptic columns 16, 17, 18 are mounted so as to be rotatable. Even with such a spindle hub, the inner ring of the magnetic disk 1 and the outer ring of the spindle hub do not come into contact with each other as described above, and the unbalance amount of the magnetic disk 1 can be minimized for assembly.

FIGS. 3 and 4 show third and fourth embodiments using a shaft rotating type spindle, and the inner ring of the magnetic disk is the same as those described in the embodiments of FIGS. 1 and 2, respectively. And the outer ring of the spindle hub do not come into contact with each other, so that the unbalance amount of the magnetic disk can be reduced.

[0020]

As described above, according to the magnetic disk device of the present invention, by setting a cylinder or an elliptic cylinder that can be eccentrically rotated on the outer ring portion of the spindle hub, the magnetic disk device can be used as an inner ring of the magnetic disk during assembly. The gap between the outer circumference of the cylinder or the elliptic cylinder and the outer ring of the spindle hub can be increased, and the amount of unbalance of the magnetic disk can be minimized. Therefore, there is no contact between the inner ring of the magnetic disk and the outer ring of the spindle hub, and the generation of dust due to wear is eliminated.

Furthermore, since there is no contact between the inner ring of the magnetic disk and the outer ring of the spindle hub even after assembly, there is an effect that thermal off-track does not occur.

[Brief description of drawings]

FIG. 1A is a sectional view showing a first embodiment of the present invention, and FIG. 1B is a view taken in the direction of an arrow A in FIG. 1A.

FIG. 2A is a sectional view showing a second embodiment of the present invention, and FIG. 2B is a sectional view taken along line XX of FIG. 2A.

FIG. 3A is a sectional view showing a third embodiment of the present invention, and FIG. 3B is a view taken in the direction of arrow B in FIG. 3A.

FIG. 4A is a sectional view showing a fourth embodiment of the present invention, and FIG. 4B is a sectional view taken along line YY of FIG. 4A.

FIG. 5 is a cross-sectional view showing a conventional magnetic disk device.

[Explanation of symbols]

 1 Magnetic Disk 2 Shaft 3 Spindle Hub 4-6 Cylinder 7 Magnetic Head 8 Carriage 9 Bearing 10 Base Plate 11 Rotor 12 Stator 13 Disk Clamp 14 Plate U 15 Plate L 16-18 Elliptic Cylinder

Claims (4)

[Claims] 1. A shaft which is located at the center of a plurality of magnetic disks and which is fixed to a base plate which encloses the plurality of magnetic disks, and which holds the plurality of magnetic disks at predetermined intervals via bearings at both ends of the shaft. In a magnetic disk device comprising a rotating spindle hub and a drive motor attached to the inside of the spindle hub and giving a rotational motion to the spindle hub, three recesses or protrusions are provided on the surface of the spindle hub holding the magnetic disk. And three cylinders that are provided eccentrically on the end surface and have convex portions or concave portions, and the convex portions or concave portions of these circular columns respectively correspond to the concave portions or convex portions of the spindle hub. And rotate the three cylinders to rotate the centers of the plurality of magnetic disks and the spindle hub. A magnetic disk device characterized in that the plurality of magnetic disks are fixed after positioning so that the centers thereof coincide with each other. 2. A shaft which is located at the center of a plurality of magnetic disks and which is fixed to a base plate which encloses the plurality of magnetic disks, and which holds the plurality of magnetic disks at predetermined intervals via bearings at both ends of the shaft. In a magnetic disk device comprising a rotating spindle hub and a drive motor attached to the inside of the spindle hub and giving a rotational motion to the spindle hub, the spindle hub includes three rotatable elliptic cylinders between two upper and lower plates. A magnetic disk, comprising: rotating the three elliptic cylinders to position the plurality of magnetic disks so that the centers of the plurality of magnetic disks and the spindle hub are aligned with each other, and then fixing the plurality of magnetic disks. apparatus. 3. A spindle hub for holding and stacking a plurality of magnetic disks at predetermined intervals, a shaft located at the center of the plurality of magnetic disks for fixing and rotating the spindle hub, and attached to both ends of this shoft. In a magnetic disk device including a base plate for fixing a bearing for rotatably holding the shaft, three concave portions or convex portions are provided on a surface of the spindle hub for holding the magnetic disk, and an end surface is eccentrically convex. 3 cylinders having a portion or a recess, and the 3 cylinders are attached so that the projections or recesses of these cylinders correspond to the recesses or projections of the spindle hub, respectively, and the 3 cylinders are rotated. After positioning so that the centers of the plurality of magnetic disks and the center of the spindle hub are aligned with each other, A magnetic disk device characterized by fixing a number of magnetic disks. 4. A spindle hub for holding and stacking a plurality of magnetic disks at predetermined intervals, a shaft positioned at the center of the plurality of magnetic disks for fixing and rotating the spindle hub, and attached to both ends of the shaft. In a magnetic disk device including a base plate to which a bearing for rotatably holding the shaft is fixed, the spindle hub has three rotatable elliptic cylinders between two upper and lower plates, and the three elliptic cylinders are rotated. The magnetic disk device is characterized in that the plurality of magnetic disks are positioned so that the centers of the plurality of magnetic disks and the center of the spindle hub coincide with each other, and then the plurality of magnetic disks are fixed.