JPH0343706B2 - - Google Patents

Description

TECHNICAL FIELD The present invention relates to a magnetic disk device, and more particularly to a magnetic disk device in which a spindle drives a magnetic disk having a center hub at the center of the magnetic disk.

Prior Art In a conventional device of this kind, a structure was adopted in which a center hub is clamped and rotationally driven by a spindle and a pressing member of the hub as a clamping means for rotationally driving a magnetic disk.

Then, on the spindle side, the outer diameter (diameter) is slightly smaller than the inner diameter (center hole diameter) of the center hub.
The structure was such that a small spindle shaft was rotated and used as the rotation axis for the magnetic disk.

However, there are always variations in the inner diameter of the center hub and the diameter of the spindle shaft, resulting in the following drawbacks.

(1) If the inner diameter of the center hub is relatively smaller than the diameter of the spindle shaft, the spindle cannot be fitted and the center hub cannot reach the mounting reference surface.

(2) If the inner diameter of the center hub is relatively larger than the diameter of the spindle shaft, the center will not align when rotating the magnetic disk.
Track misalignment occurred, causing problems in terms of compatibility.

Purpose The present invention was made in order to eliminate the above-mentioned conventional drawbacks, and to improve centering accuracy even if there is a relative variation between the inner diameter of the center hub and the diameter of the spindle shaft. is possible,
It is an object of the present invention to provide a magnetic disk device that can be manufactured at low cost.

In order to achieve the above object, the present invention provides a magnetic disk device in which a magnetic disk having a center hub at the center is driven by a spindle, in which the spindle is tightly fitted into a center hole of the center hub, A ring-shaped elastic member whose diameter can be expanded and contracted, and a pressing means for pressing the upper surface of the elastic member almost uniformly from above in the axial direction of the spindle are provided, A configuration is adopted in which the magnetic disk is centered by compressing the elastic member by pressing and elastically deforming the elastic member in a direction in which it comes into contact with the inner circumferential surface of the center hub.

Embodiments Hereinafter, the present invention will be described in detail based on embodiments shown in the drawings.

FIG. 1 illustrates an embodiment of the present invention.
In the figure, the symbol 1 is the center hub.
It is fixed at the center of a magnetic disk 2 housed in a cassette (not shown). This center hub 1 has a center hole 1a in the center.

On the other hand, the reference numeral 3 designates a spindle, which is fixed to a drive shaft 6 rotated by a motor (not shown), with a spindle shaft 3a as a solid shaft member protruding from the center of its upper surface. The diameter of the center hole 1a is considerably smaller than the diameter of the center hole 1a (ie, the inner diameter of the center hub 1). A ring-shaped elastic member 7 is fitted on the outside of the small diameter spindle shaft 3a.

On the other hand, a pressing member 4 is provided above the spindle shaft 3a.
is attached so as to be movable up and down via a support arm 5 made of a spring member. The pressing member 4 has a single cylindrical shape that is open downward, and its inner and outer diameters are slightly larger than the diameter of the spindle shaft 3a.
It is smaller than the diameter of the center hole 1a.

Since this embodiment is configured as described above,
When the magnetic disk cassette is installed and descends toward the installation reference surface, which is the upper surface of the spindle 3, via a cassette guide (not shown), the elastic member 7 is moved into the center hole 1a together with the spindle shaft 3a, as shown in FIG. to fit.

When the pressing member 4 descends in this state and begins to fit into the center hole 1a, the ring-shaped elastic member 7
is crushed and elastically deformed to fill the space in the center hole 1a formed between the spindle shaft 3a and the center hub 1. This deformation is performed uniformly toward the inner and outer circumferential surfaces of the elastic member 7, and the outer circumferential surface of the elastic member 7 uniformly contacts the outer circumferential surface of the center hole 1a (i.e., the inner circumferential surface of the center hub 1). , this causes center hub 1
is accurately centered on the center of the spindle shaft 3a, achieving highly accurate centering.

Effects As is clear from the above description, according to the present invention, in a magnetic disk device in which a spindle drives a magnetic disk having a center hub in the center, the spindle fitted into the center hole of the center hub A ring-shaped elastic member that is tightly fitted and whose diameter can be expanded and contracted, and a pressing means that presses the upper surface of the elastic member almost uniformly from above in the axial direction of the spindle are provided, and the pressing means presses the spindle. The structure is such that the magnetic disk is centered by compressing the elastic member by pressure from the axial direction and elastically deforming the pressing member in a direction in which it contacts the inner circumferential surface of the center hub. By performing centering using the diameter expansion caused by compression of the spindle, it is possible to reliably absorb variations in the relative dimensions between the center hole and the spindle shaft, and to perform highly accurate centering. Moreover, there is no need to press-fit a diameter-expanding member into the inside of the spindle, which greatly simplifies the structure of this type of mechanism, and the elastic member can also be formed into a simple ring shape, resulting in a simple structure and low cost. An excellent effect can be obtained in that it can be manufactured at low cost.

[Brief explanation of drawings]

FIG. 1 is a longitudinal sectional side view of a main part of a magnetic disk device in a clamped state, illustrating an embodiment of the present invention. 1...Center hub, 1a...Center hole, 2
... Magnetic disk, 3... Spindle, 3a... Spindle shaft, 4... Pressing member, 5... Support arm, 6... Drive shaft, 7... Elastic member.

Claims (1)

[Claims] 1. In a magnetic disk device in which a magnetic disk having a center hub in the center is driven by a spindle, the spindle is tightly fitted into a center hole of the center hub, and its diameter is expanded and reduced. A flexible ring-shaped elastic member and a pressing means for pressing the upper surface of the elastic member almost uniformly from above in the axial direction of the spindle are provided, and the elastic member is pressed by the pressing means from the axial direction of the spindle. A magnetic disk device characterized in that the magnetic disk is centered by compressing and elastically deforming the elastic member in a direction in which it contacts the inner circumferential surface of a center hub.