JPS63259863A - Disk clamping device - Google Patents

Abstract

PURPOSE:To stably clamp a disk by adhering an attraction hub of a disk and a magnet buried in a turntable together with their counter faces formed into wave shapes. CONSTITUTION:A ring-shaped magnet 12 buried in a turntable surface 10a of a turntable 10 and an adsorbing hub 9 of a disk substrate 8 have the counter wave-shaped faces 9a and 12a respectively in the circumferential direction of a disk 7. When the hub 9 is attracted by the magnet 12, the clamping force is fixed since no gap exists between the hub 9 and the magnet 12. Thus the disk 7 is stably clamped with no slip produced when the revolution of the disk 7 is started and stopped.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention This invention relates to a disk clamping device for optical disks and the like.

PRIOR ART Page 2 A conventional disc clamp device has a configuration shown in FIG. In FIG. 3, reference numeral 1 denotes a disk, and a ring-shaped attraction hub 3 that attracts a magnet is fixed to the center of a substrate 2 having a center hole coated with a recording material. The turntable 4 also has a center shaft 5 that engages with the center hole of the substrate 2, and a ring-shaped magnet 6 is embedded in the turntable surface 4a. In such a configuration, the suction hub 3 of the disk 1
is attracted to the magnet 6 of the turntable 4, and the disk 1 is centered by engaging with the center hole of the substrate 2 and the center shaft 5 of the turntable 4, and the substrate 2 and the turntable surface 4a are brought into close contact for positioning. is performed and the disc is clamped.

Problems to be Solved by the Invention However, in the disk clamp device having such a configuration, it is necessary to provide a gap between the suction hub and the magnet. However, since the adsorption force is inversely proportional to the square of the gap distance, the adsorption force will vary significantly depending on variations in the gap distance. As a result, if the adsorption force is weak, the clamping force will not be sufficient and the disc and turntable will slip when the disc rotation starts and stops on the 3rd page hour, causing scratches on the disc surface and generating dust. There have been problems in that it adheres to increase surface runout, or it adheres to optical systems such as objective lenses, degrading signal quality.

SUMMARY OF THE INVENTION An object of the present invention is to provide a disk clamping mechanism in which the clamping force is constant and the disk and turntable do not slip when the disk rotation starts or stops.

Means for Solving the Problems In order to solve the above-mentioned problems, the present invention has provided that the cross-sectional shape of the opposing surface between the attraction hub and the magnet is wavy along the circumferential direction of the disk, so that it does not overlap with the turntable surface. By creating a configuration in which the wavy portions of the adsorption hub and magnet can come into contact once the substrate surfaces are in close contact, a disk clamp can be obtained in which the clamping force is constant and the disk and turntable do not slip when the disk rotation starts or stops. .

Effect of the present invention With the above-described configuration, the wavy portions of the attraction hub and the magnet come into contact when the turntable surface and the substrate surface come into close contact, so the attraction force becomes constant, and furthermore, the wavy portion of the attraction hub and the magnet comes into contact with each other. Because they mesh, the disc and turntable do not slip when the disc starts or stops rotating, allowing stable disc clamping.

EXAMPLE Hereinafter, an example of the present invention will be described based on the accompanying drawings. In FIG. 1, reference numeral 7 denotes a disk, and a ring-shaped attraction hub 9 that attracts a magnet is fixed to the center of a substrate 8 having a center hole coated with a recording material. The turntable 10 also has a center shaft 11 that engages with the center hole of the substrate 8, and a ring-shaped magnet 12 is embedded in the turntable surface 10a. Further, the cross-sectional shapes 89a and 12a of the opposing surfaces of the suction hub 9 and the magnet 12 are wavy along the circumferential direction of the disk 7, and when the turntable surface 10a and the substrate surface come into close contact, the suction hub 9 and The structure is such that the wavy portion can come into contact with the magnet 12. In this configuration, the attraction hub 9 of the disk 7 is attracted to the magnet 12 of the turntable 10, and the disk 7 is centered by engaging with the center hole of the substrate 8 and the center shaft 11 of the turntable 10. To go. Thereafter, the wavy surface 9a of the adsorption hub 9 and the wavy surface 12 of the magnet 12a come into contact, and the wavy surfaces engage and attract each other, and the substrate 7 and turntable surface 10a come into close contact, completing positioning as shown in FIG. . As a result, since the wavy surface 9a of the suction hub 9 and the wavy surface 12 of the magnet 12a are in contact with each other, there is no gap between the suction hub and the magnet as in the conventional case, so variations in the suction force are reduced and stability is achieved. A constant clamping force can be generated. Further, since the wavy surface 9a of the suction hub 9 and the wavy surface 12 of the magnet 12a engage and attract each other, the disk and turntable do not slip when the disk rotation starts or stops, and stable disk clamping can be performed.

Effects of the Invention In the present invention, a disk, in which a ring-shaped attraction hub that attracts a magnet is fixed to the center of a substrate coated with a recording material, is attracted by a magnet to a tarpaulin table in which a ring-shaped magnet is embedded. This is a disk clamping mechanism that positions the turntable surface and the board surface by adhering the turntable surface and the substrate surface using the adsorption force of the hub. By configuring the structure so that the wavy portions of the suction hub and magnet come into contact when the turntable surface and the board surface come into close contact, the disc clamping force becomes constant, and furthermore, the suction hub and magnet Since the corrugated portions of the discs engage with each other, the disc and turntable do not slip when the disc rotation starts or stops, allowing stable disc clamping.

[Brief explanation of the drawing]

FIG. 1 is an exploded perspective view of a disc clamping device according to an embodiment of the present invention, FIG. 2 is a sectional front view of the disc clamping state of the same device, and FIG. 3 is a sectional front view of a conventional disc clamping device. 7... Disk, 8... Board, 9...
...Suction hub with wavy surface 10...
Turntable, 11... Center axis, 12.
...Magnet with wavy surface Figure 1 Figure 2 Figure 3

Claims (1)

[Claims] A ring-shaped suction hub that attracts a magnet is fixed to the center of a substrate coated with recording material, and the disk is attracted to a turntable in which a ring-shaped magnet is embedded by the attraction force between the magnet and the suction hub. This is a disk clamping device that positions the turntable surface and the substrate surface by bringing them into close contact with each other. A disk clamping device characterized in that the wavy portion of the adsorption hub and the magnet can come into contact when the substrate surface is brought into close contact with the disk clamping device.