JPS6360459B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a disk clamp device for centering a recording disk on a turntable.

In an information recording/reproducing device such as a video disk, if the disk has a large center runout during recording/reproducing, the recording/reproducing head may be unable to follow the information and good recording/reproducing may not be performed. In order to solve these problems, there is a need to develop a disk clamping device for centering the disk on the turntable.

As a conventional example of such a disk clamp device, the configuration shown in FIG. 1 has been considered. In FIG. 1, 1 is a rotating shaft to which a turntable 2 is fixed. 3 engages with the shaft 1;
It is a centering hub that is slidable in the axial direction of the shaft 1 and has a tapered outer circumference, and is applied with an upward elastic pressing force by a push-up spring 4. Reference numeral 5 denotes a magnet holding plate made of a magnetic material fixed to the shaft 1, which functions to attract the magnet 6 and also functions to prevent the centering hub 3 from coming off. Reference numeral 7 denotes a clamp for fixing the disk 8, inside which is fixed an annular magnet 6, which attracts the magnet holding plate 5 fixed to the shaft 1.

The operation of the conventional disk clamp device during clamping will be described with reference to FIG. 2. During clamping, the magnet 6 and the magnet holding plate 5 are attracted to each other, and the clamp 7 is fixed to the shaft 1. At this time, the disk 8 mounted on the tapered portion of the centering hub 3 is pressed downward by the clamp 7 and comes into contact with the turntable 2 and is fixed therein. Further, during the above operation process, the disk 8 is simultaneously centered by the tapered portion of the centering hub 3. The problems of the above conventional example will be described below.

As shown in Fig. 3, when the disc 8 is hung on the centering hub 3 in an inclined state before clamping, the disc 8 and the centering hub 3 are in a state of engagement at the contact surface, and the disc 8 is pushed down by the clamp 7. In order to bring the turntable into close contact with the turntable 2, an excessive pressing force is required, and in extreme cases, the turntable may be clamped in an inclined position.
Centering is not performed. Furthermore, there is a risk that excessive force will be applied to the center hole of the disk 8, causing the center hole to deform.

In addition, since the centering of the disk 8 is performed at the same time as the clamping process, if the vertical force applied to the disk 8, that is, the clamping force is strong,
Accordingly, the frictional force between the disk 8 and the turntable 2 or the frictional force between the disk 8 and the clamp 7 increases, and there is a possibility that centering may become unstable. In order to reliably center the disk in this way, it is necessary to accurately grasp the clamping force, the frictional force of the disk generated by the clamp, and the spring force of the push-up spring 4 that pushes up the centering hub 3. Difficult to design.

The present invention aims to improve these conventional drawbacks and provide a disk clamping device that performs good disk centering, and will be described below with reference to the drawings. FIG. 4 is a configuration diagram of an embodiment applied to the present invention. In FIG. 4, the same members as those in the conventional example are designated by the same numbers. The magnet holding plate 5 has a tapered portion 5a on its outer periphery, which is a releasing means for releasing the contact between the push-down member 9 and the centering hub 3, which will be described later. A push-down member 9 serving as push-down means for pushing down the centering hub 3 is provided on the clamp 7 via a leaf spring 10, and the push-down member 9 can move in the radial direction of the disk 8. Also, the push-down member 9
is provided with a tapered portion 9a that engages with the tapered portion 5a of the magnet holding plate 5. The disk clamping operation in this configuration will be explained based on FIGS. 4 to 6. FIG. 5 shows an intermediate state diagram of the disk clamping operation, and FIG. 6 shows a clamping state diagram. As shown in FIG. 4, in the initial state, the disk 8 is in contact with the outer periphery of the centering hub 3, which is pushed upward by the push-up spring 4, and is not in contact with the turntable 2, or is in a state in which it is in partial contact. . When the clamp 7 is pushed down in this state, the push-down member 9 provided on the clamp 7 comes into contact with the upper surface of the centering hub 3 and pushes the centering hub 3 down. If you push down the clamp 7 further, the fifth
As shown in the figure, the disk 8 is in a state in which it is in uniform contact with the turntable 2 and separated from the outer peripheral tapered portion of the centering hub 3. At this time, since the tapered part 9a of the push-down member 9 and the tapered part 5a of the magnet holding plate 5 come into contact, the push-down member 9 presses down the centering hub 3 while holding the leaf spring 10.
Since the disk can be moved in the radial direction, it moves toward the outer circumference of the centering hub 3. However, in the state shown in FIG. 5, the clamp 7 and the disk 8 are not in contact with each other. Furthermore, clamp 7
As the push-down member 9 moves further toward the outer circumference of the centering hub 3, it becomes separated from the centering hub 3, and the centering hub 3 is pushed upward by the pushing force of the push-up spring 4. At this time, the disk 8, which is in uniform contact with the turntable 2, contacts the outer circumferential tapered part of the centering hub 3 while being in uniform contact with the turntable 2, and centering is performed. While uniformly contacting the outer circumferential tapered portion and remaining parallel to the disk contact surface of the turntable 2, it is pushed upward and comes into contact with the clamp 7. When the clamp 7 is pushed down in this state, the disk 8 and centering hub 3 are pushed down by the clamp 7, and the disk 8 is uniformly contacted and fixed to the turntable 2. At this time, the magnet 6 fixed to the clamp 7 and the magnet holding plate 5 fixed to the shaft 1 are attracted to each other, so that the disk 8 is securely fixed as shown in FIG.

As described above, in the present invention, the disk is once brought into uniform contact with the turntable to correct the disk inclination, and then the disk is centered, and then the disk is clamped. Since the disc is not clamped in the state, not only can centering be performed reliably, but also the disc will not be damaged because no excessive force is applied when centering the disc. Furthermore, since clamping is performed after centering the disk, the centering of the disk does not become unstable due to clamping force, unlike in the conventional case.

[Brief explanation of the drawing]

Fig. 1 is a cross-sectional view showing the process of clamping a disk in a conventional disk clamp device, Fig. 2 is a cross-sectional view showing a disk clamping state in a conventional disk clamp device, and Fig. 3 is a cross-sectional view showing a disk clamping state in a conventional disk clamp device. FIGS. 4 to 6 are cross-sectional views showing the operating state of one embodiment of the disk clamp device applied to the present invention, respectively. 1...shaft, 2...turntable, 3...
...Centering hub, 4... Push-up spring, 5...
... Magnet holding plate, 5a... Magnet holding plate taper part, 6... Magnet, 7... Clamp,
8...Disc, 9...Pushing down member, 9a...
Push-down member taper portion, 10...plate spring.

Claims (1)

[Claims] 1. A turntable that is fixed to a rotating shaft and holds a recording disk, and a tapered outer periphery that engages with the rotating shaft and is slidable in the axial direction of the rotating shaft, and that engages with the center hole of the recording disk. a centering hub that centers the recording disk at its tapered portion; a pressing member that presses the centering hub in one direction so as to come into contact with the recording disk; and a pressing member that presses the recording disk against the turntable. a clamp to be fixed; a push-down means held by the clamp and capable of abutting against the centering hub to move the centering hub; and a centering hub fixed to a rotary shaft or turntable and capable of freely abutting the push-down means. and a release means for releasing the contact between the pressing means and the pressing means, and the pressing means contacts the centering hub to bring the centering hub into contact with the recording disk before the clamp presses the recording disk. and then the release means comes into contact with the pushing down means to release the contact between the centering hub and the pushing down means,
A recording disk clamp device characterized in that the centering hub is brought into contact with the recording disk, and then the clamp presses the recording disk and fixes it to the turntable.