JPS61214272A - Rotation driving device for disc-shaped recording medium - Google Patents

Abstract

PURPOSE:To eliminate remaining of eccentricity by providing a compressed air discharging means and a vacuum sucking means on the recording medium placing surface of a turntable and switching one of both means to the other. CONSTITUTION:Plural perforations 9 used for compressed air discharge and vacuum suction are provided at equal intervals on the disc placing surface of a turntable 8. Perforations 9 are connected to an air path 15, and a tube 12 to a vacuum source and a tube 13 to a compressed air source are switched by a switching valve 11. A disc 11 is floated by the compressed air pressure from perforations 9 to eliminate the force of friction, and the disc 1 is aligned completely. The tube 13 is switched to the tube 12 by the valve 11 after alignment of the disc 1, and air is sucked through perforations 9 to make the pressure of the space of a seat 10 negative, and the disc 1 is fixed to the turntable 8. Thus, residual eccentricity is eliminated completely to fix the disc on the turntable easily.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a rotational drive device for a device for recording high-density signals on a disk-shaped recording medium, and particularly to a device for automatically attaching and detaching a disk-shaped recording medium to and from a turntable. It is effective for

2. Description of the Related Art A conventional rotary drive device is shown in FIG. 4, and its configuration will be explained with reference to the drawings. Disc-shaped recording medium (hereinafter referred to as disk)
1 is mounted on turntable 2. 3 is a bearing and 4
is the drive motor for the evening table 2. Further, a centering guide member 6 is fixed to the rotation center of the turntable 20, and a centering member 6 having a tapered portion on a part of its outer circumference is fitted onto the guide portion of the guide member 5. Further, there is a spring 7 at the bottom of the centering member 6, which pushes the centering member 6 upward. The force is adjusted to be smaller than the weight of the disc.

When the disc 1 is mounted on the turntable 2, the disc 1 is centered by the center hole of the disc 1 coming into contact with the tapered portion of the centering member. The effect is shown in FIG. disc 1
When the disk 1 is eccentrically mounted on the turntable, the centering member 6 pushes up the disk 1 with the force of Fo, resulting in a component force F1 of Fo and a component force F2 of Fl.
occurs, and the disk 1 is moved in the direction A and eccentricity is removed.

Problems to be Solved by the Invention However, as shown in FIG. 6, a frictional force R acts between the disk 1 and the turntable 2. Therefore, an amount corresponding to the frictional force remains as eccentricity. This leads to an increase in dynamic imbalance when the disk rotates at high speed, and the vibrations have a significant impact on the recording of high-density signals.

Means for solving the problems and technical means of the present invention for solving the above problems are as follows:
The disc and turntable are kept out of contact for a short period of time when the disc is centered, eliminating contact friction.

Function The present invention provides a small hole for discharging compressed air on the surface on which the disc of the turntable is mounted, and discharges compressed air from the small hole while the disc is centered.
That pressure allows the disc to come out of contact with the turntable. As a result, there is no friction between the disc and the turntable, and there is no residual eccentricity.

Example An embodiment of the present invention will be described below with reference to the accompanying drawings.

In FIGS. 1 and 2, the disc 1 is mounted on a turntable 8. As shown in FIGS. 3 is the bearing and 4 is the turntable 8
This is the drive motor for the. Further, a centering guide member 5 is fixed to the rotation center of the turntable 80,
A centering member 6 having a tapered part on its outer periphery is fitted onto the guide portion of the guide member 5. Also, the centering member 6 is sufficient. In addition, the disk mounting surface of the turntable 8 has a small hole e that serves both for compressed air discharge and vacuum suction.
A plurality of holes 9 are provided at equal intervals, and seats 1o are provided around the small holes to maintain pressure.
is guided to the switching pulp 11 by. The switching pulp 11 electrically switches between a tube 12 leading to a vacuum source and a tube 13 leading to a compressed air source.

Next, the operation will be explained using FIG. 3.

When the disc 1 is eccentrically mounted on the turntable 8, the disc 1 is pushed up by the force F by the centering member 6, resulting in a component force F of υF0 and F
A component force F2 is generated. This is the force that removes eccentricity. Conventionally, the friction force R between the disc 1 and the turntable 2 was applied at the same time as F2 was activated (Figure 6).
However, according to this embodiment, compressed air is discharged from the small hole 9, and the air pressure causes the disk 1 to float by a distance a, thereby eliminating the frictional force.

The disk 1 is therefore perfectly centered. After the disk 1 is aligned, the pulp 11 shown in FIG. Q to be fixed Here, the relationship between the compressed air pressure and the spring force F0 is set to a value such that the air flow in the gap between the turntable 8 and the disk 1 becomes a laminar flow. By the way, the gap a is 1
It is desirable to set the thickness to about 0 μm.

Furthermore, the means for floating the disk is not limited to the structure of the above-described embodiment, and the number of small holes and the size of the seat are not limited to the above, as long as the structure can make the flying height uniform.

Effects of the Invention As described above, according to the present invention, simply by mounting a disk on the turntable, it is possible to easily and completely eliminate residual eccentricity and fix the disk to the turntable. Therefore, the dynamic unbalance under high rotation conditions is extremely small, which makes it extremely effective, especially in a recording device that automatically attaches and detaches a disk to and from a turntable.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional perspective view showing the main parts of an embodiment of the rotary drive device of the present invention, FIG. 2 is a cross-sectional view of the rotary drive device of the present embodiment, and FIG. 3 is for explaining the operation of the present embodiment. A sectional view of the main parts of
FIG. 4 is a cross-sectional view of a conventional rotary drive device, and FIG. 5 is a cross-sectional view of essential parts for explaining the operation of the conventional example. 1...Disc-shaped recording medium (disc), 3...
...Bearing, 4...Motor, 5...
Centering guide member, 6...Centering member, 7...Spring, 8...Turntable, 9...Small hole, 1o... 11.
...Switching valve, 12,13.14...
...Tube, 15...Kudo. Name of agent: Patent attorney Toshio Nakao and 1 other person7-
--1fj2 8---Turn Chi 1 Le 10-11 No Takumi Figure 3 F. f-11 yen chopsticks age sleep practice key seven-goo

Claims (1)

[Claims] A turntable on which a disc-shaped recording medium having a center hole is mounted, a centering guide member protruding from the rotation center of the turntable, a centering member fitted onto the guide member and having a tapered portion on a part of the outer periphery; an elastic member that generates a force to lift the centering member upward, and a compressed air discharge means and a vacuum suction means are provided on the surface of the turntable on which the recording medium is mounted,
A rotational drive device for a disc-shaped recording medium, further comprising a switching means for switching between the compressed air discharge means and the vacuum suction means.