JPH0411255Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention has a magnetic plate movably mounted in the turntable body in both the radial direction and the rotational direction, and a magnet built in the magnetic plate and the clamper. The present invention relates to an improvement in a disk-shaped recording medium holding device that holds a disk-shaped recording medium using suction force.

[Prior art] A turntable driven by a motor and a clamper that presses a disk-shaped recording medium against the recording medium mounting surface of the turntable and rotates together with the turntable, and the clamper has a built-in permanent magnet. In addition, a disk-shaped recording medium holding device in which the turntable is constructed by incorporating a magnetic plate attracted by the magnet in a turntable main body made of synthetic resin is, for example, disclosed in Japanese Utility Model Application Publication No. 1986-
33192, etc., in conventional devices of this type, a magnetic plate is fixed inside the turntable body by means of adhesive or press-fitting, and the clamper is attached to the turntable using magnetic attraction force. attracted to,
The recording medium is held between the two.

[Problems to be solved by the invention] In the conventional configuration as described above, the magnetic plate is firmly fixed inside the turntable body made of synthetic resin using means such as adhesion or press-fitting. Due to the difference in coefficient of thermal expansion between the magnetic plate and the magnetic plate, there was a risk that distortion would occur in both. In particular, deformation of the turntable main body causes a decrease in the recording medium clamping force between the clamper and the turntable, so a solution to this problem has been desired.

Therefore, the purpose of the present invention is to reduce the recording medium clamping force between the clamper and the turntable in a disk recording medium holding device in which the clamper has a built-in magnet and the turntable has a built-in magnetic plate that is attracted to the magnet. The goal is to make it possible to prevent it.

[Means for Solving the Problems] In order to achieve the above object, the present invention includes a turntable body made of synthetic resin in which a magnetic plate is movable over a certain range in both the radial direction and the rotational direction. and was mounted so that it could move in the axial direction within a range that did not protrude from the recording medium mounting surface.

[Function] Even if a temperature change occurs, the turntable body and the magnetic plate are not fixed to each other, so no distortion occurs due to the difference in thermal expansion between the two. Therefore, it is possible to prevent a decrease in the recording medium clamping force between the turntable and the clamper.

[Embodiment] The figure shows an embodiment of the present invention, and FIG. 1 is a sectional view of a disk-shaped recording medium holding device. A motor 2 is fixed to the lower surface of the chassis 1, and a rotating shaft 3 of the motor 2 projects to the upper surface of the chassis 1. A pulley 4 is attached to the rotating shaft 3,
A belt 6 is stretched between this pulley 4 and another pulley 5 attached to the chassis 1, and the tension of the belt 6 prevents the rotating shaft 3 from running out in the radial direction. Note that the rotational force may be transmitted to other necessary locations via the pulley 5 or belt 6. A pulley 4 is attached to the rotating shaft 3.
A turntable 7 is fixed at an upper position, and a disk-shaped recording medium D is placed on this turntable 7. The turntable 7 has a structure in which a magnetic plate 9, a centering member 10, and a compression coil spring 11 are housed in a turntable main body 8 made of synthetic resin, and the centering member 10 is constantly pushed upward by the spring. The tapered head is made to protrude upward from the upper surface of the turntable main body 8, that is, from the recording medium mounting surface 8a.

A clamper 12 is arranged above the turntable 7. The clamper 12 is suspended from a clamper support 13 and moves up and down by the rotation of the support 13.The clamper body 12 is made of synthetic resin.
An annular permanent magnet 15 is housed in the clamper body 4, and the upper opening of the clamper body 14 is closed with a cover plate 16. The clamper main body 14 is formed into a bottomed annular shape, and a fitting hole 17 is provided in the center into which the upper end of the rotating shaft 3 is fitted when descending.

The structure of the turntable 7 will be explained based on FIG. 2.

The turntable main body 8 has a cylindrical shape with a bottom, and four supporting pieces 18 are erected on the inner bottom surface at equal intervals in the circumferential direction, and these supporting pieces 18 and the peripheral wall of the turntable main body 8 An annular space 1 between
9 is formed. An engaging pawl 20 is provided protruding from the outer surface of each support piece 18 . Further, the upper part of the peripheral wall of the turntable main body 8 has a large diameter with the stepped portion 21 as a boundary, and the diameter of the upper portion of the peripheral wall of the turntable main body 8 is increased from the recording medium mounting surface 8a to the stepped portion 21.
The depth t ₁ is set slightly larger than the thickness t ₀ of the magnetic plate 9.

The magnetic plate 9 consists of an annular flat plate portion 9a and a short cylindrical portion 9b continuous to the inner circumference of the flat plate portion 9a,
All have a uniform plate thickness t ₀ . Further, the inner diameter d ₀ of the short cylindrical portion 9b is the same as that of the turntable 7.
The support plates 18 are set to be slightly larger than the outer diameter d ₁ of the cylinder. And the flat plate part 9a
Recesses 22 of the same shape are formed at equal intervals in the circumferential direction at four locations on the corners where the and short cylindrical portions 9b are in contact. Note that the circumferential width b ₀ of each depression 22 is set slightly larger than the circumferential width b ₁ of the engaging claws 20 provided on the four support plates 18 of the turntable 7. In this way, the short cylindrical portion 9 fits on the outside of the four support pieces 18..., and the four depressions 22... engage with the engaging claws 20..., but the depressions 22... The bottom surface of... is the engagement claw 20...
The dimensions of each part are such that the upper end surface of the flat plate part 9a does not protrude above the recording medium mounting surface 8a of the turntable main body 8 when in contact with the lower end surface of the turntable body 8.

When the above-mentioned magnetic plate 9 is assembled into the turntable body 8, the four support pieces 18 of the turntable body 8 are bent inwardly, and the support pieces 18 are moved over the engaging claws 20. ..., and simultaneously insert the four recesses 22... into the engaging claw 2.
0... is engaged. The magnetic plate 9 incorporated into the turntable main body 8 in this way has t ₀ <
Due to the dimensional relationships of t ₁ , d ₀ > d ₁ , and b ₀ >b ₁ , it is possible to move within a certain range in the radial direction and rotational direction. It is also movable in the axial direction within a range that does not protrude from the recording medium mounting surface 8a.

Therefore, the turntable body 8 due to temperature changes.
The difference in coefficient of thermal expansion between the turntable body 8 and the magnetic plate 9 is absorbed by the relative movement of the two, and there is no risk of distortion occurring in either the turntable body 8 or the magnetic plate 9.

Also, to roughly explain the operation of the above-mentioned disk-type recording medium holding device, when loading the recording medium D, first, with the clamper 12 positioned at the imaginary line position in FIG. Place it on the medium mounting surface 8a. At this time, since the centering member 10 is pushed upward by the compression coil spring 11, the center hole of the recording medium D fits into the tapered head of the centering member 10, and the recording medium D
horizontal positioning is performed. Then, when the clamper 12 is lowered, when the clamper 12 approaches the turntable 7 to some extent, the magnetic plate 9 is attracted to the permanent magnet 15 inside the turntable 7, and the clamper 12 is drawn toward the turntable 7 side. Then, the fitting hole 17 of the clamper 12 fits into the upper end of the rotating shaft 3, and the recording medium D is held between the turntable 7 and the clamper 12, as shown by the solid line in FIG. . In this state, the magnetic plate 9 is lifted off the stepped portion 21 by the magnetic attraction force of the permanent magnet 15, but the engaging claw 20
Since the amount of floating is regulated by . . . , the magnetic plate 9 will not protrude beyond the recording medium mounting surface 8a, and therefore the magnetic plate 9 will not come into contact with the recording medium D.

[Effects of the invention] According to the invention, by incorporating the magnetic plate into the turntable body so that it can move within a certain range in the radial direction, rotational direction, and axial direction, the turntable body and magnetic plate can be easily moved due to temperature changes. There is no risk of deformation, and a strong recording medium clamping force can always be obtained between the clamper and the turntable.

[Brief explanation of the drawing]

The figures show one embodiment of the present invention, in which Fig. 1 is a cross-sectional view of a disk-shaped recording medium holding device, Fig. 2 is an exploded perspective view of a turntable, and Fig. 3 is a cross-sectional view of a part of the turntable. FIG. 2...Motor, 7...Turntable, 8...
Turntable body, 8a... Recording medium mounting surface,
9... Magnetic plate, 12... Clamper, 15... Permanent magnet, 19... Annular space, 20... Engaging claw,
22... hollow.

Claims (1)

[Claims for Utility Model Registration] The invention consists of a turntable driven by a motor and a clamper that presses a disk-shaped recording medium against the recording medium mounting surface of the turntable and rotates together with the turntable, and a magnet is attached to the clamper. In a disk-shaped recording medium holding device, the turntable has a built-in magnetic plate that is attracted to the magnet in a turntable body made of synthetic resin. A circular space opening on the surface side is provided, and the magnetic plate is movable within a certain range in both the radial direction and the rotational direction with respect to the turntable body within this circular space, and the recording medium is disposed in the axial direction. A disk-shaped recording medium holding device characterized in that it is mounted movably within a range that does not protrude from a medium mounting surface.