JP2003187510A - Disk clamping mechanism - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a disk clamping mechanism which strongly holds a disk on a turntable by a nearly similar and stable holding force even if fluctuation occurs in a thickness dimension of the disk, has a pressing force to prevent the floating of the disk itself even during high-speed rotation, has a small magnetic noise, and deals with a thin motor. <P>SOLUTION: A turntable 4 is secured to the end of a rotary shaft 3 of a spindle motor 2 fixed to a motor fixing angle 1 of a recording/reproducing device. A clamper is supported in a suspended state by a support angle 6 of the recording/reproducing device so as to be coaxial to the axis of the rotary shaft 3 by a gap A with the end of the rotary shaft 3 of the spindle motor 2. The support angle 6 is made of a magnetic metal material such as an iron plate, its hole part 6a for inserting the clamper is constituted of a burring, and a ring-shaped magnet 7 having a thickness dimension smaller than the burring height dimension B is secured to its outer periphery 6b by pressure insertion, adhesion, or the like. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a disc clamp mechanism used in a disc recording medium, particularly an optical disc recording / reproducing apparatus.

[0002]

2. Description of the Related Art Conventionally, a recording / reproducing apparatus using an optical disk has a turntable fixed to a shaft of a spindle motor provided in the apparatus, and the optical disk is placed on the turntable and rotated to rotate the disk. Information is written or read.

However, if the optical disc mounted on the turntable has a slight in-plane center of gravity deviation or warpage,
In recent years, optical discs are used for high-speed rotation, so the centrifugal force causes the optical disc to slightly move on the turntable, causing the center of rotation to deviate, or causing the optical disc itself to rise, which causes the track of the rotating optical disc. There was a problem that the optical pickup deviated from it and it became impossible to read or record information.

Conventionally, in order to cope with the deviation of the rotation center of the optical disk itself, a method has been adopted in which the optical disk is firmly held on the mounting surface of the turntable during rotation. As this method, a ring-shaped hole is provided in the center of the turntable, and a ring-shaped magnet is provided in the hole, and with this magnet, an iron plate or the like suspended in a supporting angle of this recording / reproducing apparatus is provided. The optical disk is firmly held in the direction of the disk mounting surface of the turntable by magnetically attracting the clamper made of the thin magnetic metal plate to sandwich the mounted optical disk.

For lifting of the other optical disk itself, an attracting magnet is attached to the rotor side or stator side of the spindle motor, and a magnetic material is attached magnetically to the stator side or rotor side facing the gap. A method has been adopted in which the rotor portion, which fixes the turntable on which the optical disk is mounted, does not float up from the stator portion during rotation by attracting each other.

[0006]

However, the above-mentioned conventional method for preventing the rotation center deviation of the optical disc is such that, when a thick optical disc is placed, the magnetic attraction force between the ring-shaped magnet and the clamper for sandwiching the thick disc. May significantly decrease, and the problem of misalignment of the rotation center of the optical disk still occurs.

Conventionally, an optical disk has a stamper made based on a master plate mounted on a molding machine, and a transparent disk body is made by a resin molding process using an acrylic resin or the like. After that, the disc body is subjected to an aluminum reflection film vapor deposition process and a protective film coating process, and finally a title is displayed by attaching a label or printing to complete an optical disc. However, since it is mass-produced through such a manufacturing process, it is inevitable that the finished dimensions vary. According to the JIS standard, the thickness dimension that is particularly important for an optical disc is, for example, for an optical disc for a CD-ROM, the thickness standard is 1.20 mm, and the tolerance is +0.3 mm / -0.1 m.
The standard thickness of the optical disc for DVD is 1.20m
The m tolerance is defined as +0.3 mm / -0.06 mm.

The thickness dimension of the optical disc produced by the above-mentioned manufacturing process is a ring shape for sandwiching the disc with the upper limit thickness and the lower limit value even if it is controlled within the JIS standard. The holding force due to the magnetic attraction of the magnet and clamper may change significantly. This follows the damping characteristic that the force acting on the magnetic pole in Coulomb's law is inversely proportional to the square of the distance, and when the magnetic attraction mechanism is set in a place where this characteristic changes drastically, the center of rotation of the optical disc shifts. The above-mentioned problem is said to occur remarkably.

On the other hand, the above-mentioned method of preventing the floating of the optical disk has a problem that the number of parts of the attraction magnet and the magnetic material is increased and the assembly work is increased accordingly. Further, in such a component structure, the structure of the spindle motor itself becomes large, and there is a problem that it is not possible to cope with the trend of thinner markets. Furthermore, the addition of the attraction magnet in addition to the ring-shaped magnet increases the leakage magnetic flux, which causes a problem of increasing magnetic noise.

Therefore, the present invention solves the above problems by providing a pressing force that prevents the center of rotation from deviating even if the thickness of the optical disc fluctuates, and prevents the optical disc from rising even at high speed rotation. However, it is intended to provide a disk clamp mechanism which has a small magnetic noise and is compatible with a thin motor.

[0011]

In order to solve the above-mentioned problems, as in the invention described in claim 1, a turntable fixed to a rotary shaft of a spindle motor and a supporting angle support it in a suspended manner. Equipped clamper,
In the disc clamp mechanism for sandwiching a disc between the turntable and the clamper, the clamper includes a clamper body facing the turntable, a spring pressing member including a magnetic metal portion, and a spring member for expanding the spring holding member. The angle can be achieved by including a magnetic metal part and providing magnetic attraction means at the position of the supporting angle facing the spring pressing member.

Further, according to the invention described in claim 2, in the disc clamp mechanism, the rotation shaft can be achieved by being provided in a rotor portion facing the stator portion of the spindle motor with an axial gap. .

The magnetic attraction means may be a ring-shaped magnet fixed to the support angle, as in the invention described in claim 3, or the invention described in claim 4. As a ring-shaped magnet fixed to the spring pressing member, and the spring member is formed of a coil spring or a leaf spring as in the invention of claim 5, and the turntable is The disk clamp device can be obtained by setting the spring constant so that the magnetic attraction means is in the non-contact attraction state when the disk is placed and held.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a cross-sectional explanatory view of relevant parts showing a state immediately before a disc is clamped by a disc clamp mechanism according to an embodiment of the present invention. FIG. 2 is a cross-sectional view showing a further enlarged main part described in FIG. In FIGS. 1 and 2, a turntable 4 is fixed to an end of a rotary shaft 3 of a spindle motor 2 fixed to a motor fixing angle 1 of a recording / reproducing apparatus. The motor fixed angle 1 is attached to the recording / reproducing apparatus by a mechanism (not shown) so as to be movable in the axial direction of the rotary shaft 3. Further, the clamper is fixed to the recording / reproducing device so as to be coaxial with the axis of the rotary shaft 3 with a gap A from the end of the rotary shaft 3 included in the rotor part facing the stator part of the spindle motor 2. It is supported by the support angle 6 in a suspended manner.

The support angle 6 is fixed to the recording / reproducing apparatus and is made of a magnetic metal material such as an iron plate. The hole 6a through which the clamper is inserted is formed by burring and the outer circumference 6b has a thickness smaller than the burring height dimension B. A ring-shaped magnet 7 having a predetermined size and magnetized in the axial direction of the rotating shaft 3 is fixed by press fitting or adhesion. The support angle 6 may be a non-magnetic material, and the magnet 7 may be attached via a magnetic material or the like. This makes it possible to appropriately select the material properties required for each. In FIG. 2, 4a of the turntable 4 is a hemispherical projection for centering when the disc 11 is placed, and 4b is a non-slip member of the placed optical disc 11.

The clamper comprises a clamper body 5, a spring pressing member 8, a coil spring 9 and a stopper 10. The clamper body 5 is made of a disc-shaped elastic molding resin or the like. The spring pressing member 8 is made of a magnetic metal material such as an iron plate, and is inserted into and attached to the outer peripheral portion 5a of the end of the clamper body 5, and its outer diameter portion is formed to be larger than the outer diameter 6b of the burring of the support angle 6. ing. This spring pressing member 8 and the stopper 1 fixed to the end of the clamper 5 so as not to come off.
0, and between the spring pressing member 8 thus configured and the convex surface 5c of the clamper body 5 opposite to the optical disk pressing surface 5b, the inner diameter is larger than the outer peripheral diameter portion 5a of the clamper body 5 and the outer diameter is the support angle. A compression type coil spring 9 having a size smaller than the diameter of the hole 6a of 6 is provided.

In this state where the disc is not clamped, the burring end surface 6c of the support angle 6 is always in contact with the spring pressing member 8, and the pressing surface 5b of the clamper 5 is elastic in the axial direction. . The magnet 7 is set to have a thickness smaller than the burring height B of the support angle 6, and the spring holding member 8 and the support angle 6 are set.
Set the gap with the burring end 6c of
Adjust the strength of the magnetic attraction. In such a method requiring adjustment of the magnetic attraction force, as another method, the burring height dimension B of the support angle 6 is set to be equal to or less than the thickness dimension of the magnet 7, and the upper surface of the magnet 7 attracting the spring pressing member 8 is set. A thin non-magnetic material plate may be attached to and the thickness dimension thereof may be adjusted.

FIG. 3 is a cross-sectional explanatory view of the essential parts showing a state in which the disc is clamped by the disc clamp mechanism according to the embodiment of the present invention. FIG. 4 is a cross-sectional explanatory view of a main part showing the main part described in FIG. 3 in a further enlarged manner. From the state shown in FIG. 1, when the turntable 4 approaches the clamper body 5 side, the turntable 4 mounts the optical disk 11,
Eventually, the pressing surface 5b of the clamper body 5 starts to contact the disk 11, and then the coil spring 9 starts to compress,
The clamper main body 5 starts pressing so as to sandwich the disk 11 with the turntable 4.

Further, the turntable 4 is brought to a predetermined position.
When is moved, the clamper main body 5 strongly compresses the coil spring 9 as shown in FIGS.
The disk 11 placed on the optical disk 11 is strongly pressed, and the turntable 4 and the clamper main body 5 sandwich and hold the optical disk 11. At this time, the magnetic force of the magnet 7 and the spring constant of the coil spring 9 are set so that the burring end surface 6c of the support angle 6 and the magnetic attraction portion of the spring member 8 are in non-contact with a gap C therebetween.

While the optical disk 11 is held, the spring pressing member 8 rotates while the end surface 6c of the burring of the support angle 6 is separated by a gap C, but between the end surface 6c and the magnet 7 and the spring pressing member 8. Since the magnetic attraction force interacts with each other, the turntable 4 and the clamper main body 5 firmly hold the disk 11, and the clamper main body 5 holds the rotor portion including the rotary shaft 3 via the disk 11 and the turntable 4. Since the motor is strongly pressed in the direction of the motor fixed angle 1 of the device, the rotor part on which the optical disk is mounted does not float above the stator part even at high speed rotation.

FIG. 5 is a diagram showing the holding characteristics of the disk 11 held between the turntable 4 and the clamper.
In FIG. 5, the X axis represents the thickness of the disk, and the Y axis represents the holding force of the disk. Further, D is the characteristic of the disk clamping mechanism by the conventional magnetic attraction force, and E is the characteristic of the disk clamping mechanism according to the present invention. The characteristic D of the conventional mechanism has a characteristic of an attenuation curve, and even if the thickness of the disk 11 is within the JIS standard, t
The holding force of this disk becomes (f2
-F1) changes greatly.

On the other hand, the end surface 6 of the burring of the support angle 6 in the disc clamp mechanism according to the present invention.
The magnetic attraction force that c and the magnet 7 act on the spring pressing member 8 changes the thickness of the optical disk by about 0.4 mm (J
Even if the thickness of the disk 11 sandwiched between the turntable 4 and the clamper 5 changes, the holding characteristic is the characteristic E because the vicinity of the characteristic that does not change even if the thickness range of the IS standard) is used. It becomes a straight line close to flat like.

For example, when the thickness of the disk 11 changes from t1 to t2 as described above, the coil spring 9 is further compressed, so that the amount of deflection is increased to (t2-t1) and the pressing force on the disk 11 is increased. The spring pressing member 8 in which the end face 6c of the burring of the support angle 6 and the magnet 7 are in a magnetic attraction relationship due to the increased force component is positioned as described above. (T2-t1) It is pushed further away. This is because the gap C is increased by (t2-t1), and as a result, the increased compression amount (t2-t1) of the coil spring 9 is canceled and the amount of deflection of the coil spring 9 remains substantially unchanged. Therefore, the pressing force of the clamper does not change when the thickness of the optical disk 11 is t1 and when it is t2, and the holding force of the sandwiched disk 11 is not changed substantially.

In this state, the tip of the rotary shaft 3 is inserted into the guide hole 5d of the clamper body 5 without play, so that the center of rotation of the clamper B itself is not displaced during the rotation of the turntable 4 and the disk 11. Does not happen. Further, since the ring-shaped magnet 7, the support angle 6, the spring pressing member 8 and the like are assembled on parallel planes, the disc 11 held on the turntable 4 can always be parallel to the optical pickup. The spring member that presses the clamper body 5 may be a coil spring or a leaf spring.

FIG. 6 is a perspective view showing the clamper body 5 from the side of the pressing portion 5b of the disk as a modification of the clamper according to the present invention. In FIG. 6, the pressing portion 5b of the clamper main body 5 is divided into a plurality of small portions 5f and large portions 5g by slit portions 5h. In such a configuration, when the mounting optical disk 11 is pressed, each of the divided parts of the clamper body 5 can be brought into contact independently,
It is possible to press the mounting optical disk 11 over the entire circumference without hitting it.

FIG. 7 is an explanatory cross-sectional view of a main part showing a disc clamp mechanism showing a modification of the embodiment of the present invention. FIG. 8 is a cross-sectional explanatory view of a main part showing the main part described in FIG. 7 in a further enlarged manner. This configuration is basically the same as in FIG.
A different point is that a magnet 17 for pressing the optical disk 11 is fixed to the inner peripheral side of a spring pressing member 18 formed in a cup shape. This function is the same as that described above, but there is an advantage that the size of the magnet 17 that presses the optical disk 11 can be reduced. Further, a flyhole effect utilizing the inertia of the magnet 17 can be obtained.

[0027]

As described above, according to the disk clamp mechanism of the present invention, when the disk of the clamper is chucked, the elastic force of the clamper acts against the magnetic attraction force of the magnetic attraction means. The disc can be pressed against the turntable to clamp the disc, and the rotor can be pressed against the stator when chucking the disc, so that the disc can rotate even if the thickness of the disc varies. Center deviation does not occur,
Further, it is possible to prevent the disc from floating even at high speed rotation.

Further, since it is not necessary to provide a ring-shaped magnet or a magnet for attraction between the rotor and the stator at the center of the turntable, leakage magnetic flux is reduced, magnetic noise is reduced, and the motor is made thinner. You can

[Brief description of drawings]

FIG. 1 is an explanatory cross-sectional view of essential parts showing a state before a disc is mounted according to an embodiment of the present invention.

FIG. 2 is a cross-sectional explanatory view of a main part showing a further enlarged view of the main part shown in FIG.

FIG. 3 is a cross-sectional explanatory view of essential parts showing when a disc is mounted according to the embodiment of the present invention.

FIG. 4 is a cross-sectional explanatory view of a main part showing the main part shown in FIG. 3 in a further enlarged manner.

FIG. 5 is an explanatory diagram showing the holding characteristics of the disc of the disc clamp mechanism according to the present invention and the conventional clamp mechanism.

FIG. 6 is a perspective view showing a modification of the clamper body according to the present invention.

FIG. 7 is an explanatory cross-sectional view of an essential part showing a modification of the embodiment of the present invention.

FIG. 8 is a cross-sectional explanatory view of a main part showing the main part shown in FIG. 7 in a further enlarged manner.

[Explanation of symbols]

1 Motor fixed angle 2 spindle motor 3 rotation axes 4 turntable 5 Clamper body 6 Support angle 7 magnet 8 Spring retainer 9 coil spring 10 stopper 11 optical disc 12 trays

Claims (5)

[Claims] 1. A disc clamp mechanism, comprising: a turntable fixed to a rotary shaft of a spindle motor; and a clamper supported in a suspended manner by a support angle. The disc clamp mechanism holds a disc by the turntable and the clamper. The clamper includes a clamper body facing the turntable, a spring pressing member including a magnetic metal part, and a spring member expanding the spring. The support angle includes a magnetic metal part, and a support facing the spring pressing member. A magnetic attraction means is provided at an angle position, and when chucking the disc, the elastic force of the spring member of the clamper acting against the magnetic attraction force of the magnetic attraction means pushes the disc against the turntable. And a disc clamping mechanism which clamps the disc. 2. The rotating shaft is provided on a rotor portion facing the stator portion of the spindle motor with an axial gap therebetween, and when the disk is chucked, the rotor portion is attached to the stator portion by the elastic force. The disk clamp mechanism according to claim 1, which presses. 3. The disk clamp mechanism according to claim 1, wherein the magnetic attraction means is a ring-shaped magnet fixed to the support angle. 4. The disk clamp mechanism according to claim 1, wherein the magnetic attraction means is a ring-shaped magnet fixed to the spring pressing member. 5. The spring member is formed of a coil spring or a leaf spring, and a spring constant is set so that the magnetic attraction means is in a non-contact attraction state when the turntable holds and holds the disk. The disk clamp mechanism according to any one of claims 1 to 4.