JP3751558B2 - Disc clamp mechanism - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a disk clamp mechanism used in a disk recording medium, particularly an optical disk recording / reproducing apparatus.
[0002]
[Prior art]
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, and information is written to the disk. Reading is in progress.
[0003]
However, if the optical disk placed on the turntable has a slight in-plane center-of-gravity shift or warp, the optical disk has been used at high speed in recent years, so the optical disk moves slightly on the turntable due to centrifugal force. The center of rotation has shifted or the optical disk itself has been lifted, which has caused a problem that the optical pickup has deviated from the track of the rotating optical disk, making it impossible to read or record information. .
[0004]
Conventionally, with respect to the rotation center deviation of the optical disk itself, a method of firmly holding the optical disk on the mounting surface of the turntable during rotation has been taken. As this method, a ring-shaped hole is provided in the center of the turntable, a ring-shaped magnet is provided in the hole, and an iron plate provided in a suspended manner on the support angle of the recording / reproducing apparatus with this magnet. The optical disk was firmly held in the direction of the disk mounting surface of the turntable by sandwiching the optical disk mounted by magnetically attracting the clamper made of the magnetic metal thin plate.
[0005]
Also, for the other optical disk itself floating, an attracting magnet is attached to the rotor side or stator side of the spindle motor, and a magnetic material is attached to the stator side or rotor side facing the gap to magnetically attract each other. Accordingly, a method has been adopted in which the rotor portion that fixes the turntable on which the optical disk is mounted does not float from the stator portion during rotation.
[0006]
[Problems to be solved by the invention]
However, the conventional method for preventing the rotation center deviation of the optical disk described above is that when a thick optical disk is placed, the magnetic attraction force between the ring-shaped magnet and the clamper that sandwich the disk may be significantly reduced. There is a problem of deviation of the rotation center of the optical disk.
[0007]
Conventionally, an optical disc is manufactured by attaching a stamper made on the basis of a master to a molding machine, and a transparent disc body is made by a resin molding process such as acrylic resin.
Thereafter, the disc main body is subjected to an aluminum reflective film vapor deposition step and a protective film coating step, and finally the title is displayed by label sticking or printing to complete the optical disc. However, since it is mass-produced through such a manufacturing process, it is inevitable that variations occur in each finished dimension. The thickness dimension that is particularly important for optical disks is according to JIS standards, for example, for CD-ROM optical disks, the thickness standard is 1.20 mm and the tolerance is +0.3 mm / −0.1 mm, and for DVD optical disks. The thickness standard specifies that the 1.20 mm tolerance is +0.3 mm / −0.06 mm.
[0008]
The thickness dimension of the optical disk produced by the manufacturing process as described above is not limited to the upper limit thickness and the lower limit value even if controlled within the JIS standard. The holding force by the magnetic attraction of the clamper may change significantly. This is in accordance with the damping characteristic that the force acting on the magnetic pole in Coulomb's law is inversely proportional to the square of the distance. When the magnetic attraction mechanism is set in a place where the characteristic changes drastically, the rotation center of the optical disk is shifted. The above-mentioned problem occurs remarkably.
[0009]
On the other hand, the above-described method for preventing the optical disk from being lifted has a problem that the number of parts of the attracting magnet and the magnetic material is increased and the assembly work is increased accordingly.
In addition, in such a component configuration, the structure of the spindle motor itself is large, and there is a problem that it cannot cope with the trend of thinning of the market.
Furthermore, in addition to the ring-shaped magnet, the addition of the attraction magnet increases the leakage magnetic flux, which also increases the magnetic noise.
[0010]
Therefore, the present invention solves the above-described problems, has a pressing force that prevents the center of rotation from shifting even if the thickness dimension of the optical disk fluctuates, and prevents the optical disk from being lifted even at high speed rotation. It is intended to provide a disk clamping mechanism that is low in noise and compatible with thin motors.
[0011]
[Means for Solving the Problems]
In order to solve the above problem, as in the invention described in claim 1, in the disk clamp mechanism of the turntable fixed to the rotating shaft of the spindle motor, a support angle made of a magnetic body having a burring; A magnet fixed to an outer peripheral side of the burring; a clamper having a stopper at an end of a cylindrical portion penetrating the burring of the support angle; and an optical disc pressing surface at the other end of the cylindrical portion; and the clamper A compressible spring member placed within the burring of the support angle, and a magnetic metal attached to the cylindrical portion of the clamper so as to be pressed by the spring member and stopped by the stopper A spring pressing member including a portion,
The thickness of the magnet is smaller than the burring height of the support angle,
When the turntable is not chucking the disc, the burring contacts the spring pressing member,
When the turntable chucks the disk, the magnetic force of the magnet and the spring constant of the spring member are set so that the burring is in a non-contact attractive state with the spring pressing member, This can be achieved by providing a disk clamping mechanism characterized in that the disk is clamped by being pressed against the turntable by the elastic force of the spring member acting against the magnetic attractive force of the magnet.
[0012]
Further, as in the invention according to claim 2, in the disc clamp mechanism of the turntable fixed to the rotating shaft of the spindle motor, a support angle made of a magnetic body having a through hole;
A clamper having a stopper at the end of the cylindrical portion passing through the through hole of the support angle, and an optical disc pressing surface at the other end of the cylindrical portion; and a through hole of the support angle on the outer periphery of the cylindrical portion of the clamper A compressible spring member placed in the hole; a cup-shaped spring pressing member including a magnetic metal portion mounted on the cylindrical portion of the clamper so as to be pressed by the spring member and stopped by the stopper; and the stopper And a magnet fixed to the inner periphery of the rising portion of the cup-shaped spring pressing member on the opposite side of
The thickness of the magnet is smaller than the height of the rising portion of the spring pressing member, and when the turntable does not chuck the disk, the rising portion of the spring pressing member is in contact with the support angle. ,
When the turntable chucks the disk, the magnetic force of the magnet and the spring constant of the spring member are set so that the rising portion of the spring pressing member is in a non-contact attractive state with the support angle. The disk can be achieved by including a disk clamping mechanism in which the disk is clamped by being pressed against the turntable by the elastic force of the spring member acting against the magnetic attraction force of the magnet. .
[0013]
Further, as in the invention described in claim 3, the spring member is formed by a coil spring or a leaf spring, and this can be achieved by providing the disk clamp mechanism according to claim 1 or 2.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
Next, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a cross-sectional explanatory view of a main part showing a state immediately before clamping a disc of a disc clamping mechanism showing an embodiment of the present invention. FIG. 2 is a cross-sectional view showing an enlarged main part described in FIG. 1 and 2, a turntable 4 is fixed to the end of a rotating shaft 3 of a spindle motor 2 fixed to a motor fixing angle 1 of the 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 was fixed to the recording / reproducing apparatus 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 portion facing the stator portion of the spindle motor 2. A support angle 6 is supported in a suspended manner.
[0015]
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 dimension smaller than the burring height dimension B. A ring-shaped magnet 7 magnetized in the axial direction of the rotary shaft 3 is fixed by press-fitting or bonding. The support angle 6 may be a non-magnetic material, and a 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 disk 11 is placed, and 4b is a non-slip member for the optical disk 11 placed.
[0016]
The clamper includes 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 molding resin having a disk-like elasticity. The spring pressing member 8 is made of a magnetic metal material such as an iron plate, and is inserted into the outer peripheral portion 5a of the end portion of the clamper body 5, and the outer diameter portion thereof is formed to be larger than the diameter of the outer periphery 6b of the burring of the support angle 6. ing. The spring pressing member 8, the stopper 10 fixed to the end of the clamper 5 so that it does not come off, and the convex surface of the spring pressing member 8 thus configured and the clamper body 5 opposite to the optical disc pressing surface 5 b. A compression type coil spring 9 having an inner diameter larger than the outer peripheral diameter portion 5a of the clamper body 5 and an outer diameter smaller than the diameter of the hole 6a of the support angle 6 is provided between 5c.
[0017]
In this state where the disk is not clamped, the end surface 6c of the burring of the support angle 6 is always in contact with the spring pressing member 8, and the pressing surface 5b of the clamper 5 has elasticity in the axial direction. The magnet 7 is set to a thickness dimension smaller than the burring height dimension B of the support angle 6, the gap between the spring pressing member 8 and the end 6c of the burring of the support angle 6 is set to a predetermined value, and the magnet Adjust the strength of the suction force. In the case where such adjustment of the magnetic attraction force is required, 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 that attracts the spring pressing member 8 is used. A thin non-magnetic material plate may be attached to adjust the thickness dimension.
[0018]
FIG. 3 is a cross-sectional explanatory view of a main part showing a state in which the disc of the disc clamp mechanism showing the embodiment of the present invention is clamped. FIG. 4 is a cross-sectional explanatory view of the main part showing the main part described in FIG. 3 further enlarged. When the turntable 4 approaches the clamper main body 5 side from the state of FIG. 1 described above, the turntable 4 places the optical disk 11, and the pressing surface 5 b of the clamper main body 5 begins to contact the disk 11, and then The coil spring 9 starts to be compressed, and the clamper body 5 starts pressing so as to hold the disk 11 with the turntable 4.
[0019]
Further, when the turntable 4 moves to a predetermined position, as shown in FIGS. 3 and 4, the clamper body 5 strongly compresses the coil spring 9, strongly presses the disk 11 placed on the turntable 4, and turns the turntable. 4 and the clamper 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 end face 6c of the burring of the support angle 6 and the magnetic attraction portion of the spring member 8 are in contact with each other with a gap C therebetween.
[0020]
In the state where the optical disk 11 is held, the end surface 6c of the burring having the support angle 6 rotates away from the end surface 6c by the gap C, but the end surface 6c and the magnet 7 and the spring pressing member 8 are magnetically attracted. Since the forces interact with each other, the turntable 4 and the clamper body 5 hold the disk 11 firmly, and the clamper body 5 uses the disk 11 and the turntable 4 to place the rotor portion including the rotating shaft 3 in the motor of this apparatus. Since it is strongly pressed in the direction of the fixed angle 1, the rotor portion on which the optical disk is placed does not rise above the stator portion even at high speed rotation.
[0021]
FIG. 5 is a diagram showing the holding characteristics of the disk 11 sandwiched between the turntable 4 and the clamper. In FIG. 5, the X-axis represents the disk thickness dimension, and the Y-axis represents the disk holding force. D shows the characteristics of the conventional disk clamping mechanism by magnetic attraction, and E shows the characteristics 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 when the thickness of the disk 11 is within the JIS standard, the holding force of the disk changes greatly as (f2-f1) from t1 to t2. To do.
[0022]
On the other hand, the magnetic attraction force acting on the spring pressing member 8 by the end face 6c of the burring of the support angle 6 and the magnet 7 in the disc clamping mechanism according to the present invention changes the thickness of the optical disc by about 0.4 mm ( Since the vicinity of the characteristic that does not change even when the thickness dimension of the JIS standard is used is used, even if the thickness of the disk 11 sandwiched between the turntable 4 and the clamper 5 is changed, the holding characteristic is the characteristic E. It becomes a straight line that is close to flat.
[0023]
For example, when the thickness of the disk 11 is changed 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 against the disk 11 is increased. However, 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 is configured as described above, so that the position (t2- t1) It is pushed away further. This is because the gap C is increased by about (t2-t1), and as a result, the compression increase (t2-t1) of the coil spring 9 is canceled and the deflection amount of the coil spring 9 is not substantially changed. Therefore, the pressing force by the clamper when the thickness of the optical disk 11 is t1 and t2 does not change, and the holding force of the sandwiched disk 11 is almost the same.
[0024]
Further, in this state, the tip of the rotary shaft 3 is fitted into the guide hole 5d of the clamper body 5 without any backlash, so that the center of rotation of the clamper B itself does not occur while the turntable 4 and the disk 11 are rotating.
Further, since the ring-shaped magnet 7, the support angle 6, the spring pressing member 8 and the like are assembled in parallel planes, the disk 11 held on the turntable 4 can always cope with the optical pickup in parallel.
The spring member that presses the clamper body 5 may be a leaf spring in addition to the coil spring.
[0025]
FIG. 6 is a perspective view showing the clamper main body 5 as viewed from the pressing portion 5b side of the disk as a modification of the clamper according to the present invention. In FIG. 6, a plurality of pressing portions 5b of the clamper body 5 are divided into a small portion 5f and a large portion 5g by a slit portion 5h. In such a configuration, when the loaded optical disk 11 is pressed, each divided portion of the clamper main body 5 can be brought into contact with each other, so that the loaded optical disk 11 is pressed over the entire circumference without causing a single contact. be able to.
[0026]
FIG. 7 is a cross-sectional explanatory view of a main part showing a disk clamp mechanism showing a modification of the embodiment of the present invention. FIG. 8 is an explanatory cross-sectional view of a main part showing the main part described in FIG. 7 further enlarged. This configuration is basically the same as that shown in FIG. 1, except that a magnet 17 that presses the optical disk 11 has a rising portion 18a around the inner side of a spring presser member 18 formed in a cup shape. It is fixed. Although this function is the same as that described above, 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 also be obtained.
[0027]
【The invention's effect】
As described above, according to the disk clamp mechanism of the present invention, when the disk of the clamper is chucked, the disk is pressed against the turntable by the elastic force of the clamper acting against the magnetic attraction force of the magnet. The disc can be clamped, and when the disc is chucked, the rotor portion can be pressed against the stator portion, and even if the disc thickness varies, the center of rotation does not occur, Further, it is possible to prevent the disc from floating even at high speed rotation.
[0028]
Further, since there is no need to provide a ring-shaped magnet or a magnet for attraction between the rotor and the stator at the center of the turntable, the leakage magnetic flux is reduced, magnetic noise is reduced, and the motor can be made thinner.
[Brief description of the drawings]
[0029]
FIG. 1 is an explanatory cross-sectional view of a main part showing a disk before mounting in an embodiment of the present invention.
FIG. 2 is a cross-sectional explanatory view of a main part showing the main part shown in FIG. 1 further enlarged.
FIG. 3 is an explanatory cross-sectional view of a main part showing when a disc is loaded in the embodiment of the present invention.
4 is a cross-sectional explanatory diagram of a main part, further illustrating the main part shown in FIG. 3; FIG.
FIG. 5 is an explanatory diagram showing the disc holding characteristics of the disc clamping mechanism according to the present invention and the conventional clamping 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 a relevant part showing a modification of the embodiment of the present invention.
FIG. 8 is a cross-sectional explanatory view of main parts further showing the main parts shown in FIG.
[Explanation of symbols]
[0030]
DESCRIPTION OF SYMBOLS 1 Motor fixed angle 2 Spindle motor 3 Rotating shaft 4 Turntable 5 Clamper body 6 Support angle 7 Magnet 8 Spring pressing member 9 Coil spring 10 Stopper 11 Optical disk 12 Tray

Claims (3)

In a disc clamp mechanism of a turntable fixed to a rotating shaft of a spindle motor, a support angle composed of a magnetic body having a burring, a magnet fixed to the outer peripheral side of the burring, and a piercing through the burring of the support angle A clamper having a stopper at the end of the cylindrical part and having an optical disc pressing surface at the other end of the cylindrical part, and a compressible which is placed on the outer periphery of the cylindrical part of the clamper and placed in the burring of the support angle An elastic spring member, and a spring pressing member including a magnetic metal portion attached to the cylindrical portion of the clamper so as to be pressed by the spring member and stopped by the stopper,
  The thickness of the magnet is smaller than the burring height of the support angle,
  When the turntable is not chucking the disc, the burring contacts the spring pressing member,
  When the turntable chucks the disk, the magnetic force of the magnet and the spring constant of the spring member are set so that the burring is in a non-contact attractive state with the spring pressing member, A disc clamping mechanism, wherein the disc is clamped by being pressed against the turntable by an elastic force of the spring member acting against a magnetic attraction force of a magnet. In the disc clamp mechanism of the turntable fixed to the rotating shaft of the spindle motor, a support angle composed of a magnetic body having a through hole,
A clamper having a stopper at the end of the cylindrical portion passing through the through hole of the support angle, and an optical disc pressing surface at the other end of the cylindrical portion; and a through hole of the support angle on the outer periphery of the cylindrical portion of the clamper A compressible spring member placed in the hole; a cup-shaped spring pressing member including a magnetic metal portion mounted on the cylindrical portion of the clamper so as to be pressed by the spring member and stopped by the stopper; and the stopper And a magnet fixed to the inner periphery of the rising portion of the cup-shaped spring pressing member on the opposite side of
  The thickness of the magnet is smaller than the height of the rising portion of the spring pressing member, and when the turntable does not chuck the disk, the rising portion of the spring pressing member is in contact with the support angle. ,
  When the turntable chucks the disk, the magnetic force of the magnet and the spring constant of the spring member are set so that the rising portion of the spring pressing member is in a non-contact attractive state with the support angle. The disk is clamped by the disk being pressed against the turntable by the elastic force of the spring member acting against the magnetic attraction force of the magnet.   3. The disc clamping mechanism according to claim 1, wherein the spring member is formed of a coil spring or a plate spring.

Images