JP3744198B2 - Disk drive device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a novel disk drive device. Specifically, in a disk drive device in which an automatic alignment mechanism for eliminating imbalance in the recording medium disk is provided in a rotation drive unit that rotates the recording medium disk, the automatic alignment mechanism reliably exhibits its function. It is related to the technology that makes it possible.
[0002]
[Prior art]
5 and 6 schematically show an example of a conventional disk drive device.
[0003]
The disk drive device a includes a mechanical chassis b, and necessary members and parts are mounted on the mechanical chassis b.
[0004]
A spindle motor d that rotates the turntable c is disposed at one end of the mechanical chassis b, and the optical disk e is supported on the turntable c and rotated. On the mechanical chassis b, an optical pickup g that is moved in the radial direction of the optical disk e supported by the turntable c by a thread motor f is disposed. In this way, necessary members and parts are arranged on the mechanical chassis b to constitute the drive unit h, and the drive unit h is attached to the base chassis j via the elastic bodies i, i,. This is to prevent the vibration generated by the optical disk having an imbalance, that is, when the optical disk whose center of gravity is not located at the center rotates at high speed from being transmitted to the outside of the disk drive device a.
[0005]
The spindle motor d has an automatic alignment mechanism.
[0006]
The automatic alignment mechanism of the spindle motor d is explained by the automatic balancing device of Thearl. For details on the automatic balancing apparatus of Thear, refer to “Mechanical Mechanics” (March 1982) P146, 147 published by Rigaku Corporation.
[0007]
The principle and function of Theearl's automatic balancing device k will be briefly described with reference to FIG. The automatic balancing device k of Thear is composed of a holder l having an annular race portion and a plurality of balls m and m that can freely move on the holder l.
In the state where the unbalanced optical disk e is supported on the turntable c, the optical disk e is at a frequency higher than the resonance frequency of the vibration system composed of the drive unit h and the elastic bodies i, i,. When rotating, the drive unit h vibrates with a delay of about 180 ° from the unbalanced phase of the optical disk e. Since the balls m and m automatically move in the direction in which the drive unit h vibrates, as a result, the balls m and m move in an opposite phase to the unbalance of the optical disk e, and the operation principle is that the balance is automatically restored. .
[0008]
For example, when the unbalanced optical disk e is rotated and vibration is generated in the drive unit h, there is a fear that the signal related to the optical disk e may not be sufficiently read and written, and the vibration is caused by the disk drive device a. When transmitted to the outside, the spindle motor d may adversely affect the surroundings, such as causing a peripheral device such as a hard disk drive to vibrate. By providing this, such adverse effects are prevented.
[0009]
[Problems to be solved by the invention]
By the way, in the conventional disk drive apparatus a, the operation of the automatic alignment mechanism becomes unstable, and there is a problem that the performance cannot be fully exhibited.
[0010]
The center of gravity G of the drive unit h is determined by the arrangement of the optical pickup g and the sled motor f, the shape of the mechanical chassis b, and the like. In the drive unit h, the center of gravity G from the various elements is obtained from the rotation center of the optical disk e, that is, from the center of the rotation axis of the spindle motor d, as shown in FIG. It is shifted in the direction in which the thread motor f is arranged.
[0011]
When the center of gravity G of the drive unit h is deviated from the rotation center of the optical disk e, the vibration caused by the unbalance of the optical disk e, that is, the vibration shape of the shaft is a two-degree-of-freedom vibration of parallel vibration and rotational vibration. Since this is different in each direction of the drive unit h, it becomes elliptical as shown by n in FIG.
[0012]
If the shaft vibrates in an elliptical shape, the operation of the automatic centering mechanism becomes unstable, and the performance cannot be fully exhibited.
[0013]
Therefore, an object of the present invention is to bring the center of gravity of the drive unit closer to the rotation center of the recording medium disk so that the automatic alignment mechanism can sufficiently exhibit its performance.
[0014]
[Means for Solving the Problems]
In order to solve the above-described problems, the disk drive apparatus of the present invention moves to a rotary drive unit including a spindle motor that rotates a turntable that supports a recording medium disk, and a holder that rotates together with the rotor unit of the spindle motor. An automatic centering mechanism having a free balance member is provided, and a counterweight is disposed on the stator portion of the spindle motor, whereby the center of gravity of the drive unit is made coincident with or close to the rotation center of the spindle motor. .
[0015]
Therefore, in the disk drive apparatus of the present invention, the center of gravity of the drive unit coincides with or is close to the rotation center of the spindle motor, so that the vibration locus of the rotation center of the recording medium disk can be brought close to a circular orbit and the drive unit vibrates. The force generated by this is stabilized in any phase direction, and the balance member can quickly move to the position where the unbalance is eliminated, that is, the equilibrium position.
[0016]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of a disk drive device according to the present invention will be described below with reference to the accompanying drawings.
[0017]
In the illustrated embodiment, the present invention is applied to an optical disc drive apparatus for recording and / or reproducing an optical disc.
[0018]
The optical disk drive apparatus 1 is configured by attaching a drive unit 3 having required members and parts mounted on a mechanical chassis 2 to a base chassis 5 via elastic bodies (dampers) 4, 4.
[0019]
A spindle motor 6 is fixed to one end of the mechanical chassis 2 via a stator substrate 7.
[0020]
A cylindrical shaft support portion 8 is fixed to the stator substrate 7, and a spindle shaft 9 is rotatably supported by the shaft support portion 8 via bearings 10 and 10. The lower end of the spindle shaft 9 is supported by a thrust bearing 11 attached to the shaft support portion 8. A stator coil 12 is disposed and fixed to the stator substrate 7 so as to surround the shaft support portion 8.
[0021]
A rotor yoke 13, which is shaped like a deep dish with a magnetic material, is fixed to the spindle shaft 9 so as to surround the outside of the stator coil 12 with its peripheral wall portion. The rotor magnet 14 is fixed so as to face the motor 12. Accordingly, when the stator coil 12 is energized, the rotor yoke 13 rotates, and the spindle shaft 9 to which the rotor yoke 13 is fixed is rotated.
[0022]
A turntable 15 is fixed to the upper end portion of the spindle shaft 9.
[0023]
An automatic alignment mechanism 16 is provided between the rotor yoke 13 and the turntable 15. The automatic centering mechanism 16 includes a ring-shaped storage chamber 17 and a plurality of balance balls 18 movably disposed in the storage chamber 17. The storage chamber 17 is formed by a plate-like member fixed to the spindle shaft 9, and the upper surface of the storage chamber 17 is closed by a turntable 15.
[0024]
A counterweight 19 is attached to the stator substrate 7. As the material of the counterweight 19, it is preferable to use a laminate of steel plates or a sintered metal having a high density and a high weight compared to the volume.
[0025]
An optical pickup 20 is supported by guides 22 and 23 so that the optical pickup 20 can move in the radial direction of the optical disk 21 supported on the turntable 15 at a portion of the mechanical chassis 2 behind the portion where the spindle motor 6 is disposed. Yes.
[0026]
The optical pickup 20 is provided with a rack gear 24, and the rack gear 24 is sent by a pinion gear 26 that is rotated by a thread motor 25 fixed to the mechanical chassis 2, whereby the optical pickup 20 is guided to the guides 22 and 23. The optical disk 21 supported on the turntable 15 moves in the radial direction.
[0027]
In addition to the above, necessary members and parts are mounted on the mechanical chassis 2 to constitute the drive unit 3.
[0028]
Accordingly, the optical disk 21 supported on the turntable 15 is rotated together with the turntable 15 as the spindle motor 6 is driven, and the optical pickup 20 moves in the radial direction of the optical disk 21 while the optical disk 21 moves. Record and / or play back signals.
[0029]
At this time, when the optical disk 21 supported on the turntable 15 is unbalanced and vibration occurs, the balance ball 18 of the automatic alignment mechanism 16 moves to a position where the unbalance is eliminated. Thus, the vibration is eliminated or reduced.
[0030]
As described above, in the optical disc drive apparatus 1 according to the present invention, since the counterweight 19 is disposed on the stator substrate 7 of the spindle motor 6, the center of gravity G 'of the drive unit 3 is shown in FIG. As shown in FIG. 4, since it coincides with or is close to the rotation center of the spindle shaft 9 of the spindle motor 6, the vibration caused by the unbalance becomes close to a circle. And surely done.
[0031]
The reason will be described with reference to FIG.
[0032]
A centrifugal force Fr = mrω ² generated when the storage chamber 17 rotates and a force Fe = meω ² generated when the drive unit 3 vibrates are applied to the balance ball 18.
[0033]
Here, m is the mass of the balance sphere 18, r is the revolution radius when the balance sphere 18 is on the storage chamber 17, e is the amplitude of vibration of the drive unit 3, and ω is the rotational speed of the spindle motor 6.
[0034]
If the spindle motor 6 only rotates on the balance ball 18, only the centrifugal force Fr acts, and the balance ball 18 is only pressed against the outer peripheral surface of the storage chamber 17, but the drive unit 3 vibrates. , Fe acts to generate a resultant force F, which causes a declination α, and the balance ball 18 moves in the circumferential direction to adjust the balance.
[0035]
However, in reality, there is a rolling friction coefficient μ between the balance sphere 18 and the storage chamber 17, so the condition for the balance sphere 18 to move must be μ <tanα.
[0036]
Here, α = sin ⁻¹ (Fe sin θ / F) (θ is an angle formed by Fr and Fe).
[0037]
Accordingly, the larger the Fe generated by the vibration of the drive unit 3 is, the larger the allowable rolling friction coefficient μ is.
[0038]
Therefore, if the center of gravity G of the drive unit h is greatly deviated from the center of rotation of the optical disk e and the axis vibrates in the elliptical orbit n as in the prior art, Fe increases in the major axis direction of the ellipse and The rolling friction coefficient becomes large and the ball m is easy to move, and hence the automatic balancing device k is easy to operate. However, since Fe becomes small in the short axis direction, the allowable rolling friction coefficient becomes small, and the ball m It is difficult to move and the automatic balancing device k is difficult to operate.
[0039]
On the other hand, in the optical disc drive apparatus 1, the counterweight 19 is disposed on the stator substrate 7 that is the stator member of the spindle motor 6, and the center of gravity G ′ of the drive unit 3 is set to the rotation center of the optical disc 21, that is, the spindle. Since the center of the shaft 9 coincides with or is close to the center, the vibration path of the rotation center of the optical disk 21 can be brought closer to the circular path 27 from the elliptical path, and the Fe is stable in any phase direction, and the automatic alignment mechanism 16 Becomes easier to operate.
[0040]
In order to bring out the above-described effect more reliably, it is preferable that the counterweight 19 is disposed on the opposite side of the position where the optical pickup 20 and the sled motor 25 are disposed with the spindle shaft 9 interposed therebetween.
[0041]
Further, the number of counterweights is not limited to one, and a plurality of counterweights may be provided.
[0042]
In the above embodiment, the automatic alignment mechanism 16 includes a ring-shaped storage chamber 17 and a plurality of balance balls 18 movably disposed in the storage chamber 17. The form of the alignment mechanism is not limited to this, and if there is vibration based on the eccentric gravity center of the rotating body, it may have a balance member that moves and balances the eccentric gravity center. Any configuration may be used.
[0043]
Furthermore, although the said embodiment showed what applied this invention to the optical disk drive device which records and / or reproduces | regenerates an optical disk, the scope of this invention is not limited to such a thing, The present invention can be widely applied to disk drive devices that use other recording medium disks.
[0044]
【The invention's effect】
As is apparent from the above description, the disk drive device of the present invention moves in the radial direction of the recording medium disk supported by the spindle motor that rotates the turntable that supports the recording medium disk on the mechanical chassis, and the turntable. A disk drive device in which a drive unit having a pickup or the like for reproducing and / or recording a signal on a recording medium disk is supported on a base chassis via an elastic body, and includes a rotation driving unit including the spindle motor. Is provided with a holder that rotates together with the rotor portion of the spindle motor and a self-aligning mechanism that includes a balance member that can move within the holder, and a counterweight is disposed on the stator portion of the spindle motor, whereby the drive unit Spindle mode center of gravity Characterized in that by matching or close to the center of rotation.
[0045]
Therefore, in the disk drive apparatus of the present invention, the center of gravity of the drive unit coincides with or is close to the rotation center of the spindle motor, so that the vibration locus of the rotation center of the recording medium disk can be brought close to a circular orbit, and the drive unit The force generated by this is stabilized in any phase direction, and the balance member can quickly move to the position where the unbalance is eliminated, that is, the equilibrium position. Thus, the automatic alignment mechanism can reliably exhibit its function.
[0046]
Further, in the invention described in claim 2, the holder of the automatic alignment mechanism is a ring-shaped storage chamber, and the balance member is movably disposed in the storage chamber. Therefore, the automatic alignment mechanism can be easily configured.
It should be noted that the shapes and structures of the respective parts shown in the above-described embodiments are merely examples of implementations in carrying out the present invention, and these limit the technical scope of the present invention. It should not be interpreted in a general way.
[Brief description of the drawings]
FIG. 1 shows an embodiment of a disk drive apparatus according to the present invention together with FIGS. 2 to 4, and this figure is a perspective view showing an outline of the disk drive apparatus.
FIG. 2 is an enlarged vertical sectional view of a rotation driving unit.
FIG. 3 is a schematic plan view.
FIG. 4 is a diagram for explaining the influence of a vibration locus on an automatic alignment mechanism.
FIG. 5 shows a conventional disk drive device together with FIG. 6, and is a schematic perspective view.
FIG. 6 is a schematic plan view.
FIG. 7 is a diagram for explaining the principle of Theearl's automatic balancing apparatus.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Optical disk drive device (disk drive device), 2 ... Mechanical chassis, 3 ... Drive unit, 6 ... Spindle motor, 15 ... Turntable, 16 ... Automatic alignment mechanism, 17 ... Storage chamber (holder), 18 ... Balance ball ( Balance member), 19 ... counter weight, 20 ... optical pickup (pickup), 21 ... optical disc, G '... center of gravity of drive unit

Claims (2)

A spindle motor that rotates a turntable that supports a recording medium disk on a mechanical chassis, a pickup that moves in the radial direction of the recording medium disk that is supported by the turntable, and reproduces and / or records signals on the recording medium disk A disk drive device comprising: a drive unit provided with a base chassis supported via an elastic body;
The rotary drive unit including the spindle motor is provided with an automatic alignment mechanism including a holder that rotates together with the rotor unit of the spindle motor and a balance member that is movable in the holder.
A counterweight is arranged on the stator part of the spindle motor,
Thus, the disk drive device characterized in that the center of gravity of the drive unit coincides with or is close to the rotation center of the spindle motor. 2. The disk according to claim 1, wherein the holder of the automatic alignment mechanism is a ring-shaped storage chamber, and the balance member is a plurality of balance balls movably disposed in the storage chamber. Drive device.

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