KR19990002693A - Vibration absorber of disk driver - Google Patents

Abstract

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a vibration absorbing device for eliminating vibration and noise caused by rotation of a disk.

A vibration absorber of a disk drive according to the present invention comprises a mechanism base on which a spindle motor and an optical pickup are mounted, at least one vibration absorber located at one side of the mechanism base and suppressing vibration of the mechanism base, And a mass correction means.

The vibration absorbing device of the disk driver of the present invention has the advantage that vibration and noise can be suppressed by making the center of gravity coincide with the center of rotation.

Description

Vibration absorber of disk driver

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a disk recording / reproducing apparatus, and more particularly, to a vibration absorbing device that eliminates vibration and noise caused by rotation of a disk.

Description of the Related Art [0002] In recent years, a recording medium of a compact disc (hereinafter referred to as CD) and a recording medium of a digital versatile disc (hereinafter referred to as DVD) / Reproduction apparatuses are required to increase the transmission speed. Accordingly, the rotation speed of the disk is increased in proportion to the transmission speed. At this time, when the center of rotation and the center of mass do not coincide, the disk driver deck inevitably causes vibration and noise problems, especially in the high frequency mode. At high speed rotation of the disk whose center of rotation is not coincident with the center of mass, centrifugal force due to mass unbalance causes vibration of the supporting part of the rotating body. Since the centrifugal force is proportional to the square of the rotation speed (ω), the vibration becomes serious as the rotational speed of the disk increases. It is impossible to completely eliminate the mass unbalance in the manufacturing process of the recording medium and it is inevitable that the mass unbalance due to the rotation of the disk is unavoidably caused due to the deviation when the recording medium is mounted on the disk driver Problems arise. In the case of a disk recording / reproducing apparatus used in a personal computer, vibration of adjacent peripheral devices may cause vibration of the disk recording / reproducing apparatus. The influence of such an external vibration source has become a serious problem in a disk recording / reproducing apparatus developed in portable devices and automotive devices.

A conventional disc recording / reproducing apparatus is provided with an anti-vibration rubber between an arbitrary fixed portion of a driver set and a mechanism base to suppress vibration of the mechanism base relative to an external vibration source.

Hereinafter, a vibration absorber of a conventional disk driver will be described with reference to FIGS. 1 and 2. FIG.

1 (A), 1 (B) and 1 (C), a conventional vibration absorbing device for a disk drive includes a mechanism base 10 in which a spindle motor 2 and an optical pickup 4 are assembled, (6) provided between the fixed portion (8) of the driver set (10) and the driver set (10) and suppressing the vibration of the mechanism base (10) from an external vibration source.

The spindle motor 2 has a turntable 2a on which a disk is seated, and rotates the disk 1 by the driving force of the motor. The optical pickup 4 includes an objective lens 4a for condensing a light beam from the laser diode light source on the information recording surface of the disc 1 and directing the reflected light beam from the information recording surface toward the photodetector so that a light beam from the information recording surface Photoelectric conversion and reproduction, or information is recorded on the information recording surface. The spindle motor 2 is fixed to the mechanism base 10 and the optical pickup 4 is installed in the mechanism base 10 so that the optical pickup 4 can be transported in the radial direction of the disk. The objective lens 4a of the optical pickup 4 is driven vertically and laterally by a Lorentz force generated in the magnetic circuit. The up and down direction of the flow of the objective lens 4a indicates the focusing direction in which the light beam from the objective lens 4a is in the depth of focus of the signal track of the disc 1 and the left and right direction shows the focusing direction of the light beam from the objective lens 4a Refers to the tracking direction in which the center of the signal track of the disc 1 is followed. Accordingly, the transporting direction of the optical pickup 4 is hereinafter referred to as a tracking direction for the sake of convenience. In the disk drive, the centrifugal force F due to mass unbalance occurs in the radial direction of the disk 1. This centrifugal force is transmitted to the mechanism base 10 through the spindle motor 2. [ At this time, the centrifugal force due to mass unbalance causes a discrepancy between the center of rotation of the disk and the center of mass, so that the mechanism base 10 vibrates in the radial direction of the disk 1. In order to eliminate such vibration, there is a method of fixing the mechanism base 10 to the driver set 8. In this case, when vibration is applied to the driver set 8 by a vibration source that generates vibrations from the outside of the driver deck, the vibration is transmitted to the mechanism base 10 as it is and the optical pickup 4, which is located in the mechanism base 10, . The objective lens 4a vibrates in the focusing or tracking direction as the optical pickup vibrates, causing the optical pickup 4 to reproduce or record the signal recorded on the disc 1 inaccurately. In the case of a PC, vibration is inevitably generated due to mounting of a disk driver and other peripherals. Particularly, in developing a disk driver for a car and a portable disk driver, the excitation source from the outside acts relatively more on the driver set.

For the purpose of solving such a problem, a vibration proof material is provided between the mechanism base 10 and the fixed portion of the driver set 8 to lower the natural frequency with respect to the vibration externally applied, so that the objective lens 4a vibrates It is essential to prevent the Thus, the vibration-proof rubber 6 is positioned between the fixed base of the mechanism base 10 and the driver set 8.

2 showing a mathematical model thereof, mathematical modeling of a vibration system according to a conventional disk driver is performed by using a mass of a vibrating body (a mechanism base provided with a spindle motor, an optical pickup, etc.) having a centrifugal force F and vibrating with Fsinωt a displacement x1 of m1 due to mass unbalance, a spring constant k1 of the vibration-proof rubber 6 located between the mechanism base 10 and the fixed portion 8 of the set, damping (hereinafter referred to as damping) It is modeled as a constant c1. m1, x1, k1, and c1 are non-dimensional variables in the vibration system. The vibration-proof rubber 6 is represented by a spring constant k1 and a damping constant c1 in the mathematical modeling of the vibration system. The displacement x1 of the mass m1 of the mechanism base 10 becomes an excitation by the centrifugal force F generated as the disk rotates. When the characteristic frequency of the vibration system that ω ² _n = k1 / m1, the result of the analysis is shown in equation (1).

[Equation 1]

Here, the magnitude of the damping factor? Is? 1 and is defined as the ratio r =? /? _N of the rotational frequency (?) Of the disk to the natural frequency (? _N ).

In this case, if the mass unbalance is m _e and its position is e from the center of mass, the centrifugal force F = m _{e e} ω ² . Substituting this into Equation 1, Equation 2 is obtained.

&Quot; (2) "

In the recording / reproducing medium according to the rotation of the disk, the vibration of the optical pickup 4 can be reduced by lowering the natural frequency to the vibration source from the outside. In this case, the ratio r of the rotation frequency (?) Of the disk to the natural frequency (? _N ) is r 1, . Accordingly, when the rotational frequency (ω) of the disk increases, mass unbalance and displacement of the mass m1 of the mechanism base 10 in proportion to the position e occur. The force transmitted to the outside of the mechanism base 10 is proportional to the acceleration of the mechanism base 10 and this acceleration becomes? ² X1, so that the driver set 8 having the driver set 8 proportional to the square of the rotational speed of the disk A force is generated. This force causes the driver set 8 to vibrate and generate noise. As the rotational speed of the disk is increased in proportion to the information transfer rate, suppression of vibration of the mechanism base 10 due to high-speed rotation of the disk is an important requirement for enhancing the performance and reliability of the disk driver. However, although the vibration absorbing device of the conventional disk drive has implemented a vibration system that places the vibration-proof rubber that suppresses the vibration of the mechanism base from the outer circumferential vibration source between the fixing portion and the mechanism base, ≪ / RTI >

SUMMARY OF THE INVENTION It is, therefore, an object of the present invention to provide a vibration absorbing device for a disk driver capable of suppressing vibration and noise by making the center of gravity and the center of rotation coincide.

It is another object of the present invention to provide a vibration absorbing device for a disk driver capable of precisely recording / reproducing by making the center of gravity and the center of rotation coincide with each other to suppress the vibration of the optical pickup.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic vertical sectional view and plan view of a disk drive using a conventional vibration absorbing device. FIG.

2 is a mathematical modeling diagram for explaining a vibration meter of a conventional disk driver;

3 is a schematic vertical sectional view and plan view of a disk driver to which a vibration absorbing device according to an embodiment of the present invention is applied.

FIG. 4 is a mathematical modeling diagram for explaining the vibration system of the disk driver of FIG. 3;

5 is a vertical sectional view and a plan view for explaining a vibration absorbing device according to an embodiment of the present invention.

6 is a vertical sectional view and a plan view for explaining a vibration absorbing device according to another embodiment of the present invention.

Description of the Related Art [0002]

1: Disk 2: Spindle motor

2a: Turntable 4: Optical pickup

4a: objective lens 6: anti-vibration rubber

8: Fixing part of driver set 10: Mechanism base

22, 32: mass balance correcting member 24, 34:

26: screw 26a, 28a: boss

26b, 28b: vertical fixing piece

In order to achieve the above object, a vibration absorber of a disk drive according to the present invention comprises a mechanism base on which a spindle motor and an optical pickup are mounted, a mechanism base disposed on one side of the mechanism base, And at least one mass correction means for suppressing the vibration of the motor.

Other objects and advantages of the present invention will become apparent from the following description of embodiments with reference to the accompanying drawings.

Hereinafter, preferred embodiments of the present invention will be described with reference to FIGS. 3 to 6. FIG.

3 is a schematic plan view and a side view showing a disk drive employing the vibration absorber according to the present invention.

3 (A), 3 (B) and 3 (C), a vibration absorber of a disk drive according to the present invention comprises a mechanism base 10 in which a spindle motor 2 and an optical pickup 4 are assembled, An anti-vibration rubber 6 positioned between the base 10 and the fixed portion of the driver set 10 so as to suppress the vibration of the mechanism base 10 from an external vibration source, And a mass compensating body (22) positioned so as not to be supported by an arbitrary fixed portion so as to suppress the vibration of the mechanism base (10) irrespective of the rotational speed of the disk (1).

The spindle motor 2 and the optical pickup 4 are positioned in the mechanism base 10 and the vibration of the mechanism base 10 is suppressed from the external vibration source by the vibration proof rubber 6, The vibration is suppressed regardless of the rotational speed of the disk 1. Fig.

An elastic body 24 is provided on one side of the mass corrector 22 and is fixed on the mechanism base 10 with an arbitrary spring constant k2 and an elastic modulus c2.

4 shows a mathematical modeling of a vibration absorber of a disk driver according to the present invention.

4, the mathematical modeling of the vibration absorber of the disk driver according to the present invention is performed by using the mass m1 of a vibrating body (a mechanism base provided with a spindle motor, an optical pickup, etc.) vibrating with Fsinωt with a centrifugal force F, A mass compensating body 22 connected in series to m1 by a spring constant k1 and a damping constant c1 of the discharge rubber 6 located between m1 and the fixed portion and a spring constant k2 and c2 by a mass unbalance displacement x1, Of the mass m2. m1, x1, k1, c1, m2, x2, k2, c2 are non-dimensional variables in the vibration system.

The displacement x1 of the mass m1 of the mechanism base 10 becomes an excitation by the centrifugal force F generated as the disk rotates at the rotational speed of [omega]. Mathematically analyzing such a vibration system is expressed by Equation (3).

&Quot; (3) "

Here, if the attenuation constant c2 = 0, Equation (3) becomes Equation (4).

&Quot; (4) "

In the equation (4), when k2 -? ² m2 = 0, x1 = 0. That is, when? ² = k2 / m2, no vibration occurs in the disk drive regardless of the rotational speed. In the conventional vibration absorbing device without the mass correcting member 22, the displacement x1 of the mechanism base 10 is set to be larger than the natural frequency, And the excitation force (acceleration) transmitted to the driver set 8 increases in proportion to the square of the rotational speed of the disk at? ² X1, causing vibration and noise problems when the disk is rotated at high speed. On the other hand, in the vibration absorber according to the present invention, the mass corrector 22 is installed on any one side of the mechanism base 10 so that no vibration occurs regardless of the rotational speed of the disk.

In recent years, a disk driver using a recent optical disk as a recording medium has been in the general trend to rotate the disk at a constant speed in order to increase the data transfer rate. In the case where the disk rotates at a constant speed, it is not necessary to provide a separate device for matching the center of gravity with the center of rotation of the vibration system due to the vibration absorbing device according to the present invention. In the vibration-absorbing device of the disk driver according to the present invention, vibration due to rotation of the disk is not transmitted to the outside, so that vibration and noise are not generated. Further, when the vibration absorbing apparatus according to the present invention is applied to a recording / reproducing apparatus, since the mechanism base does not vibrate to the vibration due to the rotation of the disk, stable recording / reproduction of the optical pickup located in the mechanism base can be performed. This will be described in detail with reference to FIGS. 5 and 6 according to an embodiment of the present invention.

5 is a schematic vertical sectional view and a side view of a vibration absorber of a disk drive according to an embodiment of the present invention.

5A and 5B, a vibration absorber of a disk drive according to the present invention includes a boss 26a extended at a predetermined height at an arbitrary point on the mechanism base 10, (24), and a cylindrical mass compensating body (22) located on the outer peripheral surface of the elastic body (24) and having an elastic body (24) fitted in the inner diameter.

The elastic body 24 is fitted to the outer peripheral surface of the boss 26a of the mechanism base 10 and is fixed to the lower end surface of the elastic body 24 and the mass correction body 22 in a cylindrical vertical fixing Piece 26b is located. The screw 26 is fitted through the inner diameter of the vertical fixing piece 26b and the inner diameter of the boss 26a to fix the elastic body 24 and the mass fixing body 22 and the vertical fixing piece 26b. Then, the mass correction body 22 is fixed in the vertical direction of the mechanism base 10, and the vibration of the mass correction body 22 is controlled by the elastic body 22 in the horizontal direction. If the rotational frequency of the disk, the elastic modulus of the elastic material, and the mass of the mass corrector are set to appropriate values, the vibration in the horizontal direction can be suppressed regardless of the rotational frequency of the disk. The height of the mass correction body 22 in the vertical direction is set to be lower than the height of the elastic body 24. Thus, the cylindrical mass compensating body 22 and the elastic body 24 can be usefully applied to suppress vibration in the radial direction of all disks.

6 is a schematic vertical sectional view and a side view of a vibration absorber of a disk driver according to another embodiment of the present invention.

6, the vibration absorber of the disk drive according to the present invention includes a boss 28a extended at a predetermined height at an arbitrary point on the mechanism base 10 and a boss 28b located on the outer peripheral surface of the boss 28a, Shaped elastic member 34 positioned on both sides of the elastic body 34 in the direction perpendicular to the feeding direction of the optical pickup and in the direction of feeding movement of the optical pickup and the elastic body 34 located on the outer peripheral surface of the elastic body 34, And a mass compensating body (32).

The elastic body 34 is positioned so as to face the outer peripheral surface of the boss 28a in the tracking direction and is supported by the elastic body 34 and the lower end surface of the mass correction body 32 28b. The screw 28 is fitted through the inner diameter of the vertical fixing piece 28b and the inner diameter of the boss 26a to fix the elastic body 34 and the mass correction body 32 and the vertical fixing piece 28b. Then, the mass correction body 22 is fixed in the vertical direction of the mechanism base 10, and the vibration of the mass correction body 22 is controlled by the elastic body 22 in the tracking direction. When the rotation frequency of the disk, the elastic modulus of the elastic material, and the mass of the mass corrector are set to appropriate values, vibration in the tracking direction can be suppressed regardless of the rotational frequency of the disk. The configuration of the mass correction body 22 and the elastic body 24 disposed opposite to the tracking direction as described above is such that when the objective lens vibrates as the mechanism base 10 vibrates in the horizontal direction, It can be usefully applied for the purpose of effectively suppressing vibration.

As described above, the vibration absorbing device of the disk driver of the present invention has an advantage in that vibration and noise can be suppressed by making the center of gravity coincide with the center of rotation.

The vibration absorber of the disk drive of the present invention has an advantage that the center of gravity is coincident with the center of rotation and the vibration of the optical pickup is suppressed, thereby enabling accurate recording / reproduction.

It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit or scope of the invention. Therefore, the technical scope of the present invention should not be limited to the contents described in the detailed description of the specification, but should be defined by the claims.

Claims (5)

A recording / reproducing apparatus comprising: a spindle motor for rotating a disc; and an optical pickup for irradiating a light beam onto an information recording surface of the disc and converting a light beam reflected from the information recording surface of the disc into an electrical signal, A mechanism base on which the spindle motor and the optical pickup are mounted, And at least one mass compensating means located at one side of the mechanism base and suppressing vibration of the mechanism base regardless of the rotational speed of the disk at a mass m2. The method according to claim 1, Wherein the mass correction means comprises elastic means fixed to one side of the mechanism base with an elastic modulus, And a mass body fixed to one side of the elastic means. The method according to claim 1, Wherein the mass correction means satisfies a relationship of ω ² = k ² / m ² (ω is rotational speed of disk, k 2 is a spring constant of the mass correction means, and m 2 is mass of the mass correction means) And the vibration is absorbed by the disk. The method according to claim 1, Wherein the mass correction means comprises a cylindrical first mass located at one side of the mechanism base to suppress vibration of the mechanism base relative to all radial directions of the disk, And a first elastic body fitted to the inner diameter of the first mass body. The method according to claim 1, The mass correction means includes a second mass located at one side of the mechanism base to suppress the vibration of the mechanism base with respect to the transport direction of the optical pickup, And a second elastic body which is fitted in the inner diameter of the second mass body and is positioned so as to face the transport direction of the optical pickup.