KR20120048323A - Disk drive - Google Patents

Abstract

PURPOSE: A disk drive is provided to reduce a movement noise due to an optical recording medium, noises of a loading system and a feeding system, and a noise due to rotation of a motor. CONSTITUTION: A tray(120) slides on a main frame(110). A cover(140) is combined with the main frame. At least one bead(142,143) is formed on the cover. Beads are formed at a fixed interval in a noise reducing unit(150). The decreasing noise unit flows airflow due to the rotation of disc to the space part. The noise reducing unit reduces a noise of a specific frequency band by the Helmholtz resonance principle.

Description

Disk Drive {Disk Drive}

The present invention relates to a disk drive, and more particularly, to a disk drive having a noise reduction unit capable of removing noise of a specific frequency by using Helmholtz resonance for air flow generated when the disk is rotated.

A disc drive refers to a device for recording or reading information by irradiating light onto an optical recording medium such as a compact disc (CD) or a digital video disc (DVD).

The basic configuration of the disc drive includes a spindle motor for rotating the disc, a loading device for transporting and mounting the disc to the spindle motor, an optical pickup unit for reproducing or recording information of the disc, and a step for reciprocating the optical pickup unit in and around the disc. It consists of a motor and a main chassis for mounting the optical pickup unit, spindle motor and step motor. It also includes a cover for forming the exterior and protecting the internal structure and the electronic device.

The overall size of the cover is regulated and cannot be arbitrarily changed, but the beads on the top of the cover have been designed with various shapes and depths. The main purpose of the beads has been to focus on the role of minimizing the vibration of the cover when it is transmitted to the cover along the inner structure by increasing the rigidity of the cover and the vibration generated by the rotation of the disk. As a result, the present inventors are trying to design a bead shape to generate the sag and noise reduction effect of the disk by controlling the flow flow in the disk drive as well as increasing the rigidity.

In particular, the structure is designed to act as an air bearing to attenuate the vibration of the disk by applying the flow of air generated by the rotation of the disk to the surface of the optical disk by applying the flow of air generated by the rotation of the disk to the surface of the disk It was also made. The beads of the cover have been designed in shape and depth in consideration of the flow of the disk and the rigidity of the cover.

Air flow due to the rotation of the disk, the operation of the feeding system, the operation of the loading system, and the like provide a cause of noise. Among them, aerodynamic noise by air flow makes up most of the noise sources. The noise is propagated by the vibration of the air particles and has the characteristic of radiating in all directions. When the acoustic energy is analyzed electronically by the frequency bands in which the effective pressure is connected, it can be seen that the band of about 1000 to 4000 Hz is the main frequency component that constitutes aerodynamic noise.

In order to reduce the noise of this frequency band, there is a method of reducing the noise by adjusting the thickness of the cover or maximizing the transmission loss caused by the acoustic energy passing through the cover using a sound absorbing material and a sound insulating material. Changes in weight and shape are not efficient.

Due to these limitations, in the case of a disk drive, a method of reducing the noise caused by the disk shaking is applied by applying a flow of air to the surface of the disk by changing the shape of the bead. However, since the noise is reduced through the micro pressure distribution, the noise reduction effect is insignificant. In addition, the bead serves to reduce the vibration caused by the flow of the spindle motor, the stepper motor and the disc by providing the rigidity to the cover, but the noise reduction role of the bead is limited in view of the fact that the noise of the disc drive is mostly caused by the flow of the disc. to be.

The present invention provides a disk drive having a noise reduction unit that can reduce the noise generated when the disk flows by utilizing the space formed in the cover by the bead for the Helmholtz resonance principle.

Disc drive according to an aspect of the present invention,

Mainframe,

Slidably installed on the mainframe, the tray on which the disk is seated,

A cover coupled to the mainframe, the cover having at least one bead formed so as to be recessed from an upper side thereof;

A bead is formed in a predetermined space portion, and a noise reduction unit is provided so that air flow generated when the disk is rotated flows into the space portion to reduce noise in a specific frequency band by using the Helmholtz resonance principle.

The noise reduction unit includes a plurality of holes formed to penetrate the beads,

A lid is formed to cover the upper surface of the bead and form a space therein.

The plurality of holes are circular and are arranged at equal intervals from each other.

The beads are arranged symmetrically with the clamper installed in the cover therebetween.

The cover is made of the same material as the material constituting the cover.

By adjusting the diameter of the hole and the distance between the holes, the desired target frequency can be selected.

The target frequency is 1500Hz to 3000Hz.

Disc drive according to the present invention

First, through the simple process of forming the hole and attaching the cover, it is possible to reduce the flow noise and the loading system by the optical recording medium, the noise by the operation of the feeding system, and the noises by the rotation of the motor. In particular, by applying the present invention on the top of the cover with a large amount of noise radiation, the overall noise reduction effect is large.

Second, by maintaining the shape of the existing clapper and bead is possible to drive a stable disk, vibration and flow noise due to flutter by the flow can also be reduced.

Third, the noise reduction unit is easy to apply and use the technology by applying to the bead freely change the shape.

1 is an exploded perspective view showing a disk drive having a noise reduction unit according to the present invention.
Figure 2 is a perspective view of the cover shown in FIG.
3 is a cross-sectional view taken along line AA ′ of FIG. 1;
Figure 4 is a view for explaining the Helmholtz resonance principle.
5 is a graph comparing the noise reduction effect of the noise reduction unit when the target reduction frequency according to the present invention is set to 2500 Hz.
<Description of the symbols for the main parts of the drawings>
100 --- disk drive 110 --- mainframe
111 --- Subframe 112 --- Base Chassis
113 --- Turntable 114 --- Optical Pick-Up Unit
120 --- tray 121 --- mounting
140 --- cover 141 --- clamper
142,143 --- Bead 150-Noise reduction unit
151,152 --- Cover 153 --- Space
154 --- hole

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. However, the embodiments illustrated below are not intended to limit the scope of the invention, but rather to provide a thorough understanding of the invention to those skilled in the art. In the drawings, like reference numerals refer to like elements, and the size of each element in the drawings may be exaggerated for clarity and convenience of description.

1 is an exploded perspective view showing a disk drive having a noise reduction unit according to the present invention, Figure 2 is a perspective view of the cover shown in Figure 1, Figure 3 is a cross-sectional view taken along line AA 'of Figure 1 to be.

Referring to FIGS. 1 and 2, the disc drive 100 includes a main frame 110 and a tray provided with a mounting unit 121 installed on the main frame 110 so that the optical recording medium D is mounted thereon. 120, a subframe 111 rotatably installed on the main frame 110, and a base chassis 112 installed to be supported by the subframe 111.

The main frame 110 is provided with a sliding member 118 which is installed to slide in cooperation with the drive motor 115 in a direction perpendicular to the direction in which the tray 120 enters and exits. A plurality of cam holes (not shown) are formed in the sliding member 118, and the cam protrusion 119 provided in the subframe 111 slides along the trajectory of the cam hole (not shown), and as a result, the subframe 111 ) Is rotated up and down about the pivot shaft 111a supported by the main frame 110.

The base chassis 112 has a turntable 113 on which the optical recording medium D mounted and transported in the tray 120 is mounted, and is coaxial with the turntable 113 to rotate the turntable 113. An optical pickup unit 114 for recording information on the optical recording medium D or reproducing the recorded information while sliding in a radial direction of the spindle motor (not shown) and the optical recording medium D seated on the turntable 113. This is installed.

The front of the tray 120 is provided with a switch 130 for outputting a signal for loading or unloading the tray 120 to the main frame 110.

The upper surface of the main frame 110 is covered by the cover 140. The cover 140 is provided with a clamper 141 for clamping the optical recording medium D mounted on the turntable 113.

Two beads 142 and 143 are formed on both sides with a clamper 141 interposed therebetween so as to dent a predetermined depth. Beads 142 and 143 are formed to increase the rigidity of the cover 140, and the shape and position of the beads 142 and 143 are determined in consideration of the rigidity, and are not limited to those shown in the drawings of the present invention.

The beads 142 and 143 are provided with a noise reduction unit 150 for removing noise of a specific frequency band generated when the optical recording medium D is rotated using the Helmholtz resonance principle.

The noise reduction unit 150 includes covers 151 and 152 covering the upper sides of the beads 142 and 143, and a lower side (142 a in FIG. 3) (143 a in FIG. 3) of the beads 142 and 143. It is provided with a plurality of holes 154 formed to penetrate.

The portion occupied by the beads 142 and 143 occupies the space portion 153 by the lid 151 and 152. That is, the beads 142 and 143 are separated from the outside by the covers 151 and 152 and the space portion 153 is formed as much as the depressions. The cross sections of the plurality of holes 154 are circular and are arranged at equal intervals from each other. The covers 151 and 152 may be formed of a metal or plastic material, and may be formed of the same material as the cover 140.

Referring to FIG. 3, sound waves (arrows indicated by solid lines) of a specific noise frequency of 1000 to 4000 Hz, which are generated while the optical recording medium (D of FIG. 1) is rotated, are transferred to the space portion 153 through the plurality of holes 154. When introduced, the sound waves of a specific frequency set according to the size of the hole 154 and the distance between the hole 154 and the cover 151 and 152 cause a resonance action, and thus the air in the hole 154 portion is severely moved. The energy of sound waves is converted into thermal energy (arrows indicated by solid lines) by friction loss, and sound absorption is performed.

4 is a view for explaining the Helmholtz resonance principle.

Referring to FIG. 4, the upper member 210 and the lower member 220 are spaced apart by a distance d, and a plurality of holes 230 are formed through the upper member 210. The holes 230 are arranged at equal intervals by each other B, the radius of the hole 230 is a, and when the thickness of the upper member 210 is h, the Helmholtz equation is as follows.

Where f is frequency and C is sound velocity.

In contrast to the above configuration, the upper member 210 corresponds to the bead 142, the lower member 220 corresponds to the cover 151, the hole corresponds to the hole 154.

In general, the noise of the disk drive is mainly generated with a noise having a fundamental frequency of 1000 ~ 4000Hz, and the noise corresponding to the frequency of multiples thereof. Normally, the noise is evaluated as a transmission loss, and the noise is reduced by increasing the transmission loss on the noise frequency band. Therefore, the Helmholtz resonator is applied in the region where the transmission noise is low to increase the transmission loss at the specific frequency.

In the present invention, by reducing the resonant frequency of the Helmholtz resonator to a specific frequency in order to increase the transmission loss of the target frequency can reduce the noise of the corresponding frequency band.

For example, when the noise reduction target frequencies are set to 1600 Hz and 2500 Hz, assuming that d, h, and C are fixed, the noise of the target frequency can be reduced by changing a and B.

F (Hz) d (cm) h (cm) a (cm) B (cm) C (cm / s) 1600 0.3 0.06 0.1 2.333361779 34000 1600 0.3 0.06 0.15 2.997257474 34000 1600 0.3 0.06 0.25 4.03417295 34000

F (Hz) d (cm) h (cm a (cm) B (cm) C (cm / s) 2500 0.3 0.06 0.1 1.493351539 34000 2500 0.3 0.06 0.15 1.9118244784 34000 2500 0.3 0.06 0.25 2.581870688 34000

Referring to Table 1, it can be seen that when the target frequency is set to 1600 Hz, the desired target frequency (1600 Hz) can be set by changing the radius (a) of the hole and the distance (B) between the holes. In addition, it can be seen from Table 2 that when the target frequency is 2500 Hz, the desired target frequency (2500 Hz) can be set by changing the radius (a) of the hole and the distance (B) between the holes.

5 is a graph comparing the noise reduction effect of the noise reduction unit when the target reduction frequency according to the present invention is set to 2500 Hz.

5, the horizontal axis represents frequency and the vertical axis represents decibels of noise. As a result of applying the noise reduction unit according to the present invention, it can be seen that the noise is generally reduced, and in particular, it can be seen that the noise reduction effect is large in the flow noise band centered on 2500 Hz.

Therefore, in order to reduce noise in the 1500 Hz to 3000 Hz flow noise band, it is possible to calculate the frequency of the desired flow noise band through the shape change to change the radius of the hole and the distance between the holes.

The above-described disk drive of the present invention has been described with reference to the embodiments shown in the drawings for clarity, but this is merely exemplary, and various modifications and equivalent other embodiments are possible to those skilled in the art. Will understand. Therefore, the true technical protection scope of the present invention will be defined by the appended claims.

Claims (7)

Mainframe;
A tray slidably installed on the main frame and on which a disk is seated;
A cover coupled to the main frame, the cover having at least one bead formed to be recessed from an upper side thereof; and
And a noise reduction unit which forms the beads in a predetermined space portion and reduces the noise of a specific frequency band by using Helmholtz resonance principle by allowing air flow generated during the rotation of the disk to flow into the space portion. The method of claim 1,
The noise reduction unit
A plurality of holes formed to penetrate the beads;
And a cover covering an upper surface of the bead to form a space therein. The method of claim 2,
The plurality of holes are circular, and are arranged at equal intervals from each other. The method of claim 3, wherein
And the beads are symmetrically arranged with the clamper installed in the cover therebetween. The method of claim 2,
The cover is a disk drive made of the same material as the material constituting the cover. The method of claim 2,
And a desired target frequency can be selected by adjusting the diameter of the hole and the distance between the holes. The method of claim 6,
The target frequency is set to 1500Hz ~ 3000Hz disk drive that can reduce the overall aerodynamic noise band.

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