JP4082363B2 - Disk drive - Google Patents

Description

  The present invention relates to a disk drive device that rotates an optical disk.

  2. Description of the Related Art Conventionally, information recording / reproducing apparatuses that record or reproduce information by driving an optical disc are widely known. Such an information recording / reproducing apparatus is provided with a disk drive device that rotates an optical disc and irradiates a pit formed on the optical disc with a laser beam of an optical pickup to read the pit. An optical disk is clamped on a turntable, and the turntable may generate vibrations due to vibrations generated from a drive source such as a spindle motor or the rotational motion itself. This vibration causes a decrease in the reading accuracy of the pits, which in turn causes deterioration in recording and reproduction characteristics.

  In addition, since the turntable is driven to rotate at a high speed, unnecessary sounds such as wind noise may be generated. This sound made the user feel uncomfortable and uncomfortable and was undesirable. In particular, the generation of unnecessary sounds has been a problem in a reproducing apparatus that also reproduces sound information such as music and video.

  Therefore, many techniques for reducing vibration have been proposed. For example, Patent Document 1 discloses a disk device including a turntable on which a permanent magnet is fixed and a suction yoke provided in the vicinity of the permanent magnet. According to this, since the restraint force is generated on the turntable by the suction yoke, the vibration resistance is improved.

  As a simpler method, a disk device in which a plate made of brass or the like is attached to a turntable is also known. According to this, the plate works as a damping member, and the vibration resistance of the turntable is improved.

JP 2003-339143 A

  However, since the structure of the disk device of Patent Document 1 is relatively complicated, a simpler method is desired. The method of attaching the plate can be easily realized, but cannot be applied to a disk drive device such as DVD or SACD that requires high-speed rotation because the moment of inertia increases.

  Moreover, unnecessary sounds such as wind noises were generated by the rotational drive of the turntable, causing discomfort and discomfort for the user, but such unnecessary sounds could not be reduced by the above-described technology. .

  Accordingly, an object of the present invention is to provide a disk drive device that reduces noise generated by rotational driving and further reduces vibrations generated in a turntable.

The disk drive device of the present invention is a turntable for rotationally driving an optical disk, a turntable having substantially the same diameter as the optical disk, and a fixed disk disposed opposite to the turntable via an air layer , have a, a fixed disk having a size to cover at least the entire surface of the turntable, the thickness of the air layer, or surface deflection amount of the turntable generated by the rotation, and is 2mm or less, and wherein the .

In a preferred embodiment, the thickness of the air layer is approximately 0.5 mm. In another preferred embodiment, the fixed disk is sized to cover at least substantially the entire surface of the turntable . In another preferred embodiment, the fixed disk has one or more ribs on the surface facing the turntable for increasing the air resistance when the turntable rotates .

  Here, the optical disc refers to all media that read and record information with light, such as a compact disc (CD), a digital video disc (DVD), and a super audio CD (SACD).

  According to the present invention, since the sound generated from the turntable is absorbed by the fixed disks arranged in proximity, the sound generated at the time of rotational driving can be reduced. In addition, since the air layer formed between the turntable and the fixed disk functions as an air damper, vibration generated when the turntable is driven to rotate can be reduced.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 shows a cross-sectional view of a main part of a disk drive device 10 according to an embodiment of the present invention.

  The disk drive device 10 includes a transport mechanism 14 that transports an optical disk 36, a clamp mechanism 16 that clamps the optical disk to a turntable 30, an optical pickup mechanism 18 that irradiates the optical disk 36 with laser light and reads pits, and an optical disk 36. It has the drive part 12 which rotationally drives.

  The transport mechanism 14 has a transport tray 40 that can move between the inside and the outside of a housing (not shown), and the optical disk 36 is appropriately placed outside the housing or below the turntable 30. Transport. The clamp mechanism 16 clamps the optical disk 36 on the turntable 30 and has a clamp member 44 that can move up and down. When the optical disk 36 is conveyed below the turntable 30, the clamp member 44 pushes up the optical disk 36 by moving upward and clamps it on the turntable 30. The optical pickup mechanism 18 is movably disposed below the turntable 30, that is, below the clamped optical disk 36. The optical pickup mechanism 18 reads pit information by irradiating the pits of the optical disk 36 with laser light.

  Next, the drive unit 12 will be described with reference to FIG. FIG. 2 is a schematic sectional view of the drive unit 12. The drive unit 12 includes a base 20 that supports the entire drive unit 12, a turntable 30 that rotationally drives the optical disk 36, and a fixed disk 32 that is disposed in proximity to the turntable 30.

  The turntable 30 is a disk-shaped member having substantially the same diameter as the optical disk 36 and holds the optical disk 36 on the lower surface thereof. The turntable 30 is attached to the rotating shaft 26 and is driven to rotate together with the rotating shaft 26 by the spindle motor 24. The rotating shaft 26 is attached to the base body 20 via a bearing 22. The base 20 supports the entire drive unit 12 and is attached to a housing (not shown).

  A fixed disk 32 is provided above the turntable 30. The fixed disk 32 is a disk-shaped member made of a lightweight material such as acrylic, and is a fixed member attached to the base body 20. The fixed disk 32 has the same diameter as the turntable 30 and has a size that covers the entire surface of the turntable 30. Then, it is disposed in close proximity to the upper surface of the turntable 30, that is, the surface opposite to the surface that holds the optical disk 36, and a thin air layer 34 is formed between the upper surface of the turntable 30.

  As will be described later, since this fixed disk 32 functions as a sound absorbing member and an air damper forming member, it is desirable that the fixed disk 32 be disposed close to the turntable 30. However, when the turntable 30 is rotationally driven, a slight surface vibration occurs. Therefore, in order to prevent contact between the fixed disk 32 and the turntable 30, it is desirable that the thickness of the air layer 34 is at least larger than the amount of surface deflection. In general, the surface runout caused by the rotational drive of the turntable 30 is about 0.3 mm. Therefore, in the present embodiment, the thickness of the air layer 34, that is, the distance between the upper surface of the turntable 30 and the lower surface of the fixed disk 32 is , 0.5 mm. However, it is not limited to this numerical value, and may be another value. In that case, it is suitable that it is 2 mm or less. Among these, it is desirable that it is 1 mm or less, and it is still desirable if it is 0.5 mm or less.

  By providing the fixed disk 32 through such a thin air layer 34, it is possible to reduce sound and vibration generated when the turntable 30 is driven to rotate.

  That is, when the turntable 30 is rotationally driven, the turntable 30 is likely to vibrate due to vibrations generated from the spindle motor 24 and the rotational motion itself. This vibration lowers the accuracy of the optical pickup, which in turn leads to deterioration of information recording and reproduction characteristics. However, by forming the thin air layer 34 above the turntable 30 as in the present embodiment, the air layer 34 functions as a damper and restrains the turntable 30.

  Further, by providing the fixed disk 32 in the vicinity, unnecessary sound such as wind noise generated by the rotation drive of the turntable 30 is absorbed by the fixed disk 32 without leaking outside. Thereby, generation | occurrence | production of the unnecessary sound at the time of the rotational drive of the optical disk 36 can be reduced.

  An experiment for examining the relationship between the silencing effect and the thickness of the air layer will be described with reference to FIGS. FIG. 3 is a diagram showing the experimental conditions. In the experiment, an M3 × 8 cap screw 52 is dropped onto the turntable 30 from a height of 80 mm, and the sound pressure generated at that time is measured by the sound level meter 50. The distance between the turntable 30 and the sound level meter 50 is 20 cm. The distance between the turntable 30 and the fixed disk 32, that is, the air layer thickness t, which is the thickness of the air layer 34, is six types of 3.5 mm, 2 mm, 1 mm, 0.9 mm, 0.5 mm, and 0.2 mm. The measurement is performed 6 times for each air layer thickness t, and the average value is used as the experimental result. The environment in which the experiment was performed is a background noise level of 35 dB.

  FIG. 4 is a graph showing the results of this experiment, where the horizontal axis represents the air layer thickness t and the vertical axis represents the sound pressure. Note that the sound pressure on the vertical axis is the sound pressure actually measured by the sound level meter, and is a value to which background noise of 35 dB is also applied. However, this background noise 35 db is negligible because it is about 1 / 100th the magnitude of the measured value (74 dB to 81 dB).

  As apparent from FIG. 4, the measured sound pressure hardly changes when the air layer thickness t is between 3.5 mm and 2.0 mm. When the air layer thickness t becomes smaller than 2.0 mm, the sound pressure tends to gradually decrease. Then, when the air layer thickness t exceeds 1 mm, the tendency rapidly decreases and becomes almost constant at 0.5 mm or less.

  The sound pressure generated by dropping is about 80 dB when the air layer thickness t = 3.5 mm, and about 75 when the air layer thickness t = 0.5 mm. Therefore, by setting the air layer thickness t = 0.5 mm, the sound pressure generated by dropping is reduced by about 5 dB (about 45% reduction) compared to the case where the air layer thickness t = 3.5 mm.

  As is clear from this experiment, by providing the fixed disk 32 arranged oppositely in the vicinity of the turntable 30, unnecessary sounds such as wind noise and the like, and further vibrations of the turntable 30 are reduced. be able to.

  As described above, according to the present embodiment, unnecessary sounds such as wind noise generated during rotation driving can be reduced. Moreover, the vibration which arises in the turntable 30 at the time of rotational drive can be reduced.

  In the present embodiment, the material of the fixed disk 32 is a lightweight material such as acrylic. However, the material is not limited to this, and other metal materials or resins may be used. In addition, the fixed disk 32 has substantially the same diameter as the turntable 30, but may be equal to or larger than the turntable 30.

  Further, as shown in FIG. 5, the fixed disk 32 may be provided with a side wall 32 a that covers the side surface of the turntable 30. The side surface (outer periphery) of the turntable 30 has the fastest peripheral speed and is likely to generate wind noise. By providing the side wall 32a covering the side surface of the turntable 30, sound leaking from the side surface of the turntable 30 can be more reliably absorbed and noise such as wind noise can be further reduced. In addition, an air damper is also formed on the side surface of the turntable 30, and vibration generated in the turntable 30 can be further reduced.

  Furthermore, one or more ribs may be provided on the lower surface of the fixed disk 32, that is, on the surface facing the turntable 30. By providing the rib, the air resistance during rotation of the turntable 30 increases, and the force for restraining the turntable 30 increases. Therefore, vibration generated in the turntable 30 can be further reduced. A plurality of ribs are desirable, and it is particularly desirable that the ribs are provided radially around the center point of the fixed disk.

1 is a schematic sectional view of a disk drive device according to an embodiment of the present invention. It is principal part sectional drawing of a disk drive device. It is a figure which shows the experimental condition of the experiment which investigates the relationship between air layer thickness and a silencing effect. It is a graph which shows the experimental result of the experiment shown in FIG. It is a schematic sectional drawing of another disk drive device.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 Disk drive device, 12 Drive part, 14 Conveyance mechanism, 16 Clamp mechanism, 18 Optical pick-up mechanism, 20 Base, 24 Spindle motor, 26 Rotating shaft, 30 Turntable, 32 Fixed disk, 34 Air layer, 36 Optical disk, 50 Noise Total.

Claims (4)

A disk drive device,
A turntable for rotating and driving an optical disc, the turntable having substantially the same diameter as the optical disc;
A fixed disk disposed opposite to the turntable via an air layer, the fixed disk having a size covering at least the entire surface of the turntable ;
I have a,
The thickness of the air layer is not less than the amount of runout of the turntable caused by rotation and not more than 2 mm.
A disk drive device characterized by that. The disk drive device according to claim 1,
A disk drive device characterized in that the thickness of the air layer is approximately 0.5 mm. The disk drive device according to claim 1 or 2 ,
The disk drive device, wherein the fixed disk has a side wall that covers a side surface of the turntable. The disk drive device according to any one of claims 1 to 3 ,
The fixed disk has one or more ribs for increasing air resistance during rotation of the turntable on a surface facing the turntable .

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