JP2008002519A - Automatic balancing device, rotating device and disk drive device - Google Patents

Abstract

To provide an automatic balancing device capable of reliably balancing, a rotating device and a disk drive device equipped with the same.
An automatic balancing apparatus includes a case in which a plurality of magnets functioning as a balancer are housed. The case 2 has an opening in the upper part, and the cover 1 is attached to the opening to constitute the housing 5. Since the magnet 11 as a balancer has a high specific gravity like a conventional metal ball or the like, a balance can be reliably obtained. Moreover, since the magnetic fluid 9 adheres to the magnet 11 and the magnet 11 moves smoothly, noise due to the movement of the conventional metal sphere can be reduced. The moving road surface 2 d of the moving space 14 of the magnet 11 is provided so as to incline downward from the outer peripheral side of the housing 5 toward the inner peripheral side. Thereby, after completion | finish of operation | movement of the automatic balancing apparatus 10, a magnetic fluid can be rapidly returned to an inner peripheral side by the dead weight of a magnetic fluid.
[Selection] Figure 3

Description

  The present invention relates to an automatic balancing device for maintaining a balance of rotation, a rotating device equipped with the device, and a disk drive device.

  For example, in a disk device such as an optical disk device or a magnetic disk device that records / reproduces data, when the disk as a recording medium rotates on a turntable, the rotation becomes unbalanced due to the eccentricity of the disk, and recording / reproduction is performed. The stability of the may decrease.

  As a technique for improving the balance of disk rotation, a technique for causing a fluid to function as a balancer is disclosed (for example, see Patent Documents 1 and 2). In Patent Document 1, the fluid is a magnetic fluid, and a disk-shaped member having a space that can accommodate the fluid is provided so as to be rotatable integrally with the motor shaft. The disk-shaped member has a boss portion, and a ring magnet is attached to the side peripheral surface of the boss portion. Thereby, when the rotation speed of a rotating shaft is small, a magnetic fluid is attracted | sucked to a ring magnet so that balance may not be lost.

  Further, in Patent Document 2, when the automatic balancing apparatus is not in operation, the fluid balancer is held with surface tension by a holding member provided on the inner peripheral side of the housing member.

JP-A-4-31244 (paragraph [0006], FIG. 1) Japanese Patent Laying-Open No. 2005-331102 (paragraph [0037], FIG. 2)

  However, since a fluid balancer is lighter than a conventional balancer made of a metal sphere or the like, noise is ensured, but there is a problem that it is difficult to balance.

  In view of the circumstances as described above, an object of the present invention is to provide an automatic balancing device that can be surely balanced, a rotating device equipped with the same, and a disk drive device.

  Another object of the present invention is to provide a technique capable of quickly returning the magnetic fluid to the inner peripheral side at the end of the operation of the automatic balancing apparatus.

  In order to achieve the above object, an automatic balancing apparatus according to the present invention has a plurality of magnets functioning as a balancer, a magnetic fluid, a moving path surface on which the magnet and the magnetic fluid move, and is rotatably provided. A housing for housing the magnet and the magnetic fluid, the moving road surface being provided so as to incline downward from the outer peripheral side to the inner peripheral side of the rotation.

  In the present invention, since the specific gravity of the magnet is high like a conventional metal sphere or the like, a balance can be reliably obtained. In addition, since the magnetic fluid adheres to the magnet functioning as a balancer and the magnet moves smoothly, noise due to the movement of the conventional metal sphere can be reduced.

  Further, since the moving road surface is inclined downward from the outer peripheral side to the inner peripheral side of the rotation of the housing, the weight of the magnetic fluid is reduced after the balance is achieved and when the rotation of the housing is decelerated or after the operation is completed. Thus, the magnetic fluid can be quickly returned to the inner peripheral side.

  In the present invention, the housing has a ceiling surface provided so as to face the moving road surface and to be inclined downward from the outer peripheral side toward the inner peripheral side.

  In the present invention, each of the magnets is formed in a circular arc block shape, the housing has a horizontal ceiling surface facing the moving road surface, and the moving road surface is in an attitude of each magnet with respect to the ceiling surface. Is provided at an angle such that the angle is maintained. When the moving road surface is inclined and the ceiling surface is horizontal, the distance between the moving road surface and the ceiling surface on the inner peripheral side increases as the inclination of the moving road surface from the horizontal plane increases. Therefore, the posture may change depending on the size of the magnet as the inclination of the moving road surface increases. In that case, the magnets arranged in such a posture that the magnets repel each other will be attracted to each other by changing the posture. In the present invention, the moving road surface is provided with an inclination of an angle to prevent such a situation.

  The rotating device according to the present invention includes a plurality of magnets functioning as a balancer, a magnetic fluid, a moving path surface on which the magnet and the magnetic fluid move, and is rotatably provided. The moving path surface is an outer periphery of the rotation. A housing for accommodating the magnet and the magnetic fluid, which is provided so as to be inclined downward from the side toward the inner peripheral side, and a rotation mechanism for rotating the housing.

  A disk drive device according to the present invention includes a holding unit for holding a disk-shaped recording medium capable of recording a signal, a plurality of magnets functioning as a balancer, a magnetic fluid, and a moving path surface on which the magnet and the magnetic fluid move. A housing that accommodates the magnet and the magnetic fluid, and is provided so as to be rotatable, and the moving road surface is inclined downward from the outer peripheral side to the inner peripheral side of the rotation, and the holding portion And a drive mechanism for integrally rotating the housing.

  As described above, according to the present invention, it is possible to surely achieve a balance and improve the quietness. Further, the magnetic fluid can be quickly returned to the inner peripheral side at the end of the operation of the automatic balancing apparatus.

  Embodiments of the present invention will be described below with reference to the drawings.

  FIG. 1 is an exploded perspective view showing an automatic balancing apparatus according to an embodiment of the present invention. 2 is a cross-sectional view of the automatic balancing apparatus shown in FIG. 1, and FIG. 3 is a cross-sectional view taken along line AA in FIG. The automatic balancing apparatus 10 includes a case 2 that houses therein a plurality of magnets 11 that function as balancers. The case 2 has an opening in the upper part, and the cover 1 is attached to the opening to constitute the housing 5. A cylindrical boss 2b protruding upward is formed in the center of the inside of the housing 5. A moving space 14 in which the magnet 11 moves is formed between the outer peripheral wall surface 2a in the housing 5 and the side surface 2f of the boss portion 2b. The upper and lower spaces of the moving space 14 are limited by the moving road surface 2d and the ceiling surface 1b (the back surface of the cover 1) facing the moving road surface 2d.

  A flange 2c is provided on the upper surface of the boss portion 2b, and a hole 1a (see FIG. 1) formed substantially at the center of the cover 1 is fitted in the flange 2c. The cover 1 and the case 2 are bonded by, for example, welding, pressure bonding, laser bonding, or the like, but are not limited to these bonding methods. The constituent material of the cover 1 and the case 2 is made of a material that is not affected by the magnetism of the magnet 11 described later. Examples of the material include plastics such as polycarbonate, aluminum alloys, bronze alloys, and ceramics.

  As shown in FIG.2 and FIG.3, the rotating shaft member 16 is inserted and fixed to the through-hole 2e formed in the boss | hub part 2b. As will be described later, the rotating shaft member 16 is a rotating shaft member of a motor provided in, for example, a device on which the automatic balancing apparatus 10 is mounted, or a coaxial shaft member that is separate from the rotating shaft member. The magnet 11 has an arc block shape forming a part of the ring. For example, four magnets 11 are provided, but any number of two or more magnets 11 may be used as long as they function as a balancer. As shown in FIG. 3, these magnets 11 are magnetized, for example, substantially in the direction of the rotation axis (Z direction) of the housing 5, and are magnetized so that the same poles face the same side. Thereby, when the magnets 11 approach each other, they repel each other. For example, ferrite or neodymium is used as the magnet 11, but is not limited thereto.

  A magnetic fluid 9 is attracted and held around the magnet 11 by the magnetic force of the magnet 11. Instead of the magnetic fluid 9, a magnetoresistive fluid (MR fluid (Magneto-Rheological Fluid)) or the like may be used. As a solvent for the magnetic fluid 9, water, oil, sodium polytungstate, or the like is used, but is not limited thereto. When the magnetic fluid 9 clings to the magnet 11, the magnet 11 floats in the moving space 14 during non-operation as shown in FIGS. 2 and 3. The magnetic fluid 9 needs to have such an amount that the magnet 11 can float as shown in FIG.

  The moving road surface 2 d of the moving space 14 is provided so as to be inclined downward from the outer peripheral side of the housing 5 toward the inner peripheral side. Thereby, as will be described later, the magnetic fluid can be quickly returned to the inner peripheral side by the dead weight of the magnetic fluid after the operation of the automatic balancing apparatus 10 is completed. The inclination angle of the moving road surface 2d with respect to the horizontal plane is, for example, 3 to 10 degrees. However, it is not limited to this, and can be set as appropriate.

  In addition, the inclination angle needs to be provided at an angle such that the posture of each magnet 11 is maintained with respect to the ceiling surface 1b provided horizontally. The reason is as follows. In the case of the housing 5 according to the present embodiment, the greater the inclination of the moving road surface 2d from the horizontal plane, the greater the distance between the moving road surface 2d and the ceiling surface 1b on the inner peripheral side. That is, the posture may change depending on the size of the magnet 11 as the inclination of the moving road surface 2d increases. In that case, the magnets arranged in such a posture that the magnets 11 repel each other are attracted to each other when the posture is changed.

  Further, a> b is set, where a is the radial width of the magnet 11 and b is the distance from the moving road surface 2d to the ceiling surface 1b in the innermost circumference of the moving space 14. According to such a configuration, it is possible to prevent the magnet 11 from moving in the moving space 14 and upside down and reversing the magnetization direction of the magnet 11.

  FIG. 4 is a cross-sectional view showing a disk drive device on which the automatic balancing apparatus 10 is mounted.

  The disk drive device 100 includes a motor 61, and a turntable 65 that holds the disk D is provided at the upper end of the rotating shaft member 16 of the motor 61. The motor 61 includes, for example, a stator 61b provided with a coil 61d through which a drive current flows, a rotor 61c provided with a magnet 61e and rotatably provided via a bearing 61a, and the rotating shaft member 16. As described above, the automatic balancing device 10 is mounted on the rotating shaft member 16, and the automatic balancing device 10 is configured to be rotatable integrally with the rotating shaft 16. The motor 61 is supported by a sub-chassis 63, and the sub-chassis 63 is supported by a main chassis 64 via an elastic body 62 made of a polymer material such as rubber, a metal member, and the like, thereby constituting a vibration system. That is, the vibration system here is the vibration of all members above the main chassis 64 with respect to the main chassis 64. For example, the resonance frequency of the vibration system due to the deformation of the elastic body 62 is set to be smaller than the rotation frequency of the disk D.

  The disc is, for example, a CD (Compact Disc), a DVD (Digital Versatile Disc), a BD (Blu-ray Disc (registered trademark)), or an optical disc capable of recording or reproducing a signal by an optical method such as a hologram. And magneto-optical disks such as MO (Magneto Optical disk) and MD (Mini-Disk), magnetic disks such as hard disks, and the like.

  Next, the operation of the automatic balancing apparatus 10 will be described. 5 and 6 are diagrams showing the operation in order.

  When the disk D is set on the turntable 65 and the motor 61 starts to rotate, the vibration system starts to vibrate. As shown in FIG. 5A, for example, it is assumed that an unbalance 15 exists in the disk D and the disk D is eccentric. Note that the cause of the imbalance 15 is not limited to the disk D, and may exist in other parts of the disk drive device 100. At the initial rotation of the motor 61 (during low-speed rotation), the magnet 11 and the magnetic fluid 9 start to rotate together. This is because the force due to the viscosity of the magnetic fluid 9 and the frictional force that the magnet 11 acts on the moving road surface 2 d or the ceiling surface 1 b via the magnetic fluid 9 are larger than the centrifugal force due to the rotation of the housing 5. . A state in the housing 5 at this time is shown in FIG.

  When the rotational speed of the motor 61 increases, the magnet 11 receives a centrifugal force together with the magnetic fluid 9 and starts moving to the outer peripheral side in the moving space 14. As shown in FIG. 5B, when the rotational frequency of the motor 61 exceeds the resonance frequency of the vibration system and the phase of the unbalance 15 and the phase of the vibration system are almost reversed, the displacement direction A1 of the elastic body 62 is It is almost opposite to the position where the balance 15 is. At this time, the total gravity center position of all the magnets 11 receives a force in the direction of A1, and the magnetic fluid 9 also moves to the outer peripheral wall surface 2a side. Then, when the magnet 11 becomes almost stationary with respect to the rotation of the housing 5, that is, when the magnet 11 and the housing 5 come to rotate integrally, the unbalance is eliminated and the equilibrium is achieved. . The rotational speed of the disk D at this time is the rotational speed at the time of signal recording or reproduction, and is, for example, 200 to 7000 rpm, but is not limited to this range. The state in the housing at this time is shown in FIG.

  When the number of rotations of the motor 61 decreases and the operation ends, the magnet 11 and the magnetic fluid 9 located on the outer peripheral side move to the inner peripheral side of the inclined moving road surface 2d due to the influence of gravity. Thereby, the automatic balancing apparatus 10 returns to the state of FIG. Accordingly, it is possible to prevent a situation in which the magnetic fluid 9 sticks to the outer peripheral wall surface 2a due to surface tension or the like at the end of the operation, and the magnetic fluid 9 remains on the outer peripheral side, causing a malfunction in the operation.

  As described above, in the automatic balancing apparatus 10 according to the present embodiment, the magnet 11 has a high specific gravity like a conventional metal ball or the like, so that a balance can be reliably achieved. Further, since the magnetic fluid 9 adheres to the magnet 11 functioning as a balancer and the magnet 11 moves smoothly, noise caused by the movement of a conventional metal ball can be reduced.

  In particular, when the device equipped with the automatic balancing apparatus 10 is a device having a recording function, it is very advantageous to be able to reduce noise. This is because when a metal ball moves as a balancer as in the prior art, the noise may be recorded. Examples of the device having a recording function include a voice recorder and a portable audio / video recording device.

  If the specific gravity of the magnet 11 is high, even if the diameter of the housing 5 is small, the magnet 11 can exert a force to cancel the unbalance amount. As a result, downsizing of the automatic balancing apparatus 10 can be realized.

  Further, since the moving road surface 2d is provided so as to incline downward from the outer peripheral side toward the inner peripheral side, after the balance is achieved, the rotation of the housing 5 is decelerated or the operation of the automatic balancing device 10 is performed. After the completion, the magnetic fluid 9 can be quickly returned to the inner peripheral side by its own weight.

  FIG. 7 is a cross-sectional view showing an automatic balancing apparatus according to another embodiment of the present invention. In the present embodiment, the same members, functions, etc. of the automatic balancing apparatus 10 according to the embodiment shown in FIG.

  The ceiling surface 21 b of the housing 25 of the automatic balancing apparatus 20 according to this embodiment faces the inclined moving road surface 22 d provided on the case 22 substantially in parallel. That is, the ceiling surface 21b is also provided so as to be inclined downward from the outer peripheral side toward the inner peripheral side with respect to the horizontal plane. Even in such a configuration, the magnetic fluid 9 can be quickly returned to the inner peripheral side by the dead weight of the magnetic fluid 9 after the operation of the automatic balancing apparatus 10 is completed.

  The magnet 11 may have a cross-sectional shape in the rotation axis direction that is not a rectangle as shown in FIG. 3 but a parallelogram or other quadrangle as in the balancer 31 shown in FIG.

  The present invention is not limited to the embodiment described above, and various modifications are possible.

  The shape of the magnet 11 is an arc block shape, but is not limited thereto, and may be a cylindrical shape or a prism shape. In this case, as long as the magnets are magnetized in the direction of the rotation axis of the housing 5, the magnets can maintain a posture in which they repel each other.

  As long as the magnets 11 are magnetized so that the magnets 11 are not attracted to each other, the magnets 11 may be in any radial direction or circumferential direction.

It is a disassembled perspective view which shows the automatic balancing apparatus which concerns on one embodiment of this invention. It is sectional drawing of the automatic balancing apparatus shown in FIG. It is the sectional view on the AA line in FIG. It is sectional drawing which shows the disk drive device in which an automatic balancing apparatus is mounted. It is a figure which shows operation | movement of an automatic balancing apparatus in order, and is sectional drawing seen from the top. It is a figure which shows operation | movement of an automatic balancing apparatus in order, and is sectional drawing seen from the side. It is sectional drawing which shows the automatic balancing apparatus which concerns on other embodiment of this invention. It is sectional drawing which shows the automatic balancing apparatus provided with the magnet which concerns on other embodiment.

Explanation of symbols

D: Disk 1b, 21b Ceiling surface 2d, 22d ... Moving road surface 5, 25 ... Housing 9 ... Magnetic fluid 10, 20 ... Automatic balancing device 11, 31 ... Magnet (balancer)
22 ... Case 61 ... Motor 65 ... Turntable 100 ... Disk drive device

Claims (5)

With multiple magnets that function as balancers,
Magnetic fluid,
The magnet and the magnetic fluid have a moving road surface on which the magnet and the magnetic fluid move, are provided so as to be rotatable, and are provided so that the moving road surface is inclined downward from an outer peripheral side to an inner peripheral side of the rotation. And a housing for containing a magnetic fluid. The automatic balancing apparatus according to claim 1,
The housing is
An automatic balancing apparatus comprising a ceiling surface that faces the moving road surface and is inclined downward from the outer peripheral side toward the inner peripheral side. The automatic balancing apparatus according to claim 1,
Each of the magnets is formed in an arc block shape,
The housing has a horizontal ceiling surface facing the moving road surface,
The automatic balancing device, wherein the moving road surface is provided at an angle with respect to the ceiling surface so that the posture of each magnet is maintained. With multiple magnets that function as balancers,
Magnetic fluid,
The magnet and the magnetic fluid have a moving road surface on which the magnet and the magnetic fluid move, are provided so as to be rotatable, and are provided so that the moving road surface is inclined downward from an outer peripheral side to an inner peripheral side of the rotation. A housing containing magnetic fluid;
And a rotation mechanism for rotating the housing. A holding unit for holding a disc-shaped recording medium capable of recording a signal;
With multiple magnets that function as balancers,
Magnetic fluid,
The magnet and the magnetic fluid have a moving road surface on which the magnet and the magnetic fluid move, are provided so as to be rotatable, and are provided so that the moving road surface is inclined downward from an outer peripheral side to an inner peripheral side of the rotation. A disk drive device comprising: a housing that contains a magnetic fluid; and a drive mechanism that integrally rotates the holding portion and the housing.

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