JP2009254050A - Spindle motor and disk drive unit - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a spindle motor to which an unbalance correction mechanism is fixed. <P>SOLUTION: A spindle motor 10A includes rotating bodies (22, 31) bonded to a motor shaft 21 and having a substantially annular recess 31e for internally containing balls formed coaxially with the motor shaft 21, and a plurality of balance balls 33 which are contained movably in the recess for containing balls so that they are restricted to the inner circumferential side of the recess for containing balls during low speed rotation of the rotating bodies and moved to the outer circumferential side of the recess for containing balls during high speed rotation of the rotating bodies, wherein the recess 31e for containing balls has portions 32a for restricting the plurality of balance balls 33 during low speed rotation of the rotating bodies formed along an inner circumference over a predetermined angular range, and when the rotating bodies are bonded to the motor shaft while inclining, the portions 32a for restricting the balls are set on the side of a position where a virtual line K orthogonal to the motor shaft 21 touches the highest part of a height measuring surface (31a) in the rotating bodies (22, 31). <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a spindle motor provided with an unbalance correction mechanism unit integrally fixed to a motor shaft that can rotate from a low speed to a high speed, and the spindle motor is mounted in a housing to provide an unbalance correction mechanism unit. The present invention relates to a disk drive device that rotationally drives a disk mounted on a rotating body that constitutes a part of the disk.

  In general, a spindle motor is composed of a stator on the fixed side and a rotor on the rotation side with respect to the stator. Specifically, the spindle motor is integrated with a rotatable motor shaft and the motor shaft. A fixed rotating body, an annular magnet for motor driving fixed along the peripheral surface of the rotating body, and a plurality of motor driving coils facing the annular magnet for motor driving with a slight gap therebetween And a motor base on which the motor shaft is rotatably supported and the stator core is attached.

  This type of spindle motor is driven to rotate from a low speed to a high speed by mounting a disk such as an optical disk or a hard disk or a polycon mirror on a rotating body fixed to a rotatable motor shaft. An unbalanced state occurs when the center hole of the disc or the center hole of the polygon mirror is eccentric.

  In addition, CD (Compact Disc), DVD (Digital Versatile Disc) with higher density than CD, and BD (Blu-ray Disc) with higher density than DVD are rotated. In the disk drive device, the capacity of the information signal to the disk is increased, the speed of writing or reading of the information signal is increased, and the laser beam in the disk drive device is used to write characters on the label surface. A light scribe function for writing images has been developed.

In this type of disk drive device, the disk is integrally rotated with a rotating body fixed to the motor shaft of a spindle motor mounted inside the housing, and the disk is rotated at a low speed (40 min ⁻ There is a demand for stability free from vibration and surface vibration when rotated from ¹ ) to ultra-high speed rotation (10000 min ⁻¹ or more) such as during high-speed writing of information signals.

  Under these circumstances, when the disk or polygon mirror is rotated at a low speed, unstable rotation or deterioration of surface runout occurs due to the rotation of the motor shaft due to the clearance (backlash) generated between the motor shaft and the bearing. On the other hand, when the disk or polygon mirror is rotated at high speed, vibration and noise are easily deteriorated due to the unbalanced state including the rotating body.

In contrast to the above, there is an automatic balancing device that moves a balance sphere in an automatic balancing device fixed to a motor shaft corresponding to when the spindle motor rotates at a low speed and when it rotates at a high speed, and a motor using the same. (For example, refer to Patent Document 1).
JP 2001-258201 A

  9A and 9B are diagrams for explaining a conventional automatic balancing apparatus and a motor using the same, wherein FIG. 9A is a longitudinal sectional view, and FIG. 9B is a view taken along the line XX in FIG.

  The conventional automatic balancing apparatus shown in FIGS. 9A and 9B and the motor using the same are disclosed in the above-mentioned Patent Document 1 (Japanese Patent Laid-Open No. 2001-258201). This will be briefly described with reference to Patent Document 1.

  As shown in FIGS. 9A and 9B, in the conventional automatic balancing device and the motor using the same, the automatic balancing device (unbalance correction mechanism) is provided above the motor shaft 101 of the spindle motor 100. 110 is fixed, the automatic balancing device 110 is rotatable integrally with the motor shaft 101, and a disk table (not shown) for mounting a recording disk (not shown) on the upper side of the automatic balancing device 110. (Not shown) is provided.

  In the automatic balancing apparatus 110 described above, a plurality of balance spheres 112 are housed in a hollow balance housing section 111 in a state where they can freely move.

  At this time, a plurality of groove-like storage recesses 111a are radially arranged at substantially equal pitches along the circumference in the inner peripheral area of the hollow equilibrium storage portion 111 to store each balance sphere 112 during low-speed rotation. The rising wall surface on the inner peripheral side of each storage recess 111a constitutes an inner step 111b having a predetermined step, and each balance sphere 112 is formed by the step formed by the inner step 111b. The movement to the outside in the radial direction is restricted.

  On the other hand, an outer stepped portion 111d is provided in an annular shape in the outer peripheral region of the hollow balance accommodating portion 111 in order to hold each balance sphere 112 during high-speed rotation.

  In addition, a guide surface 111c having an inclination that descends from the outer step portion 111d toward the inner step portion 111b is provided between the inner step portion 111b and the outer step portion 111d formed in the balance storage portion 111. ing.

  In the automatic balancing device 110 configured as described above, a plurality of balancing spheres 112 in the balancing storage unit 111 are radially provided in the inner peripheral region during low-speed rotation that does not exceed the reference set rotational speed SR of the rotating body. By securely holding in the storage recess 111a, mutual contact between the balance spheres 112 is reliably prevented, and the generation and damage of the contact sound are favorably avoided.

  On the other hand, when the rotational speed of the rotating body exceeds the reference set rotational speed SR, each balance sphere 112 is moved over the step of the inner stepped portion 111b and reliably moved to the outer stepped portion 111d provided in the outer peripheral region. By automatically holding the recording disk (not shown) including the automatic balancing device 110 and correcting the unbalance of the recording disk (not shown) mounted on the disk table (not shown), the vibration generated at the time of high-speed rotation is corrected. It is disclosed to suppress.

  By the way, according to the conventional automatic balancing device and the motor using the same, the balancing spheres 112 are radially provided on the inner peripheral side of the balancing storage portion 111 when the automatic balancing device 110 rotates at a low speed integrally with the spindle motor 100. While being held in the plurality of storage recesses 111a, when the automatic balancing device 110 rotates at a high speed integrally with the spindle motor 100, an outer stepped portion 111d is provided in an annular shape on the outer peripheral side of the balancing storage portion 111. However, in the conventional automatic balancing apparatus 110, when a clearance (backlash) occurs between the motor shaft 101 of the spindle motor 100 and the bearing 102 that rotatably supports the motor shaft 101, Any consideration should be given to problems that occur when the automatic balancing device 110 is obliquely fixed to the motor shaft 101. Not.

  That is, when a clearance (backlash) occurs between the motor shaft 101 of the spindle motor 100 and the bearing 102 that rotatably supports the motor shaft 101, the motor is used particularly when a sintered oil-impregnated bearing is used as the bearing 102. Since the shaft 101 rotates in an irregular locus while tilting in the sintered oil-impregnated bearing, irregular shaft runout occurs.

  Further, when the automatic balancing device 110 is obliquely fixed to the motor shaft 101 and the disk mounted on the automatic balancing device 110 rotates at a low speed, the clearance of the motor balancing device 110 and the bearing 102 causes the clearance of the automatic balancing device 110. When tilted in the direction in which the tilt increases, the surface deflection of the disk increases and becomes larger, and there is a problem that information signal writing errors and reading errors are likely to occur on the disk.

  Therefore, a disk, a polygon mirror, etc. are integrated with a rotating body fixed to one end of the motor shaft of the spindle motor, and a second rotation speed (high speed) higher than the first rotation speed from the first rotation speed (low speed). If there is a clearance (backlash) between the motor shaft of the spindle motor and the bearing that rotatably supports the motor shaft, or the unbalance correction mechanism (automatic balancing device) In consideration of the case where the rotating body constituting a part is fixed obliquely with respect to the motor shaft, etc., when the rotating body is rotated at the first rotation speed, the rotation is kept quiet and highly accurate, and A spindle motor having an unbalance correction mechanism that can rotate with high precision without being in an unbalanced state when the rotating body is rotated at the second rotational speed, and the spindle motor in the casing Attached, disk drive disks mounted on a rotating member constituting a part of the unbalance correcting mechanism for driving the rotation is desired.

The present invention has been made in view of the above problems, and the first invention is a motor shaft that is rotationally driven from a first rotational speed to a second rotational speed higher than the first rotational speed. A rotating body fixed to one end side of the sphere, and having a spherical housing recess formed in a substantially annular shape coaxially with the motor shaft;
The sphere storage recess is movably stored, and when the rotator is rotated at the first rotation speed, the rotator is constrained to the inner peripheral side of the sphere storage recess. In a spindle motor comprising an unbalance correction mechanism portion composed of a plurality of balance spheres that move to the outer peripheral side in the sphere storage recess when rotated at the second rotational speed,
The concave portion for storing the spherical body has a spherical body constraining portion for constraining the plurality of balancing spheres when the rotating body is rotated at the first rotational speed within a predetermined angular range along the inner circumference. And when one surface of the rotating body is used as a height measuring surface for measuring the height of the rotating body corresponding to the inclination of the rotating body with respect to the motor shaft, The spherical body restraining portion is a spindle motor characterized in that an imaginary line orthogonal to the motor shaft is set on a position side in contact with a portion having the highest height in the one surface.

Further, the second invention is fixed to one end side of a motor shaft that is rotationally driven from the first rotational speed to the second rotational speed higher than the first rotational speed, and is used for storing the sphere inside. A rotating body having a recess formed in a substantially annular shape coaxially with the motor shaft;
The sphere storage recess is movably stored, and when the rotator is rotated at the first rotation speed, the rotator is constrained to the inner peripheral side of the sphere storage recess. In a spindle motor comprising an unbalance correction mechanism portion composed of a plurality of balance spheres that move to the outer peripheral side in the sphere storage recess when rotated at the second rotational speed,
The concave portion for storing the spherical body has a spherical body constraining portion for constraining the plurality of balancing spheres when the rotating body is rotated at the first rotational speed within a predetermined angular range along the inner circumference. The spherical body restraining portion is formed so as to include a circumferential position where an angle formed between one surface of the rotating body and the one end side of the motor shaft is the smallest. Is a spindle motor.

The third invention is the spindle motor of the first or second invention described above,
The balance sphere is formed of a magnetic sphere, and the sphere restraining portion is configured to fix an annular magnet magnetized only over the predetermined angle range to an inner peripheral side in the sphere housing recess. It is a spindle motor.

Moreover, 4th invention is a spindle motor of the above-mentioned 1st or 2nd invention,
The balance sphere is formed of a steel sphere, and the concave portion for storing the sphere is formed in a conical surface whose inner bottom surface decreases from the outer peripheral side toward the inner peripheral side, and on the inner peripheral side of the conical surface. The spindle motor is characterized in that the spherical body restraining portion is formed in a pocket shape over the predetermined angle range with respect to a convex surface formed by protruding the circumference other than the spherical body restraining portion upward.

The fifth invention is the spindle motor of the first or second invention described above,
The balance sphere is formed of a steel sphere, and the concave portion for storing the sphere is formed in a conical surface whose inner bottom surface decreases from the outer peripheral side toward the inner peripheral side, and on the inner peripheral side of the conical surface. The spindle motor is characterized in that the spherical body restraining portion is formed in a triangular concave groove shape over the predetermined angle range.

Furthermore, a sixth invention is mounted on the rotating body, wherein the spindle motor according to any one of the first to fifth inventions described above is mounted in a housing and fixed to one end side of the motor shaft. A disk drive device for rotating the disk,
When the disk is rotated at the first rotational speed integrally with the rotating body, the plurality of balance spheres stored in the spherical body storing recesses are set at a predetermined angle toward the inner peripheral side of the spherical body storing recesses. The plurality of balance spheres stored in the sphere storage recesses when the disk is rotated at the second rotational speed integrally with the rotating body while being restrained by the sphere restraining portion formed over a range. The disk drive device is characterized by correcting the unbalance due to the eccentricity of the disk by moving the disk to the outer peripheral side in the spherical body recess by centrifugal force.

  According to the spindle motor of the first aspect of the present invention, one end of the motor shaft that is rotationally driven from the first rotation speed to the high-speed rotation from the second rotation speed that is higher than the first rotation speed. A rotating body that is fixed to the side and has a spherical housing recess formed in a substantially annular shape coaxially with the motor shaft, and is stored movably in the spherical housing recess, and the rotating body has a first rotational speed ( A plurality of units that are constrained to the inner circumferential side in the spherical housing recess when rotated at a low speed, and that move to the outer circumferential side in the spherical housing recess when the rotating body is rotated at the second rotational speed (high speed). In the spindle motor provided with the unbalance correction mechanism portion composed of the balance spheres, the sphere storage recesses particularly have a sphere restraint for restraining a plurality of balance spheres when the rotator is rotated at the first rotational speed. Along the inner circumference When one surface of the rotator is used as a height measurement surface for measuring the height of the rotator corresponding to the inclination of the rotator with respect to the motor shaft, which is formed over a predetermined angle range. The spherical restraint portion is set on the position side where the imaginary line orthogonal to the motor axis is in contact with the highest part of one surface. As a result, the spindle motor axis and the motor axis are Considering the case where there is a clearance (backlash) between the bearings that are rotatably supported and the case where the rotating body that constitutes a part of the unbalance correction mechanism is fixed obliquely to the motor shaft. Thus, when the rotating body is rotated at the first rotation speed, the rotation is kept quiet and highly accurate, and when the rotating body is rotated at the second rotation speed, the unbalanced state is maintained with high accuracy. Can rotate.

  Further, according to the spindle motor of the second invention of the present invention, the motor shaft that is rotationally driven from the first rotation speed to the high-speed rotation from the second rotation speed that is higher than the first rotation speed. A rotator that is fixed to one end of the sphere, and that has a sphere storage recess formed in a substantially annular shape coaxially with the motor shaft, and is movably stored in the sphere storage recess, and the rotator is first rotated. When rotated at the speed (low speed), it is constrained to the inner peripheral side in the spherical housing recess, while when the rotating body is rotated at the second rotational speed (high speed), it moves to the outer peripheral side in the spherical housing recess. In the spindle motor provided with the unbalance correction mechanism unit composed of a plurality of balancing spheres, the sphere storage recesses in particular are for restraining the plurality of balancing spheres when the rotating body is rotated at the first rotational speed. Sphere restraint is the inner circumference The spherical body restraining portion is formed to include the circumferential position where the angle formed between one surface of the rotating body and one end of the motor shaft is the smallest. As a result, as in the case of the first invention described above, when a clearance (backlash) occurs between the motor shaft of the spindle motor and the bearing that rotatably supports the motor shaft, the unbalance correction mechanism section In consideration of the case where the rotating body constituting a part of the rotating body is fixed obliquely with respect to the motor shaft, when the rotating body is rotated at the first rotational speed, the rotation is kept quiet and highly accurate, In addition, when the rotating body is rotated at the second rotation speed, it can be rotated with high accuracy without being in an unbalanced state.

  According to the spindle motor of the third aspect of the invention, in particular, the balance sphere is made of a magnetic sphere, and the sphere constraining portion includes an annular magnet magnetized only over a predetermined angular range within the sphere housing recess. Since the effect of the first or second aspect of the invention is obtained due to being fixed to the peripheral side, a plurality of magnetic spheres can be provided to a sphere constraining portion having a simple structure when the rotator is rotated at the first rotation speed. It can be reliably adsorbed and restrained over an angular range.

  According to the spindle motor of the fourth aspect of the invention, in particular, the balance sphere is formed of a steel sphere, and the sphere storage recess is formed in a conical surface whose inner bottom surface decreases from the outer peripheral side toward the inner peripheral side. In addition, the spherical constraining part is formed on the inner peripheral side of the conical surface by denting it into a pocket over a predetermined angular range with respect to the convex surface formed by projecting the circumference other than the spherical constraining part upward. The effects of the first or second invention can be obtained, and when the rotating body is rotated at the first rotational speed, the plurality of steel spheres can be reliably secured to the sphere constraining portion having a simple structure over a predetermined angular range. Can be restrained.

  According to the spindle motor of the fifth aspect of the invention, in particular, the balance sphere is formed of a steel sphere, and the sphere storage recess is formed in a conical surface whose inner bottom surface decreases from the outer peripheral side toward the inner peripheral side. Since the spherical constraining portion is formed in a triangular concave groove shape over a predetermined angle range on the inner peripheral side of the conical surface, the effect of the first or second invention is obtained, and the rotating body is When rotated at the first rotational speed, the plurality of steel spheres can be reliably restrained over a predetermined angular range by a sphere restraining portion having a simple structure.

  Further, according to the disk drive device of the sixth invention, in particular, the rotation in which the spindle motor of any one of the first to fifth inventions is mounted in the housing and fixed to one end side of the motor shaft. When the disk mounted on the body is driven to rotate, when the disk is rotated at the first rotational speed integrally with the rotating body, a plurality of balance spheres stored in the sphere storing recesses are stored in the sphere storing recesses. When the disk is rotated at the second rotational speed integrally with the rotating body, the plurality of pieces stored in the spherical body storing recesses are restrained by the spherical body restraining portion formed on the inner peripheral side of the predetermined angular range. Since the balance sphere is moved to the outer peripheral side in the sphere storage recess by centrifugal force to correct the unbalance due to the eccentricity of the disk, the motor is rotated when the disk rotates at the first rotational speed. No unstable rotation of the disc or deterioration of surface run-out caused by the swinging of the disc occurs, so no information signal write error or read error occurs on the disc, while the disc rotates at the second rotational speed. When this occurs, the unbalance due to disk eccentricity can be automatically and satisfactorily corrected, so that the occurrence of vibration due to this unbalance is prevented and the shaft does not run out due to the well-known gyro effect. Since the shake does not deteriorate, the information signal can be recorded or reproduced favorably with respect to the disc.

  Hereinafter, an embodiment of a spindle motor and a disk drive device according to the present invention will be described in detail in the order of Embodiment 1, Embodiment 2, and Embodiment 3 with reference to FIGS.

FIG. 1 is an overall configuration diagram showing a disk drive device according to the present invention.
FIG. 2 is a view for explaining the spindle motor according to the first embodiment of the present invention, in which (a) is a longitudinal sectional view, (b) is a view taken in the direction of arrows XX in (a),
FIGS. 3A and 3B are diagrams schematically showing a state in which the turntable is fixedly tilted with respect to the motor shaft in the spindle motor according to the first embodiment of the present invention. FIG. 3A is a longitudinal sectional view, and FIG. XX view in (a),
4A and 4B are views schematically showing a state in which a turntable fixed to one end of the motor shaft of the spindle motor according to the first embodiment of the present invention rotates at a low speed.

  As shown in FIG. 1, in the disk drive device 1 according to the present invention, the spindle motor 10 </ b> A according to the first embodiment of the present invention is attached using a screw 3 inside a housing 2 formed in a substantially box shape. .

  And the unbalance correction mechanism part 30 which becomes the principal part of Example 1 is integrally attached to the upper part of the motor shaft 21 which is rotatable in the spindle motor 10A of Example 1 according to the present invention, and A turntable 31 constituting a part of the unbalance correction mechanism unit 30 is fixed to one end side of the motor shaft 21, and an optical disk, for example, can be detachably mounted as a disk D on the turntable 31. .

  In addition, below the disk D mounted on the turntable 31, laser light L is applied to the disk D that rotates integrally with the turntable 31 around the motor shaft 21 to write or read information signals. An optical pickup 4 to be performed is provided so as to be movable in the radial direction of the disk D.

  When a hard disk is applied as the disk D, a hub (not shown) for mounting the hard disk is fixed to one end side of the motor shaft 21 and information signals are written to or read from the housing 2. A magnetic head (not shown) to be performed may be provided so as to be movable in the radial direction of the disk D.

When the spindle motor 10A according to the first embodiment is started, the disk D on the turntable 31 fixed to one end of the motor shaft 21 is changed from the first rotation speed (40 min ⁻¹ ) to the first rotation speed. It can be driven to rotate at a high second rotational speed (10000 min ⁻¹ or more), and as described above, information is obtained when the disk D is rotated at the first rotational speed integrally with the turntable 31. While reading the signal or writing the signal, etc., when the disk D is rotated at the second rotation speed integrally with the turntable 31, the information signal is written at a high speed.

  In the following description, the first rotation speed is referred to as low speed, while the second rotation speed is referred to as high speed.

  In the disk drive device 1 according to the present invention, the spindle motor 10A according to the first embodiment according to the present invention is mounted in the housing 2. However, the present invention is not limited to this. The spindle motor 10B (FIG. 5) or the spindle motor 10C (FIG. 7) according to the third embodiment of the present invention may be mounted in the housing 2.

  Here, as shown in FIG. 2, the spindle motor 10 </ b> A according to the first embodiment of the present invention includes a stator S that is a fixed side and a rotor R that is a rotating side with respect to the stator S side. .

  First, in the spindle motor 10A of the first embodiment described above, on the stator S side which is a fixed side, a bearing holder 12 is provided on a motor base 11 using a galvanized steel plate or the like, and a cap 13 provided on the back side of the motor base 11. In addition, a bearing using a sintered oil-impregnated bearing (hereinafter referred to as a sintered oil-impregnated bearing), for example, is used to rotatably support the motor shaft 21 on the rotor R side in the bearing holder 12. 15) is fitted.

  At this time, the inner diameter of the sintered oil-impregnated bearing 15 is set to, for example, φ2.9995 mm, and the shaft diameter of the motor shaft 21 is set to, for example, φ2.9955 mm. Furthermore, the bearing span of the sintered oil-impregnated bearing 15 is set to 10.5 mm, for example.

  A stator core 17 in which magnetic steel plate materials are laminated is attached along the outer peripheral portion of the bearing holder 12, and a plurality of motor driving coils 18 are wound along the circumference of the stator core 17.

  On the other hand, on the rotor side of the rotation side, a cup-shaped rotor yoke 22 is fixed to an intermediate portion of the stainless steel motor shaft 21 by press-fitting or bonding, and the rotor yoke 22 is a disk formed in a substantially disk shape. The upper surface portion 22a and the cup portion 22b connected in an annular shape downward along the outer periphery of the disk-shaped upper surface portion 22a are integrally formed.

  In addition, an unbalance correction mechanism 30 that is a main part of the first embodiment is attached to the upper portion of the motor shaft 21 of the spindle motor 10 </ b> A so as to be rotatable integrally with the motor shaft 21.

  The unbalance correction mechanism 30 which is the main part of the first embodiment described above is fixed in contact with the lower surface of the turntable 31 on the turntable 31 fixed to the upper part of the motor shaft 21 of the spindle motor 10A and the motor shaft 21. In addition, a magnetic sphere housing recess 31e formed coaxially with the motor shaft 21 is closed on the lower surface side of the turntable 31 to form a bottom surface in the magnetic sphere housing recess 31e and a plurality of balance spheres described below. A rotating body (22, 31) rotating together with the motor shaft 21 together with a rotor yoke 22 for rolling the magnetic sphere 33, and an inner part of the rotating body (22, 31) in the magnetic sphere housing recess 31e. A plurality of magnetic spheres (balance spheres) that are movable within the annular magnet 32 housed on the circumferential side and the magnetic sphere housing recess 31e of the rotating body (22, 31). 3 is composed of a.

  In Example 1, a magnetic sphere rolling member (not shown) is fixed to the motor shaft 21 between the rotor yoke 22 and the turntable 31, and the lower surface side of the turntable 31 is attached to the magnetic sphere rolling member. The rotary body may be formed by closing the turntable 31 and the magnetic sphere rolling member.

  Here, the unbalance correction mechanism 30 that is a main part of the first embodiment will be described in detail. The turntable 31 is disposed above the disk-shaped upper surface portion 22a of the rotor yoke 22 fixed to the intermediate portion of the motor shaft 21. It is fixed to the motor shaft 21 by press-fitting or bonding.

  The turntable 31 described above is integrally formed using an aluminum material or a hard resin material, and a disk mounting surface 31a for mounting the disk D on the upper surface side of the turntable 31 is flat in a ring shape. A center hole fitting portion 31b for detachably fitting the center hole H of the disk D to the center portion to which the motor shaft 21 is fixed is formed to protrude upward from the disk mounting surface 31a. At the same time, a ring-shaped rubber plate 34 is mounted on the disk mounting surface 31a for mounting the disk D without sliding.

  On the back side of the turntable 31, an annular convex portion 31 c is formed at the central portion where the motor shaft 21 is fixed, and the lower surface of the annular convex portion 31 c abuts on the disk-shaped upper surface portion 22 a of the rotor yoke 22. ing.

  Further, on the inner peripheral side along the outer periphery of the annular convex portion 31 c of the turntable 31, a magnet housing concave portion 31 d for fixing and housing the annular magnet 32 is coaxial with the motor shaft 21. The lower surface of the annular magnet 32 housed in the magnet housing recess 31 d is configured to come into contact with the disk-shaped upper surface portion 22 a of the rotor yoke 22.

  Furthermore, a magnetic sphere housing recess 31e for movably housing a plurality of magnetic spheres 33 along the outer periphery of the magnet housing recess 31d of the turntable 31 is coaxial with the motor shaft 21 from the inner periphery toward the outer periphery. In general, the inside of the magnetic sphere housing recess 31e is a disk-shaped upper surface portion of the rotor yoke 22 so that the plurality of magnetic spheres 33 housed in the magnetic sphere housing recess 31e are not projected to the outside. A plurality of magnetic spheres 33 can roll along the disk-like upper surface portion 22a of the rotor yoke 22 by being closed by the 22a.

  At this time, the annular magnet 32 housed in the magnet housing recess 31d formed on the inner circumference side of the turntable 31 is a magnetic sphere restraint portion magnetized only over a predetermined angular range along the circumference. 32a and a non-magnetic sphere restraining portion 32b which is a part other than the magnetic sphere restraining portion 32a are connected to each other and formed in an annular shape.

  That is, the magnetic sphere restricting portion 32a of the annular magnet 32 described above has a plurality of magnetic spheres 33 formed using iron material or the like when the disk D rotates at a low speed integrally with the turntable 31. The magnetic sphere restraining portion 32a has a function for attracting and restraining to the side, and the N pole and the S pole over a predetermined angular range along the inner circumference of the turntable 31. Two poles are magnetized.

  The predetermined angular range of the magnetic sphere restraining portion 32a formed on the annular magnet 32 is set to an angle range occupied when the plurality of magnetic spheres 33 are attracted to the magnetic sphere restraining portion 32a and arranged in contact with each other. In the first embodiment, the turntable 31 when the outer diameter of the turntable 31 is set to, for example, φ28 mm, the diameter of the magnetic sphere 33 is, for example, φ2.5 mm, and the magnetic sphere 33 is constrained on the inner peripheral side. When the distance from the center of the magnetic sphere 33 to the center of the magnetic sphere 33 is set to 9.5 mm, when the eight magnetic spheres 33 having a diameter of 2.5 mm are arranged along the magnetic sphere restraining portion 32a, the predetermined angle described above The range is approximately 120 °.

  On the other hand, since portions other than the magnetic sphere restricting portion 32a in the annular magnet 32 are non-magnetic sphere restricting portions 32b that are not magnetized, the plurality of magnetic spheres 33 cannot be constrained to the inner peripheral side. It is like that.

  Further, the installation position in the circumferential direction of the magnetic spherical body restraining portion 32a of the annular magnet 32 housed in the magnet housing recess 31d of the turntable 31 is the motor of the turntable 31 fixed to the motor shaft 21 of the spindle motor 10A. After measuring the inclination with respect to the shaft 21 in advance, it is set according to the inclination of the turntable 31, and an annular shape so that the magnetic sphere restraining portion 32 a is positioned at the circumferential position set according to the inclination of the turntable 31. A magnet 32 is fixed in the magnet housing recess 31 d of the turntable 31.

  At this time, as shown in FIG. 3A, in the turntable 31 as a height measuring surface for measuring the height of the turntable 31 corresponding to the inclination of the turntable (rotating body) 31 with respect to the motor shaft 21. A disk mounting surface (one surface) 31a is used.

  Specifically, as shown in FIGS. 3A and 3B, when the turntable 31 is tilted and fixed to the motor shaft 21 of the spindle motor 10A, the magnetic sphere restricting portion 32a of the annular magnet 32 is provided. The imaginary line K that is perpendicular to the motor shaft 21 and is in contact with the outermost peripheral edge portion 31a1 of the disk mounting surface (one surface) 31a that is the height measuring surface is the highest in the circumferential direction. The center of a predetermined angle range of the magnetic sphere restraining portion 32a is set at a position in contact with the high part 31aH, and the virtual line KH in contact with the highest part 31aH and the lowest part 31aL. Since there is a difference of only the dimension h from the imaginary line KL in contact with the turntable 31, the turntable 31 is fixedly tilted with respect to the motor shaft 21 by this dimension h.

  That is, the magnetic sphere restraining portion 32a includes a circumferential position where the angle δ formed between one end of the disk mounting surface (one surface) 31a of the turntable 31 (rotating body) and the motor shaft 21 is the smallest. It will be formed. At this time, the above-described angle δ gradually changes along the circumferential direction around the motor shaft 21, and is the highest part 31aH of the disk mounting surface (one surface) 31a. While the corresponding angle δ takes the smallest value within 90 °, the angle δ corresponding to the region 31aL having the lowest height takes the largest value when it is 90 ° or more.

In addition, the magnetic attractive force of the magnetic sphere restricting portion 32a of the annular magnet 32 is such that the magnetic sphere 33 is provided on the inner peripheral side of the turntable 31 when the rotating bodies (22, 31) are stopped and when rotating at a low speed. When the rotational speed exceeds 400 min ⁻¹ during high speed rotation that is set so as to be gathered on the restraining portion 32 a side and generates vibration due to imbalance of the rotating bodies (51, 52) including the disk D, the magnetic sphere restraints Since the magnetic attractive force of the portion 32a is set to be lower than the centrifugal force of each magnetic sphere 33, each magnetic sphere 33 is released from the magnetic sphere restraining portion 32a side during high-speed rotation and is stored in the magnetic sphere of the turntable 31. It can move to the outer peripheral side in the concave portion 31e.

  Accordingly, the magnetic sphere housing recess 31e of the turntable 31 has a plurality of magnetic spheres when the rotating body (22, 31) composed of the rotor yoke 22 and the turntable 31 fixed to the motor shaft 21 of the spindle motor 10A is rotated at a low speed. A magnetic spherical body restraining portion 32a for restraining the motor 33 is formed over a predetermined angular range along the inner circumference, and the rotating bodies (22, 31) are inclined and fixed to the motor shaft 21. Sometimes, the magnetic sphere restraining portion 32a has the highest height among the disk mounting surfaces (one surface) 31a in which the imaginary line K orthogonal to the motor shaft 21 is the height measurement surface in the rotating body (22, 31). Since it is set on the position side in contact with the high portion 31aH, as a result, between the motor shaft 21 of the spindle motor 10A and the sintered oil-impregnated bearing 15 that rotatably supports the motor shaft 21. Rotation takes into account the occurrence of rear lances or the case where the rotating bodies (22, 31) constituting a part of the unbalance correction mechanism 30 are fixed obliquely to the motor shaft 21. When the body (22, 31) rotates at a low speed, the body (22, 31) can maintain a quiet and highly accurate rotation, and when the rotating body (22, 31) rotates at a high speed, the body (22, 31) can rotate with high accuracy without being in an unbalanced state.

  Next, the spindle motor 10A provided with the unbalance correction mechanism 30 which is the main part of the first embodiment configured as described above is mounted in the housing 2 and fixed to the motor shaft 21 of the spindle motor 10A. When the disk D is mounted on the table 31 to constitute the disk device 1 according to the present invention, the operation of the disk device 1 according to the present invention will be described with reference to FIGS.

  First, when the disk D rotates at a low speed integrally with the rotating body (22, 31) composed of the rotor yoke 22 and the turntable 31 fixed to the motor shaft 21 of the spindle motor 10A, the magnetic sphere housing recess 31e of the turntable 31 is rotated. The centrifugal force of the plurality of magnetic spheres 33 housed therein is the magnetic force of the magnetic sphere restraining portion 32a magnetized over a predetermined angular range among the annular magnets 32 provided on the inner peripheral side in the turntable 31. Since it is smaller than the attraction force, the plurality of magnetic spheres 33 are attracted and restrained by the magnetic sphere restraining portion 32 a, and the magnetic sphere restraining portion 32 a is tilted and fixed to the motor shaft 21. Since it is installed on the side of the mounting surface 31a having the highest height 31aH, there is no 0 between the motor shaft 21 and the sintered oil-impregnated bearing 15 as described above. As shown in FIGS. 4 (a) and 4 (b), when a clearance (backlash) of about 004 mm occurs and the shaft of the motor shaft 21 is swung while being tilted in the sintered oil-impregnated bearing 15, as shown in FIGS. The plurality of magnetic spheres 33 adsorbed by the magnetic sphere restraining portion 32a of the magnet 32 cause a centrifugal force in the direction of the highest portion 31aH with respect to the disk mounting surface 31a, and the vibration is always performed with the high position outward. Since it rotates while rotating, the surface runout of the disk mounting surface 31a of the turntable 31 fixed to the motor shaft 21 is canceled and reduced, and the disk mounted on the disk mounting surface 31a via the ring-shaped rubber plate 34 is reduced. Since the deterioration of the surface deflection of D can be prevented, no information signal write error or read error occurs on the disk D.

  On the other hand, when the disk D rotates at a high speed integrally with the rotating bodies (22, 31), the centrifugal force of the plurality of magnetic spheres 33 housed in the magnetic sphere housing recesses 31e of the turntable 31 Since the magnetic attractive force of the magnetic sphere restricting portion 32a magnetized over a predetermined angle range among the annular magnets 32 provided on the inner peripheral side is larger, the plurality of magnetic spheres 33 are formed by the magnetic sphere restricting portion 32a. It is released from the attracted state and moves to the outer peripheral side in the magnetic sphere housing recess 31e of the turntable 31 to reach the outer peripheral wall 31e1, and the imbalance due to the eccentricity of the disk D is offset in the magnetic sphere storage recess 31e of the turntable 31. Since the correction is automatically and satisfactorily corrected so as to cancel out by the plurality of magnetic spheres 33 moved to the outer peripheral side, generation of vibration due to this unbalance is prevented.

  Further, when the disk D rotates at a high speed integrally with the rotating body (22, 31), the shaft does not run out due to the well-known gyro effect, and the surface runout of the turntable 31 does not deteriorate. Thus, the information signal can be recorded or reproduced satisfactorily.

  The known gyro effect described above generally means that the rotation axis (SpinAxis) is always kept in a fixed direction with respect to space unless an external force is applied to a rotating body (rotor) that rotates at high speed. When an external force is applied to the body, it means the property of rotating around an axis perpendicular to the axis.

5A and 5B are diagrams for explaining a spindle motor according to a second embodiment of the present invention, in which FIG. 5A is a longitudinal sectional view, and FIG. 5B is a view taken along the line XX in FIG.
6A and 6B are diagrams schematically showing a state in which the turntable is tilted and fixed with respect to the motor shaft in the spindle motor according to the second embodiment of the present invention. FIG. 6A is a longitudinal sectional view, and FIG. These are the XX arrow directional views in (a).

  In the spindle motor 10B according to the second embodiment of the present invention shown in FIGS. 5 (a) and 5 (b), the unbalance correction mechanism 40, which is the main part of the second embodiment, is integrally formed on the upper portion of the motor shaft 21. Only the attached points differ from the first embodiment, and different constituent members from the first embodiment will be described with new reference numerals.

  The unbalance correction mechanism 40, which is the main part of the second embodiment described above, is fixed in contact with the lower surface of the turntable 41 on the turntable 41 fixed to the upper portion of the motor shaft 21 of the spindle motor 10B. Further, a steel ball housing recess 41d formed coaxially with the motor shaft 21 is closed on the lower surface side of the turntable 41 to form a bottom surface in the steel ball housing recess 41d, and a plurality of the below-described types of balance spheres. A rotating body (41, 42) that rotates together with the steel shaft rolling member 42 for rolling the steel ball body 43 together with the motor shaft 21, and a recess for storing the steel ball body of the rotating body (41, 42) It comprises a plurality of steel spheres (balance spheres) 43 that are movable within 41d.

  Here, the unbalance correction mechanism 40, which is a main part of the second embodiment, will be described in detail. The steel ball rolls above the disk-shaped upper surface portion 22a of the rotor yoke 22 fixed to the intermediate portion of the motor shaft 21. The member 42 is fixed to the motor shaft 21 by press-fitting or bonding, and the turntable 41 is fixed to the motor shaft 21 by press-fitting or bonding above the steel ball rolling member 42.

  Similarly to the first embodiment, the above-described turntable 41 is also integrally formed using an aluminum material or a hard resin material, and a disk mounting surface for mounting the disk D on the upper surface side of the turntable 41. 41a is formed flat in a ring shape, and a center hole fitting portion 41b for removably fitting the center hole H of the disk D to the center portion where the motor shaft 21 is fixed is located above the disk mounting surface 41a. And a ring-shaped rubber plate 44 for mounting the disk D on the disk mounting surface 41a without sliding.

  Further, on the back surface side of the turntable 41, an annular convex portion 41c is formed at the central portion where the motor shaft 21 is fixed, and the steel ball rolling member 42 whose lower surface of the annular convex portion 41c is fixed to the motor shaft 21. Is in contact with an annular convex portion 42a formed at the central portion of the.

  Further, a steel ball storage recess 41d for movably storing a plurality of steel balls 43 along the outer periphery of the annular projection 41c of the turntable 41 is coaxial with the motor shaft 21 from the inner periphery toward the outer periphery. In general, the bottom surface of the steel ball storage recess 41d is formed into a steel ball rolling member so that the plurality of steel balls 43 stored in the steel ball storage recess 41d do not jump out. A plurality of steel spheres 43 roll along the conical surface 42b of the steel sphere rolling member 42 by being closed by a conical surface 42b formed so as to become lower from the outer peripheral side toward the inner peripheral side. It is possible.

  Further, on the inner peripheral side of the conical surface 42b of the steel ball rolling member 42, a non-steel ball that is a part other than the steel ball restraining part 42b1 and the steel ball restraining part 42b1 over a predetermined angular range along the circumference. The restraint portion 42b2 is formed to be connected.

  That is, the steel sphere restraining portion 42b1 formed on the inner peripheral side of the conical surface 42b of the steel sphere rolling member 42 allows the plurality of steel spheres 43 to be turned into the turntable 41 when the disk D rotates at a low speed integrally with the turntable 41. This steel ball body restraining portion 42b1 has a convex surface which will be described later along the inclination of the conical surface 42b over a predetermined angular range along the circumference. It is recessed in a pocket shape with respect to the spherical body restraining part 42b2.

  In addition, a predetermined angle range of the steel ball restraint portion 42b1 formed in the pocket shape on the inner peripheral side of the conical surface 42b of the steel ball rolling member 42 is such that a plurality of steel ball bodies 43 are restrained in the steel ball restraint portion 42b1. It is preferable to set the angle range occupied when aligned in contact with each other. In this second embodiment, the outer diameter of the turntable 41 is set to, for example, φ28 mm, and the diameter of the steel ball 43 is set to, for example, φ2.5 mm. When the six steel balls 43 having a diameter of 2.5 mm are arranged along the steel ball restraining part 42b1, the predetermined angle range described above is approximately 120 °.

  On the other hand, the non-steel sphere restraining portion formed as a convex surface having a slightly higher height than the steel sphere restraining portion 42b1 on the inner peripheral side of the conical surface 42b of the steel sphere rolling member 42 except for the steel sphere restraining portion 42b1. Since it is 42b2, the several steel ball body 43 cannot be restrained to the inner peripheral side.

  Further, the installation position of the steel ball restraint portion 42b1 formed in a pocket shape on the inner peripheral side of the conical surface 42b of the steel ball rolling member 42 is such that the turntable 41 fixed to the motor shaft 21 of the spindle motor 10B is inclined. After the measurement in advance, the turntable 41 is set according to the inclination of the turntable 41. After the plurality of steel balls 43 are stored in the steel ball storage recess 41d of the turntable 41, the turntable 41 is set according to the inclination of the turntable 41. The steel ball rolling member 42 is fixed to the motor shaft 21 so that the steel ball restraining portion 42b1 is located at the position.

  At this time, as shown in FIG. 6A, in the turntable 41 as a height measurement surface for measuring the height of the turntable 41 corresponding to the inclination of the turntable (rotating body) 41 with respect to the motor shaft 21. A disk mounting surface (one surface) 41a is used.

  Specifically, as shown in FIGS. 6A and 6B, when the turntable 41 is tilted and fixed to the motor shaft 21 of the spindle motor 10B, the conical surface 42b of the steel ball rolling member 42 is obtained. The installation position in the circumferential direction of the steel ball restraint portion 42b1 formed in a pocket shape on the inner peripheral side of the disk is perpendicular to the motor shaft 21 and is on the disk mounting surface (one surface) 41a that becomes the height measurement surface. The imaginary line K in contact with the outermost peripheral edge portion 41a1 is set so that the center of the predetermined angular range of the steel ball restraint portion 42b1 is located at the position in contact with the portion 41aH having the highest height. Since there is a difference of only dimension h between the imaginary line KH in contact with the high part 41aH and the imaginary line KL in contact with the lowest part 41aL, the turntable 41 is inclined with respect to the motor shaft 21 by this dimension h. Fixed It will be.

  That is, the steel ball restraint portion 42b1 includes a circumferential position where the angle δ formed between one end side of the disk mounting surface (one surface) 41a of the turntable 41 (rotating body) and the motor shaft 21 is the smallest. It will be formed. At this time, the angle δ described above gradually changes along the circumferential direction with the motor shaft 21 as the center, and the portion 41aH having the highest height among the disk mounting surfaces (one surface) 41a. While the corresponding angle δ takes the smallest value within 90 °, the angle δ corresponding to the portion 41aL having the lowest height takes the largest value when it is 90 ° or more.

  In addition, the inclination angle α of the conical surface 42b of the steel ball rolling member 42 is set such that the plurality of steel balls 43 are provided on the inner peripheral side of the steel ball rolling member 42 when the rotating bodies (41, 42) are stopped and when rotating at a low speed. In addition, the centrifugal force of each steel sphere 43 is conical surface during high-speed rotation in which vibration is generated due to unbalance of the rotating bodies (41, 42) including the disk D. Since it is set so as to exceed the gravity of each steel sphere 43 due to the inclination of 42b, each steel sphere 43 is released from the steel sphere restraining portion 42b1 side during high speed rotation, and the steel sphere housing recess 41d of the turntable 41 is provided. It can move to the inner periphery.

  That is, in order for the centrifugal force of each steel sphere 43 to exceed the gravity of each steel sphere 43 due to the inclination of the conical surface 42b, the inclination angle α of the conical surface 42b of the steel sphere rolling member 42 is expressed by the following formula 1 Calculate from

[Equation 1]
tan α <mrω ² / mg (Formula 1)
Where m: mass of the steel sphere 43, r: distance from the center of rotation of the rotating body (41, 42) to the center of the steel sphere 43, ω: rotational speed of the rotating body (41, 42), g: gravitational acceleration ( = 9.8 m / s ² ).

At this time, when the rotating body (41, 42) is stopped, the center position of the steel ball 43 when stationary is 3 mm from the center of the rotating body (41, 42), and the rotating body (41, 42). In order for each steel sphere 43 to move to the outer peripheral side exceeding 400 min ⁻¹ (= 41.9 rad / s), the slope of the conical surface 42b of the steel sphere rolling member 42 is obtained from the above equation 1. The angle α may be set to 28 °.

  Therefore, from the above, the steel ball storage recess 41d of the turntable 41 is in the low speed rotation of the rotating body (41, 42) composed of the turntable 41 fixed to the motor shaft 21 of the spindle motor 10B and the steel ball rolling member 42. A steel ball restraint portion 42b1 for restraining the plurality of steel ball bodies 43 is formed over a predetermined angular range along the inner circumference, and the rotating bodies (41, 42) are tilted toward the motor shaft 21. When the steel ball restraint part 42b1 is fixed, the imaginary line K perpendicular to the motor shaft 21 is a disk mounting surface (one surface) 41a that becomes a height measuring surface in the rotating body (41, 42). Since it is set on the position side where it comes into contact with the highest part 41aH, as a result, there is a coupling between the motor shaft 21 of the spindle motor 10B and the sintered oil-impregnated bearing 15 that rotatably supports the motor shaft 21. Rotation takes into account the occurrence of lances or the case where the rotating bodies (41, 42) constituting a part of the unbalance correction mechanism 40 are fixed obliquely to the motor shaft 21. When the body (41, 42) is rotated at a low speed, the body (41, 42) can maintain a quiet and highly accurate rotation, and when the rotating body (41, 42) is rotated at a high speed, the body (41, 42) can rotate with high accuracy without being in an unbalanced state.

  Next, the spindle motor 10B provided with the unbalance correction mechanism 40, which is the main part of the second embodiment configured as described above, is mounted in the housing 2 and fixed to the motor shaft 21 of the spindle motor 10B. When the disk D is mounted on the table 41 and the disk apparatus 1 according to the present invention is configured, the operation of the disk apparatus 1 according to the present invention will be described with reference to FIGS.

  First, when the disk D rotates at a low speed integrally with a rotating body (41, 42) comprising a turntable 41 and a steel ball rolling member 42 fixed to the motor shaft 21 of the spindle motor 10B, the steel ball of the turntable 41 is rotated. The plurality of steel spheres 43 housed in the housing recess 41d are recessed in a pocket shape with respect to the non-steel sphere restraining portion 42b2 having a convex surface on the inner peripheral side due to the inclination of the conical surface 42b of the steel sphere rolling member 42. The steel ball restraint portion 42b1 is constrained by a steel ball restraint portion 42b1 provided over a predetermined angle range. The steel ball restraint portion 42b1 is the most of the disk mounting surface 41a of the turntable 41 that is fixedly tilted with respect to the motor shaft 21. Since it is installed on the part 41aH side where the height is high, the clearance (backlash) of about 0.004 mm as described above is provided between the motor shaft 21 and the sintered oil-impregnated bearing 15. When the motor shaft 21 tilts in the sintered oil-impregnated bearing 15 and the shaft swings, the same as described with reference to FIGS. 4A and 4B in the first embodiment. The centrifugal force in the direction of the highest portion 41aH acts on the disk mounting surface 41a by the plurality of steel spheres 43 constrained by the steel sphere restraining portions 41b1 of the steel sphere rolling member 42, and the high position is always outside. In this state, the motor shaft 21 follows the center of rotation of the sintered oil-impregnated bearing 15, thereby reducing runout of the disk mounting surface 41 a of the turntable 41 fixed to the motor shaft 21. Since it is possible to prevent deterioration of surface deflection of the disk D mounted on the disk mounting surface 41a via the ring-shaped rubber plate 44, information signal write errors and read errors are recorded on the disk D. Over it does not occur.

  On the other hand, when the disk D rotates at a high speed integrally with the rotating bodies (41, 42), the centrifugal force of the plurality of steel spheres 43 accommodated in the steel sphere accommodating recesses 41d of the turntable 41 is the steel sphere rolling member. 42, which is greater than the gravity of each steel sphere 43 due to the inclination of the conical surface 42b of the 42, so that the plurality of steel spheres 43 are released from the constrained state by the steel sphere constraining part 42b1, and the inside of the steel sphere accommodating recess 41d of the turntable 41 It moves to the outer peripheral side, reaches the outer peripheral wall 41d1, and automatically cancels the unbalance due to the eccentricity of the disk D by the plurality of steel spheres 43 moved to the outer peripheral side in the steel ball storage recess 41d of the turntable 41. Since the correction is performed satisfactorily, generation of vibration due to this unbalance is prevented.

  Further, when the disk D rotates at a high speed integrally with the rotating body (41, 42), the shaft runout does not occur due to the known gyro effect, and the surface runout of the turntable 41 does not deteriorate. Thus, the information signal can be recorded or reproduced satisfactorily.

7A and 7B are diagrams for explaining a spindle motor according to a third embodiment of the present invention, in which FIG. 7A is a longitudinal sectional view, and FIG. 7B is a view taken along the line XX in FIG.
FIG. 8 is a diagram schematically showing a state in which the turntable is fixedly tilted with respect to the motor shaft in the spindle motor according to the third embodiment of the present invention, where (a) is a longitudinal sectional view and (b). These are the XX arrow directional views in (a).

  In the spindle motor 10C according to the third embodiment of the present invention shown in FIGS. 7A and 7B, the unbalance correction mechanism 50, which is the main part of the third embodiment, is integrally formed on the upper portion of the motor shaft 21. Only the attached points differ from the first and second embodiments, and different constituent members from the first and second embodiments will be described with new reference numerals.

  The unbalance correction mechanism 50, which is the main part of the third embodiment, is fixed on the turntable 51 fixed to the upper part of the motor shaft 21 of the spindle motor 10C and the lower surface of the turntable 51 on the motor shaft 21. In addition, a steel ball housing recess 51d formed coaxially with the motor shaft 21 is closed on the lower surface side of the turntable 51 to form a bottom surface in the steel ball housing recess 51d, and a plurality of balance spheres described below. A rotating body (51, 52) that rotates together with the motor shaft 21 together with a steel ball rolling member 52 for rolling the steel ball 53, and a recess for storing the steel ball of the rotating body (51, 52) A plurality of steel spheres (balance spheres) 53 that are movable within 51d.

  Here, the unbalance correction mechanism 50 which is a main part of the third embodiment will be described in detail. The steel ball rolls above the disk-shaped upper surface portion 22a of the rotor yoke 22 fixed to the intermediate portion of the motor shaft 21. The member 52 is fixed to the motor shaft 21 by press-fitting or bonding, and the turntable 51 is fixed to the motor shaft 21 by press-fitting or bonding above the steel ball rolling member 52.

  Similarly to the first and second embodiments, the above-described turntable 51 is also integrally formed using an aluminum material or a hard resin material, and a disk for mounting the disk D on the upper surface side of the turntable 51. The mounting surface 51a is formed flat in a ring shape, and a center hole fitting portion 51b for removably fitting the center hole H of the disk D to the central portion where the motor shaft 21 is fixed is provided from the disk mounting surface 51a. And a ring-shaped rubber plate 54 for bonding the disk D without sliding on the disk mounting surface 51a.

  Further, similarly to the second embodiment, an annular convex portion 51c is formed on the rear surface side of the turntable 51 at the central portion where the motor shaft 21 is fixed, and the lower surface of the annular convex portion 51c is fixed to the motor shaft 21. The steel ball rolling member 52 is in contact with an annular convex portion 52a formed at the central portion.

  Further, a steel ball storage recess 51d for storing a plurality of steel balls 53 movably along the outer periphery of the annular convex portion 51c of the turntable 51 is coaxial with the motor shaft 21 from the inner periphery toward the outer periphery. In general, the bottom surface of the steel ball storage recess 51d is formed into a steel ball rolling member so that the plurality of steel balls 53 stored in the steel ball storage recess 51d do not jump out. A plurality of steel spheres 53 roll along the conical surface 52b of the steel ball rolling member 52, which is closed by a conical surface 52b formed so as to become lower from the outer peripheral side to the inner peripheral side. It is possible.

  Further, on the inner peripheral side of the conical surface 52b of the steel ball rolling member 52, a steel ball constraining portion 52b1 extending over a predetermined angular range along the circumference is recessed from the conical surface 52b and formed in a triangular concave groove shape. In addition, the inner peripheral portion other than the steel ball body restraining portion 52b1 remains the conical surface 52b.

  That is, the steel ball restraint portion 52b1 formed in a triangular concave groove shape over a predetermined angle range on the inner peripheral side of the conical surface 52b of the steel ball rolling member 52 has the disk D rotated at a low speed integrally with the turntable 51. Sometimes, it has a function for restraining the plurality of steel balls 53 to the inner peripheral side of the turntable 51.

  In addition, a predetermined angle range of the steel ball restraint portion 52b1 formed in a triangular concave groove shape on the inner peripheral side of the conical surface 52b of the steel ball rolling member 52 is such that a plurality of steel balls 53 are restrained in the steel ball restraint portion 52b1. It is preferable to set the angle range that occupies when arranged in contact with each other. In this third embodiment, the outer diameter of the turntable 51 is set to, for example, φ28 mm, and the diameter of the steel ball 53 is set to, for example, φ2.5 mm. When set, when the six steel spheres 53 having a diameter of φ2.5 mm are arranged along the steel sphere constraining portion 52b1, the predetermined angle range described above is approximately 120 °.

  On the other hand, since the part other than the steel sphere restraining portion 52b1 remains the conical surface 52b on the inner peripheral side of the conical surface 52b of the steel sphere rolling member 52, the plurality of steel spheres 53 are constrained to the inner peripheral side. Can not be.

  Further, the installation position of the steel ball restraint portion 52b1 formed in a triangular concave groove shape on the inner peripheral side of the conical surface 52b of the steel ball rolling member 52 is set at the position of the turntable 51 fixed to the motor shaft 21 of the spindle motor 10C. After the inclination is measured in advance, it is set according to the inclination of the turntable 51. After the plurality of steel balls 53 are stored in the steel ball storage recess 51d of the turntable 51, the turntable 51 is set according to the inclination of the turntable 51. The steel ball rolling member 52 is fixed to the motor shaft 21 so that the steel ball restraining part 52b1 is located at the set position.

  At this time, as shown in FIG. 8A, in the turntable 51 as a height measuring surface for measuring the height of the turntable 51 corresponding to the inclination of the turntable (rotating body) 51 with respect to the motor shaft 21. A disk mounting surface (one surface) 51a is used.

  Specifically, as shown in FIGS. 8A and 8B, when the turntable 51 is tilted and fixed to the motor shaft 21 of the spindle motor 10C, the conical surface 52b of the steel ball rolling member 52 is obtained. The circumferential position of the steel ball restraint 52b1 formed in the shape of a triangular concave groove on the inner peripheral side of the disk is perpendicular to the motor shaft 21 and is a disk mounting surface (one surface) that serves as a height measurement surface. The imaginary line K in contact with the outermost peripheral edge 51a1 of 51a is set so that the center of the predetermined angular range of the steel ball restraint 52b1 is located at the position in contact with the highest part 51aH. Since there is a difference of only dimension h between the imaginary line KH in contact with the part 51aH having a high height and the imaginary line KL in contact with the part 51aL having the lowest height, the turntable 51 is relative to the motor shaft 21 by this dimension h. Tilted and fixed It will be.

  That is, the steel ball body restraining part 52b1 includes a circumferential position where an angle δ formed between one end side of the disk mounting surface (one surface) 51a of the turntable 51 (rotating body) and the motor shaft 21 is the smallest. It will be formed. At this time, the angle δ described above gradually changes along the circumferential direction with the motor shaft 21 as the center, and the height 51 of the disk mounting surface (one surface) 51a is the highest. While the corresponding angle δ takes the smallest value within 90 °, the angle δ corresponding to the portion 51aL having the lowest height takes the largest value when it is 90 ° or more.

  Further, the inclination angle β of the conical surface 52b of the steel ball rolling member 52 and the inclination angle θ on the outer peripheral side of the steel ball constraining portion 52b1 formed in the shape of a triangular concave groove on the conical surface 52b are the rotating bodies (51, 52). The rotating body including the disk D is set so that the plurality of steel balls 53 are gathered on the steel ball restraining part 52b1 provided on the inner peripheral side of the steel ball rolling member 52 at the time of stopping and rotating at a low speed. 51, 52) At the time of high-speed rotation in which vibration is generated due to unbalance of 51, 52), the centrifugal force of each steel sphere 53 is caused by the gravity of each steel sphere 53 due to the inclination of the conical surface 52b and Since it is set so as to exceed the gravity of 53, each steel ball 53 is released from the steel ball restraint 52b1 side during high-speed rotation and can move to the outer peripheral side in the steel ball housing recess 51d of the turntable 51. Set up as It has been determined.

  At this time, as apparent from FIG. 7, the inclination angle θ on the outer peripheral side of the steel ball constraining portion 52 b 1 formed in a triangular concave groove shape on the conical surface 52 b is the inclination of the conical surface 52 b of the steel ball rolling member 52. Since the angle β is larger than the angle β, the inclination angle β of the conical surface 52b of the steel ball rolling member 52 is made smaller than the inclination angle θ after the inclination angle θ on the outer peripheral side of the steel ball constraining portion 52b1 is obtained first. You only have to set it.

That is, in order for the centrifugal force of each steel sphere 53 to exceed the gravity of each steel sphere 53 due to the inclination on the outer peripheral side of the steel sphere restraint 52b1 formed in the triangular concave groove on the conical surface 52b, the steel sphere restraint The inclination angle θ on the outer peripheral side of 52b1 can be calculated from the above-described equation 1, and the number of rotations of the rotating bodies (51, 52) when each steel ball 53 is moved 4 mm from the stationary center position to the outer peripheral side. For example, when it is desired to set the ^value to 500 min ⁻¹ (= 52.4 rad / s), the inclination angle θ on the outer peripheral side of the steel ball restraint portion 52b1 may be set to 48 °.

  Therefore, from the above, the steel ball storage recess 51d of the turntable 51 is at the time of low-speed rotation of the rotary body (51, 52) composed of the turntable 51 fixed to the motor shaft 21 of the spindle motor 10C and the steel ball rolling member 52. A steel ball body restraining part 52b1 for restraining the plurality of steel ball bodies 53 is formed over a predetermined angular range along the inner circumference, and the rotating bodies (51, 52) are inclined toward the motor shaft 21. The steel ball restraint portion 52b1 has a phantom line K perpendicular to the motor shaft 21 in the rotating body (51, 52) of the disk mounting surface (one surface) 51a that becomes the height measurement surface when the steel ball restraining portion 52b1 is fixed. Since it is set at the position in contact with the portion 51aH having the highest height, as a result, there is a clearance between the motor shaft 21 of the spindle motor 10C and the sintered oil-impregnated bearing 15 that rotatably supports the motor shaft 21. Rotation takes into account the occurrence of lances or the case where the rotating bodies (51, 52) constituting a part of the unbalance correction mechanism 50 are fixed obliquely to the motor shaft 21. When the body (51, 52) rotates at a low speed, the body (51, 52) can maintain a quiet and highly accurate rotation, and when the rotating body (51, 52) rotates at a high speed, the body (51, 52) can rotate with high accuracy without being in an unbalanced state.

  Next, the spindle motor 10C provided with the unbalance correction mechanism 50, which is the main part of the third embodiment configured as described above, is mounted in the housing 2 and fixed to the motor shaft 21 of the spindle motor 10C. When the disk D is mounted on the table 51 to constitute the disk device 1 according to the present invention, the operation of the disk device 1 according to the present invention will be described with reference to FIGS.

  First, when the disk D rotates at a low speed integrally with a rotating body (51, 52) comprising a turntable 51 and a steel ball rolling member 52 fixed to the motor shaft 21 of the spindle motor 10C, the steel ball of the turntable 51 is rotated. A plurality of steel spheres 53 housed in the housing recess 51d are provided with a steel sphere restraint provided in a triangular concave groove shape over a predetermined angle range on the inner circumferential side due to the inclination of the conical surface 52b of the steel sphere rolling member 52. The steel ball restraint portion 52b1 is installed on the side of the portion 51aH having the highest height among the disc mounting surfaces 51a of the turntable 51 fixed to the motor shaft 21 while being restrained by the portion 52b1. Therefore, the clearance (backlash) of about 0.004 mm as described above is generated between the motor shaft 21 and the sintered oil-impregnated bearing 15, and the motor shaft 21 is inclined in the sintered oil-impregnated bearing 15. However, when the shaft runout occurs, it is restrained by the steel ball restraining portion 51b1 of the steel ball rolling member 52 in substantially the same manner as described in the first embodiment with reference to FIGS. 4 (a) and 4 (b). The centrifugal force in the direction of the portion 51aH having the highest height acts on the disk mounting surface 51a by the plurality of formed steel balls 53, and the motor shaft 21 rotates while swinging in a state where the high position is always outside. The vibration of the disk mounting surface 51a of the turntable 51 fixed to the motor shaft 21 is reduced along the rotation center of the sintered oil-impregnated bearing 15, and the ring-shaped rubber plate 54 is placed on the disk mounting surface 51a. In this way, it is possible to prevent deterioration of the surface vibration of the disk D mounted therethrough, so that no information signal writing error or reading error occurs on the disk D.

  On the other hand, when the disk D rotates at a high speed integrally with the rotating bodies (51, 52), the centrifugal force of the plurality of steel balls 53 housed in the steel ball housing recesses 51d of the turntable 51 is the steel ball rolling member. 52, which exceeds the gravity of each steel sphere 53 due to the inclination of the conical surface 52b and the gravity of each steel sphere 53 due to the inclination on the outer peripheral side of the steel sphere constraining portion 52b1 recessed in a triangular groove shape from the conical surface 52b. The steel ball 53 is released from the restrained state by the steel ball restraining portion 52b1 and moves to the outer peripheral side in the steel ball storing recess 51d of the turntable 51 to reach the outer peripheral wall 51d1, and the unbalance due to the eccentricity of the disk D is turned. Since the correction is automatically and satisfactorily compensated by the plurality of steel spheres 53 moved to the outer peripheral side in the steel sphere accommodating recess 51d of the table 51, the occurrence of vibration due to this unbalance It is prevented.

  Further, when the disk D rotates at a high speed integrally with the rotating body (51, 52), the shaft does not run out due to the known gyro effect, and the surface runout of the turntable 51 does not deteriorate. Thus, the information signal can be recorded or reproduced satisfactorily.

  In the first to third embodiments described above, any of the spindle motors 10A to 10C according to the first to third embodiments according to the present invention is mounted in the housing 2, and the motor shafts 21 of these spindle motors 10A to 10C are mounted. Although the disk drive device 1 that rotates the disk D mounted on the turntables 31, 41, and 51 fixed to the disk drive device 1 has been described, the present invention is not limited to this, but the illustration is omitted here, but the first to third embodiments are omitted. The technical idea of the present invention can also be applied to a polygon mirror driving device in which a hub serving as a rotating body is fixed to each motor shaft 21 of each of the spindle motors 10A to 10C and a polygon mirror mounted on the hub is driven to rotate. .

  In the case of this polygon mirror driving device, when the polygon mirror is rotated at a low speed integrally with the rotating body (hub), a plurality of spheres stored in the sphere storing recesses of the rotating body are stored in the sphere storing recesses. When the polygon mirror is rotated at a high speed integrally with the rotating body (hub) while being constrained by the spherical body constraining portion formed over a predetermined angle range on the circumferential side, a plurality of the housings accommodated in the spherical body recesses of the rotating body are provided. By moving the sphere to the outer peripheral side in the concave portion for storing the sphere by centrifugal force, the imbalance due to the eccentricity of the polygon mirror can be corrected automatically and satisfactorily.

1 is an overall configuration diagram showing a disk drive device according to the present invention. It is a figure for demonstrating the spindle motor of Example 1 which concerns on this invention, (a) is a longitudinal cross-sectional view, (b) is a XX arrow directional view in (a). In the spindle motor of Example 1 which concerns on this invention, it is the figure which showed typically the state with which the turntable was inclined and fixed with respect to the motor shaft, (a) is a longitudinal cross-sectional view, (b) is (a) ) In FIG. (A), (b) is the figure which showed typically the state in which the turntable fixed to the one end side of the motor shaft of the spindle motor of Example 1 which concerns on this invention rotates at low speed. It is a figure for demonstrating the spindle motor of Example 2 which concerns on this invention, (a) is a longitudinal cross-sectional view, (b) is a XX arrow directional view in (a). In the spindle motor of Example 2 concerning the present invention, it is a figure showing typically the state where the turntable was inclined and fixed to the motor axis, (a) is a longitudinal section and (b) is (a) ) In FIG. It is a figure for demonstrating the spindle motor of Example 3 which concerns on this invention, (a) is a longitudinal cross-sectional view, (b) is a XX arrow directional view in (a). In the spindle motor of Example 3 which concerns on this invention, it is the figure which showed typically the state with which the turntable was inclined and fixed with respect to the motor shaft, (a) is a longitudinal cross-sectional view, (b) is (a) ) In FIG. It is a figure for demonstrating the conventional automatic balancing apparatus and a motor using the same, (a) is a longitudinal cross-sectional view, (b) is a XX arrow line view in (a).

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Disk drive device, 2 ... Housing, 3 ... Screw, 4 ... Optical pick-up,
10A: Spindle motor of Example 1,
10B ... Spindle motor of Example 2,
10C: spindle motor of Example 3,
DESCRIPTION OF SYMBOLS 11 ... Motor base, 12 ... Bearing holder, 13 ... Cap, 14 ... Screw,
15 ... Bearing (sintered oil-impregnated bearing), 16 ... Thrust plate,
17 ... Stator core, 18 ... Coil for motor drive,
21 ... Motor shaft, 22 ... Rotor yoke, 22a ... Disk-shaped upper surface part, 22b ... Cup part,
23 ... An annular magnet for driving the motor, 24 ... A retaining ring for preventing the shaft from coming off,
30... Unbalance correction mechanism that is a main part of the first embodiment.
31 ... Turntable (rotary body),
31a: Disc mounting surface (one surface as a height measuring surface),
31b ... center hole fitting part, 31c ... annular convex part, 31d ... concave part for magnet storage,
31e: recess for storing magnetic sphere, 31e1: outer peripheral wall,
32 ... Annular magnet, 32a ... Magnetic sphere restraint part, 32b ... Non-magnetic sphere restraint part,
33 ... balance sphere (magnetic sphere), 34 ... ring-shaped rubber plate,
40... Unbalance correction mechanism that is a main part of the second embodiment.
41 ... turntable (rotary body),
41a: Disc mounting surface (one surface as a height measuring surface),
41b ... center hole fitting portion, 41c ... annular convex portion, 41d ... steel ball housing concave portion,
41d1 ... outer peripheral wall,
42 ... steel ball rolling member, 42a ... annular convex part, 42b ... conical surface,
42b1 ... steel ball restraint part, 42b2 ... non-steel ball restraint part,
43 ... balance sphere (steel sphere), 44 ... ring-shaped rubber plate,
50... Unbalance correction mechanism that is a main part of the third embodiment.
51. Turntable (rotary body),
51a: Disc mounting surface (one surface as a height measuring surface),
51b ... center hole fitting part, 51c ... annular convex part, 51d ... steel ball storage concave part,
51d1 ... outer peripheral wall,
52 ... Steel ball rolling member, 52a ... An annular convex part, 52b ... Conical surface,
52b1 ... steel ball restraint part,
53 ... Balance sphere (steel sphere), 54 ... Ring-shaped rubber plate,
D: Disc, K: Virtual line, R: Rotor, S: Stator,
δ ... An angle formed between one surface of the rotating body and one end side of the motor shaft.

Claims (6)

It is fixed to one end side of a motor shaft that is rotationally driven from a first rotational speed to a second rotational speed that is higher than the first rotational speed, and has a spherical housing recess coaxial with the motor shaft. A rotating body formed in a substantially annular shape,
The sphere storage recess is movably stored, and when the rotator is rotated at the first rotational speed, the rotator is constrained to the inner periphery of the sphere storage recess. In a spindle motor comprising an unbalance correction mechanism portion comprising a plurality of balance spheres that move to the outer peripheral side in the sphere storage recess when rotated at the second rotational speed,
The concave portion for storing the spherical body has a spherical body constraining portion for constraining the plurality of balance spheres within a predetermined angular range along the inner circumference when the rotating body is rotated at the first rotational speed. And when one surface of the rotating body is used as a height measuring surface for measuring the height of the rotating body corresponding to the inclination of the rotating body with respect to the motor shaft, The spherical body restraining portion is set to a position where a virtual line orthogonal to the motor shaft is in contact with a portion having the highest height in the one surface. Fixed to one end of a motor shaft that is rotationally driven from a first rotational speed to a second rotational speed that is higher than the first rotational speed, and a spherical housing recess is coaxial with the motor shaft. A rotating body formed in a substantially annular shape,
The sphere storage recess is movably stored, and when the rotator is rotated at the first rotation speed, the rotator is constrained to the inner peripheral side of the sphere storage recess. In a spindle motor comprising an unbalance correction mechanism portion composed of a plurality of balance spheres that move to the outer peripheral side in the sphere storage recess when rotated at the second rotational speed,
The concave portion for storing the spherical body has a spherical body constraining portion for constraining the plurality of balancing spheres when the rotating body is rotated at the first rotational speed within a predetermined angular range along the inner circumference. The spherical body restraining portion is formed so as to include a circumferential position where an angle formed between one surface of the rotating body and the one end side of the motor shaft is the smallest. Spindle motor.   The balance sphere is formed of a magnetic sphere, and the sphere restraining portion is configured to fix an annular magnet magnetized only over the predetermined angle range to an inner peripheral side in the sphere housing recess. The spindle motor according to claim 1 or 2.   The balance sphere is formed of a steel sphere, and the concave portion for storing the sphere is formed in a conical surface whose inner bottom surface decreases from the outer peripheral side toward the inner peripheral side, and on the inner peripheral side of the conical surface. The spherical body constraining part is formed by being dented in a pocket shape over the predetermined angle range with respect to a convex surface formed by projecting upward the circumference other than the spherical body constraining part. Item 3. The spindle motor according to Item 2.   The balance sphere is formed of a steel sphere, and the concave portion for storing the sphere is formed in a conical surface whose inner bottom surface decreases from the outer peripheral side toward the inner peripheral side, and on the inner peripheral side of the conical surface. 3. The spindle motor according to claim 1, wherein the spherical body restraining portion is formed in a triangular concave groove shape over the predetermined angle range. A disk drive device for driving a disk mounted on the rotating body, wherein the spindle motor according to any one of claims 1 to 5 is mounted in a housing and fixed to one end side of the motor shaft. There,
When the disk is rotated at the first rotational speed integrally with the rotating body, the plurality of balance spheres stored in the spherical body storing recesses are set at a predetermined angle toward the inner peripheral side of the spherical body storing recesses. The plurality of balance spheres stored in the sphere storage recesses when the disk is rotated at the second rotational speed integrally with the rotating body while being restrained by the sphere restraining portion formed over a range. Is moved to the outer peripheral side in the concave portion for accommodating the spherical body by centrifugal force to correct the unbalance due to the eccentricity of the disc.

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