JPH10309057A - Rotation driving mechanism - Google Patents

Abstract

PROBLEM TO BE SOLVED: To see that the rotation performed by a rotation driving means is performed in condition that it does not cause the eccentricity of the rotation center. SOLUTION: This rotation driving mechanism is equipped with a rotating member 11 which is rotated through a pivot by a rotation driving means 3, and a plurality of balance members 20, 20,... which are arranged on the opposite side in axial direction across a rotated body 1 being installed on the rotating member 11 and being driven together with the rotating member and also can shift within the specified range. These balance members are rotated at the time of rotation of the rotating member 11 and also shift to the pivot 10, and the center of gravity (composite center of gravity) of the composite rotator composed of the rotating member, the rotating member included in the rotational driving member, the balance members, and the rotated member is positioned above the axis of rotation.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a rotary drive mechanism. More specifically, the present invention relates to a technique for preventing rotation of a spindle during rotation by causing rotation performed by a rotation driving unit to be performed without causing eccentricity of a rotation center.

[0002]

2. Description of the Related Art For example, in a disk drive device for reproducing or recording data on a recording disk such as an optical disk or a magneto-optical disk mounted on a disk table as a rotating object provided in a computer, the recording disk is rotated by a rotation driving mechanism. ing. This rotary drive mechanism has a spindle motor serving as a rotary drive means and a disk table fixed to the tip end of a spindle shaft of the spindle motor. The disk is rotated with the rotation of the disk table. And
Recording and / or reproduction of information signals is performed on the recording disk rotated by such a rotation drive mechanism by an optical pickup or a magnetic head device.

[0003]

Incidentally, a recording disc such as the above-mentioned optical disc may have a weight imbalance at the time of manufacture or the like. When a recording disk having such a weight imbalance is rotated by the rotation drive mechanism, the recording disk vibrates together with the disk table because the center of rotation does not coincide with the center of gravity. Due to this vibration, focusing and tracking on the signal recording surface of the recording disk by the optical pickup device and tracking of the recording track of the recording disk by the magnetic head device cannot be performed well.

[0004] In general, the amount of imbalance that occurs on a recording disk varies depending on the recording disk.

Furthermore, recently, it has become possible to record or reproduce data on or from a recording disk at a high speed, and there is a problem that the vibration of the recording disk increases as the rotation speed increases.

Therefore, the vibration of the recording disk cannot be suppressed unless there is a vibration suppressing means capable of coping with the weight imbalance amount or the rotation speed for each recording disk.

Therefore, an object of the present invention is to overcome the above-mentioned problems and to make the rotation performed by the rotation driving means be performed without causing eccentricity of the rotation center.

[0008]

According to the present invention, there is provided a rotary drive mechanism comprising:
In order to solve the above-described problem, a rotating member that is rotated via a support shaft by a rotation driving unit, and a rotating member mounted on the rotating member and rotated together with the rotating member, on the opposite side in the axial direction with respect to the rotating member. And a plurality of balance members that are positioned and movable within a predetermined range with respect to the support shaft.

Therefore, in the rotary drive mechanism of the present invention,
A composite rotator including a rotation member, a rotation member, a rotation member, a balance member, and a rotated member included in the rotation member and the rotation driving unit, wherein the balance member rotates with the rotation of the rotation member and moves with respect to the rotation member. (Combined center of gravity) is positioned on the rotation axis.

[0010]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of a rotary drive mechanism according to an embodiment of the present invention. In the embodiments described below, the present invention is applied to a rotary drive mechanism in a disk drive device that performs reproduction and recording on a recording disk such as an optical disk or a magneto-optical disk.

A recording disk 1 to be mounted on a disk table, which will be described later, as a rotatable member is formed by forming a signal recording surface on a transparent substrate formed of a disc having a diameter of 120 mm from a synthetic resin material such as polycarbonate. ing. The recording disk 1 has a circular opening (chucking hole) 1a at the center thereof. The recording disk 1 is positioned by fitting the positioning protrusion of the disk table into the circular opening 1a.

The disk drive device 2 includes a mechanical chassis 5 on which a spindle motor 3 and an optical pickup device 4 serving as rotation driving means are mounted, and a plurality of dampers 6 for floatingly supporting the mechanical chassis 5 with respect to a base chassis (not shown). .. (See FIG. 1).

The optical pickup device 4 is supported by the mechanical chassis 5 via guide shafts 7, 7 so as to be movable in the radial direction of the recording disk 1 mounted on the disk table. The optical pickup device 4 has a light source (not shown) such as a laser diode and a photodetector, and irradiates the recording disk 1 with a laser beam emitted from the light source via the objective lens 8. It is configured to detect the reflected light from the light detector by a photodetector.

The rotation drive mechanism 9 includes a disk table (turntable) 11 fixed to an upper end of a spindle (spindle shaft) 10 rotated by the spindle motor 3 and a chucking member to be described later. (See FIG. 3).

The support shaft 10 is rotatably supported on a motor board 13 fixed on the mechanical chassis 5 via rotation bearings 14 and 14 around the shaft. A motor rotor 15 constituting the spindle motor 3 is attached to the support shaft 10, and the motor rotor 15 is formed in a substantially cylindrical shape, and a drive magnet 16 is fixed to an inner surface thereof. The drive magnet 16 faces the stator coil 17 fixed on the motor board 13.

Thus, in the spindle motor 3,
When a drive current is supplied to the stator coil 17, a magnetic field generated by the stator coil 17 acts on the drive magnet 16, and the drive magnet 16 and the motor rotor 15 rotate together with the support shaft 10, thereby causing the disk table 11 to rotate. Rotated. That is, the support shaft 10 is a drive shaft of the spindle motor 3.

The disk table 11 serving as a rotating member is formed of a non-magnetic material, and has a moving space 12 formed therein. The disk table 11 includes a storage portion 18 and a top plate portion 1 that covers the storage portion 18 and on which the recording disk 1 is mounted.
9 and is fixed to the support shaft 10 by press-fitting the upper end of the support shaft 10 into a support shaft press-fitting hole formed in the center of the housing portion 18.

The housing portion 18 comprises an annular bottom wall 18a, an outer peripheral wall 18b erected from the outer peripheral edge of the bottom wall 18a, and an inner peripheral wall 18c erected from the inner peripheral edge of the bottom wall 18a. The height of the wall 18b is equal to the height of the inner peripheral wall 18c.

The top plate 19 comprises a thin, substantially annular disk holding portion 19a and a positioning projection 19b projecting upward from the center thereof and having a truncated cone shape. Positioning protrusion 1
9b is for positioning the recording disk 1 by fitting it into the circular opening 1a of the recording disk 1, and
A magnet 19c is built in the positioning projection 19b.

The top plate 19 covers the opening surface of the accommodating portion 18 to form an annular moving space 12 inside the disk table 11.

In the moving space 12, for example, six balance balls 20, 20,... Serving as balance members are accommodated. Are formed in a spherical shape from a magnetic material such as iron or nickel. Each of the balance balls 20, 20,... The surface 21 can be moved in the radial direction up to a position where it comes into contact with the surface 21 and in the circumferential direction around the support shaft 10. That is, each balance ball 20,
Are restricted by the outer inner peripheral surface 21 into an area within a certain distance from the rotation axis of the support shaft 10. Are prevented from moving in the axial direction of the support shaft 10 by the bottom wall 18a of the storage portion 18 of the disc table 11 and the top plate portion 19, respectively. The diameter of each of the balance balls 20, 20,... Is slightly smaller than the distance between the upper surface of the bottom wall 18a and the lower surface of the top plate 19.

A magnet (permanent magnet) 22 serving as a magnetic field generating means is provided at the center of the moving space 12. The magnet 22 is formed in an annular shape and
8 is provided on the inner peripheral wall 18c so as to be fitted outside,
Are arranged coaxially with respect to. As shown in FIG. 3, the magnet 22 is magnetized in two poles in a direction perpendicular to the main surface, that is, the front and rear surfaces are magnetic poles. Also, when the support shaft 10 is stopped, the magnet 22 attracts the balance balls 20, 20,... In the moving space 12 regardless of the direction of the support shaft 10, and contacts the outer peripheral portion thereof. To hold. That is, the magnet 22
Generate magnetic force enough to vertically pull up the balance spheres 20, 20,... Located in contact with the outer inner peripheral surface 21 of the housing portion 18 and to attract the balance spheres 20 to the outer peripheral portion thereof.

Each balance sphere 20, 2 in the moving space 12
0,... Indicate that the magnetic flux emitted from the magnet 22 passes through the balance spheres 20, 20,. Become. That is, as shown in FIG. 2, the angle の around the central axis of the support shaft 10 between the balance spheres 20, 20,.
1 to $ 6 are equal to each other.

The chucking member 23 is formed as a rotating member which is rotated by the rotation of the spindle motor 3 in the same manner as the disk table 11.
1 and is rotatably supported by a support member (not shown). The chucking member 23 is formed of a non-magnetic material, and has a moving space 24 formed therein. Then, the chucking member 23 includes the housing portion 25 and the housing portion 25.
And a top plate 26 covering the top plate.

The receiving portion 25 has a substantially disk-shaped bottom wall 25a.
And an outer peripheral wall 25b erected from the outer peripheral edge of the bottom wall 25a
And a protruding portion 25c erected from the center of the bottom wall 25a, and the outer peripheral wall 25b and the protruding portion 25c have the same height. A fitting projection 25d is vertically provided from the center of the bottom wall 25a. The fitting projection 25d is formed at the center of the top plate 19 of the disk table 11 when the recording disk 1 is chucked. Into the fitting hole. An annular magnetic metal body 27 is provided on the lower surface of the bottom wall 25a so as to be externally fitted to the fitting projection 25d.

The top plate 26 is formed in a thin disk shape.
The annular moving space 24 is formed inside the chucking member 23 by covering the opening surface of the housing portion 25 with 6.
The moving space 24 is formed in the same size and shape as the moving space 12 described above, and has therein the balancing sphere 2.
The balance spheres 28, 28,... Having the same size, shape, and material as 0, 20,... And the magnet 29 having the same size, shape, and magnetic force as the magnet 22 are provided in the moving space 12 of the disk table 11. They are arranged similarly.
The balance spheres 28, 28,...
In the same manner as 0, 20,..., In the movement space 24, it is possible to move in the radial direction and the circumferential direction up to a position where it comes into contact with the inner surface (outer inner peripheral surface) 30 of the outer peripheral wall 25 b of the storage portion 25. When it is not rotating, it is located at equal intervals on the outer peripheral portion of the magnet 29.

Thus, the recording disk 1 has the circular opening 1.
In the state where the positioning projection 19b of the disk table 11 is fitted and positioned at a, the magnet 19c built in the positioning projection 19b attracts the magnetic metal body 27 of the chucking member 23, and the disk table 11 It is reliably held and chucked by being sandwiched between the chucking member 25.

When the drive current is supplied to the stator coil 17 of the spindle motor 3 and the motor rotor 15 is rotated while the recording disk 1 is chucked as described above, the spindle 10 and the disk table 11 are rotated together with the motor rotor 15. , The chucking member 23 and the chucked recording disk 1 are integrally rotated, and the balance spheres 20, 20,.
Are rotated around the rotation axis of the support shaft 10 in the moving space 12 and the moving space 24, respectively. That is, these motor rotor 15, support shaft 10, disk table 11,
Chucking member 15, recording disk 1, balance ball 2
.. And the balance spheres 28, 28,... Constitute a combined rotator (hereinafter, the center of gravity of the whole of these members, that is, the center of gravity of the combined rotator is referred to as “combined center of gravity”). ).

When the rotation speed of the recording disk 1 reaches the used rotation range by the rotation of the spindle motor 3, the balance balls 20, 20,... Move by centrifugal force as shown in FIGS. Reach a position where they contact the outer inner peripheral surface (the inner surface of the outer peripheral wall 18b) 21 of the space 12, and the balance spheres 28, 28,. 25b inner surface) 30
Has reached the position where it abuts. When the recording disk 1 is rotated, the balance spheres 20, 20,... Arranged in the movement space 12 of the disk table 11 and the balance spheres 28 arranged in the movement space 24 of the chucking member 23, .. Perform the same movement (movement) as in FIG. 28,.
Balance spheres 20, 20,... Arranged in the moving space 12
Only those relating to .. are shown (see FIGS. 4 to 6).

As described above, the balance balls 20, 20,...
22 is in contact with outer inner peripheral surface 21
Are attracted to the balance spheres 20, 20,... By the magnetic force of the balance spheres 20, 20,.
, 28,... Are in contact with the outer inner peripheral surface 30, the balance sphere 28 by the magnetic force generated by the magnet 29,
The suction force on the balance balls 28, 28,.
Are smaller than the centrifugal force acting on.

If the recording disk 1 to be rotated has no weight imbalance (eccentricity), or if the recording disk 1 is not mounted on the disk table 11, the balance balls 20, 20,.・ (Balance ball 2
, 8) are located at equal angular intervals around the rotation axis of the support shaft 10, as shown in FIG.

The recording disk 1 may have a weight imbalance during manufacturing. Here, the term “unbalance” means that the center of gravity of the recording disk 1 is not located at the center of the recording disk 1. For example, the unbalance means that the substrate thickness of the recording disk 1 is uneven or the density is uneven. Occurs when

When the recording disk 1 having such an imbalance is rotated together with the disk table 11, the spindle motor 3 and the like rotating the recording disk 1 vibrate including the mechanical chassis 5. When the recording disk 1 having such a weight imbalance is mounted on the disk table 11 and rotated, the balance balls 20, 20,... (Balance balls 28, 28,. 6), as shown in FIG. 6, the moving space 12 is located at a position where the imbalance is canceled according to the direction of the imbalance and the amount of the imbalance.
It moves within the (moving space 24). That is, the balance spheres 20, 20,... (Balance spheres 28, 28,.
()) Even if the disc table 11 (chucking member 23) is rotated, the disc table 11 (chucking member 23) rotates separately from the disc table 11 (chucking member 23). Then, the disk table 11 (the chucking member 23) rotates relatively with the disk table 11 (the chucking member 23). Each of the balance balls 20, 20,... (Balance balls 28, 28,...
()) Gradually moves to a position facing the recording disk 1 in the unbalance direction.

The balance spheres 20, 20,... And the balance spheres 20, 20,... (Balance spheres 28, 28,. 6), as shown in FIG. 6, the position of the angle + θn with respect to the direction of the unbalance (that is, the direction in which the center of gravity of the recording disk 1 exists when viewed from the rotation center of the support shaft 10) is more than the position of the unbalance. Are arranged at equal intervals in the range up to the position of the angle −θn through the opposite side of the direction (that is, in the range of the angle ± θn with respect to the unbalanced direction, the balance spheres 20, 20,. ...
(The balance balls 28, 28,...) Do not exist. ).

At this time, each balance ball 20, 20,.
・ (Balance spheres 28, 28, ...)
It is a position facing the unbalance direction via the center of rotation, and is located on the facing line.

Thus, each of the balance balls 20, 20,.
When the recording disk 1 having an unbalance is rotated, the balance spheres 28, 28,... Are automatically moved by a so-called self-aligning action, so that the position of the combined center of gravity is on the rotation axis. Located in. Therefore, the composite rotating body rotates without vibrating, and the unbalanced recording disk 1 can be rotated with its center of gravity positioned on the rotation axis.

Such a self-aligning action is achieved by adjusting the rotational frequency of the composite rotator to the resonance frequency of the dampers 6, 6,... (The plane perpendicular to the rotational axis of the composite rotator (x, y plane in FIG. 1). This occurs effectively when the resonance frequency is higher than the resonance frequency in the direction in parentheses). In other words, a recording disk on which information signals are recorded or reproduced at a high speed can be generated effectively.

In the above-described rotary drive mechanism 9,
Since the balance spheres 20, 20,... And the balance spheres 28, 28,... Are arranged at equal angular intervals when the disc table 11 and the chucking member 23 are stopped, the disc table 11 and the chucking member At the start of the rotation of 23, each balance ball 20, 2
.. Or the balance spheres 28, 28,.

Therefore, as described above, the balance ball 20,
And the rotating drive mechanism 9 provided with the balance balls 28, 28,..., No vibration occurs in the composite rotating body even when the recording disk 1 having a weight imbalance is rotated. That is, in the disk drive device 2, the recording disk 1 having a weight imbalance
The information signal can be written or read satisfactorily on the signal recording surface.

When the recording disk 1 is rotated in this manner, the optical pickup device 4 irradiates the recording disk 1 with a laser beam and receives and detects the reflected light. The optical pickup device 4 is moved along the guide shafts 7, 7, so that the optical pickup device 4 is moved away from the support shaft 10, that is,
The recording disk 1 is moved in the radial direction of the recording disk 1 mounted on the disk table 11, and is moved over the inner and outer circumferences of the recording disk 1. Then, by the optical pickup device 4,
Writing or reading of an information signal to / from the recording disk 1 is performed.

In the rotary drive mechanism 9, when the spindle motor 3 is started, that is, when the disk table 1 is turned on.
When the rotation of the chucking member 1 and the chucking member 23 is started from the stopped state, the balance balls 20, 20,.
, And the balance balls 28, 28,... Do not relatively move with respect to the disk table 11 and the chucking member 23, and the effect of the self-centering action can be promptly obtained if the balance balls 28, 28,. That is, as shown in FIG.
The rotation speed of the disc table 11 (the chucking member 23) and the balance balls 20, 20,.
The rotation speed of the disk table 11 (chucking member 23) is at least the rotation speed in use (rotation frequency equal to or higher than the resonance frequency of the dampers 6, 6, ...). When it reaches, it is desirable that it be 0.

Therefore, in the rotation drive mechanism 9 described above, the magnet 22 is placed in the moving space 12 (moving space 24).
(Magnet 29), and balance spheres 20, 20,... (Balance spheres 28, 28,...) Against centrifugal force during rotation of the disc table 11 (chucking member 23).
.) Are attracted to the magnet 22 (magnet 29), and the balance spheres 20, 20,...
, ...) to transmit the starting torque to the balance ball 20,
(Balance balls 28, 28,...) Are rotated by following the disk table 11 (the chucking member 23).

Therefore, when the disc table 11 (chucking member 23) is rotated, the balance balls 20, 2
(Balance spheres 28, 28,...) Are attracted for a long time, and the balance spheres 20, 20,.
2 (magnet 29), the rotation of the disk table 11 (chucking member 23) is likely to be performed in synchronization with the rotation of the disk table 11 (chucking member 23), and the effect of the self-centering action can be obtained quickly.

Also, after the balance spheres 20, 20,... (Balance spheres 28, 28,...) Are separated from the magnet 22 (magnet 29) by centrifugal force, the centering action is performed quickly. , The balance spheres 20, 20,... (Balance spheres 28, 28,.
·) Disk table 11 (chucking member 23)
Must be made without any resistance. That is, the balance balls 20, 2
(Balance spheres 2, 20,...) With the rotation of the balance spheres 28, 28,.
, 8) and the disc table 11 (the chucking member 23) should preferably have a small frictional force.

Therefore, in the rotation drive mechanism 9 described above, the balance sphere 20, which is a spherical body, is used as the balance member.
(Balance spheres 28, 28,...) And balance spheres 20, 20,.
,..) And the inner surface of the disk table 11 (the chucking member 23).

Therefore, the balance balls 20, 20,...
(Balance balls 28, 28,...) Are magnets 22
After leaving the (magnet 29), the balance ball 20,
The balance rotation of the balance balls 20,... With respect to the disk table 11 (the chucking member 23) is performed in a state where the resistance is small, and the centering action is quickly performed.

As described above, in the rotary drive mechanism 9, the balance balls 20, 20,... Are arranged in the moving space 12 of the disk table 11, and the moving space 24 of the chucking member 23 is Balance ball 28, 28, ...
Are arranged so that the combined center of gravity of the combined rotating body is positioned on the rotation axis during rotation of the recording disk 1 by both of these automatic alignment mechanisms.

This is because, as shown in FIG. 10, the self-aligning mechanism is provided on one side, that is, only on the upper side or the lower side of the chucked recording disk 1 (FIG. 10 shows the case where the self-aligning mechanism is provided only on the lower side). Is shown on the recording disk 1.
The direction of the force F1 acting on the rotating shaft (indicated by the one-dot chain line in FIG. 10) due to the imbalance of the force F2 is opposite to the direction of the force F2 caused by the self-centering mechanism that attempts to eliminate the force. This is because, because the heights of the points of action of these forces are different, a force that tilts the support shaft 10 acts (this state is indicated by a two-dot chain line), and this is to be prevented.

That is, in the above-described rotary drive mechanism 9, the self-centering mechanism having the balance balls 20, 20,... On the opposite side of the unbalanced recording disk 1 and the balance balls 28, 28 ,..., The direction of the force F1 acting on the rotating shaft (indicated by the one-dot chain line in FIG. 8) due to the imbalance of the recording disk 1 and canceling the direction. Even if the directions of the forces F3 and F4 caused by the self-centering mechanism are opposite to each other, the points of action of the forces F3 and F4 that attempt to eliminate the forces above and below the point of action of the force F1 caused by the imbalance Therefore, it is possible to prevent the force for tilting the support shaft 10 from acting on the support shaft 10.

In order to completely prevent the support shaft 10 from being tilted, it is desirable to make the distances between the two self-aligning mechanisms to the chucked recording disk 1 equal.

The disk table 11 and the chucking member 23 have a certain thickness in order to provide the magnet 19c and the magnetic metal body 27 attracted to the magnet 19c and to maintain a certain rigidity that can withstand rotation. ing.

Here, as described above, the rotary drive mechanism 9 has two self-aligning mechanisms, that is, the disk table 11.
, And a self-aligning mechanism having balance balls 28, 28,... Disposed in the chucking member 23. F3, F4 due to two self-aligning mechanisms
Since the resultant force is balanced with the force F1 caused by the unbalance amount to eliminate the imbalance (see FIG. 8), only one self-aligning mechanism, for example, the disk table 11 (the chucking member 23) is used. In comparison with the case where the force F2 caused by the self-centering mechanism is balanced with the force F1 caused by the amount of unbalance to try to eliminate the imbalance (see FIG. 10), The balance balls 20, 20,... And the balance balls 28, 28,.

Therefore, in the rotation drive mechanism 9, the disc table 11 and the chucking member 23 have the disc table 11 within the above-mentioned original thickness range.
The self-aligning mechanism can be provided in each of the chucking member 23 and the chucking member 23. By providing the self-aligning mechanism, the disk table 11 and the chucking member 23 do not become large.

The arrangement of the balance spheres 20, 20,... And the balance spheres 28, 28,... On the disk table 11 and the chucking member 23 has been described above. Alternatively, a case body may be provided as a rotating member in the rotation drive mechanism 9, and a moving space in which the balance sphere is arranged may be formed in the case body instead of the disk table 11, and the balance sphere may be arranged (see FIG. 9).

The case body 31 is formed of a non-magnetic material and has an annular shape, and is fixed to the support shaft 10 inserted into the center hole at a position between the disk table 11 and the motor rotor 15. The case body 31 includes the housing portion 32 and the housing portion 3.
The housing portion 32 is formed from an annular bottom wall 32a, an outer peripheral wall 32b rising from the outer peripheral edge of the bottom wall 32a, and an inner peripheral edge of the bottom wall 32a. An outer peripheral wall 32b and an inner peripheral wall 32
The height of c is the same.

The top plate 33 has a thin annular shape,
An annular moving space 34 is formed inside the case body 31 by covering the opening surface of the second case 2.

In the moving space 34, the balance spheres 20, 2
Are housed in the moving space 34, and the magnet 22 is disposed on the inner peripheral wall 32c so as to be externally fitted.

Thus, even in the case where the case body 31 is provided and the moving sphere 34 is formed in the case body 31 and the balance spheres 20, 20,... When the disc 1 is rotated, the balance spheres 20, 20,... And the balance spheres 28, 28,. Move and position the composite center of gravity of the composite rotator on the rotation axis.

Therefore, the composite rotating body rotates without vibrating, and in the disk drive device 2, the information signal can be written or read satisfactorily on the signal recording surface of the recording disk 1 having a weight imbalance. .

It is to be noted that, instead of arranging the balance sphere in the chucking member 23 and the case body 31 provided on the disc table 11 side, the case body 31 is provided above the chucking member 23 and the inside of the case body 31 is provided. The balance sphere may be arranged between the disk and the disk table 11.

Further, the case table 3 and the chucking member 23 do not form a moving space,
1 and 31 are provided below the disc table 11 and above the chucking member 23, respectively.
You may make it arrange | position a balance ball in 1,31.

In the above-described embodiment, the self-aligning mechanism using the balance sphere as the balance member has been described. However, the present invention is not limited to this. It includes all the self-aligning mechanisms described in the specification of Japanese Patent Application No. 53704 filed on March 7, 1997.

In the above-described embodiment, the rotary drive mechanism according to the present invention is applied to the rotary drive mechanism of a disk drive device. However, the rotary drive mechanism according to the present invention is applied to an industrial machine or the like. The present invention can also be applied to those provided in other appliances.

[0064]

As is apparent from the above description, in the rotary drive mechanism of the present invention, a rotary member rotated via a spindle by the rotary drive means, and a rotary member mounted on the rotary member. A plurality of balance members that are located on the opposite side in the axial direction with the rotated body rotated therewith and are movable within a predetermined range with respect to the support shaft,
The balance member is rotated at the time of rotation of the rotation member and moves with respect to the support shaft. The rotation member includes a rotating member, a balance member, and a rotating member included in the rotation driving unit. Since the center of gravity (combined center of gravity) is located on the rotation axis, the combined rotator can be rotated without generating vibration, and the rotation is performed without causing eccentricity of the center of rotation. Because the balance member is located on the opposite side in the axial direction across the body,
It is possible to prevent the force for tilting the support shaft from acting on the support shaft, and it is possible to dispose the balance member within the range of the size originally possessed by the rotating member. As a result, the size of the composite rotating body does not increase.

According to the second aspect of the present invention, a moving space in which the cross-sectional shape in a direction perpendicular to the axial direction is annular and a balance member is arranged is formed inside the rotating member. A magnet is provided in the center of the
The balance member is formed as a spherical body made of a magnetic material. When the rotating member is not rotating, the spherical body is adsorbed on the outer periphery of the magnet, and when the rotating member rotates, the spherical body is separated from the outer periphery of the magnet by centrifugal force. As a result, when the rotating member starts rotating from the stopped state, the starting torque is transmitted from the rotating member, the balance member follows the rotating member and starts rotating with the balance member, and the self-centering action is quickly performed. Is executed.

It should be noted that the specific shapes and structures of the respective parts shown in the above-described embodiments are merely examples of the embodiment when practicing the present invention.
These should not be construed as limiting the technical scope of the present invention.

[Brief description of the drawings]

FIG. 1 shows an embodiment of the rotary drive mechanism of the present invention together with FIGS. 2 to 7, and is a schematic perspective view showing a disk drive device provided with the rotary drive mechanism.

FIG. 2 is an enlarged horizontal sectional view showing a disk table.

FIG. 3 is an enlarged vertical sectional view showing a combined rotating body.

FIG. 4 is an enlarged horizontal sectional view showing a state where the disk table is rotated.

FIG. 5 is an enlarged vertical sectional view showing a state in which the disk table is rotated.

FIG. 6 is an enlarged horizontal sectional view of the disc table showing a state where the self-centering action has been performed;

FIG. 7 is a graph showing changes in rotation speeds of a rotating member (a disc table or a chucking member) and a balance member in the rotation driving mechanism.

FIG. 8 is a conceptual diagram showing a force acting on a rotating shaft when an alignment operation is performed.

FIG. 9 is an enlarged vertical sectional view showing another embodiment of the rotation drive mechanism.

FIG. 10 is a conceptual diagram showing a force acting on a rotating shaft when one self-aligning mechanism is provided in the rotation driving mechanism.

[Description of Signs] 1 ... Recording disk (rotated body), 3 ... Spindle motor (rotation driving means), 9 ... Rotation driving mechanism, 10 ... Support shaft,
1 disk table (rotating member), 12 moving space,
Reference numeral 20: balance ball (balance member), 22: magnet, 23: chucking member (rotary member), 24: moving space, 28: balance ball (balance member), 29: magnet, 31: case body (rotary member), 34 ... Moving space

Claims (2)

[Claims] A rotating member rotated by a rotation driving means via a support shaft; and a rotating member mounted on the rotating member and positioned on an opposite side in an axial direction with a rotating body interposed therebetween and rotated together with the rotating member. A plurality of balance members movable within a predetermined range with respect to the support shaft, wherein the balance member is rotated when the rotation member rotates and moves with respect to the support shaft, and A rotation driving mechanism, wherein a center of gravity (synthetic center of gravity) of a combined rotating body including a rotating member, a balance member, and a rotated body is located on a rotation axis. 2. A moving space in which a cross section in a direction perpendicular to the axial direction is annular and a moving space in which the balance member is arranged is formed inside the rotating member, and a magnet is provided at a center portion of the moving space. The balance member is formed as a spherical body made of a magnetic material. When the rotating member is not rotating, the spherical body is adsorbed on the outer periphery of the magnet, and when the rotating member is rotating, the spherical body is separated from the outer periphery of the magnet by centrifugal force. The rotation drive mechanism according to claim 1, wherein the rotation drive mechanism is separated from the section.