JPH10281227A - Self-aligning device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make noise small and quiet and to provide high precision self- aligning by arranging a plural number of balance weights so as to freely roll in an annular cavity of a disk type case with a rotary shaft as its center and providing a damping material with a circular arc groove applied on it on an outer peripheral wall of this annular cavity. SOLUTION: A rotary shaft 1 of a motor is installed on a stator 2 free to rotate through a bearing 6, a cylindrical rotor yoke 4 to cover an exciting coil 3 is fixed on this stator 2, and a specifically magnetized magnet 5 is fixed against an outer peripheral surface of this exciting coil 3 on a circumferential surface of this rotor yoke 4. A disk type case 8 made of a disk type non- magnetic material having an annular cavity 8a is fixed on the rotary shaft 1, a ring magnet 9 having specified attraction force is provided on an inner peripheral side of the annular cavity 8a, a balance weight 10 is attracted to the magnet 9 at the time when the number of rotation of the rotary shaft 1 is low, and it is pressurized in a circular arc shape of a damping material 11 of the annular cavity 8a and stabilized when the number of rotation is high.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an automatic alignment device suitable for use in, for example, an optical disk player.

[0002]

2. Description of the Related Art Generally, an optical disc may have a weight imbalance at the time of manufacture or the like. When an optical disk having a weight imbalance is rotated, the optical disk vibrates together with the turntable attached to the end of the rotating shaft of the motor. In this case, the optical pickup cannot perform appropriate focusing on the signal recording surface of the optical disc.

[0003] Furthermore, the amount of imbalance that occurs in an optical disk is not always a fixed value. Recently, data can be recorded or reproduced on the optical disk at high speed. However, if the number of rotations is increased, the vibration increases even if the amount of unbalance is constant.

Conventionally, an automatic alignment device as shown in FIG. 6 has been proposed as a device for suppressing the vibration caused by the weight imbalance of the optical disk.

In FIGS. 6A and 6B, reference numeral 1 denotes a rotating shaft of a motor, and a turntable on which, for example, an optical disk is mounted is attached to an end of the rotating shaft 1.

Reference numeral 2 denotes a stator in which the rotating shaft 1 is rotatably mounted via a bearing 6, and the exciting coil 3 is provided on the stator 2 so as to be fixed. Also, this rotating shaft 1
In addition, a cylindrical rotor yoke 4 is fixed so as to cover the exciting coil 3, and a magnet 5 having a predetermined magnetization is fixed to the inner peripheral surface of the rotor yoke 4 so as to face the outer peripheral surface of the exciting coil 3.

In this motor, a predetermined current is supplied to the exciting coil 3 of the stator 2 so that the rotating shaft 1 rotates together with the rotor yoke 4 at a predetermined speed.

A conventionally proposed automatic adjusting device 7 is shown in FIG.
As shown in FIGS. 3A and 3B, a disk-shaped case 8 made of a non-magnetic material such as aluminum and having an annular cavity 8a centered on the rotation shaft 1 is fixed to the rotation shaft 1. An annular magnet 9 having a predetermined attractive force is provided on the inner peripheral side of the annular cavity 8a.

The disc-shaped cavity 8 of the disc-shaped case 8
A plurality of, for example, six magnetic materials, for example, iron spherical balance weights 10, are arranged between the annular magnet 9 in FIG. 1A and the outer peripheral wall of the annular cavity 8a.

In this case, the annular cavity 8a is made such that the spherical balance weight 10 can move only slightly in the direction of the rotation axis in the annular cavity 8a, but can move freely in the circumferential direction. In this case, the spherical balance weight 10 is regulated by the magnet 9 on the inner peripheral side in the radial direction of the annular cavity 8a, and is regulated by the outer peripheral wall of the disc-shaped case 8 in the radial direction.

In such an automatic alignment device, the rotating shaft 1
When the rotation speed of the magnet 9 is relatively low, the attractive force of the magnet 9 is stronger than the centrifugal force acting on the balance weight 10,
The balance weight 10 is attracted to the outer peripheral surface of the magnet 9, and when the rotation speed of the rotary shaft 1 is increased to some extent, the centrifugal force becomes stronger than the attractive force of the magnet 9, and the balance weight 10 is attached to the outer peripheral wall of the annular cavity 8a. Operates as if pressed.

The operation of the self-centering device 7 will now be described. For example, the optical disk mounted on a turntable provided at, for example, the end of the rotary shaft 1 has no imbalance, the optical disk has no vibration, When there is no misalignment, the six balance weights 10 are positioned so as to face one of the balance weights via the center of rotation of the rotary shaft 1 and rotate with the rotary shaft 1.

When the optical disk has, for example, unbalance, the optical disk has vibration, and the rotating shaft 1 is not aligned, the six balance weights 10 move so as to face the unbalance position, and
For example, two opposing balance weights 10 move so as to oppose each other on the opposing line so as to cancel the imbalance between the balance weights 10.

At this time, the combined center of gravity of the optical disk (rotating body) and the center of gravity of the six balance weights 10 coincides with the rotation center of the rotating body. Therefore, the self-aligned optical disk (rotary body) can rotate without generating vibration.

That is, even when the optical disk having an imbalance in weight is rotated, the balance weight 10 can be rotated by the self-aligning action so that the six balance weights 1 are moved.
0 is moved as appropriate so that the position of the composite center of gravity coincides with the rotation center position.

[0016]

However, in the conventional self-aligning device using a plurality of balance weights 10, when the speed of the motor changes, the balance weight 10 is disposed in the annular cavity 8a. Due to the speed difference between the disc-shaped case 8 and the balance weight 10, the balance weight 10 moves in the annular cavity 8a, and there is a problem in that rolling noise and frictional sound occur at this time.

When the balance weight 10 is moved to balance, if only the circumferential weight in the annular cavity 8a is pressed, only the rolling friction is required. When the cavity 8a and the balance weight 10 are in contact with each other, sliding friction is also applied, which prevents the balance weight 10 from moving to an optimum position, and therefore, there is a disadvantage that accurate balance adjustment (alignment) cannot be performed. there were.

Further, the rotation speed of the rotating shaft 1 is accelerated from a relatively low state, and the sound when the balance weight 10 flies from the outer peripheral surface of the magnet 9 to the outer peripheral wall of the annular cavity 8a also causes a problem. Had become.

In view of the foregoing, it is an object of the present invention to make the above-mentioned sound small (quiet) and to perform highly accurate automatic alignment.

[0020]

SUMMARY OF THE INVENTION The present invention relates to a self-aligning apparatus in which a plurality of balance weights are arranged so as to freely roll in an annular cavity of a disc-shaped case about a rotation axis. An arc or V on the outer peripheral wall of the annular cavity
It is provided with a damping material having a letter-shaped groove.

According to the present invention, since the balance weight moves along the groove of the vibration damping material provided on the outer peripheral wall in the annular cavity, the rolling noise and the friction noise are reduced (quiet) and the balance weight is reduced. When the airplane flies from the outer peripheral surface of the magnet to the outer peripheral side of the annular cavity, the vibration damping material reduces the sound at this time (quiet).

Further, since the vibration damping material is provided with an arc-shaped or V-shaped groove, when the balance weight is moving, the balance weight and the rotational axis direction of the annular cavity are formed by the groove. The friction that hinders the movement of the balance weight is reduced, and highly accurate alignment (balance) can be obtained.

[0023]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of an automatic centering device according to the present invention will be described below with reference to FIG. In FIG. 1, parts corresponding to those in FIG. 6 are denoted by the same reference numerals.

In the example of FIG. 1, as shown in FIG. 6, the rotating shaft 1 of the motor is rotatably mounted on the stator 2 via the bearing 6, and the exciting coil 3 is fixed to the stator 2. A cylindrical rotor yoke 4 is fixed to the rotating shaft 1 so as to cover the exciting coil 3, and a predetermined magnetization is applied to the inner peripheral surface of the rotor yoke 4 so as to face the outer peripheral surface of the exciting coil 3. The magnet 5 is fixed.

In this motor, a predetermined current is supplied to the exciting coil 3 of the stator 2 so that the rotating shaft 1 rotates at a predetermined speed together with the rotor yoke 4.

A turntable for mounting an optical disk, for example, is attached to the end of the rotating shaft 1 of the motor.

In this example, as shown in FIGS. 1A and 1B,
An automatic alignment device 7 is provided on the rotating shaft 1 of the motor. As shown in FIGS. 1A and 1B, this self-centering device 7
A disk-shaped case 8 made of a non-magnetic material, for example, aluminum, having a circular cavity 8a centered on the rotating shaft 1 is fixed to the circular cavity 8a.
An annular magnet 9 having a predetermined attractive force is provided on the inner peripheral side of the magnet.

In this embodiment, as shown in FIGS. 1A and 1B, the disc-shaped case 8 is formed of, for example, rubber or the like having an arc-shaped groove on the outer peripheral wall on the outer peripheral side in the annular cavity 8a toward the inner peripheral side. The damping member 11 is provided so as to be fixed.

In this case, the arc of the arc-shaped groove of the damping material 11 is made slightly larger than the outer shape of a spherical balance weight 10 described later.

The annular cavity 8 of the disc-shaped case 8
a and the annular cavity 8 on the inner peripheral side in FIG.
A plurality of, for example, six magnetic materials, for example, iron spherical balance weights 10 are arranged between the outer peripheral side of a and the damping material 11 having the arc-shaped groove.

In this case, the annular cavity 8a is made such that the spherical balance weight 10 can move only slightly in the direction of the rotation axis but can freely move in the circumferential direction in the annular cavity 8a. Further, in this case, the spherical balance weight 10 is regulated by the magnet 9 on the inner peripheral side and is regulated by the vibration damping material 11 having the arc-shaped groove in the radial direction of the annular cavity 8a.

In the automatic alignment device according to the present embodiment,
When the rotation speed of the rotating shaft 1 is relatively low, the attracting force of the magnet 9 is stronger than the centrifugal force acting on the balance weight 10, so that the balance weight 10 is attracted to the outer peripheral surface of the magnet 9, and the rotation of the rotating shaft 1 When the number increases to a certain extent, the centrifugal force becomes stronger than the attractive force of the magnet 9, and the balance weight 10
It operates so as to be pressed against the arc-shaped groove of the damping material 11 of FIG.

The operation of the self-centering device 7 will now be described. The optical disk mounted on the turn cable provided at, for example, the end of the rotary shaft 1 has no imbalance, the optical disk has no vibration, When the shaft 1 has no deviation, the six balance weights 10 are positioned so as to face one of the balance weights through the center of rotation of the rotary shaft 1 and rotate with the rotary shaft 1.

Also, this optical disk has, for example, imbalance, this optical disk has vibration,
When there is misalignment, the six balance weights 10 move so as to face the unbalanced position, and, for example, the two balance weights 10 face each other so as to cancel the imbalance between the balance weights 10. It moves so that it may oppose in a line.

At this time, the center of gravity of the center of gravity of the optical disk (rotating body) and the center of gravity of the six balance weights 10 coincides with the center of rotation of the rotating body. Therefore, self-alignment is performed, and the optical disk (rotary body) can rotate without generating vibration.

That is, even if an optical disc having a weight imbalance is rotated, the balance weights 10 are rotated by the self-alignment action so that the six balance weights 10 are rotated.
Can be moved as appropriate to make the position of the composite center of gravity coincide with the position of the rotation center.

In this embodiment, as described above, the damping member 11 having an arc-shaped groove is provided on the outer peripheral side of the annular cavity 8a, and when the rotation speed of the rotating shaft 1 of the motor is increased to some extent, this balance is obtained. Since the weight 10 moves in the annular cavity 8a along the arc-shaped groove of the vibration damping material 11 due to centrifugal force, the balance weight 10 is axially floating in the annular cavity 8a. The balance weight 10 does not directly contact the upper and lower surfaces of the annular cavity 8a.

Therefore, according to the present embodiment, the balance weight 10 is connected to the annular cavity 8 while the rotation speed of the rotary shaft 1 is high to some extent.
When the balance weight 10 moves in the area a, the balance weight 10 does not come into contact with the upper and lower surfaces of the annular cavity 8a and moves along the arc-shaped groove of the vibration damper 11, so that there is an advantage that the sound becomes quiet.

Further, in this embodiment, when the balance weight 10 moves in the annular cavity 8a in an attempt to balance while the rotation speed of the rotating shaft 1 is high to some extent, when the balance weight 10 moves above the annular cavity 8a in the axial direction. Since there is no contact with the lower surface, friction that hinders movement is reduced, and there is an advantage that alignment can be performed with high accuracy.

In this embodiment, the rotation speed of the rotating shaft 1 is accelerated from a relatively low state, and when the balance weight 10 flies from the outer peripheral surface of the magnet 9 to the outer peripheral side of the annular cavity 8a, the control is performed. There is an advantage that the sound is quiet because it hits the vibration material 11.

FIGS. 2A and 2B show another embodiment of the present invention. 2 will be described. In FIG. 2, portions corresponding to those in FIG. 1 are denoted by the same reference numerals, and description thereof will be omitted.

In the examples of FIGS. 2A and 2B, a V-shaped groove is formed in a damping material 12 made of, for example, rubber or the like. The example of FIG. 2 is otherwise the same as that of FIG.
It can be easily understood that the same effect as that of the example of FIG. 1 can be obtained in the example of FIG.

FIGS. 3, 4, and 5 show other examples of the embodiment of the present invention. FIG. 3 shows an example in which the automatic alignment device 7 of FIG. 1 is incorporated in a turntable on which an optical disk is mounted, and FIG. 4 shows an example in which the automatic alignment device 7 of FIG. 1 is incorporated in a clamper for fixing an optical disk. FIG. 5 shows an example in which the self-centering device 7 of FIG. 1 is incorporated in a rotor of a motor. In describing the FIG. 3, FIG. 4, and FIG. 5 examples, portions corresponding to FIG. 1 are denoted by the same reference numerals, and detailed description thereof will be omitted.

In the example shown in FIG. 3, a turntable 2 on which an optical disk 13 is mounted is mounted on an end of a rotating shaft 1 of a motor.
Numeral 0 is formed of a disc-shaped non-magnetic material having an annular cavity 8a centered on the rotation shaft 1, for example, aluminum, and the turntable 20 also serves as a disc-shaped case.

In the example of FIG. 3, a chucking yoke 21 is provided on the upper surface of the turntable 20. Further, a clamper 22 for fixing the optical disk 13 by sandwiching the optical disk 13 placed on the turntable 20 on the turntable 20 is provided. The clamper 22 is attached to the back yoke 2 on the turntable 20 side of the support member 23.
4, the magnet 25 is fixed. The other configuration is the same as that of FIG.

In the embodiment of FIG. 3, the same operation and effect as those of the embodiment of FIG. 1 can be obtained.

FIG. 4 shows an example in which a clamper 22 for holding an optical disk 13 mounted on a turntable 20 attached to the end of the rotary shaft 1 of the motor on the turntable 20 is fixed in an annular cavity centered on the rotary shaft 1. The clamper 22 is formed of a disc-shaped non-magnetic material having aluminum 8a, for example, aluminum so that the clamper 22 also serves as a disc-shaped case.

In this case, the magnet 27 is fixed to the upper surface of the turntable 20 via the back yoke 26, and the chucking yoke 28 is provided on the turntable 20 side of the clamper 22. The other configuration is the same as that of FIG.

In the embodiment shown in FIG. 4, the same operation and effect as those in the embodiment shown in FIG. 1 can be obtained.

In the example shown in FIG. 5, an automatic alignment device 7 is provided on the rotating shaft 1 similarly to FIG. 1, and the outer periphery of the exciting coil 3 of the stator 2 of the motor is provided below the disk-shaped case 8 of the automatic alignment device 7. A cylindrical yoke 4a is fixed so as to surround the yoke 4a.
The magnet 5 having a predetermined magnetization is fixed to the inner peripheral surface of the magnet a so as to face the exciting coil 3. Other configurations are the same as those in the example of FIG.

It is needless to say that the same effects as those of the above-described FIG.

In the above embodiment, the balance weight 10
Has been described above, but the number of balance weights 10 may be two or more. In addition, the present invention is not limited to the above-described embodiment and does not depart from the gist of the present invention.
Of course, various other configurations can be adopted.

[0053]

According to the present invention, when the balance weight moves in the annular cavity while the rotation speed of the rotating shaft is high to some extent, the balance weight can contact the upper and lower surfaces of the annular cavity. There is an advantage that the sound moves quietly because it moves along the groove of the damping material.

Further, in the present invention, when the balance weight moves in the annular cavity in order to balance while the rotation speed of the rotating shaft is high to some extent, the balance weight contacts the upper and lower surfaces of the annular cavity in the axial direction. Since there is no friction, there is an advantage that the friction that hinders the movement is reduced and the alignment can be performed with high accuracy.

In the present invention, the rotation speed of the rotating shaft is accelerated from a relatively low state, and when the balance weight flies from the outer peripheral surface of the magnet to the outer peripheral side of the annular cavity, it hits the vibration damping material. The benefit is that the sound is quieter.

[Brief description of the drawings]

FIG. 1 shows an example of an embodiment of an automatic alignment device of the present invention, wherein A is a longitudinal sectional view and B is a transverse sectional view.

FIG. 2 shows another example of the embodiment of the present invention, wherein A is a longitudinal sectional view and B is a transverse sectional view.

FIG. 3 is a sectional view showing another example of the embodiment of the present invention.

FIG. 4 is a sectional view showing another example of the embodiment of the present invention.

FIG. 5 is a sectional view showing another example of the embodiment of the present invention.

FIG. 6 shows an example of a conventional self-centering device, wherein A is a longitudinal sectional view and B is a transverse sectional view.

[Explanation of symbols]

Reference Signs List 1 rotating shaft, 2 stator, 3 exciting coil, 4 rotor yoke, 5 magnet, 6 bearing, 7 self-aligning device, 8 disc-shaped case, 8a annular cavity, 9 magnet, 10 balance weight, 11, 12 damping material

Claims (1)

[Claims] 1. A self-aligning device in which a plurality of balance weights are arranged so as to freely roll in an annular cavity of a disk-shaped case about a rotation axis, wherein an arc-shaped or V-shaped portion is formed on an outer peripheral wall of the annular cavity. An automatic centering device comprising a damping member provided with a letter-shaped groove.