JPH11113213A - Disk driving equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a disk driving equipment which can stably prevent vibration in the range from low speed rotation to high speed rotation, by automatically adjusting the operation of an autobalancer according to the rotating speed, realize simple structure and miniaturization, and be manufactured at a low cost. SOLUTION: A shaft 3 is rotatably supported by a bearing 2 fixed to a stator core 1. A boss 4 is fixed on the tip side of the shaft 3. A turntable 5 is fixed on the boss 4. A cylindrical rotor yoke 6 whose bottom surface is opened is fixed to the boss 4 and surrounds the stator core 1. An annular step 8 is formed in the upper surface periphery of the rotor yoke 6. A cylindrical cover 9 whose bottom surface is opened is fixed to the boss 4 and surrounds the outside of the step 8, thereby forming a balancer moving space 15. The bottom surface 8a of the step 8 and a cover upper surface 9a are inclined to be higher toward the outer peripheral side, and the width in the radial direction is formed to be sufficiently larger than the diameter of a ball balancer 10.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement in a disk drive provided with an auto balancer mechanism.

[0002]

2. Description of the Related Art Generally, as a disk drive for a CD-ROM, a structure in which a turntable is press-fitted and fixed to a shaft of a spindle motor, and a CD is mounted on the turntable and rotated is generally used. When this disk drive device is rotated at high speed, vibrations due to the deviation of the center of gravity of the CD are directly applied to the shaft, and the vibration accuracy of the table surface is deteriorated, which may adversely affect the recording and reading of the CD.

In recent years, particularly, in recent years, the speed of the drive has increased the influence of the vibration, and as a countermeasure against this, a disk drive device equipped with an auto balancer mechanism incorporating a ball balancer formed of steel balls for correcting the balance has been developed. Have been. This auto balancer mechanism is either built into the turntable or built into the motor, but the one built into the turntable has a problem that the structure is complicated and the device becomes large, Incorporating into the device has the advantage that the structure of the device is simple and can be reduced in size.

A conventional disk drive in which an auto balancer mechanism is incorporated in the motor is configured as shown in FIG. 4, for example. The lower part of the shaft 3 is rotatably supported by a bearing 2 fixed to the center of the stator core 1, and a boss 4 is attached to the upper end of the shaft 3.
A turntable 5 is horizontally mounted on the boss 4, and a cylindrical rotor yoke 6 having an open bottom surface is mounted on the boss 4 below the turntable 5.
Is provided so as to surround the.

A magnet 7 is mounted on the inner peripheral side of the rotor yoke 6 so as to face the stator core 1, and an annular step 8 is provided on the outer peripheral portion of the upper surface of the rotor yoke 6 so as to surround the outer side. A cylindrical cover 9 having an open bottom surface is attached to the boss 4, and a ball balancer 10 formed of a plurality of steel balls is interposed between the cover 9 and the stepped portion 8. An annular balancer moving space 12 having a shape is formed. This disk drive is mounted on a motor substrate 13 and
D is placed and rotated.

As this disk drive rotates, the unbalance due to the deviation of the center of gravity of the CD as it rotates rotates the ball balancer 10 in the annular balancer moving space 12 as shown in FIG.
.. Move freely to maintain balance, prevent vibration of the shaft 3, and rotate the turntable 5 stably. However, in the conventional disk drive, since the ball balancer 10 only moves in the circumferential direction in the annular balancer moving space 12, the behavior of the ball balancer 10 at the time of low-speed rotation is unstable, and There is a possibility that it may increase, and a countermeasure has been desired.

[0007]

SUMMARY OF THE INVENTION The present invention eliminates the above-mentioned drawbacks, automatically adjusts the operation of the auto balancer according to the rotation speed, and can stably prevent vibration from low-speed rotation to high-speed rotation. An object of the present invention is to provide a disk drive device which has a simple structure, is small, and can be manufactured at low cost.

[0008]

According to a first aspect of the present invention, there is provided a disk drive device in which a lower portion of a shaft is rotatably supported by a bearing fixed to the center of a stator core, and a boss is provided on an upper end of the shaft. And a turntable is mounted on the boss, and a cylindrical rotor yoke having an open bottom is provided on the boss below the turntable so as to surround the stator core. A magnet is mounted on the peripheral side, an annular step is provided on the outer peripheral portion of the upper surface of the rotor yoke, and a cylindrical cover having a bottom surface opened so as to surround the outside is attached to the boss. A disk drive device in which an annular balancer moving space portion for accommodating a plurality of ball balancers is formed between the balancer moving space portion. The bottom surface of the annular step and the top surface of the cover are inclined so as to become higher toward the outer periphery, and the width in the radial direction is formed sufficiently larger than the diameter of the ball balancer, so that the ball balancer forms the balancer moving space. It is characterized in that it is formed so as to be movable in the circumferential direction and the radial direction.

Further, the disk drive device according to claim 2 is
The ball balancer comprises a steel ball and soft balls made of plastic or rubber, which are alternately arranged.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention is shown in FIG.
This will be described in detail with reference to FIG. A lower portion of the shaft 3 is rotatably supported by a bearing 2 fixed to the center of a stator core 1 formed of a coil, and a boss 4 made of metal is attached to the upper end of the shaft 3. A turntable 5 made of plastic is mounted horizontally. A cylindrical rotor yoke 6 having an open bottom surface is caulked to the boss 4 below the turntable 5 so as to surround the stator core 1, and is opposed to the stator core 1 on the inner peripheral side of the rotor yoke 6. A spindle motor is formed by attaching a magnet 7 to the spindle motor.

An annular step 8 is provided on the outer peripheral portion of the upper surface of the rotor yoke 6, and a cylindrical cover 9 having an open bottom surface is swaged to the boss 4 so as to surround the outer portion. An annular balancer moving space 15 is formed between the cover 9 and the step 8. The bottom surface 8a of the step portion 8 and the upper surface 9a of the cover 9 surrounding the step portion 8 constituting the balancer moving space 15 are both inclined so as to become higher toward the outer peripheral side, and have a radial width. Is formed sufficiently large to be about twice as large as the diameter of the ball balancer 10, and is formed in an annular shape having a parallelogram cross section so that the ball balancer 10 can move in the circumferential and radial directions in the balancer moving space portion 15. . Reference numeral 14 denotes a non-slip rubber mat attached to the upper surface of the turntable 5.

As shown in FIG. 2, in the disk drive device, when the spindle motor rotates, the imbalance due to the deviation of the center of gravity of the CD placed on the turntable 5 is compensated for by a ball balancer in the annular balancer moving space 15. .. Move freely in the circumferential direction and the radial direction to maintain balance, prevent vibration of the shaft 3, and rotate the turntable 5 stably. At low speed rotation, as shown in FIG. 1, no large centrifugal force is applied to the ball balancer 10,
Further, since the bottom surface 8a of the step portion 8 is inclined so as to be higher toward the outer peripheral side, the ball balancer 10 can balance while moving in the circumferential direction while being shifted toward the center side.

At the time of high-speed rotation, when a large centrifugal force is applied to the ball balancer 10, the bottom surface 8a inclined so as to become higher toward the outer peripheral side of the balancer moving space 15 rises toward the outer peripheral side, that is, in the radial direction. The balance can be obtained while moving in the circumferential direction on the outer peripheral side. Further, when the rotation speed becomes slow, the centrifugal force acting on the ball balancer 10 becomes small, and the effect of rolling the inclined bottom surface 8a toward the center side by its own weight and reducing the balance becomes small.

That is, according to the magnitude of the centrifugal force, the auto balancer mechanism does not act so much at low speed rotation and works effectively at high speed rotation, so that the vibration is balanced in a wide range from low speed to high speed rotation. Can be prevented. Also, since only the shapes of the rotor yoke 6 and the cover 9 are changed, the external shape of the device does not change and the structure is simple.

FIG. 3 shows another embodiment of the present invention. As a ball balancer housed in a balancer moving space 15, a ball balancer formed of steel balls 10a and a soft ball 10b such as plastic or rubber are used. Are alternately arranged. Since the soft balls 10b are interposed during the rotation, noise due to collision between the steel balls 10a is prevented and the operation is quiet.

In this case, the soft sphere 10b may be smaller in diameter than the steel ball 10a. Also ball balancer
The number of 10 can be arbitrarily selected. Further, the present invention is not limited to a drive device for a CD-ROM, but can be widely used as a drive device for a disk-shaped storage medium such as a DVD or an LD.

[0017]

As described above, according to the disk drive apparatus of the present invention, the bottom surface of the annular step portion and the upper surface of the cover that constitute the balancer moving space are inclined so as to become higher toward the outer peripheral side. The radial width is formed sufficiently larger than the diameter of the ball balancer, so that the ball balancer can move in the balancer moving space in the circumferential direction and the radial direction. By automatically adjusting the operation of the balancer, vibration can be stably prevented from low-speed rotation to high-speed rotation, and the structure is simple, small, and inexpensive.

[Brief description of the drawings]

FIG. 1 is a front vertical sectional view of a disk drive device according to an embodiment of the present invention.

FIG. 2 is a horizontal sectional view taken along line AA of the disk drive device shown in FIG.

FIG. 3 is a horizontal sectional view of a disk drive according to another embodiment of the present invention.

FIG. 4 is a front vertical sectional view showing a conventional disk drive.

FIG. 5 is a horizontal sectional view of the disk drive device shown in FIG. 4, taken along line BB.

[Description of sign]

 DESCRIPTION OF SYMBOLS 1 Stator core 2 Bearing 3 Shaft 4 Boss 5 Turntable 6 Rotor yoke 7 Magnet 8 Step 9 Cover 10 Ball balancer 12 Balancer moving space 13 Motor board 15 Balancer moving space

Claims (2)

[Claims] 1. A lower part of a shaft is rotatably supported by a bearing fixed to the center of a stator core, a boss is mounted on an upper end of the shaft, a turntable is mounted on the boss, and a lower part of the turntable is provided. To the boss
A cylindrical rotor yoke having an open bottom surface is provided so as to surround the stator core, a magnet is attached to the inner peripheral side of the rotor yoke in opposition to the stator core, and an annular step is formed on the outer peripheral portion of the upper surface of the rotor yoke. A cylindrical cover having a bottom surface opened so as to surround the outside is attached to the boss, and an annular balancer moving space for accommodating a plurality of ball balancers is formed between the cover and the step portion. In the disk drive device, the annular step bottom surface and the cover upper surface constituting the balancer moving space are inclined so as to become higher toward the outer peripheral side, and the radial width thereof is sufficiently larger than the diameter of the ball balancer. And a ball balancer formed so that the ball balancer can move in a circumferential direction and a radial direction in the balancer moving space. Location. 2. The disk drive device according to claim 1, wherein the ball balancer is constituted by steel balls and soft balls made of plastic or rubber, and these are alternately arranged.