JPH11126418A - Spindle motor for rotating disk provided with automatic balancer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To realize safe rotation of a spindle motor and also to enhance the reliability and prolong the life by always suppressing the generation of a shaft runout or vibration for disks having a small eccentricity through a large eccentricity. SOLUTION: A rotating plate 4 provided with an oblong holes 4b extending toward the outer periphery from the centroid is mounted on a rotary shaft 2, and by mounting an energizing spring 5 for holding the rotating plate 4 at the position where the rotary shaft normally becomes coaxial with the centroid of the rotating plate 4, the rotating plate 4 is slid in the outer peripheral direction along the oblong holes only at the rotating time of the largely vibrating eccentric disk so as to balance with the eccentricity of the disk by rotating by keeping the state the centroid is held in the direction diagonal with the centroid of the disk around the rotary shaft, then the vibration and the shaft runout are reduced, and also the durability and the reliability can be remarkably improved.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a spindle motor for rotating a magnetic disk, an optical disk, or the like, and more specifically, to reduce vibration and shaft runout of a spindle motor caused by mounting an eccentric disk. It is an improvement.

[0002]

2. Description of the Related Art Conventionally, in a spindle motor such as a CD-ROM, when a mounted disk is eccentric, vibration and shaft runout generated during rotation of the spindle motor become large, and set tracking is performed. In addition to causing errors, the burden on the bearings is also increased, and the reliability and durability may be significantly impaired. As means for solving this problem, for example, there is a spindle motor for disk rotation with an auto balancer in which a cylindrical case containing a metal ball with a space inside the cylinder is attached to the rotation shaft of a spindle motor for rotating the disk. . According to this method, the spindle motor vibrates,
When the run-out occurs, the ball in the cylindrical case moves in the case and gathers diagonally with the center of gravity of the disk about the rotation axis due to the reaction against the centrifugal force generated in the rotating disk. As a result, the load on the rotating shaft in the outer peripheral direction is reduced, so that the motor vibration,
There are ways to reduce shaft runout.

[0003]

However, the above-described method is effective as an effect of reducing vibration and shaft runout in the case of an eccentric disk in which the center of gravity and the center of rotation are shifted.
In a disk with small eccentricity, such as that usually used, the centrifugal force generated by the ball in the cylindrical case is larger than the centrifugal force generated by the disk, and as a result, the vibration and shaft runout generated by the spindle motor are increased. There was a disadvantage.

[0004] Therefore, an object of the present invention is to solve the above-mentioned problems, and to stably generate vibration during rotation of a spindle motor regardless of the presence or absence of eccentricity of a disk mounted with a simple structure. An object of the present invention is to provide a spindle motor for rotating a disk in which the reliability of bearing life and the durability are greatly improved by reducing shaft runout and reducing bearing load.

[0005]

In order to solve the above-mentioned problems, when rotating a disk having a large eccentricity, the disk is rotated by sliding around a rotation axis of a spindle motor so that the center of gravity is located diagonally to the center of gravity of the disk. The rotating plate to be rotated may be arranged on the spindle motor rotating shaft, and a spring may be arranged to urge the rotating plate to rotate while maintaining the center of gravity of the rotating plate at a position coinciding with the rotating shaft when the disk which is originally small in eccentricity rotates. .

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention has a slot on a rotating shaft of a spindle motor for rotating a disk which is larger than the shaft diameter so as to be rotatable and slidable from the center toward the outer periphery. When the disk with small eccentricity is rotated by attaching a spring between the rotating shaft and the rotating plate so that the center of gravity of the rotating plate is normally biased to the position where the spindle motor rotating shaft coincides with the rotating plate, Because the rotating plate and the rotating shaft of the spindle motor rotate by the biasing spring, the vibration of the spindle motor due to the rotation of the disk does not increase, and when the disk with large eccentricity rotates, the centrifugal force and vibration of the disk cause The rotating plate slides along the elongated hole against the urging force of the spring, and the center of gravity of the eccentric disk and the rotating plate By the center of gravity is rotated while positioned in a diagonal direction, the load on the rotating shaft of the spindle motor is reduced, it can be achieved by the so suppress small vibrations. Further, the rotating plate may be mounted on a shaft provided at the center of rotation of the chuck plate, which rotates coaxially with the spindle motor rotating shaft, in order to clamp the disk.

[0007]

FIG. 1 is a sectional view of a main part of a spindle motor according to a first embodiment of the present invention, and FIG. 2 is an enlarged view of a main part of a component of the present invention in FIG. In FIG. 1, reference numeral 1 denotes a rotor portion of a spindle motor, 2 denotes a rotary shaft that rotates integrally with the rotor, and 3 denotes a turntable fixed to the rotary shaft by press fitting or the like and for mounting a disk. Reference numeral 4 denotes a rotary plate which is attached to a long hole 4b provided in the center so as to freely rotate through the rotary shaft and slide along the long hole 4b, and 5 is wound around the rotary shaft. The torsion coil spring is mounted so that the arm is locked to the projection 4a provided on the rotating plate 4.

As shown in FIG. 2, an elongated hole 4b is provided at the center of the rotary plate 4 from the center of gravity of the rotary plate 4 toward the outer periphery. It can be slid smoothly toward
The spring 5 has a predetermined load and the center of gravity of the rotating plate 4 and the rotating shaft 2.
Are locked to the rotating shaft 2 and the projections 4a provided on the rotating plate 4 so as to press the rotating plate in the direction opposite to the arrow in the figure so that they are coaxial.

At this time, the slot 4b of the rotary plate 4 is
Is a long hole having a size that allows a small gap with the rotating shaft 2 so that the sliding hole can be freely slid around the rotating shaft 2 at the same time as it can slide smoothly on the rotating shaft 2. The inner diameter of the coil of the turned torsion coil spring 5 is also wound around the rotating shaft with a small gap, so that the rotating shaft 2
The rotation plate 4 and the spring 5 can freely rotate around the center.

With the above arrangement, when the disk having originally small eccentricity rotates, the vibration and shaft runout which occur are small, and the rotating plate is held at a position where the center of gravity of the rotating plate coincides with the rotating shaft by the pressing load of the urging spring. When rotating a disk with large eccentricity, the rotating plate is centered on the rotating shaft against the pressing force of the spring due to the vibration and the centrifugal force generated by the rotating plate due to the deflection of the rotating shaft. The eccentric disk is eccentrically rotated by moving the center of gravity to a position diagonal to the center of gravity of the disk around the rotation axis, and offsets the centrifugal force generated by the eccentric disk. Vibration and shaft runout can be reduced, and even when rotating disks with different eccentricity, stable low vibration can be achieved, and shaft vibration can be kept small. Burden to only be able to reduce, it becomes possible to realize a superior spindle motor of long life and reliability.

[0011]

Second Embodiment FIG. 3 is an enlarged view of a main part of an example in which a tension coil spring is used as a spring. In the figure, a tension coil spring 5 is used in place of the torsion coil spring, and the same effect as in the above embodiment can be obtained in this case. If the thick portion 4c is formed on the outer peripheral portion of the rotating plate 4 as in the present embodiment, the inertia can be increased, which is effective for balancing with the eccentric disk.

[0012]

Third Embodiment FIG. 4 is an enlarged view of a main part of an example in which a leaf spring is used as a spring. In the drawing, the plate spring 5 is further configured, and in this case, the same effect as that of the above-described embodiment can be obtained. Further, as in this embodiment, the rotating plate 4 may be made of a resin having excellent slidability, and a metal ring 6 having a high specific gravity may be attached to the outer periphery.

[0013]

Fourth Embodiment FIG. 5 is a sectional view of a main part of an embodiment in which a disk is accommodated in a chuck plate for clamping a disk, in which 7 is a chuck plate case, and 8 is a chuck plate case.
Is a rotation center axis of a chuck plate coaxial with the rotation shaft 2, 4 is a rotation plate mounted similarly to the first embodiment, 5 is a spring, 9 is a disk clamped by a chucking plate. In this case, the same effect as described above can be obtained.

The present invention is not limited to the above embodiments but can be implemented with appropriate modifications. For example, a sleeve made of resin or metal having excellent slidability may be rotatably mounted on a contact portion between the biasing spring and the rotating shaft.

[0015]

As described above, according to the present invention, when a disk with large eccentricity rotates, the rotating plate slides in the outer peripheral direction due to the centrifugal force generated, and the center of gravity of the rotation is centered on the rotation axis. By moving the disk diagonally with respect to the center of gravity of the disk to achieve balance, the centrifugal force of the disk can be reduced, and vibration and shaft runout can be reduced. Since the shaft runout is also small, the center of gravity of the rotating plate is held down and held by the biasing spring at a position coaxial with the rotating shaft, so that vibration and shaft runout do not worsen. It is possible to realize a spindle motor for rotating a disk with small shaft runout.

[Brief description of the drawings]

FIG. 1 is a sectional view of a main part of a spindle motor according to a first embodiment of the present invention.

FIG. 2 is an enlarged view of a part in FIG.

FIG. 3 is an enlarged view of a main part of an example in which a tension coil spring is used as the spring in FIG.

FIG. 4 is an enlarged view of a main part of an example in which a leaf spring is used as the spring in FIG.

FIG. 5 is a structural view of a main part of another embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Rotor part 2 Rotation axis 3 Turntable 4 Rotation plate 4a Projection part 4b Slot 5 Urging spring

Claims (8)

[Claims] 1. A disk rotation spindle motor having a media mounting turntable fixed to a rotation shaft output end, wherein:
A rotating plate having an elongated hole provided so as to be able to freely slide a predetermined distance from the center of weight toward the outer peripheral direction and to be freely rotatable about the axis of rotation, is mounted through the elongated hole, and When the spindle motor stops or rotates at a low speed, a biasing spring that holds the centrifugal force generated by the rotating plate at a position where the center of weight of the rotating plate coincides with the spindle motor rotation axis, A spindle motor for rotating a disk with an auto balancer engaged with a rotating shaft and the rotating plate. 2. A torsion coil spring, wherein the coil is penetrated through the rotation shaft, and both ends of the torsion coil spring are engaged with projections provided on the rotation plate, and are provided in the rotation plate. 2. The disk motor according to claim 1, wherein the rotating plate is urged along the elongated hole to a position where the rotating shaft and the center of gravity thereof coincide with each other. 3. The spindle motor according to claim 1, wherein the spring engaged with the rotating plate and the rotating shaft is a tension coil spring. 4. The spindle motor according to claim 1, wherein the spring engaged with the rotating plate and the rotating shaft is a leaf spring. 5. The spindle motor for rotating a disk with an auto balancer according to claim 1, wherein the thickness of the outer peripheral portion of the rotary plate is increased and inertia is increased. 6. The auto-rotating device according to claim 1, wherein the rotating plate is made of a resin having excellent slidability, and a metal ring having a high specific gravity is mounted on an outer periphery of the rotating plate. Spindle motor with balancer for disk rotation. 7. The sleeve according to claim 1, wherein a sleeve made of resin or metal excellent in slidability is rotatably mounted on a contact portion between the urging spring and the rotating shaft. A spindle motor for rotating a disk with an auto balancer according to any one of the preceding claims. 8. The spindle motor according to claim 1, wherein the rotary plate is housed in a chuck plate for clamping a disk.