JP2000152554A - Rotating body driving apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain excellent vibration correcting function with simple constitution. SOLUTION: In a static state, a weight 44 for canceling unbalance load of an unbalance load canceling mechanism 4 and a weight 45 for position fixing are held around a rotation center O by a center part fixing means 46. In the range of comparatively low speed rotation when rotation is started and the number of revolution is increasing, the weight 45 is made to leave the fixing means 46 and to move toward the radial outside, and fixed on an outer end position by an outer peripheral part fixing means 43. When the number of revolution increases and becomes comparatively high, the weight 44 is made to leave the fixing means 46 and to move toward the radial outside. As a result, mass eccentricity load is canceled and balance is obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rotating body driving device for rotating a rotating body by a rotating force of a motor unit.

[0002]

2. Description of the Related Art In general, a rotary drive device in which various rotating members such as a flywheel and a recording medium disk are connected to an output portion of a motor unit to rotate at high speed is widely used in various kinds of devices. I have. In such a high-speed rotation drive device, when the center of gravity of the rotating body is at a position deviated from the rotation center, a large vibration is generated even by a slight imbalance of the rotating body based on the eccentricity of the rotating body. It will be. Since the unbalanced vibration is caused by centrifugal force, the amplitude increases as the rotation speed increases, and when the rotation speed (primary critical speed) corresponding to the resonance point is reached, the mechanical vibration increases. In some cases, the vibration may be large enough to cause destruction.

In view of such circumstances, various high-speed rotation driving devices employ a means for correcting the imbalance of the rotating body with high accuracy in minute units of about mg.cm. For example, in a grindstone spindle of a grinding machine, while monitoring the generated vibration using a vibration sensor, a fluid is driven into pockets arranged in a circumferential shape, thereby actively correcting imbalance. In addition, CD-
Since a rotating system including a removable media disk such as a ROM or a DVD has an eccentricity which is almost always required for the reason described later, a spindle motor of a rotary drive device handling these high-speed rotating disks is particularly required. In order to cancel the eccentric vibration in the high-speed rotation range,
For example, there is one that employs a relatively inexpensive vibration correction device using a ball or the like.

[0004]

However, in the case of the active vibration correcting device using the vibration sensor as described above, the device becomes very expensive, and it is difficult to adopt it in a wide variety of consumer devices. In practice, it is often impossible.
Further, the latter vibration correction device of a rotary drive device for a removable medium such as a CD-ROM or DVD is configured at low cost, but tends to be unable to follow recent high-speed rotation. is there. That is, the eccentricity of the removable media disk is caused by uneven ink on the label surface,
It is caused by various factors such as thickness unevenness during molding, misalignment, or error in mechanical configuration, or mounting error when mounting the drive, but even with its slight eccentricity, in recent high-speed environments, Such a problem may occur.

(1) The optical pickup cannot pick up recorded data. (2) It causes unpleasant acoustic noise. (3) With miniaturization of the device, it becomes difficult to provide a sufficient vibration isolation structure in a limited space. (4) Even in the case where a mechanism for suppressing unbalanced vibration is provided, the reproduction signal cannot be reliably picked up in the high-speed rotation condition described above. (5) When there is no or small eccentricity, eccentricity is rather promoted, which causes eccentric vibration.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a rotating body driving device having a simple structure and having a very good vibration correcting function.

[0007]

In order to achieve the above object, a motor unit, a rotating body support member attached to an output shaft of the motor unit so as to rotate integrally or relatively thereto, and the rotating body A rotating body held by a supporting member, and an offset load canceling mechanism for canceling an eccentric load of a rotating part including the rotating body and the rotating body support member, and the rotating part is rotated by the motor unit. In a rotating body driving device that is driven to rotate, the offset load canceling mechanism is provided so as to rotate relative to the rotating body support member, and the offset load canceling mechanism is configured to rotate the output shaft. A pair of offset load canceling weights and position fixing weights, which are arranged to be reciprocally movable in the radial direction in each of the two opposite regions that are radially symmetric with respect to the center; While holding the offset load canceling weight and the position fixing weight in the rotation center side region, each of the offset load canceling weight and the position fixing weight are caused by different centrifugal forces corresponding to different rotation speeds. A center fixing means for detaching radially outward, and a position fixing weight detached from the center fixing means by a relatively small centrifugal force corresponding to a low rotational speed among the rotational speeds different in height. Outer peripheral portion fixing means for locking at a predetermined radially outer end position, positioning the entirety of the offset load canceling mechanism and rotating integrally with the rotating portion, and The offset load canceling weight is separated radially outward from the center fixing means side by a relatively large centrifugal force corresponding to the high rotational speed of the rotating load offset weight. And so as to balance.

According to the second aspect of the invention, the positions of the centers of gravity of the offset load canceling weight and the position fixing weight according to the first aspect are held in the rotation center side region by the center fixing means. In this state, the eccentric load canceling weight and the position fixing weight are arranged in the respective arrangement areas with respect to the rotation center, and the center of gravity of the position fixing weight is adjusted to the center of gravity of the eccentric load canceling weight. More radially outward,
In addition, the position of the center of gravity of the entire eccentric load canceling mechanism is set at a position shifted from the center of rotation to the position area side of the position fixing weight.

Further, according to the third aspect of the present invention, the offset load canceling weight according to the second aspect is formed of a substantially U-shaped member having a greater mass than the position fixing weight. In a state where the offset load canceling weight is held on the rotation center side by the center fixing means, the front end sides of the two opposing sides of the U-shape are arranged with a position fixing weight body more than the position of the rotation center. It is arranged so as to protrude toward the region side.

Further, in the invention according to claim 4, the outer peripheral portion fixing means according to claim 1 comprises an annular wall portion defining a radially outer end position of the position fixing weight, and the position fixing weight. A fixed locking groove formed so as to be circumferentially continuous with the inner peripheral surface of the annular wall so as to engage a part of the weight, and the position fixing weight is provided. On the outer peripheral side end surface, there is provided an engagement protrusion that fits into the fixed locking groove.

On the other hand, in the fifth aspect of the present invention, the center fixing means according to the first aspect holds the offset load canceling weight and the position fixing weight by magnetically attracting them to the rotation center side region. Including a magnet body to be made.

According to the first aspect of the present invention, in the stationary state, both the offset load canceling weight and the position fixing weight of the offset load canceling mechanism are held around the rotation center by the center fixing means. However, in a relatively low rotation region in which the rotation is started and the number of rotations is increasing, the position fixing weight body separates from the center fixing means and starts to move outward in the radial direction. At this time, the rotating surface slightly tilts in the direction of the eccentricity due to the eccentricity of the rotating portion including the rotating body, so that the position fixing weight body moves in the tilting direction, that is, in the direction of the eccentricity of the rotating portion. Moving. The position fixing weight that has reached the radially outer end is locked at the outer end position by the outer peripheral portion fixing means, whereby the entire offset load canceling mechanism is positioned, and the offset load canceling mechanism is rotated with the rotating portion. It is rotated integrally. When the rotation speed further increases and the rotation speed becomes relatively high, the offset load canceling weight body is separated from the center fixing means and starts to move outward in the radial direction. It acts to balance and offset the eccentric load. Thereafter, the rotation is continued with the entire rotating part being balanced with high precision.

The offset load canceling function of the rotating part according to the first aspect of the present invention is characterized in that the positional relationship or the shape or the engagement / locking relationship of the center of gravity of the offset load offset weight and the position fixing weight is determined. With the configuration as described in the second or third or fourth aspect of the present invention, the operation can be performed more reliably.

Further, if a magnet body is used as the central portion fixing means as in the invention according to the fifth aspect, the weight for offset load canceling and the weight for position fixing are necessary and sufficient with a simple structure. It can be satisfactorily held with a strong force.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an embodiment in which the present invention is applied to a media rotation drive device that handles a removable media disk (hereinafter, simply referred to as a disk) such as a CD-ROM or a DVD will be described.

First, as shown in FIGS. 1, 2 and 3, a disk-shaped disk support plate 3 is integrated with an output shaft 2 of a motor unit 1 by press-fitting, shrink fitting, bonding or the like. It is fixed so as to rotate. A molded case 41 of an eccentric load canceling mechanism 4 is provided on the center side of the disk support plate 3 with a metal bearing 4 with respect to the output shaft 2.
2, and the offset load canceling mechanism 4 and the disk support plate 3 are relatively rotated. On the other hand, an annular wall 43 surrounding the mold case 41 is provided upright on the disk support plate 3 so as to be concentric with the output shaft 2, and the annular wall 43 is provided in the circular inner space of the annular wall 43. A mold case 41 is rotatably arranged.

The molded case 41 of the offset load canceling mechanism 4 has a wide main case portion 41a having a large accommodating space including a central portion where the output shaft 2 is disposed, and one side in the radial direction from the main case portion 41a. The main case portion 41a and the sub case portion 41b are integrally formed by a reinforcing case portion 41c having a substantially arc-shaped wall portion in a plane. Are linked. The main case part 41a and the sub case part 41
b is disposed so as to extend in the diameter direction including the rotation center in the internal space of the above-described annular wall portion 43,
The respective portions corresponding to the radially outer ends of the case portions 41a and 41b are arranged so as to be close to the inner peripheral surfaces of the annular wall portion 43 on the diametrically opposite sides. At this time, the radial outer end portion of the main case portion 41a is formed as an arc-shaped closed surface along the inner peripheral surface of the annular wall portion 43, but the radial outer end portion of the sub case portion 41b is formed. Is
The annular wall 43 is formed in an opening that opens toward the inner peripheral surface.

The main case portion 41a and the sub case portion 41
In each of the internal spaces b, a large and relatively large mass offset offset weight 4 formed in a substantially U-shaped plane is used.
4 and a position fixing weight 45 formed in a substantially rectangular parallelepiped shape and having a relatively small mass are mounted so as to be reciprocally movable in the radial direction. That is, the pair of offset load canceling weights 44 and the position fixing weights 45 are arranged in both regions on the opposite side in the radial direction with respect to the center of rotation, respectively, so that they can be freely moved in the radial direction. It is configured.

A hollow cylindrical annular magnet 46 is fixed to the outer peripheral surface side of the metal bearing 42 rotatably mounted on the output shaft 2 by bonding or the like. It is configured to be rotated together with the case 41. The annular magnet 46 constitutes a center fixing means for holding the offset load canceling weight 44 and the position fixing weight 45 in the center side region. Based on the relationship of the position of the center of gravity, the offset load canceling weight 44 and the position fixing weight 45 are separated from each other radially outward by different centrifugal forces corresponding to different rotational speeds. I have. More specifically, the position fixing weight 45 is rotated by a small centrifugal force corresponding to a lower predetermined rotational speed.
6 and the weight 44 for offset load offset,
The positional relationship of the center of gravity such that the center of gravity is separated from the annular magnet 46 by a large centrifugal force corresponding to a higher predetermined rotation speed is set as follows.

First, consider a rotation stop state in which the offset load canceling weight 44 and the position fixing weight 45 are held in the rotation center side region by the annular magnet 46. In this state, the position G1 of the center of gravity of the offset load canceling weight 44 is set at an inner position of the radius r1 close to the rotation center O. This is because the tip portions of both opposing side portions 44a, 44a in the U-shape of the offset load canceling weight 44 face the region on the opposite side from the position of the rotation center O, that is, toward the position fixing weight 45 side. Is formed so as to protrude.

On the other hand, the center of gravity G2 of the position fixing weight 45 is different from the offset load canceling weight 44 by the rotation center O.
Is set further outward in the region on the opposite side in the radial direction with respect to the center of gravity G of the position fixing weight 45.
The set radius r2 of 2 is set to be considerably larger than the set radius r1 of the center of gravity G1 of the offset load canceling weight 44 (r2> r1).

The set positions of the center of gravity G1 and G2 of the offset load canceling weight 44 and the position fixing weight 45 are determined by the entire center of gravity G0 of the offset load canceling mechanism 4.
Is determined to be a position shifted by an appropriate amount from the rotation center O to the position area side of the position fixing weight 45, and the center of gravity G0 of the offset load canceling mechanism 4 is located at a radius r0 with respect to the rotation center O. It is set at a position shifted toward the fixing weight 45 side.

Further, the above-mentioned annular wall portion 43 is provided as an outer peripheral portion fixing means for defining an outer end position of the position fixing weight 45, and the annular wall portion 43 is provided.
A fixed locking groove 43a for fitting the position fixing weight 45 is formed on the inner peripheral surface of the fixing member. The fixed locking groove 43 a is formed in the shape of an inner peripheral gear, and has an uneven tooth surface that is circumferentially continuous along the inner peripheral surface of the annular wall portion 43. On the other hand, on the outer end surface in the radial direction of the position fixing weight 45, an engaging projection 4 that can be fitted in the fixed locking groove 43a is provided.
5a are provided so as to project in a spire shape toward the outside in the radial direction, and when the position fixing weight 45 moves to the outer end position in the radial direction, the engaging projection 45a is fixed to the fixing locking groove. 43a, and as a result, the position fixing weight 45 is fixed at the fitting position.

Further, a protective cap 6 is mounted on the outer side of the annular wall portion 43 via a disk-shaped protective plate 5 so as to cover the entire eccentric load canceling mechanism 4. A disk (not shown) is mounted on the surface side so as to be freely attached and detached.

In this embodiment, first, in the stationary state shown in FIG. 4A, both the offset load canceling weight 44 and the position fixing weight 45 of the offset load canceling mechanism 4 are provided. Is an annular magnet 46 as a center fixing means.
, And is attracted and held around the rotation center O.
Next, when the motor unit 1 is energized to start rotation, the disk (not shown) starts rotating together with the disk support plate 3, and when the rotation speed reaches a predetermined rotation speed in the middle of rising, First, from the positional relationship of the center of gravity and the magnitude relationship of the mass, the position fixing weight 45 separates from the annular magnet 46 with a small centrifugal force corresponding to a relatively low rotation, and starts to move outward in the radial direction.

At this time, the disk and the disk support plate 3
Since the rotating portion including the eccentricity is almost always in the state of eccentricity (see paragraph (0004)), the rotating surface of the rotating portion is oriented in the direction of the eccentricity by the eccentricity load based on the eccentricity. It rotates with a slight inclination. Therefore, the position fixing weight 45 moves in the direction of inclination of the rotating surface, that is, in the direction of the eccentricity of the rotating portion. When the position fixing weight 45 reaches the outer end in the radial direction, the engaging projection 45a of the position fixing weight 45 is fitted into the fixing locking groove 43a of the annular wall portion 43 to be in the engaged state. The entirety of the offset load canceling mechanism 4 is locked at the outer end position to perform positioning, and the entirety of the offset load canceling mechanism 4 rotates integrally with the rotating portion including the disk support plate 3 and the disk. start.

In this case, the position fixing weight 45 moves in the direction to increase the eccentric load.
The position fixing weight 45 is designed to be sufficiently small and lightweight with respect to the rotating portion including the disk and the offset load canceling weight 44, and as a result, the position fixing weight 45 has the above-described outer shape. The increase in the eccentric load due to the one-way movement is negligible when compared with the entire rotating portion and the eccentric load canceling weight 44.

When the rotational speed further increases after the positioning of the offset load canceling mechanism 4 is performed, the offset load canceling weight body 44 that has been attracted to the rotation center side region by the annular magnet 46 until then. On the other hand, even greater centrifugal force acts, and when the rotational speed reaches a predetermined high rotational speed close to the rotational speed of the disk, the offset load canceling weight 44 separates from the annular magnet 46 by a large centrifugal force. , Begin to move radially outward.

Then, immediately before the rotation speed of the disk,
As shown in FIG. 4B, the offset load canceling weight 44 reaches the outer end position and is fixed. As a result, the eccentric load canceling weight 44 having a large mass balances the eccentric load of the rotating portion including the disk described above, and the eccentric load originally existing in the rotating portion is offset by the eccentric load. The weight 44 completely cancels or is in a state close to it. Thereafter, since the rotation is continued with the entire rotating part being balanced with high precision, the rotational vibration is suppressed to an extremely small level.

The function of offsetting the load of the eccentric center of gravity of the rotating part is based on the positional relationship, shape, and engagement / locking relationship of the center of gravity of the eccentric load canceling weight 44 and the position fixing weight 45 in the present embodiment. This is ensured by being configured as described above.

Further, as described above, if the magnet body 46 as in the present embodiment is used as the center fixing means, the weight 44 for offset load offset and the weight 45 for position fixing have a simple structure. Is satisfactorily held with the required force.

When the rotation of the motor unit 1 is stopped, the motor unit 1 returns to the original position shown in FIG.
Both the offset load canceling weight 44 and the position fixing weight 45 of the offset load canceling mechanism 4 are attracted and held around the rotation center O by the annular magnet 46 as the center fixing means.

Although the embodiments of the present invention made by the inventor have been specifically described above, the present invention is not limited to the above-described embodiments, and can be variously modified without departing from the gist thereof. Needless to say. For example, the movement of the weight can be performed using an actuator such as a VCM (voice coil motor).
At this time, if the position of the weight body is moved to a position that just balances by using a vibration sensor or the like, more accurate adjustment can be performed.

The rotating object to which the present invention can be applied is not limited to the media disk as in the above-described embodiment, but may be any of various other rotating objects such as a polygon mirror and a flywheel. The present invention can be similarly applied to the case where is used.

[0035]

As described above, according to the first aspect of the present invention, in the stationary state, both the offset load canceling weight and the position fixing weight of the offset load canceling mechanism are rotated around the center of rotation by the center fixing means. In a relatively low rotation region where rotation is started and the number of rotations is rising, the position fixing weight is separated from the center fixing means and moved outward in the radial direction, and is moved outward by the outer peripheral fixing means. By fixing to the end position, when the rotation speed further increases and the rotation speed becomes relatively high, the offset load canceling weight body is detached from the center fixing means and moved radially outward, so that the rotating portion In order to obtain an inexpensive and high-precision rotating body driving device, it is possible to provide a very good vibration correction function with a simple configuration, since the rotational balance is balanced so as to cancel the eccentric load of the rotating body. Can

Further, claim 2 or claim 3 or claim 4
The invention described in addition to the invention described in claim 1 described above,
The positional relationship between the center of gravity of the weight for offset load and the weight for position fixing, which more reliably performs the offset load offset function of the rotating part,
Alternatively, since the shape or the engagement / locking relationship is defined, the above-described effects can be further enhanced.

Further, according to the fifth aspect of the present invention, the use of a magnet body as the central portion fixing means makes it possible to provide the offset load canceling weight and the position fixing weight with a simple structure and a sufficient and sufficient force. , The productivity can be improved in addition to the effects described above.

[Brief description of the drawings]

FIG. 1 is an external perspective explanatory view showing a structure of a media disk rotation drive device according to an embodiment of the present invention.

FIG. 2 is an enlarged plan view showing an eccentric load canceling mechanism of the media disk rotation driving device shown in FIG. 1;

FIG. 3 is an explanatory cross-sectional view of the offset load canceling mechanism shown in FIG. 2;

FIGS. 4A and 4B are explanatory plan views illustrating the operation of the offset load canceling mechanism shown in FIGS. 1 and 2, wherein FIG. 4A shows a low rotation state immediately after the start of rotation, and FIG. In the high rotation state.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Motor part 3 Disk support plate (rotary body support member) 4 Unbalanced load cancel mechanism 41 Mold case 42 Metal bearing 43 Annular wall part (outer peripheral part fixing means) 43a Fixed locking groove 44 Unbalanced load canceling weight 45 Position fixing Weight 45a Engagement protrusion 46 Annular magnet (center fixing means) G0, G1, G2 Center of gravity O Rotation center

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 5D109 AA01 AA10 DA20 5H605 AA05 BB05 BB14 CC03 CC08 DD01 EA07 EA29 EB06 EB16 5H607 AA04 BB01 BB14 BB25 CC01 DD02 DD16 EE38

Claims (5)

[Claims] 1. A motor unit, a rotating body supporting member attached to an output shaft of the motor unit so as to rotate integrally or relatively thereto, a rotating body held by the rotating body supporting member, A eccentric load canceling mechanism for canceling the eccentric load of the rotating part including the rotated body and the rotator supporting member, wherein the rotating part is driven to rotate by the motor unit. The offset load canceling mechanism is provided so as to rotate relative to the rotating body support member, and the offset load canceling mechanism is provided on the opposite side that is radially symmetric with respect to the rotation center of the output shaft. In each of the two regions, a pair of offset load canceling weights and position fixing weights arranged so as to be reciprocally movable in the radial direction, and these offset load canceling weights and position fixing weights are provided. A center fixing means for holding in the turning center side region, and separating each of the offset load canceling weight and the position fixing weight to the radially outward side by different centrifugal forces corresponding to different rotation speeds in height. The position fixing weight body detached from the center fixing means side by a relatively small centrifugal force corresponding to a low rotational speed among the rotational speeds different in height is locked at a predetermined radial outer end position. Outer peripheral portion fixing means for positioning the entirety of the offset load canceling mechanism and rotating integrally with the rotating portion, a relatively large centrifugal force corresponding to a high rotational speed among the rotational speeds different in height. By separating the offset load canceling weight body radially outward from the center fixing means side,
The rotating body driving device, wherein the offset load canceling weight is balanced with the rotating portion. 2. The eccentric load canceling weight with respect to the center of rotation when the center of gravity of each of the eccentric load canceling weight and the position fixing weight is held in the rotation center side region by the center fixing means. And the center of gravity of the position fixing weight is set radially outside the position of the center of gravity of the offset load canceling weight, and the offset load canceling mechanism is arranged. 2. The rotating body driving device according to claim 1, wherein the position of the center of gravity of the entire body is set at a position shifted from the center of rotation toward the arrangement area of the position fixing weight. 3. The offset load canceling weight is formed of a substantially U-shaped member having a larger mass than the position fixing weight, and the offset load canceling weight is controlled by the center fixing means. In the state held in the rotation center side area, the front ends of both the opposite sides of the U-shape are arranged so as to protrude more toward the position fixing weight body arrangement area side than the rotation center position. 3. The rotating body driving device according to claim 2, wherein: 4. The outer peripheral portion fixing means includes: an annular wall portion defining a radially outer end position of the position fixing weight member; and the annular wall portion engaging a part of the position fixing weight member. And a fixed locking groove formed so as to be circumferentially continuous with the inner circumferential surface of the portion. The fixed locking groove is fitted to the outer circumferential end surface of the position fixing weight. 2. The rotating body driving device according to claim 1, further comprising a mating engaging projection. 5. The center fixing means includes a magnet body for magnetically attracting and holding the offset load canceling weight and the position fixing weight in a rotation center side region.
The rotating body driving device as described in the above.