JP2001298898A - Self-balancing device and motor using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain superior balance correcting action of a member 21 for balancing and improve stability of rotation with simple and small constitution. SOLUTION: By eliminating a part of a circular main body 21a with an unbalance part 21b, mass necessary for balance correcting action is effectively ensured by using the whole peripheral region of the main body 21a, at least one out of the outer diameter size or the thickness is made possible to be set small remarkably, and the whole of the device is miniaturized and made flat. An extreme overhung structure is excluded and a very stable rotating state is obtained from a state of low speed rotation to a state of high speed rotation.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an automatic balancing device having a function of canceling a rotational imbalance of a rotating body, and a motor using the same.

[0002]

2. Description of the Related Art Generally, industrial machines, household appliances,
Alternatively, an automatic balancing device is often employed in various rotary driving devices used in a computer or the like in order to cancel a rotational imbalance of a rotating body including a rotating shaft. As the automatic balancer, various structures have been conventionally proposed. For example, in the device described in JP-A-10-257710, as shown in FIG.
A balancing member 3 composed of a hollow disk-shaped case body is attached to a rotating shaft 2 which is an output shaft of the motor 1, and a plurality of balancing spheres 4, 4 Are arranged to be freely movable. When the rotation speed of the motor 1 exceeds the resonance rotation speed CR, each of these balance spheres 4 starts to move in a direction opposite to the position of the center of gravity of the rotation body including the rotation shaft 2 and the balancing member 3. , Thereby balancing the rotation of the rotating body,
The vibration of the rotating body is reduced, and the rotation is stabilized.

[0003]

However, in such a conventional automatic balancing apparatus, the plurality of balance spheres 4 are likely to be in an unstable state at low speed rotation below the resonance rotation speed CR, so that each of the spheres 4 collides with each other. May produce sound or be damaged. Furthermore, each of the balance spheres 4
The contact resistance of the balance sphere 4 becomes considerably large especially at the time of high-speed rotation where the viscosity of the air flow increases. As a result, it is impossible to accurately arrange the respective balance spheres 4 at an appropriate balance position. Stabilization may not be achieved sufficiently.

On the other hand, for example, Japanese Patent Application Laid-Open No. H11-178272
As shown in FIG. 9, there is proposed an automatic balancing device in which two balancing members 5 and 5 formed in a fan shape are rotatably mounted on a rotating shaft 6 as shown in FIG. However, the above-mentioned problem is basically solved. However,
This proposed device has a problem in that the balancing members 5 and 5 have an extremely cantilevered structure and thus lack support stability. In particular, a resonance phenomenon is likely to occur in a low-speed rotation region. Further, since each of the balancing members 5 and 5 is formed in a substantially sectorial shape in a plane, the outer diameter must be increased to secure a predetermined mass, and the entire device is also increased in size. is there.

Further, in the proposed device, the two balancing members 5 and 5 are connected to the rotating shaft 6 in a low rotation region below the resonance rotation speed.
Due to the structure of the spring-plate-shaped rotation locking members 7 and 7 that rotate integrally with the same, even if the two balancing members 5 and 5 are once moved to the balance position, the two rotating members 5 and 5 are not rotated in the next rotation operation. , 5 are again moved to a predetermined fixed position and locked by the rotation locking members 7, 7, and both balancing members 5, 5 are fixed again in an unbalanced state. I will. Therefore, such balancing members 5, 5
In view of the rotation locking structure, there is a problem that the rotation stability in the low-speed rotation region is not good.

Accordingly, the present invention provides a simple and compact configuration,
It is an object of the present invention to provide an automatic balancing device and a motor using the same, which can obtain a good balance correcting action of the balancing member and can improve rotation stability particularly in a low-speed rotation region. .

[0007]

According to a first aspect of the present invention, there is provided an apparatus having a plurality of balancing members which are rotated by a rotating shaft, wherein the rotating member has a rotational speed exceeding the resonance speed. In the automatic balancing device configured to cancel the rotational imbalance of the rotating body including the rotating shaft by the balance correcting action of the plurality of balancing members in the above, each of the balancing members is rotatable with respect to the rotating shaft. And a unbalanced portion formed by removing a part of the circular body.

According to the second aspect of the present invention, the unbalanced portion according to the first aspect is formed by removing a part of the circular main body from a hole or a concave portion obtained by removing a part of the circular body in a plane substantially circular shape or a part thereof. At the same time, two circular body parts are attached so as to overlap in the axial direction with respect to the rotating shaft.

Further, according to the third aspect of the present invention, there is provided a plurality of balancing members which are rotated by a rotating shaft, and the balance correcting action of the plurality of balancing members when the rotational speed of the rotating body is exceeded. An auto-balancing device configured to cancel the rotational imbalance of a rotating body including the rotating shaft, wherein each of the balancing members includes a center circular portion rotatably mounted on the rotating shaft; An unbalanced portion arranged at a predetermined distance radially outward from the portion, and a connecting portion connecting the unbalanced portion to the center circular portion, wherein the unbalanced portion is It is formed so as to have an appropriate mass that contributes to the balance correction action, and the mass of the central circular portion is larger than the mass of the unbalance portion. Are, and each of the plurality of the balancing member is arranged in a positional relationship that rotates in a non-contact with each other around the rotation axis.

Further, in the invention according to claim 4, the radius of the central circular portion is larger than the radius when the planar shape of the unbalanced portion according to claim 3 is converted into a circle with respect to the balance correcting action. It is set large.

According to a fifth aspect of the present invention, the radius of the central circular portion is 0.3 L with respect to the distance L from the axis center of the rotating shaft to the position of the center of gravity of the unbalanced portion. It is set above.

Further, in the invention according to the sixth aspect, there is provided a plurality of balancing members which are rotated by a rotation shaft, and the balance correcting action of the plurality of balancing members when the rotational speed of the rotating body is exceeded. An automatic balancing device configured to cancel a rotational imbalance of a rotating body including the rotating shaft, wherein a rotation locking member that rotates the respective balancing members integrally with the rotating shaft in a rotation region equal to or less than the resonance rotation speed. Is provided, and the rotation locking member is provided on an outer peripheral portion of the support portion attached so as to rotate integrally with the rotation shaft, and substantially the entire circumference of each of the balancing members is provided. An annular sliding contact portion disposed so as to be able to abut on the outer peripheral surface of each of the balancing members so as to surround the balancing member. Outer circumference of member Is formed of an elastically deformable material such that spaced radially outwardly from the.

Furthermore, in the invention according to claim 7, the annular sliding contact portion according to claim 6 is provided so as to rise in the axial direction from the outer peripheral edge of the support portion formed in a substantially circular planar shape. Slits, each of which comprises at least one sliding contact piece and which are capable of deforming each sliding contact piece, are provided between a pair of circumferentially adjacent sliding contact pieces.

Further, in the invention according to claim 8, the balancing member according to claim 6 is provided in a pair in the axial direction, and a pair of rotation locking members are provided corresponding to the pair of balancing members. The sliding contact piece of the one side rotation locking member and the sliding contact piece of the other side rotation locking member are arranged so as to face each other in the axial direction in a circumferentially non-contact state. The arrangement is such that they mesh with each other.

On the other hand, in the ninth aspect of the present invention, each of the balancing members according to the sixth aspect includes a circular main body rotatably attached to the rotating shaft, and the balance main body is attached to the circular main body. Is provided with an unbalanced portion formed by removing a part of the circular main body.

According to the tenth aspect of the present invention, each of the balancing members according to the sixth aspect includes a center circular portion rotatably attached to the rotation shaft, and a radially outward portion from the center circular portion. An unbalanced portion arranged at a predetermined distance away from the center portion, and a connecting portion connecting the unbalanced portion to the center circular portion, wherein the unbalanced portion has an effect on the balance correcting action. While being formed so as to have an appropriate mass to contribute, the mass of the central circular portion is formed to be larger than the mass of the unbalanced portion, and the plurality of balancing members Each is arranged in a positional relationship of rotating about the rotation axis in a non-contact state with each other.

Further, according to an eleventh aspect of the present invention, a motor having a rotating shaft is provided with the automatic balancing device according to any one of the first to tenth aspects.

According to the first, ninth or eleventh aspect of the present invention, the mass required for the balance correcting action is efficiently secured by utilizing the entire peripheral area of the circular main body. Therefore, for example, Japanese Patent Application Laid-Open
In the case of the same mass, at least one of the outer diameter and the thickness is set to be significantly smaller than that provided with a fan-shaped balancing member as described in 178272. As a result, the entire device can be reduced in size and flattened. In addition, the adoption of the circular main body will eliminate the extreme cantilever structure as in the past,
An extremely stable rotation state can be obtained from the low-speed rotation state to the high-speed rotation state.

At this time, as in the second aspect of the present invention,
If the unbalanced portion is formed by a hole or a concave portion in which a part of the circular body is removed in a substantially circular shape in a plane, even if the size of the unbalanced portion is changed, the position of the center of gravity does not change. In addition, the mass adjustment of the balancing member is facilitated.

According to the third, tenth or eleventh aspect of the present invention, the mass required for the balance correcting action is:
Since it is ensured efficiently by using the entire peripheral area of the central circular portion, it is compared with a conventional one provided with a fan-shaped balancing member as described in, for example, JP-A-11-178272. When the mass is the same, at least one of the outer diameter and the thickness is set to be small, and the entire device can be reduced in size and flattened. In addition, the adoption of the central circular portion eliminates the conventional extreme cantilever structure, so that an extremely stable rotation state can be obtained from a low-speed rotation state to a high-speed rotation state.

At this time, if the central circular portion is set to be larger than the unbalanced portion, the central portion of the balancing member can be further stabilized. Therefore, the above-described operation can be reliably obtained.

On the other hand, according to the invention described in claim 6 or 9 or 10 or 11, the rotation locking member has the annular sliding contact portion arranged annularly over substantially the entire circumference.
Regardless of the rotational position of each balancing member, it can be fixed by the annular sliding contact portion of the rotation locking member.
Therefore, after each balancing member is once in the balanced state, at the time of the next rotation start, each balancing member is already fixed in the balanced state by the annular sliding contact portion. The rotation stability in the rotation region is improved, and also in the high-speed rotation region, the balance shifting operation of each balancing member is performed smoothly and in a short time.

According to a seventh aspect of the present invention, in the rotation locking member having the annular sliding contact portion, a plurality of sliding contact pieces are provided so as to rise in the axial direction along the outer peripheral edge of the support portion. Is easily formed.

[0024] At this time, if a pair of rotation locking members provided corresponding to the pair of balancing members are arranged facing each other in the axial direction, as in the invention according to claim 8, the pair of rotation locking members can be arranged. The locking action on the balancing member is performed evenly by each of the pair of rotation locking members, and the balance correction action is performed accurately.

[0025]

Embodiments of the present invention will be described below in detail with reference to the drawings. First, a CD to which the present invention is applied
To explain the overall structure of the ROM drive unit, a mechanical chassis 11 of the CD-ROM drive unit 10 shown in FIG. 1 has a spindle motor 13 for rotating and driving a recording disk 12, and a laser beam for the recording disk 12. An optical pickup device 14 that irradiates and writes or reads information is mounted. The recording disk 12 is mounted on a disk table 139 (see FIG. 2) mounted on a rotating shaft of the spindle motor 13.

The optical pickup device 14 is mounted so as to be able to reciprocate with respect to a pair of parallel guide shafts 15, 15 attached to the mechanical chassis 11.
A light beam emitted from a laser light source (not shown) is applied to the recording disk 12 through the objective lens 16 and the reflected light from the recording disk 12 is detected.

On the other hand, the spindle motor 13 is provided with a hollow cylindrical bearing holder 132 mounted so as to stand substantially vertically with respect to the main body frame 131, as shown in FIG. The bearing holder 1
The bearing member 133 is press-fitted into the hollow interior side of 32. The bearing member 133 includes two bearing portions in the axial direction.
A wide variety of bearing members such as oil-impregnated plain bearings, bearing bearings, metal bearings, or hydrodynamic bearing devices can be employed.

A rotary shaft 134 is rotatably supported at the center of the bearing holder 132 via the bearing member 133.
A stator core 135 made of a laminated body such as a silicon steel plate is fitted on the outer peripheral wall surface of the. This stator core 1
An insulating layer is formed by coating on the surface of 35, and a winding 136 is wound around a portion corresponding to each salient pole portion of the stator core 135 via the insulating layer.

Further, at the position immediately above the bearing holder 132 in FIG. 2, a central portion of a substantially cylindrical rotor case 137 formed in a hollow cylindrical shape is fixed to the rotary shaft 134. A ring-shaped rotor magnet 138 is fixed to the inner peripheral surface side of an annular wall portion provided on the outer peripheral portion of the rotor magnet 138. The inner peripheral surface side of the rotor magnet 138 is arranged so as to approach each salient pole portion of the stator core 135 from the radial outside.

On the other hand, a substantially disk-shaped disk table (turntable) 139 is fixed to the protruding portion of the rotating shaft 134 in the upper part of the drawing, and is located immediately below the disk table 139 in the axial direction. A pair of balancing members 21 and 21 constituting an automatic balancing device 20 described later.
However, through the appropriate bearing members 22, 22,
4 so as to be rotatable. The disk table 139 is fixed by press-fitting a rotary shaft press-fitting hole formed in a central portion to the rotary shaft 134, and has a substantially conical positioning protrusion 139a formed in an annular shape so as to include the fixed portion. Thereby, a recording disk (not shown in FIG. 1) mounted on the disk table 139 is held at a predetermined position.

Next, the structure of the automatic balancing device 20 will be described. First, as described above, a pair of balancing members 21,
21 is rotatably mounted on the rotary shaft 134 directly or via bearing members 22, 22 made of a bearing bearing, a metal bearing, or the like. Due to the balance correcting action of the device 20, the rotating body including the rotating shaft 134, the disk table 139, and the like is moved to the resonance rotational speed C of the rotating body.
The configuration is such that the rotational imbalance that occurs when the rated rotation exceeds R is canceled. In addition, a resin sheet material 22a made of a highly slidable resin material such as Teflon (registered trademark) is sandwiched in the center portion of each of the balancing members 21 so as to sandwich each balancing member 21 from both sides in the axial direction. The respective balancing members 21 are arranged in contact with each other, and the rotation of the respective balancing members 21 is smoothly performed by interposing the respective resin sheet materials 22a.

More specifically, the pair of balancing members 2
1 has a planar circular main body portion 21a as shown in FIGS. 2 and 3, and a part of the outer peripheral edge portion of the circular main body portion 21a has a small-diameter through hole. The structure is formed so as to be cut out by an unbalance portion 21b made of. The circular main body 21
As described above, the fixing hole 21c formed at the center position of "a" is rotatably attached to the rotating shaft 134, and a pair of such circular main bodies 21a are close to each other in the axial direction. It is arranged to be. As the circular main body 21a of each of the pair of balancing members 21, a material having a large specific gravity, such as iron, stainless steel, or lead, is preferably used, but a variety of materials can be used. is there.

The size and position of the unbalance portion 21b are appropriately determined according to the unbalance amount of the entire rotating body including the recording disk 12, and the size of the unbalance portion 21b is provided. However, the position of the center of gravity of the circular main body member 21a is
By being deviated to the opposite side from the formation position, a balance correcting action as described later can be obtained.

It is sufficient that the unbalanced portion 21b is obtained by removing a part of the circular main body 21a. Therefore, the unbalanced portion 21b does not have to be a through hole as in the present embodiment, but may be, for example, a flat circular concave portion. It is also possible to form from.

On the other hand, each such balancing member 21 is provided with a rotation locking member 23 as shown in FIGS. The rotation locking member 23 has a function of rotating the respective balancing members 21 integrally with the rotation shaft 134 when the rotating body is rotating at a low speed at or below the resonance rotation speed CR. , The rotating shaft 134
And a substantially disk-shaped support portion 23b to which a central boss portion 23a is fixed.
A large number of sliding contact pieces 23c,... are integrally provided on the outer peripheral edge of the b.
Each of these sliding contact pieces 23c constitutes an annular sliding contact portion by being annularly arranged along the entire outer peripheral edge of the support portion 23b. The inner peripheral wall surface of each sliding contact piece 23c is configured to press against the outer peripheral surface of each balancing member 21. The sliding force of each sliding contact piece 23c causes each balancing member 23c to slide. 21 is fixed so as to rotate integrally with the rotation shaft 134.

On the other hand, of the large number of sliding contact pieces 23c,
A slit 23d formed of a narrow gap is provided between the two sliding contact pieces 23c adjacent in the circumferential direction so as to extend in the axial direction. In addition, each of these sliding contact pieces 23
The entire rotation locking member 23 including the rotation member c is formed from an elastic material such as a deformable spring material, and when the rotating body is in a high-speed rotation state at the resonance rotation speed CR or more, the rotational centrifugal force is generated. Thereby, the free end side portion (upper portion in the drawing) of each of the sliding contact pieces 23c is configured to expand toward the outside in the radial direction.

In this embodiment having such a configuration,
First, a rotating body including the rotating shaft 134, the disk table 139, the recording disk 12, the automatic balancer 20, and the like,
When the motor is started from the rotation stop state by the spindle motor 13 and is in a low-speed rotation region that does not exceed the resonance rotation speed CR of the rotating body, the two balancing members 21 described above are used.
Since the rotating body integrally rotates with the rotating shaft 134 by the locking action of each sliding contact piece 23c of the rotation locking member 23, the relative speed between the two becomes "0".
The balance correcting action described later is realized early.

When the rotation speed of the spindle motor 13 increases and the centrifugal force increases, and when the rotation speed of the spindle motor 13 reaches around the resonance rotation speed CR, each sliding contact of the rotation locking member 23 is performed. The piece 23c expands due to a large centrifugal force, whereby each of the balancing members 21
Is released, and free rotation of the balancing members 21 and 21 with respect to the rotation shaft 134 is allowed. The rotational speed of the spindle motor 13 is the resonance rotational speed CR
After that, the balancing members 21 and 21 that have become freely rotatable with respect to the rotation shaft 134 move individually in a direction to cancel the eccentricity of the rotating body, which is a so-called pull-in phenomenon. And a balance correcting action is imparted to the rotating body.

As described above, each of the balancing members 21 and 21
When the recording disk having a rotational imbalance is rotated, the self-movement is appropriately performed by the balance correcting action, whereby the position of the composite center of gravity is located on the rotating shaft 134. As a result, the rotating body rotates without vibrating,
Even if a recording disc with rotational imbalance is mounted,
Since the composite center of gravity is rotated while being positioned on the rotation shaft 134, the rotation is continued without vibration.

On the other hand, when the rotation speed of the rotating body is reduced after such automatic balancing is performed, the sliding contact pieces 23c of the rotation locking member 23 are reduced as the rotation speed decreases.
Against the reduced centrifugal force, again presses against the outer peripheral surfaces of the balancing members 21 and 21 to exert a locking force. At this time,
Since the respective balancing members 21 and 21 are in a balanced state, there is no eccentricity in the rotating body. In this state, the holding action by the rotation locking member 23 is performed. It remains canceled. Since the balance state is maintained even after the rotation of the spindle motor 13 is stopped, when the spindle motor 13 is driven again, the eccentricity of each balancing member 21 does not occur.
The rotation starts very smoothly.

At this time, in this embodiment, particularly, in the present embodiment, the mass required for the balance correcting operation is the circular main body portion 21a.
Is efficiently secured by utilizing the entire circumference area of the conventional art, and compared with a conventional apparatus provided with a fan-shaped balancing member as described in, for example, JP-A-11-178272, In the case of the same mass, at least one of the outer diameter dimension and the thickness will be set to be significantly smaller,
The entire device can be reduced in size and flattened.

Further, by adopting the circular main body portion 21a, an extreme cantilever structure as in the prior art is eliminated, and an extremely stable rotation state can be obtained from a low-speed rotation state to a high-speed rotation state.

At this time, in the present embodiment, the unbalanced portion 21b composed of a hole or a concave portion in which a part of the circular main body 21a is removed in a substantially circular shape in a plane is employed. Is changed, the position of the center of gravity of the unbalanced portion 21b does not change, so that the mass adjustment of the balancing member 21 is facilitated.

Further, in the present embodiment, the rotation locking member 2
3 is provided with a sliding contact piece (annular sliding contact portion) 23c arranged annularly over substantially the entire circumference, so that the rotation locking member 23 is provided regardless of the rotational position of each balancing member 21. Can be fixed by the sliding contact piece 23c. Therefore, after each balancing member 21 is once in the balanced state, at the time of the next rotation start, each balancing member 21 is already fixed in the balanced state by the sliding contact piece 23c, and as a result, In particular, the rotation stability in the low-speed rotation region is improved, and also in the high-speed rotation region, the balance shifting operation of each balancing member 21 is performed smoothly and in a short time.

As described in the present embodiment, such a rotation locking member 23 raises a plurality of sliding contact pieces (annular sliding contact portions) 23c in the axial direction along the outer peripheral edge of the disk-shaped support portion 23b. With such a configuration, it can be easily formed.

On the other hand, also in the embodiment shown in FIGS. 6 and 7, a pair of balancing members 41, 41 are overlapped in the axial direction so as to rotate around the rotation axis (reference numeral 134 in FIG. 2). Are arranged so as to rotate in a non-contact state with each other. More specifically, each balancing member 41 in the present embodiment includes a central circular portion 41a rotatably attached to the rotation shaft 134, and an outer peripheral surface of the central circular portion 41a includes: Disc-shaped unbalanced portion 4 via a connecting portion 41b composed of an arm-shaped member
1c is connected. That is, the unbalanced portion 41c is arranged radially outward from the center circular portion 41b by a predetermined distance, and
c is formed so as to have an appropriate mass that contributes to the balance correcting action, and the connecting portion 41b is
It is formed so as to have a mass that does not substantially contribute to the balance correcting action.

At this time, the radius r of the central circular portion 41a is
1 is set to be larger than the radius r2 of the unbalanced portion 41c (r1> r2), and the rotating shaft 1
The radius r1 of the center circular portion is set to be 0.3 L or more with respect to an interval L (≒ r1 + r2) from the center of the axis 34 to the position of the center of gravity of the unbalanced portion 41c (r1). ≧ 0.3L). The unbalanced portion 41c is not limited to a circular shape as in the present embodiment, but has a planar shape other than a circular shape, and when the planar shape has a circular shape with respect to the balance correcting action. The radius r1 of the central circular portion is set to be larger than the radius of the converted circular shape when converted into

Further, the balancing member 41 according to the present embodiment.
, The same rotation locking member 2 as in the above-described embodiment.
3 (see reference numeral 23 in FIGS. 2 and 5).

In such an embodiment, the central circular portion 41
By providing a, a necessary mass is secured by utilizing the entire circumference of the rotating shaft 134, and a conventional fan-shaped balancing for a fan as described in, for example, JP-A-11-178272 is used. In the case of the same mass, at least one of the outer diameter and the thickness is set to be smaller than that having the member, so that the entire apparatus can be reduced in size and flattened. Further, by employing the center circular portion 41a, an extremely cantilever structure as in the related art is eliminated, so that an extremely stable rotation state can be obtained from a low-speed rotation state to a high-speed rotation state.

At this time, if the central circular portion 41a is set to be larger than the unbalanced portion 41c as in this embodiment, the central portion of the balancing member 41 will be more stabilized. In addition, the above-described operation can be reliably obtained.

The embodiments of the present invention made by the inventor have been specifically described above. However, 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 rotation locking member 23 as shown in the above-described embodiment is connected to a pair of balancing members 21, 21 (4).
1, 41), and a pair of the rotation locking members 23, 23 face each other in the axial direction. If 41) is arranged so as to be locked, the locking action on the pair of balancing members is performed evenly by each of the pair of rotation locking members 23, and the balancing action is performed smoothly.

In the second embodiment described above, the two unbalanced portions 41c, 41c are arranged so as to be displaced in the axial direction so as not to contact each other. Connection part 41b
By setting the lengths of the unbalanced portions 41c, 41c so that the radial positions of the unbalanced portions 41c, 41c are in a non-contact state, the two unbalanced portions 41c, 41c are arranged on substantially the same plane. As a result, the thickness in the axial direction can be reduced. In this case, the masses of the unbalanced portions 41c, 41c are mutually changed so as to compensate for the difference in the radial position between the unbalanced portions 41c, 41c.

Further, a plurality of the unbalance portions 21b or 41c in each of the balancing members 21 or 41 may be arranged.

Further, the unbalance portions 21b or 41c of the balancing members 21 or 41 are not limited to the circular shape as in the above-described embodiments.
Other shapes, such as elliptical and polygonal, can be employed as well.

Furthermore, the present invention can be used in a similar manner other than the CD-ROM drive device as in the above-described embodiment, and a variety of motors can be applied, such as a servo motor and an air motor. Can be applied.

[0057]

As described above, according to the first, ninth or eleventh aspect of the present invention, by removing a part of the circular main body by the unbalance portion, the mass required for the balance correcting action can be reduced. The entire circumference area of the circular main body is efficiently secured, and at least one of the outer diameter and the thickness can be set to be significantly smaller, so that the entire apparatus can be reduced in size and flattened. It is configured to obtain an extremely stable rotation state from low-speed rotation to high-speed rotation by eliminating the cantilever structure, so it has a simple and small configuration and good balance correction function of the balancing member. In addition, it is possible to improve the rotational stability and achieve a superior effect that the size can be reduced while improving the performance.

Further, the invention according to claim 2 is characterized in that, in addition to the above-mentioned claim 1, an unbalanced portion comprising a hole or a concave portion in which a part of a circular main body is removed in a substantially circular shape in a plane is adopted. Even when the size of the unbalance portion is changed, the position of the center of gravity is not changed, and the adjustment of the mass of the balancing member is facilitated. Therefore, the effect according to claim 1 is further improved. Can be.

Further, according to the third, tenth or eleventh aspect of the present invention, the unbalance portion is provided at the center circular portion via the connecting portion, so that the mass required for the balance correcting action can be reduced. Efficiently secure using the entire peripheral area of the device, at least one of the outer diameter and the thickness can be set to be small, and the entire device is reduced in size and flattened, and the extreme cantilever structure is eliminated. Since it is configured to obtain a very stable rotation state from the low-speed rotation state to the high-speed rotation state, it is possible to obtain a good balance correcting action of the balancing member with a simple and small configuration, and to rotate. An excellent effect is obtained that the stability can be improved, and the size can be reduced while improving the performance.

On the other hand, according to the invention of claim 4 or 5, in addition to the above-mentioned claim 3, the central side portion of the balancing member is further stabilized by setting the central circular portion larger than the unbalanced portion. Therefore, the above-described effect according to claim 3 can be further improved.

Further, according to the invention of claim 6, 9 or 10 or 11, an annular sliding contact portion arranged annularly over substantially the entire circumference is provided on the rotation locking member, and each balancing member is in any rotation position. After each balancing member is once placed in a balanced state, each balancing member is fixed in a balanced state by the annular sliding contact portion, thereby improving rotational stability particularly in a low-speed rotation region. In addition, since the balance shifting operation of each balancing member is performed smoothly and in a short time even in the high-speed rotation region, the rotation stability can be improved and the performance can be improved.

Further, the invention according to claim 7 can be easily formed by providing a plurality of sliding contact pieces so as to rise in the axial direction along the outer peripheral edge of the support portion in addition to the above-described claim 6. Therefore, productivity can be improved in addition to the effect according to claim 6 described above.

Further, according to the invention of claim 8, in addition to the above-mentioned claim 6, a pair of rotation locking members provided corresponding to the pair of balancing members are arranged facing each other in the axial direction. Since the locking action on the balancing member is uniformly performed by each of the pair of rotation locking members so that the balance correcting action is performed with high accuracy, the effect according to claim 6 described above can be achieved. It can be further improved.

[Brief description of the drawings]

FIG. 1 shows a CD-R as an example of an apparatus to which the present invention is applied.
FIG. 3 is an explanatory perspective view showing the appearance of an OM drive unit.

FIG. 2 is an explanatory longitudinal sectional view showing an embodiment of a motor with an automatic balancing device employed in the CD-ROM drive unit shown in FIG. 1;

FIG. 3 is an explanatory plan view showing an embodiment of the automatic balancing device shown in FIG. 2;

4 is an external perspective explanatory view showing the automatic balancing device shown in FIG. 3;

FIG. 5 is an external perspective explanatory view showing an embodiment of another portion of the automatic balancing device shown in FIG. 2;

FIG. 6 is an explanatory plan view showing a structure of an automatic balancing apparatus according to another embodiment of the present invention.

FIG. 7 is an external perspective explanatory view showing the automatic balancing apparatus shown in FIG. 3;

FIG. 8 is an explanatory longitudinal sectional view showing an example of a conventional motor with an automatic balancing device.

FIG. 9 is an explanatory plan view showing an improved example of the conventional automatic balancing device.

[Explanation of symbols]

 Reference Signs List 10 CD-ROM drive unit 12 Recording disk 13 Spindle motor 14 Optical pickup device 134 Rotating shaft 139 Disk table (turn table) 20 Automatic balance device 21 Balancing member 21a Circular body portion 21b Unbalanced portion 22 Bearing member 23 Rotation locking member 23b Disc-shaped support portion 23c Sliding contact piece (annular sliding contact portion) 23d Slit 41 Balancing member 41a Center circular portion 41b Connecting portion 41c Unbalanced portion

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 3J011 AA04 BA02 BA10 CA02 5D109 DA11 5H607 AA12 BB07 BB09 BB14 BB17 BB25 CC01 CC03 DD14 EE38

Claims (11)

[Claims] 1. A rotating body having a plurality of balancing members rotated by a rotating shaft, the rotating body including the rotating shaft by a balance correcting action of the plurality of balancing members when the rotational speed of the rotating body is exceeded. In the automatic balancing device configured to cancel the rotational imbalance of the above, each of the balancing members removes a circular main body rotatably attached to the rotating shaft and a part of the circular main body. And an unbalance portion formed as described above. 2. The unbalanced portion comprises a hole or a concave portion obtained by removing a part of the circular main body in a substantially circular plane or a part of the circular main body, and the circular main body includes the rotating shaft. 2. The automatic balancing device according to claim 1, wherein two components are mounted so as to overlap with each other in the axial direction. 3. A rotating body having a plurality of balancing members rotated by a rotating shaft, the rotating body including the rotating shaft by a balance correcting action of the plurality of balancing members when the rotational speed of the rotating body is exceeded. In the automatic balancing device configured to cancel the rotational imbalance of the above, each of the balancing members includes a center circular portion rotatably attached to the rotation shaft, and a predetermined radially outward portion from the center circular portion. An unbalanced portion arranged at a distance and a connecting portion connecting the unbalanced portion to the center circular portion, wherein the unbalanced portion appropriately contributes to the balance correcting action. And the mass of the central circular portion is formed to be larger than the mass of the unbalanced portion, and Each use members, automatic balancing apparatus characterized by being arranged in a positional relationship rotated without contacting each other around the rotation axis. 4. The method according to claim 1, wherein the plane shape of the unbalanced portion is smaller than a radius when the plane shape is converted into a circle with respect to a balance correcting action.
4. The automatic balancing device according to claim 3, wherein the radius of the center circular portion is set to be larger. 5. The center circular portion has a radius set to 0.3L or more with respect to a distance L from an axis center of the rotation shaft to a center of gravity of the unbalanced portion. 3. The automatic balancer according to 3. 6. A rotating body including a plurality of balancing members rotating by a rotating shaft, wherein the rotating body includes the rotating shaft by a balance correcting action of the plurality of balancing members when the rotational speed of the rotating body is exceeded. An automatic balancing device configured to cancel the rotational imbalance of the above, further comprising a rotation locking member for integrally rotating the respective balancing members with a rotation shaft in a rotation region equal to or lower than the resonance rotation speed, A member provided on an outer peripheral side portion of the support, the member being provided so as to rotate integrally with the rotating shaft; and a member for surrounding each of the balancing members so as to surround substantially the entire periphery of the member for balancing. An annular sliding contact portion disposed so as to be in contact with the outer peripheral surface of the member, wherein the annular sliding contact portion is arranged in a radial direction from the outer peripheral surface of each of the balancing members in a high-speed rotation region exceeding the resonance rotation speed. Move outward Automatic balancing apparatus characterized by being formed from an elastically deformable material so. 7. The annular sliding contact portion comprises three or more sliding contact pieces provided so as to rise in an axial direction from an outer peripheral edge of a support portion formed in a substantially circular shape in a plane, and is adjacent in a circumferential direction. 7. The automatic balancing device according to claim 6, wherein slits are provided between the pair of sliding contact pieces to make the respective sliding contact pieces deformable. 8. A pair of balancing members are provided in the axial direction, and a pair of rotation locking members are disposed so as to face in the axial direction corresponding to the pair of balancing members, The sliding contact piece of one side rotation locking member and the sliding contact piece of the other side rotation locking member are arranged so as to alternately mesh with each other in a circumferentially non-contact state. 7. The automatic balancer according to 6. 9. Each of the balancing members includes a circular main body rotatably attached to the rotating shaft, and a part of the circular main body is removed from the circular main body. 7. The automatic balancing device according to claim 6, further comprising an unbalance portion formed as described above. 10. Each of the balancing members includes a central circular portion rotatably attached to the rotation shaft, and an unbalanced portion arranged at a predetermined distance radially outward from the central circular portion. And a connecting portion connecting the unbalanced portion to the center circular portion, wherein the unbalanced portion is formed so as to have an appropriate mass that contributes to the balance correcting action. In addition, the mass of the center circular portion is formed to be larger than the mass of the unbalanced portion, and each of the plurality of balancing members is in a non-contact state with each other around the rotation axis. 7. The automatic balancing device according to claim 6, wherein the automatic balancing device is arranged to rotate in a positional relationship. 11. A motor having a rotating shaft, comprising the automatic balancing device according to any one of claims 1 to 10.