JP2003235202A - Automatic equilibrium system of motor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To make it possible to carry out an equilibrium operation with accuracy in a simple constitution without enlarging the system by moving freely a balance spheric body smoothly. <P>SOLUTION: A narrow space (S) between an outer circumferential upright walls 20a2 and 20b2 provided in an overlapped state around a hollow storing case 20c is joined in a body with rigidity in supporting by filling with a filling material. Then, the substantial thickness of the outer circumferential walls 20a2, and 20b2 is greatly increased to enhance the rigidity so that the roundness of the outer circumferential walls 20a2, and 20b2 is held with accuracy. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a motor automatic balancing apparatus configured to cancel out rotational imbalance of a rotating body.

[0002]

2. Description of the Related Art Generally, industrial machines, household appliances,
Alternatively, in a rotary drive device including a motor unit used in various devices such as a computer, an automatic balancing device is often employed in order to cancel the rotational imbalance of a rotating body including the rotary shaft of the motor unit. As the automatic balancing device, various structures have been proposed in the past. For example, in the device disclosed in Japanese Patent Laid-Open No. 10-257710, as shown in FIG.
An automatic balancer A including a hollow annular storage case body 3 is attached to a rotary shaft 2 which is an output shaft of
A plurality of balance spheres 4, 4, ... Are accommodated in the hollow annular storage case body 3 provided in the automatic balancing device A so as to be freely movable.

Each of these balancing spheres 4 is attracted to the outer peripheral surface of the holding magnet 5 arranged in the central portion in the radial direction of the hollow annular case 3 when the motor unit 1 is rotating at a low speed including when the motor unit 1 is started. And is held, and when the rotation speed of the motor unit 1 exceeds the resonance rotation speed CR,
It begins to separate from the holding magnet 5 outward in the radial direction. Then, each of the balancing spheres 4 moves in a direction opposite to the position of the center of gravity of the rotating body including the rotating shaft 2 and the automatic balancing device A, that is, to a position that cancels the rotational imbalance of the rotating body. By performing the balancing action that balances the rotation of the rotating body and performing the balancing action by the balance sphere 4, the vibration of the rotating body is reduced and the rotation state is stabilized. It has become.

At this time, the hollow storage case body 3 generally has a structure in which it is split in two in the axial direction, and the two hollow annular members 3a and 3b formed in a substantially cup shape are It is configured by being fitted in the axial direction, and has a double wall structure so that foreign matter and the like does not enter from the outside. Then, the plurality of balance spheres 4 described above are inserted into the inner side in a state in which the hollow storage case body 3 is opened at a stage before the two hollow annular members 3a and 3b are fitted to each other, After that, the both hollow annular members 3
The a and the 3b are axially opposed to each other and fitted.

Further, on the outer peripheral portion of the hollow housing case body 3, there are arranged two outer peripheral standing wall portions 3a1 and 3b1 respectively provided on the outer peripheral sides of the two hollow annular members 3a and 3b. Two outer peripheral standing wall portions 3a1 and 3b
1 is superposed on each other so as to face each other. Then, the plurality of balance spheres 4 inserted into the hollow storage case body 3 described above are brought into contact with the outer peripheral standing wall portion 3a1 arranged inside of the outer peripheral standing wall portions 3a1 and 3b1 by centrifugal force. It is designed to be moved while.

[0006]

However, in order to perform the balancing action by moving the balance sphere 4 freely inside the hollow storage case body 3 with high accuracy, the respective balance spheres 4 are to be performed with high accuracy. Therefore, it is necessary to ensure the roundness of the structure supporting the balance sphere 4, in particular, the roundness of the outer peripheral standing wall portion 3a1 described above, with high accuracy. Therefore, when the two hollow annular members 3a and 3b described above are fitted in the axial direction, the outer peripheral wall portion 3a of the hollow annular members 3a and 3b is fitted.
It is necessary to avoid a situation in which 1,3b1 is deformed as much as possible. Therefore, a fitting means for generating a deformation stress to the outer peripheral standing wall portions 3a1, 3b1 such as press fitting or shrink fitting is adopted. I can't.

For this reason, the above-mentioned 2
Both outer peripheral standing wall portions 3a1, 3 of the hollow annular members 3a, 3b of the body
b1 and the outer peripheral wall portions 3a1, 3a1,
A narrow gap is defined in the radial direction between the 3b1s. However, if a gap is formed between the outer peripheral wall portions 3a1 and 3b1 of the two hollow annular members 3a and 3b in this manner, in particular, the balance spheres 4 described above are formed.
The supporting rigidity of the outer peripheral standing wall portion 3a1 directly contacting with each other decreases, and when the centrifugal speed is very high and a strong centrifugal force acts like a recent device, a strong contact pressure by each of the balance spheres 4 is exerted. By both outer wall 3
The a1 and 3b1 may be deformed so as to project outward. Then, this may hinder the free movement of the balance spheres 4 described above.

In such a case, the hollow annular member 3a,
The rigidity may be increased by increasing the plate thickness of the outer peripheral standing wall portions 3a1 and 3b1 of 3b. However, in recent devices, the outer diameter dimension and the plate thickness are often restricted due to the demand for downsizing, There is a limit to increasing the rigidity of the hollow annular members 3a and 3b themselves.

Therefore, the present invention provides an automatic balancing device for a motor, which is capable of smoothly moving the balancing sphere and accurately performing the balancing action with a simple structure without increasing the size of the device. The purpose is to do.

[0010]

In order to achieve the above object, in the motor automatic balancing apparatus according to the first aspect of the present invention, two hollow annular members are provided on the outer peripheral side of the hollow housing case body. The outer peripheral side standing wall portions are superposed so as to be close to the inside and outside with a narrow gap in the radial direction, and the two outer peripheral side standing wall portions are placed in the narrow gap between the two outer peripheral side standing wall portions. A filling material that interlocks the parts to enhance the support rigidity of the balance sphere against the contact pressure is interposed. According to the motor automatic balancing apparatus having such a configuration, the substantial wall thickness of each outer peripheral side standing wall portion of the two hollow annular members constituting the hollow housing case body is such that The filling material interposed in the narrow gap between the two significantly increases the rigidity, and the rigidity is increased accordingly, so that the roundness of the outer peripheral side standing wall portion is maintained with high accuracy. Therefore, the free movement of the balance sphere inserted inside the hollow storage case body is favorably ensured, and the balancing action by the balance sphere is performed with high accuracy.

Further, in the motor automatic balancing apparatus according to a second aspect, the two hollow annular members forming the hollow housing case body according to the first aspect are respectively formed so as to have a substantially cup shape. The two hollow annular members are arranged so that the substantially cup-shaped openings are axially opposed to each other, and the outer peripheral side standing wall portions of the two hollow annular members are substantially cup-shaped. Since each hollow annular member has a substantially cup shape, it can be easily manufactured.

Further, in the motor automatic balancing apparatus according to a third aspect of the present invention, the narrow gap between the standing wall portions of the two hollow annular members in the first aspect is opened to the outside, and the narrow gap is formed. A filler injection passage communicating with the inside is provided, and since the filler is injected from the filler injection passage toward the inside of the narrow gap using the capillary phenomenon, The filling material can be easily and accurately provided in the narrow gap.

Furthermore, in the motor automatic balancing apparatus according to a fourth aspect, the outer opening portion of the filler injection passage according to the third aspect is provided so that the passage cross-sectional area increases toward the outside of the motor. Since the filler is stored in the passage enlarged portion in an appropriate amount, the filler is hung down to the outer opening of the filler injection passage by a necessary amount. Only then, the filling material can be injected efficiently.

On the other hand, in the automatic balancing apparatus for a motor according to a fifth aspect, the narrow gap between the standing wall portions of the two hollow annular members in the third aspect communicates with the inside of the hollow storage case body. In addition, since the gap expanding portion for sealing the filler flowing from the narrow gap toward the hollow storage case body is provided, the filler injected into the narrow gap does not overflow into the hollow storage case body. It is well prevented with a simple structure, and the smooth free movement of the balance sphere is not hindered by the filler.

Further, in the motor automatic balancing apparatus according to claim 6, the length of the gap expanding portion in the axial direction extending in the axial direction is set to be shorter than the radius of the balance sphere. Therefore, the range where the outer peripheral side standing wall of the hollow annular member becomes thin due to the provision of the gap expansion portion does not reach the portion where the balance sphere abuts, and as a result, even if the gap expansion portion is provided, the balance sphere is provided. The support rigidity for the is not reduced.

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION 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
-The entire structure of the ROM or DVD drive unit will be described. That is, in the mechanical chassis 11 of the CD-ROM drive unit 10 shown in FIG. 1, a spindle motor unit 13 that rotationally drives a recording disk 12 and a laser beam is applied to the recording disk 12 to write or write information. Optical pickup device 14 for reading
Is mounted.

The recording disk 12 is mounted on a disk table (see reference numeral 139 in FIG. 2) attached to the rotary shaft of the spindle motor section 13, while the optical pickup device 14 is the mechanical chassis. A pair of parallel guide shafts 15 mounted on 11,
It is mounted so as to be capable of reciprocating with respect to 15, and a light beam emitted from a laser light source (not shown)
Irradiate the recording disk 12 through 6 and
It has a configuration for detecting the reflected light from the recording disk 12.

Further, as shown in FIG. 2, the spindle motor unit 13 is provided with a hollow cylindrical bearing holder 132 mounted so as to rise substantially vertically to the main body frame 131. The bearing member 133 is press-fitted inside the hollow interior of the bearing holder 132. The bearing member 133 has two bearing portions in the axial direction.
As the above, various types of bearing members such as oil-impregnated sliding bearings, bearing bearings, metal bearings, and dynamic pressure bearing devices can be adopted.

A rotary shaft 134 is rotatably supported at the central portion of the bearing holder 132 via the bearing member 133, and the bearing holder 132 is also provided.
A stator core 135 made of a laminated body of silicon steel plates or the like is fitted on the peripheral wall surface on the outer peripheral side. An insulating layer is formed by coating on the surface of the stator core 135, and the coil winding 136 is wound around each salient pole portion of the stator core 135 via the insulating layer.

Further, at a position directly above the bearing holder 132 in FIG. 2, a central portion of a substantially cup-shaped rotor case 137 formed in a substantially hollow cylindrical shape is fixed to the rotary shaft 134 by press fitting or the like. An annular peripheral wall portion 137 provided on the outer peripheral portion of the rotor case 137.
A ring-shaped rotor magnet 138 is fixed to the inner peripheral surface side of a. This rotor magnet 1
The inner peripheral surface of 38 is arranged so as to approach each salient pole portion of the stator core 135 described above from the radially outer side.

A disc table (turntable) 139 formed of a substantially disc-shaped resin material (PC) is fixed to the protruding portion of the rotary shaft 134 on the upper side in the drawing. The disc table 139 is fixed by press-fitting a rotary shaft press-fitting hole formed in the central portion into the rotary shaft 134, and a substantially conical shape formed in a convex shape from the fixed portion toward the upper side in the drawing. Positioning protrusion 1
By 39a, the recording disk mounted on the disk table 139 (see reference numeral 12 in FIG. 1) is held in a state of being positioned at a predetermined position. A ring-shaped chucking magnet 139b is formed on the top of the positioning protrusion 139a.
Are attached via a yoke plate 139c.

The chucking magnet 139b is
The recording disk 12 is arranged so as to be exposed upward from the center hole of the recording disk 12 held by the positioning protrusion 139a, and is provided on the side of a pressing member (not shown) used for the recording disk 12. The magnetic pressing ring is provided so as to be magnetically attracted and held.

An automatic balancing device 20 for balancing the rotation of the rotating body including the rotor case 137 and the rotating shaft 134 is attached at a position immediately below the disk table 139 in the axial direction. This automatic balancer 20
Has a function of canceling the rotational imbalance generated in the rotating body when the rotational speed of the motor unit 13 exceeds the resonance rotational speed CR of the rotating body, by a balancing action due to mass movement. , Above disk table 1
An upper hollow annular member 20a made of a resin material (PC) integral with 39 and a lower hollow annular member 20b made of a non-magnetic pressed product form a hollow storage case body 20c. ing.

The upper hollow annular member 20a and the lower hollow annular member 20b are both formed in a substantially cup shape that opens in the axial direction, and the upper hollow annular member is arranged on the upper side in the drawing. The lower hollow annular member 20b is fitted to the member 20a such that the openings face each other in the axial direction from the lower side in the drawing. And
A space for accommodating a balance sphere 20d described later is defined inside the hollow storage case body 20c formed thereby.

The hollow storage case body 20c thus formed is rotated integrally with the disk table 139, and as shown in FIG. Lower hollow annular member 20
In the outer peripheral portion and the inner peripheral portion in b, respectively, the inner peripheral side standing wall portions 20a1 and 20b1 and the outer peripheral side standing wall portions 20a2 extending concentrically in the axial direction (the vertical direction in the drawing), respectively.
20b2 is provided. These inner peripheral side wall portions 20
a1, 20b1 and outer peripheral side standing wall portions 20a2, 20b2
Are provided so as to rise in the axial direction substantially at right angles from the bottom wall portions 20a3, 20b3 extending in the radial direction with an appropriate radial distance.

At this time, the lower hollow annular member 20b
Between the inner peripheral side standing wall portion 20b1 and the outer peripheral side standing wall portion 20b2, the inner peripheral side standing wall portion 20a1 and the outer peripheral side standing wall portion 20a of the upper hollow annular member 20a.
2 is attached, and both the inner peripheral side standing wall portion 20a1 and the outer peripheral side standing wall portion 20a2 of the upper hollow annular member 20a are attached to the inner peripheral side standing wall portion 20b1 of the lower hollow annular member 20b.
It is arranged so as to be sandwiched in the radial direction by both the outer peripheral wall 20b2.

An annular space is defined at a portion corresponding to the distance between the inner peripheral side standing wall portion 20a1 and the outer peripheral side standing wall portion 20a2 of the upper hollow annular member 20a which are radially separated from each other. , The balance spheres 20d, 20 composed of a plurality of magnetic masses in the annular space.
d, ... Are accommodated so as to be freely movable in the circumferential direction and the radial direction. The balance sphere 20d will be described later.

Here, the above-mentioned upper hollow annular member 20
The outer peripheral standing wall 20a2 of a is arranged such that the outer peripheral standing wall 20b2 of the lower hollow annular member 20b is superposed without contact from the radially outer side. The parts 20a2 and 20b2 are superposed and arranged so as to face the inner and outer circumferences with a narrow gap S in the radial direction. The narrow gap S is provided so as not to press the two outer peripheral side standing wall portions 20a2, 20b2 into pressure contact with each other, and particularly, the upper hollow annular member 20a and the lower hollow annular member 20b are assembled. The roundness of the outer peripheral side standing wall portions 20a2, 20b2 is maintained by not pressing the press fitting state.

Then, the two superposed layers are arranged on the inner and outer circumferences.
In the narrow gap S defined between the two outer peripheral side wall portions 20a2, 20b2, a filler made of an adhesive or the like is interposed. This filler is used for both the outer peripheral side standing wall portions 2
0a2 and 20b2 are integrally connected to each other so as to increase the supporting rigidity of the balance sphere 20d against the contact pressure.
Is for supporting the outer peripheral side standing wall portion 20a2 of the upper hollow annular member 20a directly contacting with the outer peripheral side standing wall portion 20b2 of the lower hollow annular member 20b.

As the above-mentioned filling material, a material such as an adhesive which is solidified after flowing and pouring into the narrow gap S is adopted, and the two outer peripheral side standing wall portions 20a2 A filler injection passage Sa that communicates with the inner side of the narrow gap S is provided at a portion on the upper end side in the drawing where the narrow gap S between the 20b2 is open to the outside. Then, within the narrow gap S from the filling material injection passage Sa
Towards, the filler is configured to be injected by utilizing the capillary phenomenon in the narrow gap S.

The filler injection passage Sa has a flange portion 20a4 extending from the outer peripheral side standing wall portion 20a2 of the upper hollow annular member 20a so as to cover the outer peripheral side standing wall portion 20b2 of the lower hollow annular member 20b. Lower hollow annular member 20
It is defined so as to form a narrow bending space between the outer peripheral side standing wall portion 20b2 and the upper end edge portion in the figure of the drawing, and once extends outward in the radial direction from the upper end opening portion of the narrow gap S shown in the figure. After it is present, it bends at a substantially right angle and opens downward in the drawing.

At the outer opening of the filling material injection passage Sa, the above-mentioned upper hollow annular member 20a is formed.
The flange portion 20a4 of the inclined taper wall surface 20 expands the passage sectional area downward in the drawing toward the space outside the motor.
It is formed so as to form a5, and is configured such that the filler is stored in an appropriate amount in the enlarged passage portion defined by the inclined tapered wall surface 20a5.

The lower end portion of the narrow gap S shown in the drawing is
The annular space of the hollow storage case body 20c described above, that is, the outer peripheral side wall 20a2 of the upper hollow annular member 20a.
Although it is communicated with the inner side of the, the gap expansion portion Sb is provided at the communication site. The gap enlargement portion Sb is formed by cutting out a part of the lower end portion of the outer peripheral side standing wall portion 20a2 of the upper hollow annular member 20a shown in the figure from the outer side toward the inner side in the radial direction by an appropriate thickness. By providing the gap expanding portion Sb, the hollow storage case body 20c can be removed from the narrow gap S.
The filling material flowing toward the annular space is sealed.

At this time, the length h of the gap expanding portion Sb extending in the axial direction is set to a length slightly shorter than the radius r of the balance sphere 20d, and by providing the gap expanding portion Sb, The portion that directly supports the balance sphere 20d is configured so as not to become thin.

Thus, the two upper hollow annular members 2
0a and the lower hollow annular member 20b are made of different materials, for example, a highly accurate molding material is used on the inside where the balance sphere 20d comes into contact and a thin metal material having high rigidity is used on the outside. By designing and interposing a filler between them, a highly rigid and compact automatic balancing device 20 can be obtained.

On the other hand, the above-mentioned upper hollow annular member 20a
Inner peripheral side standing wall portion 20a1 and outer peripheral side standing wall portion 20a2 in
The balance spheres 20d, 20d, ... Arranged in the annular space defined between and are formed of a material having a minimum residual magnetism, for example, chrome steel (SUJ-2). Bottom wall portion 20b of the lower hollow annular member 20b
3, or along the bottom wall portion 20a3 of the upper hollow annular member 20a, is freely movable in the radial direction and the circumferential direction.

Each of the balance spheres 20d is configured to perform the balancing action of the rotating body including the rotor case 137, the rotating shaft 134 and the like described above. That is,
The rotation speed of the spindle motor unit 13 is an appropriate rotation speed that exceeds the resonance rotation speed CR of the rotating body and is in the direction opposite to the center of gravity of the rotating body, that is, the rotational unbalance of the rotating body is canceled. The mass is adjusted so as to move toward the radially outward position indicated by the chain double-dashed line in FIG. 2, thereby balancing the rotation of the rotating body and reducing the vibration of the rotating body. The rotation is stabilized while being controlled.

Further, the inner peripheral side standing wall portion 20b1 of the lower hollow annular member 20b is arranged further inside than the inner peripheral side standing wall portion 20a1 of the upper hollow annular member 20a closer to the center, and these Both inner peripheral side standing wall portions 20a1 and 20b
An appropriate space is defined between the ones. A ring-shaped holding magnet 20f that attracts the balance sphere 20d toward the center is installed in the space. The holding magnet 20f is magnetized in a single pole in the radial direction, and has the spindle motor unit 1
The balance spheres 20d, 20d, ... Are magnetically attracted during low-speed rotation until the rotational speed of 3 reaches an appropriate operating speed before exceeding the resonance rotational speed CR. , The balance spheres 20d, 20
.. are attracted to and held in contact with the above-mentioned inner peripheral side standing wall portion 20d and held in a fixed state.

The holding magnet 20f described above is
It is not always necessary to use, and a non-magnetic material is used as the balance sphere 20d when the holding magnet 20f is not used.

According to the motor automatic balancing apparatus 20 of this embodiment having such a configuration, the two upper hollow annular members 20 constituting the hollow storage case body 20c.
a and the outer peripheral side standing wall portions 20 of the lower hollow annular member 20b
Since the filler is interposed in the narrow gap S defined between the a2 and 20b2, the two upper hollow annular members 20 constituting the hollow storage case body 20c.
a and the outer peripheral side standing wall portions 20 of the lower hollow annular member 20b
The substantial wall thicknesses of a2 and 20b2 are such that
It is significantly increased by the filler interposed in the narrow gap S between the a2 and 20b2. Therefore, since the rigidity of both outer peripheral side standing wall portions 20a2, 20b2 is increased by the amount of the increased thickness, the roundness of the outer peripheral side standing wall portion 20a2 that directly supports the balance sphere 20d is highly accurate. As a result, the hollow storage case body 2 is maintained.
The free movement of the balance sphere 20d inserted on the inner side of 0c is favorably ensured, and the balancing action by the balance sphere 20d is performed with high accuracy.

In the motor automatic balancing apparatus according to this embodiment, the hollow storage case body 20c is formed.
Since the upper hollow toroidal member 20a and the lower hollow toroidal member 20b of the body are each formed to have a substantially cup shape, the upper hollow toroidal member 20a and the lower hollow toroidal member 20b are It is designed to be easily manufactured.

Further, in the motor automatic balancing apparatus according to the present embodiment, the outer peripheral standing wall portions 20a2, 20a of the two upper hollow annular members 20a and the lower hollow annular member 20b.
In the narrow gap S between the b2, the filler injection passage Sa
Since the filling material is injected by utilizing the capillary phenomenon, the filling material can be easily and accurately provided in the narrow gap S.

Furthermore, an outer opening portion of the filler injection passage Sa is provided so that the passage cross-sectional area increases toward the outside of the motor, and an appropriate amount of filler is stored in the passage enlarged portion. Since it is configured as described above, it is possible to efficiently inject the filler only by hanging the required amount of the filler from the outer opening portion of the filler injection passage Sa.

In addition, in this embodiment, the narrow gap S between the outer peripheral side standing wall portions 20a2, 20b2 of the two upper hollow annular members 20a and the lower hollow annular member 20b.
In addition, the gap expansion portion Sb that seals the filler flowing from the narrow gap S toward the inside of the hollow storage case body 20c.
Since the filler is provided, the protrusion of the filler injected into the narrow gap S into the hollow storage case body 20c is favorably prevented with a simple configuration, and the smooth free movement of the balance sphere 20d is prevented. It is designed to be unobtrusive.

In the motor automatic balancing apparatus according to this embodiment, the axial length h of the gap expanding portion Sb is set to be shorter than the radius r of the balance sphere 20d. Since the range in which the outer peripheral side standing wall portion 20a2 of the upper hollow annular member 20a is thinned by the provision of Sb does not reach the portion where the balance sphere 20d abuts, the gap expansion portion S is formed.
By providing b, the supporting rigidity of the balance sphere 20d is not reduced.

Although the embodiments of the invention made by the present inventor have been specifically described above, the present invention is not limited to the above-mentioned embodiments, and various modifications can be made without departing from the spirit of the invention. Needless to say.

For example, in the above-described embodiment, the gap expanding portion Sb for sealing the filling material is provided in the upper hollow annular member 20a.
Although it is provided at the lower end portion of the outer peripheral side standing wall portion 20a2 in the figure, the gap expanding portion Sb may be formed in a groove shape at an intermediate position in the length direction (the vertical direction in the figure) of the outer peripheral side standing wall portion 20a2. It is possible.

Further, the structure for forming the above-described gap widening portion Sb is not limited to the step shape, and as shown in the figure, it may be formed by an inclined surface such as a chamfered portion. It is possible.

Further, in the above-described embodiment, after the upper hollow annular member 20a and the lower hollow annular member 20b are assembled, the filler is placed in the narrow gap S between the outer peripheral side standing wall portions 20a2 and 20b2. Is injected, but the upper hollow annular member 20a and the lower hollow annular member 2
Before assembling with 0b, a filler such as an adhesive may be applied in advance on the surface of either one of the outer peripheral side standing wall portions 20a2, 20b2.

Further, the arrangement relationship between the outer peripheral side standing wall portions 20a2, 20b2 of the upper hollow annular member 20a and the lower hollow annular member 20b in the above-described embodiment, that is, the both outer peripheral side standing wall portions 20a2, 20b2. The present invention can be similarly applied to the case where the arrangement relationship between the inner and outer circumferences is reversed.

Further, it is desirable that the above-mentioned filling material is intervened over the entire circumference of the narrow gap S, but for example, both outer peripheral side standing wall portions 20a2 of the upper hollow annular member 20a and the lower hollow annular member 20b are formed. 20b2 between
It is also possible to fit them by weak press-fitting that does not cause deformation and interpose the fillers in the gaps created after the press-fitting so as to be scattered.

Further, the present invention can be similarly applied to a device other than the CD-ROM or DVD drive device as in the above-mentioned embodiment, and the applicable motor is a servo motor, an air motor, or the like. It can be applied to a wide variety of.

[0053]

As described above, according to the first aspect of the present invention, the motor automatic balancing device is provided in the narrow gap between the two outer peripheral side standing wall portions which are superposed on the outer peripheral side of the hollow storage case body. , The two outer peripheral side standing wall portions are integrally connected to each other, and a filling material that enhances the support rigidity against the contact pressure of the balance sphere is interposed to substantially increase the substantial wall thickness of the outer peripheral side standing wall portion of the hollow storage case body. By increasing the rigidity to improve the roundness of the outer peripheral side standing wall portion with high accuracy, the balance sphere inserted inside the hollow storage case body is well secured for free movement, and the balance is improved. Since the balancing operation by the sphere is configured to be performed with high accuracy, the balancing sphere can be smoothly moved freely and accurately with a simple configuration without increasing the size of the device. It can, while reducing the size of the automatic balancing device of the motor can be improved the balance correction function.

According to a second aspect of the present invention, there is provided an automatic balancing device for a motor, wherein the two hollow annular members constituting the hollow housing case body of the first aspect are each formed into a substantially cup shape. The two hollow annular members are arranged so that the substantially cup-shaped openings are axially opposed to each other, and the outer peripheral side standing wall portions of the two hollow annular members are substantially cup-shaped. Since each is provided on the outer peripheral side of the hollow annular member, the hollow annular member is easily manufactured.
In addition to the effects described above, productivity can be improved.

Further, in the motor automatic balancing apparatus according to a third aspect, the narrow gap between the standing wall portions of the two hollow annular members in the first aspect is opened to the outside, and the narrow gap is provided. A filler injection passage communicating with the inside is provided, and the filler is injected from the filler injection passage toward the inside of the narrow gap by utilizing a capillary phenomenon. Since the filler is easily and accurately provided in the narrow gap, it is possible to further improve the productivity in addition to the above-mentioned effects.

Furthermore, in the motor automatic balancing apparatus according to a fourth aspect, the outer opening portion of the filler injection passage according to the third aspect is provided such that the passage cross-sectional area increases toward the outside of the motor. Since the filling material is configured to be stored in an appropriate amount in the enlarged passage portion, the filling material is hung down to the outer opening portion of the filling material injection passage by a necessary amount. Since it is designed to efficiently inject the filling material,
In addition to the effects described above, productivity can be further improved.

On the other hand, in the automatic balancing apparatus for a motor according to a fifth aspect, the narrow gap between the standing wall portions of the two hollow annular members in the third aspect communicates with the inside of the hollow storage case body. In, by the provision of a gap expansion portion for sealing the filler flowing from the narrow gap into the hollow storage case body, the filler injected into the narrow gap does not overflow into the hollow storage case body. The simple structure is well prevented, and the smooth free movement of the balance sphere is not hindered by the filler, so that the balance correction function can be well maintained, and the above-mentioned effects can be obtained. You can definitely get it.

According to a sixth aspect of the present invention, there is provided an automatic motor balancing device, wherein the length of the gap expanding portion extending in the axial direction is set to be shorter than the radius of the balance sphere. Therefore, it is assumed that the area where the outer peripheral side standing wall portion of the hollow annular member becomes thin due to the provision of the gap expansion portion does not reach the portion where the balance sphere abuts. Therefore, the balance correction function can be more favorably maintained, and the above-described effect can be reliably obtained.

[Brief description of drawings]

FIG. 1 is a CD-R as an example of a device to which the present invention is applied.
It is an external perspective explanatory view showing an OM or DVD drive unit.

FIG. 2 is a vertical cross-sectional explanatory view showing an embodiment of a motor with an automatic balancing device adopted in the CD-ROM or DVD drive unit shown in FIG.

FIG. 3 is an explanatory longitudinal sectional view showing an enlarged main part of the automatic balancing apparatus for the motor shown in FIG.

FIG. 4 is a partially enlarged vertical cross-sectional explanatory view showing another embodiment of the gap widening portion.

FIG. 5 is a vertical cross-sectional explanatory view showing a structural example of a rotary drive device including a general automatic balancing device.

[Explanation of symbols] 10 CD-ROM drive unit 12 recording discs 13 Spindle motor section 137 rotor case 138 rotor magnet 139 Disc table (turntable) 134 rotation axis 20 Automatic balancing device 20a Upper hollow annular member 20b Lower hollow annular member 20c hollow storage case body 20a1, 20b1 inner peripheral standing wall 20a2, 20b2 outer peripheral side standing wall portion 20a3, 20b3 bottom wall 20d balance sphere S Narrow gap (filler) Sa filler injection passage 20a4 flange 20a5 Inclined taper wall surface (enlarged passage) Sb gap expansion part

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Claims (6)

[Claims] 1. A structure for canceling a rotational imbalance by a balancing action when a rotational speed of a motor unit for driving a rotating body exceeds a resonance rotational speed of the rotating body, the axial unbalance A plurality of balance spheres are movably housed inside a hollow housing case body composed of two fitted hollow annular members, and the balance spheres are moved to a position where the rotational unbalance of the rotating body is canceled. In an automatic balancing device for a motor that performs the balancing action by moving while contacting the outer peripheral wall of a hollow storage case body, the two hollow annular members are provided on the outer peripheral side of the hollow storage case body. The two outer peripheral side standing wall portions respectively provided are overlapped so as to be close to the inside and the outside with a small gap in the radial direction, and the two outer peripheral side standing wall portions and the like are arranged. The teeth in the narrow gap between the,
An automatic balancing device for a motor, characterized in that a filling material for interposing the two outer peripheral side standing wall portions so as to be integrated so as to enhance the support rigidity against the contact pressure of the balance sphere is interposed. 2. The structure 2 which constitutes the hollow storage case body.
The hollow annular members of the body are respectively formed to have a substantially cup shape, and the hollow annular members of the two bodies are arranged such that the substantially cup-shaped openings are axially opposed to each other. The automatic balancing device for a motor according to claim 1, wherein each of the outer peripheral side standing wall portions of the two hollow annular members is provided on the outer peripheral portion side of the substantially cup shape. 3. A filler injection passage communicating with the inner side of the narrow gap is provided at a portion where the narrow gap between the standing wall portions of the two hollow annular members opens to the outside, The automatic balancing apparatus for a motor according to claim 1, wherein the filler is injected from the filler injection passage toward the inside of the narrow gap by utilizing a capillary phenomenon. 4. An outer opening portion of the filling material injection passage is provided so that a passage cross-sectional area increases toward the outside of the motor, and the filling material is stored in an appropriate amount in the passage expansion portion. The automatic balancing device for a motor according to claim 3, wherein the automatic balancing device is configured as follows. 5. A narrow gap between the standing wall portions of the two hollow annular members flows into the hollow storage case body from the narrow gap to a portion communicating with the inner side of the hollow storage case body. The automatic balancing device for a motor according to claim 3, wherein a gap widening portion for sealing the filling material is provided. 6. The automatic balancing device for a motor according to claim 4, wherein a length of the gap expanding portion extending in the axial direction is set to be shorter than a radius of the balance sphere.