JP3896470B2 - Automatic motor balancing device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a motor automatic balancing device configured to cancel a rotational imbalance of a rotating body.
[0002]
[Prior art]
In general, a rotational drive device including a motor unit used in various devices such as industrial machines, household appliances, or computers is used to cancel the rotational imbalance of a rotating body including the rotation shaft of the motor unit. Automatic balancing devices are often employed. As the automatic balancing device, devices having various structures have been conventionally proposed. For example, in the device described in Japanese Patent Application Laid-Open No. 10-257710, as shown in FIG. An automatic balancing device A including a hollow annular storage case body 3 is attached to the rotary shaft 2 that is the output shaft of the hollow annular storage case body 3 provided in the automatic balancing device A. A plurality of balance spheres 4, 4,... Are accommodated therein so as to be freely movable.
[0003]
Each of the balance spheres 4 is attracted and held by the outer peripheral surface of the holding magnet 5 disposed at the center portion in the radial direction of the hollow annular case 3 when the motor unit 1 is rotated at a low speed including when the motor unit 1 is started. Thus, when the rotational speed of the motor unit 1 exceeds the resonant rotational speed CR, the motor unit 1 starts to detach from the holding magnet 5 outward in the radial direction. Each of the balance spheres 4 moves to a direction opposite to the center of gravity of the rotating body including the rotating shaft 2 and the automatic balancing device A, that is, a position that cancels the rotational unbalance of the rotating body. The balancing action for balancing the rotation of the rotating body is performed, and the balancing action by the balancing sphere 4 is performed, so that the vibration of the rotating body is reduced and the rotation state is stabilized. It has become.
[0004]
At this time, the hollow storage case body 3 is generally divided into two parts in the axial direction, and the two hollow annular members 3a and 3b formed in a substantially cup shape are connected in the axial direction. It is configured by being fitted, and has a double wall structure so that foreign matter or the like does not enter from the outside. 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 in a stage before the two hollow annular members 3a and 3b are fitted together. Thereafter, the hollow annular members 3a and 3b are fitted to each other so as to face each other in the axial direction.
[0005]
Further, two outer peripheral standing wall portions 3a1 and 3b1 provided on the outer peripheral side of the two hollow annular members 3a and 3b are arranged on the outer peripheral portion of the hollow storage case body 3, respectively. The standing wall portions 3a1 and 3b1 are superposed so as to face the inner and outer peripheries. A plurality of balance spheres 4 inserted into the hollow housing case 3 described above are brought into contact with the outer peripheral standing wall 3a1 disposed inside the outer peripheral standing walls 3a1 and 3b1 by centrifugal force. While being moved.
[0006]
[Problems to be solved by the invention]
However, in order to perform the balancing action by freely moving the balance sphere 4 within the hollow storage case body 3 with high accuracy, it is necessary to move each of the balance spheres 4 very smoothly. Therefore, it is necessary to accurately ensure the roundness of the structure for supporting the balance sphere 4, in particular, the outer peripheral standing wall 3 a 1 described above. Therefore, in fitting the two hollow annular members 3a and 3b in the axial direction, it is necessary to avoid as much as possible the situation in which the outer peripheral standing wall portions 3a1 and 3b1 of the hollow annular members 3a and 3b are deformed. Therefore, it is not possible to employ fitting means that generates deformation stress on the outer peripheral standing wall portions 3a1 and 3b1, such as press fitting and shrink fitting.
[0007]
For this reason, conventionally, the outer peripheral standing wall portions 3a1 and 3b1 of the two hollow annular members 3a and 3b described above are fitted in a non-contact state while being slightly separated from each other in the radial direction. A narrow gap in the radial direction is defined between the outer peripheral standing wall portions 3a1 and 3b1. However, when a gap is formed between the outer peripheral standing wall portions 3a1 and 3b1 of the two hollow annular members 3a and 3b, the outer peripheral standing wall portion 3a1 in which the balance spheres 4 are in direct contact with each other. When the rotational speed is very high and a strong centrifugal force is applied as in recent equipment, the outer peripheral standing wall portions 3a1 and 3b1 are separated from each other by the strong contact pressure by the balance spheres 4. It may be deformed by projecting toward the side. As a result, the free movement of each of the balance spheres 4 may be hindered.
[0008]
In such a case, the rigidity may be increased by increasing the plate thickness of the outer peripheral standing wall portions 3a1 and 3b1 of the hollow annular members 3a and 3b. The plate thickness is often regulated, and there is a limit to increasing the rigidity of the hollow annular members 3a and 3b themselves.
[0009]
Accordingly, the present invention provides an automatic balancing device for a motor that can smoothly and freely move a balancing sphere with a simple configuration without increasing the size of the device and can perform a balancing operation with high accuracy. Objective.
[0010]
[Means for Solving the Problems]
In order to achieve the above object, in the automatic balancing device for a motor according to claim 1, two outer peripheral side standing wall portions respectively provided in the two hollow annular members are provided in the radial direction on the outer peripheral side of the hollow storage case body. It is arranged so as to be close to the inside and outside with a narrow gap, and the two outer peripheral side standing wall portions are connected so as to be integrated in the narrow gap between the two outer peripheral side standing wall portions. In addition, a filler for increasing the support rigidity against the contact pressure of the balance sphere is interposed.
According to the motor automatic balancing device having such a configuration, the substantial thickness of the outer peripheral side standing wall portions of the two hollow annular members constituting the hollow storage case body is such that the outer peripheral side standing wall portions are in contact with each other. Since the rigidity is greatly increased by the filler interposed in the narrow gap between the two, 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 ensured satisfactorily, and the balancing action by the balance sphere is performed with high accuracy.
[0011]
In the motor automatic balancing device according to claim 2, the two hollow annular members constituting the hollow storage case body according to claim 1 are formed so as to form a substantially cup shape, respectively, and the substantially cup shape. The two hollow annular members are disposed so that the openings of the two annular members are opposed to each other in the axial direction, and the outer peripheral side standing wall portions of the two hollow annular members are the substantially cup-shaped outer peripheral portions. Since each hollow annular member has a substantially cup shape, it is easily manufactured.
[0012]
Further, in the motor automatic balancing device according to claim 3, the narrow gap between the standing wall portions of the two hollow annular members according to claim 1 is formed at a position where the narrow gap is opened to the outside, A communicating filler injection passage is provided, and the filler is injected from the filler injection passage toward the inside of the narrow gap using a capillary phenomenon. On the other hand, the filler is provided easily and accurately.
[0013]
Furthermore, in the motor automatic balancing apparatus according to claim 4, the outer side opening portion of the filler injection passage in claim 3 is provided so that the passage cross-sectional area increases toward the outside of the motor. Since it is configured so that the filler is stored over an appropriate amount in the enlarged portion, it is only necessary to hang the filler by the necessary amount with respect to the outer opening portion of the filler injection passage. The filling material will be injected efficiently.
[0014]
On the other hand, in the motor automatic balancing apparatus according to claim 5, the narrow gap between the standing wall portions of the two hollow annular members in claim 3 is connected to the portion communicating with the inner side of the hollow storage case body. Since the gap expansion part is provided to seal the filler that flows from the narrow gap into the hollow storage case, the structure allows easy filling of the filler injected into the narrow gap into the hollow storage case. And the smooth free movement of the balance sphere is not hindered by the filler.
[0015]
Further, in the motor automatic balancing device according to claim 6, since the length of the gap expanding portion in claim 4 extending in the axial direction is set to be shorter than the radius of the balance sphere, The range in which the outer peripheral side standing wall portion of the hollow annular member becomes thin due to the provision of the enlarged portion does not reach the portion where the balance sphere abuts, and as a result, the support rigidity to the balance sphere even if the gap enlarged portion is provided Will not be reduced.
[0016]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
First, the overall structure of a CD-ROM or DVD drive unit to which the present invention is applied will be described. Specifically, the mechanical chassis 11 of the CD-ROM drive unit 10 shown in FIG. 1 has a spindle motor unit 13 that rotationally drives the recording disk 12, and a laser beam applied to the recording disk 12 to write information or An optical pickup device 14 for reading is mounted.
[0017]
The recording disk 12 is mounted on a disk table (see reference numeral 139 in FIG. 2) attached to the rotation shaft of the spindle motor unit 13, while the optical pickup device 14 is attached to the mechanical chassis 11. A pair of parallel guide shafts 15, 15 is mounted so as to be reciprocally movable, and 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 recording is performed. It has a configuration for detecting reflected light from the disk 12.
[0018]
Further, as shown in FIG. 2, the spindle motor unit 13 has a hollow cylindrical bearing holder 132 attached to the main body frame 131 so as to rise substantially vertically. A bearing member 133 is press-fitted on the hollow inner side of the bearing holder 132. The bearing member 133 includes two bearing portions in the axial direction. As the bearing member 133, various types of bearing members such as an oil-impregnated sliding bearing, a bearing bearing, a metal bearing, or a hydrodynamic bearing device are used. Can be adopted.
[0019]
A rotating shaft 134 is rotatably supported at the center portion of the bearing holder 132 via the bearing member 133, and a silicon steel plate or the like is provided on the outer peripheral wall surface of the bearing holder 132. A stator core 135 made of a laminated body is fitted. An insulating layer is formed on the surface of the stator core 135 by painting, and the coil winding 136 is wound around each salient pole portion of the stator core 135 via the insulating layer.
[0020]
Further, at the position directly above the bearing holder 132 in FIG. 2, the center portion of the substantially cup-shaped rotor case 137 formed in a substantially hollow cylindrical shape is fixed to the rotating shaft 134 by press-fitting or the like. A ring-shaped rotor magnet 138 is fixed to the inner peripheral surface side of the annular peripheral wall portion 137a provided on the outer peripheral portion of 137. The inner peripheral surface of the rotor magnet 138 is disposed so as to approach the salient pole portions of the stator core 135 described above from the radially outer side.
[0021]
Further, a disk table (turn table) 139 made of a substantially disk-shaped resin material (PC) is fixed to a protruding portion on the upper side of the rotating shaft 134 in the figure. The disk table 139 is fixed by press-fitting a rotary shaft press-fitting hole formed in the center portion into the rotary shaft 134, and has a substantially conical shape formed in a convex shape from the fixed portion toward the upper side in the figure. The recording disc (see reference numeral 12 in FIG. 1) mounted on the disc table 139 is held in a state of being positioned at a predetermined position by the positioning projection 139a. A chucking magnet 139b formed in a ring plate shape is attached to the top of the positioning projection 139a via a yoke plate 139c.
[0022]
The chucking magnet 139b is arranged so as to be exposed upward from the center hole of the recording disk 12 held by the positioning protrusion 139a described above, and is a pressing member (illustrated) used for the recording disk 12. The magnetic pressing ring provided on the (omitted) side is provided so as to be magnetically attracted and held.
[0023]
In addition, an automatic balancing device 20 for balancing the rotation of the rotating body including the rotor case 137 and the rotating shaft 134 described above is attached to a position directly below the disk table 139 in the axial direction. The automatic balancing device 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 accompanying mass movement. The upper hollow annular member 20a formed of a resin material (PC) integrated with the disk table 139, and the lower hollow annular member 20b formed of a non-magnetic material press product or the like. A hollow storage case body 20c is configured.
[0024]
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 20a disposed on the upper side in the drawing is formed on the upper hollow annular member 20a. On the other hand, the lower hollow annular member 20b is fitted so that the openings face each other in the axial direction from the lower side in the figure. And the space for accommodating the balance spherical body 20d mentioned later is defined in the inside of the hollow storage case body 20c formed by it.
[0025]
The hollow storage case body 20c formed in this way is rotated integrally with the disk table 139. In particular, as shown in FIG. 3, the upper hollow annular member 20a and the lower hollow member 20a described above are rotated. Inner circumferential side standing wall portions 20a1 and 20b1 and outer circumferential side standing wall portions 20a2 and 20b2 extending in the axial direction (vertical direction in the figure) in a concentric ring shape are respectively provided on the outer circumferential portion and the inner circumferential portion of the annular member 20b. Is provided. The inner peripheral side standing wall portions 20a1 and 20b1 and the outer peripheral side standing wall portions 20a2 and 20b2 stand up from the bottom wall portions 20a3 and 20b3 extending in the radial direction in the axial direction at a substantially right angle with an appropriate radial distance therebetween. Is provided.
[0026]
At this time, a region on the inner side of the lower hollow annular member 20b, that is, an inner peripheral side standing wall portion 20a1 of the upper hollow annular member 20a between the inner peripheral side standing wall portion 20b1 and the outer peripheral side standing wall portion 20b2. And the outer peripheral side standing wall 20a2 are mounted, and both the inner peripheral side vertical wall 20a1 and the outer peripheral side vertical wall 20a2 of the upper hollow annular member 20a are connected to the inner peripheral side vertical wall 20b1 of the lower hollow annular member 20b. And it is arrange | positioned so that it may be inserted | pinched by the radial direction by both the outer peripheral side standing wall part 20b2.
[0027]
An annular space is defined in a portion corresponding to a distance in which 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 separated in the radial direction. In the annular space, balance spheres 20d, 20d,... Made up of a plurality of mass bodies having magnetism are accommodated so as to be freely movable in the circumferential direction and the radial direction. The balance sphere 20d will be described later.
[0028]
Here, with respect to the outer peripheral side standing wall portion 20a2 of the upper hollow annular member 20a described above, the outer peripheral side standing wall portion 20b2 of the lower hollow annular member 20b is arranged to be polymerized in a non-contact manner from the radially outer side. These two outer peripheral side standing wall portions 20a2 and 20b2 are superposed and arranged so as to face the inner and outer periphery with a gap S narrow in the radial direction interposed therebetween. The narrow gap S is for disposing the two outer peripheral side standing wall portions 20a2 and 20b2 so as not to come into pressure contact with each other. In particular, the assembly of the upper hollow annular member 20a and the lower hollow annular member 20b is performed. The roundness of both the outer peripheral side standing wall portions 20a2 and 20b2 is maintained by not pressing in time.
[0029]
Then, a filler made of an adhesive or the like is interposed in the narrow gap S defined between the two outer peripheral side standing wall portions 20a2 and 20b2 that are superposed on the inner and outer peripheries. This filler is provided so as to increase the supporting rigidity against the contact pressure of the balance sphere 20d by connecting the outer peripheral side standing wall portions 20a2 and 20b2 so as to be integrated, and in particular, the balance sphere 20d. The outer peripheral side standing wall portion 20a2 of the upper hollow annular member 20a that directly contacts is supported by the outer peripheral side standing wall portion 20b2 of the lower hollow annular member 20b.
[0030]
As the filler, a material that is solidified after being poured into the narrow gap S, such as an adhesive, is used, but the two outer peripheral side standing wall portions 20a2 and 20b2 are used. A filler injection passage Sa communicating with the inner side of the narrow gap S is provided at a portion on the upper end side in the figure where the narrow gap S is opened to the outside. And it is comprised so that the said filler may be inject | poured toward the inside of the narrow gap S from the filler injection channel | path Sa using the capillary phenomenon of the said inside S of a narrow gap.
[0031]
The filler injection passage Sa includes 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, and a lower hollow portion It is defined so as to form a narrow bending space with the upper end edge of the annular member 20b on the outer peripheral side standing wall 20b2, and once outside the upper end opening of the narrow gap S in the radial direction. After extending in the direction, it bends at a substantially right angle and opens downward in the figure.
[0032]
In the outer opening portion of the filler injection passage Sa, the flange portion 20a4 of the upper hollow annular member 20a described above is an inclined taper that enlarges the passage sectional area toward the lower side of the drawing toward the space outside the motor. It is formed so as to form a wall surface 20a5, and is configured such that the filler is stored over an appropriate amount in a passage expanding portion defined by the inclined tapered wall surface 20a5.
[0033]
The illustrated lower end portion of the narrow gap S communicates with the annular space of the hollow storage case body 20c described above, that is, the inner side of the outer peripheral side wall 20a2 of the upper hollow annular member 20a. The part is provided with a gap enlarged portion Sb. The gap expanding portion Sb is formed by cutting out a part of the lower end portion in the figure of the outer peripheral side standing wall portion 20a2 of the upper hollow annular member 20a so as to cut out an appropriate thickness from the outer side toward the inner side in the radial direction. Since the gap expanding portion Sb is provided, the filler that flows from the narrow gap S toward the annular space of the hollow storage case body 20c is sealed. Yes.
[0034]
At this time, the length h in which the gap enlarged portion Sb extends in the axial direction is set to be slightly shorter than the radius r of the balance sphere 20d, and the balance sphere 20d is provided by providing the gap enlarged portion Sb. It is comprised so that the site | part which directly supports may not become thin shape.
[0035]
In this way, by using different materials as the two upper hollow annular members 20a and the lower hollow annular member 20b, for example, a highly accurate molding material is employed on the inner side where the balance sphere 20d contacts, By thinning the outer side with a metal material having high rigidity and interposing a filler between them, a high-rigidity and small-sized automatic balancing device 20 can be obtained.
[0036]
On the other hand, the balance spheres 20d, 20d,... Arranged in an annular space defined between the inner peripheral side standing wall portion 20a1 and the outer peripheral side standing wall portion 20a2 in the above-described upper hollow annular member 20a are as follows. , Formed of a material having as little residual magnetism as possible, for example, chrome steel (SUJ-2), on the bottom wall portion 20b3 of the lower hollow annular member 20b or the bottom wall portion 20a3 of the upper hollow annular member 20a. Along the radial direction and the circumferential direction, the free movement is possible.
[0037]
Each of these balance spheres 20d is configured to perform the balancing action of the rotating body including the rotor case 137 and the rotating shaft 134 described above.
That is, the rotational speed of the spindle motor unit 13 is an appropriate rotational speed exceeding the resonance rotational speed CR of the rotating body, and in the direction opposite to the center of gravity of the rotating body, that is, the rotational unbalance of the rotating body. The mass adjustment is made so as to move toward the radially outward position indicated by the two-dot chain line in FIG. 2, thereby counteracting the rotational balance of the rotating body, and the vibration of the rotating body. The rotation can be stabilized while reducing the above.
[0038]
Further, the inner peripheral side standing wall portion 20b1 of the lower hollow annular member 20b is disposed on the inner side closer to the center than the inner peripheral side standing wall portion 20a1 of the upper hollow annular member 20a. An appropriate space is defined between the side standing wall portions 20a1 and 20b1. A ring-shaped holding magnet 20f that attracts the balance sphere 20d toward the center is mounted in the space. The holding magnet 20f is magnetized in a single direction in the radial direction, and at the time of low-speed rotation until the rotational speed of the spindle motor unit 13 reaches an appropriate working rotational speed before exceeding the resonant rotational speed CR. The balance spheres 20d, 20d,... Are magnetically attracted, and the balance spheres 20d, 20d,... Are drawn onto the inner peripheral side standing wall 20d. It is made the structure kept in the fixed state which contacted.
[0039]
The holding magnet 20f described above is not necessarily used, and a nonmagnetic material is used as the balance sphere 20d when the holding magnet 20f is not used.
[0040]
According to the motor automatic balancing device 20 according to the present embodiment having such a configuration, both of the upper hollow annular member 20a and the lower hollow annular member 20b constituting the hollow storage case body 20c. Since the filler is interposed in the narrow gap S defined between the outer peripheral standing wall portions 20a2 and 20b2, the two upper hollow annular members 20a constituting the hollow storage case body 20c. And the substantial thickness of both outer peripheral side standing wall parts 20a2 and 20b2 of the lower hollow annular member 20b is greatly increased by the filler interposed in the narrow gap S between the outer peripheral side standing wall parts 20a2 and 20b2. Enhanced. Therefore, since the rigidity of both outer peripheral side standing wall portions 20a2 and 20b2 is increased by the increased thickness, the roundness of the outer peripheral side standing wall portion 20a2 that directly supports the balance sphere 20d is particularly highly accurate. As a result, the free movement of the balance sphere 20d inserted inside the hollow storage case body 20c is ensured satisfactorily, and the balancing action by the balance sphere 20d is performed with high accuracy. ing.
[0041]
Further, in the motor automatic balancing apparatus according to the present embodiment, the two upper hollow annular members 20a and the lower hollow annular member 20b constituting the hollow storage case body 20c are substantially cup-shaped, respectively. Since they are formed, the upper hollow annular member 20a and the lower hollow annular member 20b are easily manufactured.
[0042]
Furthermore, in the motor automatic balancing apparatus according to the present embodiment, the narrow gap S between the outer peripheral side standing wall portions 20a2 and 20b2 of the two upper hollow annular members 20a and the lower hollow annular member 20b is filled. Since the filler is injected from the material injection passage Sa using the capillary phenomenon, the filler is easily and accurately provided in the narrow gap S.
[0043]
Furthermore, the outer opening portion of the filler injection passage Sa is provided so that the cross-sectional area of the passage increases toward the outside of the motor, and the filler is stored in an appropriate amount in the passage enlarged portion. Since it is configured, the filler can be injected efficiently only by dropping a necessary amount of the filler from the outer opening of the filler injection passage Sa.
[0044]
In addition, in this embodiment, a hollow storage case is formed from the narrow gap S to the narrow gap S between the outer peripheral side standing wall portions 20a2 and 20b2 of the two upper hollow annular members 20a and 20b. Since the gap enlarged portion Sb for sealing the filler that flows toward the inside of the body 20c is provided, the protrusion of the filler injected into the narrow gap S into the hollow storage case body 20c, The simple configuration is well prevented and the smooth free movement of the balance sphere 20d is not hindered by the filler.
[0045]
Further, in the motor automatic balancing apparatus according to the present embodiment, since the axial length h of the gap expanding portion Sb is set to be shorter than the radius r of the balance sphere 20d, the gap expanding portion Sb is provided. Since the range in which the outer peripheral side standing wall portion 20a2 of the upper hollow annular member 20a is thinned is not reached by the portion where the balance sphere 20d abuts, the gap enlarged portion Sb is provided. Thus, the support rigidity of the balance sphere 20d is not lowered.
[0046]
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-described embodiments, and various modifications can be made without departing from the scope of the invention. Not too long.
[0047]
For example, in the above-described embodiment, the gap expanding portion Sb for sealing the filler is provided at the lower end portion in the drawing of the outer peripheral side standing wall portion 20a2 of the upper hollow annular member 20a, but the length of the outer peripheral side standing wall portion 20a2 is long. It is also possible to provide the gap enlarged portion Sb in a groove shape at a midpoint in the vertical direction (the vertical direction in the figure).
[0048]
Moreover, the structure which forms the said clearance expansion part Sb is not limited to a step shape, As shown in the figure, it is also possible to comprise by an inclined surface like a chamfer. .
[0049]
Further, in the above-described embodiment, after assembling the upper hollow annular member 20a and the lower hollow annular member 20b, the filler is injected into the narrow gap S between the outer peripheral side standing wall portions 20a2 and 20b2. However, before assembling the upper hollow annular member 20a and the lower hollow annular member 20b, an adhesive or the like is formed on the surface of either one of the outer peripheral side standing wall portions 20a2 and 20b2. A filler may be applied in advance.
[0050]
Further, in the above-described embodiment, the arrangement relationship between the outer peripheral side standing wall portions 20a2 and 20b2 of the upper hollow annular member 20a and the lower hollow annular member 20b, that is, the inner and outer peripheries of the outer peripheral side standing wall portions 20a2 and 20b2. The present invention can be similarly applied to a case where the arrangement relationship is reversed.
[0051]
Furthermore, it is desirable that the above-mentioned filler is interposed over the entire circumference of the narrow gap S. For example, both the outer peripheral side standing wall portions 20a2 and 20b2 of the upper hollow annular member 20a and the lower hollow annular member 20b are disposed. It is also possible to interpose with a press-fit that is weak enough not to cause deformation, and to interpose the filler in the gap generated after the press-fit.
[0052]
Furthermore, the present invention can be used in the same way for devices other than the CD-ROM or DVD drive device as in the above-described embodiment, and various motors such as a servo motor and an air motor can be applied. Can be applied to.
[0053]
【The invention's effect】
As described above, the automatic balancing device for a motor according to the first aspect of the present invention includes the two outer peripheries in the narrow gap between the two outer peripheral side standing wall portions that are arranged on the outer peripheral side of the hollow storage case body. The side wall is connected so as to be integrated, and a filler that increases the support rigidity against the contact pressure of the balance sphere is interposed, so that the substantial thickness of the outer wall on the outer periphery of the hollow storage case is greatly increased. By improving, the roundness of the outer peripheral side wall is maintained with high accuracy, the free movement of the balance sphere inserted inside the hollow storage case body is ensured, and the balancing action by the balance sphere is achieved. Therefore, the balance sphere can be moved smoothly and freely with a simple structure without increasing the size of the apparatus, and the balancing operation can be performed with high accuracy. While reducing the size of the automatic balancing device can be improved the balance correction function.
[0054]
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 storage case body of the first aspect are formed so as to form a substantially cup shape. The two hollow annular members are disposed so that the openings of the two annular members are opposed to each other in the axial direction, and the outer peripheral side standing wall portions of the two hollow annular members are the substantially cup-shaped outer peripheral portions. Since the hollow annular member is easily manufactured by being provided on each side, productivity can be improved in addition to the above-described effects.
[0055]
Further, in the motor automatic balancing device according to claim 3, the narrow gap between the standing wall portions of the two hollow annular members according to claim 1 is formed at a portion where the narrow gap is opened to the outside, A communicating filler injection passage is provided, and the filler is injected into the narrow gap from the filler injection passage toward the inside of the narrow gap. On the other hand, since the filler is provided easily and accurately, the productivity can be further improved in addition to the effects described above.
[0056]
Furthermore, the motor automatic balancing apparatus according to claim 4 is provided such that the outer side opening portion of the filler injection passage in claim 3 is provided so that the passage cross-sectional area increases toward the outside of the motor. By being configured so that the filler is stored over an appropriate amount in the enlarged portion, only a necessary amount of the filler is hung from the outer opening portion of the filler injection passage, Since the filling material is injected efficiently, productivity can be further improved in addition to the above-described effects.
[0057]
On the other hand, in the motor automatic balancing device according to claim 5, the narrow gap between the standing wall portions of the two hollow annular members according to claim 3 is connected to the portion communicating with the inner side of the hollow storage case body. A structure in which the filler injected into the narrow gap is easily protruded into the hollow storage case by providing a gap expanding portion that seals the filler flowing into the hollow storage case from the narrow gap. Since the smooth free movement of the balance sphere is not hindered by the filler, the balance correction function can be maintained well, and the above-described effects can be reliably obtained. be able to.
[0058]
Further, in the automatic balancing device for a motor according to claim 6, the length in which the gap expanding portion in claim 4 extends in the axial direction is set to be shorter than the radius of the balance sphere, By providing the gap expanding portion, the range where the outer peripheral side standing wall portion of the hollow annular member is in a thin state does not reach the part where the balance sphere abuts, and even if the gap expanding portion is provided, the support rigidity to the balance sphere is reduced. Therefore, the balance correction function can be maintained more satisfactorily, and the above-described effects can be reliably obtained.
[Brief description of the drawings]
FIG. 1 is an external perspective view showing a CD-ROM or DVD drive unit as an example of an apparatus to which the present invention is applied.
2 is a longitudinal cross-sectional explanatory view showing an embodiment of a motor with an automatic balancing device employed in the CD-ROM or DVD drive unit shown in FIG. 1. FIG.
FIG. 3 is an explanatory longitudinal sectional view showing an enlarged main part of the motor automatic balancing apparatus shown in FIG. 2;
FIG. 4 is a partially enlarged longitudinal sectional view illustrating another embodiment of a gap enlarged portion.
FIG. 5 is a longitudinal cross-sectional explanatory diagram showing an example of the structure of a rotary drive device provided with 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 (turn table)
134 Rotating shaft
20 Automatic balancing device
20a Upper hollow annular member
20b Lower hollow annular member
20c Hollow storage case body
20a1, 20b1 Inner peripheral side wall
20a2, 20b2 Outer peripheral side wall
20a3, 20b3 bottom wall
20d balance sphere
S Narrow gap (filler)
Sa filler injection passage
20a4 Flange
20a5 inclined taper wall (passage expansion part)
Sb Clearance expansion part

Claims (6)

The rotational speed of the motor unit that drives the rotating body is configured to cancel the rotational imbalance when the rotational speed of the rotating body exceeds the resonant rotational speed of the rotating body.
A plurality of balance spheres are accommodated in a freely movable manner on the inner side of a hollow housing case body composed of two hollow annular members fitted in the axial direction,
In the automatic balancing device of the motor that performs the balancing action by moving the balance sphere while contacting the outer peripheral wall of the hollow storage case body to a position where the rotational unbalance of the rotating body is canceled,
On the outer peripheral side of the hollow housing case body, two outer peripheral side standing wall portions respectively provided on the two hollow annular members are superposed so as to be close to the inside and outside with a narrow gap in the radial direction. And
In the narrow gap between the two outer peripheral side standing wall portions, there is interposed a filler that connects the two outer peripheral side standing wall portions so as to be integrated to increase the support rigidity against the contact pressure of the balance sphere. A motor automatic balancing device characterized by the above. Each of the two hollow annular members constituting the hollow storage case body is formed to have a substantially cup shape,
The two hollow annular members are disposed so that the substantially cup-shaped openings are opposed to each other in the axial direction,
2. The motor automatic balancing device according to claim 1, wherein the outer peripheral side standing wall portions of the two hollow annular members are respectively provided on the outer peripheral side of the substantially cup shape. In a portion where the narrow gap between the standing wall portions of the two hollow annular members opens to the outside, a filler injection passage communicating with the inner side of the narrow gap is provided,
2. The automatic balancing device for a motor according to claim 1, wherein the filler is injected from the filler injection passage toward the inside of the narrow gap using a capillary phenomenon. An outer opening portion of the filler injection passage is provided so that a passage cross-sectional area increases toward the outside of the motor, and the filler is stored in an appropriate amount in the passage enlarged portion. 4. The motor automatic balancing device according to claim 3, wherein the motor automatic balancing device is provided. Sealing the filler that flows from the narrow gap into the hollow housing case at a portion where the narrow gap between the standing wall portions of the two hollow annular members communicates with the inside of the hollow housing case. 4. The motor automatic balancing device according to claim 3, further comprising a gap enlarging portion that is provided. 5. The motor automatic balancing device 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.

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