JP3796081B2 - motor - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a motor in which a predetermined rotating body is mounted on a rotating body mounting portion of a rotor set having a rotor magnet and is driven to rotate.
[0002]
[Prior art]
In a motor that rotationally drives various recording media such as a CD-ROM, for example, as shown in FIG. 5, a rotating shaft 3 that is rotatably supported with respect to a bearing portion 2 of the stator assembly 1. In addition, a substantially thin dish-shaped rotor case 5 constituting the rotor assembly 4 is fixed. An annular magnet 6 is fixed on the inner peripheral surface side of the annular standing wall portion erected on the outer peripheral edge portion of the rotor case 5, and on the disk-like member 5a corresponding to the thin dish-shaped bottom surface portion. Various recording medium disks 7 such as CD-ROMs are directly mounted on the rotor case 5 via a ring-shaped mounting member 5b made of an elastic member.
[0003]
When the recording medium disk 7 is mounted, the central hole of the recording medium disk 7 is fitted to the disk boss portion 8 attached to the tip portion of the rotating shaft 3.
[0004]
[Problems to be solved by the invention]
However, the conventional motor described above has a structure in which the recording medium disk 7 is simply placed on the disk-shaped member 5 a of the rotor case 5, and the recording medium disk 7 is directly on the rotor case 5. Have a good contact relationship. As a result, the vibration generated in the rotor case 5 by the rotational electromagnetic force of the motor propagates directly to the recording medium disk 7 side, and the recording / reproducing function is caused by the large vibration of the recording medium disk 7. May be disturbed.
[0005]
SUMMARY OF THE INVENTION An object of the present invention is to provide a motor capable of performing stable rotational driving with a simple configuration and satisfactorily suppressing vibration propagation from a rotor set to a rotating body.
[0006]
[Means for Solving the Problems]
In order to achieve the above object, in the first aspect of the present invention, the rotor set supported rotatably with respect to the stator set includes a rotor magnet in which N poles and S poles are alternately magnetized over a plurality of poles. In the motor for rotating the rotor mounted on the rotor mounting portion of the rotor set by the magnetic action of the rotor magnet and the stator, the N pole and S pole of the rotor magnet in the rotor mounting portion A rotating body receiving portion that receives and supports the rotating body is provided at a plurality of locations in the circumferential direction at a portion corresponding to the magnetic pole boundary, and the rotating body is supported by the rotating body receiving portion for rotational driving. I try to do it.
[0007]
According to a second aspect of the present invention, the portion corresponding to the magnetic pole boundary between the N pole and the S pole of the rotor magnet according to the first aspect is magnetized around the magnetic pole boundary between the N pole and the S pole. The electrical angle is within a range of ± 30 °.
[0008]
Furthermore, in the invention according to claim 3, the rotor magnet according to claim 1 is composed of an annular magnet attached along the outer peripheral portion of the substantially thin dish-shaped rotor case, and the rotating body placing portion is It is made of a disk-shaped member corresponding to the bottom surface of the substantially thin dish-shaped rotor case.
[0009]
Furthermore, in the invention according to claim 4, the rotating body according to claim 3 is composed of a recording medium disk that is mounted so as to rotate together with the rotor case, and the rotating body receiving portion rotates the rotor case. It is characterized by being provided at three or more locations on substantially the same circumference in the body placement portion.
[0010]
In the invention according to claim 5, the rotating body receiving portion according to claim 3 is a convex portion formed at a portion corresponding to a magnetic pole boundary portion between the N pole and the S pole of the rotor magnet in the rotor case, or It consists of a recess formed in a portion corresponding to the magnetic pole center of the N pole or S pole of the rotor magnet.
[0011]
In the present invention having such a configuration, the rotating body receiving portion that receives the rotating body corresponds to the magnetic pole boundary between the N pole and the S pole of the rotor magnet that has the smallest absolute value or fluctuation value of the electromagnetic force in the thrust direction. Therefore, the propagation of vibration from the rotor set to the rotating body is minimized.
[0012]
At this time, as in the present invention, if the rotating body receiving portion is provided at three or more locations on substantially the same circumference, the rotating body is stably supported.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings.
First, in the embodiment shown in FIG. 1, the present invention is applied to a flat spindle motor that rotationally drives a CD-ROM disk. A bearing holder 11b having a stepped cylindrical shape is fixed to the substantially central portion. A stator core 11c made of laminated steel plate is attached to the outer peripheral wall surface of the bearing holder 11b, and a stator coil 11d is wound around each salient pole portion of the stator core 11c.
[0014]
On the other hand, a substantially cylindrical radial bearing portion 11e constituting a dynamic pressure bearing is integrally provided on the inner peripheral wall surface of the bearing holder 11b, and the rotor assembly 12 is configured via the radial bearing portion 11e. A rotating shaft 12a is rotatably supported. A retaining ring 12b for retaining is attached to the lower end portion in the axial direction of the rotating shaft 12a, and the lower end side curved surface 12c of the rotating shaft 12a opens the lower end side opening of the bearing holder 11b. It arrange | positions so that it may contact | abut with respect to the thrust bearing part 11f with which it was mounted | worn so that it might cover.
[0015]
On the other hand, a rotor boss 12d is press-fitted into a tip portion of the rotary shaft 12a on the upper end side in the figure, and the rotor boss 12d is fixed so as to rotate integrally with the rotary shaft 12a. Further, a disc-shaped portion 12f1 corresponding to the bottom surface portion of the rotor case 12f formed in a substantially thin plate shape is formed on the outer peripheral side portion of the disc-shaped rotor hub 12e integrally extending radially outward from the rotor boss 12d. Are connected so as to rotate together by caulking or the like. A cylindrical portion 12f2 that is erected so as to be bent in the axial direction is provided on the outer peripheral side of the disc-shaped portion 12f1 of the rotor case 12f, and a ring-shaped drive is provided on the inner peripheral wall surface of the cylindrical portion 12f2. A magnet 12g is attached in an annular shape.
[0016]
The annular drive magnet 12g has N poles and S poles, which are different magnetic poles, alternately magnetized over a plurality of poles along the circumferential direction, and the inner peripheral surface of the annular drive magnet 12g is The respective stator poles of the stator core 11d are arranged so as to face each other so as to approach from the radially outer side. A rotational driving force is applied to the entire rotor assembly 12 by a mutual magnetic action between the annular driving magnet 12g and each salient pole portion of the stator core 11d.
[0017]
The rotor boss 12d is screwed with a disk hub 12h that fits into a center hole of a CD-ROM disk (not shown), and the lower surface portion of the CD-ROM disk mounted around the disk hub 12h. Is supported on the disk-shaped portion 12f1 of the rotor case 12f via the disk receiving portion 12i.
[0018]
That is, as shown in FIG. 2, the disk-shaped portion 12f1 corresponding to the bottom surface of the substantially thin dish-shaped rotor case 12f is configured as a disk mounting portion. On the surface of the disk-shaped portion 12f1, a plurality of disk receiving portions 12i made of convex portions formed of a metal material or a rubber material are attached along substantially the same circumference.
[0019]
As shown in FIG. 3, each of the disk receiving portions 12i has a position immediately above the annular drive magnet 12g, more specifically, the magnetic poles of the N and S poles of the annular drive magnet 12g. They are respectively arranged at portions corresponding to the boundary portions, and are configured such that the CD-ROM disc is supported by the respective disc receiving portions 12i so as to be rotated and driven substantially horizontally.
[0020]
The portion corresponding to the magnetic pole boundary portion of the annular drive magnet 12g where each of the disk receiving portions 12i is arranged is within a range of ± 30 ° in the magnetization electric angle when the magnetic pole boundary between the N pole and the S pole is the center. It is set to become. In such a range of ± 30 °, the electromagnetic force in the thrust direction and its fluctuation are generated as compared with the case of 0 °, but the value is small enough to cause no problem in actual use. .
[0021]
That is, when the total circumferential length of a pair of N pole and S pole is 360 ° in terms of magnetization electrical angle, the magnetization electrical angle is 0 ° (magnetic pole boundary), 90 ° (magnetic pole center). , And 45 ° (between the magnetic pole boundary and the magnetic pole center), the results of calculation of the thrust electromagnetic force are shown in FIG. 4 (in the case of no excitation) and FIG. Case) respectively. As is clear from these figures, the fluctuation value of the thrust electromagnetic force is greatest at the position where the magnetization electric angle is 45 ° in both cases of non-excitation and excitation. It can be seen that it is the smallest at the pole boundary where the angle is 0 °.
[0022]
Accordingly, in the circumferential direction of the rotor case 12f, the vibration in the axial direction is the smallest at the portion corresponding to the magnetic pole boundary of the annular drive magnet 12g, and the CD-ROM as in the above-described embodiment. By arranging the position of each disk receiving portion 12i that directly receives the disk at a position corresponding to the magnetic pole boundary portion of the annular drive magnet 12g where the axial vibration is minimized, the rotor case 12f of the rotor set 12 is provided. Vibration to the CD-ROM disc can be minimized, and a very stable rotation state can be obtained.
[0023]
At this time, if the CD-ROM disc receiving portions 12i are provided at three or more locations on substantially the same circumference as in the above embodiment, the support of the CD-ROM disc is extremely stable. To be done.
[0024]
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.
[0025]
For example, in the above-described embodiment, the present invention is applied to a drive motor for a CD-ROM disk. However, the present invention is not limited to a disk, and is applicable to motors for driving various other rotating bodies. The same applies to the present invention.
[0026]
In the above-described embodiment, the rotating body receiving portion (disk receiving portion 12i) is formed from a convex portion, but a concave portion is formed in a portion corresponding to the magnetic pole central portion of the N pole or S pole of the rotor magnet. Even if the configuration is such that the magnetic pole center portion with large axial vibration is not brought into contact with the rotating body and, as a result, is supported at the magnetic pole boundary portion, An effect can be obtained.
[0027]
【The invention's effect】
As described above, according to the present invention, the rotating body receiving portion that directly receives the rotating body has a magnetic pole boundary between the N pole and the S pole of the rotor magnet that has the smallest absolute value and fluctuation value of the electromagnetic force in the thrust direction. Since it is the one that minimizes the propagation of vibration from the rotor set to the rotating body by arranging it in the part corresponding to the part, with a simple configuration, the rotating state of the rotating body can be very stabilized, Operation characteristics such as recording / reproduction can be greatly improved.
[0028]
In addition to the above configuration, the present invention is such that the rotor receiver is provided at three or more locations on substantially the same circumference, so that the rotor can be supported more stably. The effects described above can be further enhanced.
[Brief description of the drawings]
FIG. 1 is a longitudinal cross-sectional explanatory diagram showing the overall structure of a motor according to an embodiment of the present invention.
FIG. 2 is an external perspective explanatory view showing a rotor case used in the motor shown in FIG. 1;
FIG. 3 is a partially enlarged cross-sectional explanatory view showing a positional relationship between a rotor case and a rotor magnet used in the motor shown in FIG. 1;
FIG. 4 is a diagram showing a calculation result of a thrust electromagnetic force in each part of a rotor magnet of a motor in a non-excited state.
FIG. 5 is a diagram showing a calculation result of a thrust electromagnetic force at each part of a rotor magnet of a motor in an excited state.
FIG. 6 is a longitudinal cross-sectional explanatory view showing the overall structure of a general motor.
[Explanation of symbols]
11 Stator assembly 11b Bearing holder 11c Stator core 11e Radial bearing portion 12 Rotor assembly 12a Rotating shaft 12f Rotor case 12f1 Bottom disk-shaped portion 12g Drive magnet 12h Disc hub 12i Disc receiving portion

Claims (5)

A rotor assembly rotatably supported with respect to the stator assembly includes a rotor magnet in which N poles and S poles are alternately magnetized over a plurality of poles, and the rotor is mounted on a rotor mounting portion of the rotor assembly. In a motor that is driven to rotate by the magnetic action of the rotor magnet and the stator,
A rotating body receiving portion for receiving and supporting the rotating body is provided at a plurality of locations in the circumferential direction at a portion corresponding to the magnetic pole boundary between the N pole and the S pole of the rotor magnet in the rotating body mounting portion. A motor characterized in that the rotating body is supported by the rotating body receiving portion and is driven to rotate. The portion corresponding to the magnetic pole boundary between the N pole and the S pole of the rotor magnet is within a range of ± 30 ° in terms of magnetization electrical angle with the magnetic pole boundary between the N pole and S pole as the center. The motor according to claim 1. The rotor magnet is composed of an annular magnet attached along the outer peripheral portion of a substantially thin dish-shaped rotor case,
The motor according to claim 1, wherein the rotating body mounting portion is formed of a disk-shaped member corresponding to a bottom surface portion of the substantially thin dish-shaped rotor case. The rotating body is composed of a recording medium disk mounted so as to rotate with the rotor case,
The motor according to claim 3, wherein the rotating body receiving portion is provided at three or more locations on substantially the same circumference in the rotating body mounting portion of the rotor case. The rotating body receiving portion corresponds to a convex portion formed at a portion corresponding to a magnetic pole boundary portion between the N pole and the S pole of the rotor magnet in the rotor case, or a magnetic pole center portion of the N pole or S pole of the rotor magnet. The motor according to claim 3, comprising a recess formed in a part.

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