JP5300043B2 - STATOR, MOTOR, AND RECORDING MEDIUM DRIVE DEVICE - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a stator, a motor and a recording medium drive unit which can be reduced in thickness. <P>SOLUTION: The stator 6 is provide with a stator core which comprises: an annular part 21 arranged so as to oppose a permanent magnet, and formed with an axial line as a center; a plurality of teeth 22 fixed to the annular part at their base ends, and formed so as to oppose the permanent magnet; and tips 23 formed at tips of the teeth, respectively, and opposing the circumferential face of the permanent magnet. Coils 12 are selectively wound around the teeth of the stator core, and the stator core is placed on a base. The stator core is constituted of a first stator core 31 in which the coil-wound teeth 22a wound with the coils are formed out of all the teeth, and which is placed on the base, and a second stator core 32 formed with the teeth 22b not wound with the coils, and laminated on the first stator core. Coil accommodation parts are formed on the base in positions which correspond to the coils. <P>COPYRIGHT: (C)2009,JPO&amp;INPIT

Description

  The present invention relates to a stator, a motor, and a recording medium driving device.

  In recent years, an information recording / reproducing apparatus using a hard disk drive (HDD) has been adopted in portable music reproducing apparatuses, mobile phones, and the like. In particular, portable information recording / reproducing devices will become the mainstream in the future due to their convenience, and further miniaturization and thinning are required. Along with this, improvements in miniaturization and thinning of motors for driving HD (hard disks) have been made.

  In order to reduce the thickness of the motor, it is effective to increase the number of slots in the stator and reduce the cross-sectional area of the magnetic path per unit slot. However, when winding the conductor wire constituting the coil around the stator core teeth with the increased number of slots, the slot opening at the tip of the tooth becomes narrow, so that the winding machine can not enter, and the adjacent teeth approach, so the coil There is a problem that a winding space is narrowed and a necessary number of windings cannot be secured.

Here, according to the motor of Patent Document 1, the winding core is configured by a plurality of cores in which a plurality of salient poles that are not adjacent to each other among the core salient poles (teeth) are coupled at the inner peripheral portion. After winding, the combination is disclosed. Further, according to the stator device of Patent Document 2, two or more magnetic poles (teeth) are provided from the hub of the magnetic pole piece, and a metal wire (coil) is wound around each magnetic pole of the magnetic pole piece to form the magnetic pole piece set. A structure in which the center holes of two or more pairs of magnetic pole pieces are formed and inserted through a coupling member is disclosed.
Japanese Patent Laid-Open No. 9-46941 JP 2002-369421 A

By the way, in the motor of Patent Document 1, the shape of the divided core is complicated, and the core is formed by compacting. Therefore, since such a core is weak in strength, if the core is thinned (downsized), the core is easily broken, and it is difficult to reduce the thickness.
Further, in the stator device of Patent Document 2, when two or more sets of magnetic pole pieces are stacked, the position of the coil is shifted in the stacking direction.

  Accordingly, the present invention has been made in view of the above-described circumstances, and provides a stator, a motor, and a recording medium driving device that can be reduced in thickness.

In order to solve the above problems, the present invention provides the following means.
A stator according to the present invention is disposed so as to face a permanent magnet that rotates about an axis, and has an annular portion that is formed in an annular shape around the axis, and a base end that is fixed to the annular portion, and at a predetermined angle. A plurality of tooth pole portions formed so as to extend in the radial direction toward the permanent magnet, and tip portions respectively formed at the tips of the plurality of tooth pole portions and facing the peripheral surface of the permanent magnet, In the stator in which the coil is selectively wound around the tooth pole portion of the stator core and the stator core is placed on the base, the stator core is configured to have all of the tooth pole portions. A coil wound tooth pole portion around which the coil is wound is formed, a first stator core placed on the base is formed, and a tooth pole portion around which the coil is not wound is formed, and the first stator core is formed. Includes a second stator core that is laminated, and the base, the coil receiving portion is formed at a position corresponding to said coil, said coil winding tooth pole portion, formed on the second stator core the It is comprised so that it may be located between tooth-pole parts, and the thickness of the lamination direction of the said coil wound by the said coil winding tooth-pole part is comprised below the thickness of a said 2nd stator core. It is a feature.

With this configuration, only the coil winding tooth pole portion of all the tooth pole portions is formed in the first stator core, so that a distance between adjacent coil winding tooth pole portions is ensured. The Therefore, when a coil is formed by winding a conductive wire around the coil winding tooth pole portion, a winding machine can be used, and the production efficiency can be improved. Moreover, when winding a conducting wire around a coil winding tooth pole part, since the tooth pole part which a coil is not wound is not arrange | positioned, the number of turns required for a coil can be wound reliably.
In addition, since a sufficient space is secured when winding, for example, the nozzle of the winding machine can be prevented from coming into contact with the insulating coating formed on the stator core, and damage such as scratching and peeling of the insulating coating can be prevented. be able to. Therefore, it is possible to prevent generation of dust and dust during use, which is a problem in a recording medium driving device such as a hard disk, and improve reliability.
Furthermore, by laminating the first stator core and the second stator core, it is configured as a stator in which all the tooth pole portions are arranged. Therefore, the stator can be thinned, and the function as the stator can be reliably achieved.
And since the coil accommodating part is formed in the position corresponding to the coil in the base in which a stator core is mounted, the thickness of a coil can be absorbed with a coil accommodating part. Therefore, there is an effect that the stator can be thinned.

Furthermore , it is possible to more reliably form a space for the winding machine on both sides of the coil winding tooth pole portion, and to efficiently wind a conductive wire around the coil winding tooth pole portion to form a coil. .
In addition, the tip portion of the first stator core is bent toward the second stator core, and the tip portion of the second stator core is bent toward the first stator core. .
In addition, the coil housing portion is configured by a through-hole penetrating the base in the axial direction.

The stator according to the present invention is disposed so as to face a permanent magnet that rotates around an axis, and has an annular portion that is formed in an annular shape around the axis, and a base end that is fixed to the annular portion and has a predetermined shape. A plurality of tooth pole portions formed so as to extend in the radial direction toward the permanent magnet at each angle, and a tip portion formed at each of the tip ends of the plurality of tooth pole portions and facing the peripheral surface of the permanent magnet A stator core having a stator core, wherein a coil is selectively wound around a tooth pole portion of the stator core, and the stator core is mounted on a base. And at least two coil wound tooth pole portions formed in the coil wound tooth pole portion, and a third stator core divided on the annular portion and placed on the base, Coils tooth pole portion not wound is formed, a fourth stator core that is laminated on the third stator core, in a configuration, wherein the base, the coil receiving portion is formed at a position corresponding to said coil, The coil winding tooth pole portion is configured to be positioned between the tooth pole portions formed on the fourth stator core, and the stacking direction of the coils wound around the coil winding tooth pole portion Is configured to be equal to or less than the thickness of the fourth stator core .

By configuring in this manner, the third stator core is formed with only the coil winding tooth pole portion of all the tooth pole portions, so that a distance between adjacent coil winding tooth pole portions is ensured. Is done. Therefore, when a coil is formed by winding a conductive wire around the coil winding tooth pole portion, a winding machine can be used, and the production efficiency can be improved. Moreover, when winding a conducting wire around a coil winding tooth pole part, since the tooth pole part which a coil is not wound is not arrange | positioned, the number of turns required for a coil can be wound reliably.
In addition, when the coil wound tooth pole portion is disposed on two continuous tooth pole portions, the third stator core is divided between the two tooth pole portions, so that the coil wound tooth pole portion is A space is secured on the side, and the conductor can be efficiently wound around the coil winding tooth pole portion using a winding machine.
Further, by stacking the third stator core and the fourth stator core, it is configured as a stator in which all the tooth pole portions are arranged. Therefore, the stator can be thinned, and the function as the stator can be reliably achieved.
And since the coil accommodating part is formed in the position corresponding to the coil in the base in which a stator core is mounted, the thickness of a coil can be absorbed with a coil accommodating part. Therefore, there is an effect that the stator can be thinned.

Furthermore , it is possible to more reliably form a space for the winding machine on both sides of the coil winding tooth pole portion, and to efficiently wind a conductive wire around the coil winding tooth pole portion to form a coil. .
In addition, the tip portion of the third stator core is bent toward the fourth stator core, and the tip portion of the fourth stator core is bent toward the third stator core. .
In addition, the coil housing portion is configured by a through-hole penetrating the base in the axial direction.

In addition, a motor according to the present invention includes the stator according to any one of the present inventions described above, and a shaft body that is rotatably supported around the axis while holding the permanent magnet. It is what.
Since the motor according to the present invention includes the thinned stator, the motor itself can be thinned.

The recording medium driving apparatus according to the present invention includes the motor according to the present invention, a holding unit that is provided in the shaft body and holds a recording medium capable of recording various information, and rotates the shaft body around the axis. And a bearing portion that supports the bearing.
Since the recording medium driving device according to the present invention includes the motor which is thinned, the recording medium driving device itself can be thinned.

According to the stator according to the present invention, since only the coil wound tooth pole portion of all the tooth pole portions is formed in the first stator core, the distance between the adjacent coil tooth pole portions is ensured. The Therefore, when a coil is formed by winding a conductive wire around the coil winding tooth pole portion, a winding machine can be used, and the production efficiency can be improved. Moreover, when winding a conducting wire around a coil winding tooth pole part, since the tooth pole part which a coil is not wound is not arrange | positioned, there exists an effect which can wind the number of turns required for a coil reliably.
In addition, since a sufficient space is secured when winding, for example, the nozzle of the winding machine can be prevented from coming into contact with the insulating coating formed on the stator core, and damage such as scratching and peeling of the insulating coating can be prevented. be able to. Accordingly, it is possible to prevent generation of dust and dust during use, which is a problem in a recording medium driving device such as a hard disk, and to improve reliability.
Furthermore, by laminating the first stator core and the second stator core, it is configured as a stator in which all the tooth pole portions are arranged. Therefore, it is possible to reduce the thickness of the stator and to reliably perform the function as the stator.
And since the recessed part is formed in the position corresponding to the coil in the base in which a stator core is mounted, the thickness of a coil can be absorbed with a recessed part. Therefore, there is an effect that the stator can be thinned.

(First embodiment)
Next, a first embodiment of a stator, a motor, and a recording medium driving device according to the present invention will be described with reference to FIGS.
As shown in FIG. 1, a recording medium driving apparatus 1 includes a spindle motor (motor) 2 that rotates a hard disk (recording medium) D capable of recording various information around an axis L, and a hub of the spindle motor 2 to be described later. (Shaft body) 4, a fitting portion (holding portion) 4 c that fits and holds the hard disk D, and a fluid dynamic pressure bearing portion (bearing portion) 3 that supports the hub 4 rotatably about the axis L. It has.

  The spindle motor 2 includes a hub 4 supported so as to be rotatable around an axis L, an annular permanent magnet 5 held by the hub 4, and a stator 6 arranged so as to surround the permanent magnet 5. I have. That is, the spindle motor 2 of the present embodiment is an inner rotor type motor.

  The hub 4 has a shaft portion 4a formed in a substantially cylindrical shape with the axis L as a center, and is formed to extend radially outward from the outer peripheral surface of the shaft portion 4a. The flange portion of the fluid dynamic pressure bearing portion 3 to be described later And a flange portion 4b formed so as to sandwich 3b from above and below. Further, the upper end of the hub 4 is inserted into the center hole of the hard disk D and serves as the fitting portion 4c for fitting and holding the hard disk D. Further, the permanent magnet 5 is formed so that the cross section along the radial direction is rectangular, and the outer peripheral surface thereof is a surface in a direction parallel to the axis L. The permanent magnet 5 is held by the flange portion 4b.

  The fluid dynamic pressure bearing portion 3 includes a sleeve 3 a that is formed in a cup shape and has a base end fixed by a base 7, and an oil W that is supplied between the sleeve 3 a and the hub 4. . The sleeve 3a is an accommodating portion in which the inner side is formed in a circular shape and the shaft portion 4a is accommodated. Further, a flange 3b extending outward in the radial direction is formed at the upper end of the sleeve 3a. Further, a small gap is designed between the sleeve 3a and the hub 4 and oil W is supplied to the gap. The oil W is prevented from leaking to the permanent magnet 5 side by a seal (not shown).

Further, a plurality of thrust dynamic pressure generating grooves (not shown) called herringbone grooves are formed on the upper and lower outer surfaces of the flange portion 3b facing the flange portion 4b. Similarly, a plurality of radial dynamic pressure generating grooves called herringbone grooves (not shown) are formed on the inner peripheral surface of the sleeve 3a facing the outer surface of the shaft portion 4a. As a result, when the hub 4 rotates, the oil W flows along the thrust dynamic pressure generating grooves and the radial dynamic pressure generating grooves to increase the pressure, and the hub 4 rotates stably.
That is, the thrust dynamic pressure generating groove and the radial dynamic pressure generating groove are part of the fluid dynamic pressure bearing portion 3.

  The stator 6 is disposed so as to surround the periphery of the permanent magnet 5, and includes a stator core 11 and a coil 12. The stator core 11 is formed by laminating (for example, two layers) magnetic bodies (such as silicon steel plates) punched by a press or the like, and the surface is coated with an insulating film (not shown).

  FIG. 2 is a top view of the stator 6 (the stator core 11 and the coil 12). As shown in FIG. 2, the stator core 11 has a core back 21 formed in an annular shape and teeth (tooth portion) 22. The teeth 22 are fixed to the core back 21 and are formed so as to extend in the radial direction toward the permanent magnet 5, and a plurality of teeth 22 are provided at predetermined angles with the axis L as the center. In addition, the plurality of teeth 22 are tip portions 23 whose tips are opposed to the outer peripheral surface of the permanent magnet 5. In the present embodiment, 18 teeth 22 are formed every predetermined angle (20 °). Moreover, the coil 12 is provided only in the six coil winding teeth 22a distribute | arranged for every predetermined angle (60 degrees) among the teeth 22. FIG. That is, the coil winding teeth 22 a are positioned at every third of all the teeth 22.

  As shown in FIG. 3, the stator core 11 is configured by laminating two magnetic bodies. The 1st stator core 31 has the core back 21 formed in cyclic | annular form, and the coil winding teeth 22a. On the other hand, the 2nd stator core 32 has the core back 21 formed in cyclic | annular form, and the teeth 22b where a coil is not distribute | arranged. The tip 23 of the coil winding tooth 22a of the first stator core 31 is bent approximately 90 ° upward with respect to the coil winding tooth 22a toward the second stator core 32 side. On the other hand, the tip 23 of the tooth 22b of the second stator core 32 is bent approximately 90 ° downward with respect to the tooth 22b toward the first stator core 31 side. In this way, when the first stator core 31 and the second stator core 32 are stacked, the front end portion 23 is formed at substantially the same height in the circumferential direction by bending the front end portion 23, and the permanent magnet 5. Each front-end | tip part 23 will oppose on substantially the same conditions.

  Here, a conductive wire is wound around the first stator core 31 to form the coil 12. Since only the coil winding teeth 22a are formed on the first stator core 31 every 60 °, the conductive wire can be wound using a winding machine.

  4 is a cross-sectional view taken along line AA in FIG. As shown in FIG. 4, the coil 12 is wound around the coil winding tooth 22a. Further, when the first stator core 31 and the second stator core 32 are laminated, the thickness of the coil 12 on the second stator core 32 side is substantially the same as the upper surface 32 a of the second stator core 32. Here, the first stator core 31 is placed on the base 7. A through-hole 15 is formed at a position corresponding to the coil 12 in the base 7. The bulging portion 25 on the base 7 side of the coil 12 is arranged so as to be positioned in the through hole 15 of the base 7. Note that the thickness of the coil 12 on the second stator core 32 side may be configured to be lower (thinner) than the upper surface 32a of the second stator core 32.

(Manufacturing method of stator)
Next, the manufacturing method of the stator 6 of this embodiment is demonstrated.
First, the first stator core 31 and the second stator core 32 are prepared. At this time, the first stator core 31 and the second stator core 32 are not stacked.
A coil 12 is formed by winding a conductive wire around the coil winding tooth 22a of the first stator core 31 using a winding machine.
After the coils 12 are formed on all the coil wound teeth 22a, the first stator core 31 and the second stator core 32 are laminated, and the annular portions 21 are joined to each other by welding, adhesion, caulking, or the like.
The stator core is placed on the base 7 in a state where the first stator core 31 and the second stator core 32 are laminated. At this time, the coil 12 is placed so as to be positioned in the through hole 15 of the base 7. By doing so, the manufacture of the stator 6 is completed.

  According to the present embodiment, since only the coil winding teeth 22a among all the teeth 22 are formed on the first stator core 31, a distance between adjacent coil winding teeth 22a is secured. Therefore, when forming the coil 12 by winding a conducting wire around the coil winding tooth 22a, a winding machine can be used, and the production efficiency can be improved. Moreover, when winding a conducting wire around the coil winding teeth 22a, the teeth 22b around which the coil 12 is not wound are not disposed, so that the necessary number of turns can be wound around the coil 12.

  In addition, since a sufficient space is secured in the first stator core 31 during winding, for example, the nozzle of the winding machine can be prevented from coming into contact with the insulating coating formed on the first stator core 31, and the insulating coating can be prevented. Damage such as scratches and peeling can be prevented. Therefore, it is possible to prevent generation of dust and dust during use, which is a problem in the recording medium driving device 1, and to improve reliability.

  Further, the first stator core 31 and the second stator core 32 are laminated to constitute the stator 6 in which all the teeth 22 are arranged. Therefore, the thickness of the stator 6 can be reduced, and the function as the stator 6 can be reliably achieved.

  And the through-hole 15 was formed in the base 7, and the bulging part 25 by the side of the base 7 of the coil 12 was arrange | positioned in the through-hole 15. FIG. Therefore, even if the first stator core 31 is disposed so as to contact the base 7, interference between the coil 12 and the base 7 can be prevented. That is, the stator 6 can be further reduced in thickness by arranging the first stator core 31 in contact with the base 7.

  In addition, since two teeth 22b formed on the second stator core 32 are arranged between the coil wound teeth 22a formed on the first stator core 31, on both sides of the coil wound teeth 22a, The space for the winding machine can be formed more reliably, and the conductive wire can be efficiently wound around the coil winding teeth 22a.

  Furthermore, since the 1st stator core 31 and the 2nd stator core 32 are joined by the annular part 21 with a large area among stator cores, the magnetic loss by dividing the stator core 11 can be made small.

(Second embodiment)
Next, a second embodiment of a stator, a motor, and a recording medium driving device according to the present invention will be described with reference to FIGS. Note that this embodiment is different from the first embodiment only in the configuration of the first stator core and the second stator core, and the other configurations are substantially the same as those in the first embodiment. Detailed description will be omitted.
FIG. 5 is a top view of the stator 106 (the stator core 111 and the coil 12). As shown in FIG. 5, the stator core 111 has an annular core back 21 and teeth 22. In addition, the plurality of teeth 22 are tip portions 23 whose tips are opposed to the outer peripheral surface of the permanent magnet 5. In the present embodiment, 18 teeth 22 are formed every predetermined angle (20 °). Moreover, the coil 12 is provided in coil winding teeth 22a other than the six teeth 22b arranged for every predetermined angle (60 degrees) among the teeth 22. That is, twelve coil winding teeth 22 a are formed in all the teeth 22.

  As shown in FIG. 6, the stator core 11 is configured by laminating two layers of magnetic bodies. The third stator core 133 has a core back 21 and coil winding teeth 22a. The third stator core 133 is composed of a plurality of divided cores 133 a separated by the core back 21. Two coil winding teeth 22a are formed on the split core 133a. That is, in the present embodiment, the third stator core 133 is composed of six divided cores 133a. Further, the teeth 22b of the fourth stator core 134 are positioned between the coil wound teeth 22a formed on the single divided core 133a. By comprising in this way, the distance of the coil winding teeth 22a of the division | segmentation core 133a is securable. On the other hand, the 4th stator core 134 has the core back 21 formed cyclically | annularly, and the teeth 22b in which a coil is not distribute | arranged. The distal end portion 23 of the coil winding tooth 22a of the third stator core 133 is bent by approximately 90 ° with respect to the coil winding tooth 22a toward the fourth stator core 134 side. The tip 23 of the tooth 22b of the fourth stator core 134 is bent by approximately 90 ° with respect to the tooth 22b toward the third stator core 133 side. By bending the tip portion 23 in this way, when the third stator core 133 and the fourth stator core 134 are laminated, the tip portion 23 is formed at substantially the same height in the circumferential direction. Each front-end | tip part 23 will oppose on substantially the same conditions.

  And the stator core 111 is comprised by arrange | positioning so that the teeth 22b of the 4th stator core 134 may be pinched | interposed by the two coil winding teeth 22a of the split core 133a, respectively.

  FIG. 7 is a sectional view taken along line BB in FIG. As shown in FIG. 7, the coil 12 is wound around the coil winding tooth 22a. Further, when the third stator core 133 and the fourth stator core 134 are laminated, the thickness of the coil 12 on the fourth stator core 134 side is substantially the same height as the upper surface 134 a of the fourth stator core 134. Here, the third stator core 133 is placed on the base 7. A through-hole 15 is formed at a position corresponding to the coil 12 in the base 7. The bulging portion 25 on the base 7 side of the coil 12 is arranged so as to be positioned in the through hole 15 of the base 7.

  According to this embodiment, substantially the same effect as the first embodiment can be obtained. Further, since the third stator core 133 is separated between the two continuous teeth 22 configured as the coil winding teeth 22a to form the split core 133a, the coil winding teeth 22a are arranged on the two consecutive teeth 22. Even in such a case, the conductive wire can be efficiently wound around the coil winding teeth 22a by using a winding machine.

  Further, since the teeth 22b formed on the fourth stator core 134 are arranged between the coil winding teeth 22a formed on the third stator core 133, the winding machine is provided on both sides of the coil winding teeth 22a. Can be more reliably formed, and the conductive wire can be efficiently wound around the coil winding teeth 22a.

It should be noted that the technical scope of the present invention is not limited to the above-described embodiment, and includes those in which various modifications are made to the above-described embodiment without departing from the spirit of the present invention. That is, the specific shapes, configurations, and the like given in the embodiment are merely examples, and can be changed as appropriate.
For example, although the present embodiment has been described using the recording medium driving device, the stator core having the above-described configuration may be employed in a generator or the like.
Further, in the present embodiment, the case where the through hole is formed at a position corresponding to the coil in the base has been described, but a concave portion that can accommodate the bulging portion of the coil may be formed.

1 is a schematic cross-sectional view of a recording medium driving device according to a first embodiment of the present invention. It is a top view of the stator in 1st embodiment of this invention. It is a disassembled perspective view of the stator core in 1st embodiment of this invention. It is sectional drawing which follows the AA line of FIG. It is a top view of the stator in 2nd embodiment of this invention. It is a disassembled perspective view (bottom view) of the stator core in 2nd embodiment of this invention. It is sectional drawing which follows the BB line of FIG.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Recording medium drive device 2 ... Motor 3 ... Fluid dynamic pressure bearing part (bearing part) 4 ... Hub (shaft body) 4c ... Fitting part (holding part) 5 ... Permanent magnet 6 ... Stator 7 ... Base 11, 111 ... Stator core 12 ... Coil 15 ... Through hole (coil housing part) 21 ... Core back (annular part) 22 ... Teeth (tooth portion) 22a ... Coil wound tooth (coil wound tooth pole portion) 23 ... Tip 31 ... No. DESCRIPTION OF SYMBOLS 1 Stator core (1st stator core) 32 ... 2nd stator core (2nd stator core) 133 ... 3rd stator core (3rd stator core) 134 ... 4th stator core (4th stator core) D ... Hard disk (recording medium) L ... Axis

Claims (8)

It is arranged to face the permanent magnet that rotates around the axis,
An annular portion formed in an annular shape centering on the axis, and a plurality of tooth pole portions having a base end fixed to the annular portion and extending in a radial direction toward the permanent magnet at predetermined angles And a stator core having tip portions formed respectively at the tips of the plurality of tooth pole portions and facing the peripheral surface of the permanent magnet,
In the stator in which a coil is selectively wound around the tooth pole portion of the stator core and the stator core is placed on a base,
The stator core is
Of all the tooth pole portions, a coil wound tooth pole portion around which the coil is wound is formed, and a first stator core placed on the base;
A tooth pole portion around which the coil is not wound is formed, and a second stator core laminated on the first stator core, and
In the base, a coil housing portion is formed at a position corresponding to the coil ,
The coil wound tooth pole portion is configured to be positioned between the tooth pole portions formed on the second stator core,
The stator having a thickness in the stacking direction of the coil wound around the coil wound tooth pole portion being equal to or less than a thickness of the second stator core .   The tip portion of the first stator core is bent toward the second stator core,
  The stator according to claim 1, wherein the tip portion of the second stator core is bent toward the first stator core.   3. The stator according to claim 1, wherein the coil housing portion is configured by a through-hole penetrating the base in the axial direction. It is arranged to face the permanent magnet that rotates around the axis,
An annular portion formed in an annular shape centering on the axis, and a plurality of tooth pole portions having a base end fixed to the annular portion and extending in a radial direction toward the permanent magnet at predetermined angles And a stator core having tip portions formed respectively at the tips of the plurality of tooth pole portions and facing the peripheral surface of the permanent magnet,
In the stator in which a coil is selectively wound around the tooth pole portion of the stator core and the stator core is placed on a base,
The stator core is
Among the coil wound tooth pole portions around which the coil is wound, at least two coil wound tooth pole portions are formed, and the third portion is divided at the annular portion and placed on the base. A stator core;
A tooth pole portion around which the coil is not wound is formed, and the fourth stator core is laminated on the third stator core,
In the base, a coil housing portion is formed at a position corresponding to the coil ,
The coil wound tooth pole portion is configured to be positioned between the tooth pole portions formed on the fourth stator core,
The stator having a thickness in the stacking direction of the coil wound around the coil wound tooth pole portion being equal to or less than a thickness of the fourth stator core .   The tip of the third stator core is bent toward the fourth stator core,
  The stator according to claim 4, wherein the tip portion of the fourth stator core is bent toward the third stator core.   6. The stator according to claim 4, wherein the coil housing portion is configured by a through-hole penetrating the base in an axial direction. The stator according to any one of claims 1 to 6 ,
And a shaft body supported rotatably around the axis while holding the permanent magnet. A motor according to claim 7 ;
A holding unit for holding a recording medium provided on the shaft body and capable of recording various kinds of information;
A recording medium driving device comprising: a bearing portion that rotatably supports the shaft body around the axis.

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