JP2872035B2 - Spindle motor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a spindle motor used for a floppy disk or the like.

[0002]

2. Description of the Related Art An example of the structure of a conventional spindle motor is described in U.S. Pat. No. 5,132,856. Referring to FIG. 25 of the present application based on FIG. 1 of the publication, a rotor 91 is attached to a shaft 96. A magnet 92 is attached to the rotor 91. The magnet 92 faces the tip of the stator core 93. Stator core 93 is mounted on support substrate 94.
A coil 95 is wound around the stator core 93. When a current is supplied to the coil 95, a magnetic flux is generated at the tip of the stator core 93. This magnetic flux causes the magnet 92
The magnetic force works. This magnetic force rotates the rotor 91.

In recent years, computers have been rapidly reduced in size. For this reason, it is desired that the floppy disk drive mounted on the computer be further downsized. Among the shapes of the floppy disk drive, the width and the depth have been miniaturized. For this reason, a technique for making a floppy disk drive thinner is desired. In order to reduce the thickness T of the spindle motor shown in FIG. 25, the thickness of the stator core 93 or the coil 95 must be reduced.

[0004]

However, when the thickness of the stator core 93 is reduced, the magnetic flux passing through the poles of the stator core 93 decreases. This is because the stator core 93 is magnetically saturated. Here, the pole of the stator core 93 is a portion of the stator core 93 that extends radially. As the magnetic flux passing through the poles of the stator core 93 decreases, the torque of the spindle motor decreases.

When the diameter of the conductor constituting the coil 95 is reduced in order to reduce the thickness of the coil 95, the electric resistance of the coil 95 increases. When the electric resistance of the coil 95 increases, the current flowing through the coil 95 decreases. When the current flowing through the coil 95 decreases, the magnetic flux generated by the coil 95 decreases. When the magnetic flux generated by the coil 95 decreases, the magnetic flux passing through the stator core 93 decreases. As the magnetic flux passing through the stator core 93 decreases, the magnet 9
The magnetic force acting on 2 decreases. When the magnetic force acting on the magnet 92 decreases, the torque of the spindle motor decreases.

When the number of turns of the coil 95 is reduced in order to reduce the thickness of the coil 95, the magnetic flux generated by the coil 95 decreases. When the magnetic flux generated by the coil 95 decreases, the magnetic flux passing through the stator core 93 decreases. When the magnetic flux passing through the stator core 93 decreases, the magnetic force acting on the magnet 92 decreases. When the magnetic force acting on the magnet 92 decreases, the torque of the spindle motor decreases.

As described above, the technique of thinning the spindle motor by reducing the thickness of the stator core 93 or the coil 95 involves a reduction in the torque of the spindle motor.

[0008]

SUMMARY OF THE INVENTION An object of the present invention is to provide a spindle motor having a small thickness and a large torque.

Therefore, according to the aspect of the present invention described in the first embodiment, an opening is provided in the support substrate, and a part of the coil is inserted into the opening.

Another object of the present invention is to improve the rotation efficiency and stability of the spindle motor of the first embodiment. For this reason, according to the aspects of the present invention described in the second to fifth embodiments, a protruding portion is provided at the tip end portion of the stator core. The projecting portion projects in a direction away from the support substrate.

According to the aspect of the present invention described in the sixth embodiment, a part of the arm portion of the stator core is bent in a direction away from the support substrate.

[0012]

Next, a first embodiment of the present invention will be described with reference to the drawings.

Referring to FIG. 1, a spindle motor 10
0 is mounted on the floppy disk drive.
The spindle motor 100 includes a disk-shaped rotor 5 and a flat support substrate 4. The linear motor 8 is mounted on the support substrate 4 in addition to the spindle motor 100. The head 7 is attached to the linear motor 8. The printed circuit board 21 is also mounted on the support substrate 4. A control IC 22 is mounted on the printed board 21.

Referring to FIG. 2, the spindle motor 10
0 is the rotor 5, magnet 6, bearing 9 and drive coil 1
Contains 0. A cylindrical portion is formed around the rotor 5. The magnet 6 is formed in a circular shape. Magnet 6
Is fitted into the cylindrical portion of the rotor 5. Rotor 5
Is rotatably mounted on the support substrate 4 via a bearing 9.

Referring to FIG. 3, the drive coil 10 is molded with a resin. The molding is performed after a stator core 1 and a printed board 3 to be described later are attached to the support board 4. Drive coil 1 molded
0 is a cylindrical shape having a diameter of about 35 mm.

Referring to FIG. 4, a stator core 1 and a coil 2 are sealed inside a drive coil 10. Three holes 17 are formed in the bottom plate of the stator core 1. The thicknesses of the stator core 1 and the coil 2 are not different from the conventional ones.

Referring to FIG. 5, the stator core 1 has twelve arm portions 15 extending radially. Arm part 15
Is wound around the coil 2. At the tip of each arm part 15,
A tip portion 14 is provided. The tip portion 14 has a shape projecting in the circumferential direction. The stator core 1 is composed of laminated plate members. The plate member is an electromagnetic steel sheet such as a silicon steel sheet. The stator core 1 forms a part of a magnetic circuit.

FIG. 5 schematically shows the structure of the stator core 1, but does not show the exact dimensions thereof. The dimensions of each member are as follows. The diameter of the stator core 1 is about 35 mm. The length L1 of the arm portion 15 is about 5 m
m. The width L2 of the arm portion 15 is about 2 mm. The height L3 of the arm portion 15 is about 1.8 mm. Tip 1
4 has a width L4 of about 7 mm.

Referring to FIG. 6, printed circuit board 3 includes
Twelve openings 13a corresponding to each coil 2 are provided.

Referring to FIG. 7, the support substrate 4 is provided with twelve openings 13b corresponding to the respective coils 2. The support substrate 4 is also provided with three claws 18 inserted into the holes 17.

Referring to FIG. 8, the spindle motor 10
0 includes the rotor 5 and the stator core 1. Rotor 5
Includes a rotor yoke 51 forming an outer peripheral portion and a central portion 52. The rotor yoke 51 is made of a magnetic material. The rotor yoke 51 forms a part of a magnetic circuit. The central portion 52 is formed of a resin. The upper surface of the central portion 52 receives the hub. In the following, the central part 52
Is called the hub surface. The rotor 5 is mounted on a shaft 16. A spacer 19 is provided between the rotor 5 and the bearing 9. The spacer 19 is composed of two members. These two members are formed from members having little friction. Since the spacer 19 reduces the friction between the rotor 5 and the bearing 9, the rotor 5 rotates smoothly.

A circular magnet 6 is attached to the rotor 5.

On the printed circuit board 3, a wiring having a waveform called an FG pattern is formed. In response to the passage of the magnet 6, the FG pattern generates a rotation control signal. This rotation control signal is used for controlling the rotation of the rotor 5.

The printed board 3 is fixed on a support board 4. The opening 13a of the printed board 3 and the supporting board 4
And the opening 13b. The superimposed openings 13a and 13b provide 12 openings 13
Is formed.

The stator core 1 is fixed to a support substrate 4. The stator core 1 is fixed by fitting the claws 18 of the support substrate 4 into the holes 17 of the stator core 1. As described above, the coil 2 is wound around the stator core 1. The lower part of the coil 2 has a corresponding opening 13
Has been inserted.

The tip portion 14 of the stator core 1 is
Opposes. The gap between tip 14 and magnet 6 is about 0.2 mm.

The stator core 1 is formed by laminating five plate members.

By supplying a current to the coil 2,
Magnetic flux is generated at the tip of the stator core 1. The magnetic force acting between the magnetic flux and the magnet 6 causes the rotor 5 to rotate.

FIG. 9 schematically shows the structure near the opening 13 in the structure shown in FIG. 9 and 1
0, 13, 14, 15, 16, 17, 18, 19, 2
At 0, 21, 22, 23, and 24, the number of plate members forming the stator core 1 is reduced to two for simplification. Referring to FIG. 9, the lower part of coil 2 is inserted into opening 13. The insertion of the coil 2 into the opening 13 causes the stator core 1 to move lower than the conventional one. Due to the downward movement of the stator core 1, the thickness of the spindle motor 100 is smaller than that of the prior art.

In the structure shown in FIG. 9, the lines of magnetic force between the stator core 1 and the magnet 6 are as shown in FIG. Referring to FIG. 10B, a magnetic force 31 acts between the stator core 1 and the magnet 6. Since the stator core 1 has moved downward, the magnetic force 31 is inclined downward. Referring to FIG. 10C, the magnetic force 31 has not only a radial component 32 but also an axial component 33. As the stator core 1 moves downward, the axial component 33 becomes relatively large.

As described above, in the spindle motor 100 of the present embodiment, the opening 13 is provided in the support substrate 4, and the lower portion of the coil 2 is inserted into the opening 13. With such a structure, the spindle motor 100 of the present embodiment is thinner than the conventional one. Further, the thicknesses of the stator core 1 and the coil 2 of the spindle motor 100 of the present embodiment are not different from those of the conventional one. Therefore, the spindle motor 100 of the present embodiment has substantially the same torque as the conventional one.

Next, a second embodiment of the present invention will be described.

The purpose of this embodiment is to further enhance the performance of the spindle motor 100 of the first embodiment. To achieve this object, an additional member 11 is attached to the distal end portion 14 of the stator core 1 of the present embodiment. The structure other than the additional member 11 is the same as that of the first embodiment.

First, the background of this embodiment will be described.

As described above, in the spindle motor 100 of the first embodiment, the axial component 33 of the magnetic force 31 is relatively large due to the downward movement of the stator core 1. When the axial component 33 increases, the following phenomenon occurs.

First, there occurs a phenomenon that the rotation efficiency of the spindle motor 100 is reduced. Referring again to FIG. 8, the rotor 5 is pushed downward by the axial component 33 of the magnetic force 31. When the rotor 5 is pushed down, the two members constituting the spacer 19 are strongly pressed against each other. Therefore, the frictional force acting between the two members increases. As the frictional force generated by the spacer 19 increases, the rotation efficiency of the spindle motor 100 decreases.

Second, the shaft 16 and the hub surface 52 run out. The generation process of this phenomenon is as follows. The axial component 33 of the magnetic force 31 pushes down the magnet 6 attached to the rotor 5. However, the distance between the stator core 1 and the magnet 6 is slightly different in each part of the rotor 5. This difference is caused by a manufacturing error of the stator core 1 and the magnet 6. Stator core 1 and magnet 6
In a portion where the distance between them is short, the force for pushing down the magnet 6 is large. In a portion where the distance between the stator core 1 and the magnet 6 is far, the force for pushing down the magnet 6 is small. As described above, the magnitude of the downward urging force differs depending on each part of the rotor 5. As a result, the rotor 5 shakes. Rotor 5
Swings, the shaft 16 and the hub surface 52 swing.

Third, a phenomenon occurs in which the rotation speed of the spindle motor 100 changes. Hereinafter, this phenomenon is referred to as “rotational unevenness”. The process of generating uneven rotation is as follows. As described above, the axial component 33 of the magnetic force 31 causes the shaft 16 and the rotor 5 to oscillate. When the rotor 5 swings, a portion where the shaft 16 and the bearing 9 come into contact moves every moment. As the portion where the shaft 16 contacts the bearing 9 moves, the frictional force between the shaft 16 and the bearing 9 changes every moment. A change in the frictional force between the shaft 16 and the bearing 9 causes uneven rotation of the spindle motor 100.

Further, the rotational unevenness also occurs from the following process. As described above, the axial component 33 of the magnetic force 31
Causes vibration of the rotor 5. The runout of the rotor 5 is FG
The pattern disturbs the generated rotation control signal. The disturbance of the rotation control signal causes an obstacle to the control for rotating the rotor 5 at a constant speed.

As described above, in the spindle motor 100 according to the first embodiment, there may occur a phenomenon that the rotation efficiency is reduced, the shaft 16 and the hub surface 52 run out, and the rotation unevenness is deteriorated. These undesired phenomena are caused by an increase in the axial component 33 of the magnetic force 31. The second to sixth embodiments aim at avoiding these phenomena by reducing the axial component 33 of the magnetic force 31. Referring to FIG. , An additional member 11 is attached. The structure of the stator core 1 excluding the additional member 11 is the same as that of the first embodiment.

Referring to FIG. 12, the width L5 of the additional member 11 is about 7 mm. The height L6 of the additional member 11 is about 0.4 mm. The dimensions of other parts are the same as those of the first embodiment.

Referring to FIGS. 13A and 13B, the stator core 1 includes a plate-like member 1a and a plate-like member 1b. The plate-like members 1a and 1b are electromagnetic steel plates such as silicon steel plates. Plate member 1a
And the plate-shaped member 1b is laminated. Plate member 1a
The tip of the plate-like member 1b is formed in a T-shape. The T-shaped portions are stacked to form the tip portion 14.

The additional member 11 is mounted on the tip portion 14 by bonding. The additional member 11 can also be attached by the same crimping technique used for laminating the plate members 1a and 1b. The additional member 11 is a plate-like member having the same shape as the distal end portion 14. The material of the distal end portion 14 is the same as that of the plate-like member 1a and the plate-like member 1b.

Referring to FIG. 14, the additional member 11 protrudes away from the substrate.

In the structure shown in FIG. 14, magnetic lines of force as shown in FIG. 15A are formed between the additional member 11 and the magnet 6. Referring to FIG. 15B, a magnetic force 31 acts on the magnet 6. Due to the presence of the additional member 11, the magnetic force 31 is corrected so as to be directed in the horizontal direction. Referring to FIG. 15C, the axial component 33 of the magnetic force 31 is smaller than that of the first embodiment shown in FIG. 10C.

As described above, in this embodiment, the additional member 11 protruding in the direction away from the support substrate 4 is provided at the tip end portion 14 of the stator core 1. The additional member 11 reduces the axial component 33 of the magnetic force 31. For this reason, in the spindle motor 100 of the present embodiment, the rotational efficiency, the runout of the shaft 16 and the hub surface 52, and the rotational unevenness are each improved as compared with those of the first embodiment.

Next, a third embodiment of the present invention will be described.

The feature of this embodiment lies in the structure of the tip portion 14 of the stator core 1. The structure of other parts is the same as that of the second embodiment.

Referring to FIG. 16A, the tip portion 14 of the stator core 1 of this embodiment has the same shape as the arm portion 15.

The additional member 11 has a rectangular parallelepiped shape. The dimensions of the additional member 11 are a vertical width L7 of about 2 mm, a horizontal width L8 of about 7 mm, and a height L9 of about 1 mm. The additional member 11 is formed of the same material as the stator core 1.
A notch 23 is provided in the additional member 11. The tip portion 14 fits into the notch 23.

Referring to FIGS. 17 (a) and 17 (b), the tip portion 14 of the stator core 1 protrudes away from the substrate due to the attachment of the additional member 11.

Since the tip portion 14 protrudes in the direction away from the substrate, the same effect as that of the second embodiment can be achieved by the structure of the third embodiment.

Next, a fourth embodiment of the present invention will be described.

The feature of this embodiment lies in the structure of the tip portion 14 of the stator core 1. The structure of other parts is the same as that of the second embodiment.

Referring to FIGS. 18A and 18B, the stator core 1 of this embodiment is formed by laminating the plate-like members 1a and 1b. The tip portions of the plate members 1a and 1b are formed in a T-shape. Plate member 1 which is the uppermost plate member
Further, flanges 12 are provided at both ends of the distal end portion a. The length L4 of the flange 12 is about 0.5 mm. The flange 12 is bent upward.

Referring to FIG. 19, flange 12 protrudes in a direction away from support substrate 4. For this reason,
With the structure of the fourth embodiment, the same effect as that of the second embodiment can be achieved.

Next, a fifth embodiment of the present invention will be described.

The feature of this embodiment resides in the structure of the flange 12 of the tip portion 14 of the stator core 1. The structure of the other parts is the same as that of the fourth embodiment.

Referring to FIGS. 20A and 20B, in this embodiment, the flange 12 is folded.

Referring to FIG. 21, the folded flange 12 protrudes away from the substrate.

The fifth embodiment achieves the same effect as the fourth embodiment.

Next, a sixth embodiment of the present invention will be described.

The feature of this embodiment lies in the structure of the arm portion 15 and the tip portion 14 of the stator core 1. The other structure is the same as that of the second embodiment.

Referring to FIG. 22, the additional member 11 is not attached to the distal end portion 14 of the stator core 1 of this embodiment. On the other hand, the arm portion 15 of the stator core 1 is bent upward at a portion indicated by reference numeral 24.

Referring to FIG. 23, the bent arm portion 15
As a result, the tip portion 14 moves in a direction away from the substrate. The distance moved is about 0.2 mm.

In the structure shown in FIG. 22, magnetic lines of force are formed between the additional member 11 and the magnet 6 as shown in FIG. Referring to FIG. 24B, a magnetic force 31 acts on the magnet 6. The magnetic force 31 is corrected so as to be directed in the horizontal direction by the upper end of the tip portion 14. Referring to FIG. 24 (c), the axial component 33 of the magnetic force 31 is smaller than that of the first embodiment shown in FIG. 10 (c).

As described above, in the sixth embodiment of the present invention, a part of the arm portion 15 of the stator core 1 is bent. The bent arm portion 15 causes the tip portion 14 to move away from the substrate. The axial component 33 of the magnetic force 31 acting between the stator core 1 and the magnet 6 is reduced due to the upper end of the tip portion 14. Therefore, in the spindle motor 100 of the present embodiment, the rotational efficiency, the runout of the shaft 16 and the hub surface, and the rotational unevenness are each improved as compared with those of the first embodiment.

The present invention can be implemented in various modifications in addition to the above embodiment.

For example, in the structure of the first embodiment, it is not necessary to provide openings in both the printed board 3 and the support board 4. For example, a structure in which an opening is provided only in the printed board 3 may be used. Further, the printed board 3 may have an opening, and the support board 4 may have a recess.

The shape of the additional member 11 in the second and third embodiments can be changed in any way as long as it protrudes in the direction away from the support substrate 4.
It should be changed according to the situation of the spindle motor to be applied.

The features of the second to sixth embodiments may be combined with each other. A feature of the second and third embodiments is that the additional member 11 is attached to the tip portion 14 of the stator core 1. A feature of the fourth and fifth embodiments is that a flange 12 is provided at the tip portion 14 of the stator core 1 and is bent. The feature of the sixth embodiment is that the arm portion 15 of the stator core 1 is bent and the tip portion 1 is bent.
4 in a direction away from the substrate. For example, by combining the features of the first and third embodiments with the features of the sixth embodiment, a structure in which the additional member 11 is attached to the distal end portion 14 and the arm portion 15 is bent can be obtained. .

Further, the features of the second to sixth embodiments may be applied to structures other than the first embodiment. That is, the second
The structure of the sixth to sixth embodiments may be applied to a spindle motor in which an opening is not provided in the support substrate 4.

[0073]

As described above, according to the first embodiment of the present invention, the effect that the spindle motor can be made thinner without reducing the torque is achieved.
Further, according to the second to sixth embodiments of the present invention, the effect that the rotation stability of the spindle motor according to the first embodiment can be improved is achieved.

[Brief description of the drawings]

FIG. 1 shows a first example mounted on a floppy disk drive.
FIG. 2 is a perspective view showing a spindle motor 100 according to the embodiment.

FIG. 2 is an exploded view showing the internal structure of the spindle motor 100 according to the first embodiment.

FIG. 3 is a perspective view showing the appearance of the drive coil 10 of the first embodiment.

FIG. 4 shows a stator core 1 and a coil 2 according to the first embodiment.
FIG.

FIG. 5 is a perspective view showing the structure of a stator core 1 according to the first embodiment.

FIG. 6 is a perspective view showing the structure of a printed circuit board 3 according to the first embodiment.

FIG. 7 is a perspective view showing the structure of a support substrate 4 according to the first embodiment.

FIG. 8 is a sectional view showing the structure of the spindle motor 100 according to the first embodiment.

FIG. 9 is a sectional view schematically showing a structure of a spindle motor 100 according to the first embodiment.

FIG. 10A is a diagram schematically showing the state of the lines of magnetic force 30 in the structure shown in FIG. 9; (B) is a diagram schematically showing a magnetic force 31 acting between the stator core 1 and the magnet 6 in the structure shown in FIG. 9. FIG.
The figure which shows the radial direction component 32 and the axial direction component 33 of the magnetic force 31 shown to (b).

FIG. 11 is a perspective view showing the structure of a stator core 1 and a coil 2 according to a second embodiment.

FIG. 12 is a perspective view showing the structure of a stator core 1 according to a second embodiment.

FIG. 13A is a perspective view schematically showing a structure of a distal end portion 14 of a stator core 1 according to a second embodiment. (B)
FIG. 9 is an exploded view schematically showing a structure of a tip portion 14 of the stator core 1 according to the second embodiment.

FIG. 14 is a sectional view schematically showing the structure of a spindle motor 100 according to a second embodiment.

FIG. 15A is a view schematically showing a state of magnetic lines of force 30 in the structure shown in FIG. 14; (B) is a diagram showing a magnetic force 31 acting between the stator core 1 and the magnet 6 in the structure shown in FIG. 15C is a diagram showing a radial component 32 and an axial component 33 of the magnetic force 31 shown in FIG.

FIG. 16A is a perspective view schematically showing a structure of a distal end portion 14 of a stator core 1 according to a third embodiment. (B)
FIG. 9 is an exploded view schematically showing a structure of a tip portion 14 of a stator core 1 according to a third embodiment.

FIG. 17A is a sectional view schematically showing a structure of a spindle motor 100 according to a third embodiment. FIG.
The figure which looked at the structure of (a) from the A direction.

FIG. 18A is a perspective view schematically showing a structure of a distal end portion 14 of a stator core 1 according to a fourth embodiment. (B)
FIG. 11 is an exploded view schematically showing a structure of a tip portion 14 of a stator core 1 according to a fourth embodiment.

FIG. 19 is a sectional view schematically showing the structure of a spindle motor 100 according to a fourth embodiment.

FIG. 20 (a) is a perspective view schematically showing a structure of a distal end portion 14 of a stator core 1 according to a fifth embodiment. (B)
FIG. 13 is an exploded view schematically showing a structure of a tip portion 14 of a stator core 1 according to a fifth embodiment.

FIG. 21 is a sectional view schematically showing the structure of a spindle motor 100 according to a fifth embodiment.

FIG. 22 is a front end portion 1 of a stator core 1 according to a sixth embodiment.
4 is a perspective view schematically showing the structure of FIG.

FIG. 23 is a sectional view schematically showing a structure of a spindle motor 100 according to a sixth embodiment.

FIG. 24A is a view schematically showing a state of magnetic lines of force 30 in the structure shown in FIG. 23; (B) is a diagram showing a magnetic force 31 acting between the stator core 1 and the magnet 6 in the structure shown in FIG. (C) is a diagram showing a radial component 32 and an axial component 33 of the magnetic force 31 shown in FIG. 24 (b).

FIG. 25 is a diagram showing a conventional technique.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Stator core 1a Plate-like member 1b Plate-like member 2 Coil 3 Printed circuit board 4 Support substrate 5 Rotor 6 Magnet 7 Head 8 Linear motor 9 Bearing 10 Drive coil 11 Additional member 12 Flange 13 Opening 14 Tip part 15 Arm part 16 Shaft 17 hole 18 Claw 19 Spacer 30 Magnetic field line 31 Magnetic force 32 Radial component 33 Axial component 51 Rotor yoke 52 Central part 100 Spindle motor

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-3-70461 (JP, A) JP-A-61-192672 (JP, U) JP-A-61-192680 (JP, U) JP-A-4-192680 72868 (JP, U) Japanese Utility Model 2-57275 (JP, U) (58) Fields studied (Int. Cl. ⁶ , DB name) H02K 29/00 H02K 1/14 H02K 21/00

Claims (3)

(57) [Claims] 1. A support substrate, and a disk-shaped row rotatably attached to the support substrate.
Motor and a magnet disposed on the circumference is attached to the rotor, before provided at a tip of the arm portion and said arm portion extending radially
And a tip portion facing the magnet, inside the magnet.
A magnetic stator arranged and fixed to the support substrate
A core , provided at the tip portion of the stator core,
A spindle including a protruding portion protruding in a direction away from the substrate and a coil wound around the arm portion
In the motor, the tip portion of the stator core is a first
A spindle motor including a plate-like member, wherein the top one of the first plate-like member has a flange , the flange being bent, and the flange constituting the projecting portion;
Ta. 2. The method according to claim 1, wherein the flange is separated from the support substrate.
Characterized by being bent so as to face
The spindle motor according to claim 1. 3. The method according to claim 2, wherein the flange is folded.
The spindle motor according to claim 1, wherein: