JP2000197332A - Stator core and motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To realize a small size and high performance motor which is easy to assemble. SOLUTION: A stator core 3 has a plurality of poles 31. An aperture 34 is formed in the center part of the stator core 3. Three screw holes 35 are formed around the aperture 34. The respective poles 31 are composed of arm parts 32, on which coils are wound and pole end parts 33 which are provided on the tips (outer circumference ends) of the arm parts 32 and face the inner circumferential surfaces of the permanent magnets of a rotor. The pole end part 33 is formed by bending a plate-shaped member in a direction approximately perpendicular with respect to the arm part 32. The length of the pole end part 33 in the axial direction of a rotor shaft is larger than the thickness (length in the axial direction) of the arm part 32. The respective bottom surfaces of a pair of such stator cores 3 as described are jointed with each other for constituting a stator.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a stator core and a motor provided with the stator core.

[0002]

2. Description of the Related Art FIG. 8 is a perspective view showing a structure of a stator core used in a conventional outer rotor type motor. As shown in FIG.
It has a plurality of magnetic poles 110 arranged radially from the center, and is formed by punching steel plates into a desired shape and stacking, for example, about 6 to 12 sheets. Each magnetic pole 110 has an arm 120 around which a coil is wound,
And a pole tip 130 located at an outer peripheral end of the rotor 0. The pole tip 130 faces the permanent magnet of the rotor.

However, since such a conventional stator core 100 is manufactured by laminating and fixing a large number of steel plates, there is a problem that the number of manufacturing steps is large and the productivity is low.

Further, because of the structure in which a number of steel plates are laminated, the arm portion 120 of the magnetic pole 110 and the magnetic pole end portion 130 have the same thickness (the length in the rotor rotation axis direction). as a result,
When a coil (not shown) is wound around the arm 120, the length of the arm 120 in the direction of the rotor rotation axis becomes larger than that of the pole tip 130 by the amount of the wound coil, and the pole tip 130 Dead space is created between the rotor and the rotor, resulting in poor space efficiency. Therefore, the size of the motor increases.

If the thickness of the magnetic pole tip portion 130 is increased to some extent (the number of stacked steel plates is increased) in order to secure an area for facing the permanent magnet of the rotor, the thickness of the arm portion 120 is accordingly increased. However, in this case, the length required for one turn of the winding becomes longer. Therefore, if the total length of the windings constituting the coil is fixed, the number of turns cannot be increased, and the motor torque must be increased. That is, there is a problem that there is a limit in improving the performance of the motor.

[0006]

SUMMARY OF THE INVENTION An object of the present invention is to provide a stator core and a motor which are easy to manufacture and assemble, and which enable a small and high-performance motor.

[0007]

This and other objects are achieved by the present invention which is defined below as (1) to (12).

(1) A stator core used for a stator of a motor and having a plurality of radially arranged magnetic poles, wherein the magnetic poles are positioned at an arm around which a coil is wound, and at a tip of the arm. And a pole tip facing a permanent magnet of the rotor, wherein a length of the pole tip in a rotor rotation axis direction is larger than a thickness of the arm.

(2) The stator core according to the above (1), wherein the magnetic pole tip portion is constituted by a plate-like member arranged substantially perpendicular to the arm portion.

(3) The stator core according to (2), wherein the pole tip is formed integrally with the arm and bent substantially perpendicular to the arm.

(4) Each of the arms and each of the pole tips are
The above (1), which is obtained by molding one metal plate.
The stator core according to any one of (1) to (3).

(5) The stator core according to any one of the above (1) to (4), wherein the surface of the magnetic pole end facing the permanent magnet is a plane or an arc-shaped surface.

(6) In a motor having a stator and a rotor, the stator may be configured as described in (1) to (5) above.
A motor comprising the stator core according to any one of the above.

(7) In a motor having a stator and a rotor, the stator may be configured as described in (1) to (5) above.
A motor, comprising a pair of stator cores described in any one of the above, wherein both stator cores are fixed so that their bottom surfaces are joined to each other.

(8) In a motor having a stator and a rotor, the stator may be configured as described in (1) to (5) above.
A motor, comprising: a pair of stator cores according to any one of the above, wherein both stator cores are fixed such that the positions of their magnetic poles coincide in the direction of the rotor rotation axis.

(9) The motor according to any one of (6) to (8), wherein the rotor rotates on an outer peripheral side of the stator.

(10) The motor according to any one of the above (6) to (9), further comprising a grip portion on the stator side.

(11) The motor according to the above (10), wherein the grip portion is a curved plate-shaped member provided so as to cover a part of the rotor.

(12) The motor according to the above (10) or (11), wherein the grip portion has a function of preventing foreign matter from entering the inside of the motor.

[0020]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a stator core and a motor according to the present invention will be described in detail based on preferred embodiments shown in the accompanying drawings.

FIG. 1 is an exploded perspective view showing an embodiment of the motor of the present invention as viewed obliquely from above, and FIG. 2 is an exploded perspective view showing an embodiment of the motor of the present invention as viewed obliquely from below. FIG. 3 is a longitudinal sectional view of an embodiment of the motor of the present invention, and FIG.
1 is a perspective view showing a structure of a stator core of the present invention.
In the following description, the direction of the rotation axis of the rotor (FIGS.
(Vertical direction in the middle) is simply referred to as “axial direction”.

As shown in FIGS. 1 to 4, the motor 1 of the present embodiment is a DC brushless motor,
Board holding member 5, bearing 6, board 7, mounting plate 8
, Rotor 9, screw (screw) 10, and washer 11
And Hereinafter, these structures will be described in detail.

The stator 2 includes a pair of the stator core 3 of the present invention, an insulating member 4, and an exciting coil (winding) not shown.

A pair of stator cores 3 having the same shape are joined so that their bottom surfaces 36 are joined together, and the positions of the magnetic poles 31 (positions of the magnetic pole tips 33) in the two stator cores 3 are aligned in the axial direction. And fixed. The structure of the stator core 3 will be described later in detail.

An insulating member 4 formed of, for example, a resin material is mounted on both stator cores 3. In this case, the insulating member 4 penetrates between the adjacent magnetic poles 31 of the stator core 3 and is mounted so as to cover the arm 32. By applying a winding from above the insulating member 4, an insulating state between the coil and the stator core 3 is ensured.

The insulating member 4 is mounted in a state where the two stator cores 3 are connected, and has a claw 41.
Has a function of joining (temporarily fixing) the two stator cores 3 by engaging with the arm portions 32 of the stator core 3.

An upper portion (small diameter portion) of the bearing 6 in the figure is inserted into an opening 34 formed at the center of the stator core 3. The bearing 6 is a member that rotatably supports the shaft 93 of the rotor 9. The bearing 6 is formed of a sliding bearing made of, for example, a sintered body. The type and form of the bearing are not particularly limited. For example, an oil-impregnated bearing or a bearing using a bearing may be used.

The bearing 6 has a step 61 in the axial direction, and the outer diameter of the lower part of the bearing 61 in the figure is larger than that of the upper part. The portion around the opening 34 of the lower stator core 3 abuts on the stepped portion 61.

At the outer periphery of the lower part (large diameter part) of the bearing 6,
A plurality of grooves 62 extending along the axial direction are formed. Screws 10 are inserted into three of the grooves 62.

The lower portion (large diameter portion) of the bearing 6 is located inside the substrate holding member 5.

The substrate pressing member 5 is a member having a substantially cylindrical shape, and a ring-shaped flange 51 protruding inward is formed at an upper portion thereof. This flange 5
Three screw escape holes 52 are formed inside 1. The screw 10 passes through the screw escape hole 52.

Further, three projections 53 projecting downward are formed on the outer periphery of the lower part of the substrate holding member 5. By inserting the projections 53 into the holes 72 of the substrate 7, positioning and fixing to the substrate 7 are performed.

The substrate 7 has an opening 71 through which the lower part of the bearing 6 is inserted, and three holes 72 into which the projections 53 are inserted.

At the edge of the opening 71, three notches 73 and three screw escape holes 74 are formed. The screw 10 passes through the screw escape hole 74. The notch 73 has a projection (dub) formed on the upper surface (inner surface) of the mounting plate 8.
83 is inserted to position the substrate 7 with respect to the mounting plate 8;
Fixation is made.

On the substrate 7, three Hall elements 7
5 is mounted. These Hall elements 75 are installed at positions facing the lower surface of the permanent magnet 91 of the rotor 9,
The rotation state (position and the like) of the rotor 9 is detected by the passage of the lines of magnetic force.

A drive circuit (drive control circuit) 76 for supplying power to the coils of the stator 2 and driving the motor 1 is mounted on the substrate 7.

The mounting plate 8 located at the lowermost part of the motor 1 has a shaft hole 81 through which the shaft 93 passes, three screw holes 82, and three projections (dubs) 83.
Lower ends (tips) of the three screws 10 for fixing the stator 2 and the like are screwed into corresponding screw holes (female screws) 82, respectively.

A grip 84 for gripping the motor 1 is provided upright at an edge of the mounting plate 8. The grip portion 84 is formed of a plate-like member curved in an arc shape.
The lower end outer peripheral surface of the yoke 92 of the rotor 9 is covered. Therefore,
The grip portion 84 also has a function of preventing foreign substances such as dust and dirt from entering the inside of the motor 1. This eliminates the need to separately install a dustproof cover or the like, which contributes to a reduction in the number of parts of the motor 1.

The provision of such a grip portion 84 eliminates the need to grip the rotor 9. For this reason, a load is applied to the shaft sliding surface (inner peripheral surface) of the bearing 6 by gripping the rotor 9, thereby preventing the shaft from shifting (tilting of the shaft) or being damaged. Thereby, the shaft 93
The verticality and the fixing strength are improved.

The grip 84 is formed integrally with the mounting plate 8. That is, it is formed by bending the edge of the mounting plate 84 almost vertically. Therefore, when the mounting plate 8 is formed, the grip portion 84 can be formed at the same time, thereby preventing an increase in the number of manufacturing steps and the number of parts, thereby contributing to cost reduction.

The rotor 9 is a so-called outer rotor which is installed so as to rotate on the outer peripheral side of the stator 2, and has a cylindrical permanent magnet 91, a yoke 92, a shaft (rotating shaft) 93, and a bush 94. It is composed of

The permanent magnet 91 is fixed to the inner peripheral surface of the yoke 92, and rotates integrally with the yoke 92. The shaft 93 is concentrically fixed to the yoke 92 via a bush 94. That is, the shaft 9 is
The bush 94 is fitted and fixed (press-fitted) into an opening 921 formed at the center of the top of the yoke 92.

A washer (ring-shaped member) 11 is inserted between the upper end of the bearing 6 and the bush 94.

A pulley 95 is fitted and fixed (press-fitted) into a portion of the shaft 93 protruding from the top of the yoke 92 (see FIG. 3).

As the permanent magnet 91, a magnet having excellent magnetic properties is used. For example, a permanent magnet composed mainly of a rare earth element and a transition metal (eg, an Sm-Co based magnet), or a rare earth element and a transition metal Various rare-earth magnets such as those containing boron as a basic component (eg, Nd—Fe—B-based magnet) are preferably used. Further, the form (kind) of the permanent magnet 92 may be any of a bonded magnet, a sintered magnet, a cast magnet, and the like.

The permanent magnet 91 is multipolarly magnetized in the radial direction.

The stator core 3 has a plurality of magnetic poles 31 arranged radially. In the center of the stator core 3, an opening 34 into which the upper part of the bearing 6 is inserted is formed, and around the opening 34, three screw holes 35 through which the screws 10 are inserted are formed.

Each of the magnetic poles 31 is positioned at an end (outer peripheral end) of an arm 32 which is a portion around which a coil (not shown) is wound, and is provided on the inner peripheral surface of the permanent magnet 91 of the rotor 9. And a magnetic pole tip 33 facing the magnetic pole. In this case, each arm portion 31 and each magnetic pole end portion 32 preferably form one metal plate (for example, press forming, header forming,
(Bending process).

Each magnetic pole tip 33 is arranged at an equal distance from the rotation center (shaft 93) of the rotor 9, that is, on a concentric circle.

In such a stator core 3, the axial length of the magnetic pole tip 33 is set to be greater than the thickness (axial length) of the arm 32. The details will be described below.

The arm portion 32 is a rod-shaped member having a square cross section, and the magnetic pole end portion 33 is formed of a plate-like member arranged substantially perpendicular to the arm portion 32. In this case, the magnetic pole tip 33 is formed integrally with the arm 32 and the arm 3
It is formed by bending substantially perpendicularly to 2.

The conventional stator core 100 shown in FIG. 8 has a problem that the number of parts is large, the number of manufacturing steps is large, and the productivity is low because a large number of steel sheets are laminated and fixed to manufacture. However, the stator core 3 of the present invention
Such a problem is solved. In particular, since it is obtained by molding one metal plate, the number of parts is small, the production is easy, and it is suitable for mass production.

By setting the axial length of the magnetic pole tip portion 33 to be greater than the thickness of the arm portion 32, the following operations and effects are produced.

First, the axial length of the pole tip 33, that is, the area of the surface (outer peripheral face) 331 of the pole tip 33 facing the permanent magnet 91 can be increased, and the area between the pole 9 and the rotor 9 (especially , Between the top of the yoke 92) and the substrate 7, while contributing to the improvement of the torque of the motor 1. In addition, since the thickness of the arm 32 can be reduced, the space in which the coil is housed (the space corresponding to the difference between the axial length of the magnetic pole tip 33 and the thickness of the arm 32). And the number of turns (number of turns) of the winding can be increased.

Further, since the thickness of the arm portion 32 is small, the number of turns of the winding can be increased as compared with the conventional stator core 100 when the total length of the winding constituting the coil is constant. Conversely, when the same number of turns is used as in the case where the conventional stator core 100 is used, the total length of the windings can be made shorter, and a thinner winding should be used in consideration of the reduction in electric resistance. Can be. As a result, the number of windings can be increased without increasing the electrical resistance in a limited coil installation space, and the torque of the motor 1 can be improved.

In the illustrated stator core 3,
The surface 331 of the pole tip 33 facing the permanent magnet 91 is a flat surface, but this surface 331 is an arc-shaped surface, particularly an arc-shaped surface corresponding to the curvature of the inner peripheral surface of the permanent magnet 91. You may. In this case, the gap between the surface 331 and the inner peripheral surface of the permanent magnet 91 can be made smaller, which contributes to the improvement of the torque of the motor 1.

In order to make the surface 331 arc-shaped, for example, there is a method of subjecting the magnetic pole tip 33 to plastic deformation by subjecting the flat magnetic pole tip 33 to press working or the like.

In the case where the surface 331 is flat as in this embodiment, the step of plastically deforming the magnetic pole tip 33 is unnecessary, so that the stator core 3 can be manufactured more easily. There is an advantage that can be.

Examples of the metal material forming the stator core 3 include a silicon steel plate, a cold-rolled steel plate (SPC), and an electromagnetic soft iron plate (SUYP).

The magnetic permeability of the metal material forming the stator core 3 is not particularly limited, but the initial magnetic permeability is 1000.
Or more, more preferably 15,000 or more.

Further, the surface of the stator core 3 may be subjected to rust prevention treatment, painting, or the like.

The assembly of the motor 1 as described above is performed as follows.

The two stator cores 3 are joined together such that their bottom surfaces 36 are joined together and the positions of the magnetic poles 31 in the two stator cores 3 are aligned in the axial direction. Arm 3 of magnetic pole 31
2 is wound to form a coil. Thereby, the stator 2 is completed.

Further, the substrate 7 is placed on the mounting plate 8 and the projections 83 and the corresponding notches 73 are fitted. Next, the bearing 6 is inserted into the opening 71 of the substrate 7, and the substrate pressing member 5 is put thereon. At this time, each projection 53 of the substrate holding member 5 is inserted into the corresponding hole 72 to perform positioning.

Further, the assembled stator 2 is mounted so that the upper part of the bearing 6 is inserted into the openings 34 of both stator cores 3. In this state, the step 61 of the bearing 6
, The portion around the opening 34 of the lower stator core 3 abuts.

The three screw holes 35 of the upper stator core 3
Then, screws 10 are inserted. Each screw 10 has a screw hole 35, a groove 62 and a screw escape hole 5 of both stator cores 3.
2, 74, the lower end of which the male screw is formed is screwed into the screw hole 82.

By rotating and tightening each screw 10, the distance between the stator 2 and the mounting plate 8 is reduced, and the bearing 6, the substrate pressing member 5 and the substrate 7 are clamped and fixed therebetween.

Both ends of the coil winding are electrically connected to predetermined terminals on the drive circuit 76 by, for example, soldering.

On the other hand, in the rotor 9, a permanent magnet 91 is fixed to the inner peripheral surface of the yoke 92, a bush 94 is fitted and fixed in an opening 921 of the yoke 92, and a shaft 94 is fitted and fixed in the bush 94. It is assembled by fixing the pulley 95 to the upper end of the shaft 94. Also,
The washer 11 is inserted through the shaft 93.

The rotor 9 assembled as described above
Is mounted over the stator 2 while the shaft 93 is inserted into the bore of the bearing 6, and is mounted. Shaft 93
Penetrates the bearing 6, and the lower end thereof protrudes from a shaft hole 81 formed in the mounting plate 8.

As described above, the assembly of the motor 1 is completed.

When a coil (winding) provided on the stator 2 is energized by the drive circuit 76 of the motor 1, the coil is excited to generate a magnetic flux at the magnetic pole 31, and a torque for driving the rotor 9 to rotate is generated.

The use of the motor of the present invention is not particularly limited. For example, the motor can be used for a head feed of a printer, a paper feed of a printer, a facsimile, a scanner, a copier, a disk drive, and the like.

Next, another embodiment of the stator core of the present invention will be described. In this case, description of common points with the above-described stator core will be omitted, and main differences will be described.

FIG. 5 is a perspective view showing another embodiment of the stator core of the present invention. Stator core 3a shown in FIG.
Has a plurality of magnetic poles 31 arranged radially. Each magnetic pole 31 is positioned at an end (outer peripheral end) of the arm 32 which is a portion around which a coil (not shown) is wound, and faces the inner peripheral surface of the permanent magnet 91 of the rotor 9. And a magnetic pole tip 33.

The axial length of the pole tip 33 is
Is set to be larger than the thickness (length in the axial direction). The arm portion 32 is a rod-shaped member having a square cross section, and the magnetic pole tip portion 33 is a plate-shaped member. In this case, the magnetic pole tip 33 is
At the end of the arm 32, the arm 32 is arranged substantially perpendicular to the arm 32. The arm portion 32 and the magnetic pole end portion 33 may be integrally formed, or may be formed by joining different members by, for example, welding or brazing.

On the bottom surface 36 side of the stator core 3a, the annular portion on the outer periphery of the opening 34, the arm portion 32, and the magnetic pole end portion 33 form the same plane. This allows
When the pair of stator cores 3a are joined such that their bottom surfaces 36 are joined to each other, there is little or no gap between the corresponding magnetic pole tips 33 of both stator cores 3a. This further improves the space efficiency and contributes to downsizing.

In the stator core 3a shown in FIG.
Surface (outer peripheral surface) 3 of the pole tip 33 facing the permanent magnet 91
31 is an arc-shaped surface (in particular, an arc-shaped surface corresponding to the curvature of the inner peripheral surface of the permanent magnet 91), but may be a flat surface.

In addition to the case where the stator 2 is constituted by the pair of stator cores 3a, the stator may be constituted by one stator core 3a.

FIG. 6 is a perspective view showing still another embodiment of the stator core of the present invention, and FIG. 7 is a longitudinal sectional view of the stator core shown in FIG.

The stator core 3b shown in these figures has a plurality of magnetic poles 31 arranged radially. Each magnetic pole 31
Is an arm 32 which is a part for winding a coil (not shown).
And a magnetic pole tip 33 located at the tip (outer circumference end) of the arm 32 and facing the inner circumference of the permanent magnet 91 of the rotor 9.

The axial length of the magnetic pole tip 33 is
Is set to be larger than the thickness (length in the axial direction). The arm portion 32 is a rod-shaped member having a square cross section, and the magnetic pole tip portion 33 is a plate-shaped member. In this case, the magnetic pole tip 33 is
At the end of the arm 32, the arm 32 is arranged substantially perpendicular to the arm 32. The arm portion 32 and the magnetic pole end portion 33 may be integrally formed, or may be formed by joining different members by, for example, welding or brazing.

As shown in FIG. 7, the magnetic pole tip 33 protrudes from the arm 32 in the axially upward direction and the axially downward direction. Stator core 3 having such a configuration
“b” is a single stator core 3b and has the same function as the pair of stator cores 3 or the pair of stator cores 3a described above. Therefore, it contributes to a reduction in the number of parts, an improvement in space efficiency, and an improvement in motor performance.

In the stator core 3b shown in FIGS. 6 and 7, the surface (outer peripheral surface) 331 of the pole tip 33 facing the permanent magnet 91 is an arc-shaped surface (particularly, the permanent magnet 91).
(An arc-shaped surface corresponding to the curvature of the inner peripheral surface), but may be a flat surface.

Although the stator core and the motor according to the present invention have been described based on the illustrated embodiments, the present invention is not limited to these embodiments. Anything that can produce a function can be appropriately replaced.

For example, the shape and number of the magnetic poles in the stator core are not limited to those shown in the figure, but may be any.

In the illustrated embodiment, the DC brushless motor has been described. However, the present invention is not limited to this.
The present invention can be applied to various motors such as a C brush motor, an AC motor, and a stepping motor (hybrid type, VR type, PM type).

Further, in the illustrated embodiment, an outer rotor type motor is described, but the present invention can be applied to an inner rotor type motor (a structure in which a rotor rotates inside a stator).

[0089]

As described above, according to the present invention, the number of parts can be reduced and the number of steps can be reduced, so that the stator core can be easily manufactured and assembled, and the yield can be improved. I do.

Further, the dead space can be reduced and the size of the motor can be reduced.

Further, the torque of the motor can be improved, and a higher performance motor can be provided.

[Brief description of the drawings]

FIG. 1 is an exploded perspective view showing a state of an embodiment of a motor according to the present invention as viewed obliquely from above.

FIG. 2 is an exploded perspective view showing a state of the motor according to the embodiment of the present invention when viewed obliquely from below.

FIG. 3 is a longitudinal sectional view of an embodiment of the motor of the present invention.

FIG. 4 is a perspective view showing the structure of the stator core of the present invention.

FIG. 5 is a perspective view showing another embodiment of the stator core of the present invention.

FIG. 6 is a perspective view showing another embodiment of the stator core of the present invention.

FIG. 7 is a longitudinal sectional view of the stator core shown in FIG. 6;

FIG. 8 is a perspective view showing the structure of a conventional stator core.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Motor 2 Stator 3 Stator core 3a Stator core 3b Stator core 31 Magnetic pole 32 Arm 33 Magnetic pole end 331 Surface 34 Opening 35 Screw hole 36 Bottom surface 4 Insulating member 41 Claw 5 Board holding member 51 Flange 52 Screw escape hole 53 Projection bearing 61 Part 62 Groove 7 Substrate 71 Opening 72 Hole 73 Notch 74 Screw Escape Hole 75 Hall Element 76 Drive Circuit 8 Mounting Plate 81 Shaft Hole 82 Screw Hole 83 Projection 84 Gripping Part 9 Rotor 91 Permanent Magnet 92 Yoke 921 Opening 93 Shaft 94 Bush 95 Pulley 10 Screw 11 Washer 100 Stator core (conventional) 110 Magnetic pole 120 Arm 130 Magnetic pole end

 ──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Koji Shinoka 3-5-5 Yamato, Suwa-shi, Nagano F-term in Seiko Epson Corporation (reference) 5H019 AA07 AA09 AA10 BB01 BB05 BB15 BB20 BB22 CC03 CC04 CC09 DD01 EE01 EE13 FF00 FF01 FF03 GG01 5H621 BB07 GA02 GA04 HH01 JK01 JK07 JK14 JK15 JK19

Claims (12)

[Claims] 1. A stator core used for a stator of a motor and having a plurality of radially arranged magnetic poles, wherein the magnetic poles are arranged at an end of a coil and an end of the arm. A magnetic pole end portion facing the permanent magnet, wherein a length of the magnetic pole end portion in a rotor rotation axis direction is larger than a thickness of the arm portion. 2. The stator core according to claim 1, wherein the magnetic pole end is formed of a plate-like member arranged substantially perpendicular to the arm. 3. The stator core according to claim 2, wherein the magnetic pole end portion is formed integrally with the arm portion and is bent substantially perpendicularly to the arm portion. 4. Each of the arms and the pole tips is obtained by molding a single metal plate.
The stator core according to any one of the above. 5. The stator core according to claim 1, wherein a surface of the magnetic pole end portion facing the permanent magnet is a flat surface or an arc-shaped surface. 6. A motor having a stator and a rotor, wherein the stator includes the stator core according to claim 1. 7. A motor having a stator and a rotor, wherein the stator includes a pair of the stator cores according to any one of claims 1 to 5, wherein both stator cores are fixed so as to join their bottom surfaces to each other. Motor. 8. A motor having a stator and a rotor, wherein the stator includes a pair of stator cores according to any one of claims 1 to 5, wherein both stator cores have their magnetic poles positioned in the direction of the rotor rotation axis. A motor characterized by being fixed so as to match. 9. The motor according to claim 6, wherein the rotor rotates on an outer peripheral side of the stator. 10. The motor according to claim 6, further comprising a grip on the stator side. 11. The motor according to claim 10, wherein the grip portion is a curved plate-shaped member provided so as to cover a part of the rotor. 12. The motor according to claim 10, wherein the grip has a function of preventing foreign matter from entering the inside of the motor.