JP2003032982A - Cooling fan motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fan motor which has simple structure, feeds high output, and is suitable for efficiently cooling small-sized electronic components. SOLUTION: The fan motor is provided with a magnet formed into a cylindrical shape. At least the circumferential surface of the magnet is split in the circumferential direction, and the split portions are magnetized alternately by different poles. The magnet is rotatable on the center of rotation. Coils are placed in the axial direction of the magnet. The fan motor is provided with an outer magnetic pole portion, which is excited by the coils and faces the circumferential surface of the magnet; an inner magnetic pole portion which is excited by the coils, faces the inner circumferential surface of the magnet, and formed in hollow columnar shape; and a fan placed in the inner radius portion of the magnet, integrally with the magnet.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cooling fan motor having an extremely small size.

[0002]

2. Description of the Related Art Conventionally, electronic components and devices are cooled,
Alternatively, an axial fan motor is used to generate an air flow or an air circulation in order to accelerate heat dissipation, and its structure is disclosed in, for example, Japanese Patent Laid-Open No. 06-141507. Further, due to the demand for downsizing of equipment, further downsizing of the fan motor is desired.

A conventional example will be described below with reference to FIG. FIG. 16 is a sectional view showing a DC brushless fan motor to which the axial fan motor is applied. 101
Is a frame, and 102 is a drive circuit board on which electronic components are mounted. The drive circuit board 102 is the stator yoke plate 1
03 and the insulating sheet 104 are attached to the frame 101. Reference numeral 105 denotes a stator coil, which is wound in an air-core shape, and a plurality of them are symmetrically arranged on the insulating sheet 104 and fixed by adhesion. A lead portion (not shown) of the stator coil 105 is connected to a terminal portion (not shown) of the drive circuit board 102.

A plurality of blades 107 are integrally formed on the outer peripheral portion of the cylindrical blade holding portion 106. A rotor magnet 109 is fixed to the inner peripheral side of the blade holder 106 via a rotor yoke 108. Further, a rotary shaft 110 is fixedly provided at the center of the blade holding unit 106,
It is rotatably supported by the frame 101 via bearings 111 and 112.

When power is supplied from an external power supply circuit (not shown) and the stator coil 105 is energized via the drive circuit board 102, magnetic interaction occurs between the stator coil 105 and the rotor magnet 109. The blade holder 106 starts rotating. Therefore, the plurality of blades 107 integrated with the blade holder 106 rotate to form an air flow in the axial direction.

[0006]

However, in the case of the above-mentioned conventional example, the magnetic flux generated from the coil is large in size because the center of the rotational force generated by the magnet in FIG. 16 is located at a position L away from the outer diameter of the motor. For that reason, the generated torque becomes small. Further, since the coil and the magnet occupy the central portion of the motor, the air flow is generated only in the outer portion of the motor portion, and the small electronic component cannot be cooled efficiently.

Therefore, an object of the present invention is to provide a fan motor which is easy to manufacture, has a high output, and is suitable for efficiently cooling a small electronic component.

[0008]

In order to solve the above-mentioned problems, a cooling fan motor according to a first invention of the present application is formed in a cylindrical shape and at least the outer peripheral surface is divided in the circumferential direction to have different poles. A magnet that is alternately magnetized and rotatable about a rotation center, a coil is arranged in the axial direction of the magnet, and an outer magnetic pole portion that is excited by the coil and faces the outer peripheral surface of the magnet; A hollow pillar-shaped inner magnetic pole portion that is excited and faces the inner peripheral surface of the magnet, and a fan that is integrally arranged with the magnet in the inner diameter portion of the magnet are provided.

In the above structure, the diameter of the motor is determined by the outer magnetic poles that face the outer peripheral surface of the magnet, and the axial length of the motor is determined by arranging the coil and the magnet in that order, which greatly reduces the size of the motor. You can do things. Further, since the magnetic flux generated by the coil traverses the magnet between the outer magnetic pole and the inner magnetic pole, the magnetic flux acts effectively, so that an efficient motor can be obtained. Since the fan that rotates integrally with the magnet is arranged in the inner diameter portion of the hollow pole-shaped inner magnetic pole portion, the size of the motor itself does not increase. Further, since the fan can be configured near the center of the motor, even if a small electronic component is arranged near the center of rotation of the motor, it can be cooled efficiently.

Further, since the portion of the magnet that is the source of the torque is the outer diameter of the magnet, the present motor in which the magnet is formed on the outer diameter side of the fan is a motor that produces a large torque.

In order to solve the above-mentioned problems, a cooling fan motor according to a second invention of the present application is formed in a cylindrical shape, and at least the outer peripheral surface thereof is divided into N in the circumferential direction so that different poles are magnetized alternately. A magnet that is rotatable about a rotation center, and a coil is arranged in the axial direction of the magnet, and each coil is excited by the coil and separated from the outer peripheral surface of the magnet by an angle that is an integral multiple of (720 / N) degrees. A comb-teeth-shaped outer magnetic pole portion provided facing each other by a predetermined angle A, a hollow pillar-shaped inner magnetic pole portion which is excited by the coil and faces the inner peripheral surface of the magnet, and an inner diameter portion of the magnet. A fan integrally disposed with the magnet, wherein each of the comb-shaped opposite angles A of the outer magnetic pole portion facing the outer peripheral portion of the magnet, the outer diameter dimension D1 of the magnet, When the inner diameter D2 of the net A>
(248.4 / N) -58.86 x (D1-D2) / (D1 x
π) is set.

In the above structure, the diameter of the motor is determined by the outer magnetic poles facing the outer peripheral surface of the magnet, and the axial length of the motor is determined by arranging the coil and the magnet in this order, which makes the motor very compact. You can do things. Further, since the magnetic flux generated by the coil traverses the magnet between the outer magnetic pole and the inner magnetic pole, the magnetic flux acts effectively, so that an efficient motor can be obtained. Since the fan that rotates integrally with the magnet is arranged in the inner diameter portion of the hollow pole-shaped inner magnetic pole portion, the size of the motor itself does not increase. Further, since the fan can be configured near the center of the motor, even if a small electronic component is arranged near the center of rotation of the motor, it can be cooled efficiently.

Furthermore, since the portion of the magnet that is the source of torque generation is the outer diameter of the magnet, it can be a motor that generates a large torque.

Further, since the outer magnetic pole portion is formed in a comb-teeth shape which is provided on the outer peripheral portion of the magnet so as to face each other at a predetermined angle A, it is related to the radial direction as compared with the case where the outer magnetic pole portion is formed in the radial direction. The dimensions can be made thin. As a result, the outer diameter of the magnet can be increased, and the torque of the motor can be increased. Comb-tooth-shaped facing angles A of the outer magnetic pole portion facing the outer peripheral portion of the magnet
Degree, magnet outer diameter dimension D1, magnet inner diameter dimension D
If it is 2, A> (248.4 / N) −58.86 × (D1−
By setting D2) / (D1 x π), when the coil is not energized, the boundary between the magnetized poles of the magnet is positioned at the center of the comb teeth of the outer magnetic pole, and the motor stops. At the time of the first energization of the coil from time to time, the force exerted on the magnet by the magnetic flux generated from the coil does not go to the center of rotation of the magnet, and rotation can be stably started. Further, since the magnet and the outer magnetic pole are used as means for setting the initial position of the magnet to the position so that the rotation can be stably activated, the cost can be reduced.

In order to solve the above problems, a cooling fan motor according to a third invention of the present application has a hollow cylindrical magnet portion in which at least an outer peripheral surface is circumferentially divided and magnetized to different poles alternately. A rotor that is rotatable about a rotation center, a first coil, and a first hollow cylindrical magnet portion of the rotor that is excited by the first coil.
A first outer magnetic pole portion facing the outer peripheral surface within a predetermined angular range and a first inner magnetic pole portion that is excited by the first coil and faces the inner peripheral surface of the hollow cylindrical magnet portion of the rotor. , A second coil and an outer peripheral surface of the hollow cylindrical magnet part of the rotor, which is excited by the second coil and is outside the first predetermined angle range, facing the second predetermined angle range. A second inner magnetic pole portion that is excited by the second outer magnetic pole portion and the second coil and faces the inner peripheral surface of the hollow cylindrical magnet portion of the rotor, and the magnet is integrally formed on the inner diameter side of the magnet portion. It is characterized by the fact that it has a fan that is arranged in a targeted manner.

According to the above structure, the magnetic flux generated by the energization of the first coil is located between the first outer magnetic pole and the first inner magnetic pole, and the outer peripheral surface is divided in the circumferential direction into different poles. The magnetic flux effectively acting on the magnets alternately magnetized and generated by energizing the second coil is located between the second outer magnetic pole and the second inner magnetic pole, and the outer peripheral surface is divided in the circumferential direction. As a result, the magnets that are magnetized alternately on different poles are effectively acted on, so that the rotational output of the magnet is increased.

Further, the first outer magnetic pole and the second outer magnetic pole are
The magnets are configured to face each other in different angular ranges, and the regions facing the rotor in the direction parallel to the axial direction of the rotor overlap, so the magnets can be configured to be short in the axial direction, and A motor having a short length in the parallel direction can also be used. Further, since the first outer magnetic pole, the first inner magnetic pole, the second outer magnetic pole, and the second inner magnetic pole are excited by energizing the two coils, stable rotation can be obtained.

Since the fan that rotates integrally with the magnet is arranged in the inner diameter portion of the hollow pole-shaped inner magnetic pole portion, the size of the motor itself does not increase. Further, since the fan can be configured near the center of the motor, even if a small electronic component is arranged near the center of rotation of the motor, it can be cooled efficiently.

Further, since the portion of the magnet that generates torque is the outer diameter of the magnet, the present motor in which the magnet is formed on the outer diameter side of the fan becomes a motor that generates a large torque.

[0020]

DESCRIPTION OF THE PREFERRED EMBODIMENTS (Embodiment 1) FIGS. 1 to 6 are views showing a fan motor according to Embodiment 1 of the present invention.
1 is an exploded perspective view of the fan motor, FIG. 2 is an axial cross-sectional view of the fan motor after assembly, and FIGS. 3 to 6 are cross-sectional views taken along the line AA of FIG. FIG. 7 is a graph showing the state of coking torque. FIG. 8 is a graph showing the relationship between the width dimension of the outer magnetic pole, the coking torque, and the magnet dimension obtained by simulation.

1 to 6, reference numeral 1 denotes a cylindrical magnet which constitutes a rotor. The magnet 1 which is the rotor has its outer peripheral surface divided into n in the circumferential direction (in this embodiment, four divisions). Then> S pole and N pole are magnetized alternately. Assuming that the magnetized portions are 1a, 1b, 1c, 1d, the magnetized portions 1a, 1c are magnetized to the S poles, and the magnetized portions 1b, 1
d is magnetized to the N pole. The magnet 1 is made of a plastic magnet material formed by injection molding. Thereby, the thickness of the cylindrical shape in the axial direction can be made very thin.

A fan 7 is formed inside the cylindrical portion of the magnet. The fan 7 may be integrally formed with the magnet 1 or may be integrally formed by bonding. Further, the magnet 1 is provided with a fitting portion 1e at the center. A pin 20b of a cover 20, which will be described later, is slidably fitted and rotatable.

Reference numeral 2 denotes a cylindrical coil. The coil 2 is concentric with the magnet 1 and is arranged side by side in the axial direction of the magnet 1. The coil 2 has an outer diameter that is equal to that of the magnet 1.
The outer diameter is almost the same as the outer diameter.

A stator 18 made of a soft magnetic material is composed of an outer cylinder and an inner cylinder having a hollow cylindrical shape. The coil 2 is provided between the outer cylinder and the inner cylinder of the stator 18, and the stator 18 is excited by energizing the coil 2. The outer cylinder and the inner cylinder of the stator 18 have outer magnetic poles 18a, 18b and inner magnetic poles 18c, 18d formed at their tips, and the inner magnetic pole 18c and the inner magnetic pole 18d are in phase with each other 360. / <N / 2>
The outer magnetic pole 18a is arranged to face the inner magnetic pole 18c, and the outer magnetic pole 18b is arranged to face the inner magnetic pole 18d. The outer magnetic poles 18a and 18b of the stator 18 are composed of notch holes and comb teeth extending in a direction parallel to the axis. With this configuration, it is possible to form the magnetic pole while minimizing the diameter of the motor. In other words, if the outer magnetic pole is formed by the unevenness extending in the radial direction, the diameter of the motor is increased accordingly. However, in the present embodiment, the outer magnetic pole is formed by the notch hole and the comb tooth shape extending in the direction parallel to the shaft. The diameter of the motor can be minimized because it is configured.

In the present embodiment, the inner magnetic pole is formed in a comb shape like the outer magnetic pole by partially cutting out a hollow cylindrical shape, but only the inner magnetic pole may remain in the hollow cylindrical shape. If the outer magnetic pole is composed of the above-mentioned comb-teeth shape, the magnetic flux passing between the inner magnetic pole and the outer magnetic pole is the inner side obtained by projecting the comb-teeth-shaped outer magnetic pole and outer magnetic pole onto the cylindrical inner magnetic pole. The shape of the inner magnetic pole may be a simple hollow cylindrical shape because it passes between the magnetic pole and the position above the magnetic pole.

The outer magnetic poles 18a, 18b and the inner magnetic poles 18c, 18d of the stator 18 are provided so as to sandwich the one end side of the magnet 1 so as to face the outer peripheral surface and the inner peripheral surface of the magnet 1 on one end side. Also, the holes 18 of the stator 18
One end of the pin 20b of the cover 20 is fitted in e.

Therefore, the magnetic flux generated by the coil 2 is the outer magnetic poles 18a, 18b and the inner magnetic poles 18c, 18.
Since it traverses the magnet 1 which is a rotor between the magnet and d, it effectively acts on the magnet which is a rotor to increase the output of the motor.

Further, as shown in FIG. 2, the stator 18 is provided with a hole 18i through which an air flow flows.

As the material of the magnet 1, a plastic magnet formed by injection molding a mixture of Nd-Fe-B rare earth magnetic powder and a thermoplastic resin binder material such as polyamide is used. As a result, the bending strength of the compression molded magnet is 500
Against kgf / cm ² degree of, for example, a polyamide resin 800 kgf / cm ² or more bending strength can not be a compression molding obtained when used as a binder material, it can be formed a thin cylindrical shape. Due to the thin cylindrical shape, the outer magnetic poles 18a and 18b of the stator 18 are
The distance between the inner magnetic poles 18c and 18d can be made very small, and the magnetic resistance of the magnetic circuit formed by the coil 2 and the first stator can be made small. As a result, a large amount of magnetic flux can be generated with a small amount of current, increasing the motor output,
Lower power consumption and smaller coil size will be achieved.

Further, by using the above-mentioned material as the material of the magnet 1, the shape can be freely set and sufficient strength of the fitting portion 1e can be obtained. Since the slidable fitting portion 1e of the magnet 1 is integrally formed with the magnet 1, coaxial accuracy of the magnet portion with respect to the center of rotation is improved, vibration is reduced, and the gap distance between the magnet and the stator portion is increased. Can be reduced, and a sufficient output torque of the motor can be obtained.

Further, since the injection-molded magnet has a thin resin film formed on the surface thereof, the generation of rust is much less than that of the compression magnet, so that the rust prevention treatment such as painting can be eliminated. In addition, there is no adhesion of magnetic powder, which is a problem with compression magnets, and there is no bulging of the surface that tends to occur during rust-preventive coating, and quality can be improved.

Reference numeral 20 denotes a cylindrical cover made of a non-magnetic material. The outer magnetic poles 18a and 18b of the stator 18 are fitted into the inner diameter portion of the cover 20 and fixed with an adhesive or the like. Further, the pin 20b is slidably fitted to the fitting portion 1e of the magnet 1. The air flow generated by the rotation of the fan 7 enters from the air holes 18i of the stator 18 and is indicated by an arrow A.
The cover 20 is cooled by flowing in a direction and passing through the window 20c of the cover 20.

Reference numeral 8 denotes a known electronic component to be cooled, which is in contact with the cover 20. The heat generated from the electronic component 8 is transferred to the cover 20 and cooled by the air flow generated by the rotation of the fan 7. It

FIG. 2 is a sectional view of the fan motor, and the fan 7 is omitted for simplification. 3, 4, 5,
FIG. 6 shows a sectional view taken along the line AA of FIG. 3, Q1 represents the center of the outer magnetic pole 18a of the stator 18, Q2 represents the center of the outer magnetic pole 18b of the stator 18, and Q3 represents the center of rotation of the magnet 1.

FIG. 7 shows the rotational position of the magnet and the manner in which the magnet is attracted by the outer magnetic pole when the coil is not energized. The vertical axis represents the magnetic force generated between the magnet and the stator 18 acting on the magnet, and the horizontal axis represents the rotational phase of the magnet. At the point indicated by point E in this figure, a negative force acts when trying to rotate, trying to return to the original position, and a force working in the direction of going backward when returning, that is, it is returned to the original position This is the position of the coking, which is about to be stably positioned at the point E by the magnetic force between the outer magnetic poles. Point F is an unstable equilibrium stop position where the driving force acts on the points E before and after even a slight deviation. When the coil is not energized, it does not stop at point F due to vibration or changes in posture, but stops at the position of point E.

As a result of the numerical simulation by the finite element method, the outer magnetic poles 18a and 18b and the magnet 1 when the coil is not energized depend on the relationship between the angle of the magnetized pole and the angle of the outer magnetic pole opposite to it. It became clear that the state of the suction state changed. According to this, the coking position of the magnet changes depending on the angle of the outer magnetic pole facing the magnet. That is, when the angle of the outer magnetic pole facing the magnet is larger than a certain value, the boundary between the magnet poles is stably held at a position facing the center of the outer magnetic pole. The point E shown in FIG. 7 is the position where the boundary between the poles of the magnet faces the center of the outer magnetic pole. On the contrary, when the angle of the outer magnetic pole facing the magnet is smaller than a certain value, the center position of the pole of the magnet is stably held at the position facing the center of the outer magnetic pole. Figure 7
The point E is the position where the center of the magnet pole faces the center of the outer magnetic pole.

This state is shown in detail in FIG. The horizontal axis is (magnet thickness / outer peripheral length per magnet pole), and the vertical axis is (angle facing the magnet per outer magnetic pole / magnet 1).
The angle per pole). For example, when the outer diameter of the magnet is 10 mm, the inner diameter is 9 mm, and the number of poles is 20, the thickness of the magnet is (outer diameter-inner diameter) / 2, and the magnetic pole 1
Since the outer circumference length per pole is 10 × π / 20, the value of (magnet thickness / outer circumference length per pole of magnet) on the horizontal axis is 0.
It becomes 318. Further, assuming that the facing angle of each outer magnetic pole with respect to the magnet is 15 degrees, the angle per magnet pole is 18 degrees, so that the vertical axis is (angle of facing outer magnet per outer pole / angle per magnet pole). ) Becomes 0.833.

Each point in FIG. 8 is a plot of (a facing angle with respect to a magnet per one outer magnetic pole / an angle per one magnet) in which the coking torque is substantially zero. If the vertical axis is Y and the horizontal axis is X, these points can be approximated by the equation of straight line Y = 0.327X + 0.69. If Y> -0.327X + 0.69, the boundary between the magnet poles is stably maintained at the position facing the center of the outer magnetic pole, and if Y <-0.327X + 0.69, the center position of the magnet pole is the outer magnetic pole. It is stably held at a position facing the center of the.

That is, Y> -0.327X + 0.69 is expressed as follows. Assuming that the facing angle of each of the outer magnetic poles is A degrees, the outer diameter dimension D1 of the magnet and the inner diameter dimension D2 of the magnet are A> (248.4 / N) -58.86.
× (D1-D2) / (D1 × π). A> (248.4 /
N) -58.86 × (D1-D2) / (D1 × π) is set so that the boundary between the poles of the magnet is stably held at the position facing the center of the outer magnetic pole. .

In the case of the present embodiment, the number of magnetic poles N is 4, so that, for example, if the outer diameter dimension D1 of the magnet is 10 mm and the inner diameter dimension D2 of the magnet is 9 mm, (248.4 /
N) −58.86 × (D1−D2) / (D1 × π) = 60.2
It becomes 3 degrees, and if the facing angle A of each outer pole with respect to the magnet exceeds 60.23 degrees, Y> -0.327X
This applies to the condition of +0.69. In this embodiment, the facing angle A of each outer magnetic pole with respect to the magnet is 90 degrees, so that the boundary between the poles of the magnet is stably held at a position facing the center of the outer magnetic pole. -ing

When the boundary between magnetized poles of the magnet is at a position facing the center of the comb tooth of the outer magnetic pole portion, the coil 1 is energized to excite the comb tooth of the outer magnetic pole portion without fail. Is activated by a rotating force. However, when the center of the magnetized pole of the magnet is at the position facing the center of the comb tooth of the outer magnetic pole portion, even if the comb tooth of the outer magnetic pole portion is excited by energizing the coil, the magnet 1
Does not generate rotational force, so smooth startup cannot be performed.

In this embodiment, the angle of the outer magnetic poles 18a, 18b facing the magnet 1 is A degree, and the outer diameter dimension D of the magnet.
1. If the inner diameter of the magnet is D2, A> (248.4
/N)-58.86 x (D1-D2) / (D1 x π), the values are set so that it corresponds to the case above the portion shown by the straight line in FIG. Therefore, when the coil is not energized, the point E is located at the position where the boundary between the magnetized poles of the magnet faces the center of the comb teeth of the outer magnetic pole portion, so it can be stably stopped at this position. is doing. In this state, when the coil is energized to excite the comb teeth of the outer magnetic pole portion, the magnet 1 always generates a rotational force and a smooth start is performed. The outer magnetic pole has the above-described dimensions, and when the coil is not energized, the magnet 1
That is, the center of each pole of the magnetized portion serves as a holding unit that holds the position at a position deviated from the straight line connecting the center of the outer magnetic pole and the center of rotation of the magnet.

Next, the operation of the fan motor will be described. A>
(248.4 / N) -58.86 x (D1-D2) / (D1 x
Since the dimensions of each part are set so as to be (π), the centers of the respective poles of the magnetized portion of the magnet 1 of the outer magnetic pole portions 18a and 18b are the center of the outer magnetic pole when the coils are not energized. Since it functions as a holding means for holding the coil 2 at a position deviated from a straight line connecting the rotation center of the magnet, the magnet 1 is not energized when the coil 2 is de-energized.
The boundary between the magnetized portions is in a state as shown in FIG. 3 where the boundary faces the centers of the outer magnetic poles 18a and 18b.

When the coil 2 is energized from the state shown in FIG. 3 to make the outer magnetic poles 18a and 18b of the stator 18 N pole and the inner magnetic poles 18c and 18d S pole, the outer magnetic pole 18 is excited.
Due to the excitation of the magnets a, 18b and the inner magnetic poles 18c, 18d, the magnet 1 always receives the electromagnetic force in the rotation direction, and the magnet 1 as the rotor starts to rotate counterclockwise smoothly. Then, the power supply to the coil 2 is cut off at the timing shown in FIG. Since the state shown in FIG. 4 is point F in FIG. 7, the rotor inertia further rotates counterclockwise from the state shown in FIG. 4 toward the next point E. Then, the state shown in FIG. 5 becomes stable due to the cogging force.

Next, when the energization to the coil 2 is reversed and the outer magnetic poles 18a and 18b of the stator 18 are made to be S poles and the inner magnetic poles 18c and 18d are made to be N poles, the magnet 1 as a rotor is further rotated counterclockwise. It rotates and rotates toward the state shown in FIG. After that, by sequentially switching the energization direction to the coil 2 in this manner, the magnet 1 as the rotor rotates to a position corresponding to the energization phase.

In the above structure, the diameter of the motor is determined by the outer magnetic poles that face the outer peripheral surface of the magnet, and the axial length of the motor is determined by arranging the coil and the magnet in that order, which greatly reduces the size of the motor. You can do things. Further, since the magnetic flux generated by the coil traverses the magnet between the outer magnetic pole and the inner magnetic pole, the magnetic flux acts effectively, so that an efficient motor can be obtained. Since the fan that rotates integrally with the magnet is arranged inside the inner diameter of the magnet, the size of the motor itself does not increase. Further, since the fan can be configured near the center of the motor, even if a small electronic component is arranged near the center of rotation of the motor, it can be cooled efficiently.

Further, the portion of the magnet that is the source of the torque is the outer diameter of the magnet, so that the motor can generate a large torque.

Here, it will be described that the fan motor having such a structure is an optimum structure for miniaturizing the motor. The basic structure of the fan motor will be described. First, the magnet is formed in a hollow cylindrical shape, and secondly, the outer peripheral surface of the magnet is divided into n in the circumferential direction and magnetized to different poles alternately. Thirdly, the coils are arranged side by side in the axial direction of the magnet, and fourthly, the outer magnetic poles and inner magnetic poles of the stator excited by the coils are opposed to the outer peripheral surface and the inner peripheral surface of the magnet. Fifth, the outer magnetic pole is composed of a notch hole and teeth extending in the direction parallel to the shaft. Sixth, when the coil is not energized, the center of the pole of the magnet is rotated with respect to the center of the outer magnetic pole and the rotation of the magnet. That is, it is provided with a holding means for holding at a position deviated from the straight line connecting the center.

The diameter of this fan motor should be large enough to make the magnetic poles of the stator face the diameter of the magnet, and the length of the fan motor should be just the length of the magnet plus the length of the coil. It would be good if there was a length.
Therefore, the size of the fan motor is determined by the diameter and length of the magnet and the coil, and the fan motor can be made extremely small by making the diameter and the length of the magnet and the coil extremely small. .

At this time, if the diameter and the length of the magnet and the coil are made extremely small, it becomes difficult to maintain the accuracy as a fan motor. This is because the magnet is formed in a hollow cylindrical shape. The problem of accuracy of the fan motor is solved by a simple structure in which the outer magnetic pole and the inner magnetic pole of the stator are opposed to the outer peripheral surface and the inner peripheral surface of the cylindrical magnet. At this time, not only the outer peripheral surface of the magnet but also the inner peripheral surface of the magnet are circumferentially divided and magnetized, so that the output of the motor can be further increased.

Assuming that the facing angles A of the comb teeth of the outer magnetic pole portion facing the outer peripheral portion of the magnet are A, the outer diameter dimension D1 of the magnet and the inner diameter dimension D2 of the magnet are A> (24
8.4 / N) -58.86 × (D1-D2) / (D1 × π) so that the boundary between the magnetized poles of the magnet is the comb teeth of the outer magnetic pole portion. The magnetic force generated from the coil acts on the magnet when the motor is stopped and the coil is first energized after the motor is stopped, so that the rotation can be stably started without going to the rotation center of the magnet. Since the magnet and the outer magnetic pole are used as means for setting the initial position of the magnet to a position where the rotation can be stably activated, the cost can be reduced.

Since one coil is used, the energization control circuit can be simplified and the cost can be reduced.

(Embodiment 2) FIGS. 9 to 15 are views showing Embodiment 2 of the present invention, FIG. 9 is an exploded perspective view of a motor according to an embodiment to which the present invention is applied, and FIG. FIG. 11 is a vertical cross-sectional view of the motor of FIG. 9, FIG. 11 is a plan view showing a relationship between a stator and a coil, and FIG. 12 shows a state in which a motor to which the present invention is applied is in a certain rotational position of a magnet and a stator. FIG. 13 is a plan view showing the relationship, FIG. 13 is a plan view showing the relationship between the magnet and the stator when the motor to which the present invention is applied is rotated by a predetermined angle in the arrow direction from the state of FIG. 12, and FIG. FIG. 15 is a plan view showing the relationship between the magnet and the stator when the motor to which the present invention is applied is rotated by a predetermined angle in the arrow direction from the state of FIG. 13, and FIG. From the predetermined angle in the direction of the arrow FIG. 6 is a plan view showing the relationship between the magnet and the stator in a state where the magnet and the stator are rotated only by a right angle.

In FIGS. 9 to 15, reference numeral 21 denotes a rotor, which comprises a shaft portion and a cylindrical magnet portion made of a permanent magnet. In this magnet portion, the outer peripheral surface is divided into n in the circumferential direction (16 in this embodiment), and S poles and N poles are alternately magnetized. The shaft portion and the cylindrical magnet portion may be integrally formed, or they may be integrally formed by adhesion or press fitting.

The outer peripheral surface of the magnet portion is divided into n in the circumferential direction (16 divisions in this embodiment), and magnetized portions 21a, 21b, 21c and 21 are magnetized so that S poles and N poles are alternately magnetized.
d, 21e, 21f, 21g, 21h, 21i, 21
j, 21k, 21m, 21n, 21p, 21q, 21r
Are formed. Here, the magnetizing portions 21a, 21
c, 21e, 21g, 21i, 21k, 21n, 21q
Is magnetized to the S pole, and the magnetized portions 21b, 21d, 21
f, 21h, 21j, 21m, 21p and 21r are magnetized to the N pole.

The magnet section is made of a plastic magnet material formed by injection molding or the like. As a result, the cylindrical radial thickness can be made very thin. The inner peripheral surface of the magnet part has a weaker magnetization distribution than the outer peripheral surface, or is not magnetized at all, or the pole opposite to the outer peripheral surface, that is, when the outer peripheral surface is the S pole, the inner peripheral surface of the range. The surface is either magnetized to the N pole.

A fan 27 is formed inside the cylindrical portion of the magnet, and the fan 27 may be integrally formed with the magnet 21 or may be integrally formed by bonding.

The shafts 21s and 21t are the cover 2 which will be described later.
5 and the fitting hole 22h of the stator 22 are rotatably fitted.

Reference numeral 22 is a stator made of a soft magnetic material. The stator 22 has an outer cylinder and an inner cylinder, and the shaft portion 21t of the rotor 21 is rotatably fitted therein. And
At the tip of the outer cylinder of the stator 22, there are three first outer magnetic pole portions 22a which are notched in the cylinder and have a tooth shape extending in the direction parallel to the axis, and which face the outer peripheral surface of the magnet portion of the rotor 21.
Similarly to 22b and 22c, the three second outer magnetic pole portions 22d and 22e, which face the outer peripheral surface of the magnet portion of the rotor,
22f is formed. The first outer magnetic pole portions 22a, 22b, 22c of the stator 22 are an integral multiple of 360 / (n / 2) degrees, that is, θ so that they have the same phase as the magnetization phase.
It is formed by being shifted from each other by an integral multiple of 1 = 45 degrees.
The range in which the first outer magnetic pole portions 22a, 22b, 22c are opposed to the outer peripheral surface of the magnet portion of the rotor is referred to in the claims.
It is a predetermined range of 1.

The second outer magnetic pole portion 22 of the stator 22
d, 22e, and 22f are integer multiples of 360 / (n / 2) degrees, that is, θ2 = 4, so that they are in phase with the magnetization phase.
They are formed so that they are shifted by an integral multiple of 5 degrees. The first outer magnetic pole and the second outer magnetic pole as a whole are θ3 = (180 / n
+ A × 360 / n) degree or (11.25 + 22.5)
× A) It is arranged with a deviation. Where A is an integer. In this embodiment, θ3 = 101.25 degrees. The first outer magnetic pole and the second outer magnetic pole are overlapped in the range facing the rotor in the direction parallel to the axial direction of the rotor. That is, each magnetized part of the magnet part of the rotor is
It comes to a position facing the first outer magnetic pole or comes to a position facing the second outer magnetic pole.

The second outer magnetic pole portions 22d, 2 of the stator 22
The range in which 2e and 22f face the outer peripheral surface of the magnet portion of the rotor is the second predetermined range in the claims. As shown in the figure, the first predetermined range and the second predetermined range are at different positions.

The stator 22 is composed of a single member,
The first outer magnetic pole portions 22a, 22b, 22c and the second outer magnetic pole portions 22d, 22e, 22f are integrally configured. Therefore, the first outer magnetic pole portions 22a, 22b, 22c
And the second outer magnetic pole portions 22d, 22e, 22f are suppressed from being small in error, and variations in motor performance due to assembly can be suppressed to be small.

The inner cylindrical portion 22g constitutes an inner magnetic pole portion facing the inner peripheral surface of the magnet portion of the rotor 21. The fitting hole 22h is rotatably fitted in the shaft portion 21t of the rotor 21.

The magnet portion of the rotor 21 is sandwiched between the inner magnetic pole portion composed of the inner cylindrical portion 22g, the first outer magnetic pole portions 22a, 22b and 22c and the second outer magnetic pole portions 22d, 22e and 22f. In the present embodiment, the inner cylindrical portion 2 is further
2g is also integrally formed with the first outer magnetic pole portions 22a, 22b, 22c and the second outer magnetic pole portions 22d, 22e, 22f. Therefore, the first outer magnetic pole portions 22a, 22
The mutual difference between b and 22c and the inner magnetic pole portion and the mutual error between the second outer magnetic pole portions 22d, 22e and 22f and the inner magnetic pole portion can be suppressed to be small, and variation in motor performance due to assembly can be suppressed to be small.

Reference numeral 23 is a first coil, which is a first outer magnetic pole portion 2.
The first outer magnetic pole portions 22a, 22b, 22 are wound around the second magnetic pole portions 2a, 22b, 22c and are energized.
A part of the inner cylindrical portion 22g, which is the inner magnetic pole portion facing the c and the first outer magnetic pole portions 22a, 22b, 22c, is excited. Of course, in this case, the first outer magnetic pole portion and the inner magnetic pole portion opposed thereto are excited by different poles.

A second coil 24 is a second outer magnetic pole portion 2
The second outer magnetic pole portions 22d, 22e, 22 are wound around 2d, 22e, 22f and are energized to energize them.
Part of the inner cylindrical portion 22g, which is the inner magnetic pole portion facing the f and the second outer magnetic pole portions 22d, 22e, and 22f, is excited. Of course, in this case, the second outer magnetic pole portion and the inner magnetic pole portion facing it are excited to different poles.

The inner cylindrical portion 22g is composed of the first outer magnetic pole portion 22a,
22b and 22c and the second outer magnetic pole portion 22
d, 22e, and 22f are independently excited by the first coil 23 and the second coil 24. The first outer magnetic pole portion 22 excited by the first coil 23
The portion facing a, 22b, 22c will be referred to as the first inner magnetic pole from now on, and the second magnetic field excited by the second coil 24 will be referred to as the second inner magnetic pole.
The portion facing the outer magnetic pole portions 22d, 22e, 22f will be hereinafter referred to as the second inner magnetic pole. The first inner magnetic pole and the second inner magnetic pole may be integrally formed as in the present embodiment, or may be separately formed, or the first outer magnetic pole portion 22.
a, 22b, 22c or the second outer magnetic pole portions 22d, 2
2e and 22f may have a tubular shape with a notch and may be configured as a tooth extending in a direction parallel to the axis.

The first outer magnetic pole portions 22a, 2 of the stator 2
2b, 22c or the second outer magnetic pole portions 22d, 22e,
22f is a notch in the cylinder and is constituted by teeth extending in a direction parallel to the motor shaft along the outer peripheral surface of the stator.
The diameter of the motor can be minimized. If the outer magnetic pole portion is formed by unevenness extending in the radial direction, the diameter of the motor will increase accordingly.

The first outer magnetic pole portions 22a, 2 of the stator 2
The first inner magnetic poles 2b and 22c and a part of the inner cylindrical portion 22g are formed to face the outer peripheral surface and the inner peripheral surface of the magnet portion of the rotor 21 and sandwich the magnet portion.
The second outer magnetic pole portion 22d, 22e, 22f and the inner tubular portion 2
A part of the second inner magnetic pole 2g is formed so as to face the outer peripheral surface and the inner peripheral surface of the magnet portion of the rotor 21 and to sandwich the magnet portion. By energizing the first coil 23, the first outer magnetic pole portions 22a, 22b, 22c and
The inner magnetic pole 1 is excited, but the magnetic flux generated during that crosses the magnet portion of the rotor 21, so that it effectively acts on the magnet. Similarly, by energizing the second coil 24, the second outer magnetic pole portions 22d, 22e, 22f
The second inner magnetic pole is excited, but the magnetic flux generated between the second inner magnetic pole traverses the magnet portion of the rotor 21 and effectively acts on the magnet.

Furthermore, since the magnet portion of the rotor 21 is made of a hollow cylindrical plastic magnet material formed by injection molding as described above, the radial thickness of the cylindrical shape can be made very thin. it can.

Therefore, the first outer magnetic pole portions 22a, 22
The distance between b and 22c and the first inner magnetic pole and the distance between the second outer magnetic pole portions 22d, 22e and 22f and the second inner magnetic pole can be made very small, and the first coil 23 and the first outer magnetic pole can be formed. The magnetic circuit formed by the portions 22a, 22b, 22c and the first inner magnetic pole, the second coil 24, the second outer magnetic pole portions 22d, 22e, 22f and the magnetic circuit formed by the second inner magnetic pole. The resistance can be reduced.
As a result, a large amount of magnetic flux can be generated with a small amount of current, and the output of the motor can be increased, the power consumption can be reduced, and the size of the coil can be reduced.

The first coil 23 and the first outer magnetic pole portion 22
The magnetic flux generated in the magnetic circuit formed by a, 22b, 22c and the first inner magnetic pole acts on the magnet portion of the rotor 21, and the second coil 24 and the first outer magnetic pole portions 22d, 22e, 22f. The magnetic flux generated in the magnetic circuit formed by the second inner magnetic pole acts on the magnet portion of the rotor 21, and as the rotor rotates, the magnets used in the respective magnetic circuits are the same. Therefore, it is configured to use the exact same range. Since exactly the same parts of the magnet part of the rotor are used, it is possible to obtain a motor having stable performance without being adversely affected by variations due to magnetization.

According to the above structure, the magnetic flux generated by energizing the first coil is located between the first outer magnetic pole and the first inner magnetic pole, and the outer peripheral surface is divided in the circumferential direction into different poles. The magnetic flux that effectively acts on the magnet portion of the rotor 21 which is a hollow cylindrical portion that is alternately magnetized and is generated by energizing the second coil is generated between the second outer magnetic pole and the second inner magnetic pole. Since the outer peripheral surface is divided in the circumferential direction and is effectively magnetized to the magnet portion of the rotor, which is a hollow cylindrical portion that is magnetized alternately to different poles, the rotation output of the magnet that is the rotor increases. . In other words, it can be a compact but high-output actuator. Further, the first outer magnetic pole and the second outer magnetic pole are configured to face the same rotor in different angular ranges, and are arranged so that their positions in the axial direction and the parallel direction of the rotor overlap. Since the rotor can be configured to be short in the axial direction, the motor can also be short in the length in the parallel direction to the axial direction.

Reference numeral 25 denotes a cover made of a non-magnetic material, the inner peripheral portion of which is the first outer magnetic pole portions 22a, 22b, 2 of the stator 22.
2c and the second outer magnetic pole portions 22d, 22e, 22f are attached to the outer peripheral surfaces, and the fitting hole 25a is provided in the shaft portion 2 of the rotor 21.
1s is rotatably fitted.

The air flow generated by the rotation of the fan 27 enters from the air holes 22i of the stator 22, flows in the direction of arrow A, and escapes to the window 25c of the cover 25,
Is cooled.

As in the first embodiment, the heat generated from the parts to be cooled, such as electronic parts (not shown), which are in contact with the cover 25, is transferred to the cover 25 and cooled by the airflow generated by the rotation of the fan 27. To be done.

Next, the operation of the step motor according to the second embodiment of the present invention will be described with reference to FIGS. In FIG. 12, the stator 22 is energized by energizing the first coil 23.
The first outer magnetic pole portions 22a, 22b, 22c are N poles, and the first outer magnetic pole portions 22a,
It is a state in which the inner magnetic pole portion facing 2b and 22c, that is, the first inner magnetic pole portion is excited so as to become the S pole. In this state, the second coil is not energized.

From the state shown in FIG. 12, the direction of energization to the first coil 23 is cut off, and at the same time, the second coil 24 is energized to make the second outer magnetic pole portions 22d, 22e, 22f of the stator 22 N pole, and The second outer magnetic pole portion 22 is a part of the cylindrical portion 22g.
When the inner magnetic pole portion facing d, 22e, 22f, that is, the second inner magnetic pole portion is excited so as to become the S pole, the rotor 21 rotates counterclockwise by 11.25 degrees as shown in FIG.

The energization direction to the second coil 24 is cut off from the state shown in FIG. 13, and at the same time, the first coil 23 is energized in the direction opposite to the state shown in FIG. 12, that is, the first outer magnetic pole portions 22a, 22.
b and 22c are S poles, and the inner magnetic pole portion facing the first outer magnetic pole portions 22a, 22b and 22c by a part of the inner cylindrical portion 22g, that is, the first inner magnetic pole portion is excited to be an N pole.
The rotor 21 is further rotated counterclockwise by 11.2
Rotate 5 degrees.

The energization direction to the first coil 23 is cut off from the state shown in FIG. 14, and at the same time, the second coil 24 is energized in the direction opposite to the state shown in FIG. 13, that is, the second outer magnetic pole portions 22d, 22.
1e and 22f are S poles, and the inner magnetic pole portion facing the 22nd outer magnetic pole portions 22d, 22e, 22f at a part of the inner cylindrical portion 22g, that is, the second inner magnetic pole portion is excited to be an N pole.
As shown in FIG. 5, the rotor 21 is further rotated counterclockwise by 11.2.
Rotate 5 degrees.

After that, the rotor 21 is rotated to the position corresponding to the energization phase by sequentially switching or interrupting the energization directions of the first coil 23 and the second coil 24 in this way. become.

Here, it will be described that the motor as described above has an optimum configuration for making the motor extremely small. According to the above configuration, since the magnetic flux generated by the first coil 23 and the second coil 24 crosses the magnet portion of the rotor between the outer magnetic pole portion and the inner magnetic pole portion, the magnetic flux acts effectively. It becomes possible to improve the motor output.

Further, the first outer magnetic pole and the second outer magnetic pole are
Since the rotor is configured to face the same rotor in different angular ranges, the rotor can be configured to be short in the axial direction, and thus the motor can be configured to have a short length in the axial direction and the parallel direction.

The first coil 23 and the first outer magnetic pole portion 22
The magnetic flux generated in the magnetic circuit formed by a, 22b, 22c and the first inner magnetic pole acts on the magnet portion of the rotor 21, and the second coil 24 and the first outer magnetic pole portions 22d, 22e, 22f. The magnetic flux generated in the magnetic circuit formed by the second inner magnetic pole acts on the magnet portion of the rotor 21, and as the rotor rotates, the magnets used in the respective magnetic circuits are the same. Therefore, it is configured to use the exact same range. Since exactly the same parts of the magnet part of the rotor are used, it is possible to obtain a motor having stable performance without being adversely affected by variations due to magnetization.

Further, the rotor 21 is provided with shaft portions 21s and 21t and is rotatably held in this portion.
Since the outer magnetic pole portion 1 and the second outer magnetic pole portion are constituted by the pole teeth extending in the direction parallel to the motor shaft, the substantial volume occupied by the motor drive portion, that is, between the outer diameter and the inner diameter of the motor. The volume (width dimension of the donut shape) can be minimized. If the outer magnetic pole portion is formed by the unevenness extending in the radial direction, the volume occupied by the motor, that is, the volume between the outer diameter and the inner diameter of the motor increases, but in the motor according to the present embodiment to which the present invention is applied, Since the outer magnetic pole portion is formed by the teeth extending in the direction parallel to the motor shaft, the volume occupied by the motor, that is, the volume between the outer diameter and the inner diameter of the motor can be minimized.

According to the above structure, the magnetic flux generated by energizing the first coil is located between the first outer magnetic pole and the first inner magnetic pole, and the outer peripheral surface is divided in the circumferential direction into different poles. The magnetic flux effectively acting on the magnets alternately magnetized and generated by energizing the second coil is located between the second outer magnetic pole and the second inner magnetic pole, and the outer peripheral surface is divided in the circumferential direction. As a result, the magnets that are magnetized alternately on different poles are effectively acted on, so that the rotational output of the magnet is increased.

Further, the first outer magnetic pole and the second outer magnetic pole are
Since the same magnet is configured to face each other in different angular ranges, the magnet can be configured to be short in the axial direction, and the motor can be configured to have a short length in the axial direction and the parallel direction.

As in the first embodiment, since the fan that rotates integrally with the magnet is arranged inside the inner diameter of the magnet, the size of the motor itself does not increase. Further, since the fan can be configured near the center of the motor, even if a small electronic component is arranged near the center of rotation of the motor, it can be cooled efficiently. Further, the portion of the magnet that is the source of torque is the outer diameter of the magnet, so that the motor can generate a large torque.

Further, since the first outer magnetic pole, the first inner magnetic pole, the second outer magnetic pole, and the second inner magnetic pole are excited by energizing the two coils, stable rotation can be obtained.

[0090]

As described above in detail, according to the present invention,
A magnet having a cylindrical shape, at least the outer peripheral surface of which is divided in the circumferential direction and which is alternately magnetized to different poles and rotatable about a rotation center, is provided with a coil arranged in the axial direction of the magnet. An outer magnetic pole portion that is excited by the magnet and faces the outer peripheral surface of the magnet, a hollow pillar-shaped inner magnetic pole portion that is excited by the coil and faces the inner peripheral surface of the magnet, and is integrally formed with the magnet on the inner diameter portion of the magnet. Since it is characterized by having a fan arranged, a fan motor having a completely new structure different from the conventional one can be obtained, and an optimum structure can be obtained in order to make the fan motor extremely small.

In the above construction, the diameter of the fan motor is determined by the outer magnetic poles facing the outer peripheral surface of the magnet, and the axial length of the motor is determined by arranging the coil and the magnet in that order, and the motor is made extremely compact. It is something you can do. Further, since the magnetic flux generated by the coil traverses the magnet between the outer magnetic pole and the inner magnetic pole, the magnetic flux acts effectively, so that an efficient fan motor can be obtained.

Since the fan that rotates integrally with the magnet is arranged in the inner diameter portion of the hollow pole-shaped inner magnetic pole portion, the size of the fan motor itself does not increase. Further, since the fan can be configured near the center of the motor, even if a small electronic component is arranged near the center of rotation of the motor, it can be cooled efficiently.

Further, since the portion of the magnet that is the source of the torque is the outer diameter of the magnet, it can be a fan motor that produces a large torque.

Further, a magnet which is formed in a cylindrical shape and at least the outer peripheral surface of which is divided into N in the circumferential direction and which is alternately magnetized to different poles and rotatable about a rotation center is provided, and the coil is arranged in the axial direction of the magnet. Placed on the outer peripheral surface of the magnet (720 /
N) degrees, each of which is a comb-teeth-shaped outer magnetic pole portion provided to face each other by a predetermined angle A, and a hollow pillar shape which is excited by the coil and faces the inner peripheral surface of the magnet. Of the inner magnetic pole part, and a weight arranged in the space of the inner diameter part of the hollow cylindrical part of the inner magnetic pole part, which is configured to rotate integrally with the magnet and has an unbalanced mass with respect to the center of rotation. And the comb-shaped facing angles A of the outer magnetic pole portion facing the outer peripheral portion of the magnet.
Degree, magnet outer diameter dimension D1, magnet inner diameter dimension D
If it is 2, A> (248.4 / N) −58.86 × (D1−
Since it is set to be (D2) / (D1 x π), the fan motor can be configured optimally for miniaturization.

That is, the diameter of the fan motor only needs to be large enough to make the magnetic poles of the stator face the diameter of the magnet, and the length of the fan motor is simply the length of the magnet plus the length of the coil. It would be good if there was a length.
Therefore, the size of the fan motor is determined by the diameter and length of the magnet and the coil, and the fan motor can be made extremely small by making the diameter and the length of the magnet and the coil extremely small. . Since the fan that rotates integrally with the magnet is arranged in the inner diameter portion of the hollow pole-shaped inner magnetic pole portion, the size of the fan motor itself does not increase. Further, since the fan can be configured near the center of the motor, even if a small electronic component is arranged near the center of rotation of the motor, it can be cooled efficiently.

Further, since the portion of the magnet that is the source of the torque is the outer diameter of the magnet, it can be a fan motor that produces a large torque.

The boundary between magnetized poles of the magnet is positioned at the center of the comb teeth of the outer magnetic pole portion, and the magnetic flux generated from the coil acts on the magnet when the motor is stopped and the coil is first energized. The force to do so does not go to the center of rotation of the magnet, and the rotation can be stably started. As described above, since the magnet and the outer magnetic pole are used as means for setting the initial position of the magnet to the position so that the rotation can be stably activated, the cost can be reduced.

Further, the magnet 1 is made of the plastic magnet material formed by injection molding as described above, whereby the thickness of the cylindrical shape in the radial direction can be made very thin.

Therefore, the outer magnetic poles 18a of the stator 18 are
The distance between 18b and the inner magnetic poles 18c and 18d can be made very small, and the magnetic resistance of the magnetic circuit formed by the coil 2 and the stator can be made small. As a result, a large amount of magnetic flux can be generated with a small amount of current, increasing the motor output
Lower power consumption and smaller coil size will be achieved.
In particular, a plastic magnet formed by injection molding a mixture of Nd-Fe-B rare earth magnetic powder and a thermoplastic resin binder material such as polyamide is used as the material of the magnet 1. As a result, the bending strength of the compression molded magnet is 500 Kgf / cm ²
On the other hand, when a polyamide resin is used as a binder material, for example, a bending strength of 800 Kgf / cm ² or more is obtained, and a thin-walled cylindrical shape that cannot be obtained by compression molding can be formed. As described above, the thin cylindrical structure improves the performance of the motor because the distance between the outer magnetic pole and the inner magnetic pole can be set short and a large magnetic flux can be generated by a small magnetomotive force.

Further, since the injection-molded magnet has a thin resin film formed on the surface thereof, the generation of rust is significantly less than that of the compression magnet, so that the rust prevention treatment such as painting can be eliminated.

[Brief description of drawings]

FIG. 1 is an exploded perspective view of a motor according to the present invention.

FIG. 2 is a sectional view of the motor shown in FIG. 1 in a completed assembled state.

FIG. 3 is an explanatory diagram of a rotation operation of a rotor of the motor shown in FIG.

4 is an explanatory diagram of a rotation operation of a rotor of the motor shown in FIG.

5 is an explanatory diagram of a rotation operation of a rotor of the motor shown in FIG.

FIG. 6 is an explanatory diagram of a rotation operation of a rotor of the motor shown in FIG.

FIG. 7 is a graph showing the state of cogging torque.

FIG. 8 is a graph showing the relationship between the width dimension of the outer magnetic pole, the coking torque, and the magnet dimension.

FIG. 9 is an exploded perspective view of a motor according to a second embodiment of the present invention.

10 is a vertical cross-sectional view of the motor shown in FIG.

FIG. 11 is a plan view showing a relationship between a stator and a coil.

FIG. 12 is a cross-sectional view showing the relationship between the magnet portion and the stator of the rotor 1 when the motor according to the embodiment of the present invention is in a certain rotational position.

13 is a cross-sectional view showing the relationship between the magnet unit and the stator when the motor according to the embodiment of the present invention is rotated counterclockwise from the state of FIG. 12 by a predetermined angle.

FIG. 14 is a cross-sectional view showing the relationship between the magnet unit and the stator when the motor according to the embodiment of the present invention is rotated counterclockwise from the state of FIG. 13 by a predetermined angle.

15 is a cross-sectional view showing the relationship between the magnet unit and the stator when the motor according to one embodiment of the present invention is rotated counterclockwise from the state of FIG. 14 by a predetermined angle.

FIG. 16 is a sectional view of a conventional fan motor.

[Explanation of symbols]

1 rotor 2 coils 18 Stator 20 cover 21 magnet 22 Stator 23 coils 24 coils 25 covers

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI Theme Coat (reference) H02K 1/14 H02K 1/14 C 5H621 1/27 501 1/27 501A 5H622 7/14 7/14 AF Term (reference) 3H022 AA02 BA03 CA06 CA49 CA50 DA03 3H034 AA02 AA11 BB02 BB06 BB20 CC05 DD28 EE03 3H035 AA04 AA06 5H002 AA01 AB01 AB04 AE02 5H607 AA12 BB01 J07KJK17J07K07J07K07J07K07J07K07JH17BB02 CC01 DD05DD05 DD05 DD05 DD05DD05 DD05 DD05DD05DD05 DD05 DD05DD05 DD05DD05DD05 DD05DD05 DD05DD05 DD05DD05DD05DD05DD05DD05DD05DD05DD05DD07 5H622 AA02 CA01 CA06 CA13 DD02 DD04 PP19 PP20 QA03 QA08

Claims (3)

[Claims] 1. A magnet having a cylindrical shape, at least an outer peripheral surface of which is divided in the circumferential direction and magnetized alternately at different poles so as to be rotatable about a rotation center, and a coil is provided in the axial direction of the magnet. An outer magnetic pole portion arranged to be excited by the coil and facing the outer peripheral surface of the magnet; A cooling fan motor comprising a fan integrally arranged with the magnet. 2. A magnet having a cylindrical shape, at least an outer peripheral surface of which is divided into N in the circumferential direction and which is alternately magnetized to different poles and rotatable about a rotation center, and which has a coil in the axial direction of the magnet. And a comb-teeth-shaped outer magnetic pole portion which is excited by the coil and is provided on the outer peripheral surface of the magnet so as to face each other at an angle of an integral multiple of (720 / N) at a predetermined angle A degrees. And a hollow pillar-shaped inner magnetic pole portion that is excited by the coil and faces the inner peripheral surface of the magnet, and a fan integrally arranged with the magnet in the inner diameter portion of the magnet. Assuming that the respective facing angles A of the comb tooth shape of the outer magnetic pole portion facing the outer peripheral portion are A, the outer diameter dimension D1 of the magnet, and the inner diameter dimension D2 of the magnet, A> (248.4 / N)-
A cooling fan motor characterized by being set to 58.86 × (D1-D2) / (D1 × π). 3. A rotor having a hollow cylindrical magnet portion at least having an outer peripheral surface divided in the circumferential direction and alternately magnetized to different poles and rotatable about a rotation center; a first coil; A hollow of the rotor that is excited by the first coil and is excited by the first outer magnetic pole portion and the first coil that faces the outer peripheral surface of the hollow cylindrical magnet portion of the rotor within the first predetermined angle range. A first inner magnetic pole portion facing the inner peripheral surface of the cylindrical magnet portion, a second coil, and a hollow cylinder of the rotor excited by the second coil and outside the first predetermined angular range. A second outer magnetic pole portion facing the outer peripheral surface of the shaped magnet portion within a second predetermined angle range and facing the inner peripheral surface of the hollow cylindrical magnet portion of the rotor excited by the second coil. The second inner magnetic pole portion and the marker A cooling fan motor, characterized in that with the said magnet and fan which is integrally disposed on the inner diameter side of the net portion.