JP2000278894A - Motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the rotating performance of a rotor by providing a magnet to generate magnetic flux at a good efficiency to the rotor. SOLUTION: A rotor including an annular magnet 21 and a stator providing a coil are provided to rotate the rotor through commutation in the coil of stator. The magnet 21 of rotor has at least two N poles and S poles respectively against the stator and the line of magnetic force passing these N and S poles is continuous within the magnet 21.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a motor provided with a rotor provided with an annular magnet portion and a stator provided with a coil, wherein the motor rotates the rotor by causing commutation to the coil of the stator.

[0002]

2. Description of the Related Art Conventionally, brushless DC motors, stepping motors, and the like are known in which a magnet is provided on a rotor, a coil is provided on a stator, and the rotor is rotated by causing commutation to the coil. The rotor is configured to rotate on the inner circumference or the outer circumference of the stator.

[0003] Such motors are used in various types of motor engines, such as paper feeders and drum driving devices for printers.

[0004] The magnet portion provided on the rotor is for generating a field magnetic flux (magnetic flux required for generating torque), and is usually provided by being fitted into an iron core portion provided on the rotor. ing.

[0005] Alternatively, as such a magnet part, for example, as shown in FIG. 11, there is a magnet part 4 formed by assembling a plurality of magnet pieces 4a into an annular shape. The arrow in the figure indicates the magnetization direction of each magnet piece 4a, N indicates the N pole of the magnet part 4, and S indicates the S pole of the magnet part 4.

The magnet part 4 shown in FIG. 1 is a magnet piece 4 having an outer peripheral side and an inner peripheral side of the magnet part 4 magnetized to an N pole.
a, and two magnet pieces 4a magnetized to the S pole on the inner circumference side and the N pole on the outer circumference side are alternately assembled two by two.
The magnet portion 4 is provided on a rotor that rotates on the inner periphery of the stator, and the N pole and the S pole on the outer periphery of each magnet piece 4a face the stator.

A back yoke 5 is provided inside the magnet portion 4.
Are provided, and the S pole and N on the inner peripheral side of each magnet piece 4a are provided.
Lines of magnetic force passing through the poles are continuous via the back yoke 5.

That is, in such a magnet portion 4, the magnetic field lines are induced by the back yoke 5,
It is configured to generate magnetic flux satisfactorily.

[0009]

In recent years, motors have tended to be smaller and have higher performance.
A configuration that efficiently generates a magnetic flux is desired for a magnet portion provided on a rotor.

For example, in the case of the above-mentioned annular magnet portion,
A back yoke is necessary to generate magnetic flux satisfactorily,
Providing the back yoke increases the mass of the rotor, and undesirably increases the inertia of the rotor.

In view of the foregoing, an object of the present invention is to provide a motor in which the rotor has improved rotational performance by providing the rotor with a magnet portion that efficiently generates magnetic flux.

[0012]

According to a first aspect of the present invention, there is provided a rotor provided with an annular magnet portion, and a stator provided with a coil. In a motor for rotating a rotor, a magnet portion of the rotor has an N pole and an S pole facing the stator.
The motor has at least two poles, and the lines of magnetic force passing through the N pole and the S pole are continuous in the magnet unit.

As described above, according to the motor of the present invention,
The magnet portion of the rotor has at least two N and S poles facing the stator, and the lines of magnetic force passing through these N and S poles are continuous within the magnet portion. The magnetic flux can be generated efficiently, and as a result, the rotation performance of the rotor can be improved.

For example, conventionally, in such a magnet portion, a magnetic field line is induced by a back yoke,
In the present invention, the magnetic flux lines passing through the N pole and the S pole facing the stator are continuous in the magnet portion. , It is possible to satisfactorily generate magnetic flux.

According to a second aspect of the present invention, there is provided the motor according to the first aspect, wherein the magnet portion is configured by assembling a plurality of magnet pieces.

Thus, according to the motor of the present invention,
Since the magnet part is formed by assembling a plurality of magnet pieces, the magnet part can be easily created.

According to a third aspect of the present invention, there is provided the motor according to the first or second aspect, wherein the N-pole and the S-pole of the magnet portion facing the stator are each formed in a protruding shape.

Thus, according to the motor of the present invention,
Since the N pole and the S pole of the magnet section facing the stator are each formed in a projecting shape, the magnet section can efficiently generate magnetic flux.

According to a fourth aspect of the present invention, in any one of the first to third aspects, a non-magnetic material is provided between the N pole and the S pole of the magnet section facing the stator. It is a motor of a structure.

Thus, according to the motor of the present invention,
Since a non-magnetic material is provided between the N pole and the S pole of the magnet section facing the stator, the magnet section can efficiently generate magnetic flux.

[0021]

Embodiments of the present invention will be described below in detail with reference to the drawings.

As shown in FIG. 1, a motor 1 of this embodiment includes a rotor 2 having an annular magnet portion 21 and a plurality of coils 31.
The rotor 2 is configured to rotate around the rotating shaft portion 22 penetrating the magnet portion 21 by causing commutation to each coil 31 of the stator 3. .

The control of the motor 1 is performed by a control device (not shown). The control device detects the position of the rotor 2 by measuring the back electromotive force, and responds accordingly. Each coil 31 is configured to cause commutation.

FIGS. 2 to 7 are front views showing the magnet portion 21 provided on the rotor 2 respectively. Each magnet part 21 shown in these figures is formed by assembling a plurality of magnet pieces 21a, and has two N poles and two S poles facing the stator 3 respectively.
Have one. Further, the magnetization direction of each magnet piece 21a is such that the line of magnetic force passing through the N pole and the S pole of the magnet part 21 is
1 is set to be continuous. The arrow in the figure indicates the magnetization direction of each magnet piece 21a, and N indicates the magnet part 21.
N and S indicate the S pole of the magnet unit 21.

In the following description, the motor 1 provided with the magnet unit 21 shown in FIG.
The motor 1 provided with the motor unit 1 is a magnet unit 21 shown in FIG.
The motor 1 provided with the magnet part 21 shown in FIG. 5, the motor 1 provided with the magnet part 21 shown in FIG. 5 in the specific example 4, the motor 1 provided with the magnet part 21 shown in FIG. The motor 1 provided with 21 is a specific example 6.

The magnet section 21 of the first embodiment (see FIG. 2) has four magnet pieces 21a located at the north pole and the south pole of the magnet section 21.
And eight magnet pieces 21a arranged on the inner periphery thereof.

The magnet section 21 of the second embodiment (see FIG. 3) is configured by assembling four sets of eight magnet pieces 21a having gradually different magnetization directions, that is, a total of 32 magnet pieces 21a.

The magnet section 21 of the third embodiment (see FIG. 4) has four magnet pieces 21a located at the north pole and the south pole of the magnet section 21.
And eight magnet pieces 21a arranged on the inner circumference thereof. Between the N pole and the S pole of the magnet portion 21,
Each is provided with a non-magnetic body 21b.

The magnet portion 21 of the fourth embodiment (see FIG. 5) has four magnet pieces 21a located at the north and south poles of the magnet portion 21.
And four magnet pieces 21a arranged on the inner periphery thereof, and between the N pole and the S pole of the magnet portion 21,
Each is provided with a non-magnetic body 21b.

The magnet portion 21 of the specific example 5 (see FIG. 6) has four magnet pieces 21a located at the north pole and the south pole of the magnet portion 21.
And four magnet pieces 21a arranged on the inner periphery thereof, and the N pole and the S pole of the magnet portion 21 are each formed in a projecting shape (trapezoid in this example).

The magnet portion 21 of the specific example 6 (see FIG. 7) has four magnet pieces 21a located at the N pole and the S pole of the magnet portion 21.
And four magnet pieces 21a connecting these, and a non-magnetic body 21b is provided between the N pole and the S pole of the magnet part 21, respectively.

The magnetic flux density, the back electromotive voltage, and the cogging torque of the motor 1 of the first to sixth embodiments and the motor (conventional example) provided with the magnet unit 4 and the back yoke 5 of FIG. After confirming by analysis,
The results as shown in FIGS. 8, 9 and 10 were obtained.

From the graph of FIG.
It was confirmed that the magnetic flux density in the above was satisfactory.

Further, from the graph of FIG. 9, it was confirmed that the back electromotive voltages in the specific examples 1 to 6 were satisfactorily obtained. In particular, in the specific examples 3, 4, 5, and 6, the back electromotive force can be increased in a wide range as compared with the conventional example, so that the controllability by the control device can be improved. it can.

Further, it was confirmed that the cogging torque in the specific examples 1 to 6 was significantly reduced as compared with the conventional example, as shown by the amplitude in the graph of FIG. Therefore, according to the motors 1 of these specific examples, quieter and smoother rotation of the rotor 2 can be obtained.

As described above, each of the magnet portions 21 of each specific example can efficiently generate a magnetic flux, and the rotational performance of the rotor is improved.

The magnetic flux density, back electromotive force, cogging torque, etc. of the motor 1 are controlled by the magnet pieces 21 a
By appropriately setting the shape and magnetization direction, the nonmagnetic material between the N pole and the S pole, and the shapes of the N pole and the S pole, etc.,
Each can be different. That is, the magnetic flux density, the back electromotive voltage, the cogging torque, and the like can be appropriately set in order to correspond to the desired rotational performance.

In this embodiment, the magnet portion 21 having no back yoke has been described.
May be configured so that a part of the magnetic lines of force passing through the N pole and the S pole is guided by the back yoke. In this case, a relatively thin back yoke can be used as compared with a conventional back yoke that guides all lines of magnetic force.

As described above, according to the motors of the first to fifth embodiments, the rotor having the annular magnet portion is
A motor having a stator provided with a coil, and rotating the rotor by causing commutation to the coil of the stator, wherein the magnet part of the rotor has at least two N poles and S poles facing the stator, respectively. Since the magnetic lines of force passing through the N pole and the S pole are continuous in the magnet section, the magnet section can efficiently generate magnetic flux,
As a result, the rotation performance of the rotor can be improved.

For example, conventionally, in such a magnet portion, a magnetic field line is induced by a back yoke,
In the present example, the magnetic flux lines passing through the N pole and the S pole facing the stator are continuous in the magnet portion. , The magnetic flux can be satisfactorily generated.

Further, according to the motors of the first to sixth embodiments, the magnet portion is formed by assembling a plurality of magnet pieces.
The magnet section can be easily created.

Specific examples 3, 4, and 6
According to this motor, since a non-magnetic material is provided between the N pole and the S pole of the magnet section facing the stator, the magnet section can efficiently generate magnetic flux.

Further, according to the motor of the fifth embodiment, since the N pole and the S pole of the magnet portion facing the stator are each formed in a protruding shape, a magnetic flux can be efficiently generated in the magnet portion.

[0044]

According to the motor of the first aspect of the present invention, there is provided a motor having a rotor provided with an annular magnet portion and a stator provided with a coil, wherein the motor rotates the rotor by causing commutation to the coil of the stator. The magnet portion of the rotor has at least two N and S poles facing the stator, and the lines of magnetic force passing through these N and S poles are continuous within the magnet portion. The magnetic flux can be generated efficiently, and as a result, the rotation performance of the rotor can be improved.

For example, conventionally, in such a magnet portion, a magnetic field line is induced by a back yoke,
In the present invention, the magnetic flux lines passing through the N pole and the S pole facing the stator are continuous in the magnet portion. , The magnetic flux can be satisfactorily generated.

According to the motor of the second aspect of the present invention, in the first aspect, since the magnet portion is formed by assembling a plurality of magnet pieces, the magnet portion can be easily formed.

According to the third aspect of the present invention, in the first or second aspect, since the N and S poles of the magnet portion facing the stator are each formed in a protruding shape, the magnet portion efficiently generates magnetic flux. can do.

According to the motor of the fourth aspect of the present invention, in any one of the first to third aspects, a non-magnetic material is provided between the N pole and the S pole of the magnet portion facing the stator. In the section, magnetic flux can be generated efficiently.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing a motor according to a specific example of the present invention.

FIG. 2 is a cross-sectional view showing a magnet unit according to a specific example of the present invention.

FIG. 3 is a cross-sectional view showing a magnet unit according to a specific example of the present invention.

FIG. 4 is a cross-sectional view showing a magnet unit according to a specific example of the present invention.

FIG. 5 is a cross-sectional view showing a magnet unit according to a specific example of the present invention.

FIG. 6 is a cross-sectional view showing a magnet unit according to a specific example of the present invention.

FIG. 7 is a cross-sectional view showing a magnet unit according to a specific example of the present invention.

FIG. 8 is a graph showing magnetic flux density characteristics according to a specific example of the present invention.

FIG. 9 is a graph showing back electromotive force characteristics according to a specific example of the present invention.

FIG. 10 is a graph showing cogging torque characteristics according to a specific example of the present invention.

FIG. 11 is a cross-sectional view showing a magnet unit and a back yoke according to a conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Motor 2 Rotor 3 Stator 21 Magnet part 21a Magnet piece 21b Nonmagnetic material 22 Rotation shaft part 31 Coil N N pole S S pole

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 5H019 AA03 AA04 BB01 BB20 CC03 CC07 CC08 EE14 5H622 AA02 AA03 CA02 CA05 CA10 CA13 CB01 PP01 PP19 QB02 QB05

Claims (4)

[Claims] 1. A motor comprising: a rotor provided with an annular magnet portion; and a stator provided with a coil, wherein the motor rotates the rotor by causing commutation to the coil of the stator, wherein the magnet portion of the rotor is A motor having at least two N-poles and S-poles facing a stator, and wherein lines of magnetic force passing through the N-poles and the S-poles are continuous in the magnet portion. 2. The motor according to claim 1, wherein the magnet section is formed by assembling a plurality of magnet pieces. 3. The N of said magnet portion facing said stator.
The motor according to claim 1, wherein the pole and the S pole are each formed in a protruding shape. 4. The N of said magnet portion facing said stator.
The motor according to any one of claims 1 to 3, wherein a non-magnetic material is provided between the pole and the S pole.