JPH10174414A - Pulse-drive type brushless motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a pulse-drive type brushless motor, which can attain low cost and size reduction with a simple structure, and which requires no magnetic pole position sensor such as a Hall element and is capable of rotational drive by only applying a single pulse train. SOLUTION: This brushless motor is provided with a rotor 2, constituted so that three rotor poles 2a to 2 of identical polarity, consisting of a permanent magnet, may be formed at equal intervals on its circumference, the first stator pole 4 consisting of an electromagnet which is energized with the same polarity as the rotor poles, and the second stator pole 5 consisting of an electromagnet which has smaller pole area than the first stator pole 4. The second stator pole 5 is disposed at a circumferential position (180+α) deg. (α is a prescribed deflection angle) with respect to the first stator pole 4, and an auxiliary pole 6 consisting of a permanent magnet of the same polarity as the rotor poles is fixed at the magnetic pole face of the second stator pole 5 for forming an air gap G of the magnetic pole face of the first stator pole 4 along the rotational direction of the rotor 2, so as to be asymmetrical.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pulse-driven brushless motor suitable for use as a motor for generating vibration in a vibrator such as a portable telephone or a pager.

[0002]

2. Description of the Related Art Some portable telephones and pagers are provided with a vibrating caller which is called by vibration (vibration) in order to avoid inconvenience to the surroundings. This vibrating caller is configured to generate a vibration by attaching a weight having an eccentric center of gravity to a rotating shaft of a motor and rotating the weight. Conventionally, as a vibration generating motor for such a vibration caller, DC has been used.
Micromotors with small brushes were common.

[0003]

However, in the case of a motor with a brush, electric noise and mechanical noise generated during rotation become a problem. In particular, there is a problem that it is expensive to take measures against electric noise. To solve this noise generation, a brushless motor or a stepping motor may be used.However, in the case of a brushless motor, it is necessary to accurately detect the magnetic pole position of the rotor in order to generate a rotating magnetic field. There is a problem that a position sensor is indispensable, the structure becomes complicated and the cost becomes high. Further, in the case of a stepping motor, a driving circuit having a complicated circuit configuration is required to generate a rotating magnetic field, and there is a problem that the cost is high.

The present invention has been made to solve the above problem, and does not require a magnetic pole position sensor such as a Hall element, and can be rotationally driven only by applying a single pulse train. An object of the present invention is to provide a pulse-driven brushless motor that is simple, inexpensive, and can be miniaturized.

[0005]

In order to achieve the above-mentioned object, a pulse-driven brushless motor according to the present invention comprises: a rotor having three rotor poles of the same polarity formed of permanent magnets formed at equal intervals on a circumference; A first stator pole made of an electromagnet excited to the same polarity as the rotor pole, and a second stator made of an electromagnet excited to a different polarity from the rotor pole and having a smaller pole area than the first stator pole. A stator pole, and the second stator pole is disposed at a position in a circumferential direction (180 + α) ° (α is a predetermined angle of deviation) with respect to the first stator pole, and the second stator pole is provided. An auxiliary pole made of a permanent magnet having the same polarity as that of the rotor pole is fixed to the magnetic pole face, and an air gap of the magnetic pole face of the first stator pole is asymmetrical along the rotation direction of the rotor. To do That.

[0006]

In the pulse-driven brushless motor of the present invention having the above-mentioned structure, when a unipolar driving pulse to be turned on / off is applied to the first and second stator poles composed of electromagnets, the first stator poles A magnetic pole having the same polarity as the rotor pole is generated, and a magnetic pole having a polarity different from that of the rotor pole is generated on the second stator pole by canceling the magnetic pole of the auxiliary pole. As a result, a rotational force is generated between the rotor pole and the first and second stator poles by a magnetic repulsive force and an attractive force, and the rotor rotates.

[0007]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows a pulse-driven brushless motor according to the present invention (hereinafter abbreviated as “motor”).
1 shows a first embodiment. The first embodiment is an example of a so-called inner rotor type motor in which a rotor is positioned inside a stator and rotates. A rotor 2 rotates inside an outer case 1 forming a yoke (yoke). The rotor 2 is rotatably supported by a shaft 3. Outside the rotor 2,
First stator pole 4 made of an electromagnet having a large magnetic pole area
And a second stator pole 5 composed of an electromagnet having a magnetic pole area smaller than that of the first stator pole 4. The rotor 2 is made of a ferromagnetic material such as ferrite, and has three rotor poles 2a, 2b, and 2c made of permanent magnets magnetized so that the outer surface side is an S pole.
It is formed at intervals.

The second stator pole 5 is clockwise deviated from a position 200 ° clockwise from the first stator pole 4, that is, a position 180 ° opposite to the first stator pole 4. The first and second stator poles 4 and 5 have drive windings 7 and 8 wound therearound, respectively, and the second stator pole 5 An auxiliary pole 6 made of a permanent magnet whose outer surface is an S pole is fixed to the magnetic pole surface. When a drive pulse, which will be described later, is applied to the windings 7 and 8, the first stator pole 4 generates the same S pole as the rotor pole, and the second stator pole 5 includes the auxiliary pole. The winding direction and the number of windings are set so that the S pole of No. 6 is canceled and the N pole opposite to the rotor pole is generated.
Further, the first stator pole 4 and the rotor poles 2a to 2c
Is formed in an asymmetrical shape in which the gap decreases in the direction of rotation of the rotor indicated by arrow a, and the direction of rotation of the rotor 2 is always clockwise as indicated by arrow a. It is devised as follows.

The motor having the above-mentioned structure is finished in an external shape as shown in FIG. 2, and a semi-cylindrical weight 9 is attached to the end of the rotating shaft 3 extending from the outer case 1 to the outside.
By causing the rotor 2 to be eccentrically rotated by the weight 9, the entire motor is configured to vibrate.

Next, the operation of the motor according to the first embodiment will be described with reference to FIGS. FIG. 3 is an explanatory diagram of the rotation state of the rotor 2, and FIG. 4 is a waveform diagram of a drive pulse applied to the windings 7 and 8. First, in a non-excited state where no drive pulse is applied to the drive windings 7 and 8, only the auxiliary pole 6 attached to the magnetic pole surface of the second stator pole 5 has a magnetic pole as shown in FIG. It is alive as. Therefore, the S pole is generated in the second stator pole 5 by the auxiliary pole 6, and the magnetic flux of the auxiliary pole 6 flows in the first stator pole 4 through the outer case 1, so that it is weak. An N pole has occurred. Therefore, a magnetic repulsive force acts between the second stator pole 5 and the second and third rotor poles 2b and 2c, and the first stator pole 4 and the first rotor pole 2a. A magnetic attraction acts between them. For this reason, the rotor 2
3A is stationary in the state shown in FIG. 3A where the attractive force and the repulsive force are balanced and the potential energy is most stable.

Now, in the non-excitation state shown in FIG.
When the drive pulse P shown in FIG. 4 is applied to the drive windings 7 and 8, the excitation state of the motor becomes as shown in FIG. That is, while an S pole is generated in the first stator pole 4,
The second stator pole 5 cancels the S pole of the auxiliary pole 6 and
Poles occur. For this reason, a strong repulsive force acts between the first stator pole 4 and the first rotor pole 2a, and the second stator pole 4 and the second and third rotor poles 2B, 2B.
and c. As a result, the rotor 2 starts rotating in the direction of arrow A (clockwise) due to the strong repulsive force acting between the first stator pole 4 and the first rotor pole 2a. At this time, an air gap G is formed on the magnetic pole surface of the first stator pole 4 such that the gap gradually decreases in the rotation direction of the rotor 2 (arrow A).
Is formed, the rotor 2 always starts rotating in the direction of arrow A.

When the rotor 2 starts rotating clockwise as described above, the second stator pole 5 and the third rotor pole 2c approach each other.
The suction force acting between the stator pole 5 and the third rotor pole 2c is also applied, so that the rotor 2 further rotates clockwise in a vigorous manner.

The application of the driving pulse P is continued until the state shown in FIG. When the drive pulse P is turned off at the time when the motor is rotated to the position shown in FIG.
As shown in (D), only the auxiliary pole 6 is active again as a magnetic pole. Therefore, an S pole is generated in the second stator pole 5 by the auxiliary pole 6, and a weak N pole is generated in the first stator pole 4 by the action of the auxiliary pole 6. Therefore, an attractive force acts between the first stator pole 4 and the second rotor pole 2B, and the second
A repulsive force acts between the first stator pole 5 and the third rotor pole 2c. Therefore, the rotor 2 continues to rotate in the direction of arrow a by the suction force and the repulsion force, and
(E), and further rotate to the state of FIG. 3 (F).

When the rotor 2 rotates to the state shown in FIG. 3F, the three rotor poles 2a, 2b and 2c are
The positions are shifted by degrees and the positions are interchanged, and the electromagnetically becomes exactly the same as the state of FIG. Then, in the state of FIG. 3F, when the drive pulse P is turned on again as shown in FIG.
3 (B), 3 (C),
The rotation continues as shown in (D), (E), and (F). Therefore, the drive pulse P which is turned on / off in the same manner thereafter
Is continuously applied, the rotor 2 continues to rotate,
It becomes a motor.

As is apparent from the above description of operation, the motor rotates 1/3 every one pulse of the driving pulse P,
One rotation is performed by three pulses. Therefore, the driving pulse P
, The rotational speed of the motor can be freely changed. Further, the drive pulse P to be applied may be a single pulse train that is turned ON / OFF at a predetermined duty ratio. Therefore, unlike the conventional stepping motor, a plurality of pulse trains having slightly different phases are not required, so that the configuration of the drive circuit is extremely simplified. Further, since it is not necessary to detect the positions of the magnetic poles 2a to 2c of the rotor 2, a magnetic pole position sensor such as a Hall element is not required unlike a conventional DC brushless motor, and the structure of the motor itself is extremely simple and downsized. be able to.

In the case of the first embodiment described above, FIG.
As shown in a combination (1) in the table, the three rotor poles 2a to 2c are S poles, the first stator pole 4 is an S pole, and the second
Although the stator pole 5 is configured to have the N-pole and the auxiliary pole 6 is configured to be the S-pole, as shown in the combination (2), the same can be realized even if the polarities are completely reversed.

FIG. 6 shows a second embodiment of the present invention.
The second embodiment is an example of a so-called outer rotor type motor in which the rotor is positioned outside the stator and rotates, and the position of the rotor and the stator in the first embodiment is reversed. is there.

That is, in the case of the motor of the second embodiment, a rotor 12 is rotatably supported by a rotating shaft 13 inside an outer case 11, and an electromagnet having a large magnetic pole area is provided inside the rotor 12. , And a second stator pole 15 made of an electromagnet having a smaller magnetic pole area than the first stator pole 14 are provided. The rotor 12 is made of a ferromagnetic material such as ferrite, and has three rotor poles 12a, 12b, and 12c made of permanent magnets magnetized so that the inner surface of the rotor 12 becomes an S pole.
Are formed at 120 ° intervals on the circumference.

The second stator pole 15 is provided with a first
At a position 200 ° clockwise away from the stator pole 14 of the first stator pole 14, that is, at a position advanced clockwise by a deviation angle α = 20 ° from a position 180 ° opposite to the first stator pole 14; First and second stator poles 14,
Drive windings 17 and 8 are wound around 15, and an auxiliary pole 16 made of a permanent magnet whose outer surface is an S pole is fixed to the magnetic pole surface of the second stator pole 15. I have. When a drive pulse P as shown in FIG. 4 is applied to the windings 17 and 18, the same S pole as the rotor pole is generated in the first stator pole 14, and
The winding direction and the number of windings of the second stator pole 15 are set such that the S pole of the auxiliary pole 6 is canceled and an N pole opposite to the rotor pole is generated. Further, the first
The air gap G formed between the stator poles 14 and the rotor poles 12a to 2c has an asymmetric shape in which the distance between the stator poles 14 and the rotor poles 12a to 2c decreases in the rotation direction of the rotor 12 as indicated by an arrow a. It is designed so that the direction is always clockwise as indicated by arrow A.

In the motor according to the second embodiment, only the positions of the rotor and the stator are reversed inside and outside, and the operation itself is exactly the same as that of the first embodiment. FIG. 7 shows only the operation state diagram of the rotor corresponding to FIG. 3 described above, and detailed description of the operation is omitted. Also in the case of the second embodiment, as shown in FIG. 8, the rotor poles 12a to 12c and the stator poles 14, 1 are arranged.
5. The polarity of the auxiliary pole 16 may be reversed.

[0021]

As described above, according to the present invention, a rotor in which three rotor poles of permanent magnets having the same polarity are formed at equal intervals on the circumference is excited, and the rotor poles are excited to the same polarity as the rotor poles. A first stator pole made of an electromagnet, and a second stator pole made of an electromagnet that is excited to a polarity different from that of the rotor pole and has a smaller pole area than the first stator pole. The stator poles of the first
And an auxiliary pole made of a permanent magnet having the same polarity as that of the rotor pole is fixed on the magnetic pole surface of the second stator pole. Since the air gap of the magnetic pole surface of the first stator pole is asymmetrically arranged along the rotation direction of the rotor, there is no need for a magnetic pole position sensor such as a Hall element, and rotational driving is performed only by applying a single pulse train. Thus, it is possible to obtain a pulse-driven brushless motor that is simple in structure, inexpensive, and compact.

[Brief description of the drawings]

FIG. 1 is a principle structural diagram of a motor according to a first embodiment.

FIG. 2 is an external perspective view showing a state where an eccentric weight is attached to the motor of FIG. 1;

FIG. 3 is an explanatory diagram of a rotation state of a rotor in the motor according to the first embodiment.

FIG. 4 is a waveform diagram of a drive pulse used in the motor according to the first embodiment.

FIG. 5 is a combination diagram of a stator pole and a rotor pole in the motor according to the first embodiment.

FIG. 6 is a principle structural diagram of a motor according to a second embodiment.

FIG. 7 is an explanatory diagram of a rotation state of a rotor in a motor according to a second embodiment.

FIG. 8 is a combination diagram of a stator pole and a rotor pole in the motor according to the second embodiment.

[Explanation of symbols]

 Reference Signs List 1 outer case 2 rotor 2a first rotor pole 2b second rotor pole 2c third rotor pole 3 rotating shaft 4 first stator pole (electromagnet) 5 second stator pole (electromagnet) 6 auxiliary pole (permanent magnet) 7) drive winding 8 drive winding 9 weight 11 outer case 12 rotor 12a first rotor pole 12b second rotor pole 12c third rotor pole 13 rotation axis 14 first stator pole (electromagnet) 15 second Stator pole (electromagnet) 16 Auxiliary pole (permanent magnet) 17 Drive winding 18 Drive winding

Claims (1)

[Claims] 1. A rotor in which three rotor poles of the same polarity made of permanent magnets are formed at equal intervals on a circumference, a first stator pole made of an electromagnet excited to the same polarity as the rotor poles, A second stator pole made of an electromagnet that is excited to a polarity different from that of the rotor pole and has a smaller magnetic pole area than the first stator pole, and wherein the second stator pole is provided with respect to the first stator pole. (180 + α) ° (α is a predetermined deviation angle), and an auxiliary pole made of a permanent magnet having the same polarity as the rotor pole is fixed to the magnetic pole surface of the second stator pole. A pulse-driven brushless motor, wherein an air gap of a magnetic pole surface of the first stator pole is asymmetrical along a rotation direction of the rotor.