JPH06327206A - Pm type synchronous motor - Google Patents

Abstract

PURPOSE:To provide a PM type synchronous motor in which high torque and high speed rotation can be achieved. CONSTITUTION:This PM type synchronous motor has a rotor 6 in which a plurality of permanent magnets 7 are provided in circumferential form and a stator 1 in which a plurality of excitation coils 3 are provided in coaxial form with respect to the rotor 6. A spacer 9 is provided between the adjacent permanent magnets 7, thereby reducing the magnetic reluctance of magnetic flux due to a magnetizing current. Thereby, the number of magnetic flux due to the magnetizing current is increased and consequently the attraction and repulsion between the stator 1 and the rotor 6 are increased, so that the torque of the stator 1 and the rotor 6 may be increased and the high-speed rotation of the rotor 6 may be achieved.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a PM type AC synchronous motor, and more particularly to a PM type AC synchronous motor rotor capable of achieving high torque and high speed rotation in a PM type AC synchronous motor used in machine tools and the like. Regarding the structure.

[0002]

2. Description of the Related Art FIG. 3 is a sectional view of a conventional PM type AC synchronous motor. As shown in FIG. 3, the PM type AC synchronous motor has a rotor 6 in which a plurality of permanent magnets 7 are circumferentially arranged.
And a stator 1 in which a plurality of exciting coils 3 are arranged concentrically with the rotor 6. The polarities of the permanent magnets 7 are arranged in the radial direction so that adjacent magnets have mutually different polarities. The exciting coil 3 is sequentially U,
V and W are repeatedly formed, and each coil has U phase, V phase,
A three-phase AC voltage composed of the W phase is applied.

In FIG. 3, the three-phase alternating current is applied to each of the exciting coils 3 of the stator 1 at a predetermined time,
Coil magnetic fluxes Φ _c3a , Φ _c3b , and Φ _c3c are shown as examples of the coil magnetic flux when the rotor 6 is in a predetermined position. As an example of the permanent magnet 7 located at a position facing the coil magnetic fluxes Φ _c3a , Φ _c3b , and Φ _c3c , permanent magnets 7a, 7b,
7c is shown.

The coil magnetic flux Φ _c3a is oriented counterclockwise, and the directions of the coil magnetic fluxes Φ _c3a , Φ _c3b , and Φ _c3c are opposite to each other. The coil magnetic flux Φ _c3a and the S pole of the permanent magnet 7a _face each other,
The permanent magnet 7a and the coil magnetic flux Φ _c3a repel each other. Further, the S pole of the permanent magnet 7a and the coil magnetic flux Φ _{c3 b}
Φ attracts each other. At this time, counterclockwise torque is generated in the rotor 6 and counterclockwise rotational force is generated in the rotor 6.

Further, the coil magnetic flux Φ _c3b is oriented in the clockwise direction, and the coil magnetic flux Φ _{c3 b} and the permanent magnet 7 are
The N pole of b is opposed, and the permanent magnet 7b and the coil magnetic flux Φ _c3b
And each other repel each other. In addition, the N of the permanent magnet 7b is
The pole and the coil magnetic flux Φ _c3c attract each other. At this time, counterclockwise torque is generated in the rotor 6 and counterclockwise rotational force is generated in the rotor 6.

The coil magnetic flux Φ _c3c and the permanent magnet 7c
Also between the S poles, a counterclockwise torque is generated in the rotor 6 and a counterclockwise rotational force is generated in the rotor 6, as described above.

As described above, the counterclockwise rotational force is generated in the rotor 6, and the amplitude intensity and the polarity of the three-phase alternating current change as the time progresses from the predetermined time, and the coil magnetic flux Φ _c3a. , Φ _c3b , Φ _c3c move counterclockwise, the positional relationship between the coil magnetic fluxes _{c3 a} , Φ _c3b , Φ _c3c and the permanent magnets 7a, 7b, 7c is the same as that at the predetermined time, and the rotor 6 Keeps spinning.

[0008]

When the above-mentioned PM type AC synchronous motor is used for, for example, a machine tool spindle motor or the like, a recent NC processing machine or the like is required to have a high torque and a high speed rotation.

In the conventional PM type AC synchronous motor, when an AC voltage is applied to the exciting coil to rotate the coil magnetic flux, the repulsive force is generated between the coil magnetic flux and the magnet magnetic flux.
Also, a suction force is generated, which causes a driving force to be generated in the rotor, which causes the rotor to rotate. The rotation of the magnet magnetic flux caused by the rotation of the rotor causes counter electromotive force in the coil,
Reduce the drive voltage. This back electromotive force is proportional to the rotation speed of the rotor, and increases as the rotation speed increases. Therefore, as the rotation speed increases, the drive voltage decreases and the torque decreases. As a result, it has been difficult to rotate the PM type AC synchronous motor at high speed.

The present invention has been made to solve the above problems, and an object thereof is to realize a PM type AC synchronous motor capable of achieving high torque and high speed rotation.

[0011]

SUMMARY OF THE INVENTION The present invention is a PM type having a rotor in which a plurality of permanent magnets are circumferentially arranged and a stator in which a plurality of exciting coils are arranged concentrically with the rotor. In the AC synchronous motor, of the permanent magnets,
A magnetic body is arranged between the adjacent permanent magnets.

That is, according to the present invention, the leakage magnetic flux of the coil magnetic flux is concentrated on the magnetic body provided on the rotor,
The coil magnetic flux is sufficiently secured so that a sufficiently high torque can be output even in the high speed rotation region.

[0013]

In the present invention, the magnetic resistance of the magnetic flux due to the magnetizing current is reduced by disposing the magnetic body between the permanent magnets adjacent to each other in the rotor.

[0014]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows a sectional view of a PM type AC synchronous motor according to this embodiment, in which a spacer 9 made of a magnetic material is arranged between adjacent permanent magnets 7.

In order to explain the effect of the spacer 9 which is characteristic of this embodiment, a comparison will be made with the gap 5 of the conventional AC synchronous motor shown in FIG. According to the conventional example, in FIG. 3, there is a gap 5 due to air or the like between the permanent magnets 7a and 7b and between the permanent magnets 7b and 7c.
And, 7b and 7c are separated. Since the air or the like in the gap 5 has a lower magnetic permeability than the stator 1 and the rotor 6, it restricts the area of the magnetic path through which the coil magnetic fluxes such as the coil magnetic fluxes Φ _c3a , Φ _c3b and Φ _c3c pass, and The area forming the magnetic path by the magnetic flux is narrowed. The narrowing of the region forming this magnetic path means that the coil magnetic fluxes Φ _c3a , Φ
It becomes a magnetic resistance of the coil magnetic flux such as _c3b , Φ _c3c, etc., which is a cause of reducing the number of magnetic flux of this coil magnetic flux.

However, in FIG. 1 according to this embodiment,
By arranging a magnetic material having a magnetic permeability similar to that of the stator 1 and the rotor 6 between the permanent magnets 7a and 7b and between 7b and 7c, the area of the magnetic path through which the coil magnetic flux passes can be widened. It is possible to increase the number of magnetic fluxes. Therefore, according to this embodiment, the coil flux [Phi _c1a through the spacer 9, [Phi _c1b, number of magnetic fluxes of the [Phi _c1c the gap 5
The number of magnetic fluxes of the coil magnetic fluxes Φ _c3a , Φ _c3b , and Φ _c3c passing through is larger than the number of magnetic fluxes.

Next, the operation will be described with reference to FIG. As shown in FIG. 1, the AC synchronous motor includes a rotor 6 in which a plurality of permanent magnets 7 are circumferentially arranged, and a stator 1 in which a plurality of exciting coils 3 are concentrically arranged with the rotor 6. Have. The polarities of the permanent magnets 7 are arranged in the radial direction so that adjacent magnets have mutually different polarities. The exciting coil 3 sequentially forms U, V and W phases, and a voltage of three-phase alternating current composed of U phase, V phase and W phase is applied to each coil.

In FIG. 1, the three-phase alternating current is applied to each of the exciting coils 3 of the stator 1 at a predetermined time,
As an example of a coil magnetic flux when the rotor 6 is in position, showing the coil flux [Phi _c1a, [Phi _c1b, the [Phi _c1c. The coil flux Φ _c1a, Φ _c1b, as an example of the permanent magnet 7 in a position opposed to [Phi _c1c, permanent magnets 7a, 7b,
7c is shown.

[0019] The coil flux Φ _c1a is a counter-clockwise direction, the coil magnetic flux Φ _c1a, Φ _c1b, the direction of the magnetic flux of Φ _c1c is, next to each other has become a reverse to each other. The coil magnetic flux Φ _c1a and the S pole of the permanent magnet 7a _face each other,
The permanent magnet 7a and the coil magnetic flux Φ _c3a repel each other. Further, the S pole of the permanent magnet 7a and the coil magnetic flux Φ _{c1 b}
Φ attracts each other. At this time, counterclockwise torque is generated in the rotor 6 and counterclockwise rotational force is generated in the rotor 6.

Further, the coil magnetic flux Φ _c1b has a clockwise direction, and the coil magnetic flux Φ _{c1 b} and the permanent magnet 7 are
The N pole of b _faces each other, and the permanent magnet 7b and the coil magnetic flux Φ _c1b
And each other repel each other. In addition, the N of the permanent magnet 7b is
The pole and the coil magnetic flux Φ _c1c attract each other. At this time, counterclockwise torque is generated in the rotor 6 and counterclockwise rotational force is generated in the rotor 6.

The coil magnetic flux Φ _c1c and the permanent magnet 7c
Also between the S poles, a counterclockwise torque is generated in the rotor 6 and a counterclockwise rotational force is generated in the rotor 6, as described above.

As described above, the counterclockwise rotational force is generated in the rotor 6, and the amplitude intensity and the polarity of the three-phase alternating current change as the time progresses from the predetermined time, and the coil magnetic flux Φ _c1a , [Phi _c1b, if [Phi _c1c moves counterclockwise, the coil flux Φ _c1a, Φ _c1b, Φ _c1c and the permanent magnets 7a, 7b, the positional relationship 7c becomes the same as when the predetermined time, the rotor 6 Keeps spinning.

[0023] Here, as described above, according to this embodiment, the coil flux [Phi _{c1 a} through spacers 9, [Phi _c1b, [Phi
_c1c is the coil magnetic flux Φ _c3a , Φ _c3b passing through the gap 5,
It _has more magnetic flux than Φ _c3c . Therefore, the stator 1
The attraction force and repulsion force between the rotor 6 and the rotor 6 increase, the torque between the stator 1 and the rotor 6 increases, and the rotor 6 can rotate at high speed.

FIG. 2 shows torque characteristics with respect to the rotation speed of the brushless motor, where the horizontal axis represents the rotation speed and the vertical axis represents the torque. The solid line shows the characteristic without the spacer, and the dotted line shows the characteristic with the spacer. Compared to the case without a spacer, the case with a spacer has high torque and
Although it is rotating at high speed, as described above, this can be changed from the gap 5 of the conventional example to the spacer 9 of the present invention.
By replacing the magnetic resistance is reduced, the coil flux _{Φ c3a,} Φ _c3b, Φ c3c coil flux [Phi from _c1a, [Phi
_{Like c1b} and Φ _c1c, the number of magnetic flux of the coil magnetic flux increases,
This is because the attractive force and the repulsive force between the stator 1 and the rotor 6 increase, the torque between the stator 1 and the rotor 6 increases, and the rotor 6 can rotate at high speed.

As described above, according to the present invention, the PM type AC synchronous motor capable of achieving high torque and high speed rotation can be realized by disposing the magnetic body between the adjacent permanent magnets. And

[0026]

As described above, in the present invention,
By disposing the magnetic body between the adjacent permanent magnets of the rotor, the magnetic resistance of the magnetic flux due to the magnetizing current is reduced.
Therefore, the number of magnetic fluxes due to the magnetizing current increases, and the attraction force between the stator and the rotor and the repulsion force increase,
A torque of the stator and the rotor is increased, and a PM type AC synchronous motor capable of achieving high-speed rotation of the rotor can be realized.

[Brief description of drawings]

FIG. 1 is a sectional view for explaining an operation of a PM type AC synchronous motor according to the present invention.

FIG. 2 is a diagram for explaining torque-rotation speed characteristics of a PM type AC synchronous motor according to the present invention.

FIG. 3 is a sectional view for explaining an operation of a conventional PM type AC synchronous motor.

[Explanation of symbols]

 1 Stator 3 Exciting coil 5 Gap 6 Rotor 7 Permanent magnet 9 Spacer

Claims (1)

[Claims] 1. A PM type AC synchronous motor having a rotor having a plurality of permanent magnets arranged in a circumferential shape, and a stator having a plurality of exciting coils concentrically arranged with the rotor. Among them, a PM type AC synchronous motor characterized in that a magnetic material is arranged between adjacent permanent magnets.