JP2003219618A - Permanent magnet motor, and rotor therefor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a PM motor which reduces the leakage magnetic flux not contributing to torque. <P>SOLUTION: This PM motor is equipped with a stator (2) and a rotor which rotates by the mutual magnetic action received from the stator (2). The rotor (1) includes a rotor magnetic substance (4) connected to the main shaft (3), a plurality of permanent magnets (5) joined with the first face (4a), opposed to the stator (2), of the rotor magnetic substance (4), and a magnetic piece (6) joined with the second face (5a) on the peripheral side of the permanent magnet (5). The third face (5b) in the circumferential direction of the permanent magnet (5) faces space. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a permanent magnet motor (hereinafter referred to as "PM motor").

[0002]

2. Description of the Related Art A rotating field type PM motor is known as a motor having a small size and high efficiency. The PM motor is composed of a stator that generates a rotating magnetic field and a rotor that has a large number of permanent magnets arranged in the circumferential direction. Due to the magnetic interaction between the rotating magnetic field generated by the stator and the magnetic field generated by the permanent magnets of the rotor, the rotor receives a rotational force and rotates.

In such a PM motor, the number of poles is being increased in order to increase the generated torque and reduce the size. By increasing both the number of poles of the rotor and the number of coils that generate the rotating magnetic field, the magnetic flux flowing through the stator is dispersed, so that the outer diameter of the stator can be reduced. As described above, the multi-pole PM motor is widely used as a motor having a small size and a large torque.

On the other hand, when the PM motor has multiple poles, the distance between the end portions of the permanent magnets is shortened and the leakage magnetic flux between the adjacent permanent magnets is increased. The increase of the leakage flux causes a new problem that the torque generated with the same magnet amount decreases.

It is desired that the PM motor is further miniaturized and further increased in torque by suppressing leakage flux by improving the magnetic path formation.

[0006]

SUMMARY OF THE INVENTION An object of the present invention is to provide a PM motor with reduced leakage flux that does not contribute to torque generation.

[0007]

[Means for Solving the Problems] Means for solving the problems will be described below by using the numbers and symbols used in the embodiments of the present invention. These numbers / codes are added to clarify the correspondence between the description in [Claims] and the description in [Embodiment of the Invention]. However,
The added numbers / codes should not be used to interpret the technical scope of the invention described in [Claims].

The PM motor according to the present invention has a stator (2).
And a rotor (1, 1 ') that rotates by magnetic interaction received from the stator (2). Rotor (1,
1 ') is a rotor magnetic body (4) connected to the main shaft (3)
And a plurality of permanent magnets (5) joined to the first surface (4a) of the rotor magnetic body (4) facing the stator (2), and the second surface on the outer peripheral side of the permanent magnet (5). A magnetic piece (6) joined to (5a). The third surface (5b) on the circumferential side of the permanent magnet (5) faces the space. In the PM motor, since the third surface (5b) on the circumferential side of the permanent magnet (5) faces the space, the magnetic resistance in the circumferential direction is increased, and the third surface (5b) on the outer circumferential side of the permanent magnet (5) is increased. The magnetic reluctance in the radial direction is reduced by the magnetic piece (6) joined to the two surfaces (5a). As a result, the field magnetic flux generated by the permanent magnet (5) is induced in the radial direction, and the leakage magnetic flux is reduced.

A space is preferably occupied between two adjacent permanent magnets (5) of the permanent magnets (5). This maximizes the magnetic resistance in the circumferential direction,
The leakage flux is further reduced.

The fourth surface (6a) on the outer peripheral side of the magnetic piece (6) is preferably formed into a convex curved surface.
As a result, the magnetic field flux generated by the permanent magnet (5) is induced in the thickest portion of the magnetic piece (6), and the magnetic field flux is further localized in the radial direction.

The PM motor is further made of a non-magnetic material and surrounds the outer circumference of the magnetic piece (6) to fasten the magnetic piece (6) to the rotor magnetic body (4) side. It is preferably provided with a ring (7). As a result, the structure of the rotor (1 ′) is strengthened without disturbing the localization of the field magnetic flux generated by the permanent magnet (5) in the radial direction.

The PM motor rotor according to the present invention comprises a main shaft (3) and a rotor magnetic body (4) connected to the main shaft (3).
And a plurality of permanent magnets (5) joined to the first surface (4a) of the rotor magnetic body (4) facing the stator (2), and the second surface on the outer peripheral side of the permanent magnet (5). And a magnetic piece (6) joined to (5a). The third surface (5b) on the circumferential side of the permanent magnet (5) faces the space.

[0013]

DETAILED DESCRIPTION OF THE INVENTION Referring to the accompanying drawings,
An embodiment of the PM motor according to the present invention will be described.

(First Embodiment) In the first embodiment of the PM motor according to the present invention, as shown in FIG.
The rotor 1 is provided concentrically with the stator 2. The rotor 1 includes a main shaft 3, a rotor body 4, a plurality of permanent magnets 5,
And a plurality of magnetic material pieces 6. The main shaft 3 is a rotating shaft of the rotor 1, and is concentrically joined to the rotor body 4. The rotor body 4 has a facing surface 4a facing the stator 2, and a permanent magnet 5 is bonded to the facing surface 4a.

The permanent magnets 5 are arranged side by side at equal intervals on the same circumference. The permanent magnet 5 generates a field magnetic flux in the centrifugal direction or the centripetal direction. Two adjacent permanent magnets 5
The direction of the magnetic field flux generated by is opposite.

The stator 2 includes an armature core 7, a stator frame 8,
And an armature coil 9. The armature core 7 is joined to the stator frame 8. The armature core 7 is on the same circumference,
The rotors 1 and 2 are held side by side at equal intervals and face the rotor 1 via a minute gap. The armature core 7 is wound by the armature coil 9. The armature coil 9 is supplied with an armature current and generates a rotating magnetic field. A rotational force is applied to the rotor 1 by the magnetic interaction between the generated rotating magnetic field and the field magnetic flux generated by the permanent magnet 5.

FIG. 2 is an enlarged view of a part of the rotor 1.
The space between two adjacent permanent magnets 5 is occupied by a space, and the surface 5b on the circumferential side of the permanent magnet 5 faces the space. On the outer peripheral surface 5a of the permanent magnet 5, a magnetic material piece 6 is formed.
Are joined respectively. The outer surface 6 of the magnetic piece 6
a is formed in a convex curved surface.

The structure of the rotor 1 shown in FIG. 2 reduces leakage flux. The surface 5b on the circumferential side of the permanent magnet 5 is
By facing the space, the magnetic resistance between two adjacent permanent magnets 5, that is, the magnetic resistance in the circumferential direction increases. Further, on the outer peripheral surface 5a of the permanent magnet 5, the magnetic piece 6
The magnetic resistance in the radial direction is reduced and the magnetic field magnetic flux generated by the permanent magnet 5 is localized in the radial direction due to the bonding of the two. Due to the increase of the magnetic resistance in the circumferential direction and the localization of the field magnetic flux in the radial direction, the leakage magnetic flux is reduced and the magnetic flux in the radial direction of the rotor 1 is strengthened.

At this time, the space between the two adjacent permanent magnets 5 is occupied by the space, so that the two adjacent permanent magnets 5 are adjacent to each other.
The magnetic resistance between the two permanent magnets 5 is maximized, and the leakage flux is further reduced.

Furthermore, since the outer peripheral surface 6a of the magnetic piece 6 is formed into a convex curved surface, the leakage magnetic flux is reduced. Since the outer peripheral surface 6a of the magnetic piece 6 is formed into a convex curved surface, the field magnetic flux generated by the permanent magnet 5 is
The thickness of the magnetic piece 6 is guided to the thickest part. As a result, the field magnetic flux is localized in the radial direction, and the leakage magnetic flux is further reduced.

In the present embodiment, the leakage magnetic flux is reduced,
As a result, the magnetic flux in the radial direction of the rotor 1 is strengthened. As a result, a PM motor that can be more easily miniaturized and that has a larger torque can be realized.

(Second Embodiment) In the second embodiment,
Instead of the rotor 1 shown in FIG. 1, a rotor 1 ′ shown in FIG. 3 is used. The rotor 1'is the first of the implementations.
The rotor 1 of the embodiment has a structure in which a ring 7 is added. The ring 7 is a non-magnetic material such as Inconel and is formed of a material having high strength. Ring 7
It is provided so as to be in contact with the outer peripheral surface 6a of the magnetic piece 6,
The permanent magnet 5 and the magnetic piece 6 are clamped and held toward the rotor body 4. This prevents the permanent magnet 5 and the magnetic piece 6 from coming off the rotor body 4 when the rotor 1 rotates at high speed. At this time, since the ring 7 is made of a non-magnetic material, the component of the permanent magnet 5 that leaks in the circumferential direction of the magnetic field flux generated in the radial direction is suppressed.

In the second embodiment, as in the first embodiment, the leakage flux is reduced and the ring 7 strengthens the structure of the rotor 1 '.

[0024]

According to the present invention, there is provided a PM motor having a reduced leakage flux which does not contribute to the generation of torque.

[Brief description of drawings]

FIG. 1 is a first embodiment of a PM motor according to the present invention.
The morphology is shown.

FIG. 2 is an enlarged view of the rotor 1.

FIG. 3 is a second embodiment of the PM motor according to the present invention.
The morphology is shown.

[Explanation of symbols]

1, 1 ': rotor 2: Stator 3: Spindle 4: Rotor body 5: Permanent magnet 6: Magnetic piece 7: Ring

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Naonobu Shinoda             1 Takamichi, Iwatsuka-cho, Nakamura-ku, Nagoya-shi, Aichi               Mitsubishi Heavy Industries Nagoya Research Center F term (reference) 5H619 AA01 AA03 BB01 BB15 BB24                       PP02 PP05 PP06 PP08                 5H621 GA04 HH01                 5H622 AA03 CA02 CA05 CA07 CA10                       CA11 CB01 CB05 PP16

Claims (5)

[Claims] 1. A stator, and a rotor that rotates by a magnetic interaction received from the stator, wherein the rotor is a rotor magnetic body connected to a main shaft, and the rotor magnetic body includes: A plurality of permanent magnets bonded to the first surface facing the stator; and a magnetic piece bonded to the second surface on the outer peripheral side of the permanent magnet, the first magnet on the circumferential side of the permanent magnet. Three sides are permanent magnet motors facing the space. 2. The permanent magnet electric motor according to claim 1, wherein between two adjacent permanent magnets among the permanent magnets,
Permanent magnet motor occupied in space. 3. The permanent magnet electric motor according to claim 1, wherein the outer peripheral fourth surface of the magnetic piece is formed into a convex curved surface. 4. The permanent magnet electric motor according to claim 1, further comprising a non-magnetic body, and surrounding the outer peripheral side of the magnetic body piece to surround the magnetic body piece on the rotor magnetic body side. Permanent magnet electric motor with a ring to tighten. 5. A main shaft, a rotor magnetic body connected to the main shaft, a plurality of permanent magnets joined to a first surface of the rotor magnetic body facing the stator, and an outer circumference of the permanent magnet. And a magnetic piece bonded to the second surface of the permanent magnet, wherein the third surface of the permanent magnet on the circumferential side faces the space.