JP2002300743A - Embedded magnet motor, and magnetic flux reinforcement method for embedded magnet motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an embedded magnet motor of a smaller make and having a higher torque by further suppressing magnetic flux leakage by increasing magnetic resistance between adjacent magnets and improving its magnetic flux passage. SOLUTION: The embedded magnet motor has a rotor 1 and a stator 5. The rotor 1 has a rotor body 3 and a plurality of magnets 8 disposed side by side in the circumferential direction on the outer periphery of the rotor body 3. Non-magnetic part/space 16 is formed, among the plurality of the magnets 8, between both ends of adjacent magnets 8A and 8B facing each other, and the radial width of an outer periphery 15 correspondingly positioned between both ends is narrower than the radial width of the outer periphery positioned to correspond to both ends. The space 16 has a high magnetic resistance. Diverted from the space by the magnetic resistance, circumferential magnetic flux (a) which passes through the outer periphery 15 correspondingly positioned between both ends is diverted to the radial direction as the cross-section area of the outer periphery 15 is narrowed, so that the magnetic flux leakage formed between the adjacent magnets 8A and 8B is decreased. Magnetic interactive force between the rotor and the stator is reinforced by decrease of such magnetic flux leakage.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an embedded magnet type motor and a method for enhancing the magnetic flux of the embedded magnet type motor.
In particular, the present invention relates to an embedded magnet type motor capable of promoting multi-polarization, and a method of enhancing magnetic flux of the embedded magnet type motor.

[0002]

2. Description of the Related Art As a small and large torque motor, a multi-pole motor is known. Such a multi-pole motor includes a stator that generates a rotating magnetic field, and a rotor that has a large number of permanent magnets arranged in a circumferential direction. The direction of the effective magnetic flux of the rotor and the magnetic direction of the permanent magnet are both in the centrifugal direction or the centripetal direction. By increasing both the number of magnetic flux generating poles and the number of magnet poles, the magnetic flux flowing through the stator is dispersed, so that the outer diameter of the stator can be reduced.
The generated torque proportional to the amount of magnetic flux and the current increases as the number of poles increases. As described above, the multi-pole type motor is widely used as a small and large torque motor.

In such a small-sized and large-torque motor, a permanent magnet is embedded in a rotor core to enhance the formation of a magnetic path formed in the rotor core, thereby enhancing the radial magnetic force of the permanent magnet. Further, the size can be reduced and the torque can be increased. When the number of poles increases and the number of poles increases, the driving frequency increases, which is disadvantageous for high-speed operation. However, since the driving frequency is not set high in a low-speed and large-torque motor, it is desirable to increase the number of poles. As the number of poles increases, the number of magnet ends increases, and the outer diameter of the rotor is limited to a small size due to a demand for miniaturization, and the distance between the ends of adjacent magnets is shortened. Such a reduction in the distance between the ends causes a new problem that the leakage magnetic flux between the adjacent magnets increases and the torque generated by the same magnet amount decreases.

In order to suppress the increase of the leakage magnetic flux, as shown in FIG. 5, the space between the circumferentially adjacent magnets is increased in order to increase the magnetic resistance between the circumferentially adjacent magnets. It is significant to consider providing such a non-magnetic portion.

[0005] By further developing such an idea,
Further, it is desired to suppress the magnetic flux leakage by improving the magnetic path formation to further reduce the size and to further increase the torque.

[0006]

SUMMARY OF THE INVENTION An object of the present invention is to increase the magnetic resistance between adjacent magnets and further improve the magnetic path, thereby further suppressing leakage magnetic flux, further reducing the size and increasing the torque. It is an object of the present invention to provide an embedded magnet type motor and a magnetic flux enhancement method for the embedded magnet type motor.

[0007]

Means for solving the problem are described as follows. The technical items appearing in the expression are appended with numbers, symbols, and the like in parentheses (). The numbers, symbols, and the like are technical items that constitute at least one embodiment or a plurality of the embodiments of the present invention, in particular, the embodiments or the examples. Corresponds to the reference numerals, reference symbols, and the like assigned to the technical matters expressed in the drawings corresponding to the above. Such reference numbers and reference symbols clarify the correspondence and bridging between the technical matters described in the claims and the technical matters of the embodiments or examples. Such correspondence / bridge does not mean that the technical matters described in the claims are interpreted as being limited to the technical matters of the embodiments or the examples.

[0008] An interior magnet type motor according to the present invention includes a rotor (1) and a stator (5), wherein the rotor (1) comprises:
A rotor main body (3), and a plurality of magnets (8) arranged in a circumferential direction on an outer peripheral region of the rotor main body (3);
A non-magnetic portion (16) is formed between opposite ends of adjacent magnets (8A, 8B) of the plurality of magnets (8),
The radial width of the outer peripheral area portion (15) corresponding to the position between the both end portions is smaller than the radial width of the outer peripheral region portion corresponding to the both end portions. It is proper that the non-magnetic part is a space.

The space which is the non-magnetic portion (16) has a large magnetic resistance. The circumferential magnetic flux (a) which is deviated from the space by the magnetic resistance and is going to pass through the outer peripheral area portion (15) corresponding to the position between both ends, becomes the outer peripheral area portion (1).
The cross-sectional area of 5) is reduced, and its direction is changed in the radial direction, so that the leakage magnetic flux formed between the adjacent magnets (8A, 8B) is reduced. Such a reduction in leakage flux enhances the magnetic interaction force between the rotor and the stator.

[0010] The non-magnetic portion (16) includes a rotor body (3).
And is divided by a radial portion (17) extending in the radial direction. Such radial part (17)
Enhances the strength of the rotor (1), but the radial thickness of its radial part may be zero (radial part is partially or not present at all).

An outer peripheral area portion (1) corresponding to a position between both ends.
The outer peripheral surface of (5) is formed as a concave surface (14) with respect to the outer peripheral surface of the outer peripheral region corresponding to both ends. The presence of the concave surface (14) further reduces the radial thickness of the outer peripheral portion (15) corresponding to the position between both ends. The non-magnetic portion (16) extends radially outward from both ends.
Such an extension further reduces the radial thickness of the outer peripheral portion (15).

A method for enhancing magnetic flux of an interior permanent magnet motor according to the present invention includes a rotor (1) and a stator (5), wherein the rotor (1) is a rotor body (3) and a rotor body (3). And a plurality of magnets (8A, 8B) arranged in a circumferential direction in an outer peripheral region (3A) of the embedded magnet type motor. 8a, 8B) between the opposing ends (1).
It is configured to increase the magnetic resistance of 5).
Increasing the size can be achieved by increasing the outer peripheral area between both ends (1).
5) forming a non-magnetic portion (16), and actively (intentionally) narrowing the magnetic path of the outer peripheral region portion (15) between both ends.

The enlargement is such that the space / non-magnetic part (16) can be divided by a part that is part of the surrounding area part (15) and extends in the radial direction. It is further preferred that the magnetic path is formed in the outermost part of the surrounding area.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Corresponding to the drawings, in an embodiment of the interior magnet type motor according to the present invention, a rotor is provided concentrically with a stator. As shown in FIG. 1, the rotor 1 includes an output shaft 2, a rotor main body 3, and a magnet row layer 4. The rotor 1, the output shaft 2, the rotor main body 3, and the magnet row layer 4 share the same rotation axis L. The outer peripheral surface of the output shaft 2 is firmly joined to the inner peripheral surface of the rotor main body 3. The magnet row layer 4 is formed in an outer peripheral cylindrical region of the rotor main body 3. The magnet row layer 4 is formed from a plurality of magnets. Each of the plurality of magnets is embedded in the outer peripheral side cylindrical region of the rotor main body 3 and arranged in a row on the same circumference. Each of the plurality of magnets is alternately opposite in the radial direction.

The stator 5 has a cylindrical stator body 6.
And a plurality of radial magnetic bodies (magnetic path forming bodies) 7. Each of the plurality of radial magnetic bodies 7 has an appropriate width in the circumferential direction, the outer peripheral side is integrally connected to the stator main body 6, and the inner peripheral side is the outer peripheral surface of the magnet row layer 4 or the rotor main body 3. Has an inner peripheral surface opposed to a small gap. The number of magnets and the number of radial magnetic bodies 7 are not the same. The radial magnetic bodies 7 form a plurality of groups, and the plurality of groups are excited by respective electromagnetic coils (not shown) and magnetized to generate a radial magnetic field for the magnet row layer 4. The magnet row layer 4 rotates by receiving a rotational force from the stator 5 due to magnetic interaction between a plurality of magnets in which the NS poles are alternately arranged and a plurality of groups of the radial magnetic bodies 7, and its rotational energy is Output from the rotor 1 to an external system. Such a motor is called an embedded magnet type electric motor.

FIG. 2 shows the embedding of the above-mentioned plural magnets arranged in a part of the outer peripheral region of the rotor body 3. FIG. 2 shows a part of each of two adjacent magnets 8A and 8B of the plurality of magnets 8. The magnet row layer 4 includes a plurality of magnets 8 and a rotor main body outer peripheral area 3A of the rotor main body 3 that wraps the plurality of magnets 8 from outside. A magnet fitting hole 9 extending in the axial direction is formed at a plurality of positions in the rotor main body outer peripheral area portion 3A. The number of the magnet fitting holes 9 is the same as the number of the plurality of magnets 8. A radially outer portion of the circumferential end of each inner surface of the magnet fitting hole 9 is formed by two intersecting inner surfaces 11 as shown in FIG. Magnet 8A and magnet 8
B is axially inserted and fitted into the two magnet fitting holes 9 respectively.

A part of the outer peripheral surface of the outer peripheral region of the rotor main body 3, which is the outer peripheral region of the rotor main body 3, is formed at a plurality of locations and has a radially concave surface (or a radial concave) which is depressed radially outward from inside. 14 is formed. The concave portion formed by the concave surface 14 is arranged in an angle range θ between the adjacent adjacent end regions of the adjacent magnets 8A and 8B or an angle range θ substantially equal to the angle range.

Between the radially concave surface corresponding position portion 17 of the rotor body outer peripheral region 3A which is within the angular range θ and extends in the radial direction corresponding to the concave surface 14 and each end of the adjacent magnets 8A and 8B. A circumferential nonmagnetic body (hereinafter, referred to as a circumferential space) 16A and a circumferential magnetic body (hereinafter, referred to as a circumferential space) 16B extending in the circumferential direction are formed respectively. The space 16A and the space 16B are spaces that are continuous in the circumferential direction. The circumferentially continuous space is geometrically defined as a space formed as a set of concentric cylindrical surfaces passing through respective end surfaces of the adjacent magnets 8A and 8B. The two adjacent spaces 16A and 16B are discontinuously formed by the radial concave surface corresponding position portions 17 whose width is reduced by the existence of these spaces. The width of the radial concave surface corresponding position portion 17 can be formed extremely narrow. Rotor body outer peripheral area 3A and magnet row layer 4
The inner part of the rotor body 3 can be joined to the inner part of the rotor body 3 by a magnet row arranged in the circumferential direction, so that there is no problem in strength even if the radially concave surface corresponding position part 17 does not exist.

Between the circumferential surface of the radial concave surface 14 and the circumferential surface forming the circumferential space 16, it is formed as a part of the rotor body outer peripheral area 3A and extends in the circumferential direction and has a radial width. Narrowed in the radial direction 15A, 15B
As shown in FIG. 3, a cross section S cut along a radial plane passing through the rotation axis of the rotor 1 is formed small (narrow).

The magnetic flux of the proximity magnets 8A and 8B hardly penetrates into the circumferential space 16 having a large magnetic resistance.
As shown in FIG. 3, an attempt is made to penetrate into the rotor main body outer peripheral area 3 </ b> A which is an iron core part around the circumferential space 16, but the radius which is a magnetic path of a part of the rotor main body outer peripheral area 3 </ b> A The cross-sectional areas of the narrow portions 15A and 15B in the direction are small, and the magnetic flux in the narrow portions 15A and 15B in the radial direction is suppressed to be small. The magnetic flux in the radial narrow portion 15A and the radial narrow portion 15B tries to wrap around the radial concave surface corresponding position portion 17, but the magnetic flux is also transmitted to the radial concave surface corresponding position portion 17 having a small cross-sectional area. Hard to penetrate. In this way, the amount of leakage magnetic flux leaking between adjacent magnets as circumferential magnetic flux is suppressed to a small value. Such suppression increases the magnetic flux between the permanent magnet and the radial magnetic body 7 of the stator, and increases the interaction magnetic force between the magnet and the stator 5.

FIG. 4 shows another embodiment of the interior magnet type motor according to the present invention. This embodiment is the same as the previous embodiment in that the radial width (thickness) of the circumferential connecting portion 15 including the radial narrow portions 15A and 15B in the angle range θ is narrow. In the present embodiment, the radial concave surface 14 of the previous embodiment is not formed, but the radial width of the circumferential space 16 of the previous embodiment is enlarged. The circumferential space 16 forms a radial space extension 18 that extends partially radially outward.

The lines of magnetic force between the adjacent magnets 8A and 8B pass through the circumferential connecting portion 15 which is closer to the outside than the magnetic flux a in the previous embodiment, and the magnetic flux entering the radially concave surface corresponding position portion 17 is more. Has been reduced, and the distance between the two endpoints of the field lines has been increased. If a through-hole (not shown) is formed in the circumferential connection portion 15 in the radial direction to penetrate the circumferential connection portion 15 in the radial direction and communicate the radial space expansion portion 18 to the outer space of the rotor body 3, the leakage magnetic flux Is further reduced. Such a decrease in the leakage magnetic flux is caused by the permanent magnets 8A and 8B and the stator 5
To increase the interaction magnetic force with the radial magnetic body 7.

The increase in the number of poles increases the leakage flux,
By reducing the cross-sectional area of the magnetic path formed by the rotor body 3 between the adjacent magnets, the magnetic resistance between the adjacent magnets increases, and the magnetic flux decreases. According to the synergistic decrease rate αβ indicated by the product of the decrease rate α of the magnetic flux of the two weakened magnetic poles and the distance extension rate β at which the distance between them becomes longer, which coincides with the increase in the length of the line of magnetic force The amount of magnetic flux leakage decreases synergistically.

[0024]

The interior magnet type motor and the magnetic flux enhancement method of the interior magnet type motor according to the present invention can synergistically suppress magnetic flux leakage and promote multi-pole.

[Brief description of the drawings]

FIG. 1 is a sectional view showing an embodiment of an interior magnet type motor according to the present invention.

FIG. 2 is a sectional view showing a part of FIG. 1;

FIG. 3 is a sectional view showing a part of FIG. 2;

FIG. 4 is a sectional view showing another embodiment of the interior magnet type motor according to the present invention.

FIG. 5 is a cross-sectional view showing a preceding device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 3 ... Rotor main body 5 ... Stator 8a, 8B ... Magnet 14 ... Concave surface 15 ... Outer peripheral area part 16 ... Space 17 ... Radial direction part a ... Magnetic line

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Hitoshi Onuma 1st highway at Iwazuka-cho, Nakamura-ku, Nagoya-shi, Aichi Prefecture Inside the Industrial Equipment Division of Mitsubishi Heavy Industries, Ltd. F-term in the Industrial Machinery Division, Mitsubishi Heavy Industries, Ltd. 5H621 AA03 BB07 GA04 HH01 JK03 5H622 AA03 CA02 CA07 CB04 PP10

Claims (10)

[Claims] 1. A rotor comprising: a rotor; and a stator, wherein the rotor comprises: a rotor main body; and a plurality of magnets arranged in a circumferential direction on an outer peripheral region of the rotor main body. A non-magnetic portion is formed between opposing ends of adjacent magnets of the plurality of magnets, and a radial width of the outer peripheral region corresponding to a position between the ends is a position corresponding to the both ends. An embedded magnet type motor that is narrower than the radial width of the outer peripheral area. 2. The interior magnet type motor according to claim 1, wherein said non-magnetic portion is a space. 3. An embedded magnet type motor according to claim 1, wherein said non-magnetic portion is a portion of said rotor body and is divided by a radial portion extending in a radial direction. 4. An embedded magnet type motor according to claim 3, wherein said radial portion has a circumferential thickness of zero. 5. An outer peripheral surface of said outer peripheral region portion corresponding to a position between said both end portions is formed to be concave with respect to an outer peripheral surface of said outer peripheral region portion corresponding to said both end portions. Interior magnet type motor. 6. An embedded magnet type motor according to claim 1, wherein said nonmagnetic portion extends radially outward from said both ends. 7. An embedded magnet type motor including a rotor and a stator, wherein the rotor has a rotor main body and a plurality of magnets arranged in a circumferential direction on an outer peripheral region of the rotor main body. A method of enhancing magnetic flux, comprising: increasing the magnetic resistance of the outer peripheral region between opposing ends of adjacent magnets of the plurality of magnets, wherein the enlarging comprises: A magnetic flux enhancement method for an embedded magnet type motor, comprising: forming a non-magnetic portion in an outer peripheral region; and positively narrowing a magnetic path in the outer peripheral region between the two end portions. 8. The method according to claim 7, wherein said enlarging further comprises dividing the space by a radially extending portion that is part of the peripheral region. 9. The method according to claim 7, wherein said enlarging further comprises forming the magnetic path at an outermost portion of the peripheral region. 10. The enlarging step includes: dividing the space by a radially extending portion that is a part of the peripheral region portion; and forming the magnetic path at an outermost portion of the peripheral region portion. 8. The method according to claim 7, further comprising the step of: