JPH114555A - Permanent magnet rotating machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a highly efficient permanent magnet rotating machine while reducing an eddy current on the surface of a magnet, by constituting a conductive permanent magnet with a plurality of groups of conductive unit magnet being provided side by side in the peripheral direction of a rotor. SOLUTION: A permanent magnet rotating machine consists of a stator and a rotor, the stator consists of a stator core 4 and a stator coil winding 5, the rotor is divided into the rotary direction of the rotor, and a conductive permanent magnet 6 being constituted in a group of unit magnets with a magnet width of τm1 is arranged to have each different polarity in a circumferential direction. As a result, the conductive permanent magnet 6 for stator coil winding salient poles 41 and 42 is formed by a plurality of unit magnets, thus reducing the surface area of each unit magnet and increasing electrical resistance. Therefore, an eddy current caused by harmonics magnetic flux cannot flow smoothly and the eddy current loss can also be reduced. Therefore, even if a conductive permanent magnet with a high magnetic flux density is used, a compact, light, and efficient permanent magnet rotating machine can also be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a permanent magnet rotating electric machine.

[0002]

2. Description of the Related Art It is desired that a rotating electric machine be smaller, lighter and more efficient than before. For example, when it is used for an electric vehicle such as an electric vehicle, demand for economical running and improvement of a running distance per unit of battery are desired, and for that purpose, it is necessary to be small, light and highly efficient.

It is known that a permanent magnet rotating electric machine using a permanent magnet as a magnetic flux generating means is the most suitable as a small, lightweight and highly efficient rotating electric machine.

Recently, it has been attempted to use a rare earth magnet as a permanent magnet to secure a high magnetic flux density and improve efficiency.

However, rare earth magnets have high conductivity,
Since the resistance is small, an eddy current is easily generated, which causes a reduction in efficiency.

To solve this problem, conductive permanent magnets having a high magnetic flux density represented by rare-earth magnets and non-conductive permanent magnets are alternately arranged in the axial direction of the rotor to reduce eddy currents inside the permanent magnets. What is reduced is JP-A-5-22768
No. 6 is described.

[0007]

However, the technology disclosed in the above publication uses a non-conductive permanent magnet for a part thereof, so that the utilization rate of the magnet is lower than when only a conductive permanent magnet is used. And efficiency cannot be improved.

Further, in the above technology, since the permanent magnet is made of a different material, the rotating electric machine must be constructed based on a material having a low mechanical strength among the two materials, which causes a problem that reliability is reduced. is there.

In view of the above, an object of the present invention is to provide a permanent magnet rotating electric machine that can achieve high efficiency while reducing eddy currents on the magnet surface.

[0010]

SUMMARY OF THE INVENTION An object of the present invention is to provide a stator having a stator having salient poles on which windings are wound, and a rotor which is rotatably held with a rotating gap, and which has a permanent magnet around or inside the stator. Wherein each magnetic pole of the permanent magnet comprises a plurality of conductive unit magnets arranged side by side in the circumferential direction of the rotor. Achieved by electric motor.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a sectional view of a permanent magnet rotating electric machine, FIG. 2 is a plan view of the permanent magnet rotating electric machine of FIG. 1, and FIG. 3 is a perspective view of a rotor.

In this embodiment, the number of stator winding salient poles is 12
Although the number of poles and the number of permanent magnet poles of the rotor are eight, the present invention is applicable to other salient poles and poles.

Referring to FIG. 1, a permanent magnet rotating electric machine 1 includes a stator 2 and a rotor 3, and the stator 2 includes a stator core 4 and a stator winding 5.

The rotor 3 is divided in the direction of rotation of the rotor 3 and is arranged such that the conductive permanent magnets 6 composed of a unit magnet group having a magnet width τ _m1 have different polarities in the circumferential direction. It has a configuration.

That is, as shown in FIG. 3, a permanent magnet composed of a unit magnet group having a polarity of NS and a conductive permanent magnet composed of a unit magnet group having a polarity of SN are rotated. It is inserted into a permanent magnet insertion hole 12 formed in the iron core 7 and is rotatably held by end brackets 11 and 111 via a shaft 8 and bearings 10 and 101.

Although the frame 9 is shown on the outer periphery of the stator core 4 here, the frame may be omitted if necessary.

Here, when the magnet width of the unit magnet is τ _m1 and the interval between the stator winding salient poles 41 and 42 is τ _m , τ _m1 <τ
_m .

With such a configuration, for example, the conductive permanent magnets 6 facing the stator winding salient poles 41 and 42 are formed by a plurality of unit magnets. And electrical resistance can be increased. For this reason, eddy currents due to the harmonic magnetic flux are less likely to flow, and losses due to the eddy currents can be reduced.

Therefore, even if a conductive permanent magnet having a high magnetic flux density typified by a rare earth magnet is used, a high-efficiency rotating electric machine can be realized, and a small, lightweight, and high-efficiency permanent magnet rotating electric machine can be provided.

In this embodiment, after the unit magnet of NS or SN has polarity (after magnetization), the unit magnet is inserted into the permanent magnet insertion hole 12, but after the unit magnet material is inserted, It may be magnetized. In this case, the effect of improving the work of inserting the unit magnet material can be obtained.

FIG. 4 shows another embodiment of the present invention.

The difference from the embodiment of FIG. 2 lies in that the unit magnet is formed via an insulator 13.

The insulator 13 may be inserted between the unit magnets. However, if the insulator 13 is integrally filled and fixed together with the unit magnet with an adhesive or a resin, the fixing of the unit magnet and the structure of the insulator 13 will be described. Can be obtained at the same time.

According to the above configuration, the unit magnet is made of the insulator 13
As a result, eddy current does not flow between the unit magnets, and eddy current loss can be further reduced.

In the above description, the insulator 13 is inserted or filled with an adhesive or the like.
The insulator 13 may be formed on the unit magnet in a necessary place by coating or the like in advance. In this case, a work process such as insertion of the insulator 13 or filling with an adhesive or the like can be omitted, so that an effect of improving workability can be obtained.

FIGS. 5 and 6 show another embodiment of the present invention.

The difference from the embodiment of FIG. 2 is that the height h of the unit magnet located at the center of the unit magnet group is different from the heights h1 and h2 of the unit magnets on both sides thereof.

That is, FIG. 5 shows that the height h1 of the unit magnets at both ends is smaller than the height h of the two unit magnets at the center, and FIG. 6 shows the height h of the unit magnets at the center. The height h1 and the height h2 are reduced toward the end with respect to the height h.

According to the above configuration, there is an effect that the shape of the conductive permanent magnet 6 can be easily formed such as a substantially trapezoidal shape or a substantially semicircular shape by selecting the height h of the unit magnet.

In the case where a permanent magnet having a high conductivity such as a rare earth element is not used, a substantially trapezoidal or semi-circular shape can be easily formed by selecting the height h of the unit magnet.

In the above embodiment, the shape of the magnet insertion opening 13 of the rotor core 7 and the shape of each unit magnet are substantially the same, but as shown in FIGS. 7 and 8, the permanent magnet shown in FIG. An insulating space such as an insulator 13 or an air layer may be provided between the permanent magnet insertion hole 12 and the unit magnet in the same shape as the magnet insertion hole 12 (a rectangle in this example).

According to the above configuration, since the amount of magnetic flux at both ends of the conductive permanent magnet can be suppressed, the effect of reducing the cogging torque generated between the stator winding salient pole and the magnet can be obtained.

FIG. 9 shows another embodiment of the permanent magnet rotating electric machine of the present invention.

The difference from FIG. 2 is that the width τ _{m1 of the} unit magnet at the center and the width τ _{m2 of the} unit magnet at both ends are different.

That is, in FIG. 9, τ _m2 of the unit magnets at both ends is smaller than τ _{m1 of the} four unit magnets at the center.

According to the above configuration, by changing the width τ _{m1 of the} unit magnet depending on the position of the magnet, the effect of making the shape of the conductive permanent magnet 6 closer to a trapezoid or a semicircle can be obtained.

In the above, the shape of the conductive permanent magnet 6 has been described as an example of a rectangle, but the shape of the permanent magnet is not particularly limited to an arc shape and a star shape as shown in FIGS.

The same effect can be obtained by using a structure in which the conductive permanent magnet is arranged on the surface of the rotor core.

Although the above description has been given of a permanent magnet rotating electric machine having a permanent magnet rotor structure, not only a rotating electric machine but also a generator may be used, and a rotating electric machine using an external rotation type or an internal rotation type rotor may be used. Applicable.

Further, the present invention can be applied not only to rotating electric machines but also to linear motors and the like.

[0042]

According to the present invention, by forming a conductive permanent magnet from a plurality of conductive unit magnet groups, a highly efficient permanent magnet rotating electric machine can be obtained while reducing eddy currents on the magnet surface.

[Brief description of the drawings]

FIG. 1 is a sectional view of a permanent magnet rotating electric machine according to an embodiment of the present invention.

FIG. 2 is a plan view of the permanent magnet rotating electric machine of FIG. 1;

FIG. 3 shows a perspective view of the permanent magnet rotor of FIG. 1;

FIG. 4 is a partial plan view of a permanent magnet rotating electric machine according to another embodiment of the present invention.

FIG. 5 is a partial plan view of a permanent magnet rotating electric machine according to another embodiment of the present invention.

FIG. 6 is a partial plan view of a permanent magnet rotating electric machine according to another embodiment of the present invention.

FIG. 7 is a partial plan view of a permanent magnet rotating electric machine according to another embodiment of the present invention.

FIG. 8 is a partial plan view of a permanent magnet rotating electric machine according to another embodiment of the present invention.

FIG. 9 is a partial plan view of a permanent magnet rotating electric machine according to another embodiment of the present invention.

FIG. 10 is a partial plan view of a permanent magnet rotating electric machine according to another embodiment of the present invention.

FIG. 11 is a partial plan view of a permanent magnet rotating electric machine according to another embodiment of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... rotating electric machine, 2 ... stator, 3 ... rotor, 4 ... stator core, 5 ... stator winding, 6 ... conductive permanent magnet, 7 ... rotor core, 8 ... shaft, 9 ... outer peripheral frame, 10,101
... bearings, 11, 111 ... end brackets, 12
... permanent magnet insertion holes, 13 ... insulators, 41, 42 ... stator winding salient poles.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Suetaro Shibukawa 2520 Oji Takaba, Hitachinaka-shi, Ibaraki Co., Ltd.Automotive Equipment Division, Hitachi, Ltd. (72) Inventor Osamu Koizumi 2520 Odaiba-Koba, Hitachinaka-shi, Ibaraki Co., Ltd. Hitachi, Ltd. Automotive Equipment Division

Claims (5)

[Claims] 1. A stator comprising a stator having salient poles on which windings are wound, and a rotor rotatably held by the stator with a rotating gap and having a permanent magnet provided around or inside thereof. In the permanent magnet rotating electric machine, each magnetic pole of the permanent magnet is formed by arranging a plurality of conductive unit magnets in a circumferential direction of the rotor. 2. The permanent magnet rotating electric machine according to claim 1, wherein the magnetic poles of the permanent magnet are annularly arranged in the circumferential direction of the rotor at intervals. 3. The permanent magnet according to claim 2, wherein each magnetic pole of the permanent magnet includes at least one unit magnet different in size from other unit magnets included in the same magnetic pole. Rotating electric machine. 4. The unit magnet according to claim 3, wherein the radial height of the unit magnet at the center in the circumferential direction is larger than the radial height of other unit magnets included in the same unit magnet group. Permanent magnet rotating electric machine. 5. The permanent magnet according to claim 2, wherein the rotor fills a permanent magnet insertion hole having a size larger than a cross section of the unit magnet group in a rotor circumferential direction, and a gap between the permanent magnet and the permanent magnet insertion hole. A permanent magnet rotating electric machine characterized by having an insulating material.