JPH0691715B2 - Rotating electric machine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial field of application) The present invention relates to an electric motor that can obtain a rotational output by supplying power, or a generator that can obtain an electric output by applying a rotational force from the outside. Regarding electric rotating machines.

(Prior Art) Generally, a rotary electric machine having a salient pole structure in which a groove is formed in an armature core for providing an armature winding has a larger number of field magnets in the armature winding than a rotary electric machine having no salient pole structure. Since the magnetic flux can be crossed, the rotating electric machine can be small and lightweight and can provide a large output. However, if the armature core has a salient pole structure,
Since the armature core has a magnetically non-uniform structure, there is a problem that cogging occurs due to interaction with a field magnet portion formed of, for example, a permanent magnet.

This will be described with reference to FIGS. 6 and 7. In FIG. 6, reference numeral 1 is a magnetic field portion formed of a ring-shaped permanent magnet magnetized to have two poles, and 2 is an armature core that constitutes an armature, which is composed of three salient pole portions 2a, 2b, With 2c. The salient pole portions 2a, 2b, 2c are opposed to the magnetized inner surface of the field magnet portion 1 with a predetermined gap, and one of the field magnet portion 1 and the armature core 2 is the other. It is freely rotatable with respect to. Reference numerals 3a, 3b and 3c are winding grooves, and 4a, 4b and 4c are three-phase armature windings wound around the salient pole portions 2a, 2b and 2c in a concentrated manner. .

Here, considering the rotary electric machine of FIG. 6 as an electric motor, the magnetic field part 1 is generated by sequentially passing currents through the armature windings 4a, 4b, 4c.
A continuous rotational torque can be obtained by the electromagnetic force generated between the armature 2 and the armature 2.

If the rotary electric machine of FIG. 6 is considered to be a generator, three-phase AC output can be obtained for the armature units 4a, 4b, 4c by rotating the field part 1 which is a rotor from the outside. .

By the way, the cogging force is generated when the magnetic energy stored in the magnetic field of the field part and the armature changes according to the relative rotation of the two, and in particular, the magnetic nonuniformity of the field part ( (Caused by the magnetic field) and magnetic non-uniformity of the armature core (caused by the groove), and as shown in FIG. 6, the magnetic field part 1 and the salient pole parts 2a, 2b, 2c of the armature core 2 are generated. If both of them have magnetic periodicity, generally, a cogging force of a harmonic component (matching component) existing in both of them is generated.

In order to deal with this point, a means for reducing the cogging force by increasing the order of the harmonic component has been proposed (for example, Japanese Patent Publication No. 58-42707). FIG. 7 shows an example of such a system. The difference from the example of FIG. 6 is that the salient pole portions 12a, 12b, 12c of the armature core 12 are different.
Of the auxiliary grooves 5a1, 5a2, 5b1, 5 in the portion facing the field part 1.
The point is that b2, 5c1, and 5c2 are provided. Incidentally, each of the above auxiliary grooves 5a
1 to 5c2 are provided in the longitudinal direction of the rotation axis of the field magnet portion 1 or the armature iron core 12, that is, the central axis passing through the center point A (direction perpendicular to the plane of the drawing).

As a result, by providing the auxiliary grooves, the number of grooves that cause cogging force is substantially increased, and the harmonic component due to the iron core has a frequency three times that of the case where two auxiliary grooves are provided. Therefore, it becomes a harmonic component and the cogging force is reduced. However, with such means, the cogging force is reduced.
However, such means is effective only in a specific case where the magnetized state of the field magnet portion is present, but has a drawback that the cogging force changes when the magnetized state changes.

Therefore, the applicant of the present invention has located a portion facing the field of the salient pole of the armature, which is offset by (360 ° / an integer multiple of the number of field poles) from the position of each groove for winding. A patent application was previously filed for a rotary electric machine having a convex portion (Japanese Patent Application No. 59-6759).

(Problems to be Solved by the Invention) According to the rotating electric machine of Japanese Patent Application No. 59-6759, the cogging forces generated by the winding grooves of the armature are offset by the protrusions, and the cogging force is reduced. It has the effect of significantly reducing it, and since the cogging force due to the winding groove is directly canceled by the convex portion, the magnetic flux waveform of the field, that is,
There is an effect that the cogging force can be reduced even if there is a variation in the magnetization with respect to the field because it is hardly affected by the magnetized state.

However, according to the rotating electric machine of the above application, the height of the convex portion of the armature needs to be high enough to cancel the cogging force due to the winding groove, and as a result, the concave portion other than the convex portion is required. In some cases, the gap between the magnetic field and the field became large, the effective magnetic flux decreased, and the torque decreased.

Also, on the salient pole of the armature, for the groove for winding (360 °
If the number of magnetic poles of the field is an even number of 4 poles or more under the condition that a convex portion is provided at a portion deviated by (number of magnetic field poles), each salient pole portion 2a of the armature 2 as shown in FIG. , 2b, 2c, not the center of the convex portion 6a, 6b, 6c may be formed in the biased portion, when the convex portion 6a, 6b, 6c is formed in such a biased portion, the armature There is also a problem that assembly becomes complicated because the front and back sides of No. 2 have different shapes.

An object of the present invention is to provide a rotating electric machine that utilizes the cogging prevention principle of the invention according to the above application, increases the effective magnetic flux without impairing the cogging prevention effect, and increases the torque.

(Means for Solving the Problems) In the rotating electric machine of the present invention, 2n (where n is an integer of 2 or more) poles are magnetized to the field magnet, and the field magnets are opposed to the salient poles. Opposite to the cogging force generated by the above-mentioned winding groove at each salient pole portion that is offset by (360 ° / an integer multiple of the number of field poles) from the position of each winding groove Is provided with a convex portion that generates the cogging force.

(Operation) The cogging force generated by one winding groove of the armature and the cogging force generated by the plurality of convex portions of each salient pole act in opposite directions to cancel each other, thereby reducing the cogging force. The cogging force of a plurality of protrusions in each salient pole for canceling the cogging force generated in one winding groove may be divided by a fraction, and thus the height of each protrusion should be The height can be lowered as compared with the case where only one protrusion is provided on the pole.

(Embodiment) In FIG. 1, reference numeral 21 is a field composed of an annular permanent magnet magnetized to have four poles in the circumferential direction, 22 is an armature composed of an iron core, and this armature 22 has three parts. It has one salient pole 22a, 22a, 22c. The salient poles 22a, 22b, 22c are opposed to the inner surface of the field magnet 21 with a predetermined gap, and either one of the field magnet 21 and the armature 22 is rotatable with respect to the other. . A groove 2 for winding is provided between the salient poles 22a, 22b, 22c.
3a, 23b, 23c are formed, and three-phase armature winding 24 is formed at the base of each salient pole 22a, 22b, 22c through the grooves 23a, 23b, 23c.
A, 24b, and 24c are wound by concentrated winding.

Each salient pole 22a, 22b, 22c of the armature 22, in a portion facing the field 21, a plurality of convex portions 22a1, 22a2, 22a3, 22b1, 22b2, 22b3, for each salient pole 22a, 22b, 22c, 22c1, 22c2,
22c3 is provided. These convex portions 22a1 to 22c3 are provided at positions shifted by 90 ° and 180 ° with respect to the winding grooves 23a, 23b, 23c, respectively.

Generally speaking, the number of magnetic poles of the field and the portion of the convex portion provided on each salient pole of the armature are 2n (where n is 2).
The above-mentioned integer), and the portion of the convex portion provided on each salient pole of the armature is (3) with respect to the position of each groove 23a, 23b, 23c for the winding.
The position is shifted by 60 ° / an integer multiple of the number of magnetic poles), and if this condition is satisfied, the cogging force can be reduced.

According to the above general conditions, the number of poles of the field magnet 21 of the embodiment of FIG. 1 and the formation portion of each of the convex portions 22a1 to 22c3 will be described. N is 2 and the number of poles of the field magnet is 4 poles. Grooves 23a, 23b, 23c
On the other hand, each of the convex portions 22a1 to 22c3 is provided at a portion deviated by 90 ° which is (360 ° / the number of magnetic poles) and a portion deviated by 180 ° obtained by multiplying 90 ° by an integer 2.

Next, the cogging reducing action of the rotary electric machine according to the embodiment shown in FIG. 1 will be described with reference to FIG. In the state shown in FIG. 3, the armature 22 moves to the right relative to the field 21, causing the salient pole 22a to move away from the N pole of the field 21, thereby generating a cogging force. , Field 21
Salient poles 22a, 22b, 22c at neutral points B, C, D of each magnetic pole of
The convex portions 22a3, 22b2, and 22c1 are about to enter, which causes cogging force. The former cogging force generated on the salient pole 22a and the latter convex portions 22a3, 22b2, 22c1
The cogging forces generated in the opposite directions are opposite to each other, and the cogging forces cancel each other out.

As described above, in the above-described embodiment, since the cogging force is canceled by the three convex portions with respect to one groove of the armature 22, each convex portion provided with three salient poles has three convex portions. The cogging force to be shared is only one-third, so the second
As shown in the figure, the height t of each protrusion 22a1 to 22c3
Can be made lower than in the case where one salient pole is provided with one protrusion as in the invention according to the above-mentioned application. Therefore, the gap between the field other than each convex portion of the armature and the field can be significantly reduced, and the number of convex portions provided on one salient pole is also increased. The effective magnetic flux between the child and the child can be greatly increased, and the torque can be increased.

In addition, as shown in FIG. 2, each convex portion 22a1 to 22c3
It is preferable that the angle θ1 is equal to the angle θ2 of each groove 23a, 23b, 23c, but from the allowable range of generated torque and cogging, if it is in the range of θ1 = (0.5 to 2.0) · θ2, there is a practical problem. Absent.

4 and 5 show another embodiment of the present invention. In the embodiment shown in FIG. 4, n is 4, the number of magnetic poles of the field 31 is 8, and three salient poles 32a, 32b, 32c are formed on the armature 32.
A plurality of convex portions is provided for each salient pole at a portion of the coils 32b, 32c facing the field 31 with respect to the positions of the winding grooves 33a, 33b, 33c.
60 ° / field pole number) 45 ° and 90 which is an integral multiple of this
It is provided at the positions shifted by °, 135 ° and 180 °.

In the embodiment of FIG. 5, n is 2, the number of magnetic poles of the field 41 is 4, and the armature 42 has five salient poles 42a, 42b, 42c, 42d, 42e.
A plurality of convex portions are formed for each salient pole at the portions of the salient poles 42a to 42e facing the field magnet 41.
It is provided at a portion deviated from the positions of 3b, 43c, 43d, and 43e by (360 ° / the number of field poles), which is 90 °, and 180 ° which is an integral multiple thereof.

Also in the case of the embodiment shown in FIGS. 4 and 5, the same effects as the effects explained in the embodiment of FIG. 1 are exhibited.

(Effect of the Invention) According to the present invention, the cogging force generated by one winding groove can be canceled by the cogging force generated by the plurality of convex portions provided on each salient pole. The height of the convex portion can be made lower than that when one convex portion is provided for each salient pole. Therefore, the effective magnetic flux is increased by the synergistic effect that the gap of the armature with respect to the field other than the above-mentioned convex portions can be reduced, and that the number of convex portions close to the field increases and the area increases. So,
A rotating electric machine with large torque can be provided while effectively preventing cogging.

[Brief description of drawings]

FIG. 1 is a sectional view showing an embodiment of the present invention, FIG. 2 is an enlarged sectional view showing an essential part of the same embodiment, and FIG. 3 is a view showing that the cogging force is reduced in the above embodiment. FIG. 4 is a sectional view showing another embodiment of the present invention, FIG. 5 is a sectional view showing still another embodiment of the present invention, and FIG. 6 is a conventional rotation. FIG. 7 is a sectional view showing an example of an electric machine, FIG. 7 is a sectional view showing another example of a conventional rotating electric machine, and FIG. 8 is a sectional view showing yet another example of a conventional rotating electric machine. 21, 31, 41 ... Field, 22, 32, 42 ... Armature, 22a, 22b, 22
c, 32a, 32b, 32c, 42a, 42b, 42c, 42d, 42e ... salient poles, 23a, 23b, 23c, 33a, 33b, 33c, 43a, 43b, 43c, 43d,
43e ... Grooves for winding, 22a1, 22a2, 22a3, 22b1, 22b2, 22b3, 22c1, 22c2, 22
c3 ... convex part.

Claims (1)

[Claims] 1. A rotary electric machine in which an armature having a winding groove and salient poles is disposed so as to face a field magnet, and one of the armature and the field magnet is rotated with respect to the other. The field is magnetized with 2n poles (where n is an integer of 2 or more), and the salient poles of the armature face the field and are located at the positions of the winding grooves. On the other hand, the salient poles that are offset by (360 ° / an integer multiple of the number of field poles) are each provided with a convex portion that generates a cogging force opposite to the cogging force generated by the groove for the winding. And rotating electrical machinery.