JP2598770Y2 - Rotating electric machine - Google Patents

Description

[Detailed description of the invention]

[0001]

In the present invention, the ratio of the number of magnetic poles of a field magnet to the number of salient poles of an armature core is 8: 9 or 10: 9.
More particularly, the present invention relates to a rotating electric machine with reduced cogging torque.

[0002]

2. Description of the Related Art Conventionally, a field magnet has eight magnetic poles,
There is known a rotating electric machine having a so-called 8-6 configuration in which the number of salient poles of an armature core provided opposite to the field magnet is six. Also, a rotating electric machine having an 8-12 configuration in which the field magnet has eight magnetic poles and the armature iron core has twelve salient poles is known.

However, the conventional rotating electric machine has a disadvantage that the cogging torque generated due to the non-uniform magnetic resistance depending on the rotational position of the rotor is large, and thus the rotation is not smooth.

For this reason, various configurations for further reducing the cogging torque have been proposed. For example, as described in U.S. Pat. No. 4,858,044, an 8-9 configuration in which the number of magnetic poles of a field magnet is 8, and the number of salient poles (number of slits) of an armature iron is 9 is provided. Has been proposed. It has also been proposed to adopt a 10-9 configuration in which the number of magnetized poles of the field magnet is 10 and the number of slits of the armature iron core is 9.

[0005]

With the various configurations proposed above, a much smaller cogging torque can be easily obtained as compared with conventional motors of the general 8-6 configuration or 8-12 configuration. . However, even with these configurations, the cogging torque cannot be reduced to zero. Therefore, when the smoothness of rotation is required more strictly, it is necessary to further reduce the cogging torque.

In view of the above problems, the present invention provides a rotating electric machine having an 8-9 configuration or a 10-9 configuration that can further reduce cogging torque while suppressing deterioration in characteristics. With the goal.

[0007]

According to the present invention, in order to achieve the above object, the ratio of the number of magnetic poles of a field magnet to the number of salient poles of an armature iron core provided opposite to the field magnet is 8%. : 9 or 10: 9, the field magnet is subjected to skew magnetization inclined with respect to the rotation axis direction, and the inclination angle of the skew magnetization is adjusted in a plane facing the armature core. And the electrical angle is 20 ± 5 ° or 40 ± 5 °.

[0008]

In a rotating electric machine having an 8-9 configuration or a 10-9 configuration, skew magnetization is applied to the field magnet in a plane facing the armature core with respect to the direction of the rotation axis so that cogging torque is obtained. Can be reduced. The cogging torque also changes greatly depending on the magnitude of the inclination angle (skew angle) of the skew magnetization.

The skew angle is set to an electric angle of 20 within a range facing the armature core of the field magnet.
It was found that when the angle was in the range of ± 5 °, good characteristics were obtained and the cogging torque could be kept low. Good characteristics can be obtained even when the skew angle is in the range of 40 ± 5 degrees in electrical angle. Therefore, with the above configuration, the cogging torque can be suppressed low. In the case of a motor, for example, a decrease in torque constant can be suppressed to a minimum.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the rotating electric machine of the present invention will be described below with reference to the drawings, taking a motor (inner rotor type motor) as an example. In FIG. 1, a motor 1 includes a rotor having a ring-shaped armature core 3 and a ring-shaped field magnet 2. The armature core 3 is a laminated core formed by stacking a plurality of core plates as shown in FIG. 2 (b), and has nine salient poles 4 directed toward the center on the inner peripheral side.
have. The salient poles 4 are arranged at equal intervals in the circumferential direction, and the tip of each salient pole 4 is an umbrella portion 5 extending on both sides in the circumferential direction. A total of nine slots 6 are formed between these nine umbrella parts 5.

The field magnet 2 and the rotor having the same are arranged on the inner peripheral side of the umbrella portion 5 of the salient pole 4 of the armature core 3. The outer peripheral surface of the field magnet 2 and the inner peripheral surface of each umbrella portion 5 face each other at a fixed interval. The field magnet 2 is magnetized to eight poles in the circumferential direction. As shown in FIG. 2A, the eight magnetic poles of the field magnet 2 are skew-polarized with respect to the direction A of the rotation axis of the rotor. The skew angle, which is the inclination angle of the skew magnetization, is 20 ° in electrical angle in a plane facing the armature core 3 as shown in FIG. 2 and 5 ° in mechanical angle as shown in FIG.

Here, the skew angle will be described in detail. First, the spread angle of one magnetic pole of the field magnet 2 in the circumferential direction is 180 ° in electrical angle as shown in FIG. The boundary line 2 a between the magnetic poles of the field magnet 2 is inclined with respect to the rotation axis direction A. And, more precisely, in the overlapping plane of the field magnet 2 and the armature core 3,
Boundary line 2 in the overlapping plane of armature core 3 and umbrella 5
The divergence angle in the circumferential direction between both ends of a is called a skew angle. This skew angle is usually represented by an electrical angle. Therefore, even when the inclination of the boundary line 2a of each magnetic pole of the field magnet 2 with respect to the rotation axis direction A is the same, the field magnet 2
The skew angle differs depending on the size of the overlapping surface of the armature core 3 with the umbrella portion 5.

FIG. 3 shows an embodiment in which the width of the armature core 13 in the rotation axis direction A at the salient pole umbrella portion 15 is smaller than the width of the field magnet 2 in the rotation axis direction. The skew angle in this embodiment is also set to 20 ° as in the embodiment of FIG. In this case, the skew angle is an angle in the circumferential direction between both ends of the boundary line 2a of each magnetic pole of the field magnet 2 in the overlapping plane of the field magnet 2 and the umbrella portion 15 of the armature core 13. The inclination of the boundary line 2a of each magnetic pole of the field magnet 2 with respect to the rotation axis direction A is larger than that in the example of FIG.

Next, the relationship between the skew angle and the cogging torque or torque constant when the skew angle of the field magnet is changed in the motor having the 8-9 configuration according to the present invention will be described with reference to FIGS. 5 is shown. In addition, 1
Similar characteristics can be obtained in the case of the 0-9 configuration.

As is apparent from FIG. 4, the cogging torque decreases as the skew angle increases from 0 electrical angle, and becomes minimum when the skew angle is 20 electrical degrees. Thereafter, the cogging torque increases and then decreases with the skew angle, and becomes minimum again when the skew angle is 40 ° in electrical angle.

In general, if the skew angle of the field magnet is increased, the magnetic flux linking the armature windings is reduced, and the torque constant of the motor is reduced. Is not preferred. Also in the embodiment of the present invention, as is apparent from FIG. 5, when the skew angle exceeds 45 °, the decrease in the torque constant becomes so large that it cannot be ignored.

In the embodiment of the present invention, if the skew angle of the field magnet is set to 20 ° in electrical angle,
The cogging torque is reduced, and the torque constant is not reduced. For this reason, in the embodiment of the present invention, the skew angle of the field magnet is 20 electrical degrees.
The vicinity is the optimum value. If the skew angle is within a range of ± 5 ° around 20 °, the cogging torque can be suppressed to a relatively small value, and the decrease in the torque constant can be reduced. Therefore, a range where the skew angle is 20 ± 5 ° is a preferable range.

Further, by setting the skew angle of the field magnet to 40 ° in electrical angle, a change in cogging torque due to a change in the skew angle of the magnetization is small, so that the cogging torque can be reduced stably and the torque constant can be reduced. Reduction can be reduced. Therefore, the skew angle of the field magnet is preferably around 40 ° in electrical angle. If the skew angle is in a range of ± 5 ° with respect to 40 °, the cogging torque can be suppressed to a relatively small value and the decrease in the torque constant can be reduced. Therefore, a range where the skew angle is 40 ± 5 ° is also a preferable range.

There are various methods for winding the armature core around the salient poles.
There is no difference due to the difference in the winding method. Therefore, description of the winding method is omitted.

In the rotating electric machine according to the present invention, the ratio of the number of magnetic poles of the field magnet to the number of salient poles of the armature core is 8:
9 or 10: 9, and these may be multiplied by n (n is an integer). That is, the present invention is applied to 8n
The present invention is applied to a rotating electric machine including a field magnet magnetized to a pole or a 10n pole and an armature core having 9n salient poles provided to face the field magnet.
For example, n may be 2 and the number of magnetic poles of the field magnet may be 16 or 20, and the number of salient poles of the armature core may be 18.

In addition, various design changes can be made without departing from the spirit of the present invention. For example, while FIG. 1 shows an inner rotor type in which the rotor is inside the armature core and the windings, the present invention can of course be applied to an outer rotor type having an opposite configuration. The present invention is applicable not only to motors but also to generators.

[0022]

As described above, according to the rotating electric machine according to the present invention, in the rotating electric machine in which the ratio of the number of magnetic poles of the field magnet to the number of salient poles of the armature core is 8: 9 or 10: 9, The cogging torque is obtained by applying skew magnetization inclined to the rotation axis direction to the magnetic magnet and setting the skew angle to 20 ± 5 ° or 40 ± 5 ° in electrical angle in the plane facing the armature core. And a rotating electric machine with smooth rotation can be obtained. Further, when the rotating electric machine is a motor, it is possible to further minimize the decrease in the torque constant.

[Brief description of the drawings]

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

FIG. 2A is a development view of a field magnet in an embodiment when the width of the field magnet is equal to the lamination thickness of the armature core, and FIG. 2B is a development view of the armature core.

3A is a development view of a field magnet in another embodiment in which the width of the field magnet is wider than the lamination thickness of the armature core, and FIG. 3B is a development view of the armature core.

FIG. 4 is a diagram showing a relationship between a skew angle of a field magnet and a cogging torque in the rotating electric machine according to the present invention.

FIG. 5 is a diagram showing a relationship between a skew angle of a field magnet and a torque constant in the rotating electric machine of the present invention.

[Explanation of symbols]

 2 Field magnet 3 Armature iron core 4 Salient pole

Claims (1)

(57) [Scope of request for utility model registration] 1. A rotating electric machine wherein the ratio of the number of magnetic poles of a field magnet to the number of salient poles of an armature core provided opposite to the field magnet is 8: 9 or 10: 9. Is subjected to skew magnetization inclined with respect to the rotation axis direction, and the inclination angle of the skew magnetization is set to an electrical angle of 20 ± 5 ° or 40 ± 5 ° in a plane opposed to the armature core. A rotating electric machine characterized by the above-mentioned.